CN101771346A - Single-stage high power factor isolating type AC to DC converter with leakage inductance energy loopback function - Google Patents
Single-stage high power factor isolating type AC to DC converter with leakage inductance energy loopback function Download PDFInfo
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- CN101771346A CN101771346A CN200810187781A CN200810187781A CN101771346A CN 101771346 A CN101771346 A CN 101771346A CN 200810187781 A CN200810187781 A CN 200810187781A CN 200810187781 A CN200810187781 A CN 200810187781A CN 101771346 A CN101771346 A CN 101771346A
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Abstract
The invention discloses a single-stage high power factor isolating type AC to DC converter with leakage inductance energy loopback function; the converter comprises a buck-boost circuit, a transformer, a switch, an input capacitance and an output circuit, wherein the buck-boost circuit is used for boosting or depressurizing a power source; the transformer is electrically connected with the buck-boost circuit and used for converting the boosted power source or the depressurized power source; the switch is electrically connected with the buck-boost circuit; the input capacitance is electrically connected with the buck-boost circuit; and the output circuit is used for outputting the power source converted by the transformer; when the switch is cut off, the buck-boost circuit provides an energy returning route so as to return the energy stored in the leakage inductance of the transformer to the input capacitance. The converter uses the energy returning route for returning the energy stored in the leakage inductance of the transformer in a fly-back type converter or a forward converter to the input capacitance. By the mode, the leakage inductance problem of the transformer of the fly-back type converter or the forward converter can be solved without needing other components to be added, thus further promoting the efficiency of circuits.
Description
Technical field
The present invention relates to about a kind of interchange direct current transducer, particularly a kind of single-stage high-power-factor isolated form of tool leakage inductance energy loop back function exchanges direct current transducer.
Background technology
Conventional AC is to commonly used being combined as of direct current transducer, prime uses voltage-boosting converter (Boostconverter), buck-converter (Buck converter) or step-down/up type transducer (Buck-boostconverter) as power factor correcting circuit, the post-stage drive circuit of arranging in pairs or groups again, as forward-type converters (Forwardconverter) or direction flyback converter (Flyback converter), reach electrical isolation and output voltage is converted to the accurate position of setting, make the voltage stable operation drive load.Under the framework of traditional two-stage type, because of the converter circuit of two groups of independent controls of needs, so circuit cost is higher; Twice power transfer also can cause circuit efficiency to reduce simultaneously.
Fig. 1 contains the high merit of stage type of step-up/step-down circuit (Buck-Boost PFC) and direction flyback converter (Flyback converter) because of isolated form exchanges direct current transducer for prior art is disclosed, be made of direction flyback converter and step-up/step-down circuit.Include a filter circuit 110, in order to AC power Vac is carried out filtering, filter circuit 110 is made up of filter inductance Lf and filter capacitor Cf.Filtered power supply then carries out rectification by the rectification circuit 120 that diode Dr1, Dr2, Dr3, Dr4 are formed.Step-up/step-down circuit 130 is to be made up of inductance L b, capacitor C dc and diode D, also has a switch S 1 in addition.Direction flyback converter 140 utilizes switch S 2 high frequencies to switch, and dc draws energy from capacitor C, and transfers the energy to secondary side by transformer T, reaches the effect that changes voltage quasi position and electrical isolation.130 of step-up/step-down circuits utilize switch S 1 high frequency to switch, and the control input current is reached the effect of merit because of revising.Output rectifier Do and output capacitance Co then are used for filtering.
Fig. 2 is that the high merit of stage type of disclosed step-up/step-down circuit of prior art (Buck-Boost PFC) and forward converter (Forward converter) exchanges direct current transducer because of isolated form, is made up of step-up/step-down circuit (Buck-Boost PFC) and forward converter (Forward converter).Similar with Fig. 1, so similar assembly uses identical label.
Develop the power factor correcting circuit that at present, operating frequency, allows the input power supply and loads in sizable scope to change to hundreds of kHz from tens of, harmonic distortion can be suppressed to hardly to exist, and merit is because of also being close in one.Direct current can be divided into six kinds of buck, boost type, step-down/up type, Qiu Ke formula (C ú k converter), SEPIC formula and Zeta formulas etc. to the basic circuit framework of direct current transducer according to the energy storage inductor and the relative position of switch initiatively.Wherein, be easy to reach the purpose of merit with the circuit framework of boost type and step-down/up type again because of revising.No matter with the current work of energy storage inductor in the continuous current pattern (Continuous-Current-Mode, CCM) or the discontinuous current pattern (Discontinuous-Current-Mode DCM), all can reach the purpose of high merit because of revising.For same power output, inductance works in the discontinuous current pattern has bigger peak current than the continuous current pattern, and power is big more, and peak current is big more, and the switch cost of circuit also increases thereupon.Therefore, the continuous current pattern is fit to be applied to high-power output.Yet, when inductance works in the continuous current pattern, control circuit must be detected the relation of input voltage, inductive current and output voltage at any time, circuit is comparatively complicated, and at each input voltage in the cycle, its switch switching frequency and responsibility cycle must change always, and when as if consideration power factor correcting circuit being integrated into the single-stage framework with a back level transducer, the switching frequency of both switch modules is necessary consistent with responsibility cycle.Therefore when power factor correcting circuit works in the continuous current pattern, be unfavorable for integrating with back level transducer; On the contrary, for the step-down/up type transducer,, then allow inductance work in the discontinuous current pattern and can reach the function of merit easily because of revising if the switching frequency of switch module and responsibility cycle all are maintained fixed in each input power cycle.
Yet, when reality is used direction flyback converter, because the circuit working principle and the design of direction flyback converter can make that transformer leakage inductance (Leakage Inductor) is bigger.Therefore, the energy that is stored in the transformer leakage inductance also can be more.In Fig. 1, the active switch S 2 of direction flyback converter is ended, and when energy was delivered to Circuit Fault on Secondary Transformer, energy stored did not have the path to lead off in the transformer primary side leakage inductance.Can produce very big surging this moment, causes bigger circuit loss, makes circuit efficiency reduce.Therefore, many in recent years scholar advanced persons are devoted to lead off the research that is stored in transformer primary side leakage inductance self-energy, have also proposed many methods.The technology of for example a kind of being called as " active clamping (Active Clamp) ".The active clamping technology is to utilize clamping capacitance to catch to be stored in the interior leakage energy of transformer primary side leakage inductance, by system it is circulated once more and delivers to load and get back to input, thereby produce near loss-free buffer.This can solve the problem of direction flyback converter leakage inductance, significantly promotes circuit efficiency.But the active clamping technology must add initiatively a switch and a capacitor at least, can make circuit cost improve, and also comparatively complicated in the control.
In addition, the design of Fig. 1 and Fig. 2 needs two groups of control circuits and two active switches, also can increase circuit cost.
Summary of the invention
For improving present interchange to direct current transducer, make it possess high merit because of, high circuit efficiency, reach the minimizing circuit unit simultaneously, the purpose that reduces cost, the present invention integrates step-up/step-down circuit and direction flyback converter or forward converter, proposes a single-stage high-power-factor isolated form and exchanges direct current (AC-to-DC, AC/DC) transducer, and utilize the drive circuit of this circuit as load (for example LED), reach merit because of revising, promote efficient and reducing the purpose of circuit cost.The single-stage converter circuit that disclosed embodiment proposed according to the present invention can be with being transmitted back on the input capacitance of energy on the transformer leakage inductance in the circuit, and then promote conversion efficiency.
The single-stage high-power-factor isolated form of disclosed tool leakage inductance energy loop back function exchanges direct current transducer according to the present invention, includes a step-up/step-down circuit, uses a power supply is boosted or step-down; One transformer electrically connects with this step-up/step-down circuit, boosts or the power supply of step-down in order to change this; One switch electrically connects with this step-up/step-down circuit; One input capacitance electrically connects with this step-up/step-down circuit; And an output circuit, in order to export the power supply after this transformer conversion; Wherein when this switch ended, this step-up/step-down circuit provided an energy reverse-path, is recycled to this input capacitance with the energy in the leakage inductance that will store this transformer.
The interior energy of transformer leakage inductance that the present invention utilizes the energy reverse-path will be stored in direction flyback converter or the forward converter is recycled to input capacitance.In this way, needn't add other assembly again, just can solve the leakage inductance problem of the transformer in direction flyback converter or the forward converter, and then promote circuit efficiency.
The interchange of disclosed embodiment is to DC converting circuit according to the present invention, removes to possess the advantage that electrical isolation is arranged, and can reach the industry demand of high merit because of, high efficiency and low cost (minimizing circuit unit).
The disclosed embodiment according to the present invention, except the merit that meets safety because of revising (PFC) require, and can reach the output of electrical isolation (meeting safety), many windings and adjust the function of voltage quasi position by transformer, applicable to various alternating voltage, avoid when line voltage shakiness or rapid drawdown, causing the unsettled situation of output.In addition power factor correcting circuit and circuit for power conversion are integrated into the single-stage converter circuit, can simplify circuit structure and reduce the package count that uses, and then reach the purpose that reduces cost.
Disclosed embodiment is integrated into the single-stage converter circuit with power factor correcting circuit and circuit for power conversion according to the present invention, because of reducing the one-level power transfer, can reach the purpose that promotes conversion efficiency.Compared to the stage type framework, the circuit of single stage type framework is easy to control, and twice LC filtering, and output ripple voltage is very little.
More than about the explanation of the explanation of content of the present invention and following execution mode be in order to demonstration with explain spirit of the present invention and principle, and provide the further explanation of claim protection range of the present invention.
Description of drawings
Fig. 1 contains step-up/step-down circuit (Buck-Boost PFC) and direction flyback converter (Flyback converter) for prior art the is disclosed high merit of stage type exchanges direct current transducer because of isolated form;
Fig. 2 is that the high merit of stage type of disclosed step-up/step-down circuit of prior art (Buck-Boost PFC) and forward converter (Forward converter) exchanges direct current transducer because of isolated form;
Fig. 3 is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges the embodiment to direct current transducer;
Fig. 4 A figure to Fig. 4 E is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges the equivalent electric circuit to each mode of operation of direct current transducer, and wherein step-up/step-down circuit and direction flyback converter all operate in the discontinuous current pattern;
Fig. 5 A to Fig. 5 B is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges the theoretical waveform to direct current transducer, and wherein step-up/step-down circuit and direction flyback converter all operate in the discontinuous current pattern;
Fig. 6 A to Fig. 6 C is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges the equivalent electric circuit to each mode of operation of direct current transducer, wherein work as step-up/step-down circuit and operate in the discontinuous current pattern, direction flyback converter operates under the continuous current pattern;
Fig. 7 is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges the theoretical waveform to direct current transducer, wherein works as step-up/step-down circuit and operates in the discontinuous current pattern, and direction flyback converter operates under the continuous current pattern;
Fig. 8 A to Fig. 8 B is for the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges another embodiment to direct current transducer;
Fig. 9 A to Fig. 9 B is for the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges another embodiment to direct current transducer;
Figure 10 is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges another embodiment to direct current transducer;
Figure 11 A to Figure 11 E is the equivalent electric circuit of the single-stage high-power-factor isolated form interchange of the disclosed tool leakage inductance energy of the present invention loop back function to each mode of operation of another embodiment of direct current transducer, and wherein the inductance of step-up/step-down circuit is operated in the discontinuous current pattern;
Figure 12 A to Figure 12 B is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges the theoretical waveform to another embodiment of direct current transducer, and wherein the inductance of step-up/step-down circuit is operated in the discontinuous current pattern;
Figure 13 A to Figure 13 C is the equivalent electric circuit of the single-stage high-power-factor isolated form interchange of the disclosed tool leakage inductance energy of the present invention loop back function to each mode of operation of another embodiment of direct current transducer, and wherein step-up/step-down circuit operates in discontinuous current pattern forward converter and operates in the continuous current pattern;
Figure 14 is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges the theoretical waveform to another embodiment of direct current transducer, and wherein step-up/step-down circuit operates in discontinuous current pattern forward converter and operates in the continuous current pattern;
Figure 15 A to Figure 15 B is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges another embodiment to direct current transducer;
Figure 16 A to Figure 16 B is that the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges another embodiment to direct current transducer.
[primary clustering symbol description]
110................................. filter circuit
120................................. rectification circuit
130................................. step-up/step-down circuit
140................................. direction flyback converter
141................................. forward converter
210................................. filter circuit
220................................. rectification circuit
230................................. step-up/step-down circuit
240................................. output circuit
250................................. load
310................................. filter circuit
320................................. rectification circuit
330................................. step-up/step-down circuit
340................................. output circuit
350................................. load
Vac................................. AC power
Lf.................................... filter inductance
Cf................................... filter capacitor
Dr1................................. diode
Dr2................................. diode
Dr3................................. diode
Dr4................................. diode
S1................................... switch
S2................................... switch
Lb................................... inductance
Cdc................................. electric capacity
Do.................................. output rectifier
Do1................................ output rectifier
Do2................................ output rectifier
Co.................................. output capacitance
Lo.................................. outputting inductance
L1................................... inductance
C1................................... electric capacity
Cin.................................. input capacitance
Db.................................. rectifier
Cin.................................. input capacitance
Dx.................................. rectifier
Dy.................................. rectifier
Vrec.............................. input voltage
Irec................................. electric current
Vgs................................. cross-pressure
T..................................... transformer
Tb................................... transformer
Tf.................................... transformer
IL1.................................. inductive current
ILm1............................... inductive current
ILm2............................... inductive current
ILlk................................. inductive current
ILo.................................. inductive current
Lm1................................ magnetizing inductance
Lm2................................ magnetizing inductance
Llk.................................. transformer leakage inductance
Embodiment
Below in execution mode, be described in detail detailed features of the present invention and advantage; its content is enough to make any people who is familiar with correlation technique to understand technology contents of the present invention and implements according to this; and according to the disclosed content of this specification, claim protection range and accompanying drawing, any people who is familiar with correlation technique can understand purpose and the advantage that the present invention is correlated with easily.Following embodiment further describes viewpoint of the present invention, but non-to limit category of the present invention anyways.
Please refer to Fig. 3, for the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges direct current transducer, it is applied to the flyback transformer, to drive load 250.In an exemplary embodiment, it is made up of a filter circuit 210, rectification circuit 220, an input capacitance Cin, a step-up/step-down circuit 230, a switch S 1, a transformer Tb and an output circuit 240.In this embodiment, switch S 1, transformer Tb and output circuit 240 are formed direction flyback converter.
Wherein step-up/step-down circuit 230, use a power supply is boosted or step-down, this power supply, this embodiment be with AC power Vac earlier by filter circuit 210 filtering after again by the power supply after rectification circuit 220 rectifications.Step-up/step-down circuit 230 is made up of with rectifier Db an inductance L 1, a capacitor C 1, and wherein inductance L 1 is connected with capacitor C 1, rectifier Db with connect after inductance L 1 in parallel with capacitor C 1.Transformer Tb electrically connects with step-up/step-down circuit 230, boosts or the power supply of step-down in order to change this.Switch S 1 electrically connects with step-up/step-down circuit 230.Input capacitance Cin electrically connects with step-up/step-down circuit 230.Output circuit 240 is given load 250 in order to the power supply of exporting after this transformer Tb changes.Wherein when switch S 1 was ended, step-up/step-down circuit 230 provided an energy reverse-path, is recycled to input capacitance Cin with the energy in the leakage inductance that will store transformer Tb.The energy reverse-path then is to be formed by rectifier Db.Can use diode in one embodiment, certainly also can use after the process proper arrangements such as BJT, MOSFET, SCR to have the assembly of rectification function.
In addition, Lm1 and Lm2 are respectively the transformer primary side and the secondary side magnetizing inductance of direction flyback converter (Flyback).Llk is total leakage inductance (Leakage Inductor) that the transformer of direction flyback converter (Flyback) reflexes to primary side.
240 of output circuits by output rectifier (for example diode) Do for to form with output capacitance Co.Rectifier Do also can use after the process proper arrangements such as BJT, MOSFET, SCR to have the assembly of rectification function.
The disclosed interchange of the present invention combines step-up/step-down circuit direct current transducer with direction flyback converter, and the free-wheel rectifier (Free-Wheeling Rectifier) that utilizes step-up/step-down circuit energy reverse-path the most, be recycled to input capacitance for general diode (Free-Wheeling Diode) commonly used with the energy in the transformer leakage inductance that will be stored in direction flyback converter among this embodiment.In this way, needn't add other assembly again, and can reduce the use of switch, just can solve the leakage inductance problem of direction flyback converter transformer, and then promote circuit efficiency.In an embodiment with diode as exemplary illustration, certainly for example BJT, MOSFET, SCR also can be used as the selection of rectifier with other assembly.
Next will analyze single-stage high-power-factor isolated form flyback interchange proposed by the invention operation principle to direct current transducer.Because the purposes of filter inductance Lf, filter capacitor Cf in the filter circuit 210 only be the radio-frequency component of filtering transducer input current, the action of transducer is not had any impact, so when analysis, it is ignored.
In order to reach the purpose of merit, make the inductance L 1 of step-up/step-down circuit be operated in the discontinuous current pattern, and direction flyback converter is not limit by this, is operable under discontinuous current pattern or the continuous current pattern because of revising.When step-up/step-down circuit and direction flyback converter all operate under the discontinuous current pattern, in each high frequency period, according to the conducting state of power switch assembly and diode, circuit can be distinguished into four mode of operations.The equivalent electric circuit of each mode of operation such as Fig. 4 A figure to Fig. 4 E, theoretical waveform such as Fig. 5 A to Fig. 5 B.In order to simplify the circuit signal, in Fig. 4 A figure to Fig. 4 E,, therefore omitted illustrating of filter inductance Lf, filter capacitor Cf and diode Dr1, Dr2, Dr3, Dr4 with Vrec representative power supply behind over commutation.In addition, make things convenient for the label that has also omitted other in order to read, and the assembly that does not move as yet in each pattern is represented by dotted lines.Specification after this reaches, Vgs represents the cross-pressure of switch S 1.The electric current of Irec representative behind over commutation.
(1) mode of operation I (switch S 1 conducting):
When switch S 1 conducting, the input voltage Vrec after the rectification on inductance L 1, inductive current iL1 linear the increasing of starting from scratch, the speed that current i L1 increases is directly proportional with input voltage Vrec.Simultaneously, the voltage on the capacitor C 1 of step-up/step-down circuit on the magnetizing inductance Lm1 of the primary side of transformer Tb, primary side inductive current iLm1 linear the increasing of also starting from scratch.At this moment, inductive current iL1 and the inductive current iLm1 switch S 1 of flowing through simultaneously.The moment that switch S 1 is ended, inductive current iL1 and inductive current iLm1 arrive the peak value in this cycle.
(2) mode of operation II (switch S 1 is ended):
End when switch S 1, inductance L 1 is kept current path, and the energy that will be stored in the inductance L 1 by rectifier Db is discharged into capacitor C 1, and inductive current iL1 begins to descend from peak value.Simultaneously, direction flyback converter also is coupled to Circuit Fault on Secondary Transformer with energy, and energy is discharged to output capacitance Co, and the secondary side inductive current iLm2 after the coupling also begins to descend from peak value.In addition, also can be recycled to input capacitance Cin this moment by the energy that rectifier Db will be stored in the transformer leakage inductance Llk of direction flyback converter.
Because this moment, step-up/step-down circuit and direction flyback converter all operated in the discontinuous current pattern, the peak value and the input voltage of adding inductive current iL1 are proportional, so inductive current iL1 may drop to zero than inductive current iLm2 is early; Also may drop to zero than inductive current iLm2 is late.Inductive current iL1 does not drop to zero yet when inductive current iLm2 drops to zero, enters mode of operation III-a; And inductive current iLm2 does not drop to zero yet when inductive current iL1 drops to zero, then enters mode of operation III-b.
(3) mode of operation III-a (when input voltage is higher):
At mode of operation III-a, inductive current iLm2 drops to zero when mode of operation II, and inductive current iL1 continues to descend, because inductance L 1 is operated in the discontinuous current pattern, therefore, in switch S 1 once more before the conducting, inductive current iL1 can be decremented to zero earlier, promptly enters mode of operation IV this moment.
(4) mode of operation III-b (when input voltage is low):
Because inductive current iL1 has dropped to zero when mode of operation II, and design Lm2 also is operated in the discontinuous current pattern, so the time only remaining inductive current iLm2 continue to descend, in case inductive current iLm2 also drops to zero, promptly enter mode of operation IV.
(5) mode of operation IV:
This moment, inductance L 1 and inductance L m1 did not have electric current to flow through, and only remaining output capacitance Co provides energy to load 250.When switch S 1 conducting once more, circuit promptly repeats the action situation of mode of operation I.
When step-up/step-down circuit operates in the discontinuous current pattern, direction flyback converter operates under the continuous current pattern, and in each high frequency period, according to the conducting state of power switch assembly and diode, circuit can be divided into three mode of operations.The equivalent electric circuit of each mode of operation such as Fig. 6 A to Fig. 6 C, theoretical waveform such as Fig. 7.
(1) mode of operation I (switch S 1 conducting):
When switch S 1 conducting, the input voltage Vrec after the rectification on inductance L 1, inductive current iL1 linear the increasing of starting from scratch, the speed that inductive current iL1 increases is directly proportional with input voltage.Simultaneously, the voltage on the capacitor C 1 of step-up/step-down circuit is on the magnetizing inductance Lm1 of the transformer Tb primary side of direction flyback converter, and primary side inductive current iLm1 also begins linear increasing.At this moment, inductive current iL1 and the inductive current iLm1 switch S 1 of flowing through simultaneously.The moment that switch S 1 is ended, inductive current iL1 and inductive current iLm1 arrive the peak value in this cycle.
(2) mode of operation II (switch S 1 is ended):
End when switch S 1, inductance L 1 is kept current path, and the energy that will be stored in the inductance L 1 by rectifier Db is discharged into capacitor C 1, and inductive current iL1 begins to descend from peak value.Simultaneously, direction flyback converter also is coupled to energy the secondary side of transformer Tb, and energy is discharged to output capacitance Co, and the secondary side inductive current iLm2 after the coupling also begins to descend.In addition, also can be recycled to input capacitance Cin this moment by the energy that rectifier Db will be stored in the transformer leakage inductance of direction flyback converter.Because this moment, step-up/step-down circuit operated in the discontinuous current pattern, direction flyback converter operates in the continuous current pattern, therefore has only inductive current iL1 can drop to zero.When inductive current iL1 drops to zero, enter mode of operation III.
(3) mode of operation III (inductive current iL1 drops to zero back):
Because inductive current iL1 has dropped to zero when mode of operation II, this moment, inductive current iLm2 continued to descend, and when switch S 1 conducting once more, circuit promptly repeats the action situation of mode of operation I.
As with the step-up/step-down circuit design operation in the discontinuous current pattern, then no matter direction flyback converter operates in discontinuous current pattern or continuous current pattern, the original desired circuit function of neither influence (merit is because of correction, electrical isolation, adjustment voltage quasi position ... or the like).In addition, the leakage inductance Llk of transformer in theory can be much smaller than the magnetizing inductance of transformer, so leakage inductance Llk goes up stored energy and can be discharged into input capacitance Cin in a short period of time.In a specific embodiment, be greater than 1/4th leakage inductance Llk and input capacitance Cin harmonic period the deadline of switch S 1, just can guarantee that the energy on the leakage inductance Llk can be sent input capacitance Cin fully back to.
In an embodiment of the present invention, in order to reach the function of merit because of revising, design inductance L 1 operates in the discontinuous current pattern, when the responsibility cycle (Duty Ratio) of switch less than 50% the time, the voltage on the capacitor C 1 can be lower than input voltage.After switch ends, because design inductance L 1 operates in the discontinuous current pattern, so inductive current iL1 can reduce to zero before the conducting once more in switch S 1.In case the voltage on the capacitor C 1 is greater than the peak value of input voltage, then VC1-Vin can make inductive current iL1 become negative value oppositely on inductance L 1, may cause circuit operation undesired like this.If this situation of generation is arranged, can be in rectifier Dx of either side serial connection of inductance L 1, for example the reverse possibility of inductive current iL1 shown in Fig. 8 A to Fig. 8 B, takes place to block in diode.
If design direction flyback converter (Flyback) operates in the discontinuous current pattern, because peak value and the input voltage of inductive current iL1 are proportional, so inductive current iL1 may drop to zero than inductive current iLlk is early; Also may drop to zero than inductive current iLlk is late.When inductive current iLlk just drops to zero than inductive current iL1 is early, this moment flow through rectifier Db and of inductive current iL1 to capacitor C 1 charging.In case rectifier Db conducting, the input voltage Vrec on the input capacitance Cin (input voltage after the rectification) can make inductive current iLm1 become negative value oppositely across the primary side of transformer Tb, may cause circuit operation undesired like this.This situation takes place if having, can be in rectifier Dy of either side serial connection of the both sides of the primary side of transformer Tb, for example diode shown in Fig. 9 A to Fig. 9 B, blocks the reverse possibility of inductive current iLm1 takes place.Fig. 8 A to Fig. 8 B is connected in series rectifier Dy respectively with Fig. 9 A to Fig. 9 B, also can all be connected in series a rectifier simultaneously with the either side of the both sides of the primary side of transformer Tb at the either side of inductance L 1 in another embodiment.
Please refer to Figure 10, for the single-stage high-power-factor isolated form of the disclosed tool leakage inductance energy of the present invention loop back function exchanges direct current transducer, it is to be applied to the forward type transformer, to drive load 350.In an exemplary embodiment, it is to be made up of a filter circuit 310, rectification circuit 320, an input capacitance Cin, a step-up/step-down circuit 330, a transformer Tf and an output circuit 340.In this embodiment, switch S 1, transformer Tf and output circuit 340 are formed forward converter.
Wherein step-up/step-down circuit 330, use a power supply is boosted or step-down, this power supply, this embodiment be with AC power Vac earlier by filter circuit 310 filtering after again by the power supply after rectification circuit 320 rectifications.Step-up/step-down circuit 330 is to be made up of an inductance L 1 and a capacitor C 1.Transformer Tf electrically connects with step-up/step-down circuit, boosts or the power supply of step-down in order to change this.Switch S 1 electrically connects with step-up/step-down circuit 330.Input capacitance Cin electrically connects with this step-up/step-down circuit.Output circuit 340 is in order to export the power supply after this transformer Tf changes.Wherein when switch S 1 was ended, step-up/step-down circuit 330 provided an energy reverse-path, is recycled to input capacitance Cin with the energy in the leakage inductance that will store transformer Tb.The energy reverse-path then is to be formed by rectifier Db.Can use diode in one embodiment, certainly also can use after the process proper arrangements such as BJT, MOSFET, SCR to have the assembly of rectification function.
Filter circuit 310 is to be made up of filter inductance Lf and filter capacitor Cf, is the radio-frequency component that is used for eliminating the transducer input current, makes input current be the low-frequency sine identical with input voltage phase.
Rectification circuit 320 is to be made up of at least more than one rectifier.Be to form a full bridge rectifier in this embodiment, also can use the rectification circuit of other form certainly by diode Dr1～Dr4.Except diode, can also use other for example assemblies such as BJT, MOSFET, SCR form rectification circuit.
In addition, Lm1 and Lm2 are respectively the transformer primary side and the secondary side magnetizing inductance of forward converter (Forward).Llk is total leakage inductance (Leakage Inductor) that the transformer of forward converter (Forward) reflexes to primary side.
340 output rectifiers of output circuit (for example diode) Do1, Do2, outputting inductance Lo and output capacitance Co form.Output rectifier Do also can use after the process proper arrangements such as BJT, MOSFET, SCR to have the assembly of rectification function.
Next will analyze single-stage high-power-factor isolated form forward type interchange proposed by the invention operation principle to direct current transducer.Because the purposes of filter inductance Lf, filter capacitor Cf in the filter circuit 310 does not only have any impact for the action to transducer of the radio-frequency component of filtering transducer input current, so when analysis it is ignored.
In order to reach the purpose of merit because of revising, in the discontinuous current pattern, and forward converter is not limit by this, is operable under discontinuous current pattern or the continuous current pattern with inductance L 1 design work of step-up/step-down circuit.When step-up/step-down circuit and forward converter all operated in the discontinuous current pattern, in each high frequency period, according to the conducting state of power switch assembly and diode, circuit can be distinguished into four mode of operations.The equivalent electric circuit of each mode of operation such as Figure 11 A to Figure 11 E, theoretical waveform such as Figure 12 A to Figure 12 B.
(1) mode of operation I (S1 conducting):
When switch S 1 conducting, the input voltage after the rectification on inductance L 1, inductive current iL1 linear the increasing of starting from scratch, the speed that inductive current iL1 increases is directly proportional with the Vrec input voltage.Simultaneously, the voltage on the step-up/step-down circuit capacitor C 1 and is coupled to energy the outputting inductance Lo and the capacitor C o of the transformer Tf secondary side of forward converter on the magnetizing inductance Lm1 of the transformer Tf primary side of forward converter.Inductive current iLo linear the increasing of also starting from scratch, inductive current iLm1 is along with one of the transformer induction electric current (according to the transformer turn ratio example) with inductive current iLo direct ratio simultaneously.At this moment, inductive current iL1 and the inductive current iLm1 switch S 1 of flowing through simultaneously.The moment that switch S 1 is ended, inductive current iL1 and inductive current iLo (inductive current iLm1) arrive the peak value in this cycle.
(2) mode of operation II (S1 ends):
End when switch S 1, inductance L 1 is kept current path, and the energy that will be stored in the inductance L 1 by rectifier Db is discharged into capacitor C 1, and inductive current iL1 begins to descend from peak value.Simultaneously, outputting inductance Lo transfers the energy to output capacitance Co by output rectifier Do2, and inductive current iLo also begins to descend from peak value.In addition, also can carry out demagnetizing action to the transformer Tf of forward converter by rectifier Db this moment, and energy is recycled to input capacitance Cin.Because this moment, step-up/step-down circuit and forward converter all worked in the discontinuous current pattern, the peak value and the input voltage of adding inductive current iL1 are proportional, so inductive current iL1 may drop to zero than inductive current iLo is early; Also may drop to zero than inductive current iLo is late.Inductive current iL1 does not drop to zero yet when inductive current iLo drops to zero, enters mode of operation III-a; And inductive current iLm2 does not drop to zero yet when inductive current iLo drops to zero, then enters mode of operation III-b.
(3) mode of operation III-a (when input voltage is higher):
At mode of operation III-a, inductive current iLo drops to zero when mode of operation II, and inductive current iL1 continues to descend, because inductance L 1 is operated in the discontinuous current pattern, therefore, in switch S 1 once more before the conducting, inductive current iL1 can be decremented to zero earlier, promptly enters mode of operation IV this moment.
(4) mode of operation III-b (when input voltage is low):
Because inductive current iL1 has dropped to zero when mode of operation II, and design inductance L o also is operated in the discontinuous current pattern, so the time only remaining inductive current iLo continue to descend, in case inductive current iLo also drops to zero, promptly enter mode of operation IV.
(5) mode of operation IV:
This moment, inductance L 1 and outputting inductance Lo did not have electric current to flow through, and only remaining output capacitance Co provides energy to load.When switch S 1 conducting once more, circuit promptly repeats the action situation of mode of operation I.
When step-up/step-down circuit operates in the discontinuous current pattern, when forward converter operated in the continuous current pattern, in each high frequency period, according to the conducting state of power switch assembly and diode, circuit can be divided into three mode of operations.The equivalent electric circuit of each mode of operation such as Figure 13 A to Figure 13 C, theoretical waveform such as Figure 14.
(1) mode of operation I (S1 conducting):
When switch S 1 conducting, the input voltage after the rectification on inductance L 1, inductive current iL1 linear the increasing of starting from scratch, the speed that inductive current iL1 increases is directly proportional with input voltage Vrec.Simultaneously, the voltage on the step-up/step-down circuit capacitor C 1 and is coupled to energy the outputting inductance Lo and the capacitor C o of forward converter secondary side on the magnetizing inductance Lm1 of forward converter transformer primary side.Inductive current iLo also begins linear increasing, and inductive current iLm1 is along with one of the transformer induction electric current (according to the transformer turn ratio example) with inductive current iLo direct ratio simultaneously.At this moment, inductive current iL1 and the inductive current iLm1 switch S 1 of flowing through simultaneously.The moment that switch S 1 is ended, inductive current iL1 and inductive current iLo (inductive current iLm1) arrive the peak value in this cycle.
(2) mode of operation II (S1 ends):
End when switch S 1, inductance L 1 is kept current path, and the energy that will be stored in the inductance L 1 by rectifier Db is discharged into capacitor C 1, and inductive current iL1 begins to descend from peak value.Simultaneously, outputting inductance Lo transfers the energy to output capacitance Co by output rectifier Do2, and inductive current iLo also begins to descend from peak value.In addition, also can carry out demagnetizing action to the transformer Tf of forward converter by rectifier Db this moment, and energy is recycled to input capacitance Cin.Because this moment, step-up/step-down circuit operated in the discontinuous current pattern, and forward converter operates in the continuous current pattern, therefore have only inductive current iL1 can drop to zero.When inductive current iL1 drops to zero, enter mode of operation III.
(3) mode of operation III (iL1 drops to zero back):
Because inductive current iL1 has dropped to zero when mode of operation II, this moment, inductive current iLo continued to descend, and when switch S 1 conducting once more, circuit promptly repeats the action situation of mode of operation I.
As with the step-up/step-down circuit design operation in the discontinuous current pattern, then no matter forward converter operates in discontinuous current pattern or continuous current pattern, the original desired circuit function of neither influence (merit is because of correction, electrical isolation, adjustment voltage quasi position ... or the like).In addition, the leakage inductance Llk of transformer in theory can be much smaller than the magnetizing inductance of transformer, so Llk goes up stored energy and can be discharged into Cin in a short period of time.At a specific embodiment, be greater than 1/4th Llk and Cin harmonic period the deadline of switch S 1, in order to do making the energy on the Llk can send input capacitance Cin fully back to.
In an embodiment of the present invention, in order to reach the function of merit because of revising, design L1 operates in the discontinuous current pattern, when the responsibility cycle (Duty Ratio) of switch less than 50% the time, the voltage on the capacitor C 1 can be lower than input voltage.After switch ends, because design inductance L 1 operates in the discontinuous current pattern, so iL1 can reduce to zero before the conducting once more at switch.In case the voltage on the capacitor C 1 is greater than the peak value of input voltage, then VC1-Vin can make IL1 become negative value oppositely on L1, may cause circuit operation undesired like this.If this situation of generation is arranged, can be in rectifier Dx of either side serial connection of inductance L 1, for example the reverse possibility of inductive current iL1 shown in Figure 15 A to Figure 15 B, takes place to block in diode.
In an embodiment of the present invention, because peak value and the input voltage of iL1 are proportional, so iL1 may drop to zero than iLlk is early; Also may drop to zero than iLlk is late.When iLlk just drops to zero than iL1 is early, this moment flow through Db and of iL1 to capacitor C 1 charging.In case rectifier Db conducting, the voltage Vrec on the input capacitance Cin (input voltage after the rectification) can make iLM1 become negative value oppositely across the transformer primary side, may cause circuit operation undesired like this.This situation takes place if having, can be in rectifier Dy of either side serial connection of the both sides of the primary side of transformer Tf, for example diode shown in Figure 16 A to Figure 16 B, blocks the reverse possibility of inductive current iLM1 takes place.Be connected in series rectifier Dy respectively among the embodiment of Figure 15 A to Figure 15 B and Figure 16 A to Figure 16 B, also can all be connected in series a rectifier simultaneously with the either side of the both sides of the primary side of transformer Tf in another embodiment at the either side of inductance L 1.
In another embodiment, as the embodiment among Fig. 3 that the inductance L 1 of step-up/step-down circuit is shared unshakable in one's determination with the transformer Tf of direction flyback converter, can reduce by a magnet assembly again, further reduce cost.
In another embodiment, as the embodiment among Figure 10, the inductance L 1 of step-up/step-down circuit is shared unshakable in one's determination with the outputting inductance Lo of forward converter, or the inductance L 1 of step-up/step-down circuit is shared unshakable in one's determination with the transformer Tf of forward converter, to reduce by a magnet assembly again, further reduce cost.
Therefore, the present invention combines step-up/step-down circuit with direction flyback converter or forward converter, and by assembly arrangement cleverly, utilize the energy that defeated diode (Free-Wheeling Diode) will be stored in the transformer leakage inductance of direction flyback converter that flies of step-up/step-down circuit to be recycled to input capacitance, in this way, needn't add other assembly again, just can solve the leakage inductance problem of direction flyback converter transformer, and then promote circuit efficiency; Utilize the transformer demagnetization path that defeated diode (Free-Wheeling Diode) provides forward converter that flies of step-up/step-down circuit, energy is recycled to input capacitance, in this way, needn't add other assembly and demagnetization winding (or claiming the demagnetization winding) again, just can solve the forward converter transformer and need add the demagnetization winding problem of (or claiming the demagnetization winding), and then promote the saving cost, reduce design difficulty and promote circuit efficiency
The single-stage high-power-factor isolated form that the present invention proposes exchanges direct current transducer, only need the switch S 1 of one group of control circuit and an active power, control mode is simple and be easy to realize, almost applicable to all transducer control modes, can pass through pulse wave width modulation (Pulse Width Modulation, PWM), frequency modulating (Pulse Frequency Modulation, PFM), magnetic hysteresis control (Hysteretic Control), fixing conduction and cut-off time (Constant On/Off Time) ... or the like mode control power output, control circuit is simple and be easy to realize.The inductance of step-up/step-down circuit is worked under the discontinuous current pattern, can make power factor near one; The inductance of step-up/step-down circuit is worked under the continuous current pattern, also can reach the effect of merit, but, therefore only mention the analysis of discontinuous current pattern here owing to operate in necessary adding the under the continuous current pattern than complicated control because of revising.In addition, and design suitable flyback or forward type transformer can be passed through, electrical isolation can be reached to meet the function of safety, the output of many windings and adjustment voltage quasi position.The complexity of not only simplifying circuit also promotes efficient, more reduces cost, and makes this transducer more competitive.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
Claims (14)
1. the single-stage high-power-factor isolated form of a tool leakage inductance energy loop back function exchanges direct current transducer, it is characterized in that, includes:
One step-up/step-down circuit is used a power supply is boosted or step-down;
One input capacitance electrically connects with this step-up/step-down circuit;
One transformer electrically connects with this step-up/step-down circuit, boosts or the power supply of step-down in order to change this;
One switch electrically connects with this step-up/step-down circuit; And
One output circuit is in order to export the power supply after this transformer is changed;
Wherein when this switch ended, this step-up/step-down circuit provided an energy reverse-path, is recycled to this input capacitance with the energy in the leakage inductance that will store this transformer.
2. interchange as claimed in claim 1 is to direct current transducer, it is characterized in that, this step-up/step-down circuit comprises an inductance, an electric capacity and a rectifier, it is characterized in that, this inductance of this step-up/step-down circuit and this capacitances in series of this step-up/step-down circuit, this rectifier of this step-up/step-down circuit with connect after this inductance in parallel with this electric capacity.
3. interchange as claimed in claim 2 is characterized in that to direct current transducer when this switch ended, this rectifier of this step-up/step-down circuit formed this energy reverse-path.
4. interchange as claimed in claim 2 is characterized in that direct current transducer, also includes a rectifier, is connected in a side of this inductance of this step-up/step-down circuit.
5. interchange as claimed in claim 2 is characterized in that direct current transducer, also includes a rectifier, is connected in the primary side of this transformer.
6. interchange as claimed in claim 2 is characterized in that direct current transducer, also includes at least two rectifiers, is connected to a side of this inductance and this transformer of this step-up/step-down circuit.
7. interchange as claimed in claim 2 is characterized in that to direct current transducer the iron core of this inductance of this step-up/step-down circuit and the iron core of this transformer are shared.
8. interchange as claimed in claim 1 is characterized in that to direct current transducer this output circuit is made up of an output rectifier and an output capacitance.
9. interchange as claimed in claim 1 is characterized in that to direct current transducer this output circuit is made up of one or two output rectifier, an output capacitance and an outputting inductance.
10. interchange as claimed in claim 9 is characterized in that to direct current transducer the iron core of this inductance and the iron core of this outputting inductance are shared.
11. interchange as claimed in claim 1 is characterized in that direct current transducer, more includes a rectification circuit, electrically connects with this input capacitance, in order to this power supply is carried out rectification.
12. interchange as claimed in claim 11 is characterized in that to direct current transducer this rectifier includes at least more than one rectifier.
13. interchange as claimed in claim 11 is characterized in that direct current transducer, more includes a filter circuit, electrically connects with this rectification circuit.
14. interchange as claimed in claim 13 is characterized in that to direct current transducer this filter circuit is made up of a filter inductance and a filter capacitor.
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| CN2008101877814A CN101771346B (en) | 2008-12-31 | 2008-12-31 | Single-stage high power factor isolating type AC to DC converter with leakage inductance energy loopback function |
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| CN2008101877814A CN101771346B (en) | 2008-12-31 | 2008-12-31 | Single-stage high power factor isolating type AC to DC converter with leakage inductance energy loopback function |
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| CN102684492A (en) * | 2012-05-11 | 2012-09-19 | 杭州电子科技大学 | High power factor converter |
| CN104348361A (en) * | 2014-11-04 | 2015-02-11 | 无锡中星微电子有限公司 | Booster-buck converter |
| CN104578844A (en) * | 2014-12-22 | 2015-04-29 | 广州金升阳科技有限公司 | Switching mode power supply circuit |
| CN104852610A (en) * | 2015-05-15 | 2015-08-19 | 广州金升阳科技有限公司 | Leakage inductance energy recovery circuit and switching power supply based on circuit |
| CN106535402A (en) * | 2016-11-22 | 2017-03-22 | 福州大学 | Single-stage single-switch voltage-reducing type leakage inductor energy utilization LED driving circuit |
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| US5134355A (en) * | 1990-12-31 | 1992-07-28 | Texas Instruments Incorporated | Power factor correction control for switch-mode power converters |
| US6487098B2 (en) * | 2001-02-01 | 2002-11-26 | International Business Machines Corporation | Power factor correction (PFC) circuit that eliminates an inrush current limit circuit |
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| CN201146458Y (en) * | 2007-09-07 | 2008-11-05 | 马丽娟 | Non-bridge monopole insulation convertor with low noise |
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| CN102684492A (en) * | 2012-05-11 | 2012-09-19 | 杭州电子科技大学 | High power factor converter |
| CN104348361A (en) * | 2014-11-04 | 2015-02-11 | 无锡中星微电子有限公司 | Booster-buck converter |
| CN104348361B (en) * | 2014-11-04 | 2017-06-06 | 无锡中感微电子股份有限公司 | A kind of voltage raising and reducing converter |
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| CN104852610B (en) * | 2015-05-15 | 2018-03-06 | 广州金升阳科技有限公司 | Leakage inductance energy recovery circuit and the Switching Power Supply based on the circuit |
| CN107370380A (en) * | 2016-05-13 | 2017-11-21 | 亚力电机股份有限公司 | Buck-boost type direct current transducer |
| CN107370380B (en) * | 2016-05-13 | 2020-02-04 | 亚力电机股份有限公司 | Boost-buck type direct current converter |
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| TWI678873B (en) * | 2018-12-28 | 2019-12-01 | 遠東科技大學 | Interleaved dc-dc forward converter |
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