CN104319999A - Middle-high voltage variable frequency speed control circuit based on modular multilevel converter (MMC) - Google Patents
Middle-high voltage variable frequency speed control circuit based on modular multilevel converter (MMC) Download PDFInfo
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- CN104319999A CN104319999A CN201410572061.5A CN201410572061A CN104319999A CN 104319999 A CN104319999 A CN 104319999A CN 201410572061 A CN201410572061 A CN 201410572061A CN 104319999 A CN104319999 A CN 104319999A
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Inverter Devices (AREA)
Abstract
The invention relates to a middle-high voltage variable frequency speed control circuit based on a modular multilevel converter (MMC). The middle-high voltage variable frequency speed control circuit based on the MMC comprises a cascade rectifier circuit and a cascade inverter circuit, an input capacitor is connected with an output capacitor through a high-frequency isolated direct current/direct current (DC/DC) converter, the high-frequency isolated DC/DC converter comprises a primary side H bridge with four power switch devices, an output end of the primary side H bridge is connected with a primary side coil of a high-frequency transformer, a secondary side coil of the high-frequency transformer is connected with an input end of a secondary side H bridge, and an output end of the secondary side H bridge is in bridge joint with two ends of the output capacitor. According to the middle-high voltage variable frequency speed control circuit based on the MMC, a rectification section is isolated from an inversion end of an MMC variable-frequency speed control system by means of the high-frequency isolated DC/DC converter; energy transmission and feedback can be efficiently achieved without an industrial frequency transformer; the high-frequency isolated DC/DC converter is added so that a rectifier and an inverter can safely work without mutual influence, and safe and reliable work can be achieved while efficient energy transmission can be guaranteed.
Description
Technical field
The present invention relates to a kind of based on MMC(Modular Multilevel Converter) mesohigh frequency variant speed regulating circuit, being a kind of cascade MMC frequency converter with high-frequency isolation, is a kind of mesohigh frequency variant speed regulating circuit based on MMC.
Background technology
Along with science and technology and the fast development of the modernization of industry and the requirement to energy savings, the mesohigh electronic frequency convertor being applied to large-power occasions plays a part more and more important.Based on the application that the medium-high voltage frequency converter of electric power electric transformer (PET) has been succeeded in fields such as high-tension high-power frequency control, active electric filter device and power system reactive power compensations.In recent years, based on MMC mesohigh frequency conversion speed-adjusting system because of its harmonic pollution low, advantage that modular structure is simple and integrated level is high, and fault-tolerant ability is strong etc., becomes the study hotspot in frequency control field gradually.As a kind of New Cascading formula multi-level frequency conversion device, the topmost advantage of medium-high voltage frequency converter based on MMC is the restriction having broken away from Industrial Frequency Transformer, under the prerequisite reducing own vol, substantially increase the efficiency of transmission of energy, perfect power factor regulation and low harmony wave pollute and can make frequency converter that the whole energy absorbed from electrical network are passed to load with low-down loss.This for power transmission system especially in mine frequency conversion speed-adjusting system the realization of the high efficiency of transmission of energy conservation and energy provide realistic plan.
Although the mesohigh frequency conversion speed-adjusting system based on MMC obtains development to a certain degree, and himself Problems existing also requires further improvement.The rectification side existed for the frequency conversion speed-adjusting system back-to-back based on MMC and inverter side can not realize the problem of effectively isolating completely, during the accidents such as puncturing appears in any side, short circuit, capital has influence on opposite side, and even whole rectification, inversion system, make whole system all destroy.
Summary of the invention
In order to overcome the problem of prior art, the present invention proposes a kind of mesohigh frequency variant speed regulating circuit based on MMC.Described circuit can put forward high-octane transmission efficiency on the basis realizing rectification and inversion isolation, realizes frequency conversion speed-adjusting system and more efficiently, reliably runs.
The object of the present invention is achieved like this: a kind of mesohigh frequency variant speed regulating circuit based on MMC, comprise: the cascade rectifier circuit with multiple MMC unit be connected with three phase mains, the cascade inverter circuit with multiple MMC unit be connected with load, be connected in series in multiple output capacitances of cascade rectifier circuit two outputs, with the input capacitance being connected in series in cascade inverter circuit input two ends, by being connected with at least one high-frequency isolation DC/DC converter between described output capacitance and input capacitance, described high-frequency isolation DC/DC converter comprises: with the former limit H bridge of four device for power switching, the input of described former limit H bridge is connected across output capacitance two ends, the output of described former limit H bridge is connected with the primary coil of high frequency transformer, described high frequency transformer secondary coil is connected with the input of the secondary H bridge with four device for power switching, the output of described secondary H bridge is connected across the two ends of an input capacitance.
Further, described device for power switching is the one in MOSFET or IGBT.
The beneficial effect that the present invention produces is: the present invention adopts high-frequency isolation DC/DC converter by the rectification side of MMC frequency conversion speed-adjusting system and inverter side isolation.Using frequency converter of the present invention without the need to using phase shift Industrial Frequency Transformer, transmission and the feedback of energy can be realized efficiently.Owing to adding high-frequency isolation DC/DC converter in frequency conversion speed-adjusting system, rectifier and inverter can not affected by trouble free service each other.This frequency conversion speed-adjusting system can realize more safe and reliable work while ensureing energy high efficiency of transmission, thus make this kind based on the mesohigh frequency variant speed regulating circuit of MMC at high-power electric and electronic transformer, the applications such as high-power mesohigh ac-dc-ac inverter transmission there is important practical value.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described.
Fig. 1 is the theory diagram of circuit described in embodiments of the invention one;
Fig. 2 is the topology theory figure of circuit described in embodiments of the invention one.
Embodiment
Embodiment one:
The present embodiment is a kind of mesohigh frequency variant speed regulating circuit based on MMC, shown in Fig. 1,2.The present embodiment comprises: the cascade rectifier circuit with multiple MMC unit be connected with three phase mains, the cascade inverter circuit with multiple MMC unit be connected with load, be connected in series in multiple output capacitances of cascade rectifier circuit two outputs, with the input capacitance being connected in series in cascade inverter circuit input two ends, by being connected with at least one high-frequency isolation DC/DC converter between described output capacitance and input capacitance, described high-frequency isolation DC/DC converter comprises: with the former limit H bridge of four device for power switching, the input of described former limit H bridge is connected across output capacitance two ends, the output of described former limit H bridge is connected with the primary coil of high frequency transformer, described high frequency transformer secondary coil is connected with the input of the secondary H bridge with four device for power switching, the output of described secondary H bridge is connected across the two ends of an input capacitance.
Mesohigh frequency variant speed regulating circuit described in the present embodiment comprises three parts: cascade rectifier circuit, high-frequency isolation DC/DC converter and cascade inverter circuit, as shown in Figure 1.
Cascade rectifier circuit comprises MMC unit, three-phase input inductance, brachium pontis inductance, output capacitance.The effect of cascade rectifier circuit is direct current by the ac high-voltage rectification of three-phase input side.Each MMC unit comprises two device for power switching, two power switching device series, and the device for power switching after series connection is in parallel with storage capacitor thus form a MMC unit.The present embodiment is three phase mains input, and the MMC unit that each is in series is divided into upper and lower bridge arm two parts, and upper and lower bridge arm part connects together through two brachium pontis inductance.Every inductance of input mutually connects input power respectively and is connected mid point with brachium pontis inductance.Remaining two common ports of every phase MMC unit are connected in parallel composition one group of DC bus, and the two ends of DC bus are connected with output capacitance, the cascade rectifier that common composition three-phase star connects.The number of MMC unit is determined by three-phase input voltage.For three phase mains, at least should have six MMC unit, namely often in switching process, use two MMC unit, three-phase is then six.If frequency changer circuit will be used in higher voltage power supply occasion, more MMC unit of can connecting.The number of required MMC unit determines according to the voltage endurance capability of three-phase input voltage and each device for power switching.
The output capacitance that in the present embodiment, the two ends (comprising rectification side and inverter side) of DC bus are connected and input capacitance can be two single electric capacity, also can be the electric capacity of two string series connection.The number of series capacitance can be identical with high-frequency isolation DC/DC converter number, also can be different.Under normal conditions, if only have a high-frequency isolation DC/DC converter, then only can use an output capacitance and an input capacitance, if there are two high-frequency isolation DC/DC converters, need use two input capacitances and two output capacitances, the rest may be inferred by analogy.
High-frequency isolation DC/DC converter is the key of the present embodiment, comprising the H bridge (former limit H bridge and secondary H bridge), high frequency transformer etc. of two groups of symmetries.The effect of high-frequency isolation DC/DC converter is the isolation realizing rectification side and inverter side, by the energy transferring of rectification side to inverter side, prevent inverter side or rectification side there is accident and affects opposite side in either party simultaneously, avoids the diffusion of accident, ensures the safety of electrical network or load.
Each group H bridge comprises 4 powerful device for power switching.Device for power switching two one group is together in series and then is parallel to and forms H bridge together.High frequency transformer mainly plays buffer action, and what its former limit and secondary connect two groups of H bridges respectively exchanges end, composition high-frequency isolation DC/DC converter.Former limit H bridge is under the control of the triggering signal of device for power switching, the DC power conversion exported by rectification circuit is high-frequency alternating current, by the induction on the former and deputy limit of high frequency transformer, high-frequency alternating current is produced at secondary, again through secondary H bridge, under the triggering signal of the device for power switching of secondary H bridge controls, high-frequency alternating current is transformed to direct current.According to power transfer requirements, high-frequency isolation DC/DC converter can be used alone, and also several parallel connections can use, realizes the high efficiency of transmission of energy.
Powerful device for power switching described in the present embodiment refers to that rated power is at thousands of watts, or the device for power switching of tens of kilowatt.These device for power switching in MMC and H bridge can be various forms of device for power switching, such as: MOSFET or IGBT, and other corresponding devices.
The advantage of high-frequency isolation DC/DC converter that set of power switches becomes is: the triggering signal of change device for power switching, can the transmitted in both directions of energy in control circuit.The present embodiment also make use of this advantage of high-frequency isolation DC/DC converter just.Use in tradition in the frequency conversion speed-adjusting system of Industrial Frequency Transformer, the volume of Industrial Frequency Transformer and cost are very large.Reason is very simple, and under power frequency, transmit larger power, just need the Industrial Frequency Transformer of larger volume, the Industrial Frequency Transformer of larger volume means the increase of cost.And the present embodiment utilizes high-frequency isolation DC/DC converter to replace traditional Industrial Frequency Transformer, under the prerequisite improving energy transmission efficiency, decrease the volume of circuit, reduce the cost of manufacture of circuit.
As increased MMC modular unit in frequency variant speed regulating circuit, the number of high-frequency isolation DC/DC converter determines primarily of the power (cost) of the power of whole load and the device for power switching of use.Multiple high-frequency isolation DC/DC converter in parallel, can make the rated power of inverter be multiplied.
The no-load voltage ratio of high frequency transformer can be chosen as 1:1, also can be chosen as other no-load voltage ratio.The selection of no-load voltage ratio is carried out according to the needs of concrete occasion completely.No-load voltage ratio can be selected as a rule to be 1:1, the adjustment carrying out energy turnover direction that like this can be random.And under the occasion that some are special, such as, need to optimize certain parameter, such as power, electric current, power factor etc., then can by selecting suitable no-load voltage ratio, and coordinate suitable control strategy to realize above-mentioned purpose.
Cascade inverter circuit comprises input capacitance, MMC unit, brachium pontis inductance and load.The effect of cascade inverter circuit is the voltage inversion obtained by DC/DC converter is that three-phase alternating current is for load.Similar with cascade rectifier circuit, each MMC unit of cascaded inverter comprises two high-power MOSFETs or IGBT(device for power switching equally), two power switching device series, the device for power switching after series connection is in parallel with storage capacitor thus form a MMC modular unit.Two common ports of every phase MMC unit are connected in parallel composition one group of DC bus, and the two ends of DC bus are connected with output capacitance.Each MMC unit that is in series is divided into upper and lower bridge arm two parts, and upper and lower bridge arm part connects together through two brachium pontis inductance.Brachium pontis inductance connects mid point and is connected with load, composition cascade multi-level inverter circuit.
The number of the MMC unit in cascade inverter circuit can be identical with the MMC unit number in cascade rectifier circuit, also can not be identical.The main rated power of whole frequency variant speed regulating circuit according to load, the cost of device for power switching consider, and determine the number of MMC modular unit.
Due in the present embodiment, for input and output, circuit is all full symmetric, therefore, input and the output of the present embodiment are relative, as long as change the control mode of converter circuit, input can become output, and output then becomes input.Such circuit has an advantage, namely in some cases .., can exchange by fulfillment capability.Such as: the present embodiment is applied in the occasion of the generator-pump motor at pumped-storage power generation station, just can play great effect.In the process of pumped storage, load (pump motor) uses the electrical energy drive water pump of electrical network; Just contrary when utilizing the generating power by water current in cistern, pump motor has become generator, export energy, and the one end of originally drawing power grid energy becomes load end.And use the rectification of the present embodiment, isolation and inverter circuit, its hardware need not change completely, also without the need to using the means such as back brake, only need change the triggering signal control mode of each MMC unit and each device for power switching of high-frequency isolation DC/DC converter, the flow direction of change energy that just can be random.If each MMC unit and each device for power switching of high-frequency isolation DC/DC converter, employ the digital processing unit with stored digital and computing function to control the triggering signal that each controllable part carries out device for power switching, then in the control of energy position, only need change the software in digital processing unit, achieve soft power supply control.
Embodiment two:
The present embodiment is the improvement of embodiment one, is the refinement of embodiment one about device for power switching.Device for power switching described in the present embodiment is the one in MOSFET or IGBT.
Finally it should be noted that, below only in order to technical scheme of the present invention to be described and unrestricted, although with reference to preferred arrangement scheme to invention has been detailed description, those of ordinary skill in the art is to be understood that, can modify to technical scheme of the present invention (connected mode of such as whole circuit, the connected mode etc. of MMC and H bridge) or equivalent replacement, and not depart from the spirit and scope of technical solution of the present invention.
Claims (2)
1. the mesohigh frequency variant speed regulating circuit based on MMC, comprise: the cascade rectifier circuit with multiple MMC unit be connected with three phase mains, the cascade inverter circuit with multiple MMC unit be connected with load, be connected in series in multiple output capacitances of cascade rectifier circuit two outputs, with the input capacitance being connected in series in cascade inverter circuit input two ends, it is characterized in that, by being connected with at least one high-frequency isolation DC/DC converter between described output capacitance and input capacitance, described high-frequency isolation DC/DC converter comprises: with the former limit H bridge of four device for power switching, the input of described former limit H bridge is connected across output capacitance two ends, the output of described former limit H bridge is connected with the primary coil of high frequency transformer, described high frequency transformer secondary coil is connected with the input of the secondary H bridge with four device for power switching, the output of described secondary H bridge is connected across the two ends of an input capacitance.
2. mesohigh frequency variant speed regulating circuit according to claim 1, is characterized in that, described device for power switching is the one in MOSFET or IGBT.
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| CN201410572061.5A CN104319999A (en) | 2014-10-24 | 2014-10-24 | Middle-high voltage variable frequency speed control circuit based on modular multilevel converter (MMC) |
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| CN201410572061.5A CN104319999A (en) | 2014-10-24 | 2014-10-24 | Middle-high voltage variable frequency speed control circuit based on modular multilevel converter (MMC) |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104836456A (en) * | 2015-05-26 | 2015-08-12 | 苏州优电电气技术有限公司 | Power electron transformer topology composition based on cascade multilevel |
| CN105515401A (en) * | 2015-11-30 | 2016-04-20 | 武汉大学 | Solid state transformer in modularized multi-level structure |
| CN107769586A (en) * | 2017-11-10 | 2018-03-06 | 珠海万力达电气自动化有限公司 | A kind of single-phase three-phase inversion power supply |
| CN108146297A (en) * | 2017-12-30 | 2018-06-12 | 中铁第四勘察设计院集团有限公司 | A kind of electric railway ground electricity split-phase uninterruptible power supply system |
| CN108306520A (en) * | 2017-12-30 | 2018-07-20 | 中国船舶重工集团公司第七〇二研究所 | A kind of converter plant of electric railway ground automatic neutral-section passing system |
| CN110492748A (en) * | 2019-06-24 | 2019-11-22 | 华北电力大学 | A kind of reciprocating isolated form DC/DC converter topology of output based on DAB |
| CN111641344A (en) * | 2020-05-27 | 2020-09-08 | 南京航空航天大学 | Modular multilevel converter submodule capacitor energy recovery and pre-charging integrated device |
-
2014
- 2014-10-24 CN CN201410572061.5A patent/CN104319999A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104836456A (en) * | 2015-05-26 | 2015-08-12 | 苏州优电电气技术有限公司 | Power electron transformer topology composition based on cascade multilevel |
| CN105515401A (en) * | 2015-11-30 | 2016-04-20 | 武汉大学 | Solid state transformer in modularized multi-level structure |
| CN107769586A (en) * | 2017-11-10 | 2018-03-06 | 珠海万力达电气自动化有限公司 | A kind of single-phase three-phase inversion power supply |
| CN108146297A (en) * | 2017-12-30 | 2018-06-12 | 中铁第四勘察设计院集团有限公司 | A kind of electric railway ground electricity split-phase uninterruptible power supply system |
| CN108306520A (en) * | 2017-12-30 | 2018-07-20 | 中国船舶重工集团公司第七〇二研究所 | A kind of converter plant of electric railway ground automatic neutral-section passing system |
| CN110492748A (en) * | 2019-06-24 | 2019-11-22 | 华北电力大学 | A kind of reciprocating isolated form DC/DC converter topology of output based on DAB |
| CN111641344A (en) * | 2020-05-27 | 2020-09-08 | 南京航空航天大学 | Modular multilevel converter submodule capacitor energy recovery and pre-charging integrated device |
| CN111641344B (en) * | 2020-05-27 | 2022-06-10 | 南京航空航天大学 | Modular multi-level converter submodule capacitor energy recovery and pre-charging integrated device |
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Application publication date: 20150128 |