CN114070032A - Vehicle, vehicle-mounted charging system and control method of PFC circuit in vehicle-mounted charging system - Google Patents

Vehicle, vehicle-mounted charging system and control method of PFC circuit in vehicle-mounted charging system Download PDF

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Publication number
CN114070032A
CN114070032A CN202010779205.XA CN202010779205A CN114070032A CN 114070032 A CN114070032 A CN 114070032A CN 202010779205 A CN202010779205 A CN 202010779205A CN 114070032 A CN114070032 A CN 114070032A
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voltage
switching tube
tube
switch tube
switched
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Chinese (zh)
Inventor
王超
莫旭杰
王兴辉
李武杰
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BYD Co Ltd
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BYD Co Ltd
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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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4233—Arrangements for improving power factor of AC input using a bridge converter comprising active switches
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/20—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by converters located in the vehicle
    • 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
    • H02M3/325—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 using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—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 using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/3353—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 using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The invention discloses a vehicle, a vehicle-mounted charging system and a control method of a PFC circuit in the vehicle-mounted charging system, wherein the PFC circuit comprises at least one phase high-frequency bridge arm, the high-frequency bridge arm comprises a first switching tube, a second switching tube and a first capacitor, the first capacitor is connected with the first switching tube in parallel, and the control method comprises the following steps: when the first switch tube is controlled to be conducted and the second switch tube is controlled to be closed, first voltage parameter information of two ends of the first capacitor is obtained; judging whether the first switching tube is conducted at zero voltage or not according to the first voltage parameter information; when the first switch tube is not switched on at zero voltage, the first switching-on duration of the second switch tube is increased according to a preset rule so as to reduce the voltage when the first switch tube is switched on again. The method can realize zero-voltage conduction of the high-frequency switching tube in the PFC circuit, reduce the turn-on loss and turn-off loss of the high-frequency switching tube, and is beneficial to improving the working efficiency of the vehicle-mounted charging system.

Description

Vehicle, vehicle-mounted charging system and control method of PFC circuit in vehicle-mounted charging system
Technical Field
The invention relates to the technical field of vehicles, in particular to a control method of a PFC circuit in a vehicle-mounted charging system, the vehicle-mounted charging system and a vehicle.
Background
In the related art, the topology of the OBC (On Board Charger) generally adopts two stages, a front stage PFC (Power Factor Correction) stage and a rear stage DCDC stage. The PFC stage serves as a preceding stage AC/DC circuit of the OBC, and has a function of converting an AC voltage of a power grid into a stable DC voltage, and at present, the PFC circuit generally operates in a CCM (Continuous Conduction Mode) Mode, and the switching tube cannot implement zero-voltage Conduction.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, a first object of the present invention is to provide a method for controlling a PFC circuit in an in-vehicle charging system. The method can realize zero voltage conduction of the high-frequency switching tube in the PFC circuit, reduce the turn-on loss and the break loss of the high-frequency switching tube, and is beneficial to improving the working efficiency of the vehicle-mounted charging system.
The second purpose of the invention is to provide a vehicle-mounted charging system.
A third object of the invention is to propose a vehicle.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a control method for a PFC circuit in a vehicle-mounted charging system, where the PFC circuit includes at least one phase high-frequency leg, and the high-frequency leg includes a first switching tube, a second switching tube, and a first capacitor, and the first capacitor is connected in parallel with the first switching tube, and the control method includes: when the first switch tube is controlled to be switched on and the second switch tube is controlled to be switched off, first voltage parameter information of two ends of the first capacitor is obtained; judging whether the first switching tube is conducted at zero voltage or not according to the first voltage parameter information; and when the first switch tube is not switched on at zero voltage, increasing the first switching-on duration of the second switch tube according to a preset rule so as to reduce the voltage when the first switch tube is switched on again.
According to the control method of the PFC circuit in the vehicle-mounted charging system, disclosed by the embodiment of the invention, through software control, the soft switching of the PFC high-frequency switching tube can be realized, the zero-voltage conduction of the high-frequency switching tube in the PFC circuit can be realized, the turn-on loss and the break loss of the high-frequency switching tube are reduced, and the working efficiency of the vehicle-mounted charging system is favorably improved.
In order to achieve the above object, a second aspect of the present invention provides an onboard charging system, including: the PFC circuit comprises at least one phase high-frequency bridge arm, the high-frequency bridge arm comprises a first switching tube, a second switching tube and a first capacitor, and the first capacitor is connected with the first switching tube in parallel; a control module configured to: when the first switch tube is controlled to be switched on and the second switch tube is controlled to be switched off, first voltage parameter information of two ends of the first capacitor is obtained; judging whether the first switching tube is conducted at zero voltage or not according to the first voltage parameter information; and when the first switch tube is not switched on at zero voltage, increasing the first switching-on duration of the second switch tube according to a preset rule so as to reduce the voltage when the first switch tube is switched on again.
According to the vehicle-mounted charging system provided by the embodiment of the invention, through the control method of the PFC circuit in the vehicle-mounted charging system, the soft switching of each high-frequency switching tube of the PFC can be realized, the zero-voltage conduction of the high-frequency switching tube in the PFC circuit can be realized, the turn-on loss and the break loss of the high-frequency switching tube are reduced, and the working efficiency of the vehicle-mounted charging system is favorably improved.
In order to achieve the above object, a third embodiment of the present invention provides a vehicle including the above vehicle-mounted charging system.
According to the vehicle provided by the embodiment of the invention, through the vehicle-mounted charging system, the soft switching of each high-frequency switching tube of the PFC can be realized, the zero-voltage conduction of the high-frequency switching tube in the PFC circuit can be realized, the turn-on loss and the break loss of the high-frequency switching tube are reduced, and the work efficiency of the vehicle-mounted charging system is favorably improved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a topology diagram of an in-vehicle charging system according to one embodiment of the invention;
fig. 2 is a topology diagram of a PFC circuit according to one embodiment of the present invention;
fig. 3 is a flowchart of a control method of a PFC circuit in the vehicle charging system according to one embodiment of the present invention;
FIG. 4 is a soft switching schematic of CRM mode according to one embodiment of the invention;
fig. 5 is a schematic diagram of the operation of a PFC circuit according to a first example of the present invention;
fig. 6 is a schematic diagram of the operation of a second exemplary PFC circuit according to the present invention;
fig. 7 is an operational schematic diagram of a PFC circuit according to a third example of the present invention;
fig. 8 is an operational schematic diagram of a fourth exemplary PFC circuit according to the present invention;
fig. 9 is an operational schematic diagram of a fifth exemplary PFC circuit according to the present invention;
fig. 10 is a control schematic diagram of a PFC circuit in the vehicle-mounted charging system according to one specific example of the present invention;
fig. 11 is a block diagram of the structure of an in-vehicle charging system according to an embodiment of the invention;
fig. 12 is a block diagram of a vehicle according to an embodiment of the invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
A vehicle, an on-vehicle charging system, and a control method of a PFC circuit in the vehicle, an on-vehicle charging system, and a control method of a PFC circuit according to embodiments of the present invention are described below with reference to fig. 1 to 12.
In the embodiment of the present invention, as shown in fig. 1, the vehicle-mounted charging system includes a PFC circuit 21 and a bus capacitor C connected in sequenceiAnd a bi-directional DC/DC circuit 22. Referring to fig. 1 and 2, the PFC circuit 21 includes at least one inductor, at least one phase high-frequency bridge arm, and one phase power-frequency bridge arm, which are connected in sequence, where the inductors correspond to the high-frequency bridge arms one to one.
Referring to fig. 1, the PFC circuit 21 includes an inductor L1, a phase high-frequency bridge arm and a phase power-frequency bridge arm, which are connected in sequence, where the phase high-frequency bridge arm includes a first high-frequency switching tube P1 and a second high-frequency switching tube P2, the power-frequency bridge arm includes a first power-frequency switching tube P5 and a second power-frequency switching tube P6, and each switching tube is connected in parallel with a capacitor, which is respectively a capacitor C1, a capacitor C2, a capacitor C5, and a capacitor C6.
Referring to fig. 2, the PFC circuit 21 includes two inductors L1 and L2, a two-phase high-frequency bridge arm, and a one-phase power-frequency bridge arm, which are connected in sequence. The high-frequency bridge arm connected with the inductor L1 comprises a first high-frequency switching tube P1 and a second high-frequency switching tube P2; the high-frequency bridge arm connected with the inductor L2 comprises a first high-frequency switching tube P3 and a second high-frequency switching tube P4; the power frequency bridge arm comprises a first power frequency switch tube P5 and a second power frequency switch tube P6, wherein the switch tubes are connected in parallel with capacitors C1, C2, C3, C4, C5 and C6.
Of course, the number of inductors and the number of high-frequency bridge arms may also be 3, 4, etc. That is, in the embodiment of the present invention, the PFC circuit 21 may include a single-phase full bridge circuit as shown in fig. 1, and may further include an N-phase interleaved bridge circuit, where N is an integer greater than or equal to 2, for example, the two-phase interleaved bridge circuit as shown in fig. 2.
Fig. 3 is a flowchart of a control method of a PFC circuit in the vehicle charging system according to one embodiment of the present invention. As shown in fig. 3, the control method includes the steps of:
s101, when the first switch tube is controlled to be conducted and the second switch tube is controlled to be closed, first voltage parameter information of two ends of the first capacitor is obtained.
If the first switch tube is a first high-frequency switch tube, the second switch tube is a second high-frequency switch tube; if the first switch tube is the second high-frequency switch tube, the second switch tube is the first high-frequency switch tube. The following description will be made by taking as an example that the first switch is the high-frequency switch P2 in fig. 1 and 2 and the second switch is the high-frequency switch P1 in fig. 1 and 2, wherein the first switch is connected in parallel with a capacitor C2 (i.e., a first capacitor).
And S102, judging whether the first switch tube is conducted at zero voltage or not according to the first voltage parameter information.
S103, when the first switch tube is not conducted at zero voltage, the first conduction duration of the second switch tube is increased according to a preset rule so as to reduce the voltage when the first switch tube is conducted again.
Therefore, the control method can reduce the voltage when the first switching tube is conducted again by increasing the first conduction time of the second switching tube, and further can reduce the conduction loss of the first switching tube.
In one embodiment of the present invention, referring to fig. 1 and fig. 2, the second switch tube is connected in parallel with a capacitor C1 (i.e., a second capacitor); the control method may further include: after the first switching tube is controlled to be conducted and the second switching tube is controlled to be closed for a second conduction time, the first switching tube is controlled to be closed and the second switching tube is controlled to be closed; controlling the power frequency bridge arm to release the energy of the second capacitor within the first dead time, and controlling the first switching tube to be closed and the second switching tube to be conducted until the first dead time is reached; acquiring second voltage parameter information at two ends of a second capacitor; judging whether the second switching tube is conducted at zero voltage or not according to the second voltage parameter information; and when the second switching tube is not switched on at zero voltage, increasing the second switching-on duration of the first switching tube according to a preset rule so as to reduce the voltage when the second switching tube is switched on again.
Further, the control method may further include: controlling the first switching tube to be closed, and controlling the second switching tube to be closed after the corrected first conduction duration is controlled to be conducted; controlling the power frequency bridge arm to release the energy of the first capacitor within a second dead time, and controlling the first switching tube to be conducted and the second switching tube to be closed until the second dead time is reached; acquiring third voltage parameter information of two ends of the first capacitor again; judging whether the first switching tube is conducted at zero voltage or not according to third voltage parameter information; and when the first switch tube is not switched on at zero voltage, increasing the first switching-on duration of the second switch tube according to a preset rule so as to reduce the voltage when the first switch tube is switched on again.
It should be noted that the first on-time and the second on-time are obtained by calculation, and the first dead time and the second dead time are preset. After waiting for the corresponding dead time, the voltage of the capacitor connected in parallel with the switching tube to be conducted is reduced, even reduced to zero voltage, so that the switching loss of the switching tube can be reduced, and the efficiency of the PFC converter is improved.
In one embodiment of the present invention, the control method may further include: acquiring a reference voltage; carrying out amplitude limiting processing on the reference voltage to obtain a first amplitude limiting voltage; acquiring bus voltage at two ends of a bus capacitor; and calculating a voltage difference value between the first amplitude limiting voltage and the bus voltage, and generating a first conduction time length and a second conduction time length according to the voltage difference value.
As an example, generating the first on-time period and the second on-time period according to the voltage difference may include: carrying out proportional integral adjustment on the voltage difference value to obtain an adjusted voltage; carrying out amplitude limiting processing on the regulated voltage to obtain a second amplitude limiting voltage; and generating a first conduction time length and a second conduction time length according to the second amplitude limiting voltage.
Specifically, as shown in fig. 10, during the voltage soft start, the voltage Vin of the ac source M is obtained, and the reference voltage V is output through the voltage looprefReference voltage VrefAfter amplitude limiting is carried out by a zeroth amplitude limiter, a first amplitude limiting voltage is obtained
Figure BDA0002619590390000041
Then obtaining the voltage Vfpc at two ends of the bus capacitor Ci, and calculating
Figure BDA0002619590390000042
And Vfpc, and inputs the difference to the second of the voltage loopsA PI controller. Further, the characteristics can be balanced according to the volt-second of the inductance. The first conduction time period T of the second high-frequency switch tube P2 is calculated by the following formula (1)onAnd a second conduction time period T of the first high-frequency switch tube P1off：
Figure BDA0002619590390000051
Wherein, IBIs the zero-crossing current of the second switching tube, i.e. ig, L shown in FIG. 4SThe inductance value of the inductor L1 is,
Vinis the peak value of AC source voltage, w is the angular frequency of AC source voltage, IoIs the maximum value of the current flowing through the inductor L1.
It should be noted that the zero voltage conduction control may be executed in a cycle, and when the switching tube is turned on at zero voltage, the first conduction time period and the second conduction time period may be calculated by using the formula (1) again, and the subsequent control may be performed.
For the understanding of the zero voltage conduction control of the switching tube, the following description is made with reference to fig. 1, 4-9:
in the embodiment of the invention, a CRM (Critical Conduction Mode) control Mode can be adopted to control the PFC circuit, so that the PFC circuit can realize low-voltage even zero-voltage Conduction of a high-frequency switching tube in a full-voltage range, thereby reducing switching loss of the switching tube and improving efficiency of the PFC converter.
Specifically, the control of the first high-frequency switch tube P1 (the second switch tube) and the second high-frequency switch tube P2 (the first switch tube) in fig. 1 and 2 is taken as an example. Referring to fig. 4, VgsP2 and VgsP1 are driving pulses of the high-frequency switching tubes P2 and P1, respectively, VdsP2 is the Vds voltage (i.e., the voltage between the drain and the source) of the high-frequency switching tube P2, and iL is the current flowing through the inductor L1. In CRM mode, the PFC circuit operation includes 5 stages, i.e. ton stage, ts1 stage, toff stage, tg stage and ts2 stage in fig. 4, corresponding to five states respectively, for each switching cycle. And, in each switching period, the zero crossing forms a negative current ig to perform LC resonance, and the zero voltage conduction of the high-frequency switching tube can be controlled based on the negative current ig.
Referring to fig. 4 and 5, in the Ton phase, the first high-frequency switch tube P1 is turned off, the second high-frequency switch tube P2 is turned on for the first on-time Ton, and the PFC circuit operates in the forward energy storage process. During this time period, the current output by the AC source AC returns to the AC source AC through the inductor L1, the second high-frequency switching tube P2 and the power-frequency switching tube P6, the inductor L1 charges, the voltage VP1 between the drain and the source of the first high-frequency switching tube P1 (i.e., the voltage across the capacitor C1) is Vpfc, and the voltage between the drain and the source of the second high-frequency switching tube P2 (i.e., the voltage across the capacitor C2) is VdsP2 shown in fig. 4 is 0V, where Vpfc is the voltage across the bus capacitor Ci.
Referring to fig. 4 and 6, in the ts1 phase, the first high-frequency switch tube P1 and the second high-frequency switch tube P2 are both turned off and continue for the first dead time, that is, ts1, and the switch tubes of the PFC circuit operate in the commutation process. At this stage, the capacitor C1 connected in parallel with the first high-frequency switch tube P1 discharges, and the voltage between the drain and the source of the first high-frequency switch tube P1 changes from Vpfc to 0V; the capacitor C2 connected in parallel with the second high-frequency switch tube P2 is charged, and the voltage VdsP2 between the drain and source of the second high-frequency switch tube P2 is changed from 0V to Vpfc.
Referring to fig. 4 and 7, in the toff stage, the first high-frequency switching tube P1 is turned on, the turn-on time is toff, the second high-frequency switching tube P2 is turned off, the inductor L1 discharges, the voltage between the drain and the source of the first high-frequency switching tube P1 is 0V, and the voltage VdsP2 between the drain and the source of the second high-frequency switching tube P2 keeps Vpfc constant.
Referring to fig. 4 and 8, in the tg stage, the first high-frequency switch P1 is turned on for the on-time tg, the second high-frequency switch P2 is turned off, and the PFC circuit operates in the forward process, where tg + toff is the second on-time Toff. The voltage between the drain electrode and the source electrode of the first high-frequency switching tube P1 is kept at 0V, and the voltage Vdsp2 between the drain electrode and the source electrode of the second high-frequency switching tube P2 is kept at Vpfc.
Referring to fig. 4 and 9, in the ts2 phase, the first high-frequency switch P1 and the second high-frequency switch P2 are both turned off and continue for the second dead time ts2, and the PFC circuit operates in an oscillation process. At this stage, the capacitor C1 connected in parallel with the first high-frequency switch tube P1 is charged, the capacitor C2 connected in parallel with the second high-frequency switch tube P2 is discharged, the voltage between the drain and the source of the first high-frequency switch tube P1 is changed from 0V to Vpfc, and the voltage VdsP2 between the drain and the source of the second high-frequency switch tube P2 is reduced from Vpfc to 0V. Based on this, when the VgsP2 starts to be driven, the voltage of the VdsP2 of the high-frequency switch tube P2 is already reduced to zero, so that zero voltage conduction can be realized.
As an example, the first voltage parameter information or the second voltage parameter information or the third voltage parameter information is a voltage change amplitude; judging whether the first switch tube or the second switch tube is conducted at zero voltage according to the voltage parameter information, comprising: judging whether the voltage change amplitude exceeds a preset amplitude threshold value or not; if the voltage does not exceed the preset voltage threshold, judging that the first switching tube or the second switching tube is conducted at zero voltage; if the voltage exceeds the preset value, the first switch tube or the second switch tube is judged to be not conducted with zero voltage.
The amplitude threshold value can be calibrated according to actual charging and discharging requirements.
Specifically, as shown in fig. 4, at the time when the second high-frequency switch tube P2 is turned on, if the obtained voltage variation amplitude of the second high-frequency switch tube P2 exceeds the preset amplitude threshold, it indicates that the drain-source voltage VdsP2 of the second high-frequency switch tube P2 suddenly changes, and the second high-frequency switch tube P2 does not achieve zero-voltage conduction. If the obtained voltage change amplitude of the second high-frequency switch tube P2 does not exceed the preset amplitude threshold, it indicates that the drain-source voltage of the second high-frequency switch tube P2 does not suddenly change, and the second high-frequency switch tube P2 realizes zero-voltage conduction.
As an example, the preset rule is: and the corresponding conduction duration of the first switch tube or the second switch tube in the previous period plus the preset increment. For example, increasing the first on duration may include: and correcting the first conduction time length into a sum of the first conduction time length and a preset increment.
Specifically, since the conduction time of the first high-frequency switch tube P1 and the conduction time of the second high-frequency switch tube P2 can both be calculated by software, the drain-source voltage of the second high-frequency switch tube P2 can be detected at the moment when the second high-frequency switch tube P2 is turned on, and when the second high-frequency switch tube P2 does not realize zero-voltage conduction, the first conduction time duration Toff can be corrected in a software control manner, for example, Toff linearly increases by a fixed step length Tm, and Tm is a fixed value greater than 0. Therefore, the sufficient negative current can make the drain-source voltage drop of the second high-frequency switch tube P2 zero before the second high-frequency switch tube P2 is conducted, so that the zero-voltage conduction of the second high-frequency switch tube P2 can be realized.
In other words, referring to fig. 10, while Ton and Toff are calculated, the ZVS circuit (zero-crossing detection circuit) in fig. 10 detects the drain-source voltage VP2 of the second high-frequency switching tube P2, when the second high-frequency switching tube P2 is turned on again after the second dead time, the ZVS controller may determine whether the second high-frequency switching tube P2 is turned on at zero voltage or not according to the ZCD signal (including the voltage information of VP 2) sent by the ZVS circuit, and if the second high-frequency switching tube P2 is not turned on at zero voltage, the ZVS controller performs step correction on the second time Toff until the second high-frequency switching tube P2 is turned on at zero voltage, and stops the correction.
It should be noted that, when the second high-frequency switching tube P2 does not achieve zero-voltage conduction, the ZVS controller enters a correction interrupt, corrects Toff to Toff _ correct, and inputs the calculated Ton and Toff and the corrected Toff _ correct to the SPWM module during the interrupt time to generate the driving signal of the switching tube of the PFC.
According to the control method of the PFC circuit in the vehicle-mounted charging system, disclosed by the embodiment of the invention, soft switching of each high-frequency switching tube of the PFC can be realized through software control, so that low-voltage even zero-voltage conduction of the high-frequency switching tube in the PFC circuit is realized, the turn-on loss and the break loss of the high-frequency switching tube are reduced, and the working efficiency of the vehicle-mounted charging system is favorably improved.
Further, the present invention provides a vehicle-mounted charging system, as shown in fig. 11, a vehicle-mounted charging system 10 includes a PFC circuit 11 and a control module 12, where the PFC circuit 11 includes at least one phase high-frequency arm, the high-frequency arm includes a first switch tube, a second switch tube and a first capacitor, the first capacitor is connected in parallel with the first switch tube, and the control module 12 is configured to: when the first switch tube is controlled to be conducted and the second switch tube is controlled to be closed, first voltage parameter information of two ends of the first capacitor is obtained; judging whether the first switching tube is conducted at zero voltage or not according to the first voltage parameter information; when the first switch tube is not switched on at zero voltage, the first switching-on duration of the second switch tube is increased according to a preset rule so as to reduce the voltage when the first switch tube is switched on again.
In an embodiment of the present invention, the PFC circuit 11 further includes a phase power frequency bridge arm, where the power frequency bridge arm is connected in parallel with the high frequency bridge arm; the high-frequency bridge arm also comprises a second capacitor, and the second capacitor is connected with the second switching tube in parallel; the control module 12 is further configured to: after the first switching tube is controlled to be conducted and the second switching tube is controlled to be closed for a second conduction time, the first switching tube is controlled to be closed and the second switching tube is controlled to be closed; controlling the power frequency bridge arm to release the energy of the second capacitor within the first dead time, and controlling the first switching tube to be closed and the second switching tube to be conducted until the first dead time is reached; acquiring second voltage parameter information at two ends of a second capacitor; judging whether the second switching tube is conducted at zero voltage or not according to the second voltage parameter information; and when the second switching tube is not switched on at zero voltage, increasing the second switching-on duration of the first switching tube according to a preset rule so as to reduce the voltage when the second switching tube is switched on again.
According to the vehicle-mounted charging system provided by the embodiment of the invention, the soft switching of each high-frequency switching tube of the PFC can be realized through the control method of the PFC circuit, so that the zero-voltage conduction of the high-frequency switching tube in the PFC circuit is realized, the turn-on loss and the break loss of the high-frequency switching tube are reduced, and the working efficiency of the vehicle-mounted charging system is favorably improved.
Further, the present invention proposes a vehicle, as shown in fig. 12, a vehicle 20 includes the above-described on-vehicle charging system 10.
When the vehicle-mounted charging system provided by the embodiment of the invention is applied to the control method of the PFC circuit in the vehicle-mounted charging system, the soft switching of each high-frequency switching tube of the PFC can be realized, so that the zero-voltage conduction of the high-frequency switching tube in the PFC circuit is realized, the turn-on loss and the break loss of the high-frequency switching tube are reduced, and the working efficiency of the vehicle-mounted charging system is favorably improved.
It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (10)

1. A control method of a PFC circuit in a vehicle-mounted charging system is characterized in that the PFC circuit comprises at least one phase high-frequency bridge arm, the high-frequency bridge arm comprises a first switch tube, a second switch tube and a first capacitor, the first capacitor is connected with the first switch tube in parallel, and the control method comprises the following steps:
when the first switch tube is controlled to be switched on and the second switch tube is controlled to be switched off, first voltage parameter information of two ends of the first capacitor is obtained;
judging whether the first switching tube is conducted at zero voltage or not according to the first voltage parameter information;
and when the first switch tube is not switched on at zero voltage, increasing the first switching-on duration of the second switch tube according to a preset rule so as to reduce the voltage when the first switch tube is switched on again.
2. The control method according to claim 1, wherein the PFC circuit further comprises a phase power frequency leg, the power frequency leg being connected in parallel with the high frequency leg; the high-frequency bridge arm also comprises a second capacitor, and the second capacitor is connected with the second switching tube in parallel; the control method further comprises the following steps:
after the first switching tube is controlled to be switched on and the second switching tube is controlled to be switched off for a second switching duration, the first switching tube is controlled to be switched off and the second switching tube is controlled to be switched off;
controlling the power frequency bridge arm to release the energy of the second capacitor within a first dead time, and controlling the first switching tube to be closed and the second switching tube to be conducted until the first dead time is reached;
acquiring second voltage parameter information at two ends of the second capacitor;
judging whether the second switching tube is conducted at zero voltage or not according to the second voltage parameter information;
and when the second switching tube is not switched on at zero voltage, increasing the second switching-on duration of the first switching tube according to a preset rule so as to reduce the voltage when the second switching tube is switched on again.
3. The control method according to claim 2, characterized by comprising:
controlling the first switch tube to be closed, and controlling the second switch tube to be closed after the corrected first conduction duration is controlled to be conducted;
controlling the power frequency bridge arm to release the energy of the first capacitor within a second dead time, and controlling the first switching tube to be conducted and the second switching tube to be closed until the second dead time is reached;
acquiring third voltage parameter information of two ends of the first capacitor again;
judging whether the first switching tube is conducted at zero voltage or not according to the third voltage parameter information;
and when the first switch tube is not switched on at zero voltage, increasing the first switching-on duration of the second switch tube according to a preset rule so as to reduce the voltage when the first switch tube is switched on again.
4. The control method according to claim 3, wherein the first voltage parameter information or the second voltage parameter information or the third voltage parameter information is a voltage change amplitude; judging whether the first switch tube or the second switch tube is conducted at zero voltage according to the voltage parameter information, comprising:
judging whether the voltage change amplitude exceeds a preset amplitude threshold value or not;
if the voltage does not exceed the preset voltage threshold, judging that the first switching tube or the second switching tube is conducted at zero voltage;
if the voltage exceeds the preset value, the first switch tube or the second switch tube is judged to be not conducted under zero voltage.
5. A control method according to one of claims 1 to 3, characterized in that the preset rules are: and in the previous period, the corresponding conduction duration of the first switch tube or the second switch tube is plus a preset increment.
6. The control method according to claim 1, wherein the PFC circuit further comprises a bus capacitor connected in parallel with the high frequency leg; the control method further comprises the following steps:
acquiring a reference voltage;
carrying out amplitude limiting processing on the reference voltage to obtain a first amplitude limiting voltage;
acquiring bus voltage at two ends of the bus capacitor;
and calculating a voltage difference value between the first amplitude limiting voltage and the bus voltage, and generating the first conduction time length and the second conduction time length according to the voltage difference value.
7. The control method of claim 6, wherein said generating the first on-time period and the second on-time period according to the voltage difference comprises:
carrying out proportional integral adjustment on the voltage difference value to obtain an adjusted voltage;
carrying out amplitude limiting processing on the adjusting voltage to obtain a second amplitude limiting voltage;
and generating the first conduction time length and the second conduction time length according to the second amplitude limiting voltage.
8. An in-vehicle charging system, characterized by comprising:
the PFC circuit comprises at least one phase high-frequency bridge arm, the high-frequency bridge arm comprises a first switching tube, a second switching tube and a first capacitor, and the first capacitor is connected with the first switching tube in parallel;
a control module configured to: when the first switch tube is controlled to be switched on and the second switch tube is controlled to be switched off, first voltage parameter information of two ends of the first capacitor is obtained; judging whether the first switching tube is conducted at zero voltage or not according to the first voltage parameter information; and when the first switch tube is not switched on at zero voltage, increasing the first switching-on duration of the second switch tube according to a preset rule so as to reduce the voltage when the first switch tube is switched on again.
9. The vehicle-mounted charging system according to claim 8, wherein the PFC circuit further comprises a phase power frequency leg, the power frequency leg being connected in parallel with the high frequency leg; the high-frequency bridge arm also comprises a second capacitor, and the second capacitor is connected with the second switching tube in parallel;
the control module is further configured to: after the first switching tube is controlled to be switched on and the second switching tube is controlled to be switched off for a second switching duration, the first switching tube is controlled to be switched off and the second switching tube is controlled to be switched off;
controlling the power frequency bridge arm to release the energy of the second capacitor within a first dead time, and controlling the first switching tube to be closed and the second switching tube to be conducted until the first dead time is reached; acquiring second voltage parameter information at two ends of the second capacitor; judging whether the second switching tube is conducted at zero voltage or not according to the second voltage parameter information; and when the second switching tube is not switched on at zero voltage, increasing the second switching-on duration of the first switching tube according to a preset rule so as to reduce the voltage when the second switching tube is switched on again.
10. A vehicle characterized by comprising an on-board charging system according to any one of claims 8 to 9.
CN202010779205.XA 2020-08-05 2020-08-05 Vehicle, vehicle-mounted charging system and control method of PFC circuit in vehicle-mounted charging system Pending CN114070032A (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106560987A (en) * 2015-10-06 2017-04-12 英飞凌科技奥地利有限公司 Circuitry For Power Factor Correction And Methods Of Operation
CN110138202A (en) * 2013-12-19 2019-08-16 德克萨斯仪器股份有限公司 Device and method for zero voltage switching

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110138202A (en) * 2013-12-19 2019-08-16 德克萨斯仪器股份有限公司 Device and method for zero voltage switching
CN106560987A (en) * 2015-10-06 2017-04-12 英飞凌科技奥地利有限公司 Circuitry For Power Factor Correction And Methods Of Operation

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