CN116565981A

CN116565981A - Electric vehicle, charge-discharge circuit thereof, and control method of charge-discharge circuit

Info

Publication number: CN116565981A
Application number: CN202210100953.XA
Authority: CN
Inventors: 陈明文; 刘文昉; 郑乐平; 薛鹏辉; 王亮
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2023-08-08

Abstract

The invention discloses an electric vehicle, a charging and discharging circuit thereof and a control method of the charging and discharging circuit. The charge-discharge circuit includes: when the electric vehicle works in an alternating-current charging and discharging mode, at least part of switching tubes in the bidirectional DC/DC conversion unit, the motor control unit, the generator control unit and the OBC control unit form a part of a charging and discharging loop, so that energy isolation transmission between the power battery unit and external alternating-current charging and discharging equipment is realized. In the invention, the leakage current of the charge-discharge circuit can be reduced, the safety and reliability of the charge-discharge circuit can be improved, and the weight and volume of the charge-discharge circuit can be reduced by forming a part of the charge-discharge circuit through at least part of the switch tube.

Description

Electric vehicle, charge-discharge circuit thereof, and control method of charge-discharge circuit

Technical Field

The invention relates to the technical field of electric vehicles, in particular to an electric vehicle, a charging and discharging circuit thereof and a control method of the charging and discharging circuit.

Background

With the development of electric vehicle technology, more and more users are beginning to use electric vehicles. In the related art, an electric vehicle includes an on-board OBC ac or dc charging circuit to meet the need for ac or dc charging of the electric vehicle. However, in-vehicle OBCs are typically put into service when the vehicle is in a stationary state of charge, and the in-vehicle OBC assembly becomes a fixed load for the electric vehicle when the vehicle is in a traveling state. Therefore, in order to increase the driving range of an electric vehicle, reducing or minimizing the weight and volume of the on-board OBC becomes a necessary solution.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a charge-discharge circuit for an electric vehicle, which can realize the boosting functions of different voltage systems, expand the working voltage range of a power supply circuit, improve the bidding capability of the product, and increase the applicability of the product.

A second object of the present invention is to propose an electric vehicle.

A third object of the present invention is to provide a method for controlling a charge/discharge circuit of an electric vehicle.

To achieve the above object, an embodiment of a first aspect of the present invention provides a charge and discharge circuit of an electric vehicle, including: the electric vehicle is characterized by comprising a bidirectional DC/DC conversion unit, a motor control unit, a generator control unit, an isolation conversion unit, an OBC control unit, a first controllable switch unit and a second controllable switch unit, wherein the bidirectional DC/DC conversion unit is connected to a power battery unit, a direct current end of the OBC control unit is connected to the power battery unit through the first controllable switch unit, a first alternating current end of the OBC control unit is connected to an external alternating current charging and discharging device, a second alternating current end of the OBC control unit is connected with the isolation conversion unit, the isolation conversion unit is further connected with the motor control unit and the generator control unit through the second controllable switch unit respectively, and when the electric vehicle works in an alternating current charging and discharging mode, at least part of switch tubes in the bidirectional DC/DC conversion unit, the motor control unit, the generator control unit and the OBC control unit form a part of a charging and discharging loop, so that the battery unit and the external charging and discharging device can be isolated.

According to the charge-discharge circuit of the electric vehicle, disclosed by the embodiment of the invention, not only can the leakage current of the charge-discharge circuit be reduced and the safety and reliability of the charge-discharge circuit be improved, but also the multiplexing of the switch tubes is realized by forming a part of the charge-discharge circuit through at least part of the switch tubes, so that the number of the switch tubes in the charge-discharge circuit can be reduced and the weight and the volume of the charge-discharge circuit are reduced.

In some embodiments of the present invention, when the electric vehicle works in an ac charging mode, the first controllable switch unit is opened, the second controllable switch unit is closed, the OBC control unit rectifies and PFC the ac power provided by the external ac charging and discharging device, then inverts and outputs a first ac power, the isolation conversion unit performs isolation conversion on the first ac power, outputs a second ac power, and any one phase of bridge arm in the motor control unit and any one phase of bridge arm in the generator control unit form a rectifying H-bridge, rectifies the second ac power, and outputs a first dc power to charge the power battery unit.

In some embodiments of the present invention, the isolation conversion unit further performs AC-DC isolation conversion on the first alternating current, and outputs a second direct current to charge a low voltage battery unit or power a low voltage device in the electric vehicle.

In some embodiments of the present invention, the bidirectional DC/DC conversion unit is further configured to perform step-down control on the first direct current, so as to output the stepped-down first direct current to the power battery unit for charging.

In some embodiments of the present invention, when the electric vehicle works in an ac discharging mode, the first controllable switch unit is opened, the second controllable switch unit is closed, any one phase of bridge arm in the motor control unit and any one phase of bridge arm in the generator control unit form an inverted H-bridge, a dc power source provided by the power battery unit is inverted into a third ac power, the isolation conversion unit performs isolation conversion on the third ac power, outputs a fourth ac power, and the OBC control unit rectifies and inverts the fourth ac power and provides the fourth ac power to the external ac charging and discharging device.

In some embodiments of the present invention, the isolation conversion unit further performs AC-DC isolation conversion on the third alternating current, and outputs a second direct current to charge a low voltage battery unit or power a low voltage device in the electric vehicle.

In some embodiments of the present invention, the bidirectional DC/DC conversion unit is further configured to boost-control the DC power supplied from the power battery unit, so as to output the boosted DC power to the inverter H-bridge for inversion.

In some embodiments of the present invention, when the electric vehicle is operated in a driving mode, the first controllable switch unit is closed, the second controllable switch unit is opened, the motor control unit drives and controls a driving motor in the electric vehicle according to a direct current power supply provided by the power battery unit, the generator control unit operates in a DC-AC inversion state or an AC-DC controllable rectification state, the OBC control unit inverts a direct current power supply provided by the power battery unit into an alternating current power supply, the isolation conversion unit performs AC-DC isolation conversion on the alternating current power supply, and outputs a second direct current power to charge a low voltage device in the electric vehicle.

In some embodiments of the present invention, the bidirectional DC/DC conversion unit is further configured to boost-control the direct current power supplied from the power battery unit, so that the motor control unit performs drive control of the driving motor in the electric vehicle according to the boosted direct current power.

In some embodiments of the present invention, the first controllable switch unit includes a first switch and a second switch, the second controllable switch unit includes a third switch and a fourth switch, wherein one end of the first switch is connected to a positive terminal of the power battery unit, the other end of the first switch is connected to a direct current positive terminal of the OBC control unit, one end of the second switch is connected to a negative terminal of the power battery unit, the other end of the second switch is connected to a direct current negative terminal of the OBC control unit, one end of the third switch is connected to a midpoint of any one phase of the bridge arm in the motor control unit, the other end of the third switch is connected to a first alternating current terminal of any one phase of the generator control unit, and one end of the fourth switch is connected to a second alternating current terminal of the isolation conversion unit.

In some embodiments of the present invention, the OBC control unit includes a three-phase bridge and an H-bridge, wherein an ac end of the three-phase bridge is connected to an external ac charging and discharging device as a first ac end of the OBC control unit, a dc end of an upper bridge arm of the three-phase bridge is used as a dc positive end of the OBC control unit, a dc end of a lower bridge arm of the three-phase bridge is used as a dc negative end of the OBC control unit, an ac end of the H-bridge is connected to the isolation conversion unit as a second ac end of the OBC control unit, a dc end of an upper bridge arm of the H-bridge is connected to a dc end of an upper bridge arm of the three-phase bridge, and a dc end of a lower bridge arm of the H-bridge is connected to a dc end of a lower bridge of the three-phase bridge.

In some embodiments of the present invention, the isolation conversion unit includes an isolation transformer, a fifth inductance, a sixth inductance, a fourth capacitance, a fifth capacitance, a first diode, and a second diode, where the isolation transformer includes a first winding, a second winding, and a third winding, where the same-name end of the first winding is connected to a second ac end of the OBC control unit through the fifth inductance, the different-name end of the first winding is connected to another second ac end of the OBC control unit through the fourth capacitance, the same-name end of the second winding is connected to the third switch through the sixth inductance, the different-name end of the second winding is connected to the fourth switch through the fifth capacitance, the same-name end of the third winding is connected to an anode of the first diode, a cathode of the first diode is used as a low voltage output positive electrode of the isolation conversion unit, the different-name end of the third winding is connected to a cathode of the second diode, the same-name end of the third winding is used as a low voltage output positive electrode of the isolation conversion unit, and the cathode of the second diode is used as a low voltage output of the low voltage power supply unit or a cathode of the low voltage power supply unit.

In some embodiments of the present invention, when the first controllable switch unit and the second controllable switch unit are both closed, the OBC control unit inverts the DC power provided by the power battery unit and provides the DC power to the external AC charging and discharging device, any one phase of bridge arm in the motor control unit and any one phase of bridge arm in the generator control unit form an inverted H bridge, the DC power provided by the power battery unit is inverted into a third AC power, and the isolation conversion unit performs AC-DC isolation conversion on the third AC power and outputs a second DC power to charge a battery unit or power a low-voltage device in the electric vehicle.

In some embodiments of the present invention, when the first controllable switch unit is closed and the second controllable switch unit is opened, the OBC control unit performs inversion control on the DC power provided by the power battery unit, and outputs a first AC power and a second AC power, where the first AC power is used for being provided to the external AC charging and discharging device, and the isolation conversion unit performs AC-DC isolation conversion on the second AC power, and outputs a second DC power to charge or power a low-voltage device of the battery unit in the electric vehicle.

To achieve the above object, a second aspect of the present invention provides an electric vehicle including the charge-discharge circuit of the electric vehicle according to any one of the above embodiments.

According to the electric vehicle provided by the embodiment of the invention, the leakage current of the charge-discharge circuit can be reduced, the safety and the reliability of the charge-discharge circuit are improved, and the multiplexing of the switch tubes is realized by forming a part of the charge-discharge circuit through at least part of the switch tubes, so that the number of the switch tubes in the charge-discharge circuit can be reduced, and the weight and the volume of the charge-discharge circuit are reduced.

To achieve the above object, a third aspect of the present invention provides a control method of a charge-discharge circuit of an electric vehicle according to any one of the above embodiments, the control method including: determining an operating mode of the electric vehicle; when the working mode of the electric vehicle is an alternating current charging and discharging mode, the switching states of the first controllable switching unit and the second controllable switching unit are configured, so that at least part of switching tubes in the bidirectional DC/DC conversion unit, the motor control unit, the generator control unit and the OBC control unit form a part of a charging and discharging loop, and energy isolation transmission between the power battery unit and the external alternating current charging and discharging equipment is realized.

According to the control method of the charge-discharge circuit of the electric vehicle, disclosed by the embodiment of the invention, not only can the leakage current of the charge-discharge circuit be reduced and the safety and reliability of the charge-discharge circuit be improved, but also the multiplexing of the switch tubes is realized by forming a part of the charge-discharge circuit through at least part of the switch tubes, so that the number of the switch tubes in the charge-discharge circuit can be reduced and the weight and the volume of the charge-discharge circuit are reduced.

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

Fig. 1 is a schematic diagram of a charge-discharge circuit of an electric vehicle according to one embodiment of the invention;

fig. 2 is a schematic diagram of a charge-discharge circuit of an electric vehicle according to one embodiment of the invention;

fig. 3 is a schematic diagram of a charge-discharge circuit of an electric vehicle according to one embodiment of the invention;

fig. 4 is a schematic diagram of a charge-discharge circuit of an electric vehicle according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a charge-discharge circuit of an electric vehicle according to an embodiment of the invention;

fig. 6 is a schematic diagram of a charge-discharge circuit of an electric vehicle according to one embodiment of the invention;

Fig. 7 is a schematic diagram of a charge-discharge circuit of an electric vehicle according to an embodiment of the invention;

fig. 8 is a flowchart of a control method of a charge and discharge circuit of an electric vehicle according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

An electric vehicle and a charge and discharge circuit and a control method of the charge and discharge circuit thereof according to an embodiment of the present invention are described below with reference to the accompanying drawings.

In some embodiments of the present invention, as shown in fig. 1, the present invention proposes a charge and discharge circuit of an electric vehicle, the charge and discharge circuit comprising: the bidirectional DC/DC conversion unit 10, the motor control unit 20 and the generator control unit 30, and the isolation conversion unit 40, the OBC control unit 50, the first controllable switch unit 60 and the second controllable switch unit 70 are connected to each other, the bidirectional DC/DC conversion unit 10 is connected to the power battery unit 80, the direct current end 52 of the OBC control unit 50 is connected to the power battery unit 80 through the first controllable switch unit 60, the first alternating current end 54 of the OBC control unit 50 is connected to an external alternating current charging and discharging device, the second alternating current end 56 of the OBC control unit 50 is connected to the isolation conversion unit 40, and the isolation conversion unit 40 is also connected to the motor control unit 20 and the generator control unit 30 through the second controllable switch unit 70, respectively, wherein when the electric vehicle is operated in an alternating current charging and discharging mode, at least part of the switching tubes in the bidirectional DC/DC conversion unit 10, the motor control unit 20, the generator control unit 30 and the OBC control unit 50 form a part of a charging and discharging circuit by configuring the switching states of the first controllable switch unit 60 and the second controllable switch unit 70, thereby realizing the energy transfer between the power battery unit 80 and the external alternating current charging and discharging device.

According to the charge-discharge circuit of the electric vehicle, disclosed by the embodiment of the invention, not only can the leakage current of the charge-discharge circuit be reduced and the safety and reliability of the charge-discharge circuit be improved, but also the multiplexing of the switch tubes is realized by forming a part of the charge-discharge circuit through at least part of the switch tubes, so that the number of the switch tubes in the charge-discharge circuit can be reduced and the weight and the volume of the charge-discharge circuit are reduced. Meanwhile, the fixed load of the electric vehicle is reduced, the driving mileage of the electric vehicle is improved, and the problem of the anxiety of the driving mileage of the electric vehicle in the using process is relieved.

It can be understood that, in the related art, for the scheme of performing energy isolation transfer, the charge-discharge circuit of the electric vehicle includes a bidirectional DC/DC conversion unit, a motor control unit, and a generator control unit, which are connected to each other, and an H-bridge composed of the isolation conversion unit, an OBC control unit, and an additional 4 switching tubes, the bidirectional DC/DC conversion unit is connected to the power battery unit, a first ac end of the OBC control unit is connected to the external ac charge-discharge device, a second ac end of the OBC control unit is connected to the isolation conversion unit, the isolation conversion unit is further connected to the power battery unit through the H-bridge composed of the additional 4 switching tubes, and when the electric vehicle operates in the ac charge-discharge mode, the energy isolation transfer between the power battery unit and the external ac charge-discharge device is implemented through the H-bridge composed of the isolation conversion unit and the additional 4 switching tubes; when the electric vehicle works in a running mode, energy transmission between the power battery unit and the motor control unit and between the power battery unit and the generator control unit is realized through the bidirectional DC/DC conversion unit. That is, the charge-discharge circuit of the electric vehicle in the related art requires more switching tubes to realize energy isolation transmission, which increases the weight and volume of the charge-discharge circuit, increases the fixed load of the electric vehicle, and reduces the driving range of the electric vehicle after a single full charge.

In the technical scheme of the invention, 4 additional switching tubes in the related art are saved, and in the process that the vehicle works in an alternating current charging and discharging mode, the switching tubes in the motor control unit 20 and the generator control unit 30 are multiplexed to form an H bridge, and the energy isolation transmission between the power battery unit 80 and external alternating current charging and discharging equipment is realized by configuring the switching states of the first controllable switching unit 60 and the second controllable switching unit 70 and the OBC control unit 50, the isolation conversion unit 40, the motor control unit 20, the generator control unit 30 and the bidirectional DC/DC conversion unit 10.

Specifically, the bidirectional DC/DC conversion unit 10, the motor control unit 20, and the generator control unit 30 may be connected by bus bars. In some embodiments, the charge-discharge circuit may include a first capacitor C3, where the first capacitor C3 is disposed between the bidirectional DC/DC conversion unit 10 and the motor control unit 20, and the first capacitor C3 is connected to the bus, and the first capacitor C3 can perform an energy storage function. In some embodiments, the second capacitor C4 is connected in parallel to two ends of the power battery unit 80, and the second capacitor C4 may be used to improve electromagnetic compatibility (Electromagnetic Compatibility, EMC) performance of the electric vehicle.

The bidirectional DC/DC converting unit 10 may include a first switching tube Q1, a second switching tube Q2, a third switching tube Q3, a fourth switching tube Q4, a first inductor L3, and a second inductor L4. The source electrode of the first switching tube Q1 is connected to the drain electrode of the second switching tube Q2, the source electrode of the third switching tube Q3 is connected to the drain electrode of the fourth switching tube Q4, the drain electrode of the first switching tube Q1 is connected to the drain electrode of the third switching tube Q3, and the source electrodes of the second switching tube Q2 and the fourth switching tube Q4 are connected to the negative electrode terminal of the power battery unit 80 through a bus. The first switching tube Q1 and the second switching tube Q2 form a first bridge arm of the bidirectional DC/DC conversion unit 10, and a midpoint of the first bridge arm of the bidirectional DC/DC conversion unit 10 is connected to a positive terminal of the power battery unit 80 through a first inductor L3. The third switching tube Q3 and the fourth switching tube Q4 form a second bridge arm of the bidirectional DC/DC conversion unit 10, and a midpoint of the second bridge arm of the bidirectional DC/DC conversion unit 10 is connected to the positive terminal of the power battery unit 80 through a second inductor L4.

The first arm of the motor control unit 20 includes a fifth switching tube M1 and a sixth switching tube M4, the second arm of the motor control unit 20 includes a seventh switching tube M3 and an eighth switching tube M6, and the third arm of the motor control unit 20 includes a ninth switching tube M5 and a tenth switching tube M2. The source electrode of the fifth switching tube M1 is connected to the drain electrode of the sixth switching tube M4, the source electrode of the seventh switching tube M3 is connected to the drain electrode of the eighth switching tube M6, the source electrode of the ninth switching tube M5 is connected to the drain electrode of the tenth switching tube M2, the drain electrode of the fifth switching tube M1, the drain electrode of the seventh switching tube M3 and the drain electrode of the ninth switching tube M5 are connected, and the source electrode of the sixth switching tube M4, the source electrode of the eighth switching tube M6 and the source electrode of the tenth switching tube M2 are connected to the negative electrode terminal of the power battery unit 80 through a bus.

The first leg of the generator control unit 30 comprises an eleventh switching tube G1 and a twelfth switching tube G4, the second leg of the generator control unit 30 comprises a thirteenth switching tube G3 and a fourteenth switching tube G6, and the third leg of the generator control unit 30 comprises a fifteenth switching tube G5 and a sixteenth switching tube G2. The source of the eleventh switching tube G1 is connected to the drain of the twelfth switching tube G4, the source of the thirteenth switching tube G3 is connected to the drain of the fourteenth switching tube G6, the source of the fifteenth switching tube G5 is connected to the drain of the sixteenth switching tube G2, the drain of the eleventh switching tube G1, the drain of the thirteenth switching tube G3 and the drain of the fifteenth switching tube G5 are connected, and the source of the twelfth switching tube G4, the source of the fourteenth switching tube G6 and the source of the sixteenth switching tube G2 are connected to the negative terminal of the power battery unit 80 through buses. It should be noted that the drain of the first switching tube Q1, the drain of the third switching tube Q3, the drain of the fifth switching tube M1, the drain of the seventh switching tube M3, the drain of the ninth switching tube M5, the drain of the eleventh switching tube G1, the drain of the thirteenth switching tube G3, and the drain of the fifteenth switching tube G5 are connected.

In some embodiments of the present invention, the first controllable switch unit 60 includes a first switch S1 and a second switch S2, the second controllable switch unit 70 includes a third switch S3 and a fourth switch S4, wherein one end of the first switch S1 is connected to the positive terminal of the power battery unit 80, the other end of the first switch S1 is connected to the dc positive terminal 522 of the OBC control unit 50, one end of the second switch S2 is connected to the negative terminal of the power battery unit 80, the other end of the second switch S2 is connected to the dc negative terminal 524 of the OBC control unit 50, one end of the third switch S3 is connected to the midpoint of any one phase leg of the motor control unit 20, the other end of the third switch S3 is connected to the first ac terminal 42 of the isolation conversion unit 40, one end of the fourth switch S4 is connected to the midpoint of any one phase leg of the generator control unit 30, and the other end of the fourth switch S4 is connected to the second ac terminal 44 of the isolation conversion unit 40. In the embodiment shown in fig. 1, one end of the third switch S3 is connected to the midpoint of the third leg of the motor control unit 20, and one end of the fourth switch S4 is connected to the midpoint of the first leg of the generator control unit 30; in other embodiments, one end of the third switch S3 may be connected to a midpoint of the first arm of the motor control unit 20 or a midpoint of the second arm of the motor control unit 20, and one end of the fourth switch S4 may be connected to a midpoint of the second arm of the generator control unit 30 or a midpoint of the third arm of the generator control unit 30, which is not limited herein. It should be noted that when both the first switch S1 and the second switch S2 are turned off, it can be ensured that no matter in positive or negative periods, no ac will be connected into the dc portion, otherwise the isolation will fail.

In some embodiments of the present invention, the OBC control unit 50 includes an H-bridge and a three-phase bridge, wherein an ac end of the three-phase bridge is connected to an external ac charging and discharging device as a first ac end 54 of the OBC control unit 50, a dc end of an upper bridge arm of the three-phase bridge is connected to a dc positive end 522 of the OBC control unit 50, a dc end of a lower bridge arm of the three-phase bridge is connected to the isolated conversion unit 40 as a dc negative end 524 of the OBC control unit 50, an ac end of the H-bridge is connected to an upper bridge arm dc end of the three-phase bridge, and a dc end of the lower bridge arm of the H-bridge is connected to a dc end of the lower bridge arm of the three-phase bridge.

Wherein, the first bridge arm of the H bridge of the OBC control unit 50 includes a seventeenth switching tube B1 and an eighteenth switching tube B2, the second bridge arm of the H bridge of the OBC control unit 50 includes a nineteenth switching tube B3 and a twentieth switching tube B4, the first bridge arm of the three-phase bridge of the OBC control unit 50 includes a twenty first switching tube O1 and a twenty second switching tube O4, the second bridge arm of the three-phase bridge of the OBC control unit 50 includes a twenty third switching tube O3 and a twenty fourth switching tube O6, and the third bridge arm of the three-phase bridge of the OBC control unit 50 includes a twenty fifth switching tube O5 and a twenty sixteen switching tube O2. The source electrode of the seventeenth switching tube B1 is connected with the drain electrode of the eighteenth switching tube B2, the source electrode of the nineteenth switching tube B3 is connected with the drain electrode of the twentieth switching tube B4, the source electrode of the twenty first switching tube O1 is connected with the drain electrode of the twenty second switching tube O4, the source electrode of the twenty third switching tube O3 is connected with the drain electrode of the twenty fourth switching tube O6, and the source electrode of the twenty fifth switching tube O5 is connected with the drain electrode of the twenty sixth switching tube O2. The drain of the seventeenth switching tube B1, the drain of the nineteenth switching tube B3, the drain of the twenty first switching tube O1, the drain of the twenty third switching tube O3, and the drain of the twenty fifth switching tube O5 are connected and serve as the dc positive terminal 522 of the OBC control unit 50. The source of the eighteenth switching tube B2, the source of the twentieth switching tube B4, the source of the twenty-second switching tube O4, the source of the twenty-fourth switching tube O6, and the source of the twenty-sixth switching tube O2 are connected and serve as the dc negative terminal 524 of the OBC control unit 50. The midpoint of the first bridge arm of the three-phase bridge of the OBC control unit 50 is connected to one end of the third inductor L5, the other end of the third inductor L5 is connected to the live wire L of the charge-discharge terminal 90, the midpoint of the second bridge arm of the three-phase bridge of the OBC control unit 50 is connected to one end of the fourth inductor L6, the other end of the fourth inductor L6 is connected to the other end of the third inductor L5, and the midpoint of the third bridge arm of the three-phase bridge of the OBC control unit 50 is connected to the neutral wire N of the charge-discharge terminal 90, wherein the other end of the third inductor L5 and the midpoint of the third bridge arm of the three-phase bridge of the OBC control unit 50 can be understood as the first ac end 54 of the OBC control unit 50. The midpoint of the first leg of the H-bridge of OBC control unit 50 and the midpoint of the second leg of the H-bridge of OBC control unit 50 may be understood as the second ac terminal 56 of OBC control unit 50. The charge-discharge terminal 90 can be used to connect the first ac terminal 54 of the OBC control unit 50 to an external ac charge-discharge device. In some embodiments, the OBC control unit 50 further includes a third capacitor C5, one end of the third capacitor C5 is connected to the dc positive terminal 522 of the OBC control unit 50, the other end of the third capacitor C5 is connected to the dc negative terminal 524 of the OBC control unit 50, and the third capacitor C5 is capable of storing energy.

In some embodiments of the present invention, the isolation transforming unit 40 includes an isolation transformer T1, a fifth inductance L1, a sixth inductance L2, a fourth capacitance C1, a fifth capacitance C2, a first diode D1 and a second diode D2, the isolation transformer T1 includes a first winding n1, a second winding n3, and a third winding n3, wherein a homonymous terminal of the first winding n1 is connected to a second ac terminal of the OBC control unit 50 through the fifth inductance L1, a homonymous terminal of the first winding n1 is connected to another second ac terminal of the OBC control unit 50 through the fourth capacitance C1, a homonymous terminal of the second winding n2 is connected to a third switch S3 through the sixth inductance L2, a homonymous terminal of the second winding n2 is connected to a fourth switch S4 through the fifth capacitance C2, a homonymous terminal of the third winding n3 is connected to an anode of the first diode D1, a negative electrode of the first diode D1 is used as a low voltage output 46 of the isolation transforming unit 40, a negative electrode of the second winding D1 is used as a low voltage output terminal of the low voltage output of the low voltage transforming unit 40, and a negative electrode of the low voltage output of the low voltage transforming unit 48 is connected to the second diode D2 is used as a negative electrode of the low voltage output of the low voltage transforming unit or the low voltage output of the low voltage output cell 46.

External ac charging and discharging devices include, but are not limited to, charging piles, ac grids, other electric vehicles, and electronic devices, among others. Electric vehicles include, but are not limited to, electric-only vehicles, hybrid electric vehicles. The ac charge-discharge mode includes an ac charge mode and an ac discharge mode.

In some embodiments of the present invention, referring to fig. 2, when the electric vehicle operates in the ac charging mode, the first controllable switch unit 60 is opened, the second controllable switch unit 70 is closed, the OBC control unit 50 rectifies and PFC-corrects the ac power provided by the external ac charging and discharging device, then inverts and outputs the first ac power, the isolation conversion unit 40 performs the isolation conversion on the first ac power, outputs the second ac power, any one phase of bridge arm in the motor control unit 20 and any one phase of bridge arm in the generator control unit 30 form a rectified H bridge, rectifies the second ac power, and outputs the first dc power to charge the power battery unit 80.

In this way, by multiplexing part of the switching tubes in the motor control unit 20 and the generator control unit 30, the power battery unit 80 is charged.

Specifically, when the electric vehicle is operating in the ac charging mode, the first switch S1 and the second switch S2 are opened, and the third switch S3 and the fourth switch S4 are closed.

Referring to fig. 2, in a state where the live wire L is positive and the neutral wire N is negative, the twenty-sixth switching tube O2 is controlled to be turned on, and the twenty-fifth switching tube O5 is controlled to be turned off. Further, the twenty-first switching tube O1 and the twenty-second switching tube O4 are controlled to be alternately turned on, the twenty-third switching tube O3 and the twenty-fourth switching tube O6 are controlled to be alternately turned on and off in a certain period when the twenty-third switching tube O3 is delayed than the twenty-first switching tube O1, and the twenty-fourth switching tube O6 is controlled to be turned on and off in a certain period when the twenty-second switching tube O4 is delayed. When the twenty-second switching tube O4 and the twenty-fourth switching tube O6 are turned on and the twenty-first switching tube O1 and the twenty-third switching tube O3 are turned off, the power flow direction can be understood as: the third inductor L5 and the fourth inductor L6 can be charged in the process of the live wire l→the third inductor L5→the twenty-second switching tube O4→the twenty-sixteen switching tube O2→the zero line N, the live wire l→the fourth inductor l6→the twenty-fourth switching tube O6→the twenty-sixteen switching tube O2→the zero line N, so that the third inductor L5 and the fourth inductor L6 can store electric energy. When the twenty-second switching tube O4 and the twenty-fourth switching tube O6 are turned off and the twenty-first switching tube O1 and the twenty-third switching tube O3 are turned on, the power flow direction can be understood as: the third capacitor C5 can be charged in the process of the live wire L, the third inductor L5, the twenty-first switching tube O1, the third capacitor C5, the twenty-sixth switching tube O2, the zero line N, the live wire L, the fourth inductor L6, the twenty-third switching tube O3, the third capacitor C5, the twenty-sixth switching tube O2 and the zero line N, so that the third capacitor C5 can store electric energy.

After the voltage of the third capacitor C5 reaches a stable state, the first alternating current is output through an inverter H-bridge composed of a seventeenth switching tube B1, an eighteenth switching tube B2, a nineteenth switching tube B3 and a twentieth switching tube B4. The seventeenth switching tube B1 and the twentieth switching tube B4 are controlled to be turned on and off simultaneously, the eighteenth switching tube B2 and the nineteenth switching tube B3 are controlled to be turned on and off simultaneously, and when the seventeenth switching tube B1 and the twentieth switching tube B4 are turned on and the eighteenth switching tube B2 and the nineteenth switching tube B3 are turned off, the power flow direction can be understood as: the third capacitor C5, the seventeenth switching tube B1, the fourth capacitor C1, the first winding n1, the fifth inductor L1, the twentieth switching tube B4 and the third capacitor C5; when the eighteenth switching tube B2 and the nineteenth switching tube B3 are turned on and the seventeenth switching tube B1 and the twentieth switching tube B4 are turned off, the power flow direction can be understood as: the third capacitor C5- & gt nineteenth switching tube B3- & gt fifth inductor L1- & gt first winding n 1- & gt fourth capacitor C1- & gt eighteenth switching tube B2- & gt third capacitor C5, in the process, the first winding n1 of the isolation conversion unit 40 is provided with a first alternating current, so that the second winding n2 of the isolation conversion unit 40 can induce a second alternating current, isolation conversion is realized, and the safety of a charge-discharge circuit is improved.

In the embodiment shown in fig. 2, the third leg of the motor control unit 20 and the first leg of the generator control unit 30 constitute a rectifying H-bridge, and the ninth switching tube M5, the tenth switching tube M2, the eleventh switching tube G1 and the twelfth switching tube G4 operate in an AC-DC controllable rectifying state. The source electrode of the ninth switching tube M5 and the drain electrode of the tenth switching tube M2 in the third bridge arm of the motor control unit 20 are respectively connected with one end of the third switch S3, and the source electrode of the eleventh switching tube G1 and the drain electrode of the twelfth switching tube G4 in the first bridge arm of the generator control unit 30 are respectively connected with one end of the fourth switch S4, so as to realize multiplexing of the ninth switching tube M5, the tenth switching tube M2, the eleventh switching tube G1 and the twelfth switching tube G4. The ninth switching tube M5 and the twelfth switching tube G4 are controlled to be turned on and off simultaneously, and the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned on and off simultaneously. When the ninth switching tube M5 and the twelfth switching tube G4 are turned on, the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned off, and when the ninth switching tube M5 and the twelfth switching tube G4 are turned off, the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned on, and the second alternating current output by the isolation conversion unit 40 is converted into the first direct current and output. It is understood that when the seventeenth switching tube B1 and the twentieth switching tube B4 are turned on, the tenth switching tube M2 and the eleventh switching tube G1 are also turned on, and when the eighteenth switching tube B2 and the nineteenth switching tube B3 are turned on, the ninth switching tube M5 and the twelfth switching tube G4 are also turned on. In the embodiment shown in fig. 2, since the switching tubes in the first and second arms of the motor control unit 20 and the second and third arms of the generator control unit 30 do not participate in forming the rectifier H-bridge, the fifth switching tube M1, the sixth switching tube M4, the seventh switching tube M3, the eighth switching tube M6, the thirteenth switching tube G3, the fourteenth switching tube G6, the fifteenth switching tube G5, and the sixteenth switching tube G2 can be controlled to remain turned off when the electric vehicle is operated in the ac charging mode.

It should be noted that the arrow in fig. 2 is an indication of the power flow direction in the state where the live line L is positive and the neutral line N is negative. And in the state that the live wire L is negative and the zero wire N is positive, the twenty-sixth switching tube O2 is controlled to be turned off, and the twenty-fifth switching tube O5 is controlled to be turned on. Further, the twenty-first switching tube O1 and the twenty-second switching tube O4 are controlled to be alternately turned on, the twenty-third switching tube O3 and the twenty-fourth switching tube O6 are controlled to be alternately turned on and off in a certain period when the twenty-third switching tube O3 is delayed than the twenty-first switching tube O1, and the twenty-fourth switching tube O6 is controlled to be turned on and off in a certain period when the twenty-second switching tube O4 is delayed. When the twenty-first switching tube O1 and the twenty-third switching tube O3 are turned on and the twenty-second switching tube O4 and the twenty-fourth switching tube O6 are turned off, the power flow direction can be understood as: the zero line n→the twenty-fifth switching tube O5→the twenty-first switching tube O1→the third inductor L5→the live wire L, and the zero line n→the twenty-fifth switching tube O5→the twenty-third switching tube O3→the fourth inductor L6→the live wire L, in the process, the third inductor L5 and the fourth inductor L6 can be charged so that the third inductor L5 and the fourth inductor L6 can store electric energy. When the twenty-first switching tube O1 and the twenty-third switching tube O3 are turned off and the twenty-second switching tube O4 and the twenty-fourth switching tube O6 are turned on, the power flow direction can be understood as: the third capacitor C5 can be charged in the process of the third inductor L5, the live wire L, the zero line N, the twenty-fifth switching tube O5, the third capacitor C5, the twenty-second switching tube O4, the third inductor L5, the fourth inductor L6, the live wire L, the zero line N, the twenty-fifth switching tube O5, the third capacitor C5, the second twenty-fourth switching tube O6 and the fourth inductor L6, so that the third capacitor C5 can store electric energy.

In some embodiments of the present invention, the isolation conversion unit 40 also performs AC-DC isolation conversion on the first alternating current, outputting a second direct current to charge a battery unit or power a low voltage device in the electric vehicle.

In this way, the number of switching tubes in the charge-discharge circuit of the electric vehicle can be further saved, and the low-voltage second direct current can be output when the electric vehicle is operated in the alternating-current charging mode. It can be understood that in the related art, 4 switching tubes are needed to form an H-bridge to output the second direct current to charge the low-voltage battery unit or power the low-voltage device in the electric vehicle, and in the application, the 4 switching tubes are not needed to be additionally arranged, so that the second direct current is output to charge the low-voltage device or power the low-voltage battery unit in the electric vehicle through the isolation conversion unit 40. In addition, in the foregoing embodiment, the power battery unit 80 is charged by multiplexing part of the switching tubes in the motor control unit 20 and the generator control unit 30, that is, 4 switching tubes are saved again on the basis of 4 switching tubes being saved, 8 switching tubes can be saved in total, and the weight and the volume of the charge-discharge circuit of the electric vehicle can be reduced to a greater extent.

Specifically, when the low-voltage output positive electrode 46 is connected to the positive electrode of the low-voltage battery unit and the low-voltage output negative electrode 48 is connected to the negative electrode of the low-voltage battery unit, the second dc power output from the isolation conversion unit 40 can charge the low-voltage battery unit in the electric vehicle. When the low voltage output positive electrode 46 is connected to the positive electrode of the low voltage device and the low voltage output negative electrode 48 is connected to the negative electrode of the low voltage device, the second dc power output from the isolation conversion unit 40 can charge the device in the electric vehicle. The low voltage output positive electrode 46 and the low voltage output negative electrode 48 may be connected in parallel to the sixth capacitor C6, and the sixth capacitor C6 may be capable of stabilizing the voltage of the output second direct current.

In this embodiment, the isolation transforming unit 40 may be understood as a transformer having two sets of secondary windings, the first winding n1 is a primary winding of the transformer, the second winding n2 is one set of secondary windings of the transformer, and the third winding n3 is the other set of secondary windings of the transformer.

In the embodiment shown in fig. 2, the battery cell is a 12V battery cell (BAT). The low-voltage device may be a device for current charge control in an electric vehicle, or may be another low-voltage device such as a speaker, an indicator lamp, an atmosphere lamp, etc. of the electric vehicle, which is not limited herein.

In some embodiments of the present invention, the bidirectional DC/DC conversion unit 10 is further configured to perform step-down control on the first direct current to output the stepped-down first direct current to the power battery unit 80 for charging.

In this way, the applicability of the charge/discharge circuit of the electric vehicle is improved, and the power battery cells 80 of different specifications can be charged.

Specifically, when the electric vehicle is operated in the ac charging mode, the first switching tube Q1 and the second switching tube Q2 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on, the third switching tube Q3 and the fourth switching tube Q4 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on and off with a certain period of time delay than the first switching tube Q1, and the fourth switching tube Q4 is controlled to be turned on and off with a certain period of time delay than the second switching tube Q2, so that the first switching tube Q1, the second switching tube Q2, the third switching tube Q3 and the fourth switching tube Q4 are operated in the Buck circuit mode to perform step-down control on the first direct current and output the step-down first direct current to the power battery unit 80 for charging. It will be appreciated that the degree of step-down of the first direct current may be controlled by adjusting the duty cycle of the PWM waveform.

Referring to fig. 3, in some embodiments of the present invention, when the electric vehicle is operated in the ac discharging mode, the first controllable switch unit 60 is opened, the second controllable switch unit 70 is closed, any one phase of bridge arm in the motor control unit 20 and any one phase of bridge arm in the generator control unit 30 form an inverted H-bridge, the dc power provided by the power battery unit 80 is inverted into a third ac power, the isolation conversion unit 40 performs isolation conversion on the third ac power, outputs a fourth ac power, and the OBC control unit 50 rectifies and inverts the fourth ac power and provides the fourth ac power to the external ac charging and discharging device.

In this way, by multiplexing part of the switching tubes in the motor control unit 20 and the generator control unit 30, the supply of electric power to the external ac charging and discharging device is realized, and further, the ac power grid discharge (V2G) by the electric vehicle, the ac power discharge (V2V) by the electric vehicle, or the load (V2L) by the electric vehicle can be realized.

Specifically, in the embodiment shown in fig. 3, the third leg of motor control unit 20 and the first leg of generator control unit 30 constitute an inverter H-bridge. The source electrode of the ninth switching tube M5 and the drain electrode of the tenth switching tube M2 in the third bridge arm of the motor control unit 20 are respectively connected with one end of the third switch S3, and the source electrode of the eleventh switching tube G1 and the drain electrode of the twelfth switching tube G4 in the first bridge arm of the generator control unit 30 are respectively connected with one end of the fourth switch S4, so as to realize multiplexing of the ninth switching tube M5, the tenth switching tube M2, the eleventh switching tube G1 and the twelfth switching tube G4. The ninth switching tube M5 and the twelfth switching tube G4 are controlled to be turned on and off simultaneously, and the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned on and off simultaneously. When the ninth switching tube M5 and the twelfth switching tube G4 are turned on, the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned off, and when the ninth switching tube M5 and the twelfth switching tube G4 are turned off, the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned on, and the switching is alternately performed, so that the direct current power supplied by the power battery unit 80 is inverted into the third alternating current, the third alternating current flows through the second winding n2 of the isolation change unit, and the first winding n1 of the isolation change unit 40 can induce and output the fourth alternating current. In the embodiment shown in fig. 3, since the switching tubes in the first and second arms of the motor control unit 20 and the second and third arms of the generator control unit 30 do not participate in the formation of the inverter H-bridge, the fifth switching tube M1, the sixth switching tube M4, the seventh switching tube M3, the eighth switching tube M6, the thirteenth switching tube G3, the fourteenth switching tube G6, the fifteenth switching tube G5, and the sixteenth switching tube G2 can be controlled to remain turned off when the electric vehicle is operated in the ac discharge mode.

The seventeenth switching tube B1, the eighteenth switching tube B2, the nineteenth switching tube B3 and the twentieth switching tube B4 of the OBC control unit 50 form a rectifying H-bridge, and the seventeenth switching tube B1, the eighteenth switching tube B2, the nineteenth switching tube B3 and the twentieth switching tube B4 are controlled to operate in an AC-DC controllable rectifying state, so as to rectify the fourth alternating current output by the isolation conversion unit 40, and establish a direct current voltage on the third capacitor C5. The twenty-first switching tube O1, the twenty-second switching tube O4, the twenty-third switching tube O3, the twenty-fourth switching tube O6, the twenty-fifth switching tube O5, and the twenty-sixteen switching tube O2 of the OBC control unit 50 are controlled to operate in a DC-AC inversion state to supply electric power to the external AC charging and discharging device.

Further, when the twenty-first switching tube O1, the twenty-third switching tube O3, and the twenty-sixth switching tube O2 are turned on, the power flow direction can be understood as: one end of the third capacitor C5, the twenty-first switching tube O1, the third inductor L5, the fire wire L, the zero line N, the twenty-first switching tube O2, the other end of the third capacitor C5, and one end of the third capacitor C5, the twenty-third switching tube O3, the fourth inductor L6, the fire wire L, the zero line N, the twenty-first switching tube O2, the other end of the third capacitor C5, wherein in the process, the fire wire L is positive, and the zero line N is negative; when the twenty-second switching tube O4, the twenty-fourth switching tube O6, and the twenty-fifth switching tube O5 are turned on, the power flow direction can be understood as: one end of the third capacitor C5, the twenty-fifth switching tube O5, the zero line N, the fire wire L, the third inductor L5, the twenty-second switching tube O4, the other end of the third capacitor C5, and one end of the third capacitor C5, the twenty-fifth switching tube O5, the zero line N, the fire wire L, the fourth inductor L6, the twenty-fourth switching tube O6, the other end of the third capacitor C5, wherein in the process, the fire wire L is negative, and the zero line N is positive. Thus, ac output is realized.

In some embodiments of the present invention, the isolation conversion unit 40 also performs AC-DC isolation conversion on the third alternating current, outputting a second direct current to charge a battery unit or power a low voltage device in the electric vehicle.

Thus, the electric isolation between the power battery unit 80 and the low-voltage battery unit and the low-voltage device is realized, which is beneficial to improving the safety of the charge-discharge circuit.

In some embodiments of the present invention, the bidirectional DC/DC conversion unit 10 is further configured to boost-control the DC power supplied from the power battery unit 80, so as to output the boosted DC power to the inverter H-bridge for inversion.

In this way, appropriate electric power can be supplied to the external ac charge-discharge device.

Specifically, when the electric vehicle is operated in the ac discharging mode, the first switching tube Q1 and the second switching tube Q2 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on, the third switching tube Q3 and the fourth switching tube Q4 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on and off in a certain period when the third switching tube Q3 is delayed than the first switching tube Q1, and the fourth switching tube Q4 is controlled to be turned on and off in a certain period when the second switching tube Q2 is delayed, so that the first switching tube Q1, the second switching tube Q2, the third switching tube Q3 and the fourth switching tube Q4 are operated in the staggered parallel Boost circuit mode to Boost the DC power supply provided by the power battery unit 80 and output the boosted DC power supply to the inverter H bridge for inversion. It will be appreciated that the degree of boost of the dc power supply may be controlled by adjusting the duty cycle of the PWM waveform.

Further, the first switching tube Q1 and the second switching tube Q2 are controlled to be alternately turned on, the third switching tube Q3 and the fourth switching tube Q4 are controlled to be alternately turned on and off in a certain period when the third switching tube Q3 is delayed than the first switching tube Q1, and the fourth switching tube Q4 is controlled to be turned on and off in a certain period when the fourth switching tube Q4 is delayed than the second switching tube Q2. When the second switching tube Q2 and the fourth switching tube Q4 are turned on and the first switching tube Q1 and the third switching tube Q3 are turned off, the power flow direction can be understood as: the positive terminal of the power battery unit 80→the first inductor L3→the second switching tube q2→the negative terminal of the power battery unit 80, and the positive terminal of the power battery unit 80→the second inductor l4→the fourth switching tube q4→the negative terminal of the power battery unit 80, in this process, the first inductor L3 and the second inductor L4 may be charged so that the first inductor L3 and the second inductor L4 can store electric energy. When the second switching tube Q2 and the fourth switching tube Q4 are turned off and the first switching tube Q1 and the third switching tube Q3 are turned on, the first inductor L3 and the second inductor L4 release electric energy and are overlapped with the voltage of the power battery unit 80, so that the boosting effect is achieved.

Referring to fig. 4, in some embodiments of the present invention, when the electric vehicle is operated in a driving mode, the first controllable switch unit 60 is closed, the second controllable switch unit 70 is opened, the motor control unit 20 drives and controls the driving motor of the electric vehicle according to the DC power provided by the power battery unit 80, the generator control unit 30 operates in a DC-AC inversion state or an AC-DC controllable rectification state, the OBC control unit 50 inverts the DC power provided by the power battery unit 80 into an AC power, the isolation conversion unit 40 performs AC-DC isolation conversion on the AC power, and outputs a second DC power to charge the battery unit or power a low voltage device in the electric vehicle.

In this way, by multiplexing a part of the switching tubes in the OBC control unit 50, electrical isolation between the power battery unit 80 and the low-voltage battery unit and the low-voltage device is achieved, which is beneficial to improving the safety of the charge-discharge circuit.

Specifically, when the electric vehicle is operating in the running mode, in some embodiments, the fifth switching tube M1, the seventh switching tube M3, and the tenth switching tube M2 in the motor control unit 20 are turned on and off simultaneously, the sixth switching tube M4, the eighth switching tube M6, and the ninth switching tube M5 in the motor control unit 20 are turned on and off simultaneously, and when the fifth switching tube M1, the seventh switching tube M3, and the tenth switching tube M2 are turned on, the sixth switching tube M4, the eighth switching tube M6, and the ninth switching tube M5 are turned off, and when the fifth switching tube M1, the seventh switching tube M3, and the tenth switching tube M2 are turned off, the sixth switching tube M4, the eighth switching tube M6, and the ninth switching tube M5 are turned on, thereby performing drive control of the drive motor in the electric vehicle according to the direct current power supplied from the power battery unit 80.

When the generator control unit 30 operates in the DC-AC inversion state, the generator control unit 30 may boost the driving motor in the electric vehicle according to the direct current power supplied from the power battery unit 80, thereby increasing the output of the driving motor. When the generator control unit 30 is operating in the AC-DC controlled rectification state, the generator control unit 30 may perform energy recovery through coasting feedback.

When the electric vehicle is operated in the traveling mode, the twenty-first switching tube O1, the twenty-second switching tube O4, the twenty-third switching tube O3, the twenty-fourth switching tube O6, the twenty-fifth switching tube O5, the twenty-sixteen switching tube O2, the third inductance L5, and the fourth inductance L6 in the OBC control unit 50 are not operated, and the seventeenth switching tube B1, the eighteenth switching tube B2, the nineteenth switching tube B3, and the twentieth switching tube B4 in the OBC control unit 50 are operated in the DC-AC inversion state, thereby inverting the direct current power supplied from the power battery unit 80 to the alternating current power. When an ac power source acts on the first winding n1 of the isolation conversion unit 40, a corresponding ac power can be induced on the third winding n3 of the isolation conversion unit 40, and then a second dc power is output after rectification through the first diode D1 and the second diode D2.

In some embodiments of the present invention, the bidirectional DC/DC conversion unit 10 is further configured to boost-control the direct-current power supplied from the power battery unit 80, so that the motor control unit 20 performs drive control of the drive motor in the electric vehicle according to the boosted direct-current power.

Therefore, the driving motor can be provided with proper electric energy, and the normal operation of the driving motor is ensured.

Specifically, when the electric vehicle is operated in the running mode, the first switching tube Q1 and the second switching tube Q2 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on, the third switching tube Q3 and the fourth switching tube Q4 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on and off with a certain period of time delay than the first switching tube Q1, and the fourth switching tube Q4 is controlled to be turned on and off with a certain period of time delay than the second switching tube Q2, so that the first switching tube Q1, the second switching tube Q2, the third switching tube Q3 and the fourth switching tube Q4 are operated in the staggered parallel Boost circuit mode to perform Boost control on the direct current power supply provided by the power battery unit 80 and output the boosted direct current power supply to the motor control unit 20. It will be appreciated that the degree of boost of the dc power supply may be controlled by adjusting the duty cycle of the PWM waveform.

Referring to fig. 5, in some embodiments of the present invention, when both the first controllable switch unit 60 and the second controllable switch unit 70 are closed, the OBC control unit 50 inverts the DC power provided by the power battery unit 80 and provides the DC power to the external AC charging and discharging device, any one phase of bridge arm in the motor control unit 20 and any one phase of bridge arm in the generator control unit 30 form an inverted H bridge, the DC power provided by the power battery unit 80 is inverted into a third AC power, the isolation conversion unit 40 performs AC-DC isolation conversion on the third AC power, and outputs the second DC power to charge the battery unit or power the low voltage device in the electric vehicle.

In this way, single-phase non-isolated ac discharge can be performed between the power battery unit 80 and the external ac charging and discharging device, and at the same time, the power battery unit 80 can charge the battery unit or power the low-voltage device in the electric vehicle in an isolated manner.

Specifically, in the embodiment shown in fig. 5, the third leg of the motor control unit 20 and the first leg of the generator control unit 30 constitute an inverter H-bridge. The source electrode of the ninth switching tube M5 and the drain electrode of the tenth switching tube M2 in the third bridge arm of the motor control unit 20 are respectively connected with one end of the third switch S3, and the source electrode of the eleventh switching tube G1 and the drain electrode of the twelfth switching tube G4 in the first bridge arm of the generator control unit 30 are respectively connected with one end of the fourth switch S4, so as to realize multiplexing of the ninth switching tube M5, the tenth switching tube M2, the eleventh switching tube G1 and the twelfth switching tube G4. The ninth switching tube M5 and the twelfth switching tube G4 are controlled to be turned on and off simultaneously, and the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned on and off simultaneously. When the ninth switching tube M5 and the twelfth switching tube G4 are turned on, the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned off, and when the ninth switching tube M5 and the twelfth switching tube G4 are turned off, the tenth switching tube M2 and the eleventh switching tube G1 are controlled to be turned on, so that the inversion of the direct current power supplied by the power battery unit 80 into the third alternating current is realized, the third alternating current flows through the second winding n2 of the isolation change unit, and the third winding n3 of the isolation change unit 40 can induce the corresponding alternating current and output the second direct current after being rectified by the first diode D1 and the second diode D2. In the embodiment shown in fig. 5, since the switching tubes in the first and second arms of the motor control unit 20 and the second and third arms of the generator control unit 30 do not participate in the formation of the inverter H-bridge, the fifth switching tube M1, the sixth switching tube M4, the seventh switching tube M3, the eighth switching tube M6, the thirteenth switching tube G3, the fourteenth switching tube G6, the fifteenth switching tube G5, and the sixteenth switching tube G2 can be controlled to remain turned off when the electric vehicle is operated in the ac discharge mode.

When both the first controllable switching unit 60 and the second controllable switching unit 70 are turned on, the seventeenth switching tube B1, the eighteenth switching tube B2, the nineteenth switching tube B3, and the twentieth switching tube B4 are controlled to remain turned off, and the twenty first switching tube O1, the twenty second switching tube O4, the twenty third switching tube O3, the twenty fourth switching tube O6, the twenty fifth switching tube O5, and the twenty sixteen switching tube O2 are controlled to operate in a DC-AC inversion state to invert the direct current power supplied from the power battery unit 80 and supply the inverted power to the external AC charging and discharging device.

Therefore, proper electric energy can be provided for the low-voltage battery unit or the low-voltage device, and normal operation of the low-voltage battery unit or the low-voltage device is ensured.

Specifically, the first switching tube Q1 and the second switching tube Q2 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on, the third switching tube Q3 and the fourth switching tube Q4 of the bidirectional DC/DC conversion unit 10 are controlled to be alternately turned on and off in a certain period after the third switching tube Q3 is delayed than the first switching tube Q1, and the fourth switching tube Q4 is controlled to be turned on and off in a certain period after the second switching tube Q2 is delayed, so that the first switching tube Q1, the second switching tube Q2, the third switching tube Q3 and the fourth switching tube Q4 work in a staggered parallel Boost circuit mode to Boost the direct current power supply provided by the power battery unit 80 and output the boosted direct current power supply to the inverter H bridge for inversion. It will be appreciated that the degree of boost of the dc power supply may be controlled by adjusting the duty cycle of the PWM waveform.

Further, the first switching tube Q1 and the second switching tube Q2 are controlled to be alternately turned on, the third switching tube Q3 and the fourth switching tube Q4 are controlled to be alternately turned on and off in a certain period when the third switching tube Q3 is delayed than the first switching tube Q1, and the fourth switching tube Q4 is controlled to be turned on and off in a certain period when the fourth switching tube Q4 is delayed than the second switching tube Q2. When the second switching tube Q2 and the fourth switching tube Q4 are turned on and the first switching tube Q1 and the third switching tube Q3 are turned off, the power flow direction can be understood as: the positive terminal of the power battery unit 80→the first inductor L3→the second switching tube q2→the negative terminal of the power battery unit 80, and the positive terminal of the power battery unit 80→the second inductor l4→the fourth switching tube q4→the negative terminal of the power battery unit 80, in this process, the first inductor L3 and the second inductor L4 may be charged so that the first inductor L3 and the second inductor L4 can store electric energy. When the second switching tube Q2 and the fourth switching tube Q4 are turned off and the first switching tube Q1 and the third switching tube Q3 are turned on, the first inductor L3 and the second inductor L4 release electric energy, and therefore boosting effect is achieved.

Referring to fig. 6, in some embodiments of the present invention, when the first controllable switch unit 60 is closed and the second controllable switch unit 70 is opened, the OBC control unit 50 performs inverter control on the DC power supplied from the power battery unit 80, and outputs a first AC power and a second AC power, respectively, where the first AC power is used for being supplied to an external AC charging and discharging device, and the isolation conversion unit 40 performs AC-DC isolation conversion on the second AC power, and outputs a second DC power to charge a low-voltage battery unit or a low-voltage device in the electric vehicle.

Specifically, in order to achieve normal operation of the low-voltage battery unit charging or the low-voltage device during discharging of the electric vehicle, the bidirectional DC/DC conversion unit 10, the motor control unit 20, and the generator control unit 30 do not operate.

The twenty-first switching tube O1, the twenty-second switching tube O4, the twenty-third switching tube O3, the twenty-fourth switching tube O6, the twenty-fifth switching tube O5, and the twenty-sixteen switching tube O2 of the OBC control unit 50 are controlled to operate in a DC-AC inversion state to invert the direct current power supplied from the power battery unit 80 to obtain a first alternating current power, and the first alternating current power is supplied to the external alternating current charge-discharge device.

The seventeenth, eighteenth, nineteenth and twentieth switching tubes B1, B2, B3 and B4 of the OBC control unit 50 are controlled to operate in a DC-AC inversion state to invert the direct current power supplied from the power battery unit 80 to obtain a second alternating current power, the second alternating current power is applied to the first winding n1 of the isolation control unit, the third winding n3 of the isolation control unit is capable of inducing an alternating current and outputting a second direct current after rectifying through the first and second diodes D1 and D2.

It should be noted that in some embodiments, OBC control unit 50 may be a single-phase OBC control unit and charge-discharge terminal 90 may be a single-phase charge-discharge terminal (as shown in fig. 1); in some embodiments, the OBC control unit 50 may be a three-phase OBC control unit, and the charge/discharge terminals 90 may be three-phase charge/discharge terminals (as shown in fig. 7), which is not limited herein.

It will be appreciated that when the OBC control unit 50 is a single-phase OBC control unit and the charge/discharge terminal 90 is a single-phase charge/discharge terminal, the ac power provided by the external ac charge/discharge device may be 220V single-phase ac, or 110V single-phase ac, 200V single-phase ac or other single-phase ac, which is not limited herein. When the OBC control unit 50 is a three-phase OBC control unit and the charge and discharge terminal 90 is a three-phase charge and discharge terminal, the ac power supplied from the external ac charge and discharge device may be 380V three-phase ac or other three-phase ac, which is not limited herein.

Referring to fig. 1 and fig. 7 together, it can be seen that the three-phase OBC control unit is equivalent to adding a set of bridge arms and an inductor based on the single-phase OBC control unit, that is, adding the twenty-seven switching tube O7, the twenty-eight switching tube O8 and the seventh inductor L7. The bidirectional DC/DC conversion unit, the motor control unit, the generator control unit, the isolation conversion unit, the first controllable switch unit and the second controllable switch unit in the charge-discharge circuit corresponding to the three-phase OBC control unit are the same as the bidirectional DC/DC conversion unit, the motor control unit, the generator control unit, the isolation conversion unit, the first controllable switch unit and the second controllable switch unit of the charge-discharge circuit corresponding to the single-phase OBC control unit, and the two charge-discharge circuits can realize the control method of the charge-discharge circuit of the electric vehicle.

The invention proposes an electric vehicle comprising a charge-discharge circuit of an electric vehicle according to any of the embodiments described above.

Specifically, electric vehicles include, but are not limited to, electric-only vehicles, hybrid electric vehicles.

It should be noted that the above explanation of the implementation and advantageous effects of the charge-discharge circuit of the electric vehicle is also applicable to the electric vehicle of the present embodiment, and is not developed in detail here to avoid redundancy.

Referring to fig. 8, the present invention provides a control method of a charge-discharge circuit of an electric vehicle according to any of the above embodiments, the control method comprising:

s11: determining an operating mode of the electric vehicle;

s13: when the working mode of the electric vehicle is an alternating current charging and discharging mode, the switching states of the first controllable switching unit and the second controllable switching unit are configured, so that at least part of switching tubes in the bidirectional DC/DC conversion unit, the motor control unit, the generator control unit and the OBC control unit form part of a charging and discharging loop, and energy isolation transmission between the power battery unit and external alternating current charging and discharging equipment is realized.

Specifically, the operation modes of the electric vehicle may include an ac charge-discharge mode and a travel mode, and the ac charge-discharge mode may include an ac charge mode and an ac discharge mode.

It should be noted that the above explanation of the implementation and advantageous effects of the charge/discharge circuit of the electric vehicle is also applicable to the control method of the charge/discharge circuit of the electric vehicle of the present embodiment, and is not developed in detail here to avoid redundancy.

It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, for example, may be considered as a ordered listing of executable instructions for implementing logical functions, and may 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). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may 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 is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means 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 present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Furthermore, the terms "first," "second," and the like, as used in embodiments of the present invention, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or as implying any particular number of features in the present embodiment. Thus, a feature of an embodiment of the invention that is defined by terms such as "first," "second," etc., may explicitly or implicitly indicate that at least one such feature is included in the embodiment. In the description of the present invention, the word "plurality" means at least two or more, for example, two, three, four, etc., unless explicitly defined otherwise in the embodiments.

In the present invention, unless explicitly stated or limited otherwise in the examples, the terms "mounted," "connected," and "fixed" as used in the examples should be interpreted broadly, e.g., the connection may be a fixed connection, may be a removable connection, or may be integral, and it may be understood that the connection may also be a mechanical connection, an electrical connection, etc.; of course, it may be directly connected, or indirectly connected through an intermediate medium, or may be in communication with each other, or in interaction with each other. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific embodiments.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. A charge-discharge circuit of an electric vehicle, comprising: the electric vehicle is characterized by comprising a bidirectional DC/DC conversion unit, a motor control unit, a generator control unit, an isolation conversion unit, an OBC control unit, a first controllable switch unit and a second controllable switch unit, wherein the bidirectional DC/DC conversion unit is connected to a power battery unit, a direct current end of the OBC control unit is connected to the power battery unit through the first controllable switch unit, a first alternating current end of the OBC control unit is connected to an external alternating current charging and discharging device, a second alternating current end of the OBC control unit is connected with the isolation conversion unit, the isolation conversion unit is further connected with the motor control unit and the generator control unit through the second controllable switch unit respectively, and when the electric vehicle works in an alternating current charging and discharging mode, at least part of switch tubes in the bidirectional DC/DC conversion unit, the motor control unit, the generator control unit and the OBC control unit form a part of a charging and discharging loop, so that the battery unit and the external charging and discharging device can be isolated.

2. The charge/discharge circuit of an electric vehicle according to claim 1, wherein when the electric vehicle is operated in an ac charging mode, the first controllable switch unit is turned off, the second controllable switch unit is turned on, the OBC control unit rectifies and PFC-corrects an ac power supply provided by the external ac charging/discharging device, and then inverts the rectified ac power supply to output a first ac power, the isolation conversion unit performs an isolation conversion on the first ac power to output a second ac power, any one phase of a bridge arm of the motor control unit and any one phase of a bridge arm of the generator control unit form a rectified H-bridge, rectify the second ac power, and output a first dc power to charge the power battery unit.

3. The charge-discharge circuit of an electric vehicle according to claim 2, wherein the isolation conversion unit further performs AC-DC isolation conversion on the first alternating current, and outputs a second direct current to charge a low-voltage device or charge a battery unit in the electric vehicle.

4. The charge-discharge circuit of an electric vehicle according to claim 2, wherein the bidirectional DC/DC conversion unit is further configured to perform step-down control on the first direct current to output the stepped-down first direct current to the power battery unit for charging.

5. The charge/discharge circuit of an electric vehicle according to claim 1, wherein when the electric vehicle is operated in an ac discharge mode, the first controllable switch unit is turned off, the second controllable switch unit is turned on, an inverter H-bridge is formed by any one phase of bridge arm in the motor control unit and any one phase of bridge arm in the generator control unit, a dc power source provided by the power battery unit is inverted into a third ac power, the isolation conversion unit performs isolation conversion on the third ac power, outputs a fourth ac power, and the OBC control unit rectifies and inverts the fourth ac power and supplies the fourth ac power to the external ac charge/discharge device.

6. The charge-discharge circuit of an electric vehicle according to claim 5, wherein the isolation conversion unit further performs AC-DC isolation conversion on the third alternating current, and outputs a second direct current to charge a low-voltage device or charge a battery unit in the electric vehicle.

7. The charge-discharge circuit of claim 5, wherein the bidirectional DC/DC conversion unit is further configured to boost-control a direct-current power supply provided by the power battery unit to output the boosted direct-current power supply to the inverter H-bridge for inversion.

8. The charge-discharge circuit of an electric vehicle according to claim 1, wherein when the electric vehicle is operated in a running mode, the first controllable switch unit is turned on, the second controllable switch unit is turned off, the motor control unit performs drive control on a driving motor in the electric vehicle according to a direct current power supply provided by the power battery unit, the generator control unit operates in a DC-AC inversion state or an AC-DC controllable rectification state, the OBC control unit inverts a direct current power supply provided by the power battery unit into an alternating current power supply, and the isolation conversion unit performs AC-DC isolation conversion on the alternating current power supply and outputs a second direct current power to charge a battery unit or a low-voltage device in the electric vehicle.

9. The charge-discharge circuit of an electric vehicle according to claim 8, wherein the bidirectional DC/DC conversion unit is further configured to boost-control a direct-current power supply provided by the power battery unit, so that the motor control unit performs drive control of a drive motor in the electric vehicle according to the boosted direct-current power supply.

10. The charge-discharge circuit of any one of claims 1 to 9, wherein the first controllable switch unit includes a first switch and a second switch, the second controllable switch unit includes a third switch and a fourth switch, wherein one end of the first switch is connected to the positive terminal of the power battery unit, the other end of the first switch is connected to the positive terminal of the OBC control unit, one end of the second switch is connected to the negative terminal of the power battery unit, the other end of the second switch is connected to the negative terminal of the OBC control unit, one end of the third switch is connected to the midpoint of any one phase leg of the motor control unit, the other end of the third switch is connected to the first ac terminal of the isolation conversion unit, one end of the fourth switch is connected to the midpoint of any one phase leg of the generator control unit, and the other end of the fourth switch is connected to the second ac terminal of the isolation conversion unit.

11. The electric vehicle charge-discharge circuit of claim 10, wherein the OBC control unit includes a three-phase bridge and an H-bridge, wherein an ac end of the three-phase bridge is connected to an external ac charge-discharge device as a first ac end of the OBC control unit, an upper bridge arm dc end of the three-phase bridge is used as a dc positive end of the OBC control unit, a lower bridge arm dc end of the three-phase bridge is used as a dc negative end of the OBC control unit, an ac end of the H-bridge is connected to the isolation conversion unit as a second ac end of the OBC control unit, an upper bridge arm dc end of the H-bridge is connected to an upper bridge arm dc end of the three-phase bridge, and a lower bridge arm dc end of the H-bridge is connected to a lower bridge arm dc end of the three-phase bridge.

12. The electric vehicle charging and discharging circuit according to claim 10, wherein the isolation conversion unit includes an isolation transformer, a fifth inductance, a sixth inductance, a fourth capacitance, a fifth capacitance, a first diode, and a second diode, the isolation transformer includes a first winding, a second winding, and a third winding, wherein the same-name end of the first winding is connected to a second ac end of the OBC control unit through the fifth inductance, the different-name end of the first winding is connected to another second ac end of the OBC control unit through the fourth capacitance, the same-name end of the second winding is connected to the third switch through the sixth inductance, the different-name end of the second winding is connected to the fourth switch through the fifth capacitance, the same-name end of the third winding is connected to a positive electrode of the first diode, a negative electrode of the first diode is used as a low-voltage output positive electrode of the isolation conversion unit, the different-name end of the third winding is connected to a negative electrode of the second diode is used as a low-voltage output of the low-voltage conversion unit, and the negative electrode of the second winding is used as a low-voltage output of the low-voltage power supply unit.

13. The charge-discharge circuit of an electric vehicle according to claim 1, wherein when the first controllable switch unit and the second controllable switch unit are both closed, the OBC control unit inverts a direct current power supply provided by the power battery unit and supplies the inverted direct current power supply to the external alternating current charge-discharge device, any one phase of bridge arm in the motor control unit and any one phase of bridge arm in the generator control unit form an inverted H bridge, the direct current power supply provided by the power battery unit is inverted into a third alternating current, and the isolation conversion unit performs AC-DC isolation conversion on the third alternating current and outputs a second direct current to charge a low-voltage battery unit or supply power to a low-voltage device in the electric vehicle.

14. The charge-discharge circuit of claim 13, wherein the bidirectional DC/DC conversion unit is further configured to boost-control a direct-current power supply provided by the power battery unit to output the boosted direct-current power supply to the inverter H-bridge for inversion.

15. The charge-discharge circuit of an electric vehicle according to claim 1, wherein when the first controllable switch unit is turned on and the second controllable switch unit is turned off, the OBC control unit performs inversion control on the DC power supplied from the power battery unit, and outputs a first AC power and a second AC power, respectively, the first AC power being used for being supplied to the external AC charge-discharge device, and the isolation conversion unit performs AC-DC isolation conversion on the second AC power, and outputs a second DC power for charging or supplying a low-voltage device to the battery unit in the electric vehicle.

16. An electric vehicle characterized by comprising the charge-discharge circuit of an electric vehicle according to any one of claims 1-15.

17. A control method of the charge-discharge circuit of an electric vehicle according to any one of claims 1 to 15, characterized by comprising:

determining an operating mode of the electric vehicle;

when the working mode of the electric vehicle is an alternating current charging and discharging mode, the switching states of the first controllable switching unit and the second controllable switching unit are configured, so that at least part of switching tubes in the bidirectional DC/DC conversion unit, the motor control unit, the generator control unit and the OBC control unit form a part of a charging and discharging loop, and energy isolation transmission between the power battery unit and the external alternating current charging and discharging equipment is realized.