Charging and discharging topology circuit of electric vehicle and control method thereof

Abstract

The application provides a charging and discharging topology circuit of an electric vehicle and a control method thereof. In the circuit, an intermediate node of two switching devices in each bridge arm of a first electric bridge is connected to a primary side of a first transformer module and a primary side of a second transformer module, a secondary side of the first transformer module is connected to an intermediate node of two switching devices in each bridge arm of a second electric bridge and an intermediate node of two switching devices in a first bridge arm of a third electric bridge, a secondary side of the second transformer module is connected to an intermediate node of two switching devices in each bridge arm of the third electric bridge and an intermediate node of two switching devices in a first bridge arm of the second electric bridge, each bridge arm of the second electric bridge is connected in parallel with a second capacitor, each bridge arm of the third electric bridge is connected in parallel with a third capacitor, and the opening or closing of a plurality of switching sub-modules in a switching module determines the circuit topology of a power unit with a larger power density and a voltage adaptive power connected to a battery.

Description

Technical Field

[0001] This application relates to the field of electric vehicles, and more specifically, to a charging and discharging topology circuit for an electric vehicle and its control method. Background Technology

[0002] Charging piles are generally formed by several power modules connected in parallel, and the power module is the smallest power unit of the charging pile. With the development of power device technology, the power unit has gradually transitioned from 15kW and 20kW to 30kW and 40kW, with the power gradually increasing and the power density gradually improving.

[0003] Power modules typically consist of AC / DC converters and DC / DC converters. As the power and power density of power units gradually increase, the circuit topology needs to be adapted to the power units.

[0004] In existing power module topologies, the AC / DC section typically uses a Vienna rectifier, while the DC / DC section generally uses an LLC resonant converter. However, with increasing power, the resonant current in the LLC resonant converter used in the DC / DC section becomes too large, affecting the circuit gain, increasing losses, and decreasing power density.

[0005] Currently, there is a lack of a circuit topology that is suitable for power units with high power and power density. Summary of the Invention

[0006] The main objective of this application is to provide a charging and discharging topology circuit and its control method for electric vehicles, in order to solve the problem of the lack of a circuit topology in the prior art that is suitable for power units with large power and power density.

[0007] To achieve the above objectives, according to one aspect of this application, a charging and discharging topology circuit for an electric vehicle is provided, comprising: a first capacitor; and a DC / DC converter, comprising: a first bridge, a second bridge, a third bridge, a second capacitor, a third capacitor, a first transformer module, a second transformer module, and a switching module. Each arm of the first bridge, the second bridge, and the third bridge includes two series-connected switching devices, wherein the number of arms of the first bridge, the second bridge, and the third bridge is equal. Each arm of the first bridge is connected in parallel with the first capacitor, and the first capacitor is connected to a first side of the first bridge. An intermediate node of the two switching devices in each arm of the first bridge is connected to the primary side of the first transformer module and the primary side of the second transformer module. The secondary side of the first transformer module is connected to an intermediate node of the two switching devices in each arm of the second bridge and an intermediate node of the two switching devices in the first arm of the third bridge. The secondary side of the second transformer module is connected to... The third bridge has two intermediate nodes of two switching devices in each arm and two intermediate nodes of two switching devices in the first arm of the second bridge. Each arm of the second bridge is connected in parallel with the second capacitor, and the second capacitor is connected to the second side of the second bridge. Each arm of the third bridge is connected in parallel with the third capacitor, and the third capacitor is connected to the second side of the third bridge. The switching module is electrically connected to the second capacitor and the third capacitor respectively. The switching module is used to electrically connect to the battery. The opening or closing of multiple switching sub-modules in the switching module determines the voltage connected to the battery. The first side and the second side of any bridge are opposite sides based on multiple bridge arms. The first capacitor, the first bridge, the first transformer module, the second transformer module, and the second bridge jointly determine the voltage across the second capacitor. The first capacitor, the first bridge, the first transformer module, the second transformer module, and the third bridge jointly determine the voltage across the third capacitor.

[0008] Optionally, the first bridge, the second bridge, and the third bridge each have three arms. The switching devices in the first bridge include a bridge-one switching device and a bridge-four switching device located on the first arm, a bridge-two switching device and a bridge-five switching device located on the second arm, and a bridge-three switching device and a bridge-six switching device located on the third arm. The first transformer module includes a first single-phase transformer, a second single-phase transformer, and a third single-phase transformer. The second transformer module includes a fourth single-phase transformer, a fifth single-phase transformer, and a sixth single-phase transformer. An intermediate node of the bridge-one switching device and the bridge-four switching device is connected to the first end of the primary side of the first single-phase transformer and the first end of the primary side of the fourth single-phase transformer. An intermediate node of the two-switch device of the bridge circuit and the five-switch device of the bridge circuit is connected to the second end of the primary side of the first single-phase transformer and the first end of the primary side of the second single-phase transformer, as well as the second end of the primary side of the fourth single-phase transformer and the first end of the primary side of the fifth single-phase transformer. An intermediate node of the three-switch device of the bridge circuit and the six-switch device of the bridge circuit is connected to the second end of the primary side of the second single-phase transformer and the first end of the primary side of the third single-phase transformer, as well as the second end of the primary side of the fifth single-phase transformer and the first end of the primary side of the sixth single-phase transformer. The first end of the primary side of the first single-phase transformer and the second end of the primary side of the third single-phase transformer are connected, and the first end of the primary side of the fourth single-phase transformer and the second end of the primary side of the sixth single-phase transformer are connected.

[0009] Optionally, the switching devices in the second bridge include a bridge-1 switching device and a bridge-4 switching device located on the first bridge arm, a bridge-2 switching device and a bridge-5 switching device located on the second bridge arm, and a bridge-3 switching device and a bridge-6 switching device located on the third bridge arm. The first transformer module includes a first single-phase transformer, a second single-phase transformer, and a third single-phase transformer. An intermediate node of the bridge-1 switching device and the bridge-4 switching device is connected to the first end of the secondary side of the first single-phase transformer. An intermediate node of the bridge-2 switching device and the bridge-5 switching device is connected to the second end of the secondary side of the first single-phase transformer and the first end of the secondary side of the second single-phase transformer. An intermediate node of the bridge-3 switching device and the bridge-6 switching device is connected to the second end of the secondary side of the second single-phase transformer and the first end of the secondary side of the third single-phase transformer. The first end of the secondary side of the first single-phase transformer is connected to the second end of the secondary side of the sixth single-phase transformer.

[0010] Optionally, the switching devices in the third bridge include a three-bridge-one switching device and a three-bridge-four switching device located on the first bridge arm, a three-bridge-two switching device and a three-bridge-five switching device located on the second bridge arm, and a three-bridge-three switching device and a three-bridge-six switching device located on the third bridge arm. The first transformer module includes a first single-phase transformer, a second single-phase transformer, and a third single-phase transformer. An intermediate node of the three-bridge-one switching device and the three-bridge-four switching device is connected to the second end of the secondary side of the third single-phase transformer and the first end of the secondary side of the fourth single-phase transformer. An intermediate node of the three-bridge-two switching device and the three-bridge-five switching device is connected to the second end of the secondary side of the fourth single-phase transformer and the first end of the secondary side of the fifth single-phase transformer. An intermediate node of the three-bridge-three switching device and the three-bridge-six switching device is connected to the second end of the secondary side of the fifth single-phase transformer and the first end of the secondary side of the sixth single-phase transformer.

[0011] Optionally, the first transformer module further includes six sets of resonant capacitor-inductor modules. Each set of resonant capacitor-inductor modules includes a resonant capacitor and a resonant inductor connected in series. The six sets of resonant capacitor-inductor modules are respectively connected in series at the first end of the primary side of the first single-phase transformer, the first end of the secondary side of the first single-phase transformer, the first end of the primary side of the second single-phase transformer, the first end of the secondary side of the second single-phase transformer, the first end of the primary side of the third single-phase transformer, and the first end of the secondary side of the third single-phase transformer. Furthermore, the electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor-inductor modules and then flows through the resonant inductor. The second transformer module further includes six sets of resonant capacitor-inductor modules. Each set of resonant capacitor-inductor modules includes a resonant capacitor and a resonant inductor connected in series. The six sets of resonant capacitor-inductor modules are respectively connected in series to the first end of the primary side of the fourth single-phase transformer, the first end of the secondary side of the fourth single-phase transformer, the first end of the primary side of the fifth single-phase transformer, the first end of the secondary side of the fifth single-phase transformer, the first end of the primary side of the sixth single-phase transformer, and the first end of the secondary side of the sixth single-phase transformer. Furthermore, the electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor-inductor modules and then flows through the resonant inductor.

[0012] Optionally, the first transformer module further includes three parallel inductors, which are connected in parallel with the primary side of the first single-phase transformer, the primary side of the second single-phase transformer, and the primary side of the third single-phase transformer, respectively. The electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each group of resonant capacitor-inductor modules, then through the resonant inductor, and finally through the parallel inductors. The second transformer module also includes three parallel inductors, which are connected in parallel with the primary side of the fourth single-phase transformer, the primary side of the fifth single-phase transformer, and the primary side of the sixth single-phase transformer, respectively. The electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each group of resonant capacitor-inductor modules, then through the resonant inductor, and finally through the parallel inductors.

[0013] Optionally, the switch submodule has three components: a first switch submodule, a second switch submodule, and a third switch submodule. The first terminal of the first switch submodule is electrically connected to the second terminal of the second capacitor, and the second terminal of the first switch submodule is electrically connected to the first terminal of the third capacitor. The first terminal of the second switch submodule is connected to the first terminal of the second capacitor, and the second terminal of the second switch submodule is connected to the first terminal of the third capacitor. The first terminal of the third switch submodule is connected to the second terminal of the second capacitor, and the second terminal of the third switch submodule is connected to the second terminal of the third capacitor. The first terminal of the second switch submodule is used to connect to the positive terminal of the battery, and the second terminal of the third switch submodule is used to connect to the negative terminal of the battery.

[0014] Optionally, the circuit further includes an AC / DC converter, comprising a filter module connected in series with an AC power supply, and a fourth bridge electrically connected to the filter module, wherein the number of bridge arms of the fourth bridge is equal to the number of bridge arms of the first bridge, the second bridge, and the third bridge.

[0015] Optionally, the AC power supply has three channels: a first AC power supply, a second AC power supply, and a third AC power supply. The filtering module has three channels: a first filtering module, a second filtering module, and a third filtering module. The fourth bridge includes a first-phase and a fourth-phase switching device located on the first bridge arm, a second-phase and a fifth-phase switching device located on the second bridge arm, and a third-phase and a sixth-phase switching device located on the third bridge arm. The first ends of the three AC power supplies are connected together. The second ends of the three AC power supplies are respectively connected to the first ends of the three filtering modules. The second ends of the three filtering modules are respectively connected to an intermediate node of the first-phase and fourth-phase switching devices, an intermediate node of the second-phase and fifth-phase switching devices, and an intermediate node of the third-phase and sixth-phase switching devices.

[0016] Optionally, the switching device on each arm of the first bridge, the second bridge, and the third bridge is a MOSFET device.

[0017] According to another aspect of this application, a control method for a charging and discharging topology circuit of an electric vehicle is provided, comprising: setting the voltage of a battery as a target voltage and the current flowing through the battery as a target current; acquiring a reference current and a reference voltage; configuring the target voltage and the reference voltage to pass through a first PI controller to obtain a first PI signal; configuring the target current and the reference current to pass through a second PI controller to obtain a second PI signal; configuring the first PI signal and the second PI signal to pass through a MIN controller to obtain a PRD signal, then passing through a PRD-to-FREQ controller to obtain a FREQ signal, then passing through a FREQ-to-RAMP controller to obtain a RAMP signal, wherein the RAMP signal is used to control the opening and closing of switching devices in a first bridge, a second bridge, and a third bridge to achieve charging and discharging.

[0018] Optionally, the RAMP signal is used to control the opening and closing of switching devices in the first bridge, the second bridge, and the third bridge to achieve charging and discharging, including: the RAMP signal controls the opening and closing of switching devices in the second bridge and the third bridge to achieve discharging; the RAMP signal controls the opening and closing of switching devices in the first bridge to achieve charging.

[0019] According to another aspect of this application, a control method for a charging and discharging topology circuit of an electric vehicle is provided, comprising: setting the voltage of a battery as a first target voltage and a second target voltage, and the current flowing through the battery as a first target current and a second target current; acquiring a first reference current, a first reference voltage, a second reference current, and a second reference voltage; configuring the first target current and the first reference current to pass through a third PI controller to obtain a third PI signal, configuring the first target voltage and the first reference voltage to pass through a fourth PI controller to obtain a fourth PI signal; configuring the second target current and the second reference current to pass through a fifth PI controller to obtain a fifth PI signal, configuring the second target voltage and the second reference voltage to pass through a sixth PI controller to obtain a sixth PI signal; configuring the third PI signal and the fourth PI signal to pass through a MIN controller to obtain a PRD1 signal, and then passing through a PRD-to-FREQ controller to obtain FREQ1. The signal is then processed by a FREQ to RAMP controller to obtain the RAMP1 signal, which is used to control the opening and closing of the switching devices in the second bridge. The fifth PI signal and the sixth PI signal are configured to pass through a MIN controller to obtain a PRD2 signal, which is then processed by a PRD to FREQ controller to obtain a FREQ2 signal, which is then processed by a FREQ to RAMP controller to obtain a RAMP2 signal. The RAMP2 signal is used to control the opening and closing of the switching devices in the third bridge. The first reference current, the first reference voltage, the second reference current, and the second reference voltage are configured to pass through a seventh PI controller to obtain a reference signal. The reference signal and the FREQ1 signal are combined and then processed by a FREQ to RAMP controller to obtain the RAMP1 signal. The reference signal and the FREQ2 signal are combined and then processed by a FREQ to RAMP controller to obtain the RAMP2 signal.

[0020] By applying the technical solution of this application, the DC / DC converter includes three bridges, a first transformer module, and a second transformer module. The connection method between the bridges and the transformer modules is configured, with the first capacitor connected in parallel to each arm of the first bridge, the second capacitor connected in parallel to each arm of the second bridge, and the third capacitor connected in parallel to each arm of the third bridge. Combined with the switching function of the switching module, the voltage of the connected battery can be adjusted while achieving level conversion. This allows the DC / DC converter of this application to adapt to the circuit topology of power units with high power and power density. Furthermore, it enables the charging and discharging topology circuit of electric vehicles composed of the DC / DC converter and the AC / DC converter to adapt to the circuit topology of power units with high power and power density, thus meeting the user's high-power charging needs. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 A schematic diagram of a charging and discharging topology circuit for a first electric vehicle according to an embodiment of this application is shown;

[0023] Figure 2 A schematic diagram of a charging and discharging topology circuit for a second electric vehicle according to an embodiment of this application is shown;

[0024] Figure 3 A schematic diagram of a charging and discharging topology circuit for a third electric vehicle according to an embodiment of this application is shown;

[0025] Figure 4(a) shows a schematic diagram of the discharge mode according to an embodiment of the present application;

[0026] Figure 4(b) shows a schematic diagram of the charging mode according to an embodiment of the present application;

[0027] Figure 4(c) shows a schematic diagram of the current and voltage signal generation principle according to an embodiment of this application;

[0028] Figure 5 A schematic diagram illustrating the power averaging control principle in the discharge mode according to an embodiment of this application is shown.

[0029] The above figures include the following reference numerals:

[0030] Cdc, first capacitor; 01, DC / DC converter; 10, first bridge; 11, second bridge; 12, third bridge; Co1, second capacitor; Co2, third capacitor; 13, first transformer module; 14, second transformer module; 15, switch module; Q 11 A bridge circuit and a switching device; Q 12 One bridge circuit with two switching devices; Q 13 One bridge with three switching devices; Q 14 A bridge circuit with four switching devices; Q 15 A bridge circuit and a switching device; Q 16 One bridge circuit and one switching device; T r1 First single-phase transformer; T r2 Second single-phase transformer; T r3 The third single-phase transformer; T r4 The fourth single-phase transformer; T r5 Fifth single-phase transformer; T r6 The sixth single-phase transformer; Q 21 Two-bridge circuit with one switching device; Q 22Two-bridge, two-switch device; Q 23 Two-bridge three-switch device; Q 24 Two-bridge four-switch device; Q 25 Two-bridge five-switch device; Q 26 Two-bridge six-switch device; Q 31 A three-bridge circuit and a switching device; Q 32 Three-bridge two-switch device; Q 33 Three-bridge three-switch device; Q 34 Three-bridge four-switch device; Q 35 Three-bridge five-switch device; Q 36 C. Three-bridge six-switch device; a1 First resonant capacitor; L a1 First resonant inductor; C a2 Second resonant capacitor; L a2 Second resonant inductor; C b1 Third resonant capacitor; L b1 Third resonant inductor; C b2 Fourth resonant capacitor; L b2 Fourth resonant inductor; C c1 Fifth resonant capacitor; L c1 Fifth resonant inductor; C c2 The sixth resonant capacitor; L c2 The sixth resonant inductor; C a3 The seventh resonant capacitor; L a3 The seventh resonant inductor; C a4 Eighth resonant capacitor; L a4 Eighth resonant inductor; C b3 Ninth resonant capacitor; L b3 Ninth resonant inductor; C b4 The tenth resonant capacitor; L b4 The tenth resonant inductor; C c3 Eleventh resonant capacitor; L c3 Eleventh resonant inductor; C c4 12th resonant capacitor; L c4 12th resonant inductor; L 11 First parallel inductor; L 12 Second parallel inductor; L 13 Third parallel inductor; L 14 Fourth parallel inductor; L 15 Fifth parallel inductor; L 16S1, Sixth parallel inductor; S2, First switch submodule; S3, Third switch submodule; O2, AC / DC converter; SS1, First AC power supply; SS2, Second AC power supply; SS3, Third AC power supply; LL1, First filter module; LL2, Second filter module; LL3, Third filter module; Q 41 Four-bridge circuit with one switching device; Q 42 Four-bridge two-switch device; Q 43 Four-bridge three-switch device; Q 44 Four-bridge, four-switch device; Q 45 Four-bridge five-switch device; Q 46 Four-bridge six-switch device. Detailed Implementation

[0031] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0032] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0033] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0034] As described in the background section, the prior art lacks a circuit topology that is compatible with power units with high power and power density. In order to solve the problem of the lack of a circuit topology that is compatible with power units with high power and power density, this application proposes a charging and discharging topology circuit for electric vehicles.

[0035] This application provides a charging and discharging topology circuit for an electric vehicle, such as... Figure 1 As shown, including:

[0036] First capacitor Cdc;

[0037] DC / DC converter 01 includes: a first bridge 10, a second bridge 11, a third bridge 12, a second capacitor Co1, a third capacitor Co2, a first transformer module 13, a second transformer module 14, and a switching module 15. Each arm of the first bridge 10, the second bridge 11, and the third bridge 12 includes two switching devices connected in series. The number of arms of the first bridge 10, the second bridge 11, and the third bridge 12 is equal.

[0038] In this circuit, each arm of the first bridge 10 is connected in parallel with the first capacitor Cdc, and the first capacitor Cdc is connected to the first side of the first bridge 10. An intermediate node of two switching devices in each arm of the first bridge 10 is connected to the primary side of the first transformer module 13 and the primary side of the second transformer module 14. The secondary side of the first transformer module 13 is connected to an intermediate node of two switching devices in each arm of the second bridge 11 and an intermediate node of two switching devices in the first arm of the third bridge 12. The secondary side of the second transformer module 14 is connected to an intermediate node of two switching devices in each arm of the third bridge 12 and an intermediate node of two switching devices in the first arm of the second bridge 11. Each arm of the second bridge 11 is connected in parallel with the second capacitor Co1. The first and second sides of the third bridge 11 are connected in parallel, and the second capacitor Co2 is connected to the second side of the third bridge 12. The switch module 15 is electrically connected to the second capacitor Co1 and the third capacitor Co2 respectively. The switch module 15 is used to electrically connect to the battery. The opening or closing of the multiple switch sub-modules in the switch module 15 determines the voltage connected to the battery. The first and second sides of any bridge are opposite sides based on the multiple bridge arms. The first capacitor, the first bridge, the first transformer module, the second transformer module and the second bridge jointly determine the voltage across the second capacitor. The first capacitor, the first bridge, the first transformer module, the second transformer module and the third bridge jointly determine the voltage across the third capacitor.

[0039] The electric vehicle charging and discharging topology circuit of this application includes a DC / DC converter comprising three bridges, a first transformer module, and a second transformer module. The connection method between the bridges and transformer modules is configured, with the first capacitor connected in parallel to each arm of the first bridge, the second capacitor connected in parallel to each arm of the second bridge, and the third capacitor connected in parallel to each arm of the third bridge. Combined with the switching function of the switching module, this allows for level conversion while simultaneously adjusting the voltage connected to the battery. This enables the DC / DC converter of this application to adapt to circuit topologies of power units with high power and power density. Furthermore, it allows the charging and discharging topology circuit of the electric vehicle composed of the DC / DC converter and the AC / DC converter to adapt to circuit topologies of power units with high power and power density, thus meeting the user's high-power charging needs.

[0040] In the embodiments of this application, such as Figure 1 As shown, the first bridge 10, the second bridge 11, and the third bridge 12 each have three arms. The switching devices in the first bridge 10 include a bridge-switching device Q located on the first arm. 11 And a bridge four-switch device Q 14 A bridge with two switching devices Q located on the second bridge arm. 12 And a bridge five-switch device Q 15 The three-switch device Q of the bridge located on the third bridge arm 13 And a bridge six-switch device Q 16 The first transformer module 13 includes a first single-phase transformer T. r1 Second single-phase transformer T r2 and the third single-phase transformer T r3 The second transformer module 14 includes a fourth single-phase transformer T. r4 Fifth single-phase transformer T r5 and the sixth single-phase transformer T r6 ,

[0041] Among them, one bridge and one switching device Q 11 And a bridge four-switch device Q 14 An intermediate node is connected to the first single-phase transformer T. r1 The first end of the primary side and the fourth single-phase transformer T r4 The first end of the primary side has a bridge circuit with two switching devices Q. 12 And a bridge five-switch device Q 15 An intermediate node is connected to the first single-phase transformer T. r1 The second terminal of the primary side and the second single-phase transformer T r2 The first end of the primary side and the fourth single-phase transformer T r4 The second end of the primary side and the fifth single-phase transformer T r5The first end of the primary side, a bridge with three switching devices Q 13 And a bridge six-switch device Q 16 An intermediate node is connected to the second single-phase transformer T. r2 The second and third single-phase transformers T on the primary side r3 The first end of the primary side and the fifth single-phase transformer T r5 The second end of the primary side and the sixth single-phase transformer T r6 The first end of the primary side, the first single-phase transformer T r1 The first end of the primary side and the third single-phase transformer T r3 The second end of the primary side is connected to the fourth single-phase transformer T. r4 The first end of the primary side and the sixth single-phase transformer T r6 Connect the second end of the original side.

[0042] The first bridge circuit of this application is connected to the first single-phase transformer, the second single-phase transformer, and the third single-phase transformer. 、 The connection methods of the fourth, fifth, and sixth single-phase transformers, as well as the connection between the first terminal of the primary side of the first single-phase transformer and the second terminal of the primary side of the third single-phase transformer, and the connection between the first terminal of the primary side of the fourth single-phase transformer and the second terminal of the primary side of the sixth single-phase transformer, allow the first bridge to function simultaneously on both the first and second transformer modules, resulting in a more compact structure. This also prepares the ground for the subsequent implementation of the switching module's function.

[0043] In the embodiments of this application, such as Figure 1 As shown, the switching devices in the second bridge 11 include two bridge-one switching devices Q, each located on a first bridge arm. 21 and two-bridge four-switch device Q 24 The two-bridge switching device Q is located on the second bridge arm. 22 And two bridge five switching devices Q 25 The three-switch device Q of the two-bridge circuit located on the third bridge arm 23 And two bridge six switching devices Q 26 The first transformer module 13 includes a first single-phase transformer T. r1 Second single-phase transformer T r2 and the third single-phase transformer T r3 ,

[0044] Among them, the two-bridge switching device Q 21 and two-bridge four-switch device Q 24 An intermediate node is connected to the first single-phase transformer T. r1 The first terminal of the secondary side, a two-bridge two-switch device Q 22 And two bridge five switching devices Q 25An intermediate node is connected to the first single-phase transformer T. r1 The second terminal of the secondary side and the second single-phase transformer T r2 The first terminal of the secondary side, a two-bridge three-switch device Q 23 And two bridge six switching devices Q 26 An intermediate node is connected to the second single-phase transformer T. r2 The second and third single-phase transformer T on the secondary side r3 The first end of the secondary side, the first single-phase transformer T r1 The first end of the secondary side and the sixth single-phase transformer T r6 The second end of the secondary side is connected.

[0045] The connection method of the second bridge circuit to the first and second transformer modules, and the connection method of connecting the first end of the secondary side of the first single-phase transformer to the second end of the secondary side of the sixth single-phase transformer, enable the second bridge circuit to function simultaneously on both the first and second transformer modules, resulting in a more compact structure. Furthermore, this prepares the ground for the subsequent implementation of the switching module's function.

[0046] In the embodiments of this application, such as Figure 1 As shown, the switching devices in the third bridge 12 include a three-bridge switching device Q located on the first bridge arm. 31 and three-bridge four-switch device Q 34 The three-bridge two-switch device Q is located on the second bridge arm. 32 and three-bridge five-switch device Q 35 and the three-bridge three-switch device Q located on the third bridge arm. 33 and three-bridge six-switch device Q 36 The first transformer module 13 includes a first single-phase transformer T. r1 Second single-phase transformer T r2 and the third single-phase transformer T r3 ,

[0047] Among them, the three-bridge switching device Q 31 and three-bridge four-switch device Q 34 An intermediate node is connected to the third single-phase transformer T. r3 The second end of the secondary side and the fourth single-phase transformer T r4 The first terminal of the secondary side, the three-bridge two-switch device Q 32 and three-bridge five-switch device Q 35 An intermediate node is connected to the fourth single-phase transformer T. r4 The second end of the secondary side and the fifth single-phase transformer T r5 The first terminal of the secondary side, the three-bridge three-switch device Q 33 and three-bridge six-switch device Q 36An intermediate node is connected to the fifth single-phase transformer T. r5 The second end of the secondary side and the sixth single-phase transformer T r6 The first end of the secondary side.

[0048] The connection method of the third bridge in this application with the first and second transformer modules allows the third bridge to function simultaneously on both modules, resulting in a more compact structure. Furthermore, it prepares the ground for the subsequent implementation of the switching module's functionality.

[0049] In the embodiments of this application, such as Figure 1 As shown, the first transformer module 13 also includes six sets of resonant capacitor and inductor modules. Each set of resonant capacitor and inductor modules includes a resonant capacitor and a resonant inductor connected in series. The six sets of resonant capacitor and inductor modules are respectively connected in series to the first single-phase transformer T. r1 The first end of the primary side, the first single-phase transformer T r1 The first end of the secondary side, the second single-phase transformer T r2 The first end of the primary side, the second single-phase transformer T r2 The first end of the secondary side, the third single-phase transformer T r3 The first end of the primary side, the third single-phase transformer T r3 At the first end of the secondary side, the electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor-inductor modules and then through the resonant inductor; that is, the inductor in each set of resonant capacitor-inductor modules is close to the primary or secondary side of the single-phase transformer, and the capacitor in each set of resonant capacitor-inductor modules is far away from the primary or secondary side of the single-phase transformer.

[0050] The first transformer module 13 includes six sets of resonant capacitor and inductor modules, namely: the first resonant capacitor C a1 and the first resonant inductor L a1 The resonant capacitor-inductor module consists of a second resonant capacitor C. a2 Second resonant inductor L a2 The resonant capacitor-inductor module consists of a third resonant capacitor C. b1 and the third resonant inductor L b1 The resonant capacitor-inductor module consists of the fourth resonant capacitor C. b2 and the fourth resonant inductor L b2 The resonant capacitor-inductor module consists of the fifth resonant capacitor C. c1 and the fifth resonant inductor L c1 The resonant capacitor-inductor module consists of the sixth resonant capacitor C. c2 and the sixth resonant inductor L c2 The resonant capacitor and inductor module is composed of these components.

[0051] The second transformer module 14 also includes six sets of resonant capacitor-inductor modules. Each set of resonant capacitor-inductor modules includes a resonant capacitor and a resonant inductor connected in series. The six sets of resonant capacitor-inductor modules are respectively connected in series with the fourth single-phase transformer T. r4 The first end of the primary side, the fourth single-phase transformer T r4 The first end of the secondary side, the fifth single-phase transformer T r5 The first end of the primary side, the fifth single-phase transformer T r5 The first end of the secondary side, the sixth single-phase transformer T r6 The first end of the primary side, the sixth single-phase transformer T r6 The first end of the secondary side, wherein the electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor-inductor modules and then through the resonant inductor. That is, the inductor in each set of resonant capacitor-inductor modules is close to the primary or secondary side of the single-phase transformer, and the capacitor in each set of resonant capacitor-inductor modules is far away from the primary or secondary side of the single-phase transformer.

[0052] The second transformer module includes six sets of resonant capacitor and inductor modules, namely: the seventh resonant capacitor C a3 and the seventh resonant inductor L a3 The resonant capacitor-inductor module consists of the eighth resonant capacitor C. a4 and the eighth resonant inductor L a4 The resonant capacitor-inductor module consists of the ninth resonant capacitor C. b3 and the ninth resonant inductor L b3 The resonant capacitor-inductor module consists of the tenth resonant capacitor C. b4 and the tenth resonant inductor L b4 The resonant capacitor-inductor module consists of the eleventh resonant capacitor C. c3 And the eleventh resonant inductor L c3 The resonant capacitor-inductor module consists of the twelfth resonant capacitor C. c4 and the twelfth resonant inductor L c4 A resonant capacitor and inductor module.

[0053] In the electric vehicle charging and discharging topology circuit of this application, the resonant capacitor and inductor module, together with a single-phase transformer, form a resonant converter. Traditional high-power resonant converters typically increase the current level and thus the converter's power through parallel connections. However, the input impedance of a resonant converter is significantly affected by inconsistent device parameters. When the parameters of the resonant cavity devices are inconsistent, uneven current distribution between converters can easily occur, potentially leading to overcurrent or overheating issues. The connection method used in the converter of this invention provides better current sharing characteristics even when converter parameters are inconsistent.

[0054] In the embodiments of this application, such as Figure 1As shown, the first transformer module 13 also includes three parallel inductors, which are respectively connected to the first single-phase transformer T. r1 Primary side parallel, second single-phase transformer T r2 Primary-side parallel, third single-phase transformer T r3 The primary side of the transformer is connected in parallel, and the electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each group of the resonant capacitor-inductor modules, then through the resonant inductor, and then through the parallel inductor. That is, any parallel inductor is closer to the primary or secondary side of the single-phase transformer than the inductor in the resonant capacitor-inductor module.

[0055] Among them, the three parallel inductors of the first transformer module are the first parallel inductor L 11 Second parallel inductor L 12 Third parallel inductor L 13 ;

[0056] The second transformer module 14 also includes three parallel inductors, which are respectively connected to the fourth single-phase transformer T. r4 Primary parallel connection, fifth single-phase transformer T r5 Primary-side parallel, sixth single-phase transformer T r6 The primary side is connected in parallel, and any parallel inductor is closer to the primary or secondary side of the single-phase transformer than the inductor in the resonant capacitor-inductor module.

[0057] Among them, the three parallel inductors of the second transformer module are respectively the fourth parallel inductor L 14 Fifth parallel inductor L 15 and the sixth parallel inductor L 16 .

[0058] In this embodiment, the combination of parallel inductor, resonant capacitor-inductor module, and single-phase transformer ensures the stability of the resonant converter's operating performance.

[0059] In the embodiments of this application, such as Figure 2 As shown, there are three switch submodules: a first switch submodule S1, a second switch submodule S2, and a third switch submodule S3. The first terminal of the first switch submodule S1 is electrically connected to the second terminal of the second capacitor Co1, and the second terminal of the first switch submodule S1 is electrically connected to the first terminal of the third capacitor Co2. The first terminal of the second switch submodule S2 is electrically connected to the first terminal of the second capacitor Co1, and the second terminal of the second switch submodule S2 is electrically connected to the first terminal of the third capacitor Co2. The first terminal of the third switch submodule S3 is electrically connected to the second terminal of the second capacitor Co1, and the second terminal of the third switch submodule S3 is electrically connected to the second terminal of the third capacitor Co2. The first terminal of the second switch submodule S2 is used to connect to the positive terminal of the battery, and the second terminal of the third switch submodule S3 is used to connect to the negative terminal of the battery.

[0060] See Figure 2 By controlling the opening and closing of the first switch submodule S1, the second switch submodule S2, and the third switch submodule S3, multiple voltages can be connected to the battery.

[0061] In this embodiment of the application, the circuit further includes: Figure 1 and Figure 3 As shown, the AC / DC converter 02 includes: an AC power supply, a filter module connected in series with the AC power supply, and a fourth bridge electrically connected to the filter module. The number of bridge arms of the fourth bridge is equal to the number of bridge arms of the first bridge 10, the second bridge 11, and the third bridge 12.

[0062] In this embodiment, there are three AC power supplies: a first AC power supply SS1, a second AC power supply SS2, and a third AC power supply SS3. There are also three filtering modules: a first filtering module LL1, a second filtering module LL2, and a third filtering module LL3. The fourth bridge includes a four-bridge circuit and a switching device Q, each located on a separate first bridge arm. 41 and four-bridge four-switch device Q 44 The four-bridge two-switch device Q is located on the second bridge arm. 42 and four bridge five switching devices Q 45 The four-bridge three-switch device Q is located on the third bridge arm. 43 and four bridge six switching devices Q 46 The first terminals of the three AC power supplies are connected, and the second terminals of the three AC power supplies are respectively connected to the first terminals of the three filter modules. The second terminals of the three filter modules are respectively connected to the four-bridge switching device Q. 41 and four-bridge four-switch device Q 44 One intermediate node, four-bridge two-switch device Q 42 and four bridge five switching devices Q 45 One intermediate node, four bridges, three switching devices Q 42 and four bridge six switching devices Q 46 An intermediate node.

[0063] The electric vehicle charging and discharging topology circuit of this application includes an AC / DC converter and a DC / DC converter. The AC / DC converter includes a bridge circuit, and the DC / DC converter includes three bridge circuits, a first transformer module, and a second transformer module. This combination of AC / DC converter and DC / DC converter can realize bidirectional charging, meeting the development needs of electric vehicles.

[0064] In this embodiment, the switching device on each arm of the first bridge 10, the second bridge 11, and the third bridge 12 is a MOSFET device.

[0065] Alternatively, if the AC / DC section uses silicon-based MOSFET devices, a three-level converter, such as an NPC or a T-type three-level converter, can be used.

[0066] Optionally, if the DC / DC section uses silicon-based MOSFET devices, then the primary side three-phase half-bridge, i.e., the first bridge Q, is... 11 ~Q 16 The secondary side three-phase half-bridge, i.e., the second bridge Q 21 ~Q 26 The third bridge Q 31 ~Q 36 Three-phase half-bridges of the three-level type can be used in both cases.

[0067] The charging and discharging principle of the electric vehicle charging and discharging topology circuit of this application will be described below. The control method of the AC / DC part is the same as that of the traditional AC / DC controller. The main control objectives are to stabilize the voltage of the control capacitor Cdc and to ensure that the reactive power output of the AC port is 0.

[0068] This application also provides a control method for the charging and discharging topology circuit of an electric vehicle, including:

[0069] Set the battery voltage as the target voltage and the current flowing through the battery as the target current;

[0070] Obtain the reference current and reference voltage;

[0071] The target voltage and the reference voltage are configured to pass through a first PI controller to obtain a first PI signal, and the target current and the reference current are configured to pass through a second PI controller to obtain a second PI signal;

[0072] The first PI signal and the second PI signal are configured to pass through the MIN controller to obtain the PRD signal, then through the PRD to FREQ controller to obtain the FREQ signal, and then through the FREQ to RAMP controller to obtain the RAMP signal. The RAMP signal is used to control the opening and closing of the switching devices in the first bridge, the second bridge and the third bridge to realize charging and discharging.

[0073] Specifically, the RAMP signal is used to control the opening and closing of the switching devices in the first bridge, second bridge, and third bridge to achieve charging and discharging, including:

[0074] The RAMP signal discharges by controlling the opening and closing of the switching devices in the second and third bridges.

[0075] The RAMP signal controls the opening and closing of the switching devices in the first bridge to achieve charging.

[0076] The control of the DC / DC converter is divided into charging mode and discharging mode. The charging mode is mainly controlled by the switching transistor Q. 11 ~Q 16 Achieve power control, Q 21 ~Q 26 Q 31 ~Q 36 The traditional synchronous rectification control method can be used. In charging mode, Q is shown in Figure 4(b). 11 ~Q 16 The control method involves two loops: a voltage loop and a current loop. A dual-loop competition mechanism determines whether the voltage loop or the current loop is dominant, outputting a periodic signal PRD. The periodic signal PRD is converted into a frequency signal FREQ by a relevant conversion module. The frequency signal is then converted into a sawtooth wave signal RAMP by another relevant conversion module. RAMP is a signal with a period equal to FREQ and an amplitude ranging from 0 to 1. The magnitude of RAMP is then used to determine Q. 11 Q 12 Q 13 The pulse signal, where t db This is the dead time. The pulse signal Q... 14 Q 15 Q 16 Then by Q 11 Q 12 Q 13 The signal is obtained by performing a logical NOT operation and applying a delay to enable conduction.

[0077] Specifically, as shown in Figures 4(a), 4(b), and 4(c); Q in Figures 4(a), 4(b), and 4(c) 21 Q 31 Q 22 Q 32 Q 35 Q 25 etc. represent Figures 1 to 3 The switching transistor Q in 21 Switching transistor Q 31 Switching transistor Q 22 Switching transistor Q 32 Switching transistor Q 35 Switching transistor Q 25 The gate drive signal will not be described in detail here.

[0078] The discharge mode is shown in Figure 4(a). The target voltage Vo and the reference voltage V_ref are processed by a first PI controller to obtain a first PI signal. The target current Io and the reference current I_ref are processed by a second PI controller to obtain a second PI signal. Specifically, IF RAMP < 0.5-t db Q 21=Q 31 =1, else Q 21 =Q 31 =0, Q 21 and Q 31 After negation and delay, Q is obtained. 34 and Q 24 ;IF 0.3333≤RAMP<0.8333-t db Q 22 =Q 32 =1, else Q 22 =Q 32 =0, Q 22 and Q 32 After negation and delay, Q is obtained. 35 and Q 25 ;IF 0.6666≤RAMP or RAMP<0.1666-t db Q 23 =Q 33 =1, else Q 23 =Q 33 =0, Q 23 and Q 33 After negation and delay, Q is obtained. 36 and Q 26。

[0079] The discharge mode is shown in Figure 4(b). The target voltage Vo and the reference voltage V_ref are processed by a first PI controller to obtain a first PI signal. The target current Io and the reference current I_ref are processed by a second PI controller to obtain a second PI signal. Specifically, IF RAMP < 0.5-t db Q 11 =1, else Q 11 =0, Q 11 After negation and delay, Q is obtained. 14 ;IF 0.3333≤RAMP<0.8333-t db Q 12 =1, else Q 12 =0, Q 12 After negation and delay, Q is obtained. 15 ;IF 0.6666≤RAMP or RAMP<0.1666-t db Q 13 =1, else Q 13 =0, Q 13 After negation and delay, Q is obtained. 16 ;

[0080] Figure 4(c) shows the specific schematic diagram for generating the target voltage Vo and the target current Io.

[0081] This application also provides a control method for the charging and discharging topology circuit of an electric vehicle, including:

[0082] The battery voltage is set as a first target voltage and a second target voltage, and the current flowing through the battery is set as a first target current and a second target current.

[0083] Obtain the first reference current, the first reference voltage, the second reference current, and the second reference voltage;

[0084] The first target current and the first reference current are configured to pass through the third PI controller to obtain the third PI signal, and the first target voltage and the first reference voltage are configured to pass through the fourth PI controller to obtain the fourth PI signal.

[0085] The second target current and the second reference current are configured and passed through the fifth PI controller to obtain the fifth PI signal; the second target voltage and the second reference voltage are configured and passed through the sixth PI controller to obtain the sixth PI signal.

[0086] The third PI signal and the fourth PI signal are configured to pass through the MIN controller to obtain the PRD1 signal, then through the PRD to FREQ controller to obtain the FREQ1 signal, and then through the FREQ to RAMP controller to obtain the RAMP1 signal. The RAMP1 signal is used to control the opening and closing of the switching devices in the second bridge.

[0087] The fifth PI signal and the sixth PI signal are configured to pass through the MIN controller to obtain the PRD2 signal, then through the PRD to FREQ controller to obtain the FREQ2 signal, and then through the FREQ to RAMP controller to obtain the RAMP2 signal. The RAMP2 signal is used to control the opening and closing of the switching devices in the third bridge.

[0088] The first reference current, the first reference voltage, the second reference current, and the second reference voltage are configured and passed through the seventh PI controller to obtain a reference signal. The reference signal and the FREQ1 signal are combined and then passed through the FREQ to RAMP controller to obtain the RAMP1 signal. The reference signal and the FREQ2 signal are combined and then passed through the FREQ to RAMP controller to obtain the RAMP2 signal.

[0089] Specifically, such as Figure 5As shown, the first target current Io1 and the first reference current I_ref1 pass through the third PI controller to obtain the third PI signal; the first target voltage Vco1 and the first reference voltage V_ref1 pass through the fourth PI controller to obtain the fourth PI signal; the second target current Io2 and the second reference current I_ref2 pass through the fifth PI controller to obtain the fifth PI signal; and the second target voltage Vco2 and the second reference voltage V_ref2 are configured to pass through the sixth PI controller to obtain the sixth PI signal; specifically, IF RAMP1 < 0.5-t db Q 21 =1, else Q 21 =0;IF 0.3333≤RAMP1<0.8333-t db Q 22 =1, else Q 22 =0;IF 0.6666≤RAMP1 or RAMP1<0.1666-t db Q 23 =1, else Q 23 =0;Q 21 After negation and delay, Q is obtained. 24 Q 22 After negation and delay, Q is obtained. 25 Q 23 After negation and delay, Q is obtained. 26 ; Specifically, IF RAMP2<0.5-tdb, Q31=1, else Q31=0; IF 0.3333≤RAMP2<0.8333-t db Q 32 =1, else Q 32 =0;IF 0.6666≤RAMP2 or RAMP2<0.1666-t db Q 33 =1, else Q 33 =0;Q 31 After negation and delay, Q is obtained. 34 Q 32 After negation and delay, Q is obtained. 35 Q 33 After negation and delay, Q is obtained. 36 .

[0090] Figures 4(a), 4(b), and 4(c) and Figure 5 Q in 21 Q 31 Q 22 Q 32 Q 35 Q 25etc. represent Figures 1 to 3 The switching transistor Q in 21 Switching transistor Q 31 Switching transistor Q 22 Switching transistor Q 32 Switching transistor Q 35 Switching transistor Q 25 The gate drive signal will not be described in detail here.

[0091] During discharge, the switching transistor Q 21 ~Q 26 With Q 31 ~Q 36 The control method is similar. It is worth noting that, due to the good current sharing characteristics of the circuit topology of this invention, Q can achieve high current sharing even with small errors in the converter component parameters. 21 ~Q 26 With Q 31 ~Q 36 The control signals can be completely identical. Alternatively, one can use... Figure 5 The control method in this paper involves controlling the two sets of three-phase CLLC converters on the secondary side separately, and adding power averaging control. That is, by calculating the power difference between the two sets of three-phase CLLC converters, the signal Δf is obtained through the seventh PI controller and added to the FREQ1 and FREQ2 signals respectively to achieve power averaging control.

[0092] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0093] The electric vehicle charging and discharging topology circuit of this application, compared to traditional circuits with two DC / DC resonators connected in series on the primary side and in series or parallel on the secondary side, shares a common primary-side switch, resulting in a more compact structure. Traditional high-power resonant converters increase current levels and thus converter power through parallel connections. However, the input impedance of resonant converters is significantly affected by inconsistent device parameters. When the parameters of the resonant cavity devices are inconsistent, uneven current distribution between converters can easily occur, potentially leading to overcurrent or overheating problems. The converter in this invention, using the connection method of this application, exhibits better current sharing characteristics even when converter parameters are inconsistent.

[0094] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A charging and discharging topology circuit for an electric vehicle, characterized in that, include: First capacitor; A DC / DC converter includes: a first bridge, a second bridge, a third bridge, a second capacitor, a third capacitor, a first transformer module, a second transformer module, and a switching module. Each arm of the first bridge, the second bridge, and the third bridge includes two switching devices connected in series. The number of arms of the first bridge, the second bridge, and the third bridge is equal. The first, second, and third bridges each have three arms. Each arm of the first bridge is connected in parallel with the first capacitor, and the first capacitor is connected to the first side of the first bridge. A midpoint of two switching devices in each arm of the first bridge is connected to the primary side of the first transformer module and the primary side of the second transformer module. The secondary side of the first transformer module is connected to a midpoint of two switching devices in each arm of the second bridge and a midpoint of two switching devices in the first arm of the third bridge. The secondary side of the second transformer module is connected to a midpoint of two switching devices in each arm of the third bridge and a midpoint of two switching devices in the first arm of the second bridge. Each arm of the second bridge is connected in parallel with the second capacitor. The second capacitor is connected in parallel with the second bridge arm, and each arm of the third bridge arm is connected in parallel with the third capacitor, and the third capacitor is connected to the second side of the third bridge arm. The switching module is electrically connected to the second capacitor and the third capacitor respectively. The switching module is used to electrically connect to the battery. The opening or closing of multiple switching sub-modules in the switching module determines the voltage connected to the battery. The first side and the second side of any bridge arm are opposite sides based on multiple bridge arms. The first capacitor, the first bridge arm, the first transformer module, the second transformer module, and the second bridge arm jointly determine the voltage across the second capacitor. The first capacitor, the first bridge arm, the first transformer module, the second transformer module, and the third bridge arm jointly determine the voltage across the third capacitor.

2. The charging and discharging topology circuit for an electric vehicle according to claim 1, characterized in that, The switching devices in the first bridge include a bridge-one switching device and a bridge-four switching device located on the first bridge arm, a bridge-two switching device and a bridge-five switching device located on the second bridge arm, and a bridge-three switching device and a bridge-six switching device located on the third bridge arm. The first transformer module includes a first single-phase transformer, a second single-phase transformer and a third single-phase transformer. The second transformer module includes a fourth single-phase transformer, a fifth single-phase transformer and a sixth single-phase transformer. In this circuit, an intermediate node of one switch device of the bridge circuit and an intermediate node of four switch devices of the bridge circuit are connected to the first end of the primary side of the first single-phase transformer and the first end of the primary side of the fourth single-phase transformer. An intermediate node of two switch devices of the bridge circuit and an intermediate node of five switch devices of the bridge circuit are connected to the second end of the primary side of the first single-phase transformer, the first end of the primary side of the second single-phase transformer, the second end of the primary side of the fourth single-phase transformer, and the first end of the primary side of the fifth single-phase transformer. An intermediate node of three switch devices of the bridge circuit and an intermediate node of six switch devices of the bridge circuit are connected to the second end of the primary side of the second single-phase transformer, the first end of the primary side of the third single-phase transformer, the second end of the primary side of the fifth single-phase transformer, and the first end of the primary side of the sixth single-phase transformer. The first end of the primary side of the first single-phase transformer is connected to the second end of the primary side of the third single-phase transformer, and the first end of the primary side of the fourth single-phase transformer is connected to the second end of the primary side of the sixth single-phase transformer.

3. The charging and discharging topology circuit for an electric vehicle according to claim 2, characterized in that, The switching devices in the second bridge include a bridge-one switching device and a bridge-four switching device located on the first arm, a bridge-two switching device and a bridge-five switching device located on the second arm, and a bridge-three switching device and a bridge-six switching device located on the third arm. The first transformer module includes a first single-phase transformer, a second single-phase transformer, and a third single-phase transformer. In this configuration, an intermediate node of one switch device of the two-bridge circuit and an intermediate node of four switch devices of the two-bridge circuit are connected to the first end of the secondary side of the first single-phase transformer; an intermediate node of two switch devices of the two-bridge circuit and an intermediate node of five switch devices of the two-bridge circuit are connected to the second end of the secondary side of the first single-phase transformer and the first end of the secondary side of the second single-phase transformer; an intermediate node of three switch devices of the two-bridge circuit and an intermediate node of six switch devices of the two-bridge circuit are connected to the second end of the secondary side of the second single-phase transformer and the first end of the secondary side of the third single-phase transformer; and the first end of the secondary side of the first single-phase transformer is connected to the second end of the secondary side of the sixth single-phase transformer.

4. The charging and discharging topology circuit for an electric vehicle according to claim 2, characterized in that, The switching devices in the third bridge include a bridge-one switching device and a bridge-four switching device located on the first bridge arm, a bridge-two switching device and a bridge-five switching device located on the second bridge arm, and a bridge-three switching device and a bridge-six switching device located on the third bridge arm. The first transformer module includes a first single-phase transformer, a second single-phase transformer, and a third single-phase transformer. In this configuration, an intermediate node of the three-bridge switching device 1 and the three-bridge switching device 4 is connected to the second end of the secondary side of the third single-phase transformer and the first end of the secondary side of the fourth single-phase transformer; an intermediate node of the three-bridge switching device 2 and the three-bridge switching device 5 is connected to the second end of the secondary side of the fourth single-phase transformer and the first end of the secondary side of the fifth single-phase transformer; and an intermediate node of the three-bridge switching device 3 and the three-bridge switching device 6 is connected to the second end of the secondary side of the fifth single-phase transformer and the first end of the secondary side of the sixth single-phase transformer.

5. The charging and discharging topology circuit for an electric vehicle according to claim 2, characterized in that, The first transformer module also includes six sets of resonant capacitor and inductor modules. Each set of resonant capacitor and inductor modules includes a resonant capacitor and a resonant inductor connected in series. The six sets of resonant capacitor and inductor modules are respectively connected in series at the first end of the primary side of the first single-phase transformer, the first end of the secondary side of the first single-phase transformer, the first end of the primary side of the second single-phase transformer, the first end of the secondary side of the second single-phase transformer, the first end of the primary side of the third single-phase transformer, and the first end of the secondary side of the third single-phase transformer. Furthermore, the electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor and inductor modules and then flows through the resonant inductor. The second transformer module also includes six sets of resonant capacitor and inductor modules. Each set of resonant capacitor and inductor modules includes a resonant capacitor and a resonant inductor connected in series. The six sets of resonant capacitor and inductor modules are respectively connected in series to the first end of the primary side of the fourth single-phase transformer, the first end of the secondary side of the fourth single-phase transformer, the first end of the primary side of the fifth single-phase transformer, the first end of the secondary side of the fifth single-phase transformer, the first end of the primary side of the sixth single-phase transformer, and the first end of the secondary side of the sixth single-phase transformer. Furthermore, the electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor and inductor modules and then flows through the resonant inductor.

6. The charging and discharging topology circuit for an electric vehicle according to claim 5, characterized in that, The first transformer module also includes three parallel inductors. The three parallel inductors are connected in parallel with the primary side of the first single-phase transformer, the primary side of the second single-phase transformer, and the primary side of the third single-phase transformer, respectively. The electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor-inductor modules, then through the resonant inductor, and then through the parallel inductors. The second transformer module also includes three parallel inductors. The three parallel inductors are connected in parallel with the primary side of the fourth single-phase transformer, the primary side of the fifth single-phase transformer, and the primary side of the sixth single-phase transformer, respectively. The electrical signal flowing into the primary or secondary side of the single-phase transformer first flows through the resonant capacitor in each set of resonant capacitor-inductor modules, then through the resonant inductor, and finally through the parallel inductors.

7. The charging and discharging topology circuit for an electric vehicle according to claim 1, characterized in that, The switch submodule comprises three components: a first switch submodule, a second switch submodule, and a third switch submodule. The first terminal of the first switch submodule is electrically connected to the second terminal of the second capacitor, and the second terminal of the first switch submodule is electrically connected to the first terminal of the third capacitor. The first terminal of the second switch submodule is connected to the first terminal of the second capacitor, and the second terminal of the second switch submodule is connected to the first terminal of the third capacitor. The first terminal of the third switch submodule is connected to the second terminal of the second capacitor, and the second terminal of the third switch submodule is connected to the second terminal of the third capacitor. The first terminal of the second switch submodule is used to connect to the positive terminal of the battery, and the second terminal of the third switch submodule is used to connect to the negative terminal of the battery.

8. The charging and discharging topology circuit for an electric vehicle according to claim 1, characterized in that, The circuit also includes: An AC / DC converter includes: a filter module for series connection with an AC power supply, and a fourth bridge electrically connected to the filter module, wherein the number of bridge arms of the fourth bridge is equal to the number of bridge arms of the first bridge, the second bridge, and the third bridge.

9. The charging and discharging topology circuit for an electric vehicle according to claim 8, characterized in that, The AC power supply has three channels: a first AC power supply, a second AC power supply, and a third AC power supply. The filtering modules have three components: a first filtering module, a second filtering module, and a third filtering module. The fourth bridge includes a first-phase and a fourth-phase switching device on the first bridge arm, a second-phase and a fifth-phase switching device on the second bridge arm, and a third-phase and a sixth-phase switching device on the third bridge arm. The first terminals of the three AC power supplies are connected together. The second terminals of the three AC power supplies are connected to the first terminals of the three filtering modules. The second terminals of the three filtering modules are connected to intermediate nodes of the first-phase and fourth-phase switching devices, the second-phase and fifth-phase switching devices, and the third-phase and sixth-phase switching devices, respectively.

10. The charging and discharging topology circuit for an electric vehicle according to any one of claims 1 to 9, characterized in that, The switching device on each arm of the first bridge, the second bridge, and the third bridge is a MOSFET device.

11. A control method for the charging and discharging topology circuit of an electric vehicle according to any one of claims 1 to 10, characterized in that, include: Set the battery voltage as the target voltage and the current flowing through the battery as the target current; Obtain the reference current and reference voltage; The target voltage and the reference voltage are configured to pass through a first PI controller to obtain a first PI signal, and the target current and the reference current are configured to pass through a second PI controller to obtain a second PI signal; The first PI signal and the second PI signal are configured to pass through the MIN controller to obtain the PRD signal, then through the PRD to FREQ controller to obtain the FREQ signal, and then through the FREQ to RAMP controller to obtain the RAMP signal. The RAMP signal is used to control the opening and closing of the switching devices in the first bridge, the second bridge and the third bridge to realize charging and discharging.

12. The control method for an electric vehicle according to claim 11, characterized in that, The RAMP signal is used to control the opening and closing of the switching devices in the first, second, and third bridges to achieve charging and discharging, including: The RAMP signal discharges by controlling the opening and closing of the switching devices in the second and third bridges. The RAMP signal controls the opening and closing of the switching devices in the first bridge to achieve charging.

13. A control method for the charging and discharging topology circuit of an electric vehicle according to any one of claims 1 to 10, characterized in that, include: The battery voltage is set as a first target voltage and a second target voltage, and the current flowing through the battery is set as a first target current and a second target current. Obtain the first reference current, the first reference voltage, the second reference current, and the second reference voltage; The first target current and the first reference current are configured to pass through the third PI controller to obtain the third PI signal, and the first target voltage and the first reference voltage are configured to pass through the fourth PI controller to obtain the fourth PI signal. The second target current and the second reference current are configured and passed through the fifth PI controller to obtain the fifth PI signal; the second target voltage and the second reference voltage are configured and passed through the sixth PI controller to obtain the sixth PI signal. The third PI signal and the fourth PI signal are configured to pass through the MIN controller to obtain the PRD1 signal, then through the PRD to FREQ controller to obtain the FREQ1 signal, and then through the FREQ to RAMP controller to obtain the RAMP1 signal. The RAMP1 signal is used to control the opening and closing of the switching devices in the second bridge. The fifth PI signal and the sixth PI signal are configured to pass through the MIN controller to obtain the PRD2 signal, then through the PRD to FREQ controller to obtain the FREQ2 signal, and then through the FREQ to RAMP controller to obtain the RAMP2 signal. The RAMP2 signal is used to control the opening and closing of the switching devices in the third bridge. The first reference current, the first reference voltage, the second reference current, and the second reference voltage are configured and passed through the seventh PI controller to obtain a reference signal. The reference signal and the FREQ1 signal are combined and then passed through the FREQ to RAMP controller to obtain the RAMP1 signal. The reference signal and the FREQ2 signal are combined and then passed through the FREQ to RAMP controller to obtain the RAMP2 signal.

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