A high-voltage charging circuit for an electric vehicle

Abstract

The utility model relates to a kind of electric vehicle high-voltage charging circuit, including battery pack module, energy conversion module, charging switching module, voltage detection port and charging pile module;Battery pack module includes battery, first switch and second switch;Energy conversion module includes three-phase motor and three-phase full-bridge inverter;The three bridge arms of three-phase full-bridge inverter connect the three-phase winding of three-phase motor, two bus ends connect first switch and second switch;Charging switching module includes the fourth switch and the fifth switch respectively connected with two phases of three-phase winding.Compared with prior art, the utility model has the advantages that controlling the closure of the fourth switch and the fifth switch can make the charging pile module step-up charge the battery pack module or directly charge the battery pack module, meet two charging modes;The health status of charging switch can be judged before charging and when vehicle is normally driven by detecting through voltage detection port, to ensure the safety of charging circuit and the like.

Description

Technical Field

[0001] This utility model relates to electric vehicle charging technology, and in particular to a high-voltage charging circuit for electric vehicles. Background Technology

[0002] Electric vehicle charging technologies are diverse. AC charging is divided into slow charging stations and portable charging guns; the former has lower power and takes longer but has less impact on the power grid. DC fast charging has higher power and can charge the battery to 50%-80% in about half an hour. In addition, new technologies such as wireless charging and smart charging are also constantly developing.

[0003] A search revealed that application publication number CN118107438A discloses an energy conversion device and a vehicle, specifically disclosing that: when the battery voltage is lower than the charging pile voltage, the charging pile 40 directly charges the high-voltage battery by closing switches S1, S4, S5, and S6; when the battery voltage is higher than the charging pile voltage, S1, S7, and S9 are first closed, and the inverter 20 switch is controlled to operate in BUCK mode to charge the charging port capacitor C; secondly, after the voltage reaches the charging pile's operating range, switch S4 is closed, controlling the inverter switch to enter boost mode to charge the high-voltage battery pack. However, this prior art cannot charge if the boost relay S9 is damaged.

[0004] Application publication number CN114513147A discloses a voltage conversion system, control method, and electric vehicle. Specifically, it discloses that by controlling the on / off state of the charging input power supply and each phase winding, three identical voltage conversion units are formed, and the three voltage conversion units are controlled to work in turn in sequence and at equal periods, so that the effective time for each phase winding to participate in voltage conversion is the same. However, this prior art cannot detect the health status of the charging switch.

[0005] In summary, the technical problem that needs to be solved is how to design a high-voltage charging circuit for electric vehicles that can charge even when the boost relay is damaged and can detect the status of the charging switch. Utility Model Content

[0006] The purpose of this invention is to overcome the shortcomings of poor charging reliability in the existing technology and to provide a high-voltage charging circuit for electric vehicles.

[0007] The objective of this utility model can be achieved through the following technical solutions.

[0008] According to one aspect of the present invention, a high-voltage charging circuit for an electric vehicle is provided, comprising a battery pack module, an energy conversion module, a charging switching module, and a charging pile module; a voltage detection port is installed between the charging switching module and the charging pile module.

[0009] The battery pack module includes a battery, a first switch, and a second switch; the first switch and the second switch are respectively connected to both ends of the battery.

[0010] The energy conversion module includes a three-phase motor and a three-phase full-bridge inverter. The three-phase full-bridge inverter includes six switching devices, which form three bridge arms. Each bridge arm includes two switching devices. The three-phase windings of the three-phase motor are respectively connected to the midpoints of the three bridge arms. The first bus terminal of the three-phase full-bridge inverter is connected to the first switch, and the second bus terminal is connected to the second switch.

[0011] The charging switching module includes a fourth switch, a fifth switch, a first capacitor, and a first inductor; one end of the fourth switch and the fifth switch are respectively connected to two phases of the three-phase winding, and the other end is connected to one end of the first inductor. The other end of the first inductor is connected to one end of the first capacitor and one end of the charging pile module; the other end of the first capacitor is connected to the other end of the charging pile module and the second bus terminal.

[0012] As a preferred technical solution, the bridge arm includes a first bridge arm, a second bridge arm, and a third bridge arm. The first bridge arm includes a first switching device and a second switching device. The second bridge arm includes a third switching device and a fourth switching device. The third bridge arm includes a fifth switching device and a sixth switching device. The three-phase winding includes phase A, phase B, and phase C. The inductance of phase A is connected to the midpoint of the first bridge arm. The inductance of phase B is connected to the midpoint of the second bridge arm. The inductance of phase C is connected to the midpoint of the third bridge arm.

[0013] The fourth switch is connected between the inductance of phase A and the midpoint of the first bridge arm, and the fifth switch is connected between the inductance of phase C and the midpoint of the third bridge arm.

[0014] As a preferred technical solution, when the circuit is in the first connection state, the first and second switches are closed, and one of the fourth and fifth switches is closed; when the fourth switch is closed, the first switching device is intermittently switched on and off, and when the fifth switch is closed, the fifth switching device is intermittently switched on and off; the voltage detection port is connected to a detection device.

[0015] As a preferred technical solution, when the circuit is in the second connection state, the first switch, the second switch, the fourth switch and the fifth switch are closed, and the first switch device (211), the second switch device (212), the third switch device (213), the fourth switch device (214), the fifth switch device (215) and the sixth switch device (216) are open.

[0016] As a preferred technical solution, when the circuit is in the third connection state, the first switch, the second switch, the fourth switch and the fifth switch are closed; the second switch device, the third switch device, the fourth switch device and the sixth switch device are open, and the first switch device and the fifth switch device are closed at intervals.

[0017] As a preferred technical solution, when the circuit is in the fourth connection state, the first switch, the second switch, the fourth switch, and the fifth switch are closed; the first switch device, the second switch device, the fifth switch device, and the sixth switch device are open; and one of the third switch device and the fourth switch device is closed.

[0018] As a preferred technical solution, when the circuit is in the fifth connection state, the first switch and the second switch are closed, the fourth switch is open, the fifth switch is closed, the first switch and the second switch are closed alternately, the third switch and the fourth switch are closed alternately, and the fifth switch and the sixth switch are open.

[0019] As a preferred technical solution, when the circuit is in the sixth connection state, the first and second switches are closed, the fourth switch is closed, the fifth switch is open, the third and fourth switches are closed alternately, the fifth and sixth switches are closed alternately, and the first and second switches are open.

[0020] As a preferred technical solution, when the circuit is in the seventh connection state, the fourth and fifth switches are disconnected; the voltage detection port is connected to a detection device, and the detection device collects voltage for fault diagnosis.

[0021] As a preferred technical solution, the three-phase motor is a permanent magnet synchronous motor with a star connection.

[0022] Compared with the prior art, the present invention has the following beneficial effects.

[0023] 1) Any two phase windings of the three-phase motor of this utility model are connected to the fourth and fifth switches of the charging switching module. Controlling the closing of the fourth and fifth switches allows the charging pile module to either boost-charge the battery pack module through the three-phase motor or directly charge the battery pack module, satisfying two charging modes. Switching the fourth and fifth switches can also change the distribution of the charging current, reducing the temperature rise of local windings in the motor. Both the fourth and fifth switches can achieve charging, enhancing the robustness of the circuit. The first inductor can be used for energy storage. Detection through the voltage detection port can determine the health status of the charging switch before charging and during normal vehicle operation, ensuring the high-voltage safety of the charging circuit.

[0024] 2) When this utility model is in the first connection state, voltage detection is performed through the voltage detection port to determine the health status of the fourth and fifth switches.

[0025] 3) When the present invention is in the second connection state, the battery pack module is directly charged.

[0026] 4) When this utility model is in the third connection state, it is in BUCK step-down working mode. The circuit forms a step-down loop to charge the first capacitor in order to achieve the charging handshake voltage.

[0027] 5) When this utility model is in the fourth connection state, it is in BOOST boost working mode. The fourth switch device closes first, and the charging pile performs inductive energy storage charging; then the fourth switch device opens, the third switch device closes, and the charging pile module and inductive energy storage are used together to charge the battery pack module.

[0028] 6) When this utility model is in the fifth connection state, the fourth switch is disconnected, so that phase B is connected in parallel with phase A, which can limit the charging current of phase B and avoid the temperature of phase B winding of the three-phase motor being too high.

[0029] 7) When this utility model is in the sixth connection state, the fifth switch is disconnected, so that phase B and phase C are connected in parallel, which can limit the charging current of phase C and avoid the temperature of phase C winding of the three-phase motor being too high.

[0030] 8) When this utility model is in the seventh connection state, the fourth and fifth switches can be disconnected when the three-phase motor is working normally, and the working status of the fourth and fifth switches can be detected in real time. Attached Figure Description

[0031] Figure 1 This is a structural diagram of Embodiment 1 of the high-voltage charging circuit for electric vehicles according to this utility model.

[0032] Figure 2 This is a structural diagram of Embodiment 2 of the high-voltage charging circuit for electric vehicles according to this utility model.

[0033] Figure 3 This is a schematic diagram of the charging circuit of this utility model in the second connection state.

[0034] Figure 4 This is a schematic diagram of the charging circuit of this utility model in the third connection state.

[0035] Figure 5 This is a schematic diagram of the charging circuit of this utility model in the fourth connection state.

[0036] Figure 6 This is a schematic diagram of the charging circuit of this utility model in the fifth connection state.

[0037] Figure 7 This is a schematic diagram of the charging circuit of this utility model in the sixth connection state.

[0038] The numbers in the diagram are as follows:

[0039] 1. Battery pack module; 10. Battery; 11. First switch; 12. Second switch; 2. Energy conversion module; 20. Three-phase motor; 211. First switching device; 212. Second switching device; 213. Third switching device; 214. Fourth switching device; 215. Fifth switching device; 216. Sixth switching device; 3. Charging switching module; 30. Fourth switch; 31. Fifth switch; 32. First capacitor; 33. First inductor; 4. Charging pile module; 5. Voltage detection port; 6. Third switch. Detailed Implementation

[0040] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present utility model.

[0041] Example 1

[0042] like Figure 1 As shown, this utility model provides a high-voltage charging circuit for electric vehicles, including a battery pack module 1, an energy conversion module 2, a charging switching module 3, and a charging pile module 4. A voltage detection port 5 is installed between the charging switching module 3 and the charging pile module 4. The main purpose of this utility model is to solve the problem of excessive motor temperature rise caused by a large voltage difference between the charging pile and the battery pack 10 during the Boost charging process of the high-voltage battery pack 10 in electric vehicles, when the boost duty cycle is large; and to monitor the charging switch in real time, implementing a redundant circuit for charging in the event of partial failure of the charging switch, thereby improving the robustness of the charging system.

[0043] The battery pack module 1 includes a battery 10, a first switch 11, and a second switch 12. The two ends of the battery 10 are respectively connected to one end of the first switch 11 and the second switch 12. The first switch 11 is a main positive relay switch, and the second switch 12 is a main negative relay switch.

[0044] Energy conversion module 2 is used to convert the voltage of battery pack module 1 to the target range of charging pile module 4 at the moment of contact with the charging gun, completing the charging handshake. After the charging handshake is completed, the voltage of charging pile module 4 is increased to the voltage of battery pack module 1 using the first inductor 33 and the motor inductor to charge battery pack 10. Energy conversion module 2 includes a three-phase motor 20 and a three-phase full-bridge inverter. The three-phase full-bridge inverter includes three bridge arms, each of which includes two switching devices, for a total of six switching devices. The first bus terminal of the three-phase full-bridge inverter is connected to the first switch 11, and the second bus terminal is connected to the second switch 12. The three-phase windings of the three-phase motor 20 are respectively connected to the midpoints of the three bridge arms; wherein, the three phases of the three-phase motor 20 are phase A, phase B, and phase C, phase A is connected to the fourth switch 30, and phase C is connected to the fifth switch 31. The switching devices are SiC-MOSFET switches.

[0045] The three-phase motor 20 is a permanent magnet synchronous motor with a star connection.

[0046] The charging switching module 3 includes a fourth switch 30, a fifth switch 31, a first capacitor 32, and a first inductor 33. The fourth switch 30 and the fifth switch 31 are charging switches, the first inductor 33 is a charging auxiliary inductor, and the first capacitor 32 is a charging port capacitor. One end of the fourth switch 30 is connected to phase A of the three-phase motor 20, and the other end is connected to one end of the first inductor 33. One end of the fifth switch 31 is connected to phase C of the three-phase motor 20, and the other end is connected to one end of the first inductor 33. The fourth switch 30 and the fifth switch 31 are connected to the same end of the first inductor 33. The other end of the first inductor 33 is connected to one end of the first capacitor 32 and one end of the charging pile module 4. The other end of the first capacitor 32 is connected to the other end of the charging pile module 4 and the second busbar.

[0047] Before charging begins, the charging circuit is in its first connection state, i.e., the first switch 11 and the second switch 12 are closed, and one of the fourth switch 30 and the fifth switch 31 is closed. The voltage detection port 5 is connected to a detection device. When the fourth switch 30 is closed, the first switching device 211 is intermittently switched on and off to detect whether the voltage can maintain the target voltage at the charging port. When the fifth switch 31 is closed, the fifth switching device 215 is intermittently switched on and off to detect whether the voltage can maintain the target voltage at the charging port. The health status of the fourth switch 30 and the fifth switch 31 is determined by the voltage. If they can maintain the target voltage, it proves that the fourth switch 30 and the fifth switch 31 are healthy. The vehicle and BMS controllers use the voltage detection port 5 to detect the voltage and determine whether to enter direct charging mode or boost charging mode based on the voltage of the 10 battery packs. If the charging port voltage is higher than the voltage of the 10 battery packs, the charging pile directly charges the 10 battery packs through diodes and SiC-MOSFET switches. If the charging port voltage is lower than the voltage of the 10 battery packs, the vehicle and BMS controllers control the motor controller to enter the BUCK step-down working mode.

[0048] like Figure 3 As shown, the charging circuit is in the second connection state, i.e., direct charging. The arrows in the diagram indicate the direction of current. First switch 11, second switch 12, fourth switch 30, and fifth switch 31 are closed, while first switch device 211, second switch device 212, third switch device 213, fourth switch device 214, fifth switch device 215, and sixth switch device 216 are open. This scheme allows the charging pile to directly charge the battery pack 10 through the anti-parallel diodes of first switch device 211 and fifth switch device 215, along with fourth switch 30, fifth switch 31, and first inductor 33, forming a direct charging circuit. A separate switching circuit for direct charging is no longer required.

[0049] like Figure 4 As shown, the charging circuit is in the third connection state, i.e., the BUCK step-down mode. The arrows in the diagram indicate the current direction. Switches 11, 12, 30, and 31 are closed, while switches 212, 213, 214, and 216 are open. Switches 211 and 215 are closed intermittently. Switches 211 and 215, together with the first inductor 33, form a step-down circuit to charge the first capacitor 32. After reaching the handshake voltage at the charging port, the circuit then enters the BOOST step-up mode.

[0050] like Figure 5 As shown, the charging circuit is in the fourth connection state, i.e., BOOST boost mode. The arrows in the diagram indicate the current direction. Switches 11, 12, 30, and 31 are closed; switches 211, 212, 215, and 216 are open; one of switches 213 and 214 is closed, and they operate alternately. The B-phase inductor of the three-phase motor 20, the fourth switch 30, the A-phase inductor connected in parallel with the fifth switch 31, the C-phase inductor, and the first inductor 33 form a Boost boost circuit, charging the battery pack 10 from the charging pile. Switch 214 closes first, and the charging pile charges the inductor's energy storage. Then, switch 214 opens, and switch 213 closes, allowing the inductor and charging pile to jointly charge the battery pack.

[0051] like Figure 6As shown, when the temperature of the B-phase winding of the three-phase motor 20 is high, the charging current is limited, so that the charging circuit is in the fifth connection state. The arrow in the figure indicates the direction of the current. The first switch 11, the second switch 12 and the fifth switch 31 remain closed, the fourth switch 30 is opened, the first switch device 211 and the second switch device 212 are closed alternately, the third switch device 213 and the fourth switch device 214 are closed alternately, the fifth switch device 215 and the sixth switch device 216 are opened, and the first switch device 211 and the second switch device 212, as well as the third switch device 213 and the fourth switch device 214 are turned on alternately, forming a two-parallel and two-series scheme. The first inductor 33, the fifth switch 31, the C-phase inductor and the A and B phase inductors connected in parallel form a Boost boost mode.

[0052] like Figure 7 As shown, when the temperature of the C-phase inductor of the three-phase motor 20 is high, the charging current is limited, so that the charging circuit is in the sixth connection state. The arrow in the figure indicates the direction of the current. The first switch 11, the second switch 12 and the fourth switch 30 remain closed, the fifth switch 31 is opened, the third switch device 213 and the fourth switch device 214 are closed alternately, the fifth switch device 215 and the sixth switch device 216 are closed alternately, the first switch device 211 and the second switch device 212 are opened, forming a new two-parallel and two-series scheme, which is a Boost boost mode composed of the first inductor 33, the fourth switch 30, the A-phase inductor connected in parallel with the B and C-phase inductors.

[0053] During Boost charging, the fourth switch 30 or the fifth switch 31 is activated based on the current electrical angle position of the motor. This reduces motor rotation caused by the redistribution of winding current. Switching the charging switch changes the distribution of charging current, reducing the problem of excessive temperature rise in certain motor windings. This invention can alleviate the problem of excessive temperature rise caused by high current in a particular winding, balance the heating of the three-phase motor windings, and extend the charging time.

[0054] From the perspective of the reliability of the charging system, the fourth switch 30 and the fifth switch 31 are designed to be redundant. If one of them fails, the other can be used for charging, which enhances the robustness of the system.

[0055] From a safety perspective, when the three-phase motor 20 is working normally (without charging), the charging circuit is in the seventh connection state, the fourth switch 30 and the fifth switch 31 are disconnected, the voltage detection port 5 is connected to the detection equipment, the voltage of the voltage detection port 5 is monitored in real time, and the health status of the fourth switch 30 and the fifth switch 31 is detected to ensure the high voltage safety of the charging circuit.

[0056] Example 2

[0057] like Figure 2As shown, this utility model provides a high-voltage charging circuit for electric vehicles, including a battery pack module 1, an energy conversion module 2, a charging switching module 3, and a charging pile module 4.

[0058] Unlike Embodiment 1, the battery pack module 1 and the charging pile module 4 are connected to the first bus terminal via a third switch 6.

[0059] Closing the third switch 6 enables the charging pile module 4 to directly charge the battery pack module 1.

[0060] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A high-voltage charging circuit for electric vehicles, characterized in that, It includes a battery pack module (1), an energy conversion module (2), a charging switching module (3), and a charging pile module (4); a voltage detection port (5) is installed between the charging switching module (3) and the charging pile module (4); The battery pack module (1) includes a battery (10), a first switch (11), and a second switch (12); the first switch (11) and the second switch (12) are respectively connected to the two ends of the battery (10); The energy conversion module (2) includes a three-phase motor (20) and a three-phase full-bridge inverter. The three-phase full-bridge inverter includes six switching devices, which form three bridge arms. Each bridge arm includes two switching devices. The three-phase windings of the three-phase motor (20) are respectively connected to the midpoints of the three bridge arms. The first bus terminal of the three-phase full-bridge inverter is connected to the first switch (11), and the second bus terminal is connected to the second switch (12). The charging switching module (3) includes a fourth switch (30), a fifth switch (31), a first capacitor (32), and a first inductor (33); one end of the fourth switch (30) and the fifth switch (31) are respectively connected to two phases of the three-phase winding, and the other end is connected to one end of the first inductor (33). The other end of the first inductor (33) is connected to one end of the first capacitor (32) and one end of the charging pile module (4); the other end of the first capacitor (32) is connected to the other end of the charging pile module (4) and the second bus terminal.

2. The high-voltage charging circuit for an electric vehicle according to claim 1, characterized in that, The bridge arm includes a first bridge arm, a second bridge arm, and a third bridge arm. The first bridge arm includes a first switching device (211) and a second switching device (212). The second bridge arm includes a third switching device (213) and a fourth switching device (214). The third bridge arm includes a fifth switching device (215) and a sixth switching device (216). The three-phase winding includes phase A, phase B, and phase C. The inductance of phase A is connected to the midpoint of the first bridge arm. The inductance of phase B is connected to the midpoint of the second bridge arm. The inductance of phase C is connected to the midpoint of the third bridge arm. The fourth switch (30) is connected between the inductance of phase A and the midpoint of the first bridge arm, and the fifth switch (31) is connected between the inductance of phase C and the midpoint of the third bridge arm.

3. The high-voltage charging circuit for an electric vehicle according to claim 2, characterized in that, When the circuit is in the first connection state, the first switch (11) and the second switch (12) are closed, and one of the fourth switch (30) and the fifth switch (31) is closed; when the fourth switch (30) is closed, the first switching device (211) is switched on and off intermittently, and when the fifth switch (31) is closed, the fifth switching device (215) is switched on and off intermittently; the voltage detection port (5) is connected to the detection device.

4. The high-voltage charging circuit for an electric vehicle according to claim 2, characterized in that, When the circuit is in the second connection state, the first switch (11), the second switch (12), the fourth switch (30) and the fifth switch (31) are closed, and the first switch device (211), the second switch device (212), the third switch device (213), the fourth switch device (214), the fifth switch device (215) and the sixth switch device (216) are open.

5. The high-voltage charging circuit for an electric vehicle according to claim 2, characterized in that, When the circuit is in the third connection state, the first switch (11), the second switch (12), the fourth switch (30) and the fifth switch (31) are closed; the second switch device (212), the third switch device (213), the fourth switch device (214) and the sixth switch device (216) are open, and the first switch device (211) and the fifth switch device (215) are closed at intervals.

6. The electric vehicle high-voltage charging circuit according to claim 2, characterized in that, When the circuit is in the fourth connection state, the first switch (11), the second switch (12), the fourth switch (30) and the fifth switch (31) are closed; the first switch device (211), the second switch device (212), the fifth switch device (215) and the sixth switch device (216) are open; and one of the third switch device (213) and the fourth switch device (214) is closed.

7. The high-voltage charging circuit for an electric vehicle according to claim 2, characterized in that, When the circuit is in the fifth connection state, the first switch (11) and the second switch (12) are closed, the fourth switch (30) is open, the fifth switch (31) is closed, the first switch device (211) and the second switch device (212) are closed alternately, the third switch device (213) and the fourth switch device (214) are closed alternately, and the fifth switch device (215) and the sixth switch device (216) are open.

8. A high-voltage charging circuit for an electric vehicle according to claim 2, characterized in that, When the circuit is in the sixth connection state, the first switch (11) and the second switch (12) are closed, the fourth switch (30) is closed, the fifth switch (31) is open, the third switch device (213) and the fourth switch device (214) are closed alternately, the fifth switch device (215) and the sixth switch device (216) are closed alternately, and the first switch device (211) and the second switch device (212) are open.

9. A high-voltage charging circuit for an electric vehicle according to claim 1, characterized in that, When the circuit is in the seventh connection state, the fourth switch (30) and the fifth switch (31) are disconnected; the voltage detection port (5) is connected to the detection device, and the detection device collects voltage for fault diagnosis.

10. A high-voltage charging circuit for an electric vehicle according to claim 1, characterized in that, The three-phase motor (20) is a permanent magnet synchronous motor with a star connection.

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