Charging system and electric vehicle

Abstract

The invention provides a charging system and an electric vehicle, the charging system comprises a motor controller MCU and a first inductor, a first bridge arm in the MCU and the first inductor form a voltage conversion circuit, when the power supply voltage is smaller than the minimum charging voltage of a power battery, the MCU can carry out boost conversion on the power supply voltage through the voltage conversion circuit, and then the power battery is charged. The power supply voltage after boosting conversion is used as first output voltage to be output to the power battery, and the first output voltage is not less than the minimum charging voltage. While the charging system is utilized to carry out voltage reduction conversion on the power supply voltage, the occupied space and the cost of the charging system are reduced.

Description

[0001] This application is a divisional application. The application number of the original application is 202110083917.2, and the original application date is January 21, 2021. The entire content of the original application is incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of new energy vehicle technology, and in particular to a charging system and an electric vehicle. Background Art

[0003] With the development of new energy technologies, electric vehicles have gained increasing attention. Electric vehicles are equipped with power batteries that receive and store electricity provided by charging stations. During the driving process, the power batteries release the stored energy to drive the electric vehicle.

[0004] To increase charging speeds, more and more electric vehicles are using 800V high-voltage power batteries. The maximum voltage of a power battery is 800V, and the required charging voltage can exceed 800V. However, most DC fast chargers currently on the market have an output voltage of 500V and are unable to directly charge 800V high-voltage power batteries. This makes charging difficult for electric vehicles equipped with high-voltage power batteries, hindering the user experience.

[0005] Therefore, the charging scheme for electric vehicles still needs further research. Summary of the Invention

[0006] In view of this, the present application provides a charging system and an electric vehicle, which are beneficial for the electric vehicle to still support the power supply voltage to charge the power battery when the power supply voltage is lower than the minimum charging voltage of the power battery.

[0007] In a first aspect, the present application provides a charging system comprising a motor controller (MCU) and a first inductor. The MCU includes N bridge arms, where N is an integer greater than or equal to 1. The high-potential ends of the N bridge arms are connected to a first power supply terminal and a first battery terminal of the charging system. The first power supply terminal can be connected to the positive electrode of a DC power supply, and the first battery terminal can be connected to the positive electrode of a power battery. The DC power supply can output a power supply voltage, and the power battery can receive a first output voltage of the charging system. The low-potential ends of the N bridge arms are connected to a second battery terminal of the charging system, and the second battery terminal can be connected to the negative electrode of the power battery. One end of the first inductor is connected to the second power supply terminal, and the other end of the first inductor is connected to the midpoint of the first bridge arm. The second power supply terminal can be connected to the negative electrode of the DC power supply. The first bridge arm can be any of the N bridge arms. The N bridge arms of the MCU and the first inductor constitute a voltage conversion circuit. When the power supply voltage is less than the minimum charging voltage of the power battery, the MCU can perform a voltage conversion on the power supply voltage through the voltage conversion circuit and output the boosted power voltage as a first output voltage to the power battery. The first output voltage is not less than the minimum charging voltage.

[0008] In summary, this application implements a charging system by reusing an MCU. When the power supply voltage is less than the minimum charging voltage of the power battery, the charging system can step up the power supply voltage to obtain a first output voltage that is not less than the minimum charging voltage. This first output voltage is compatible with the power battery, thereby charging the power battery. Furthermore, by reusing the MCU commonly found in electric vehicles, this application also helps reduce the space and cost of the charging system.

[0009] For example, the first aspect of this application provides the following examples for illustration:

[0010] Example 1

[0011] The first bridge arm includes a first switching transistor and a second switching transistor. The first electrode of the first switching transistor is connected to the first battery terminal and the first power supply terminal, respectively, and the second electrode of the first switching transistor is connected to the first electrode of the second switching transistor. The midpoint of the first bridge arm is located between the first and second switching transistors. When the power supply voltage is less than the minimum charging voltage, the MCU can turn on the first switching transistor to charge the first inductor. The MCU can turn off the first switching transistor to discharge the first inductor.

[0012] Specifically, when the MCU turns on the first switching tube, current is output from the positive electrode of the DC power supply, passes through the first switching tube, and reaches the first inductor, charging the first inductor. When the MCU turns off the first switching tube, the first inductor begins to discharge. Current is output from the end of the first inductor closest to the second power supply, transmitted through the DC power supply, power battery, and the diode in the second switching tube, and then flows back to the end of the first inductor closest to the second switching tube. During this process, the DC power supply and the first inductor discharge in series, and the first output voltage is the sum of the power supply voltage and the voltage of the first inductor. Obviously, the first output voltage is greater than the power supply voltage, so step-up conversion can be achieved.

[0013] It is understood that the power supply voltage provided by the DC power supply may also be within the charging voltage range of the power battery, that is, the power supply voltage is adapted to the power battery. To be compatible with this scenario, the charging system in this application may also include a first switch, the first end of which is connected to the second battery terminal, and the second end of the first switch is connected to the second power supply terminal. The MCU can also turn on the first switch when the power supply voltage is within the charging voltage range of the power battery; and turn off the first switch when the power supply voltage is outside the charging voltage range of the power battery.

[0014] Specifically, when the first switch is turned on, the power battery can be directly connected to the DC power supply, so that the power battery can directly receive the power supply voltage provided by the DC power supply to complete charging. Therefore, when the power supply voltage is within the charging voltage range of the power battery, the first switch can be turned on. When the first switch is turned off, the MCU can convert the power supply voltage and provide the converted power supply voltage as the first output voltage to the power battery. Therefore, when the power supply voltage is outside the charging voltage range of the power battery, the first switch can be turned off.

[0015] To accommodate high-power scenarios, the charging system may include N first inductors and N third switches. One end of each of the N third switches is connected to the second power supply terminal, and the other ends of each of the N third switches are connected in a one-to-one correspondence to one end of each of the N first inductors. The other ends of each of the N first inductors are connected in a one-to-one correspondence to each of the N bridge arms. The N third switches can be turned on when receiving power supply voltage and turned off when no longer receiving power supply voltage.

[0016] Specifically, when the N third switches are turned on, the charging and discharging of the N first inductors can be controlled separately through the N bridge arms. In other words, the N first inductors can transmit power in parallel, thus adapting to high-power scenarios. Turning off the N third switches when the power supply voltage stops isolating the N first inductors, thereby isolating the N first inductors from each other, which helps reduce the impact of the N first inductors on the MCU's inverter function.

[0017] Example 2

[0018] It is foreseeable that in some scenarios, the power supply voltage may be greater than the maximum charging voltage of the power battery. In view of this, the MCU in this application can also use the voltage conversion circuit to step down the power supply voltage when the power supply voltage is greater than the maximum charging voltage of the power battery, and output the stepped-down power supply voltage as the first output voltage to the power battery. The first output voltage is no greater than the maximum charging voltage. In this case, the electric vehicle can receive a larger power supply voltage, convert the power supply voltage, and charge the power battery, thereby improving charging convenience.

[0019] Exemplarily, the first bridge arm includes a first switching transistor and a second switching transistor, wherein the first electrode of the first switching transistor is connected to the first battery terminal and the first power supply terminal, respectively, and the second electrode of the first switching transistor is connected to the first electrode of the second switching transistor, with the midpoint of the first bridge arm located between the first switching transistor and the second switching transistor. The charging system may further include a first switch and a second switch, wherein the first end of the first switch is connected to the second battery terminal, the second end of the first switch is connected to the second power supply terminal, the first end of the second switch is connected to the first battery terminal, the second end of the second switch is connected to one end of the first inductor, and the third end of the second switch is connected to the first power supply terminal.

[0020] In this charging system, when the power supply voltage is greater than the maximum charging voltage, the MCU can turn on the first switch and the first and second terminals of the second switch. The MCU turns on the first switch to charge the first inductor and turns off the first switch to discharge the first inductor.

[0021] Specifically, when the MCU turns on the first switch, the first inductor is charged. At this point, the first output voltage is the difference between the power supply voltage and the first inductor voltage. When the MCU turns off the first switch, the first inductor is discharged. At this point, the first output voltage is the first inductor voltage. Therefore, the first output voltage is always lower than the power supply voltage, allowing the charging system to step down the power supply voltage.

[0022] It should be noted that the charging system provided in Example 2 can also perform a step-up conversion on the power supply voltage. Exemplarily, the charging system can further include a third switch, wherein a first end of the third switch is connected to one end of the first inductor, and a second end of the third switch is connected to the second power supply end. When the power supply voltage is less than the minimum charging voltage, the MCU can turn on the first and third ends of the second switch, turn on the third switch, and turn off the first switch. The MCU turns on the first switch tube to charge the first inductor. The MCU turns off the first switch tube to discharge the first inductor.

[0023] Specifically, the MCU turns on the first switch to charge the first inductor. Turning off the first switch allows the first inductor to discharge. At this point, the first output voltage is the sum of the first inductor voltage and the power supply voltage. Therefore, the first output voltage is greater than the power supply voltage, allowing the charging system to boost the power supply voltage.

[0024] In addition, the charging system provided in Example 2 can also perform buck-boost conversion on the power supply voltage. Exemplarily, the charging system may further include a third switch, wherein a first end of the third switch is connected to one end of the first inductor, and a second end of the third switch is connected to the second power supply end. The MCU may turn on the first and second ends of the second switch, and turn on the third switch. The MCU turns on the first switch tube to charge the first inductor. The MCU turns off the first switch tube to discharge the first inductor.

[0025] Specifically, the MCU can charge the first inductor by turning on the first switch. When the MCU turns off the first switch, the first inductor can be discharged. At this time, the first output voltage is the voltage of the first inductor. The voltage of the first inductor depends on the charging time of the first inductor. Therefore, by adjusting the charging time of the first inductor, the magnitude of the first output voltage can be adjusted. The first output voltage can be greater than the power supply voltage (step-up conversion) or less than the power supply voltage (step-down conversion).

[0026] It is understood that the charging system provided in Example 2 of this application is also compatible with scenarios where the power supply voltage matches the power battery. For example, the MCU can also turn on the first and third terminals of the second switch and the first switch when the power supply voltage is within the charging voltage range of the power battery. In this case, the power battery is directly connected to the DC power supply and can directly receive the power supply voltage to complete charging.

[0027] In a second aspect, the present application also provides a charging system, which mainly includes a motor controller MCU and a first inductor. The MCU includes N bridge arms, where N is an integer greater than or equal to 1. The high potential ends of the N bridge arms of the MCU are connected to the first power supply terminal and the first battery terminal of the charging system. The first power supply terminal can be connected to the positive pole of the DC load, and the first battery terminal can be connected to the positive pole of the power battery. The DC load can receive the second output voltage of the charging system, and the power battery can output the battery voltage to the charging system. The low potential ends of the N bridge arms in the MCU are connected to the second battery terminal of the charging system, and the second battery terminal can be connected to the negative pole of the power battery. One end of the above-mentioned first inductor is connected to the second power supply terminal, and the other end of the first inductor is connected to the first bridge arm. The second power supply terminal can be connected to the negative pole of the DC load. The first bridge arm is any bridge arm among the N bridge arms. The first bridge arm and the first inductor constitute a voltage conversion circuit. When the battery voltage is greater than the maximum operating voltage of the DC load, the MCU can step down the battery voltage through the voltage conversion circuit and output the stepped-down battery voltage as a second output voltage to the DC load. The second output voltage is no greater than the maximum operating voltage.

[0028] In summary, this application implements a charging system by reusing an MCU. When the battery voltage is greater than the maximum operating voltage of the DC load, the charging system can step down the battery voltage to obtain a second output voltage no greater than the aforementioned maximum operating voltage. This second output voltage can adapt to the DC load, thereby providing power to the DC load. Furthermore, by reusing the MCU commonly found in electric vehicles, this application also helps reduce the space and cost of the charging system.

[0029] For example, the second aspect of this application provides the following examples for illustration:

[0030] Example 1

[0031] Exemplarily, the first bridge arm includes a first switching tube and a second switching tube, wherein a first electrode of the first switching tube is connected to the first battery terminal and the first power supply terminal, respectively, and a second electrode of the first switching tube is connected to the first electrode of the second switching tube. The midpoint of the first bridge arm is located between the first switching tube and the second switching tube. When the battery voltage is greater than the maximum operating voltage, the MCU can turn on the second switching tube to charge the first inductor. The MCU can turn off the second switching tube to discharge the first inductor.

[0032] Specifically, after the MCU turns on the second switch, the first inductor can be charged. At this point, the first output voltage is the voltage difference between the power supply voltage and the voltage of the first inductor. After the MCU turns off the second switch, the first inductor can be discharged. At this point, the first output voltage is the voltage of the first inductor. As can be seen, the first output voltage is always lower than the battery voltage. Therefore, the charging system provided in Example 1 of this application can achieve step-down conversion of the battery voltage.

[0033] It is understood that the battery voltage of the power battery may also be adapted to the DC load. To accommodate this scenario, the charging system may further include a first switch, wherein a first terminal of the first switch is connected to the second battery terminal, and a second terminal of the first switch is connected to the second power supply terminal. The MCU may also turn on the first switch when the battery voltage is within the operating voltage range of the DC load; and turn off the first switch when the battery voltage is outside the operating voltage range of the DC load.

[0034] When the first switch is on, the power battery can be directly connected to the DC load and directly power the DC load. When the first switch is off, the MCU can convert the battery voltage and provide the converted battery voltage as the second output voltage to the DC load.

[0035] To accommodate high-power scenarios, the charging system may include N first inductors and N third switches. One end of each of the N third switches is connected to the second power supply terminal, and the other ends of each of the N third switches are connected in a one-to-one correspondence to one end of each of the N first inductors. The other ends of each of the N first inductors are connected in a one-to-one correspondence to each of the N bridge arms. The N third switches can be turned on when the second output voltage is being output and turned off when the second output voltage is no longer being output.

[0036] Specifically, when the N third switches are turned on, the charging and discharging of the N first inductors can be controlled separately through the N bridge arms. In other words, the N first inductors can transmit power in parallel, thus adapting to high-power scenarios. Turning off the N third switches when the power supply voltage stops isolating the N first inductors, thereby isolating the N first inductors from each other, which helps reduce the impact of the N first inductors on the MCU's inverter function.

[0037] Example 2

[0038] It is foreseeable that in some scenarios, the battery voltage may be lower than the minimum operating voltage of the DC load. In view of this, the MCU in this application can also step up the battery voltage through the voltage conversion circuit when the battery voltage is lower than the minimum operating voltage of the DC load, and output the stepped-up battery voltage as a second output voltage to the DC load, where the second output voltage is no less than the minimum operating voltage.

[0039] Exemplarily, the first bridge arm in the MCU includes a first switching transistor and a second switching transistor, wherein the first electrode of the first switching transistor is connected to the first battery terminal and the first power supply terminal, respectively, and the second electrode of the first switching transistor is connected to the first electrode of the second switching transistor, with the midpoint of the first bridge arm located between the first switching transistor and the second switching transistor. The charging system may further include a first switch and a second switch, wherein the first end of the first switch is connected to the second battery terminal, the second end of the first switch is connected to the second power supply terminal, the first end of the second switch is connected to the first battery terminal, the second end of the second switch is connected to one end of the first inductor, and the third end of the second switch is connected to the first power supply terminal.

[0040] In this charging system, when the battery voltage is less than the minimum operating voltage, the MCU can turn on the first switch and the first and second terminals of the second switch. The MCU turns on the second switch to charge the first inductor. The MCU turns off the second switch to discharge the first inductor.

[0041] Specifically, the MCU turns on the second switch to charge the first inductor. Turning off the second switch allows the first inductor to discharge. At this point, the second output voltage is the sum of the battery voltage and the voltage across the first inductor. This indicates that the second output voltage is greater than the battery voltage, allowing the charging system to boost the battery voltage.

[0042] It should be noted that the charging system provided in Example 2 can also perform step-down conversion on the battery voltage. Exemplarily, the charging system can further include a third switch, wherein a first end of the third switch is connected to one end of the first inductor, and a second end of the third switch is connected to the second power supply end. When the battery voltage is greater than the maximum operating voltage, the MCU can turn on the first and third ends of the second switch, turn on the third switch, and turn off the first switch. The MCU turns on the second switch tube to charge the first inductor. The MCU turns off the second switch tube to discharge the first inductor.

[0043] Specifically, when the MCU turns on the second switch, the first inductor is charged, and the second output voltage is the difference between the battery voltage and the first inductor voltage. When the MCU turns off the second switch, the first inductor is discharged, and the second output voltage is the first inductor voltage. Therefore, the second output voltage is always lower than the battery voltage, allowing the charging system to step down the battery voltage.

[0044] In addition, the charging system provided in Example 2 can also perform buck-boost conversion on the battery voltage. Exemplarily, the charging system may further include a third switch, wherein a first end of the third switch is connected to one end of the first inductor, and a second end of the third switch is connected to the second power supply end. The MCU may turn on the first and second ends of the second switch, and turn on the third switch. The MCU turns on the second switch tube to charge the first inductor. The MCU turns off the second switch tube to discharge the first inductor.

[0045] Specifically, the MCU turns on the second switch to charge the first inductor. Turning off the second switch allows the first inductor to discharge, at which point the second output voltage equals the voltage of the first inductor. The voltage of the first inductor depends on the duration of its charging. Therefore, adjusting the duration of the first inductor's charging can adjust the second output voltage. This second output voltage can be greater than the battery voltage (for step-up conversion) or less than the battery voltage (for step-down conversion).

[0046] It is understood that the charging system provided in Example 2 of this application is also compatible with scenarios where the battery voltage matches the DC load. For example, the MCU can also turn on the first and third terminals of the second switch and the first switch when the battery voltage is within the operating voltage range of the power battery. In this case, the power battery is directly connected to the DC load and can directly power the DC load.

[0047] In a third aspect, the present application provides a charging system, which mainly includes a motor controller MCU and a first inductor. The MCU includes N bridge arms, where N is an integer greater than or equal to 1. The high potential ends of the N bridge arms are connected to the first battery terminal of the charging system, the first battery terminal can be connected to the positive pole of the power battery, and the power battery can receive the first output voltage of the charging system. The low potential ends of the N bridge arms are connected to the second battery terminal and the second power supply terminal of the charging system, the second battery terminal can be connected to the negative pole of the power battery, the second power supply terminal can be connected to the negative pole of the DC power supply, and the DC power supply can output the power supply voltage. One end of the first inductor is connected to the first power supply terminal, and the other end of the first inductor is connected to the middle point of the first bridge arm. The first power supply terminal can be connected to the positive pole of the DC power supply, and the first bridge arm is any one of the N bridge arms. The first bridge arm and the first inductor constitute a voltage conversion circuit. When the power supply voltage is lower than the minimum charging voltage of the power battery, the MCU can perform a voltage conversion on the power supply voltage through the voltage conversion circuit, and output the power supply voltage after the voltage conversion as a first output voltage to the power battery, and the first output voltage is not lower than the minimum charging voltage; when the power supply voltage is higher than the maximum charging voltage of the power battery, the MCU can perform a voltage conversion on the power supply voltage through the voltage conversion circuit, and output the power supply voltage after the voltage conversion as a first output voltage to the power battery, and the first output voltage is not higher than the minimum charging voltage.

[0048] Exemplarily, the first bridge arm includes a first switching transistor and a second switching transistor, wherein the first electrode of the first switching transistor is connected to the first battery terminal and the first power supply terminal, respectively, and the second electrode of the first switching transistor is connected to the first electrode of the second switching transistor, with the midpoint of the first bridge arm located between the first switching transistor and the second switching transistor. The charging system also includes a sixth switch and a fifth switch, wherein the first end of the fifth switch is connected to the second battery terminal, the second end of the fifth switch is connected to the low potential end of the N bridge arms, the third end of the fifth switch is connected to one end of the first inductor, the first end of the sixth switch is connected to the first battery terminal, and the second end of the sixth switch is connected to the first power supply terminal.

[0049] When the power supply voltage is greater than the maximum charging voltage, the MCU can turn on the sixth switch, turn on the first terminal and the third terminal of the fifth switch, turn on the second switch tube to charge the first inductor, and turn off the second switch tube to discharge the first inductor.

[0050] Specifically, when the MCU turns on the second switch, the first inductor is charged, and the first output voltage is the difference between the power supply voltage and the first inductor voltage. When the MCU turns off the second switch, the first inductor is discharged, and the first output voltage is the first inductor voltage. Therefore, the first output voltage is always lower than the power supply voltage, allowing the charging system to step down the power supply voltage.

[0051] It should be noted that the charging system provided in the third aspect of the present application can also perform a step-up conversion on the power supply voltage. Exemplarily, the charging system may further include a fourth switch, wherein the first end of the fourth switch is connected to one end of the first inductor, and the second end of the fourth switch is connected to the first power supply end. When the power supply voltage is less than the minimum charging voltage, the MCU can turn on the first and second ends of the fifth switch, turn on the fourth switch, and turn off the sixth switch. The MCU turns on the second switch tube to charge the first inductor. The MCU turns off the second switch tube to discharge the first inductor.

[0052] Specifically, the MCU turns on the second switch to charge the first inductor. Turning off the second switch allows the first inductor to discharge. At this point, the first output voltage is the sum of the first inductor voltage and the power supply voltage. This indicates that the first output voltage is greater than the power supply voltage, allowing the charging system to boost the power supply voltage.

[0053] In addition, the charging system provided in the third aspect of the present application can also perform buck-boost conversion on the power supply voltage. Exemplarily, the charging system may further include a fourth switch, wherein the first end of the fourth switch is connected to one end of the first inductor, and the second end of the fourth switch is connected to the first power supply end. The MCU may turn on the first end and the third end of the fifth switch, and turn on the fourth switch. The MCU turns on the second switch tube to charge the first inductor. The MCU turns off the second switch tube to discharge the first inductor.

[0054] Specifically, the MCU turns on the second switch to charge the first inductor. Turning off the second switch allows the first inductor to discharge, at which point the first output voltage is the voltage of the first inductor. The voltage of the first inductor depends on the duration of the first inductor's charging. Therefore, adjusting the duration of the first inductor's charging can adjust the first output voltage. This first output voltage can be greater than the power supply voltage (for step-up conversion) or less than the power supply voltage (for step-down conversion).

[0055] It is understood that the charging system provided in the third aspect of this application is also compatible with scenarios where the power supply voltage matches the power battery. For example, the MCU can also turn on the first and second terminals of the fifth switch and the sixth switch when the power supply voltage is within the charging voltage range of the power battery. In this case, the power battery is directly connected to the DC power supply and can directly receive the power supply voltage to complete charging.

[0056] In a fourth aspect, the present application provides a charging system, which mainly includes a motor controller MCU and a first inductor. The MCU includes N bridge arms, where N is an integer greater than or equal to 1. The high potential ends of the N bridge arms are connected to the first battery terminal of the charging system, the first battery terminal can be connected to the positive pole of the power battery, and the power battery can output the battery voltage to the charging system. The low potential ends of the N bridge arms are connected to the second battery terminal and the second power supply terminal of the charging system, the second battery terminal can be connected to the negative pole of the power battery, the second power supply terminal can be connected to the negative pole of the DC load, and the DC load can receive the second output voltage of the charging system. One end of the first inductor is connected to the first power supply terminal, and the other end of the first inductor is connected to the middle point of the first bridge arm. The first power supply terminal can be connected to the positive pole of the DC load. The first bridge arm is any one of the N bridge arms. The first bridge arm and the first inductor can form a voltage conversion circuit. When the battery voltage is greater than the maximum operating voltage of the DC load, the MCU can perform a step-down conversion on the battery voltage through the voltage conversion circuit, and output the battery voltage after the step-down conversion as a second output voltage to the DC load, and the second output voltage is not greater than the maximum operating voltage; when the battery voltage is less than the minimum operating voltage of the DC load, the battery voltage can be stepped up through the voltage conversion circuit, and output the battery voltage after the step-up conversion as a second output voltage to the DC load, and the second output voltage is not less than the minimum operating voltage.

[0057] Exemplarily, the first bridge arm of the MCU includes a first switching transistor and a second switching transistor, wherein the first electrode of the first switching transistor is connected to the first battery terminal and the first power supply terminal, respectively, and the second electrode of the first switching transistor is connected to the first electrode of the second switching transistor, with the midpoint located between the first switching transistor and the second switching transistor. The charging system also includes a sixth switch and a fifth switch, wherein the first end of the fifth switch is connected to the second battery terminal, the second end of the fifth switch is connected to the low potential end of the N bridge arms, the third end of the fifth switch is connected to one end of the first inductor, the first end of the sixth switch is connected to the first battery terminal, and the second end of the sixth switch is connected to the first power supply terminal.

[0058] In this charging system, when the battery voltage is less than the minimum operating voltage, the MCU can turn on the sixth switch, thereby connecting the first and third terminals of the fifth switch. The MCU also turns on the first switch to charge the first inductor. The MCU then turns off the first switch to discharge the first inductor.

[0059] Specifically, the MCU turns on the first switch to charge the first inductor. Turning off the first switch allows the first inductor to discharge. At this point, the second output voltage is the sum of the battery voltage and the voltage of the first inductor. Therefore, the second output voltage is greater than the battery voltage, allowing the charging system to boost the battery voltage.

[0060] It should be noted that the charging system provided in the fourth aspect of the present application can also perform a step-down conversion on the battery voltage. Exemplarily, the charging system may further include a fourth switch, a first end of the fourth switch being connected to one end of the first inductor, and a second end of the fourth switch being connected to the first power supply end. When the battery voltage is greater than the maximum operating voltage, the MCU may turn on the first and second ends of the fifth switch, turn on the fourth switch, and turn off the sixth switch. The MCU turns on the second switch tube to charge the first inductor. The MCU turns off the second switch tube to discharge the first inductor.

[0061] Specifically, when the MCU turns on the first switch, the first inductor is charged, and the second output voltage is the difference between the battery voltage and the first inductor voltage. When the MCU turns off the first switch, the first inductor is discharged, and the second output voltage is the first inductor voltage. Therefore, the second output voltage is always lower than the battery voltage, allowing the charging system to step down the battery voltage.

[0062] In addition, the charging system provided in the fourth aspect of the present application can also perform buck-boost conversion on the battery voltage. Exemplarily, the charging system may further include a fourth switch, a first end of the fourth switch being connected to one end of the first inductor, and a second end of the fourth switch being connected to the first power supply end. The MCU may turn on the first end and the third end of the fifth switch, and turn on the fourth switch. The MCU turns on the first switch tube to charge the first inductor. The MCU turns off the first switch tube to discharge the first inductor.

[0063] Specifically, the MCU turns on the first switch to charge the first inductor. Turning off the first switch allows the first inductor to discharge, at which point the second output voltage is the voltage of the first inductor. The voltage of the first inductor depends on the duration of its charging. Therefore, adjusting the duration of the first inductor's charging can adjust the second output voltage. This second output voltage can be greater than the battery voltage (for step-up conversion) or less than the battery voltage (for step-down conversion).

[0064] It is understood that the charging system provided in the fourth aspect of the present application is also compatible with scenarios where the battery voltage matches the DC load. For example, the MCU may also turn on the first and second terminals of the fifth switch and the sixth switch when the battery voltage is within the operating voltage range of the DC load. In this case, the power battery is directly connected to the DC load and can directly power the DC load.

[0065] In a fifth aspect, the present application provides an electric vehicle, which mainly includes a power battery and a charging system as provided in any one of the first to fourth aspects above, and the charging system can charge the power battery.

[0066] These and other aspects of the present application will become more readily apparent from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic diagram of an electric vehicle charging scenario;

[0068] Figure 2 is a schematic diagram of an electric drive system;

[0069] Figure 3 A schematic diagram of a charging system provided in an embodiment of the present application;

[0070] Figure 4 This is one of the boost conversion states of the charging system provided in the embodiment of the present application;

[0071] Figure 5 This is the second boost conversion state of the charging system provided in the embodiment of the present application;

[0072] Figure 6 A schematic diagram of a specific charging system provided in an embodiment of the present application;

[0073] Figure 7 A schematic diagram of a specific charging system provided in an embodiment of the present application;

[0074] Figure 8 This is one of the step-down conversion states of the charging system provided in the embodiment of the present application;

[0075] Figure 9 This is the second step-down conversion state of the charging system provided in the embodiment of the present application;

[0076] Figure 10 A schematic diagram of a specific charging system provided in an embodiment of the present application;

[0077] Figure 11 It is one of the switch states of the charging system provided in the embodiment of the present application;

[0078] Figure 12 This is the third step-down conversion state of the charging system provided in the embodiment of the present application;

[0079] Figure 13 This is the fourth step-down conversion state of the charging system provided in the embodiment of the present application;

[0080] Figure 14 This is the second switching state of the charging system provided in the embodiment of the present application;

[0081] Figure 15 This is a third switching state of the charging system provided in the embodiment of the present application;

[0082] Figure 16 This is one of the buck-boost conversion states of the charging system provided in the embodiment of the present application;

[0083] Figure 17 This is the second buck-boost conversion state of the charging system provided in the embodiment of the present application;

[0084] Figure 18 This is the third boost conversion state of the charging system provided in the embodiment of the present application;

[0085] Figure 19 This is the fourth boost conversion state of the charging system provided in the embodiment of the present application;

[0086] Figure 20 This is the third buck-boost conversion state of the charging system provided in the embodiment of the present application;

[0087] Figure 21 This is the fourth buck-boost conversion state of the charging system provided in the embodiment of the present application;

[0088] Figure 22 A schematic diagram of another charging system provided in an embodiment of the present application;

[0089] Figure 23 This is a fourth switching state of the charging system provided in the embodiment of the present application;

[0090] Figure 24 This is the fifth step-down conversion state of the charging system provided in the embodiment of the present application;

[0091] Figure 25 This is the sixth step-down conversion state of the charging system provided in the embodiment of the present application;

[0092] Figure 26 This is a fifth switching state of the charging system provided in an embodiment of the present application;

[0093] Figure 27 This is a sixth switching state of the charging system provided in the embodiment of the present application;

[0094] Figure 28 This is the fifth buck-boost conversion state of the charging system provided in the embodiment of the present application;

[0095] Figure 29 This is the sixth buck-boost conversion state of the charging system provided in the embodiment of the present application;

[0096] Figure 30 This is the fifth boost conversion state of the charging system provided in the embodiment of the present application;

[0097] Figure 31 This is the sixth boost conversion state of the charging system provided in the embodiment of the present application;

[0098] Figure 32 This is the seventh buck-boost conversion state of the charging system provided in the embodiment of the present application;

[0099] Figure 33 This is the eighth buck-boost conversion state of the charging system provided in the embodiment of the present application. DETAILED DESCRIPTION

[0100] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operating methods in the method embodiments can also be applied to device embodiments or system embodiments. It should be noted that in the description of the present application, "at least one" refers to one or more, wherein multiple refers to two or more. In view of this, "multiple" can also be understood as "at least two" in the embodiments of the present invention. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the previous and next associated objects are in an "or" relationship. In addition, it should be understood that in the description of the present application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0101] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0102] Electric vehicles, also known as new energy vehicles, are vehicles powered by electricity. Figure 1 As shown, electric vehicle 10 primarily includes a power battery 12, a motor 13, and wheels 14. The power battery 12 is a large-capacity, high-power storage battery. When electric vehicle 10 is in motion, the power battery 12 supplies power to the motor 13 via a motor control unit (MCU) 111. The motor 13 converts the electrical energy from the power battery 12 into mechanical energy, thereby driving the wheels 14 and enabling the vehicle to travel.

[0103] When the electric vehicle 10 is charged, the electric vehicle 10 can generally be charged through the charging pile 20. Figure 1As shown, the charging pile 20 mainly includes a power circuit 21 and a charging gun 22. One end of the power circuit 21 is connected to the power grid 30, and the other end is connected to the charging gun 22 via a cable. Currently, most charging piles 20 are DC charging piles. The power circuit 21 can convert the AC power provided by the power grid 30 into DC power. The operator can insert the charging gun 22 into the charging socket of the electric vehicle 10 to connect the charging gun 22 to the power battery 12 in the electric vehicle 10. The power circuit 21 of the charging pile 20 can then charge the power battery 12 through the charging gun 22.

[0104] The output voltage of the charging pile 20 can be understood as the power supply voltage received by the electric vehicle 10. In the DC fast charging scenario, the power supply voltage received by the electric vehicle 10 is within the charging voltage range of the power battery 12, and the power battery 12 can be directly charged using the output voltage of the charging pile 20.

[0105] The lower limit of the charging voltage range of the power battery 12 is the minimum charging voltage, which can be understood as the minimum charging voltage that the power battery 12 can adapt to. The upper limit of the charging voltage range of the power battery 12 is the maximum charging voltage, which can be understood as the maximum charging voltage that the power battery 12 can adapt to.

[0106] Currently, to increase the charging speed of electric vehicles 10, the voltage level of the power battery 12 is gradually increased from the current 500V to 800V. Taking an 800V power battery 12 as an example, the battery voltage of the power battery 12 can reach 800V, and the required charging voltage is often not less than 800V. However, for charging piles 20 currently on the market that support DC fast charging, their voltage level is generally 500V. In other words, the maximum output voltage of most charging piles 20 that support DC fast charging is 500V. This makes it difficult to charge many electric vehicles 10 equipped with high-voltage power batteries.

[0107] In view of this, an embodiment of the present application provides a charging system 11 connected to a power battery 12. When charging an electric vehicle 10, the charging system 11 can receive a power supply voltage. When the power supply voltage is less than the minimum charging voltage of the power battery 12, the charging system 11 can step up the power supply voltage and provide the stepped-up power supply voltage as a first output voltage to the power battery 12.

[0108] In the above example, the output voltage of the charging pile 20 is 500V, that is, the power supply voltage received by the charging system 11 is 500V. Assuming that the power battery 12 can adapt to a charging voltage of 960V, the charging system 11 can step up the power supply voltage to 960V, thereby providing a first output voltage of 960V for the power battery 12, so that the power battery 12 can complete charging using this first output voltage.

[0109] It should be noted that, in order to save space occupied by the charging system 11 in the electric vehicle 10 and control the cost of the charging system 11, the charging system 11 in the embodiment of the present application can be implemented based on the MCU 111 in the electric vehicle 10. The MCU 111 and the motor 13 are generally integrated into the electric drive system. In other words, the charging system 11 in the embodiment of the present application can be implemented by improving a conventional electric drive system.

[0110] Specifically, the motor 13 relies on the electromagnetic induction effect to realize the conversion of electrical energy into mechanical energy, so the motor 13 is provided with a motor winding. Currently, the number of motor windings in the motor 13 is mostly 3 or 6. Taking a three-phase motor as an example, Figure 2 As shown, the MCU 111 includes three bridge arms, the motor 13 includes three motor windings (N1 to N3), and the three bridge arms in the MCU 111 are connected to the three motor windings in the motor 13 in a one-to-one correspondence.

[0111] The first bridge arm includes a switch transistor T1 and a switch transistor T2. The first electrode of the switch transistor T1 is connected to the positive electrode of the power battery 12. The second electrode of the switch transistor T1 is connected to the first electrode of the switch transistor T2. The second electrode of the switch transistor T2 is connected to the negative electrode of the power battery 12. The midpoint of the first bridge arm, that is, the connection point between the switch transistors T1 and T2, is connected to one end of the motor winding N1.

[0112] The second bridge arm includes a switch transistor T3 and a switch transistor T4. The first electrode of the switch transistor T3 is connected to the positive electrode of the power battery 12. The second electrode of the switch transistor T3 is connected to the first electrode of the switch transistor T4. The second electrode of the switch transistor T4 is connected to the negative electrode of the power battery 12. The midpoint of the second bridge arm, that is, the connection point between the switch transistors T3 and T4, is connected to one end of the motor winding N2.

[0113] The third bridge arm includes switches T5 and T6. The first electrode of switch T6 is connected to the positive terminal of power battery 12. The second electrode of switch T3 is connected to the first electrode of switch T4, and the second electrode of switch T4 is connected to the negative terminal of power battery 12. The midpoint of the third bridge arm, that is, the connection point between switches T5 and T6, is connected to one end of motor winding N3, and the other ends of the three motor windings are connected.

[0114] The MCU 111 also includes a control board (not shown). This board is connected to the control electrodes of the switches T1 through T6, controlling the on and off of these switches. This allows the three bridge arms to convert the battery voltage output by the power battery 12 into three-phase AC power, with each bridge arm corresponding to one phase of the three-phase AC power. The MCU 111 outputs the three-phase AC power to the motor 13, causing the motor windings N1 through N3 to generate a spatially rotating magnetic field, thereby driving the motor rotor to rotate, thereby converting electrical energy into mechanical energy.

[0115] It should be noted that the switch tube in the embodiment of the present application may be one or more of various types of switch tubes such as a relay, a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), etc., and the embodiment of the present application will not list them one by one. Each switch tube may include a first electrode, a second electrode and a control electrode, wherein the control electrode is used to control the on or off of the switch tube. When the switch tube is turned on, current can be transmitted between the first electrode and the second electrode of the switch tube. When the switch tube is turned off, current cannot be transmitted between the first electrode and the second electrode of the switch tube. Taking IGBT as an example, in the embodiment of the present application, the first electrode of the switch tube may be a collector, the second electrode may be an emitter, and the control electrode may be a gate electrode.

[0116] Generally speaking, if Figure 2 As shown, switches K2 and K5 may be provided between the power battery 12 and the MCU 111. For example, switches K2 and K5 may be relays. Switches K2 and K5 may be integrated with the power battery 12 within the battery pack or independently provided, and this embodiment of the present application does not impose any particular limitation thereto.

[0117] One end of switch K2 is connected to the anode of the power battery 12, and the other end is connected to the high-potential ends of the three bridge arms. One end of switch K5 is connected to the cathode of the power battery 12, and the other end is connected to the low-potential ends of the three bridge arms. When switches K2 and K5 are turned on, the power battery 12 can power the MCU 111. When switches K2 and K5 are turned off, the power battery 12 stops powering the MCU 111.

[0118] As can be seen from the above description of the MCU 111 and the motor 13, the MCU 111 includes N bridge arms, where N is an integer greater than or equal to 1. It will be appreciated that when the electric vehicle 10 is charging, the electric vehicle 10 often does not need to move, meaning that the MCU 111 does not need to provide three-phase power to the motor 13. Therefore, the embodiments of the present application can charge the power battery 12 based on the N bridge arms in the MCU without affecting the driving function of the electric vehicle 10.

[0119] Next, the charging system 11 provided in the embodiment of the present application is further illustrated by the following examples.

[0120] Example 1

[0121] Exemplarily, the charging system 11 provided in the embodiment of the present application includes an MCU 111 and a motor 13. The MCU 111 includes N bridge arms, and the motor 13 includes N motor windings. The N bridge arms and the N motor windings are respectively connected in a one-to-one correspondence, where N is an integer greater than or equal to 1.

[0122] Take N=3 as an example, Figure 3 As shown, the charging system 11 includes an MCU 111 and a motor 13. The first battery terminal of the charging system 11 is connected to the positive electrode of the power battery 12, the second battery terminal is connected to the negative electrode of the power battery 12, the first power terminal of the charging system 11 is connected to the positive electrode of the DC power supply, and the second power terminal of the charging system is connected to the negative electrode of the DC power supply.

[0123] The DC power source can be a charging station, another electric vehicle, etc., and the embodiments of the present application do not impose any restrictions on this. The DC power source can output a power voltage. The charging system 11 receives the power voltage through the first power terminal and the second power terminal, converts the power voltage into a first output voltage adapted to the power battery 12, and outputs it to the power battery 12 through the first battery terminal and the second battery terminal. The power battery 12 can then receive the first output voltage provided by the charging system 11, thereby completing charging.

[0124] Specifically, if Figure 3As shown, MCU111 includes three bridge arms. In the embodiment of the present application, the high potential ends of the three bridge arms in MCU111 are connected to the first power supply terminal, and the low potential ends of the three bridge arms are connected to the second battery terminal of the charging system 11. The charging system 11 also includes an inductor L1, one end of the inductor L1 is connected to the second power supply terminal, and the other end of the inductor L2 is connected to the middle point of any bridge arm in MCU11. Figure 3 In the specific example shown, the other end of the inductor L2 is connected to the middle point of the bridge arm 2 where the switch tube T3 and the switch tube T4 are located.

[0125] In this case, the three bridge arms and inductor L1 in MCU111 can form a voltage conversion circuit, so that MCU111 can control the on and off of each switch tube among the switch tubes T1 to T6, so that the above voltage conversion circuit can realize the conversion of the power supply voltage.

[0126] Therefore, when the power supply voltage is lower than the minimum charging voltage of the power battery 12, the MCU111 can boost the power supply voltage through the voltage conversion circuit, and output the boosted power supply voltage as the first output voltage to the power battery, and the first output voltage is not lower than the minimum charging voltage of the power battery 12.

[0127] For example, the power supply voltage is 500 V and the minimum charging voltage of the power battery 12 is 960 V. The MCU 111 can boost the power supply voltage to 960 V or above, thereby providing an adaptive first output voltage for the power battery 12 so that the power battery 12 can be fully charged.

[0128] Generally speaking, if Figure 3 As shown, the charging system 11 also includes a switch K3 and a switch K4. Switches K3 and K4 can also be referred to as fast contactors. One end of switch K3 is connected to the connection point of motor windings N1 to N3, and the other end of switch K3 is connected to the second power supply terminal. One end of switch K4 is connected to the high-potential ends of the three bridge arms, and the other end of switch K4 is connected to the first power supply terminal. When switches K3 and K4 are turned on, the DC power supply can power the charging system 11. When switches K3 and K4 are turned off, the DC power supply can stop powering the charging system 11.

[0129] Next, the boost conversion process is further illustrated using bridge arm 2, which includes switches T3 and T4, as an example. The midpoint of bridge arm 2 is the connection point between switches T3 and T4. One end of inductor L1 is connected to the second power supply terminal, and the other end of inductor L1 is connected to the midpoint of bridge arm 2. The power supply voltage boost conversion primarily involves the following two stages:

[0130] Phase 1: Charging of inductor L1

[0131] MCU111 can turn on the switch tube T3 to charge the inductor L1. It can be understood that the switch tube T4 is turned off at this time. Figure 4 As shown, the current is output from the positive electrode of the DC power supply, transmitted through the switch tube T3 and the inductor L1, and then flows back to the negative electrode of the DC power supply, thereby forming a charging circuit to charge the inductor L1.

[0132] Phase 2: Inductor L1 discharges

[0133] MCU111 can turn off the switch tube T3, and the inductor L1 can no longer receive current through the switch tube T3. Due to the freewheeling characteristics of the inductor, the inductor L1 begins to discharge. Figure 5 As shown, current is output from the end of inductor L1 closest to the second power supply terminal, transmitted through the DC power supply, power battery 12, and the diode in switch T4, and then returns to the end of inductor L1 closest to switch T4. During this process, the first output voltage of charging system 11 is the sum of the DC power supply voltage and the voltage across inductor L1. Clearly, this first output voltage is greater than the DC power supply voltage, thus achieving a step-up conversion.

[0134] It is understood that when the power of the DC power supply is large, the MCU 111 can also synchronously control multiple bridge arms to perform boost conversion. For example, Figure 6 As shown, MCU 111 includes three inductors (inductors L1-1 to L1-3) and three switches K3 (switches K3-1 to K3-3). One end of switches K3-1 to K3-3 is connected to the second power supply terminal, and the other ends of switches K3-1 to K3-3 are connected to one end of the three inductors (inductors L1-1 to L1-3) in a one-to-one correspondence. Specifically, switch K3-1 is connected to one end of inductor L1-1, switch K3-2 is connected to one end of inductor L1-2, and switch K3-3 is connected to one end of inductor L1-3.

[0135] The three inductors are connected to the midpoints of the three bridge arms in the MCU 111 in a one-to-one correspondence. One end of the inductor L1-1 is connected to the second power supply terminal of the charging system 11, and the other end of the inductor L1-1 is connected to the midpoint between the switch transistors T1 and T2. One end of the inductor L1-2 is connected to the second power supply terminal of the charging system 11, and the other end of the inductor L1-2 is connected to the midpoint between the switch transistors T3 and T4. One end of the inductor L1-3 is connected to the second power supply terminal of the charging system 11, and the other end of the inductor L1-3 is connected to the midpoint between the switch transistors T5 and T6.

[0136] When charging the power battery 12, the MCU 111 can turn on switches K3-1 through K3-3. The MCU 111 can synchronously control the on and off of switches T1, T3, and T5, allowing the inductors L1-1 through L1-3 to charge and discharge synchronously. In this case, the three inductors operate in parallel, thus supporting voltage conversion in high-power scenarios. After stopping charging the power battery 12, the MCU 111 can turn off switches K3-1 through K3-3. In this case, the circuit between inductors L1-1 through L1-3 is disconnected, reducing the impact of inductors L1-1 through L1-3 on the MCU 111's inverter process.

[0137] In summary, the charging system 11 in the embodiment of the present application can boost the power voltage of the DC power supply, thereby charging the high-voltage power battery 12, which is conducive to improving the convenience of charging the high-voltage power battery 12. At the same time, the embodiment of the present application implements the charging system 11 by reusing the N bridge arms in the MCU 111, which is also conducive to reducing the space and cost occupied by the charging system 11.

[0138] It is understood that the power voltage provided by the DC power supply may also be adapted to the power battery 12. For example, the charging voltage range of the power battery 12 is 700-1000V, and the power voltage of the DC power supply (charging pile) is 800V. In this case, there is no need to perform a step-up conversion on the power voltage.

[0139] To be compatible with this scenario, Figure 7 As shown, the charging system 11 provided in this embodiment of the present application may further include a switch K1. A first end of the switch K1 is connected to the second battery terminal, and a second end of the switch K1 is connected to the second power supply terminal. The MCU 111 can control the on and off of the switch K1. Specifically, the MCU 111 can turn on the switch K1 when the power supply voltage is within the charging voltage range of the power battery 12, and turn off the switch K1 when the power supply voltage is outside the charging voltage range of the power battery 12.

[0140] The scenario where the power supply voltage is within the charging voltage range of the power battery 12 may be a scenario where the power supply voltage is equal to the minimum charging voltage of the power battery 12, a scenario where the power supply voltage is equal to the maximum charging voltage of the power battery 12, or a scenario where the power supply voltage is greater than the minimum charging voltage of the power battery 12 but less than the maximum charging voltage of the power battery 12. The scenario where the power supply voltage is outside the charging voltage range of the power battery 12 may be a scenario where the power supply voltage is less than the minimum charging voltage of the power battery 12, or a scenario where the power supply voltage is greater than the maximum charging voltage of the power battery 12.

[0141] like Figure 7As shown, when the power battery 12 is charging, switch K5 is turned on by default. When switch K1 is turned on, the power battery 12 can be directly connected to the DC power supply and can directly receive the power supply voltage provided by the DC power supply to complete charging. Therefore, the MCU 111 can turn on switch K1 when the power supply voltage is within the charging voltage range of the power battery 12.

[0142] When switch K1 is turned off, Figure 7 The charging system 11 shown is equivalent to Figure 3 In the charging system 11 shown, the MCU 111 can perform a voltage boost conversion on the power supply voltage, which will not be described in detail.

[0143] In one possible implementation, Figure 3 As shown, the charging system 11 may further include a filter capacitor C1, one end of the filter capacitor C1 being connected to the first battery terminal, and the other end of the filter capacitor C1 being connected to the second battery terminal. When charging the power battery 12, the filter capacitor C1 may filter the first output voltage.

[0144] Similar, such as Figure 3 As shown, the charging system 11 may further include a filter capacitor C2, one end of which is connected to the first power supply terminal, and the other end of which is connected to the second power supply terminal. When charging the power battery 12, the filter capacitor C2 may filter the received power supply voltage.

[0145] Example 2

[0146] With the development of charging and discharging technology of electric vehicles 10, more and more electric vehicles 10 can also support discharge function, that is, electric vehicles 10 supply power to DC loads. In some scenarios, the DC load can be another electric vehicle. For example, Figure 3 As shown, the first power supply terminal of the charging system 11 can also be connected to the positive pole of the DC load, and the second power supply terminal of the charging system 11 can also be connected to the negative pole of the DC load.

[0147] The power battery 12 can output a battery voltage to the charging system 11. When the battery voltage of the power battery 12 is greater than the maximum operating voltage of the DC load, the charging system 11 can step down the battery voltage to obtain a second output voltage compatible with the DC load, and then output the second output voltage to the DC load via the first and second power supply terminals. If the DC load is another electric vehicle, the operating voltage range of the DC load can be understood as the charging voltage range of the power battery in the other electric vehicle.

[0148] The lower limit of the DC load's operating voltage range is the minimum operating voltage, which can be understood as the minimum operating voltage that the DC load can adapt to. The upper limit of the DC load's operating voltage range is the maximum operating voltage, which can be understood as the maximum operating voltage that the DC load can adapt to.

[0149] For example, if the battery voltage of power battery 12 is 800V and the operating voltage range of the DC load is 400-600V, MCU 111 can step down the battery voltage to obtain a second output voltage within the operating voltage range. Charging system 11 outputs the second output voltage to the DC load, thereby providing an appropriate operating voltage for the DC load.

[0150] Next, Figure 3 Taking the bridge arm 2 including the switch tubes T3 and T4 as an example, the step-up conversion process is further illustrated. It is understood that at this time, switches K2 to K5 are turned on, and this will not be described in detail. When the battery voltage is stepped down, it mainly includes the following two stages:

[0151] Phase 1: Charging of inductor L1

[0152] MCU111 turns on the switch tube T4, while the switch tube T3 remains off. Figure 8 As shown, current is output from the positive electrode of power battery 12, transmitted through the DC load, inductor L1, and switch T4, and then flows back to the negative electrode of power battery 12. During this phase, inductor L1 is charged. The second output voltage of charging system 11 is the difference between the battery voltage and the voltage of inductor L1. Obviously, the second output voltage is lower than the battery voltage, so charging system 11 can achieve step-down conversion of the battery voltage.

[0153] Phase 2: Inductor L1 discharges

[0154] MCU111 can turn off the switch tube T4, and the charging circuit of the inductor L1 is cut off. Due to the freewheeling characteristics of the inductor, the inductor L1 begins to discharge. Figure 9 As shown, current is output from the end of inductor L1 near switch T3, transmitted through the diode in switch T3 and the DC load, and then flows back to the end of inductor L1 near the second power supply terminal. During this process, the second output voltage of charging system 11 is the voltage of inductor L1. Obviously, the voltage of inductor L1 is lower than the battery voltage, so charging system 11 can achieve step-down conversion of the battery voltage.

[0155] Understandably, Figure 6In the illustrated charging system 11, the MCU 111 can also synchronously control multiple bridge arms to perform boost conversion. For example, the MCU 111 can synchronously control the on and off of switches T2, T4, and T6 to synchronously charge and discharge inductors L1-1 through L1-3. In this case, the three inductors operate in parallel, thus supporting voltage conversion in high-power scenarios.

[0156] It should be pointed out that if Figure 7 The illustrated charging system 11 is also suitable for stepping down the battery voltage. When the battery voltage is within the operating voltage range of the DC load, the MCU 111 can turn on switch K1, allowing the power battery 12 to directly power the DC load. When the battery voltage is outside the operating voltage range of the DC load, the MCU 111 can turn off switch K1, allowing the MCU 111 to perform voltage conversion on the battery voltage. Details are omitted here.

[0157] The scenario where the battery voltage is within the operating voltage range of the DC load can be either the scenario where the battery voltage is equal to the minimum operating voltage of the DC load, the scenario where the battery voltage is equal to the maximum operating voltage of the DC load, or the scenario where the battery voltage is greater than the minimum operating voltage of the DC load but less than the maximum operating voltage of the DC load. The scenario where the battery voltage is outside the operating voltage range of the DC load can be either the scenario where the battery voltage is less than the minimum operating voltage of the DC load, or the scenario where the battery voltage is greater than the maximum operating voltage of the DC load.

[0158] Example 3

[0159] As mentioned above, there are both low-voltage and high-voltage charging piles in the current market. Electric vehicles 10 can be equipped with both high-voltage and low-voltage power batteries. Therefore, it will be common to use high-voltage charging piles to charge low-voltage power batteries.

[0160] In view of this, the present embodiment further provides a charging system 11. The connection relationship between the charging system 11, the DC power supply, and the power battery 12 is the same as in the above embodiment and will not be further described. When the DC power supply voltage is greater than the maximum charging voltage of the power battery 12, the charging system 11 can step down the power supply voltage. When the DC power supply voltage is less than the minimum charging voltage of the power battery 12, the charging system 11 can step up the power supply voltage. Therefore, the charging system 11 can provide the power battery 12 with a first output voltage that is compatible with it.

[0161] For example, Figure 10As shown, the charging system 11 in the embodiment of the present application may include an MCU 111 and an inductor L1. The connection relationship between the N bridge arms in the MCU 111 and the inductor L1 is not further described. In addition, the charging system 11 may also include a switch K1 and a switch K2. The first end of the switch K1 is connected to the second battery terminal of the charging system 11, and the second end of the switch K1 is connected to the second power supply terminal. The switch K2 is a single-pole double-throw switch, wherein the first end of the switch K2 is connected to the first battery terminal, the second end a of the switch K2 is connected to one end of the inductor L1, and the third end b of the switch K2 is connected to the first power supply terminal.

[0162] It should be noted that the switch K2 can be provided independently of the power battery 12. In this case, the first terminal of the switch K2 can be understood as the first battery terminal of the charging system 11. It is understood that the switch K2 can also be integrated with the power battery 12 within the power battery pack. In this case, the charging system 11 provided in this embodiment of the application can be considered to include two first battery terminals, one of which is connected to the second terminal a of the switch K2, and the other first battery terminal is connected to the third terminal b of the switch K2.

[0163] Next, Figure 10 As an example, the step-down conversion and step-up conversion of the power supply voltage are respectively explained.

[0164] 1. Buck Conversion

[0165] During the step-down conversion process, the MCU 111 can turn on the switch K1 and the first and second terminals a of the switch K2. The circuit state can be as follows: Figure 11 It should be noted that in some scenarios, switches K3 to K5 may also be provided in the charging system 11. In this case, switches K4 and K5 should be kept turned on, and switch K3 should be kept turned off. Figure 11 In the circuit state shown, taking the bridge arm 2 including the switch tube T3 and the switch tube T4 as an example, the step-down conversion process mainly includes:

[0166] Phase 1: Charging of inductor L1

[0167] MCU111 turns on the switch tube T3 to charge the inductor L1. Figure 12 As shown, current is output from the positive terminal of the DC power supply, transmitted through switch T3, inductor L1, switch K2, and power battery 12, and then flows back to the negative terminal of the DC power supply, thus forming a charging circuit and charging inductor L1. During this process, the first output voltage of charging system 11 is the difference between the power supply voltage and the voltage across inductor L1. Obviously, the first output voltage is lower than the power supply voltage, so charging system 11 can achieve step-down conversion.

[0168] Phase 2: Inductor L1 discharges

[0169] MCU111 turns off the switch tube T3 to discharge the inductor L1. Specifically, after MCU111 turns off the switch tube T3, the charging circuit is turned off. Due to the freewheeling characteristics of the inductor, the inductor L1 discharges. Figure 13 As shown, current is output from the end of inductor L1 closest to the second power supply terminal, transmitted through switch K2, power battery 12, and the diode in switch tube T4, and then returns to the end of inductor L1 closest to switch tube T4. During this process, the first output voltage of charging system 11 is the voltage of inductor L1. Obviously, this first output voltage is lower than the power supply voltage, so charging system 11 can achieve step-down conversion of the power supply voltage.

[0170] 2. Boost Conversion

[0171] like Figure 10 As shown, the charging system 11 may further include a switch K3. The first end of the switch K3 is connected to the connection point of the motor windings N1 to N3, and the second end of the switch K3 is connected to the second power supply terminal. During the boost conversion process, the MCU 111 can turn on the first end and the third end b of the switch K2, turn on the switch K3, and turn off the switch K1. The circuit state can be as follows: Figure 14 As shown. Figure 14 It can be seen that the circuit state in this case is equivalent to Figure 3 The charging system 11 shown in the figure can therefore refer to the boost conversion process provided in the above embodiment 1, which will not be described in detail.

[0172] also, Figure 10 The charging system 11 shown can also support a buck-boost mode voltage conversion of the power supply voltage.

[0173] Specifically:

[0174] Buck-Boost

[0175] When performing buck-boost conversion on the power supply voltage, the MCU 111 can turn on the first terminal and the second terminal a of the switch K2, and turn on the switch K3. The circuit state can be as follows: Figure 15 Based on Figure 15 As shown in the circuit state, the buck-boost conversion mainly includes the following two stages:

[0176] Phase 1: Charging of inductor L1

[0177] MCU111 turns on the switch tube T3 to charge the inductor L1. Figure 16 As shown, the current is output from the positive electrode of the DC power supply, transmitted through the switch tube T3 and the inductor L1, and then flows back to the negative electrode of the DC power supply, thereby forming a charging circuit for the inductor L1 to charge the inductor L1.

[0178] Phase 2: Inductor L1 discharges

[0179] MCU111 turns off the switch tube T3 to discharge the inductor L1. Figure 17 As shown, current is output from the end of inductor L1 closest to the second power supply terminal, transmitted through switch K2, power battery 12, and the diode in switch tube T4, and then flows back to the end of inductor L1 closest to switch tube T4. As can be seen, the first output voltage of charging system 11 is equal to the voltage of inductor L1. By controlling the charging time of inductor L1 in stage 1, MCU 111 can control the voltage of inductor L1, thereby controlling the magnitude of the first output voltage. This first output voltage can be greater than or less than the power supply voltage.

[0180] Similar to the first embodiment, when the DC power supply voltage is within the charging voltage range of the power battery 12, the MCU 111 can also turn on the first terminal and the third terminal b of the switch K2, and turn on the switch K1, so that the power battery 12 can directly receive the power supply voltage, thereby completing charging. The specific implementation can be referred to in the first embodiment and will not be described in detail here.

[0181] Example 4

[0182] It should be pointed out that Figure 10 The charging system 11 shown can also support the discharge function of the electric vehicle 10. When the electric vehicle 10 is discharging, the connection relationship between the charging system 11, the power battery 12 and the DC load is similar to that in the second embodiment, and will not be repeated here.

[0183] The difference from the second embodiment is that: Figure 10 The provided charging system 11 can not only step down the battery voltage but also step up the battery voltage so that the battery voltage output by the high-voltage power battery and the low-voltage power battery can adapt to DC loads with different operating voltage ranges.

[0184] Next, Figure 10 As an example, the boost conversion and buck conversion of the battery voltage are respectively explained.

[0185] 1. Boost Conversion

[0186] During the boost conversion process, the MCU 111 can turn on the switch K1 and the first and second terminals a of the switch K2. The circuit state can be as follows: Figure 11 Based on Figure 11 In the circuit state shown, taking the bridge arm 2 including the switch tube T3 and the switch tube T4 as an example, the boost conversion process mainly includes:

[0187] Phase 1: Charging of inductor L1

[0188] MCU111 turns on the switch tube T4 to charge the inductor L1. Figure 18 As shown, the current is output from the positive electrode of the power battery 12, transmitted through the switch K2, the inductor L1 and the switch tube T4, and then flows back to the negative electrode of the power battery 12, thereby forming a charging circuit to charge the inductor L1.

[0189] Phase 2: Inductor L1 discharges

[0190] MCU111 turns off the switch tube T4 to discharge the inductor L1. After MCU111 turns off the switch tube T4, the charging circuit is cut off. Due to the freewheeling characteristics of the inductor, the inductor L1 discharges. Figure 19 As shown, current is output from the positive electrode of the power battery 12, transmitted through the switch K2, the inductor L1, the diode in the switch tube T3, and the DC load, and then flows back to the negative electrode of the power battery 12. During this process, the second output voltage of the charging system 11 is the sum of the battery voltage of the power battery 12 and the voltage of the inductor L1. Obviously, the second output voltage is greater than the battery voltage, so the charging system 11 can achieve a step-up conversion of the battery voltage.

[0191] 2. Buck Conversion

[0192] like Figure 10 As shown, the charging system 11 may further include a switch K3. The first end of the switch K3 is connected to the connection point of the motor windings N1 to N3, and the second end of the switch K3 is connected to the second power supply terminal. During the step-down conversion process, the MCU 111 may turn on the first end and the third end b of the switch K2, turn on the switch K3, and turn off the switch K1. The circuit state may be as follows: Figure 14 As shown. Figure 14 It can be seen that the circuit state in this case is equivalent to Figure 3 The charging system 11 shown can therefore refer to the step-down conversion process provided in the above-mentioned embodiment 2, which will not be described in detail.

[0193] also, Figure 10 The charging system 11 shown can also support buck-boost mode voltage conversion of the battery voltage. Specifically:

[0194] Buck-Boost

[0195] When performing buck-boost conversion on the battery voltage, the MCU 111 can turn on the first terminal and the second terminal a of the switch K2, and turn on the switch K3. The circuit state can be as follows: Figure 15 Based on Figure 15 As shown in the circuit state, the buck-boost conversion mainly includes the following two stages:

[0196] Phase 1: Charging of inductor L1

[0197] MCU111 turns on the switch tube T4 to charge the inductor L1. Figure 20 As shown, the current is output from the positive electrode of the power battery 12, transmitted through the switch K2, the inductor L1 and the switch tube T4, and then flows back to the negative electrode of the power battery 12, thereby forming a charging circuit for the inductor L1.

[0198] Phase 2: Inductor L1 discharges

[0199] MCU111 turns off the switch tube T4 to discharge the inductor L1. Figure 21 As shown, current is output from the end of inductor L1 near switch T3, transmitted through the diode in switch T3 and the DC load, and then returns to the end of inductor L1 near the second power supply terminal. Therefore, the second output voltage of charging system 11 is equal to the voltage of inductor L1. By controlling the charging time of inductor L1 in stage 1, MCU 111 can control the voltage of inductor L1, thereby controlling the magnitude of the second output voltage. This second output voltage can be greater than or less than the battery voltage.

[0200] Similar to Example 2, when the battery voltage of the power battery 12 is within the operating voltage range of the DC load, the MCU 111 can also turn on the first terminal and the third terminal b of the switch K2, and turn on the switch K1, so that the power battery 12 can directly power the DC load. The specific implementation can be referred to Example 2 and will not be described in detail here.

[0201] Example 5

[0202] In the third and fourth embodiments, the inductor L1 is connected to the second power supply terminal. Based on a similar concept, the inductor L1 can also be connected to the first power supply terminal. In this case, the charging system 11 can be as follows: Figure 22 shown.

[0203] The charging system 11 further includes a switch K5 and a switch K6. The switch K5 is a single-pole double-throw switch, wherein a first terminal of the switch K5 is connected to the second battery terminal, a second terminal a of the switch K5 is connected to the low-potential terminals of the N bridge arms, a third terminal b of the switch K5 is connected to one terminal of the inductor L1, a second terminal of the switch K6 is connected to the second power terminal, a first terminal of the switch K6 is connected to the first battery terminal, and a second terminal of the switch K6 is connected to the first power terminal.

[0204] It should be noted that the switch K5 can be provided independently of the power battery 12. In this case, the first terminal of the switch K5 can be understood as the second battery terminal of the charging system 11. It is understood that the switch K5 can also be integrated with the power battery 12 within the power battery pack. In this case, the charging system 11 provided in this embodiment of the application can be considered to include two second battery terminals, one of which is connected to the second terminal a of the switch K5, and the other second battery terminal is connected to the third terminal b of the switch K5.

[0205] Next, Figure 22 As an example, the step-down conversion and step-up conversion of the power supply voltage are respectively explained.

[0206] 1. Buck Conversion

[0207] When the power supply voltage is greater than the maximum charging voltage, the MCU111 can step down the power supply voltage. During the step-down conversion process, the MCU111 can turn on the switch K6, and the first and third terminals b of the switch K5. The circuit state can be as follows: Figure 23 It should be noted that in some scenarios, switches K2 to K4 may also be provided in the charging system 11. In this case, switches K2 and K3 should be kept turned on, and switch K4 should be kept turned off. Figure 23 In the circuit state shown, taking the bridge arm 2 including the switch tube T3 and the switch tube T4 as an example, the step-down conversion process mainly includes:

[0208] Phase 1: Charging of inductor L1

[0209] MCU111 turns on the switch tube T4 to charge the inductor L1. Figure 24 As shown, current is output from the positive electrode of the DC power supply, transmitted through the power battery 12, switch K5, inductor L1, and switch T4, and then flows back to the negative electrode of the DC power supply, thus forming a charging circuit and charging inductor L1. During this process, the first output voltage of the charging system 11 is the difference between the power supply voltage and the voltage of the inductor L1. Obviously, the first output voltage is lower than the power supply voltage, so the charging system 11 can achieve step-down conversion.

[0210] Phase 2: Inductor L1 discharges

[0211] MCU111 turns off the switch tube T4 to discharge the inductor L1. Turn off the second switch tube to discharge the inductor L1. Specifically, after MCU111 turns off the switch tube T4, the charging circuit is turned off. Due to the freewheeling characteristics of the inductor, the inductor L1 discharges. Figure 25As shown, current is output from the end of inductor L1 near switch T3, transmitted through the diode in switch T3, power battery 12, and switch K5, and then returns to the end of inductor L1 near the first power supply terminal. During this process, the first output voltage of charging system 11 is the voltage of inductor L1. Obviously, this first output voltage is lower than the power supply voltage, so charging system 11 can achieve step-down conversion of the power supply voltage.

[0212] 2. Boost Conversion

[0213] like Figure 22 As shown, the charging system 11 may further include a switch K4. The first end of the switch K4 is connected to the connection end of the N motor windings, and the second end of the switch K4 is connected to the first power supply end. During the boost conversion process, the MCU 111 may conduct the first end and the second end a of the switch K5, conduct the switch K4 and turn off the switch K6, and the circuit state may be as follows: Figure 26 As shown. Figure 26 It can be seen that the circuit state in this case is equivalent to Figure 3 The charging system 11 shown in the figure can therefore refer to the boost conversion process provided in the above embodiment 1, which will not be described in detail.

[0214] also, Figure 22 The charging system 11 shown can also support a buck-boost mode voltage conversion for the power supply voltage.

[0215] Specifically:

[0216] Buck-Boost

[0217] When performing buck-boost conversion on the power supply voltage, the MCU 111 can turn on the first terminal and the third terminal b of the switch K5, and turn on the switch K4. The circuit state can be as follows: Figure 27 Based on Figure 27 As shown in the circuit state, the buck-boost conversion mainly includes the following two stages:

[0218] Phase 1: Charging of inductor L1

[0219] MCU111 turns on the switch tube T4 to charge the inductor L1. Figure 28 As shown, the current is output from the positive electrode of the DC power supply, transmitted through the switch tube inductor L1 and the switch tube T4, and then flows back to the negative electrode of the DC power supply, thereby forming a charging circuit for the inductor L1.

[0220] Phase 2: Inductor L1 discharges

[0221] MCU111 turns off the switch tube T3 to discharge the inductor L1. Figure 29As shown, current is output from the end of inductor L1 near switch T3, transmitted through the diode in switch T3, power battery 12, and switch K5, and then returns to the end of inductor L1 near the first power supply terminal. Thus, the first output voltage of charging system 11 is equal to the voltage of inductor L1. By controlling the charging time of inductor L1 in stage 1, MCU 111 can control the voltage of inductor L1, thereby controlling the magnitude of the first output voltage. This first output voltage can be greater than or less than the power supply voltage.

[0222] Similar to the first embodiment, when the DC power supply voltage is within the charging voltage range of the power battery 12, the MCU 111 may also turn on the first and second terminals a of the switch K5, and also turn on the switch K6, so that the power battery 12 can directly receive the power supply voltage, thereby completing charging. For a specific implementation, please refer to the first embodiment and will not be described in detail here.

[0223] Example 6

[0224] It should be pointed out that Figure 22 The charging system 11 shown can also not only step down the battery voltage but also step up the battery voltage so that the battery voltages output by the high-voltage power battery and the low-voltage power battery can adapt to DC loads with different operating voltage ranges.

[0225] Next, Figure 22 As an example, the boost conversion and buck conversion of the battery voltage are respectively explained.

[0226] 1. Boost Conversion

[0227] During the boost conversion process, the MCU 111 can turn on the switch K6 and the first and third terminals b of the switch K5. The circuit state can be as follows: Figure 23 Based on Figure 23 In the circuit state shown, taking the bridge arm 2 including the switch tube T3 and the switch tube T4 as an example, the boost conversion process mainly includes:

[0228] Phase 1: Charging of inductor L1

[0229] MCU111 turns on the switch tube T3 to charge the inductor L1. Figure 30 As shown, the current is output from the positive electrode of the power battery 12, transmitted through the switch tube T3, the inductor L1 and the switch K5, and then flows back to the negative electrode of the power battery 12, thereby forming a charging circuit to charge the inductor L1.

[0230] Phase 2: Inductor L1 discharges

[0231] MCU111 turns off the switch tube T3 to discharge the inductor L1. After MCU111 turns off the switch tube T3, the charging circuit is cut off. Due to the freewheeling characteristics of the inductor, the inductor L1 discharges. Figure 32 As shown, current is output from the positive electrode of the power battery 12, transmitted through the DC load, the diode in the switch tube T4, the inductor L1, and the switch tube K5, and then flows back to the negative electrode of the power battery 12. During this process, the second output voltage of the charging system 11 is the sum of the battery voltage of the power battery 12 and the voltage of the inductor L1. Obviously, the second output voltage is greater than the battery voltage, so the charging system 11 can achieve a step-up conversion of the battery voltage.

[0232] 2. Buck Conversion

[0233] like Figure 22 The charging system 11 may further include a switch K4. The first end of the switch K4 is connected to the connection point of the N motor windings, and the second end of the switch K4 is connected to the first power supply terminal. During the step-down conversion process, the MCU 111 may conduct the first end and the second end a of the switch K5, conduct the switch K4, and turn off the switch K6. The circuit state may be as follows: Figure 26 As shown. Figure 26 It can be seen that the circuit state in this case is equivalent to Figure 3 The charging system 11 shown can therefore refer to the step-down conversion process provided in the above-mentioned embodiment 2, which will not be described in detail.

[0234] also, Figure 22 The charging system 11 shown can also support buck-boost mode voltage conversion of the battery voltage. Specifically:

[0235] Buck-Boost

[0236] When performing buck-boost conversion on the battery voltage, the MCU 111 can turn on the first terminal and the third terminal b of the switch K5, and turn on the switch K4. The circuit state can be as follows: Figure 27 Based on Figure 27 As shown in the circuit state, the buck-boost conversion mainly includes the following two stages:

[0237] Phase 1: Charging of inductor L1

[0238] MCU111 turns on the switch tube T3 to charge the inductor L1. Figure 32 As shown, the current is output from the positive electrode of the power battery 12, transmitted through the switch tube T3, the inductor L1 and the switch K5, and then flows back to the negative electrode of the power battery 12, thereby forming a charging circuit for the inductor L1.

[0239] Phase 2: Inductor L1 discharges

[0240] MCU111 turns off the switch tube T3 to discharge the inductor L1. Figure 33 As shown, current is output from the end of inductor L1 closest to the first power supply terminal, transmitted through the DC load and the diode in switch T4, and then returns to the end of inductor L1 closest to switch T4. Therefore, the second output voltage of charging system 11 is equal to the voltage of inductor L1. By controlling the charging time of inductor L1 in stage 1, MCU 111 can control the voltage of inductor L1, thereby controlling the magnitude of the second output voltage. This second output voltage can be greater than or less than the battery voltage.

[0241] Similar to Example 2, when the battery voltage of the power battery 12 is within the operating voltage range of the DC load, the MCU 111 can also turn on the first and second terminals a of the switch K5, and also turn on the switch K6, so that the power battery 12 can directly power the DC load. For a specific implementation, please refer to Example 2 and will not be described in detail here.

[0242] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A charging system, characterized in that: The charging system includes a motor controller, three inductors, and a third switch. The motor controller includes three bridge arms. The charging system is used to step up or step down the power supply voltage output by the DC power supply to charge the power battery, wherein: One end of each of the three bridge arms is used to connect to the positive electrode of the DC power supply and to connect to the positive electrode of the power battery, and the other end of each of the three bridge arms is used to connect to the negative electrode of the DC power supply and to connect to the negative electrode of the power battery; One end of each of the three inductors is used to connect to the midpoint of one of the three bridge arms, and the other end of each of the three inductors is used to connect to one of the positive electrode or the negative electrode of the DC power supply through the third switch; The three bridge arms, the three inductors and the third switch constitute a voltage conversion circuit, and the voltage conversion circuit is used for step-up conversion or step-down conversion of the power supply voltage output by the DC power supply.

2. The charging system according to claim 1, characterized in that The charging system further includes a first switch, which is used to connect or disconnect the connection between the other end of each of the three bridge arms and the negative electrode of the DC power supply.

3. The charging system according to claim 1 or 2, characterized in that: The charging system further includes a second switch, which is used to connect or disconnect the one end of each of the three bridge arms from the positive electrode of the power battery.

4. The charging system according to claim 3, wherein: The second switch is a single-pole double-throw switch, and the second switch is also used to connect or disconnect the positive electrode of the power battery and the negative electrode of the DC power supply.

5. The charging system according to any one of claims 1 to 4, characterized in that: The charging system further includes a fourth switch, which is used to connect or disconnect the one end of each of the three bridge arms from the positive electrode of the DC power supply.

6. The charging system according to any one of claims 1 to 5, characterized in that: The charging system further includes a fifth switch, which is used to connect or disconnect the other end of each of the three bridge arms from the negative electrode of the power battery.

7. The charging system according to claim 6, characterized in that The fifth switch is a single-pole double-throw switch, and the second switch is also used to connect or disconnect the negative electrode of the power battery and the positive electrode of the DC power supply.

8. The charging system according to any one of claims 1 to 7, characterized in that: The charging system further includes a filter capacitor, and two ends of the filter capacitor are respectively used to connect the positive electrode and the negative electrode of the DC power supply.

9. The charging system according to any one of claims 1 to 8, characterized in that: The motor controller is configured to selectively perform step-up conversion or step-down conversion on the voltage of the DC power supply according to the relationship between the voltage of the DC power supply and the charging voltage of the power battery when the power supply voltage is outside the charging voltage range of the power battery; The motor controller is specifically used for: When the DC power supply voltage is lower than the minimum charging voltage of the power battery, the voltage conversion circuit performs a voltage boost conversion on the DC power supply voltage superimposed on the voltages of the three inductors, and outputs the boosted voltage as the first output voltage to the power battery; When the power supply voltage is greater than the maximum charging voltage of the power battery, the power supply voltage is stepped down by the voltage conversion circuit, and the stepped-down power supply voltage is output to the power battery as the first output voltage.

10. The charging system according to claim 6, characterized in that: The motor controller is also used to: During the process of the voltage conversion circuit performing a step-up conversion on the power supply voltage, the first switch is turned off, the third switch and the fifth switch are turned on, and the second switch is controlled to connect the one end of each of the three bridge arms to the positive electrode of the power battery.

11. The charging system according to claim 6, wherein: The motor controller is also used to: During the process of the voltage conversion circuit performing step-down conversion on the power supply voltage, the first switch is turned off, the third switch and the fifth switch are turned on, and the second switch is controlled to conduct the connection between the positive electrode of the power battery and the negative electrode of the DC power supply.

12. The charging system according to claim 6, wherein: The motor controller is also used to: When the power supply voltage is within the charging voltage range of the power battery, the first switch, the second switch and the fifth switch are turned on and the third switch is turned off, so that the DC power supply directly supplies power to the power battery.

13. The charging system according to claim 10, wherein: During the process of the voltage conversion circuit performing a step-up conversion on the DC power supply voltage, the motor controller is specifically configured to: Turning on the upper bridge arm switch tube of each bridge arm of the three bridge arms, so that the DC power supply charges the three inductors; The first switch tube is turned off, so that the DC power supply and the three inductors charge the power battery together.

14. The charging system according to claim 11, wherein: During the process of the voltage conversion circuit performing step-down conversion on the DC power supply voltage, the motor controller is specifically configured to: Turning on the upper bridge arm switch tube of each of the three bridge arms to enable the DC power supply to charge the three inductors and the power battery; The first switch tube is turned off to allow the three inductors to charge the power battery.

15. An electric vehicle, characterized in that: The device comprises a power battery and a charging system according to any one of claims 1 to 14, wherein the charging system is used to charge the power battery.

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