Current detection circuit, motor drive device and electric vehicle

Abstract

The present application discloses a current detection circuit, a motor drive device and an electric vehicle, wherein the current detection circuit includes a microcontroller, a power supply circuit and M sensor groups, each of the M sensor groups includes N sensors; the sensors are respectively connected to the microcontroller and the power supply circuit; the power supply circuit supplies power to the sensors; the M sensor groups respectively detect the output current of the M phase output in the K phase output included in the inverter, and the N sensors included in each sensor group respectively detect the output current of the corresponding phase output in the M phase output; the microcontroller determines the target output current of the K phase output of the inverter according to the output current detected by the M sensor groups. In the embodiment of the present application, the final output current of the output of one phase is determined by detecting multiple output currents of the output of one phase. Since different output currents of the same phase output detected can be verified with each other, the current output by the inverter to the motor can be accurately detected by the sensor.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a current detection circuit, a motor drive device and an electric vehicle. Background Art

[0002] With the continuous development of electronic technology, users have higher and higher requirements for the performance of electronic equipment. The motor is an important component in electronic equipment, so the stability of the motor is very important. In order to ensure the stability of the motor, it is necessary to detect the current output to the motor by the inverter in the motor drive device. How to accurately detect the current output to the motor by the inverter has become a problem that needs to be solved urgently. Utility Model Content

[0003] The embodiments of the present application disclose a current detection circuit, a motor drive device and an electric vehicle, which are used to accurately detect the current output by an inverter to a motor through a sensor.

[0004] In a first aspect, an embodiment of the present application discloses a current detection circuit, including a microcontroller, a power supply circuit, and M sensor groups, each of the M sensor groups includes N sensors, M and N are integers greater than 1, wherein:

[0005] The sensors are respectively connected to the microcontroller and the power supply circuit;

[0006] The power supply circuit is used to supply power to the sensor;

[0007] The M sensor groups are respectively used to detect the output current of the M-phase output of the inverter connected to the motor, the M sensor groups correspond to the M-phase outputs one by one, and the N sensors included in each sensor group of the M sensor groups respectively detect the output current of the corresponding phase output in the M-phase outputs, the inverter is a K-phase inverter, and K is an integer greater than or equal to M;

[0008] The microcontroller is used to determine the target output current of the K-phase output of the inverter according to the output currents detected by the M sensor groups.

[0009] In a second aspect, an embodiment of the present application discloses a motor drive device, including an inverter and a current detection circuit disclosed in the first aspect;

[0010] The inverter is connected to the motor and is used to supply power to the motor.

[0011] In a third aspect, the present application discloses an electric vehicle, comprising the current detection circuit disclosed in the first aspect, or the motor drive device disclosed in the second aspect.

[0012] In the embodiment of the present application, the current detection circuit includes a microcontroller, a power supply circuit and M sensor groups, each of the M sensor groups includes N sensors; these sensors are respectively connected to the microcontroller and the power supply circuit; the power supply circuit supplies power to these sensors; the M sensor groups respectively detect the output current of the M phase output in the K phase output included in the inverter connected to the motor, the M sensor groups correspond to the M phase output one by one, and the N sensors included in each sensor group in the M sensor groups respectively detect the output current of the corresponding phase output in the M phase output; the microcontroller determines the target output current of the K phase output of the inverter according to the output current detected by the M sensor groups. It can be seen that the current detection circuit detects the output current of one phase output of the inverter to the motor through multiple sensors, and determines the final output current of this phase output through the multiple output currents of this phase output detected. Since the different output currents of the same phase output detected can be verified with each other, the current output of the inverter to the motor can be accurately detected by the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 is a structural schematic diagram of a current detection circuit disclosed in an embodiment of the present application;

[0015] Figure 2 is a structural schematic diagram of another current detection circuit disclosed in an embodiment of the present application;

[0016] Figure 3 is a structural schematic diagram of another current detection circuit disclosed in an embodiment of the present application;

[0017] Figure 4 It is a structural schematic diagram of a motor drive device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0019] The embodiments of the present application disclose a current detection circuit, a motor drive device and an electric vehicle, which are used to accurately detect the current output by an inverter to a motor through a sensor. Detailed descriptions are given below.

[0020] In order to better understand the embodiments of the present application, the relevant technologies of the embodiments of the present application are described below.

[0021] In order to detect the current output by the inverter to the motor, in one case, multiple sensors can be used to respectively detect the output current of the multi-phase output of the inverter, that is, each of the multiple sensors respectively detects the output current of one phase output of the multi-phase output of the inverter, that is, the multiple sensors correspond one-to-one to the multi-phase output of the inverter.

[0022] In another case, multiple sensors can be used to detect the output currents of some phase outputs of the inverter. Since the sum of the output currents of all phase outputs of the inverter is 0, the output current of the remaining phase output can be determined based on the output currents of the detected phase outputs.

[0023] In the above two detection methods, the output current of each phase output is detected by a sensor. However, as the sensor is used for a longer time, the sensor will age to varying degrees, causing a large deviation between the output current of each phase output of the inverter detected by the sensor and the actual output current, reducing the accuracy of current detection.

[0024] In order to solve the above problems, the present application designs a current detection circuit, including a microcontroller, a power supply circuit and M sensor groups, each of the M sensor groups includes N sensors; these sensors are respectively connected to the microcontroller and the power supply circuit; the power supply circuit supplies power to these sensors; the M sensor groups respectively detect the output current of the M phase output in the K phase output included in the inverter connected to the motor, the M sensor groups correspond to the M phase output one by one, and the N sensors included in each sensor group in the M sensor groups respectively detect the output current of the corresponding phase output in the M phase output; the microcontroller determines the target output current of the K phase output of the inverter according to the output current detected by the M sensor groups. It can be seen that the current detection circuit detects the output current of one phase output of the inverter to the motor through multiple sensors, and determines the final output current of the phase output through the multiple output currents of the detected phase output. Since the different output currents of the same phase output can be verified with each other, the current output of the inverter to the motor can be accurately detected by the sensor, which can improve the accuracy of current detection.

[0025] See also Figure 1 , Figure 1 Schematic diagram of a current detection circuit disclosed in an embodiment of the present application. Figure 1 As shown, the current detection circuit may include a microcontroller (Micro Control Unit, MCU), a power supply circuit and M sensor groups, each of the M sensor groups includes N sensors, and M and N are integers greater than 1.

[0026] The sensors are connected to the microcontroller and the power supply circuit respectively, that is, each sensor is connected to the microcontroller and the power supply circuit respectively.

[0027] Each of these sensors is independent of each other, and their operations will not affect each other, which can improve the accuracy of the current detected by each sensor.

[0028] The power supply circuit can supply power to the sensors so as to provide the sensors with power to work normally.

[0029] The M sensor groups respectively detect the output current of the M-phase output of the inverter connected to the motor, and the M sensor groups correspond to the M-phase output one by one. It can be seen that each sensor group in the M sensor groups respectively detects the output current of the corresponding one-phase output in the M-phase output of the inverter, which can ensure that the output current of the one-phase output of the inverter is detected by one sensor group, and can avoid the situation where the output current of the one-phase output of the inverter is detected by multiple sensor groups, which can reduce the demand for sensor groups and reduce the complexity and cost of the current detection circuit. The inverter is a K-phase inverter, and K is an integer greater than or equal to M. That is, the inverter is at least a three-phase inverter.

[0030] The N sensors included in each of the M sensor groups respectively detect the output current of the corresponding phase output in the M phase outputs. It can be seen that the N sensors included in one sensor group respectively detect the output current of the corresponding phase output in one phase output, that is, the output currents detected by the N sensors included in one sensor group are all output currents of the same phase output, and the N output currents of the same phase output detected can be mutually verified. Therefore, the accuracy of the final output current of the phase output determined according to the N output current outputs of the same phase output can be guaranteed, thereby improving the accuracy of the inverter output current detection.

[0031] After the sensor detects the output current, the detected output current can be sent to the microcontroller. The microcontroller can determine the target output current of the K-phase output of the inverter according to the output current detected by the M sensor groups.

[0032] When K is equal to M, the M sensor groups correspond to the K-phase output of the inverter one by one. It can be seen that each of the M sensor groups detects the output current of one phase output of the K-phase output of the inverter. Since the output current of each phase output of the inverter is detected by one sensor group, the current detection circuit can directly detect the output current of the K-phase output of the inverter through the M sensor groups, which can improve the current detection efficiency.

[0033] When K is greater than M, M=K-1, and the M sensor groups correspond one-to-one to the K-1 phase output of the inverter. The M sensor groups respectively detect the output current of the K-1 phase output of the inverter. It can be seen that each sensor group in the M sensor groups respectively detects the output current of one phase output in the K-1 phase output of the inverter.

[0034] The M sensor groups can detect the output current of the K-1 phase output of the inverter. Since the sum of the output currents of the K-phase output of the inverter is 0, after the M sensor groups detect the output current of the K-1 phase output of the inverter, the microcontroller can calculate the output current of the remaining phase output according to the output current of the K-1 phase output, and obtain the output current of the K-phase output of the inverter. It can be seen that the output current of the K-phase output of the inverter can be detected by M sensor groups, which can reduce one sensor group and the number of sensor groups, thereby reducing the complexity and cost of the current detection circuit.

[0035] The current detection directions of the N sensors included in a sensor group may be the same or different. The current detection direction is the detection direction of the current, that is, the direction of the detected current. The current detection direction of the sensor may be from the inverter to the motor, or from the motor to the inverter.

[0036] In some embodiments, when the current detection directions of the N sensors included in the first sensor group are all the same, the microcontroller can determine the target output current of the first phase output based on the output current detected by any two sensors included in the N sensors included in the first sensor group when the absolute value of the difference between the output currents detected by any two sensors included in the N sensors included in the first sensor group is less than a first threshold, the first sensor group is any sensor group among the M sensor groups, and the first phase output is a phase output corresponding to the first sensor group in the K-phase output of the inverter.

[0037] In the case that the current detection directions of the N sensors included in the first sensor group are all the same, after the microcontroller obtains the output current detected by the first sensor, it can first calculate the absolute value of the difference between the output currents detected by any two of the N sensors included in the first sensor group, and then determine whether the absolute value of the difference between the output currents detected by any two of the N sensors included in the first sensor group is less than the first threshold value. In the case that it is determined that the absolute value of the difference between the output currents detected by any two of the N sensors included in the first sensor group is less than the first threshold value, it indicates that the deviation of the output currents of the corresponding phase outputs detected by the N sensors included in the first sensor group is small, and the target output current of the first phase output can be determined according to the output currents detected by the N sensors in the first sensor group. The microcontroller can determine the output current detected by any sensor in the first sensor group as the target output current of the first phase output, or determine the average value of the output currents detected by the N sensors in the first sensor group as the target output current of the first phase output.

[0038] When it is determined that the absolute value of the difference in output current detected by two sensors among the N sensors included in the first sensor group is greater than or equal to the first threshold, it indicates that the output current detected by one of the N sensors is inaccurate due to aging or other reasons. When N is greater than 2, the microcontroller can cluster the N sensors according to the first threshold and the output current detected by the N sensors to obtain L sensor classes. L is an integer greater than 1. Each of the L sensor classes includes one or more sensors. When a sensor class includes multiple sensors, the absolute value of the difference in output current detected by any two sensors among the multiple sensors is less than the first threshold. The microcontroller can determine the target output current of the first phase output based on the output current detected by a sensor class with the largest number of sensors included in the L sensor classes.

[0039] When N is equal to 2 and K is equal to M, if the absolute value of the difference in output current detected by any two sensors of the N sensors included in the M-1 sensor groups is less than the first threshold, the microcontroller can first determine the target output current of the corresponding K-1 phase output according to the output current detected by the M-1 sensor groups, and then determine the first output current of the remaining sensor group corresponding to one phase output according to the target output current of the K-1 phase output, and then select the output current whose absolute value of the difference with the first output current is less than or equal to the second threshold from the output currents detected by the N sensors included in this sensor group, and then determine the output current of this phase output according to the selected output current. The first threshold and the second threshold can be the same or different.

[0040] In some embodiments, when the current detection directions of N sensors included in the first sensor group are different, the microcontroller determines the target output current of the first phase output according to the output current detected by N sensors in the first sensor group when the absolute value of the difference between the absolute values ​​of the output currents detected by any two sensors in the N sensors included in the first sensor group is less than a first threshold value, the first sensor group is any sensor group among the M sensor groups, and the first phase output is a phase output corresponding to the first sensor group in the K-phase output of the inverter.

[0041] When the current detection directions of the N sensors included in the first sensor group are different, the method of determining the target output current of the first phase output is similar to the method of determining the target output current of the first phase output when the current detection directions of the N sensors included in the first sensor group are the same, with the difference that one determines the absolute value of the difference between the output currents detected by two sensors, and the other determines the absolute value of the difference between the absolute values ​​of the output currents detected by the two sensors.

[0042] The current detection directions of the N sensors included in the first sensor group are different, and the current detection directions of the N sensors are all different. Exemplarily, when N is 2, the current detection directions of the two sensors are opposite, one is used to detect the current from the inverter to the motor, and the other is used to detect the current from the motor to the inverter.

[0043] The current detection directions of the N sensors included in the first sensor group are different, and the current detection directions of the N sensors may be partially different. Exemplarily, when N is 3, the current detection directions of two sensors among the three sensors are different from the current detection direction of another sensor.

[0044] In the case where the current detection directions of the first sensor and the second sensor included in the first sensor group are different, the microcontroller may also calculate the sum of the output currents detected by the first sensor and the second sensor, and then determine whether the absolute value of the sum is less than the first threshold value. In the case where it is determined that the absolute value of the sum is less than the first threshold value, it can be determined that the deviation of the output currents detected by the first sensor and the second sensor is small. In the case where it is determined that the absolute value of the sum is greater than or equal to the first threshold value, it can be determined that the deviation of the output currents detected by the first sensor and the second sensor is large.

[0045] Exemplarily, when N is 2 and the current detection directions of the two sensors are different, the microcontroller can calculate the sum of the output currents detected by the two sensors, and then determine whether the absolute value of the sum is less than the first threshold value. When it is determined that the absolute value of the sum is less than the first threshold value, the output current of the corresponding phase output can be determined according to the output currents detected by the two sensors. The microcontroller can determine the output current detected by any one of the two sensors as the target output current of the corresponding phase output, or determine the average value of the absolute values ​​of the output currents detected by the two sensors as the target output current of the corresponding phase output.

[0046] When N is 2 and the current detection directions of the two sensors are different, the two sensors can be back-to-back.

[0047] When the absolute value of the difference in output current detected by two sensors among the N sensors included in a sensor group is greater than or equal to a first threshold, the microcontroller can also output a prompt message for prompting the user that there is a problem with the sensor group, so that the user can check and / or replace the sensors of the sensor group according to the prompt message, thereby ensuring the effectiveness of the sensors in the current detection circuit and improving the accuracy of the detected current.

[0048] The sensor can be a sensor mounted on a copper busbar or a magnetic sensor.

[0049] Exemplarily, the sensor may be a magnetic sensor that converts a perpendicular magnetic field into a parallel magnetic field using a built-in magnetic collecting sheet, which may be realized by placing two magnetic collecting sheets on a chip. The chip may be a highly integrated Hall sensor that provides an output signal proportional to the horizontally applied magnetic flux density, so it is suitable for current measurement, and it has a small size and high accuracy.

[0050] For example, when N is 2, the current flowing through the copper bar generates a magnetic field, and the magnetic field hits the sensor chip, which will generate a corresponding voltage value. The two sensors, sensor 1 and sensor 2, are placed back to back, and their main function is to obtain a voltage value of equal magnitude and opposite direction at the same time and input it into the microprocessor.

[0051] exist Figure 1In the described current detection circuit, the current detection circuit detects the output current of one phase output of the inverter to the motor through multiple sensors, and determines the final output current of this phase output through the detected multiple output currents of this phase output. Since different output currents of the same phase output detected can be mutually verified, the current output of the inverter to the motor can be accurately detected through the sensor, which can improve the accuracy of current detection. In addition, in the case that some sensors in the sensor group fail, the current can continue to be detected through the sensors that have not failed, which can improve the fault tolerance and applicability of the current detection circuit.

[0052] See also Figure 2 , Figure 2 is a schematic diagram of the structure of another current detection circuit disclosed in the embodiment of the present application. Figure 2 The current sensing circuit shown is composed of Figure 1 The current detection circuit shown is optimized. Figure 2 As shown, the power supply circuit may include a first power supply module, a second power supply module and a power supply selection module.

[0053] The power supply selection module is connected to the first power supply module, the second power supply module and the sensors respectively. The power supply selection module can determine the power supply modules of the sensors according to the output voltages of the first power supply module and the second power supply module. Specifically, the power supply selection module can determine the power supply module with the largest output voltage among the first power supply module and the second power supply module as the power supply module of the sensors.

[0054] The voltages of the power supplies included in the first power supply module and the second power supply module are different, and the output voltages of the first power supply module and the second power supply module are also different. The first power supply module can be called a low-voltage power supply module, and the second power supply module can be called a high-voltage power supply module. That is, the voltage of the power supply of the first power supply module is less than the voltage of the power supply included in the second power supply module.

[0055] At the same time, one of the first power supply module and the second power supply module supplies power to the sensors, which can reduce the number of power supply modules used. In addition, since the power supply circuit includes two power supply modules, when one of the power supply modules fails, the other power supply module can be used to supply power to the sensors, which can ensure that the current detection is normal, the motor can be controlled normally, and the probability of failure of the electronic equipment can be reduced.

[0056] For example, when the motor is used in an electric vehicle, the two power supply modules can reduce the probability of sudden braking of the electric vehicle and improve the safety of the user.

[0057] See also Figure 3 , Figure 3is a structural diagram of another current detection circuit disclosed in the embodiment of the present application. Figure 3 The current sensing circuit shown is composed of Figure 2 The current detection circuit shown is optimized. Figure 3 As shown, the first power supply module may include a low-voltage DC power supply and a first linear voltage regulator unit. The first linear voltage regulator unit is connected to the low-voltage DC power supply and the power supply selection module respectively. The first linear voltage regulator unit can convert the first DC power provided by the low-voltage DC power supply into a second DC power of a first preset voltage.

[0058] like Figure 3 As shown, the second power supply module may include a high-voltage DC power supply, a DC-DC conversion unit, and a second linear voltage stabilizing unit. The high-voltage DC power supply is connected to the DC-DC conversion unit, and the second linear voltage stabilizing unit is respectively connected to the DC-DC conversion unit and the power supply selection module. The DC-DC conversion unit can convert the third DC power provided by the high-voltage DC power supply into a fourth DC power, and the second linear voltage stabilizing unit can convert the fourth DC power into a fifth DC power of a second preset voltage, wherein the voltage of the fourth DC power is less than the voltage of the third DC power and greater than the second preset voltage.

[0059] The output voltage of the low voltage DC power supply is lower than the output voltage of the high voltage DC power supply.

[0060] The gap between the output voltage of the high-voltage DC power supply and the second preset voltage is large. Directly using the linear voltage regulator unit to convert the DC signal output by the high-voltage DC power supply into the required DC signal consumes a lot of power and has poor isolation effect. Exemplarily, the output voltage of the high-voltage DC power supply is 400V or 800V, and the second preset voltage is 5V. In order to avoid these problems, a DC-DC conversion unit is connected between the second linear voltage regulator unit and the high-voltage DC power supply to achieve voltage reduction and high voltage isolation.

[0061] Due to the importance of current sampling and the high requirements for sensor accuracy, a relatively stable power supply voltage is required for the sensor. Therefore, the linear voltage regulator unit can use a high-precision low drop-out linear regulator (Low Drop-Out Regulator, LDO).

[0062] Normally, the low voltage will be powered on first for self-test. In addition, the fluctuation of the low voltage is more stable than that of the high voltage. Therefore, the first preset voltage can be greater than the second preset voltage to ensure that all sensors are powered by the low voltage power supply under normal circumstances. In the event of a failure of the low voltage power supply, the high voltage power supply will power the sensor.

[0063] See also Figure 4 , Figure 4 Schematic diagram of the structure of a motor drive device disclosed in the embodiment of the present application. Figure 4As shown, the motor drive device may include an inverter and a current detection circuit;

[0064] The inverter is connected to the motor and can provide power to the motor.

[0065] For a detailed description of the current detection circuit, please refer to the above related description.

[0066] The above-mentioned current detection circuit can be applied to all electronic devices provided with a motor.

[0067] Exemplarily, the above-mentioned current detection circuit may be applied in an electric vehicle, that is, the electric vehicle may include the above-mentioned current detection circuit.

[0068] Exemplarily, the above-mentioned current detection circuit may be applied in a robot, that is, the robot may include the above-mentioned current detection circuit.

[0069] Exemplarily, the above-mentioned current detection circuit may be applied in an air conditioner, that is, the air conditioner may include the above-mentioned current detection circuit.

[0070] Exemplarily, the above-mentioned current detection circuit may be applied in an electric power device, that is, the electric power device may include the above-mentioned current detection circuit.

[0071] The motor driving device can be applied to all electronic devices provided with a motor.

[0072] Exemplarily, the motor drive device may be applied in an electric vehicle, that is, the electric vehicle may include the motor drive device.

[0073] Exemplarily, the motor drive device may be applied in a robot, that is, the robot may include the motor drive device.

[0074] Exemplarily, the motor driving device may be applied in an air conditioner, that is, the air conditioner may include the motor driving device.

[0075] Exemplarily, the motor drive device may be applied in an electric power device, that is, the electric power device may include the motor drive device.

[0076] It should be understood that the connection in this application can be understood as an electrical connection.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A current detection circuit, characterized in that: The invention comprises a microcontroller, a power supply circuit and M sensor groups, each of the M sensor groups comprises N sensors, M and N are integers greater than 1, wherein: The sensors are respectively connected to the microcontroller and the power supply circuit; The power supply circuit is used to supply power to the sensor; The M sensor groups are respectively used to detect the output current of the M-phase output of the inverter connected to the motor, the M sensor groups correspond to the M-phase outputs one by one, and the N sensors included in each sensor group of the M sensor groups respectively detect the output current of the corresponding phase output in the M-phase outputs, the inverter is a K-phase inverter, and K is an integer greater than or equal to M; The microcontroller is used to determine the target output current of the K-phase output of the inverter according to the output currents detected by the M sensor groups.

2. The current detection circuit according to claim 1, characterized in that: In a case where the current detection directions of the N sensors included in the first sensor group are the same, the microcontroller is specifically used to determine the target output current of the first phase output according to the output current detected by the N sensors included in the first sensor group when the absolute value of the difference between the output currents detected by any two sensors among the N sensors included in the first sensor group is less than a first threshold, the first sensor group being any sensor group among the M sensor groups, and the first phase output being a phase output corresponding to the first sensor group in the K-phase output of the inverter.

3. The current detection circuit according to claim 1, characterized in that: In a case where the current detection directions of the N sensors included in the first sensor group are different, the microcontroller is specifically used to determine the target output current of the first phase output according to the output current detected by the N sensors included in the N sensors included in the first sensor group, when the absolute value of the difference between the absolute values ​​of the output currents detected by any two sensors among the N sensors included in the first sensor group is less than a first threshold, the first sensor group is any sensor group among the M sensor groups, and the first phase output is a phase output corresponding to the first sensor group in the K-phase output of the inverter.

4. The current detection circuit according to claim 1, characterized in that: The power supply circuit includes a first power supply module, a second power supply module and a power supply selection module; The power supply selection module is respectively connected to the first power supply module, the second power supply module and the sensor; The power supply selection module is used to determine the power supply module of the sensor according to the output voltages of the first power supply module and the second power supply module.

5. The current detection circuit according to claim 4, characterized in that: The power supply selection module is specifically used to determine the power supply module with the largest output voltage between the first power supply module and the second power supply module as the power supply module of the sensor.

6. The current detection circuit according to claim 4, characterized in that: The first power supply module includes a low-voltage DC power supply and a first linear voltage stabilizing unit; The first linear voltage stabilizing unit is respectively connected to the low-voltage DC power supply and the power supply selection module; The first linear voltage stabilizing unit is used to convert the first direct current provided by the low-voltage direct current power supply into a second direct current with a first preset voltage.

7. The current detection circuit according to claim 6, characterized in that: The second power supply module includes a high-voltage DC power supply, a DC-DC conversion unit and a second linear voltage stabilization unit; The high-voltage DC power supply is connected to the DC-DC conversion unit, and the second linear voltage stabilization unit is connected to the DC-DC conversion unit and the power supply selection module respectively; The DC-DC conversion unit is used to convert the third DC power provided by the high-voltage DC power supply into a fourth DC power; The second linear voltage stabilizing unit is used to convert the fourth direct current into a fifth direct current of a second preset voltage, wherein the voltage of the fourth direct current is lower than the voltage of the third direct current and higher than the second preset voltage.

8. The current detection circuit according to claim 7, characterized in that: The first preset voltage is greater than the second preset voltage.

9. A motor drive device, characterized in that: comprising an inverter and a current detection circuit as claimed in any one of claims 1 to 8; The inverter is connected to the motor and is used to supply power to the motor.

10. An electric vehicle, characterized in that: It comprises the current detection circuit as described in any one of claims 1 to 8, or the motor drive device as described in claim 9.

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