A motor initial angle self-calibration circuit, controller, drive assembly, and vehicle.

Abstract

This utility model discloses a motor initial angle self-calibration circuit, controller, drive assembly, and vehicle. The circuit includes a sampling unit and a sampling processing unit. The sampling unit is disposed within an electrical insulation gap between the high-voltage circuit area and the low-voltage circuit area. The sampling unit is used to collect the phase voltage of the motor. The sampling processing unit is connected to the sampling unit and is used to calibrate the initial angle of the motor based on the phase voltage. In this utility model, placing the sampling unit for motor initial angle calibration within the electrical insulation gap avoids reserving space for the sampling unit on the PCBA board, making the calibration circuit structure more compact and concise, and helping to improve the layout rationality and stability of the entire calibration circuit.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a self-calibration circuit for the initial angle of a motor. Background Technology

[0002] Automotive permanent magnet synchronous motors use resolvers or eddy currents to mark the actual position of the rotor. By determining the position of the resolver or eddy current, the phase position of the motor's stator and rotor can be determined, thereby achieving precise torque control.

[0003] Since the stator, rotor, resolver (eddy current) stator, and resolver (eddy current) rotor of a permanent magnet synchronous motor may be randomly positioned during installation, the phase position of the permanent magnet synchronous motor stator and rotor may not be completely consistent with the phase position of the resolver (eddy current) stator and rotor, but there may be a fixed angular deviation. Therefore, an initial angle calibration needs to be performed before the electric drive is put into operation. This deviation is tested and written into the controller, which is the initial angle calibration of the motor.

[0004] In existing technologies, initial angle calibration of motors typically requires the use of multiple sampling resistors, and the sampled signals need to be isolated from high voltage to low voltage before being transmitted to subsequent circuits. This method requires a significant amount of PCBA space and is therefore costly. Utility Model Content

[0005] This utility model provides a motor initial angle self-calibration circuit, controller, drive assembly, and vehicle to solve at least one defect in the prior art.

[0006] In a first aspect, this utility model embodiment provides a motor initial angle self-calibration circuit, including a sampling unit and a sampling processing unit;

[0007] The sampling unit is located within the electrical insulation gap between the high-voltage circuit area and the low-voltage circuit area;

[0008] The sampling unit is used to collect the phase voltage of the motor;

[0009] The sampling processing unit is connected to the sampling unit, and the sampling processing unit is used to calibrate the initial angle of the motor based on the phase voltage.

[0010] Optionally, the sampling processing unit is further configured to: use the square wave signal to determine the position reference value of the phase position of the stator and rotor of the motor at a preset time;

[0011] The position measurement values ​​of the phase positions of the stator and rotor of the motor at the preset time are obtained, and the difference between the position reference value and the position measurement value is calibrated as the initial angle of the motor.

[0012] Optionally, the sampling unit includes a first sampling unit and a second sampling unit; the first sampling unit and the second sampling unit are used to sample the phase voltages of two phases in the motor drive circuit, respectively.

[0013] The sampling processing unit includes a differential operational amplifier circuit, a comparator circuit, and a control unit;

[0014] The first and second input terminals of the differential operational amplifier circuit are respectively connected to the output terminals of the first and second sampling units, and are used to perform differential processing on the sampled phase voltage signals of the two phases.

[0015] The first input terminal of the comparator circuit is connected to the output terminal of the differential operational amplifier circuit, and the second input terminal of the comparator circuit is used to connect a reference voltage to process the signal output by the differential operational amplifier circuit into a square wave signal.

[0016] The control unit is connected to the output of the comparison circuit. The control unit is used to identify the falling edge of the square wave signal, take the time when the falling edge is identified as the preset time, take the preset angle corresponding to the falling edge as the position reference value, and calculate the difference between the position reference value and the position measurement value as the initial angle of the motor.

[0017] Optionally, the sampling unit includes at least one first sampling resistor and at least one second sampling resistor;

[0018] The first sampling resistor is connected in series between the first sampling point of the motor drive circuit and the first input terminal of the sampling processing unit.

[0019] The second sampling resistor is connected in series at the second sampling point of the motor drive circuit and the second input terminal of the sampling processing unit;

[0020] The first sampling point and the second sampling point are respectively set on any two different bridge arms of the motor drive circuit.

[0021] Optionally, the differential operational amplifier circuit includes an operational amplifier, the amplification factor of which is determined according to the following formula:

[0022] kop≤up / (2uin_comp)

[0023] In the formula, kop represents the amplification factor, up represents the maximum value of the phase voltage of the motor, and uin_comp represents the input voltage threshold of the comparator.

[0024] Optionally, the comparison circuit includes a comparator configured to output a PWM wave with a duty cycle of 0.5.

[0025] Optionally, the motor drive circuit is electrically connected to a DC bus, and the voltage of the DC bus is at least 800V.

[0026] Optionally, the electrical insulation gap is at least 4.5 mm, and the electrical insulation gap is the air distance between the high-voltage circuit area and the low-voltage circuit area.

[0027] Optionally, the withstand voltage of the first sampling resistor and the second sampling resistor is greater than the maximum value of the phase voltage, and the resistance values ​​of the first sampling resistor and the second sampling resistor are at least greater than 5MΩ.

[0028] Optionally, on the circuit board corresponding to the high-voltage circuit area, the creepage distance between the first conductive part and the second conductive part is at least 3.8 mm;

[0029] The first conductive part is one of the pins, pads, and traces corresponding to the first sampling resistor, and the second conductive part is one of the pins, pads, and traces corresponding to the second sampling resistor.

[0030] Optionally, the phase voltage can be any two phase voltages of a three-phase sinusoidal voltage.

[0031] The motor drive circuit is configured to generate the three-phase sinusoidal voltage when the motor is idling at a preset speed.

[0032] Secondly, this utility model embodiment also provides a motor controller that stores an initial motor angle, wherein the initial motor angle is determined by any of the initial motor angle self-calibration circuits described in this utility model embodiment.

[0033] Thirdly, this utility model embodiment also provides a motor drive assembly, including a motor controller, a motor drive circuit, a sampling unit, and a signal processing unit;

[0034] The sampling unit is disposed within an electrical insulation gap between the high-voltage circuit area and the low-voltage circuit area. The high-voltage circuit area includes the motor drive circuit, and the low-voltage circuit area includes the motor controller and the signal processing unit. The electrical insulation gap is used for electrical isolation between the high-voltage circuit area and the low-voltage circuit area.

[0035] The sampling unit is connected between the sampling point of the motor drive circuit and the signal processing unit, and the sampling unit is used to sample the phase voltage of two phases in the motor drive circuit.

[0036] The signal processing unit is connected to the sampling unit, and the signal processing unit is used to compare the phase voltages of the two sampled phases and process them into a square wave signal.

[0037] The motor controller is connected to the output terminal of the signal processing unit, and the motor controller is configured to calibrate the initial angle of the motor based on the square wave signal.

[0038] Fourthly, this utility model embodiment also provides a vehicle, including any of the motor initial angle self-calibration circuits described in this utility model embodiment.

[0039] Compared with existing technologies, the advantages of this invention are as follows: This invention proposes a self-calibration circuit for the initial angle of a motor. This circuit collects the two-phase voltage of the motor drive circuit in real time through a sampling unit, and then automatically converts it into a square wave signal for angle calibration through a sampling processing unit, thus realizing automatic calibration of the initial angle of the motor. By placing the sampling unit for the initial angle calibration within an electrical insulation gap, it avoids reserving space for the sampling unit on the PCBA board, making the calibration circuit structure more compact and concise, and contributing to the improvement of the overall layout rationality and stability of the calibration circuit. Attached Figure Description

[0040] Figure 1 This is a block diagram of the motor initial angle self-calibration circuit structure in the embodiment;

[0041] Figure 2 This is a schematic diagram of the motor phase voltage differential signal in the embodiment;

[0042] Figure 3 This is a block diagram of another battery initial angle self-calibration circuit structure in the embodiment. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0044] Example 1

[0045] Figure 1 This is a block diagram of the motor initial angle self-calibration circuit in the embodiment, for reference. Figure 1 The motor initial angle self-calibration circuit includes a sampling unit 100 and a sampling processing unit 200.

[0046] The sampling unit 100 is disposed in the electrical insulation gap between the high-voltage circuit area and the low-voltage circuit area. The high-voltage circuit area includes the motor drive circuit 1, and the low-voltage circuit area includes the sampling processing unit 200. The electrical insulation gap is used for electrical isolation between the high-voltage circuit area and the low-voltage circuit area.

[0047] The sampling unit 100 is connected between the sampling point of the motor drive circuit 1 and the sampling processing unit 200. The sampling unit 100 is used to sample the phase voltage of two phases in the motor drive circuit 1, that is, the sampling unit 100 is used to collect the phase voltage of the motor.

[0048] In this scheme, the sampling processing unit 200 is connected to the sampling unit 100, and the sampling processing unit 200 is used to calibrate the initial angle of the motor based on the phase voltage.

[0049] For example, in this solution, the sampling processing unit 200 is connected to the sampling unit 100. The sampling processing unit 200 is used to compare the phase voltages of the two sampled phases and process them into square wave signals. The square wave signals are used to calibrate the initial angle of the motor.

[0050] For example, in this solution, the bus voltage corresponding to the high-voltage circuit area can be 200V to 1000V, and the high-voltage circuit area can house a motor, power battery, motor drive circuit, etc. The bus voltage corresponding to the low-voltage circuit area can be less than 60V, and the low-voltage circuit area can house an MCU (Microcontroller Unit) and functional circuits connected to the MCU, etc.

[0051] In this solution, the electrical insulation gap refers to the air distance between the high-voltage circuit area and the low-voltage circuit area. The electrical insulation gap can be formed by reasonably arranging the positions of the circuit board areas corresponding to the high-voltage circuit area and the circuit board areas corresponding to the low-voltage circuit area.

[0052] For example, in this solution, the size of the electrical insulation gap is determined according to the bus voltage level corresponding to the high-voltage circuit area and the minimum electrical insulation gap specified by different manufacturers. For example, the electrical insulation gap can be at least 4mm.

[0053] In this scheme, the motor drive circuit can use a three-phase inverter, and the sampling point on the bridge arm of the motor drive circuit can be the output terminal of any two different bridge arms in the three-phase inverter (e.g., the output terminal of the u-phase bridge arm and the output terminal of the v-phase bridge arm).

[0054] For example, in this solution, the unit 100 may include several sampling resistors. The sampling resistors are mainly used to convert the current signal of the bridge arm into a voltage signal, thereby realizing voltage sampling of the specified phase voltage of the motor drive circuit.

[0055] When sampling phase voltage using a sampling resistor, the creepage distance in high-voltage areas needs to be considered (for example, if the bus circuit in the high-voltage area is 800V, the creepage distance must be 3.8mm). This condition becomes an important factor limiting the selection of sampling resistors.

[0056] Taking the 0805 sampling resistor as an example, the pad spacing of a single 0805 package resistor is usually 0.8mm. When the sampling resistor is placed on the PCBA board, at least 6 of these package resistors are needed for single-phase sampling (considering the margin, a 1000V withstand voltage needs to be designed), and at least 12 are needed for two-phase sampling, which occupies a lot of PCBA board area.

[0057] In this design, the sampling resistor is placed in the electrical insulation gap. This layout avoids reserving space for the sampling resistor at the PCBA board end, making the structure of the high-voltage circuit area more compact and simple, which helps to improve the layout rationality and stability of the entire high-voltage circuit area.

[0058] In this scheme, the phase positions of the stator and rotor of the permanent magnet synchronous motor output by the rotary transformer (or eddy current sensor) are denoted as the first angle, and the phase positions of the stator and rotor of the permanent magnet synchronous motor are denoted as the second angle. The motor initial angle self-calibration circuit is used to determine the angle deviation between the first angle and the second angle.

[0059] In this scheme, the initial angle of the motor is the angular deviation between the first angle and the second angle, which reflects the measurement error of the rotary transformer (or eddy current sensor).

[0060] In this scheme, a sampling processing unit is used to compare the phase voltages of the two sampled phases and process them into square wave signals, which are then used to calibrate the initial angle of the motor.

[0061] For example, in this solution, the sampling processing unit may include a comparator chip. Taking the phase voltages Uu and Uv of phases u and v as an example, the comparator chip can determine the moment when Uu changes from higher than Uv to lower than Uv, and thus determine the falling edge of the square wave signal. It can also determine the moment when Uu changes from lower than Uv to higher than Uv, and thus determine the rising edge of the square wave signal, thereby forming a square wave signal.

[0062] In this scheme, the falling edge of the square wave signal corresponds to a certain phase position of the stator and rotor of the motor. If the measured value of the phase position of the stator and rotor of the motor at this certain moment is obtained, the initial angle of the motor can be determined by calculating the angle deviation between the first angle and the second angle.

[0063] This embodiment proposes a self-calibration circuit for the initial angle of a motor. This circuit uses a sampling unit to collect the two-phase voltages in the motor drive circuit in real time, and then a sampling processing unit automatically converts them into square wave signals for angle calibration, thus achieving automatic calibration of the motor's initial angle. By placing the sampling unit for initial angle calibration within an electrical insulation gap, it avoids reserving space for the sampling unit on the PCBA board, making the calibration circuit structure more compact and concise, and contributing to the improved layout rationality and stability of the entire calibration circuit.

[0064] In this scheme, if the resistance value of the resistor reaches a certain value (for example, meeting the specified high and low voltage insulation impedance standards), the sampling resistor can also be used as the insulation resistance between the high and low voltage circuit areas, so as to avoid high voltage damage to the devices in the low voltage circuit area.

[0065] Based on any of the aforementioned schemes, in one possible implementation, the sampling processing unit is further used to: determine the phase position of the stator and rotor of the motor at a preset time using a square wave signal, and the position reference value of the motor rotor.

[0066] Obtain the position measurement values ​​of the phase position of the stator and rotor of the motor at a preset time, and calibrate the difference between the position reference value and the position measurement value as the initial angle of the motor.

[0067] For example, in this solution, the sampling processing unit may include a comparator circuit and an MCU. The comparator circuit may include a comparator chip, which generates a square wave signal.

[0068] Configure the comparator chip's output to connect to the MCU, configure the MCU to detect the falling edge of the square wave signal, and calibrate the initial angle of the motor.

[0069] For example, in this solution, a rotary transformer can be configured to be connected to the MCU through a sensor interface circuit. The rotary transformer is used to measure the phase position of the stator and rotor of the motor, and the sensor interface circuit is used to amplify, filter, and perform analog-to-digital conversion on the signal output by the rotary transformer to form a position measurement value.

[0070] For example, in this scheme, the preset time can be the time corresponding to any falling edge of the square wave signal, and the position reference value is an angle value corresponding to the falling edge when using the specified two-phase phase voltages. For example, if the phase voltages of phases u and v are used, the position reference value can be 150°, and if the phase voltages of phases u and w are used, the position reference value can be 30°.

[0071] In this scheme, a sampling processing unit is configured to detect the falling edge of the square wave signal. By determining the position reference value and position measurement value corresponding to the falling edge, the relative relationship between the two can be quickly established, thereby enabling rapid automatic calibration of the initial angle of the motor.

[0072] Based on any of the aforementioned schemes, in one possible implementation, the sampling unit includes a first sampling unit and a second sampling unit; the first sampling unit and the second sampling unit are used to sample the phase voltages of two phases in the motor drive circuit, respectively.

[0073] The sampling processing unit includes a differential operational amplifier circuit, a comparator circuit, and a control unit.

[0074] The first and second input terminals of the differential operational amplifier circuit are respectively connected to the output terminals of the first and second sampling units, and are used to perform differential processing on the sampled phase voltage signals of the two phases.

[0075] The first input terminal of the comparator circuit is connected to the output terminal of the differential operational amplifier circuit, and the second input terminal of the comparator circuit is used to connect a reference voltage to process the signal output by the differential operational amplifier circuit into a square wave signal.

[0076] The control unit is connected to the output of the comparator circuit. The control unit is used to identify the falling edge of the square wave signal, take the moment when the falling edge is identified as the preset moment, take the preset angle corresponding to the falling edge as the position reference value, and calculate the difference between the position reference value and the position measurement value as the initial angle of the motor.

[0077] For example, in this solution, the first sampling unit is used to sample the u-phase voltage, and the first sampling unit is used to sample the v-phase voltage. The sampling principle of the two phase voltages is the same. Taking the u-phase voltage sampling as an example, its sampling principle is as follows:

[0078] The first sampling unit is connected in series between the u-phase circuit and the differential operational amplifier circuit. When current flows through the first sampling unit, the u-phase voltage generates a certain proportion of voltage drop across the first sampling unit. This voltage drop can reflect the voltage value of the u-phase voltage, thereby realizing the sampling of the u-phase voltage.

[0079] In this design, the differential operational amplifier circuit may include an operational amplifier and peripheral circuitry. The operational amplifier is used to generate a differential signal based on the sampled voltages of phases u and v. The required amplification factor can be designed according to the amplitude of the voltage sampled signal and the voltage range of the input terminal of the comparator circuit. The output voltage of the differential operational amplifier circuit should not exceed the voltage range of the input port of the comparator circuit.

[0080] In this scheme, the comparison circuit may include a comparator, which is used to generate a square wave signal based on the differential signal. The output voltage of the comparator can be determined according to the port voltage range of the control unit. The output voltage of the comparison circuit should not exceed the port voltage range of the control unit.

[0081] In this solution, the control unit may include a microcontroller unit (MCU). The model of the MCU can be selected according to the requirements. For example, an STM32 series MCU or a TMS320 series DSP can be used.

[0082] In this scheme, the control unit is configured to monitor the output signal of the comparator circuit through the digital input port. When a jump in the output signal of the comparator circuit is detected, the state at the time of the jump (rising edge or falling edge) is recorded. When a falling edge is detected, the initial angle of the motor is calibrated.

[0083] For example, in this solution, the phase voltage is set to any two phase voltages of the three-phase sinusoidal voltage; the motor drive circuit is configured to generate a three-phase sinusoidal voltage when the motor is idling at a preset speed.

[0084] Figure 2 This is a schematic diagram of the motor phase voltage differential signal in the embodiment, for reference. Figure 2 When the motor is idling, the motor drive circuit (three-phase inverter) generates a three-phase sinusoidal voltage.

[0085] The first bridge arm of the three-phase inverter corresponds to the u-phase voltage, and the second bridge arm corresponds to the v-phase voltage. By sampling through the first and second sampling units, the sampled values ​​of the u-phase voltage and the v-phase voltage can be obtained. The sampled values ​​of the u-phase voltage and the v-phase voltage are differentially divided to obtain a differential signal. The differential signal is then further processed to obtain a square wave signal.

[0086] Specifically, the intersection of the u-phase voltage and the v-phase voltage (sine curve) corresponds to the falling edge of the square wave signal. This intersection satisfies that Vu (u-phase voltage value) equals Vv (v-phase voltage value) and at the next moment after this intersection, Vu is less than Vv. The phase position of the stator and rotor corresponding to this falling edge is set to 150° as the position reference value.

[0087] When the motor is idling, when the falling edge of the above square wave signal is detected, the phase position of the stator and rotor measured by the rotary transformer (or eddy current sensor) is recorded as the position measurement value.

[0088] When a falling edge is detected, the difference between the position reference value and the position measurement value is calculated as the initial angle of the motor.

[0089] In this scheme, the sampling unit is designed to include a first sampling unit and a second sampling unit. Using the first and second sampling units to synchronously sample the two-phase voltages ensures the sampling accuracy of the phase voltages. The sampling processing unit includes a differential operational amplifier circuit, a comparator circuit, and a control unit. The differential operational amplifier circuit generates a sine wave with a certain bias, ensuring that its output voltage does not exceed the pin voltage range of the comparator circuit. Using the differential operational amplifier circuit, comparator circuit, and control unit in tandem for motor initial angle calibration simplifies the hardware design while meeting the functional requirement of self-calibration of the motor's initial angle.

[0090] Based on any of the aforementioned schemes, in one possible implementation, the sampling unit includes at least one first sampling resistor and at least one second sampling resistor.

[0091] The first sampling resistor is connected in series between the first sampling point of the motor drive circuit and the first input terminal of the sampling processing unit. The second sampling resistor is connected in series between the second sampling point of the motor drive circuit and the second input terminal of the sampling processing unit.

[0092] The first sampling point and the second sampling point are respectively set on any two different bridge arms of the motor drive circuit.

[0093] Figure 3 This is a block diagram of another battery initial angle self-calibration circuit structure in the embodiment, for reference. Figure 3 As one possible implementation, the sampling unit includes a first sampling resistor Ra and a second sampling resistor Rb, and the sampling processing unit includes an operational amplifier U1, a comparator U2, and a controller U3.

[0094] The sampling points of the u and v phase bridge arms of the motor drive circuit are electrically connected to the first and second input terminals of the operational amplifier U1 through the first sampling resistor Ra and the second sampling resistor Rb, respectively.

[0095] The output of operational amplifier U1 is electrically connected to the first input of comparator U2, and the second input of comparator U2 is connected to a reference voltage.

[0096] The output of comparator U2 is electrically connected to controller U3, which is used to determine the initial angle of the motor.

[0097] For example, in this solution, a first sampling resistor Ra and a second sampling resistor Rb with appropriate resistance values ​​are selected according to the voltage and current range of the motor inverter unit. If the voltage of the motor inverter unit is high, a sampling resistor with a larger resistance value can be selected to ensure that a measurable voltage signal is obtained within a safe power range.

[0098] refer to Figure 3 For example, in this solution, on the circuit board corresponding to the high-voltage circuit area, the creepage distance between the first conductive part and the second conductive part is at least 3.8 mm.

[0099] The first conductive part is one of the pins, pads, and traces corresponding to the first sampling resistor Ra, and the second conductive part is one of the pins, pads, and traces corresponding to the second sampling resistor Rb.

[0100] In this solution, the creepage distance can be set according to the manufacturer's specific requirements. For example, depending on actual needs, the creepage distance can be greater than 3.8mm.

[0101] Based on the aforementioned sampling processing unit comprising operational amplifier U1, comparator U2, and controller U3, in one possible implementation, the amplification factor of the operational amplifier is determined according to the following formula:

[0102] kop≤up / (2uin_comp)

[0103] In the formula, kop represents the amplification factor, up represents the maximum value of the phase voltage of the motor, and uin_comp represents the input voltage threshold of the comparator.

[0104] For example, in this scheme, up is the maximum value of the phase voltage of the motor, which is usually 1000V, and different values ​​can be selected according to different requirements; uin_comp is usually 5V, which varies depending on the comparator model; 2 times is because one phase is used as the reference, and the relative amplitude range of the voltage of the other phase is -Up to Up.

[0105] Based on the aforementioned sampling processing unit including operational amplifier U1, comparator U2 and controller U3, in one possible implementation, the reference voltage is the bias voltage of the operational amplifier.

[0106] In this scheme, the bias voltage of operational amplifier U1 is a fixed DC bias voltage set at the output terminal of operational amplifier U1. However, when the bias voltage is introduced, the reference point of the output voltage of operational amplifier U1 changes from ground GND to the bias voltage Ubias.

[0107] Set a bias voltage Ubias at the output of operational amplifier U1 (replace GND on the output side with Ubias) to ensure that the output voltage of operational amplifier U1 is between 0 and Uin_compV, and does not exceed the voltage range of comparator U2 pin.

[0108] For example, in this solution, a reference voltage source can be sampled to provide the bias voltage. The reference voltage source can be a dedicated reference voltage chip, such as TL431, REF02, etc.

[0109] In terms of circuit connection, connect the reference ground of the output terminal of operational amplifier U1 (the pin originally connected to system ground) to the output terminal of this reference voltage source, so that the output voltage is referenced to this reference voltage.

[0110] In this scheme, the reference voltage of comparator U2 is the bias voltage Ubias set at the output of the operational amplifier.

[0111] refer to Figure 3As one possible implementation, the motor drive circuit is electrically connected to the DC bus, and the DC bus voltage is at least 800V. Correspondingly, the creepage distance between the first sampling resistor Ra and the second sampling resistor Rb at the PCB end (high-voltage circuit area) must meet the requirement of 3.8mm (requirements may vary between different manufacturers).

[0112] In this scheme, the resistance values ​​of the first sampling resistor Ra and the second sampling resistor Rb are determined according to the high and low voltage insulation impedance standards. The high and low voltage insulation impedance standards may include: for motors with a rated voltage of 1000V and those experiencing abnormalities, the insulation resistance (or sampling resistor) should not be less than 1MΩ.

[0113] Based on any of the aforementioned schemes, in one possible implementation scheme, the withstand voltage of the first sampling resistor and the second sampling resistor is greater than the maximum value of the phase voltage of the motor, and the resistance values ​​of the first sampling resistor and the second sampling resistor are set to be greater than 5MΩ.

[0114] For example, in this solution, if the rated voltage of the motor is 1000V, then the phase voltage is approximately 577V. Considering a safety margin of 1.5 to 2 times, the maximum phase voltage may reach 866 to 1154V.

[0115] Based on the determined maximum phase voltage, select a first sampling resistor Ra and a second sampling resistor Rb with a withstand voltage rating higher than this value. For example, if the calculated maximum phase voltage is 1000V, a first sampling resistor Ra and a second sampling resistor Rb with a withstand voltage of 1200V or 1500V can be selected.

[0116] In this solution, the high-resistance sampling resistor can be used as the insulation resistance between the high-voltage and low-voltage circuit areas. The high-resistance sampling resistor can prevent high voltage in the high-voltage circuit area from damaging the devices in the low-voltage circuit area, thereby eliminating the need for an additional isolation chip and reducing costs.

[0117] Based on the aforementioned sampling and processing unit including operational amplifier U1, comparator U2 and controller U3, in one possible implementation, comparator U2 outputs a PWM wave with a duty cycle of 0.5.

[0118] In this scheme, when the threshold of the comparator is set to the zero level of the differential signal (sine signal), the falling edge of the 0.5 duty cycle PWM wave corresponds exactly to the zero-crossing point of the sine signal. Since the zero-crossing point directly corresponds to the position reference value, it can avoid the difficulty in directly determining the time corresponding to the position reference value due to the duty cycle deviation, thus ensuring the speed and accuracy of calibration.

[0119] refer to Figure 3Based on any of the aforementioned schemes, in one possible implementation scheme, the self-calibration circuit includes a first sampling resistor Ra, a first sampling resistor Rb, an operational amplifier U1, a comparator U2, and a controller U3.

[0120] The sampling points of the motor drive circuit (the u-phase voltage output terminal and the v-phase voltage output terminal of the three-phase inverter) are electrically connected to the first input terminal and the second input terminal of the operational amplifier U1 through the first sampling resistor Ra and the second Rb, respectively.

[0121] The output of operational amplifier U1 is electrically connected to the first input of comparator U2, and the second input of comparator U2 is connected to a reference voltage.

[0122] The output of comparator U2 is electrically connected to controller U3, which is used to determine the initial angle of the motor.

[0123] In this scheme, the phase voltages of the u and v phases of the motor drive circuit are sampled through the first sampling resistor Ra and the second sampling resistor Rb, and used as the input of the (differential) operational amplifier U1.

[0124] The amplification factor of operational amplifier U1 is determined according to the following formula:

[0125] kop≤up / (2uin_comp)

[0126] At the output of the operational amplifier, replace GND with the reference voltage UbisV to ensure that the output voltage of operational amplifier U1 is within 0 to uin_comp.

[0127] The reference voltage of comparator U2 is set to Ubias. Comparator U2 outputs a PWM wave with a duty cycle of 0.5, and the output voltage of comparator U2 does not exceed the port voltage range of controller (MCU) U3.

[0128] The resistance values ​​of the first sampling resistor Ra and the second sampling resistor Rb are set to be greater than 5MΩ (determined based on the specified high and low voltage insulation impedance standards), and the withstand voltage is greater than up (usually 1000V). The first sampling resistor Ra and the second sampling resistor Rb can be implemented by multiple resistors connected in series.

[0129] The first sampling resistor Ra and the second sampling resistor Rb are set within an electrical insulation gap of 4.5 mm.

[0130] In this scheme, the controller U3 obtains the output angle of the rotary transformer (or eddy current sensor). When the controller U3 detects that the PWM wave output by the comparator U2 is at the falling edge, the controller U3 compares the deviation of 150° with the output angle of the rotary transformer (or eddy current sensor) and uses the difference as the initial angle of the motor, thus completing the self-calibration of the initial angle of the motor.

[0131] In this solution, sampling is achieved using a high-resistance sampling resistor. The sampling resistor is placed within the electrical isolation gap between the high-voltage and low-voltage circuit areas, saving space previously occupied by sampling resistors in the high-voltage region. Simultaneously, the high-resistance sampling resistor serves as insulation resistance between the high-voltage and low-voltage circuit areas. Isolation between these areas is achieved through the electrical isolation gap and the insulation resistance, thus eliminating the need for additional isolation chips and maintaining the same circuit functionality while reducing area and cost.

[0132] Example 2

[0133] This embodiment proposes a motor controller that stores the initial angle of the motor. The initial angle of the motor is determined by a calibration circuit based on any of the initial angles of the motor described in Embodiment 1. The implementation method and beneficial effects of the calibration circuit are the same as those described in Embodiment 1, and the specific details will not be repeated.

[0134] Example 3

[0135] This embodiment proposes a motor drive assembly, including a motor controller, a motor drive circuit, a sampling unit, and a signal processing unit.

[0136] The sampling unit is set in the electrical insulation gap between the high-voltage circuit area and the low-voltage circuit area. The high-voltage circuit area includes the motor drive circuit, and the low-voltage circuit area includes the motor controller and the signal processing unit. The electrical insulation gap is used for electrical isolation between the high-voltage circuit area and the low-voltage circuit area.

[0137] The sampling unit is connected between the sampling point of the motor drive circuit and the signal processing unit. The sampling unit is used to sample the phase voltage of two phases in the motor drive circuit.

[0138] The signal processing unit is connected to the sampling unit. The signal processing unit is used to compare the phase voltages of the two sampled phases and process them into square wave signals.

[0139] The motor controller is connected to the output of the signal processing unit, and the motor controller is configured to calibrate the initial angle of the motor based on the square wave signal.

[0140] In this solution, the motor controller can be specifically used to generate motor drive signals and calibrate the initial angle of the motor. The calibrated initial angle of the battery is stored in the motor controller.

[0141] In this solution, the corresponding content of the unit is the same as that described in Embodiment 1. The signal processing unit may include a differential operational amplifier circuit and a comparator circuit. The differential operational amplifier circuit and the comparator circuit are the same as those described in Embodiment 1, and the specific content will not be repeated.

[0142] Example 4

[0143] This embodiment proposes a vehicle including any of the motor initial angle self-calibration circuits described in Embodiment 1. The implementation method and beneficial effects of the circuit are the same as the corresponding content described in Embodiment 1, and the specific details will not be described in detail.

[0144] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A motor initial angle self-calibration circuit, characterized in that, Includes a sampling unit and a sampling processing unit; The sampling unit is located within the electrical insulation gap between the high-voltage circuit area and the low-voltage circuit area; The sampling unit is used to collect the phase voltage of the motor; The sampling processing unit is connected to the sampling unit, and the sampling processing unit is used to calibrate the initial angle of the motor based on the phase voltage.

2. The motor initial angle self-calibration circuit as described in claim 1, characterized in that, The sampling and processing unit is also used to: determine the position reference value of the phase position of the stator and rotor of the motor at a preset time using the square wave signal; The position measurement values ​​of the phase positions of the stator and rotor of the motor at the preset time are obtained, and the difference between the position reference value and the position measurement value is calibrated as the initial angle of the motor.

3. The motor initial angle self-calibration circuit as described in claim 2, characterized in that, The sampling unit includes a first sampling unit and a second sampling unit; the first sampling unit and the second sampling unit are used to sample the phase voltage of two phases in the motor drive circuit, respectively. The sampling processing unit includes a differential operational amplifier circuit, a comparator circuit, and a control unit; The first and second input terminals of the differential operational amplifier circuit are respectively connected to the output terminals of the first and second sampling units, and are used to perform differential processing on the sampled phase voltage signals of the two phases. The first input terminal of the comparator circuit is connected to the output terminal of the differential operational amplifier circuit, and the second input terminal of the comparator circuit is used to connect a reference voltage to process the signal output by the differential operational amplifier circuit into a square wave signal. The control unit is connected to the output of the comparison circuit. The control unit is used to identify the falling edge of the square wave signal, take the time when the falling edge is identified as the preset time, take the preset angle corresponding to the falling edge as the position reference value, and calculate the difference between the position reference value and the position measurement value as the initial angle of the motor.

4. The motor initial angle self-calibration circuit as described in claim 1, characterized in that, The sampling unit includes at least one first sampling resistor and at least one second sampling resistor; The first sampling resistor is connected in series between the first sampling point of the motor drive circuit and the first input terminal of the sampling processing unit. The second sampling resistor is connected in series at the second sampling point of the motor drive circuit and the second input terminal of the sampling processing unit; The first sampling point and the second sampling point are respectively set on any two different bridge arms of the motor drive circuit.

5. The motor initial angle self-calibration circuit as described in claim 3, characterized in that, The differential operational amplifier circuit includes an operational amplifier, the amplification factor of which is determined according to the following formula: kop≤up / (2uin_comp) In the formula, kop represents the amplification factor, up represents the maximum value of the phase voltage of the motor, and uin_comp represents the input voltage threshold of the comparator.

6. The motor initial angle self-calibration circuit as described in claim 3, characterized in that, The comparison circuit includes a comparator configured to output a PWM wave with a duty cycle of 0.

5.

7. The motor initial angle self-calibration circuit as described in claim 1, characterized in that, The motor drive circuit is electrically connected to the DC bus, and the voltage of the DC bus is at least 800V.

8. The motor initial angle self-calibration circuit as described in claim 1, characterized in that, The electrical insulation gap is at least 4.5 mm, and the electrical insulation gap is the air distance between the high-voltage circuit area and the low-voltage circuit area.

9. The motor initial angle self-calibration circuit as described in claim 4, characterized in that, The withstand voltage of the first sampling resistor and the second sampling resistor is greater than the maximum value of the phase voltage, and the resistance values ​​of the first sampling resistor and the second sampling resistor are at least greater than 5MΩ.

10. The motor initial angle self-calibration circuit as described in claim 4, characterized in that, On the circuit board corresponding to the high-voltage circuit area, the creepage distance between the first conductive part and the second conductive part is at least 3.8 mm; The first conductive part is one of the pins, pads, and traces corresponding to the first sampling resistor, and the second conductive part is one of the pins, pads, and traces corresponding to the second sampling resistor.

11. The motor initial angle self-calibration circuit as described in any one of claims 1 to 10, characterized in that, The phase voltage is any two phase voltages in the three-phase sinusoidal voltage; The motor drive circuit is configured to generate the three-phase sinusoidal voltage when the motor is idling at a preset speed.

12. A motor controller, characterized in that, The motor initial angle is stored, which is determined by the motor initial angle self-calibration circuit according to any one of claims 1 to 11.

13. A motor drive assembly, characterized in that, It includes a motor controller, a motor drive circuit, a sampling unit, and a signal processing unit; The sampling unit is disposed within an electrical insulation gap between the high-voltage circuit area and the low-voltage circuit area. The high-voltage circuit area includes the motor drive circuit, and the low-voltage circuit area includes the motor controller and the signal processing unit. The electrical insulation gap is used for electrical isolation between the high-voltage circuit area and the low-voltage circuit area. The sampling unit is connected between the sampling point of the motor drive circuit and the signal processing unit, and the sampling unit is used to sample the phase voltage of two phases in the motor drive circuit. The signal processing unit is connected to the sampling unit, and the signal processing unit is used to compare the phase voltages of the two sampled phases and process them into a square wave signal. The motor controller is connected to the output terminal of the signal processing unit, and the motor controller is configured to calibrate the initial angle of the motor based on the square wave signal.

14. A vehicle, characterized in that, Includes the motor initial angle self-calibration circuit as described in any one of claims 1 to 11.

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