Method and device for measuring voltage of direct current bus and terminal equipment

Abstract

The embodiment of the invention relates to the technical field of motor control, and discloses a direct current bus voltage measuring method and device and terminal equipment, and the method comprises the steps: converting the three-phase current of a motor controller into the actual output amplitude of the three-phase voltage according to the parameter information of a motor under a preset working condition; determining an actual theoretical value of the DC bus voltage according to the actual output amplitude of the three-phase voltage and the real-time duty ratio of the pulse width modulation signal; and judging whether a calibration condition is met based on the actual theoretical value of the direct-current bus voltage, and determining an actual measurement value of the direct-current bus voltage according to a judgment result. By applying the technical scheme of the invention, real-time automatic calibration can be realized in an electric drive full life cycle, the accuracy drift phenomenon of the voltage acquisition circuit is eliminated, the accuracy and stability of direct current bus voltage measurement are improved, and long-term reliable operation of a motor controller and a whole vehicle system is ensured.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to a method, apparatus, and terminal device for measuring DC bus voltage. Background Technology

[0002] In automotive and other terminal equipment, the motor controller is the core control unit of the motor system. Its core function is to receive commands from the upper level, combine the motor and equipment operating conditions, and achieve precise driving and efficient energy management of the drive motor through the power electronic conversion of the inverter and multiple closed-loop control of torque, speed and voltage. It is a key core component to ensure the power performance, operating efficiency and system safety of terminal equipment.

[0003] The accuracy of DC bus voltage acquisition in motor controllers directly determines the waveform accuracy of inverter output voltage / current, motor operating efficiency, and has a decisive impact on the reliability of safety protection functions such as overvoltage and undervoltage protection. Currently, the mainstream solution for DC bus voltage acquisition in motor controllers mainly relies on a pure hardware measurement architecture using Hall voltage sensors or voltage divider resistors paired with operational amplifiers. This type of hardware architecture, throughout the entire lifecycle of automotive and other end-device applications, is affected by factors such as strong EMC interference from the vehicle and component aging under complex operating conditions, resulting in continuous drift in acquisition accuracy. Furthermore, existing hardware solutions struggle to achieve dynamic online correction, causing voltage acquisition accuracy to gradually deteriorate over time, seriously threatening the long-term reliable operation of the motor controller and the entire vehicle system. Summary of the Invention

[0004] In view of the above problems, embodiments of the present invention provide a method, apparatus and terminal equipment for measuring DC bus voltage, which solves the problem of low accuracy in DC bus voltage measurement in the prior art.

[0005] According to one aspect of the present invention, a method for measuring DC bus voltage is provided. The method includes: acquiring the three-phase current of a motor controller under a set operating condition and the parameter information of the corresponding motor; determining the actual output amplitude of the three-phase voltage based on the parameter information and the three-phase current; determining the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of a pulse width modulation signal; determining whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage, and determining the actual measured value of the DC bus voltage based on the determination result.

[0006] According to another aspect of the present invention, a DC bus voltage measuring device is provided. The device includes: a data acquisition module for acquiring the three-phase current of a motor controller under a set operating condition and the corresponding motor parameter information; a data conversion module for determining the actual output amplitude of the three-phase voltage based on the parameter information and the three-phase current; a theoretical conversion module for determining the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal; and a calibration judgment module for judging whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage, and determining the actual measured value of the DC bus voltage based on the judgment result.

[0007] According to another aspect of the present invention, a terminal device is provided, including: a motor controller and a motor. The motor controller includes: a processor, a memory, a communication interface and a communication bus. The processor, the memory and the communication interface communicate with each other through the communication bus. The motor controller is used to drive the motor to run. The memory is used to store at least one executable instruction, which causes the processor to perform the operation of the DC bus voltage measurement method of the first aspect or any corresponding embodiment described above.

[0008] According to another aspect of the present invention, a computer program product is provided, including computer instructions for causing a computer to perform the operation of the DC bus voltage measurement method of the first aspect or any corresponding embodiment thereof.

[0009] The DC bus voltage measurement method provided in this invention acquires the three-phase current of the motor controller and the parameter information of the motor under preset operating conditions. Based on the parameter information, the three-phase current is gradually converted into the actual output amplitude of the three-phase voltage. Based on the real-time duty cycle of the pulse width modulation signal, the actual output amplitude of the three-phase voltage is converted into the actual theoretical value of the DC bus voltage. Based on the actual theoretical value of the three-phase voltage, it is determined whether the calibration conditions are met, and the actual measured value of the DC bus voltage is determined according to the judgment result. This method can achieve real-time automatic calibration throughout the entire life cycle of the electric drive, eliminate the accuracy drift phenomenon of the voltage acquisition circuit, improve the accuracy and stability of DC bus voltage measurement, and ensure the long-term reliable operation of the motor controller and the whole vehicle system. At the same time, it achieves automatic calibration without the aid of other equipment or controllers, which can reduce the accuracy requirements of the hardware measurement architecture and reduce costs.

[0010] The above description is merely an overview of the technical solutions of the embodiments of the present invention. In order to better understand the technical means of the embodiments of the present invention and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0011] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram illustrating an application scenario of an embodiment of the present invention is shown; Figure 2 A flowchart illustrating a first embodiment of the DC bus voltage measurement method provided by the present invention is shown. Figure 3 A flowchart illustrating a second embodiment of the DC bus voltage measurement method provided by the present invention is shown. Figure 4 A schematic diagram of the overall process of the DC bus voltage measurement method provided by the present invention is shown; Figure 5 A flowchart illustrating a third embodiment of the DC bus voltage measurement method provided by the present invention is shown. Figure 6 A schematic diagram of the structure of a first embodiment of the DC bus voltage measuring device provided by the present invention is shown; Figure 7 A schematic diagram of the structure of a motor controller in an embodiment of the terminal device provided by the present invention is shown. Detailed Implementation

[0012] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0013] As an optional application scenario of this invention, such as Figure 1 As shown, a motor controller 101 and a motor 102 are deployed on the terminal equipment 100, such as vehicles and industrial equipment. Taking a vehicle as an example of the terminal equipment 100, the motor controller 101 acts as a bridge between the vehicle controller and the motor 102. It receives acceleration / deceleration and torque / speed target commands (such as the signal from the driver pressing the accelerator pedal) issued by the VCU, combines them with the current operating conditions (vehicle speed, battery status) and converts them into control signals that the motor can execute. By controlling the IGBT switching state of the inverter, it inverts the DC power from the power battery into three-phase AC power to drive the motor to output matching power. During the driving process, the motor controller 101 collects data such as the three-phase current of the motor, rotor position, and DC bus voltage to realize multiple control functions such as torque closed-loop, speed closed-loop, and voltage closed-loop.

[0014] The accuracy of DC bus voltage acquisition in the motor controller directly determines the waveform accuracy of the inverter output voltage / current, motor operating efficiency, and has a decisive impact on the reliability of safety protection functions such as overvoltage and undervoltage protection. Inaccurate voltage acquisition can lead to increased inverter output harmonic distortion, decreased motor efficiency, and even misjudgment of overvoltage / undervoltage protection thresholds, causing unexpected system shutdowns or component damage. Using a pure hardware measurement architecture with Hall voltage sensors or voltage divider resistors and operational amplifiers to measure DC bus voltage not only introduces single-point-of-failure risks due to additional components, increasing the overall system failure probability, but also results in continuous accuracy drift throughout the entire lifecycle of automotive and other terminal equipment due to strong EMC interference (such as high-voltage wiring harness coupling interference and radiation interference from automotive electrical appliances) and component aging under complex operating conditions (such as resistance drift, operational amplifier temperature drift, and Hall element core loss). Furthermore, existing hardware solutions struggle to achieve dynamic online correction, causing voltage acquisition accuracy to gradually deteriorate over time, seriously threatening the long-term reliable operation of the motor controller and the entire vehicle system.

[0015] Therefore, this invention provides a method for measuring DC bus voltage. By gradually converting the measured three-phase current into the actual theoretical value of DC bus voltage, and calibrating based on the actual theoretical value of DC bus voltage and the initial measurement value collected by the voltage acquisition circuit, the method aims to eliminate accuracy drift and improve the accuracy and stability of DC bus voltage measurement.

[0016] Figure 2 A flowchart of a first embodiment of the method for measuring DC bus voltage according to the present invention is shown, the method being executed by the aforementioned motor controller. Figure 2 As shown, the method includes the following steps: Step S201: Obtain the three-phase current of the motor controller under the set operating conditions, and the corresponding motor parameter information.

[0017] In this embodiment of the invention, to ensure the reliability of the calibration benchmark, the validity of the data, and the accuracy of the final measured DC target voltage, analysis and calibration are performed under stable operating conditions. This avoids data distortion under unstable operating conditions that could lead to the failure of the calibration benchmark and the use of incorrect data to correct incorrect data. However, this is not a limitation. Stable operating conditions refer to a state in which the motor controller and motor operate with minimal speed fluctuations, stable load, and no sudden changes in electrical parameters. This state ensures the validity of data such as three-phase current and PWM real-time duty cycle.

[0018] Taking a stable operating condition as an example, the three-phase current collected by the three-phase current sensor is obtained. , , In practical operation, any two-phase current can be collected, for example... and The complete three-phase current can be calculated based on the characteristics of the three-phase current. , , Simultaneously, the inverter modulates the DC bus voltage using PWM (Pulse Width Modulation) signal. Inverting to three-phase current , , The DC bus voltage is visible. It is related to the three-phase current and the pulse width modulation signal. Therefore, the real-time duty cycle of the PWM is obtained during the calibration of the DC bus voltage.

[0019] Furthermore, the conversion of three-phase current into three-phase voltage requires information about the motor's parameters. Therefore, obtaining the motor's parameters under stable operating conditions is crucial, including both inherent and operational parameters. Inherent parameters include the direct-axis inductance of the windings. and cross-axis inductance Stator resistance Rotor permanent magnet flux linkage parameters Operating parameters include: rotor electrical angle Electric angular velocity The inherent parameters of the motor are measured on a test bench beforehand and stored in the system.

[0020] Step S202: Determine the actual output amplitude of the three-phase voltage based on parameter information and three-phase current.

[0021] In this embodiment of the invention, the three-phase current ( , , ), three-phase voltage ( , , ) and DC bus voltage ( The three core physical quantities of energy conversion and control in a motor controller are the inverter's power electronic conversion, the motor's electromagnetic induction laws, and closed-loop control algorithms, forming a progressive relationship of energy source, control medium, and execution output. Among them, the DC bus voltage... It is the input electrical energy carrier of the motor controller, three-phase voltage. , , An inverter is an energy converter that transforms direct current (DC) into alternating current (AC), and three-phase current... , , This is the manifestation of the motor absorbing electrical energy and converting it into mechanical energy; it can be seen that the three-phase current... , , The magnitude of the reaction effect on the DC bus voltage The stability of the three-phase voltage can be derived from the actual measured three-phase current, and then the actual output amplitude of the DC bus voltage can be deduced from this. This serves as the basis for calibration.

[0022] In some optional implementations, the present invention constructs a conversion process for three-phase current, dq-axis current, dq-axis voltage, and three-phase voltage. This is based on the core logic of motor vector control (FOC). Through coordinate system transformation, physical quantity mapping, and accuracy traceability, it solves the problems of high complexity in AC motor control, strong parameter coupling, and difficulty in directly measuring the actual voltage, thereby obtaining the actual output amplitude of the three-phase voltage. .

[0023] Step S203: Determine the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal.

[0024] In this embodiment of the invention, based on the theoretical foundation of the entire FOC vector control process, the theoretical three-phase output voltage within any PWM switching cycle is... and DC bus voltage There exists a precise and unique mathematical relationship between the modulation signal and the DC bus voltage, therefore, based on the theoretical foundation of the SVPWM model, the DC bus voltage is constructed. and three-phase output voltage Theoretical amplitude constraint relationship between them:

[0025] in, This represents the duty cycle of the carrier wave corresponding to the PWM, ranging from 0 to 1. Therefore, the actual output amplitude of the three-phase voltage is obtained. Then, according to the above theoretical amplitude constraint relationship, based on the actual output amplitude of the three-phase voltage... and real-time duty cycle The actual theoretical value of DC bus voltage can be derived by reverse calculation. This serves as the basis for calibration.

[0026] Step S204: Determine whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage, and determine the actual measured value of the DC bus voltage based on the determination result.

[0027] In this embodiment of the invention, during normal operation, the DC bus voltage of the motor controller is still acquired in real time using a voltage acquisition circuit with a hardware architecture such as a deployed Hall voltage sensor or a voltage divider resistor plus an operational amplifier, and this is used as the initial measurement value before calibration. The actual theoretical value of the DC bus voltage The initial measured value of the DC bus voltage was obtained by reverse deduction based on fundamental theory. The voltage is actually acquired by the voltage acquisition circuit. If the accuracy of the voltage acquisition circuit drifts during use, the actual theoretical value will be affected. and initial measurement value There is a certain deviation between them, indicating that the acquisition accuracy of the circuit is insufficient and calibration is required; if the actual theoretical value and initial measurement value If there is no deviation or the deviation is small, it proves that the acquisition accuracy of the circuit is sufficient and no calibration is required.

[0028] Therefore, the embodiments of the present invention are based on the actual theoretical value of the DC bus voltage. and initial measurement value Determine if the calibration conditions are met. If the calibration conditions are not met, directly output the initial measurement value of the voltage acquisition circuit. This is used as the actual measured value of the DC bus voltage. If the calibration conditions are met, the initial measurement value will be used. Based on the actual theoretical value Based on this, the gain function of the voltage acquisition circuit is calibrated to obtain the actual measured value of the calibrated DC bus voltage. .

[0029] The DC bus voltage measurement method provided in this invention acquires the three-phase current of the motor controller and the parameter information of the motor under preset operating conditions. Based on the parameter information, the three-phase current is gradually converted into the actual output amplitude of the three-phase voltage. Based on the real-time duty cycle of the pulse width modulation signal, the actual output amplitude of the three-phase voltage is converted into the actual theoretical value of the DC bus voltage. Based on the actual theoretical value of the three-phase voltage, it is determined whether the calibration conditions are met, and the actual measured value of the DC bus voltage is determined according to the judgment result. This method can achieve real-time automatic calibration throughout the entire life cycle of the electric drive, eliminate the accuracy drift phenomenon of the voltage acquisition circuit, improve the accuracy and stability of DC bus voltage measurement, and ensure the long-term reliable operation of the motor controller and the whole vehicle system. At the same time, it achieves automatic calibration without the aid of other equipment or controllers, which can reduce the accuracy requirements of the hardware measurement architecture and reduce costs.

[0030] Figure 3 A flowchart of a second embodiment of the method for measuring DC bus voltage according to the present invention is shown, the method being executed by the aforementioned motor controller. Figure 3 As shown, the method includes the following steps: Step S301: Continuously acquire the three-phase current of the motor controller and the rotor mechanical angular velocity of the motor according to the preset sampling period, convert the three-phase current into direct-axis current and quadrature-axis current in the dq coordinate system, and convert the rotor mechanical angular velocity into rotor electrical angular velocity.

[0031] In this embodiment of the invention, during motor operation, the three-phase current collected by the three-phase current sensor is continuously acquired according to a preset sampling period. , , And the rotor mechanical angular velocity of the motor. Simultaneously, the three-phase current will be collected in real time. , , The direct-axis current in the dq coordinate system is obtained by successively applying the Clarke transformation and the Park transformation. and cross-axis current Converting the mechanical angular velocity of the motor rotor into the electrical angular velocity of the rotor. This reflects the operating status of the motor.

[0032] Step S302: Determine whether the motor is in a stable operating condition based on the rotor electric angular velocity, direct-axis current, and quadrature-axis current.

[0033] In some optional implementations, step S302 above includes: Step S3021: Determine the average speed and standard deviation of the rotational speed based on the rotor electric angular velocity within the preset sampling period, and determine the rotational speed fluctuation rate based on the average speed and standard deviation of the rotational speed.

[0034] In this embodiment of the invention, multiple rotor electrical angular velocities can be obtained within the sampling period. Multiple rotor electric angular velocities Calculate the average to obtain the average rotational speed. Then, based on multiple rotor electric angular velocities and average speed Calculate the standard deviation of rotational speed This reflects the degree of dispersion in rotational speed fluctuations.

[0035] Furthermore, based on the average rotational speed and standard deviation of rotational speed The formula for calculating the speed fluctuation rate is shown below:

[0036] Step S3022: Determine the average value and standard deviation of the cross-axis current based on the cross-axis current within the preset sampling period, and determine the cross-axis current fluctuation rate based on the average value and standard deviation of the cross-axis current.

[0037] In this embodiment of the invention, the quadrature-axis current... Directly reflecting the motor load, its stability is a core indicator for determining operational stability. Multiple quadrature-axis currents can be obtained within the sampling period. Multiple quadrature axis currents Calculate the average to obtain the average rotational speed. Then, based on multiple quadrature axis currents and average speed Calculate the standard deviation of quadrature axis current This reflects the degree of dispersion in rotational speed fluctuations.

[0038] Furthermore, based on the average rotational speed and cross-axis current standard deviation The formula for calculating the quadrature-axis current ripple rate is shown below:

[0039] Step S3023: If the rotor electric angular velocity is greater than the second preset threshold, the speed fluctuation rate is less than the third preset threshold, the quadrature axis current fluctuation rate is less than the fourth preset threshold, and the absolute value of the direct axis current is less than the fifth preset threshold within a consecutive preset number of preset sampling periods, then the motor is determined to be in a stable operating condition; otherwise, it is determined to be not in a stable operating condition.

[0040] Specifically, in this embodiment of the invention, firstly, using a preset sampling period as the unit, it is determined whether the following conditions are met simultaneously within the preset sampling period: ① rotor electrical angular velocity Greater than the second preset threshold The conditions are: ① the rotational speed fluctuation rate is less than the third preset threshold; ② the quadrature-axis current fluctuation rate is less than the fourth preset threshold; ③ the absolute value of the direct-axis current is less than the fifth preset threshold. Among these, the second preset threshold... It can be flexibly configured to ensure that the back electromotive force accounts for a certain percentage of the DC bus voltage. At least 10% is acceptable. The fifth preset threshold can be set to 0 or close to 0. The third and fourth preset thresholds are determined based on stable operating conditions and are not limited here.

[0041] Secondly, if all four conditions are met simultaneously within a preset sampling period, it is further determined whether conditions ⑤ are met for a consecutive preset number of preset periods, thereby determining whether the four conditions are continuously met throughout the duration. Figure 4 As shown, if all four conditions are met continuously within the specified time period, then conditions ①-⑤ are all satisfied, and the system is considered to be in a stable operating condition. If at least one condition is not met within the preset sampling period, or if the condition is not met continuously within the preset period, the system is considered to be not in a stable operating condition.

[0042] Step S303: Obtain the three-phase current of the motor controller under stable operating conditions, and the corresponding motor parameter information. For details, please refer to [link to relevant documentation]. Figure 2 Step S201 of the illustrated embodiment will not be described again here.

[0043] Step S304: Determine the actual output amplitude of the three-phase voltage based on the parameter information and the three-phase current.

[0044] Specifically, step S304 includes: Step S3041: Perform Clarke transformation on the three-phase current to obtain... Two-phase stationary coordinate system shaft current and Shaft current, and based on rotor electrical angle pairs shaft current and The Park transformation is performed on the axis currents to obtain the direct-axis currents and quadrature-axis currents in the dq coordinate system.

[0045] In the embodiments of the present invention, such as Figure 4 As shown, the three-phase current collected under stable operating conditions... , , Through Clarke transform, we obtain Two-phase stationary coordinate system shaft current and shaft current Then shaft current and shaft current The direct-axis current in the dq coordinate system is obtained through the Park transformation. and cross-axis current The Clarke transform formula and the Park transform formula are shown below:

[0046]

[0047] in, The rotor electrical angle of the motor.

[0048] Step S3042: Based on the electric angular velocity, direct-axis inductance, quadrature-axis inductance, stator resistance, and rotor permanent magnet flux linkage parameters, the direct-axis current and quadrature-axis current are converted into direct-axis voltage and quadrature-axis voltage.

[0049] In the embodiments of the present invention, such as Figure 4 As shown, based on the electric angular velocity of the motor under steady-state operating conditions... Inherent parameters of the motor: direct-axis inductance quadrature axis inductance Stator resistance Rotor permanent magnet flux linkage parameters Direct-axis current and cross-axis current Convert to direct-axis voltage and quadrature axis voltage The conversion formula is shown below:

[0050]

[0051] Step S3043: Perform an inverse Parker transformation on the direct-axis voltage and quadrature-axis voltage based on the rotor electrical angle to obtain... Two-phase stationary coordinate system shaft voltage and shaft voltage, and will shaft voltage and The shaft voltages are vector synthesized to obtain the actual output amplitude of the three-phase voltages.

[0052] In this embodiment of the invention, the direct-axis voltage in the dq coordinate system is transformed by the inverse Park transformation. and quadrature axis voltage Transform into Two-phase stationary coordinate system shaft voltage and shaft voltage The inverse Park change formula is shown below:

[0053] Furthermore, shaft voltage and shaft voltage Vector synthesis is performed to obtain the actual output amplitude of the three-phase voltage. The vector relationship for vector composition is shown below:

[0054] Step S305: Determine the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal.

[0055] Specifically, step S305 includes: Step S3051: Determine the theoretical amplitude constraint relationship between the three-phase voltage peak value, the duty cycle of the pulse width modulation signal, and the DC bus voltage.

[0056] In this embodiment of the invention, the DC bus voltage is pre-constructed. and three-phase output voltage Theoretical amplitude constraint relationship between them:

[0057] Step S3052: Calculate the ratio of the actual output amplitude of the three-phase voltage to the real-time duty cycle to obtain the actual theoretical value of the DC bus voltage.

[0058] In this embodiment of the invention, the actual output amplitude of the three-phase voltage is derived step by step based on the three-phase current. Then, based on the above theoretical amplitude constraint relationship, the actual output amplitude of the three-phase voltage is calculated. Compared with real-time duty cycle The ratio of these values ​​is used to obtain the actual theoretical value of the DC bus voltage. The calculation formula is as follows:

[0059] Step S306: Determine whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage, and determine the actual measured value of the DC bus voltage based on the determination result. For details, please refer to [link to relevant documentation]. Figure 2 Step S204 of the illustrated embodiment will not be described again here.

[0060] The DC bus voltage measurement method provided in this invention acquires the three-phase current of the motor controller and the parameter information of the motor under preset operating conditions. Based on the parameter information, the three-phase current is gradually converted into the actual output amplitude of the three-phase voltage. Based on the real-time duty cycle of the pulse width modulation signal, the actual output amplitude of the three-phase voltage is converted into the actual theoretical value of the DC bus voltage. Based on the actual theoretical value of the three-phase voltage, it is determined whether the calibration conditions are met, and the actual measured value of the DC bus voltage is determined according to the judgment result. This method can achieve real-time automatic calibration throughout the entire life cycle of the electric drive, eliminate the accuracy drift phenomenon of the voltage acquisition circuit, improve the accuracy and stability of DC bus voltage measurement, and ensure the long-term reliable operation of the motor controller and the whole vehicle system. At the same time, it achieves automatic calibration without the aid of other equipment or controllers, which can reduce the accuracy requirements of the hardware measurement architecture and reduce costs.

[0061] Figure 5 A flowchart of a third embodiment of the method for measuring DC bus voltage according to the present invention is shown, which is executed by the aforementioned motor controller. Figure 5 As shown, the method includes the following steps: Step S501: Obtain the three-phase current of the motor controller under the set operating conditions, and the corresponding motor parameter information. For details, please refer to [link to relevant documentation]. Figure 3 Step S303 of the illustrated embodiment will not be described again here.

[0062] Step S502: Determine the actual output amplitude of the three-phase voltage based on the parameter information and three-phase current. For details, please refer to [link to relevant documentation]. Figure 3 Step S304 of the illustrated embodiment will not be described again here.

[0063] Step S503: Determine the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal. For details, please refer to [link to relevant documentation]. Figure 3 Step S305 of the illustrated embodiment will not be described again here.

[0064] Step S504: Determine whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage, and determine the actual measured value of the DC bus voltage based on the determination result.

[0065] Specifically, step S504 includes: Step S5041: Calculate the voltage difference between the actual theoretical value and the initial measurement value of the voltage acquisition circuit, and determine whether the absolute value of the voltage difference is greater than the first preset threshold.

[0066] In this embodiment of the invention, if the DC bus voltage obtains the actual theoretical value... and initial measurement value There is a certain deviation between them, indicating that the acquisition accuracy of the circuit is insufficient and calibration is required; if the actual theoretical value and initial measurement value If there is no deviation or the deviation is small, it proves that the acquisition accuracy of the circuit is sufficient and no calibration is required. Figure 4 As shown, calculate the actual theoretical value. and initial measurement value voltage difference between ,Right now And determine the voltage difference. Whether it exceeds the fifth preset threshold, such as 5V, but is not limited to this.

[0067] Step S5042: If the absolute value of the voltage difference is greater than the first preset threshold, the number of deviations is accumulated, and it is determined whether the number of deviations is greater than the preset number.

[0068] In this embodiment of the invention, if Then for the number of deviations Accumulate the deviations (starting from 0), and simultaneously determine the number of deviations. Is it greater than the preset number of times, for example? However, this is not the limitation. Embodiments of the present invention address the deviation count... Accumulation can filter out occasional voltage difference exceeding the standard caused by factors such as instantaneous interference from sensors, avoid triggering subsequent control actions by a single abnormality, effectively improve the accuracy and anti-interference capability of voltage monitoring and judgment, ensure the stability of equipment or system operation, and prevent problems such as increased energy consumption and equipment damage caused by misoperation.

[0069] In step S5043, if the number of deviations is greater than the second preset number, the calibration condition is determined to be met; otherwise, the calibration condition is determined not to be met.

[0070] In this embodiment of the invention, if the deviation number If the number of calibration attempts exceeds the preset limit, the calibration conditions are met. In this case, the voltage acquisition circuit exhibits accuracy drift and requires calibration. Otherwise, the calibration conditions are not met, meaning calibration is not required.

[0071] In step S5044, if the calibration conditions are not met, the initial measurement value of the voltage acquisition circuit is used as the actual measurement value of the DC bus voltage.

[0072] In this embodiment of the invention, when the calibration conditions are not met, there is no need to calibrate the voltage acquisition circuit; that is, the acquisition accuracy of the voltage acquisition circuit is assumed to be sufficient, and therefore the initial measurement value of the voltage acquisition circuit is directly output. This is used as the final actual measured value of the DC bus voltage. .

[0073] In step S5045, if the calibration conditions are met, the gain function relationship of the voltage acquisition circuit is calibrated, and the actual measured value of the DC bus voltage is determined based on the calibrated gain function relationship.

[0074] In this embodiment of the invention, if the calibration conditions are met, the gain function of the voltage acquisition circuit is calibrated, so that the calibration is achieved entirely through software algorithms without increasing any cost. It can even reduce the cost of the sensor, and the calibration accuracy is very high, effectively supporting the realization of various functions and performance of the controller.

[0075] In some optional implementations, step S5045 above includes: Step a1: Obtain the actual output value and initial measurement value of the voltage acquisition circuit under multiple set operating conditions, and fit the actual output value and initial measurement value to obtain the first gain function relationship of the voltage acquisition circuit. The first gain function relationship includes the sampling circuit gain coefficient and the sampling circuit offset.

[0076] In this embodiment of the invention, the initial measured values ​​of the continuous three-phase current and the DC bus voltage are... The parameters were collected, and the actual theoretical value of the DC bus voltage was obtained through step-by-step conversion. Simultaneously, the actual output value of the voltage acquisition circuit is continuously acquired. The actual output value This is the original value that has not been adjusted according to the gain of the voltage acquisition circuit itself. Therefore, this embodiment of the invention uses the actual output value of the voltage acquisition circuit. Initial measurement of DC bus voltage By performing linear fitting, the first gain function relationship of the voltage acquisition circuit is obtained, as shown below:

[0077] in, The gain coefficient of the sampling circuit. This represents the sampling circuit offset. At this point, the first gain function expression includes the accuracy drift caused by EMC interference / device aging and other issues during the voltage acquisition circuit's entire lifespan.

[0078] Step a2: Calculate the voltage difference between the actual theoretical value and the initial measured value for each group, and obtain the gain compensation function relationship based on the voltage difference and the gain coefficient of the sampling circuit.

[0079] In this embodiment of the invention, the actual theoretical value of the DC bus voltage is... Compared with the initial measurement value voltage difference between Corresponding to accuracy drift, therefore based on the sampling circuit gain coefficient , to the actual theoretical value Compared with the initial measurement value voltage difference between The gain compensation function relationship for the voltage sampling circuit is shown below:

[0080] Step a3: Combine the first gain function relationship and the gain compensation function relationship to obtain the second gain function relationship.

[0081] In this embodiment of the invention, the first gain function relationship includes the error caused by accuracy drift, while the gain compensation function relationship represents the error correction process. Therefore, merging the first gain function relationship and the gain compensation function relationship is equivalent to eliminating the error present in the first gain function relationship, thereby obtaining the accurate second gain function relationship, which is shown below:

[0082] Step a4: Adjust the actual output value of the voltage acquisition circuit according to the second gain function relationship, and determine the actual measured value of the DC bus voltage based on the adjusted actual output value.

[0083] In this embodiment of the invention, the second gain function represents the calibrated voltage acquisition circuit. However, the hardware structure of the voltage acquisition circuit remains unchanged; instead, it is corrected through a software algorithm. That is, the actual output value of the voltage acquisition circuit is determined based on the second gain function. Adjustments are made to obtain the adjusted actual output value. Based on this, according to the second gain function relationship and the adjusted actual output value... The actual measured value of the DC bus voltage was derived by reverse calculation. The reverse formula is shown below:

[0084] After entering the next calibration cycle The adjustment and compensation process continues. Therefore, the embodiments of the present invention can perform automatic calibration during the motor stabilization process without the aid of any other equipment or controller, and operate in a self-closed loop within the controller; it is automatically executed periodically throughout the entire product life cycle, and can perform reasonable compensation regardless of whether the sensor detection signal is positively or negatively biased, thereby compensating for parameter changes caused by aging and temperature drift.

[0085] The DC bus voltage measurement method provided in this invention acquires the three-phase current of the motor controller and the parameter information of the motor under preset operating conditions. Based on the parameter information, the three-phase current is gradually converted into the actual output amplitude of the three-phase voltage. Based on the real-time duty cycle of the pulse width modulation signal, the actual output amplitude of the three-phase voltage is converted into the actual theoretical value of the DC bus voltage. Based on the actual theoretical value of the three-phase voltage, it is determined whether the calibration conditions are met, and the actual measured value of the DC bus voltage is determined according to the judgment result. This method can achieve real-time automatic calibration throughout the entire life cycle of the electric drive, eliminate the accuracy drift phenomenon of the voltage acquisition circuit, improve the accuracy and stability of DC bus voltage measurement, and ensure the long-term reliable operation of the motor controller and the whole vehicle system. At the same time, it achieves automatic calibration without the aid of other equipment or controllers, which can reduce the accuracy requirements of the hardware measurement architecture and reduce costs.

[0086] Figure 6 A schematic diagram of an embodiment of the DC bus voltage measuring device of the present invention is shown. Figure 6 As shown, the device 600 includes: The data acquisition module 601 is used to acquire the three-phase current of the motor controller under the set operating conditions and the corresponding motor parameter information.

[0087] The data conversion module 602 is used to determine the actual output amplitude of the three-phase voltage based on parameter information and three-phase current.

[0088] The theoretical conversion module 603 is used to determine the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal.

[0089] The calibration judgment module 604 is used to determine whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage, and to determine the actual measured value of the DC bus voltage based on the judgment result.

[0090] In some optional implementations, the calibration determination module 604 includes: The difference calculation unit is used to calculate the voltage difference between the actual theoretical value and the initial measurement value of the voltage acquisition circuit, and to determine whether the absolute value of the voltage difference is greater than a first preset threshold.

[0091] The number update unit is used to accumulate the number of deviations if the absolute value of the voltage difference is greater than the first preset threshold, and to determine whether the number of deviations is greater than the preset number.

[0092] The calibration judgment unit is used to determine whether the calibration conditions are met if the number of deviations is greater than a preset number, otherwise it determines that the calibration conditions are not met.

[0093] The result output unit is used to take the initial measurement value of the voltage acquisition circuit as the actual measurement value of the DC bus voltage if the calibration conditions are not met.

[0094] The circuit calibration unit is used to calibrate the gain function relationship of the voltage acquisition circuit if the calibration conditions are met, and to determine the actual measured value of the DC bus voltage based on the calibrated gain function relationship.

[0095] In some alternative implementations, the circuit calibration unit includes: The first function determines the sub-unit, which is used to obtain the actual output value and initial measurement value of the voltage acquisition circuit under multiple set operating conditions, and to fit the first gain function relationship of the voltage acquisition circuit based on the actual output value and the initial measurement value. The first gain function relationship includes the sampling circuit gain coefficient and the sampling circuit offset. The second function determines the sub-unit, which is used to calculate the voltage difference between each group of actual theoretical values ​​and initial measured values, and obtains the gain compensation function relationship based on the voltage difference and the sampling circuit gain coefficient.

[0096] The third function determines the sub-unit, which is used to combine the first gain function relationship and the gain compensation function relationship to obtain the second gain function relationship.

[0097] The actual voltage determination subunit is used to adjust the actual output value of the voltage acquisition circuit according to the second gain function relationship, and to determine the actual measured value of the DC bus voltage based on the adjusted actual output value.

[0098] In some optional embodiments, the apparatus further includes: a working condition determination module, which includes: The data acquisition unit is used to continuously acquire the three-phase current of the motor controller and the rotor mechanical angular velocity of the motor according to a preset sampling period, convert the three-phase current into direct-axis current and quadrature-axis current in the dq coordinate system, and convert the rotor mechanical angular velocity into rotor electrical angular velocity.

[0099] The operating condition judgment unit is used to determine whether the motor is in a stable operating condition based on the rotor electric angular velocity, direct axis current and quadrature axis current.

[0100] In some optional implementations, the operating condition determination unit includes: The first parameter calculation subunit is used to determine the average speed and standard deviation of the speed based on the rotor electric angular velocity within a preset sampling period, and to determine the speed fluctuation rate based on the average speed and standard deviation of the speed.

[0101] The second parameter calculation subunit is used to determine the average value and standard deviation of the cross-axis current based on the cross-axis current within a preset sampling period, and to determine the cross-axis current fluctuation rate based on the average value and standard deviation of the cross-axis current.

[0102] The condition judgment subunit is used to determine that the motor is in a stable operating condition if the rotor electric angular velocity is greater than the first preset threshold, the speed fluctuation rate is less than the third preset threshold, the quadrature axis current fluctuation rate is less than the fourth preset threshold, and the absolute value of the direct axis current is less than the fifth preset threshold within a consecutive preset number of preset sampling periods; otherwise, it is determined that the motor is not in a stable operating condition.

[0103] In some alternative implementations, the data conversion module 602 includes: The current conversion unit is used to perform Clarke transformation on the three-phase current to obtain... Two-phase stationary coordinate system shaft current and Shaft current, and based on rotor electrical angle pairs shaft current and The Park transformation is performed on the axis currents to obtain the direct-axis currents and quadrature-axis currents in the dq coordinate system.

[0104] The first voltage conversion unit is used to convert direct-axis current and quadrature-axis current into direct-axis voltage and quadrature-axis voltage based on rotor electric angular velocity, direct-axis inductance, quadrature-axis inductance, stator resistance and rotor permanent magnet flux linkage parameters.

[0105] The second voltage conversion unit is used to perform inverse Park transformation on the direct-axis voltage and quadrature-axis voltage based on the rotor electrical angle, to obtain... Two-phase stationary coordinate system shaft voltage and shaft voltage, and will shaft voltage and The shaft voltages are vector synthesized to obtain the actual output amplitude of the three-phase voltages.

[0106] In some alternative implementations, the theory conversion module 603 includes: The constraint relationship determination unit is used to determine the theoretical amplitude constraint relationship between the three-phase voltage peak value, the duty cycle of the pulse width modulation signal, and the DC bus voltage. The theoretical amplitude constraint relationship is that the three-phase voltage peak value is equal to the product of the DC bus voltage and the real-time duty cycle.

[0107] The voltage conversion unit is used to calculate the ratio of the actual output amplitude of the three-phase voltage to the real-time duty cycle, so as to obtain the actual theoretical value of the DC bus voltage.

[0108] Figure 7 The diagram shows a schematic of the motor controller in the terminal device provided by an embodiment of the present invention. The specific embodiments of the present invention do not limit the specific implementation of the vehicle.

[0109] like Figure 7 As shown, the motor controller may include: a processor 702, a communications interface 704, a memory 706, and a communications bus 708.

[0110] The processor 702, communication interface 704, and memory 706 communicate with each other via communication bus 708. Communication interface 704 is used to communicate with other network elements, such as clients or other servers. Processor 702 executes program 710, specifically performing the relevant steps in the above-described embodiment of the method for measuring DC bus voltage.

[0111] Specifically, program 710 may include program code, which includes computer-executable instructions.

[0112] The processor 702 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The vehicle may include one or more processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0113] Memory 706 is used to store program 710. Memory 706 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0114] Specifically, program 710 can be called by processor 702 to cause the vehicle to execute the above-mentioned commands. Figure 2 , Figure 3 or Figure 4The operation of the DC bus voltage measurement method shown.

[0115] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the DC bus voltage measurement method shown in the above embodiments is implemented.

[0116] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0117] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Furthermore, the embodiments of this invention are not directed to any particular programming language.

[0118] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. Similarly, for the sake of brevity and to aid in understanding one or more aspects of the invention, in the description of exemplary embodiments of the invention above, various features of the embodiments are sometimes grouped together in a single embodiment, figure, or description thereof. The claims, which follow the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0119] Those skilled in the art will understand that the modules in the device of the embodiment can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiment can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components, except that at least some of such features and / or processes or units are mutually exclusive.

[0120] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for measuring DC bus voltage, characterized in that, The method includes: Obtain the three-phase current of the motor controller under the set operating conditions, and the corresponding motor parameter information; The actual output amplitude of the three-phase voltage is determined based on the parameter information and the three-phase current. The actual theoretical value of the DC bus voltage is determined based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal. Based on the actual theoretical value of the DC bus voltage, determine whether the calibration conditions are met, and determine the actual measured value of the DC bus voltage based on the determination result.

2. The method according to claim 1, characterized in that, The step of determining the actual measured value of the DC bus voltage based on the judgment result includes: If the calibration conditions are not met, the initial measurement value of the voltage acquisition circuit shall be used as the actual measurement value of the DC bus voltage. If the calibration conditions are met, the gain function of the voltage acquisition circuit is calibrated, and the actual measured value of the DC bus voltage is determined based on the calibrated gain function.

3. The method according to claim 2, characterized in that, The calibration of the gain function relationship of the voltage acquisition circuit, and the determination of the actual measured value of the DC bus voltage based on the calibrated gain function relationship, includes: The actual output value and initial measurement value of the voltage acquisition circuit under the set operating conditions are obtained in multiple sets. The first gain function relationship of the voltage acquisition circuit is obtained by fitting the actual output value and the initial measurement value. The first gain function relationship includes the sampling circuit gain coefficient and the sampling circuit offset. Calculate the voltage difference between the actual theoretical value and the initial measured value for each group, and obtain the gain compensation function relationship based on the voltage difference and the gain coefficient of the sampling circuit; The first gain function relationship and the gain compensation function relationship are combined to obtain the second gain function relationship; The actual output value of the voltage acquisition circuit is adjusted according to the second gain function relationship, and the actual measured value of the DC bus voltage is determined based on the adjusted actual output value.

4. The method according to claim 1, characterized in that, The determination of whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage includes: Calculate the voltage difference between the actual theoretical value and the initial measurement value of the voltage acquisition circuit, and determine whether the absolute value of the voltage difference is greater than a first preset threshold. If the absolute value of the voltage difference is greater than the first preset threshold, the number of deviations is accumulated, and it is determined whether the number of deviations is greater than the preset number. If the number of deviations is greater than the preset number, the calibration condition is determined to be met; otherwise, the calibration condition is determined not to be met.

5. The method according to claim 1, characterized in that, The process of determining the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal includes: Determine the theoretical amplitude constraint relationship between the three-phase voltage peak value, the duty cycle of the pulse width modulation signal, and the DC bus voltage. The theoretical amplitude constraint relationship is that the three-phase voltage peak value is equal to the product of the DC bus voltage and the real-time duty cycle. The actual theoretical value of the DC bus voltage is obtained by calculating the ratio of the actual output amplitude of the three-phase voltage to the real-time duty cycle.

6. The method according to claim 1, characterized in that, The set operating condition is a stable operating condition. Before obtaining the three-phase current of the motor controller and the corresponding motor parameter information under the set operating condition, the method further includes: The three-phase current of the motor controller and the rotor mechanical angular velocity of the motor are continuously acquired according to the preset sampling period. The three-phase current is converted into direct-axis current and quadrature-axis current in the dq coordinate system, and the rotor mechanical angular velocity is converted into rotor electrical angular velocity. The motor is determined to be in the stable operating condition based on the rotor electric angular velocity, the direct-axis current, and the quadrature-axis current.

7. The method according to claim 6, characterized in that, The step of determining whether the motor is in the stable operating condition based on the rotor electrical angular velocity, the direct-axis current, and the quadrature-axis current includes: The average rotational speed and standard deviation of rotational speed are determined based on the rotor electrical angular velocity within a preset sampling period, and the rotational speed fluctuation rate is determined based on the average rotational speed and the standard deviation of rotational speed. The average value and standard deviation of the cross-axis current are determined based on the cross-axis current within the preset sampling period, and the cross-axis current fluctuation rate is determined based on the average value and standard deviation of the cross-axis current. If, within a consecutive preset number of preset sampling periods, the rotor electrical angular velocity is greater than a second preset threshold, the speed fluctuation rate is less than a third preset threshold, the quadrature axis current fluctuation rate is less than a fourth preset threshold, and the absolute value of the direct axis current is less than a fifth preset threshold, then the motor is determined to be in the stable operating condition; otherwise, it is determined not to be in the stable operating condition.

8. The method according to claim 1, characterized in that, The parameter information of the motor includes: the inherent parameters and operating parameters of the motor. The inherent parameters include: direct-axis inductance, quadrature-axis inductance, stator resistance, and rotor permanent magnet flux linkage parameters. The operating parameters include: rotor electrical angle and rotor electrical angular velocity. The determination of the actual output amplitude of the three-phase voltage based on the parameter information and the three-phase current includes: Performing a Clarke transform on the three-phase current yields... Two-phase stationary coordinate system shaft current and Shaft current, and based on the rotor electrical angle, the shaft current. shaft current and the The Parker transformation is performed on the axis currents to obtain the direct-axis currents and quadrature-axis currents in the dq coordinate system. Based on the rotor electric angular velocity, the direct-axis inductance, the quadrature-axis inductance, the stator resistance, and the rotor permanent magnet flux linkage parameters, the direct-axis current and the quadrature-axis current are converted into direct-axis voltage and quadrature-axis voltage; Based on the rotor electrical angle, an inverse Parker transformation is performed on the direct-axis voltage and the quadrature-axis voltage to obtain the... Two-phase stationary coordinate system shaft voltage and shaft voltage, and the shaft voltage and the The shaft voltages are vector synthesized to obtain the actual output amplitude of the three-phase voltages.

9. A device for measuring DC bus voltage, characterized in that, The device includes: The data acquisition module is used to acquire the three-phase current of the motor controller under set operating conditions, as well as the corresponding motor parameter information; The data conversion module is used to determine the actual output amplitude of the three-phase voltage based on the parameter information and the three-phase current; The theoretical conversion module is used to determine the actual theoretical value of the DC bus voltage based on the actual output amplitude of the three-phase voltage and the real-time duty cycle of the pulse width modulation signal. The calibration determination module is used to determine whether the calibration conditions are met based on the actual theoretical value of the DC bus voltage, and to determine the actual measured value of the DC bus voltage based on the determination result.

10. A terminal device, characterized in that, include: The motor controller includes a processor, a memory, a communication interface, and a communication bus. The processor, the memory, and the communication interface communicate with each other through the communication bus. The motor controller is used to drive the motor to run. The memory is used to store at least one executable instruction that causes the processor to perform the operation of the DC bus voltage measurement method as described in any one of claims 1-8.

Images