Current sampling delay measurement method, system, device and computer storage medium

Abstract

The application discloses a current sampling delay measurement method, system, device and computer storage medium, and belongs to the technical field of motor control. The current sampling delay measurement method is applied to a current sampling delay measurement system, and comprises the following steps: controlling a measured motor to enter an active short-circuit state; controlling a motor controller of an auxiliary motor to adjust the rotating speed of the auxiliary motor, so that the working current frequency of the measured motor is adjusted to a target frequency; controlling the motor controller of the measured motor to record the sampling current of the measured motor, and simultaneously sending a level adjustment command to the motor controller of the measured motor, so that the level of an output port connected between the motor controller of the measured motor and an oscilloscope is changed, and the oscilloscope is triggered to synchronously acquire the reference current of the measured motor measured by a reference current measurement device; and determining the current sampling delay according to the target frequency, the sampling current and the reference current. The application can accurately and quickly obtain the current sampling delay, and avoids the decline of dynamic and steady-state control performance of vector control.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and in particular to current sampling delay measurement methods, systems, devices, and computer storage media. Background Technology

[0002] In applications such as electric vehicle main drive motors and high-performance motion control, magnetic field-oriented vector control technology is generally used to improve the dynamic response and steady-state accuracy of motor torque control.

[0003] Vector control technology includes a current sampling process. However, during the current sampling process, there may be a delay in current sampling due to various reasons. When the phase current is an alternating current, these delays will cause the sampled current value used in the software to have a phase shift relative to the actual current, which will ultimately lead to a deviation in the magnetic field orientation and affect the dynamic and steady-state control effect of vector control.

[0004] Currently, the solutions in related technologies cannot accurately and quickly obtain the delay time of the entire current sampling process, which leads to a decrease in the dynamic and steady-state control performance of vector control. Summary of the Invention

[0005] The main objective of this application is to provide a current sampling delay measurement method, system, device, and computer storage medium, which aims to accurately and quickly obtain the delay time of the entire current sampling process, thereby avoiding a decrease in the dynamic and steady-state control performance of vector control.

[0006] To achieve the above objectives, this application provides a current sampling delay measurement method applied to a current sampling delay measurement system. The system includes a motor under test, a coaxially arranged auxiliary motor under test, a reference current measuring device electrically connected to the motor under test, an oscilloscope electrically connected to the motor controller of the motor under test and the reference current measuring device, and a main control unit communicatively connected to the motor controller of the motor under test, the motor controller of the auxiliary motor under test, and the oscilloscope. The current sampling delay measurement method includes the main control unit performing the following steps:

[0007] Control the tested motor to enter an active short-circuit state;

[0008] The motor controller controlling the accompanying motor adjusts the speed of the accompanying motor to adjust the operating current frequency of the motor under test to the target frequency;

[0009] The motor controller controlling the motor under test records the sampled current of the motor under test, and simultaneously sends a level adjustment command to the motor controller of the motor under test to change the level of the output port of the motor controller of the motor under test connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the reference current measuring device.

[0010] The current sampling delay is determined based on the target frequency, the sampling current, and the reference current.

[0011] Optionally, the target frequency f e The relationship between the measured motor speed n and the number of pole pairs P is as follows:

[0012] The step of adjusting the speed of the auxiliary motor by controlling the motor controller of the auxiliary motor to adjust the operating current frequency of the motor under test to the target frequency includes:

[0013] According to the formula Calculate the target rotational speed when the operating current frequency of the motor under test is the target frequency;

[0014] The accompanying motor is controlled to run at the target speed so that the motor under test, which is coaxially arranged with the accompanying motor, runs at the target speed, thereby making the operating current frequency of the motor under test the target frequency.

[0015] Optionally, the step of determining the current sampling delay based on the target frequency, the sampling current, and the reference current includes:

[0016] The sampled current and the reference current are processed to obtain the phase difference between the sampled current and the reference current;

[0017] The current sampling delay is obtained by dividing the phase difference by the electrical angular frequency corresponding to the target frequency.

[0018] Optionally, the step of processing the sampled current and the reference current to obtain the phase difference between the sampled current and the reference current includes:

[0019] Fourier analysis was performed on the reference current and the sampled current respectively to obtain the fundamental amplitude and phase of the reference current and the sampled current;

[0020] The positive sequence component amplitudes and phases of the reference current and the sampled current are calculated based on the fundamental amplitude and phase of the reference current and the sampled current, respectively.

[0021] Based on the amplitude and phase of the positive sequence component of the reference current and the sampling circuit, the phase difference between the positive sequence component of the sampling current and the positive sequence component of the reference current is calculated.

[0022] Furthermore, to achieve the above objectives, this application also provides a current sampling delay measurement system. The current sampling delay measurement system includes a motor under test, a coaxially arranged auxiliary motor under test, a reference current measuring device electrically connected to the motor under test, and an oscilloscope electrically connected to the motor controller of the motor under test and the reference current measuring device. It also includes a main control unit communicatively connected to the motor controller of the motor under test, the motor controller of the auxiliary motor under test, and the oscilloscope. The main control unit includes:

[0023] The motor status control unit is used to control the tested motor to enter an active short-circuit state;

[0024] The motor speed control unit is used to control the motor controller of the accompanying motor to adjust the speed of the accompanying motor so as to adjust the operating current frequency of the motor under test to the target frequency.

[0025] The reference current acquisition unit is used to control the motor controller of the motor under test to record the sampled current of the motor under test, and at the same time send a level adjustment command to the motor controller of the motor under test to change the level of the output port of the motor controller of the motor under test connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the reference current measurement device.

[0026] A current sampling delay calculation unit is used to determine the current sampling delay based on the target frequency, the sampling current, and the reference current.

[0027] Optionally, the target frequency f e The relationship between the measured motor speed n and the number of pole pairs P is as follows: The motor speed control unit is specifically used for:

[0028] According to the formula Calculate the target rotational speed when the operating current frequency of the motor under test is the target frequency;

[0029] The accompanying motor is controlled to run at the target speed so that the motor under test, which is coaxially arranged with the accompanying motor, runs at the target speed, thereby making the operating current frequency of the motor under test the target frequency.

[0030] Optionally, the current sampling delay calculation unit includes:

[0031] A phase difference calculation unit is used to process the sampled current and the reference current to obtain the phase difference between them;

[0032] The delay time calculation unit is used to divide the phase difference by the electrical angular frequency corresponding to the target frequency to obtain the current sampling delay.

[0033] Optionally, the phase difference calculation unit is specifically used for:

[0034] Fourier analysis was performed on the reference current and the sampled current respectively to obtain the fundamental amplitude and phase of the reference current and the sampled current;

[0035] The positive sequence component amplitudes and phases of the reference current and the sampled current are calculated based on the fundamental amplitude and phase of the reference current and the sampled current, respectively.

[0036] Based on the amplitude and phase of the positive sequence component of the reference current and the sampling circuit, the phase difference between the positive sequence component of the sampling current and the positive sequence component of the reference current is calculated.

[0037] In addition, to achieve the above objectives, this application also provides a current sampling delay measurement device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the current sampling delay measurement method as described above.

[0038] In addition, to achieve the above objectives, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the current sampling delay measurement method as described above.

[0039] This application proposes a current sampling delay measurement method, system, device, and computer storage medium. In the current sampling delay measurement method, the main control unit first controls the motor under test to enter an active short-circuit state, and then controls the motor controller of the auxiliary motor to adjust the speed of the auxiliary motor, thereby adjusting the speed of the motor under test so that the operating current frequency of the motor under test is adjusted to the target frequency. Then, the motor controller of the motor under test records the sampling current of the motor under test, which does not require obtaining the sampling current through the chip ADC port voltage, thus acquiring the sampling current faster. At the same time, a level adjustment command is sent to the motor controller of the motor under test to change the level of the output port connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the reference current measurement device, thus achieving time synchronization between the reference current and the sampling current. Finally, the current sampling delay is determined based on the target frequency, the sampling current, and the reference current. This embodiment of the application calculates the current sampling delay time at a given speed (each speed corresponds to a current frequency) by measuring the actual current (as a "reference") of the motor under test in an active short-circuit state, and then comparing the phase of the measured current with the current value sampled in the motor controller software under the active short-circuit state. Since the former is a direct measurement using a high-precision, high-bandwidth closed-loop Hall effect sensor, it can be considered to represent the true current value. Because the latter's main control chip analog-to-digital conversion configuration and software interrupt triggering method are the same as during normal motor control, it represents the actual current value used for closed-loop control. Dividing the phase difference between the two measurements by the current frequency yields the delay time of the entire current sampling process at that frequency, overcoming the technical deficiency of related technologies that cannot accurately and quickly obtain the delay time of the entire current sampling process. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only a part of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A circuit diagram showing the two main parts that constitute the delay in the current sampling process;

[0042] Figure 2 A flowchart illustrating a current sampling delay measurement method provided in an embodiment of this application;

[0043] Figure 3 A schematic diagram illustrating the process of a current sampling delay measurement method provided in this application, corresponding to a motor operating in an active short-circuit state;

[0044] Figure 4 for Figure 3 A detailed flowchart of step 105;

[0045] Figure 5 for Figure 3 A schematic diagram of the reference current, sampling current, and trigger signal used to synchronize the recording of the two.

[0046] Figure 6 This is a schematic diagram of the structure of a current sampling delay measurement system provided in an embodiment of this application;

[0047] Figure 7 This is a schematic diagram of the structure of a current sampling delay measurement device provided in an embodiment of this application. Detailed Implementation

[0048] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that the embodiments of this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the embodiments of this application with unnecessary detail.

[0049] It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0050] It should also be understood that references to "one embodiment" or "some embodiments" in the specification of embodiments of this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0051] In applications such as electric vehicle main drive motors and high-performance motion control, field-oriented vector control technology is generally used to improve the dynamic response and steady-state accuracy of motor torque control. Taking the typical permanent magnet synchronous motor vector control as an example, its rotor field orientation requires accurate sampling of the motor phase current and rotor magnetic field position (usually referred to as the "d" axis position). The phase current is often measured using a Hall effect-based current sensor; the output of the current sensor is then conditioned and fed to the ADC (Analog to Digital Converter) port of the main control chip, and finally, the current sampling process is completed through the chip's ADC module.

[0052] During the entire current sampling process, there is a time delay (t) between the output analog voltage of the current sensor and the actual current. d1 (represented by t), conditioning circuit (its delay is t) d2 (represented by) and the chip's ADC sample-and-hold (its delay is t) d3 (This indicates) a delay. When the phase current is alternating current, these delays cause a phase shift in the sampled current value used in the software relative to the actual current, ultimately leading to a deviation in the magnetic field orientation and affecting the dynamic and steady-state control performance of vector control.

[0053] To address the aforementioned delay in current sampling, there are generally two technical solutions:

[0054] Figure 1 The diagram illustrates the main part that causes the delay in the current sampling process: the MCU (Motor Control Unit, or Inverter) has a built-in Hall current sensor and conditioning circuitry. The output V of the conditioning circuitry in the diagram is shown. in Connect to the ADC channel of the internal MCU chip. The first approach (referred to as the theoretical calculation method) typically does not consider the chip's ADC sampling delay t in the software. d3 The delay t is calculated based solely on the parameters of the conditioning circuit. d2 Delay the current sensor body by t d1 Set it to the typical value given in the product manual. Then, when calculating the feedback dq current, subtract ω from the sampled rotor position. e (t d1 +t d2 (ω) e The rotor position at the moment corresponding to the three-phase sampled current is obtained by using the stator current angular frequency of the motor, so as to perform coordinate transformation to obtain the feedback dq current.

[0055] The second approach (referred to as the torque calibration method) involves calibrating the total delay time of the entire current sampling process using a high-speed motor test bench. One calibration method is to apply a negative Id command at high speed and adjust the total delay time t.d This ensures that the mechanical torque measured at the shaft end is equal to the frictional torque at that speed plus the torque caused by iron loss.

[0056] The first technical solution does not consider the additional delay caused by the PCB (Printed Circuit Board) layout of the ADC sampling and conditioning circuit, nor does it consider that the interaction of the magnetic fields generated by the currents in each phase will increase the total delay time compared to the delay time t of a single Hall effect sensor. d1 Different problems. On the other hand, when the Hall current sensor is manufactured in-house by the motor controller manufacturer, there is often no high-precision equipment to measure the accurate delay time of the current sensor.

[0057] The second technical solution requires knowledge of the iron loss torque of the motor under negative Id control at different speeds, which cannot be obtained without an electromagnetic model of the motor. Even with an electromagnetic model of the experimental motor, verifying the accuracy of the finite element simulation results of the iron loss requires a significant amount of work.

[0058] Therefore, neither of these two technical solutions in the related technologies can accurately and quickly obtain the delay time of the entire current sampling process, which leads to a decrease in the dynamic and steady-state control effect of vector control.

[0059] To improve AC motor design capabilities, it is necessary to measure the motor's torque, flux linkage, and losses under different dq currents. This places high demands on the accuracy of vector control (i.e., the distribution relationship between the dq axis current and output voltage sampled by the software must be the same as the current and voltage in the actual motor); otherwise, there will be a deviation between the actual dq current and the commanded value. Furthermore, to improve the torque response performance of AC motor vector control, the accuracy of vector control must also be improved; otherwise, the coupling between the dq axes will affect the dynamic torque control effect.

[0060] The main factors affecting the accuracy of vector control are the accuracy of magnetic field position detection (i.e., magnetic field orientation) and the accuracy of current sampling. Therefore, this application addresses the problem that the delay in the current sampling process seriously affects the accuracy of current sampling by proposing a method for testing and calculating this delay. By comparing the phase difference between the AC phase current used in the motor control software (referred to as the "sampled" current) and the current obtained through a high-precision measurement scheme (referred to as the "reference current"), data processing (referred to as the "delay time data processing method") can be performed to obtain the delay time of the controller's sampled current relative to the reference current. This delay time data processing method varies depending on whether the measured reference current is in the form of voltage or current.

[0061] The current sampling delay measurement method, system, device, and computer storage medium provided in this application are specifically described through the following embodiments. First, the current sampling delay measurement method in this application embodiment is described.

[0062] Reference Figure 2 , Figure 2 This is a flowchart illustrating a current sampling delay measurement method according to an embodiment of this application. This method can be applied to a current sampling delay measurement system. The system includes a motor under test, a coaxially mounted auxiliary motor, a reference current measuring device electrically connected to the motor under test, an oscilloscope electrically connected to the motor controller of the motor under test and the reference current measuring device, and a main control unit communicatively connected to the motor controller of the motor under test, the motor controller of the auxiliary motor, and the oscilloscope. Figure 2 As shown, the current sampling delay measurement method provided in this embodiment includes steps S10 to S40 executed by the main control unit described above.

[0063] Step S10: Control the tested motor to enter an active short-circuit state;

[0064] It should be noted that this embodiment determines the total delay time of the current sampling process of the motor controller (or inverter) (including the current sensor, hardware conditioning circuit and chip ADC sampling) through actual measurement, which is more accurate than the theoretical calculation result of Scheme 1 in the above-mentioned related technologies; and it is more accurate and has less workload than the torque calibration method of Scheme 2 in the above-mentioned related technologies, and has a wider range of application scenarios.

[0065] As an example, when the motor under test is a permanent magnet synchronous motor, the motor controller can be connected to the permanent magnet synchronous motor, and the permanent magnet synchronous motor can be driven by a dynamometer bench (i.e., a dual-motor drag test bench) to operate in a state where the output terminals of each phase of the motor are directly short-circuited (referred to as ASC) or short-circuited through a balanced load. Then, a high-precision closed-loop Hall current sensor is used to measure the current of each phase of the motor under test in the active short-circuit state.

[0066] As an example, the motor under test can be put into an active short-circuit state by controlling all upper bridge arms or all lower bridge arms of the power conversion circuit in the motor controller of the motor under test to be turned on.

[0067] Step S20: The motor controller of the test motor adjusts the speed of the test motor so as to adjust the operating current frequency of the test motor to the target frequency.

[0068] It should be noted that in this embodiment, since the test motor and the motor under test are coaxially connected and have the same speed, the shaft speed is controlled by the closed-loop speed control of the test motor. When the motor under test is a permanent magnet synchronous motor, each speed corresponds to a current frequency.

[0069] As an example, in this embodiment, the target frequency f e The relationship between the measured motor speed n and the number of pole pairs P is as follows: The above step S20 can be achieved in the following way: according to the formula The target speed is calculated when the operating current frequency of the motor under test is the target frequency. The motor controller of the accompanying motor is used to control the accompanying motor to run at the target speed, so that the motor under test, which is set on the same axis as the accompanying motor, also runs at the target speed, thereby making the operating current frequency of the motor under test the target frequency.

[0070] Step S30: Control the motor controller of the motor under test to record the sampling current of the motor under test, and at the same time send a level adjustment command to the motor controller of the motor under test to change the level of the output port of the motor controller of the motor under test connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the reference current measuring device.

[0071] It should be noted that in this embodiment, the motor controller of the motor under test directly records the sampled current, instead of obtaining the sampled current through the chip ADC port voltage as in related technologies. This avoids the delay caused by the ADC port sampling and holding time. Specifically, the ADC module of the internal chip of the motor controller of the motor under test completes the current sampling conversion at equal time intervals, and saves the result of each sampling in the chip's timing task. Finally, the sampling results for a period of time are exported to the main control unit through an external communication interface. In addition, since the reference current measurement and the sampled current measurement are performed in different physical systems, the measurement time of the two needs to be synchronized. Therefore, in this embodiment, while the motor controller of the motor under test records the sampled current, it also sends a level adjustment command to the motor controller of the motor under test. This changes the level of the output port of the chip on the internal chip of the motor controller of the motor under test that is connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current, thereby achieving the purpose of synchronizing the reference current and the sampled current time system. The technical means used in this embodiment to achieve time system synchronization are simple and reliable, and do not require additional cost compared to the motor control systems commonly used in related technologies.

[0072] As an example, the specific process for synchronizing the reference current and sampling current time system in this embodiment is as follows: After receiving the level adjustment command input from the external communication interface, the motor controller of the motor under test starts to pull the level of a certain digital output port high or low, and simultaneously records the sampling current and the delay time t1 of the port level change relative to the current sampling and holding time; an oscilloscope used to record the reference current is connected to this output port, and the oscilloscope is triggered when the level of the output port changes. Thus, in the oscilloscope data, the time t0 of the level change of the output port minus t1 is the time t of the first current sampling by the ADC inside the motor controller. 00This completes the synchronization of the reference current and the sampling current. The main control unit exports the reference current data stored in the oscilloscope, the corresponding time at each recording point, and the sampling current data stored in the controller; it then uses data processing software to plot the reference current and its time, and then, at time t... 00 The sampling current is plotted starting at a specific time, thus providing a visual display of the reference current and the sampling current within the same time frame.

[0073] Step S40: Determine the current sampling delay based on the target frequency, sampling current, and reference current.

[0074] In some feasible embodiments, step S40 includes:

[0075] Step S41: Process the sampled current and the reference current to obtain their phase difference;

[0076] Step S42: Divide the phase difference by the electrical angular frequency corresponding to the target frequency to obtain the current sampling delay.

[0077] Step S41 may further include: performing Fourier analysis on the reference current and the sampling current respectively to obtain the fundamental amplitude and phase of the reference current and the sampling current; calculating the positive sequence component amplitude and phase of the reference current and the sampling current respectively based on the fundamental amplitude and phase of the reference current and the sampling current; calculating the phase difference between the positive sequence component of the sampling current and the positive sequence component of the reference current based on the positive sequence component amplitude and phase of the reference current and the sampling circuit.

[0078] It should be noted that in this embodiment, given the target frequency of the motor under test, the measured sampling current, and the reference current used as a reference standard, the positive sequence phase of the reference current and the sampling current can be obtained first using the symmetrical component method. Then, the phase difference between the positive sequence component of the sampling current and the positive sequence component of the reference current is calculated. Finally, the current sampling delay is obtained by dividing the current phase difference by the electrical angular frequency.

[0079] As an example, when the measured reference current is the phase current under ASC (Active Short Circuit), Fourier analysis (FFT) can be performed on the reference and sampling currents of each phase. Then, based on the fundamental amplitude and phase of the FFT of each phase reference current, the amplitude and phase of the positive sequence component are obtained using the symmetrical component method. Similarly, the amplitude and phase of the positive sequence component of each phase sampling current are obtained. The total delay time of the sampling process can be obtained by dividing the phase difference between the two positive sequence components by the electrical angular frequency.

[0080] It should be noted that in this embodiment, data is collected only through the motor controller and oscilloscope of the motor under test. The data processing is implemented by the main control unit, which is connected to the motor controller and oscilloscope of the motor under test and is capable of running data processing software.

[0081] This embodiment proposes a current sampling delay measurement method. The method involves measuring the actual current (as a "reference") of the motor under test while it operates in an active short-circuit state. This reference current is then compared with the current value sampled in the motor controller software under the active short-circuit state to calculate the current sampling delay time at that speed (for permanent magnet synchronous motors, each speed corresponds to a current frequency). Since the former is a direct measurement using a high-precision, high-bandwidth closed-loop Hall effect sensor, it can be considered to represent the true current value. Because the ADC configuration and software interrupt triggering method of the main control chip are the same as during normal motor control when measuring the current in the latter, it represents the actual current value used for closed-loop control. Dividing the phase difference between the two measurements by the current frequency yields the delay time of the entire current sampling process at that frequency, overcoming the technical deficiency of related technologies that cannot accurately and quickly obtain the delay time of the entire current sampling process.

[0082] This embodiment addresses the problem of degraded vector control performance caused by the delay between phase current sampling and the actual current in AC motor control. It proposes an easy-to-implement current sampling delay time measurement scheme. This scheme only requires a dynamometer bench (or a simple dual-motor drag bench), an oscilloscope, and a reference current measurement device (such as a closed-loop Hall sensor integrated into a power analyzer), requiring no other testing resources. By compensating for the magnetic field orientation angle using the measurement results of this scheme, the accurate dq-axis current of the motor can be obtained, thus enabling high-dynamic-performance AC motor vector control. Since this scheme accurately measures the dq-axis current of the motor, the simulation results of the designed motor electromagnetic scheme can be verified by combining the motor torque, input line voltage, and losses under this dq-axis current, thereby improving motor design capabilities.

[0083] In some feasible embodiments, the step of simultaneously sending a level adjustment command to the motor controller of the motor under test in step S30 above includes:

[0084] While the motor controller of the motor under test records the sampling current of the first group of motors under test, a level adjustment command is simultaneously sent to the motor controller of the motor under test.

[0085] In this embodiment, in order to ensure the time synchronization of the sampling current and the reference current, when recording the first set of sampling currents, it is necessary to synchronously change the level of the output port of the motor controller of the motor under test connected to the oscilloscope.

[0086] In some feasible embodiments, the aforementioned reference current measuring device is a closed-loop Hall current sensor; the step S30 above, which involves sending a level adjustment command to the motor controller of the motor under test to change the level of the output port connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the reference current measuring device, includes:

[0087] A level adjustment command is sent to the motor controller of the motor under test to change the level of the output port of the motor controller connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the closed-loop Hall current sensor.

[0088] As an example, in this embodiment, ASC is used to measure the motor phase current. During the measurement of the current sampling delay time, the motor inverter operates in ASC mode. At this time, there are no PWM (Pulse Width Modulation) related harmonics in the motor phase current, resulting in less interference to the measurement. Compared to a scheme that only applies AC current to the Hall sensor for sampling and measures the Hall sensor's delay time, this embodiment has the advantage of considering both the influence of the magnetic field of each phase current on the interference of each phase Hall sensor and the total delay time of the entire current sampling process.

[0089] As an example, the reference current measurement method used in this embodiment is to connect the motor controller to the permanent magnet synchronous motor, and use a dynamometer bench (i.e., a dual-motor drag test bench) to drive the permanent magnet synchronous motor to operate in a state where the output terminals of each phase of the motor are directly short-circuited (ASC) or short-circuited through a balanced load. Then, a high-precision closed-loop Hall current sensor is used to measure the active short-circuit current of each phase of the motor.

[0090] As an example, this embodiment is an implementation method for measuring the delay time of the sampled current relative to the reference current by operating the motor in ASC mode. Figure 3 This is a flowchart of the operation of this implementation method. Step 100 is as follows: Pass the AC connection cable between the MCU and the permanent magnet synchronous motor through the input side of the high-precision closed-loop Hall current sensor; connect the closed-loop Hall output to the oscilloscope; connect the MCU's digital output port to the oscilloscope so that the oscilloscope can be triggered to capture and record data through this port; the MCU's built-in software has the function of periodically recording the sampled current, and synchronously changes the level of the digital output port when recording the first set of sampled currents. Step 101 is as follows: Through software operation, control all upper or lower bridge arms of the motor controller power section of the motor under test to the ASC state. Step 102 is as follows: Control the speed of the motor under test so that the frequency of the short-circuit current of the motor under test is the target frequency, f. e The relationship between the measured motor speed n and the number of pole pairs P is as follows: Step 103 involves sending a command to the MCU of the motor under test to change the digital output port level via the communication port. The MCU then synchronously begins recording the sampling current, the current sampling and holding time, and the port level change time. Step 104 involves the oscilloscope being configured in trigger mode; the change in the digital output port level triggers the oscilloscope to capture the "reference" current measurement result from the external closed-loop Hall effect sensor. Step 105 involves processing the reference current and the sampling current to obtain their phase difference. Dividing the phase difference by the electrical angular frequency yields the total delay time t during the current sampling process. d .

[0091] The following is combined with Figure 4 The sub-steps of step 105 are explained in detail below. In step 106, the lag time t1 between the MCU changing the port level and the current sampling and holding time is calculated. Assuming the trigger signal transition occurs at time t0 when the oscilloscope records data, the first current sampled by the MCU occurs at time t1 when the oscilloscope records data. 00 At time t 00 =t0-t1; Therefore, based on this time relationship, all the sampled current data recorded by the MCU and all the reference measured currents recorded by the oscilloscope can be plotted on the same graph. Figure 5 This is an example of such a diagram. Figure 5 In the middle: the reference current consists of three sinusoidal waveforms with small amplitude interference glitches (the amplitude of the displayed waveform is reduced to facilitate comparison with the sampled current); the signal that jumps at time t0 is the MCU digital port trigger signal amplified 50 times; and the three sinusoidal waveforms with large amplitude and no glitches are the sampled current. Figure 5 The reference current and trigger signal are signals captured by the oscilloscope trigger, and the sampling current is a sampling current signal synchronized with the oscilloscope signal plotted according to the method in step 106. In step 107, Fourier analysis is performed on the reference current and sampling current of each phase to obtain the fundamental amplitude and phase of each phase. In step 108, the amplitude and phase φ of the positive sequence component of the reference current are calculated based on the amplitude and phase of the reference current of each phase obtained in step 107. p1 And based on the same method, the amplitude and phase φ of the positive sequence component of the sampled current are calculated. p2 In step 109, the phase lag between the positive-sequence component of the sampled current and the positive-sequence component of the reference current is calculated, and then divided by the electrical angular frequency to obtain the delay time, i.e., the delay time.

[0092] Furthermore, this application embodiment also provides a main control unit for executing the current sampling delay measurement method provided in any of the above embodiments.

[0093] In this embodiment, the main control unit can be set in one current sampling delay measurement device, or it can be divided into multiple functional modules and distributed in multiple current sampling delay measurement devices. This embodiment does not limit this.

[0094] The main control unit proposed in this embodiment belongs to the same inventive concept as the current sampling delay measurement method proposed in the above embodiments. Technical details not described in detail in this embodiment can be found in any of the above embodiments. Furthermore, this embodiment has the same beneficial effects as the current sampling delay measurement method.

[0095] Furthermore, embodiments of this application also provide a current sampling delay measurement system, referring to... Figure 6 , Figure 6 This is a schematic diagram of the structure of a current sampling delay measurement system provided in an embodiment of this application, as shown below. Figure 6 As shown, in this embodiment, the current sampling delay measurement system includes a motor under test 100, a companion motor 200 coaxially arranged with the motor under test 100, a reference current measuring device 300 electrically connected to the motor under test 100, and an oscilloscope 400 electrically connected to the motor controller of the motor under test 100 and the reference current measuring device 300. It also includes a main control unit 500 communicatively connected to the motor controller of the motor under test 100, the motor controller of the companion motor 200, and the oscilloscope 400. The main control unit 500 may include:

[0096] The motor status control unit is used to control the tested motor 100 to enter an active short-circuit state;

[0097] The motor speed control unit is used to control the motor controller of the test motor 200 to adjust the speed of the test motor 200 so as to adjust the operating current frequency of the tested motor 100 to the target frequency.

[0098] The reference current acquisition unit is used to control the motor controller of the motor under test 100 to record the sampled current of the motor under test 100, and at the same time send a level adjustment command to the motor controller of the motor under test 100 to change the level of the output port of the motor controller of the motor under test 100 connected to the oscilloscope 400, triggering the oscilloscope 400 to synchronously acquire the reference current of the motor under test 100 measured by the reference current measuring device 300;

[0099] A current sampling delay calculation unit is used to determine the current sampling delay based on the target frequency, the sampling current, and the reference current.

[0100] It is understood that this embodiment corresponds to the application scenario of the current sampling delay measurement method provided in the above embodiments. In this embodiment, the specific selection of the reference current measuring device 300 will determine how to obtain the reference current. To calculate the delay time, the sampled current recorded by the motor controller and the reference current recorded by the oscilloscope 400 need to be imported as input parameters into the main control unit 500, which can run data processing software (such as MATLAB).

[0101] In some feasible embodiments, the reference current measuring device 300 is a closed-loop Hall current sensor. The AC connection line between the motor controller of the motor under test 100 and the motor under test 100 passes through the input terminal of the closed-loop Hall current sensor, and the output terminal of the closed-loop Hall current sensor is connected to the oscilloscope 400. The closed-loop Hall current sensor is used to transmit the measured reference current of the motor under test 100 to the oscilloscope 400 when the motor under test 100 is operating in an active short-circuit state.

[0102] In some feasible embodiments, the target frequency f e The relationship between the measured motor speed n and the number of pole pairs P is as follows: The motor speed control unit can be used for:

[0103] According to the formula Calculate the target rotational speed when the operating current frequency of the motor under test is the target frequency;

[0104] The accompanying motor is controlled to run at the target speed so that the motor under test, which is coaxially arranged with the accompanying motor, runs at the target speed, thereby making the operating current frequency of the motor under test the target frequency.

[0105] In some feasible embodiments, the current sampling delay calculation unit may include:

[0106] A phase difference calculation unit is used to process the sampled current and the reference current to obtain the phase difference between them;

[0107] The delay time calculation unit is used to divide the phase difference by the electrical angular frequency corresponding to the target frequency to obtain the current sampling delay.

[0108] In some feasible embodiments, the phase difference calculation unit can be used to:

[0109] Fourier analysis was performed on the reference current and the sampled current respectively to obtain the fundamental amplitude and phase of the reference current and the sampled current;

[0110] The positive sequence component amplitudes and phases of the reference current and the sampled current are calculated based on the fundamental amplitude and phase of the reference current and the sampled current, respectively.

[0111] Based on the amplitude and phase of the positive sequence component of the reference current and the sampling circuit, the phase difference between the positive sequence component of the sampling current and the positive sequence component of the reference current is calculated.

[0112] The current sampling delay measurement system provided in this embodiment belongs to the same inventive concept as the current sampling delay measurement method provided in the above embodiments. Technical details not described in detail in this embodiment can be found in any of the above embodiments. Furthermore, this embodiment has the same beneficial effects as the current sampling delay measurement method.

[0113] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0114] Furthermore, this application embodiment also provides a current sampling delay measurement device. The current sampling delay measurement method applied to the current sampling delay measurement system described above can be executed by a main control unit. This main control unit can be implemented through software and / or hardware and integrated into the current sampling delay measurement device. The current sampling delay measurement device can be a PC (personal computer), mobile phone, laptop, tablet computer, or other terminal device capable of communicating with the motor controller of the motor under test, the motor controller of the accompanying motor, and an oscilloscope, and capable of running data processing software.

[0115] Reference Figure 7 , Figure 7 This is a schematic diagram of the hardware structure of a current sampling delay measurement device according to an embodiment of this application. Figure 7As shown, the current sampling delay measurement device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen and an input unit such as a keyboard; optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk storage device. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0116] Those skilled in the art will understand that Figure 7 The structure shown does not constitute a limitation on the current sampling delay measurement device and may include more or fewer components than illustrated, or combine certain components, or have different component arrangements. Figure 7 As shown, the memory 1005, which serves as a storage medium, may include an operating system, a data storage module, a network communication module, a user interface module, and computer programs.

[0117] exist Figure 7 In the current sampling delay measurement device shown, the network interface 1004 is mainly used for data communication with other devices; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in this embodiment can be set in the current sampling delay measurement device. The current sampling delay measurement device calls the computer program stored in the memory 1005 through the processor 1001 and executes the current sampling delay measurement method applied to the current sampling delay measurement device provided in any of the above embodiments.

[0118] The current sampling delay measurement device proposed in this embodiment belongs to the same inventive concept as the current sampling delay measurement method for motor controllers proposed in the above embodiments. Technical details not described in detail in this embodiment can be found in any of the above embodiments. Furthermore, this embodiment has the same beneficial effects as the current sampling delay measurement method.

[0119] Furthermore, embodiments of this application also provide a computer-readable storage medium, which may be a non-volatile computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the current sampling delay measurement method provided in any of the above embodiments.

[0120] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0121] The above is a detailed description of the preferred embodiments of this application. However, the embodiments of this application are not limited to the above-described implementation methods. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the embodiments of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of the embodiments of this application.

Claims

1. A current sampling delay measurement method, applied to a current sampling delay measurement system, the system comprising a motor under test, a coaxially arranged auxiliary motor under test, a reference current measuring device electrically connected to the motor under test, an oscilloscope electrically connected to a motor controller of the motor under test and the reference current measuring device, and further comprising a main control unit communicatively connected to the motor controller of the motor under test, the motor controller of the auxiliary motor under test, and the oscilloscope, characterized in that, The current sampling delay measurement method includes the following steps performed by the main control unit: Control the tested motor to enter an active short-circuit state; The motor controller controlling the accompanying motor adjusts the speed of the accompanying motor to adjust the operating current frequency of the motor under test to the target frequency; The motor controller controlling the motor under test records the sampled current of the motor under test, and simultaneously sends a level adjustment command to the motor controller of the motor under test to change the level of the output port of the motor controller of the motor under test connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the reference current measuring device. The current sampling delay is determined based on the target frequency, the sampling current, and the reference current.

2. The current sampling delay measurement method as described in claim 1, characterized in that, The target frequency f e The relationship between the measured motor speed n and the number of pole pairs P is as follows: The step of adjusting the speed of the auxiliary motor by controlling the motor controller of the auxiliary motor to adjust the operating current frequency of the motor under test to the target frequency includes: According to the formula Calculate the target rotational speed when the operating current frequency of the motor under test is the target frequency; The accompanying motor is controlled to run at the target speed so that the motor under test, which is coaxially arranged with the accompanying motor, runs at the target speed, thereby making the operating current frequency of the motor under test the target frequency.

3. The current sampling delay measurement method as described in claim 1, characterized in that, The step of determining the current sampling delay based on the target frequency, the sampling current, and the reference current includes: The sampling current and the reference current are processed to obtain their phase difference; The current sampling delay is obtained by dividing the phase difference by the electrical angular frequency corresponding to the target frequency.

4. The current sampling delay measurement method as described in claim 3, characterized in that, The step of processing the sampled current and the reference current to obtain their phase difference includes: Fourier analysis was performed on the reference current and the sampled current respectively to obtain the fundamental amplitude and phase of the reference current and the sampled current; The positive sequence component amplitudes and phases of the reference current and the sampled current are calculated based on the fundamental amplitude and phase of the reference current and the sampled current, respectively. Based on the amplitude and phase of the positive sequence component of the reference current and the sampling circuit, the phase difference between the positive sequence component of the sampling current and the positive sequence component of the reference current is calculated.

5. A current sampling delay measurement system, characterized in that, The current sampling delay measurement system includes a motor under test, a companion motor coaxially arranged with the motor under test, a reference current measuring device electrically connected to the motor under test, and an oscilloscope electrically connected to the motor controller of the motor under test and the reference current measuring device. It also includes a main control unit communicatively connected to the motor controller of the motor under test, the motor controller of the companion motor, and the oscilloscope. The main control unit includes: The motor status control unit is used to control the tested motor to enter an active short-circuit state; The motor speed control unit is used to control the motor controller of the accompanying motor to adjust the speed of the accompanying motor so as to adjust the operating current frequency of the motor under test to the target frequency. The reference current acquisition unit is used to control the motor controller of the motor under test to record the sampled current of the motor under test, and at the same time send a level adjustment command to the motor controller of the motor under test to change the level of the output port of the motor controller of the motor under test connected to the oscilloscope, triggering the oscilloscope to synchronously acquire the reference current of the motor under test measured by the reference current measurement device. A current sampling delay calculation unit is used to determine the current sampling delay based on the target frequency, the sampling current, and the reference current.

6. The current sampling delay measurement system as described in claim 5, characterized in that, The target frequency f e The relationship between the measured motor speed n and the number of pole pairs P is as follows: The motor speed control unit is specifically used for: According to the formula Calculate the target rotational speed when the operating current frequency of the motor under test is the target frequency; The accompanying motor is controlled to run at the target speed so that the motor under test, which is coaxially arranged with the accompanying motor, runs at the target speed, thereby making the operating current frequency of the motor under test the target frequency.

7. The current sampling delay measurement system as described in claim 6, characterized in that, The current sampling delay calculation unit includes: A phase difference calculation unit is used to process the sampled current and the reference current to obtain the phase difference between them; The delay time calculation unit is used to divide the phase difference by the electrical angular frequency corresponding to the target frequency to obtain the current sampling delay.

8. The current sampling delay measurement system as described in claim 7, characterized in that, The phase difference calculation unit is specifically used for: Fourier analysis was performed on the reference current and the sampled current respectively to obtain the fundamental amplitude and phase of the reference current and the sampled current; The positive sequence component amplitudes and phases of the reference current and the sampled current are calculated based on the fundamental amplitude and phase of the reference current and the sampled current, respectively. Based on the amplitude and phase of the positive sequence component of the reference current and the sampling circuit, the phase difference between the positive sequence component of the sampling current and the positive sequence component of the reference current is calculated.

9. A current sampling delay measurement device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the current sampling delay measurement method as described in any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the current sampling delay measurement method as described in any one of claims 1 to 4.

Images