Method for testing no-load loss of motor

Abstract

The application discloses a kind of motor no-load loss test methods, S1, motor zero calibration, including no-load torque test and motor zero calibration;S2, zero torque ammeter calibration: dynamometer controls motor speed, controller host computer selects current control mode, according to the motor zero calibration at corresponding speed zero torque ammeter calibration is carried out;S3, carry out no-load loss test: dynamometer controls motor speed, controller host computer selects torque control mode, given motor torque command is zero, carries out no-load loss test, test data is recorded to bench, and the no-load loss value is calculated;S4, the no-load loss data measured is analyzed, according to specific data performance and input no-load loss index motor zero calibration, no-load current table calibration, to reduce no-load loss.The application can obtain the control parameter of motor no-load by calibration, to carry out the test and calculation of motor no-load loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, in particular to a kind of motor no-load loss testing method. BACKGROUND

[0002] Because new energy vehicles have the incomparable advantages of traditional fuel vehicles, such as small pollution and low energy consumption, in recent years, the Chinese government has vigorously promoted the development of new energy vehicles. As an important component in new energy vehicles, permanent magnet synchronous motor has the characteristics of high efficiency, high power factor and high power density, so it has been widely used in new energy vehicle electric drive system in recent years. For new energy vehicles, the existence of motor itself will also bring energy loss to the whole vehicle, especially for hybrid vehicles, whose power source consists of engine and motor. When the torque output is not performed, the motor will rotate with the output shaft of the vehicle and be in the no-load running state due to the hard connection of the mechanical structure of the motor and the output shaft. The existence of motor no-load loss is equivalent to adding part of the load to the running vehicle, which will consume additional energy. This is not conducive to the power performance and economy of electric vehicles, so it is necessary to study a kind of permanent magnet synchronous motor no-load loss calibration, testing and reducing method. SUMMARY

[0003] The present application provides a kind of motor no-load loss testing method, the control parameters of motor no-load can be obtained by calibration, so as to test and calculate the no-load loss of motor, and the motor no-load loss value can be effectively reduced according to the system input and the measured no-load data, and the power performance and economy of new energy vehicles are improved.

[0004] The technical scheme for solving the above problems is as follows:

[0005] The motor no-load loss testing method comprises the following steps:

[0006] S1, motor zero calibration, including no-load torque test and motor zero calibration;

[0007] S2, zero torque ammeter calibration: dynamometer controls motor speed, controller host selects current control mode, and zero torque ammeter calibration is carried out at corresponding speed according to calibrated motor zero;

[0008] S3, no-load loss test: dynamometer controls motor speed, controller host selects torque control mode, gives zero motor torque command, carries out no-load loss test, bench records test data, and calculates no-load loss value;

[0009] S4, analyze the measured no-load loss data, and calibrate motor zero according to specific data performance and input no-load loss index, to reduce no-load loss.

[0010] Further, the no-load torque test in step S1 includes: disconnecting the three-phase connection line between the motor and the controller, and driving the motor at a set speed step by the dynamometer bench until the maximum speed of the motor, and measuring the torque of the motor in the no-load state corresponding to the speed.

[0011] Further, the motor zero calibration in step S1 includes:

[0012] The bench feedback torque is the measured no-load torque of the motor, the three-phase line between the motor and the controller is connected, the low-voltage line bundle of the controller is connected, the low-voltage 12V and the rated voltage of the high voltage on the controller are connected, the current mode is selected on the controller host computer, the motor is driven to rotate to the set speed by the dynamometer, and the given d-axis current is given with the measured no-load torque as the reference. Under the condition that the motor has sufficient residual flux, the initial zero value is adjusted to make the torque measured by the bench in the present state more than 90% of the no-load torque.

[0013] After the calibration at one speed is completed, the dynamometer continues to drive the motor to rotate at a set speed step, and the above steps are repeated until the motor speed is the maximum speed, so that the motor torque measured by the dynamometer at the motor zero position in the full speed range is the no-load torque.

[0014] Further, the zero torque current table calibration in step S2 is based on the completion of the motor zero calibration. The motor is driven to rotate to the set speed by the dynamometer, the current mode is selected on the controller host computer, and the d-axis and q-axis currents are calibrated to make the bench feedback motor torque fluctuate around zero under the condition that the motor has sufficient residual flux, and the corresponding speed, d-axis and q-axis currents are recorded.

[0015] After the calibration at one speed is completed, the dynamometer continues to drive the motor to rotate at a set speed step, and the above steps are repeated until the motor speed is the maximum speed, so that the motor torque measured by the dynamometer at the motor zero position in the full speed range is the no-load torque.

[0016] Further, the test of no-load loss in step S3 is that after the given motor torque command is zero, the dynamometer drives the motor to rotate at a set speed step, and the motor speed, motor torque, bus voltage and bus current are recorded by the bench when the torque range is around zero.

[0017] The motor no-load loss is calculated according to the data recorded by the bench:

[0018] Motor speed x motor torque / 9550 = motor mechanical power;

[0019] Bus voltage x bus current = electric power;

[0020] Motor no-load loss = motor mechanical power + electric power.

[0021] Further, the step S4 is to reduce the motor no-load loss by calibration, analyze the measured no-load loss data: the motor torque, motor power, bus current, bus power at different motor speeds, evaluate the test results according to the customer input no-load loss standard, if the requirement is not met, reduce the actual torque of the motor at zero torque command and reduce the bus current to calibrate the motor zero position and the no-load current meter, so as to reduce the no-load loss.

[0022] Further, the process of reducing the no-load loss by motor zero calibration is: start the dynamometer to drive the motor to rotate, adjust the motor zero position according to the measured no-load torque, so as to make it accurate and reduce the error, avoid the current component on the d-axis or q-axis due to the zero position error, and reduce the no-load loss from the motor torque aspect.

[0023] Further, the process of reducing the no-load loss by no-load current meter calibration is: observe the real-time field weakening voltage margin, first reduce the d-axis current as much as possible under the condition that the field weakening voltage margin is sufficient, adjust the q-axis current, and observe whether the motor torque is zero, so as to avoid excessive current loss, thereby achieving the purpose of reducing the bus DC current, and further reducing the motor no-load loss.

[0024] Further, the motor is a permanent magnet synchronous motor.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] The present application describes a complete method for reducing the motor no-load loss by testing the no-load torque, calibrating the motor zero position at no-load, and calibrating the control current at zero torque. The method is simple and easy to understand, and can fundamentally reduce the motor no-load loss, thereby reducing unnecessary energy consumption of the motor on the new energy vehicle and improving the power and economy of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a flowchart of the calibration, testing and reduction method of the permanent magnet synchronous motor no-load loss of the present application.

[0028] Figure 2 is a flowchart of the motor no-load torque testing method of the present application.

[0029] Figure 3 is a flowchart of the motor zero position no-load calibration of the present application.

[0030] Figure 4 is a flowchart of the motor zero torque current meter calibration of the present application.

[0031] Figure 5 is a flow chart of reducing motor no-load loss of the application. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail with reference to the accompanying drawings. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. The embodiments described by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be simply understood as a limitation of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person skilled in the art without creative work fall within the scope of protection of the present application.

[0033] The present application will be described in detail below with reference to the accompanying drawings.

[0034] The test method of motor no-load loss, the motor is a permanent magnet synchronous motor, comprising the following steps:

[0035] S1, motor zero calibration, including no-load torque test and motor zero calibration;

[0036] The no-load torque test in step S1 includes: disconnecting the three-phase connection line between the motor and the controller, the dynamometer bench drives the motor to rotate at a set speed step, until the maximum speed of the motor, and the torque of the motor in the no-load state at the corresponding speed is measured.

[0037] Referring to Figure 2 , disconnect the three-phase line connection between the motor and the controller before driving the motor to rotate using the dynamometer, to prevent the motor speed from being too high due to high back electromotive force and damaging the controller hardware; set the maximum driving speed protection threshold and the speed driving step of the dynamometer; start the dynamometer and enter the bench speed mode; the dynamometer drives the motor to rotate at a set speed step, and the speed reaches the set speed and stabilizes for about 2s; the dynamometer continues to drive the motor to rotate at a set speed step until the maximum speed threshold of the motor; the dynamometer reduces the speed to zero; view the no-load torque at each speed recorded by the bench and export.

[0038] Motor zero calibration: make the bench feedback torque the measured motor no-load torque, connect the three-phase line between the motor and the controller, the controller low-voltage wire harness, the controller 12V low-voltage and the rated voltage of the high-voltage, the controller host selects the current mode, the dynamometer drives the motor to rotate to the set speed, and the measured no-load torque is used as a reference to give the d-axis current. Under the condition that the motor has sufficient weak magnetic margin, adjust the initial zero value to make the torque measured by the bench in the present state more than 90% of the no-load torque.

[0039] After the end of the calibration at one speed, the dynamometer continues to drag the motor to rotate at a set speed step, and the above steps are repeated until the motor speed is the maximum speed, so that the motor zero position is measured by the dynamometer in the full speed range. The torque is the no-load torque.

[0040] Calibrate the motor zero position to the no-load torque. The motor no-load torque measured in step S1 in the single motor state is used as the reference value to calibrate the motor zero position, so that the motor zero position is accurate and correct, and there is no current component due to inaccurate zero position in the no-load state, so that the torque is too large to affect the no-load loss. Referring to Figure 3 , comprising the following steps:

[0041] First step: connect the three-phase lines between the motor and the controller, connect the relevant sensors and power analyzers, ensure that the wire harness connection between the motor and the controller is normal; the low-voltage (usually 12V) on the controller is brushed to write the corresponding control software, and the host computer is used to check whether the controller communication is normal, and whether the motor body and control parameters of the motor and the controller are correct. If it is normal, proceed to the next step, otherwise, continue after troubleshooting and solving the problem.

[0042] Second step: set the maximum drag speed protection threshold of the dynamometer, the speed drag step on the bench, the rated voltage on the controller, start the dynamometer, enter the bench speed mode, and be in a free state (the bench does not control the motor speed to zero, and the motor can rotate freely).

[0043] Third step: clear the original motor zero position value in the host computer, and use the host computer to give the d-axis current (the current size is determined according to the actual situation) when the motor is in a stationary state. At this time, the host computer can read the motor zero position value, which is the initial zero position value of the motor, which needs to be adjusted according to the speed later.

[0044] Fourth step: under the condition of sufficient weak magnetic voltage margin of the motor (generally about 5% of the motor bus voltage, the value is taken according to the actual algorithm requirement), the dynamometer drags the motor to rotate at a set speed step, and when the speed reaches the set speed and stabilizes for about 2s, the bench feedback torque value can be read at this time. Open the previously measured electric no-load torque data, and adjust the zero position value to the corresponding speed under the no-load torque close to the no-load torque.

[0045] Fifth step: the dynamometer continues to drag the motor to rotate at a set speed step, and the zero position value is adjusted by repeating the fourth step until the motor maximum speed threshold, at which time the accurate zero position value is obtained, and the dynamometer speed is reduced to zero.

[0046] S2, zero torque current table calibration: the dynamometer controls the motor speed, the controller host computer selects the current control mode, and the zero torque current table is calibrated at the corresponding speed according to the calibrated motor zero position;

[0047] The zero-torque current table calibration of step S2 is based on the completion of the motor zero calibration. The motor is driven to a set speed by the dynamometer bench. The host computer of the controller selects the current mode to ensure sufficient weak magnetic voltage margin. The d-axis and q-axis currents are calibrated to make the bench feedback torque fluctuate around zero. The corresponding speed, d-axis and q-axis currents are recorded. After the calibration at one speed is completed, the motor is continuously driven at the set speed step by the dynamometer. The above steps are repeated until the motor reaches the maximum speed. The corresponding speed, d-axis and q-axis current data are summarized.

[0048] That is, the zero-torque current table calibration in step S1 is based on the motor zero calibration. The starting state of the motor and the bench is maintained. The current table calibration is performed at zero torque at the corresponding speed. The bench feedback torque can be zero when the controller sends a zero torque command. Referring to Figure 4 The state of the bench device is maintained as described above, which is not described here. In the case of sufficient weak magnetic voltage margin (given reverse d current, the voltage margin is generally about 5% of the motor bus voltage, which is selected according to the actual algorithm), the motor is driven to a set speed by the dynamometer at a set speed step. At this time, the bench feedback torque is negative. The current mode is selected in the calibration host computer. The d-axis and q-axis current commands are sent according to the actual torque to make the bench feedback torque zero. The given d-axis and q-axis currents and the speed are recorded. The calibration at this speed is completed. The motor is continuously driven at the set speed step by the dynamometer. The above calibration steps are repeated until the motor reaches the maximum speed. The recorded speed, d-axis and q-axis current given values are summarized.

[0049] S3, no-load loss test: The motor speed is controlled by the dynamometer. The controller host computer selects the torque control mode and gives a zero motor torque command for no-load loss test. The bench records the test data and calculates the no-load loss value.

[0050] In step S3, the no-load loss test is performed. After the motor torque command is given as zero, the motor is driven by the dynamometer at a set speed step. The motor speed, motor torque, bus voltage and bus current are recorded when the torque range is around zero. That is, the torque mode is selected in the calibration host computer or the bench host computer. The motor is driven to a set speed by the dynamometer at a set speed step. The bench feedback torque is observed after 2s of stabilization. The motor is continuously driven at the set speed step by the dynamometer. The above calibration steps are repeated until the motor reaches the maximum speed. The recorded speed, torque, bus voltage and bus current values are summarized.

[0051] The motor no-load loss is calculated according to the data recorded by the bench:

[0052] Motor speed x motor torque / 9550 = motor mechanical power

[0053] Bus voltage x bus current = electric power;

[0054] Motor no-load loss = motor mechanical power + electric power.

[0055] According to the above calculation method, it can be seen that there are two main factors affecting the motor no-load loss: motor torque and bus current. In the case of constant motor speed, the greater the motor output torque and the greater the bus current, the greater the motor no-load loss.

[0056] S4, analyze the measured no-load loss data, and calibrate the motor zero position and no-load current meter according to the specific data performance and input no-load loss index, so as to reduce the no-load loss.

[0057] The step S4 is to reduce the motor no-load loss by calibration, analyze the measured no-load loss data: the motor torque, motor power, bus current and bus power at different motor speeds, and evaluate whether the test results meet the requirements according to the customer input no-load loss standard. If the requirements are not met, reduce the actual torque of the motor at zero torque command and reduce the bus current to calibrate the motor zero position and no-load current meter, so as to reduce the no-load loss. That is, according to the no-load loss data obtained by step S3, observe the motor power and bus power curve, analyze the performance of no-load loss in the full speed range, evaluate whether the actual torque of the motor (whether around zero) and the bus power (large value, trend is not flat) are abnormal, and then implement the reduction measures.

[0058] The first measure is to reduce the no-load loss by motor zero position calibration: start the dynamometer to drive the motor to rotate, adjust the motor zero position according to the measured no-load torque to make it accurate and reduce the error, avoid the current component on the d-axis or q-axis due to zero position error, and reduce the no-load loss from the motor torque aspect.

[0059] The second measure is to reduce the no-load loss by no-load current meter calibration: observe the real-time field weakening voltage margin, first reduce the d-axis current as much as possible under the condition of sufficient field weakening voltage margin, adjust the q-axis current, and observe whether the motor torque is zero to avoid excessive current loss, so as to reduce the bus DC current and further reduce the motor no-load loss.

Claims

1. Method for testing the no-load losses of an electric machine, characterized in that, The method comprises the following steps: S1, motor zero calibration, including no-load torque test and motor zero calibration; the motor zero calibration comprises: making the bench feedback torque be the measured motor no-load torque, connecting the three-phase lines between the motor and the controller, the low-voltage line bundle of the controller, the low-voltage 12V and the high-voltage rated voltage on the controller, the current mode selected by the controller host computer, driving the motor to rotate to the set speed by the dynamometer, taking the measured no-load torque as the reference, giving the d-axis current, and adjusting the initial zero value under the condition that the motor weak magnetic margin is sufficient, so that the torque measured by the bench in the present state is more than 90% of the no-load torque; after the calibration at one speed is completed, the dynamometer continues to drive the motor to rotate at the set speed step, and the above steps are repeated until the motor speed is the maximum speed, so that the motor torque measured by the dynamometer at the motor zero position in the full speed range is the no-load torque; S2, zero torque current table calibration: the dynamometer controls the motor speed, the current control mode is selected by the controller host computer, and the zero torque current table calibration is performed at the corresponding speed according to the calibrated motor zero position; the zero torque current table calibration is based on the completion of the motor zero calibration, the motor is driven to rotate to the set speed by the dynamometer bench, the current mode is selected by the controller host computer, the d-axis and q-axis currents are calibrated to make the bench feedback motor torque fluctuate around zero under the condition that the motor weak magnetic margin is sufficient, and the corresponding speed, d-axis and q-axis currents are recorded; after the calibration at one speed is completed, the dynamometer continues to drive the motor to rotate at the set speed step, and the above steps are repeated until the motor speed is the maximum speed, and the corresponding speed, d-axis and q-axis current data are summarized; S3, no-load loss test: the dynamometer controls the motor speed, the torque control mode is selected by the controller host computer, the motor torque command is given as zero, the no-load loss test is performed, the test data are recorded by the bench, and the no-load loss value is calculated; S4, reducing the motor no-load loss by calibration, and analyzing the measured no-load loss data: the motor torque, motor power, bus current and bus power at different motor speeds, whether the test result meets the requirements according to the customer input no-load loss standard, if not, the motor zero calibration and the no-load current table calibration are performed from two aspects of reducing the actual torque of the motor at zero torque command and reducing the bus current to reduce the no-load loss.

2. The method of testing no-load losses of an electric machine according to claim 1, characterized in that, The no-load torque test in the step S1 comprises: disconnecting the three-phase connecting lines between the motor and the controller, driving the motor to rotate at the set speed step by the dynamometer bench, and rotating until the motor maximum speed, and measuring the torque of the motor in the no-load state at the corresponding speed.

3. The method of testing no-load losses of an electric machine according to claim 1, characterized in that, The test of the no-load loss in the step S3, after the motor torque command is given as zero, the dynamometer drives the motor to rotate at the set speed step, and the motor speed, motor torque, bus voltage and bus current are recorded by the bench when the torque range is around zero; The motor no-load loss is calculated according to the data recorded by the bench: Motor speed x motor torque / 9550= motor mechanical power; Bus voltage x bus current= electric power; Motor no-load loss= motor mechanical power+ electric power.

4. The method of testing no-load losses of an electric machine according to claim 1, characterized in that, The process of reducing the no-load loss by motor zero calibration is: starting the dynamometer to drive the motor to rotate, and adjusting the motor zero according to the measured no-load torque to make it accurate and reduce the error, so as to avoid the current component on the d-axis or q-axis due to the zero error, and reduce the no-load loss from the motor torque.

5. The method of testing no-load losses of an electric machine according to claim 1, characterized in that, The process of reducing the no-load loss by no-load current table calibration is: observing the real-time field weakening voltage margin, firstly reducing the d-axis current as much as possible under the condition of ensuring that the field weakening voltage margin is sufficient, adjusting the q-axis current, and observing whether the motor torque is zero, so as to avoid excessive current loss, thereby achieving the purpose of reducing the bus DC current, and further reducing the motor no-load loss.

6. The method of testing no-load losses of an electric machine according to claim 1, characterized in that, The motor is a permanent magnet synchronous motor.

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