Compensation method of permanent magnet synchronous motor angle sensor

Abstract

The invention discloses a compensation method for an angle sensor of a permanent magnet synchronous motor, and the method comprises the steps: collecting an original output signal of the angle sensor, and carrying out the electrical angle compensation of the original output signal, and obtaining an electrical angle parameter compensation value; performing mechanical angle compensation on the original output signal to obtain a resolver zero deflection angle and a mechanical angle parameter compensation value; compensating an original output signal by using the electrical angle parameter compensation value, the resolver zero deflection angle and the mechanical angle parameter compensation value, and taking the compensated signal as an angle input signal for closed-loop control of the permanent magnet synchronous motor; the original output signals comprise two sinusoidal signals and two cosine signals. The signal error of the permanent magnet synchronous motor angle sensor can be corrected, and the control precision of the motor is improved.

Description

Technical Field

[0001] The invention relates to the technical field of automobiles, and in particular to a compensation method for a permanent magnet synchronous motor angle sensor in an automobile steering gear component. Background Art

[0002] The ECU is equipped with an angle sensor (RPS) to detect the angle of the permanent magnet synchronous motor. By using the signal output value of the RPS, the angle value input in the high-precision closed-loop control of the permanent magnet synchronous motor is realized. Since the RPS will have errors during signal acquisition: such as DC noise in the signal acquisition circuit, which interferes with the signal amplitude, phase and offset, and at the same time, the mechanical errors caused by the RPS itself: such as manufacturing errors, installation errors, etc., the permanent magnet synchronous motor cannot obtain the required control accuracy. Summary of the invention

[0003] The technical problem to be solved by the present invention is how to provide a technical solution that can compensate for the signal error of the angle sensor of a permanent magnet synchronous motor.

[0004] In order to solve the above technical problems, the present invention provides a compensation method for a permanent magnet synchronous motor angle sensor, which collects the original output signal of the angle sensor, performs electrical angle compensation on the original output signal to obtain an electrical angle parameter compensation value, and performs mechanical angle compensation on the original output signal to obtain a resolver zero-position deviation angle and a mechanical angle parameter compensation value; the original output signal is compensated using the electrical angle parameter compensation value, the resolver zero-position deviation angle and the mechanical angle parameter compensation value, and the compensated signal is used as an angle input signal for closed-loop control of the permanent magnet synchronous motor; the original output signal includes two sine signals and two cosine signals.

[0005] Preferably, the sampling frequency for collecting the original output signal of the angle sensor is 100Ks / Samples.

[0006] Preferably, the method for electrical angle compensation comprises the following steps:

[0007] Step A1, performing pairwise difference on the original output signals to obtain a sine curve and a cosine curve before compensation;

[0008] Step A2, performing FFT transformation on the sine curve and the cosine curve to convert the time domain signal into a frequency domain signal;

[0009] Step A3, extracting the amplitude, phase angle, and offset information of the sine curve and cosine curve at all frequency domain orders;

[0010] Step A4, compensating the sine curve and cosine curve before compensation according to the amplitude, phase angle, and offset information to obtain the sine curve and cosine curve after compensation;

[0011] Step A5, comparing the preset standard sine curve and standard cosine curve with the compensated sine curve and cosine curve, if the data are consistent, the amplitude, phase angle, and offset information are used as electrical angle parameter compensation values.

[0012] Preferably, the method for electrical angle compensation further comprises: step A6, drawing a Lissajous circle and verifying the compensated sine curve and cosine curve.

[0013] Preferably, the method for obtaining the resolver zero-position deflection angle in the mechanical angle compensation comprises the following steps:

[0014] Step B1, building three coordinate models in the simulation tool;

[0015] Step B2, inputting the reference current of the d-axis and the q-axis through the PI current loop, and giving the rated vector angle value;

[0016] Step B3, controlling the opening and closing of the three-phase MOS through the SVPWM modulation model, and the motor rotor angle position observed in the observer is the resolver zero position deviation angle.

[0017] Preferably, through 6 electrical cycles, the average value of the resolver zero-position deviation angle calculated is used as the resolver zero-position deviation angle for final compensation.

[0018] Preferably, in step A3, the orders corresponding to low energy amplitudes with amplitudes less than 0.2 in the frequency domain sequence are eliminated.

[0019] The present invention can correct the signal error of the permanent magnet synchronous motor angle sensor and improve the control accuracy of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0021] Figure 1 This is a schematic diagram of the compensation method process of the permanent magnet synchronous motor angle sensor of Example 2;

[0022] Figure 2 The sinus spectrum diagram without logic processing and the sinus spectrum diagram after logic processing in Example 2;

[0023] Figure 3 Schematic diagram of amplitude and frequency data corresponding to Sinus in Amp2Ord and Amp4Ord in Example 2;

[0024] Figure 4 This is a schematic diagram of the waveform after the original 2nd and 4th order harmonics of Sinus are superimposed in Example 2;

[0025] Figure 5Schematic diagram of the waveform after Sinus compensation in Example 2;

[0026] Figure 6 Schematic diagram of comparison between the standard Sinus waveform and the compensated Sinus waveform in Example 2;

[0027] Figure 7 This is the Cosus spectrum diagram after logical processing in Example 2;

[0028] Figure 8 Schematic diagram of amplitude and frequency data corresponding to Cosus in Amp2Ord and Amp4Ord in Example 2;

[0029] Fig. 9 This is a schematic diagram of the waveform after the original 2nd and 4th order harmonics of Cosus are superimposed in Example 2;

[0030] Fig.10 Schematic diagram of the comparison between the standard Cosus waveform and the compensated Cosus waveform in Example 2;

[0031] Fig.11 Schematic diagram of comparison of Lissajous circles before and after compensation in Example 2;

[0032] Fig.12 is a schematic diagram of the stationary coordinate system ABC in Example 2;

[0033] Fig.13 Schematic diagram of the motor control model in Example 2;

[0034] Fig.14 Schematic diagram of the PI current loop model in Example 2;

[0035] Fig.15 Schematic diagram of the resolver zero-position deviation angle observed by RPS in Example 2. DETAILED DESCRIPTION

[0036] The following describes the implementation methods of the present invention through specific specific embodiments, and those skilled in the art can fully understand other advantages and technical effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through different specific implementation methods, and the details in this specification can also be applied based on different viewpoints, and various modifications or changes can be made without deviating from the overall design concept of the invention. It should be noted that the following embodiments and the features in the embodiments can be combined with each other in the absence of conflict. The following exemplary embodiments of the present invention can be implemented in a variety of different forms and should not be interpreted as being limited to the specific embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary specific embodiments to those skilled in the art.

[0037] Example 1

[0038] The present embodiment provides a compensation method for a permanent magnet synchronous motor angle sensor, which collects the original output signal of the angle sensor, performs electrical angle compensation on the original output signal to obtain an electrical angle parameter compensation value, and performs mechanical angle compensation on the original output signal to obtain a resolver zero-position deviation angle and a mechanical angle parameter compensation value; the original output signal is compensated using the electrical angle parameter compensation value, the resolver zero-position deviation angle and the mechanical angle parameter compensation value, and the compensated signal is used as the angle input signal for closed-loop control of the permanent magnet synchronous motor.

[0039] Specifically, this embodiment collects electrical signals from the output end of the RPS, and transmits the collected data to the electrical angle compensation model in Matlab to correct the signal amplitude, phase and offset. Taking the compensated electrical signal as a reference, the original signal value and the motor rotor angle position observation value are transmitted to the mechanical angle compensation model in Matlab to correct the angle deviation, signal amplitude, phase and offset. The compensation model built in Matlab improves the accuracy of the RPS output signal, thereby improving the control accuracy of the motor.

[0040] In the specific implementation process, the permanent magnet synchronous motor is controlled by IPC, and the RPS in the ECU senses the change of magnetic field and outputs four sine / cosine signals respectively: After the signal passes through the connector and the measuring unit, it is used as the input of the compensation model in the IPC for data calculation, and finally the compensation value and the data processing results of each step are output. Because the hardware device has a universal structure and construction method, the present invention does not describe its hardware structure.

[0041] The method of electrical angle compensation comprises the following steps:

[0042] Step A1, performing pairwise difference on the original output signals to obtain a sine curve and a cosine curve before compensation;

[0043] Step A2, performing FFT transformation on the sine curve and the cosine curve to convert the time domain signal into a frequency domain signal;

[0044] Step A3, extracting the amplitude, phase angle, and offset information of the sine curve and cosine curve at all frequency domain orders;

[0045] Step A4, compensating the sine curve and cosine curve before compensation according to the amplitude, phase angle, and offset information to obtain the sine curve and cosine curve after compensation;

[0046] Step A5, comparing the preset standard sine curve and standard cosine curve with the compensated sine curve and cosine curve, and if the data are consistent, using the amplitude, phase angle, and offset information as electrical angle parameter compensation values;

[0047] Step A6, draw a Lissajous circle and verify the compensated sine curve and cosine curve.

[0048] The method for obtaining the resolver zero position deflection angle in mechanical angle compensation comprises the following steps:

[0049] Step B1, building three coordinate models in the simulation tool;

[0050] Step B2, inputting the reference current of the d-axis and the q-axis through the PI current loop, and giving the rated vector angle value;

[0051] Step B3, controlling the opening and closing of the three-phase MOS through the SVPWM modulation model, and the motor rotor angle position observed in the observer is the resolver zero position deviation angle.

[0052] Example 2

[0053] This embodiment uses a specific example to illustrate the embodiment 1.

[0054] Figure 1 The complete process of the compensation method for the permanent magnet synchronous motor angle sensor of this embodiment is shown.

[0055] In the signal acquisition step, 80244 data points of the four RPS electrical signals were collected at rpm = 200 and the sampling rate was 100Ks / S. The collected RPS data were imported into the electrical angle compensation model in Matlab: Read the collected data; Get Cos - Data; Get Cos + Get the data of Sin - Get the data of Sin + data.

[0056] The process of electrical angle compensation is as follows:

[0057] Step A1, performing pairwise difference analysis on the original output signals,

[0058] That is: Sinus=Sin_P-Sin_N; Cosus=Cos_P-Cos_N;

[0059] With respect to the specific process of steps A2 to A5, the sine curve Sinus and the cosine curve Cosus are respectively described below.

[0060] The process of implementing steps A2 to A5 for the sine curve Sinus is as follows:

[0061] 1. Perform fast Fourier transform on Sinus and define the time domain sampling signal sinus: set the sampling frequency of the Sinus signal, set the sampling time interval of the Sinus signal, set the length of the Sinus sampling signal, define the time point t of signal sampling, transpose the row vector into a column vector, perform fast Fourier transform on the time domain sampling signal sinus, correct the amplitude of the frequency domain sequence, so that the result of the FFT transform has a clear physical meaning; extract the positive frequency part in sinus, and merge the negative frequency part in sinus into the positive frequency.

[0062] 2. Define the frequency scale corresponding to the sinus sampling signal: calculate the frequency interval, calculate the frequency scale, and transpose the row vector f into a column vector.

[0063] 3. Calculate the amplitude and phase angle of the frequency domain sequence Y: Calculate the amplitude of the frequency domain sequence sinus, calculate the phase angle of the frequency domain sequence sinus - radians, phase angle data processing logic, amplitude data processing logic, phase angle data processing logic is: eliminate the orders corresponding to the low energy amplitudes with amplitudes less than 0.2 in the frequency domain sequence, as shown in Figure 2.

[0064] 4. Get the amplitude and phase angle data corresponding to sinus in Amp2Ord and Amp4Ord, such as Figure 3 shown.

[0065] 5. Calculate the offset value of sinus: offset = (max(sinus) + min(sinus)) / 2; the result is: -0.0064.

[0066] 6. According to step 4 and step 5, the functional relationship of sinus in Amp2Ord (second order) and Amp4Ord (fourth order) is obtained: Sinus = 0.8237*sin(200 / 60*2*pi*t+0.5669)+0.2113*sin(200 / 60*2*pi*t-2.9283)-0.0064; make the above waveform diagram before compensation, as shown in Figure 4 Shown:

[0067] Sin=0.8237*sin(200 / 60*2*pi*t+0.5669)+0.2113*sin(00 / 60*2*pi*t-2.9283)-0.0064.

[0068] 7. Compensate the amplitude, phase angle and offset of the sinus function to obtain the function expression of sinus:

[0069] Sinus_Compensation=-0.8*sin(200 / 60*2*pi*t)-0.2*sin(200 / 60*2*pi*t) makes the waveform after the above compensation, such as Figure 5 As shown: Sin_Compensation =

[0070] -0.8*sin(200 / 60*2*pi*t)-0.2*sin(200 / 60*2*pi*t)

[0071] 8. Compare the output defined standard sinus data waveform with the compensated sinus data waveform, such as Figure 6 As shown in the waveform results, it can be seen that after the electrical angle compensation model, the compensated data is consistent with the standard data, and the compensation calculation of data amplitude, phase angle and offset is completed.

[0072] The Cosus data is processed in the same way as the Sinus data. The Cosus spectrum after logical processing is as follows: Figure 7 shown.

[0073] The amplitude and phase angle data corresponding to Cosus in Amp2Ord and Amp4Ord are as follows Figure 8 shown.

[0074] Calculate the offset value of Cosus: offset = (max (Cosus) + min (Cosus)) / 2; the result is: -0.0030

[0075] The functional relationship between Cosus in Amp2Ord (second order) and Amp4Ord (fourth order) is:

[0076] Cosus = 0.8759*cos(200 / 60*2*pi*t+2.0319)+0.1434*sin(200 / 60*2*pi*t-0.5762)-0.0030; Make the waveform diagram before compensation as shown above Fig. 9 shown.

[0077] The cosus function is compensated for amplitude, phase angle and offset, and the function expression of cosus is obtained as follows:

[0078] Cosus_Compensation=-0.87*cos(200 / 60*2*pi*t)-0.13*cos(200 / 60*2*pi*t);

[0079] The waveform after the above compensation is compared with the standard cosus waveform. Fig.10 shown.

[0080] Step A6, drawing the Lissajous circle is as follows:

[0081] The Lissajous circle is drawn with cosus as the horizontal coordinate and sinus as the vertical coordinate, such as Fig.11 As shown. The compensated Lissajous circle is a circle with a radius of 1 and a center at (0,0). Therefore, the angle calculation through the compensated sinus and cosus function curves is more accurate: the angle value calculation is:

[0082] The process of mechanical angle compensation of the original output signal is as follows:

[0083] Take the A axis in the three-phase stationary coordinate system of the permanent magnet synchronous motor as the motor zero position, such as Fig.12 As shown;

[0084] Solve for the resolver zero-position deviation angle δ: In the simulation tool Simulink, make the motor unloaded, give a DC bus voltage of 12V, control the U-phase current to 5A, and the V-phase and W-phase currents to corresponding negative values ​​(and reach the sector 100 state, corresponding to the U-phase high-side MOS closed, the V / W high-side MOS disconnected, and the V / W low-side MOS closed, that is, V_β of the β-axis = 0), then the motor rotor moves to a fixed position, that is, the A-axis coincides with the d-axis, and the resolver reading angle is the resolver zero-position deviation angle.

[0085] like Fig.13 Shown is the FOC control model block diagram (motor control model diagram) built in Simulink.

[0086] Given a fixed angle current value of 0° for the current vector in the PI current loop, 0A for the d-axis reference current, and 5A for the q-axis reference current. Fig.14 shown.

[0087] Determine the motor parameters used:

[0088] Resistance R = 0.6Ω, inductance L = 1.4e-3H, and the rotor type is surface mount.

[0089] Through the above parameters, the PI current loop proportional parameters and integral parameters of the d and q axes of the surface-mounted motor are determined:

[0090] K pd =K pq =2πR=3.77;

[0091]

[0092] like Fig.15 As shown in the figure, the angle between the motor rotor and the A axis observed by the RPS is the resolver zero position deviation angle:

[0093]

[0094] δ=360°-θ=244.26°

[0095] Because of mechanical tolerances, the angle offset measured for each electrical cycle of a mechanical rotation may be different, so the calibration must be repeated through 6 electrical cycles and the average value of the resolver zero deviation angle must be calculated.

[0096] The method for obtaining the mechanical angle parameter compensation value may be the same as the method for obtaining the electrical angle parameter compensation value.

[0097] Compared with the prior art, this embodiment has the following beneficial technical effects:

[0098] 1. The existing technical implementation scheme uses the integral operation of the D parameter in the current loop, but there is electrical noise in the three-phase current acquisition process. At the same time, the current PID control module needs to be adjusted manually, which is not easy to control in the actual process. The present invention effectively filters out the electrical noise in the three-phase current through electrical angle module compensation, and at the same time eliminates the complex adjustment process of PID control, and uses simple coordinate transformation and algorithm calculation to obtain the current mechanical angle difference. Therefore, there is no need for highly concentrated manual operation, and more efficient automatic compensation is achieved, and the compensation process is easier to control;

[0099] 2. The compensation parameter calculation accuracy of the present invention is higher, the steps can be traced back, and the accuracy is high;

[0100] 3. The compensation model is more extensible and modifiable. It only needs to change the corresponding three standard parameters: amplitude, phase angle, offset, and has high operability;

[0101] 4. It can be used for PowerPack of different models B3 / C3 / C6, with a wide range of uses.

[0102] The present invention has been described in detail above through specific implementation modes and embodiments, but these do not constitute limitations of the present invention. Without departing from the principles of the present invention, those skilled in the art may also make many variations and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. A compensation method for a permanent magnet synchronous motor angle sensor, characterized in that: The original output signal of the angle sensor is collected, and electrical angle compensation is performed on the original output signal to obtain an electrical angle parameter compensation value, and mechanical angle compensation is performed on the original output signal to obtain a resolver zero-position deviation angle and a mechanical angle parameter compensation value; the original output signal is compensated using the electrical angle parameter compensation value, the resolver zero-position deviation angle and the mechanical angle parameter compensation value, and the compensated signal is used as an angle input signal for closed-loop control of a permanent magnet synchronous motor; the original output signal includes two sine signals and two cosine signals.

2. The compensation method for the permanent magnet synchronous motor angle sensor according to claim 1, characterized in that: The sampling frequency for collecting the original output signal of the angle sensor is 100Ks / Samples.

3. The compensation method for the permanent magnet synchronous motor angle sensor according to claim 1, characterized in that: The method for electrical angle compensation comprises the following steps: Step A1, performing pairwise difference on the original output signals to obtain a sine curve and a cosine curve before compensation; Step A2, performing FFT transformation on the sine curve and the cosine curve to convert the time domain signal into a frequency domain signal; Step A3, extracting the amplitude, phase angle, and offset information of the sine curve and cosine curve at all frequency domain orders; Step A4, compensating the sine curve and cosine curve before compensation according to the amplitude, phase angle, and offset information to obtain the sine curve and cosine curve after compensation; Step A5, comparing the preset standard sine curve and standard cosine curve with the compensated sine curve and cosine curve, if the data are consistent, the amplitude, phase angle, and offset information are used as electrical angle parameter compensation values.

4. The compensation method for the permanent magnet synchronous motor angle sensor according to claim 3, characterized in that: The method for electrical angle compensation also includes: step A6, drawing a Lissajous circle and verifying the compensated sine curve and cosine curve.

5. The compensation method for the permanent magnet synchronous motor angle sensor according to claim 1, characterized in that: The method for obtaining the resolver zero position deflection angle in the mechanical angle compensation comprises the following steps: Step B1, building three coordinate models in the simulation tool; Step B2, inputting the reference current of the d-axis and the q-axis through the PI current loop, and giving the rated vector angle value; Step B3, controlling the opening and closing of the three-phase MOS through the SVPWM modulation model, and the motor rotor angle position observed in the observer is the resolver zero position deviation angle.

6. The compensation method for the permanent magnet synchronous motor angle sensor according to claim 5, characterized in that: After 6 electrical cycles, the average value of the resolver zero-position deviation angle calculated is used as the resolver zero-position deviation angle for final compensation.

7. The compensation method for the permanent magnet synchronous motor angle sensor according to claim 3, characterized in that: In step A3, the orders corresponding to the low energy amplitudes with amplitudes less than 0.2 in the frequency domain sequence are eliminated.

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