Orthogonal high-frequency injection control method for permanent magnet synchronous motor of hydrogen circulating pump

Abstract

The invention relates to the technical field of permanent magnet synchronous motor control, in particular to an orthogonal high-frequency injection control method of a hydrogen circulating pump permanent magnet synchronous motor. Comprising the following steps: S1, injecting high-frequency pulse voltage to a d axis and a q axis of a virtual coordinate system, collecting a three-phase current signal generated by a circulating pump motor end, and generating d-axis current and q-axis current; s2, enabling the d-axis current and the q-axis current to pass through a high-pass filter; s3, building a Luenberger observer and an enhanced phase-locked loop model, and performing amplitude separation and extraction on the d-axis current and the q-axis current; s4, recombining the d-axis amplitude signal and the q-axis amplitude signal decomposed in the step S3; s5, establishing a phase-locked loop, and converting the virtual angle into an electrical angle and a speed signal; and S6, converting the number of pole pairs of the motor according to the electrical angle and the speed signal. According to the orthogonal high-frequency injection control method of the hydrogen circulating pump permanent magnet synchronous motor, dependence on motor parameters can be reduced, and the estimation precision and the operation stability of the permanent magnet synchronous motor are improved.

Description

Technical Field

[0001] The invention relates to the technical field of permanent magnet synchronous motor control, and in particular to an orthogonal high frequency injection control method for a permanent magnet synchronous motor of a hydrogen circulation pump. Background Art

[0002] Permanent magnet synchronous motor, abbreviated as "PMSM", is a motor that works on the principle of electromagnetic induction. When the permanent magnet synchronous motor is running, the observer algorithm used in medium and high speed operation is different from the algorithm used in the low-speed segment. Most permanent magnet synchronous motors start in an open loop in the starting segment and then switch to closed-loop control in the high-speed segment. However, this will result in poor stability due to the lack of a closed-loop form in the low-speed segment.

[0003] The current high-frequency injection method usually injects a high-frequency low voltage into the d-axis, then reads the current of the d-axis for processing and extracts speed and angle related information. However, this method relies on motor parameters to a certain extent for calculation, and when the high-frequency signal contains relatively more stray signals, the estimation accuracy is low, so the permanent magnet synchronous motor still has instability. Summary of the invention

[0004] The present invention aims to provide an orthogonal high-frequency injection control method for a permanent magnet synchronous motor of a hydrogen circulation pump, so as to reduce the dependence on motor parameters, improve the estimation accuracy and the stability of the operation of the permanent magnet synchronous motor.

[0005] To achieve the above object, the present invention adopts the following technical solution: an orthogonal high frequency injection control method for a permanent magnet synchronous motor of a hydrogen circulation pump, comprising the following steps:

[0006] S1, injecting high-frequency pulse voltage into the d-axis and q-axis of the virtual coordinate system, the high-frequency pulse voltage injected into the d-axis and q-axis has equal amplitude and a phase difference of 90°, and collecting the three-phase current signal generated by the motor end of the circulating pump and performing coordinate change to generate d-axis current and q-axis current;

[0007] S2, filtering the d-axis current and the q-axis current to the same extent through a high-pass filter;

[0008] S3. Build the Lumberg observer and enhanced phase-locked loop model, and use formula (1) to separate and extract the amplitude of the d-axis current:

[0009] i dh =i dh1 *cos(w0*t)+i dh2 *sin(w0*t) (1)

[0010] Formula (2) is used to separate and extract the amplitude of the q-axis current:

[0011] i qh =iqh1 *cos(w0*t)+i qh2 *sin(w0*t) (2)

[0012] in:

[0013]

[0014]

[0015] S4, using (7) and (8) to reorganize the d-axis amplitude signal and q-axis amplitude signal decomposed in S3, and establish virtual coordinates for unitization and orthogonalization:

[0016] I1=i dh1 +i qh2 (7)

[0017] I2=-i dh2 +i qh1 (8)

[0018] S5. Use formula (9) to establish a phase-locked loop and convert the virtual angle into the electrical angle and speed signal of the motor:

[0019]

[0020] S6. Convert the electrical angle and speed signal into the number of motor pole pairs, and then output it as a control signal through the control of the motor's speed loop and current loop.

[0021] Where γ is the difference of the phase-locked loop; α is the follow angle of the phase-locked loop, which is the result obtained after γ passes through the PID algorithm; I1 and I2 are intermediate temporary variables used to establish virtual angles later; Ld is the direct-axis inductance of the motor, Lq is the quadrature-axis inductance of the motor; i is the amplitude component of each current, which is also an intermediate variable; W0 is the high-frequency injection angular frequency, t is the time, △

[0022] θ is the virtual angle (the difference between the estimated axis and the actual axis).

[0023] In step S4, when convergence occurs, since cos(2Δθ) is approximately a constant of 1, this solution introduces variables and substitutes them into the above formula with a constant of 1 for calculation, which are:

[0024] The beneficial effects of this program are:

[0025] 1. This solution adopts the method of injecting voltage into the d-axis and q-axis at the same time and analyzing the current of the d-axis and q-axis at the same time. Compared with the traditional method of injecting voltage into the d-axis only and analyzing the current, the phase difference of the high-frequency pulse voltage injected into the d-axis and q-axis in this solution is 90°, and its orthogonal injection method is more conducive to removing interference, making the calculation and control more accurate. Secondly, because the orthogonalization is performed first, S5 needs to convert the virtual angle into the mean square in the calculation of the electrical angle and speed signal of the motor, so it can be normalized and reduce interference in the subsequent calculation. Therefore, the control method of this scheme can better perform spurious removal and analysis, making the motor operation more stable and less prone to instability, thereby improving the reliability of operation.

[0026] 2. At the same time, the orthogonalization process reduces its dependence on motor parameters, making it unnecessary to rely too much on the accuracy of measuring instruments during R&D and migration, and enhancing the versatility of the code, reducing R&D costs; it also greatly enhances the parameter errors in the motor manufacturing process, lowering the technical threshold for motor production.

[0027] 3. The traditional method of injecting high-frequency pulse voltage only into the d-axis may cause startup failure. Since it is generally believed in the field that the method of injecting high-frequency pulse voltage into the d-axis and q-axis for control at the same time will lead to a sharp increase in the amount of calculation, greater requirements for control components, and higher control costs. The time consumed by restarting is also within an acceptable range, so the general operation after a startup failure is to restart directly. The inventor accidentally discovered that when injecting orthogonal high-frequency pulse voltages into the d-axis and q-axis, the amount of calculation is much less than simply injecting high-frequency pulse voltages into the d-axis and q-axis. The amount of calculation of this solution does not require the use of components with better performance and higher costs, so the control cost will not increase significantly. However, after adopting the control method of this solution, the situation of control failure is sharply reduced, and it has better anti-interference ability.

[0028] Furthermore, S1 first generates d-axis voltage and q-axis voltage, and then uses formula (10) and cooperates with the inverter bridge module to output a sine wave:

[0029] Udin=Um*sin(w0*t),Uqin=Um*cos(w0*t) (10)

[0030] And use it as a high-frequency pulse voltage injected into the d-axis and q-axis.

[0031] The beneficial effects of this scheme are: the control method of this scheme has strong anti-interference ability and is not dependent on motor parameters.

[0032] Furthermore, the cut-off frequency of the high-pass filter used by S2 is 1 / 2.

[0033] Furthermore, a fourth-order phase-locked loop is established in S5.

[0034] The beneficial effect of this solution is that the control method in this solution enables the permanent magnet synchronous motor to have better acceleration followability.

[0035] Furthermore, after filtering the d-axis current and the q-axis current, S2 enters a notch filter to purify and separate the amplitude signal.

[0036] The beneficial effect of this solution is that the low-frequency signal can be further removed by the notch filter, thereby improving the accuracy of the calculation in S3-S5, thereby performing more accurate control. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following is further described in detail through specific implementation methods:

[0039] Example

[0040] The present invention discloses an orthogonal high frequency injection control method for a permanent magnet synchronous motor of a hydrogen circulation pump, such as Figure 1 As shown, the following steps are included:

[0041] S1. Generate d-axis voltage and q-axis voltage. Use formula (10) and cooperate with the inverter bridge module to output a sine wave as a high-frequency pulse voltage to the d-axis and q-axis of the virtual coordinate system. The high-frequency pulse voltage injected into the d-axis and q-axis has the same amplitude and a phase difference of 90°. Collect the three-phase current signal generated by the circulating pump motor end and perform coordinate changes to generate the d-axis current and q-axis current.

[0042] Udin=Um*sin(w0*t), Uqin=Um*cos(w0*t) (10);

[0043] S2, filtering the d-axis current and the q-axis current to the same extent through a high-pass filter, and then entering a notch filter to purify and separate the amplitude signal; specifically, a high-pass filter with a cutoff frequency of 1 / 2 is selected, and in actual implementation, a high-pass filter with other cutoff frequencies can also be used as long as the low-frequency signal can be filtered out;

[0044] S3, build the Lumberg observer and enhanced phase-locked loop model, and use (1) to separate and extract the amplitude of the d-axis current:

[0045] i dh =i dh1 *cos(w0*t)+i dh2 *sin(w0*t) (1)

[0046] Formula (2) is used to separate and extract the amplitude of the q-axis current:

[0047] i qh =i qh1 *cos(w0*t)+i qh2 *sin(w0*t) (2)

[0048] in:

[0049]

[0050] S4. Use (7) and (8) to reorganize the d-axis amplitude signal and q-axis amplitude signal decomposed in S3, and establish virtual coordinates for unitization and orthogonalization: I1 = i dh1 +i qh2 (7)

[0051] I2=-i dh2 +i qh1 (8);

[0052] S5. Use (9) to establish a fourth-order phase-locked loop and convert the virtual angle into the electrical angle and speed signal of the motor:

[0053]

[0054] S6. Convert the electrical angle and speed signal into the number of motor pole pairs, and then output it as a control signal through the control of the motor's speed loop and current loop.

[0055] The control method of this embodiment is implemented using a control structure, which includes a high-frequency voltage generating module, a filter, a notch filter, an observer, a virtual angle module and a fourth-order phase-locked loop. The filter, notch filter, observer, virtual angle module and fourth-order phase-locked loop used in this embodiment are all existing technologies and will not be repeated in this embodiment.

[0056] The high-frequency voltage generation module enables the MCU to generate an estimated d-axis voltage and q-axis voltage and output them to the motor of the circulating pump in step S1; the filter and the notch filter perform stray signal removal processing on the signal after the coordinate transformation of the three-phase current of the motor in step S2; the observer module separates the required amplitude signal in the current in step S3. Specifically, in this embodiment, the EPLL enhanced phase-locked loop method can achieve better results; the virtual angle module establishes a virtual coordinate axis after orthogonal processing of the amplitude signal to reduce errors; the fourth-order phase-locked loop converts the virtual angle into the actual angle and speed required by the motor in step S5.

[0057] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for controlling orthogonal high frequency injection of a permanent magnet synchronous motor of a hydrogen circulation pump, characterized in that: The following steps are involved: S1, injecting high-frequency pulse voltage into the d-axis and q-axis of the virtual coordinate system, the high-frequency pulse voltage injected into the d-axis and q-axis has equal amplitude and a phase difference of 90°, and collecting the three-phase current signal generated by the motor end of the circulating pump and performing coordinate change to generate d-axis current and q-axis current; S2, filtering the d-axis current and the q-axis current to the same extent through a high-pass filter; S3. Build the Lumberg observer and enhanced phase-locked loop model, and use formula (1) to separate and extract the amplitude of the d-axis current: i dh =i dh1 *cos(w0*t)+i dh2 *sin(w0*t) (1) Formula (2) is used to separate and extract the amplitude of the q-axis current: i qh =i qh1 *cos(w0*t)+i qh2 *sin(w0*t) (2) in: S4. Use formula (7) and formula (8) to reorganize the d-axis amplitude signal and q-axis amplitude signal decomposed by S3, and establish virtual coordinates for unitization and orthogonalization: I1=i dh1 +i qh2 (7) I2=-i dh2 +i qh1 (8) S5. Use formula (9) to establish a phase-locked loop and convert the virtual angle into the electrical angle and speed signal of the motor: S6. Convert the electrical angle and speed signal into the number of motor pole pairs, and then output it as a control signal through the control of the motor's speed loop and current loop.

2. The orthogonal high frequency injection control method of the permanent magnet synchronous motor of the hydrogen circulation pump according to claim 3 is characterized in that: S1 first generates d-axis voltage and q-axis voltage, and then uses formula (10) to cooperate with the inverter bridge module to output a sine wave: Udin=Um*sin(w0*t),Uqin=Um*cos(w0*t) (10) And use it as a high-frequency pulse voltage injected into the d-axis and q-axis.

3. The orthogonal high frequency injection control method of the permanent magnet synchronous motor of the hydrogen circulation pump according to claim 1 is characterized in that: The cutoff frequency of the high-pass filter used in S2 is 1 / 2.

4. The orthogonal high frequency injection control method of the permanent magnet synchronous motor of the hydrogen circulation pump according to claim 1 is characterized in that: A fourth-order phase-locked loop is established in S5.

5. The orthogonal high frequency injection control method of the permanent magnet synchronous motor of the hydrogen circulation pump according to claim 1, characterized in that: After filtering the d-axis current and the q-axis current, S2 enters the notch filter to purify and separate the amplitude signal.

Images