A PI parameter impact analysis method and system

Abstract

The invention discloses a PI parameter influence analysis method and system, which relates to the technical field of motor design, and comprises the following steps: receiving the maximum value and minimum value of the H-bridge output voltage when the excitation winding of the motor is excited by the H-bridge full bridge; making a difference between the maximum value of the H-bridge output voltage and the minimum value of the H-bridge output voltage to obtain the peak-to-peak value of the excitation winding induced pulsating voltage, and the peak-to-peak value of the excitation winding induced pulsating voltage is independent of the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the excitation winding PI controller; using the peak-to-peak value of the excitation winding induced pulsating voltage and the PI parameters to calculate the modulation wave of the H-bridge; superimposing multiple harmonics on the modulation wave of the H-bridge as a DC component to obtain the H-bridge output voltage, subtracting the excitation winding resistance voltage drop from the H-bridge output voltage to obtain the excitation winding induced pulsating voltage, and achieving the influence effect of the PI parameters on the excitation winding induced pulsating voltage by correlating the excitation winding induced pulsating voltage with the PI parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of motor design, and in particular to a PI parameter influence analysis method and system. Background Art

[0002] Rare earth permanent magnet synchronous motors have been widely used in recent years because they omit the excitation system on the rotor, and their rotor robustness is high. Coupled with their high torque density, they are widely used. However, permanent magnet motors cannot work normally at high temperatures due to the high-temperature demagnetization characteristics of permanent magnets. In addition, due to the widespread application of permanent magnet motors in recent years, the demand for rare earth permanent magnet materials has been increasing, and there may even be a situation where supply exceeds demand. The electrically excited synchronous motor replaces the permanent magnet with an excitation system to solve the above problems.

[0003] As an electrically excited synchronous motor, the electric excitation magnetic field modulation motor has both the excitation winding and the armature winding located on the stator, which greatly improves the robustness of the rotor and enables it to be used in aerospace applications where high robustness of the motor is required. However, since the rotor of the electric excitation magnetic field modulation motor is a double salient pole structure, its air gap magnetic flux distribution is extremely uneven, resulting in a large excitation winding induced pulsating voltage, which has a negative impact on the control of the motor excitation winding.

[0004] The analysis and suppression of the induced pulsating voltage of the excitation winding under ideal current source excitation has been widely studied, but the generation mechanism and modeling of the induced pulsating voltage of the excitation winding under PWM excitation have not been studied in depth by scholars. However, PWM excitation will introduce high-frequency harmonics into the input voltage of the excitation winding. These harmonics have a great influence on the induced pulsating voltage of the excitation winding and cannot be ignored. The study of the induced pulsating voltage of the excitation winding under PWM excitation is of great significance. Summary of the invention

[0005] In order to solve the deficiencies mentioned in the above background technology, the object of the present invention is to provide a PI parameter influence analysis method and system, which can suppress the induced pulsating voltage of the excitation winding.

[0006] The purpose of the present invention can be achieved by the following technical solution: a PI parameter influence analysis method, the method comprising the following steps:

[0007] The maximum and minimum values ​​of the H-bridge output voltage when the field winding of the receiving motor is excited by the H-bridge full bridge;

[0008] The maximum value of the H-bridge output voltage is subtracted from the minimum value of the H-bridge output voltage to obtain the peak-to-peak value of the induced pulsating voltage of the excitation winding, and the peak-to-peak value of the induced pulsating voltage of the excitation winding is independent of the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the PI controller;

[0009] The modulation wave of the H bridge is calculated using the peak-to-peak value of the induced pulsating voltage of the excitation winding and the PI parameters;

[0010] The modulation wave of the H-bridge is superimposed with multiple harmonics as a DC component to obtain the H-bridge output voltage, and then the excitation winding resistance voltage drop is subtracted from the H-bridge output voltage to obtain the excitation winding induced pulsating voltage. The excitation winding induced pulsating voltage is related to the PI parameters, thereby achieving the effect of the PI parameters on the excitation winding induced pulsating voltage.

[0011] Preferably, the maximum value and the minimum value of the H-bridge output voltage are calculated by Kirchhoff's voltage law.

[0012] Preferably, the maximum value E of the H-bridge output voltage max The expression is:

[0013] E max =U dc -v load -v F

[0014] Among them, U dc is the DC bus voltage of the excitation winding, v load is the load voltage drop, v F is the conduction voltage drop of the power device;

[0015] The minimum value of the H-bridge output voltage E min The expression is:

[0016] E min =-U dc -v load -v F .

[0017] Preferably, the peak-to-peak value of the induced pulsating voltage of the excitation winding is pp =E max -E min =2U dc .

[0018] Preferably, the peak-to-peak value of the induced pulsating voltage of the excitation winding is pp and the excitation winding DC bus voltage U dc It is related to PI parameters.

[0019] Preferably, the calculation process of the modulation wave of the H-bridge is as follows:

[0020]

[0021] Among them, M f is the modulation wave of the H bridge, i dcref with i dc are the reference value and instantaneous value of the excitation winding current respectively; Kp With K i are the proportional coefficient and integral coefficient of the H-bridge PI controller, 2U dc =E pp is the peak-to-peak value of the induced pulsating voltage of the excitation winding.

[0022] Preferably, the modulation wave of the H bridge is a DC component superimposed LCM (N s ,N r ) / N r The Fourier pole expansion of the H-bridge output voltage is obtained when the subharmonic is obtained, where LCM is the lowest common multiple. The LCM (N s ,N r ) / N r The subharmonic amplitude will affect the LCM (N) in the H-bridge output voltage. s ,N r ) / N r The subharmonic amplitude affects the LCM (N) of the induced pulsating voltage of the excitation winding. s ,N r ) / N r Subharmonic amplitude.

[0023] Preferably, the LCM (N s ,N r ) / N r The first is the main harmonic order of the modulation wave of the H bridge.

[0024] Preferably, the H-bridge output voltage F mk The expression is as follows:

[0025]

[0026] Where m = 1, 2, 3, ..., N pe , k=0,±6,±12…are the harmonic orders of the carrier wave and the modulating wave respectively, N pe =LCM(N s ,N r ) / N r is the frequency of the field winding current, f PWM With f e are PWM frequency and motor base frequency, M0 and M pe are the DC component and N in the modulation wave respectively. pe The amplitude of the subharmonic component, θ1 is the phase of the modulated wave, J n (M pe mπ) represents the nth-order Bessel function;

[0027] From the above formula, the H-bridge output voltage F mk Medium peThe amplitude of the subharmonic is modulated by the H-bridge modulation wave M f Medium pe The amplitude of the subharmonic component M pe Therefore, the H-bridge output voltage F mk It is also affected by the PI parameters, and the H-bridge output voltage F mk Subtracting the resistance voltage drop of the excitation winding will give the induced pulsating voltage of the excitation winding, so the final induced pulsating voltage of the excitation winding is also affected by the PI parameters.

[0028] In another aspect of the present invention, in order to achieve the above object, a PI parameter impact analysis system is disclosed, comprising:

[0029] Receiving voltage module: used to receive the maximum and minimum values ​​of the H-bridge output voltage when the excitation winding of the motor is excited by the H-bridge full bridge;

[0030] Difference module: used to make a difference between the maximum value of the H-bridge output voltage and the minimum value of the H-bridge output voltage to obtain the peak-to-peak value of the induced pulsating voltage of the excitation winding, and the peak-to-peak value of the induced pulsating voltage of the excitation winding is independent of the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the PI controller of the excitation winding;

[0031] Calculation module: used to calculate the modulation wave of the H bridge using the peak-to-peak value of the induced pulsating voltage of the excitation winding and the PI parameters;

[0032] Output voltage module: used to convert the modulation wave of the H-bridge into a DC component and superimpose multiple harmonics to obtain the H-bridge output voltage, and then subtract the excitation winding resistance voltage drop from the H-bridge output voltage to obtain the excitation winding induced pulsating voltage. The excitation winding induced pulsating voltage is related to the PI parameters, thereby achieving the effect of the PI parameters on the excitation winding induced pulsating voltage.

[0033] Beneficial effects of the present invention:

[0034] The analysis method of the influence of PI parameters on the induced pulsating voltage of the excitation winding proposed in the present invention takes into account the PWM high-frequency harmonics. The analysis method of the influence of PI parameters on the induced pulsating voltage of the excitation winding proposed in the present invention gives the influence mechanism of PI parameters of the H-bridge PI controller on the induced pulsating voltage of the excitation winding under PWM excitation, which has a guiding role in suppressing the induced pulsating voltage of the excitation winding under PWM excitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 It is a schematic flow chart of the method of the present invention;

[0037] Figure 2 It is a schematic diagram of the principle structure of the system of the present invention;

[0038] Figure 3 It is a technical route for the analysis method of the influence of PI parameters on the induced pulsating voltage of the excitation winding.

[0039] Figure 4 The topology diagram of the 12-slot 10-pole electric excitation field modulation motor used in the present invention.

[0040] Figure 5 This is a diagram illustrating the size parameters of a 12-slot 10-pole electric excitation magnetic field modulation motor used in the present invention.

[0041] Figure 6 This is a schematic diagram of a 12-slot 10-pole electric excitation magnetic field modulation motor drive circuit used in the present invention.

[0042] Figure 7 It is a control block diagram of the H full bridge of the present invention.

[0043] Figure 8 The peak-to-peak value of the induced pulsating voltage of the motor excitation winding changes with the proportional coefficient K of the H-bridge PI controller when the magnetic field-circuit joint simulation is used in the present invention. p Change graph.

[0044] Fig. 9 The sixth harmonic of the H-bridge modulation wave and the sixth harmonic of the induced pulsating voltage of the excitation winding follow the proportional coefficient K of the H-bridge PI controller when the magnetic field-circuit joint simulation is used in the present invention. p Change graph.

[0045] Fig.10 The peak-to-peak value of the induced pulsating voltage of the motor excitation winding changes with the integral coefficient K of the H-bridge PI controller when the magnetic field-circuit joint simulation is used in the present invention. i Change graph.

[0046] Fig.11 The sixth harmonic of the H-bridge modulation wave and the sixth harmonic of the induced pulsating voltage of the excitation winding are calculated by the H-bridge PI controller integral coefficient K when the magnetic field-circuit joint simulation is used in the present invention. i Change graph. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] like Figure 1 As shown, a PI parameter impact analysis method comprises the following steps:

[0049] The maximum and minimum values ​​of the H-bridge output voltage when the field winding of the receiving motor is excited by the H-bridge full bridge;

[0050] The maximum value of the H-bridge output voltage is subtracted from the minimum value of the H-bridge output voltage to obtain the peak-to-peak value of the induced pulsating voltage of the excitation winding, and the peak-to-peak value of the induced pulsating voltage of the excitation winding is independent of the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the PI controller;

[0051] In this embodiment, the maximum value E of the H-bridge output voltage is obtained by Kirchhoff's voltage law. max The expression is:

[0052] E max =U dc -v load -v F (1)

[0053] Among them, U dc is the DC bus voltage of the excitation winding, v load is the load voltage drop, v F is the conduction voltage drop of the power device.

[0054] The minimum value of the H-bridge output voltage E min The expression is:

[0055] E min =-U dc -v load -v F (2)

[0056] From equations (1) and (2), we can get the peak-to-peak value of the induced pulsating voltage of the excitation winding: pp The expression is:

[0057] E pp =E max -E min =2U dc (3)

[0058] From formula (3), it can be seen that when the motor excitation winding is powered by the H-bridge full bridge, the peak-to-peak value of the induced pulsating voltage E of the excitation winding is pp Only with the excitation winding DC bus voltage U dc It is related to the H-bridge PI controller parameters and has nothing to do with them.

[0059] The modulation wave of the H bridge is calculated using the peak-to-peak value of the induced pulsating voltage of the excitation winding and the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the PI controller;

[0060] The modulation wave of the H-bridge is superimposed with multiple harmonics as a DC component to obtain the H-bridge output voltage, and then the excitation winding resistance voltage drop is subtracted from the H-bridge output voltage to obtain the excitation winding induced pulsating voltage. The excitation winding induced pulsating voltage is related to the PI parameters, thereby achieving the effect of the PI parameters on the excitation winding induced pulsating voltage.

[0061] It should be further explained that the 12-slot 10-pole electric excitation field modulation motor topology used in this example is as follows Figure 4 The main parameters of the motor are listed in Table 1, and the size parameter diagram is shown in Figure 5 shown.

[0062] Table 1 Main parameters of 12-slot 10-pole electric excitation field modulation motor

[0063] parameter unit value <![CDATA[Inner diameter of stator, R si > mm 58.94 <![CDATA[Stator yoke diameter, R sy > mm 99.86 <![CDATA[Stator outer diameter, R so > mm 105 <![CDATA[Inner diameter of rotor, R ri > mm 20 <![CDATA[Rotor yoke diameter, R ry > mm 40 <![CDATA[Outer diameter of rotor, R ro > mm 58.44 Unilateral air gap width, g mm 0.5 <![CDATA[Axial length of the motor, l s > mm 125 <![CDATA[Rotor pole radian, θ rp > ° 11.9 <![CDATA[Stator tooth radian, θ st > ° 7.5 <![CDATA[Number of rotor poles, N r > - 10 <![CDATA[Number of stator slots, N s > - 12 Coil turns, N - 24 Number of parallel branches, b - 1 Silicon steel sheet type - DR510–50

[0064] The 12-slot 10-pole electric excitation field modulation motor used in this example has its field winding powered by an H-bridge full bridge, with a DC bus voltage of 40Vdc for the field winding, and its armature winding powered by a three-phase voltage-type full-bridge inverter, with a DC bus voltage of 200Vdc for the armature winding. The switching frequencies of the field winding and the armature winding are both 10kHz. The motor control mode is zero d-axis current control, and the q-axis current i q =12A, excitation current i f =24.59Adc, the speed is set to 600 rpm. The drive system of the motor is as follows Figure 6 shown.

[0065] When the motor excitation winding is powered by the H-bridge full bridge, Figure 7 It can be seen that the modulation wave M of the H bridge f It can be expressed as:

[0066]

[0067] Among them, i dcref with i dc They are the reference value and instantaneous value of the excitation winding current respectively. p With K i They are the proportional coefficient and integral coefficient of the H-bridge PI controller respectively.dc =E pp is the peak-to-peak value of the induced pulsating voltage of the excitation winding.

[0068] It can be seen from formula (4) that when the motor excitation winding is powered by an H-bridge full bridge, the proportional coefficient and integral coefficient of the H-bridge PI controller will affect the harmonic amplitude in the H-bridge modulation wave.

[0069] The H-bridge modulation wave determines the harmonics in the output voltage of the H-bridge, and also determines the harmonics in the induced pulsating voltage of the motor excitation winding. In this example, the motor is a 12-slot 10-pole electric excitation magnetic field modulation motor, so the main harmonic order of its excitation winding current is 6th, and the main harmonic order of its H-bridge modulation wave is also 6th. Assuming that the H-bridge modulation wave is a DC component superimposed with a 6th harmonic, its expression is shown in the following formula:

[0070] M f (t) = M0 + M6 cos(6ω e t+θ1) (5)

[0071] Among them, M0 and M6 are the amplitudes of the DC component and the 6th harmonic component in the modulation wave respectively. e is the angular frequency of the motor. θ1 is the phase of the 6th harmonic of the modulation wave.

[0072] When the motor modulation wave expression is as shown in formula (5) and the carrier frequency is f PWM When the triangular carrier is used, the output voltage F of the H bridge can be converted into mk Decomposed into a series of Fourier series, its expression is shown in formula (6):

[0073]

[0074] Among them, m=1,2,3…,6k=0,±6,±12…are the harmonic orders of the carrier wave and the modulating wave respectively. PWM With f e are PWM frequency and motor base frequency respectively. n (M6mπ) represents the nth-order Bessel function.

[0075] From formula (6), we can get the amplitude F6 of the sixth harmonic in the H-bridge output voltage:

[0076] F6(t)=2M6U dc sin[2π×6f e t+nθ1] (7)

[0077] From formula (7), it can be seen that the amplitude of the 6th harmonic in the H-bridge output voltage is positively correlated with the 6th harmonic in the modulation wave. Therefore, the amplitude of the 6th harmonic in the H-bridge modulation wave is positively correlated with the 6th harmonic amplitude of the H-bridge output voltage, and is also positively correlated with the 6th harmonic amplitude of the induced pulsating voltage of the motor excitation winding.

[0078] From formula (4), we can see that the proportional coefficient K of the H-bridge PI controller is p It will affect the amplitude of the 6th harmonic in the H-bridge modulation wave. The smaller K p It will reduce the amplitude of the sixth harmonic in the H-bridge modulation wave, thereby reducing the amplitude of the sixth harmonic in the induced pulsating voltage of the excitation winding. Since the sixth harmonic of the H-bridge modulation wave is integrated to 0 in one electrical cycle, the integral coefficient K of the H-bridge PI controller i It has little effect on the amplitude of the sixth harmonic in the H-bridge modulation wave, so its effect on the amplitude of the sixth harmonic in the induced pulsating voltage of the excitation winding is also extremely small.

[0079] This example uses magnetic field-circuit joint simulation to verify the correctness of the conclusion. The default proportional coefficient K of the H-bridge PI controller is p is 14, the integral coefficient K i is 500, by traversing K p With K i To verify its influence on the peak-to-peak value of the induced pulsating voltage of the motor excitation winding, the sixth harmonic of the H-bridge modulation wave and the sixth harmonic of the induced pulsating voltage of the motor excitation winding, the results are as follows Figure 8 , Fig. 9 , Fig.10 and Fig.11 shown.

[0080] Depend on Figure 8 and Fig.10 It can be seen that K p With K i It has no effect on the peak-to-peak value of the induced pulsating voltage of the motor's excitation winding, which is consistent with the theoretical analysis results.

[0081] Depend on Fig. 9 It can be seen that the 6th harmonic of the H-bridge modulation wave, the 6th harmonic of the induced pulsating voltage of the motor excitation winding and K p Positively correlated. Fig.11 It can be seen that K i The sixth harmonic of the H-bridge modulation wave and the sixth harmonic of the induced pulsating voltage of the motor excitation winding are minimally affected. The simulation results are consistent with the theoretical analysis results.

[0082] The analysis method of the influence of PI parameters on the induced pulsating voltage of the excitation winding proposed in the present invention gives the influence mechanism of PI parameters of the H-bridge PI controller on the induced pulsating voltage of the excitation winding under PWM excitation, which has a guiding role in suppressing the induced pulsating voltage of the excitation winding under PWM excitation.

[0083] On the other hand, Figure 2 As shown, the embodiment of the present invention further discloses a PI parameter impact analysis system, including:

[0084] Receiving voltage module: used to receive the maximum and minimum values ​​of the H-bridge output voltage when the excitation winding of the motor is excited by the H-bridge full bridge;

[0085] Difference module: used to make a difference between the maximum value of the H-bridge output voltage and the minimum value of the H-bridge output voltage to obtain the peak-to-peak value of the induced pulsating voltage of the excitation winding, and the peak-to-peak value of the induced pulsating voltage of the excitation winding is independent of the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the PI controller of the excitation winding;

[0086] Calculation module: used to calculate the modulation wave of the H bridge using the peak-to-peak value of the induced pulsating voltage of the excitation winding and the PI parameters;

[0087] Output voltage module: used to convert the modulation wave of the H-bridge into a DC component and superimpose multiple harmonics to obtain the H-bridge output voltage, and then subtract the excitation winding resistance voltage drop from the H-bridge output voltage to obtain the excitation winding induced pulsating voltage. The excitation winding induced pulsating voltage is related to the PI parameters, thereby achieving the effect of the PI parameters on the excitation winding induced pulsating voltage.

[0088] Based on the same inventive concept, the present invention also provides a computer device, which includes: one or more processors, and a memory for storing one or more computer programs; the program includes program instructions, and the processor is used to execute the program instructions stored in the memory. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is used to implement one or more instructions, specifically for loading and executing one or more instructions in a computer storage medium to implement the above method.

[0089] It needs to be further explained that, based on the same inventive concept, the present invention also provides a computer storage medium, on which a computer program is stored, and the computer program is executed by a processor to execute the above method. The storage medium can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electrical, magnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0090] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0091] The above shows and describes the basic principles, main features and advantages of the present disclosure. Those skilled in the art should understand that the present disclosure is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure may have various changes and improvements, and these changes and improvements fall within the scope of the present disclosure to be protected.

Claims

1. A PI parameter impact analysis method, characterized in that: The method comprises the following steps: The maximum and minimum values ​​of the H-bridge output voltage when the field winding of the receiving motor is excited by the H-bridge full bridge; The maximum value of the H-bridge output voltage is subtracted from the minimum value of the H-bridge output voltage to obtain the peak-to-peak value of the induced pulsating voltage of the excitation winding, and the peak-to-peak value of the induced pulsating voltage of the excitation winding is independent of the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the PI controller of the excitation winding; The modulation wave of the H bridge is calculated using the peak-to-peak value of the induced pulsating voltage of the excitation winding and the PI parameters; The modulation wave of the H-bridge is set to be a DC component superimposed with multiple harmonics to obtain the H-bridge output voltage, and then the excitation winding resistance voltage drop is subtracted from the H-bridge output voltage to obtain the excitation winding induced pulsating voltage. The excitation winding induced pulsating voltage is related to the PI parameters, thereby achieving the effect of the PI parameters on the excitation winding induced pulsating voltage.

2. A PI parameter impact analysis method according to claim 1, characterized in that: The maximum value and the minimum value of the H-bridge output voltage are calculated according to Kirchhoff's voltage law.

3. A PI parameter impact analysis method according to claim 1, characterized in that: The maximum value of the H-bridge output voltage E max The expression is: E max =U dc -v load -v F Among them, U dc is the DC bus voltage of the excitation winding, v load is the load voltage drop, v F is the conduction voltage drop of the power device; The minimum value of the H-bridge output voltage E min The expression is: E min =-U dc -v load -v F 。 4. A PI parameter impact analysis method according to claim 3, characterized in that: The peak-to-peak value of the induced pulsating voltage E of the excitation winding pp =E max -E min =2U dc .

5. A PI parameter impact analysis method according to claim 4, characterized in that: The peak-to-peak value of the induced pulsating voltage E of the excitation winding pp and the excitation winding DC bus voltage U dc It is related to PI parameters.

6. A PI parameter impact analysis method according to claim 1, characterized in that: The calculation process of the modulation wave of the H bridge is as follows: Among them, M f is the modulation wave of the H bridge, i dcref with i dc are the reference value and instantaneous value of the excitation winding current respectively; K p With K i are the proportional coefficient and integral coefficient of the H-bridge PI controller, 2U dc =E pp It is the peak-to-peak value of the induced pulsating voltage of the excitation winding.

7. A PI parameter impact analysis method according to claim 6, characterized in that: The modulation wave of the H bridge is a DC component superimposed LCM (N) by double Fourier integration. s , N r ) / N r The Fourier pole expansion of the H-bridge output voltage is obtained when the subharmonic is obtained, where LCM is the lowest common multiple. The LCM (N s , N r ) / N r The subharmonic amplitude will affect the LCM (N) in the H-bridge output voltage. s , N r ) / N r The subharmonic amplitude affects the LCM (N) of the induced pulsating voltage of the excitation winding. s , N r ) / N r Subharmonic amplitude, N s is the number of stator slots, N r is the number of rotor stages.

8. A PI parameter impact analysis method according to claim 7, characterized in that: The LCM (N s , N r ) / N r The first is the main harmonic order of the modulation wave of the H bridge.

9. A PI parameter impact analysis method according to claim 7, characterized in that: The H-bridge output voltage F mk The expression is as follows: Where m = 1, 2, 3, ..., N pe , k=0, ±6, ±12…are the harmonic orders of the carrier wave and the modulating wave respectively, N pe =LCM(N s , N r ) / N r is the frequency of the field winding current, f PWM With f e are PWM frequency and motor base frequency, M0 and M pe are the DC component and N in the modulation wave respectively. pe The amplitude of the subharmonic component, θ1 is the phase of the modulated wave, J k (M pe mπ) represents the k-order Bessel function, U dc is the DC bus voltage of the excitation winding; From the above formula, the H-bridge output voltage F mk Medium pe The amplitude of the subharmonic is modulated by the H-bridge modulation wave M f Medium pe The amplitude of the subharmonic component M pe Therefore, the H-bridge output voltage F mk It is also affected by the PI parameters, and the H-bridge output voltage F mk Subtracting the resistance voltage drop of the excitation winding will give the induced pulsating voltage of the excitation winding, so the final induced pulsating voltage of the excitation winding is also affected by the PI parameters.

10. A PI parameter impact analysis system, characterized in that: include: Receiving voltage module: used to receive the maximum and minimum values ​​of the H-bridge output voltage when the excitation winding of the motor is excited by the H-bridge full bridge; Difference module: used to make a difference between the maximum value of the H-bridge output voltage and the minimum value of the H-bridge output voltage to obtain the peak-to-peak value of the induced pulsating voltage of the excitation winding, and the peak-to-peak value of the induced pulsating voltage of the excitation winding is independent of the PI parameters, wherein the PI parameters are the proportional coefficient and the integral coefficient of the PI controller of the excitation winding; Calculation module: used to calculate the modulation wave of the H bridge using the peak-to-peak value of the induced pulsating voltage of the excitation winding and the PI parameters; Output voltage module: used to set the modulation wave of the H-bridge to a DC component superimposed with multiple harmonics to obtain the H-bridge output voltage, and then subtract the excitation winding resistance voltage drop from the H-bridge output voltage to obtain the excitation winding induced pulsating voltage. The excitation winding induced pulsating voltage is related to the PI parameters, thereby achieving the effect of the PI parameters on the excitation winding induced pulsating voltage.

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