Permanent magnet synchronous motor fundamental wave voltage obtaining method suitable for high modulation degree

Abstract

The invention discloses a permanent magnet synchronous motor fundamental wave voltage obtaining method suitable for a high modulation degree. Under a dq-axis synchronous rotating coordinate system, through establishing a mapping relation between a modulation degree and a switch tube reference conduction time, an actual conduction time of a switch tube after being influenced by a dead time and a switch tube on-off delay is analyzed, and an inverter nonlinear voltage error model suitable for a high modulation degree is established. And after the output voltage calculated by the controller is subtracted from the nonlinear voltage error of the inverter, controller output delay and inverter output delay compensation is performed on the obtained voltage, and then the compensated voltage passes through a low-pass filter, so that the fundamental voltage can be obtained. The method does not need an additional hardware circuit, is simple to implement, can accurately obtain the fundamental wave voltage of the permanent magnet synchronous motor under the high modulation degree, and is suitable for any control algorithm taking the fundamental wave voltage of the permanent magnet synchronous motor as an input quantity.

Description

Technical Field

[0001] The present invention relates to a method for obtaining a fundamental voltage of a permanent magnet synchronous motor, and in particular to a method for obtaining a fundamental voltage of a permanent magnet synchronous motor suitable for a high modulation system. Background Art

[0002] Permanent magnet synchronous motor (PMSM) has the advantages of compact structure and high power density, and is widely used in electric vehicle drive systems and servo control systems. In recent years, with the rapid development of motor control technology, many high-performance control algorithms use the fundamental voltage of PMSM as one of the key input quantities, aiming to further improve the control accuracy and robustness of the system. This trend highlights the importance of PMSM fundamental voltage, and its accuracy directly affects the overall performance of the control algorithm and the quality assurance of motor operation. Therefore, achieving accurate acquisition of PMSM fundamental voltage is not only an inevitable requirement for technological progress, but also the key to ensuring the stable operation of the motor system and optimizing performance.

[0003] Current methods usually perform inverter nonlinear voltage error (INVE) compensation on the controller output voltage, and then use the compensated voltage as the PMSM fundamental voltage in the control algorithm. Therefore, accurate calculation of INVE is the key to accurately obtain the PMSM fundamental voltage.

[0004] INVE is mainly caused by dead time, switch on / off delay, and switch and diode conduction voltage drop. When building the current INVE model, the voltage error caused by dead time and switch on / off delay is usually considered to be a fixed value. Under high modulation, the influence of dead time and switch on / off delay becomes complex and diverse and cannot be ignored. The voltage error generated changes with the modulation, resulting in a decrease in the accuracy of the PMSM fundamental voltage obtained by traditional INVE under high modulation. In addition, high modulation means high voltage vector amplitude, which means high speed and high load. Under this condition, the controller output delay and inverter output delay are also important reasons for the error between the controller output voltage and the PMSM fundamental voltage. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for obtaining the fundamental voltage of a permanent magnet synchronous motor under a high modulation system, which can accurately obtain the fundamental voltage of the permanent magnet synchronous motor under a high modulation system, in order to overcome the shortcomings of the prior art.

[0006] The technical solution adopted by the present invention is: a method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation system, comprising the following steps:

[0007] (1) Real-time monitoring of the motor ABC three-phase current i a、i b and i c , DC bus voltage U dc 、Motor rotor position angle θ m And the motor speed n is sampled;

[0008] (2) Based on the space vector pulse width modulation algorithm, the switching time T of each phase bridge arm in the current switching cycle is obtained a 、T b and T c , the switching time T of each phase bridge arm in the previous switching cycle a0 、T b0 and T c0 , and the action time of the effective vector corresponding to the reference voltage vector of the current switching cycle, on this basis, the output voltage u of the d-axis and q-axis of the current control cycle is calculated dsvout and u qsvout ;

[0009] (3) Calculate the reference on-time of the switch tube in the current switching cycle and the previous switching cycle, and establish a nonlinear voltage error model of the inverter;

[0010] (4) Calculate the inverter nonlinear voltage error u of the d-axis and q-axis of the current switching cycle according to the established inverter nonlinear voltage error model dinve and u qinve , and then correspond to the output voltage u of the d-axis and q-axis of the current control cycle respectively dsvout and u qsvout Make a difference and get the d and q axis voltage u after the inverter nonlinear voltage compensation dmpre and u qmpre ;

[0011] (5) The d-axis and q-axis voltages u after inverter nonlinear voltage compensation dmpre and u qmpre Perform controller output delay compensation and inverter output delay compensation to obtain the d and q axis voltage u after delay compensation dmrev and u qmrev ;

[0012] (6) The d-axis and q-axis voltages u after the controller output delay compensation and the inverter output delay compensation are calculated. dmrev and u qmrev Perform low-pass filtering to obtain the fundamental voltage of the permanent magnet synchronous motor.

[0013] The present invention provides a method for obtaining the fundamental voltage of a permanent magnet synchronous motor under a high modulation system. By exploring the mathematical relationship between the modulation system and the reference conduction time of the switch tube, and exploring the actual conduction time of the switch tube after the dead time and the switch tube on-off delay, an INVE model suitable for a high modulation system is established; and on this basis, considering the influence of the controller output delay and the inverter output delay on the fundamental voltage transmission, a method for calculating the fundamental voltage of a PMSM suitable for a high modulation system is proposed. The present invention does not require additional hardware circuits, is simple to implement, can accurately obtain the fundamental voltage of a permanent magnet synchronous motor under a high modulation system, and is suitable for any control algorithm that takes the fundamental voltage of a permanent magnet synchronous motor as an input quantity. The method of the present invention provides an accurate PMSM fundamental voltage value for a control algorithm that takes the PMSM fundamental voltage as an input quantity, which is of great significance for improving the high-quality operation of the PMSM system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a block diagram of a method for obtaining fundamental voltage of a permanent magnet synchronous motor under high modulation system of the present invention;

[0015] Figure 2 This is a schematic diagram of a method for obtaining the fundamental voltage of a permanent magnet synchronous motor under a high modulation system according to the present invention;

[0016] Figure 3a is the modulation index MI and the reference conduction time T of the upper bridge arm of phase z zHref Relationship diagram;

[0017] Figure 3b is the modulation index MI and the reference conduction time T of the lower bridge arm of phase z zLref Relationship diagram;

[0018] Figure 4 is the reference conduction time T of the upper bridge arm of phase z at different reference conduction times (the reference conduction time T of the current switching cycle and the previous switching cycle) zHref and T zHref0 ) Reference switch signal PWM in the value range zHref and the actual conduction state S zH Schematic diagram of

[0019] Figure 5 is the reference conduction time T of the lower bridge arm of phase z at different reference conduction times (the reference conduction time T of the current switching cycle and the previous switching cycle) zLref and T zLref0 ) Reference switch signal PWM in the value range zLref and the actual conduction state S zL Schematic diagram of

[0020] Figure 6aIt is a torque waveform diagram when obtaining the fundamental voltage of the permanent magnet synchronous motor without performing inverter nonlinear voltage error compensation, adopting a traditional inverter nonlinear voltage error model, and adopting the inverter nonlinear voltage error model of the present invention;

[0021] Figure 6b The torque error diagram is obtained when the fundamental voltage of the permanent magnet synchronous motor is obtained without performing inverter nonlinear voltage error compensation, adopting the traditional inverter nonlinear voltage error model, and adopting the inverter nonlinear voltage error model proposed by the present invention.

[0022] Figure 7a It is a torque waveform diagram when the fundamental voltage of the permanent magnet synchronous motor is obtained with and without considering the controller output delay and inverter output delay compensation;

[0023] Figure 7b It is a torque error diagram when the fundamental voltage of the permanent magnet synchronous motor is obtained with and without considering the controller output delay and the inverter output delay compensation. DETAILED DESCRIPTION

[0024] The following is a detailed description of a method for obtaining the fundamental voltage of a permanent magnet synchronous motor under a high modulation system according to the present invention in conjunction with the embodiments and the accompanying drawings.

[0025] like Figure 1 , Figure 2 As shown, a method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation index of the present invention comprises the following steps:

[0026] (1) Real-time monitoring of the motor ABC three-phase current i a 、i b and i c , DC bus voltage U dc 、Motor rotor position angle θ m And the motor speed n is sampled;

[0027] (2) Based on the space vector pulse width modulation (SVPWM) algorithm, the switching time T of each phase bridge arm in the current switching cycle is obtained a 、T b and T c , the switching time T of each phase bridge arm in the previous switching cycle a0 、T b0 and T c0 , and the action time of the effective vector corresponding to the reference voltage vector of the current switching cycle, on this basis, the output voltage u of the d-axis and q-axis of the current control cycle is calculated dsvout and u qsvout ;

[0028] The calculation of the output voltage u of the d-axis and q-axis in the current control cycle dsvout and uqsvout The mathematical formula is:

[0029]

[0030] in,

[0031]

[0032] Where MI is the modulation index, U ref is the reference voltage vector fundamental amplitude of space vector pulse width modulation (SVPWM), U svout is the controller output voltage amplitude, θ svout is the angle between the controller output voltage vector and the a-axis, θ ref is the angle between the reference voltage vector and the a-axis, T x 、T y are the action time of adjacent effective vectors in the sector where the voltage vector is located, where T y The corresponding effective vector is ahead of T x The corresponding effective vector, T s is the switching cycle, which is the same as the control cycle, U dc is the DC bus voltage.

[0033] (3) Calculate the reference on-time of the switch tube in the current switching cycle and the previous switching cycle, and establish the inverter nonlinear voltage error (INVE) model;

[0034] The mathematical formula for calculating the reference on-time of the switch tube in the current switching cycle and the previous switching cycle is:

[0035]

[0036] In the formula, z represents phase A, B or C, T zHref 、T zLref are the reference on-time of the upper and lower bridge arm switches of phase z in the current switching cycle, T zHref0 、T zLref0 They are respectively the reference on-time of the upper and lower bridge arm switches of phase z in the previous switching cycle.

[0037] When modeling the traditional inverter nonlinear voltage error model, it is usually assumed that after the dead time and the switch on / off delay, the difference between the reference on time and the actual on time of the switch in the current switching cycle is a constant value T ed , the traditional inverter nonlinear voltage error model is:

[0038]

[0039] In the formula, z represents phase A, B or C, D z (kT s) is the inverter nonlinear voltage error of phase z in the current switching cycle, i z is the z-phase current, T zHref 、T zLref are the reference conduction time of the upper and lower bridge arm switches in the current switching cycle, T zH 、T zL are the actual conduction time of the upper and lower bridge arm switches in the current switching cycle, U dc is the DC bus voltage, U sat is the saturation voltage of the switch tube, U d is the diode conduction voltage drop, the time deviation caused by the dead time and the turn-on and turn-off delay T ed =T d +T on -T off , T d is the dead time, T on T is the switch-on delay, off is the switch off delay, T s is the switching period, which is the same as the control period.

[0040] After the dead time and the switch on / off delay, the difference between the reference on time and the actual on time of the switch in the current switching cycle is a constant value T ed The premise is that the switch tube completes the switching action in the current switching cycle and the upper bridge arm reference conduction time is greater than T ed , the lower bridge arm reference conduction time is greater than 2 (T d +T on ), and the influence of the previous switching cycle is not considered. However, this premise does not hold when MI is large. The specific analysis is as follows:

[0041] Modulation index (MI) and reference conduction time (T zHref 、T zLref ) are shown in the following diagrams: Figure 3a , 3b As shown, it can be seen that the larger the MI, the higher the T zHref and T zLref The closer to the minimum value 0 or the maximum value T s The specific mathematical relationship is as follows:

[0042]

[0043] In the formula, q is the current sector of the voltage vector, θ svout is the angle between the controller output voltage vector and the a-axis.

[0044] T zHref0 and T zLref0 It is the reference conduction time of the switch tube of the upper and lower bridge arms of phase z in the previous switching cycle.z and T z0 They are the switching time of the z-phase bridge arm in the current switching cycle and the previous switching cycle respectively. Figure 4 For T zHref and T zHref0 Under different value ranges, the reference switching signal PWM of the upper bridge arm of phase z zHref and the actual conduction state S zH Schematic diagram of T s k is the current switching cycle, T s k-1 is the last switching cycle. High level 1 means on, low level 0 means off. Figure 4 middle:

[0045] (a) is T d +T on <T zHref <T s -2T off ,0≤T zHref0 <T s -2T off , at this time, T zHref >T ed , the upper bridge arm of phase z in the current switching cycle completes the switching action and is not affected by the previous switching cycle, T zHref -T zH =T ed .

[0046] (b) is 0≤T Href ≤T d +T on ,0≤T Href0 <T s -2T off , at this time, it is not affected by the previous switching cycle, but T zHref <T ed , the upper bridge arm of phase z does not switch during the current switching cycle, T zHref -T zH =T zHref .

[0047] (c) is T s -2T off ≤T Href ≤T s ,0≤T Href0 <T s -2T off , at this time, T zHref >T ed , and is not affected by the previous switching cycle, but the shutdown action of the upper bridge arm of phase z in the current switching cycle has not been completed, T zHref -T zH =Td +T on -T z .

[0048] (d) is T d +T on <T Href <T s -2T off ,T s -2T off ≤T Href0 ≤T s , at this time, T zHref >T ed , the upper bridge arm of phase z completes the switching action in the current switching cycle, but the closing action of the previous switching cycle is not completed, T zHref -T zH =T ed -T off +T z0 .

[0049] (e) is 0≤T Href ≤T d +T on ,T s -2T off ≤T Href0 ≤T s , at this time, T zHref <T ed , the upper bridge arm of phase z does not switch in the current switching cycle, and the shutdown action of the previous switching cycle is not completed, T zHref -T zH =T zHref -T off +T z0 .

[0050] (f) is T s -2T off ≤T Href ≤T s ,T s -2T off ≤T Href0 ≤T s ,T Href ∩T Href0 ≠T s , at this time, T zHref >T ed , but the shutdown action of the upper bridge arm of phase z in the current switching cycle and the previous switching cycle has not been completed, T zHref -T zH =T zHref -T z +T z0 .

[0051] (g) is THref =T Href0 =T s , at this time, T zHref >T ed , is not affected by the previous switching cycle, but the upper bridge arm of phase z in the current switching cycle does not switch, T zHref -T zH =0.

[0052] Figure 5 It is in T zLref and T zLref0 Under different value ranges, the reference switching signal PWM of the lower bridge arm of phase z zLref and the actual conduction state S zL Schematic diagram of . Figure 5 middle:

[0053] (a) is 2(T d +T on )<T zLref <T s ,2(T d +T on ) <T zLref0 ≤T s , at this time, T zLref >2(T d +T on ), the lower bridge arm of phase z in the current switching cycle completes the switching action and is not affected by the previous switching cycle, T zLref -T zL =T ed .

[0054] (b) is T zLref =T zLref0 =T s , at this time, T zLref >2(T d +T on ), which is not affected by the previous switching cycle, but the lower bridge arm of phase z in the current switching cycle does not act, T zLref -T zL =0.

[0055] (c) is 0≤T zLref ≤2(T d +T on ),2(T d +T on )<T zLref0 ≤T s , at this time, it is not affected by the previous switching cycle, but T zLref <2(T d +T on ), and the opening action of the lower bridge arm of phase z in the current switching cycle has not been completed, T zLref-T zL =T z -T off .

[0056] (d) is 2(T d +T on )<T zLref <T s ,0≤T zLref0 ≤2(T d +T on ), at this time, T zLref >2(T d +T on ), the lower bridge arm of phase z in the current switching cycle completes the switching action, but the opening action of the tube in the previous switching cycle is not completed, T zLref -T zL =2T ed +T off -T z0 .

[0057] (e) is T zLref =T s ,0≤T zLref0 ≤2(T d +T on ), at this time, T zLref >2(T d +T on ), but affected by the previous switching cycle, the lower bridge arm of phase z in the current switching cycle does not shut down the tube, T zLref -T zL =T ed +T off -T z0 .

[0058] (f) is 0≤T zLref ≤2(T d +T on ),0≤T zLref0 ≤2(T d +T on ),T zLref +T zLref0 >2(T d +T on ), at this time, the lower bridge arm of phase z of the current switching cycle completes the switching action, but T zLref <2(T d +T on ), and the opening action of the previous switching cycle has not been completed, affecting the previous switching cycle, T zLref -T zL =T ed +T z -T z0 .

[0059] (g) is T zLref +T zLref0 ≤2(T d +T on ), at this time, T zHref <T ed , and the opening action of the lower bridge arm of phase z in the current switching cycle and the previous switching cycle has not been completed, and no switching action occurs in the current switching cycle, T zLref -T zL =T zLref .

[0060] Combination Figure 4 , Figure 5 and formula (7), the inverter nonlinear voltage error (INVE) model described in the present invention is:

[0061]

[0062] The calculation coefficients in the formula are:

[0063]

[0064]

[0065]

[0066] Where D z (kT s ) is the inverter nonlinear voltage error of phase z in the current switching cycle, i z is the z-phase current, T d is the dead time, T on T is the switch-on delay, off T is the time deviation caused by the switch tube turn-off delay, dead time and turn-on and turn-off delay ed =T d +T on -T off , T s is the switching cycle, which is the same as the control cycle, U sat is the saturation voltage of the switch tube, U d is the diode conduction voltage drop, U dc is the DC bus voltage, T z and T z0 are the switching time of the z-phase bridge arm in the current switching cycle and the previous switching cycle, respectively, T zHref 、T zLref are the reference on-time of the upper and lower bridge arm switches of phase z in the current switching cycle, T zHref0 、T zLref0 They are respectively the reference on-time of the upper and lower bridge arm switches of phase z in the previous switching cycle.

[0067] (4) Calculate the inverter nonlinear voltage error (INVE) u of the d-axis and q-axis of the current switching cycle based on the established inverter nonlinear voltage error (INVE) model dinve and u qinve , and then correspond to the output voltage u of the d-axis and q-axis of the current control cycle respectively dsvout and u qsvout Make a difference and get the d and q axis voltage u after the inverter nonlinear voltage compensation dmpre and u qmpre ;include:

[0068] After ABC-dq coordinate transformation, the nonlinear voltage error of the inverter in the dq two-phase synchronous rotating coordinate system is obtained. The mathematical formula is as follows:

[0069]

[0070] In the formula, θ e is the motor electrical angle;

[0071] The inverter nonlinear voltage error (INVE) u of the d-axis and q-axis of the current switching cycle is dinve and u qinve The output voltages u corresponding to the d-axis and q-axis of the current control cycle are dsvout and u qsvout Do the difference and get:

[0072]

[0073] In the formula, u dmpre 、u qmpre They are the d-axis and q-axis voltages after inverter nonlinear voltage compensation.

[0074] (5) The d-axis and q-axis voltages u after inverter nonlinear voltage compensation dmpre and u qmpre Perform controller output delay compensation and inverter output delay compensation to obtain the d and q axis voltage u after delay compensation dmrev and u qmrev ;

[0075] The mathematical formulas of the d-axis and q-axis voltages after the controller output delay compensation and the inverter output delay compensation are:

[0076]

[0077] In the formula, ω e is the motor electrical angle, u dmrev and u qmrev They are the d-axis and q-axis voltages after controller output delay compensation and inverter output delay compensation, respectively.

[0078] (6) The d-axis and q-axis voltages u after the controller output delay compensation and the inverter output delay compensation are calculated. dmrev and u qmrev Perform low-pass filtering to obtain the fundamental voltage of the permanent magnet synchronous motor (PMSM).

[0079] like Figure 6a , Figure 6b The figure shows the comparison experiment when obtaining the PMSM fundamental voltage without INVE compensation, using the traditional INVE model and using the INVE model proposed by the present invention; it can be seen that when MI=0.72 and 0.867, both the traditional IVNE model and the INVE model of the present invention can obtain relatively accurate PMSM fundamental voltage, but as MI increases, the acquisition accuracy of the traditional IVNE model decreases significantly, while the INVE model of the present invention can still maintain a high acquisition accuracy. This proves the effectiveness of the IVNE model proposed by the present invention.

[0080] like Figure 7a , Figure 7b The figure shows the comparison of the experimental diagram when the PMSM fundamental voltage is obtained with and without considering the controller output delay and inverter output delay compensation. It can be seen that with the increase of torque and speed, the PMSM fundamental voltage acquisition accuracy is significantly reduced when delay compensation is not considered, while considering delay compensation can maintain a high acquisition accuracy. This proves the effectiveness of controller output delay and inverter output delay compensation.

[0081] The above experimental results verify the effectiveness and superiority of the method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation system of the present invention.

Claims

1. A method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation, characterized in that: The steps include: (1) Real-time monitoring of the motor ABC three-phase current i a 、i b and i c , DC bus voltage U dc 、Motor rotor position angle θ m And the motor speed n is sampled; (2) Based on the space vector pulse width modulation algorithm, the switching time T of each phase bridge arm in the current switching cycle is obtained a , T b and T c , the switching time T of each phase bridge arm in the previous switching cycle a0 , T b0 and T c0 , and the action time of the effective vector corresponding to the reference voltage vector of the current switching cycle, on this basis, the output voltage u of the d-axis and q-axis of the current control cycle is calculated dsvout and u qsvout ; (3) Calculate the reference on-time of the switch tube in the current switching cycle and the previous switching cycle, and establish a nonlinear voltage error model of the inverter; (4) Calculate the inverter nonlinear voltage error u of the d-axis and q-axis of the current switching cycle according to the established inverter nonlinear voltage error model dinve and u qinve , and then correspond to the output voltage u of the d-axis and q-axis of the current control cycle respectively dsvout and u qsvout Make a difference and get the d and q axis voltage u after the inverter nonlinear voltage compensation dmpre and u qmpre ; (5) The d-axis and q-axis voltages u after inverter nonlinear voltage compensation dmpre and u qmpre Perform controller output delay compensation and inverter output delay compensation to obtain the d and q axis voltage u after delay compensation dmrev and u qmrev ; (6) The d-axis and q-axis voltages u after the controller output delay compensation and the inverter output delay compensation are calculated. dmrev and u qmrev Perform low-pass filtering to obtain the fundamental voltage of the permanent magnet synchronous motor.

2. The method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation index according to claim 1, characterized in that: The output voltage u of the d-axis and q-axis of the current control cycle is calculated in step (2) dsvout and u qsvout The mathematical formula is: in, Where MI is the modulation index, U ref is the reference voltage vector fundamental amplitude of space vector pulse width modulation, U svout is the controller output voltage amplitude, θ svout is the angle between the controller output voltage vector and the a-axis, θ ref is the angle between the reference voltage vector and the a-axis, T x , T y are the action time of adjacent effective vectors in the sector where the voltage vector is located, where T y The corresponding effective vector is ahead of T x The corresponding effective vector, T s is the switching cycle, which is the same as the control cycle, U dc is the DC bus voltage.

3. The method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation index according to claim 1, characterized in that: The mathematical formula for calculating the reference on-time of the switch tube in the current switching cycle and the previous switching cycle described in step (3) is: In the formula, z represents phase A, B or C, T zHref , T zLref are the reference on-time of the upper and lower bridge arm switches of phase z in the current switching cycle, T zHref0 , T zLref0 They are respectively the reference on-time of the upper and lower bridge arm switches of phase z in the previous switching cycle.

4. The method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation index according to claim 1 is characterized in that: The inverter nonlinear voltage error model described in step (3) is: The calculation coefficients in the formula are: Where D z (kT s ) is the inverter nonlinear voltage error of phase z in the current switching cycle, i z is the z-phase current, T d is the dead time, T on T is the switch-on delay, off T is the time deviation caused by the switch tube turn-off delay, dead time and turn-on and turn-off delay ed =T d +T on -T off , T s is the switching cycle, which is the same as the control cycle, U sat is the saturation voltage of the switch tube, U d is the diode conduction voltage drop, U dc is the DC bus voltage, T z and T z0 are the switching time of the z-phase bridge arm in the current switching cycle and the previous switching cycle, respectively, T zHref , T zLref are the reference on-time of the upper and lower bridge arm switches of phase z in the current switching cycle, T zHref0 , T zLref0 They are respectively the reference on-time of the upper and lower bridge arm switches of phase z in the previous switching cycle.

5. The method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation index according to claim 1, characterized in that: Step (4) comprises: After ABC-dq coordinate transformation, the nonlinear voltage error of the inverter in the dq two-phase synchronous rotating coordinate system is obtained. The mathematical formula is as follows: In the formula, θ e is the motor electrical angle; The inverter nonlinear voltage error u of the d-axis and q-axis of the current switching cycle is dinve and u qinve The output voltages u corresponding to the d-axis and q-axis of the current control cycle are dsvout and u qsvout Do the difference and get: In the formula, u dmpre 、u qmpre They are the d-axis and q-axis voltages after inverter nonlinear voltage compensation.

6. The method for obtaining the fundamental voltage of a permanent magnet synchronous motor under high modulation index according to claim 1, characterized in that: The mathematical formulas of the d-axis and q-axis voltages after the controller output delay compensation and the inverter output delay compensation described in step (5) are: In the formula, ω e is the motor electrical angle, u dmrev and u qmrev They are the d-axis and q-axis voltages after controller output delay compensation and inverter output delay compensation, respectively.

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