Robust digital decoupling control method for high-speed permanent magnet synchronous motor under low carrier frequency ratio

Abstract

The invention discloses a robust digital decoupling control method for a high-speed permanent magnet synchronous motor under a low carrier frequency ratio, and belongs to the field of quadrature-direct axis current decoupling control of a high-speed motor. The method comprises the following steps: firstly, reconstructing a high-speed motor model in a discrete domain according to a complex coefficient model of a surface-mounted permanent magnet synchronous motor (SPMSM) in a frequency domain; designing a system impedance gain modulation loop to suppress high-frequency disturbance by analyzing a mechanism of oscillation caused by current decoupling under high fundamental frequency; an internal model control theory is introduced, a reconstructed discrete domain motor model is applied, an impedance gain modulation loop is added, and a digital current controller with enhanced decoupling capability is built; the problem that a traditional controller is poor in decoupling effect when the high-speed motor operates under the low-carrier-frequency-ratio working condition is solved, the operation speed range of the high-speed motor is expanded, and the control response characteristic under the low-carrier-frequency-ratio condition is improved.

Description

Technical Field

[0001] The invention relates to a robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio, and belongs to the field of AC and DC axis current decoupling control of high-speed motors. Background Art

[0002] High-speed permanent magnet synchronous motors have the characteristics of high power density, fast speed and small moment of inertia, which make high-speed motors have faster response speed and higher control accuracy. They are widely used in many fields such as industrial control, medical equipment and household appliances. However, high-speed motors are different from ordinary motors. High-speed motors will amplify the control problems that ordinary motors can be approximately ignored, mainly current coupling and control delay. The degree of current coupling is proportional to the speed. When the base frequency is high, current coupling will cause the dynamic response of the current loop to deteriorate and the system stability margin to decrease. The phase angle delay in the control delay produces an additional coupling term that causes further cross-effects of the dq axis current. The impact of the additional coupling term on the system increases with the increase of the base frequency, resulting in the deterioration of the dynamic response of the current loop, further reducing the system stability margin, and in severe cases, causing system instability. Considering the chip computing power, switching loss and cost control issues, the control switching frequency of the inverter will not be too high, usually within tens of kHz. When the motor is running at a high base frequency, the carrier frequency ratio (the ratio of the inverter switching frequency to the base frequency) may be less than 10. Under low carrier frequency ratio, the current coupling problem of high-speed permanent magnet synchronous motor brings great challenges to the current controller.

[0003] The PMSM vector control realizes the static decoupling of the dq axis current in the dq coordinate system, but cannot eliminate the influence of the dynamic coupling between the dq axis currents. Based on the PI controller, the introduction of diagonal decoupling control can realize the dynamic decoupling between the dq axis currents. The decoupling methods include feedforward decoupling, feedback decoupling, deviation decoupling and internal model decoupling. The feedforward decoupling method and feedback decoupling method are easily affected by parameter mismatch, resulting in insufficient dynamic decoupling. The deviation decoupling method has a relatively complex implementation process. The internal model decoupling method has strong parameter robustness and is easy to adjust, but the integral link of its decoupling term will cause pre-steady-state oscillation. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a robust digital decoupling control method for a high-speed permanent magnet synchronous motor under a low carrier frequency ratio, reconstructs the precise motor model in the discrete domain, designs an impedance gain modulation loop, and establishes a high-performance current controller with enhanced current decoupling capability by introducing the internal model control principle. The steady-state pre-oscillation problem caused by the traditional internal model controller is optimized, and the parameter robustness of the current controller is enhanced.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio comprises the following steps:

[0007] Step S1: sampling the input voltage, output current, speed and rotor position angle of the three-phase winding of the high-speed motor, and obtaining the current value in the synchronous rotating coordinate system, i.e., the dq coordinate system, through coordinate transformation of the output current;

[0008] Step S2: According to the stator voltage equation of the SPMSM in the dq coordinate system, a complex coefficient model of the SPMSM in the frequency domain is established;

[0009] Step S3: Using the complex coefficient model obtained in step S2, considering the zero-order holding effect of the inverter, establish the discrete domain SPMSM model G in the dq coordinate system M (z);

[0010] Step S4: Using the discrete domain SPMSM model G obtained in step S3 M (z), considering the influence of control delay, is more in line with the actual motor operation system conditions, and the SPMSM model considering the delay influence in the discrete domain is obtained. P (z);

[0011] Step S5: To suppress the pre-steady-state oscillation phenomenon caused by internal mode decoupling at high fundamental frequency, a system impedance gain modulation loop G is designed. a (z);

[0012] Step S6: Implement the system impedance gain modulation loop G designed in step S5 a In the differential link (z), a first-order low-pass filter with a parameter τ is connected in series with the inductance term to obtain the system impedance gain modulation loop G b (z);

[0013] Step S7: Add the impedance gain modulation link obtained in step S6 to determine the discrete domain SPMSM transfer function G Pa (z) to achieve accurate reconstruction of high-speed motor models;

[0014] Step S8: Based on the discrete domain SPMSM accurate reconstruction model obtained in step S7, a current controller G with enhanced current decoupling capability is designed. c (z).

[0015] The further improvement of the technical solution of the present invention is that the specific operation of step S1 is: sampling the current output by the three-phase winding of the SPMSM, and naming i a 、i b and i c , the output current of the three-phase winding is transformed into Clark coordinates and Park coordinates to obtain the d and q axis current i in the synchronous rotating coordinate system, i.e., the dq coordinate system d 、iq .

[0016] A further improvement of the technical solution of the present invention is that the stator voltage equation of the SPMSM in the dq coordinate system in step S2 is:

[0017]

[0018] where u d 、u q is the d and q axis voltage components, i d 、i q are the d and q axis current components, L s is the winding equivalent inductance, R s is the equivalent resistance of the winding, ψ f is the permanent magnet flux, ω e is the rotor electrical angular velocity;

[0019] The specific operation of step S2 is: according to the stator voltage equation of SPMSM in the time domain, Laplace transform is performed to establish the complex coefficient model G of SPMSM in the frequency domain. M (s), the back electromotive force ω e ψ f The term is regarded as a disturbance, and the input voltage u dq (s) to output current i dq The transfer function of (s) is:

[0020]

[0021] Among them, L s is the winding equivalent inductance, R s is the winding equivalent resistance, ω e is the rotor electrical angular velocity.

[0022] The further improvement of the technical solution of the present invention is that the specific operation of step S3 is: according to the complex coefficient model of SPMSM in the frequency domain, the high-speed motor model is reconstructed in the discrete domain, and the inverter is equivalent to an ideal zero-order holder ZOH:

[0023]

[0024] Combined with the frequency domain SPMSM complex coefficient model, z-transform is performed to obtain the SPMSM discrete domain model G in the dq coordinate system. M (z), where T s is the inverter switching cycle;

[0025]

[0026] A further improvement of the technical solution of the present invention is that the specific operation of step S4 is: the control delay is connected in series on the forward channel of the current loop, causing a phase angle delay between the command voltage and the actual output voltage, and the delay angle θ d =ω e T d , the control delay in the dq coordinate system is divided into the time delay term and the phase delay term Delay time T d ;

[0027] The expression for the time delay term in the discrete domain is:

[0028]

[0029] The expression of phase angle delay in discrete domain is:

[0030]

[0031] Consider the SPMSM discrete domain model of control delay:

[0032]

[0033] in

[0034] A further improvement of the technical solution of the present invention is that the specific operation of step S5 is:

[0035] The s-domain transfer function is:

[0036] G a (s)=sL a +R a ;

[0037] Among them, L a is the impedance gain modulation loop inductance term; R a The impedance gain modulates the loop resistance term;

[0038] The expression of impedance gain modulation link in discrete domain is:

[0039]

[0040] A further improvement of the technical solution of the present invention is that: a first-order low-pass filter with a parameter τ is connected in series with the inductance term to obtain a new impedance gain modulation loop G b (z):

[0041]

[0042] A further improvement of the technical solution of the present invention is that the discrete domain SPMSM transfer function in step S7 is:

[0043]

[0044] A further improvement of the technical solution of the present invention is that: the current controller G of the step S8 that enhances the current decoupling capability c (z):

[0045]

[0046] Where α is the internal model controller parameter; H = H3(R s +jω e L s )(H1+jH2); H1=1-h0cosθ d ;

[0047]

[0048] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0049] The present invention provides an accurate reconstruction model of the discrete domain of a surface-mounted permanent magnet synchronous motor, which is closer to a motor in actual operation and reduces the error between the motor model and the actual motor.

[0050] The present invention designs a current controller with enhanced current decoupling capability, realizes dynamic and static decoupling of stator current and delay compensation. The system impedance gain modulation loop is designed to enhance the anti-disturbance capability of high-speed motors under high fundamental frequency conditions, solves the problem of pre-steady-state oscillation caused by internal model decoupling, and improves the tracking performance and parameter robustness of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a vector system block diagram of a robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio based on the present invention;

[0052] Figure 2 It is a structure diagram of the discrete domain SPMSM mathematical model in the present invention;

[0053] Figure 3 It is a structural diagram of the discrete domain current controller in the present invention. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below in conjunction with embodiments:

[0055] A robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio comprises the following steps:

[0056] Step S1: sampling the input voltage, output current, speed and rotor position angle of the three-phase winding of the high-speed motor, and obtaining the current value in the synchronous rotating coordinate system (dq coordinate system) by coordinate transformation of the input voltage and output current.

[0057] The coordinate transformation of the sampled current is as follows: the current output by the three-phase winding of the SPMSM is sampled and named i a 、i b and i c , the current output by the three-phase winding is transformed into Clark coordinates and Park coordinates to obtain the d and q axis currents i in the synchronous rotating coordinate system (dq coordinate system) d 、i q .

[0058] Step S2: According to the stator voltage equation of the SPMSM in the dq coordinate system, a complex coefficient model of the SPMSM in the frequency domain is established.

[0059] The specific steps of the complex coefficient model are as follows: First, the stator voltage equation of the SPMSM in the dq coordinate system is:

[0060]

[0061] where u d 、u q is the d and q axis voltage components, i d 、i q are the d and q axis current components, L s is the winding equivalent inductance, R s is the equivalent resistance of the winding, ψ f is the permanent magnet flux, ω e is the rotor electrical angular velocity.

[0062] According to the stator voltage equation of SPMSM in the time domain, Laplace transform is performed to establish the complex coefficient model of SPMSM in the frequency domain: the back electromotive force (ω e ψ f ) is considered as a disturbance, then the input voltage u dq (s) to output current i dq The transfer function G of (s) M (s) is:

[0063]

[0064] Step S3: Using the complex coefficient model obtained in step S2, considering the zero-order holding effect of the inverter, establish the discrete domain SPMSM model G in the dq coordinate system M (z);

[0065] The specific steps of establishing the discrete domain SPMSM model are as follows: Based on the complex coefficient model of SPMSM in the frequency domain, the high-speed motor model is reconstructed in the discrete domain. The inverter is equivalent to an ideal zero-order holder ZOH:

[0066]

[0067] Combined with the frequency domain SPMSM complex coefficient model, z-transform is performed to obtain the SPMSM discrete domain model G in the dq coordinate system. M (z), where T s is the inverter switching cycle.

[0068]

[0069] Step S4: Using the discrete domain SPMSM model G obtained in step S3 M (z), considering the influence of control delay, is more in line with the actual motor operation system conditions, and the SPMSM model considering the delay influence in the discrete domain is obtained. P (z);

[0070] Considering the influence of control delay, a motor model that is more in line with the actual motor operation system is established: the control delay is connected in series to the forward channel of the current loop, causing a phase angle delay between the command voltage and the actual output voltage. The delay angle θ d =ω e T d , the control delay in the dq coordinate system is divided into the time delay term and the phase delay term Delay time T d .

[0071] The expression for the time delay term in the discrete domain is:

[0072]

[0073] The expression of phase angle delay in discrete domain is:

[0074]

[0075] Consider the SPMSM discrete domain model of control delay:

[0076]

[0077] in

[0078] Step S5: To suppress the pre-steady-state oscillation phenomenon caused by internal mode decoupling at high fundamental frequency, a system impedance gain modulation loop G is designed. a (z);

[0079] Design the system impedance gain modulation loop G a (z) Specific steps: The s-domain transfer function is:

[0080] G a (s)=sL a +R a ;

[0081] Where L a is the impedance gain modulation loop inductance term; R a is the impedance gain modulation loop resistance term.

[0082] The expression of impedance gain modulation link in discrete domain is:

[0083]

[0084] Step S6: Implement the system impedance gain modulation loop G designed in step S5 a In the differential link (z), a first-order low-pass filter with a parameter τ is connected in series with the inductance term to obtain the system impedance gain modulation loop G b (z);

[0085] G a The steps of connecting a low-pass filter in series with the inductance term of the differential link in (z) are as follows: To realize the differential link in the impedance gain modulation link, a first-order low-pass filter with a parameter τ is connected in series with the inductance term to obtain a new impedance gain modulation link:

[0086]

[0087] Set τ to a small value so that G b (z) is closer to G a (z), aims to give full play to the role of the differential link in the impedance gain modulation link, where τ = 10μs.

[0088] Step S7: Add the impedance gain modulation link obtained in step S6 to determine the discrete domain SPMSM transfer function G Pa (z) to achieve accurate reconstruction of high-speed motor models;

[0089] The specific process of accurate reconstruction of the high-speed motor model: Considering the control delay and the inverter zero-order hold effect, the discrete domain SPMSM transfer function with the impedance gain modulation link is:

[0090]

[0091] Step S8: Based on the discrete domain SPMSM accurate reconstruction model obtained in step S7, a current controller G with enhanced current decoupling capability is designed. c (z).

[0092] Design current controller G c (z) Specific process: Based on the accurate reconstruction model of discrete domain SPMSM, a current controller G is designed to enhance the current decoupling capability. c (z), achieving delay compensation. The controller contains a first-order low-pass filter, so G cThe inductance term of the impedance gain modulation link in (z) does not need to be connected in series with other low-pass filters.

[0093]

[0094] Where α is the internal model controller parameter; H = H3(R s +jω e L s )(H1+jH2); H1=1-h0cosθ d ;

[0095]

[0096] Example

[0097] Figure 1 This is a vector system block diagram of a robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio based on the present invention, wherein the orange background part is the detected electrical parameters and rotor position signals used in the present invention. The blue background part is the current controller for enhancing the decoupling effect proposed by the present invention.

[0098] Figure 1 The orange background part in the middle is the electrical parameters and rotor position signal for detecting the input voltage, output current and speed of the three-phase winding of the high-speed motor. The sampled three-phase winding current is named i a 、i b and i c , the current output by the three-phase winding is transformed into Clark coordinates and Park coordinates to obtain the d and q axis currents i in the synchronous rotating coordinate system (dq coordinate system) d 、i q .

[0099] The input voltage, output current, speed and rotor position angle of the three-phase winding of the high-speed motor are sampled, and the input voltage and output current are transformed into the current value in the synchronous rotating coordinate system (dq coordinate system).

[0100] The coordinate transformation of the sampled current is as follows: The current output by the three-phase winding of the SPMSM is sampled and named i a 、i b and i c , the current output by the three-phase winding is transformed into Clark coordinates and Park coordinates to obtain the d and q axis currents i in the synchronous rotating coordinate system (dq coordinate system) d 、i q .

[0101] According to the stator voltage equation of SPPMSM in dq coordinate system, the complex coefficient model of SPPMSM in frequency domain is established. dq (s) to output current idq The transfer function G of (s) M (s) is:

[0102]

[0103] Where L s is the winding equivalent inductance, R s is the winding equivalent resistance, ω e is the rotor electrical angular velocity.

[0104] Figure 2 It is based on the discrete domain SPMSM mathematical model structure diagram of the present invention. According to the complex coefficient model of SPMSM in the frequency domain, the high-speed motor model is reconstructed in the discrete domain. The inverter is equivalent to an ideal zero-order holder, and the frequency domain SPMSM complex coefficient model is z-transformed to obtain the SPMSM discrete domain model G in the dq coordinate system. M (z), where T s is the inverter switching cycle.

[0105]

[0106] Considering the influence of control delay, the time delay term and phase angle delay term are discretized. The expression of the time delay term in the discrete domain is:

[0107]

[0108] The expression of phase angle delay in discrete domain is:

[0109]

[0110] Multiply by the discrete domain motor model G M (z), we get the accurate SPMSM discrete domain model considering the influence of control delay:

[0111]

[0112] in

[0113] In order to suppress the pre-steady-state oscillation phenomenon caused by the integral term in the internal mode decoupling at high fundamental frequency, a system impedance gain modulation loop is designed, and the s-domain transfer function is:

[0114] G a (s)=sL a +R a

[0115] Among them, L a is the impedance gain modulation loop inductance term; R a is the impedance gain modulation loop resistance term.

[0116] The expression of impedance gain modulation link in discrete domain is:

[0117]

[0118] In order to realize the differential link in the impedance gain modulation link, a first-order low-pass filter with a parameter of τ is connected in series with the inductance term to obtain a new impedance gain modulation link:

[0119]

[0120] Set τ to a small value so that G b (z) is closer to G a (z), aims to give full play to the role of the differential link in the impedance gain modulation link, where τ = 10μs.

[0121] Considering the control delay and the inverter zero-order hold effect, the discrete domain SPMSM transfer function G with impedance gain modulation is added. Pa (z) is:

[0122]

[0123] Figure 3 Based on the discrete domain current controller structure diagram of the present invention, according to the accurate reconstruction model of discrete domain SPMSM, a current controller G with enhanced current decoupling capability is designed. c (z), achieving delay compensation. The controller contains a first-order low-pass filter, so G c The inductance term of the impedance gain modulation link in (z) does not need to be connected in series with other low-pass filters.

[0124]

[0125] Where α is the internal model controller parameter; H = H3(R s +jω e L s )(H1+jH2); H1=1-h0cosθ d ;

[0126]

[0127] The present invention aims at the problem that when a permanent magnet synchronous motor runs at high speed and low carrier frequency ratio, current coupling and control delay will seriously affect the control stability and dynamic response capability, and even cause system instability in severe cases. Based on the traditional current decoupling method, a robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio is proposed. By reconstructing an accurate high-speed motor model in the discrete domain, introducing the internal model control theory, designing the system impedance gain modulation loop, and building a digital current controller with enhanced decoupling capability. The system stability and control response characteristics under low carrier frequency ratio are improved, the problem of pre-steady-state oscillation caused by internal model decoupling is solved, and the tracking performance and parameter robustness of the control system are improved.

[0128] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here. The specific implementation methods described above further explain the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A robust digital decoupling control method for high-speed permanent magnet synchronous motor under low carrier frequency ratio, characterized in that The steps include: Step S1: sampling the input voltage, output current, speed and rotor position angle of the three-phase winding of the high-speed motor, and obtaining the current value in the synchronous rotating coordinate system, i.e., the dq coordinate system, through coordinate transformation of the output current; Step S2: According to the stator voltage equation of the SPMSM in the dq coordinate system, a complex coefficient model of the SPMSM in the frequency domain is established; Step S3: Using the complex coefficient model obtained in step S2, considering the zero-order holding effect of the inverter, establish the discrete domain SPMSM model G in the dq coordinate system M (z); Step S4: Using the discrete domain SPMSM model G obtained in step S3 M (z), considering the influence of control delay, is more in line with the actual motor operation system conditions, and the SPMSM model considering the delay influence in the discrete domain is obtained. P (z); Step S5: To suppress the pre-steady-state oscillation phenomenon caused by internal mode decoupling at high fundamental frequency, a system impedance gain modulation loop G is designed. a (z); Step S6: Implement the system impedance gain modulation loop G designed in step S5 a In the differential link (z), a first-order low-pass filter with a parameter τ is connected in series with the inductance term to obtain the system impedance gain modulation loop G b (z); Step S7: Add the impedance gain modulation link obtained in step S6 to determine the discrete domain SPMSM transfer function G Pa (z) to achieve accurate reconstruction of high-speed motor models; Step S8: Based on the discrete domain SPMSM accurate reconstruction model obtained in step S7, a current controller G with enhanced current decoupling capability is designed. c (z).

2. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio according to claim 1 is characterized in that: The specific operation of step S1 is: sampling the current output by the three-phase winding of the SPMSM, and naming i a 、i b and i c , the output current of the three-phase winding is transformed into Clark coordinates and Park coordinates to obtain the d and q axis current i in the synchronous rotating coordinate system, i.e., the dq coordinate system d 、i q .

3. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio according to claim 1 is characterized in that: The stator voltage equation of the SPMSM in the dq coordinate system in step S2 is: where u d 、u q is the d and q axis voltage components, i d 、i q are the d and q axis current components, L s is the winding equivalent inductance, R s is the equivalent resistance of the winding, ψ f is the permanent magnet flux, ω e is the rotor electrical angular velocity; The specific operation of step S2 is: according to the stator voltage equation of SPMSM in the time domain, Laplace transform is performed to establish the complex coefficient mathematical model G of SPMSM in the frequency domain. M (s), the back electromotive force ω e ψ f The term is regarded as a disturbance, and the input voltage u dq (s) to output current i dq The transfer function of (s) is: Among them, L s is the winding equivalent inductance, R s is the winding equivalent resistance, ω e is the rotor electrical angular velocity.

4. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio according to claim 1 is characterized in that: The specific operation of step S3 is: according to the complex coefficient model of SPMSM in the frequency domain, the high-speed motor model is reconstructed in the discrete domain, and the inverter is equivalent to an ideal zero-order holder ZOH: Combined with the frequency domain SPMSM complex coefficient model, z-transform is performed to obtain the SPMSM discrete domain model G in the dq coordinate system. M (z), where T s is the inverter switching cycle; 5. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio according to claim 1 is characterized in that: The specific operation of step S4 is: control the delay to be connected in series on the forward channel of the current loop, causing a phase angle delay between the command voltage and the actual output voltage, and the delay angle θ d =ω e T d , the control delay in the dq coordinate system is divided into the time delay term and the phase delay term Delay time T d ; The expression for the time delay term in the discrete domain is: The expression of phase angle delay in discrete domain is: Consider the SPMSM discrete domain model of control delay: in 6. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio according to claim 1 is characterized in that: The specific operations of step S5 are: The s-domain transfer function is: G a (s)=sL a +R a ; Among them, L a is the impedance gain modulation loop inductance term; R a The impedance gain modulates the loop resistance term; The expression of impedance gain modulation link in discrete domain is:

7. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio according to claim 1 is characterized in that: The specific operation of step S6 is: connect a first-order low-pass filter with a parameter τ in series with the inductance term to obtain a new impedance gain modulation loop G b (z):

8. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor under low carrier frequency ratio according to claim 1 is characterized in that: The discrete domain SPMSM transfer function in step S7 is:

9. The robust digital decoupling control method for a high-speed permanent magnet synchronous motor at a low carrier frequency ratio according to claim 1, characterized in that: The current controller G of step S8 that enhances the current decoupling capability c (z): Where α is the internal model controller parameter; H = H3(R s +jω e L s )(H1+jH2); H1=1-h0cosθ d ; H2=-h0 sinθ d ;

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