A dual three-phase motor control system and method for single-phase open circuit fault

Abstract

The present invention discloses a dual three-phase motor control system and method for single-phase open circuit fault, the control system includes a speed control module, a current distributor, a torque space current control module, an anti-interference module, a first voltage rotation conversion module, a harmonic space current reference value generation module, a harmonic space current control module, a second voltage rotation conversion module, a voltage conversion module, a current conversion module, a first current rotation conversion module, a second current rotation conversion module, a first pulse width modulation module, a second pulse width modulation module, a first three-phase inverter, a second three-phase inverter, an encoder, a speed calculator, and a dual three-phase motor. The control system and the working method of the present invention are suitable for healthy working conditions and fault working conditions, can automatically switch between the two seamlessly without the need for diagnostic operations such as fault identification and positioning, and can achieve different optimization goals after the dual three-phase motor system fails by adjusting the current amplitude ratio and phase offset of the two sets of three-phase windings.

Description

Technical Field

[0001] The present invention relates to the field of multi-phase motor control technology and fault-tolerant control, and in particular to a dual three-phase motor control system and method for single-phase open circuit fault. Background Art

[0002] Dual three-phase motors are popular in electrified transportation, electric aircraft and other fields with strict reliability requirements due to their excellent electrical fault tolerance. They are also popular in remote places such as offshore wind power (where maintenance is difficult and costly). Fault tolerance control of multi-phase motor drive systems has always been a research hotspot. Thanks to the additional degrees of freedom of dual three-phase motors compared to traditional three-phase motors, dual three-phase motor drive systems can achieve torque ripple-free fault tolerance performance by simply changing the control method in software without changing the hardware connection method.

[0003] For single-phase open circuit faults, the existing dual three-phase motor fault-tolerant control systems based on vector control are mainly divided into the following two categories: 1) Reduced-order decoupling transformation matrix. Under healthy conditions, traditional vector control maps six-phase physical quantities to two sets of two-dimensional decoupling spaces, namely torque space and harmonic space, through the vector space decoupling (VSD) method. Considering that the phase current value is zero due to a single-phase open circuit fault, continuing to use the original full-order decoupling transformation matrix will cause the currents in the torque space and harmonic space to be coupled with each other and cannot be adjusted independently. The reduced-order decoupling transformation matrix is ​​used to re-map the remaining 5-phase currents to mutually decoupled two-dimensional space and one-dimensional space to achieve decoupling control. 2) Change the harmonic space current reference value. Due to the mutual coupling of different subspaces under fault conditions, there is an inherent correlation between the torque space current and the harmonic space current, and the current closed-loop control objectives of the two conflict. In order to ensure torque stability, the second method adjusts the harmonic space current reference value according to the constraint that the fault phase current is zero to achieve fault-tolerant control.

[0004] The above two traditional fault-tolerant control methods are based on the concept of fault diagnosis before fault-tolerant control, which separates the control design of healthy conditions and fault conditions, and the effectiveness of fault-tolerant control methods often depends on fault diagnosis information. This leads to the following two problems: on the one hand, the effectiveness of traditional fault-tolerant control methods depends on the performance of fault diagnosis, which increases the complexity of system control; on the other hand, traditional fault-tolerant control methods cannot achieve seamless switching between healthy and faulty conditions, and have inherent problems such as fault diagnosis delay. With the goal of universal control methods under different working conditions, how to achieve passive and automatic fault-tolerant control without fault diagnosis has become an urgent problem to be solved in the control of dual three-phase motor drive systems and their widespread industrial applications. Summary of the invention

[0005] The purpose of the present invention is to provide a dual three-phase motor control system and method for single-phase open circuit faults, utilizing the self-healing ability of the dual three-phase motor drive system for single-phase open circuit faults, comprehensively considering the system's automatic fault tolerance during faults and system optimization after faults, to achieve universal control of the dual three-phase motor under healthy conditions and fault conditions.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A dual three-phase motor control system and method for single-phase open circuit fault, the control system includes a speed control module, a current distributor, a torque space current control module, an anti-interference module, a first voltage rotation conversion module, a harmonic space current reference value generation module, a harmonic space current control module, a second voltage rotation conversion module, a voltage conversion module, a current conversion module, a first current rotation conversion module, a second current rotation conversion module, a first pulse width modulation module, a second pulse width modulation module, a first three-phase inverter, a second three-phase inverter, an encoder, a speed calculator, and a dual three-phase motor.

[0008] Furthermore, the input of the speed control module is the speed reference value and the actual speed calculation value of the speed calculation module, and the output is the torque reference value.

[0009] The input of the current distributor is a torque reference value, and the output is a torque space current reference value.

[0010] The input of the torque space current control module is the torque space current reference value and the torque space current actual value, and the output is the torque space control voltage.

[0011] The input of the anti-disturbance module is the actual value of the torque space current and the torque space reference voltage, and the output is the torque space compensation voltage.

[0012] The input of the first voltage rotation conversion module is the torque space reference voltage and the rotor electrical angle, and the output is the torque space reference voltage in a stationary coordinate system.

[0013] The input of the harmonic space current reference value generation module is the torque space current reference value, the current amplitude ratio of the two sets of three-phase windings, and the current phase offset of the two sets of three-phase windings, and the output is the harmonic space current reference value.

[0014] The input of the harmonic space current control module is the harmonic space current reference value and the harmonic space current actual value, and the output is the harmonic space reference voltage.

[0015] The input of the second voltage rotation conversion module is the harmonic space reference voltage and the rotor electrical angle, and the output is the harmonic space reference voltage under stationary coordinates.

[0016] The input of the voltage conversion module is the torque space reference voltage and the harmonic space reference voltage under the stationary coordinates, and the output is the reference voltage components of the two sets of three-phase windings under the stationary coordinates.

[0017] The input of the current conversion module is the six-phase current sampling value, and the output is the torque space current actual value and the harmonic space current actual value in the stationary coordinate system.

[0018] The input of the first current rotation transformation module is the actual value of the torque space current and the rotor electrical angle in a stationary coordinate system, and the output is the actual value of the torque space current in a synchronous rotating coordinate system.

[0019] The input of the second current rotation transformation module is the actual value of the harmonic space current and the rotor electrical angle in a stationary coordinate system, and the output is the actual value of the harmonic space current in a synchronous rotating coordinate system.

[0020] The input of the first pulse width modulation module is the reference voltage component of the first set of three-phase windings in a stationary coordinate system, and the output is a first group of pulse width modulation signals.

[0021] The input of the second pulse width modulation module is the reference voltage component of the second set of three-phase windings in the stationary coordinate system, and the output is a second group of pulse width modulation signals.

[0022] The input of the first three-phase inverter is a first set of pulse width modulation signals, and the output is connected to the first set of three-phase windings of the dual three-phase motor.

[0023] The input of the second three-phase inverter is a second set of pulse width modulation signals, and the output is connected to the second set of three-phase windings of the dual three-phase motor.

[0024] The dual three-phase motor contains two sets of three-phase windings, and each set of three-phase windings is usually star-connected, wherein the two neutral points are isolated from each other. The first set of three-phase windings is called ABC winding, and the second set of three-phase windings is called DEF winding.

[0025] Furthermore, the working method of the control system comprises the following steps:

[0026] Step 1: Collect the angle signal measured by the encoder, obtain the rotor electrical angle and use the speed calculator to get the actual speed value; use the current sensor to collect the current signal and send it to the current conversion module.

[0027] Step 2: Use the first current rotation transformation module and the second current rotation transformation module to process the output result of the current conversion module to obtain the actual current value in the torque space and harmonic space under the synchronous rotating coordinate.

[0028] Step 3: Set the speed reference value, combine the actual speed value in step 1, and obtain the torque reference value through the speed control module; input the torque reference value into the current distributor to obtain the torque space current reference value.

[0029] Step 4: Send the torque space current reference value in step 3 and the torque space current actual value in step 2 to the torque space current control module to calculate the torque space control voltage; use the anti-interference module to calculate the torque space compensation voltage, and finally add the control voltage and compensation voltage of the torque space to obtain the torque space reference voltage in the synchronous rotating reference coordinate system, and send it to the first voltage rotation transformation module to obtain the torque space reference voltage in the stationary coordinate system.

[0030] Step 5: According to the system operating conditions and optimization objectives, the current amplitude ratio and phase offset of the two sets of three-phase windings are reasonably set, and the harmonic space current reference value is calculated by the harmonic space current reference value generation module in combination with the torque space current reference value in step 3.

[0031] Step 6: Input the actual value of the harmonic space current in step 2 and the reference value of the harmonic space current in step 5 into the harmonic space current control module, and the calculation result is passed through the second voltage rotation transformation module to obtain the harmonic space reference voltage under the stationary coordinate.

[0032] Step 7: The voltage conversion module processes the torque space reference voltage in step 4 and the harmonic space voltage reference value in step 6 to obtain the reference voltage components of the ABC winding and the DEF winding in the stationary coordinate.

[0033] Step 8: The ABC winding reference voltage component obtains the corresponding power device drive signal through the first pulse width modulation module, and the DEF winding reference voltage component obtains the corresponding power device drive signal through the second pulse width modulation module; the two sets of drive signals are respectively sent to the first three-phase inverter and the second three-phase inverter to jointly drive the dual three-phase motor.

[0034] Furthermore, the harmonic space current reference value generating module, whose output result harmonic space current reference value is determined by the torque space current reference value, the current amplitude ratio of the two sets of three-phase windings, and the current phase offset of the two sets of three-phase windings, can be expressed by the following formula:

[0035]

[0036] Among them, i z1_ref and i z2_ref are the current reference values ​​of the harmonic space z1 axis and z2 axis respectively; i d_ref and i q_ref are the current reference values ​​of the d-axis and q-axis in the torque space respectively; k and θ shiftThey are respectively the current amplitude ratio of the two sets of three-phase windings and the current phase offset of the two sets of three-phase windings.

[0037] Furthermore, the harmonic space current control module includes a first adder, a second adder, a first notch filter, a second notch filter, a first PI controller, and a second PI controller.

[0038] The positive input end of the first adder is connected to the harmonic space z1 axis current reference value, and the reverse input end is connected to the harmonic space z1 axis current actual value. The output end of the first adder is connected to the input end of the first notch filter; the output end of the first notch filter is connected to the input end of the first PI controller, and the output end of the first PI controller is the harmonic space z1 axis reference voltage.

[0039] The positive input end of the second adder is connected to the harmonic space z2 axis current reference value, and the reverse input end is connected to the harmonic space z2 axis current actual value, the output end of the second adder is connected to the input end of the second notch filter, the output end of the second notch filter is connected to the input end of the second PI controller, and the output end of the second PI controller is the harmonic space z2 axis reference voltage.

[0040] Furthermore, in order to filter out the AC component of a specific frequency under fault conditions, the center frequency of the trap in the harmonic space current control module is twice the fundamental electrical frequency. The trap G(s) of the harmonic space current control module can be expressed as:

[0041]

[0042] Where s is the Laplace operator, ω c is the center frequency of the notch filter, ξ is the damping ratio of the notch filter. The center frequency of the notch filter should be set to twice the fundamental electrical frequency ω c =2ω e =2n p ω n .n p is the number of motor pole pairs, ω n is the actual speed value.

[0043] Furthermore, the anti-interference module is characterized in that the torque space compensation voltage is calculated using the actual value of the torque space current and the torque space reference voltage, thereby increasing the anti-interference performance of the torque space under fault conditions. Considering the simplicity of implementation, only the actual value of the torque space current is used to obtain the torque space compensation voltage, and the formula is as follows:

[0044] u comp_dq =-(R active -R s )i dq

[0045] Among them, u comp_dq and i dq are the torque space compensation voltage and the actual value of torque space current, R s is the torque space stator resistance, R active It is the torque space active resistor. Increasing its value can increase the torque space anti-interference ability.

[0046] Furthermore, the control system and working method are applicable to healthy operating conditions and faulty operating conditions, and can automatically switch between the two seamlessly without the need for diagnostic operations such as fault identification and location.

[0047] Furthermore, the control system and working method achieve different optimization goals after a dual three-phase motor system fails by adjusting the current amplitude ratio and phase offset of the two sets of three-phase windings.

[0048] Beneficial effects of the present invention:

[0049] 1. The universal control system and method proposed in the present invention can realize automatic fault-tolerant control when a single-phase open-circuit fault occurs in a dual three-phase motor system without the need for fault diagnosis information, thereby realizing seamless switching between healthy working conditions and faulty working conditions;

[0050] 2. The universal control system and method proposed in the present invention can realize various optimization strategies after system failure by adjusting the current amplitude ratio and phase offset of two sets of three-phase windings, and realize strategies such as minimum copper loss and maximum torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described below in conjunction with the accompanying drawings.

[0052] Figure 1 It is a circuit diagram of the control system of the present invention;

[0053] Figure 2 This is the working method flow of the control system of the present invention;

[0054] Figure 3 This is the experimental result diagram of the traditional control method without considering fault tolerance;

[0055] Figure 4 It is a diagram of experimental results of the universal control system of the present invention. DETAILED DESCRIPTION

[0056] 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.

[0057] A dual three-phase motor control system and method for single-phase open circuit fault, the control system includes a speed control module 1, a current distributor 2, a torque space current control module 3, an anti-interference module 4, a first voltage rotation conversion module 5, a harmonic space current reference value generation module 6, a harmonic space current control module 7, a second voltage rotation conversion module 8, a voltage conversion module 9, a current conversion module 14, a first current rotation conversion module 12, a second current rotation conversion module 13, a first pulse width modulation module 10, a second pulse width modulation module 11, a first three-phase inverter 15, a second three-phase inverter 16, an encoder 18, a speed calculator 19, and a dual three-phase motor 17.

[0058] The input of the speed control module 1 is the speed reference value and the actual speed calculation value of the speed calculator 19, and the output is the torque reference value; the input of the current distributor 2 is the torque reference value, and the output is the torque space current reference value; the input of the torque space current control module 3 is the torque space current reference value and the torque space current actual value, and the output is the torque space control voltage; the input of the anti-interference module 4 is the torque space current actual value and the torque space reference voltage, and the output is the torque space compensation voltage.

[0059] The input of the first voltage rotation transformation module 5 is the torque space reference voltage and the rotor electrical angle, and the output is the torque space reference voltage in the stationary coordinate system; the input of the harmonic space current reference value generation module 6 is the torque space current reference value, the current amplitude ratio of the two sets of three-phase windings, and the current phase offset of the two sets of three-phase windings, and the output is the harmonic space current reference value.

[0060] The input of the harmonic space current control module 7 is the harmonic space current reference value and the actual value of the harmonic space current, and the output is the harmonic space reference voltage. The harmonic space current control module 7 includes a first adder, a second adder, a first notch filter, a second notch filter, a first PI controller, and a second PI controller. The function of the first trap filter and the second trap filter is to filter out the AC component of a specific frequency under fault conditions. The positive input end of the first adder is connected to the harmonic space z1 axis current reference value, and its reverse input end is connected to the harmonic space z1 axis current actual value, and the output end of the first adder is connected to the input end of the first trap filter; the output end of the first trap filter is connected to the input end of the first PI controller, and the output end of the first PI controller is the harmonic space z1 axis reference voltage; the positive input end of the second adder is connected to the harmonic space z2 axis current reference value, and its reverse input end is connected to the harmonic space z2 axis current actual value, the output end of the second adder is connected to the input end of the second trap filter, the output end of the second trap filter is connected to the input end of the second PI controller, and the output end of the second PI controller is the harmonic space z2 axis reference voltage.

[0061] The input of the second voltage rotation transformation module 8 is the harmonic space reference voltage and the rotor electrical angle, and the output is the harmonic space reference voltage under stationary coordinates; the input of the voltage conversion module 9 is the torque space reference voltage and the harmonic space reference voltage under stationary coordinates, and the output is the reference voltage components of the two sets of three-phase windings under stationary coordinates.

[0062] The input of the current conversion module 14 is the six-phase current sampling value, and the output is the torque space current actual value and the harmonic space current actual value in the stationary coordinate system; the input of the first current rotation transformation module 12 is the torque space current actual value and the rotor electrical angle in the stationary coordinate system, and the output is the torque space current actual value in the synchronous rotating coordinate system; the input of the second current rotation transformation module 13 is the harmonic space current actual value and the rotor electrical angle in the stationary coordinate system, and the output is the harmonic space current actual value in the synchronous rotating coordinate system.

[0063] The input of the first pulse width modulation module 10 is the reference voltage component of the first set of three-phase windings in the stationary coordinate system, and the output is the first set of pulse width modulation signals; the input of the second pulse width modulation module 11 is the reference voltage component of the second set of three-phase windings in the stationary coordinate system, and the output is the second set of pulse width modulation signals.

[0064] The input of the first three-phase inverter 15 is the first set of pulse width modulation signals, and the output is connected to the first set of three-phase windings of the dual three-phase motor 17; the input of the second three-phase inverter 16 is the second set of pulse width modulation signals, and the output is connected to the second set of three-phase windings of the dual three-phase motor 17.

[0065] The dual three-phase motor 17 contains two sets of three-phase windings, each of which is usually star-connected, with two neutral points isolated from each other. The first set of three-phase windings is called ABC windings, and the second set of three-phase windings is called DEF windings.

[0066] like Figure 2 As shown, a dual three-phase motor control system and a working method thereof for a single-phase open circuit fault include the following steps:

[0067] Step 1: Collect the angle signal measured by the encoder 18 to obtain the rotor electrical angle θ e And use the speed calculator 19 to get the actual speed value ω n ; Use current sensor to collect current signal i A ,i B ,i C ,i D ,i E ,i F And send it to the current conversion module 14, and its conversion process can be expressed as:

[0068]

[0069] Among them, the subscript ABCDEF of i represents the current sampling value of the six-phase static coordinate, the subscript αβ represents the torque space component under the static coordinate, and the subscript xy represents the harmonic space component under the static coordinate.

[0070] Step 2: Use the first current rotation transformation module 12 and the second current rotation transformation module 13 to process the output result of the current conversion module 14 to obtain the torque space i under the synchronous rotation coordinate dq and actual value of harmonic space current i z1z2 , where the transformation process from the stationary coordinate system to the synchronously rotating coordinate system can be expressed as:

[0071]

[0072] Among them, θ e is the rotor electrical angle of step one.

[0073] Step 3: Set the speed reference value ωn_ref, and combine the actual speed value ωn in step 1 to obtain the torque reference value T through the speed control module 1 based on the PI controller. e_ref ; Input the torque reference value into the current distributor 2 to obtain the torque space current reference value i dq_ref One simple method is to set the direct-axis current to zero, and the torque current reference value calculation process is as follows:

[0074]

[0075] Among them, n p is the number of motor pole pairs, ψ m is the rotor permanent magnet flux, L D and L Q are the direct-axis and quadrature-axis inductances in the torque space, respectively.

[0076] Step 4: Set the torque space current reference value i in step 3 dq_ref and the actual value of torque space current i in step 2 dq It is sent to the torque space current control module 3 based on the PI controller to calculate the torque space control voltage u dq At the same time, the anti-disturbance module 4 is used to calculate the torque space compensation voltage u comp_dq Finally, the control voltage u of the torque space dq And the compensation voltage rotation conversion module compensation voltage u comp_dq Add together to get the torque space reference voltage u in the synchronous rotating reference coordinate system dq_ref , and sent to the first voltage rotation transformation module 5 to obtain the torque space reference voltage u under the stationary coordinate αβ_ref , where the compensation voltage calculation process is as follows:

[0077]

[0078] Among them, u comp_dq and i dq are the torque space compensation voltage and the actual value of torque space current, R s is the torque space stator resistance, R active is the torque space active resistor. Increasing its value can increase the torque space anti-interference ability. The torque space reference voltage can be expressed as:

[0079]

[0080] Then the calculation process of the torque space reference voltage under stationary coordinates is:

[0081]

[0082] Step 5: Reasonably set the current amplitude ratio k and phase offset θ of the two sets of three-phase windings according to the system working conditions shift , combined with the torque space current reference value i in step 3 dq_ref The harmonic space current reference value i is calculated by the harmonic space current reference value generation module 6. z1z2_ref .

[0083]

[0084] Among them, i z1_ref and i z2_ref are the current reference values ​​of the harmonic space z1 axis and z2 axis respectively; i d_ref and i q_ref are the current reference values ​​of the d-axis and q-axis in the torque space, respectively. k and θ shift are the current amplitude ratio of the two sets of three-phase windings and the current phase offset of the two sets of three-phase windings, which are generally related to the system optimization target. In this embodiment, k=0 and θ are taken respectively. shift =0, thus achieving the goal of optimizing the maximum torque after a fault.

[0085] Step 6: The actual value of the harmonic space current i in step 2 z1z2 and the harmonic space current reference value i in step 5 z1z2_ref Input to the harmonic space current control module 7, the output result is u z1z2_ref The harmonic space reference voltage u under the stationary coordinates is obtained through the second voltage rotation transformation module 8. xy_ref The trap G(s) of the harmonic space current control module 7 can be expressed as:

[0086]

[0087] Where s is the Laplace operator, ω cis the center frequency of the notch filter, ξ is the damping ratio of the notch filter. The center frequency of the notch filter should be set to twice the fundamental electrical frequency ω c =2ω e =2n p ω n , the damping ratio of the notch filter is generally 0.707. The harmonic space reference voltage under the stationary coordinate is expressed as

[0088]

[0089] Step 7: The voltage conversion module 9 processes the torque space reference voltage u in step 4 αβ_ref And the harmonic space voltage u in step 6 xy_ref The reference value obtains the reference voltage components of the ABC winding and the DEF winding in the stationary coordinate.

[0090]

[0091] Step 8: ABC winding reference voltage component u α1β1_ref The corresponding power device drive signal is obtained through the first pulse width modulation module 10, and the DEF winding reference voltage component u α2β2_ref The corresponding power device driving signal is obtained through the second pulse width modulation module 11; the two groups of driving signals are respectively sent to the first three-phase inverter 15 and the second three-phase inverter 16 to jointly drive the dual three-phase motor 17.

[0092] experiment:

[0093] The experiment is based on a dual three-phase permanent magnet synchronous motor drive platform, and the experimental results of the dual three-phase motor control system and its method for single-phase open circuit fault are described. The parameters of the dual three-phase permanent magnet synchronous motor drive system are shown in the following table:

[0094]

[0095] The motor speed in the experiment is 300 rpm. Figure 3 The traditional control method does not consider fault tolerance design. When an open circuit fault occurs in phase F, an AC component appears in the dq-axis current of the torque space, which in turn causes torque ripple. Figure 4 A general control method suitable for single-phase open circuit fault is proposed. Under healthy conditions, the dq axis current waveform and torque waveform in the torque space remain constant, which is consistent with Figure 3The control performance is similar, indicating that the proposed control method does not affect the system control performance under healthy conditions. When an open-circuit fault occurs in phase F, the dq-axis current waveform in the torque space remains constant without fluctuation. The proposed control method achieves torque ripple-free fault-tolerant control performance without relying on fault information. It is worth noting that the proposed control method can achieve seamless switching between healthy conditions and fault conditions, avoiding the delay in fault diagnosis in traditional fault-tolerant control methods. Figure 3 and Figure 4 The effectiveness of a dual three-phase motor control system and method for single-phase open circuit fault of the present invention is illustrated.

[0096] 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 invention. 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.

[0097] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A dual three-phase motor control system for single-phase open circuit fault, characterized in that: The control system comprises a speed control module (1), a current distributor (2), a torque space current control module (3), an anti-interference module (4), a first voltage rotation conversion module (5), a harmonic space current reference value generation module (6), a harmonic space current control module (7), a second voltage rotation conversion module (8), a voltage conversion module (9), a current conversion module (14), a first current rotation conversion module (12), a second current rotation conversion module (13), a first pulse width modulation module (10), a second pulse width modulation module (11), a first three-phase inverter (15), a second three-phase inverter (16), an encoder (18), a speed calculator (19), and a dual three-phase motor (17); The input of the speed control module (1) is a speed reference value and an actual speed calculation value of the speed calculation module, and the output is a torque reference value; The input of the current distributor (2) is a torque reference value, and the output is a torque space current reference value; The input of the torque space current control module (3) is a torque space current reference value and a torque space current actual value, and the output is a torque space control voltage; The input of the anti-disturbance module (4) is the actual value of the torque space current and the torque space reference voltage, and the output is the torque space compensation voltage; The input of the first voltage rotation conversion module (5) is the torque space reference voltage and the rotor electrical angle, and the output is the torque space reference voltage in a stationary coordinate system; The input of the harmonic space current reference value generation module (6) is the torque space current reference value, the current amplitude ratio of the two sets of three-phase windings, and the current phase offset of the two sets of three-phase windings, and the output is the harmonic space current reference value; The input of the harmonic space current control module (7) is the harmonic space current reference value and the harmonic space current actual value, and the output is the harmonic space reference voltage; The input of the second voltage rotation conversion module (8) is the harmonic space reference voltage and the rotor electrical angle, and the output is the harmonic space reference voltage in a stationary coordinate; The input of the voltage conversion module (9) is the torque space reference voltage and the harmonic space reference voltage under the stationary coordinate, and the output is the reference voltage components of the two sets of three-phase windings under the stationary coordinate; The input of the current conversion module (14) is the six-phase current sampling value, and the output is the torque space current actual value and the harmonic space current actual value in the stationary coordinate system; The input of the first current rotation transformation module (12) is the actual value of the torque space current and the rotor electrical angle in a stationary coordinate system, and the output is the actual value of the torque space current in a synchronous rotating coordinate system; The input of the second current rotation transformation module (13) is the actual value of the harmonic space current and the rotor electrical angle in a stationary coordinate system, and the output is the actual value of the harmonic space current in a synchronous rotating coordinate system; The input of the first pulse width modulation module (10) is a reference voltage component of a first set of three-phase windings in a stationary coordinate system, and the output is a first set of pulse width modulation signals; The input of the second pulse width modulation module (11) is a reference voltage component of a second set of three-phase windings in a stationary coordinate system, and the output is a second set of pulse width modulation signals; The input of the first three-phase inverter (15) is a first set of pulse width modulation signals, and the output is connected to the first set of three-phase windings of the dual three-phase motor (17); The input of the second three-phase inverter (16) is a second set of pulse width modulation signals, and the output is connected to the second set of three-phase windings of the dual three-phase motor (17); The dual three-phase motor (17) comprises two sets of three-phase windings, each set of three-phase windings is star-connected, wherein the two neutral points are isolated from each other, the first set of three-phase windings is called ABC windings, and the second set of three-phase windings is called DEF windings.

2. A dual three-phase motor control system for single-phase open circuit fault according to claim 1, characterized in that: The working method of the control system comprises the following steps: Step 1: Collecting the angle signal measured by the encoder (18), obtaining the rotor electrical angle and using the speed calculator (19) to obtain the actual speed value; using the current sensor to collect the current signal and send it to the current conversion module (14); Step 2: using the first current rotation transformation module (12) and the second current rotation transformation module (13) to process the output result of the current conversion module (14) to obtain the actual current value in the torque space and the harmonic space under the synchronous rotation coordinate; Step 3: Setting the speed reference value, combining the speed actual value in step 1, and obtaining the torque reference value through the speed control module (1); Inputting the torque reference value into the current distributor (2) to obtain a torque space current reference value; Step 4: Send the torque space current reference value in step 3 and the torque space current actual value in step 2 to the torque space current control module (3) to calculate the torque space control voltage; use the anti-disturbance module (4) to calculate the torque space compensation voltage, and finally add the torque space control voltage and the compensation voltage to obtain the torque space reference voltage in the synchronous rotating reference coordinate system, and send it to the first voltage rotation transformation module (5) to obtain the torque space reference voltage in the stationary coordinate system; Step 5: According to the system operating conditions and optimization objectives, the current amplitude ratio and phase offset of the two sets of three-phase windings are reasonably set, and the harmonic space current reference value is calculated by the harmonic space current reference value generation module (6) in combination with the torque space current reference value in step 3; Step six: inputting the actual value of the harmonic space current in step two and the reference value of the harmonic space current in step five into a harmonic space current control module (7), and the calculation result thereof is passed through a second voltage rotation transformation module (8) to obtain a harmonic space reference voltage under a stationary coordinate; Step 7: The voltage conversion module (9) processes the torque space reference voltage in step 4 and the harmonic space voltage reference value in step 6 to obtain the reference voltage components of the ABC winding and the DEF winding in the stationary coordinate; Step 8: The ABC winding reference voltage component obtains a corresponding power device drive signal through the first pulse width modulation module (10), and the DEF winding reference voltage component obtains a corresponding power device drive signal through the second pulse width modulation module (11); the two sets of drive signals are respectively sent to the first three-phase inverter (15) and the second three-phase inverter (16) to jointly drive the dual three-phase motor (17).

3. A dual three-phase motor control system for single-phase open circuit fault according to claim 2, characterized in that: The harmonic space current reference value generating module (6) outputs a harmonic space current reference value which is determined by the torque space current reference value, the current amplitude ratio of the two sets of three-phase windings, and the current phase offset of the two sets of three-phase windings, and is expressed by the following formula: Among them, i z1_ref and i z2_ref are the current reference values ​​of the harmonic space z1 axis and z2 axis respectively; i d_ref and i q_ref are the current reference values ​​of the d-axis and q-axis in the torque space respectively; k and θ shift They are respectively the current amplitude ratio of the two sets of three-phase windings and the current phase offset of the two sets of three-phase windings.

4. A dual three-phase motor control system for single-phase open circuit fault according to claim 3, characterized in that: The harmonic space current control module (7) comprises a first adder, a second adder, a first notch filter, a second notch filter, a first PI controller, and a second PI controller; The positive input end of the first adder is connected to the harmonic space z1 axis current reference value, and the negative input end thereof is connected to the harmonic space z1 axis current actual value, and the output end of the first adder is connected to the input end of the first notch filter; the output end of the first notch filter is connected to the input end of the first PI controller, and the output end of the first PI controller is the harmonic space z1 axis reference voltage; The positive input end of the second adder is connected to the harmonic space z2 axis current reference value, and the reverse input end is connected to the harmonic space z2 axis current actual value, the output end of the second adder is connected to the input end of the second notch filter, the output end of the second notch filter is connected to the input end of the second PI controller, and the output end of the second PI controller is the harmonic space z2 axis reference voltage.

5. A dual three-phase motor control system for single-phase open circuit fault according to claim 4, characterized in that: In order to filter out the AC component of a specific frequency under a fault condition, the trap in the harmonic space current control module (7) has a center frequency of twice the fundamental electrical frequency. The trap G(s) of the harmonic space current control module (7) is expressed as: Where s is the Laplace operator, ω c is the center frequency of the notch filter, ξ is the damping ratio of the notch filter; the center frequency of the notch filter should be set to twice the fundamental electrical frequency ω c =2ω e =2n p ω n , n p is the number of motor pole pairs, ω n is the actual speed value.

6. A dual three-phase motor control system for single-phase open circuit fault according to claim 5, characterized in that: The anti-interference module (4) is characterized in that the torque space compensation voltage is calculated by using the actual value of the torque space current and the torque space reference voltage, thereby increasing the anti-interference performance of the torque space under fault conditions. Considering the simplicity of implementation, only the actual value of the torque space current is used to obtain the torque space compensation voltage, and the formula is as follows: u comp_dq =-(R active -R s )i dq Among them, u comp_dq and i dq are the torque space compensation voltage and the actual value of torque space current, R s is the torque space stator resistance, R active It is the torque space active resistor. Increasing its value will increase the torque space anti-interference ability.

7. A dual three-phase motor control system for single-phase open circuit fault according to claim 6, characterized in that: The control system and working method are applicable to healthy working conditions and fault working conditions, and can automatically switch between the two seamlessly without the need for fault identification and location diagnosis operations.

8. A dual three-phase motor control system for single-phase open circuit fault according to claim 7, characterized in that: The control system and working method achieve different optimization goals after a dual three-phase motor (17) system failure by adjusting the current amplitude ratio and phase offset of two sets of three-phase windings.

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