Third harmonic injection fault-tolerant control algorithm for dual three-phase permanent magnet synchronous motor under one-phase open-circuit fault

Abstract

The present invention relates to the technical field of multi-phase motor control. Disclosed is a third harmonic injection fault-tolerant control algorithm for a dual three-phase permanent magnet synchronous motor under a one-phase open-circuit fault. In order to improve the torque output capability after open-circuit fault fault-tolerant operation of the dual three-phase motor, disclosed in the present invention is a phase-loss reduced-order fault-tolerant control strategy of the dual three-phase motor. The implementation of the method mainly comprises: 1. when a phase-loss fault occurs, connecting neutral points of two sets of three-phase windings to the midpoint of a bus capacitor; 2, constructing a new reduced-order fault-tolerant matrix; and 3, injecting third harmonics by means of a rotating synchronous coordinate system. According to the new reduced-order fault-tolerant matrix provided by the present invention, the fault-tolerant control strategy is operated, so that the utilization rate of a motor iron core can be increased, a fault-tolerant phase current peak value and winding copper loss are reduced, and the reliability of the motor during fault-tolerant operation is improved.

Description

A third harmonic injection fault-tolerant control algorithm for dual three-phase permanent magnet synchronous motors with one-phase open-circuit fault Technical Field

[0001] The present invention belongs to the field of multi-phase motor drive control, and in particular relates to a harmonic injection fault-tolerant control method for a dual three-phase permanent magnet synchronous motor containing a third harmonic back electromotive force. Background Art

[0002] Dual three-phase permanent magnet synchronous motors (PMSMs) offer advantages such as high efficiency, high power density, low torque ripple, and strong fault tolerance. They have attracted widespread attention and application in aerospace, electric vehicles, and ship propulsion systems. Compared to three-phase motors, their doubled number of windings significantly improves system reliability. Open-circuit faults are a common type of fault in motor operation, typically caused by factors such as broken semiconductor wafer bond wires, connector detachment, and overcurrent fuses. For dual three-phase motors, appropriate fault tolerance strategies can be implemented to maintain a circular air gap magnetic field during open-circuit faults, allowing the motor to continue operating with minimal torque ripple. However, fault-tolerant operation inevitably increases the peak phase current of the motor, potentially causing the motor windings and power semiconductors to operate outside their designed rated conditions. This results in significant current stress on the entire system, impacting system reliability. In severe cases, the fault tolerance algorithm will derating the motor output, limiting output power.

[0003] In some high-torque applications, the motor's back EMF waveform is designed to be non-sinusoidal to increase torque density. Appropriately injecting low-order harmonic currents can improve the motor's core utilization, reduce current peaks, and increase torque output. Therefore, in the event of a motor phase loss, harmonic injection into a dual three-phase motor with non-sinusoidal back EMF can reduce the phase current peaks after fault tolerance, improving system output capacity and reliability.

[0004] The traditional dual three-phase motor one-phase open circuit reduced-order fault-tolerant strategy usually selects different reduced-order matrix transformations for control according to the connection conditions of the motor windings. For dual three-phase permanent magnet synchronous motors containing third harmonic back EMF, a circuit that isolates the neutral points of the two sets of three-phase windings is usually selected to suppress the third harmonic. The reduced-order fault-tolerant matrix derived based on this cannot well meet the needs of third harmonic injection. It is urgent to propose a harmonic injection fault-tolerant control method for dual three-phase permanent magnet synchronous motors containing third harmonic back EMF to improve the reliability of the motor system. Therefore, constructing a new reduced-order fault-tolerant matrix for dual three-phase permanent magnet synchronous motors and using this matrix to perform third harmonic current injection control after fault tolerance is the focus of the present invention.

[0005] Summary of the Invention

[0006] The purpose of the invention is to achieve third harmonic injection in the event of a single-phase open-circuit fault in a dual three-phase permanent magnet synchronous motor containing a third harmonic back EMF, thereby improving the torque output capability and system reliability under fault conditions. The present invention discloses a single-phase open-circuit reduced-order fault-tolerant control technology for a dual three-phase permanent magnet synchronous motor containing a third harmonic back EMF.

[0007] Technical solution: To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a third harmonic injection control algorithm for a dual three-phase permanent magnet synchronous motor containing a third harmonic back electromotive force when one phase is open-circuited. The implementation steps include: step 1), connecting the neutral point of the winding to the midpoint of the bus capacitor of the inverter, and collecting the control quantity required for the operation of the motor. The speed closed loop automatically outputs the required torque size, and the torque is distributed to the fundamental torque given and the harmonic torque given according to a certain ratio. Step 2) The fundamental component and the zero-sequence component are extracted through the proposed reduced-order matrix, and combined with the output of the speed loop to form a fundamental and zero-sequence current controller, thereby realizing dual closed-loop control of the harmonic torque and the fundamental torque. Step 3) The required duty cycle is output through the inverse transformation of the reduced-order matrix and output to the voltage source inverter.

[0009] Furthermore, the specific process of step 1) is as follows:

[0010] Step 1.1) As shown in Figure 2, when an open circuit fault occurs in phase F of the motor, the neutral points of the two windings of the dual three-phase motor are connected to the midpoint of the bus capacitor of the dual three-phase inverter, that is, the neutral point voltage is clamped to Udc / 2 (Udc is the bus voltage). Use a current sensor to collect the phase current [i A i B i C i D i E ] T , use the position sensor to collect the position information θ and motor speed ω.

[0011] Step 1.2) The error signal between the collected ω and the given speed ω* is transmitted to the PI controller, and the PI controller outputs a q-axis reference given quantity related to the torque. In the present invention, the q-axis given quantity will be distributed according to a certain ratio k psi For the controller of fundamental wave and zero sequence space, the required torque is synthesized by the fundamental wave q axis current and the zero sequence space q axis current. The specific proportional relationship is as follows

[0012] Further, the specific process of step 2) is:

[0013] Step 2.1) According to the dual three-phase space coordinate decoupling theory, the F-phase missing reduced-order fault-tolerant matrix of the dual three-phase permanent magnet synchronous motor is reconstructed. The proposed new reduced-order fault-tolerant matrix T clarke_new as follows:

[0014] The double three-phase motor with missing F phase and containing the third magnetomotive force component can be reduced by the matrix T clarke_new Transform the variables in the natural coordinate system to the αβ plane, the z1 axis, and the o1o2 zero-sequence plane. Subsequently, the variables in the two-phase stationary coordinate system are mapped to the synchronous rotating coordinate system via Park transformation. At this time, the zero-sequence spatial component participates in the energy conversion, so the αβ plane components and the o1o2 zero-sequence components need to be rotated simultaneously. The Park transformation matrix at this time can be expressed as:

[0015] Where θe is the electrical angle. clarke_new With T park By multiplying them together, we can get the transformation matrix T from the natural coordinate system to the synchronously rotating coordinate system. T = T park T clarke_new

[0016] Therefore, the relationship between the rotation coordinate system and the natural coordinate system of the proposed reduced-order fault-tolerance strategy can be expressed as follows: [f d f q f z1 f o1 f o2 ] T =T[f A f B f C f D f E ] T

[0017] where f d ,f q ,f z1 ,f o1 ,f o2 Respectively represent the size of the variable projected on the d-axis, q-axis, z1-axis, o1-axis, and o2-axis; f A ,f B ,f C ,f D ,f E They represent the component sizes of phase A, phase B, phase C, phase D, and phase E in the natural coordinate system respectively.

[0018] Step 2.2) Using the transformation matrix in Step 2.1, we can derive the voltage equation for the synchronously rotating coordinate system. The following equation shows the voltage expression for the synchronously rotating axis system in the αβ plane and the o1o2 zero-sequence plane. The dq plane is derived by rotating the αβ plane, and the d3-q3 plane is derived by rotating the o1o2 zero-sequence plane. Due to the presence of the third-harmonic magnetomotive force, both planes participate in the synthesis of torque. Therefore, in a two-dimensional rotating synchronous coordinate system at different speeds, the dq axis system and the d3-q3 axis system have the same physical meaning: the d-axis or d3-axis represents the magnitude of the excitation, and the q-axis or q3 represents the magnitude of the electromagnetic torque (there is no saliency effect in either the fundamental or harmonic space).

[0019] Among them, R s is the phase resistance, i o1 is the zero-sequence space o1 axis current, i o2 is the zero-sequence space o2 axis current, L d3 is the d3-axis inductance, L q3 is the inductance of axis q3, ψ f1 is the fundamental flux of the permanent magnet, ψ f3 is the third harmonic flux linkage of the permanent magnet, ω e is the electrical angular velocity, and t is the time.

[0020] The following equation shows the voltage equation for the z1 axis. The projection of the magnetomotive force of any order on this axis is 0, so it does not participate in the electromechanical energy conversion. The voltage on this axis only produces harmonic currents:

[0021] Among them, L z1 is the z1-axis inductance.

[0022] Considering only the fundamental wave and the third harmonic, the permanent magnet flux linkage ψ of the dual three-phase motor under the condition of open circuit of phase F is f The expression is given by:

[0023] Substitute the phase current and flux into the magnetic common energy derivative formula:

[0024] Where p is the number of motor pole pairs, I s is the column vector of motor phase current, L s is the column vector of phase self-inductance, W co Represents magnetic energy.

[0025] Through the transformation T proposed in step 2.1), the current expression under each harmonic plane is used, and the torque expression under the reduced-order fault-tolerant matrix is ​​finally obtained:

[0026] If the currents of the d-axis, z1-axis, and d3-axis are all controlled to 0, the torque expression of the strategy proposed in this invention can be theoretically obtained as follows:

[0027] Further, the specific process described in step 3) is:

[0028] Step 3.1) The currents of each synchronous rotating axis system obtained by the transformation in step 2.2) are then subtracted from the currents of each axis after the transformation according to the q-axis and q3-axis given in step 1.2) and input into the PI controller. The controller will output the current position and the required u under the current according to the transfer function under the set discrete model. d ,u q ,u z1 ,u d3 ,u q3 This will form a complete current inner loop, as shown in Figure 3.

[0029] Step 3.2) Reduce the decoupling matrix T clarke_new The inverse transformation can be expressed as follows

[0030] By this matrix and the rotation transformation T park The inverse transform T park_inv , the components of the synchronous rotating axis system can be transformed into the natural coordinate system, that is, [u d ,u q ,u z1 ,u d3 ,u q3 ] T Transform to [u A ,u B ,u C ,u D ,u E ] T .

[0031] Step 3.3) The phase voltage [u A ,u B ,u C ,u D ,u E ] T, by performing carrier modulation with a triangle wave consistent with the switching frequency, the duty cycle required by the half-bridge arm in the control cycle can be obtained. Finally, the simulated current waveform obtained by control is shown in Figure 7. Compared with the fault-tolerant control algorithm under the traditional reduced-order matrix minimum copper loss constraint shown in Figure 6, the phase current peak is reduced. Figure 4 shows the torque pulsation of the traditional minimum copper loss reduced-order fault-tolerant method in the simulation, and Figure 5 shows the torque pulsation of the method proposed in the present invention in the simulation. By comparison, it can be found that the present method further reduces the phase current peak in the open circuit condition on the basis of no change in the torque pulsation, verifying the effectiveness of the algorithm proposed in the present invention.

[0032] Beneficial effects of the present invention:

[0033] 1) Based on the control strategy of reduced-order fault-tolerant control of one phase open circuit of dual three-phase motors under the constraint of minimum copper loss, the present invention proposes a reduced-order fault-tolerant transformation matrix for injecting third harmonic current. Under this transformation matrix, the subspaces are uncoupled from each other, the controls are independent of each other, and the control structure is simple.

[0034] 2) When one phase is open-circuited, the fault-tolerant control strategy is adopted for the dual three-phase motor containing the third harmonic back EMF, which can further reduce the motor copper loss based on the traditional minimum copper loss strategy that only considers the fundamental back EMF.

[0035] 3) When one phase is open-circuited, the fault-tolerant control strategy is adopted for a dual three-phase motor with third harmonic back EMF. This can reduce the peak current of each phase under the constraint of minimum copper loss, thereby reducing the current stress of the drive and improving reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a block diagram of a dual three-phase motor reduced-order fault-tolerant control system.

[0037] Figure 2 is a schematic diagram of the main circuit topology

[0038] Figure 3 is the proposed reduced-order decoupling harmonic current injection flow chart

[0039] Figure 4 shows the torque ripple simulation results of the traditional isolated neutral point minimum copper loss fault tolerance strategy

[0040] Figure 5 shows the torque ripple simulation results of the proposed minimum copper loss fault tolerance strategy

[0041] Figure 6 shows the phase current simulation results of the traditional isolated neutral point minimum copper loss fault tolerance strategy

[0042] Figure 7 shows the phase current simulation results of the proposed minimum copper loss fault tolerance strategy DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] As shown in the control block diagram of Figure 1, the present invention proposes a third harmonic injection control algorithm for a dual three-phase permanent magnet synchronous motor with a third harmonic back EMF when one phase is open-circuited. The specific implementation steps of the proposed fault-tolerant control method include:

[0045] Step 1) Connect the winding's neutral point to the midpoint of the inverter's busbar capacitor and collect the motor's required control variables, including current, speed, and position angle. The closed-loop speed controller outputs the required torque, which is then distributed proportionally between the fundamental and harmonic torques.

[0046] Step 1.1) As shown in Figure 1, when an open circuit fault occurs in phase F of the motor, the neutral points of the two windings of the dual three-phase motor are connected to the midpoint of the bus capacitor of the dual three-phase inverter, that is, the neutral point voltage is clamped to Udc / 2. Use a current sensor to collect the phase current [i A i B i C i D i E ] T , use a rotary transformer to collect position information θ and motor speed ω.

[0047] Step 1.2) The error signal between the collected ω and the given speed ω* is transmitted to the PI controller, and the PI controller outputs a q-axis reference given quantity related to the torque. In the present invention, the q-axis given quantity will be distributed according to a certain ratio k psi For the controller of fundamental wave and zero sequence space, the required torque is synthesized by the fundamental wave q axis current and the zero sequence space q axis current. The q axis current of each subspace is allocated according to the proportion of back electromotive force. The specific proportion relationship is shown in the following formula

[0048] Step 2) The fundamental components of the dq-axis current, the z1-axis current, and the zero-sequence space d3-q3-axis current after tripled fundamental frequency rotation are extracted using the proposed reduced-order matrix. The d-axis reference current, the z1-axis reference current, and the d3-axis reference current are set to 0, and the q-axis and q3-axis reference currents are the fundamental torque reference and harmonic torque reference, respectively, calculated in step 1.

[0049] Step 2.1) According to the present invention's requirement for controlling zero-sequence space torque, the reduced-order fault-tolerant matrix should prioritize the control degrees of freedom of the fundamental and zero-sequence spaces. Therefore, the proposed reduced-order decoupling matrix should be able to transform the variables d to the αβ plane, the o1o2 zero-sequence plane, and the z1 axis. According to the dual three-phase space vector decoupling theory, to achieve decoupling control, the variables decomposed from the natural coordinate system should satisfy orthogonal characteristics. Each axis of the matrix should satisfy the following constraints: β·α T =0 z1·α T =z1·β T =0

[0050] Among them, α, β, z1, o1, and o2 represent the corresponding row vectors in the Clarke matrix respectively.

[0051] The following formula is the VSD decoupling matrix derived from the winding distribution of a dual three-phase motor when the windings are in a healthy state. The first six columns represent the A to F phase windings, and the first six rows represent the projected axes αβ, z1z2, and o1o2, respectively.

[0052] Taking the open circuit of phase F as an example, the process of deriving the reduced-order matrix is ​​to delete the sixth column, then delete the z2 axis, set the last row of the matrix to five unknowns x1, x2, x3, x4, and x5, and use the orthogonal constraints to derive the following constraints:

[0053] Then x5 is 1, and the new reduced-order fault-tolerant matrix T after the dual three-phase permanent magnet synchronous motor is missing phase F is reconstructed. clarke_new as follows:

[0054] The reduced-order fault-tolerant matrix expands the degree of freedom of zero-sequence plane control while retaining the complete fundamental wave projection relationship, allowing the third harmonic to be injected.

[0055] When the dual three-phase motor with three-phase magnetomotive force component has a phase F fault, it can be solved by reducing the order matrix T clarke_new Transform the variables in the natural coordinate system to the αβ plane, the z1 axis, and the o1o2 zero-sequence plane. Subsequently, the variables in the two-phase stationary coordinate system are mapped to the synchronous rotating coordinate system via Park transformation. At this time, the zero-sequence spatial component participates in the energy conversion, so the αβ plane components and the o1o2 zero-sequence components need to be rotated simultaneously. The Park transformation matrix at this time can be expressed as:

[0056] Where θe is the electrical angle. clarke_new With T parkBy multiplying them together, we can get the transformation matrix T from the natural coordinate system to the synchronously rotating coordinate system. T = T park T clarke_new

[0057] Therefore, the relationship between the rotation coordinate system and the natural coordinate system of the proposed reduced-order fault-tolerance strategy can be expressed as follows: [f d f q f z1 f o1 f o2 ] T =T[f A f B f C f D f E ] T

[0058] Step 2.2) Using the transformation matrix in Step 2.1, we can derive the voltage equation in the synchronously rotating coordinate system. The voltage expressions for the αβ plane and the o1o2 zero-sequence plane are shown below. Due to the presence of the third-harmonic magnetomotive force, both planes contribute to the torque synthesis. Therefore, in a two-dimensional rotating synchronous coordinate system at different speeds, the dq axis system and the d3-q3 axis system have the same physical meaning: the d-axis or d3-axis represents the magnitude of the excitation, and the q-axis or q3 represents the magnitude of the electromagnetic torque (there is no saliency effect in either the fundamental or harmonic space).

[0059] The following equation shows the voltage equation for the z1 axis. The projection of the magnetomotive force of any order on this axis is 0, so it does not participate in the electromechanical energy conversion. The voltage on this axis only generates harmonic currents:

[0060] Since the back EMF of the motor is generated by the flux linkage, only the fundamental wave and the third harmonic are considered. The permanent magnet flux linkage expression of the dual three-phase motor under the condition of open circuit of phase F is given by the following formula:

[0061] Substitute the phase current and magnetic flux into the formula for the derivation of magnetic common energy.

[0062] And project the current onto the dq plane, z1 axis and d3q3 plane, and finally get the torque expression under the reduced-order fault-tolerant matrix.

[0063] By controlling the currents of the d-axis, z1-axis, and d3-axis to 0, the torque expression of the strategy proposed in the present invention can be obtained in theory.

[0064] Step 2.3) Based on the q-axis and q3-axis given in step 1, combined with the currents of each synchronous rotating axis system obtained by the transformation in step 2.2) and combined with the PI controller, a complete current inner loop can be formed. As shown in Figure 3, the current loop contains 5 PI controllers, which output u α ,u β ,u z1 ,u o1 ,u o2 . Where u α ,u β Represents the fundamental space α-axis β-axis voltage, u o1 ,u o2 They represent the zero-sequence space o1-axis and o2-axis voltages respectively.

[0065] Direct axis voltage and zero sequence space direct axis voltage; u q ,u q3 Represents the fundamental quadrature axis voltage and zero sequence space quadrature axis voltage respectively, u z1 ,u z2 They represent the voltages of the z1 and z2 axes respectively.

[0066] Step 3) Subtract the given current in step 2 from the current of each axis after transformation, and input it into the PI controller to obtain the output voltage u required for each space. d ,u q ,u z1 ,u d3 ,u q3 The required duty cycle of each phase is then output through the inverse transformation of the reduced-order matrix and output to the voltage source inverter to drive the dual three-phase motor.

[0067] Step 3.1) The currents of each synchronous rotating axis system obtained by the transformation in step 2.2) are then subtracted from the currents of each axis after the transformation according to the q-axis and q3-axis given in step 1.2) and input into the PI controller. The controller will output the current position and the required u under the current according to the transfer function under the set discrete model. d ,u q ,u z1 ,u d3 ,u q3 This will form a complete current inner loop, as shown in Figure 3.

[0068] Step 3.2) T clarke_inv is the reduced-order decoupling matrix T clarke_new The inverse transformation is obtained by using this matrix and the rotation transformation T park The inverse transform T park_inv , the components of the synchronous rotating axis system can be transformed into the natural coordinate system, that is, [u d ,u q ,uz1 ,u d3 ,u q3 ] T Transform to [u A ,u B ,u C ,u D ,u E ] T .

[0069] Step 3.3) The phase voltage [u A ,u B ,u C ,u D ,u E ] T , by performing carrier modulation with a triangle wave consistent with the switching frequency, the duty cycle required by the half-bridge arm in the control cycle can be obtained. Finally, the simulated current waveform obtained by control is shown in Figure 7. Compared with the fault-tolerant control algorithm under the traditional reduced-order matrix minimum copper loss constraint shown in Figure 6, the phase current peak is reduced. Figure 4 shows the torque pulsation of the traditional minimum copper loss reduced-order fault-tolerant method in the simulation, and Figure 5 shows the torque pulsation of the method proposed in the present invention in the simulation. By comparison, it can be found that the present method further reduces the phase current peak in the open circuit condition on the basis of no change in the torque pulsation, verifying the effectiveness of the algorithm proposed in the present invention.

[0070] The above embodiments are intended only to illustrate the design concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly, thereby obtaining a fault-tolerant control method for single-phase fault reconstruction of an open-winding dual three-phase permanent magnet synchronous motor. Therefore, any equivalent changes or modifications based on the principles and design concepts disclosed in this invention are intended to be within the scope of protection of this invention.

Claims

1. A third harmonic injection control method for a dual three-phase permanent magnet synchronous motor containing a third harmonic back electromotive force when one phase is open circuit fault, characterized in that The following steps are involved: Step 1) Connect the neutral point of the winding to the midpoint of the bus capacitor of the inverter, and collect the control variables such as the current, speed and position angle required for the operation of the motor; the speed closed loop outputs the required torque through the PI controller, and the torque is allocated to the fundamental torque setting and the harmonic torque setting according to a certain ratio; Step 2) Create a new open circuit reduced-order fault-tolerant matrix, transform each phase current into five orthogonal axis systems, namely dq, d3-q3 and z1, and use a PI controller for control; The d-axis reference current, z1-axis reference current and d3-axis reference current are set to 0, and the q-axis and q3-axis reference currents are the fundamental torque reference and harmonic torque reference calculated in step 1) respectively; Step 3) Each axis controller obtains the voltage u required to be output in each space d ,u q ,u z1 ,u d3 ,u q3 , and then output the required duty cycle of each phase through the inverse transformation of the reduced-order matrix, and output it to the voltage source inverter to drive the dual three-phase motor to operate. d ,u d3 Represent the fundamental direct-axis voltage and zero-sequence space direct-axis voltage respectively; u q ,u q3 Represents the fundamental quadrature voltage and zero-sequence space quadrature voltage, u z1 ,u z2 They represent the voltages of the z1 axis and the z2 axis respectively.

2. The method according to claim 1, characterized in that: The step 1 specifically comprises the following steps: Step 1.1) When an open-circuit fault occurs in the motor F phase, the neutral points of the two sets of windings of the dual three-phase motor are connected to the midpoint of the bus capacitor of the dual three-phase inverter, that is, the neutral point voltage is clamped to Udc / 2, where Udc is the bus voltage; the phase current [i A i B i C i D i E ] T , use a rotary transformer to collect position information θ and motor speed ω; Step 1.2) The error signal between the collected ω and the given speed ω* is transmitted to the PI controller, and the PI controller outputs the q-axis reference given quantity related to the torque. The q-axis reference given quantity will be distributed to k according to a certain proportion. psi For the controller of fundamental wave and zero sequence space; the required torque is synthesized by the fundamental wave q-axis current and the zero sequence space q-axis current; the specific proportional relationship is as follows Among them, E1 and E3 represent the fundamental back EMF amplitude and the third harmonic back EMF amplitude of the motor respectively. q ,i q3 Represent the fundamental quadrature current and zero-sequence space quadrature current, ψ f1 ,ψ f3 Represent the fundamental flux and harmonic flux amplitudes respectively, k psi Stands for harmonic current injection ratio.

3. The method according to claim 1, characterized in that The step 2 specifically includes the following steps: Step 2.1) According to the dual three-phase space vector decoupling theory (i.e., VSD theory), the dual three-phase permanent magnet synchronous motor missing F-phase reduced-order fault-tolerant matrix is ​​reconstructed. The proposed new reduced-order fault-tolerant matrix T clarke_new as follows: The double three-phase motor with missing F phase and containing the third magnetomotive force component can be reduced by the matrix T clarke_new Transform each variable in the natural coordinate system to the αβ plane, z1 axis and o1o2 zero-sequence plane; The variables in the two-phase stationary coordinate system are mapped to the synchronous rotating coordinate system through Park transformation; the Park transformation matrix at this time can be expressed as: Where θe is the electrical angle; T clarke_new With T park Multiply them together to obtain the transformation matrix T from the natural coordinate system to the synchronously rotating coordinate system; T=T park T clarke_new Step 2.2) Project the five-phase current components in the natural coordinate system onto the dq plane, z1 axis and d3-q3 plane through the created transformation matrix to obtain [i d ,i q ,i z1 ,i d3 ,i q3 ] T ; where i d ,i d3 Represents the fundamental direct-axis current and zero-sequence space direct-axis current, i z1 Represents the current magnitude of the z1 axis.

4. The method according to claim 1, characterized in that: The specific steps of step 3) include: Step 3.1) Subtract the current of each synchronous rotating shaft system obtained by transformation from the given current and input it into the PI controller to obtain the voltage u required to be output in each space. d ,u q ,u z1 ,u d3 ,u q3 , thus forming a complete inner current loop; Step 3.2) T clarke_inv is the reduced-order decoupling matrix T clarke_new The inverse transformation is achieved by using this matrix and the reverse rotation transformation T park_inv , the components of the synchronous rotating axis system can be transformed into the natural coordinate system, that is, [u d ,u q ,u z1 ,u d3 ,u q3 ] T Transform to [u A ,u B ,u C ,u D ,u E ] T ; where u A ,u B ,u C ,u D ,u E They represent the five-phase voltages of A, B, C, D, and E respectively. Step 3.3) According to the calculated phase voltage [u A ,u B ,u C ,u D ,u E ] T By modulating the carrier with a triangular wave consistent with the switching frequency, the duty cycle required by the half-bridge arm in the control cycle can be obtained; and then the duty cycle is output to the upper and lower bridge arms of the dual three-phase inverter, thereby driving the motor to rotate.

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