A sensorless control method for dual three-phase permanent magnet synchronous motor suitable for single-phase open-circuit fault

Abstract

The application discloses a kind of dual three-phase permanent magnet synchronous motor sensorless control methods suitable for single-phase open-circuit fault, first, the virtual health model of dual three-phase permanent magnet synchronous motor after single-phase open-circuit fault is established, and the voltage constraint equation is deduced.On this basis, the voltage observer based on deadbeat predictive control is designed, the generated compensation voltage is injected into harmonic subspace in feedforward mode, to correct the input voltage signal distortion in back electromotive force observer.Finally, the rotor position and speed information is extracted from back electromotive force using limited position set phase-locked loop.The application overcomes the limitations of traditional sensorless method, not only maintains high-precision position estimation in healthy state, but also effectively reduces position estimation error and suppresses torque fluctuation when single-phase open-circuit fault occurs, especially suitable for dual three-phase permanent magnet synchronous motor sensorless drive system with strict requirements on reliability.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology and relates to a sensorless fault-tolerant method for open-circuit faults, specifically a sensorless control method for dual three-phase permanent magnet synchronous motors for single-phase open-circuit faults. Background Technology

[0002] Existing sensorless fault-tolerant methods applicable to open-circuit faults are mainly divided into two categories: The first category reconstructs the back EMF observation results in two subspaces to extract the back EMF component containing accurate rotor position information under open-circuit conditions; the second category analyzes the harmonic components of the back EMF introduced by the open-circuit fault and filters out these harmonics based on the notch filter principle, thereby ensuring the accuracy of rotor position estimation.

[0003] However, the aforementioned methods primarily focus on improving the accuracy of position calculation under open-circuit faults, while their effectiveness in improving system performance issues such as torque fluctuations caused by the fault is relatively limited. Therefore, the overall performance of existing sensorless control methods still falls short of the requirements for high-reliability applications, necessitating the development of more effective sensorless control strategies applicable to fault conditions to overcome current technological bottlenecks. Summary of the Invention

[0004] This invention provides a sensorless control method for dual three-phase permanent magnet synchronous motors with single-phase open-circuit faults. This method addresses the problem of decreased rotor position observation accuracy caused by single-phase open-circuit faults by proposing a feedforward compensation control strategy, which not only improves the accuracy of rotor position estimation but also effectively suppresses torque fluctuations.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A sensorless control method for a dual three-phase permanent magnet synchronous motor with single-phase open-circuit faults includes the following steps:

[0007] Step (1) Collect the six-phase current of the dual three-phase permanent magnet synchronous motor and locate the faulty phase based on this to determine the fault phase angle. :

[0008]

[0009] Step (2) involves performing a vector decoupling transformation on the phase current results to obtain the current values ​​in the torque subspace and harmonic subspace, respectively.

[0010] Step (3) For an open-circuit fault in phase A of the inverter, the discretized voltage constraint relationship is derived:

[0011]

[0012] In the formula, and These are the resistance and leakage inductance of the permanent magnet synchronous motor, respectively. and These represent the fault conditions of phase A, respectively. The shaft's compensation voltage and current, Representing the Current value at each cycle point For switching cycles;

[0013] Step (4) Based on the deadbeat model predictive control principle, in order to ensure that the estimated current can accurately follow the actual current, the required estimated compensation voltage is derived as follows:

[0014]

[0015] In the formula, and These represent the first phase under phase A fault conditions. Each cycle Estimated compensation voltage and estimated current for the shaft;

[0016] Step (5) According to the voltage constraint relationship, the estimated current at the next moment is determined by the estimated compensation voltage and the estimated current at the current moment:

[0017]

[0018] In the formula, Represents the first phase under fault conditions of phase A. Each cycle Estimated current of the shaft;

[0019] Step (6) Based on the estimated compensation voltage obtained under phase A fault, combined with the fault phase location information ,get shaft and The actual compensation voltage corresponding to the shaft:

[0020]

[0021] In the formula, and Represent shaft and The actual compensation voltage of the shaft, and These represent the fault conditions of phase A, respectively. shaft and Shaft compensation voltage;

[0022] Step (7) feeds the observed compensation voltage forward to the harmonic subspace and uses the model coupling characteristics under fault conditions to eliminate the transmission error between the controller reference voltage and the actual voltage.

[0023] Step (8) Collect the DC bus voltage of the inverter, Command voltage of shaft current regulator and The current information of the shaft, using The command voltage of the shaft current regulator and the DC bus voltage of the inverter are calculated separately. Command voltage for the shaft;

[0024] Step (9) will The command voltage and current signals of the shaft are used as inputs to the back EMF observer. The back EMF observer is constructed, and the observed back EMF results are input to the finite position phase-locked loop to finally calculate the rotor position and speed information.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. This invention incorporates post-fault voltage constraints and designs a compensated voltage observer based on deadbeat predictive control theory. This observer not only accurately estimates the compensated voltage but also improves dynamic response performance without introducing additional parameters.

[0027] 2. This invention feeds the observed compensation voltage forward to the harmonic subspace, effectively suppressing the voltage distortion caused by single-phase open-circuit faults, thereby eliminating the impact of faults on rotor position estimation from the root.

[0028] 3. This invention utilizes the coupling relationship between subspaces after a fault and compensates for the command voltage of the harmonic subspace, thereby effectively improving the torque fluctuation problem of the system.

[0029] 4. This invention overcomes the limitations of traditional sensorless methods. It not only maintains high-precision position estimation under healthy conditions, but also effectively reduces position estimation errors and suppresses torque fluctuations when a single-phase open-circuit fault occurs. It is particularly suitable for sensorless drive systems of dual three-phase permanent magnet synchronous motors with stringent reliability requirements. Attached Figure Description

[0030] Figure 1 This is a block diagram of a voltage observer based on deadbeat predictive control.

[0031] Figure 2 A comparison of position error waveforms under rated load using traditional methods and the method proposed in this invention;

[0032] Figure 3This is a comparison of the current waveforms under rated load using the conventional method and the method proposed in this invention. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0034] This invention provides a sensorless control method for a dual-phase three-phase permanent magnet synchronous motor (PMSM) with a single-phase open-circuit fault. First, a virtual health model of the PMSM after a single-phase open-circuit fault is established, and its voltage constraint equation is derived. Based on this, a voltage observer based on deadbeat predictive control is designed, and the generated compensation voltage is injected into the harmonic subspace via a feedforward method to correct the distortion of the input voltage signal in the back EMF observer. Finally, a finite-position phase-locked loop (PLL) is used to extract rotor position and speed information from the back EMF. The specific steps are as follows:

[0035] (1) Collect the six-phase current of the dual three-phase permanent magnet synchronous motor and locate the faulty phase based on this to determine the fault phase angle. .

[0036]

[0037] (2) By performing vector decoupling transformation on the phase current results, the current values ​​in the torque subspace and harmonic subspace are obtained respectively.

[0038] (3) Taking the open-circuit fault of phase A of the inverter as an example, the voltage constraint relationship after discretization is derived:

[0039]

[0040] In the formula, and These are the resistance and leakage inductance of the permanent magnet synchronous motor, respectively. and These represent the fault conditions of phase A, respectively. The shaft's compensation voltage and current, Representing the Current value at each cycle point The switching cycle.

[0041] (4) Based on the deadbeat model predictive control principle, in order for the estimated current to accurately follow the actual current, the required estimated compensation voltage can be derived as follows:

[0042]

[0043] In the formula, and These represent the first phase under phase A fault conditions. Each cycle The estimated compensation voltage and estimated current of the shaft.

[0044] (5) According to the voltage constraint relationship, the estimated current at the next moment can be determined by the estimated compensation voltage and the estimated current at the current moment.

[0045]

[0046] (6) Figure 1 This invention demonstrates the voltage observer based on deadbeat predictive control in [the following context is missing from the original text] Block diagram of the control structure on the axis. Based on the estimated compensation voltage obtained under phase A fault, combined with the fault phase location information. This can be extended to other fault conditions, thereby obtaining shaft and The actual compensation voltage corresponding to the axis.

[0047]

[0048] In the formula, and Represent shaft and The actual compensation voltage of the shaft.

[0049] (7) By feeding the observed compensation voltage forward to the harmonic subspace, the transmission error between the controller reference voltage and the actual voltage can be eliminated by taking advantage of the model coupling characteristics under fault conditions.

[0050] (8) Collect the DC bus voltage of the inverter, Command voltage of shaft current regulator and Current information of the shaft. Utilizing The command voltage of the shaft current regulator and the DC bus voltage of the inverter are calculated. Command voltage for the axis.

[0051] (9) The command voltage and current signals of the shaft are used as inputs to construct a back EMF observer. The observed back EMF results are then input into a finite position phase-locked loop (PLL) to finally calculate the rotor position and speed information.

[0052] Steps (3), (4), (5), (6) and (7) together constitute the voltage observer based on deadbeat predictive control proposed in this invention. This observer is the core component of this invention to achieve high-precision position estimation under fault conditions.

[0053] This invention can effectively suppress rotor position estimation errors under single-phase open-circuit fault conditions. To verify the technical effect of this invention, comparative experiments were conducted under rated load conditions using both conventional and traditional methods. The results are as follows: Figure 2 and Figure 3 As shown.

[0054] Figure 2 The rotor position estimation error waveforms under the two methods were compared. After adopting the method of the present invention, the harmonic distortion of the rotor position estimation waveform was significantly reduced, the estimation error amplitude decreased from 14.3° to 5.5°, and the accuracy was improved by 61.5%.

[0055] Figure 3 The current response waveforms under the two methods were compared, from top to bottom: phase current, ... shaft current and Shaft current. Since the prototype used in this invention is a surface-mounted permanent magnet synchronous motor, its electromagnetic torque is... The current is proportional to the shaft current. Figure 3 It is evident that although both methods can achieve sensorless speed closed-loop control, the method of this invention... The smaller shaft current fluctuation indicates that it can effectively suppress torque fluctuation, further verifying the superiority of the method of the present invention.

Claims

1. A sensorless control method for a dual three-phase permanent magnet synchronous motor with single-phase open-circuit fault, characterized in that... The method includes the following steps: Step (1) Collect the six-phase current of the dual three-phase permanent magnet synchronous motor and locate the faulty phase based on this to determine the fault phase angle. ; Step (2) involves performing a vector decoupling transformation on the phase current results to obtain the current values ​​in the torque subspace and harmonic subspace, respectively. Step (3) For the open circuit fault of phase A of the inverter, the voltage constraint relationship after discretization is derived; Step (4) Based on the predictive control principle of the deadbeat model, in order to make the estimated current accurately follow the actual current, derive the required estimated compensation voltage; Step (5) According to the voltage constraint relationship, the estimated current at the next moment is determined by the estimated compensation voltage and the estimated current at the current moment. Step (6) Based on the estimated compensation voltage obtained under phase A fault, combined with the fault phase location information ,get shaft and The actual compensation voltage corresponding to the axis; Step (7) feeds the observed compensation voltage forward to the harmonic subspace and uses the model coupling characteristics under fault conditions to eliminate the transmission error between the controller reference voltage and the actual voltage. Step (8) Collect the DC bus voltage of the inverter, Command voltage of shaft current regulator and The current information of the shaft, using The command voltage of the shaft current regulator and the DC bus voltage of the inverter are calculated separately. Command voltage for the shaft; Step (9) will The command voltage and current signals of the shaft are used as inputs to the back EMF observer. The back EMF observer is constructed, and the observed back EMF results are input to the finite position phase-locked loop to finally calculate the rotor position and speed information.

2. The sensorless control method for a dual three-phase permanent magnet synchronous motor with a single-phase open-circuit fault according to claim 1, characterized in that... The fault phase angle Represented as: 。 3. The sensorless control method for a dual three-phase permanent magnet synchronous motor with a single-phase open-circuit fault according to claim 1, characterized in that... The voltage constraint relationship after discretization is expressed as follows: In the formula, and These are the resistance and leakage inductance of the permanent magnet synchronous motor, respectively. and These represent the fault conditions of phase A, respectively. The shaft's compensation voltage and current, Representing the Current value at each cycle point The switching cycle.

4. The sensorless control method for a dual three-phase permanent magnet synchronous motor with a single-phase open-circuit fault according to claim 1, characterized in that... The estimated compensation voltage is expressed as: In the formula, and These represent the first phase under fault conditions A. Each cycle The estimated compensation voltage and estimated current of the shaft. and These are the resistance and leakage inductance of the permanent magnet synchronous motor, respectively. Representing the Current value at each cycle point The switching cycle.

5. The sensorless control method for a dual three-phase permanent magnet synchronous motor with a single-phase open-circuit fault according to claim 1, characterized in that... The estimated current is expressed as: In the formula, Represents the first phase under fault conditions of phase A. Each cycle Estimated current of the shaft, and These are the resistance and leakage inductance of the permanent magnet synchronous motor, respectively. and These represent the first phase under fault conditions A. Each cycle The estimated compensation voltage and estimated current of the shaft. The switching cycle.

6. The sensorless control method for a dual three-phase permanent magnet synchronous motor with a single-phase open-circuit fault according to claim 1, characterized in that... The shaft and The actual compensation voltage corresponding to the shaft is expressed as: In the formula, and Represent shaft and The actual compensation voltage of the shaft, and These represent the fault conditions of phase A, respectively. shaft and Compensation voltage for the shaft.

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