Research On Fauit Tolerant Control Of Five-phase PMSM Based On Finite Control Set Model Prediction Current Control

Five-phase permanent magnet synchronous motor(PMSM)has the advantages of high torque density,high efficiency,and low torque ripple.It has been widely used in electric vehicles,aviation,and ship propulsion in recent years.However,various faults may occur during the operation of the motor.The most common faults are phase open-circuit and short-circuit faults.If certain fault-tolerance strategies are not adopted,large torque ripples will occur,and even the motor will be damaged in severe cases.Therefore,this paper takes five-phase PMSM as an example,and proposes a simplified finite control set model predictive fault-tolerant control(FCS-MPFTC),so that the motor can maintain stable operation in the event of an open-circuit fault.On this basis,the short-circuit compensation current is injected to realize the fault-tolerant control of short-circuit faults.The main research content of this paper is as follows:(1)Establish the mathematical model of five-phase PMSM under normal,single-phase and two-phase open-circuit fault conditions.And deduce the decoupling transformation matrix and fault-tolerant current under single-phase and two-phase fault conditions.(2)Deduce the spatial distribution of the basic voltage vector of the five-phase voltage source inverter(VSI)under normal,single-phase and two-phase faults,and the virtual voltage vector synthesized by suppressing the third harmonic to zero(virtual voltage vector,V3)spatial distribution.On this basis,it focuses on analyzing the traditional FCS-MPFTC’s prediction model,cost function,and delay compensation principle when it fails,and verifies the effectiveness of the traditional fault-tolerant control strategy through simulation.(3)In order to solve the problems of high current harmonic content and large calculation amount in traditional FCS-MPFTC,a simplified FCS-MPFTC strategy is proposed.Based on the discrete mathematical model and the deadbeat principle,the current value function is equivalently transformed into a voltage value function,and the reference voltage vector is calculated according to the deadbeat.Sectors are re-divided for V3,so that the corresponding voltage vector in each sector is the optimal voltage vector,and the duty cycle of the voltage vector is calculated by combining the triangular relationship to realize open-circuit fault-tolerant operation.In addition,for short-circuit faults,a fault-tolerant control strategy that injects short-circuit compensation current into the reference current is proposed to realize fault-tolerant control of open-circuit and short-circuit faults.Finally,a simulation is built to verify the feasibility of the proposed control strategy.(4)A five-phase PMSM experimental platform based on the TMS320F2812 controller was built,and the traditional FCS-MPFTC,simplified FCS-MPFTC and short-cicuit fault-tolerant control strategy experiments were carried out,and the steady-state performance of the proposed control strategy and the traditional control strategy were comprehensively compared and analyzed.Dynamic performance,the results show that the proposed control strategy can effectively reduce the current harmonic content,calculation time,and torque ripple after a fault;at the same time,it can maintain good dynamic performance.The fault-tolerant control experiment is carried out under the short-circuit fault,and the feasibility of the proposed short-circuit current compensation strategy is verified.