Research On Multi-operation Mode Dual Five-phase Hybrid Excitation Permanent Magnet Motor Control System

Multi-operation Mode Dual Five-phase Hybrid Excitation Permanent Magnet Motor(MOM-DFHEPM)combines the advantages of dual-stator permanent magnet motor,hybrid excitation motor and multi-phase permanent magnet motor.The MOM-DFHEPM has four operation modes: main drive/auxiliary drive winding working alone,main drive/auxiliary drive winding working simultaneously,and hybrid excitation with auxiliary drive winding excitation,which has broad application prospects in electric vehicles,electric ships and electric aircraft.However,the existing control strategies only focus on the high performance operation of single five-phase motors or hybrid excitation motors,ignoring the efficiency differences of the four operating modes at different speeds and torque zones,making it difficult to realize the wide range of efficient operation of this new motor system.This paper fully explores the operating characteristics of this new permanent magnet motor,deduces the mathematical model of the rotating coordinate system under four operating modes,and then proposes the optimal torque distribution control under the constraint of minimum copper consumption to realize the optimal torque distribution of the motor under four different operating modes,reduce the copper consumption during operation,and improve the efficiency of the motor under four operating modes.At the same time,the high-efficiency operation zones of the motor in the four operation modes are differentitated,and the principles for selecting the operation modes under the wide range of high-efficiency requirements are formed.In addition,to address the problem that the PI regulator is prone to saturation and system instability when the motor is running at high speed by the voltage feedback weak-magnetization method,a new weak-magnetization control method is proposed in this paper,in which the flux weakening correction current is directly given by the real-time motor speed and torque,which effectively improves the steady-state performance of the motor system.Considering the regulating effect of the auxiliary drive stator excitation winding on the main drive air gap magnetic field,the motor operating speed domain is further widened by using the auxiliary drive winding excitation.The primary research of this paper includes the following aspects:(1)Based on the analysis of motor topology and operation principle,the four operation modes of the motor are described,and the mathematical model of the dual five-phase hybrid excitation permanent magnet motor with multiple operation modes in the rotating coordinate system is deduced based on the double dq transformation theory,combined with the feature that the auxiliary drive stator winding can regulate the main drive air gap magnetic field,and a simulation model is built to compare and analyze the differences of the four operation modes,which verifies the correctness of the mathematical model and the feasibility of the four operation modes,and lays a theoretical foundation for the subsequent construction of the optimal torque distribution control strategy under the minimum copper consumption constraint and the wide speed domain weak magnetic control strategy;(2)Using the Lagrange multiplier method,the optimal torque distribution control strategy under the minimum copper consumption constraint is proposed.Considering the complexity in solving the optimal cross-direct axis currents of the main drive and auxiliary drive,the corresponding Lagrangian equations are constructed to solve the optimal currents by combining the characteristics of each operation mode,and the optimal torque distribution of the four operation modes is solved by its association with the torque equation.After that,the proposed control method is verified by comparative simulation,which proves the effectiveness of the control method and improves the motor operation efficiency.The efficiency of several operation modes at the whole rated operating conditions is compared and analyzed,and the motor operating conditions are subdivided to give the high efficiency interval of the motor operation;(3)In the traditional voltage feedback weak magnetic control,the PI regulator is easy to saturate in the high-speed operating range,resulting in large d-axis current and terminal voltage pulsation amplitude,which is not conducive to stable system operation.Therefore,this paper proposes a new weak magnetic control algorithm,in which the feedback speed,the critical torque calculated from the main drive stator cross-axis current and the motor output torque are compared as the basis for the determination of the flux weakening control of the system,when the motor output torque is greater than the critical torque,the motor enters the flux weakening control,the electromagnetic torque determines the q-axis current,and the d-axis current correction value Δid is determined by the voltage limit circle and the optimal current,resulting in a more accurate d-axis reference current to realize the weak magnetic operation of the motor;(4)The experimental platform of the prototype drive system based on RT-BOX 204 real-time controller is built,and the optimal torque distribution control strategy under the minimum copper consumption constraint and the new flux weakening control algorithm are verified experimentally.