Research On The Control Strategy And Drive Control System Design Of Variable Operating Condition Permanent Magnet Motor

Permanent Magnet Synchronous Motor(PMSM)has advantages such as high efficiency,high power density,and high torque density,and has been widely used in fields such as electric vehicles and rail transit.Currently,the transportation environment is becoming increasingly complex,and the driving and riding conditions of vehicles are constantly changing,which puts forward strict requirements for the torque characteristics,speed range,efficiency,and variable driving performance of their electric vehicle drive motors.However,in high power density permanent magnet motors,the constant excitation magnetic field of the permanent magnet makes it difficult to adjust the air gap magnetic field of this type of permanent magnet motor,which limits the speed range of the constant power zone of this type of motor.In recent years,with the demand for high torque,wide area efficiency,and wide speed range of electric vehicles,Flux Leakage Controllable Permanent Magnet(FLCPM)motors have attracted the attention of many experts and scholars both domestically and internationally due to their characteristics of low speed,high torque,and wide constant power speed range.The air gap magnetic flux of this type of motor varies with the variation of the quadrature axis current,and has characteristics such as low flux under light load and high flux under heavy load.However,due to the adjustable characteristics of magnetic flux leakage,the air gap flux,inductance parameters,and other parameters of this type of motor undergo nonlinear changes with the increase of load.Under traditional magnetic flux weakening control algorithms such as voltage method and formula method,this often leads to problems such as excessive magnetic flux weakening and low control efficiency of the motor.Therefore,this article proposes a minimum speed control strategy for weak magnetic current based on the variation of the quadrature axis current magnetic field to control the main excitation flux of the air gap in this type of leakage controlled permanent magnet motor,and conducts research on the wide speed control drive control system of this type of FLCPM motor.The specific work content of this article is as follows:1)This article mainly describes the research background of this article,provides a detailed introduction to the current research status of variable operating condition permanent magnet motors and their drive control systems,analyzes the impact of the controllable magnetic leakage characteristics of FLCPM motors on their drive control,and explains the research value of this article.2)Analyze the basic structure of FLCPM motor,conduct in-depth research on the mechanism of weak field control of the quadrature axis current of FLCPM motor,and analyze the influence of the change rate of weak field current trajectory of FLCPM motor on the magnitude of weak field current of the motor.An experimental platform was established using the d SPACE1007 semi physical simulation platform to verify the characteristics of the quadrature axis current weak magnetic control.3)A minimum speed control strategy for weak magnetic current based on quadrature axis magnetic field regulation is proposed,which utilizes the quadrature axis magnetic field to reconstruct the distribution of id and iq currents during weak magnetic control,limitedly adjusts the leakage magnetic flux of the permanent magnet,and indirectly achieves air gap magnetic flux control.On this basis,in order to reduce the impact of leakage flux changes on current distribution calculation and demagnetization current calculation,the minimum is current weak magnetic constraint condition and online adjustment judgment are introduced to optimize the allocation amount of id and iq,improve the efficiency of weak magnetic operation,and verify the effectiveness of the control algorithm through the construction of a semi physical simulation platform.4)A drive controller for FLCPM motor was constructed using TMS320F28335 as the core processor,and corresponding driver program design was carried out.On this basis,research was conducted on the weak magnetic field control of FLCPM motor’s quadrature axis current,and the correctness and effectiveness of the minimum speed control strategy for weak magnetic current based on quadrature axis magnetic field regulation were experimentally verified.