Design Of High Voltage Permanent Magnet Synchronous Motor Control System In High Temperature Environment

The motor drive system for all-electric / multi-electric tanks works in the "triple high" operating conditions of high ambient temperature,high power supply voltage and high speed operation,which greatly affects the output characteristics and safety reliability of the permanent magnet motor and its controller.Therefore,research and design of high temperature,high voltage,high speed permanent magnet motors and their drive systems are of great significance to China’s all-electric / multi-electric tanks.This paper proposes a two-stage topology based permanent magnet synchronous motor loss minimization control strategy,designs a high-speed permanent magnet motor and controller,builds an experimental platform and verifies the feasibility of the designed motor control system.Firstly,optimize the design of the fixed rotor structure,permanent magnets and stator core materials,the main dimensions of the motor and other parameters,and use the finite element simulation software to simulate and analyze the electromagnetic characteristics,losses,and temperature of the motor.Using a multiphysics iterative method,a 1.5k W / 18000 rpm high speed permanent magnet motor is designed.And combined with technical indicators to verify the correctness of electromagnetic design.Secondly,research and put forward the control strategy of minimizing loss of permanent magnet motor under high temperature,high voltage and high speed.The influence mechanism between currenttime harmonics and motor loss is analyzed to determine the design direction of permanent magnet motor loss minimization.By analyzing the voltage harmonics of the driver under the SVPWM modulation technique,the numerical relationship curve between the modulation ratio and THD is obtained,and the optimal modulation ratio under the minimum motor loss is determined.Based on the above analysis results,a control strategy for a permanent magnet synchronous motor based on a two-stage topology is proposed and compared with the traditional single-stage three-phase full-bridge inverter control system.In addition,for the problem of large electromagnetic noise of the motor and driver under high voltage conditions,an EMI filter is designed to suppress the electromagnetic noise of the motor drive system.Finally,a simulation model of the motor control system is built in Matlab / Simulink,and a simulation comparison between the motor control system based on the two-stage topology and the traditional single-stage three-phase full-bridge inverter control system is performed.The hardware platform of the 900 V motor control system is designed and built.The experimental results show that the two-stage topology-based controller designed in this paper has the function of high speed motor speed regulation under high voltage,and embodies the advantage of the combined control of the front and back stages in reducing motor start current and motor loss.The experimental results of the motor shaft temperature rise verify the effectiveness of the strategy of reducing the motor temperature rise by increasing the modulation ratio.