Design Of Permanent Magnet Synchronous Motor Control System For Washing Machine

Compared with the other motors in washing machine,Permanent magnet synchronous motor(PMSM)has obvious advantages,such as high efficiency,energy saving,smooth running,simple structure and so on.PMSM control method is divided into three types:with sensor,with low cost sensor and sensor-less,and the last is the aim direction of the further development.However,sensor-less PMSM control method is still in the development stage,and many companies keep the technology confidential for commercial interest and technique security.In this paper,a motor driving system is designed for a foreign-made sensor-less PMSM used for washing machine,and the motor control operation is realized.Firstly,in this paper,the mathematical model and control principle of permanent magnet synchronous motor are analyzed and studied.A PMSM vector control system with double loop is built based on the control strategy of id?0.The widely used sensor-less control algorithms are analyzed,such as sliding mode observer and high frequency injection method.By analyzing the condition of the washing machine motor,the low cost control method for washing machine is studied.Based on the deep analysis of the V/F control,a rotor position detect method is proposed,in which the relevant parameters of the motor are fit by the experiment and the rotor position is directly calculated using voltage and current when the motor is in stable running.According to the motor control requirements,the hardware and software of the PMSM control system for washing machine are designed,with dsPIC30F4011 digital controller as MCU.The overall structure and hardware design of the system and the details,including inverter circuit,MOSFET driver circuit,CPU peripheral circuit,detection circuit and protection circuit,are given.The software includes the flow chart of main program,and emphasizes the software implementation of PWM interrupt service,speed PI control and SVPWM algorithm.Finally,the test platform of the motor control system with an optical encoder as position sensor is built.The testing begins with fundamental motor running for system validity and reliability.Then a lot of running test of V/F control is conducted to obtain the running parameters of varied loads.Thus the running load of washing machine is recognized and motor control parameter is adjusted accordingly.Finally,the rotor position detecting based on experimental parameter fitting is carried out.The feasibility of this method is tested and verified.