Research On Control Strategy Of Permanent Magnet Motor Of Riding Mower

For the mowing equipment in garden tools,the traditional manual mower is not suitable for large-scale mowing.Oil powered lawn mowers also suffer from air pollution,noise pollution and high fossil fuel consumption.This paper studies and designs a kind of riding electric mower suitable for large-scale mowing.In the research and design of this paper,the riding mower is mainly divided into two parts,namely driving motor and mowing motor.The permanent magnet motor has the characteristics of high output efficiency,high power density and high output torque.Therefore,the two parts of the motor are permanent magnet motor.Considering the requirements of economy and applicability,the control strategy of driving motor adopts the position sensor vector control technology,and the sensorless six-step reversing method square wave control technology for mowing motor.The driving motor control circuit board,namely the main control circuit board,adopts STM32F103 RC as the main control chip to realize the control of the driving motor and the processing of each command;The control panel of mowing motor USES SPC5L32 ANL as the control chip,and UART protocol is used for communication between the two control panels.This paper first introduces the basic principle of vector control,studies in detail the principle of weak magnetic control,and the main reasons affecting the chattering of the motor speed in the weak magnetic area,and puts forward the improvement measures.The method can effectively reduce the chattering of the motor in the weak magnetic region.Secondly,the paper focuses on the hole-less sensorless square wave control technology of the permanent magnet motor,and designs a six-pulse positioning scheme,a no-reverse starting scheme,and a zero-crossing detection scheme of the antielectromotive force comparator,so as to realize the no-reverse starting of the motor.The scheme is applicable to different parameters of the permanent magnet motor and different load conditions.According to the actual working situation,the braking mode is studied,the braking time is short and the braking current is small,and the UART protocol is designed to realize the communication between the two control panels.Finally,the above theory is verified by experiments,the hardware schematic diagram and software code are designed,and the feasibility,reliability and efficiency of the scheme are verified.