Research On Key Technology Of Permanent Magnet Synchronous Motor Control Of Mine Electric Locomotive

Traditional mining electric locomotive mostly adopted DC series excitationmotor as the traction motor which uses serial-resistance speed governing or chopperregulator. A small part of electric locomotives adopted three-phase asynchronousmotor as the traction motor which was frequency control of motor speed. The abovesystems, which had advantages of simple structure and operation, low initialinvestment, have been widely used in domestic mining electric locomotive. Withhigh demands for safety, efficiency, environmental protection and energy savingproposed by mining enterprises, it is particularly urgent to replace traditionaltechnology with high-technology. The control scheme of using permanent magnetsynchronous motor as the traction motor has many advantages such as simplestructure, high efficiency, good safety performance and reliable system, etc. In thefuture this kind of motor will has a broad prospect in mining industry.In view of the demand of mine electric locomotive traction and thecharacteristic of frequent use and bad environment, etc, traction control system ofsensor-less permanent magnet synchronous motor is considered as research object inthe dissertation. Key practical problems in mine locomotive traction are analysed,related control method is studied and applied to the speed control device of thesensor-less permanent magnet synchronous motor. Through massive practical work,the traction system can match the demand of engineering application. The studytakes into account both theory and practice, aims at practical problems in mineelectric locomotive control, and the main research works include the followingaspects:1、It is essential to obtain the information of rotor position and speed forsensor-less permanent magnet synchronous motor. A simple solution, that is rotorposition estimator based on the principle of phase lock loop (PLL), is proposed inthis dissertation. Furthermore, in view of generality of the mathematical model of three-phase ac motor. the dissertation originally proposed that static compensationvoltage model (SCVM) scheme which has been widely used in asynchronous motorsis applied to the position estimation method of permanent magnet synchronousmotor rotor. Result indicates that sensor-less permanent magnet synchronous motorvector control system using the rotor position and speed estimation showed gooddynamic and static performance.2、Aimed at effective control of motor speed and torque at low speed and zerospeed, two kinds of interior permanent magnet synchronous motor (IPMSM)sensor-less control methods at low speed, based on high frequency signal injection,are studied in the dissertation, namely high frequency pulse vibration voltageinjection method and high frequency rotating voltage injection method. Both controlmethod use extra high frequency voltage signal injection method. The error signal ofthe rotor position and speed estimation is extracted by proper signal processing fromthe motor high frequency current response. The design of high frequency injectionsimulation model can achieve stable and effective operation of the motor at lowspeed and zero speed. Simulation and actual application results show that the twomethods have good tracking effect to the motor rotor position and speed.3、According to the actual problems that permanent magnet motor drive devicehas poor heat dissipation, a new method, reducing the switch frequency ofpermanent magnet synchronous motor complex vector control,is proposed in thedissertation. Through the establishment of permanent magnet synchronous motorsensor-less vector control model, analysis of different controller performanceassessment shows that discrete vector current controller using the direct designmethod has strong robustness and optimal performance. Thus, the speed regulationdevice reduces the calorific value in the process of practical application. Theproblem of frequent protection caused by high temperature is solved and the systemis more reliable.4、The accuracy of the initial position detection of sensor-less permanent magnet synchronous motor decides directly the motor starting characteristics. It isdiscussed in the dissertation that two initial position detect methods of built-inpermanent magnet synchronous motor’s rotor based on both high frequency pulsevibration voltage injection and high frequency rotating voltage injection. The rotorinitial position can be got accurately in current response of motor. The simulationand actual application shows that the simulation model for the initial position iseffective and feasible. Thus, a critical problem that interior permanent magnetsynchronous motor rotor initial position detection under the sensor-less condition issolved.5、Under a lot of traction tests and field application, governor control circuit isdesigned to satisfy inverter control and electric locomotive control of highperformance digital signal processor. Key solutions used in the speed control devicesuch as how to obtain the rotor position and speed information, how to realize thespeed and torque control and how to reduce the switching frequency of powerdevices, are proposed to solve key problems about control. The engineeringapplication shows that electric locomotive system structure is more reasonable andhas reliable explosion-proof performance, electric braking function, smooth start andshort braking distance. Whether in driving process or braking process, it is step-lessspeed regulation and has small mechanical shock. The mechanical wear andmaintenance workload is reduced greatly. The mileage and service efficiency of thelocomotive are improved greatly at the same time. In short, permanent magnetsynchronous motor and its control system used in mine electric locomotives have theadvantages of safety, high efficiency and energy saving, etc.