STUDY ON HARMONIC-REACTIVE-POWER-BASED ROTOR POSITION-SENSORLESS CONTROL OF SERVO MOTOR

点击翻译按钮获取中文摘要

In this research topic, a rotor position sensorless control strategy of an AC servomotor has been focused on. The proposed method is based on phase information of harmonic reactive power, which is generated by injected current or voltage harmonics. The feasibility of the method has been examined through computer simulations and experimental tests setting up a prototype. Through this study, the following results have been obtained :(1) A novel control strategy of a permanent magnet motor without mechanical sensors has been proposed. The strategy is based on use of harmonic reactive power and utilizes its relative phase information to estimate the rotor position. The key feature of the method is overall robustness against the motor parameters.(2) According to the initial rotor position estimation test, the position has been estimated with the maximum estimation error of ±10 (deg) and 3σ deviation of 12.6 (deg). The estimation was insensitive to the armature resistance variation.(3) In transient state sensorless operation, quick speed response of 200 (ms) and disturbance response of 800 (ms) have been obtained.(4) The control system is capable to four-quadrant drive and can be loaded up to 80 % in motoring modes and up to 100 % in regenerative modes. Also, similar performance was confirmed even under the condition of varied armature resistance by 25 %.(5) A disturbance compensation technique and current controller compensation technique have been discussed to enhance the further performance.(6) Field-weakening control with harmonics injection has been discussed. Operating performance in the higher-speed range was improved taking voltage saturation into account.