Research On Speed Sensor-less Direct Torque Control System Of The Asynchronous Motor Based On Fuzzy Logic Controller

Direct torque control (DTC) technique which was put forth after Vector control technique isanother novel control method for motor drives. DTC of induction machine developed greatly becauseof its simple system scheme, quick torque response, better dynamic and static performances. In thispaper, a speed sensor-less DTC system of the asynchronous motor based on fuzzy logic controller wasdesigned and the related experiments were done. The major work is included as follows:1. Designed a DTC system of the asynchronous motor based on DTC theory. The advantages anddisadvantages of traditional DTC were analysized and an improved strategy based on spacevector modulation (SVM) technique was proposed.2. A fuzzy model controller which was used to control the AC motor torque was designed and thecontroller was applied to the DTC system with space vector modulation technology. The controlsystem model was set up in Matlab/Simulink and simulated. The simulation results verified that thenew DTC system which combined space vector modulation and fuzzy control technology can wellimprove performances of the DTC system.3. Speed sensor-less technology was researched and Model Reference Adaptive System (MRAS)was adopted to estimate motor speed. Simulation model based on MRAS was established and thesimulation results proved that MRAS can estimate speed well.4. Hardware control system based on TMS320F2812DSP was built and the proposed DTCsystem experimented. The feasibility of the designed speed sensorless DTC system with fuzzycontroller was validated by experiment results.