The Research Of Direct Torque Control System Based On DSP

The paper designs a kind of direct torque control system scheme which uses u-n stator flux observer model according to the direct torque control theory. This model is suitable for full speed. The u-n stator flux observer model uses model reference adaptive method according to the modern control theory. According to the system design scheme, the paper builds motor model under the two phase static coordinate using Matlab/simulink soft, and sets up the direct torque control simulation system which includes flux observer simulation model, torque observer simulation model, flux regulator simulation model, torque regulator simulation model according to motor's equivalent circuit. The paper researches the flux and torque of circular flux control at low speed, also studies the flux and torque of regular hexagon flux control at high speed. And according to inverter highest switching frequency permission scope, the paper analysis direct torque control performance at different switching frequency and defines effective switching frequency scope of the torque control. Because hexagon flux has the distorted phenomena at low speed, therefore according to the principle of flux value maintains invariable, we need to get the minimum speed when the circular flux handovers hexagon flux at different switching frequency. The simulation result indicated this system can control flux and torque well, the system has the good dynamic and stable state, it explains proposal accuracy and the feasibility of the direct torque control system design.At the same time, the paper takes DSP as a controller to design control circuit and driving circuit of three-phase inverter. The concrete circuit design includes voltage and current signal sampling and processing circuit design, photoelectric encoder signal sampling and processing circuit design, PWM drive circuit design, Thus the paper designs a kind of direct torque control hardware system using the DSP technology. The paper carries on the software design to the partial algorithm of the direct torque control under the CCS2.2 environment.