DSP-based sensorless speed control drive system for two-phase synchronous motors

A basic direct torque control (DTC) drive system enables effective control of stator flux modulus and electromagnetic torque. This high performance method can be further improved to a sensorless speed control method, which adjusts the stator flux modulus and motor speed. Based on the DTC method, this paper proposes a sensorless speed control drive system for two-phase synchronous motors. The block diagram of the two-phase sensorless speed control drive is proposed. The small-signal model of the system is then derived based on the proposed block diagram of the system. Based on the small-signal model of the system, the phase margin and crossover frequency of the gain of the control loop are calculated and then used for the design of the speed controller. The design process of the speed controller is verified using Bode plot. The effectiveness of the proposed two-phase sensorless speed control drive system is validated by an experimental setup using a TMS320F2812 digital signal processor (DSP).