A design of sensorless permanent magnet synchronous motor drive based on V/f control

Aiming at the application of fan, pump and compressor load, a cost-effective sensorless drive control system of permanent magnet synchronous motor (PMSM) based on V/f control is proposed and realized in this paper. Aiming at the problem that conventional V/f control cannot maintain the stable operation in middle and high frequency domain and the load fluctuation, a method of adding the speed stabilizing loop is proposed. A method of extracting the perturbation component of the active power to compensate the given frequency is used to solve the problem. Perturbed active power is obtained by using the first-order high-pass filter to filter the input active power of the motor, and then the negative feedback for a given electrical frequency is realized. Simulation and experiment results show that the method has good adaptability and robustness to the load change, and verify the correctness and feasibility of the control method.