PMSM sensorless control with Direct Flux Control for all speeds

A sensorless method named Direct Flux Control (DFC), which only requires the different voltages between a neutral point of permanent magnet synchronous machine (PMSM) and an artificial neutral point during switching states of pulse width modulation (PWM) signals, is implemented on a real time system with a PMSM. The DFC method is a continuous excitation method and can attain the estimated rotor position for all speeds. Moreover, in this paper the estimated position is assured as the exact rotor flux position, which is strongly needed in almost of the motor control schemes. The investigation of the DFC structure has been proposed and achieved, which allows for the frame conversion calculation. The derivation of the frame conversion is included. Furthermore, the closed loop sensorless speed control with DFC is also proposed and implemented. The proposed scheme can accurately perform with high robustness. All experiments and results of each part are elaborated, discussed and analyzed.