Wide-speed range sensorless control of an AC PM motor using the PWM waveform of a matrix converter and without di/dt sensors

The principle of position estimation and sensorless control of a matrix converter fed permanent magnet synchronous motor (PMSM) has been reported before, where the current derivatives of motor line currents were measured by di/dt sensors to construct position signals. This paper presents a different implementation that eliminates the di/dt sensors. The current derivatives are calculated by measuring current changes within certain vectors. Experimental results show that the performance of sensorless control is not compromised compared with that achieved by using the di/dt sensors. Additionally, careful selection of current measurement instants ensures no higher current ripples are introduced.