Patent ID: 8648556

Claim:
A device to control a permanent magnet synchronous machine, “PMSM”, including a stator and a rotor and powered by an inverter, comprising: a sensor to sample a measurement θ m of the position of the rotor; control means to control an operating point of the PMSM according to the position of the rotor and the settings; estimation means to determine an estimate {circumflex over (θ)} of the rotor position in an estimated Park frame of reference δ-γ associated with the rotor, where the estimation means include adjustment means to make said estimated rotor position {circumflex over (θ)} track said measured rotor position θ m ; a malfunction detector to detect a malfunction of the sensor; and a switch configured to connect the control means to the sensor in order that the control means receive measured position θ m of the rotor while the malfunction detector does not indicate any malfunction of the sensor, and otherwise to connect the control means to the estimation means in order that the control means receive estimated position {circumflex over (θ)} of the rotor when the malfunction detector indicates a malfunction of the sensor.