Position controlled permanent excited synchronous motor without mechanical sensors

The pole position and the rotor speed of a permanent excited synchronous machine can be estimated by a Kalman filter using only the voltages and currents of the machine. This replacement of the mechanical sensors by a Kalman filter reduces the volume of the motor and increases the sturdiness of the drive. In this paper, the application of a sensorless operating synchronous machine using a Kalman filter in an indirect position controlled drive system is described. The actual position, necessary for the position control, is determined indirectly by converting the estimated pole position to the load side. Such a drive system operates without any mechanical sensor. By impressing a current in the direct-axis of the motor, the Kalman filter can also estimate the pole position of an unloaded drive at standstill. Practical tests verify this method. The given practical results prove, that the application of a sensorless drive in an indirect position control is possible. A realization of such a sensorless position control in a robot with integrated drives is planed