Wide speed range sensorless control of PM-RSM via "active flux model"

This paper presents two improved control strategies for the sensorless control of permanent magnet reluctance synchronous motor (PM-RSM) in wide speed range. The first control strategy is a novel torque referencing strategy, which includes a reference torque calculator for maximum torque/ampere below base speed, and also in flux weakening region where voltage limitations impose constraints on the allowable dq-currents. The second control strategy is an alternative to the first one, with the advantage of being much simpler, involving less off-line computational effort. The PMRSM motion sensorless control is obtained via model-based "active flux" concept. Comprehensive digital simulations for wide speed range operating down to 1 rpm and up to 6000 rpm, demonstrate the effectiveness of both proposed sensorless control strategies. Experimental results between 30 rpm and 3000 rpm are in agreement with digital simulations and validate the theoretical background. The proposed strategies provide stable and reliable operation up to a speed equal eight times the machine base speed (CPSR = 8/1), at low (25%) rated voltage.