Pulsating torque control with voltage suppression period for position-dependent load torque applications

This paper proposes a pulsating torque control with a voltage suppression period, which is effective in reducing energy consumption and suitable for position-dependent load torque applications. The proposed control method is based on extracting the fundamental periodic component as a sinusoidal variation by applying a simplified Fourier transformation algorithm. The energy consumption can be reduced by paying attention to the period when the supplied voltage becomes relatively high. One original key component in this paper is a mechanical angular position detector, which adjusts the phase compensation value of the tentative mechanical angular position by applying the relationship between position-dependent load torque periodicity and the distinct point of the superimposed sinusoidal q-axis current command. Simulation results and experimental results detail behaviors of the mechanical angular position detector and the improved pulsating torque controller and their effectiveness. Moreover, the effects of the proposed method were clarified by results of an experiment in which a refrigerator equipped with a reciprocating compressor was used as an actual verification application. Simulation results and experimental results validate the energy-saving effect of the proposed control method.