Permanent magnet drives with reduced dc-link capacitor for home appliances

This paper proposes a control strategy for drives in home appliances with small energy storage in DC-link. The examined system consists of a single-phase diode rectifier, a small DC-link film-capacitor, a three-phase inverter and a permanent magnet synchronous motor (PM). With a small DC-link capacitor (less than 11 ¿F/kW) an approximately trapezoidal torque is generated by the PM in each half-cycle of the mains. For home appliances motor-torque variation with twice the line frequency is widely accepted. The method is based on the field-oriented control and uses the modulation of the d-q-axis currents of the PM. Simulations and experimental results in this paper demonstrates the feasibility of this method.