A Digitally Controlled 4-kW Single-Phase Bridgeless PFC Circuit for Air Conditioner Motor Drive Applications

Today's air conditioner applications demand a one-chip solution that simultaneously controls power-factor-correction (PFC) frond-end and two permanent magnetic (PM) motor sensorless drives, by using a single digital control IC. However, digital control has fundamental limitations that make most of conventional digital PFC control approaches unpractical. Implementation and integration of PFC control into digital ICs have been a quite challenge. International Rectifier recently introduced a new digital control IC that is based on the hardware computation engine called motion control engine (MCE). Unique advanced digital PFC control algorithms have been developed, and it becomes practical to integrate digital PFC with 2 PM motor sensorless control into a single digital IC. Based the new control IC, a 4-kW air conditioner outdoor unit which uses a bridgeless PFC frond-end has been designed, built and tested. This paper analyzes the fundamental limitations of conventional digital PFC control, presents the design and implementation of the 4-kW unit, and experimentally demonstrates the superior performance of the proposed digital PFC control