In this paper a power factor correction (PFC) buck-boost converter based adjustable speed voltage controlled voltage source inverter (VSI) fed permanent magnet brushless DC motor (PMBLDCM) drive is employed for an air-conditioning system for the improved energy efficiency. A single-phase single-switch AC–DC converter topology based on the buck-boost converter is employed for PFC which ensures near unity power factor in wide speed range. The speed control scheme has a new concept of DC link voltage control proportional to the desired speed of the PMBLDC motor. Moreover, the control of VSI is used only for electronic commutation of PMBLDCM. Therefore, the number of sensors is reduced as compared to conventional PMBLDCM drive. The proposed control scheme with a PFC converter based PMBLDCM drive is designed, modelled and simulated in Matlab–Simulink environment for an air conditioner compressor. The results obtained are presented to validate the effectiveness of the proposed speed control scheme with PFC feature in wide range of the speed and an input AC mains voltage. Copyright © 2010 John Wiley & Sons, Ltd.