An investigation on electrical performance of variable-frequency drives for air-conditioning applications

Variable-voltage variable-frequency (VVVF) drives has been widely accepted by electrical and building services engineers. Electronic variable-frequency drives have been widely adopted in the area of heating, ventilation and air-conditioning (HVAC) applications and became the substantial energy consumption in both commercial and residential buildings. Since the speed of the single-phase compressor cannot be varied, it is either switched ldquoONrdquo, working at maximum capacity or switched ldquoOFFrdquo by a thermistor. The magnet-assisted reluctance motor driven compressor delivers an enhanced performance over conventional AC induction motor driven system, providing variable-speed operation as the temperature changes, while improving the overall energy efficiency. This paper aims to investigate the performance of both conventional single-phase induction motor and the most recent variable-frequency DC motor compressor drives for residential air-conditioning applications. Their cooling performance and harmonic distortions will be investigated and compared.