Motion Control Engine Achieves High Efficiency with Digital PFC Integration in Air Conditioner Applications

Permanent magnet motors are commonly used in AC inverter controlled air conditioner systems for home appliances. Acoustic noise and vibration reduction in the outdoor unit compressor is an important task, in addition to attaining high efficiency power usage. It is also required to eliminate motor position sensors such as Hall effect sensors due to the structural constraint of sealed compressors. These requirements naturally lead manufacturers to incorporate sinusoidal sensor-less PM motor control. Today, most air conditioner units are based on 32 bit RISC microcontrollers to achieve compressor motor control. In outdoor unit air conditioners, not only does the compressor use an AC inverter but also the fan uses an AC inverter. The fan is also based on a PM motor and its control is based on Hall effect sensors in today´s system. Power factor control is also required for a certain power range of air conditioner, which has normally been implemented by separate analog PFC control IC. This paper discusses a hardware computation-based dedicated controller for air conditioner applications that enables sinusoidal sensorless PM motor control for both compressor and fan, and digital PFC within a single monolithic silicon platform. Sensorless field oriented control (FOC) is implemented using an embedded motion control engine (MCE) so that computation power can be attained with two motor FOC controls and digital PFC combined