Fan Drive Starting into Naturally Rotating Load by Sinusoidal Sensorless Permanent Magnet Motor Control

A permanent magnet (PM) motor is a primary motor of choice for small fan motor drive applications. A traditional fan drive based on a permanent magnet motor uses position feedback sensors such as Hall effect sensors. Recently PM motor drive with sinusoidal current and no position sensor has been demanded for many applications including air conditioner outdoor unit fan control. Some fan and pump applications require that the drive has to start into naturally forward rotating load without stopping the load first. In case of the drive without the position sensor, the task of transition without regeneration capability is more elaborate due to the fact that speed reversal is required without position sensing. This paper describes a new algorithm for starting a PM motor drive into the forward and reverse naturally rotating load, where drive system does not have a regeneration capability and has only one current feedback sensor installed in the DC bus link. The algorithm is implemented on a chip belonging to a new motion controller family, which has been recently introduced by International Rectifier. The chip features a hardware computation engine, called motion control engine (MCE), for sinusoidal sensorless PM motor control. Experimental results are included