ABSTRACT
Venkataramanan (1993) proposed a method to add three-phase LC filter circuit between the PWM-VSI and the motor, which can reduce the volume and cost of the control system compared with the adding external inductances method. Caricchi & Crescimbini (1994), Zwyssig & Kolar (2009), Minshull & Bingham (2007), Minshull & Bingham (2010) proposed a method of adjusting the Direct Current (DC) bus voltage to improve the stator current waveforms for brushless DC (BLDC) motors. This method employs a halfbridge DC chopping circuit whose energy is bidirectional flowing in the front end of the PWM-VSI to adjust the DC bus voltage. Su & Adams (2001) adopted multilevel PWM-VSI to subdivide the output voltage and obtain more output levels, which will make the output waveform close to sinusoidal or square waveform. Current Source Inverter (CSI) was also applied to the low inductance motors. This method is always used to drive BLDC (Takahashi 1994, Woolaghan 2009) since the output of CSI is current.
