Louis Cheng

DSP-based variable speed motor drive with power factor correction and current harmonics compensation

The DSP-based variable speed motor drive consists of an active rectifier and inverter, which generates low current harmonics and low reactive current for efficient power conversion. The active rectifier converts the AC voltage into a regulated DC voltage, and draws input sinusoidal current at near unity power factor. In addition, the output inverter generates a variable frequency PWM synthesised voltage waveform to drive a permanent magnet brushless DC motor at near unity power factor for maximum efficiency. The high efficiency motor drive requires a small passive EMI filter and lower power rating requirements for the electronics switching devices. Therefore, the new DSP-based motor drive can be packaged into a smaller and lighter unit.