A novel reference compensation current strategy for three-phase three-level unity PF rectifier

The three-phase three-level unity PF rectifier can be used to improve the power factor of a three-phase rectifier. However, its ldquocritical input inductorrdquo is calculated for the nominal load condition, both the power factor and total harmonic distortion are degraded in low-output power region. A novel strategy implementing reference compensation current is proposed based on the operation principle of this rectifier. This strategy can realize three-phase three-level unity PF rectifier. With the proposed control algorithm, the converter draws high-quality sinusoidal supply currents and maintains good dc-link-voltage regulation under wide load variation. Theoretical analysis is verified by digital simulation.