A novel neutral current control strategy for the three-phase four-wire boost PFC converter

For higher power application, the six-switch three-phase boost rectifier is a preferred topology. Compared with three-phase three-wire boost rectifier, the three-phase four-wire input rectifier is more usually used in uninterrupted power supply (UPS) systems to prevent the load neutral from floating. In this paper, the four-wire input boost PFC rectifier is modeled and analyzed; the origin of the neutral current is analyzed; a novel rotating d-q-0 synchronous frame based space vector PWM control strategy is introduced to minimize neutral current. With this control strategy, the DC-link voltage is controlled constant and balanced. The three-phase input current is sinusoidal with a unity power factor. This control strategy can be used in the four-wire input AC/DC/AC converter and active power filter. A 40 kVA DSP (TMS320F2407A) controlled three-phase four-wire boost PFC rectifier prototype circuit is built to examine the character and verify the validity of the control strategy.