A family of closed-form duty cycle control laws for three-phase boost AC/DC converter

In this paper, a basic closed-form duty cycle control law is first derived for the proposed AC/DC converter to achieve clean sinusoidal input current, adjustable DC voltage, controllable power factor and bidirectional power flow capability, and fixed switching frequency, without using any current sensor. Then, a second dead-band scheme is derived from the previous basic form to achieve the same function and to reduce switching loss and thermal stress. Similarly, a four-switch scheme is also derived to provide a new operation mode to enhance the reliability of the converter. Modified control laws of the above family are also considered to handle the effect of unbalanced input voltage. It is very interesting to see that a unified theory can be used to give the above family of duty cycle control laws under both balanced and unbalanced input voltage. Some simulation and experimental results are presented for verification.