A Control Scheme for a Combo 1-Ph/3-Ph PFC Rectifier With Improved Leg Utilizations

This letter proposes a control scheme for a single-phase (1-ph)/three-phase (3-ph) compatible PFC rectifier in electric vehicle on-board charger applications, which enables hybrid-mode control for different half-bridge legs. By utilizing the capacitor leg to take half of the return current in the 1-ph mode, the leg utilizations can be enhanced with balanced current stresses. Thereby, the 1-ph operation can output 2/3 of the 3-ph rated power, which improves 100% power transfer capability. With the proposed method, there is no need of a fourth half-bridge leg or any over-design of components. The proposed scheme also applies to inverter-mode operations and facilitates the control design of both 3-ph and 1-ph operations in the same control framework. Experimental results confirm the validity of the proposed method.