AC-AC single-phase DC-link converter with four controlled switches

An unidirectional single-phase to single-phase component minimized dc-link converter is discussed in this paper. It is composed of one unidirectional rectifier and one bidirectional inverter, using only four controlled switches. Suitable modeling and control strategy of the system, including a synchronization method, are proposed. The synchronization method, associated with the PWM command, guarantees a sinusoidal input current with the same phase angle of the input converter voltage. In this approach, the output converter voltage is also in synchronization with the grid. Proposed method eliminates zero-crossing distortion caused by the use of diodes, as well. Additionally, the control strategy permits the converter to operate with same dc-link voltage value required for the conventional six-switch converter. Simulated and experimental results are presented.