Single-Inductor Buck–Boost Inverter Based Transformerless Dynamic Voltage Restorer

In this paper, a single-inductor buck-boost (SIBB)inverter-based transformerless dynamic voltage restorer (DVR) is proposed. Since the conventional inverters operate in buck mode, the input dc source voltage should be higher than the compensating voltage. Therefore, the voltage level of the input source is important for the conventional inverters. Contrary to the conventional inverters, SIBB inverters can be operated in a wide input voltage range. Therefore, the proposed SIBB based DVR eliminates the high dc voltage source necessity. The control of SIBB based transformerless DVR is achieved by the super twisting sliding mode control (SMC) method. The effectiveness of the proposed SIBB based transformerless DVR and control method is investigated by simulation studies. The results reveal that the voltage sag and swells in the grid voltage are successfully compensated by the proposed SIBB based transformerless DVR. Moreover, the voltage compensation capability is tested for a large variation in the input dc voltage. It is shown that the proposed SIBB based transformerless DVR successfully compensates voltage deviations in the grid voltage under both buck and boost modes.