Reduction the Dead-Time Effects on the Inverter in Renewable Energy Conversion Systems by Applying Sliding Mode Control

Even though dead-time prevents shoot-though in grid-tied inverters, it has some drawbacks, such as the harmonic distortion of inverter output voltages. This voltage distortion can spread into the inverter output currents if dead-time effects are not considered by the control system. Rejecting dead-time effects permits to improve the energy quality delivered into the grid by renewable energy conversion systems, which is an important concern. Therefore, to reduce dead-time effects on three-phase grid-tied inverters, a super-twisting sliding mode control algorithm is proposed in this paper. This algorithm has the following advantages: robustness against grid frequency variations, low chattering, and fast dynamics. To highlight these advantages, the proposed algorithm is compared against PI control. Simulation results of a three-phase grid-tied inverter switched at 40 kHz demonstrate how the proposed algorithm maintains the inverter output current TRD at 0.8%, when deadtime is equal to 1 μs, meeting Std IEEE 1547.