Adaptive DC-Link Voltage-Controlled PV Grid-Connected DTL-VSI With Reduced Switching Losses and Switching Frequency

This article discusses a photovoltaic (PV) grid-connected dual two-level voltage source inverter (GCDTL-VSI) to improve the power quality, reliability, and efficiency of the grid. In PVGCDTL-VSI, VSI-1 is employed to compensate the current-related power quality concern, while VSI-2 is employed to transfer real power to the load and grid. In the literature, the dc-link voltage maintains constant at the input terminal of VSI-1 under low-power injection. As a result, there will be significant switching losses and stress on the inverter switches. In the proposed method, VSI-1 with LC-filter, and an adaptive dc-link voltage control technique is used to alleviate the switching losses and stress on the inverter switches. In addition, the two-leg VSI that employs for supply real power to the load and grid instead of the conventional approach uses three-leg VSI. In PVGCDTL-VSI, a model predictive control (MPC) with a multiconstraint technique is used to generate the switching pulses, dc-link capacitor voltage balancing, and reduce switching frequency. To reduce the weighting factor control complexity, a technique for order preference by similarity to ideal solution (TOPSIS) approach is employed in PVGCDTL-VSI. To evaluate the effectiveness and performance of the PVGCDTL-VSI, simulation and experimental tests are carried out.