Sliding-Mode Control With Multipower Approaching Law for DC-Link Voltage of Z-Source Photovoltaic Inverters

Z-source photovoltaic inverters feature a unique topology and a special modulation strategy that enables a traditional two-stage system function through a single-stage structure. Therefore, Z-source inverters are expected to gain an extensive application when inputs change significantly. Given the objective of achieving DC-link voltage control based on small-signal model analyses, this study proposes a sliding-mode control method with a multipower approaching law (MPAL) for the DC-link control of inverters. This novel approach can solve the slow convergence rate and serious buffeting of the traditional sliding-mode control. The proposed approach makes the system state reach the sliding surface rapidly. The inherent buffeting of the sliding-mode control is simultaneously weakened and even eliminated in a few cases. The simulation and experimental analyses prove that the proposed sliding-mode control with an MPAL features significant advantages unlike the traditional sliding-mode control and provides a certain practical value.