An Improved Hybrid-Bridge Transformerless Inverter Topology with Bidirectional Clamping and Reactive Power Capability

Abstract

The building integrated photovoltaic (PV) central inverter architecture comprises various PVmoduleconfigurations. The PV module configurations are vulnerable to shading effects and cause mismatching power losses. To reduce the detrimental impact of shading and mismatching on energy production, the PV distributed-maximum power point tracking (D-MPPT) architec ture has been proposed. In this architecture, an individual dc–dc converter with an MPPT controller is integrated to each PV mod ule for extracting the maximum power. This topology is referred to as module-integrated-converter (M-I-C). In the conventional PV D-MPPT architecture, the output terminals of M-I-Cs are connected either in series or parallel configuration only. The conventional configurations of M-I-Cs have the drawbacks of cross-coupling effects, lower conversion efficiency, two-stage voltage conversion, etc. This paper proposes the total-cross-tied (T-C-T) configuration of string-integrated-converters (S-I-Cs) to overcome the drawbacks of M-I-C configurations. The detailed mathematical analysis of the proposed T-C-T configuration of S-I-Cs is also presented in this paper. The perturb and observe MPPT technique is used for extracting the maximum power. The performance of the proposed T-C-T configuration of S-I-Cs is analyzed under various partial shading conditions and also compared with the PVcentral inverter architecture as well as with conventional M-I-C configurations.