Adaptive Grid-Supportive Control for Solar-Power Integrated Electric-Vehicle Fast Charging Station

Though the Medium-voltage (MV) grid-connected solid-state-transformer (SST) based plug-in electric-vehicle fast-charging station (PEV-FCS) solutions provide a reduction in grid side current-stress, integration of solar-power in such SST-based PEV-FCS (which can potentially reduce grid side current-stress further) and its implementation with grid-compliant control is not explored in literature. In this paper, an adaptive automatic generation control supportive maximum power point tracking (AGCS-MPPT) technique for solar-power integration is proposed and experimentally validated for a bidirectional SST-based PEVFCS while following the EN 50530 standard's testing sequence. Respective European and Californian MPPT efficiencies (xi(Euro), xi(CEC)) of 99.50%, 99.55% and 99.49%, 99.55% are observed for solar-power integration through AGCS-MPPT technique during G2V and V2G functional modes of the PEV-FCS, which are better compared to those of state-of-the-art technique (SoAT) and improved perturb and observe (P&O) MPPT algorithms. Unlike the SoAT and P&O, the AGCS-MPPT algorithm assists the PEV-FCS in adhering to the utility grid's power ramp-rate constraint while integrating intermittent solar-power, both during xi(Euro)-test and xi(CEC)-test sequences. The AGCS-MPPT also displays excellent MPPT efficiency (similar to 99.2%) and solar-power integration performance during the dynamic-test sequence as perEN50530 standard. Grid side current's THD <2.2% and near unity power-factor (UPF) at grid side are observed during the experimentation of PEV-FCS under various solar-power penetrations.

Automated summary

This paper investigates solar power integration in a plug-in electric vehicle fast-charging station based on solid-state transformers, and experimentally validates the effectiveness of an adaptive automatic generation control supportive maximum power point tracking technique. The results show that the proposed technique improves solar power integration efficiency while adhering to grid-compliant control requirements.