| Module integrated converter (MIC) can improve the energy efficiency of the solar power systems in both normal conditions as well as partial shade conditions. As a result, MICs receive wide attentions in the solar power applications. However, most of the recent research focus on MICs topology, efficiency and the series operation of MIC while there are few literature investigate load diversity performance of the MICs. This study mainly focuses on the three main issues of MIC, which are load adaptation, maximum power tracking, and series-parallel operation.Firstly, the operational modes of a MIC integrated PV panels are introduced, including:1. load operation; 2. battery load; 3. series output connected and grid-connected; 4. no-load operation. In this study, the boost topology MIC is selected, due to its continuous input characteristics; the working principles of the boost MIC are described in detail. The plant transfer functions under the output voltage control mode and the input voltage control mode are obtained using state space averaging method, based on which the close-loop controllers are designed.The steady state of MIC under different loads are compared. The advantages and disadvantages of MICs fast state transient are compared. The finite state machine for MIC is designed, which based on the control variables are analyzed under different load conditions. The finite state machine for MIC is proposed based on the signature analysis, with which fast state transient is achieved on the local control loop level.In order to achieve effective power tracking and attenuate the power oscillation around the MPP in steady state, the variable step incremental resistance method is proposed to track the maximum power. The PSIM simulation results prove the fast and accuracy of the proposed design.PV module integrated converters are completed. The prototype experiment results prove the finite state machine’s transient, MPPT, series and parallel operation for the photovoltaic solar systems. |
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