Cascaded LMS Filter-Based Control to Integrate Load Compensation Features in SPV-SyRG-Wind Based Grid-Interactive AC Microgrid
Gaurav Modi, Bhim Singh
Abstract
Performance indices of a grid-interactive microgrid fall off and defy the set IEEE std. 1547, when the loads connected at its point of common coupling (PCC) draw unbalanced/distorted currents. In this context, this work introduces a cascaded least mean square (C-LMS) algorithm-based harmonics mitigation and compensator method to integrate the load compensation features in a solar photovoltaic (SPV) and wind-energy-based microgrid response. In the considered microgrid, the SPV array and wind turbine are coupled to the local grid through their separate power converters, i.e., voltage source converter (VSC) and back-to-back VSCs. The presented C-LMS filter is used as a prefilter to segregate the harmonics components from sensed load currents, and they are applied to control the grid-side power converters of the SPV array and wind turbine for integrating load compensation features. As a result, the microgrid performance does not affect by local loads and adheres to IEEE std. 1547, validated by simulation and experimental results. This C-LMS algorithm uses two LMS blocks to attenuate the harmonics components. Simulation analysis and experimental results reveal that it performs better than the cascaded second-order generalized integrator (C-SOGI), a well-acknowledged algorithm to filter the unbalanced/distorted voltages or currents. In addition, its structure is simpler than the C-SOGI method as it does not require any matrix structure, such as Park's transformation matrix, when the compensation for both load harmonics currents and reactive power, is implemented.