Design of optimal LMI-LQR based PI controller for modular three-phase quadratic boost converters in wind energy conversion systems to mitigate current harmonics

Abstract

The article proposes an innovative single-stage modular three-phase Power Factor Correction (PFC) converter featuring fewer current controllers. This technique leverages a practical DC-DC Quadratic Boost Converter (QBC) for PFC in Wind Energy Conversion Systems (WECS). An equivalent circuit with the non-ideal QBC is established and its small-signal model is derived, followed by a cascade control of inner current loops and outer voltage loops. The suggested linear quadratic regulator for linear matrix inequality-based PI control strategy ensures sinusoidal supply currents with a high power factor (PF) and low percentage Total Harmonic Distortion (THD) for line, servo, and regulatory operations, while addressing imbalances in the magnitude of the supply voltage. Additionally, the PFC method regulates the load voltage, and the minimal number of current controllers reduces computational tasks, losses, and overall cost. MATLAB/Simulink is used to simulate the suggested system, which uses the extended symmetrical components approach for reference current generation. The QBC's effectiveness is validated under diverse working conditions using a DSPIC30F2010 controller for a 300 W prototype. The results affirm the efficacy of the proposed technique, showcasing improved efficiency with fewer current controllers.