Effective Controls of Fixed Capacitor-Thyristor Controlled Reactors for Power Quality Improvement in Shipboard Microgrids

Addressing power quality issues in shipboard microgrids (SMs), which are mainly attributable to the increased installation of power converters, has received much attention recently. To this end, static VAR compensators, such as thyristor-switched capacitors and fixed capacitors-thyristor controlled reactors (FCs-TCRs), can be effective solutions. Controlling these compensators, however, is not a trivial task as it involves sophisticated operations, especially estimating the firing angle, which should be carried out based on some nonlinear equations. This article aims to propose the application of some simple yet numerically efficient algorithms based on bisection, Newton-Raphson, false position, and secant methods for estimating the firing angle of the FC-TCR. The effectiveness and robustness of these algorithms are demonstrated via modeling of the FC-TCR with the electrical power system of a practical hybrid ferry under MATLAB/Simulink environment, where the results proved that the enhanced power quality issues respect the IEC standards 61000-4-7/30. Furthermore, an experimental setup consists of a digital signal processor and a programmable source is used to demonstrate that these techniques can be effectively applied in real-time applications.