Research on an Adaptive Compound Control Strategy of a Hybrid Compensation System

Abstract

This paper investigates the parallel harmonic resonance problem for hybrid compensation systems, consisting of active power filters and thyristor-switched capacitors, and proposes an adaptive composite control strategy for solving the parallel harmonic resonance problem that may arise in practical applications of hybrid compensation systems. In practice, a hybrid compensation system can effectively solve harmonic and reactive power problems, but the equivalent reactance of the thyristor-switched capacitor and the supply line may form a parallel resonant circuit, which may generate parallel harmonic resonance when excited by a harmonic source at the non-linear load side, affecting the quality and stable operation of the system. The adaptive composite control strategy employs a second-order generalized integrator-frequency-locked loop (SOGI-FLL) to extract the harmonic voltage at the point of common coupling (PCC) and generate an adaptive damping current command using an adaptive algorithm, which adaptively adjusts the parameters of the resonance suppression controller through harmonic content limitation. Matlab/Simulink simulations show that the method effectively achieves harmonic resonance suppression of the power supply system under complex operating conditions, thus ensuring the stable operation and power quality of the power supply system. Therefore, the proposed control strategy is feasible and effective.

Analysis of D-Q small-signal impedance of back-to-back frequency converter

“…The fractional frequency transmission system (FFTS) is a new type of transmission method, which changes the 50 Hz frequency power to 50/3 Hz frequency power during transmission. The equivalent impedance of transmission lines can be reduced and the power transmission capacity is improved through this type of system (Li et al, 2019;Pan and Wu, 2022;Wang et al, 2006;Wei et al, 2015;Alam et al, 2023;Wang et al, 2013;Wang et al, 2023;Fang et al, 2018). The development of offshore wind power generation has provided a new application to fractional frequency transmission system.…”