1124 / 2019-05-20 23:21:38

DC Voltage Dependent Reactive Power Promoting Control Scheme for Voltage Source Converters

Reactive Power Capability,AC voltage magnitude,Total Harmonic Distortion,Flexible DC Voltage,voltage source converter

Rapid displacements of Synchronous Generators (SGs) by Voltage Source Converter (VSC) based Non-Synchronous Generations (NSGs) as results of increased exploitation of renewable power generations are expected to have adverse effect on AC grid voltage regulation because of limited Reactive Power Capability (RPC). Generally, capacitive RPC of VSC based NSG is limited by maximum AC voltage magnitude that VSC can produce from a given DC voltage (voltage limit). When VSC operating point surpasses voltage limit and crosses to over-modulation, the quality of its output voltage deteriorates with Total Harmonic Distortion (THD) infringes the maximum THD. To maintain VSC waveform THD under the permissible limit, a Flexible DC Voltage (FDCV) control strategy for VSC is proposed in this paper which aims to extend VSC voltage limit by modest increasing DC voltage level. The simulation results in MATLAB/Simulink prove the effectiveness of proposed DVRPP scheme in promoting VSC’s RPC.