Abstract
Voltage source converter based multi – terminal DC grids (VSC – MTDC) are widely used for integration of renewable resources. Control of these grids requires vector control method, which includes inner and outer current controllers, tuning of these controllers is very important. Conventionally used tuning methods consider approximated linear model to tune the proportional – integral (PI) parameters of voltage source converter (VSC) which fails to produce optimum disturbance rejection results. In this research an Ant Colony Optimization (ACO) technique is used to get the optimum parameters of inner and outer power control layers for multi – terminal DC system. ACO is applied simultaneously on inner and outer control layers and results are compared with classical tuning method and well established meta - herustic technique, Particle Swarm Optimization (PSO) using MATLAB software. Dynamic models of VSC – MTDC are developed in PSCAD/EMTDC to exalt the qualities of the presented tuning method. In this paper, a four terminal VSC – MTDC has been used under different sequence of events of disturbances e.g. load change on AC side, active power reference change for inverter and rectifier mode and disconnection of one terminal to evaluate the robustness of ACO algorithm with respect to classical method. The proposed tuning method gives superior results under different disturbance compared to conventional method.
Highlights
With the passage of time, contribution of renewable and clean energy is increasing in the conventional power grid
This paper focuses on the minimization of Integral Time Absolute Error (ITAE) performance index for inner current controller and outer active power controller
SIMULATION RESULTS In simulation section, initially inner and outer controllers are tuned by classical method; optimal parameters of both controllers are achieved by ant colony optimization (ACO) algorithm
Summary
With the passage of time, contribution of renewable and clean energy is increasing in the conventional power grid. Conventional tuning methods uses approximated linear model of VSC – MTDC to optimize the both inner and outer control loops. A probabilistic technique, ant colony optimization (ACO) is adopted to find the proportional – integral (PI) optimal parameters of inner and outer power controllers simultaneously, in terms of minimizing the Integral Time Absolute Error (ITAE). Generalized control structure of a voltage source converter (VSC) station using vector control method is shown in Fig.. Vector control method is a frequently used approach for reactive and active power control in voltage source converter (VSC) [26]. AC currents and voltages of VSC at PCC are transformed into rotating direct – quadrature (d - q) reference frame through phase locked loop (PLL).
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call