Research On Multi-objective Optimized Magnetic Energy Recovery Switch And Applied As Reactive Power Compensator

Reactive Power Compensator(RPC) is crucial for the stable and safe operation of power system. Traditional RPCs usually suffer with some inevitable drawbacks. For instance, synchronous condenser gets low efficiency, high noise and high cost. TCR has poor current quality and small reactive power capacity. Although it performs fast response and high control accuracy, STATCOM is flawed for its control complexity and poor stability.A novel continuous RPC, named magnetic energy recovery switch(MERS), is proposed in this paper. Some advantages of this new reactive power controller include simple structure, line frequency control, low cost, less loss, better reactive power capacity and high stability. Main work of this research, such as MERS’s circuit structure and operating principle and mathematical model and control strategy and applications, has been separately completed by theoretical analysis, simulation and experimental verification and it is introduced as following:Firstly, the importance of RCP is clearly pointed out in introduction. Types of RCPs, as well as characteristics comparison between the main shunt RCPs, are also mentioned. Research status and disadvantages of MERS are introduced and analyzed, respectively. As a result, the contents and creative technologies of this study has been determined.Secondly, MERS’s operating principle and mathematical model are firstly introduced as well as its voltage and current waveforms. Based on theoretical analysis and deduction, an equivalent capacitance model with double variables(α, VC-min) is built and its features on reactive power control are also analyzed. Some shortcomings, such as bad current quality and high capacitor voltage and small reactive power capacity, are revealed for traditional control.Thirdly, multi-objective optimization control technology is proposed based on traditional single variable phase delay control. According to double control parameters regulation, optimization allocation of control parameters technology(OACPT) is applied and simulation results support performance improvement on current harmonic suppression and capacitor voltage reduction. Reacitve power capacity of MERS is finally enhanced with a new designed parameters optimization scheme.Fourthly, MERS+TSC is proposed to regulate the grid power factor by supplying continuous reactive power. Power balance model and continuous reactive power model are deduced for the researched system. Method for the best working point selection is established as well as its evaluation standard. And simulation results have verified its performance.Fifthly, MRES is applied to regulate output voltage of induction generator in wind power generation system. Operating principle of induction motor is firstly analyzed when it works as a generator. Characteristics of this generator, including the reasons why voltage becomes unstable alone with load changing, is especially introduced. MERS+FCs is proposed to complement exciting current for induction generator when load is changed. Flywheel is used to balance grid frequency in the simulated wind power generation system. Load forecasting strategy, demonstrated by simulation, is designed for system control.Sixthly, a three phase MERS is firstly developed for experimental verification. Experimental systems, include grid power factor correction system and island wind power generation system, are established. Experimental results are obtained and they support the desired performance.From the above, work of this study is summarized and concluded. What’s more, the future work is also presented at the end of this paper.