Research On A New Reactive Power Compensator Based On DC Side Capacitance Minimization And PWM Pulse Width Modulation

With the increasing demand for electricity,the existing energy can no longer meet the needs of daily life and industry.There are mainly two solutions:First,the development of new energy;the second is to improve the current power utilization.The development and utilization of new energy mainly includes wind power generation,nuclear power generation,and solar power generation;and reactive power compensation technology has been widely used as one of the main ways to improve the utilization of electric energy.In this paper,a new full-bridge reactive power compensation technology based on DC side capacitance minimization and PWM pulse width modulation is proposed,which not only solves the slow response and harmonic response of the traditional magnetic energy recovery switch;but also it solves the problem of large capacitance required by traditional STATCOM,reduces the floor space and construction costs,and has higher safety and reliability.This paper first briefly introduces several typical topologies of the magnetic energy recovery switch,clarifies the basic principle of its use as a controllable capacitor,and further studies the magnetic energy recovery switch based on the Magnetic Energy Recovery Switch As a static Var Compensator Technology(SVC-MERS),it analyzes its main operating modes and performance characteristics.The results show that SVC-MERS can achieve a large range of reactive power compensation with a small capacitance,and the control is simple and easy to implement.However,the control strategy based on the phase angle also brings about a problem of slow response speed and large harmonic content deviation from the balanced mode.This paper clarifies the main problems of SVC-MERS,and proposes an improved PWM pulse width modulation method to replace the phase angle control of SVC-MERS.Combined with the small built-in capacitance of SVC-MERS and the traditional STATCOM,the response speed is fast and harmonic.With the advantage of small wave content,a new full-bridge reactive power compensation technology based on DC side capacitance minimization and PWM pulse width modulation was proposed-STATCOM-MERS.Secondly,this paper gives a detailed derivation and analysis of the new reactive power compensation device STATCOM-MERS,establishes a mathematical model,and analyzes the ideal waveform of DC measurement voltage under different working modes.The PWM pulse generation method under voltage fluctuation on the DC side is mainly discussed.Based on this,a DC-side voltage waveform direct control strategy based on DC-side capacitor minimization is proposed.Further,the parameter design method of STATCOM-MERS is studied in this paper,The design basis of the DC side capacitor is mainly discussed.and the optimal design of its rated operating point.And compare it with the traditional STATCOM parameter design.Thirdly,according to the principle of parameter selection and the proposed new control strategy,the reactive power compensation for single-phase and three-phase systems is modeled and simulated to verify the feasibility of the control strategy;and the STATCOM-MERS and SVC-MERS are also analyzed and compared in harmonic characteristics.Finally,the hardware circuit and software system of STATCOM-MERS are designed,and the experimental platform of STATCOM-MERS is built to verify the experiment.