Research On Reactive Power Compensation Strategy Of Power Grid In Digital Control

With the continuous development of today's society,the problem of environmental pollution and energy scarcity on the earth is becoming more and more serious.most of the traditional energy on the earth is non renewable energy.Therefore,the energy problem has been constantly valued by people.It has become a hot topic in today's society.People are constantly looking for new sources of energy,such as solar energy and wind energy.They are now widely used in power generation.In order to maintain efficient utilization and stability of electric energy,reactive power compensation of power grid reenters people's field of vision.In order to improve the stability of power supply system and load operation,this paper begins with the harm of reactive power,and compares it with the traditional reactive power compensation method,which leads to the strategy of reactive power of the power system in the integrated control of the power system.It briefly introduces the origin and operation principle of SPWM modulation technology and introduces respectively,the operation characteristics of digital SPWM modulation technology and analog SPWM modulation technology and discuss their respective merits and demerits.By comparing the advantages and disadvantages of the two modulation techniques.A modulation method that combines the advantages of the two technologies of digital modulation and analog modulation is proposed.By compared with Fourier analysis,it proves that the Analog and Digital quantities modulation scheme is feasible.At the same time,the theoretical basis of reactive power compensation based on grid connected inverter is given,and the mathematical model is deduced.This paper analyzes the operation state of inverters for reactive power compensation.This paper describes the instantaneous current detection method for reactive power compensation in grid connected inverters.Based on the analysis of related mathematical models,the research derives a theoretical method for realizing instantaneous reactive power compensation formula based on dq two-phase rotating coordinate system.At the same time,the voltage and current double closed loop control strategy is introduced,which is the theoretical basis of PI control.This paper also analyzes the power compensation types of three phase grid connected inverters in different quadrants.The MATLAB simulation model of reactive power compensation is built based on the related deduction analysis theory.The feasibility of reactive power compensation for three-phase grid connected inverter is verified.This paper designs the signal processing circuit of the inverters and inverter main circuit board.The inverter signal processing circuit includes two parts: the digital modulation circuit and the analog modulation circuit.The experimental platform of three-phase asynchronous motor is built.The correctness of the inverter circuit board and the feasibility of the digital control strategy are verified through experiments.At the same time,the experimental platform of single-phase inverting and grid connection is built to verify the feasibility of realizing single-phase grid connected strategy through digital control inverter and the feasibility of reactive power compensation to the power grid.