Research On Power Quality Compensation Method Based On Fixed Frequency Direct Power Control

As an indispensable energy for human beings,electric energy is widely used in many research fields and daily life.It is often used to measure the development level of a country’s science and technology and economy.With the accelerating pace of industrialization and electrification in China,electricity demand is growing day by day,and the measurement index of power quality is also getting higher and higher.The standard power quality can not only guarantee the normal life of power users,but also play a key role in the safety of power grid and power production equipment.However,in the increasingly large power grid system,due to the complexity and diversity of power quality problems,all kinds of power quality problems always occur at the same time.Compared with the power quality compensation with a single goal,the research on the comprehensive compensation of power quality has more practical significance and value.This article set out to study the comprehensive compensation of the power quality control method,in view of the current harmonics,reactive power compensation,and the problem of three phase current,first introduced about research significance and research status quo of the problem of power quality,and then select a LCL three-phase active power filter topology structure,equivalent analysis was carried out on the LCL filter.The mathematical model of active power filter is established,and the compensation control method of power quality is studied.The traditional fixed-frequency direct power control adopts the PI controller plus power feedforward decoupling control,because the PI controller’s parameter calculation is complicated,the uncertainty is great and so on.Therefore,a constant frequency direct power control method based on model prediction is proposed in this paper.According to the basic principle of model predictive control theory,in order to output the optimal voltage vector and minimize the objective function after building the objective function,the partial derivative method is adopted to eliminate the need for repeated iterative calculation and reduce the calculation amount.At the same time,a feedback correction link is introduced to correct the output error signal of each cycle,so as to realize the non-static tracking of power.Finally,the simulation model of the system is built in Matlab /Simulink,and the dynamic response speed,overshooting and harmonic compensation effect of the two control methods are compared and analyzed.Then,the experimental platform of the system is built,and the code automatic generation technology based on DSP TMS320F28335 is used to design the program,and the traditional fixed frequency direct power control and the improved model predictive power control are verified by experiments.