Research And Design Of Active Power Filter Based On Space Vector Model Predictive Control

With the development of modern industrial technology, nonlinear load gradually increased in the power system, injected a lot of harmonic current to the grid, power quality problem is becoming more and more serious. Compared with the passive filter, active power filter(APF) with its high degree of controllability and good compensation performance is becoming a hot spot of research. At present, the control method of active power filter is varied, among them, model predictive control is widely concerned with its parameters are easy to design, fast dy-namic response, easily apply to nonlinear system and so on, has a broad application prospect, severely limits the development of model predictive control. Therefore, this dissertation selects the active power filter based on space vector model predictive control as the research subject. The main research contents are as follows:First, on the basis of analyzing the current main topology of active power filter, consider-ing that the LCL filter has better filtering capacity and smaller volume than L filter, determine the topological structure of the three-phase shunt active power filter based on LCL filter, de-scribed its working principle, established the mathematical model of the system in the abc coordinate, ?? coordinate and dq coordinate, due to the variable in the ?? coordinate does not exist coupling relationship and easy to analyze, selecting ?? coordinate mathematical model as the basis of later analysis.Second, focus on the primary key technology of APF, the harmonic current detection tech-nology. Detailed analysis of the two methods widely used in engineering, that are based on Fourier analysis method and based on synchronous reference frame(SRF) method, aiming at the shortcomings of Fourier analysis method has large amount of calculation and exist time delay when calculate suddenly changed load and conventional SRF method cannot detect the selected order harmonic, this dissertation proposes a generalized SRF detection method on the basis of conventional SRF method, this method not only detects the selected order harmonic and reactive components,but also has small amount of calculation and fast response speed.Third, focus on another key technology of APF, the inverter control technology. This dis-sertation adopt current inner and voltage outer dual closed-loop control strategy, which the cur-rent inner loop control using model predictive control based on voltage space vector, in combi-nation with the principle of Space-Vector-Pulse-Width-Modulation(SVPWM) control and Fi-nite-Control-Set-Model-Predictive-Control(FCS-MPC), reduce the amount of computation by improving model predictive control, then aiming at the inherent shortcomings of unfixed switching frequency, high request to the device and exist steady state error, combining with the characteristics of them, proposed a model predictive control based on space vector. The control method has the characteristics of high utilization of DC voltage, fixed switching frequency and zero steady-state error. The voltage outer loop control method adopts controlling the active current to maintain the DC voltage stability.Fourth, using the MATLAB/Simulink tool to build the simulation model of active power filter based on space vector model predictive control, comparative analysis of the steady-state and transient characteristics of the system under the condition of balanced load and unbalanced load.Fifth, on the basis of theoretical analysis and simulation, the main circuit, control circuit and control software were designed. Among them, the main circuit design includes the design of LCL filter, DC voltage reference and capacitance, intelligent power module. The control circuit includes the design of voltage sampling conditioning circuit, current sampling condi-tioning circuit, and zero-crossing detection circuit. The software design of the control system gives the flowchart of main program and interrupt program. According to the above design, an engineering prototype of active power filter based on space vector model predictive control was built; verify the correctness of the theory described in this dissertation through the experiment of the engineering prototype.The results of simulation and experiment show that the designed APF not only suppress harmonics, compensate reactive power and improve the three-phase unbalance, but also re-mained stable DC voltage which verifies the correctness of the theory described in this disser-tation, the APF plays a guiding role in engineering practice and application value.The research in this dissertation was supported by the project of National Natural Science...