| With the rapid development of power electronic technology, more and more powerelectronic devices used in industry and People’s daily life, it could bring not only convenienceand benefits, but also more and more serious harmonic pollution problem to power network.Active power filter as a kind of harmonic compensation was more and more attention inpower equipment and its related control algorithm research was one of the core issues. Butactive power filter was not widely used at home, and there were still many problems to besolved. Therefore, this article would focus on the control of active power filter algorithmin-depth research, the main contents included the following:(1) To develop a harmonic current detection method to inhibit voltage distortion effect:improve UPF (unit power factor) harmonic current detection method. This method did notneed to coordinate transform, so the algorithm is simple, and when the load changes, it alsohad a good dynamic response performance. In order to reduce the influence of voltagedistortion on the system, the phase-locked loop was introduced in the algorithm, thusimproved the traditional method of UPF.(2) To study a Space Vector Pulse Width Modulation SVPWM (Space Vector Pulse WidthModulation) method. Three-phase shunt active power filter (SAPF) reference instruction wasthe current value and SVPWM reference instruction is voltage value. Therefore this articleproposed the method how to use SVPWM control SAPF compensation current reference, andby constructing Lyapunov function, analysis the stability of the SVPWM to control SAPF.(3) To study the SVPWM controling three-phase APF method based on the LCL filter, andaccording to the topological structure based on the LCL filter SAPF, found the relationshipbetween the reference voltage of SVPWM and the reference current of three-phase SAPF.Through the relation, the SVPWM control algorithm was applied to SAPF based on the LCLfilter. And by constructing Lyapunov function, and in terms of the Lyapunov stability criterion,the SVPWM control was analyzed based on the stability of the LCL filter SAPF.(4) By switch control, APF nonlinear systems could be divided into a number of lineardynamic subsystem, this paper would switch control combined with space voltage vectorcontrol method, and a simple algorithm was designed. Just put the three-phase power supply voltage divide into six sectors, and then using the method of lyapunov function and globalprogressive quadratic stability theory, found out a very simple switching law, greatlysimplifying the algorithm. Due to the reasonable use of zero vector, the algorithm thussignificantly reduced the inverter switching loss.(5) In the practical engineering, the parameters are restricted rating, so it would be affected bysaturation nonlinearity. Based on problems in practical engineering, this paper put forward anew consideration of saturation limiting three-phase APF control method. According to thetheory of Lyapunov theorem, convex sets, convex combination conditions combined switchcontrol and SVPWM control method, for considering saturation limiting three-phase APFfound a new and simple stability criterion. Due to the reasonable application of zero vector,the algorithm thus significantly reduced the inverter switching loss.(6) To design the parameters of a three-phase APF of rated current of10A. By improving theUPF harmonic current detection method, this paper detected the harmonic current-instructioncurrent, and used considering saturation limiting three-phase APF control strategy to real-timecontrol of APF. Simulation analysis and experimental results proved the feasibility of theproposed method. |
