Design Of Cascaded Active Power Filter

Along with the development of power electronics technology, as well as improved requirement of power quality, harmonic suppression and reactive power compensation has got more attention. As a dynamic compensation equipment, active power filter has much larger advantages than other compensation methods. Compared with other kinds of APF(active power filter), this paper chose the cascaded APF to study and puts forward a design of cascaded APF based on DSP control, with special attention on harmonic detection and control strategy.The background, development and future prospect of APF, the classifications and topology structure of the active power filters are described in detail in the thesis. Analyses are made on the operational principle of the cascaded active power filter. The thesis studies the harmonic and reactive power current detection method. To overcome the disadvantage effects resulted from distorted supply voltage, a new harmonic and reactive currents detection method is presented. Shunt APF's and cascaded APF's control strategy are described in detail, SVPWM is adopted to control the compensatory current, and DC voltage is controlled effectively by the closed loop way.A design of control system selecting TMS320F28335 DSP as the control core and its hardware design and software flow are introduced in detail. A simulation model of APF system is established with MATLAB. The simulation and experiment results validate the method of reactive and harmonic current detection and control strategy in the dissertation, and also meet the design requirement of APF.