| The wide use of power electronic equipment makes harmonic problem deteriorated increasingly. Harmonic becomes the primary factor influencing power quality. As an effective means of harmonic restraint, active power filtering (APF) technique becomes the research focus of scientific and technological personnel.Nowadays, APF is mainly used for the low voltage network and the research of APF with high voltage and large capacity are barely commenced, which focused on the basic topology, detection of the current distortion and control scheme, but less on soft-switching and snubber circuit.The topology and control scheme of multi-level converter were introduced firstly in this thesis. Then the soft-switch for multi-level converter was lucubrated and a novel zero-current-turn off circuit for three phases three-level inverter was brought out. We proved its ability of soft-switch theoretically by analyze its switch process and authenticated the feasibility of the circuit by simulation.Power quality harnessed synthetically equipment was developed combine with the item of equipment researching for harmonic, negative sequence and reactive power harnessed synthetically. The circuit design of this equipment was introduced from three aspects containing major loop, control loop and detecting loop. And the hardware and software design of a digital control device and especially the program and function of an operating interface were lucubrated in this thesis.The experiment part of the thesis introduces the experiment result of testing main function of the control device, which testified the feasibility of the hardware and software design. Additionally, we made use of the APF equipment carried out some experiments include compensation capability, boosting control of DC side, control scheme of APF as well as join the system lasting out 24 hours, which proved the equipment can almost compensate harmonics under 25 times of power system. |
PDF Full Text Request