Design And Implementation Of Active Power Filter

While the power electronic devices are widely used today, the nonlinear of these devices have produced mass harmonic in network, make power system polluted and deduce the power factor markedly. They are harmful for electrical equipment and communication systems'stabilization. Traditional passive filters (LC filter) have lots of advantage such as simple structure, low cost, mature technology, but they also have some defect such as narrow frequency range, only eliminate few specified harmonic. Their filter characters are greatly affected by power network's resistance and frequency. They may be resonated by power network's resistance, which would magnify harmonic.The active power filter (APF) is developed rapidly these days, which is a dynamic harmonic depressed and reactive compensation equipment. The related research has become topic. In this thesis some topology and their advantage and disadvantage are given out. The thesis analyzed harmonic detection based on the instantaneous power theory, proportion control and feedforward control, SPWM and SVPWM modulation in detail. It gives a control system base on TMS320F2812 DSP from TI Inc. The system uses two closed loops scheme - voltage loop and current loop. Some function circuits are analyzing in detail, such as power supply, voltage and current detection, soft start, IGBT driving circuit and hold capacitor. The software is modular designed. Every module and their relation are introduced. The experiments show that this system can depress harmonic well.