Hardware Design Of Active Power Filter Based On DSP

In recent years, current rectifiers, frequency converters, arc furnaces and other power electronic devices etc have been increasingly used in power network. With nonlinear, impactive, unbalanced characteristics, they generate lots of harmonics and cause distortion in power network current or voltage. Power networks are polluted by harmonics, which do harm to electrical equipments;cause devices superheat, generate vibration and noise. A more serious consequence is that devices are damaged. Harmonic pollution has been one of the nonnegligible problems in power supply systems and now catches people's eye.Passive filters and active power filters (APF) are the two primary approaches for eliminating harmonics. Active power filter is the equipment used to dynamically clearing up harmonic and compensating reactive power, and APF has a fine prospect. Control of APF is very important to affect active signal filter performance. Comparing with passive filters, APF have many advantages, which are not easily affected by system impedance and can be used to dynamically compensate harmonic. APF will play an important role in eliminating harmonics. Researches on APF are focused on main circuit structure forms (series-type, shunt-type, series- and shunt-type), harmonic current detecting approaches and control strategies to compensate current etc. Digital signal processor (DSP) has the characteristic that its processing the signal is very quickly, so it adapts to control the APF.This paper takes the three-phase parallel active power filter as the research object, and the principle of its work, its topology, main circuit form and PWM control strategy and so on have been made thorough discussion. TMS320F2812 DSP that TI Corporation launched to the market recently is used as the core processor, and the design principles of the core control board of APF, the sampling current signal board, the synchronized signal and the phase-lock circuit, the light-coupling isolation circuit as well as the inverter bridge circuit which is composed by the intelligent power module (IPM) have been stressed. And the test installation has been manufactured and system test has been carried on in the laboratory environment. The experimental result indicated that this kind of APF based on the TMS320F2812 DSP has the good compensating-characteristic.