Study On The Drive And Protect Circuit Of Active Power Filters' Main Circuit

Active power filter(APF) is an advanced power electonic device,which can be used for compensing harmonics and reactive power. Compared with some conventional measures, active power filter has advantages of real time and accurate compensation. So active power filter has been studied widely and begin to industralise.One of the key techniques is the drive and protect circuit of main circuit in APF's application. Many companies and professors have studied this problem,but it hasn't been solved in practice. On the basis of study of IGBT's construction and characteristics, the requires to drive and protect circuit of active power filter is analyzed. A suit of drive and protect circuit of APF's main circuit is designed. A overcurrent protection method which can adjust the protect value according to protection require is developed. When overcurrent, IGBT is closed and delay circuit is started up. The PWM signal is closed off when the circuit is truely overcurrent. Otherwise,the drive voltage and the device get right. And the differernt characteristics of different close voltages are analyzed. At last, an experimental full bridge device is designed and some experiments are carried out. The results of the experiments show that the drive and protect circuit has excellent performances. The drive and protect circuits designed is feasible.