一种新的带硬件互锁功能的变频器驱动电路

A New Inverter Drive Circuit with Hardware Interlock Function

IGBT驱动保护电路作为变频器主回路和控制回路之间的接口电路,设计好驱动保护电路对于变频器正常工作起着举足轻重的作用。传统的变频器驱动电路仅仅依靠软件设置的死区保护时间来避免出现同一相上下桥直通的现象,这种电路一旦软件出现跑飞的情况,则容易造成IGBT上下桥直通,炸毁逆变桥。介绍了一种全新的带硬件互锁功能的变频器驱动电路,这种新的驱动电路中变频器逆变桥驱动光耦的前端采用差分的PWM信号驱动,同一相桥臂上桥与下桥的驱动电路中的两只光耦的前端由同一组逻辑相反的差分的PWM信号驱动,从硬件上实现了逆变桥驱动电路的互锁功能,避免出现上下两个桥直通的现象,极大的提高了驱动电路的可靠性。

Insulated gate bipolar transistor （IGBT） drive protection circuit is taken as the interface circuit be- tween the inverter main circuit and the control circuit. It is very important for the inverter to design a good drive pro- tection circuit in normal operation. Traditional inverter drive circuits only rely on software to set the dead zone pro- tection time to avoid the phenomenon that the up bridge and down bridge of the same phase simultaneously turned. Through this circuit, once the software runs error, it is likely to cause the IGBT up bridge and down bridge simulta- neously turned and blows up the inverter. A new inverter drive circuit with hardware interlock function is de- scribed. In this new drive circuit, the inverter bridge drive opto-coupler is driven by a group of differential pulse width modulation （PWM） signal. The two opto-couplers for the up bridge and down bridge of the same phase bridge arm in the driving circuit are driven by the same group opposite logic differential PWM signal. The hardware inter- lock function of the inverse bridge drive circuit is realized to avoid the phenomenon of both the up and down bridge simultaneously turned and the reliability of the inverter drive circuit is improved greatly.