Summary of switched reluctance motor suspension drive ir2128

Use IR2128 A summary of the use of the switched reluctance motor ：

advantage ： The main reason is that several groups of drivers can share one power supply , It greatly simplifies the design of switching power supply .

After constant testing , Also found several shortcomings , The disadvantages also stem from the principle of floating , That is, when the lower tube is conducting , The driving capacitor of the upper tube will be charged , To drive the upper tube IGBT. That is to say, the upper tube IGBT The necessary condition for conduction is that the pipe is lowered IGBT Must have been turned on . This feature has several disadvantages when used in switched reluctance drive .

1, The upper pipe is straight through , When chopping down the pipe , This is not the zero pressure freewheeling of the upper pipe , Instead, the up and down switches on and off at the same time , That is, the upper tube is not really straight through , It turns on and off at the same time as the lower pipe , Perform chopping . This leads to a large current hysteresis , To reduce the current hysteresis , Make the current smooth , Must increase PWM The frequency of , This will lead to IGBT The switching loss will be greatly increased .

2, Large current hysteresis , The current is not flat , Uneven torque , Increase motor noise and vibration .

3, In order to reduce the heat loss of the upper and lower freewheeling diodes , Generally, the upper and lower levels take turns chopping . If the upper pipe passes through , Lower tube chopper , Startup time ,PWM The duty cycle of is very small , At this time, it is like the first time 1 Point to , In fact, the upper and lower levels cut waves at the same time , Cause negative pressure freewheeling ,PWM The duty cycle is very small , The current builds up very little , During negative pressure freewheeling , The current returns to zero , It's hard to really build .PWM When the duty cycle is large , Electric current will be established . At the beginning of start-up , Motor does not operate , When the given value is very large , Sudden motor action , And it rises to a very high speed .

In view of this , It is only possible to use down pipe straight through at start-up , The way of chopping the upper tube . But in normal operation , Large current hysteresis leads to uneven torque , Increase vibration and noise . therefore , It is better to choose an independent drive switched reluctance motor .