May i check with you all, anyone knows how to design a dead time control circuit that can be used to provide two square wave signals to the half bridge IGBT inverter. It is the best that the two signals can have a dead time of 1.5 - 2 micro seconds. Please kindly assist
Hi,
Which controller are you using to generate the pulses? That controller should have option for generating deadtime, eg. SG3525 can be programmed to provide deadtime by using a resistor between pins 5(CT) and 7(RD). Or you could use a driver with programmable deadtime selection, eg IR21844/IR21834 can be programmed to provide deadtime between 0.4 to 5us. IR2183/IR2184 have internally set fixed 500ns deadtime providing circuitry.
Is there any other way to increase the dead time to 1.5 to 2 microseconds. Currently i am using the IR2111 with 500ns time delay, but i am also unable to get to 500ns, i am also unsure y is it so?
no i am using the International Rectifier IR2111, it is somewhat similar to what you have intro me just now for IR2183/IR2184. Just want to ask another question, because i am working on a single phase shunt active filter, can the IR21844/IR21834 withstand high power switching for the IGBT? Any methods can help me resolve this problem to obtain a dead time of 1.5 to 2microseconds?
Hi,
IR2111 is the driver. It has input for pulse. Where does that pulse come from? IR21844 can withstand high power, depending on how much drive current you need.
The signal comes from the matlab, but it is a open loop ref signal, because due to my limited knowledge in control i wasn't able to design such controller. The open loop ref signal frm matlab is output from dSPACE and using a comparator circuit, i used a triangular carrier signal of 7 - 12khz, and compared with my ref signal to obtain the PWM square wave signal.
Hi,
Can't you have the deadtime generated by MATLAB?
Otherwise, you should use a driver with deadtime control as I suggested above to extend the deadtime to above 1us. If it's okay with you, IR2111 has an internally set 650ns deadtime.
There is an analogue solution also, use asymmetric turn-on/turn-off gate resistance, by adding a diode+resistor in parallel with the present gate resistor.
no i am using the International Rectifier IR2111, it is somewhat similar to what you have intro me just now for IR2183/IR2184. Just want to ask another question, because i am working on a single phase shunt active filter, can the IR21844/IR21834 withstand high power switching for the IGBT? Any methods can help me resolve this problem to obtain a dead time of 1.5 to 2microseconds?
Why you need more than 500nsec dead time, if your mosfets has the switching capability at this speed than there should be no problem. Also i have used IR2109 and IR2184 IC in Single phase Inverter project both are working fine while the output curent of ir2184 is higher than ir2109 but both have same functionality but different pin configuration, if you need the reference circuit diagram then i will provide you.
Deadtime control means to manually control or adjust the deadtime. Deadtime is a small delay given between two drive signals during which time both the signals are (usually) low (logic "0"). This avoids the two driven devices - MOSFETs, IGBTs, etc. - from being turned on at the same time for a small amount of time (this event is called cross-conduction). So, deadtime is provided to avoid cross-conduction.