Can any one help ?? PWM converters

[A.A.K]

Which NI Compact Rio Module can help me controlling grid sided Three level PWM Converters with switching frequency 20KHz at least.

As far as I know Three level converters have 12 switches , so each converter would need 12 inputs if i am not wrong. I just want to generate PWM signals to control my grid side and front end converters in real time. 
I am actually trying to build a grid emulator for generating disturbed voltages to analyse grid connected devices. 

Thanks 

[Blayne_K]

Hello A.A.K,

To better answer your question, could you tell me a little bit more about the control signal that is required for the level PWM Converters (minimum Current, threshold Voltage etc), or perhaps could you reference a manual of the converter that you will be using in your system design. 

Thanks,

Blayne Kettlewell

[veichch]

PWM is the pulse width module is about the frequency direction and circuit direction. actually I can't explan it so excatly but you can refer this below http://www.veichi.org/variable-frequency-drives.html

[riplakish]

Hi A.A.K.

If you are referring to a three-level (-Vdc, 0, +Vdc) single-phase inverter (or h-bridge), you actually only need 4 switches, as shown in this diagram.  If you mean 3-phase, then you'll need a third switching leg, adding 2 more switches to the circuit.  Most PWM inverter switching schemes require that the top and bottom switch in each leg be complementary, meaning that you can actually reduce the number of unique digital signals to 2 PWMs which are then complemented in hardware using a synchronous gate driver like this one.

So whether you're using 2 or 4 digital PWM outputs, you'll need a digital module which can update fast enough for your switching frequency.  What kind of NI hardware are you planning on using?  I use a cRIO in FPGA mode and I've found the NI 9401 very affordable and suitable for inverter applications.