High Current PWM

[JMBacker]

Hello Everyone,

I'm new to your forum, and by no means an electronics expert. I have a basic knowledge, that's about all.

I'm a general engineer for a company dealing with used automotive parts, and I have been tasked with developing a method to test solenoids in transmissions. These solenoids operate on a 12 VDC Pulse Width Modulated signal. Some of the solenoids will be as low as 1 Ohm, so the current can be fairly high. I would like to design the tester for around 30 amps to ensure we can test anything that might come up in the future.

I need to produce this 12 VDC PWM signal. I need to be able to set the frequency before the test begins, and I need to be able to control Pulse Width during the test. The tester will be completely automated, programmed with LabVIEW, and I need to control the PWM signal from the LabVIEW program.

What I need from you guys is help finding the right hardware for this job. There are several PWM boards available through National Instruments, but they are all lower current. I would like something that is built and ready to use, no assembly necessary.

Thanks for the help.

 

[Ubergeek63]

your best best for what you want to do is to use the national instrument module and add a current boost to the output... minor assembly but you have all the support on the instrumentation end.

 

[crutschow]

You should be able to use one of these high speed solid-state relays, which are good to 15kHz, to boost the current from the National Instrument PWM module. It should be quite simple to connect the two together.

Note: Be sure you add a diode across the load (cathode to the positive side) to suppress the inductive transients of the solenoid, which likely will otherwise blow the relay. Since the transients are short, a 10A or larger diode should be sufficient for this. Edit: Noticed that Power-IO also sells some recommended diodes for transient suppression, so those are obviously good for this purpose.

 

[JMBacker]

Looks like those will do the trick. Thanks for the link.