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Half bridge rectifier using power mosfet

Hi

 

I am currently doing a project which requires a half bridge rectifier using IPD60R385CP power mosfet. This mosfet is driven by a TC4424AVOA 3A dual High-speed mosfet driver. The pulse signal is generated by a function generator with 200kHz, 50% duty cycle and 100ns rise/fall time. 

 

Everything is working fine under a 12V DC power supply (V1), connected to the drain of the power mosfet (U2). However, when I change the power supply to 380VDC, there will be a convergence error prompting me during simulation. My project requires high input voltage of about 380V to 400V.

 

I am using Multisim 14 Pro Edition.
Below are my attached files of my schematic circuit and also the datasheet of the power mosfet and mosfet driver. Can anyone help me with this problem?

Screenshot 2016-01-08 17.31.14.png

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Message 1 of 11
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hello Ivan, .

it seems to me  the problem is not MS, the problem is your design.

 

when your Vcc is 12v everything is OK.

But after you increased voltage above 12 v, top part of module (   U1a, U2 ) stops working.

 

your have to use floating driver for top part.

 

I'd recommend to use signal transformers for both  - top and bottom parts.
 


with hope it helps

 

thanks

 

Michael

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Message 2 of 11
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 Hi Michael

 

Thanks for your advice! It did help me with the circuit.

 

I have researched and found out that IR2110 is capable to support a high voltage rail of up to 500V, which solve the problem of my 380V input supply. However, the other problem i faced is the output voltage waveform of the half bridge is not square wave. Is there any solution to make it square wave?

 

I attached the updated circuit file and also the jpeg file on the waveform. The red line is the voltage waveform, while the blue line is the current waveform.

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Message 3 of 11
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Hello Ivan , thanks for response.

 

 

it happens because of nature of your load. it is LC filter actually.

 

try plain resistor as a load and you should see square wave.

 

actually I am messing up with this kind of electronics as my job.

 

I have tried to use ICs like IR2110 - they do the job but IMHO - signal transformers are much more reliable.


with hope it helps
good luck
thanks a lot
Michael

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Thanks michael! I will try it and let you know:)

Cheers
Ivan
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Message 5 of 11
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Hi michael! 

 

Thanks for the advice previously:) Just another problem here, I am actually currently working on the LLC resonant DC-DC converter, not sure if you have heard this before. It requires the resonant capacitor and inductor & also the magnetising inductor for the resonant tank transformer. However, after I have connected the full wave rectifier at the secondary side of the transformer, the voltage dips to 2.6V, which is not the desired value. The desired value is 12V & 17A, but I couldn't solve it. In addition, the waveform of the output voltage shown is a straight line, which is correct, but the current waveform is not. Any solutions to that?

 

Note: The switches are for presentation and explanation purpose. Attached is the updated simulation file.

 

Thanks

Ivan

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Message 6 of 11
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You said nothing about switching frequency, but with those 10K gate pulldowns you will get hughe cross-conduction currents, more than the transistors can handle.

A more sensible value would be 1K, 100R, or even 10R. Put an amperemeter in the supply and see the difference !

 

 I suggest you remove the diodes (and the 10K gate pulldown), and drive the gate directly, via a 2 - 10R resistor.

As others have mentioned you need a floating hi-side driver, otherwise you'll blow the hi-side transistor with excessive gate voltage.

And note that in order to fully turn on this transistor it's gate must be pulled some 8V above the drainvoltage.... many hi-side drivers have bootstrap circuitry that will take care of that.

 

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Hi RR

My switching frequency is 200kHz.
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I just checked the transistor's datasheet: Ciss = 800pF... not too bad, but at those frequencies you need to drive the transistor really hard in order to fully charge that capacitance in "no time", and discharge it fully in time before the other transistor is switched on.

 

When driven correctly you should see a nearly perfect rail-to-rail squarewave at the common node between the transistors, even at 200Khz.

In your circuit I'd expect to see a sine-like or maybe a sawtooth waveform of limited amplutude.

 

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Message 9 of 11
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Hi RR

Much thanks for your advice!:) I am really a beginner in these kind of circuitry stuff, thanks for the guidance! I will try it out:)

Ivan
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