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For lower breakdown voltages, a power MOSFET is clearly the device to go for, in view of its higher efficiency, higher commutation speed and lower price.
Where should the line be drawn, upwards of which IGBTs take over as the preferable solution? What are the relevant decision criteria?
user1975053
MOSFET versus IGBT: round 1. The MOSFET or IGBT question is a recurring one. We all have faced this question once. Knowing which type of FET to go for. And the question is still going-on. You can look for the web, and you find an IGBT manufacturer’s e-book about how IGBT’s are such a good solutions for so many applications. The IGBT combines the simple gate-drive characteristics found in the MOSFET with the high-current and low-saturation-voltage capability of a bipolar transistor. It does this by using an isolated gate field effect transistor for the control input, and a bipolar power transistor as a switch. The IGBT is specially designed to turn on and off rapidly.
user1975053user1975053
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$begingroup$The main criteria in choosing either IGBT or MOSFET are voltage rating, power losses (efficiency of the whole system) and of course the cost of the whole system. Choosing one over other may impact not only losses in the transistors but also the weight and cost of cooling, size of the complete product and also reliability so sometimes e.g. a weight constrain may force you to use MOSFET instead of IGBT.
If you look at this graph, you will see different areas, where each type of switch are typically used:
Choosing a particular device type depends on specific application and its requirements.
MOSFETs dominate in high frequency and low current applications because they can switch extremely fast and act as resistance when on.
Fast switching means they are used when the device has to be small as when you increase switching frequency you can reduce the size of passive filters.
The conduction losses are proportional to the square of drain current and therefore you cannot pass huge current through the structure.
They also have limited breakdown voltage and are typically used up to 600V.
IGBTs have higher breakdown voltage and conduction losses are approximately equal to Vf*Ic therefore you can use them in high current applications. They have limited switching speed therefore they are typically used in industrial applications where low switching frequency is not a problem (acoustical noise).
Szymon BęczkowskiSzymon Bęczkowski
$endgroup$$begingroup$This question is really difficult to give a firm answer to. There are some jobs FETs simply can't do, and some jobs IGBTs simply can't do. If you're in a domain where both are possible solutions, you look at cost, including footprint and thermal management, and pick the cheaper one. In many cases (though not all), this will be a FET. But in a lot of cases, the decision is made for you simply by the application.
Stephen CollingsStephen Collings
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$begingroup$I simulated three phase rectifier using a thyristor like so:
I get the expected result. But if I change the thyristors to IGBTs as shown below, it does not work.
Why do these two circuits behave differently?
Leah CollinsLeah Collins
$endgroup$2 Answers
$begingroup$In the scr rectifier, you have given individual gate pulses viz PG1,PG2,PG3 etc. But in the IGBT, YOU HAVE given a common have signal to ask the 6 IGBTs. It will lead to a short circuit.
jitendra pbjitendra pb
$endgroup$$begingroup$IGBTs and SCRs behave completely differently.
SCRs block cathode-to-anode, and conduct anode-to-cathode when gated and forward biased.
IGBTs with antiparallel diodes conduct emitter to collector, block collector to emitter unless gated, and conduct collector to emitter when gated.
![Ipm Vs Igbt Ipm Vs Igbt](/uploads/1/2/5/6/125633785/441475054.jpg)
In your case, you're turning on the upper and lower IGBTs at the same time. This causes a short circuit across the DC bus, which will break something. It will definitely not rectify. If you were not turning on the IGBTs, the circuit would behave like a normal diode rectifier. SCRs don't have that problem, because even when gated on they don't reverse-conduct. (It's still not a great idea to gate them on when heavily reverse-biased though.)
I'd give you other recommendations, if you could describe what goal you are trying to achieve.
Stephen CollingsStephen Collings
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