Hello everyone, I am working in a solar project where I have tested the Boost converter with the PV Input. I have conducted the test around 5-10 minutes. When I switch off the PV and check the status of diode and IGBT it is extremely heated eventhough it is connected with the heatsink. Therefore, I need some suggestions on how to run the system for a long time.
what is the onstate resistance of the igbt you employed,you can consider sycnchronous rectifiers instead of diodes if using for rectifying as they have conduction losses.The basic reason for heating is the inefficiency of the converter,if you design a 10kw converter with 90% efficiency then 1kw of energy is going to get dissipated as heat so efficiency of the circuit is the whole pivot for addressing heat issues.
did you used thermal heat sink compound paste? it will give some improvement
I agree with the comments above.
In addition, if you are using natural convection for cooling, make sure that air can flow freely over the fins (normally upwards).
Heat sink compound is essential and the device also have to be tightened down firmly to ensure good conductivity between the device and the heat sink.
In addition to use thermal heat sink compound paste paint the heat sink with black color, which increases the heat absorption rate.
You should properly choose a heatsink depending on dissipated power on your IGBTs and diodes. I also suppose, that thermal paste can help.
Your heatsink is characterized by its thermal resistance, let call it Rca (as it will impose a thermal resistance from the Case of your device to the Ambient).
In order to choose the heatsink, you need to calculate the dissipated power on the device, Pd.
From the device's datasheet, you take the maximum Tj (junction temperature), and the junction to case thermal resistance (Rjc). Look at the attached picture thermal_info.png
1. Estimate a maximum temperature difference from junction to ambient (i.e Ta=25°C): DT=Tj_max - Ta.
2. DT>Pd*(Rjc+Rca). this lead you to Rca
hello
first of all you should calculate your loss, I mean switching nd conduction loss which the sum of them is the heat that is being conducted so this time by ambient tempreture and junction temreture difference you can calcualte the thermal resistance finally subtract the junction to case resistance and case to headsink resistance then what remains is headsink to air resistance
by this resisance you can choose the proper headsink
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