Top power electronics threads on EDAboard.com – December

High voltage input cascaded input converter – We have to do a non-isolated SMPS for vin=120v to 400v, and vout = 100v, pout=300w. There is a “known” way to do this involving two cascaded synchronous buck stages. Do you know more detail of this “known” method? Read more

Designing a charge controller for hybrid system – I want to design a hybrid solar with wind charge controller charging at 150Ah SMPS. How do i start with this any inputs? Read more

Disastrous problem intrinsic to DC restored transformer gate drives –  When the converter is suddenly no-loaded from full load of a DC restored transformer FET gate drive, the duty cycle obviously goes fairly quickly to zero. Ater the duty cycle has finally gone to zero, the FET gate voltage of the high side FET lingers high for many switching periods…….BOOM! As far as we can see, this can only be stopped by very heavy resistive damping…damping which is far too heavy for a transformer gate drive. So what’s the answer?  Read more

Push-pull start-up issue – I have a problem with the high and low ac mains voltage cut off circuit. The high voltage part is working but the low voltage part isn’t working good. If I set the low voltage cut off point as 190, for example, the output starts oscillating when the voltage is less than 190. What could be the reason for that? Read more

Why does output oscillate a low voltage? – The output from the high and low voltage cut off circuit is fed to the RD7 of the pic as an input which switch off and on its output(RD5) according to the RD7 input value.Under normal condition RD7 would be 1 and under low or high voltage conditions RD7 would be 0. Read more

SMPS: startup transformer inrush current destroying MOSFET – I made a half bridge offline SMPS and it has worked with various different switching MOSTFETs. I started with a transformer and they worked with a moderate output load. Then I connected a second transformer which is almost identical to the first one and also has a rectifier and smoothing, as well as a small load attached. I attempted to start this configuration and the MOSFET went short and died. How powerful the devices should be for me to choose, since the inrush startup current of any transformer is at least seven times the normal idle current, especially if the secondary has a load attached to it? Read more

1KW flyback converter for battery charging – Can you please suggest the techniques for voltage and current control of battery (48 V, 120Ah) at load, using a 360 to 500 V DC input and 57 V, 12 A output? Read more

Power supply for GSM-based project – We are developing a GSM-based project and require a charger for the battery. Can you suggest some regulators  available in India for minimum quantity 10 to 50)? Read more

IGBT or FET module for 7kw grid tie inverter? Are there any of IGBT modules (or FET modules) for a 7kw grid tied inverter which we want to operate at 30khz? It is for 7kw, and 230VAC mains only. We will have four FETs (or IGBTs) Read more

Gate drive transformer problem…FETS getting killed – The attached high-side FET driver circuit is blowing the FET up repeatedly in the lab. The circuit is for a high-side FET of a Buck converter, but the FETs are blowing up even when the FET is pulsed without there being any input voltage to the buck converter. Read more