EGS002 inverter project help

I started a Pure Sine Wave inverter project which I am to use egs002 for this purpose. I have followed the datasheet carefully. I savaged a transformer from an old ups, the transformer is 15-0-15/220v which is meant for a 24vDC 1.2kv ups. I rewind this transformer to 0-7.5/220v to use for my egs002 inverter which I believe it should give me at least 500watt on 12v system.

For a test, I used 1 fet per bridge, making a total of 4 fets, I used irf3205 and 4.7ohm resistor with 1N4148 diode at each gate, with 10k resistor from each gate-source as stated in d datasheet. I believe this bridge should give me at least 100watt power.

I connected the Ho1, ho2, Lo1, Lo2, vs1 and vs2 to their respective pins on d egs002 board, IFB is grounded and VFB is connected to an 12v additional widing of d transformer which is rectified using 4 1N4007 diodes and adjusted with a 10k variable resistor.

12v and 5v were connected to their respective pins on the egs002 board. FanCtl, TFB were left open (not connected)

I powered my circuit and connected my scope, it worked fine, I adjusted 10k pot from VFB, to get 200v ac output which worked fine. But here is the problem

I tried to connect a 20watt load for a test, immediately I connect it, egs002 will shutdown and light blinks 4 times which means undervoltage protection (as stated in datasheet). But if no load is connected, the circuit works fine and IC doesn't shutdown.

Please help me. Why is egs002 shutting down when load is connected? The load is just a 20watt light bulb

Hi,

Why don't you simply show your schematic?

Klaus

https://www.thebackshed.com/forum/uploads/Tinker/2016-04-09_135959_inverter.gif

That is the schematic I am using

Hi,

This circuit can't work, because the gates are not driven.
Additionally you talk about 1N4148, which are small current signal diodes, wheras the schematic shows fast 1A schottky diodes.

Thus I assume this is neither "your" circuit nor is the schematic complete.

Klaus

Added:
Without consistant and complete informations about "your" circuit it's a waste of time, not only for us, but for you, too.

"This circuit can't work, because the gates are not driven."
The gates are driven by the signal coming from Ho1, Ho2, Lo1 and Lo2 of the EGS002 SPWM driver IC

The 1N4148 diode I'm talking about is the reverse diode used at d gates of the FETs, it is a fast recovery diode which is best for high frequency operation. Mosfet gates doesn't require high current to work and meanwhile, it is a reverse diode, so, I think the diode can do just fine

EGS002 is the driver board, the SPWM ASIC is SG8010.

The SG8010 datasheet specifies the criterion for undervoltage lockout, you need to measure why your circuit can't maintain the output voltage with just 20W load.

How do I check? What do I do? Pls help

E.g. measuring with an oscilloscope.

Hi,

The 1N4148 diode I'm talking about is the reverse diode used at d gates of the FETs, it is a fast recovery diode which is best for high frequency operation. Mosfet gates doesn't require high current to work and meanwhile, it is a reverse diode, so, I think the diode can do just fine

Click to expand...

You surely know, that the driver is able to sink/source up to 2A. And this high current is necessary to fastly discharge the gate via the diode.
It is correct, that the average gate current is low, but there are high peak currents, and those peak current are important for fast switching.
Do you know that the voltage drop across the 1N4148 is about 3 times as big as with the schottky diode?

This fast switching may easily cause ringing (or malfunction) with a non appropriate PCB layout.
It's on you whether we are able to validate your PCB layout or not.


Klaus