Hi, I have been working on a duracell 3000 w inverter model drinv3000, long story short, my dad used it with power tools and now it does not work properly, he measured the voltage, and it delivers 104V AC instead of 115.
I already checked almost every component on the board (desoldering them and testing), and I haven’t found any problems, some of the components just were a little off standard value but I replaced them.
So far, I have an idea of where the problem is. The inverter consist of three main parts: a circuit that uses 18 mosfets and several transformers to increase the voltage of the battery (12V), then, that increased voltage is rectified with 3: FMS MUR1620CA and 3: FMS MUR1620CT ultra-fast diodes, these two parts deliver at the end 160V DC, and lastly (the part that I think is going wrong) is where those 160V are converted to 115VAC,I think that because according to the formula of VRMS, VRMS= Vpk/ √ 2 in this case Vpk = 160V so VRMS=113.13V (but I’m having 104VAC). This last part consists of 8 N-Channel mosfets that simulate a 60Hz sine wave.
I purchased an inexpensive oscilloscope to check the output signal and I noticed something is off, the output signal instead of being perfectly square, has a lot of peaks and look a bit unstable/erratic, I compared it with another Inverter and the other one look just fine.
I also checked the two signals from the microcontroller that trigger the gates on the mosfets and they look fine, I reverse engineered the diagram of this part of the circuit so you can see it (I already checked every component here too) What do you think it’s causing the peaks in the output signal?, Do you think even though the components I checked work fine, they misbehave at fast switching?
(attached circuit) two of this exact same circuits generate the AC output, they just have an out of phase signal input from the microcontroller.
Heres a video where you could see the output signal and the spikes I talk about
I already checked almost every component on the board (desoldering them and testing), and I haven’t found any problems, some of the components just were a little off standard value but I replaced them.
So far, I have an idea of where the problem is. The inverter consist of three main parts: a circuit that uses 18 mosfets and several transformers to increase the voltage of the battery (12V), then, that increased voltage is rectified with 3: FMS MUR1620CA and 3: FMS MUR1620CT ultra-fast diodes, these two parts deliver at the end 160V DC, and lastly (the part that I think is going wrong) is where those 160V are converted to 115VAC,I think that because according to the formula of VRMS, VRMS= Vpk/ √ 2 in this case Vpk = 160V so VRMS=113.13V (but I’m having 104VAC). This last part consists of 8 N-Channel mosfets that simulate a 60Hz sine wave.
I purchased an inexpensive oscilloscope to check the output signal and I noticed something is off, the output signal instead of being perfectly square, has a lot of peaks and look a bit unstable/erratic, I compared it with another Inverter and the other one look just fine.
I also checked the two signals from the microcontroller that trigger the gates on the mosfets and they look fine, I reverse engineered the diagram of this part of the circuit so you can see it (I already checked every component here too) What do you think it’s causing the peaks in the output signal?, Do you think even though the components I checked work fine, they misbehave at fast switching?
(attached circuit) two of this exact same circuits generate the AC output, they just have an out of phase signal input from the microcontroller.
Heres a video where you could see the output signal and the spikes I talk about
