Few days ago, GoHz made a 24V 2000W power inverter in home, sharing some design schematics and circuit diagrams.
Power inverter testing. The picture was taken in short-circuited.
Output waveform. The SPWM accuracy of EG8010 was not high enough waveform, so the inverter output was not good enough as pure sine wave. The dead zone time was a bit long (1uS), where the zero-crossing point did not look good, in order to ensure the safety of the tube, GoHz did not adjust it.
This was a full load test on the power inverter, two water heaters, about 2000 watt, the water was boiling completely. Maximum connected load was 3000 watt for approx 10 seconds, due to the DC power supply limitation (paralleling a large DC battery and two small batteries), GoHz did not continue test it. Adjust the inverter power limitation potentiometer, limit the maximum power at 2500 watt, (a little greater than 2500 watt), the power inverter works for less than two seconds before it turn off the output. Short circuit protection is also set about two seconds to turn off the output. Due to the EG8010 programming reason, the power inverter will continuous work after a few seconds if the power supply is not cut off. This power inverter has a good starting ability, it only takes about 1 second for two parallel 1000 watt solar lamps. This inverter is designed to power about 2200 watt, the headline of this paper is 2000 watt is because the DC power supply maximum output current is 100A, so GoHz tested it at 2000 watt, for more than 12 hours testing, it can work well at 2000 watt, there would be no problem for the actual load at 2500 watt.
This is the foreline tube D level waveform when the power inverter was in 2000w full load.
Expanding the foreline tube D level waveform when the inverter in 2000w full load.
This is the power inverter in no-load power consumption test.
It can be seen from two multimeter, no-load power consumption is 24.6 * 0.27 = 6.642W, no-load consumption is relatively low, it can be used for photovoltaic, car batteries and other new energy systems.
Forward toroidal transformer. Stacked two 65 * 35 * 25mm ferrite ring, primary 3T + 3T with 16 1mm wires, the secondary was used very fine multi-strand wire tangled wound of 42T, auxiliary power 3T.
Using 4 pairs ixfh80n10, 80A, 100V, 12.5 milliohms resistors. Rectifiers are 4 set MUR1560, two large electrolytic 450V470uF, 4 35V1000uF Japanese chemical capacitors for 24V DC input.
Backward power tube is 4 set FQA28N50, output inductor is sendust 52mm with 1.5mm enameled wire wrap 120T, inductance 1mH, capacitors are 2 set 4.7uF safety capacitors. Two high frequency arm FQL40N50, and two low frequency arm FQA50N50.
Short circuit test. This power inverter is sensitive in short circuit protection, after more than 100 times short circuit tests (power on short circuit, no-load short circuit, full load short circuit, loading short circuit), the power inverter is still work good. The output terminals of the inverter and the tweezers were scarred.
Here is the circuit section, get understanding the basics of this power inverter, DIY an inverter now.
Forward board DC-DC power circuit board, conventional push-pull. (Download PDF file)
Forward DC-DC circuit driver schematic. It has undervoltage, overvoltage, overcurrent protection, overcurrent protection is implemented by test tube drop. The circuit is conventional SG3525 + LM393. (Download PDF file)
Backward DC-AC schematic, using conventional circuit too, there is nothing new places, the unique is the additional high-voltage detection circuit, means when the DC voltage is higher than 240V DC, the auxiliary power is turned on, and the backward circuit is beginning to work. In debugging, add a function of turning off the SPWM drive circuit when the auxiliary power drops, to prevent the inverter bombing incidents when the auxiliary power supply drops but the DC voltage was still high, by adding this function, we can shut down the power inverter in short circuit. (Download PDF file)
SPWM driver board circuit, EG8010 + IR2110, to detect the voltage drop for short circuit protection. (Download PDF file)
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