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i am designing DC to AC converter. The first phase of the converter is a boost converter that will boost voltage from a 12 V battery into 30 V. Then the 30 V is fed to an inverter that will invert 30 V into 30 Vpk-pk AC signal. The ultimate output voltage of the system was required to be 230 Vrms. So i included a transformer rated 20/230V rms. When i simulate the cascade of a boost and inverter with a load, on simulations it works fine. then I designed and built and tested my boost independently and it worked properly. I also designed and built the inverter, it also worked fine. But when i test the cascade of both subsystems with a load of 77 W( overall system is rated at 120 W). the problem i am encountering is that when the load of 77 W is connected on my system the systems output voltage drops to 135 Vrms, i am not sure what might be the problem because on simulation it works fine and i a getting 230Vrms?

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    \$\begingroup\$ in the simulation it works fine but not in practice A simulation uses a model of reality. All models are just that, models and models are a simplification of reality. So what you have encountered is some effect which is not modeled but is present in the real world. I name a few these: series resistance of wires, PCB, connectors. Saturation of the transformer. Higher than simulated on resistance of a transistor . The engineer's approach now is to measure and simulate to see where the differences are. \$\endgroup\$ – Bimpelrekkie Oct 27 '16 at 20:26
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    \$\begingroup\$ @FakeMoustache that should be an answer, not a comment. OP's question (there is none, but what jabu means to ask) is: What is the difference between simulation and reality? and you answer that. \$\endgroup\$ – Marcus Müller Oct 27 '16 at 20:52
  • \$\begingroup\$ I don't know your inverter design, but it is likely that the inverter is drawing current at a low duty cycle. Especially for the 50/100Hz time frame, the power requirement during the phase when the inverter is actively drawing power could be significantly higher than the average power. So it would not be surprising that the converter that feeds the inverter would need to have a much higher power ratings. \$\endgroup\$ – rioraxe Oct 28 '16 at 0:27
  • \$\begingroup\$ @ fakeMoustache i get your point, but i am just surprised could those factors have so much effect on my output voltage, it is almost half of what is expected. \$\endgroup\$ – jabu Oct 28 '16 at 1:05
  • \$\begingroup\$ @rioraxe i get your point, does that mean if i could reduce my load to a lower power(e.g 40W) that will result in an increase of output voltage. \$\endgroup\$ – jabu Oct 28 '16 at 1:08
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in the simulation it works fine but not in practice

A simulation uses a (simplified) model of reality. All models are just that, models and models are a simplification of reality. So what you have encountered is some effect which is not modeled but is present in the real world.

Let me name a few of these effects which might not be modelled:

  • series resistance of wires, PCB, connectors.
  • Saturation of the transformer.
  • Higher than simulated on resistance of a transistor .

The engineer's approach now is to measure and simulate to see where the differences are

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