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cts_casemod · 08-09-2015, 12:05 PM

According to the simulations a frequency of 40KHz produces good results, with a current swing of 6A. This can be easily achieved by most fast IGBT's.

The Plots below are for an output power of 5KW and input voltage of 248VAC.

Here, I implemented the PFC pre-converter as a constant current source. There's no voltage loop, for simplicity, although the real thing has one.

With F= 40KHz, Max duty = 97% and a current limit of 26A, the inductor works in CCM for most of the time.

Blue Plot = Inductor current
Green Plot = battery current (Follows input voltage)
Red plot = Battery voltage (Rbat = 0.5Ohm)

Here a further detail during the AC supply peak

During the AC supply zero crossing. There's a blanking period of 0.7ms after each zero crossing. There's also a bit of noise (I didn't smooth the input signal for the simulation to run faster)

Also a test at 120VAC. The inductor current is discontinuous and peaks at 12.5A, however the output current is only 2.1Apeak or 1.5ARMS = 660W. This is to show how the peak currents and hence losses double when the converter operates in DCM.

This one is for 300V DC supply: 18A Average input current (22A peak), with an output current of 11.7A (5.15KW). This is what can be expected for the inverter boost converter, although with higher currents, which should allow a lower inductance value for the inductor.

08-09-2015, 12:05 PM	#11 (permalink)
cts_casemod EcoModding Apprentice Join Date: Nov 2012 Location: East Midlands Posts: 180 Thanks: 13 Thanked 81 Times in 52 Posts	According to the simulations a frequency of 40KHz produces good results, with a current swing of 6A. This can be easily achieved by most fast IGBT's. The Plots below are for an output power of 5KW and input voltage of 248VAC. Here, I implemented the PFC pre-converter as a constant current source. There's no voltage loop, for simplicity, although the real thing has one. With F= 40KHz, Max duty = 97% and a current limit of 26A, the inductor works in CCM for most of the time. Blue Plot = Inductor current Green Plot = battery current (Follows input voltage) Red plot = Battery voltage (Rbat = 0.5Ohm) Here a further detail during the AC supply peak During the AC supply zero crossing. There's a blanking period of 0.7ms after each zero crossing. There's also a bit of noise (I didn't smooth the input signal for the simulation to run faster) Also a test at 120VAC. The inductor current is discontinuous and peaks at 12.5A, however the output current is only 2.1Apeak or 1.5ARMS = 660W. This is to show how the peak currents and hence losses double when the converter operates in DCM. This one is for 300V DC supply: 18A Average input current (22A peak), with an output current of 11.7A (5.15KW). This is what can be expected for the inverter boost converter, although with higher currents, which should allow a lower inductance value for the inductor.