AN4070
Experimental test results
Doc ID 022934 Rev 1
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Experimental test results
The typical voltage and current waveforms of both the DC-DC and DC-AC converter are
shown in this section. In particular,
Figure 22
shows the characteristic waveforms of the DC-
DC converter MOSFETs, namely the drain to source MOSFET current (green track) and
voltage (purple track).
Figure 22.
DC-DC converter MOSFET current (green) and drain to source voltage
(purple) @250 W
The transformer leakage inductance is the cause of the peak on the drain to source voltage
at turn-off. This peak has a maximum value of 89 V, which was recorded when the
microinverter was operating at 250 W of output power with an input voltage of 30 V.
Figure 23
shows the current flowing through each of the two input inductors and the effect of
current ripple cancellation that the interleaving has on the converter input current (blue
track) when the system is operating at 30 V input and 250 W output power.
The HF transformer main waveforms are reported in
Figure 24
, where the purple track is the
transformer input voltage, the blue track is the transformer secondary voltage and the yellow
track is the primary winding current. It is worth noting that the secondary voltage is only half
of the total output voltage due to the presence of a voltage doubler connected downstream
of the secondary winding. The current and voltage waveforms across one of the two rectifier
diodes are shown in
Figure 25
.
