| An example of a UPS output circuit
In this article, we are going to investigate a UPS output circuit. |
| The circuit below shows a practical example of a three phase UPS output circuit designed to generate a voltage of 400 VL-L. The output is 1: 2 conversion ratio, so the output of the inverter is VL-L200 which is equivalent to VL-N (200 / (√3)) 115 and approximately “VP-P (2 115 √ 2) 325”. The output voltage (peak to peak) cannot produce more than the dc busbar voltage, if the dc busbar falls below this minimum value (V325), the peak output waveform will definitely be eliminated.
In this example, a delta-star transistor is used to generate the insulation, and the secondary coil zero point is practically connected to the bypass ground line to create a common communication point between the two power sources. The output filter works in harmony with the output transistor to produce a complete sinusoidal voltage by eliminating the harmonic from the output waveform. |
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