3phase to 1 phase conversion system

THREE-PHASE TO SINGLE-PHASE POWER-CONVERSION SYSTEM

ABSTRACT

A power-conversion system for converting three-phase power into single-phase power is proposed in this paper. The proposed three-phase to single-phase (3φ/1φ) power-conversion system comprises a power converter, a zero-sequence transformer set, and a filter capacitor. The output currents of the power converter are divided into two parts. One is a set of positive-sequence sinusoidal currents, whose phases are in phase with the voltages of the three-phase power source. The positive-sequence sinusoidal currents are employed to absorb a real power from the three-phase power source. In addition, the power converter can perform the functions of three-phase balance, low harmonic distortion, and unity power factor when the single-phase load is used. The other is a set of zero-sequence currents, which will pass through the zero-sequence transformer set and build a single-phase voltage with high power quality for the single-phase load. Since the proposed 3φ/1φ power-conversion system contains only one power converter, it has the advantages of simplifying both the power circuit and control circuit. A prototype is developed and tested to demonstrate the performance of the proposed 3φ/1φ power-conversion system. The experimental results show that the proposed system can achieve the expected performance.

CONCLUSION

Some industrial applications require you to feed a low-power dc/dc converter from a three-phase source and possibly to deal with line-toline voltages of 200 or 400V rms. Further, the neutral terminal of the ac source may be unavailable for connection, forcing you to use a line-to-line voltage link, which means a higher input voltage. Voltage faults can happen in one or two phases, and some applications require the power supply to keep working despite this problem. To handle these problems, you can use an uncontrolled rectifier and a capacitor to convert three-phase ac into a dc voltage, but this voltage may be higher than the maximum input voltage that a standard converter supports. It is difficult to find a dc/dc converter for these voltages, which are typically 564V dc or higher.