Practicability Research on “Phase-Hopping” AC–AC Frequency Conversion Technology

Abstract

The ''Phase-Hopping'' AC-AC frequency conversion technology proposed on the basis of traditional technology has the advantages of no circulating current, no dead zone and output frequency that can be improved to close to the power frequency. However, the research on this technology at present is still limited to the low voltage level, and problems such as low system capacity and high harmonic wave still exist, which cannot be applied in practice. To this end, a three-phase series-connected six-fold ''phasehopping'' AC-AC frequency conversion main circuit is designed on the basis of traditional series-connected multiple technology, which addresses the voltage withstanding problem of thyristors, reduces harmonic content and enlarges system capacity, and the circuit is simulated by MATLAB. Furthermore, a singlephase series-connected six-fold ''phase-hopping'' AC-AC frequency conversion experiment platform is set up, which includes the key main circuit and the trigger circuit and improves its synchronous detection circuit. The simulation and experimental results are consistent with the theoretical analysis. In view of the technical transformation of ''phase-hopping'' AC-AC frequency conversion of common high-voltage and large-capacity pump station motors, the main circuit is designed, the model selection of thyristor is conducted, and the cost estimation of frequency converter is carried out. The analysis shows that the system has a high cost performance, thus it can be seen that this technology has a broad practical application prospect. INDEX TERMS AC-AC frequency conversion, high voltage, large capacity, MATLAB.

Researching on Multiple “Phase Hopping” AC-AC Frequency Conversion Circuit

“…Two sets of bridge rectifier circuits are connected in reverse parallel, the input threephase power is ABC, and the terminals of the output singlephase sine wave are P and O. Based on basic AC-AC frequency conversion theory, the "phase hopping" frequency conversion technology is adopted [13], [14], [15], and [16]. Equation ( 1) is the phase that decreases with the number of jumps M in a cycle of the output voltage.…”