三相三倍频变压器理论分析与样机研制

The frequency converter is a core component of fractional-frequency transmission systems. However, in special environments with high salinity and humidity, the reliability of existing power electronic frequency converters is significantly reduced, leading to increased operation and maintenance costs, limiting the application of fractional-frequency transmission systems. To address this issue, we studied the ferromagnetic frequency converter for fractional-frequency transmission systems. First, based on the principle of the magnetic frequency tripler, the principles for the core and winding structure were analyzed. A three-phase magnetic frequency tripler topology was then developed by introducing a phase-shifting winding on the primary side. Next, the effect of ferromagnetic saturation was taken into account, and a model of the magnetic frequency tripler incorporating strong nonlinearity was established. In combination with field-circuit coupled finite element analysis, a design method for the three-phase magnetic frequency tripler was proposed. Based on the theoretical investigations above, this study developed both a laboratory and an engineering prototype of the three-phase magnetic frequency tripler, achieving efficiencies of 92.8% and 94.8%, respectively, and improving the power quality. Moreover, the grid-tied test of the three-phase magnetic frequency tripler was conducted, verifying the effectiveness of the proposed analysis.