Work

Optimized Switching-Frequency Control for Improved Efficiency in Three-Phase Isolated Y-Rectifiers

Year: 2026

Type: article

Abstract: The single-stage three-phase isolated Y-rectifier (iYR) merges power-factor correction and galvanic isolation into two conventional B6 bridges. Its power is conventionally regulated by the phase-shift angle alone at a fixed switching frequency. At light load, the transformer current then forms high-peak pulses whose rms value is large relative to the transferred power, and the efficiency falls. This paper proposes a hybrid phase-shift and variable-frequency control that raises the switching frequency as the load falls, without altering the internal space-vector timings. At the lightest tested load, about 300W, the measured rms current falls by roughly 50 when the frequency is raised from 25kHz to 80kHz. The loss-optimal frequency is identified from hardware measurements rather than from simulation, and is stored as a two-dimensional look-up table indexed on the power reference and the dc output voltage. The strategy is validated on a 3kW prototype over a 350V–450V dc-bus range and a 25kHz–80kHz frequency range. At 400V and 300W, the measured loss falls by 38.6, raising the efficiency from 85.1 to 90.3 . Two transformer designs differing only in the magnetizing inductance are compared, which sets the frequency range over which the strategy reduces the loss.

Source: Energies

DOI: 10.3390/en19204845

Authors: Khaled A. A. Mohammed, Ahmed Y. Farag, Paolo Mattavelli

Institution: University of Padua

Language: English

Topic: Advanced DC-DC Converters

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Industry, innovation and infrastructure

Open Access status: gold

Estimated APC paid: $3,137