Utah State University

Uath State University

Dorai Babu Yelaverthi

Regan Andrew Zane

Hongjie Wang

Chakridhar Reddy Teeneti

A power converter includes an unfolder connected to a three-phase source and has an output connection with three output terminals. A three-input converter connected to the unfolder produces a quasi-sinusoidal output voltage across converter output terminals. Switches of the converter selectively connect each of the three output terminals across the converter output terminals. A pulse-width modulation controller controls a first duty ratio and a second duty ratio for the converter based on a phase angle of the source and a modulation index generated from an error signal related to a control variable. The duty ratios are time varying at a rate related to a fundamental frequency of the source. The modulation index relates to output voltage of the converter, peak voltage or current of the source and/or peak current at the output terminals.

Unfolder-based single-stage AC-AC conversion system

An power converter includes an unfolder connected to a three-phase source and has an output connection with a positive terminal, a negative terminal and a neutral terminal. The unfolder creates two unipolar piece-wise sinusoidal DC voltage waveforms offset by a half of a period. A three-input converter connected to the unfolder produces a quasi-sinusoidal output voltage across output terminals. Switches of the converter selectively connect the positive, negative and neutral inputs across the output terminals. A PWM controller controls a first duty ratio and a second duty ratio for the converter based on a phase angle of the source and a modulation index generated from an error signal related to a control variable. The duty ratios are time varying with a fundamental frequency of the source. The modulation index relates to output voltage of the converter, peak voltage or current of the source and/or peak current at the output terminals.

A power converter includes an unfolder with an input connection with three terminals that connect to a three-phase AC power source and that has an output connection with a positive terminal, a negative terminal and a neutral terminal. The unfolder unfolds the bipolar AC voltages into two unipolar piece-wise sinusoidal DC voltages offset from each other by a half of a period. The power converter includes a three-input converter that produces a DC voltage output across output terminals. The three-input converter includes a positive input connection connected to the positive terminal, a negative input connection connected to the negative terminal and a neutral input connection connected to the neutral terminal. The three-input converter includes switches that selectively connect a voltage to the positive, negative and neutral input connections across a primary transformer winding of a transformer. A secondary transformer winding is connected to the output terminals through a rectification section.

Quasi-single stage power converter topology

A power converter apparatus includes a plurality of inverters where each inverter receives power from a separate DC voltage source. The apparatus includes a magnetic structure. The magnetic structure includes a primary winding for each inverter, where each primary winding is connected to an output a corresponding inverter and each primary winding is coupled to a magnetic core, and a single secondary winding coupled to one or more magnetic cores to which each primary winding is coupled. The apparatus includes a rectifier that receives an AC waveform from the secondary winding and that rectifies the AC waveform and is connected to a load at output terminals. The secondary winding includes a secondary bus and the one or more magnetic cores of the magnetic structure that are arranged to provide a pathway for the secondary winding that minimizes a length of the secondary winding.

Growing community of inventors

North Logan, UT, United States of America

Dorai Babu Yelaverthi