Abstract: 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.

Abstract: An apparatus for a transformer with an insulating divider includes a primary winding proximate to a primary magnetic core assembly and a secondary winding proximate to a secondary magnetic core assembly. The primary magnetic core assembly and the secondary magnetic core assembly are made of materials with a high magnetic permeability. The apparatus includes a divider placed between the primary and secondary magnetic core assemblies. The divider includes an electrically insulating material. The apparatus includes an electrically insulating potting material surrounding each of the magnetic core assemblies in a vicinity of the divider.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.