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.

Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers. When the primary side leads the secondary side, the ultracapacitor/battery discharges and causes the UPS to supply power to the data center, and when the secondary side leads the primary side, power flows from the grid back to the UPS, thereby recharging the ultracapacitor/battery.

Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers. When the primary side leads the secondary side, the ultracapacitor/battery discharges and causes the UPS to supply power to the data center, and when the secondary side leads the primary side, power flows from the grid back to the UPS, thereby recharging the ultracapacitor/battery.

An automotive power converter may be controlled by detecting a magnitude of current output by a phase leg of the automotive power converter, selecting a mutual off time for switches of the phase leg according to the magnitude, and generating pulse width modulation signals for the switches having the mutual off time to operate the switches to transfer power between a traction battery and electric machine.

An automotive power converter may be controlled by detecting a magnitude of current output by a phase leg of the automotive power converter, selecting a mutual off time for switches of the phase leg according to the magnitude, and generating pulse width modulation signals for the switches having the mutual off time to operate the switches to transfer power between a traction battery and electric machine.

An output filter for a power train includes a piezoelectric transformer, a load element connected across the output of the piezoelectric transformer and an inductor connected to an input of the piezoelectric transformer.

An output filter for a power train includes a piezoelectric transformer, a load element connected across the output of the piezoelectric transformer and an inductor connected to an input of the piezoelectric transformer.

A DC-DC converter providing adaptive peak current control is disclosed. A DC-DC converter includes an inductor having first and second terminals coupled to a voltage source and a transistor, respectively. The DC-DC circuit further includes a control circuit configured to control activation of the transistor. A first control block of the control circuit controls the transistor (and thus the inductor peak current) using pulse frequency modulation (PFM). A second control block controls the transistor using pulse width modulation (PWM) and PFM. In a first mode of operation, the control circuit activates the transistor, using PFM, such that the peak-to-peak current through the inductor has a fixed value. In a second mode of operation, the control circuit activates the transistor such that the peak-to-peak current through the inductor is modulated, using both PWM and PFM.

A power-control device comprises an energy-import portion and an energy-export portion. The power-control device may additionally include a general processing and power supply circuit providing linear control of the power-control device's production of power to the load. The energy-import portion is coupled between a V.sub.LINE terminal and a load terminal, and is capable of importing energy to the load terminal during a first portion and a third portion of an alternating voltage V.sub.AC waveform. The energy-export portion is coupled between the load terminal and a NEU terminal, and is capable of exporting energy from the load terminal during a second portion and a fourth portion of the alternating voltage V.sub.AC waveform. The first, second, third and fourth portions of the alternating voltage V.sub.AC waveform are equal to a period of the alternating voltage V.sub.AC waveform and respectively are consecutive during the period of the alternating voltage V.sub.AC waveform. The power-control device provides variable power control to the load terminal in response to a variable on/off time of a PWM control signal.

A power-control device comprises an energy-import portion and an energy-export portion. The power-control device may additionally include a general processing and power supply circuit providing linear control of the power-control device's production of power to the load. The energy-import portion is coupled between a V.sub.LINE terminal and a load terminal, and is capable of importing energy to the load terminal during a first portion and a third portion of an alternating voltage V.sub.AC waveform. The energy-export portion is coupled between the load terminal and a NEU terminal, and is capable of exporting energy from the load terminal during a second portion and a fourth portion of the alternating voltage V.sub.AC waveform. The first, second, third and fourth portions of the alternating voltage V.sub.AC waveform are equal to a period of the alternating voltage V.sub.AC waveform and respectively are consecutive during the period of the alternating voltage V.sub.AC waveform. The power-control device provides variable power control to the load terminal in response to a variable on/off time of a PWM control signal.