A circuit for testing an electronic component, such as a transformer, includes at least two power supplies and at least two H bridge circuits. A first H bridge circuit is conductively coupled in parallel to a first power supply. A second H bridge circuit is conductively coupled in parallel to a second power supply. The second H bridge circuit includes one or more anti-series diodes for preventing current from the first power supply from passing through the second H bridge circuit to the second power supply. The first H bridge circuit and the second H bridge circuit are configured to conductively couple to the electronic component for providing a voltage with a predefined waveform to the electronic component.

A gradient amplifier driver stage circuit includes: a gradient coil and a plurality of gradient driver modules electrically cascaded with each other and forming an output end, the output end being electrically connected to the gradient coil, wherein each gradient driver module includes a pre-stage power supply and a bridge amplifier connected in parallel, output voltage of the pre-stage power supplies of the plurality of gradient driver modules are the same, and each gradient driver module is configured to provide an inductive voltage drop and a resistive voltage drop on the gradient coil.

A power conversion method comprising: charging a plurality of energy storage devices of a power converter from an input power source; and sequentially coupling and decoupling energy storage devices of the plurality of energy storage devices to an output. Charging the plurality of energy storage devices comprises maintaining at least two of the plurality of energy storage devices at substantially different potentials.

A power conversion method comprising: charging a plurality of energy storage devices of a power converter from an input power source; and sequentially coupling and decoupling energy storage devices of the plurality of energy storage devices to an output. Charging the plurality of energy storage devices comprises maintaining at least two of the plurality of energy storage devices at substantially different potentials.

Described herein are multi-level inverters configured for a wireless power system and methods for such inverters and systems. The inverter includes at least one capacitor and at least one switching leg. Each switching leg including a plurality of switches having at least one switch coupled to the at least one capacitor. The plurality of switches of each switching leg are configured to be controlled such that, during operation: (i) an output voltage is produced, the output voltage having an asymmetric multilevel profile with at least four non-zero unequal voltage levels and (ii) at least one switch of the plurality of switches operates with zero-voltage switching.

Described herein are controllers configured for a wireless power system and methods for such controllers and systems. The controller includes a control module configured to generate a first control signal having a first voltage level and a second control signal having a second voltage level and a modulator configured to (a) receive a signal representative of the output current and (b) generate carrier signals based on the output current. When a first carrier signal is greater than the first voltage level, a first gate drive signal for a first switch is high and when a second carrier signal is greater than the second voltage level, a second gate drive signal for a second switch is high, thereby driving an inverter to output a multi-level voltage having a first output level based on the first drive signal and a second output level based on the second drive signal.

A pulse width modulation method, a pulse width modulation system, and a controller are provided, which change a change rate of a common-mode component of a three-phase converter upon a change of a converter modulation degree, thereby improving stability and harmonic characteristics of the three-phase converter and implementing flexible adaptive adjustment. An example pulse width modulation method includes: obtaining initial three-phase modulation waves and a converter modulation degree; calculating a common-mode-component change-rate adjustment coefficient based on preset modulation parameters and the converter modulation degree; selecting a modulation wave having a minimum absolute value from the modulation wave set as a common-mode modulation wave; and performing waveform superposition on the initial three-phase modulation waves and the common-mode modulation wave to obtain output three-phase modulation waves.

A rotary electric machine control apparatus (1) suitably controls two inverters (10) connected to associated ends of open windings (8). The rotary electric machine control apparatus (1) performs target control involving: controlling a first one of the inverters (10), which is selected from a first inverter (11) and a second inverter (12), by rectangular wave control; and controlling a second one of the inverters (10) by special pulse width modulation control that is one type of pulse width modulation control. The special pulse width modulation control is a control method to produce a switching pattern (Su2+) that is based on a difference between a switching pattern resulting from the pulse width modulation control and a switching pattern (Su1+) resulting from the rectangular wave control when a target voltage is to be generated in the open windings (8).

The present disclosure provides a gradient amplifier driver stage circuit, a gradient amplifier system and a control method thereof. The gradient amplifier driver stage circuit includes: a gradient coil and a plurality of gradient driver modules electrically cascaded with each other and forming an output end, the output end being electrically connected to the gradient coil, wherein each gradient driver module includes a pre-stage power supply and a bridge amplifier connected in parallel, output voltage of the pre-stage power supplies of the plurality of gradient driver modules are the same, and each gradient driver module is configured to provide an inductive voltage drop and a resistive voltage drop on the gradient coil.

A multilevel converter includes a power supply assembly with a plurality of phases, and a power cell assembly with first power cells and second power cells. The first power cells and second power cells have a same topology and a same current rating, and supply power to the plurality of phases of the power supply assembly. Each phase of the plurality of phases includes a first power cell and a second power cell of the power cell assembly, voltage ratings of the first power cells and the second power cells being different. Furthermore, a method for controlling a multilevel converter and an electric drive system comprising a multilevel converter are disclosed.