A method provides current limitation in the event of transient voltage variations at an AC output of a multilevel inverter that includes a bridge circuit with a first DC input, a second DC input, a neutral terminal and a bridge output, as well as a line filter with a choke connected between the bridge output and the AC output, and a capacitor connected between the AC output and the neutral terminal. In the method, depending on the voltage at the capacitor, when a first current threshold is exceeded by the choke current, a regular operating mode is interrupted and measures for current limitation are initiated. A multilevel inverter is further disclosed including a control circuit that is configured to carry out such a method.

A current source inverter includes a first phase leg including a plurality of switching devices, a second phase leg including a plurality of switching devices, and a third phase leg including a plurality of switching devices. The current source inverter also includes a zero-state phase leg including at least one switching device, wherein the zero-state phase leg is configured to transition from an open state to prevent current flow to a closed state to allow current flow between a positive and negative terminal during a dead-band time.

A power converter circuit (300) comprising: a full bridge inverter and an resonance circuit and a control circuit. The full bridge comprises a first leg (HBx) and a second leg (HBy), each leg having two switches and a switching node between the switches, the switches of the first leg being different from those of the second leg. The resonance circuit is connected between said switching nodes, and comprises an inductance (Lp) in series 5 with a capacitance (Cr). The control circuit generates control signals for the switches in accordance with a predefined scheme having two energizing phases (φ1, φ3) and two passive conducting phases (φ2, φ4) with a configurable duty cycle (DC1, DC2) for achieving zero-voltage-switching (ZVS).

A power converter circuit (300) comprising: a full bridge inverter and an resonance circuit and a control circuit. The full bridge comprises a first leg (HBx) and a second leg (HBy), each leg having two switches and a switching node between the switches, the switches of the first leg being different from those of the second leg. The resonance circuit is connected between said switching nodes, and comprises an inductance (Lp) in series 5 with a capacitance (Cr). The control circuit generates control signals for the switches in accordance with a predefined scheme having two energizing phases (φ1, φ3) and two passive conducting phases (φ2, φ4) with a configurable duty cycle (DC1, DC2) for achieving zero-voltage-switching (ZVS).

In a method for operating a controllable converter with an intermediate circuit capacitor, the control behavior can be improved by transmitting, depending on an intermediate circuit voltage applied to the intermediate circuit capacitor, an additional power component via the controllable converter such that the electric current that is generated by the controllable converter for the additional power component counteracts an oscillation of the intermediate circuit voltage. The additional power component is transmitted by the controllable converter to a connected motor as a pulsating additional torque. Also described is a controllable converter with a control unit for carrying out a method, wherein the controllable converter has semiconductors that can be switched off, and an intermediate circuit capacitor designed as a film-type capacitor.

A power conversion apparatus with dual-mode control includes a bridge arm assembly, a capacitor assembly, and control unit. The bridge arm assembly includes a first bridge arm and a second bridge arm. The control unit selectively controls the first bridge arm to be operated in a voltage source switching mode or a current source switching mode according to the load type of a first load, and controls the second bridge arm to be operated in the voltage source switching mode or the current source switching mode according to the load type of a second load.

Claimed is a method for control in wireless power transfer systems and a wireless power transfer system implementing such method. The system comprises a transmitting inductor; a receiving inductor spaced apart from the transmitting inductor; a half bridge inverting circuit or a full bridge inverting circuit with constant switching frequency for driving the current in the transmitting inductor, wherein said half bridge inverting circuit comprises at least two switches, or said full bridge inverting circuit comprises at least two diagonal pairs of switches. The switches or diagonal pairs of switches are configured to be turned on complementarily, and the current amplitude in the transmitting inductor is controlled by varying the difference between the on-times of said switches. The claimed method and system provide efficient power transfer in conditions of variable load and/or variable input voltage and/or variable coupling between Tx and Rx parts.

A power conversion apparatus with dual-mode control includes a bridge arm assembly, a capacitor assembly, and control unit. The bridge arm assembly includes a first bridge arm and a second bridge arm. The control unit selectively controls the first bridge arm to be operated in a voltage source switching mode or a current source switching mode according to the load type of a first load, and controls the second bridge arm to be operated in the voltage source switching mode or the current source switching mode according to the load type of a second load.

There is provided a semiconductor device capable of decreasing a switching loss. The semiconductor device has first semiconductor elements (Su)-(Sw) and second semiconductor elements (Sx)-(Sz) connected in series, in which the first semiconductor element includes a low switching loss semiconductor element having a switching loss which is smaller than a switching loss of the second semiconductor element and the second semiconductor element includes a low conduction loss semiconductor element having a conduction loss which is smaller than a conduction loss of the first semiconductor element.

A high-power motor controlled by parallelly connected windings is provided. The motor comprises multi-phase windings. Each phase includes n winding branches and 2n power devices, wherein the n winding branches are connected in parallel with each other, and each winding branch is independently controlled by a power device.