An electronic transformer including a controller and a dimming control circuit. The controller is configured to control an output voltage. The dimming control circuit is configured to receive a user-input and output a control signal based on the user-input. The controller varies the output voltage based on the control signal. Wherein the output voltage is substantially the same regardless of an amplitude of an input voltage.

An arrangement provides an AC current to a load for direct electrical heating. The arrangement includes a AC-DC-AC converter cell. The converter cell has at least two converter input terminals connected to at least two transformer output terminals. The converter cell has a first converter output terminal and a second converter output terminal, wherein the first converter cell output terminal is adapted to be connected to the load.

A current control method and a motor control circuit are provided. The motor control circuit includes a first rectification circuit and a second rectification circuit connected in parallel between a live wire and a natural wire of a power supply, a sampling resistor, and a controller connected to the second rectification circuit. The first rectification circuit is connected to the motor. The current control method include obtaining a periodic waveform signal of a bus voltage; collecting a bus current value through the sampling resistor; sampling the periodic waveform signal for a plurality of times; linearly fitting multiple voltage values obtained at a plurality of sampling time points to obtain multiple slopes; obtaining a power frequency according to the multiple slopes; calculating a compensation current value according to the power frequency; and generating a control signal according to the compensation current value and the bus current value.

A frequency converter has a control unit. The control unit has: a serial control unit interface, a control unit clock pulse generator for generating a control unit clock pulse, wherein data are transmitted via the serial control unit interface depending on the control unit clock pulse, and a control unit processor which is designed to define at least one control parameter depending on at least one actual value. The frequency converter furthermore has a power unit which has a data connection to the control unit and has: a number of power semiconductors, a power unit clock pulse generator for generating an adjustable power unit clock pulse, a serial power unit interface which is connectable to the control unit interface in order to set up a data connection, a clock pulse generator adjustment unit which has a signal connection to the power unit interface and which is designed to adjust the power unit clock pulse depending on signals which are received by the power unit on the power unit interface, a power unit processor which is designed to control the power semiconductors depending on the control parameter and the power unit clock pulse, and at least one sensor unit which is designed to determine the at least one actual value, wherein the control unit is designed to transmit the at least one control parameter via the control unit interface to the power unit, and wherein the power unit is designed to transmit the at least one actual value via the power unit interface to the control unit.

A frequency converter has a control unit. The control unit has: a serial control unit interface, a control unit clock pulse generator for generating a control unit clock pulse, wherein data are transmitted via the serial control unit interface depending on the control unit clock pulse, and a control unit processor which is designed to define at least one control parameter depending on at least one actual value. The frequency converter furthermore has a power unit which has a data connection to the control unit and has: a number of power semiconductors, a power unit clock pulse generator for generating an adjustable power unit clock pulse, a serial power unit interface which is connectable to the control unit interface in order to set up a data connection, a clock pulse generator adjustment unit which has a signal connection to the power unit interface and which is designed to adjust the power unit clock pulse depending on signals which are received by the power unit on the power unit interface, a power unit processor which is designed to control the power semiconductors depending on the control parameter and the power unit clock pulse, and at least one sensor unit which is designed to determine the at least one actual value, wherein the control unit is designed to transmit the at least one control parameter via the control unit interface to the power unit, and wherein the power unit is designed to transmit the at least one actual value via the power unit interface to the control unit.

A multilevel rectifier includes an input lead, a switching module, and a multilevel direct current (DC) link. The switching module includes a plurality of switch devices connected to the input lead. The multilevel DC link includes a positive lead, a midpoint lead, and a negative lead. each connected to the switching module. The plurality of switching module switch devices are operatively connected between the input lead and the DC link to provide a greater number of output voltage levels than the number of leads in the DC link with unidirectional power flow capability.

A multilevel rectifier includes an input lead, a switching module, and a multilevel direct current (DC) link. The switching module includes a plurality of switch devices connected to the input lead. The multilevel DC link includes a positive lead, a midpoint lead, and a negative lead. each connected to the switching module. The plurality of switching module switch devices are operatively connected between the input lead and the DC link to provide a greater number of output voltage levels than the number of leads in the DC link with unidirectional power flow capability.

A semiconductor switching circuit, for use in a HVDC power converter, comprising: a main semiconductor switching element, including first and second connection terminals between which current flows from the first connection terminal to the second connection terminal and an auxiliary semiconductor switching element electrically connected between the first and second connection terminals thereof, and a control unit, operatively connected to auxiliary semiconductor switching element and programmed to control the switching element to create an alternative current path between the first and second connection terminals by at least two of: a fully-on mode in which the switching element is operated at its maximum rated base current or gate voltage; a pulsed switched mode in which the switching element is turned on and off; and an active mode in which the switching element is operated with a continuously variable base current or gate voltage.

A semiconductor switching circuit, for use in a HVDC power converter, comprising: a main semiconductor switching element, including first and second connection terminals between which current flows from the first connection terminal to the second connection terminal and an auxiliary semiconductor switching element electrically connected between the first and second connection terminals thereof, and a control unit, operatively connected to auxiliary semiconductor switching element and programmed to control the switching element to create an alternative current path between the first and second connection terminals by at least two of: a fully-on mode in which the switching element is operated at its maximum rated base current or gate voltage; a pulsed switched mode in which the switching element is turned on and off; and an active mode in which the switching element is operated with a continuously variable base current or gate voltage.

For operating multi-axis drive assemblies more reliably even in a field weakening range, a current conversion device is proposed which includes a voltage-source DC link, a plurality of inverters having each a DC input side connected to the voltage-source DC link and AC output-side terminals for connection to an electric motor, and a control device configured to short-circuit each of the inverters. A measurement device measures an electrical variable at each of the inverters. The control device determines based on the measured electrical variables independently for each of the inverters directly or indirectly whether a particular inverter is feeding energy into the voltage-source DC link, and short-circuits, when this is the case, the particular inverter independently of the other inverters. A corresponding operating method is also disclosed.