A high voltage switch comprising: a high voltage power supply providing power greater than about 5 kV; a control voltage power source; a plurality of switch modules arranged in series with respect to each other each of the plurality of switch modules configured to switch power from the high voltage power supply, and an output configured to output a pulsed output signal having a voltage greater than the rating of any switch of the plurality of switch modules, a pulse width less than 2 μs, and at a pulse frequency greater than 10 kHz.

A power facility for remote control includes: an analog sensing value reception unit that collects an internal analog sensing value of the power facility; a digital conversion unit that converts the analog sensing value into digital information; and a communication unit that transmits the digital information to an external remote control device by using one optical path. Therefore, by allowing a plurality of analog sensing values from the power facility to be transmitted to the remote control device by using one optical path, transmission efficiency can be increased, and by converting a plurality of analog sensing values of the power facility into digital information and transmitting the digital information with an asynchronous frame, the plurality of analog sensing values can be efficiently transmitted through one optical path without a separate synchronous signal.

Aspects of the present disclosure involve an inverter employing switches of different types in parallel. In one example, an apparatus includes a voltage-source converter that may have a plurality of switch positions collectively coupled to convert an input to an output. At least one switch position may include a first switch of a first switch type and a second switch of a second switch type different from the first switch type. Also, the first and second switches may be coupled in parallel. The converter may also include a switch control circuit to generate, for each of the at least one of the switch positions, a first control signal to operate the first switch of the switch position, and a second control signal to operate the second switch of the switch position.

A controller (3) includes an AC voltage generator (12) that generates first to Nth AC voltages, a DC voltage generator (13) that converts the first to Nth AC voltages into first to Nth DC voltages, respectively, and a driver (14) that turns on and off a switch (1) based on the first to Nth DC voltages. The AC voltage generator (12) includes first to Nth isolation transformers (T1 to TN). The primary windings of the nth and (n+1)th isolation transformers receive an AC source voltage. The nth to first isolation transformers are sequentially connected. The (n+1)th to Nth isolation transformers are sequentially connected. The first to Nth isolation transformers respectively output the first to Nth AC voltages from their respective secondary windings.

A power conversion device converts power between a direct-current (DC) circuit and an alternating-current (AC) circuit. The power conversion device includes a power converter circuit which includes a plurality of unit converters connected in series, and a controller. The unit converter includes one or more switching elements and a capacitor. The controller transmits, to the unit converter through a first transmission medium, information on a switching command for the unit converter. The unit converter transmits, to the controller through a second transmission medium, information on at least one condition of the unit converter. The first transmission medium is an optical fiber, and the second transmission medium is a wireless communication channel.

A control method includes the steps of: setting first control periods of a switching transistor group, the first control periods including operating periods in the first driving mode and operating periods in the second driving mode; setting an output voltage and a K value in a directly proportional relationship, wherein the K value is the ratio of the number of the operating periods in the second driving mode to the number of the operating periods in the first driving mode; receiving the output voltage, and determining a K value corresponding to the existing output voltage according to the set relationship between the output voltage and the K value; and outputting a driving signal group of the switching transistor group according to the number of the operating periods in the first driving mode and the number of the operating periods in the second driving mode.

An isolated communications apparatus applied to a transformer. The transformer includes N first rectifier units and a second rectifier unit, and the isolated communications apparatus includes N first control units, a second control unit, and a signal convergence unit. The first control units are connected to the first rectifier units in a one-to-one correspondence. Each first control unit is connected to the signal convergence unit, and the signal convergence unit and the second control unit are connected through an optical fiber. The signal convergence unit is configured to: receive first data packets from the N first control units, send the first data packets to the second control unit, receive at least one second data packet from the second control unit, determine a first control unit corresponding to each second data packet, and send each second data packet to a corresponding first control unit.

An isolated communications apparatus applied to a transformer. The transformer includes N first rectifier units and a second rectifier unit, and the isolated communications apparatus includes N first control units, a second control unit, and a signal convergence unit. The first control units are connected to the first rectifier units in a one-to-one correspondence. Each first control unit is connected to the signal convergence unit, and the signal convergence unit and the second control unit are connected through an optical fiber. The signal convergence unit is configured to: receive first data packets from the N first control units, send the first data packets to the second control unit, receive at least one second data packet from the second control unit, determine a first control unit corresponding to each second data packet, and send each second data packet to a corresponding first control unit.

A voltage source converter as well as a method and computer program product for controlling the converter. The converter includes at least one phase leg connected between a first DC terminal having a first voltage and a second DC terminal having a second voltage, the phase leg including an upper arm and a lower arm with cells, where a junction between the arms is connected to a corresponding AC terminal. The converter also includes a control unit configured to control the cells to output a train of pulses of trapezoidal shape where the generation of a first control signal for a first cell used to initiate a transition between two levels of a pulse coincides with the decision that a transition is to be made.

A voltage source converter as well as a method and computer program product for controlling the converter. The converter includes at least one phase leg connected between a first DC terminal having a first voltage and a second DC terminal having a second voltage, the phase leg including an upper arm and a lower arm with cells, where a junction between the arms is connected to a corresponding AC terminal. The converter also includes a control unit configured to control the cells to output a train of pulses of trapezoidal shape where the generation of a first control signal for a first cell used to initiate a transition between two levels of a pulse coincides with the decision that a transition is to be made.