A multi-pulse line-interphase transformer converter includes an electric part that includes magnetic components configured to be connected to a three-phase AC grid, and an electric part that includes a multi-phase voltage system configured to be connected to a common DC capacitor. The electric part splits each AC grid phase n times into two phases, resulting in a plurality of intermediate phases at an internal interface, each intermediate phase corresponding to a pulse of the multi-pulse line-interphase transformer converter. The intermediate phases are connected to the multi-phase voltage system. The multi-phase voltage system comprises bridges with actively controlled switches. The bridges are connected in parallel to the common DC capacitor.

A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ω* of the motor 130 rises from a predetermined value.

A circuit includes two input nodes and two output nodes. A rectifier bridge is coupled to the input and output nodes. The rectifier bridge includes a first and second thyristors and a third thyristor coupled in series with a resistor in series. The series coupled third thyristor and resistor are coupled in parallel with one of the first and second thyristors. The first and second thyristors are controlled off, with the third thyristor controlled on, during start up with resistor functioning as an in in-rush current limiter circuit. In normal rectifying operation mode, the first and second thyristors are controlled on, with the third thyristor controlled off.

A circuit includes two input nodes and two output nodes. A rectifier bridge is coupled to the input and output nodes. The rectifier bridge includes a first and second thyristors and a third thyristor coupled in series with a resistor in series. The series coupled third thyristor and resistor are coupled in parallel with one of the first and second thyristors. The first and second thyristors are controlled off, with the third thyristor controlled on, during start up with resistor functioning as an in in-rush current limiter circuit. In normal rectifying operation mode, the first and second thyristors are controlled on, with the third thyristor controlled off.

The invention discloses a commutation failure protection method, and apparatus, computer device and storage medium thereof. The method comprises: collecting three-phase AC currents on a valve-side of a converter, a DC current on a high-voltage side and a DC current on a neutral terminal; selecting a minimum value of an absolute value of the three-phase AC currents on the valve side as an AC characteristic quantity, and selecting a maximum value of the DC current on the high-voltage side and the DC current on the neutral terminal as a DC characteristic quantity; according to the AC characteristic quantity and the DC characteristic quantity, constructing a minimum characteristic quantity; comparing the minimum characteristic quantity with a first preset threshold, and outputting a commutation judgment result; according to the commutation judgment result, constructing a commutation time interval; comparing the commutation time interval with a second preset threshold and a third preset threshold, and outputting a commutation failure protection judgment result to determine whether a commutation failure occurs. The invention uses minimum current sequence characteristics to track a commutation process of a converter valve, and when a commutation failure occurs, it may make timely, accurate and reliable judgment, thereby ensuring safe operation of valve equipment.

An isolation circuit for electrically isolating a first circuit operating at a first voltage from a second circuit operating at a second voltage that is different than the first voltage is provided. The isolation circuit includes: a first voltage source that operates at the first voltage, the first voltage source having a first supply rail and a second supply rail; an isolation device having a first input, a second input, a first output and a second output, the second input coupled to a first ground potential and the second output coupled to a second ground potential that is electrically isolated from the first ground potential by the isolation device; a first resistor coupled between the first supply rail and the first input of the isolation device; a second resistor coupled to the first input of the isolation device and the second input of the isolation device; and wherein the first output of the isolation device is coupled to the second circuit.

An isolation circuit for electrically isolating a first circuit operating at a first voltage from a second circuit operating at a second voltage that is different than the first voltage is provided. The isolation circuit includes: a first voltage source that operates at the first voltage, the first voltage source having a first supply rail and a second supply rail; an isolation device having a first input, a second input, a first output and a second output, the second input coupled to a first ground potential and the second output coupled to a second ground potential that is electrically isolated from the first ground potential by the isolation device; a first resistor coupled between the first supply rail and the first input of the isolation device; a second resistor coupled to the first input of the isolation device and the second input of the isolation device; and wherein the first output of the isolation device is coupled to the second circuit.

A converter includes first and second transistors coupled between first and second nodes, and first and second thyristors coupled between the first and second nodes. The converter is controlled for operation to: in first periods, turn the first transistor and second thyristor on and turn the second transistor and the first thyristor off, and in second periods, turn the first transistor and the second thyristor off and turn the second transistor and the first thyristor on. Further control of converter operation includes, for a third period following each first period, turning the first and second transistors off, turning the second thyristor off, and injecting a current into the gate of the first thyristor. Additional control of converter operation includes, for a fourth period following each second period, turning the first and second transistors off, turning the first thyristor off, and injecting a current into the gate of the second thyristor.

A supply device for a high-power load includes a DC/DC voltage converter disposed between a high-voltage side and a low-voltage side. The DC/DC voltage converter includes a first sub-converter and a second sub-converter. The sub-converters are connected to one another in a converter series circuit between first and second primary-side DC voltage poles. The second sub-converter is connected between first and second secondary-side DC voltage poles. The sub-converters each have at least one AC voltage terminal connected to one another by a coupling device to permit an exchange of electrical power between the first and second sub-converters. The secondary-side DC voltage poles are configured for connection to the high-power load. An arrangement for converting electrical energy into chemical energy with gas generation includes the supply device.

A switch-mode power supply includes a pair of input terminals for receiving an alternating current (AC) or direct current (DC) voltage input from an input power source, a pair of output terminals for supplying a direct current (DC) voltage output to a load, and a three-level LLC circuit coupled between the pair of input terminals and the pair of output terminals. The circuit includes a first switch coupled with a first diode to define a first half-bridge and a second switch coupled with a second diode to define a second half-bridge. The power supply further includes a third switch coupled across the first diode and the second diode to short circuit the first diode and the second diode when the third switch is closed, and a control circuit including a voltage-controlled oscillator (VCO), at least one flip-flop and multiple logic gates to operate the three switches with zero-voltage switching (ZVS).