Pulse power supply systems and methods are disclosed. A method includes providing earth-ground-referenced control circuitry and providing floating pulsed-power circuitry. The method also includes providing a DC offset voltage to the return port of the pulsed-power circuitry with a DC offset module and providing a peak voltage to the pulsed-power circuitry with a DC voltage source. Power is applied from a power source of the control circuitry to a driver of the pulsed-power circuitry via a galvanically-isolating power path and a trigger signal is applied from the control circuitry to the driver via a galvanically-isolated signal path to prompt the driver to produce a driver signal. A voltage pulse is produced between the output port and the return port by closing the switch with the driver signal to couple the peak voltage to the output port.

Apparatus and method for multi-channel pulse sequencing to control the charging and discharging of two capacitors into an inductive load. The invention allows devices that produce alternating magnetic fields (induction heating, AC motors, metal detectors, MRIs, wireless communication) to operate above 100% efficiency; thereby producing a power gain. The results of this improvement will allow these devices to be portable and low cost.

Apparatus and method for multi-channel pulse sequencing to control the charging and discharging of two capacitors into an inductive load. The invention allows devices that produce alternating magnetic fields (induction heating, AC motors, metal detectors, MRIs, wireless communication) to operate above 100% efficiency; thereby producing a power gain. The results of this improvement will allow these devices to be portable and low cost.

Within a predetermined time range, record time information of status indication signals fed back by thyristor control units (TCU) of a converter valve. Perform statistics and comparison of the pieces of time information using a bias statistics method. Mark a thyristor level whose bias exceeds a preset value. And determine a probability of failure in the thyristor according to the marking result.

This application relates to methods and apparatus for handling a fault associated with a voltage source converter (VSC) for exchanging electrical power between an AC system (101, 102) and a DC system (106-1, 106-2). The VSC (104) is connected to the AC system via an interface apparatus, comprising a transformer (107) with a set of primary windings (202) for coupling to a plurality of AC phases (A, B, C) of the AC system. In embodiments of the disclosure the set of primary windings having a neutral point (N) and the interface apparatus includes a fault module (301) having an energy storage element (302) connected in parallel with a resistive element (303) between the neutral point of the set of primary windings and a reference voltage, such as ground. The fault module does not interfere with normal operation but in the event of a phase-to-ground fault on the secondary side of the transformer, can induce earlier zero-crossing in the AC phases than otherwise would be the case, thus allowing AC breaker (108) to open with a reduced arcing time.

A converter station includes two line-commutated converters for energy transmission through a bipolar high voltage direct current transmission link. The two converters are electrically connected in an anti-parallel circuit to the same pole of the high-voltage direct current transmission link. One of the converters is operated as a rectifier in an AC grid and the other converter is operated as an inverter in the AC grid. A station reactive power exchanged by the converter station with the AC grid is controlled by real power stipulations for converter real powers which are exchanged between the converters and the AC grid. A method for operating the converter station is also provided.

An objective of the invention is to provide a bidirectional power valve for current occurring in a high voltage DC conductor, control method therefor, hybrid multi-terminal HVDC System using the same. The bidirectional power valve includes a first power diode arrangement of a first conducting direction, a second power diode arrangement of a second conducting direction; a mechanical disconnector, being connected with the second power diode arrangement in series; wherein: the first power diode arrangement and the series-connected second power diode arrangement and the mechanical disconnector are connected in parallel; and the first conducting direction of the first power diode arrangement and the second conducting direction of the second power diode arrangement are opposite to each other. The current commutation and re-commutation can be achieved with less requirement of the timing accuracy of switching event which makes the usage of a mechanical disconnector and power diode feasible. This will then result in a significant reduction of cost and power transfer losses.

A line commutated converter (LCC) for a high voltage direct current power converter, the LCC comprising at least one LCC bridge circuit for connection to at least one terminal of a DC system, each bridge circuit comprising a plurality of arms, each associated with a respective phase of an AC system, each arm comprising: an upper thyristor valve or valves, and lower thyristor valve or valves connected in series; an associated branch extending from between the upper and lower thyristors; and at least one thyristor-based capacitor module for each phase, each module comprising a plurality of module thyristors, the or each capacitor module operable to insert a main capacitor into the respective arm of the bridge circuit by firing at least one or more of said module thyristors.

Apparatus and method for multi-channel pulse sequencing to control the charging and discharging of two capacitors into an inductive load. The invention allows devices that produce alternating magnetic fields (induction heating, AC motors, metal detectors, MRIs, wireless communication) to operate above 100% efficiency; thereby producing a power gain. The results of this improvement will allow these devices to be portable and low cost.

A first voltage source converter and converter station including such a first voltage source converter, as well as a method and computer program product for controlling the first voltage source converter are disclosed. The first voltage source converter has a DC side for connection to a DC system, has an AC side for connection to an AC system and is interconnected with an AC side of a second voltage source converter, which has a DC side connected to the DC system. The first voltage source converter includes a number of converter valve pairs, each being connected to a corresponding AC phase of the AC system and a control unit controlling the converter valves to generate at least one AC waveform and to reduce oscillations between the converters.