Abstract: A circuit for a hybrid voltage source converter suitable for high voltage DC power transmission and reactive power compensation. The circuit comprises an assembly of electrically interconnected elements (Elements 1 to 20) including a plurality of first elements (Elements 1 to 6) and a plurality of second elements (Elements 7 to 20). Each of the first and second elements is configurable to be bypassed, to be disconnected or to include a circuit arrangement of one or more electronic components to construct, in use, a hybrid voltage source converter including at least one first element and at least one second element and in which the circuit arrangement included in the or each first element is different to the circuit arrangement included in the or each second element.

Abstract: There is provided a method of switching on a semiconductor device. The semiconductor device includes gate, collector and emitter terminals. The method includes the steps of: (i) applying, upon receipt of a switch-on signal, a voltage to the gate terminal of the semiconductor device to decrease a collector-emitter voltage of the semiconductor device to a first predetermined voltage plateau level, and maintaining that voltage to the gate terminal of the semiconductor device for a predetermined time period; (ii) after the predetermined time period, controlling the voltage applied to the gate terminal of the semiconductor device to change the collector-emitter voltage at varying ramp-rates until the collector-emitter voltage reaches a predetermined voltage level; and (iii) controlling the voltage applied to the gate terminal of the semiconductor device to maintain the collector-emitter voltage at the predetermined voltage level.

Abstract: A static synchronous compensator for use in reactive power compensation, the static synchronous compensator comprising at least one primary compensator limb including first and second DC terminals, and an AC terminal for connection in use to an AC network, the or each primary compensator limb defining first and second limb portions, each limb portion—including at least one switching element connected in series with a chain-link converter—between a respective one of the first and second DC terminals and the AC terminal, the switching elements of the first and second limb portions being operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal and the chain-link converters being operable to generate a voltage waveform at the AC terminal; and a secondary compensator limb including at least one DC link capacitor connected between the first and second DC terminals, the secondary compensator limb being connected in parallel with the or each

Abstract: The present invention relates to an ADA compliant detectable warning or guidance tile for pedestrian platforms, walkways, and sidewalks and the like having a detectable warning surface containing raised truncated domes detectable by the visually impaired in accordance with Americans with Disabilities Act (ADA): Accessibility Guidelines for Buildings and Facilities and being provided with one or more additional means on the top surface of the tile to provide visual or tactile information to sighted and visually impaired pedestrians.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises three converter limbs, each converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal for connection in use to a respective phase of a three-phase AC network, each converter limb defining first and second limb portions being connected in series between the respective AC terminal and a respective one of the first and second DC terminals, each limb portion including at least one switching element being controllable in use to facilitate power conversion between the AC and DC networks, the power electronic converter further including a plurality of auxiliary units, each auxiliary unit being operably associated with the respective phase of the AC network, each auxiliary unit including at least one module including a voltage source, the limb portions being controllable in use to define at least one three-phase static synchronous compen

Abstract: A voltage source converter comprising three phase elements defining a star connection in which a first end of each phase element is connected to a common junction; at least two converter limbs, each converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal connected in series with a second end of a phase element, each converter limb defining first and second limb portions, including a chain-link converter, each chain-link converter including chain-link modules; and a third DC terminal connected to the common junction of the star connection to define an auxiliary connection, wherein in use a current is injected into the auxiliary connection to modify a voltage of each chain-link module in each limb portion.

Abstract: A voltage source converter for use in high voltage DC power transmission and reactive power compensation. The voltage source converter comprises at least one converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal for connection in use to an AC network. The or each converter limb defines first and second limb portions, each limb portion including at least one switching element connected in series with a chain-link converter between a respective one of the first and second DC terminals and the AC terminal. The switching elements of the first and second limb portions is operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal. The chain-link converters are operable to generate a voltage waveform at the AC terminal.

Abstract: A voltage source converter comprising three phase elements defining a star connection in which a first end of each phase element is connected to a common junction; at least two converter limbs, each converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal connected in series with a second end of a phase element, each converter limb defining first and second limb portions, including a chain-link converter, each chain-link converter including chain-link modules; and a third DC terminal connected to the common junction of the star connection to define an auxiliary connection, wherein in use a current is injected into the auxiliary connection to modify a voltage of each chain-link module in each limb portion.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises three converter limbs, each converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal for connection in use to a respective phase of a three-phase AC network, each converter limb defining first and second limb portions being connected in series between the respective AC terminal and a respective one of the first and second DC terminals, each limb portion including at least one switching element being controllable in use to facilitate power conversion between the AC and DC networks, the power electronic converter further including a plurality of auxiliary units, each auxiliary unit being operably associated with the respective phase of the AC network, each auxiliary unit including at least one module including a voltage source, the limb portions being controllable in use to define at least one three-phase static synchronous compen

Abstract: A static synchronous compensator for use in reactive power compensation, the static synchronous compensator comprising at least one primary compensator limb including first and second DC terminals, and an AC terminal for connection in use to an AC network, the or each primary compensator limb defining first and second limb portions, each limb portion-including at least one switching element connected in series with a chain-link converter-between a respective one of the first and second DC terminate and the AC terminal, the switching elements of the first and second limb portions being operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal and the chain-link converters being operable to generate a voltage waveform at the AC terminal; and a secondary compensator limb including at least one DC link capacitor connected between the first and second DC terminals, the secondary compensator limb being connected in parallel with the or each

Abstract: The present invention relates to an ADA compliant detectable warning or guidance tile for pedestrian platforms, walkways, and sidewalks and the like having a detectable warning surface containing raised truncated domes detectable by the visually impaired in accordance with Americans with Disabilities Act (ADA): Accessibility Guidelines for Buildings and Facilities and being provided with one or more additional means on the top surface of the tile to provide visual or tactile information to sighted and visually impaired pedestrians.

Abstract: A circuit for a hybrid voltage source converter suitable for high voltage DC power transmission and reactive power compensation. The circuit comprises an assembly of electrically interconnected elements (Elements 1 to 20) including a plurality of first elements (Elements 1 to 6) and a plurality of second elements (Elements 7 to 20). Each of the first and second elements is configurable to be bypassed, to be disconnected or to include a circuit arrangement of one or more electronic components to construct, in use, a hybrid voltage source converter including at least one first element and at least one second element and in which the circuit arrangement included in the or each first element is different to the circuit arrangement included in the or each second element.

Abstract: A voltage source converter for use in high voltage DC power transmission and reactive power compensation. The voltage source converter comprises at least one converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal for connection in use to an AC network. The or each converter limb defines first and second limb portions each limb portion including at least one switching element connected in series with a chain-link converter between a respective one of the first and second DC terminals and the AC terminal. The switching elements of the first and second limb portions is operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal. The chain-link converters are operable to generate a voltage waveform at the AC terminal.

Abstract: A fuel system for an engine has a first summing amplifier to which are fed signals representing demanded and actual values of the output of a pump supplying fuel to the engine, together with a signal representing engine speed. The summing amplifier compares the signals it receives and produces an output controlling the output of the pump, and there is also a second summing amplifier to which are fed electrical signals representing engine speed and a reference, a discriminator coupling the two summing amplifiers to a means for controlling the pump, so that the output from the discriminator at any instant is the output from the amplifier demanding the least fuel.

Abstract: A fuel system for an engine has a pump which supplies fuel to the engine and an actuator for controlling the pump output. The actuator is controlled by a control circuit to which are fed electrical signals representing demanded engine speed, actual engine speed and pump output. The control circuit sets the slope of the pump output versus speed curves of the engine, and speed-sensitive means operates below a predetermined engine speed for modifying this slope to make it shallower and so produce a smaller change in pump output for a given change in speed.

Abstract: An engine fuel system, particularly for a compression ignition engine, has a control arrangement for determining the quantity of fuel injected in accordance with the position of a control member such as an accelerator pedal. For part of its movement, the pedal produces an output which is a certain function of the pedal position, and for another part of the movement, an output is produced which is a different function of the pedal position.