1608 results about "Thyratron" patented technology

A load control device for controlling the amount of power delivered from an AC power source to an electrical load is operable to conduct enough current through a thyristor of a connected dimmer switch to exceed rated latching and holding currents of the thyristor. The load control device comprises a controllable-load circuit operable to conduct a controllable-load current through the thyristor of the dimmer switch. The load control device disables the controllable-load circuit when the phase-control voltage received from the dimmer switch is a reverse phase-control waveform. When the phase-control voltage received from the dimmer switch is a forward phase-control waveform, the load control device is operable to decrease the magnitude of the controllable-load current so as to conduct only enough current as is required in order to exceed rated latching and holding currents of the thyristor.

The invention relates to a grid synchroniser for connecting an AC output of a power converter to the AC grid mains. In one aspect the invention provides a grid synchroniser comprising an inverter controller to control an AC output of the inverter, the controller including a receiver to receive grid data from a grid sensor location remote from said inverter. In another aspect we describe techniques for rapid removal of charge from a control terminal of a power switching device such as a MOSFET, IGBT or Thyristor using a particular driver circuit.

A circuit for powering high-efficiency lighting devices from a thyristor-controlled dimmer predicts a zero-crossing time of the AC power line supplying the dimmer and causes a glue impedance to be imposed at the output of the dimmer starting at the time of the zero-crossing, so that the timer in the dimmer will operate properly to generate the turn-on event at the correct time. At turn-on, a lower level of impedance is presented to absorb the energy associated with the turn-on event. A higher level of impedance may be presented after the energy is absorbed until all of the energy needed for the cycle is transferred. Then, a high impedance state is maintained until the next zero-crossing time. The impedance control may be provided by non-uniform operation of a power converter that supplies the lighting devices, or by a combination of non-uniform power converter operation and dissipative loading.

A two-wire load control device (such as, a dimmer switch) for controlling the amount of power delivered from an AC power source to an electrical load (such as, a high-efficiency lighting load) includes a thyristor coupled between the source and the load, a gate coupling circuit coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

A power supply circuit for operating high-efficiency lighting devices from a thyristor-controlled dimmer determines the dimming value, i.e., the dimmer duty factor by periodically probing the dimmer output. A minimum conductance is applied across the output of the dimmer during probing intervals that begin at the turn-on time of the dimmer and last until enough information has been gathered to correctly predict a next zero crossing of the AC line voltage that supplies the input of the dimmer. The dimming value is determined from the time interval between the predicted zero-crossing and a next turn-on time of the dimmer. The probing can be performed at intervals of an odd number of half-cycles of the AC line frequency so that a DC offset is not introduced within internal timing circuits of the dimmer. The AC line frequency can also be determined from a time interval between the predicted zero crossings.

The invention relates to a sub-module circuit board used for a dynamic simulation test for simulating a high-capacity multi-level modular converter (MMC). A digital controller on the circuit board is used for controlling a plurality of MMC sub-modules of which parameters are reduced according to an exponential method, the sub-modules are connected in series. Each MMC sub-module comprises a main circuit an insulated gate bipolar transistor (IGBT) and silicon controlled rectifier driving circuit, a capacitance and voltage sampling circuit, a circuit board isolation power supply, a control and coding-decoding chip shared by a plurality of sub-modules, and a fiber channel, wherein the main circuit a capacitor, two IGBTs which are connected vertically in series and connected with the capacitor in parallel, a bypass switch connected with the lower IGBT in parallel, and a silicon controlled rectifier which is used for protecting the IGBTs and the capacitor and connected with the lower IGBT.

The invention relates to a circuit breaker and a realization method thereof, and specifically relates to a mixed high-voltage direct-current circuit breaker and a realization method thereof. The direct-current circuit breaker is based on the principle of secondary current transfer. A main branch is composed of a quick-action mechanical switch and a current transfer module which contains a full-controlled device, which ensures the advantages of low loss and flexible current transfer control in the state of normal conduction. A first current transfer branch is composed of half-controlled device thyristors connected in series, so that the circuit breaker has strong fault flow capacity and breaking capacity, 'zero voltage and zero current' of the mechanical switch can be maintained long enough, and arc-free switching of the mechanical switch is realized. A second current transfer branch is composed of capacitors with pre-charged voltage, an inductor, and series-connected thyristors. After the thyristors of the first current transfer branch are reliably switched off, the capacitors quickly build up direct voltage high enough to resist the system, and an energy absorption circuit limits the voltage of the capacitors. Thus, the size and cost of the capacitors are well controlled.

A hybrid light source comprises a discrete-spectrum lamp (for example, a fluorescent lamp) and a continuous-spectrum lamp (for example, a halogen lamp). A control circuit individually controls the amount of power delivered to the discrete-spectrum lamp and the continuous-spectrum lamp in response to a phase-controlled voltage generated by a connected dimmer switch, such that a total light output of the hybrid light source ranges throughout a dimming range. The discrete-spectrum lamp is turned off and the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity. The continuous-spectrum lamp is driven by a continuous-spectrum lamp drive circuit, which is operable to conduct a charging current of a power supply of the dimmer switch and to provide a path for enough current to flow through the hybrid light source, such that the magnitude of the current exceeds rated latching and holding currents of a thyristor of the dimmer.

A T-RAM memory cell includes a temperature compensation device to adjust the gate-to-source voltage of an access transistor for the memory cell as a function of temperature so that the sub-threshold current of the transistor is insensitive to temperature variations. As a result, the sub-threshold current can be maintained slightly above the holding current of a thyristor used in the memory cell despite substantial temperature variations. In one embodiment, the temperature compensation device includes a current source directing a fixed current through a diode-connected transistor of the type used as the memory cell access transistor. Temperature induced changes in a reference voltage generated at the junction between the current source and the transistor therefore match the temperature induced changed in the sub-threshold current of the access transistor. As a result, the sub-threshold current of the access transistor can be made insensitive to temperature variations by applying the reference voltage to the gate or source of the access transistor.

An anti-serial cascade circuit including two silicon carbide JFETs and two silicon MOSFETs is known. Disclosed is a combination of a JFET, a smart power MOSFET SPM and a thyristor with an associated trigger circuit, which is connected in parallel to the SPM. According to an embodiment of the invention, a logic circuit co-ordinates the functional sequence.

The invention relates to a passive switch drive controller for a hybrid AC contactor based on an opto-coupler, comprising a resistor (R1), a capacitor (C1), a resistor (R2), a rectifier bridge (Z), avoltage regulator tube (W), a capacitor (C2), a resistor (R3), an opto-coupler (G3), a resistor (R4), a resistor (R5), a resistor (R6), a bidirectional thyristor (J1), a bidirectional thyristor (J2) and a bidirectional thyristor (J3). The characteristics of the thyristors are sufficiently utilized; a control circuit adopts the opto-coupler to realize separation of an excitation power supply of thecontactor and electricity of a three-phase main circuit and unifiedly provides a switch signal controlled by the opto-coupler for a three-phase bidirectional thyristor; and a power supply and a current transformer are not required for configuration specially, so that the hybrid AC contactor based on opto-coupling separation and direct drive of switch control is realized. The passive switch drivecontroller not only realizes non-arc starting and disjunction, but also has the characteristics of simple control circuit, small volume, low cost, high performance index, strong universality, safety,reliability and the like.

The invention discloses a hybrid direct-current transmission converter. The hybrid direct-current transmission converter is provided with four topological structures which are series connection circuits formed by combining anodes and cathodes of current source type valve group units and positive electrodes and negative electrodes of voltage source type valve group units in different modes. Each current source type valve group unit only comprises a current source type valve group or comprises a current source type valve group and a bypass switch or comprises a current source type valve group, a bypass switch and a disconnecting link assembly. Each voltage source type valve group unit only comprises a voltage source type valve group or comprises a voltage source type valve group and a bypass circuit or comprises a voltage source type valve group, a bypass circuit and a disconnecting link assembly. A direct-current transmission device composed of the hybrid direct-current transmission converter effectively solves the problem of commutation failures of a direct-current transmission system based on thyristors and the problem of direct-current faults of a direct-current transmission system based on a voltage source converter, and has the advantages that loss is low, a reactive compensation device is not needed or a small number of reactive compensation devices are needed, and the direct-current transmission device can be connected into a passive alternating-current system and has the inverse power output function.

The invention discloses a power quality comprehensive compensation system of an electric railway and a control method thereof. The system comprises a railway static power controller RPC and two sets of thyristor switched capacitors TSC. The thyristor switched capacitors bear a large proportion of reactive power compensation, RPC performs active power compensation, harmonic suppression and a remained small proportion of reactive power compensation for two power supply arms, therefore, the capacity of RPC is effectively reduced, and negative sequence, harmonic and reactive comprehensive compensation are realized. The control method comprises a cooperative control policy of RPC and TSC, reference current detection based on reactive separation, a reactive power distribution method and an RPC control method. The power quality comprehensive compensation system of the electric railway greatly improves the power quality of the electric railway with low cost, and the corresponding control method effectively coordinates the operation of RPC and TSC and ensures that the system has good compensation performance and favorable application prospect.

The present invention relates to a test equipment of direct current thyristor valve, and particularly relates to a fault current test equipment of direct current thyristor valve. This present invention equipment includes high voltage low current circuit and low voltage high current circuit, said test equipment includes fault current circuit, said fault current circuit includes resonant circuit, said high voltage low current circuit, low voltage high current circuit and fault current circuit are all connected with the thyristor sample Vt respectively. In his present invention, the thyristor sample is first heated through the high voltage circuit and low voltage high current circuit to reach the stable state. And then shut off the switch and carries out the test using the fault current which is produced by the fault current circuit. This prevents the power system from the short-circuit impact. Further more, the peak current and the current duration of the fault current circuit can be adjusted flexibly by changing the voltage of the adding energy circuit.

The invention discloses a dynamic reactive power compensation system and a control method thereof. The system comprises a static reactive power compensator (DSTATCOM) used for continuing a sub-system, and a thyristor switching capacitor (TSC) used for scattering the sub-system, and a controller, wherein, the static reactive power compensator consists of a three-phase voltage type inverter and an inductor, and is connected with a plurality of thyristor switching capacitors in parallel on an electric network; wherein, the controller comprises an artificial neural net controller which is in reactive power intelligent control grade and is accessed into the DSTATCOM and a capacitor circulated controller which is in decision processing grade and is accessed into the TSC for circulated switching control of the capacitors. The invention realizes high capacity reactive power quick and continuous compensation with low cost, high efficiency and energy conservation; the control method based on the artificial neural net provided by the invention can deal with various uncertain factors of a complicated power system during operation process so as to improve the anti-interference capability of the system, not only has better dynamic compensation characteristic, but also improves the robustness and control precision of the system.

The invention discloses a quality control device and a method for resistance spot welding based on electrode displacement, which belongs to the technical field of welding. 380V alternating current power supply is added to the input end of a primary loop; under the controllable trigger of an anti-parallel thyristor; the alternating current voltage is reduced by a transformer and the welding energy is switched to a secondary loop; the heavy current acquired from the secondary loop welds workpieces; a spot welding part of the workpiece generates heat expansion and the expansion capacity is measured by an electrode displacement sensing device; a spot welding quality controller collects the displacement measured value of the electrode displacement sensing device and processes the numerical value to acquire the estimation of splashing prevention judgment and nugget size, thus acquiring a welding current control voltage signal and transmitting the signal to a trigger driving circuit; the trigger driving circuit sends trigger pulse to the anti-parallel thyristor to control a conduction angle of the thyristor, thus effectively regulating the welding current and controlling the welding quality. Therefore, the device can solve the real-time monitoring and control problem of the quality of the resistance spot welding well.

An exemplary parallel hybrid power filter apparatus for the electrified railway is described. The apparatus may include a group of LC reactive filter being purely tuned, an additional inductance, an active power filter and a coupling transformer. The active power filter may be controlled, e.g., as a current source in a composite control manner and can be connected in parallel to the additional inductance via the coupling transformer. The power filter can be connected to the reactive filter in series to form the parallel hybrid filtering system, and may be connected to the power grid via the circuit breaker or a thyristor. This exemplary system can be installed either in the traction substations or in the locomotives directly, or performed by ameliorating the original reactive filter. The active power filter does not add significant amount of cost, and may be simple and reliable in a control manner for the capacity of the APF is so small as to be less than one percent of that of the harmonics source. The power filter can also inhibit the impact of the “background harmonics” of the electrified railway on the reactive filter, and prevent the reactive filter and the grid impedance from resonance.

The invention relates to a submodule circuit board for a dynamic analog test for simulating a high-capacity modularized multi-level modular converte. A plurality of independent MMC (Multi-level Modular Converte) submodules reducing parameters according to an equitime constant method with a voltage level less than 50V are arranged on the circuit board; the plurality of submodules are completely independent and are of a series relationship; and the submodule comprises chips for controlling, coding and decoding, an optical fiber channel, a main circuit (provided with a capacitor and two IGBTs (insulated gate bipolar transistor) of an upper-lower series structure connected with the capacitor in parallel, a bypass switch connected with the lower IGBT in parallel, and a thyristor used for protecting the IGBTs and the capacitor and connected with the lower IGBT in parallel), an IGBT and thyristor drive circuit, a capacitance voltage sampling circuit, and a circuit board isolating power source which are respectively independent.