196results about How to "Reduce reactive power" patented technology

A switching power supply circuit is disclosed which can achieve a high power conversion efficiency and besides achieve reduction of the circuit scale and the cost by simplification in circuit configuration. The switching power supply circuit includes a synchronous rectification circuit of the winding voltage detection system on the secondary side of a resonance converter. The coupling coefficient of an insulating converter transformer or the induced voltage level per one turn of the secondary winding is set so that the magnetic flux density of the insulating converter transformer may be lower than a fixed level thereby to maintain the secondary side rectification current in a continuous mode even in a heavy load condition. An inductor is inserted in series in a path along which rectification current is to be supplied to a secondary side smoothing capacitor so that reverse current appearing on the rectification current is suppressed by counter electromotive force generated in the inductor to further reduce the reactive power. A dc superposition characteristic of the inductor is set so that abnormal oscillation in a very light load condition (for example, 12.5 W or less) is prevented.

The invention provides lighting apparatuses which are power efficient, environment friendly and long lasting and can be manufactured with high degree of speed, accuracy and flexibility. The lighting apparatuses are easily serviceable and can be produced, transported economically and have higher economical value even on completion of life term of the lighting apparatuses. The present invention reduce the waste of raw material thereby utilizing maximum percentage raw material for produce solid state lighting fixtures using CAD and CNC process and provides retrofitting lighting apparatuses which can be replaced without making considerable changes in existing infrastructure.

The invention provides a network voltage disturbance generating device, which comprises a three-phase bridge type PWM (Pulse Width Modulation) rectifier and a three-H-bridge three-phase four-wire-system PWM inverter, wherein the alternating current side of the rectifier is connected with an electric network through an L type filter; the direct current side of the rectifier is connected in series with the direct current side of the three-H-bridge three-phase four-wire-system PWM inverter; an LC filter is connected to the alternating current side of the three-H-bridge three-phase four-wire-system PWM inverter; the output end of the LC filter is connected with an isolation transformer; and the secondary side of the isolation transformer is connected with a load. The invention further provides a control method suitable for the device. Due to the adoption of the device provided by the invention, the simulation of a network voltage amplitude, frequency disturbance and an electric network harmonic phenomenon can be realized, bilateral flow of energy can be realized, and active energy transmitted by tested solar-powered grid-connected equipment is fed back to the electric network; and the control method is easy and convenient to implement, and a target reference value can be accurately tracked; and moreover, quick response and small steady-state errors are realized, so that electric network disturbance can be simulated accurately.

The invention relates to a method for controlling drive pulses of a DAB type bidirectional isolation DC-DC converter. The method for controlling the drive pulses of the DAB type bidirectional isolation DC-DC converter comprises the steps of firstly, carrying out drive pulse control on the DAB type bidirectional isolation DC-DC converter based on a drive pulse working principle; and then inferring relevant formulas in the mode of control, and carrying out characteristic analysis and verification. The method for controlling the drive pulses of the DAB type bidirectional isolation DC-DC converter only needs to control a single variable, is simple and practical, applicable to the state of light load of a system, simple in algorithm, convenient to achieve, and prone to feedback regulation, reduces stress of devices, and effectively improves system efficiency when the system is in light load.

Present invention discloses pulse number modulation based atmospheric pressure glow discharge control method and circuit. Control method adopts pulse density modulation to generate alternate presented square wave pulsing signal to control inversion circuit switch tube on / off in glow discharge main circuit, each working period containing fixed quantitative square wave pulse, through keeping working period unchanged and changing working period square wave pulse number to control inversion circuit feeding energy time to load, realizing atmospheric pressure glow discharge load fixed frequently constant voltage control. The present invention can realize frequency follow-up control and linear power regulation to atmospheric pressure glow discharge type nonlinear variational capacitive loading.

A switching power circuit in which a synchronous rectification circuit of the winding voltage detection system by use of a resistance device is provided on the secondary side of a compound resonance type converter, whereby a high power conversion efficiency can be obtained, and a reduction in the circuit scale through circuit simplification can be had. The gap length of an insulated converter transformer is enlarged to set the coupling coefficient at about 0.8, and the numbers of turns of the primary winding and the secondary windings are so set that the induced voltage level in the secondary winding is not more than 2 V / T. This causes the secondary-side rectified current to be in a continuous mode even under a heavy load condition by setting the magnetic flux density of the core in the insulated converted transformer to be not more than a predetermined value. Further, with inductors inserted into each rectified current circuit on the secondary side, the back electromotive forces in the inductors suppress a backward current generated in the rectified current, whereby a further reduction in the reactive power can be obtained.

A method is provided for controlling a wind farm connected to a grid. The wind farm includes a wind farm emergency generator and at least a first wind turbine. The first wind turbine includes a wind turbine transformer, a wind turbine converter and auxiliary equipment. The method includes detecting a lost grid connection, providing active power to the auxiliary equipment via the wind farm emergency generator, providing reactive power via the wind turbine converter.

The invention belongs to the power transmission and transformation equipment field and relates to an energy-saving box type outdoor substation. The substation comprises a top cover and a box body; the box body is divided into a high-voltage chamber, a transformer chamber and a low-voltage chamber. The energy-saving box type outdoor substation further comprise an intelligent controller; the intelligent controller is connected with a low-voltage chamber power transmission line through a power source input cable; the high-voltage chamber is provided with a high-voltage entering cabinet, a high-voltage metering cabinet, a high-voltage ring main unit and a high-voltage outgoing cabinet; the low-voltage chamber is provided with a low-voltage entering cabinet, a high-voltage reactive power automatic compensation capacitor cabinet and a low-voltage outgoing cabinet; and a transformer arranged in the transformer chamber is an on-load automatic capacitance adjustment power distribution transformer. The energy-saving box type outdoor substation is safe, reliable, energy-saving and efficient. With the energy-saving box type outdoor substation adopted, a power factor as well as the power supply efficiency and voltage quality of a system can be improved, and line loss can be decreased, and distribution line cost can be decreased, and electric energy can be saved, and the occupancy of a power grid and the no-load reactive loss and active loss of the transformer can be decreased, and capacity increasing cost and operation cost can be saved, and saving energy and consumption reduction can be realized, and great economic benefits and social benefits can be brought about.

The invention discloses a receiver of a wireless charging system, a control method of the receiver, an electrical terminal, a transmitter of the wireless charging system and a wireless charging system. The receiver includes a receiving coil, a receiver compensation circuit, a rectifier and a controller; the controller adjusts a phase difference between first and second bridge arms of the rectifierand adjusts a phase shift angle between bridge arm voltage of the rectifier and input current fundamentals component of the rectifier, thereby allowing zero-voltage on and off of a controllable switch of the rectifier. The magnitude of the fundamental component of the bridge arm voltage is adjusted by adjusting the phase difference between the two bridge arms of the rectifier, thereby adjusting areal part of equivalent impedance of the rectifier. The equivalent impedance of the rectifier includes the real part and a virtual part; the real part refers to resistance; the virtual part refers toreactance. When the virtual part of the equivalent impedance of the rectifier is very small, the equivalent impedance of the rectifier is considered as pure-resistive impedance, and the controllableswitch tube gains ZVS (zero-voltage switching) effect. An inductance compensation module helps weaken the capacitive portion of the equivalent impedance, thereby lowering reactive power of the wireless charging system and improving system efficiency of the wireless charging system.

In a circuit module having components that are fastened to a substrate, the substrate includes a carrier layer made of metal and having a first surface, a first insulating layer bordering directly on the carrier layer being situated on the first surface. The substrate also includes a first wiring layer bordering directly on the first insulating layer, which conducts electrically and is situated on the first insulating layer. The substrate includes a first contact plane, which runs along the first surface, at least one of the components being directly connected electrically to the carrier layer in the first contact plane.

A wind power plant is provided. The wind power plant comprises at least one wind turbine and a power plant controller. The power plant controller is configured to detect whether a grid voltage exceeds a predefined threshold, and if it has detected that the grid voltage exceeds the predefined threshold, the power plant controller sends a reactive power reference to the at least one wind turbine, thereby causing the at least one wind turbine to reduce its reactive power output in response to the reactive power reference.

A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator comprises a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and is adapted to supply a current with a nearly sinusoidal waveform. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

A subfield lighting rate measuring unit detects a lighting rate for each subfield, and a subfield processor controls a scan driver and a sustain driver so that a recovery time of each sustain pulse, a resonance time of LC resonance and a sustain period become longer as the detected lighting rate for each subfield becomes smaller.

The invention provides a control method for improving the light-load efficiency of a DAB-type DC-DC converter and belongs to the technical field of modulation of bidirectional isolation DC-DC converter power switch tubes. Switch tubes on a diagonal of a full bridge at a side generate phase shift when a driving pulse is controlled so as to output a three-level voltage waveform. A full bridge at the other side is not required to be subjected to any phase shift control. The control method comprises two control modes. In the first mode, phase shift is performed on a bridge at an input side but is not performed on a bridge at an output side. In the second mode, phase shift is performed on the bridge at the output side but is not performed on the bridge at the input side. The control method is suitable for converter small-medium power output, greatly reduces the peak value and the effective value of the current flowing through a transformer, an inductor, and a switch device, effectively decreases device stress, greatly reduces system reactive power and system loss, and improves system efficiency.

The invention discloses a control device and method based on a phase angle of a phase current of a direct-current brushless motor. The control device comprises a speed setting module, a central processing unit, a current amplifying circuit, an intelligent power module, Hall sensors and a power source module which provides power for the speed setting module, the central processing unit, the current amplifying circuit, the intelligent power module and the Hall sensors. The control method comprises the steps that the real-time rotation speed of the direct-current brushless motor is collected and counter emf is obtained at the same time; the real-time phase current of the direct-current brushless motor is collected, and speed PI adjustment is conducted on a speed difference between the real-time rotation speed and a set rotation speed, so that a speed adjustment signal is obtained; PWM compensation calculation is conducted on the real-time counter emf and the phase deviation of the phase current of the direct-current brushless motor, so that a PWM compensation amount is obtained; a PWM duty ratio signal is obtained through calculation conducted by the central processing unit according to the speed adjustment signal and the PWM compensation amount; the PWM duty ratio signal is output to the intelligent power module, so that control over the phase of the phase current of the direct-current brushless motor is achieved. By the adoption of the control device and method based on the phase angle of the phase current of the direct-current brushless motor, the motor efficiency is improved, and the amount of emitted-heat is reduced.

Disclosed is a glass paste containing a glass powder and an organic component, wherein a black pigment is composed of a complex oxide having a spinel structure and containing Co element and one or more metal elements other than Co element. Consequently, the glass paste is suppressed in color degradation at high temperatures, and thus enables to form a pattern having excellent color and degree of blackness after sintering.

The invention relates to a method for determining the constant voltage compensation network topology of a wireless power transmission system. According to the compensation network, the output voltage of the wireless power transmission system is not affected by load, and not limited by a non-contact transformer parameter, and thereby the design of the non-contact transformer can be simplified. According to the method, the compensation circuit parameter is determined with the aim that the voltage gain of the system is not affected by the system, the input impedance of the system is pure resistive, and the system efficiency is maximal, then the constant voltage compensation network topology is determined, and the constant voltage compensation network topology of which four groups of primary and secondary resonant networks can all be equivalent to T-type or n-type networks. The output voltage of the IPT system is not limited by the parameter of the non-contact transformer, and the design of the non-contact transformer is simplified; and the constant voltage output and unit power factor which are not affected by the load can be achieved at the same time, the reactive power is reduced, the requirement on device stress is lowered, and the transmission efficiency is improved.

The invention discloses an induction heating power circuit which belongs to electric product field. The induction heating power circuit is composed of a main-control part and a power part. The main-control part comprises switch electrical source and drive part, oscillation excitation part, phase and voltage locking, load too-small detection, load too-large detection, voltage limitation protection, current limitation protection, soft start part, temperature protection part; the power part comprises sensor and core part composed of full bridge power tube. The induction heating power circuit uses four wire three phase output method, the heating electrical source operation is in safe and high-efficient method by processing reactive power compensation and harmonic management through reactor after rectification, accordingly, various hidden dangers of traditional resistance wire heating method is avoided. The induction heating power circuit can be wide used in plastic film blower, wire drawing machine, injection molding machine, granulator, rubber extruder, curing press, cable extruder, petroleum heating and bathroom heating in daily life etc.

A PDP (plasma display panel) includes: a front substrate; a rear substrate arranged opposite to the front substrate; front barrier ribs arranged between the front substrate and the rear substrate and formed of a dielectric material, the front barrier ribs partitioning discharge cells together with the front and rear substrates; front and rear discharge electrodes arranged within the front barrier ribs to surround the discharge cells, and extended in parallel along discharge cells of one row; address electrodes extended along discharge cells of another row intersecting with a row of the discharge cells where the front and rear discharge electrodes are arranged; phosphor layers arranged within the discharge cells; and a discharge gas injected in the discharge cells, in which the address electrode includes discharge portions formed in a loop shape disposed at the discharge cells and connecting portions connecting the discharge portions.

The invention disclosed buck power factor correction system. The system includes: a first storing device, for storing and discharging energy; a first converter device, coupled to the first storing device, for transferring and converting energy; a second storing device, coupled to the first storing device, for storing and discharging energy; and a second converter device, coupled to the second storing device, for transferring and converting energy.

The invention discloses a high power factor constant current light-emitting diode (LED) lighting circuit with a simple structure, a few components and a long LED service life. The high power factor constant current light-emitting diode (LED) lighting circuit comprises a rectifier circuit (1), an LED light source load (2), and a constant current source circuit (3). The high power factor constant current LED lighting circuit does not include a filter capacitor. An alternating current is rectified by the rectifier circuit (1) and then converted into a pulsating direct current. The pulsating direct current forms a loop through the LED light source load (2) and the constant current source circuit (3). The constant current source circuit (3) performs voltage regulation and current stabilization of the LED light source load (2). An LED light source load (4) comprises at least one group of a plurality of LEDs which are connected in series. A constant current source circuit (6) comprises at least one group of constant current source devices. Each group of constant current source devices comprises at least one depletion mode field effect transistor. The drain of the depletion mode field effect transistor is a contact. The source and the grid of the depletion mode field effect transistor are in short connection and form another contact. The high power factor constant current LED lighting circuit can be widely applied in field of LED lighting circuit.

A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator is consisted of a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and the supplied current is approximated to be a sinusoidal waveform. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

The invention provides a voltage wattless control partition method based on a generator electrical distance. The voltage wattless control partition method comprises steps that: a shortest path from generators to electrical buses is calculated based on a Dijkstra algorithm, an electrical distance from the generators to the electrical buses is calculated based on a branch reactance value on the shortest path, partitions to which the electrical buses and the generators belong are determined based on the electrical distance, a number of the partitions is consistent with a number of the generators, automatic partition merging is carried out to realize an optimal number, partition belonging of the electrical buses at partition boundaries is adjusted according to sensitivity of a generator wattless power to voltage amplitudes of the electrical buses at the partition boundaries. The voltage wattless control partition method divides an area grade electrical network into a plurality of weak tie sub-net according to a wattless decoupling principle, so wattless influence on an adjacent electrical network is reduced to a maximum degree when individual voltage wattless control of each subnet is carried out.

A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator is consisted of a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and is adapted to provide with a serial-connected virtual harmonic damping. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

The invention discloses an electric field coupled mobile power supply system for rail transit. The electric field coupled mobile power supply system includes a transmitting part, a receiving part and an energy transmission mechanism. The transmitting part mainly consists of a DC power supply, a high-frequency inverter circuit and a primary compensation network. The receiving part mainly consists of a secondary compensation network, a rectification and filter circuit and a resistive load. The energy transmission mechanism consists of an emitting electrode plate and a receiving electrode plate, and is connected between the transmitting part and the receiving part. The electric field coupled mobile power supply system achieves electric field coupled mobile power supply by moving the receiving electrode plate, improves flexibility, reduces the area and the occupation space of the electrode plates, reduces the reactive power through the reasonable configuration of the transmitting part and receiving part parameters, improves transmission efficiency and transmission power, and is stable.

Provided is a plasma display panel including a rear substrate, a front substrate separated from the rear substrate, a plurality of barrier ribs arranged between the front substrate and the rear substrate and adapted to define a plurality of discharge cells corresponding to a plurality of sub-pixels, a plurality of sustain electrode pairs comprising a plurality of first discharge electrodes and a plurality of second discharge electrodes extending parallel to each other and surrounding ones of the plurality of discharge cells, the plurality of sustain electrode pairs being adapted to generate a discharge, a plurality of address electrodes extending and surrounding the plurality of discharge cells and arranged in a direction that crosses the plurality of sustain electrode pairs, a plurality of phosphor layers arranged within the plurality of discharge cells and a discharge gas arranged within the plurality of discharge cells, wherein a predetermined number of sub-pixels form a unit pixel, and unit pixels adjacent to each other in a direction are spaced apart from each other by a predetermined distance.