38results about How to "Reduce reactive current" patented technology

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.

The invention discloses a bidirectional hybrid bridge DC-DC converter and a half-cycle volt-second area balance control method, and belongs to a high-frequency switching power supply in the electric power and electronic field. The bidirectional hybrid bridge DC-DC converter disclosed by the invention consists of a main circuit and a control circuit; the main circuit consists of an input side, a high-frequency transformer and an output side; and the control circuit comprises a controller and a driving circuit. Based on the proposed bidirectional hybrid bridge DC-DC converter, half-cycle volt-second area balance control is adopted; the leakage inductance current effective value in a power non-transfer stage can be reduced by adjusting the duty ratio of the input side and by performing the half-cycle volt-second area balance control at the same time, and reactive current can be decreased, thereby lowering circuit on-state loss and ring current loss caused by the current; meanwhile, wide-range soft switching of each switching tube device also can be realized; and in addition, by virtue of the half-cycle volt-second area balance control, real-time control of bidirectional power flow can be realized while the complexity level of the control unit also can be lowered.

Cell-to-cell connection plates (1) each integrally having a welding part (2) shaped to fall within a circular end of a battery case (7) and a connecting part (2) extending from this welding part (2) are provided. The cell-to-cell connection plates (1) are attached to one electrode terminal and the other electrode terminal of the battery case (7) by welding the welding parts (2), respectively. The connecting parts (3) of the respective cell-to-cell connection plates (1) attached to each adjoining pair of cylindrical batteries (Ba) are overlapped with each other and coupled into electric connection. Consequently, regardless of whether a plurality of cylindrical batteries (Ba) are axially arranged in series or radially juxtaposed, each adjoining two can be connected to each other by using the identical cell-to-cell connection plates (1) for cost reduction. It is also possible to provide a sufficient heat dissipation effect and achieve sufficient robustness and weight saving even when connecting large-sized cylindrical batteries.

The invention provides a filter for a specific sequence current bypass. The filter comprises a main filter inducer and an auxiliary filter inducer, and is characterized by also comprising a specific frequency series resonance circuit which consists of an inducer and a capacitor, wherein the series resonance frequency of the specific frequency series resonance circuit corresponds to the frequency of ripple current which flows through the main filter inducer. By arranging the series resonance circuit which consists of the inducer and the capacitor on the current bypass and ensuring that the resonance frequency of the series resonance circuit is the same as or similar to the frequency of the ripple current which flows through the main filter inducer, or is the same as or similar to the integral multiple of the frequency of the ripple current which flows through the main filter inducer, a low impedance passage is provided for switching on and off the ripple current, so that the total capacity of the inducer is effectively reduced and additional extra reactive current is greatly reduced. Therefore, equipment cost is greatly reduced and a good technical effect is achieved.

The present invention provides an internal compensation method of AC motor and its winding coupling method. The capacitor internal compensation uses the capacitor to make the interconnected star stator winding respectively produce its current superposition and phase-shifting action to make the resultant currents of two-to-four winding parts divided from every phase approach to that all the phasesare identical and numerical values are uniform so as to raise the induced potential of stator winding and reduce the loss of reactive current. The interconnected star winding has three compensation ends with two or three winding parts led from three-phase stator winding, and can be coupled into several forms of hexagonal-three-star form, hexagonal-six-star form, interconnected star and variable-electrode 3-V type.

A method of executing a bag of tasks application in a cluster over a distributed computing system, the cluster having a cluster resource manager. The method includes requesting that the cluster resource manager authorize access by a remote user of the distributed computing system to any idle nodes of the cluster, submitting a bag of tasks slave process to the cluster resource manager, loading the bag of tasks slave process in one of the idle nodes without an allocation operation, sequentially scheduling tasks from the bag of tasks to the bag of tasks slave process, and executing the bag of tasks slave process either until finished or until the node in which the bag of tasks slave process is loaded is required owing to a local allocation request.

The invention relates to a capacitor optimization configuration method based on an improved particle swarm optimization. The method comprises the following steps of S1, establishing a target functionwith improved voltage quality; S2, establishing a target function with reactive compensation reaching the standard; S3, establishing a target function with the total harmonic distortion rate reachingthe standard; S4, establishing a target function of parallel resonance frequency and series resonance frequency; and S5, establishing a multi-objective optimization model, and carrying out optimizingand configuring on the capacitor by adopting a particle swarm algorithm. Under the condition that resonance and voltage fluctuation are considered, the improved particle swarm algorithm is adopted, the inertia coefficient of the system is controlled by means of the method of presenting the linear descent along with the number of iterations, so that the algorithm can have high global searching performance when starting, the vicinity of the global optimum region can be quickly located, and meanwhile, high local searching performance is achieved; the established optimization model is not only applicable to electric power companies, the capacitor optimization configuration method based on an improved particle swarm optimization and other levels of power transmission and distribution managementdepartments, and is also suitable for a large-scale steel plant, a cement plant and other important harmonic source users.

A power amplifier circuit includes an amplifying transistor and a dc bias circuit for biasing the amplifier transistor to obtain a conduction angle of at least about 180 DEG . The dc bias circuit includes a dynamic bias boosting circuit for increasing the dc bias current provided to the amplifying transistor by the dc bias current in direct proportion to an increase in the input signal provided to the power amplifier. An input to the dc bias circuit is coupled to a stage of the power amplifier circuit by a capacitor. The bias boosting circuit permits the power amplifier circuits to operate in Class B or Class AB with improved linearity, improved efficiency and reduced idle current.

An amplifier circuit (1) comprising an amplifier transistor (QO) and a DC bias circuit (2) for biasing the amplifier transistor (QO) to obtain a conduction angle of at least approximately 180°. The DC bias circuit (2) includes a self-biased boost circuit having a Wilson current mirror (Q4, Q5, Q6) integrated with a cascode current mirror circuit (Q2, Q3) to An extended Wilson current mirror circuit (Q2-Q6) is formed having an output coupled to the control terminal of the amplifying transistor (QO) through a resistor (R1), and an extended Wilson current mirror circuit (Q2-Q6) is coupled to a common terminal (Gnd) capacitor (C2).

The invention discloses direct-heating type hot-pressing equipment suitable for producing large-size beryllium materials. The direct-heating type hot-pressing equipment is characterized in that a capacitance on-site compensation device is additionally arranged on a circuit system of an existing 300-ton hot-pressing furnace. The invention provides an equipment capacity expansion method for machining a beryllium material product with the diameter being 300-400 or even larger, and the technical difficulties of the equipment capacity for direct-heating type large-size beryllium material machining are broken through. In addition, the direct-heating type hot-pressing equipment has the advantages that the safe starting and producing capacity of the equipment is achieved, the heating capacity of the equipment is improved, and the rate of finished products is increased.

The invention provides a distribution network loss reduction method based on marketing and distribution big data fusion and a terminal, and the method comprises the steps of: acquiring distribution network operation data, and building a primary key relation between the data; constructing topology logic structure data of the distribution network; fusing the distribution network operation data and the topological logic structure data; respectively calculating user fine-grained loss and distribution network line fine-grained loss; optimizing the reactive power of the power grid; and after the topological logic data of the distribution network structure is established, according to the multi-branch tree topology expression model of the distribution network line, realizing the visualization of the data of the distribution network structure according to the line hierarchy and the topological relationship between branch lines, wires, towers and distribution transformer users. According to the method, on the basis of fusion of distribution network tower topology logic data and distribution transformer operation data, a current and reactive superposition algorithm is innovated, and distribution network line loss fine-grained management and control and distribution network reactive power reduction optimization scheme recommendation are realized; and a dynamic monitoring and early warning function of the operation condition of the distribution network is realized by using a structure visualization technology.

The invention relates to a voltage fault ride-through test method for a static var generator. The method specifically includes at least one static var generator for accompanying testing, the static var generators for accompanying testing and a to-be-tested static var generator are connected with the output end of a grid fault simulation test device in parallel, the reactive supporting current characteristics of the static var generators for accompanying testing under voltage fault ride-through are reversed, the reactive current output by the to-be-tested static var generators is offset partially or completely, so that the total current output by the grid fault simulation test device does not exceed the rated current of the grid fault simulation test device, and thus the purpose of reducingthe capacity requirement of the grid fault simulation test device and reducing the cost of a voltage fault ride-through test is achieved.