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

The invention relates to a wind energy installation having a wind rotor (12), a generator (14) which is driven thereby and interacts with a converter (15) in order to produce electrical power, rotation-speed regulation (21) and converter control (25) which interacts therewith, wherein the rotation-speed regulation (21) outputs a nominal rotation speed signal (nref). Furthermore, additional regulation (3) is provided, which has an input (31) for an additional power and is designed to produce a rotation speed change signal therefrom, taking account of a rotator inertia moment, and to output this as an output signal, which is added to the nominal rotation speed signal via a logic element (29). Kinetic energy is taken from the wind rotor in a controlled manner by reducing the rotation speed and is converted by the generator (14) to additional electrical energy. This allows primary regulation power to be made available deliberately by rotation speed variation, to be precise even in unsteady wind conditions.

The invention provides a charging / discharging device and a charging / discharging system for an electric vehicle. The charging and discharging device comprises: a transformer which comprises a primary winding and a plurality of secondary windings, and the plurality of secondary windings at least comprise a first secondary winding and a second secondary winding; the plurality of ports that are respectively and electrically connected with a primary winding and a plurality of secondary windings of the transformer, and the plurality of ports at least comprise: a first port which is electrically connected with the primary winding through a first conversion circuit; a second port which is electrically connected with the first secondary winding through a second conversion circuit; the third port that is electrically connected with the second secondary winding through a third conversion circuit; and the first controllable switch that is connected between the first conversion circuit and the primary winding. The voltage of the first port of the charging and discharging device is a first voltage, the voltage of the second port is a second voltage, and the voltage of the third port is a third voltage.

An inter-cell connecting plate (1) having integrally a welding portion (2) to be included in the circular end surface of a cell case (7) and a connection portion (3) extending from the welding portion(2) is provided, welding portions (2) are respectively welded to one electrode terminal of the cell case (7) and the other electrode terminal to fix inter-cell connecting plates (1), and respective connection portions (3) of inter-cell connecting plates (1) respectively fixed to two adjoining cylindrical cells (Ba) are overlapped each other and linked in a electrically connected state, thereby making it possible to connect two adjoining cells together by the same inter-cell connecting plate (1) when a plurality of cylindrical cells (Ba) are disposed either in series axially or in parallel radially, whereby costs can be reduced, sufficient radiation effect is achieved, and sufficient robustness and weight reduction can be ensured even a large cylindrical cells are connected.

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.

A semiconductor device comprises a semiconductor substrate having a main surface; a semiconductor layer of a first conduction type provided on the main surface of said semiconductor substrate; a first buried layer of the first conduction type provided between said semiconductor layer and said semiconductor substrate; a first connection region of the first conduction type provided around said first buried layer, said first connection region extending from the surface of said semiconductor layer to said first buried layer; a switching element provided in the surface region of said semiconductor layer on said first buried layer; and a low breakdown-voltage element provided in a surface region of said semiconductor layer, said low breakdown-voltage element being closer to said first connection region than said switching element and having lower breakdown voltage than that of said switching element.

The invention relates to an intelligent control device of a high power energy saving electromagnetic stove, and the method thereof, The intelligent control device comprises a controllable rectifying and filtering module, a contravariant module and a microcomputer controlling module, which is characterized in that a three-phase alternating current power supply is rectified into an adjustable direct current power supply through the controllable rectifying and filtering module ; the direct current power supply is inverted into a high frequency alternating current power supply through the contravariant module, and then the electric energy is converted into electromagnetic energy to be radiated to the bottom of a cookware, and vortex flow is generated, and the cookware can be heated because ofthe thermal effect of the vortex flow; the microcomputer controlling module is the core of the entire system, which is used for collecting data and transmitting control information to each module; the device adopts a series of advanced control policies, such as the trigger control of the rectifier bridge of an PI regulator, the intelligent self-adaptive constant power control, the intelligent soft-start control, the intelligent cookware detection control, etc., and thereby the working stability and the security of the electromagnetic stove are enhanced. The harmonic pollution of the equipmentto the electric network can be reduced to the utmost extent when the electric energy of the electromagnetic stove is saved, and the electromagnetic stove is suitable for various kitchens and dining rooms.

Provided is an inverter control apparatus (5) incorporating therein a current reproduction unit (6) which inputs information from a DC-bus current detector 4 for detecting the instantaneous phase currents that flows into an electric motor (1) and that is contained in the DC-bus current flowing into the inverter (2) from a DC power source (3), and which reproduces phase currents that flow into the motor (1) on the basis of the values of the instantaneous phase currents, wherein, in the voltage saturation range, the current production unit (6) calculates the phase currents flowing into the motor (1) on the basis of the average DC-bus current obtained through filtering the DC-bus current and an instantaneous phase current for a single phase; and the voltage commands for the voltages to be applied to the inverter (2) is calculated by using the phase currents.

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 phases are 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.

The invention provides a distribution network loss reduction method and a terminal based on the integration of big data of operation and distribution, which can obtain distribution network operation data, establish a primary key relationship between the data, construct distribution network topology logical structure data, and compare distribution network operation data with topology Integrate the logical structure data; calculate the fine-grained loss of users and the fine-grained loss of the distribution network separately; optimize the reactive power of the power grid; after the topology logic data of the distribution network structure is established, the model is expressed according to the multi-branch tree topology of the distribution network. , and realize the visualization of distribution network structure data according to the line hierarchy and branch lines, wires, towers, and distribution transformer users. The method is based on the integration of distribution network tower topology logic data and distribution transformer operation data, and innovative current and reactive power superposition algorithm to realize fine-grained control of distribution network line loss and recommendation of distribution network reactive power reduction optimization scheme. Dynamic monitoring and early warning function of distribution network operation status.

The invention discloses a bidirectional DC-DC converter based on a double transformer structure and a power control method thereof, belonging to the field of power electronics. The converter of the invention is composed of a main circuit and a control circuit; the main circuit is composed of an input side, an output side and two transformers; the control circuit includes a controller and a driving circuit. The present invention controls the transformer T 1 The input side voltage v AC , Transformer T 2 The input side voltage v AB and the output side voltage v FG and v AC , v AB The phase shift angle between them can realize a wide range of soft switching of the converter under a wide range of voltage input, and at the same time can reduce the loss of the converter and improve the efficiency of the converter. At the same time, the proposed power control method is simple in calculation, reliable in real time, and improves the reliability and implementability of the system.

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.

The invention discloses a bidirectional hybrid bridge DC-DC converter and a half-cycle volt-second area balance control method, which belong to the direction of high-frequency switching power supply in the field of power electronics. The bidirectional hybrid bridge DC-DC converter disclosed by the invention is composed of a main circuit and a control circuit; the main circuit is composed of an input side, a high-frequency transformer and an output side; the control circuit includes a controller and a drive circuit. Based on the proposed bidirectional hybrid bridge DC-DC converter, half-cycle volt-second area balance control is employed. By adjusting the duty cycle of the input side and the half-cycle volt-second area balance control at the same time, the effective value of the leakage inductance current can be reduced in the stage when the power is not transmitted, the reactive current can be reduced, and the circuit on-state loss and circulating current loss caused by the current can be reduced. At the same time, a wide range of soft switching of each switch tube device can also be realized. In addition, the half-cycle volt-second area balance control can realize real-time control of bidirectional power flow while reducing the complexity of the control unit.