238results about How to "Reduce reactive power loss" patented technology

The present invention discloses an electric converter circuit topological structure and a control method thereof. The circuit topology comprises a full-bridge inverter, a primary side resonance dynamic compensation network, a primary side coil, a secondary coil, a secondary resonance dynamic compensation network, a full-bridge synchronous rectifier and a load. The primary side resonance dynamic compensation network employs a structure of connection in series of a compensation inductor and an adjustable resonance capacitor, the secondary resonance dynamic compensation network employs a structure of connection in series of a coil and the adjustable resonance capacitor, in the conditions that system parameters are changed caused by factors such as different coil coupling coefficients, different loads, the temperatures and device production manufacturing errors, the PWM duty ratio of a capacitive switching switch is regulated to generate continuously changed and adjustable equivalent resonant capacitance to perform dynamic compensation for the resonance network to achieve the soft switch of the full-bridge inverter and minimize the reactive power in the energy transmission of the system so as to maximum the electric energy transmission efficiency of the system and effectively enhance the regulation ability of the system output features in a condition of the constant working frequency of the system.

The invention discloses a reactive voltage control method and system for a grid-connected photovoltaic power station. A three-layer reactive power control strategy is adopted to coordinate the reactive output between a reactive compensation device and a photovoltaic power generation unit and between inverters of a single photovoltaic power generation unit. Under the control strategy, the reactive voltage support is provided for the power grid; the photovoltaic power station can effectively regulate the power grid voltage; the active loss and the reactive loss of the power grid are minimal on the premise of keeping the power grid voltage within the required range. A photovoltaic array power reduction running strategy is further combined, the stable operation of the power grid is ensured on the premise of maintaining a certain reactive output capacity of the photovoltaic power station. The reactive voltage control method and the system solve the problem that the voltage at the grid-connected point is out of limit, which is caused by the fact that the large-scale photovoltaic power station is connected to the power grid, increase the permeability of the photovoltaic current in the power grid, and improve the stable running performance of the power grid voltage.

The invention discloses a five-degree-of-freedom (five-DOF) bearing-free permanent magnet synchronous motor. Left and right conical bearing-free permanent magnet synchronous motors respectively arranged at the left and right ends of a motor shell are symmetrically connected to a mechanical rotating shaft; each conical bearing-free permanent magnet synchronous motor consists of a conical stator, atorque winding, a suspension force winding and a conical rotor; and a permanent magnet is mounted on the outer surface of the conical rotor, a jacket is fixedly sleeved outside the permanent magnet, the conical rotor is fixedly arranged on the mechanical rotating shaft, the conical stator is provided with a plurality of through slots in the axial direction, each through slot is divided into an inner layer and an outer layer in the radial direction, the suspension force winding and the torque winding are respectively placed in the inner layer and the outer layer, the pole number of the torque winding is as same as that of the permanent magnet, and the difference between the pole number of the suspension force winding and the pole number of the torque winding is 2. The five-DOF bearing-freepermanent magnet synchronous motor can simultaneously realize radial and axial five-DOF suspension of the rotor without an additional magnetic bearing, has the advantages of high integration, reducedvolume and high critical rotating speed, and is easy to realize high-power ultrahigh-speed operation.

The invention relates to a heat pump type clothes dryer which comprises a control system, a refrigeration system and an air circulation system, wherein the refrigeration system consists of a compressor, a condenser, an evaporator and a throttle valve, the air circulation system consists of a clothes drying barrel, an evaporator, an evaporator fan, a condenser, a condenser fan, a humid heat air flow passage, a low-temperature dry air flow passage and a dry air flow passage, the humid heat air flow passage is arranged between the clothes drying barrel and the evaporator, the low-temperature dry air flow passage is arranged between the evaporator and the condenser, the dry air flow passage is arranged between the condenser and the clothes drying barrel, the compressor is a variable-frequency compressor and comprise a first condenser and a second condenser group which are connected in series, and the output end of the first condenser is also provided with a by-pass pipeline so that refrigerants can selectively flow to the throttle valve through the by-pass pipeline. The heat pump type clothes dryer can be used for high temperature dehumidification in high moisture content, can be used for medium temperature dehumidification in low moisture content and has obvious energy saving effect.

The invention provides a method for controlling reactive voltage in an ultra-high voltage grid on the basis of improved economic voltage difference. For current simulation and problems in controlling the reactive voltage in the ultra-high voltage grid, the reactive voltage in the ultra-high voltage grid is balanced in real time by real-time coordination of low voltage side conventional reactive compensation with 500kV grid dynamic reactive compensation. The method allows real-time coordinated control for the low voltage side reactive compensation and 500kV grid side dynamic reactive compensation, and ensures real-time reactive power and efficient and economic operation of the ultra-high voltage grid. In addition, by the use of the method, operating frequency in conventional compensation switching can be reduced greatly, reactive loss of transformers is lowered further, and busbar voltage fluctuation caused by power fluctuation of tie lines is suppressed to a certain degree.

The invention relates to a permanent magnet inner cylinder type polymetallic synchronous magnetic separator and belongs to mineral machinery. The permanent inner cylinder type polymetallic synchronous magnetic separator consists of a power motor, a foundation, a permanent magnet roller, a support, a control cabinet, a feeding box, charging grooves, a charging brush roller and a transmission part;magnetic systems are distributed on the inner wall of a permanent magnet roller body from bottom to top sequentially; and when mineral powder to be separated passes through magnetic areas with different field intensities, different metal element powder particles are adsorbed by magnetic separation areas with different field intensities respectively according to respective specific susceptibility and then fall into the charging grooves which are distributed separately, so that the polymetallic single-machine same-roller synchronous classification separation is realized. The permanent magnet inner cylinder type polymetallic synchronous magnetic separator is suitable for the separation of complex polymetallic minerals and tailings and can also be applied to a dry separation process and a wetseparation process, and can also be applied to performing synchronous primary separation, precise separation and scavenging on one certain mine variety.

The invention discloses a current critical continuous unified control method for a bidirectional DC-DC converter, relates to a current critical continuous unified control method for a dual-active bridge bidirectional DC-DC converter, and belongs to the field of power electronics. According to the control method disclosed by the invention, voltages on a primary side and a secondary side of a transformer and a phase difference between the voltages are controlled to make the converter work in a transformer current critical continuous mode and reduce the ring current and conduction loss of the converter. In addition, a transformer current can be enabled to be in a critical continuous mode through a boundary condition and a control condition, so that the reactive loss of a circuit is reduced, the current stress of a switching tube and the ring current loss of the converter are reduced, and the efficiency and reliability of the converter can be improved. The method further can greatly lower the complexity of a control unit and realize real-time control. The method can be applied to high-frequency isolation switching power supplies.

The invention discloses a reluctance linear oscillating motor which axially assembles two excitation coils (2-1 and 2-2) and utilizes the pulsating direct current excitation of positive and passive half-periods of single-phase alternating current to be flowed in the two excitation coils (2-1 and 2-2) on the two ends of motor to make the magnetic field back and forth reposition between two ends of motor, and the iron core (8) of cylinder mover inside the motor utilizes the magneto-resistive least principle to back and forth reposition following the magnetic reluctance, and straightly repeating moves inside the cylinder with two-way output function; and it has the characters of plunger piston and cylinder of compressor to realize the continuous output of liquid or gas via the bridge rectifying tube formed by four one-way control valves on the two ends of motor. And the motor uses the silicone lubricant to make the high pressure gas output by the air compressor without oil and the two-way output structure of said reluctance linear oscillating motor can be demounted to supply linear driving motor with independent power source for impacting and compressing to simplify the structure of these machines.

The invention discloses a linear-regulated PFC control circuit which comprises a PFC input voltage sampling module, a PFC input current sampling module, a PFC output voltage sampling module, a PFC control circuit module, a PFC output voltage-boosting power circuit module and a PFC linear regulation module, wherein the PFC linear regulation module is used for generating a linear regulation parameter of the linear regulation for the current loop control executed by the PFC control circuit module within the range from a heavy load to a light load according to the input current sampled by the PFC input current sampling module, and the PFC control circuit module is used for generating a wave generating signal of the linear regulation control for the PFC output voltage-boosting power circuit module according to the linear regulation parameter. An inner loop parameter is linearly regulated by utilizing the size of the load or the input current to finish effective wave shape control and obtain index optimization within a full-load range, and meanwhile, the overall efficiency within the light-load range is improved and the reactive power loss is reduced.

The invention relates to a motor insulating bearing device and a manufacturing method thereof. The bearing device is characterized in that an insulating bushing is positioned at a circumference part between a bearing pedestal and a motor bearing, insulating space rings are arranged between the end of the insulating bushing and the motor bearing and an outer bearing cover and between the end thereof and an inner bearing cover, and a gap is left between the insulating space ring and the insulating bushing. The motor insulating bearing device is manufactured by a unique method, the formation of rotor axial current loop is prevented effectively and the electric corrosion damage of the motor bearing is avoided, thereby ensuring the reliable operation of the motor, prolonging the service life of the motor and decreasing the reactive power loss of the electric energy at the same time; the motor insulating bearing device has the advantages of reasonable structure design, reliable operational performance and convenient installation and maintenance, etc.

The invention provides a method for comprehensive evaluation of quiescent voltage stability and power angle stability by using resistance margin, belonging to the field of a power system. Based on a power flow quotation, the dynamic characteristic of system power is considered to be injected, relatively comprehensive dynamic equivalence is carried out on the system, from a view of a PV node, the relatively comprehensive dynamic equivalence impedance of the system and the resistance margin index of the node are calculated, and according to the resistance margin index of the node, whether the quiescent voltage and the power angle of the system are subjected to instability is rapidly judged, or the stability degree of the power angle of the PV node is judged. During online application, the calculation of the resistance margin index is independent of the prior knowledge of a load mode in the system. The method can be applicable for online analysis control and offline simulation analysis of the power system, system running and scheduling persons can conveniently take effective measures, the stability level of the system is improved, system planning is facilitated, the scheduling persons can conveniently adopt a reasonable design and running scheme, and the comprehensive static stability level and the economy of system running are improved.

The invention discloses an oil pumping machine which comprises a fixedly arranged driving host of a permanent magnet synchronous speed reducer, a pylon fixed on a foundation and a first oil pumping rod driven by the driving host, wherein a steel wire cable drum which is driven by an output shaft of the driving host and wound with two steel wire cables is arranged on the driving host; one end of one steel wire cable is fixed on the drum, while the other end is fixed and articulated to a guide wheel on the pylon through a wheel shaft and then connected with the first oil pumping rod; one end of the other steel wire cable is fixed on the drum, while the other end passes through the guide wheel and then is connected with a counterweight or directly connected with the counterweight without passing through the guide wheel; and the wheel shaft of the guide wheel and the axis of the steel cable drum are horizontally arranged in parallel. The invention has reduced energy consumption, simple structure and convenient maintenance, can conveniently adjust the stroke and the jig frequency of an oil well, has the functions of diagnosing and detecting the working state of the oil well at any time and can further realize digital control and remote network control. The oil pumping machine is used as a petroleum exploitation machine.

The invention relates to a self-cooling outer rotor motor. A rotor bracket assembly comprises a rotor bracket and permanent magnetic steel, the magnetic steel is bonded to the inner wall of a cavity of the rotor bracket and is in fit clearance connection with a stator assembly, the rotor bracket comprises an outer cylinder body and an end cover, the end cover is arranged at one end of the outer cylinder body, and a rotating shaft hole is formed in the middle of the end cover. The end cover is provided with a plurality of hollow blades, the blades are evenly distributed on the outer circumference of the rotating shaft hole, and the hollow end cover and the outer cylinder body together constitute an axial flow fan. A gap is reserved between the rotor bracket and a fixing frame assembly; thegap between the rotor bracket and the fixing frame assembly, a gap between the stator assembly and the magnetic steel and a gap between an inner cavity of the outer cylinder body and the end cover constitute a cold air and hot air circulation passage. By using stamping or precision casting, the blades are directly hollowed out on the rotor bracket to form the axial flow fan, so that the purpose ofrapid cooling of the motor without increasing the size of the motor is achieved.

The invention discloses a copper tube and an electric furnace energy-saving noninductive short net, wherein the copper tube comprises a first conductor and a second conductor axially sleeved on the periphery of the first conductor; a first insulation layer is filled between the first conductor and the second conductor; and the electric furnace energy-saving noninductive short net comprises a plurality of parallel conductive pipe fittings, each conductive pipe fitting comprises the first conductor and the second conductor axially sleeved on the periphery of the first conductor; and the first insulation layer is filled between each first conductor and the corresponding second conductor. By means of the electric furnace energy-saving noninductive short net provided by the invention, the defects of high inductive reactance, high impedance, low natural power factor, high unit power consumption and the like in the prior art are overcome, and the advantages of low inductive reactance, low impedance, high natural power factor and low unit power consumption are realized.

The invention relates to a reactive power compensation device for a 10kV or 6kV power transmission line, comprising a centralized measure-control device, at least one terminal compensation device; a first wireless network module and at least one second wireless network module. The centralized measure-control device is installed at a leading-out terminal of the power transmission line and used for measuring data parameters of the power transmission line and coordinating the reactive power compensation of the terminal compensation device; the terminal compensation device is installed on the power transmission line, and an installation position can be selected for the terminal compensation device according to different load conditions to carry out the reactive power compensation on the power transmission line. The invention not only has a function of collecting data, but also can uniformly allocating the compensation devices of compensation points on the line, thereby realizing the optimal compensation of the whole line, improving power factors of each point in the line and effectively reducing the reactive power consumption of the line.