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2997results about How to "Small fluctuation" patented technology

Permanent magnet motor sliding mode control strategy

The invention pertains to the technical field permanent magnet motors, and relates to a permanent magnet motor sliding mode control strategy. The permanent magnet motor is controlled by adopting double-closed speed current. The permanent magnet motor sliding mode control strategy is characterized in that a sliding mode speed controller and an extended sliding mode observer are adopted in the control strategy, the sliding mode speed controller adopts an exponential approach law containing the speed error and the sliding mode surface information, the deviation between a given rotating speed and a feedback rotating speed is taken as the input quantity, and a q-axis current given value is outputted through the sliding mode control quantity; the extended sliding mode observer is used to estimate the rotor position, the rotating speed and the load torque on a real-time basis, the rotating speed and the rotor position are used to provide the information of speed closed-loop control and coordinate transformation, and the load torque is compensated to the sliding mode speed controller, so that the high-accuracy vector control of the permanent magnet motor can be realized. The control strategy of the invention can be used to make the system fast track a given speed in the dynamic state, reduce the speed overshoot and the current fluctuation, and improve the disturbance resistance performance of the system.
Owner:TIANJIN UNIV

Liquid crystal display device

A liquid crystal display device 1 of the invention has a liquid crystal display panel in which a liquid crystal layer 14 is provided between a TFT substrate 2 and a CF substrate 25 that has a common electrode 26, a light sensing component LS1 with a TFT photosensor that senses external light, and an illuminating means controlled according to the output of the light sensing component. The light sensing component is deployed at the periphery of the TFT substrate's display area DA and uses a thin film transistor as photosensor. A capacitor C is connected between source and drain electrodes SL, DL for such TFT photosensor. One of the capacitor's terminals is connected to a standard voltage source VS via a switch element SW, and the other to the common electrode 26. Voltage that is always lower than the voltage applied to the common electrode by an amount corresponding to a reverse bias voltage is applied to the gate electrode GL for the TFT photosensor. The capacitor's voltage a certain time after the switch element turns off is output. As a result, it will be possible to provide a liquid crystal display device in which the light sensing component incorporated in the liquid crystal display panel is not susceptible to the influence of the drive signals for the display panel, and in which the light sensing component does not induce deterioration of the liquid crystals.
Owner:JAPAN DISPLAY WEST

Enhanced vapor injection air-conditioning circulating system and control method thereof

The invention relates to a central air-conditioning system, in particular to a duct air conditioner, namely an enhanced vapor injection air-conditioning circulating system. A vapor injection side electronic expansion valve of the system is subject to discharge superheat control instead of vapor injection superheat control; high discharge superheat is guaranteed, and heating capacity of the system can be further improved by vapor injection; the system is especially applicable to variable frequency compressors; high heating capacity is kept even under different operating frequencies; the system operates stably and fluctuates little. The enhanced vapor injection air-conditioning circulating system comprises a controller, a compressor, a four-way valve, a vapor-liquid separator, an economizer, a solenoid valve and a coolant pipe. The compressor is a variable frequency compressor. The economizer is a plate economizer. The electronic expansion valve controls vapor injection. The vapor injection electronic expansion valve is subject to discharge superheat control instead of vapor injection superheat control; accordingly, high discharge superheat is guaranteed, and heating capacity of the system is further improved by vapor injection. The system is especially applicable to variable frequency compressors; the heating capacity is kept even under different operating frequencies; the system operates stably and fluctuates little.
Owner:QINGDAO HISENSE HITACHI AIR CONDITIONING SYST

Vertical sinter ore cooling machine capable of efficiently recycling sensible heat of sinter ores

The invention discloses a vertical sinter ore cooling machine capable of efficiently recycling the sensible heat of sinter ores, which pertains to the technical field of sintering equipment and is used for preventing air leak in the cooling course of sinter ores and effectively recycling the sensible heat of the sinter ores. The technical proposal of the invention is that: the cooling machine consists of a feeding part, a cooling part and a conveying part; the cooling part comprises a vertical closed body, a hot wind pipeline, a blower, as well as a hopper, an upper sealing valve, a pre-storing chamber, a lower sealing valve, a heat exchanging chamber, a wind distributing board, an isopiestic wind chamber and a discharging channel which are in sequence arranged on the body from top to bottom; an annular wind chamber is arranged between the pre-storing chamber and the heat exchanging chamber; the annular wind chamber is communicated with the hot wind pipeline; the isopiestic wind chamber is communicated with the blower; and wind shields and ore falling openings are distributed evenly on the wind distributing board . The vertical sinter ore cooling machine has the following advantages of: 1. an air leak rate near to 0; 2. improved gas-solid heat exchange efficiency of the cooling machine; 3. raised quality of the recycled hot air; and 4. being beneficial to increasing the utilization rate of exhaust-heat boilers. Based on the advantages, the vertical sinter ore cooling machine is expected to be used commonly as an upgraded replacement of the existing sinter cooling machine.
Owner:NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY +1

Rotational speed and torque control device and method of wind turbine generator set

ActiveCN102635499AEasy to implement flexible switchingReduce speedWind motor controlMachines/enginesConstant powerAngular degrees
The invention discloses a rotational speed and torque control method of a wind turbine generator set. Under the situation that the measured rotational speed of a power generator is higher than the rated rotational speed and the measured power exceeds the rated power, the torque is switched from a PI (proportional-integral) control way to a constant power control way; under the situation that the pitch angle is smaller than the optimal pitch angle and the measured rotational speed is lowered below the rated rotational speed, the toque is converted from the constant power control way to the PI control way; and the pitch angle is controlled in a PI control parameter non-linear adjustment way, and the pitch control is in an activated state within the whole normal working rotational speed range. According to the rotational speed and torque control method of the wind turbine generator set provided by the invention, the problem of greater fluctuation in the rotational speed caused by desynchrony of the two types of control can be avoided by changing control target points of two controllers in a transition region, the transition region is improved from the original points to a curve, the flexible switching of the control states is easier to realize, and the stability in operation of the unit and the power output of the unit can be ensured.
Owner:CSIC CHONGQING HAIZHUANG WINDPOWER EQUIP

Variable-gradient fractal lattice sandwiched reinforcement phase change heat sink

The invention discloses a variable-gradient fractal lattice sandwiched reinforcement phase change heat sink and aims to provide an efficient phase change heat sink which is high in heat exchange efficiency, has certain universality and can be developed in a serialization mode. The variable-gradient fractal lattice sandwiched reinforcement phase change heat sink is realized according to the following technical scheme: reinforcement heat transfer structures are distributed in a phase change heat sink shell in an array; each variable-gradient fractal lattice sandwiched unit takes a variable-gradient V structure as a first-stage reinforcement heat transfer structure (4) according to the heat transfer and heat exchange characteristics of the phase change heat sink; on this basis, at variable-gradient V-shaped ends of the first-stage reinforcement heat transfer structures, the variable-gradient V structures in the same shape are gradually increased to form multiple stages of reinforcement heat transfer structures, and the specific surface areas of the multiple stages of reinforcement heat transfer structures are multiplied in sequence; the first-stage reinforcement heat transfer structures can transfer heat to an area far away from a heat radiation bottom plate rapidly in a reinforcement mode, and the second-stage reinforcement heat transfer structures (5) and the third-stage reinforcement heat transfer structures can transfer heat to phase change material far away from the heat radiation bottom plate rapidly to complete heat exchange.
Owner:10TH RES INST OF CETC

Method of operating a turbine

InactiveUS6840734B2Great amount of energyReadily and easily and estimatedOptimise machine performanceWind motor controlRotation velocityTurbine
A method of controlling the speed of rotation of a turbine, the turbine comprising a rotor, the method comprising the steps of measuring or estimating power or torque related to the energy production of the turbine, processing the measured or estimated power or torque so as to obtain a corresponding rotational speed, comparing the obtained rotational speed to a first predefined threshold value and to a second predefined threshold value, the second predefined threshold value being larger than the first predefined threshold value, and controlling the speed of rotation of the rotor according to the obtained rotational speed, so as to obtain a predetermined energy production from the turbine, and in such a way that in case the obtained rotational speed does not exceed the first predefined threshold value, the predetermined energy production from the turbine is optimal, in case the obtained rotational speed exceeds the first predefined threshold value, but does not exceed the second predefined threshold value, the predetermined energy production from the turbine is optimal, in case the obtained rotational speed exceeds the second predefined threshold value, the speed of rotation of the rotor of the turbine is reduced in a predefined manner to a value corresponding to the first predefined threshold value.
Owner:FORSKNINGSCENTER RISO ROSKILDE

Direct current microgrid coordination control method including bus voltage compensation and dynamic allocation of load power

InactiveCN109861303AHigh precisionDistributed secondary control strategy has good performanceSingle network parallel feeding arrangementsPower oscillations reduction/preventionMicrogridEngineering
The invention discloses a direct current microgrid coordination control method including bus voltage compensation and dynamic allocation of load power. An independently operated direct current microgrid can be constructed, and includes a distributed power supply for realizing low-carbon power generation, an energy storage system for compensating the intermittence and randomness of the distributedpower supply and a frequently-used direct current load; defects of traditional droop control in the direct current microgrid and the reference value of bus voltage in a direct current microgrid systemcan be analyzed; distributed secondary control considering voltage adjusting control and current correction control can be provided, and a strategy performs compensation on the direct current bus voltage brought by the traditional droop control so that the bus voltage can be recovered to a rated value; and the high precision load power distribution can be achieved by continuously adjusting droopcoefficients. Thus, communication requirements can be reduced; and through the utilization of bottom broadband communication, the high performance of load power distribution of island direct current microgrids can be realized, the reliability of the system can be enhanced, balance of supply and demand can be ensured, and stable bus voltage and small fluctuation can be achieved.
Owner:ZHEJIANG UNIV OF TECH

Predictive form calling-out algorithm based on dynamic statistics process, switch dialing method and device

The invention relates to a predictive form calling-out algorithm based on a dynamic statistics process, a switch dialing method and device. The device includes a data input module, a predictive form calling-out algorithm module, a switch, a dynamic statistics module, a data storage module, and a data output display module. The data input module inputs initialization parameter data to the predictive form calling-out algorithm module. The predictive form calling-out algorithm module is connected to the switch for information interaction. The dynamic statistics module is connected to the data storage module and receives the data of the data storage module. The dynamic statistics module counts the statistics data with different frequencies and transmits the data to the predictive form calling-out algorithm module. At the same time the data display is performed through a data output interface. According the invention, statistics and prediction are carried out according to dialed historical data, the dialing number next moment is dynamically determined, the service utilization rate is improved when a target phone call loss rate is not exceeded as far as possible, and optimizing balance is reached and the artificial dialing is completely replaced.
Owner:上海翰声信息技术有限公司

Data cleaning and recovering algorithm of floating car related to multi-threshold space

The invention relates to a data cleaning and recovering algorithm of a floating car related to a multi-threshold space. The algorithm comprises the processes of: merging data of a road section into a data matrix, wherein the data is collected by the floating car within a plurality of days; further removing abnormal data in the data matrix according to a three-sigma filter rule after taking a day as a unit to primarily screen missing data and abnormal data in the data matrix; then recovering the missing data by respectively combining space similar characteristics of the road section by a weighted average method and an exponential smoothing method according to the type of the missing data; and finally, recovering high-frequency noise disturbance in data of the floating car by a principal component rebuilding method, thereby fully excavating regularity speed information of the floating car under the condition of not increasing the quantity of the floating car and additional handling equipment, and further, effectively improving the data quality of the floating car. The data cleaning and recovering algorithm can be used for cleaning and recovering work of regularity data of the floating car, and can provide reliable data for subsequent transportation planning and traffic identification.
Owner:TSINGHUA UNIV

Method for fast forwarding and fast rewinding video stream

The invention discloses a method for fast forwarding and fast rewinding a video stream, which comprises the following steps: analyzing a source video file and acquiring an index file comprising each I frame index information; when a fast forwarding or fast rewinding request is received, executing the following steps: a. positioning the current playing time of the video stream; b. inquiring the index file to acquire the index information of the current I frame proximal to the current playing time; c. utilizing the fast forwarding or fast rewinding multiple and the index information of the current I frame to determine the number NF of the I frames to be skipped; d. for the fast forwarding request, skipping NF numbered I frames backwards; for the fast rewinding request, skipping NF numbered I frames forwards; e. inquiring the next I frame from the index file, and according to the information of the I frame recorded in the index file, acquiring the real data of the I frame from a primary file and playing the real data of the I frame; and repeatedly executing the steps d-e until the last I frame of the index file is processed or other processing requests are received. The invention effectively solves the problems of waste of bandwidth and unstable code rate.
Owner:SHENZHEN IPANEL TECH LTD
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