47results about How to "The calculated value is accurate" patented technology

The invention relates to an electric car driving motor torque closed-loop control method. The electric car driving motor torque closed-loop control method is composed of a whole vehicle control unit,a motor controller, an inversion switching circuit, a permanent magnet synchronous motor, a position sensor and a three-phase current sensor. The electric car driving motor torque closed-loop controlmethod is characterized in that whether active short circuit control is carried out according to an active short circuit control instruction (ASC-Enable) and the motor mechanical rotating speed, the output torque of the permanent magnet synchronous motor is calculated by means of an active short circuit method without depending on motor parameters such as stator resistance, rectangular axis voltage and the like, and the calculated value is more accurate; the motor controller then carries out PI regulation control according to a torque command emitted by the whole vehicle control unit and the torque on-line calculated value, the accuracy of the torque output absolute value can be improved, and the torque closed-loop response time is shortened.

Disclosed is an unloading control method for steel structure temporary bracing. The method comprises that simulation analysis of an overall construction process of an integral structure is performed, so that unloading quantities of various bracing points on a temporary bracing structure are determined, the integral structure comprises a main structure and the temporary bracing structure, and jacks are respectively arranged at positions of the bracing points on the temporary bracing structure for supporting the main structure; unloading is performed through adjustment of routes of the jacks; route changes of the jacks are measured based on the unloading quantities determined by the simulation analysis, so that the routes of the jacks are in accordance with the unloading quantities of corresponding bracing points determined by the simulation analysis; and the next step of unloading is performed in the same way, and finally synchronous unloading is achieved through grading sorted unloading. The unloading control method has the advantages that the routes of the jacks are used as control variables in unloading construction of the steel structure temporary bracing, the unloading quantities can be controlled accurately, real-time measurement is performed conveniently, the accuracy is high, the safety is guaranteed, and the like.

The invention relates to a thickness deviation-on-plate control method of a cold-rolled sheet. The invention adopts a cold rolling absolute thickness difference thickness deviation-on-plate control mode, a difference value of center thickness of strip steel and a set thickness value is calculated correspondingly so as to ensure the control mode of the thickness deviation-on-plate of the strip steel whole plate, the small fluctuation of the thickness of an edge part in the length direction of the strip steel is guaranteed, and a control strategy of bending roll first and displacement later is adopted; and a control scheme of the thickness deviation-on-plate thickness absolute value refers to the fact that when the thickness deviation-on-plate is controlled, an absolute value thickness control mode is adopted, a control mode is implemented according to a each thickness value of a transverse position. According to the method, a thickness deviation-on-plate overall level in a cold rollingrolling process can be enhanced, the thickness deviation-on-plate of a cold rolling high-thickness and high-precision product is improved, the cold rolling product quality is improved, the shearing amount is reduced, and the productivity is improved; the problems that an existing control mode is poor in control effect on the thickness deviation-on-plate, the length and width of the thickness valuesituation of the strip steel whole plate cannot be comprehensively reflected, and the yield is low are solved.

The invention relates to the technical field of oil and gas field gas production, in particular to a computational method of high-gas-liquid-ratio horizontal well critical liquid carrying flow. According to the computational method, the critical liquid-carrying flow rate of a vertical well section, a critical liquid-carrying flow rate of an inclined well section, and a critical liquid-carrying flow rate of a horizontal well section are computed, the one of the maximum value of the three flow rates is chosen as the critical liquid-carrying flow rate of a horizontal well, the horizontal well critical liquid-carrying flow is obtained according to a flow rate and flow computational formula to make computed critical liquid-carrying flow be larger than or equal to the actual critical liquid-carrying flow of the high-gas-liquid-ratio horizontal well, a worker can take corresponding treatment measures according to the computed values before liquid accumulates at the bottom of the well or at the early period of liquid accumulation at the bottom of the well to avoid affect caused to normal work of the gas recovery well by accumulation of formation water at the bottom of the well to the maximum degree, and working on the gas recovery well is stable as usual for sure; and the computational method of the high-gas-liquid-ratio horizontal well critical liquid carrying flow is simple in principle, easy to compute, and accurate in calculated value, and thereby being accurate and important basis for guidance in the high-gas-liquid-ratio horizontal well production technology in an oil and gasfield.

The invention provides an accelerator pedal minimum position self-learning method and system and a vehicle. The accelerator pedal minimum position self-learning method comprises the following steps ofobtaining a minimum position value during power-on and a minimum position value during power-off in a cycle when the vehicle is powered on; obtaining a voltage value corresponding an accelerator pedal opening in the current cycle; comparing the voltage value with a calibration threshold; and if the voltage value is less than or equal to the calibration threshold, carrying out self-learning according to a mean value of the voltage value; and if self-learning is failed, selecting a default value, the minimum position value during power-on or the minimum position value during power-off to perform self-learning according to a relation between the voltage value and the minimum position value during power-on and a relation between the voltage value and the minimum position value during power-off. According to the accelerator pedal minimum position self-learning method, the accuracy of calculation values of the accelerator pedal minimum position under various situations is guaranteed, the accuracy of the calculation of the accelerator pedal opening is guaranteed, the vehicle torque output accuracy is improved, and the running of the vehicle is made much safer.

The invention discloses a method for calculating a load coefficient of a uniform cross-section and simply-supported beam comprising near-field blast and far-field blast. The method comprises the stepsof: firstly, establishing a uniform load model of a uniform cross-section and simply-supported beam under the action of near-field blast and far-field blast, and establishing a coordinate by taking the mid-span position of the uniform cross-section and simply-supported beam as the coordinate origin, the horizontal rightward parallel beam direction as the x axis direction and the direction vertical to the x axis direction as the y axis direction; and, selecting the mid-span cross section of the uniform cross-section and simply-supported beam as an observation position, wherein constraint conditions of two end parts of the uniform cross-section and simply-supported beam are same, solving a first-order vibration mode function by adopting Taylor's third-order substitution, selecting a typicalblast impact wave overpressure peak parameter value and an explosive equivalent, and thus, determining the blast load coefficient of the uniform cross-section and simply-supported beam comprising near-field blast and far-field blast. A uniform calculation formula obtained by the method can provide relatively accurate calculation numerical value for structural design calculation; and the design risk due to ignoring of the near-field blast in the traditional method can be reduced.

The invention discloses a method for calculating main circuit parameters of a three-level active power filter. The method comprises the following steps: carrying out equal-amplitude PARK transformation on a mathematical model under a fundamental wave rotating coordinate system of a three-phase four-wire system APF to obtain a dq coordinate system function; substituting the output current componentvalue output by the APF after symmetrical harmonic is compensated for five times into the dq coordinate system function to obtaina maximum value range of the total filter inductance after the symmetrical harmonic is compensated for five times; calculating the vector relationship of the voltage and the current to obtain an inductance value range meeting the current output capability and ripple current limitation at the same time under different direct-current bus voltages and power grid voltages; obtaining a main filtering capacitor capacitance value according to relational expressions of theresonant frequency of the LCL filter and the switching frequency and the power grid frequency; and obtaining the resistance value of the damping resistor according to the relationship between the damping resistor loss and the harmonic current flowing through the damping resistor. Accurate parameters of each component of the main circuit can be obtained under the conditions of different limit compensation currents and different power grid voltages, and the obtained parameter values have obvious effects on compensation of harmonic current and suppression of the switching frequency.

The invention relates to a determination method for potential well deep distribution of methane adsorption by coal, which relates to a method for evaluating methane reserves in a coal reservoir, due to characteristic of uneven potential well depth of methane adsorption by raw coal body, multi-measuring point adsorption measurements under adsorption pressure and different constant temperature conditions can be carried out on a block coal sample; by using a Langmuir equation based on adsorption kinetics, the adsorption rate parameter b under different constant temperature conditions and the corresponding temperature T enable fitting calculation to obtain a proportion constant bm, the methane adsorption quantity under each constant temperature condition and adsorption pressure are subjected to segment fitting, quantity of different depths of potential wells can be calculated, and a potential well distribution histogram in a certain depth scope can be drafted. The method can be used for realizing accurate calculation of methane adsorption capability under different temperature and pressure conditions on the coal body, and can be used for accurately evaluating the coal bed gas content of the coal reservoir.

The invention discloses a regional protection system based on an adaptive current protection associated factor and a method thereof, belonging to the technical field of fault diagnosis of power systems. The regional protection system comprises a data acquisition module, a protection effectiveness setting module, a protection effectiveness function generating module, a protection cooperative degree desired function generating module and a fault recognition module. The method comprises the following steps: acquiring the set value and protection action practical state of respective adaptive current protection in a protection region; computing the effectiveness of respective adaptive current protection; computing the protection cooperative degree function value of each line; computing the protection cooperative degree desired function value of each line; computing the adaptive current protection associated factor of each line; identifying a faulty line according to the adaptive current protection associated factor of each line. The regional protection system is adaptive to the change of a power grid running way, the formation of a current protection criterion and the acquisition of a protection action value independent of the synchronism of a communication system, and faults can be adjusted accurately.

The invention discloses a method for measuring the rotor copper loss caused by harmonics under the no-load condition of a variable-frequency motor. A partner-testing motor drags a tested variable-frequency motor to realize speed synchronization, a variable frequency power supply provides a voltage for the tested variable-frequency motor under a normal no-load work condition, input power, a statorvoltage, a stator current and stator end resistance at the time are recorded, and a stator copper loss value and a lossPL1 except the stator copper loss value are calculated; with an empty-slot rotoriron core, the same experiment is carried out again after assembling, so that a loss PL2 except the stator copper loss value is obtained; and a rotor copper loss Phcu2 that is caused by harmonics andcorresponds to a no-load voltage U1 of the tested variable-frequency motor is equal to a difference between the lossPL1 and the loss PL2. According to the invention, the rotor copper losses caused byharmonics are measured by dragging the rotor of the variable-frequency motor at the synchronous speed; and only harmonic induction currents instead of fundamental currents exist in the rotor guide barand the end ring, so that the pure harmonic rotor copper loss of the variable-frequency motor under the ideal no-load condition is obtained.

The invention discloses a drill bit performance evaluating method and system. The method and system are particularly suitable for steering drilling. Based on a virtual strength index principle, considering a steering drilling driving mode using a bottom power drilling tool, a drill bit rock breaking efficiency calculating method under the steering drilling mode is established, drilling bit rock breaking efficiency and footage are comprehensively balanced, the influences of drilling working conditions on the compatibility of a drill bit and a stratum are reduced to the maximum extent, and errors in drill bit performance evaluation in the prior art are corrected. By means of the scheme, the method and system have the advantages that two different driving modes including the oriented slide drilling mode and the dual-drive composite drilling mode are considered for drilling bit rotating speed, and the working characteristics of the drill bit can be more reasonably represented; under the steering drilling conditions, according to the different driving modes, virtual strength indexes are calculated for well segments in the footage of the single drill bit in a segmented mode, and the total virtual strength index calculation value in the footage of the single drill bit is more precise.

The invention discloses a method for measuring surrounding rock displacement of a deeply-buried circular tunnel based on the limit state theory. The method comprises the following steps of measuring an initial stress field p0 of a rock body; when the broken area exists, carrying out the triaxial unloading test according to the initial stress field to obtain a broken area surrounding rock unloadingcurve and a broken area outer boundary radial stress pic; calculating the radius Rc of the crushing area by using a layered summation method according to the surrounding rock unloading curve of the crushing area; according to the radial stress pic of the outer boundary of the crushing area and the radius Rc of the crushing area, calculating the radius Rp of a plastic area by using a layered summation method; calculating the displacement uC of the outer boundary of the crushing area according to the surrounding rock unloading curve of the crushing area; according to the displacement uC of theouter boundary of the broken area, calculating u0 of the maximum displacement of the tunnel wall by using a layered summation method; and calculating the displacement of the surrounding rock accordingto the u0 of the maximum displacement of the tunnel wall and the radius Rp of the plastic zone. The method is high in accuracy, complete in theory and simple in calculation.

An abnormality cause determining device that is applied to a vehicle including an electromagnetic actuator includes a storage device and an execution device. The storage device is configured to store map data which is data for defining a map. The map includes a current variable which is a variable indicating a current flowing actually in the electromagnetic actuator as an input variable and includes a cause variable which is a variable indicating a cause of an abnormality of an onboard unit including the electromagnetic actuator as an output variable. The execution device is configured to perform an acquisition process of acquiring a value of the input variable based on a detection value from a sensor which is mounted in the vehicle and a calculation process of calculating a value of the output variable by inputting the value of the input variable to the map.

The invention relates to a multi-workshop health monitoring system and method, and the system comprises an obtaining module which is used for obtaining the structure image data, the real-time operation parameter data and the remote data of a plurality of hardware devices, and a generation module which is used for generating a plurality of index parameters according to the structure image data, the real-time operation parameter data and the remote data; the acquisition module is used for acquiring data in a workshop to be monitored, the distribution module is used for distributing a weight coefficient for each index parameter, and the central control module is used for adjusting the number of the index parameters in the generation module and the weight coefficients distributed by the distribution module according to the data acquired in the acquisition module and judging the state of hardware equipment in the workshop to be monitored according to a comparison result. And the use frequency of the hardware equipment is selected according to the state of the hardware equipment, so that the calculated health degree is more in line with the actual operation state, the calculated value of the health degree of the factory is more accurate, efficacy management on the hardware equipment according to the health value is facilitated, and the management efficiency is improved.