38results about How to "Big error" patented technology

The invention belongs to but not limited to the technical field of animal husbandry statistics, and particularly relates to an alpine meadow yak number calculation method and system based on an unmanned aerial vehicle image, and the method comprises the steps: S1, employing an unmanned aerial vehicle to shoot an orthoimage of a sample plot, and carrying out the statistics of the yak number; s2, splicing the shot images by using Pix4D software, screening a proper sample plot, and respectively counting the quantity of wet cow dung and the quantity of dry cow dung in a visual interpretation mode; and S3, carrying out linear fitting on the obtained data by using Origin 2024b, so as to obtain three relation curves. According to the method for estimating the number of the yaks through statistics of the number of the cow dung in the unmanned aerial vehicle image, the workload of data collection is greatly reduced, and the limitation that the number of the yaks cannot be obtained when the yaks are not grazed in the grassland is avoided. According to the invention, the data acquisition frequency of experimenters is effectively reduced, and the research cost is reduced.

The invention provides a multi-sensing-value double-tipping-bucket type rainfall sensor, and relates to the field of rainfall sensors. The multi-sensing-value double-tipping-bucket type rainfall sensor comprises a collecting device, a supporting device, a first measuring device and a second measuring device, the collecting device is arranged at the top end of the supporting device, the second measuring device is arranged at the top end of the supporting device, the collecting device comprises a shell, a water bearing device is arranged at the position, close to the upper portion, of the inner side wall of the shell, and the water bearing device is arranged on the inner side wall of the shell. The bottom end of the inner side wall of the water receiver is rotationally connected with a filter screen, and the side wall of the bottom end of the filter screen penetrates through the middle of the bottom end of the inner side wall of the water receiver and is in threaded connection with a cleaning and detaching nut. By arranging the collecting device, equipment blockage and influence on detection data caused by long-time use of the water receiver are avoided, by arranging the supporting device, it is guaranteed that the whole device is in an absolute horizontal state before detection, the first measuring device can play a good role in buffering rainwater, the measurement resolution is improved, and by arranging the second measuring device, the detection accuracy is improved. And the measurement precision under the condition of heavy rainfall (heavy rainfall intensity) is effectively improved.

The invention discloses a line loss determination method and device of a transformer area, a processor and electronic equipment. The method comprises the steps that a target label is determined from at least one label of a transformer area, and the label is used for representing attributes of the transformer area in the electric energy consumption process in a historical time period; in the interval range of the target label, determining parameters of the target label; based on the parameters, determining a line loss threshold of the transformer area in a sub-historical period from at least one piece of candidate line loss data of the transformer area, the historical period including the sub-historical period, and the candidate line loss data being used for representing line loss data except the abnormal line loss data in the line loss data in the historical period; the line loss data is used for representing the loss amount of the electric energy in the transformer area, and the line loss threshold value is used for representing the transmission rate of the electric energy in the transformer area. The technical problem that the accuracy of determining the line loss of the transformer area is low is solved.

The present invention discloses a method for estimating blood flow velocity by transmitting sparse pulses, and specifically designs a blood flow velocity estimation method based on sparse pulses. The present invention transmits sparse pulses to obtain echo signals, and then performs autocorrelation operation and vectorization on the echo signals to obtain virtual echo signals with equivalent uniform emission and a larger number of pulses. The result of spectral estimation of the echo signals is compared with the result of spectral estimation of the virtual echo signals, and finally the value of blood flow velocity estimation is obtained. The method used in the present invention can obtain high-resolution, low-artifact blood flow velocity estimation results with a small number of pulses, which is beneficial for medical ultrasound systems to further improve the refresh rate and real-time performance of B-mode imaging.

A high-speed laser cladding wear-resistant and anti-corrosion layer production process and equipment for oil pumping polished rods, which has the following steps: 1) Sanding - grinding the part of the oil pumping polished rod to be clad on a sand grinder so that the outer circle reaches the preset diameter, while removing surface impurities and reducing surface roughness; 2) Clamping - clamping the sanded oil pumping polished rod to the polished rod bearing device; 3) Laser cladding - using a high-energy laser beam to clad the anti-corrosion and wear-resistant alloy layer on the surface of the preheated oil pumping polished rod. The present invention has a novel structure and ingenious conception. It uses an electromagnetic induction heating device to preheat the oil pumping polished rod, and then uses a high-energy laser beam to clad the alloy powder on the surface of the oil pumping polished rod to form a metallurgically bonded nickel-based alloy layer. Through the above-mentioned production process and equipment, the current situation of the traditional spray welding oil pumping polished rod production process being complicated, low powder utilization, and high equipment power consumption has been changed, the process has been simplified, costs have been saved, and it has extensive economic and social benefits.

The invention discloses an on-line pressure monitoring and automatic purging system and method for an induced draft fan of a thermal power plant. The system comprises a heat tracing pipe, a temperature controller B and an air pipe electromagnetic valve C, the heat tracing pipe is used for leading out smoke from the pressure measuring point A. A temperature controller B and an air pipe electromagnetic valve C are arranged at the tail end of the heat tracing pipe, the temperature controller B is used for measuring the temperature of the smoke in the heat tracing pipe, and the air pipe electromagnetic valve C is used for measuring the pressure of the smoke in the heat tracing pipe. The flue gas temperature and pressure in the heat tracing pipeline are respectively controlled to maintain normal levels, and pipeline blockage is prevented. The method comprises the steps that the normal temperature of flue gas in a flue is t1, and the temperature t2 of the flue gas in a heat tracing pipe is counted every 30 minutes; and if t2 is less than (t1-10) DEG C and the time exceeds 30 minutes, the heat tracing pipeline starts to heat until the temperature rises to (t1 + 10) DEG C. The problem that a pressure on-line monitoring system is prone to blockage is mainly solved.

The utility model belongs to transformer oil technical field especially relates to transformer oil level intelligent monitoring device, including transformer casing, the top of transformer casing is connected with the connecting pipe no.

The invention discloses a method for evaluating the volume change rate of foundry coke, and belongs to the technical field of foundry coke production. The method comprises the following steps: substituting volatile components and caking indexes of coal as fired into a formula Vc = 0.4435 * Vdaf + 0.1995 * G-20.1214 to obtain a predicted value of the volume change rate of foundry coke; according to the method, the complex relation between the as-fired coal index and the foundry coke volume change rate can be accurately captured, the average absolute error can be controlled within 3% through actual verification, and compared with the prior art, the accuracy is improved by 40%-60%; the problem that the volume change rate of foundry coke cannot be accurately predicted is solved.

The application discloses a lithium ion battery internal short circuit fault simulation method, comprising the following steps: S1, establishing a lithium ion battery single particle lumped parameter estimation model, and estimating the dynamics and transfer attribute parameters of a lithium ion battery to be simulated by using a control equation; S2, constructing an electrochemical-thermal coupling 3D model and setting a control equation thereof; S3, substituting the dynamics and transfer attribute parameters of the simulated lithium ion battery into the constructed electrochemical-thermal coupling 3D model, simulating the electrothermal behavior of the lithium ion battery under different fault types based on the control equation, and realizing internal short circuit fault simulation. The application solves the defects of the existing fault simulation scheme in simulation accuracy, calculation rapidity and application universality, establishes an internal short circuit fault electrochemical-thermal coupling 3D model, and provides simulation data basis for an internal short circuit fault detection method.

The invention relates to an optical system installation and adjustment technology, and provides an installation and adjustment method of a multi-path imaging system in order to solve the problems that an existing installation and adjustment method is large in error, low in precision, inconsistent in resolution ratio and the like, and the installation and adjustment method comprises the steps that the multi-path imaging system is preliminarily built according to theoretical parameters of system design; the attitude of a transmitting end primary mirror is determined through a first theodolite, a small-caliber plane mirror and a large-caliber plane mirror, and the spatial position of a transmitting end secondary mirror is adjusted through a second theodolite and a cross wire reticle, so that an image of the cross wire reticle sequentially passes through the transmitting end primary mirror and the transmitting end secondary mirror and then coincides with the center of the second theodolite; determining the spatial positions of the slit and the light source, and completing the light path adjustment of the transmitting end; a receiving end light path is adjusted according to the transmitting end light path adjusting step, then a resolution plate is installed between the transmitting end light path and the receiving end light path, the spatial position of an imaging lens is adjusted, a plurality of imaging cameras all capture the clearest image of the resolution plate, and installation and adjustment of the multi-path imaging system are completed.

The invention belongs to the technical field of flow detection, and particularly relates to an ultrasonic flow fusion method and system based on multiple modalities, and the method comprises the following steps: S100, constructing a modal number selection model in advance; s200, a first probe and a second probe are adopted to send a first transmitting signal and a second transmitting signal respectively, and a first receiving signal and a second receiving signal are collected correspondingly; s201, a corresponding mode selection number is matched in the mode number selection model; s202, at least three modes are selected from the modes according to the mode selection number, and the selected at least three modes are divided into at least two mode groups; s203, the volume flow is obtained through calculation according to the modal group; and S205, a flow mean value is calculated according to the at least two volume flows, and compared with flow measurement in a single mode, the flow measurement precision in a large-pipe-diameter scene is greatly improved.

The invention belongs to the technical field of flow detection, and particularly relates to a temperature-adaptive ultrasonic flow measurement method and system.The method comprises the steps that S101, a first probe and a second probe are adopted to send a first emission signal and a second emission signal respectively, and a first receiving signal and a second receiving signal are collected correspondingly; s102, selecting two modes from the plurality of modes; s103, respectively acquiring the forward and reverse flow time under the first mode and the second mode; s104, the volume flow is calculated according to the forward and reverse flow time in the S103; by means of the method, the temperature-adaptive ultrasonic flow measuring method capable of being applied to the large-pipe-diameter and large-flow pipeline is comprehensively provided, and the tedious temperature compensation process in the prior art is reduced.

The utility model discloses an anchor rod hole reaming device and an anchor rod trolley, and belongs to the technical field of characteristic equipment.The anchor rod hole reaming device comprises a propelling beam, a drill rod and a reaming assembly, the drill rod is arranged in the propelling direction of the propelling beam, the reaming assembly is detachably arranged on the drill rod in a sleeved mode, and the reaming assembly is arranged on the propelling beam. The drill rod is used for drilling an anchor rod hole in the tunnel wall, and the hole expanding assembly is used for expanding a hole opening of the anchor rod hole. The drill rod lifter assembly is arranged on the propelling beam, and the drill rod lifter assembly is used for limiting a drill rod; and the top block assembly is arranged at the front end of the propelling beam, and the top block assembly is used for being attached to the tunnel wall in a grabbing mode. The technical problems that when the anchor rod is in butt joint with the anchor rod hole, supporting of the anchor rod is not enough, the positioning precision is not high enough, the allowable error between the end of the anchor rod and the center of the anchor rod hole is too small, a leading-in effect is not provided for the anchor rod, the center of the end of the anchor rod does not correspond to the center of the hole, and even the anchor rod cannot be pushed can be solved.

The utility model provides a kind of machining center automatic clamping workpiece device, including base plate and automatically clamping mechanism movably set on base plate, clamping station is equipped on base plate, clamping station is equipped with multiple positioning surface for supporting and limiting workpiece, automatically clamping mechanism includes power drive assembly, force transmission mechanism and multidirectional clamping assembly;Power drive assembly movably set on base plate;Force transmission mechanism is rotatably connected on base plate, and is linked with power drive assembly;Multidirectional clamping assembly includes first clamping component and second clamping component, first clamping component is linked with force transmission mechanism, and is cooperated with one of positioning surface to realize the clamping positioning of workpiece vertical direction;Second clamping component is slidably arranged in base plate and is linked with first clamping component, and is cooperated with another one of positioning surface to realize the clamping positioning of workpiece lateral direction.The utility model realizes workpiece fast and stable automatic chucking, improves overall machining efficiency and product quality.

The invention relates to the field of endoscope abnormity diagnosis, and discloses an endoscope diagnosis system and method based on image analysis, and the method comprises the following steps: carrying out the structure participation degree evaluation of an endoscope, determining the structure, needing defect diagnosis, of the endoscope based on the structure participation degree evaluation result, surface image analysis and preprocessing are carried out on the structure, and finally defect positioning, defect analysis, defect classification and defect repair are carried out on the endoscope on the basis of analysis and preprocessing results, so that a qualified endoscope is obtained. According to the method, the defect position of the endoscope can be found through image analysis of the endoscope, the defect of the endoscope is repaired according to the type of the defect position, error increase of the endoscope in the using process is prevented, better tool service is provided for doctors in the using process, and the medical efficiency and the medical effect of the doctors can be improved.

The utility model discloses a torque control silk screen tensiometer calibration device, which relates to the technical field of torque control silk screen tensiometer calibration and comprises a device base, a detection table is arranged at the upper end of the inner side of the device base, and displacement seats are movably connected to the four ends of the inner wall of the detection table. According to the calibration device for the torque control silk screen tensiometer, when one transmission gear rotates through a servo motor, the transmission gear enables four displacement seats to move at the same time through a transmission circular ring, so that the four displacement seats pull the four ends of a torque control silk screen at the same time; the situation that the torque control silk screen is unstable or different in tensile force in the tensile force applying process, consequently, the stress needs to be continuously adjusted again in the calibration process, and the error of the measurement result is increased is effectively prevented, and one servo motor drives four displacement seats to move, so that the accuracy of the measurement result is improved. And energy consumption caused by the fact that a plurality of motors drive the displacement base to move is reduced, and the working efficiency is improved.

The present invention discloses a multifunctional logistic robot for construction sites and a method for handling trivial tasks thereof, comprising a left car and a right car of the same structure, wherein the left car is equipped with: a marking unit for drawing circular marks on the ground; a cement mixing unit, using four stirrers evenly distributed on a stirrer support plate, and the four stirrers are opened and closed by the rotation of the stirrer steering gear to form a four-claw structure; the right car is equipped with: a transport unit for transporting objects to a destination; a steel bar welding unit, using a plurality of electric push rods and grippers to realize automatic welding of steel bars; a clamping mechanism is detachably installed between the left car and the right car, and the space range of the clamping is adjusted by the joint use of a plurality of electric push rods; a cutting mechanism, by setting a motor and a screw arranged horizontally and vertically to adjust the cutting path of the cutting machine. The present invention can solve the problems of pile point marking, cement mixing, template cutting, object transport, and steel bar welding for construction sites.

The present invention relates to the technical field of intelligent detection data management of air conditioner appearance, and specifically discloses an intelligent detection data management platform for air conditioner appearance based on AI vision, the platform comprising: a position correction evaluation module, a code reader scanning module, an air conditioner appearance quality inspection module, a database and a detection accuracy evaluation module; the present invention corrects the air conditioner product whose position is not corrected through the air valve body inside the quality inspection equipment, and evaluates whether the appearance quality inspection of the air conditioner product is qualified according to the quality inspection data corresponding to each component in each detection group in each detection surface of the air conditioner product, and finally performs manual spot check on the air conditioner products with qualified appearance quality inspection, and conducts in-depth analysis on the accuracy of detection work of the detection post according to the manual spot check data, thereby reducing the complexity of quality inspection, shortening the detection time, and improving the timeliness of discovering errors or omissions in the quality inspection process, so as to help enterprises accurately understand the actual effect and existing problems of the quality inspection link.

The utility model discloses a resistance test system, comprising a light source used for emitting light to a cell to be tested; the grating is located between the imaging device and the battery piece to be detected; the grating is used for shielding part of light emitted by the light source; the grating comprises at least two gratings, and the patterns of the at least two gratings are complementary patterns; the imaging device is used for respectively acquiring at least two first gray value images of the battery piece to be detected under the condition that the at least two optical gratings shield part of light rays emitted by the light source; under the condition that the light emitted by the light source is not shielded, the imaging device is also used for acquiring a second gray value image of the battery piece to be detected; the control module is electrically connected with the imaging device and the light source, and the light source is located on one side of the imaging device. According to the utility model, the non-contact measurement of the resistance of any metalized pattern battery piece can be realized, the universality and compatibility are good, and the accuracy of the test result is improved.

The utility model relates to the technical field of wheel hub detection, and discloses a wheel hub balance detection mechanism for a balance vehicle, which comprises a workbench, the upper surface of the workbench is fixedly connected with a fixed table, the upper surface of the fixed table is provided with a groove, the surface of the workbench is fixedly connected with a motor, and the motor is fixedly connected with the fixed table. And one end of an output shaft of the motor penetrates through the upper surface of the workbench and the inner wall of the bottom of the groove to be in key connection with a tray, a sliding assembly is arranged between the tray and the groove, and a locking assembly for fixing the hub is arranged on the tray. The numerical value of the pressure borne by the pressure sensor can be visually seen from the display screen, manual calculation is not needed, a large amount of time is saved, the testing efficiency is improved, the tray can be kept in a balanced state all the time, hub deviation caused by deviation is prevented, and the hub can be conveniently and rapidly tested through the detachable threaded ring. And the threaded rods corresponding to the inner ring diameters of the hubs with different diameters are replaced to lock and fix the hubs.

The invention provides an in-situ correction roadway loose zone testing method based on a DeeplabV3 + language segmentation algorithm, and relates to the field of roadway loose zone testing, and the method comprises the following steps: drilling a hole underground, obtaining a rock core, obtaining a test drill hole, and obtaining a wave velocity-double collection time-test depth curve graph of the loose zone test drill hole by using a single-hole ultrasonic velocity measurement method; analyzing according to the wave velocity-double receiving time-test depth curve graph to obtain the longitudinal wave velocity of the original rock mass; utilizing the obtained rock core to obtain the position of a rock mass deep loose circle by combining a co-location discrimination method with a wave velocity-double receiving time-test depth curve graph; a drilling optical electron microscope method based on a DeeplabV3 + language segmentation algorithm is utilized to identify cracks and lithology data on the surface of a hole wall, and the lithology data are combined to analyze surface cracks actually influencing the surrounding rock loose circle; and the real range of the roadway surrounding rock loosening circle is given by combining the position of the rock mass deep loosening circle and the cracks and lithology of the hole wall surface. The method disclosed by the invention has certain guiding significance on supporting and optimized supporting of the roadway.

According to the specific implementation mode, a grouting sleeve is arranged at the upper end of a vertical column rib, the upper end of the grouting sleeve is open, the lower end of the vertical column rib of an upper layer prefabricated frame module unit is inserted into the grouting sleeve to achieve connection, and a top plate is of a structure with the fully-prefabricated center and the periphery laminated layer. Post-pouring holes are formed in the side faces of the beams, and shear-resistant steel bars are inserted to form connecting structures on the lower portions of the adjacent beams. Through optimization of a column vertical rib connection form, innovation of a top plate structure and improvement of a beam connection structure, the defects that in the prior art, pressure grouting operation is complex, connection construction conflicts with indoor decoration, and the connection strength between modules is poor are overcome, the connection strength of prefabricated frame module units is improved, the construction difficulty of a construction site is reduced, and the construction efficiency is improved. And the control difficulty of the connection construction quality is reduced.

The present application discloses a time synchronization method based on Beidou satellite signals and related equipment, which relates to the field of communication technology, and discloses a time synchronization method based on Beidou satellite signals, including: obtaining Beidou satellite signals; identifying spoof signals on the Beidou satellite signals through a preset anti-spoofing model to obtain a target recognition result, wherein the anti-spoofing model is obtained by training a preset model to be trained with satellite signal samples and recognition result labels; if the target recognition result is true, then based on the Beidou satellite signal, time synchronization is performed on a preset base station. The present application uses satellite signal samples and recognition result labels to train a preset model to be trained. When obtaining satellite signals, spoof signals are identified on the satellite signals through an anti-spoofing model, and the base station is time synchronized using a real satellite signal, ultimately achieving a significant improvement in the success rate of base station time synchronization.

This invention discloses a key exchange method, apparatus, and storage medium based on a modular lattice. The key exchange method includes: Party A generating a random number seed, obtaining a compressed public key, and sending it to Party B; Party B using the random number seed to obtain the compressed public key; recovering data from the received compressed public key from Party A and calculating a temporary key; processing the temporary key using a segmented signal function to obtain a signal value; using the signal value to coordinate the temporary key to obtain a shared temporary key, thereby generating a verification tag and deriving the final key; Party A recovering data from the received compressed public key from Party B, recalculating the verification tag, and comparing them; only when a match is successful, the final key is derived using the same method. This ensures the randomness of the data and the ability to detect tampering with the data received by Party A, thus achieving higher security. This invention significantly reduces the failure probability while improving security.

The present invention discloses a guide assembly and a column lifting guide mechanism, comprising: a guide rail seat; a pin shaft, one end of which is connected to the guide rail seat; a lateral sliding pad, which is connected to the other end of the pin shaft, and the surface of the lateral sliding pad opposite to the pin shaft constitutes a sliding mating surface; a rubber-coated bearing, the rubber-coated bearing jacket is connected to the pin shaft, the rubber-coated bearing is located between the guide rail seat and the lateral sliding pad, and the outer ring is spaced apart from the guide rail seat and the lateral sliding pad. The guide assembly according to the embodiment of the present invention can reduce the assembly cost and increase the service life of the guide assembly.

The utility model discloses a U-shaped steel composite beam-concrete filled steel tubular column sleeve core beam type node structure which comprises an upper steel tubular column, a lower steel tubular column, a plurality of steel beams and a connecting component, and the connecting component is in a cross shape and is provided with four connecting ends. The upper steel pipe column is located above the connecting component, and the lower end of the upper steel pipe column is fixedly connected with the upper side of the connecting component. A plurality of open grooves are formed in the top end of the lower steel pipe column and extend downwards from the top end of the lower steel pipe column in the length direction of the lower steel pipe column. The middle of the connecting component is located in the lower steel pipe column, so that the connecting end of the connecting component penetrates through the open groove of the lower steel pipe column to extend to the outer side of the lower steel pipe column, and the connecting end of the connecting component is placed in the open groove. The top end of the lower steel pipe column is fixedly connected with the lower end of the upper steel pipe column; the connecting end of the connecting component is fixedly connected with one end of the steel beam.

The invention discloses a multi-template collaborative preferential matching target tracking method, which comprises the following steps of: based on known target identification information, detecting a plurality of feature points in an area around a target, respectively establishing a feature point template and a target template, and simultaneously establishing a relative position relationship between the plurality of feature points and the target; respectively matching the feature point template established by the current frame image and the template of the target with the original image to be matched and the reduced image to be matched, preferentially selecting the matched feature point according to the matching coefficient, and obtaining the target feature point based on the fact that the relative position relationship between the feature point and the target in the actual scene is kept unchanged. The target position can be indirectly obtained through calculation according to the matched feature points; and then, according to a template matching coefficient of the target, allocating different weights to a target position obtained based on feature point matching calculation and a target position obtained based on template matching of the target, and finally obtaining a tracking position of the target and restoring the tracking position to an original image. According to the invention, the matching precision is improved.

The present application relates to a kind of magnetic valve type current transformer air gap length determination method, device, equipment and medium, the method includes determining design input parameter;Magnetic valve type electromagnetic type current transformer is constructed based on design input parameter 3D model, and air gap magnetic circuit length is scanned simulation, obtain the magnetic induction intensity parameter corresponding to each air gap magnetic circuit length;According to the magnetic induction intensity parameter corresponding to each air gap magnetic circuit length, determine the magnetic flux continuity error rate corresponding to each air gap magnetic circuit length, and establish quantization relationship according to air gap magnetic circuit length and corresponding magnetic flux continuity error rate;According to quantization relationship and constraint parameter in design input parameter, determine the maximum air gap magnetic circuit length;According to the maximum air gap magnetic circuit length and constraint parameter, determine the effective value interval of air gap magnetic circuit length.The present application has the effect of improving design precision.

This invention discloses a control method and a control device. The control method includes: entering a first execution gear stage and determining a first target gear at this stage; acquiring execution information of the previous first target gear, including target position, drive duty cycle, and actual position; if the first position difference between the preset optimal position of the first target gear in the first execution gear stage and the actual position of the previous first target gear exceeds a first execution gear threshold, correcting the target position or drive duty cycle of the current first target gear; the previous first target gear and the current first target gear are in different first execution gear stages. In this invention, when the gear shifting control accuracy of the previous gear shifting operation is low, the control accuracy of the current gear shifting operation can be improved by correcting the target position or drive duty cycle of the current first target gear, thereby increasing the success rate and accuracy of gear shifting and ensuring the driver's driving experience.

A power device temperature detection system disclosed by the present invention comprises a sampling resistor RS1, a phase voltage detection circuit and an MCU, the phase voltage detection circuit comprises a U-phase detection circuit, a V-phase detection circuit and a W-phase detection circuit, and the U-phase detection circuit, the V-phase detection circuit and the W-phase detection circuit are respectively connected with a power device. The MCU is connected with the sampling resistor RS1, the U-phase detection circuit, the V-phase detection circuit and the W-phase detection circuit, and the U-phase detection circuit, the V-phase detection circuit and the W-phase detection circuit respectively collect UAD, VAD and WAD signals of a power device and transmit the UAD, VAD and WAD signals to the MCU; and the MCU reads the variation of the UAD, VAD and WAD signals and compares the variation with the variation of the sampling signal of the sampling resistor RS1 to detect the temperature change of the corresponding U-phase / V-phase / W-phase lower bridge arm power device.