499 results about "Load resistance" patented technology

The invention discloses an on-line monitoring and early warning method for a bus capacitor of an electric driving system, and belongs to the field of electric driving systems. The electric driving system sequentially comprises an isolating circuit, a full-wave bridge rectifier, a bus capacitor bank, an inverter, an actuator and a capacitance online testing device; the capacitor online testing device comprises a relay, a load resistor, a voltage acquisition module, a current acquisition module and a master control calculation unit. When the electric drive system is idle, a load resistor is connected to construct a test path, and current and voltage signals are collected; disconnecting a test path, constructing a degradation characterization quantity of multi-index information fusion through time-frequency domain feature extraction, and constructing an equal-length time interval sequence degradation curve; and the TCN-BRU-GRU combined prediction model carries out trend feature learning and training on the degradation curve. According to the method, waveform fitting and local and global data feature capturing of non-equal-interval time sampling are achieved, trend prediction of bus capacitor performance degradation is achieved, early warning is conducted before failure of the bus capacitor, and safe and reliable operation of an electric drive system is guaranteed.

The present application relates to a method and apparatus for controlling a wireless electrical energy transmission system, and a computer device. The method comprises: determining a real-time load resistance of a wireless electrical energy transmission system, and obtaining a trained value table, the trained value table comprising a sample load resistor, a sample primary resonant capacitor, and a sample value of correspondence between each sample load resistor and each sample primary resonant capacitor; in the trained value table, determining a real-time primary resonant capacitor of the wireless electrical energy transmission system on the basis of the real-time load resistance and the sample value; and controlling the wireless electrical energy transmission system on the basis of the real-time primary resonant capacitor. By adopting the present method, the convenience of control can be improved.

The utility model discloses a miniaturized image rejection frequency mixing circuit, which comprises two passive double-balanced frequency mixers, a local oscillator bridge, a phase shift circuit and a power divider, the first input ends of the first passive double-balanced mixer and the second passive double-balanced mixer are connected with an external antenna; the second input end of the first passive double-balanced mixer is connected with the first output end of the local oscillator bridge, the second input end of the second passive double-balanced mixer is connected with the second output end of the local oscillator bridge, and the output end of the first passive double-balanced mixer is connected with the input end of the phase shift circuit. The output end of the second passive double-balanced mixer is connected with the second input end of the power divider; the isolation end of the local oscillator bridge is connected with the load resistor, and the input end of the local oscillator bridge is connected with the frequency source; the output end of the phase shift circuit is connected with the first input end of the power divider, and the output end of the power divider is connected with an external circuit. According to the utility model, the size of the image rejection mixer can be obviously reduced, and miniaturization design of a radar receiver is facilitated.

The invention discloses a three-phase wireless electric energy and signal reverse cooperative transmission system and a parameter design method thereof. The system comprises a direct-current power supply, a three-phase high-frequency inverter circuit, a three-phase primary side compensation capacitor, a three-phase secondary side compensation capacitor, a three-phase primary and secondary side magnetic coupling coil, a signal transmission channel network, a signal modulation-demodulation circuit network, an encoder, a decoder, a three-phase rectification filter circuit, a filter capacitor and a load resistor. The signal transmission channel networks respectively comprise three signal injection networks and three signal separation transmission channel networks; each signal injection network comprises a secondary side signal injection transformer, a secondary side injection signal resonant capacitor and a discharge resistor; and each signal separation transmission channel network comprises a primary side signal pickup transformer, an extraction signal resonant capacitor, a wave blocking network inductor, a wave blocking network capacitor and a sampling resistor. According to the invention, three-phase wireless energy and information parallel reverse transmission is realized, and the signal transmission rate is effectively improved while stable and efficient electric energy transmission is ensured.

The invention provides an electric bicycle AC charging pile load short circuit detection method and system, and is applied to the technical field of charging pile load detection, and the method comprises the steps: switching on a target switch in response to the detection of the insertion of a charger plug; obtaining the first detection voltage, the first detection current and the first detection active power after preprocessing through a metering chip, and switching off a target switch; determining a first detection power factor of the charging pile based on the first detection voltage, the first detection current and the first detection active power; determining a first detection load resistance of the charging pile based on the first detection voltage and the first detection current; based on the first detection power factor and the first detection load resistance, the load short-circuit state of the charging pile is determined, and the load short-circuit state comprises a normal load and a short-circuit load. According to the invention, the stability and reliability of the short-circuit detection result can be improved.

The utility model discloses a calibration device for a track circuit dynamic detection system, and relates to the technical field of track circuit dynamic detection. The device comprises a signal source module, a power amplifier, a load resistor and an ampere meter, the controller outputs a control signal to the signal generator; the signal generator outputs a current signal to the gain regulator based on the control signal; the gain regulator outputs the current signal after gain regulation to the power amplifier based on the current signal; the power amplifier outputs an amplified current signal to the load resistor based on the current signal after gain adjustment; according to the utility model, the precision and the stability of the output current signal can be improved, and the stability, the accuracy and the efficiency of the calibration of the track circuit dynamic detection system can be improved.

The utility model discloses a multi-range current acquisition circuit, which comprises a load current acquisition circuit and a current bypass circuit, the load current acquisition circuit is connected in series between a power supply and a load resistor RX, and the current bypass circuit is connected in parallel with one side of the load current acquisition circuit. According to the utility model, the current bypass circuit is designed to be connected in parallel with one side of the load current acquisition circuit, so that current acquisition is not influenced after normal switching of the load current acquisition circuit, and a new current path can be provided when the acquisition circuit is not switched so as to ensure that the load at the output end can work normally.

The invention provides a PT symmetry-based hybrid coupling wireless power transmission system with controllable output power. The output power can be adjusted while the high anti-offset characteristic is maintained. In the system, the stable output of the system when a coupling mechanism deviates is realized by enabling the system to be in a PT symmetrical state, and meanwhile, the power and efficiency of the stable output of the system are changed by changing the ratio of the reciprocal of series inductors in an LL type compensation network of a receiving end to the sum of the reciprocals of the two inductors. Compared with a common hybrid coupling wireless power transmission system, the hybrid coupling wireless power transmission system has the advantage that the output power and efficiency can be adjusted under the conditions that the system keeps high offset resistance and the load resistance and the input voltage of the system are not changed.

The invention discloses a rapid soft start control method and device for a switching power supply. The method comprises the following steps: determining a target voltage output by a soft start preprocessing circuit in a steady state according to a preset standard voltage, a preset standard current and a load resistance value of a resistive load; determining a target duty ratio corresponding to a switching tube of the soft start preprocessing circuit in a steady state according to the target voltage and a preset input voltage of the switching power supply; a first control signal is sent to the pulse width modulation circuit, and the duty ratio of the switching tube is adjusted to the maximum duty ratio; monitoring that the real-time output voltage of the soft start preprocessing circuit is increased to the target voltage through a voltage sampling circuit; and a second control signal is sent to the pulse width modulation circuit, and the duty ratio of the switching tube is adjusted from the maximum duty ratio to the target duty ratio, so that rapid soft start of the switching power supply is realized and a steady state is reached. According to the invention, the soft start time of the switching power supply can be obviously shortened, and the switching power supply can rapidly reach a stable working state after soft start.

The invention relates to the technical field of output control, in particular to a constant power control method, device and equipment based on COT and a storage medium, according to the method, fixed turn-on time is combined with dynamic turn-off time adjustment, the conciseness of COT control is reserved, accurate control over output power is achieved, and the control efficiency is improved. The influence of interference factors such as battery voltage drop and load abrupt change on constant power output can be effectively counteracted; specifically, a multi-path output synchronous opening design is adopted, and unified turn-off time adjustment logic is combined, namely, the turn-off time of a (k + 1) th period is calculated according to the total duration of a target period, so that an asynchronous turn-off condition caused by parameter differences of all channels is avoided, and the voltage rise deviation generated by load changes of a later turn-off channel is reduced; real-time output voltage and load resistance are respectively sampled in one period, battery voltage fluctuation and load change are monitored in real time, and error accumulation caused by the fact that a measured value in the current period is extended to the next period to be adjusted is avoided.

A touch display module comprises a first electromagnetic touch signal loop and a second electromagnetic touch signal loop, the first electromagnetic touch signal loop and the second electromagnetic touch signal loop generate a first induction current and a second induction current, and the length of the first electromagnetic touch signal loop and the length of the second electromagnetic touch signal loop are small. The overall time length of one-time point reporting can be shortened, and the load resistance of the first electromagnetic touch signal loop and the load resistance of the second electromagnetic touch signal loop are small. Under the condition that the load resistance is reduced, the first driving current and the second driving current are large, the electromagnetic induction potential of the electromagnetic pen is large, the first induction current and the second induction current are large, the strength of a touch induction signal can be improved, the point reporting precision of a screen is high, the charging time of the electromagnetic pen can be shortened, and the user experience is improved. And the touch effect of the electromagnetic pen is relatively good. The invention further provides a display device comprising the touch display module.

The invention relates to the technical field of amplifiers, in particular to a variable gain amplifier with a wide linear gain range and a working method, and the variable gain amplifier comprises the steps that a linear gain generation circuit receives a differential input signal and provides gain-adjustable differential output based on linear control voltage; the linear gain generation circuit comprises at least one stage of variable gain unit which comprises differential input pair transistors MN1 and MN2. The load resistor elements R1 and R2 are connected between the power supply voltage VDD and the drain electrodes of the differential input pair transistors MN1 and MN2; the tail current source MN3 provides bias current for the differential input pair transistors MN1 and MN2; the active load network is connected between the drain electrodes of the differential input pair transistors MN1 and MN2 and the ground; the active load network comprises a control tube MN8, the control tube MN8 works in a sub-threshold region, a grid electrode receives linear control voltage, equivalent impedance of the active load network is enabled to be in exponential change along with the linear control voltage through exponential I-V characteristics, and dB linear gain adjustment of the variable gain unit is achieved.

The invention relates to the technical field of testing and application of power semiconductors, in particular to a SiC MOSFET gate oxide reliability testing device and method, and the device is provided with a high-voltage direct-current voltage power supply, an auxiliary direct-current voltage source, a signal generation device, a half-bridge testing circuit, a gate drive circuit, a load inductor, a load resistor and measuring equipment. According to the method, the stress time required for evaluating the reliability of the device can be remarkably shortened, meanwhile, the threshold voltage drift characteristics of the device under different drain-source voltage stresses can be more accurately described, compared with a traditional static bias and grid switch stress test method, the influence of dynamic drain-source voltage and current is effectively introduced, the accuracy of a model test result is improved, and the reliability of the device is improved. The method has a certain application value for evaluating the reliability of the gate oxide layer of the SiC MOSFET.

The invention provides a static frequency divider with adjustable self-resonant frequency and a clock circuit, and relates to the technical field of circuits, the frequency divider comprises a master latch and a slave latch; each of the master latch and the slave latch comprises a current source, an adjustable resistor unit, a differential amplification pair, a cross coupling pair and a load resistor pair; the current source is connected with the first current branch and the second current branch, the first current branch is connected with the load resistor pair through the differential amplification pair, the second current branch is connected with the load resistor pair through the cross coupling pair, the first current branch is provided with a first switching tube, and the second current branch is provided with a second switching tube and an adjustable resistor unit which are connected in series. Thus, the adjustable resistor unit is configured on the second current branch, association between the resistance value of the adjustable resistor unit and the frequency of the frequency divider is established, a hardware basis is provided for frequency adjustability, and frequency requirements of different scenes are met by adjusting the resistance value of the adjustable resistor unit and adjusting the self-resonant frequency of the frequency divider.

The utility model belongs to the technical field of test equipment, and discloses portable alternating current charging pile test equipment, which comprises an alternating current charging pile tester, and a charging gun socket, a test circuit board and a load resistor are arranged on one side in the alternating current charging pile tester. The test circuit board comprises an AD sampling circuit and an ARM processor electrically connected with the AD sampling circuit. The AD sampling circuit is composed of a clamp voltage circuit, a measurement reference circuit, an LN voltage sampling circuit, an LN current sampling circuit, a CP voltage sampling circuit, a PWM waveform sampling circuit, a CC resistance sampling circuit, an AD data acquisition circuit and a test process control circuit. According to the utility model, all functions of testing the alternating current charging pile can be integrated on one testing device, the functions are comprehensive, the device is convenient to carry, and the device can be used for testing on a factory production line, can also be carried about, and is used for testing the charging pile on a charging pile working site.

The application provides a constant current source circuit, which comprises a three-terminal adjustable voltage reference chip, an operational amplifier and a power supply end, a first resistor, an NMOS tube, a load resistor and a power supply ground end connected in series; the three-terminal adjustable voltage reference chip is connected with the power supply end and the operational amplifier; the NMOS tube comprises a D pole, an S pole and a G pole; the NMOS tube is connected with the first resistor through the D pole, connected with the load resistor through the S pole and connected with the output end of the operational amplifier through the G pole; the current flowing through the load resistor is controlled by controlling the voltage between the S pole and the G pole; and the constant control of the current flowing through the load resistor by the NMOS tube is realized. The constant current source circuit provided by the application not only does not generate common-mode voltage, but also improves the constant current source output current and the stability of the constant current source.

This application belongs to the field of aero-engine design, and is a perforated sound-absorbing panel layering structure, including a transverse layering member and a longitudinal layering member. The transverse layering member and the longitudinal layering member are integrally arranged. The transverse layering member includes a first transverse plate and a first longitudinal plate, and multiple groups of the first transverse plates and the first longitudinal plates form an S-shaped structure. The longitudinal layering member includes a second transverse plate and a second longitudinal plate, and multiple groups of the second transverse plates and the second longitudinal plates form an S-shaped structure. By providing the integrally arranged transverse layering member and the longitudinal layering member, and the transverse layering member and the longitudinal layering member cross each other structurally to form a spatial circuit structure, and a three-dimensional load-bearing structure is formed through the repeated overlapping of the integral body, thereby improving the anti-fatigue performance of the whole and the local parts. In the face of loads in any direction, the transverse layering member and the longitudinal layering member will be stressed simultaneously, so as to disperse the loads to various positions of the sound-absorbing panel. While preventing interlayer delamination, the overall performance is improved, and the load resistance and deformation resistance are greatly improved.

The present invention provides a strong-coupling charging magnetic coupling mechanism and its load identification method, comprising a transmitting coil, a receiving coil, and a ferrite. The coupling coefficient between the transmitting coil and the receiving coil is constant. The transmitting side is provided with a capacitor and an inductor, the inductor being obtained by short-circuiting the primary. The receiving side has a load. By resonating the capacitor and inductor to achieve a constant voltage output independent of the load, the load resistance can be calculated. Accurate load identification can better meet the requirements of the control strategy.

This invention discloses a method for optimizing the geometric parameters of a thermoelectric arm in a thermoelectric power generation system, relating to the field of thermoelectric power generation. The method includes: constructing a three-dimensional steady-state multiphysics coupled model of the thermoelectric power generation system; incorporating the height and cross-sectional area of ​​the thermoelectric arm as core geometric parameters to be optimized; and configuring the Seebeck coefficient, electrical conductivity, and thermal conductivity parameters corresponding to the thermoelectric material; setting boundary conditions for the model, including the target temperature at the hot end of the thermoelectric arm, the fluid velocity boundary corresponding to the cold end heat dissipation, and the system load resistance boundary, to ensure the model remains consistent with the actual working scenario. This invention improves model adaptation accuracy by constructing a multiphysics coupled model that fits the actual working conditions and dynamically adjusting material-related parameters. Combined with a parameterized scanning strategy with dynamic step sizes, it improves scanning efficiency while ensuring optimization effectiveness. The dual-objective optimization based on dynamic weights can flexibly adapt to different power supply requirements.

The application provides an ATE device source board channel parallel test system, which comprises a load unit, a VI source board and a plurality of measured load channels, the VI source board is connected with the plurality of measured load channels through signal ports, the load unit selects single-channel independent load or multi-channel parallel load according to a control signal, switches load resistance value according to the control signal, and outputs a load end current signal, a plurality of current-voltage conversion units, input ends of the plurality of current-voltage conversion units are connected with the plurality of measured load channels respectively, and the plurality of current-voltage conversion units are used for converting the load end current signal into a load end voltage signal, a multi-channel voltage measurement unit, the multi-channel voltage measurement unit selects one or more voltage signals according to a control signal, and outputs after conditioning the single-channel signal or performing summation operation on the multi-channel signal, and a control unit, the control unit outputs the control signal and receives measurement data from the multi-channel voltage measurement unit, and the control signal is used for controlling channel selection, load switching and measurement path selection.

Circuit arrangement (1), comprising: - N electrical energy sources (2a-c), each configured to provide electrical energy with a predetermined value of a physical quantity at a terminal (4a-c) of the energy source (2a-c) in a normal operating state; - a detection device (5) having an analog input (6) and an output (7) and configured to provide at the output (7) a detection signal (8) which depends on a voltage applied at the analog input (6); - a load resistor (11); - (N-1) resistors of the first kind (12a, b), wherein the first resistor of the first kind (12a) is connected to the load resistor (11) and the (N-1)th resistor of the first kind (12b) is connected to the analog input (6) of the detection device (5); - N resistors of the second kind (13a-c), wherein the first resistor of the second kind (13a) connects the terminal of the first power source (2a) to a first circuit node (14a) between the load resistor (11) and the first resistor of the first kind (12a), wherein the Nth resistor of the second kind (13c) has an Nth circuit node (14c) with the (N-1)th resistor of the first kind (12b) and is connected to the analog input (6); and - an evaluation device (17) which is designed to determine a fault operating state of at least one of the energy sources (2a-c).

A stall detection system is provided that determines if a glass slide in motion during an automated process is at risk for being damaged and stops motion in the event of an unacceptable risk of damage. The system includes one or more motors configured to move a glass slide (directly or indirectly). The motors are configured to generate a load resistance value. The system includes one or more processors that monitor the load resistance value of a motor during motion and compares the load resistance value to a predetermined threshold resistance value to determine the risk of a glass slide being damaged. The predetermined threshold resistance value may correspond to a risk of slide breakage in response to a force applied to any surface of the slide, or a risk of losing a controlling grip on a slide rack, or a risk of a motor skipping a motor step.

The utility model relates to the technical field of converters, in particular to a DAB converter adopting a bidirectional switch tap inductor, which comprises a primary side structure and a secondary side structure. The primary side structure comprises a direct current power supply Uin, an input capacitor Cin, a first power switch tube S1, a second power switch tube S2, a third power switch tube S3, a fourth power switch tube S4, a high-frequency inductor L, an excitation inductor Lm, a bidirectional switch tap inductor Lt and a transformer T; and the secondary side structure comprises a load resistor RL, an output capacitor Cout, a fifth power switch tube S5, a sixth power switch tube S6, a seventh power switch tube S7 and an eighth power switch tube S8. According to the converter, equivalent magnetization inductance is changed through bidirectional switch tap inductance, equivalent magnetization current is increased, zero-voltage switching-on is realized, switching loss is reduced, and the conversion efficiency is improved. When the input voltage and the output load are suddenly changed, good dynamic response capability is maintained, and zero-voltage switching operation is realized in a wide load and wide battery voltage change range.

The invention discloses a detection circuit and a detection method of an intelligent power module, the detection circuit comprises a power supply module, the intelligent power module, a microcontroller unit, an inductive load and a comparator, a first voltage dividing unit is electrically connected with the intelligent power module, a second voltage dividing unit is electrically connected with the microcontroller unit, and the microcontroller unit is electrically connected with the inductive load. The microcontroller unit is electrically connected with the intelligent power module; the microcontroller unit comprises an analog input port, an over-current signal port and a digital-to-analog converter port, the intelligent power module comprises a first alternating current output port, and the comparator comprises a positive input port, a negative input port and an output port; the analog input port is connected with the load resistor, and the first AC output port is connected with the sampling resistor; the positive input port is connected with the port of the digital-to-analog converter, the negative input port is connected with the first alternating current output port, and the output port of the comparator is connected with the overcurrent signal port. The structure of the invention can accurately determine whether the intelligent power module is over-current.

The utility model relates to the technical field of brushless motor controllers, and discloses a controller load pressure detection system, which comprises a DC power supply, a controller to be detected, an instrument box, a motor dragging jig and a load resistance box, the instrument box, the motor dragging jig and the load resistance box are connected in sequence, and the DC power supply, the controller to be tested and the motor dragging jig are connected in sequence. A controller is connected to test equipment, the controller to be tested is started to enable an active motor (a brushless motor I) to start rotating, an operator operates a load resistance box according to an operation instruction to control the access of a load resistor, different loads are applied to a controller-motor system, and three indicating instruments of current, rotating speed and positive and negative rotation are observed to judge whether a product is qualified or not; and the instrument box, the motor dragging jig and the load resistance box of the detection system are integrated and independent from one another, so that the station movement of a production line and the replacement of the controller to be detected are facilitated, and the overall utilization rate of equipment is improved.

The invention discloses a load isolation type power supply module aging device and a design method thereof, and belongs to the field of aging tests. The clamp plate and the load plate are separately designed, and the clamp plate is in butt joint with the applicable load plate through the golden fingers, so that the flexibility of the matching plate is ensured, the design time and the purchase cost are reduced, and the test efficiency is improved. According to the invention, the influence of load resistor heating on the power module circuit is effectively reduced, and the accuracy and safety of module circuit test are guaranteed; aiming at the performance of a module circuit, compatibility design is carried out on different output paths of the same package, so that the burn-in test can be carried out by using the same board during single-path output or double-path output, and the reuse rate of the clamp board is improved. The load board simultaneously comprises a state monitoring module, has the functions of monitoring output voltage, alarming abnormity and storing, and ensures high reliability of the test.

The invention discloses an anti-parameter disturbance bidirectional converter non-linear control method and system, and the method comprises the following steps: building a three-order non-linear dynamic model of a three-phase voltage source converter, defining the reciprocal 1 / Rc of an AC side resistor R and a DC side load resistor in the non-linear dynamic model as an unknown parameter, and calculating the parameter disturbance of the three-order non-linear dynamic model; obtaining a system dynamic equation with parameter uncertainty of the three-phase voltage source converter; designing a state transformation function, linearizing a system dynamic equation, and mapping a state variable x; s30, a tracking error variable is defined as a difference value between the converted state variable and a reference track of the state variable, and the difference value is used for quantifying the deviation between the actual state and the expected state of the system; defining and designing a parameter updating law of the three estimated values, and calculating and updating unknown parameters on line according to the tracking error variable; and designing and calculating a control input law based on the tracking error variable and the three estimated values, and proving the asymptotic stability of the closed-loop system through a Lyapunov function.

The invention relates to the technical field of power supply circuits, and discloses a point-to-point high-voltage POC power supply circuit control method. According to the method, a power supply end and a power receiving end are included, the power supply end is connected with the power receiving end through a coaxial cable, and the power supply end is provided with a control logic device U1, a high-voltage power supply switch MOS1, a pulse detection switch MOS4, a graded pulse voltage detection resistor R1 and a power supply current and voltage detection resistor R2. The power receiving end is provided with an adjustable time interval pulse generation device U2, a pulse control circuit and a load resistor; a power supply link is established through a low-voltage pulse detection mechanism, a high-voltage power supply mode is switched after a power receiving end equipment type and power supply parameters are determined through negotiation, and overcurrent and overvoltage protection is realized at the same time. According to the application, the POC circuit power supply capability is increased, POC power supply protection is provided, the private protocol is added to negotiate and control the power supply power, and simple grading can be matched with various types of power equipment.

The present invention relates to the field of integrated circuit technology, and more particularly to an LVDS transmitter with slew control. The present invention utilizes the characteristics of resistor and capacitor delay to output a portion of the data signal output by the LVDS circuit after a delay controlled by slew control resistors (RD1 and RD2) and the parasitic capacitance of the gate of the switch tube (M3 and M4). This process absorbs the external load resistor R L The reflection of the output signal (OUTN and OUTP) is then controlled to control the voltage swing of the output signal. On the one hand, the introduction of the slew control circuit does not increase the extra power consumption of the circuit. On the other hand, the introduction of the slew control circuit can improve the ringing phenomenon of the signal at the inversion point. Secondly, due to the use of a much larger than R L RCM1 and RCM2 thus avoid increasing the current flowing through the internal matching resistor, thereby reducing the power consumption of the transmitter. Ultimately, the present invention solves the ringing phenomenon while reducing the power consumption of the LVDS transmitter.

The invention provides a load resistance value detection circuit, method and device and a storage medium, the load resistance value detection circuit comprises a battery unit, a control unit and a switching device, and the switching device is electrically connected with the battery unit, the first end of the control unit and a heating wire of an electronic atomization device. The second end of the control unit is electrically connected with the battery unit, and the third end of the control unit is electrically connected to the common connection end of the switching device and the heating wire. According to the application, the control unit samples the voltage of the battery unit and the heating wire to obtain a first sampling voltage set and a second sampling voltage set; the resistance value of the heating wire can be calculated according to the first sampling voltage set, the second sampling voltage set and the internal resistance value of the switching device, so that the resistance value detection function of the heating wire can be completed on the basis of reducing the electronic material cost, and manpower and equipment investment cost are effectively saved.