Programmable resistor device based on resistor series connection and dynamic combination and control method

Abstract

The invention relates to the technical field of electronic measurement, and discloses a programmable resistor device based on resistor series connection and dynamic combination and a control method, the programmable resistor device comprises a resistor array module, a precision compensation module, a switch switching module, a control and calculation module and an external interface module; wherein the resistor array module is provided with a plurality of gears which are formed by connecting gear nominal values in series in a preset multiplying power relation; the precision compensation module is formed by connecting a plurality of compensation resistors in series, the switch switching module comprises a plurality of high-voltage relays; each resistor of the resistor array module and the precision compensation module is connected with one high-voltage relay in parallel; and the control and calculation module is used for realizing resistor pairing and synthesis, precision compensation control, relay driving and control and output value calibration and display functions. The resistor array can generate standard resistors covering any resistance within the design range of the resistor array through programming, all reference resistors are fully utilized, and an independent resistor does not need to be prepared for each fixed gear.

Description

Technical Field

[0001] This invention relates to the field of electronic measurement technology, and more specifically, to a standard resistance generating device for high-accuracy metrology scenarios such as electrical equipment calibration, insulation resistance tester calibration, and high-precision impedance measurement system calibration. In particular, it relates to a programmable standard resistance device that can achieve a wide range, high precision, and controllable cost. Background Technology

[0002] In the fields of electrical measurement, equipment calibration, and metrology, high-precision standard resistors are crucial reference devices. For example, the calibration of insulation resistance testers requires a range of high-precision standard resistors with resistance values ​​from 0.1MΩ to 1000MΩ or even higher. Traditional solutions typically equip each range with an independent, precisely selected, and aged high-precision resistor. These resistors, especially high-value resistors (such as 100MΩ and 1000MΩ), must simultaneously meet the requirements of high stability, low temperature coefficient, and accuracy as high as 0.1% or 0.2%, which involves complex manufacturing processes and extremely high costs.

[0003] The existing technology mainly faces the following two prominent challenges: First, the cost is high: a single high-resistance standard resistor with an accuracy of 0.2% is expensive. If it is necessary to cover the full range from 0.1MΩ to 1000MΩ, dozens of precision resistors with different resistance values ​​need to be prepared, which causes the equipment cost to rise sharply.

[0004] Secondly, there is a waste of resources and a lack of flexibility: each resistor in a range is an independent device and cannot be reused. When only some ranges are used, other high-value resistors are idle, resulting in low utilization. In addition, if one resistor fails, the entire standard resistor module for that specific range must be replaced, which is inconvenient and uneconomical to maintain.

[0005] While some existing technologies employ resistor combination schemes, these are mostly simple binary range splicing, achieving fixed resistance value superposition solely through relay switching. They lack both high-precision measurement and calibration of individual resistors and a complementary combination algorithm, resulting in the combined resistor's accuracy being equivalent to that of a single resistor, failing to meet the high-accuracy measurement requirements of 0.1%–0.2%. Furthermore, these schemes lack independent accuracy compensation modules, unable to correct minute deviations in high-resistance synthesis scenarios, thus limiting their practicality. Additionally, some combination schemes fail to consider the impact of relay contact resistance and lead resistance on high-resistance synthesis accuracy, easily introducing additional errors in micro-deviation compensation scenarios, further reducing the scheme's reliability. Therefore, there is an urgent need for a high-precision programmable standard resistor device capable of achieving wide-range, high-precision resistance output at a lower cost.

[0006] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0007] To address the problems in related technologies, this invention proposes a programmable resistor device and control method based on resistor series connection and dynamic combination, in order to overcome the aforementioned technical problems existing in the prior art.

[0008] Therefore, the specific technical solution adopted by the present invention is as follows: According to one aspect of the present invention, a programmable resistor device based on resistor series and dynamic combination is provided, comprising: a resistor array module, a precision compensation module, a switch switching module, a control and calculation module, and an external interface module; The resistor array module has several ranges connected in series with the nominal values ​​of the ranges in a preset ratio relationship. Each range is composed of several reference resistors connected in series. The output of the resistor array module is connected in series with the input of the precision compensation module. The precision compensation module is composed of several compensation resistors with binary resistance values ​​connected in series. The switching module includes several high-voltage relays. Each resistor in the resistor array module and the accuracy compensation module is connected in parallel with a high-voltage relay. At the same time, each resistor is integrated with a temperature sensor to further ensure the thermal stability of the resistor through temperature compensation. The signal output terminal of the control and calculation module is electrically connected to the control terminal of the switch switching module. The control and calculation module uses a microcontroller as the core processor and has a built-in AD acquisition module and temperature compensation module to realize resistor pairing and synthesis, precision compensation control, relay drive and control, and output value calibration and display functions. At the same time, the control and calculation module is electrically connected to the temperature sensor built into the resistor array module and the precision compensation module to collect temperature data and perform temperature drift compensation. The resistor array module provides a basic resistance value through a combination of multi-level reference resistors. The accuracy compensation module corrects deviations with binary distributed compensation resistors. The switch switching module dynamically selects the corresponding reference resistor and compensation resistor through a high-voltage relay and connects them in series to the circuit to output a standard resistance value that meets the requirements.

[0009] Preferably, the resistor array module consists of several ranges connected in series, with the nominal value of each range being a factor of 10. Each gear position consists of 9 or 10 reference resistors of the nominal value of that gear position connected in series. The lowest gear position has 10 reference resistors, and the other gear positions have 9 reference resistors.

[0010] Preferably, all reference resistors are metal film resistors or alloy resistors, and each reference resistor is equipped with a temperature sensor for real-time acquisition of resistance temperature data.

[0011] Preferably, the resistor array module has at least one of the following settings: 0.1MΩ, 1MΩ, 10MΩ, 100MΩ, and 1000MΩ.

[0012] Preferably, the accuracy of the compensation resistor in the accuracy compensation module is 1% or 2%, and the resistance value of the compensation resistor is less than the combined resistance value of the resistor array module, including at least one of 100Ω, 200Ω, 400Ω, 800Ω, 1kΩ, 2kΩ, 4kΩ, 8kΩ, 10kΩ, and 20kΩ.

[0013] Preferably, the high-voltage relay is a magnetically latched high-voltage relay with a contact resistance ≤10mΩ and a withstand voltage ≥2kV.

[0014] Preferably, the external interface module communicates bidirectionally with the control and computing module, and the external interface module includes an RS485 interface, an Ethernet interface, and a touch screen interface; The external interface module's RS485 and Ethernet interfaces are used to communicate with the host computer, receive the user's target resistance setting instructions, and provide feedback on status information; the touch screen interface is used for local operation, supporting target resistance setting, device status viewing, and calibration record querying.

[0015] According to another aspect of the present invention, a control method for a programmable resistor device based on resistor series connection and dynamic combination is also provided, the method comprising: The actual resistance value of each reference resistor, the contact resistance and lead resistance of each high-voltage relay are measured and stored using measuring equipment. At the same time, the resistance value change data of the reference resistor at different temperatures are recorded, and a temperature-resistance drift curve database is established based on the resistance value change data. The target resistance value input by the user is received through an external interface module; A combined optimization strategy is formed by combining greedy strategy, deviation compensation optimization and temperature drift compensation strategy. The combined optimization strategy is used to select resistor combinations from the real value database of resistor array to obtain the corrected composite resistance value. The deviation between the corrected combined resistance and the target resistance is calculated. Based on the magnitude and direction of the deviation, a compensation resistor with the corresponding resistance value is selected from the accuracy compensation module and connected to the circuit. At the same time, the influence of the high-voltage relay contact resistance and lead resistance is deducted during the compensation process. Based on the resistor combination and compensation scheme, a drive signal is generated to control the corresponding high-voltage relay group to operate. The selected reference resistor and compensation resistor are connected in series to the circuit, and the unselected resistor is short-circuited by the high-voltage relay connected in parallel with it. The composite value is calculated based on the actual resistance value of the stored reference resistor, the corrected composite resistance value, the compensation resistor value, and the corrected values ​​of the relay and lead resistance. The composite value is then used as the standard output value and displayed through an external interface module.

[0016] Preferably, a combined optimization strategy is formed by combining a greedy strategy, a deviation compensation optimization strategy, and a temperature drift compensation strategy. This combined optimization strategy is used to select resistor combinations from the real value database of the resistor array, resulting in corrected composite resistance values ​​including: Based on the target resistance value, all reference resistors with resistance values ​​less than a preset threshold are selected from the real value database of the resistor array, and the reference resistors are sorted in descending order of resistance value. Starting with the reference resistor with the largest resistance, resistors are selected and stacked sequentially until the deviation between the combined resistance and the target resistance is less than the preset value, thus generating the initial resistance combination. Calculate the deviation rate of each resistor in the initial resistor combination. If the total deviation rate of the initial resistor combination is greater than the target accuracy requirement, remove the resistor with the largest deviation rate in the current combination and replace it with a resistor with a smaller resistance value. Repeat the deviation optimization process until the total resistance deviation rate meets the target accuracy requirement, then stop and generate a corrected resistor combination. Based on the real-time temperature data collected by the temperature sensor, the temperature-resistance drift curve database is called to correct the temperature drift of each resistor in the correction resistor combination, and the corrected combined resistance value is obtained.

[0017] Preferably, the formula for calculating the deviation rate of each resistor in the initial resistor combination is: ; In the formula, This represents the deviation rate of the resistors in the initial resistor combination. Indicates reference resistance The nominal value, Indicates reference resistance The actual resistance value, Indicates the resistor serial number.

[0018] The beneficial effects of this invention are as follows: 1. This invention eliminates the need to purchase a large number of ultra-high precision single high-resistance resistors. It only requires a small number of small to medium-resistance resistors with relatively low precision requirements (e.g., 0.5% or even 1%). High precision requirements can be achieved through screening and combination. The cost of the high-voltage relay is much lower than that of multiple ultra-high precision high-resistance resistors, thereby reducing the overall cost of the device.

[0019] 2. This invention calibrates and stores the true values ​​of each basic resistor, relay contact resistance, and lead resistance on a one-to-one basis. The true values ​​are used for calculation and combination during synthesis. Through optimized pairing of algorithms, positive and negative deviations can be canceled out. Through secondary compensation by temperature drift compensation and accuracy compensation modules, accuracy and stability are further improved. The final accuracy depends on the accuracy of the calibration equipment, the repeatability of the relay, and the accuracy of temperature compensation, rather than the initial accuracy of the resistor itself, thus breaking through the accuracy limitation of a single resistor.

[0020] 3. The resistor array in this invention can be programmed to generate standard resistors covering any resistance value within its design range. All reference resistors are fully utilized, eliminating the need to prepare independent resistors for each fixed range, which greatly improves resource utilization. Users can flexibly set the target resistance value through the external interface module to meet the needs of different metering scenarios.

[0021] 4. The programmable standard resistor device provided by this invention can replace the corresponding component and recalibrate the local component if a reference resistor or relay is damaged, without scrapping the entire high-resistance standard module, thus reducing maintenance costs. By upgrading the algorithm of the control module, the accuracy and function of the device can be further improved, and the service life of the device can be extended.

[0022] 5. The switch switching module in this invention adopts opto-isolation technology to avoid electromagnetic interference to the control module when the relay is activated; the reference resistor adopts a low temperature coefficient resistor and has undergone high temperature aging treatment to ensure long-term stability; the device shell adopts a metal shielding design, which can effectively resist external electromagnetic interference.

[0023] 6. This invention utilizes multiple relatively low-cost, medium-to-high precision small-to-medium resistance resistors as basic units. Through precise switching of high-voltage relays, these basic units are flexibly connected in series to synthesize the required high-resistance standard resistor. A pre-screening and pairing strategy is used to cancel out the deviations between multiple resistors. Then, a precision compensation module composed of low-resistance resistors performs secondary compensation. At the same time, a compensation and calibration mechanism for relay contact resistance and lead resistance is introduced, so that the total resistance after synthesis reaches a level far higher than the original precision of a single resistor. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a circuit principle structure block diagram of a programmable resistor device based on resistor series and dynamic combination according to an embodiment of the present invention. Figure 2 This is a functional flowchart of the control and calculation module in the control method of a programmable resistor device based on resistor series and dynamic combination according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the gate structure of the resistor array module in a programmable resistor device based on resistor series and dynamic combination according to an embodiment of the present invention. Figure 4 This is a flowchart illustrating the precision compensation module in the control method of a programmable resistor device based on resistor series connection and dynamic combination according to an embodiment of the present invention. Figure 5 This is a schematic diagram of a programmable resistor device based on resistor series connection and dynamic combination according to an embodiment of the present invention.

[0026] In the picture: 1. Resistor array module; 2. Precision compensation module; 3. Switching module; 4. Control and calculation module; 5. External interface module. Detailed Implementation

[0027] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention.

[0028] According to embodiments of the present invention, a programmable resistor device and control method based on resistor series connection and dynamic combination are provided.

[0029] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 5 As shown, the programmable resistor device based on resistor series and dynamic combination according to an embodiment of the present invention includes: a resistor array module 1, a precision compensation module 2, a switch switching module 3, a control and calculation module 4, and an external interface module 5. Among them, the resistor array module 1 has several gears connected in series with the nominal values ​​of the gears in a preset ratio relationship, and each gear is composed of several reference resistors connected in series. The output terminal of resistor array module 1 is connected in series with the input terminal of precision compensation module 2. Precision compensation module 2 is composed of several compensation resistors with binary resistance values ​​connected in series. The switch switching module 3 includes several high-voltage relays. Each resistor in the resistor array module 1 and the accuracy compensation module 2 is connected in parallel with a high-voltage relay. At the same time, each resistor is integrated with a temperature sensor to further ensure the thermal stability of the resistor through temperature compensation. The signal output terminal of the control and calculation module 4 is electrically connected to the control terminal of the switch switching module 3. The control and calculation module 4 uses a microcontroller as the core processor and has a built-in AD acquisition module and temperature compensation module to realize the functions of resistance pairing and synthesis, precision compensation control, relay drive and control, and output value calibration and display. At the same time, the control and calculation module 4 is electrically connected to the temperature sensor built into the resistor array module 1 and the precision compensation module 2 to collect temperature data and perform temperature drift compensation. The resistor array module 1 provides a basic resistance value through a combination of multi-position reference resistors. The accuracy compensation module 2 corrects the deviation with binary distributed compensation resistors. The switch switching module 3 dynamically selects the corresponding reference resistor and compensation resistor through a high-voltage relay and connects them in series to the circuit to output a standard resistance value that meets the requirements.

[0030] In one embodiment, the resistor array module 1 is composed of several ranges, with the nominal value of each range being connected in series at a ratio of 10. Each gear position consists of 9 or 10 reference resistors of the nominal value of that gear position connected in series. The lowest gear position has 10 reference resistors, and the other gear positions have 9 reference resistors.

[0031] In one embodiment, all reference resistors are metal film resistors or alloy resistors, and each reference resistor is integrated with a temperature sensor for real-time acquisition of resistance temperature data.

[0032] In one embodiment, the resistor array module 1 has at least one of the following settings: 0.1MΩ, 1MΩ, 10MΩ, 100MΩ, and 1000MΩ.

[0033] In one embodiment, the accuracy of the compensation resistor in the accuracy compensation module 2 is 1% or 2%, and the resistance value of the compensation resistor is less than the combined resistance value of the resistor array module 1, including at least one of 100Ω, 200Ω, 400Ω, 800Ω, 1kΩ, 2kΩ, 4kΩ, 8kΩ, 10kΩ, and 20kΩ.

[0034] In one embodiment, the high-voltage relay is a magnetically latched high-voltage relay with a contact resistance ≤10mΩ and a withstand voltage ≥2kV.

[0035] In one embodiment, the external interface module 5 communicates bidirectionally with the control and computing module 4. The external interface module 5 includes an RS485 interface, an Ethernet interface, and a touch screen interface. The external interface module 5 has an RS485 interface and an Ethernet interface for communicating with the host computer, receiving the user's target resistance setting command and providing status information; the touch screen interface is used for local operation, supporting target resistance setting, device status viewing and calibration record query.

[0036] According to another embodiment of the present invention, a control method for a programmable resistor device based on resistor series connection and dynamic combination is also provided, the method comprising: The actual resistance value of each reference resistor, the contact resistance and lead resistance of each high-voltage relay are measured and stored using measuring equipment. At the same time, the resistance value change data of the reference resistor at different temperatures are recorded, and a temperature-resistance drift curve database is established based on the resistance value change data. The target resistance value input by the user is received through the external interface module 5; A combined optimization strategy is formed by combining greedy strategy, deviation compensation optimization and temperature drift compensation strategy. The combined optimization strategy is used to select resistor combinations from the real value database of resistor array to obtain the corrected composite resistance value. The deviation between the corrected combined resistance and the target resistance is calculated. Based on the magnitude and direction of the deviation, a compensation resistor with the corresponding resistance value is selected from the accuracy compensation module 2 and connected to the circuit. At the same time, the influence of the high-voltage relay contact resistance and lead resistance is deducted during the compensation process. Based on the resistor combination and compensation scheme, a drive signal is generated to control the corresponding high-voltage relay group to operate. The selected reference resistor and compensation resistor are connected in series to the circuit, and the unselected resistor is short-circuited by the high-voltage relay connected in parallel with it. The composite value is calculated based on the actual resistance value of the stored reference resistor, the corrected composite resistance value, the compensation resistor value, and the corrected values ​​of the relay and lead resistance. The composite value is then used as the standard output value and displayed through the external interface module 5.

[0037] In one embodiment, a combined optimization strategy is formed by combining a greedy strategy, a deviation compensation optimization strategy, and a temperature drift compensation strategy. This combined optimization strategy is used to select resistor combinations from the true value database of the resistor array, resulting in corrected composite resistance values, including: Based on the target resistance value, all reference resistors with resistance values ​​less than a preset threshold are selected from the real value database of the resistor array, and the reference resistors are sorted in descending order of resistance value. Starting with the reference resistor with the largest resistance, resistors are selected and stacked sequentially until the deviation between the combined resistance and the target resistance is less than the preset value, thus generating the initial resistance combination. Calculate the deviation rate of each resistor in the initial resistor combination. If the total deviation rate of the initial resistor combination is greater than the target accuracy requirement, remove the resistor with the largest deviation rate in the current combination and replace it with a resistor with a smaller resistance value. Repeat the deviation optimization process until the total resistance deviation rate meets the target accuracy requirement, then stop and generate a corrected resistor combination. Based on the real-time temperature data collected by the temperature sensor, the temperature-resistance drift curve database is called to correct the temperature drift of each resistor in the correction resistor combination, and the corrected combined resistance value is obtained.

[0038] This invention achieves wide-range, high-precision, and low-cost programmable standard resistor output through technologies such as resistor series connection and dynamic combination, deviation complementary pairing, accuracy compensation, and temperature drift compensation. It is suitable for various high-accuracy measurement scenarios and has significant economic and practical value.

[0039] To facilitate understanding of the above technical solutions of the present invention, the following further explains the above technical solutions of the present invention from the perspective of architecture and principle, as follows: The programmable resistor device based on resistor series and dynamic combination provided by the present invention includes a resistor array module 1, a precision compensation module 2, a switch switching module 3, a control and calculation module 4, and an external interface module 5.

[0040] The output terminal of the resistor array module 1 is connected in series with the input terminal of the precision compensation module 2. The switch switching module 3 is connected in parallel with each resistor of the resistor array module 1 and the precision compensation module 2. The signal output terminal of the control and calculation module 4 is electrically connected to the control terminal of the switch switching module 3. The external interface module 5 communicates bidirectionally with the control and calculation module 4. The control and calculation module 4 is also electrically connected to the temperature sensors built into the resistor array module 1 and the precision compensation module 2 to collect temperature data and perform temperature drift compensation.

[0041] like Figure 3 As shown ( Figure 3 In this diagram, A represents the reference resistor and B represents the high-voltage relay. Resistor array module 1 consists of N ranges connected in series, such as 0.1MΩ, 1MΩ, 10MΩ, 100MΩ, etc.; each range consists of 9 or 10 (10 only for the lowest range) reference resistors with the nominal value of that range. , … or The resistors are connected in series. The rated accuracy of each reference resistor can be relaxed to 0.5% or 1%, instead of the final requirement of 0.2% or 0.1%. All reference resistors are low temperature coefficient metal film resistors or alloy resistors, and each reference resistor undergoes high-temperature aging treatment to ensure long-term stability. Each reference resistor is equipped with a miniature temperature sensor for real-time acquisition of resistance temperature data.

[0042] The precision compensation module 2 consists of several low-resistance precision resistors, such as 100Ω, 200Ω, 400Ω, 800Ω, 1kΩ, 2kΩ, 4kΩ, 8kΩ, 10kΩ, etc., connected in series, with their resistance values ​​distributed in a binary pattern. Each resistor requires a precision of 1% or 2%. Because its resistance value is much smaller than the combined resistance of the resistor array module 1, the error caused by its precision is extremely low in the total resistance (for example, when combining a 200MΩ resistor, the compensation resistor is 2kΩ; a 1% error in 2kΩ is only 20Ω, which has no significant impact on the 0.1% precision of 200MΩ). The input terminal of the precision compensation module 2 is connected in series with the output terminal of the resistor array module 1, and the output terminal serves as the overall output terminal of the entire device. Each resistor within the module is connected in parallel with a relay to control its connection or short circuit. When the deviation between the resistance value synthesized by the resistor array module 1 and the target resistance value exceeds the threshold, the control and calculation module 4 drives the relay of the compensation module to switch according to the direction and magnitude of the deviation, and connects the compensation resistor with the corresponding resistance value to realize the fine adjustment of the synthesized total resistance value, and further improve the accuracy to the target range.

[0043] The switch module 3 consists of (M+K) high-voltage relays, where M is the total number of reference resistors in the resistor array module 1, and K is the total number of resistors in the accuracy compensation module 2. All relays are low-contact-resistance, high-voltage magnetically latched high-voltage relays, with a contact resistance ≤10mΩ and a withstand voltage ≥2kV, meeting the insulation requirements of high-resistance composite scenarios. Each reference resistor... A relay is connected in parallel across the two ends of (i=1 to M). A relay is connected in parallel across each compensation resistor. (j=1 to K). All relays are controlled by the control and calculation module 4. By controlling the on / off state of the relays, specified reference resistors and compensation resistors can be connected or short-circuited, thereby dynamically changing the effective resistance value from the input to the output. For example, when it is necessary to connect... and At that time, control and When the circuit is open, the remaining parallel relays close; when a short circuit is required... At that time, control Simply close it.

[0044] Control and calculation module 4 uses a high-performance microcontroller (MCU) as its core processor and integrates a high-precision AD acquisition module and a temperature compensation algorithm module, including: like Figure 2 As shown ( Figure 2 In this context, Rx represents the equivalent precision standard resistance of the system's external representation. Calibration and storage: During factory or periodic calibration, use an external, higher-precision measuring device, such as an 8.5-digit digital multimeter, to measure each reference resistor. Actual resistance Contact resistance of each relay and lead resistance Accurate measurements are taken and stored; simultaneously, resistance changes of the reference resistor at different temperatures (e.g., -10℃ to 60℃) are recorded to establish a temperature-resistance drift curve database. The storage unit uses non-volatile memory (e.g., Flash) to ensure that data is not lost after power failure.

[0045] Resistor pairing and synthesis: When a user requests a target resistance value R through external interface module 5 目标 When the resistance is 250MΩ (e.g., 250MΩ), the control module runs an algorithm to intelligently select a resistor combination from the stored actual values ​​of the reference resistors, so that the combined resistance R... 合成 Closest to R 目标 Furthermore, the deviations cancel each other out. The algorithm employs a combination of greedy strategy, deviation compensation optimization, and temperature drift compensation. The specific steps are as follows: Step 1: Based on the target resistance value R input by the user. 目标From the database of real values ​​of the resistor array, filter out all resistors with resistance values ​​less than R. 目标 The reference resistors are sorted by resistance value from largest to smallest; Step 2: Use a greedy strategy for initial combination: Start with the resistor with the largest resistance value, and successively select and add resistors until the combined resistance value R is reached. 合成 With R 目标 The deviation is less than a preset threshold, such as 0.1%; Step 3, Deviation Compensation Optimization, includes calculating the deviation rate of each resistor in the initial combination: ; In the formula, This represents the deviation rate of the resistors in the initial resistor combination. Indicates reference resistance The nominal value, Indicates reference resistance The actual resistance value, Indicates the resistor serial number; if the total deviation rate of the combination If the deviation rate exceeds the target accuracy requirement, remove the resistor with the largest deviation rate from the combination and replace it with 1 to 2 resistors with smaller resistance values. Prioritize resistors with opposite deviation signs (e.g., replace positive deviation resistors with negative deviation resistors) until the total deviation rate meets the requirement.

[0046] Among them, the total deviation rate The calculation formula is: ; In the formula, The total deviation rate, r The required output resistance value. The reference resistor is the sum of the nominal values ​​of all selected resistors. For example, to obtain an output resistance of 250MΩ, the selected reference resistor might be: r 3+ r 4+ r 10+ r 11+ r 12+ r 13+ r 14+ r 15.

[0047] Since all the reference resistors used are resistors with a detection accuracy of 1%, the above resistor combination: r 3+ r 4+ r 10+ r 11+ r 12+ r 13+ r 14+ rThe actual resistance of resistor 15 should fall within the range of 250MΩ ± 1% (250 ± 2.5) MΩ. If the measured actual resistance is negative, such as 248MΩ (-0.8%), and the desired actual output value is within the range of 250MΩ ± 0.1%, that is, (250 ± 0.25) MΩ, the programmable resistor device of this invention can directly add one or two 1MΩ resistors to form a satisfactory output combination resistor. If the measured resistance is positive, such as 252MΩ (0.8%), a minimum value resistor (e.g., r15, assuming its nominal value is 10.9MΩ) will be removed and replaced with the next lower value resistor (requiring 8 to 9 resistors) to obtain the most ideal output resistance.

[0048] Step 4, Temperature Drift Compensation, includes: based on real-time temperature data collected by the temperature sensor, calling the temperature-resistance drift curve database, correcting the temperature drift of each resistor in the combination, and obtaining the corrected combined resistance value R. 合成 '.

[0049] like Figure 4 As shown, the accuracy compensation control includes: addressing the issue of high error weighting of the reference resistor in the high resistance range of resistor array module 1, the control and calculation module 4 first calculates and corrects the then synthesized resistance value R. 合成 'and target resistance R 目标 The deviation ΔR=R 合成 '-R 目标 Then, based on the magnitude and direction of ΔR, a compensation resistor with the corresponding resistance value is selected from the precision compensation module 2 and connected to the circuit to achieve fine adjustment of the total resistance value; at the same time, the influence of relay contact resistance and lead resistance needs to be deducted during the compensation process to ensure compensation accuracy.

[0050] The circuit schematic is as follows: Figure 1As shown, Vout is the standard voltage; GND_A is the signal ground; +15V and -15V provide positive and negative power supplies; Rout is the resistance signal output to the main controller, which then adjusts K1-K5 to obtain the most accurate output resistance value based on the tested resistance value; R1-8 and R14 are 10kΩ standard resistors; R9-R13 are 5kΩ compensation selection resistors; K1-K5 are relays used to select R9-R13; N1 is an operational amplifier that increases the input impedance and decreases the output impedance, preparing for subsequent high-precision amplification; N 2 is the op-amp for signal amplification; based on the resistance values ​​of R17 and R18, the signal amplification can be calculated to be 4 times. C1-C4 are the op-amp power supply bypass capacitors, which filter, reduce interference signals, and stabilize the power supply. R15 and R9 are resistor voltage dividers to select the signal voltage. RP1 is a 5K potentiometer, which, together with R9, finely selects the appropriate voltage. CBB103 is a filter capacitor, which further stabilizes the signal through filtering. R17, R18, and op-amp N2 form the op-amp amplification circuit; based on the resistance values ​​in the diagram, the signal can be amplified by 4 times. R16 is the input isolation resistor for op-amp N2.

[0051] Specifically, the standard voltage Vout is applied to the resistor terminals R1-R14, and resistors R13-R9 are used as adjustment resistors; op-amps N2 and N3 form a signal amplification, adjustment, and feedback circuit that can output a high-precision signal. Based on the output signal RI, the MCU selects two resistors from resistors R9-R13 to form a 10k resistor, which together with the other nine resistors forms a standard high-precision resistor conforming to 100k.

[0052] It should be noted that R1-R14 simulate a specific output resistor (based on the test resistor values, R1-R8 and R14 are standard resistors of 100MΩ to 10kΩ; R9-R13 are compensation selection resistors of 100Ω to 5kΩ; K1-K5 are relays used to select R9 to R13). The voltage follower, filter, amplifier, etc. in the circuit measure voltage signals to determine whether the actual output resistance value is correct (e.g., in case of damage to the selected resistor or high-voltage relay). This circuit feeds back to the main control module, which adjusts the corresponding output resistance and outputs the location and name of the damaged component for easy repair.

[0053] The relay drive and control functions include: generating drive signals based on the selected resistor combination and compensation scheme, controlling the corresponding relay group to operate, connecting the selected reference resistor and compensation resistor in series to the circuit, and short-circuiting the unselected resistors by the relays connected in parallel with them; the drive module adopts opto-isolation technology to avoid electromagnetic interference to the control module when the relay operates.

[0054] The output value calibration and display function includes: the nominal value of the device's final output is based on the stored actual measurement value. The combined value R, calculated from the temperature drift correction value, the compensation resistor value, and the relay and lead wire resistance correction values, is used as the "standard value" output by this device. Because... The measurement accuracy is much higher than that of the resistor itself (for example, the accuracy of external measuring equipment can reach 0.01%). Therefore, the accuracy of the synthesized value R depends only on this high-precision measurement, the stability of the relay, and the accuracy of temperature compensation, thus easily achieving an overall accuracy of 0.2% or even higher.

[0055] External interface module 5 includes an RS485 interface, an Ethernet interface, and a touch screen interface. The RS485 and Ethernet interfaces are used to communicate with the host computer, receive the user's resistance setting instructions, and feed back the device's current output composite resistance, temperature data, relay status, and other information to the host computer; the touch screen interface is used for local operation, allowing users to directly set the target resistance value, view the device status, and calibration records via the touch screen.

[0056] The essential difference between this invention and traditional combination schemes lies in the following aspects: I. Introduce a pre-calibration and real value storage mechanism, abandon the nominal value of the resistance, and use the real value measured by high-precision equipment (including relay contact resistance and lead resistance) as the basis for synthesis; Second, the unique deviation cancellation matching algorithm is not a simple addition of resistance values, but actively selects resistor combinations with positive and negative deviations, and uses the deviation complementary effect to overcome the accuracy limitations of a single resistor. Third, the low-resistance accuracy compensation module 2 is innovatively used to recompensate the high-resistance scenario of the traditional combination scheme, and a temperature drift compensation mechanism is introduced to further improve the accuracy and stability. Fourth, adopt a magnetic latching high-voltage relay with low contact resistance and high withstand voltage, and measure and compensate its contact resistance during the calibration process to avoid introducing additional errors into the relay.

[0057] The programmable resistor device based on resistor series connection and dynamic combination provided by the present invention will be further described below with reference to Examples 1-2.

[0058] Example 1 This embodiment provides a programmable resistor device based on series and dynamic combination of resistors for the calibration of insulation resistance testers, with a target resistance range of 0.1MΩ to 1000MΩ and an accuracy requirement of 0.1%.

[0059] The resistor array module 1 has five ranges: 0.1MΩ, 1MΩ, 10MΩ, 100MΩ, and 1000MΩ. The 0.1MΩ range consists of ten 0.1MΩ reference resistors connected in series, while the other ranges each consist of nine reference resistors with corresponding nominal values ​​connected in series, for a total of 10 + 9 × 4 = 46 reference resistors. All reference resistors are metal film resistors with an accuracy of 0.5% and a temperature coefficient ≤10ppm / ℃. Each reference resistor integrates a miniature NTC temperature sensor for real-time temperature data acquisition.

[0060] The precision compensation module 2 consists of 10 low-resistance precision resistors connected in series, with resistance values ​​of 100Ω, 200Ω, 400Ω, 800Ω, 1kΩ, 2kΩ, 4kΩ, 8kΩ, 10kΩ, and 20kΩ, arranged in a binary configuration, with a precision of 1%. Each resistor is connected in parallel with a magnetically latched high-voltage relay, with a contact resistance ≤10mΩ and a withstand voltage ≥2kV.

[0061] The switch module 3 consists of 46 + 10 = 56 magnetically latched high-voltage relays, with one relay connected in parallel for each reference resistor and compensation resistor. The relay drive module uses opto-isolation technology to avoid electromagnetic interference.

[0062] The control and calculation module 4 uses an STM32H743 microcontroller as its core processor, with a built-in 16-bit high-precision AD acquisition module and Flash memory. During calibration, an 8.5-bit digital multimeter is used to measure the actual resistance of each reference resistor, the relay contact resistance, and the lead resistance, with a measurement accuracy of 0.01%. Resistance changes at different temperatures are recorded, establishing a temperature-resistance drift curve database. The resistor pairing and synthesis algorithm employs a combination of greedy strategy, deviation compensation optimization, and temperature drift compensation to ensure the accuracy and stability of the synthesized resistance values.

[0063] External interface module 5 design: External interface module 5 includes an RS485 interface, an Ethernet interface, and a 7-inch touchscreen interface. Users can directly set the target resistance value, view the device status, and calibration records via the touchscreen; they can also communicate with a host computer via the RS485 or Ethernet interface to achieve remote control and data acquisition.

[0064] The working process includes: When the user needs to calibrate the 250MΩ range of the insulation resistance tester, they input the target resistance value of 250MΩ via the touchscreen. The control and calculation module 4 first filters all reference resistors with resistance values ​​less than 250MΩ from the real-value database of the resistor array, sorting them from largest to smallest resistance value. Then, a greedy algorithm is used for initial combination, selecting two 100MΩ and five 10MΩ reference resistors, resulting in a combined resistance value of 2×100MΩ + 5×10MΩ = 250MΩ. Next, the deviation rate of each resistor in the combination is calculated, and deviation optimization ensures the total deviation rate is ≤0.05%. Then, based on real-time temperature data collected by the temperature sensor, temperature drift correction is applied to the resistance value of each resistor in the combination. Finally, the deviation between the corrected combined resistance value and the target resistance value is calculated. If the deviation exceeds a threshold, the relay of the accuracy compensation module 2 is switched, connecting the corresponding compensation resistor to achieve fine adjustment of the total resistance value. The final output standard value of the device is a composite value after temperature drift compensation, accuracy compensation, and relay and lead resistance compensation, with an accuracy of up to 0.1%.

[0065] To verify the accuracy, stability and reliability of the device in Example 1, a full-range performance test was conducted in accordance with the "JJG622-2017 DC Resistor Verification Procedure". The test environment was a temperature of 23℃±1℃ and a relative humidity of 45%±5%. The test equipment was an 8.5-digit digital multimeter (accuracy 0.01%).

[0066] 1. Accuracy test: Five typical resistance values ​​of 0.1MΩ, 10MΩ, 250MΩ, 500MΩ, and 1000MΩ were selected for testing. Each resistance value was measured 10 times. The test results are shown in Table 1.

[0067] Table 1 Accuracy Test Results The accuracy test results are shown in Table 1. The maximum relative error of each typical resistance point is much less than the accuracy requirement of 0.1%, and the accuracy of the device meets the design specifications.

[0068] 2. Temperature stability test: A resistance value of 250MΩ was selected, and tests were conducted at five temperature points: -10℃, 0℃, 23℃, 40℃, and 60℃. After holding the temperature at each point for 2 hours, the measurements were taken. The test results are shown in Table 2.

[0069] Table 2 Temperature stability test results The temperature stability test results are shown in Table 2. The temperature coefficient of the device is less than 10ppm / ℃ in the temperature range of -10℃ to 60℃, and the temperature stability meets the design specifications.

[0070] 3. Long-term reliability testing: A resistance value of 100MΩ was selected, and the device was continuously powered on for 1000 hours. The resistance value was measured every 100 hours. The test results showed that the measured resistance value after 1000 hours was 100.003MΩ, which was 3kΩ away from the initial value. The relative deviation was 0.003%, indicating that the device has good long-term stability.

[0071] 4. Relay switching reliability test: The 56 relays of the switch switching module 3 were subjected to 100,000 on / off cycle tests. After the test, the contact resistance of the relays was measured. The results showed that the contact resistance of all relays was still ≤10mΩ, with no contact sticking or poor contact. The switching reliability met the design requirements.

[0072] Example 2 The difference between this embodiment 2 and embodiment 1 is that the reference resistor is an alloy resistor with an accuracy of 1%, and the resistor of the accuracy compensation module 2 is a carbon film resistor with an accuracy of 2%. By optimizing the resistor pairing and synthesis algorithm, the accuracy requirement of 0.2% can still be achieved, further reducing the equipment cost. In order to verify the performance of the device in this embodiment at a lower cost, the test was carried out in the same test environment and method as in embodiment 1.

[0073] 1. Accuracy test: Five typical resistance values ​​of 0.1MΩ, 10MΩ, 250MΩ, 500MΩ, and 1000MΩ were selected for testing. Each resistance value was measured 10 times. The test results are shown in Table 3.

[0074] Table 3 Accuracy Test Results As shown in Table 3, the maximum relative error at each typical resistance point is less than the accuracy requirement of 0.2%. The device still meets the design specifications even when using lower precision resistors.

[0075] 2. Cost comparison test: The costs of Example 1, Example 2 and the traditional solution (each gear is equipped with an independent high-precision resistor) are compared, and the results are shown in Table 4 (unit: RMB 10,000).

[0076] Table 4 Cost Comparison Test Results As shown in Table 4, the cost reduction ratio of the present invention exceeds 70% compared with the traditional solution, and the cost reduction ratio of Example 2 exceeds 80%, demonstrating a significant cost advantage.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A programmable resistor device based on resistor series connection and dynamic combination, characterized in that, Includes: resistor array module, precision compensation module, switch switching module, control and calculation module, and external interface module; The resistor array module has several gears connected in series with the nominal values ​​of the gears in a preset ratio relationship. Each gear is composed of several reference resistors connected in series. The output terminal of the resistor array module is connected in series with the input terminal of the precision compensation module. The precision compensation module is composed of several compensation resistors with binary resistance values ​​connected in series. The switching module includes several high-voltage relays. Each resistor in the resistor array module and the precision compensation module is connected in parallel with a high-voltage relay. At the same time, each resistor is integrated with a temperature sensor to further ensure the thermal stability of the resistor through temperature compensation. The signal output terminal of the control and calculation module is electrically connected to the control terminal of the switch switching module. The control and calculation module is used to collect and store measurement data including the actual resistance value of the reference resistor, the contact resistance of the high voltage relay, and the lead resistance data. Based on the measurement data, it performs resistor pairing and synthesis, accuracy compensation control, and output value calibration respectively. At the same time, it combines greedy strategy, deviation compensation optimization, and temperature drift compensation strategy to form a combined optimization strategy, select resistor combinations, and correct the synthesized resistance value. The resistor array module provides a basic resistance value through a combination of multi-level reference resistors. The precision compensation module corrects deviations with binary distributed compensation resistors. The switch switching module dynamically selects the corresponding reference resistor and compensation resistor through a high-voltage relay and connects them in series to the circuit to output a standard resistance value that meets the requirements.

2. The programmable resistor device based on resistor series connection and dynamic combination according to claim 1, characterized in that, The resistor array module consists of several levels, with the nominal value of each level connected in series at a ratio of 10. Each gear position consists of 9 or 10 reference resistors of the nominal value of that gear position connected in series. The lowest gear position has 10 reference resistors, and the other gear positions have 9 reference resistors.

3. The programmable resistor device based on resistor series connection and dynamic combination according to claim 2, characterized in that, All reference resistors are metal film resistors or alloy resistors, and each reference resistor is equipped with a temperature sensor for real-time acquisition of resistance temperature data.

4. The programmable resistor device based on resistor series connection and dynamic combination according to claim 3, characterized in that, The resistor array module has at least one of the following settings: 0.1MΩ, 1MΩ, 10MΩ, 100MΩ, and 1000MΩ.

5. The programmable resistor device based on resistor series connection and dynamic combination according to claim 1, characterized in that, The accuracy of the compensation resistor in the accuracy compensation module is 1% or 2%, and the resistance value of the compensation resistor is less than the combined resistance value of the resistor array module, including at least one of 100Ω, 200Ω, 400Ω, 800Ω, 1kΩ, 2kΩ, 4kΩ, 8kΩ, 10kΩ, and 20kΩ.

6. The programmable resistor device based on resistor series connection and dynamic combination according to claim 1, characterized in that, The high-voltage relay is a magnetic latching high-voltage relay with a contact resistance ≤10mΩ and a withstand voltage ≥2kV. The control and calculation module is electrically connected to the temperature sensor built into the resistor array module and the accuracy compensation module, and is used to collect temperature data and perform temperature drift compensation.

7. The programmable resistor device based on resistor series connection and dynamic combination according to claim 1, characterized in that, The external interface module communicates bidirectionally with the control and computing module. The external interface module includes an RS485 interface, an Ethernet interface, and a touch screen interface. The RS485 interface and Ethernet interface of the external interface module are used to communicate with the host computer, receive the user's target resistance setting command and provide feedback on status information; the touch screen interface is used to support target resistance setting, device status viewing and calibration record query.

8. A control method for a programmable resistor device based on resistor series connection and dynamic combination, used to implement the control of the programmable resistor device based on resistor series connection and dynamic combination as described in any one of claims 1-7, characterized in that, The method includes: The actual resistance value of each reference resistor, the contact resistance and lead resistance of each high-voltage relay are measured and stored using measuring equipment. At the same time, the resistance value change data of the reference resistor at different temperatures are recorded, and a temperature-resistance drift curve database is established based on the resistance value change data. The target resistance value input by the user is received through an external interface module; A combined optimization strategy is formed by combining greedy strategy, deviation compensation optimization and temperature drift compensation strategy. The combined optimization strategy is used to select resistor combinations from the real value database of resistor array to obtain the corrected composite resistance value. The deviation between the corrected combined resistance and the target resistance is calculated. Based on the magnitude and direction of the deviation, a compensation resistor with the corresponding resistance value is selected from the accuracy compensation module and connected to the circuit. At the same time, the influence of the high-voltage relay contact resistance and lead resistance is deducted during the compensation process. Based on the resistor combination and compensation scheme, a drive signal is generated to control the corresponding high-voltage relay group to operate. The selected reference resistor and compensation resistor are connected in series to the circuit, and the unselected resistor is short-circuited by the high-voltage relay connected in parallel with it. The composite value is calculated based on the actual resistance value of the stored reference resistor, the corrected composite resistance value, the compensation resistor value, and the corrected values ​​of the relay and lead resistance. The composite value is then used as the standard output value and displayed through an external interface module.

9. The control method for a programmable resistor device based on resistor series connection and dynamic combination according to claim 8, characterized in that, The combined greedy strategy, deviation compensation optimization, and temperature drift compensation strategy form a combined optimization strategy. This combined optimization strategy selects resistor combinations from the true value database of the resistor array to obtain the corrected composite resistance value, including: Based on the target resistance value, all reference resistors with resistance values ​​less than a preset threshold are selected from the real value database of the resistor array, and the reference resistors are sorted in descending order of resistance value. Starting with the reference resistor with the largest resistance, resistors are selected and stacked sequentially until the deviation between the combined resistance and the target resistance is less than the preset value, thus generating the initial resistance combination. Calculate the deviation rate of each resistor in the initial resistor combination. If the total deviation rate of the initial resistor combination is greater than the target accuracy requirement, remove the resistor with the largest deviation rate in the current combination and replace it with a resistor with a smaller resistance value. Repeat the deviation optimization process until the total resistance deviation rate meets the target accuracy requirement, then stop and generate a corrected resistor combination. Based on the real-time temperature data collected by the temperature sensor, the temperature-resistance drift curve database is called to correct the temperature drift of each resistor in the correction resistor combination, and the corrected combined resistance value is obtained.

10. The control method for a programmable resistor device based on resistor series connection and dynamic combination according to claim 9, characterized in that, The formula for calculating the deviation rate of each resistor in the initial resistor combination is as follows: ； In the formula, This represents the deviation rate of the resistors in the initial resistor combination. Indicates reference resistance The nominal value, Indicates reference resistance The actual resistance value, Indicates the resistor serial number.

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