CN112649672A - Multi-module parallel electronic load - Google Patents
Multi-module parallel electronic load Download PDFInfo
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- CN112649672A CN112649672A CN202011517479.8A CN202011517479A CN112649672A CN 112649672 A CN112649672 A CN 112649672A CN 202011517479 A CN202011517479 A CN 202011517479A CN 112649672 A CN112649672 A CN 112649672A
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- 238000005070 sampling Methods 0.000 claims abstract description 32
- 230000000694 effects Effects 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 230000001276 controlling effect Effects 0.000 description 5
- 238000013461 design Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
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- 239000003990 capacitor Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
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- 230000020169 heat generation Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
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- 238000012827 research and development Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
Abstract
The invention discloses a multi-module parallel electronic load which comprises a plurality of parallel modules, wherein the parallel modules are all connected with a summing circuit, and each module is internally provided with a sampling resistor, a differential sampling circuit and a proportional operational amplifier circuit. The sampling resistor is a current equalizing resistor with good temperature coefficient and high precision; the differential sampling circuit is internally provided with a high-speed differential operational amplifier; the proportional operational amplifier circuit is provided with an adjustable potentiometer. The current sharing of a single power adjusting tube and a plurality of modules is realized through a simple circuit, the current sharing effect is good, the circuit is simple, the cost is low, the module current sharing problem is solved, the production efficiency is improved, the consistency of the current sharing degree of the modules is ensured in the parallel connection use of the modules, and the reliability of an electronic load is improved.
Description
Technical Field
The present disclosure relates to electronic loads, and particularly to a multi-module parallel electronic load.
Background
The electronic load is a device which consumes electric energy by controlling the dissipation power of an internal power device, and is mainly suitable for various power supplies, batteries, adapters and occasions needing electronic load tests. The test device can provide a strong test environment to meet different test requirements, and is a vital device in power supply research and development and production. The electronic loads on the market are various in types, and corresponding work can be completed more efficiently and with higher quality by selecting proper electronic loads.
The electronic load can realize the constancy of the output loop current of the power device by controlling the conduction quantity (duty ratio size) of an internal power (MOSFET) or a transistor. The current flowing through a single power device is limited, and the excessive current can cause excessive dissipation power and easily burn out the power device. Therefore, in engineering applications, the electronic load is usually designed in a manner of multiple parallel pipes. When the power tubes are used in parallel, the current flowing through each device needs to be controlled to be consistent. If the working current of each power tube is unevenly distributed for a long time, the service life may be inconsistent and even damaged. At present, there are many measures for improving the current sharing, such as selecting elements, improving a driving circuit, adding a balancing reactor and the like.
With the development of the power industry in the direction of large current and large capacity, an electronic load with high power density is required in the testing process. While the parallel connection of multiple power devices cannot meet the power requirement, the electronic load is developed towards the direction of parallel connection of multiple modules or branches. Therefore, the expansion of any capacity can be conveniently realized, and the requirements of various high powers are met. Meanwhile, the parallel operation is an effective means for realizing the system redundancy design, and the reliability of the system operation can be improved. The parallel connection mode of a plurality of power devices is the same, and the current sharing is also an important problem to be solved in the process of parallel connection of a plurality of modules. Uneven current distribution can cause inconsistency of modules, overload can occur, power is damaged, or a local hot spot or a local over-force spot occurs on a certain branch, so that elements are deformed or damaged, and reliability of the system is reduced. On the contrary, if the current equalizing effect of the parallel modules is good, the utilization rate of each module or each branch circuit element is equivalent, the margin is proper, and the reliability of the electronic load is effectively guaranteed.
However, the conventional method for improving the multi-tube parallel current sharing problem is no longer applicable to the multi-module electronic load design.
The first prior art is as follows:
as shown in fig. 1, in order to solve the problem of multi-tube parallel current sharing, a feedback circuit is usually added to the circuit design of the electronic load. As shown in the following figure, the MOS tube and the resistor Rs form a negative feedback circuit, the MOS tube works in a constant current region, the non-inverting end of the operational amplifier regulates and sets a constant current value, and the current of the MOS tube generates a voltage drop on the resistor Rs and is fed back to the inverting end of the operational amplifier to realize the control of output current.
U1 Is the reference voltage and sends into the operational amplifier homophase end, and after the current Is of MOS pipe output loop was converted into voltage through Rs, the feedback realized control Vgs to the operational amplifier inverting terminal to control MOS pipe output loop current Is's stability. The capacitor C1 is used for eliminating noise waves and compensating trapezoidal waves output by the operational amplifier, the similar voltage change speed is reduced, and oscillation possibly caused by high-frequency change of the G-voltage of the MOS tube is avoided as much as possible.
The first prior art has the following defects:
when a plurality of power regulating tubes are connected in parallel to use the scheme, the DRIVE of each operational amplifier unit is a driving signal, and after the current signals of the power regulating tubes are sampled through Rs1 and Rs2, the current signals are compared with the driving signals in an error mode to control the current flowing through Q1 and Q2. The scheme can accurately realize the current sharing of a plurality of power adjusting tubes theoretically, wherein Rs1 and Rs2 are current sharing resistors with good temperature coefficients and precision, and the consistency of sampling current is guaranteed. In the application process of the scheme, however, it needs to be noted that when the current equalizing resistor is selected to be too large, although the current can be accurately sampled, as the current increases, the current equalizing resistor changes in resistance due to power consumption and heat generation, and the sampling voltage is inaccurate, so that the current equalizing effect of the power adjusting tube is different; if the selected current-sharing resistor has a small resistance value, current sharing among the power adjusting tubes can be better realized during large current, and when the power supply works at small current, because the sampled signal is small, if the sampled signal is not processed properly, the current-sharing effect among the power adjusting tubes is inconsistent, and the service life of the power tubes is further influenced. When the number of the power adjusting tubes is increased to expand the power of the electronic load according to the scheme, the more the number of the tubes is, the larger the difference of the current flowing through each power adjusting tube is, so that the current of the power adjusting tubes is not uniform, and the reliability of the electronic load is influenced.
The second prior art is:
as shown in fig. 2, as the power demanded by the electronic load increases, a modular design scheme appears. On the basis of the first prior art, a plurality of power adjusting tubes are connected in parallel and flow equalized to form a single module, each module performs differential sampling on current, and the current of a plurality of modules is subjected to summation control. The scheme adopts a multi-module parallel connection mode to expand power.
The second prior art has the following defects:
the problem in the first technology exists in the aspect of single-module power adjusting tube current sharing, but the number of modules for the whole power adjusting tube is reduced, and the current sharing of the power adjusting tube is improved; in practical application, the sampling resistance of the modules has conditions such as difference, and the difference between the modules can be generated, so that the modules do not have uniform current, and the non-uniform current between the power adjusting tubes is projected.
Disclosure of Invention
The invention aims to provide a multi-module parallel electronic load which solves the problem of module current sharing and improves the production efficiency.
The purpose of the invention is realized by the following technical scheme:
the multi-module parallel electronic load comprises a plurality of parallel modules, wherein the parallel modules are all connected with a summing circuit, and each module is provided with a sampling resistor, a differential sampling circuit and a proportional operational amplifier circuit.
According to the technical scheme provided by the invention, the multi-module parallel electronic load provided by the embodiment of the invention improves the current sharing effect of a single power adjusting tube, ensures the consistency of current sharing degrees of the multiple modules in the parallel use of the multiple modules, and increases the reliability of the electronic load.
Drawings
FIG. 1 is a circuit diagram of a multi-tube parallel current sharing design of the prior art I;
fig. 2 is a schematic diagram of a multi-module parallel electronic load structure of the second prior art;
fig. 3 is a schematic diagram of a multi-module parallel electronic load structure according to an embodiment of the present invention.
Detailed Description
The embodiments of the present invention will be described in further detail below. Details which are not described in detail in the embodiments of the invention belong to the prior art which is known to the person skilled in the art.
The preferred embodiment of the multi-module parallel electronic load of the present invention is as follows:
the circuit comprises a plurality of parallel modules, wherein the parallel modules are connected with a summing circuit, and each module is provided with a sampling resistor, a differential sampling circuit and a proportional operational amplifier circuit.
The sampling resistor adopts a current sharing resistor Rs 1-Rsn with good temperature coefficient and high precision;
the differential sampling circuit is internally provided with a high-speed differential operational amplifier;
the proportional operational amplifier circuit is provided with adjustable potentiometers RV 1-RVn.
The signal sampled by the sampling resistor is amplified through a differential operational amplifier and then is subjected to error comparison with a control signal, so that the consistency of sampling current is ensured;
the high-speed differential operational amplifier in the differential sampling circuit counteracts the introduction of a reference ground current common-mode voltage error caused by inconsistent loop resistance so as to obtain sampling error voltage which is consistent as much as possible;
the control signals are uniformly given for controlling the main operational amplifier, so that the same reference signals are ensured, the single power adjusting tube is automatically equalized through the integral error amplifier, and the equalizing effect of a plurality of power adjusting tubes is ensured in an ideal range.
When a plurality of modules are controlled by the same control signal, the voltage value of the current sharing resistor Rs 1-Rsn in each module is monitored by using a high-precision digital multimeter by adjusting the adjustable potentiometers RV 1-RVn, so that the voltage value of the current sharing resistor Rs 1-Rsn is ensured within a certain error range, and the current sharing error between each module is ensured within a certain range.
The multi-module parallel electronic load improves the current sharing effect of a single power adjusting tube, ensures the consistency of the current sharing degree of the multi-module when the multi-module parallel electronic load is used, and increases the reliability of the electronic load.
The specific embodiment is as follows:
as shown in fig. 2, a differential sampling circuit of the functional block 1 in the figure is added to this scheme. The sampling resistor is a current equalizing resistor with good temperature coefficient and precision, the selected current equalizing resistor is not too large for stable sampling, and a sampled signal is amplified through a differential operational amplifier and then subjected to error comparison with a control signal, so that the consistency of sampling current is ensured. The operational amplifier in the functional module 1 adopts a high-speed differential operational amplifier to counteract the introduction of a reference ground current common-mode voltage error caused by inconsistent loop resistance so as to obtain sampling error voltage which is consistent as much as possible. The control signals are uniformly given for controlling the main operational amplifier, and the same reference signals are ensured. The single power adjusting tube is automatically equalized by the integral error amplifier, and the equalizing effect of a plurality of power adjusting tubes is ensured in an ideal range.
In the scheme, a proportional operational amplifier circuit of a functional module 2 in the figure is added, in order to ensure that a plurality of modules are uniform in current, an adjustable potentiometer RV 1-RVn is added into the functional module 2, and when the same control signal controls the plurality of modules, a high-precision digital multimeter is used for monitoring the voltage values of Rs 1-Rsn by adjusting RV 1-RVn, so that the voltage values of Rs 1-Rsn are ensured within a certain error range. Therefore, the current sharing error among all the modules is guaranteed to be within a certain range.
The multi-module parallel electronic load realizes the current sharing of a single power adjusting tube and a plurality of modules through a simple circuit, has good current sharing effect, simple circuit and low cost, solves the problem of module current sharing, and improves the production efficiency.
The differential sampling circuit is mainly applied to eliminate common-mode signals and common-mode signals introduced by wiring, the difference among components is compensated by the characteristics of the adjustable potentiometer, and the current sharing error among a plurality of power adjusting tubes and a plurality of power modules is improved. The technical key point is that the resistance value adjustable characteristic of the adjustable potentiometer is utilized, the sampled current has the characteristic of changing and controlling, and the problem of parallel current sharing of multiple modules of the electronic load is solved.
In specific implementation, the application device is not a specific type, and the device with related functions can realize related functions when being built according to a circuit.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (4)
1. The utility model provides a parallelly connected electronic load of multimode, includes a plurality of parallel modules, and a plurality of parallel modules all are connected with summation circuit, its characterized in that all is equipped with sampling resistor, difference sampling circuit and proportion operational amplifier circuit in every module.
2. The multi-module parallel electronic load of claim 1, wherein:
the sampling resistor adopts a current sharing resistor (Rs 1-Rsn) with good temperature coefficient and high precision;
the differential sampling circuit is internally provided with a high-speed differential operational amplifier;
the proportional operational amplifier circuit is provided with an adjustable potentiometer (RV 1-RVn).
3. Multi-module parallel electronic load according to claim 1 or 2, characterized in that:
the signal sampled by the sampling resistor is amplified through a differential operational amplifier and then is subjected to error comparison with a control signal, so that the consistency of sampling current is ensured;
the high-speed differential operational amplifier in the differential sampling circuit counteracts the introduction of a reference ground current common-mode voltage error caused by inconsistent loop resistance so as to obtain sampling error voltage which is consistent as much as possible;
the control signals are uniformly given for controlling the main operational amplifier, so that the same reference signals are ensured, the single power adjusting tube is automatically equalized through the integral error amplifier, and the equalizing effect of a plurality of power adjusting tubes is ensured in an ideal range.
4. The multi-module parallel electronic load according to claim 3, wherein when a plurality of modules are controlled by the same control signal, the voltage value of the current sharing resistor (Rs 1-Rsn) in each module is monitored by adjusting the adjustable potentiometer (RV 1-RVn) by using a high-precision digital multimeter, so that the voltage value of the current sharing resistor (Rs 1-Rsn) is ensured within a certain error range, and the current sharing error between each module is ensured within a certain range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011517479.8A CN112649672A (en) | 2020-12-21 | 2020-12-21 | Multi-module parallel electronic load |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011517479.8A CN112649672A (en) | 2020-12-21 | 2020-12-21 | Multi-module parallel electronic load |
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| CN112649672A true CN112649672A (en) | 2021-04-13 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101949962A (en) * | 2010-05-27 | 2011-01-19 | 东莞市锐源仪器有限公司 | Programmable electronic load |
| CN203643587U (en) * | 2013-12-24 | 2014-06-11 | 深圳市智控科技有限公司 | Simple electronic load device |
| CN205304586U (en) * | 2015-12-30 | 2016-06-08 | 四川创宏电气有限公司 | Automatically, circuit flow equalizes based on difference sampling |
| CN108459645A (en) * | 2017-02-22 | 2018-08-28 | 苏州普源精电科技有限公司 | Constant current control loop and electronic load |
| CN108776244A (en) * | 2018-07-25 | 2018-11-09 | 易事特集团股份有限公司 | Electronic load |
| CN109361311A (en) * | 2018-10-25 | 2019-02-19 | 武汉精立电子技术有限公司 | A kind of multi-channel dc power supply current sharing control circuit and method |
-
2020
- 2020-12-21 CN CN202011517479.8A patent/CN112649672A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101949962A (en) * | 2010-05-27 | 2011-01-19 | 东莞市锐源仪器有限公司 | Programmable electronic load |
| CN203643587U (en) * | 2013-12-24 | 2014-06-11 | 深圳市智控科技有限公司 | Simple electronic load device |
| CN205304586U (en) * | 2015-12-30 | 2016-06-08 | 四川创宏电气有限公司 | Automatically, circuit flow equalizes based on difference sampling |
| CN108459645A (en) * | 2017-02-22 | 2018-08-28 | 苏州普源精电科技有限公司 | Constant current control loop and electronic load |
| CN108776244A (en) * | 2018-07-25 | 2018-11-09 | 易事特集团股份有限公司 | Electronic load |
| CN109361311A (en) * | 2018-10-25 | 2019-02-19 | 武汉精立电子技术有限公司 | A kind of multi-channel dc power supply current sharing control circuit and method |
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Application publication date: 20210413 |