Multipath current conversion module for energy storage test

Abstract

The utility model provides a multipath current conversion module for energy storage test, which belongs to the technical field of energy storage test of new energy power stations and comprises a constant current source unit, an input switching circuit, a current-to-voltage circuit, an operational amplifier summing circuit and a reverse-phase amplification circuit. The power supply input end of each path of input switching circuit is connected with an external power supply and a constant current source unit, the output end of each path of input switching circuit is respectively connected with a current-to-voltage circuit, the plurality of paths of current-to-voltage circuits are jointly connected to an operational amplifier summing circuit, and the operational amplifier summing circuit is connected with a reverse amplification circuit. The multi-channel current signal acquisition, conversion and calibration module can support the multi-channel current signal acquisition, conversion and calibration module, so as to improve the efficiency and precision of the energy storage test, reduce the dependence on external equipment, and realize the independent control, accurate measurement and efficient conversion of the multi-channel current.

Description

Technical Field

[0001] This utility model belongs to the field of new energy power station energy storage testing technology, and in particular relates to a multi-channel current conversion module for energy storage testing. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] With the rapid development of new energy power plants (such as energy storage power plants and wind power distribution and storage), energy storage systems are increasingly widely used in power systems. Energy storage systems not only balance power supply and demand but also improve the stability and reliability of the power grid. Energy storage systems typically contain multiple battery packs or energy storage units, each requiring independent current testing and monitoring. During the testing process, multiple current signals need to be acquired and accurately measured in real time. Multi-loop testing usually requires multiple independent testing devices, which not only increases equipment costs but also complicates the testing process.

[0004] Currently, traditional current testing equipment typically only allows testing of a single circuit, failing to meet the need for simultaneous testing of multiple circuits. This results in low testing efficiency and increases testing costs and time. Furthermore, external standard signal sources for calibration usually employ fixed resistors or single-range designs, which are insufficient for multi-range output requirements. The calibration process is also complex and reduces application flexibility. Utility Model Content

[0005] To address the problems of large internal deviations, low efficiency, and complex calibration in existing technologies, this invention provides a multi-channel current conversion module for energy storage testing, which can simultaneously support current acquisition, calibration, and testing of multiple circuits, thereby improving testing efficiency and accuracy and reducing testing costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A multi-channel current conversion module for energy storage testing includes a constant current source unit, an input switching circuit, a current-to-voltage circuit, an operational amplifier adder circuit, and an inverting amplifier circuit.

[0008] The input switching circuit includes several branches. Each branch has a power input terminal including a constant current power input terminal and an external current input terminal. The external current input terminal is connected to an external power supply, and the constant current power input terminal is connected to a constant current source unit. The output terminal of each branch is connected to a current-to-voltage circuit. The current-to-voltage circuit is connected to an operational amplifier adder circuit, and the operational amplifier adder circuit is connected to an inverting amplifier circuit.

[0009] In a further technical solution, the constant current source unit includes a first operational amplifier, a transistor, a current transformer, a fourth resistor, and a tenth resistor;

[0010] The first non-inverting input of the first operational amplifier receives an analog signal, the first inverting input is connected to a current transformer through the tenth resistor, the output is connected to the base of a transistor through the fourth resistor, the emitter of the transistor is connected to the current transformer, the twelfth and thirteenth resistors are connected to the two ends of the second relay respectively, and the fourth pin of the current transformer is the constant current source output, which is connected to the input switching circuit.

[0011] In a further technical solution, the constant current source unit also includes a second relay, a twelfth resistor, and a thirteenth resistor;

[0012] One end of the twelfth and thirteenth resistors is connected in parallel to the second pin of the current transformer, and the other ends of the twelfth and thirteenth resistors are respectively connected to the two ends of the second relay.

[0013] In a further technical solution, the input switching circuit includes several first relays, each first relay having a first input terminal connected to the output terminal of a constant current source, a second input terminal connected to an external current, and an output terminal connected to a current-to-voltage conversion circuit.

[0014] In a further technical solution, the input switching circuit also includes several first microcontroller units, each of which is connected to one of the several first relays. The coil of the microcontroller unit generates an electric magnet to attract the contacts of the first relays to close.

[0015] In a further technical solution, the current-to-voltage circuit includes several current-to-voltage sub-circuits with identical structures. The output terminal of each input switching circuit branch is connected to several current-to-voltage sub-circuits, and the output terminals of the several current-to-voltage sub-circuits are connected to the operational amplifier adder circuit.

[0016] In a further technical solution, the current-to-voltage sub-circuit includes a second operational amplifier, a first potentiometer, and an eighth resistor;

[0017] The first inverting input terminal of the second operational amplifier is connected to the output terminal of the input switching circuit and the first terminal of the first potentiometer. The output terminal of the second operational amplifier is connected to the second terminal of the first potentiometer, the sliding terminal, and the first terminal of the eighth resistor. The second terminal of the eighth resistor is the output terminal of the current-to-voltage sub-circuit.

[0018] In a further technical solution, the operational amplifier adder circuit includes several second resistors, a third operational amplifier, a third resistor, and an eleventh resistor. The output terminals of several current-to-voltage sub-circuits in the current-to-voltage circuit are connected in series with several second resistors and then connected to the inverting input terminal of the third operational amplifier and the first terminal of the third resistor. The output terminal of the third operational amplifier is connected to the second terminal of the third resistor and serves as the adder output terminal.

[0019] In a further technical solution, the inverting amplifier circuit includes a fourth operational amplifier, a second potentiometer, a fifth resistor, a seventh resistor, and a ninth resistor; the adder output of the operational amplifier adder circuit is connected to the non-inverting input of the fourth operational amplifier through the ninth resistor, the inverting input of the fourth operational amplifier is connected to the output of the fourth operational amplifier through the second potentiometer, and the output of the fourth operational amplifier outputs the converted signal through the fifth resistor.

[0020] In a further technical solution, the constant current source unit also includes a digital-to-analog converter and a second microcontroller unit, wherein the output terminal of the second microcontroller unit is connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter is connected to the constant current source.

[0021] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0022] (1) Supports multiple signal inputs: Through the input switching circuit and the independent current to voltage circuit, the synchronous acquisition and conversion of multiple current signals can be realized.

[0023] (2) High integration: Through operational amplifier addition circuit and signal amplification circuit, multiple signals are combined and conditioned to a suitable sampling range, simplifying the subsequent processing flow.

[0024] (3) Self-calibration function: No external standard signal source is required, reducing the dependence on external devices. The standard signal is generated by MCU and DAC to realize the self-calibration of the circuit, which reduces the complexity and cost of the system and improves the flexibility and reliability of the system.

[0025] (4) By controlling the KiF relay, the constant current source outputs two currents to achieve the switching of current magnitude, so as to meet the calibration under different conditions.

[0026] Advantages of the present invention in additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0028] Figure 1 This is a schematic diagram of the multi-channel current conversion module for energy storage testing described in this utility model.

[0029] Figure 2 This is a circuit structure block diagram of the multi-channel current conversion module for energy storage testing described in this utility model.

[0030] Figure 3 This is a flowchart illustrating the multi-signal acquisition process of the multi-channel current conversion module for energy storage testing described in this utility model.

[0031] Figure 4 This is a flowchart illustrating the calibration process of the multi-channel current conversion module for energy storage testing described in this utility model. Detailed Implementation

[0032] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. It should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] To address the problems of large internal deviations, low efficiency, and complex calibration in existing technologies, this invention discloses a multi-channel current conversion module for energy storage testing, which can simultaneously support current acquisition, calibration, and testing of multiple circuits, thereby improving testing efficiency and accuracy and reducing testing costs.

[0035] This utility model discloses a multi-channel current conversion module for energy storage testing, such as... Figure 1 As shown, it includes a constant current source unit, an input switching circuit, a current-to-voltage circuit, an operational amplifier adder circuit, and an inverting amplifier circuit.

[0036] The input switching circuit includes several branches. Each branch has a power input terminal including a constant current power input terminal and an external current input terminal. The external current input terminal is connected to an external power supply, and the constant current power input terminal is connected to a constant current source unit. The output terminal of each branch is connected to a current-to-voltage circuit. The current-to-voltage circuit is connected to an operational amplifier adder circuit, and the operational amplifier adder circuit is connected to an inverting amplifier circuit.

[0037] The constant current source unit is used to generate a standard current signal for calibration purposes.

[0038] Multiple external current signals that need to be acquired are selected by the input switching circuit and enter the current-to-voltage circuit; the input switching circuit is used to support multiple signal inputs and select them to the corresponding current-to-voltage circuits respectively.

[0039] The current-to-voltage circuit is used to convert the selected current signal into a voltage signal. Each current signal is processed by an independent current-to-voltage circuit.

[0040] The op-amp adder circuit is used to combine multiple converted voltage signals and output them. Multiple voltage signals are superimposed by the op-amp adder circuit to form a single combined signal.

[0041] The inverting amplifier circuit is used to condition and amplify the combined signal through a single-stage inverting amplifier circuit, so that it reaches a range suitable for sampling.

[0042] In this embodiment, the circuit block diagram of the multi-channel current conversion module is as follows: Figure 2 As shown, specifically:

[0043] The constant current source unit includes a first operational amplifier U1A, a transistor Q1, a current transformer T1, a second relay KiF, a first resistor R1, a fourth resistor R4, a tenth resistor R10, a twelfth resistor R12, and a thirteenth resistor R13. The first non-inverting input of the first operational amplifier U1A receives an analog signal. The second non-inverting input is connected to the positive power supply VCC. The first inverting input is connected to the first terminal of the twelfth resistor R12, the first terminal of the thirteenth resistor R13, and the second pin of the current transformer through the tenth resistor R10. The second inverting input is connected to the negative power supply VSS. The output is connected to the base of transistor Q1 through the fourth resistor R4. The collector of transistor Q1 is connected to the positive power supply VCC through the first resistor R1. The emitter of transistor Q1 is connected to the first pin of the current transformer. The second terminal of the twelfth resistor R12 is connected to the first terminal of the second relay KiF. The second terminal of the thirteenth resistor R13 is connected to the second terminal of the second relay KiF and grounded. The third pin of the current transformer is grounded. The fourth pin of the current transformer is the output terminal of the constant current source and is connected to the first input terminal of several input switching circuits.

[0044] The input switching circuit includes several first relays K1, K2, ..., KN and a first microcontroller unit MCU-Kx. The first microcontroller unit MCU-Kx includes microcontroller units MUC-K1, MUC-K2, ..., MUC-KN. Microcontroller unit MUC-K1 controls relay K1, microcontroller unit MUC-K2 controls relay K2, and microcontroller unit MUC-KN controls relay KN. Specifically, the coil of the microcontroller unit generates magnetism to attract and close the contacts of the first relays. When the microcontroller unit MUC-K1 is at a low level, the normally closed contacts pins 11 and 13 of relay K1 are closed. When the microcontroller unit MUC-K1 is at a high level, its coil generates magnetism to close the normally open contacts pins 9 and 13 of relay K1. The normally open contacts of each relay are connected to the output terminal of a constant current source, the normally closed contacts are connected to an external current source, and the output terminal is connected to a current-to-voltage conversion circuit.

[0045] The current-to-voltage circuit comprises several structurally identical current-to-voltage sub-circuits. Each first relay is connected to one current-to-voltage sub-circuit. Each current-to-voltage sub-circuit includes a second operational amplifier U2A, a first potentiometer RV1, and an eighth resistor R8. Specifically, the first inverting input terminal of the second operational amplifier U2A is connected to the output terminal of the input switching circuit and the first terminal of the first potentiometer RV1. The second inverting input terminal is connected to the positive power supply VCC. The first non-inverting input terminal is grounded, and the second non-inverting input terminal is connected to the negative power supply VSS. The output terminal is connected to the second terminal and the sliding terminal of the first potentiometer RV1, and the first terminal of the eighth resistor R8. The second terminal of the eighth resistor R8 is the output terminal of the current-to-voltage sub-circuit.

[0046] In this embodiment, the input switching circuit operates as follows: the current signal output by the input switching circuit flows into the first inverting input terminal of operational amplifier U2A. Based on the virtual short and virtual open characteristics of the operational amplifier, the current flowing into the first inverting input terminal will generate a voltage drop across the first potentiometer RV1 and the eighth resistor R8. Due to the amplification effect of the operational amplifier, its output terminal will output a voltage signal proportional to the input current. Specifically, assuming the input current is I... in If the resistance of the first potentiometer RV1 is RV1, then the voltage generated on the first pin of the operational amplifier U2A is... This enables the conversion of current to voltage.

[0047] The operational amplifier adder circuit includes several second resistors R2, a third operational amplifier U2B, and a third resistor and an eleventh resistor R11. The output terminals of several current-to-voltage sub-circuits in the current-to-voltage circuit are respectively connected to the first terminals of several second resistors R2. The second terminals of several second resistors R2 are all connected to the inverting input terminal of the third operational amplifier U2B and the first terminal of the third resistor R3. The non-inverting input terminal of the third operational amplifier U2B is grounded through the eleventh resistor R11. The output terminal of the third operational amplifier U2B is connected to the second terminal of the third resistor R3 and serves as the adder output terminal.

[0048] In this embodiment, each current-to-voltage sub-circuit in the current-to-voltage circuit converts the input current signal into a voltage signal. These voltage signals are input to the operational amplifier adder circuit and connected to the inverting input terminal of the third operational amplifier U2B through the corresponding second resistor R2. According to Kirchhoff's current law, the current flowing into the inverting input terminal is the sum of the currents in each branch. Due to the virtual open circuit characteristic of the operational amplifier, the current flowing into the inverting input terminal is almost zero. Therefore, the voltage formed at the inverting input terminal by these currents is a weighted sum of the input voltage signals, and the weights are determined by the resistance value of the corresponding second resistor R2.

[0049] The operational amplifier circuit works as follows: the output of operational amplifier U2B is connected to the inverting input via a third resistor R3, forming a negative feedback loop. Based on the characteristics of the operational amplifier, the negative feedback mechanism adjusts the output voltage to keep the voltage difference between the inverting and non-inverting inputs close to zero. Because the non-inverting input is grounded via the eleventh resistor R11, its voltage is zero. Therefore, the output voltage adjusts according to the voltage change at the inverting input, making the voltage at the inverting input also approach zero.

[0050] Under the influence of negative feedback, the output voltage Vout is related to the voltage at the inverting input terminal. Satisfying Relationships ,in It is the voltage after the i-th input signal is converted by the current-to-voltage sub-circuit, and n is the number of input signals. That is, the output signal is the weighted sum of all input signals, realizing the addition operation function.

[0051] Using an operational amplifier adder circuit avoids the need for multiple independent circuits to process the superposition of multiple signals, thereby simplifying the overall circuit structure, reducing costs, and improving the reliability and stability of the system.

[0052] The inverting amplifier circuit includes a fourth operational amplifier U1B, a second potentiometer RV2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a ninth resistor R9. The adder output of the operational amplifier adder circuit is connected to the non-inverting input of the fourth operational amplifier U1B through the ninth resistor R9. The non-inverting input of the fourth operational amplifier U1B is also grounded through the seventh resistor R7. The inverting input of the fourth operational amplifier U1B is connected to the first terminal of the sixth resistor R6 and the first terminal of the second potentiometer RV2. The second terminal of the sixth resistor R6 is grounded. The output of the fourth operational amplifier U1B is connected to the second terminal of the second potentiometer RV2, the sliding terminal, and the first terminal of the fifth resistor R5. The second terminal of the fifth resistor R5 outputs the converted signal.

[0053] It should be noted that operational amplifiers have virtual short and virtual open characteristics. Virtual short makes the voltages at the non-inverting and inverting input terminals approximately equal, while virtual open makes the current flowing into the inverting input terminal almost zero.

[0054] In this embodiment, the inverting amplifier circuit receives the output signal from the operational amplifier adder circuit and applies it to the non-inverting input terminal of U1B through R9. Simultaneously, the non-inverting input terminal is grounded through R7, creating a voltage divider for the input signal. Assuming the input signal voltage is Vin, the inverting input terminal is grounded through R6, and RV2 is connected between the inverting input terminal and the output terminal, forming a negative feedback loop. When the voltage V+ at the non-inverting input terminal changes, due to the virtual short and virtual open characteristics, the voltage V- at the inverting input terminal will also change accordingly. ,in, This is the voltage at the inverting output terminal. This is the voltage at the non-inverting input terminal.

[0055] An inverting amplifier circuit amplifies the input signal and inverts the output signal.

[0056] Furthermore, in this embodiment, the multi-channel current conversion module also includes a digital-to-analog converter (DAC) and a second microcontroller unit (MUC-KiF). The output terminal of the second microcontroller unit (MUC-KiF) is connected to the input terminal of the DAC, and the output terminal of the DAC is connected to a constant current source. The second microcontroller unit (MCU-KiF) is used to control the gating signal, and the DAC is used to convert the gating signal into an analog signal to control the opening or closing of the constant current source. Specifically, when the second microcontroller unit (MCU-KiF) is at a low level, the relay KiF is in an open state; when the MCU-KiF is at a high level, the KiF contacts are closed by the principle of electromagnetism generated by its coil.

[0057] The multi-channel current conversion module proposed in this invention can support the acquisition, conversion and calibration of multiple current signals, thereby improving the efficiency and accuracy of energy storage testing, while reducing dependence on external equipment, realizing independent control, accurate measurement and efficient conversion of multiple currents, thus solving the shortcomings of the prior art.

[0058] The working principle of the multi-channel current conversion module with acquisition and calibration functions proposed in this utility model is as follows:

[0059] Multi-signal acquisition workflow, such as Figure 3 As shown, its working principle is as follows: The external current signal to be acquired is selected by the input switching circuit, and the selection signal is controlled by MCU-Kx. The external signal comes from multiple inputs from I_in1 to I_inN, and enters the circuit through the normally closed contacts 11 and 13 of relays K1 or KN for normal signal acquisition. Each signal is selected and controlled by the corresponding relays K1 to KN to convert the current signal into a voltage signal. This signal enters the operational amplifier adder circuit through independent resistors R2 to RN to combine the multiple signals for output. Finally, the combined signal is amplified by a first-stage inverting amplifier circuit U1B. The amplification factor can be adjusted by RV2 according to actual needs to condition and amplify the signal to a suitable range for signal sampling.

[0060] Signal calibration workflow, such as Figure 4 As shown, its working principle is as follows: The constant current source section of the calibration circuit mainly includes an MCU-KiF, a DAC, an operational amplifier circuit U1A, a transistor Q1, a current transformer T1, and a switchable resistor network. The current transformer T1 serves for isolation and protection. The calibration feature is that the MCU-KiF generates a digital sine wave signal through the DAC. After being converted into an analog signal by the DAC, the signal enters the constant current source circuit composed of U1A and transistor Q1, generating a constant current signal for calibration. The control flow is as follows: The MCU-K1 sends a signal to activate relay K1, causing contacts 11 and 13 to open and contacts 9 and 13 to close, allowing the constant current source to enter the subsequent circuit. Simultaneously, the MCU-KiF can also control the relay KiF between R12 and R13 to operate, allowing the constant current source to output 1mA and 2.5mA currents. Specifically, in the circuit, resistors R12 and R13 act as sampling resistors, maintaining a constant load current through a feedback mechanism. When the voltage across the sampling resistor R13 changes, it is directly fed back to the inverting input of the operational amplifier. The difference between the voltage across the sampling resistor and the non-inverting input is amplified by the operational amplifier, which controls the base current of the transistor, changes the internal resistance of the transistor, and thus changes the voltage drop between the emitter and collector. This keeps the voltage across the sampling resistor constant, thereby achieving the goal of a constant load current.

[0061] Only R13 is connected, and the calculation formula is: ;

[0062] When KiF is connected, R12 and R13 are connected in parallel, and the calculation formula is: This allows for switching of current magnitude to meet calibration requirements under different conditions.

[0063] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A multi-channel current conversion module for energy storage testing, characterized in that, include: Constant current source unit, input switching circuit, current to voltage conversion circuit, operational amplifier adder circuit, inverting amplifier circuit; The input switching circuit includes several branches. Each branch has a power input terminal including a constant current power input terminal and an external current input terminal. The external current input terminal is connected to an external power supply, and the constant current power input terminal is connected to a constant current source unit. The output terminal of each branch is connected to a current-to-voltage circuit. The current-to-voltage circuit is connected to an operational amplifier adder circuit, and the operational amplifier adder circuit is connected to an inverting amplifier circuit.

2. The multi-channel current conversion module for energy storage testing as described in claim 1, characterized in that, The constant current source unit includes a first operational amplifier, a transistor, a current transformer, a fourth resistor, and a tenth resistor; The first non-inverting input of the first operational amplifier receives an analog signal, the first inverting input is connected to a current transformer through the tenth resistor, the output is connected to the base of a transistor through the fourth resistor, the emitter of the transistor is connected to the current transformer, the twelfth and thirteenth resistors are connected to the two ends of the second relay respectively, and the fourth pin of the current transformer is the constant current source output, which is connected to the input switching circuit.

3. A multi-channel current conversion module for energy storage testing as described in claim 2, characterized in that, The constant current source unit also includes a second relay, a twelfth resistor, and a thirteenth resistor; One end of the twelfth and thirteenth resistors is connected in parallel to the second pin of the current transformer, and the other ends of the twelfth and thirteenth resistors are respectively connected to the two ends of the second relay.

4. A multi-channel current conversion module for energy storage testing as described in claim 1, characterized in that, The input switching circuit includes several first relays. The first input terminal of each first relay is connected to the output terminal of a constant current source, the second input terminal is connected to an external current, and the output terminal is connected to a current-to-voltage circuit.

5. A multi-channel current conversion module for energy storage testing as described in claim 4, characterized in that, The input switching circuit also includes several first microcontroller units, each of which is connected to one of the several first relays. The coil of the microcontroller unit generates an electric magnet to attract the contacts of the first relays to close.

6. A multi-channel current conversion module for energy storage testing as described in claim 1, characterized in that, The current-to-voltage circuit includes several current-to-voltage sub-circuits with identical structures. The output terminal of each input switching circuit branch is connected to several current-to-voltage sub-circuits, and the output terminals of the several current-to-voltage sub-circuits are connected to the operational amplifier adder circuit.

7. A multi-channel current conversion module for energy storage testing as described in claim 6, characterized in that, The current-to-voltage sub-circuit includes a second operational amplifier, a first potentiometer, and an eighth resistor; The first inverting input terminal of the second operational amplifier is connected to the output terminal of the input switching circuit and the first terminal of the first potentiometer. The output terminal of the second operational amplifier is connected to the second terminal of the first potentiometer, the sliding terminal, and the first terminal of the eighth resistor. The second terminal of the eighth resistor is the output terminal of the current-to-voltage sub-circuit.

8. A multi-channel current conversion module for energy storage testing as described in claim 1, characterized in that, The operational amplifier adder circuit includes several second resistors, a third operational amplifier, and an eleventh resistor. The output terminals of several current-to-voltage sub-circuits in the current-to-voltage circuit are connected in series with several second resistors and then connected to the inverting input terminal of the third operational amplifier and the first terminal of the third resistor. The output terminal of the third operational amplifier is connected to the second terminal of the third resistor and serves as the adder output terminal.

9. A multi-channel current conversion module for energy storage testing as described in claim 1, characterized in that, The inverting amplifier circuit includes a fourth operational amplifier, a second potentiometer, a fifth resistor, a seventh resistor, and a ninth resistor. The adder output of the operational amplifier adder circuit is connected to the non-inverting input of the fourth operational amplifier through the ninth resistor. The inverting input of the fourth operational amplifier is connected to the output of the fourth operational amplifier through the second potentiometer. The output of the fourth operational amplifier outputs the converted signal through the fifth resistor.

10. A multi-channel current conversion module for energy storage testing as described in claim 1, characterized in that, The constant current source unit also includes a digital-to-analog converter and a second microcontroller unit. The output terminal of the second microcontroller unit is connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter is connected to the constant current source.

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