Multi-channel signal source expansion circuit applied to CVM voltage calibration

Abstract

The invention provides a multi-channel signal source expansion circuit applied to CVM voltage calibration, which is used for expanding a multi-channel voltage source and comprises a power supply circuit, K groups of voltage division circuits, K groups of in-phase amplifiers and K groups of follower circuits. The method is convenient to operate, production efficiency is improved, cost is low, expansion and personalized adjustment are easy, if a higher voltage or a lower voltage is calibrated, only the number of PCBAs needs to be increased or decreased, only the number of PCBAs needs to be increased correspondingly, and before the method is added, the number of voltage strings of the CVM is not fixed and is generally customized, so that the number of the voltage strings of the CVM is not fixed. CVM calibration needs to be carried out by purchasing a plurality of expensive signal source devices or carrying out multi-point calibration on one CVM, after the CVM calibration method is added, the CVM can be calibrated at a time, and the CVM calibration method is convenient to adjust for CVMs of different voltage models.

Description

Technical Field

[0001] The invention belongs to the field of new energy batteries, and in particular relates to a multi-channel signal source expansion circuit applied to CVM voltage calibration. Background Art

[0002] Common fuel cell stacks on the market, such as hydrogen fuel cell stacks, are composed of hundreds of single cells connected in series, and the voltage patroller CVM is used to detect and calibrate the single cell voltage, impedance, etc. of the battery. When CVM performs voltage calibration, the number of output channels of the voltage source NG I of a single test device is limited, generally 24 channels. For example, if a 216-string CVM is calibrated for voltage, one method is to use the 24-channel signal source to perform modular step-by-step calibration on the CVM, and the calibration times are 216 / 24=9 times. Each calibration requires the CVM to be powered on and off and the connector to be replaced multiple times. If the voltage of the CVM is higher, the calibration times will be more, and the efficiency will be low. Another method is to purchase multiple 24-channel signal sources for cascading, similar to the first solution, then 9 signal sources need to be purchased, the signal source is expensive and occupies a large area, and the operation is not convenient. Summary of the invention

[0003] When CVM performs voltage calibration in the prior art, the number of voltage source output channels is limited. Each calibration requires the CVM to be powered on and off and the connector to be plugged in and replaced multiple times, or multiple 24-channel CVMs must be purchased. The present invention provides a multi-channel signal source expansion circuit for CVM voltage calibration.

[0004] In order to solve the technical problem, the present invention provides a multi-channel signal source expansion circuit for CVM voltage calibration, which is used to expand the multi-channel voltage source, and includes a power supply circuit, K groups of voltage divider circuits, K groups of in-phase amplifiers and K groups of follower circuits, where K is greater than or equal to 2;

[0005] The power supply circuit is used to provide working voltage to the amplifier circuit and the follower circuit;

[0006] Each group of voltage divider circuits includes resistors R1 to R9, the second end of the current resistor among the resistors R1 to R9 is connected to the first end of the next resistor, the first end of the resistor R1 and the second end of the resistor R9 are connected to the ground output end and the positive output end of one of the output channels of the multi-channel voltage source, and the K groups of voltage divider circuits are connected one-to-one to the K output channels of the multi-channel voltage source;

[0007] Each group of common-phase amplifiers includes 9 common-phase amplifiers, the amplification factor of the common-phase amplifiers is 9 times, and the input ends of the 9 common-phase amplifiers are connected to the second ends of resistors R1 to R9 in sequence;

[0008] Each group of follower circuits includes 9 follower circuits, the input end of each follower circuit is connected to the output end of the common-mode amplifier, and the output end of each follower circuit leads to an output end of the multi-channel signal source expansion circuit; the output end of the multi-channel signal source expansion circuit corresponding to the current group R9 is connected to the first end of the next group R1.

[0009] In the multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention, the multi-channel voltage source model is N83624-06-01.

[0010] In the multi-channel signal source expansion circuit used for CVM voltage calibration of the present invention, the power supply circuit also has K groups, and each group of power supply circuits supplies power to a group of common-phase amplifiers and a group of follower circuits corresponding to the group of common-phase amplifiers.

[0011] In the multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention, the common-phase amplifier includes an operational amplifier, a first feedback resistor, and a second feedback resistor. The common-phase input terminal of the operational amplifier is the input terminal of the common-phase amplifier, the two ends of the first feedback resistor are respectively connected to the output terminal and the inverting input terminal of the operational amplifier, one end of the second feedback resistor is connected to the inverting input of the operational amplifier, and the other end is connected to the first end of the resistor R1.

[0012] In the multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention, an RC low-pass filter for filtering low-frequency noise is also connected between the common-phase input terminal of the common-phase amplifier and the second end of the resistor R9, and the RC low-pass filter includes a first filter capacitor and a first filter resistor, and the two ends of the first filter resistor are respectively connected to the common-phase input terminal of the common-phase amplifier and the second end of the resistor R9; one end of the first filter capacitor is connected to the common-phase input terminal of the common-phase amplifier, and the other end is grounded.

[0013] In the multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention, a secondary low-pass filter is also connected between the common-phase amplifier and the follower circuit, and the secondary low-pass filter includes second to fourth filter resistors and second to third filter capacitors, and the second to fourth filter resistors are connected in series between the output end of the common-phase amplifier and the input end of the follower circuit in sequence; one end of the second filter capacitor is connected between the second to third filter resistors, and the other end is grounded; one end of the third filter capacitor is connected between the fourth filter resistor and the input end of the follower circuit, and the other end is grounded.

[0014] In the multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention, the follower circuit includes an operational amplifier, the non-inverting input terminal and the output terminal of the operational amplifier are the input terminal and the output terminal of the follower circuit, the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier, the inverting input terminal of the operational amplifier is also connected to one end of a de-noising capacitor, and the other end of the de-noising capacitor is connected between the third and fourth filter resistors.

[0015] In the multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention, a second RC low-pass filter for filtering low-frequency noise is also connected between the output end of the follower circuit and the output end of the corresponding multi-channel signal source expansion circuit, and the second RC low-pass filter includes a fourth filter capacitor and a fifth filter resistor; one end of the fifth filter resistor is connected to the output end of the follower circuit, and the other end is respectively connected to the output end of the multi-channel signal source expansion circuit and one end of the fourth filter capacitor, and the other end of the fourth filter capacitor is grounded.

[0016] In the multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention, the multi-channel voltage source is a 24-channel voltage source, K=24, and the corresponding circuits of each adjacent 4 output channels of the 24-channel voltage source are integrated into one PCBA, forming a total of 6 PCBAs, and each PCBA outputs 36 voltages.

[0017] In general, the above technical solution conceived by the present invention has beneficial effects compared with the prior art: it is easy to operate and improves production efficiency. Previously, when calibrating high-voltage CVM, if 24 channels were used to calibrate 216 strings of CVM, it was necessary to calibrate 9 times and each time the power had to be turned on and off and the connector had to be plugged in and out, which was extremely inefficient.

[0018] Low cost. During calibration, 9 NG I devices need to be purchased, which are expensive. This solution only requires customization of 6 PCBAs and then integration into a housing, which is low cost.

[0019] Easy to expand and personalize. If you want to calibrate a higher voltage or a lower voltage, you only need to increase or decrease the number of PCBAs.

[0020] Before the invention, since the number of voltage strings of CVM is not fixed and is generally customized, it is necessary to purchase multiple expensive signal source devices for calibration or perform multi-point calibration on one CVM. After the invention, the CVM can be calibrated at one time, and the invention is convenient for adjustment for CVMs of different voltage models. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A schematic diagram of a multi-channel signal source expansion circuit for CVM voltage calibration provided in an embodiment of the present application;

[0022] Figure 2 A circuit diagram corresponding to the first output channel of a multi-channel signal source expansion circuit for CVM voltage calibration provided in an embodiment of the present application;

[0023] Figure 3 A circuit diagram corresponding to the first output channel of a multi-channel signal source expansion circuit for CVM voltage calibration provided in an embodiment of the present application;

[0024] Figure 4 It is a cascade schematic diagram of the PCBA provided in the application embodiment. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] refer to Figure 1-3 The multi-channel signal source expansion circuit for CVM voltage calibration in this embodiment only illustrates part of the circuit, and the other parts can be referred to Figure 2 , Figure 3 . Used to expand the 24-channel voltage source. The 24-channel voltage source NG I model is N83624-06-01.

[0027] The multi-channel signal source expansion circuit of this embodiment includes a power supply circuit, 24 groups of voltage divider circuits, 24 groups of in-phase amplifiers and 24 groups of follower circuits.

[0028] The power supply circuit is used to provide working voltage for the amplifier circuit and the follower circuit. In this embodiment, the power supply circuit is responsible for converting the power supply of the DC power supply to the power supply voltage of the 36V DC power supply, thereby supplying power to the amplifier circuit. The power supply circuit adopts an isolated DC-DC, which is lower than the power supply voltage of the operational amplifier OPx. The specific implementation method for ensuring the safety of the power supply system can be referred to Figure 2 , Figure 3 In this embodiment, there are 24 power supply circuits, each of which supplies power to a group of common-phase amplifiers and a group of follower circuits corresponding to the group of common-phase amplifiers. However, the present invention is not limited to this power supply method. For example, a group of power supply circuits can be used to supply power to multiple groups of common-phase amplifiers and multiple groups of follower circuits corresponding to the group of common-phase amplifiers. However, the present invention is not limited to this power supply method. Figure 2 , Figure 3 This power supply method is more effective.

[0029] Each group of voltage divider circuits includes resistors R1 to R9, the second end of the current resistor among the resistors R1 to R9 is connected to the first end of the next resistor, the first end of the resistor R1 and the second end of the resistor R9 are connected to the ground output end and the positive output end of one of the output channels of the multi-channel voltage source, and the 24 groups of voltage divider circuits are connected one-to-one to the 24 output channels of the multi-channel voltage source. The voltage divider circuit divides the output signal of a single channel of the signal source into 9 equal parts through resistors R1, R2...R9, and the voltage of each equal part is 1 / 9 of the output voltage of the signal source. High-precision precision resistors R1, R2...R9 are used to ensure the consistency of the equally divided voltage.

[0030] Each group of common-phase amplifiers includes 9 common-phase amplifiers, and the amplification factor of the common-phase amplifiers is 9. The input ends of the 9 common-phase amplifiers are connected to the second ends of resistors R1 to R9 in sequence. Figure 1 In the figure, operational amplifiers OP1, OP2…OP9 are high-precision rail-to-rail operational amplifiers with a supply voltage of up to 45V. A common-phase amplifier is used to amplify the voltage evenly divided by the voltage divider circuit by 9 times through the common-phase amplifier. After amplification, the evenly divided voltages are consistent with the signal source voltage. Rinx and Rfx are operational amplifier feedback networks, and the amplification factor A=1+Rfx / Ri nx. After passing through the amplification circuit, the single-channel input signal is converted into a 9-channel output, and the voltage difference between the front and rear channels is consistent with the input signal. High-precision precision resistors Rinx and Rfx are used to ensure the accuracy of the amplification factor.

[0031] Each group of follower circuits includes 9 follower circuits, the input end of each follower circuit is connected to the output end of the in-phase amplifier, and the output end of each follower circuit leads to an output end of the multi-channel signal source expansion circuit; the output end of the multi-channel signal source expansion circuit corresponding to the current group R9 is connected to the first end of the next group R1. Figure 1 Among them, OP10, OP11…OP18 are high-precision rail-to-rail operational amplifiers like OP1, OP2…OP9, with a supply voltage of up to 45V. OP10, OP11…OP18 are used for voltage following. The output voltage of the operational amplifier is consistent with the input voltage. The purpose is to enhance the driving ability of the output signal, that is, the driving ability of OUTPUT: CH1…CH9, improve the performance and stability of the circuit, and make the lower circuit work better.

[0032] The following Figure 2 Take resistor R9 and the corresponding circuit as an example.

[0033] The common-phase amplifier includes an operational amplifier U9A, a first feedback resistor R27, and a second feedback resistor R18. The model of the operational amplifier U9A is MCP6V52. The first feedback resistor R27 and the second feedback resistor R18 are 160KΩ and 20KΩ, respectively. The common-phase input terminal of the operational amplifier U9A is the input terminal of the common-phase amplifier. The two ends of the first feedback resistor R27 are respectively connected to the output terminal and the inverting input terminal of the operational amplifier U9A. One end of the second feedback resistor R18 is connected to the inverting input of the operational amplifier, and the other end is connected to the first end of the resistor R1 for grounding.

[0034] An RC low-pass filter for filtering low-frequency noise is also connected between the non-inverting input terminal of the non-inverting amplifier and the second end of the resistor R9. The RC low-pass filter includes a first filter capacitor C229 and a first filter resistor R261. The sizes of the first filter capacitor C229 and the first filter resistor R261 are 22nF and 18KΩ respectively. The two ends of the first filter resistor R261 are respectively connected to the non-inverting input terminal of the non-inverting amplifier and the second end of the resistor R9; one end of the first filter capacitor C229 is connected to the non-inverting input terminal of the non-inverting amplifier, and the other end is grounded.

[0035] A secondary low-pass filter is also connected between the in-phase amplifier and the follower circuit, and the secondary low-pass filter further filters out the high-frequency noise in the circuit. The secondary low-pass filter includes the second to fourth filter resistors R36, R45, R54 and the second to third filter capacitors C34, C45, whose sizes are 3.74KΩ, 11.8KΩ, 6.65KΩ, 2.2nF, and 330pF respectively. The second to fourth filter resistors R36, R45, and R54 are connected in series between the output end of the in-phase amplifier and the input end of the follower; one end of the second filter capacitor C34 is connected between the second to third filter resistors R36 and R45, and the other end is grounded; one end of the third filter capacitor C45 is connected between the fourth filter resistor R54 and the input end of the follower circuit, and the other end is grounded.

[0036] The follower circuit includes an operational amplifier U9B, which is consistent with the operational amplifier U9A. The in-phase input terminal and output terminal of the operational amplifier U9B are the input terminal and output terminal of the follower circuit, and the inverting input terminal of the operational amplifier U9B is connected to the output terminal of the operational amplifier U9B. The inverting input terminal of the operational amplifier U9B is also connected to one end of a de-noising capacitor C54, and the other end of the de-noising capacitor C54 is connected between the third and fourth filter resistors R45 and R54. The size of the de-noising capacitor C54 is 2.2nF, and the de-noising capacitor C54 can further suppress the noise of the follower circuit part.

[0037] A second RC low-pass filter for filtering low-frequency noise is also connected between the output end of the follower circuit and the output end of the corresponding multi-channel signal source expansion circuit. The second RC low-pass filter includes a fourth filter capacitor C67 and a fifth filter resistor R64, whose sizes are 0.1μF and 10 ohms respectively; one end of the fifth filter resistor R64 is connected to the output end of the follower circuit, and the other end is respectively connected to the output end of the multi-channel signal source expansion circuit and one end of the fourth filter capacitor C67, and the other end of the fourth filter capacitor C67 is grounded.

[0038] The present invention can make the above circuit into a PCBA, each PCBA outputs 36 voltages, and 6 PCBAs are connected in series, with a total of 36*6=216 series. The module cascade diagram is shown in FIG. Figure 4 .

[0039] The multi-channel signal source expansion circuit applied to CVM voltage calibration of the present invention expands each external input signal source to become a multi-channel signal source output, and the output signal source is linearly related to the input signal source, and each output signal is basically consistent with the input signal. When the input signal voltage is adjusted, the multi-channel output voltage is also adjusted accordingly. For example, when calibrating the voltage of 216 strings of CVM, the circuit converts the input voltage of each channel into 9-channel voltage output. When 24 channels are input at the same time, the number of output strings is as high as 216 strings, and the voltage calibration of the high-voltage CVM can be performed at one time.

[0040] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0041] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] It will be easily understood by those skilled in the art that 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0043] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0044] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] It will be easily understood by those skilled in the art that 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-channel signal source expansion circuit for CVM voltage calibration, used for expanding a multi-channel voltage source, characterized in that: It comprises a power supply circuit, K groups of voltage divider circuits, K groups of common-mode amplifiers and K groups of follower circuits, where K is greater than or equal to 2; The power supply circuit is used to provide working voltage to the amplifier circuit and the follower circuit; Each group of voltage divider circuits includes resistors R1 to R9 of the same size, the second end of the current resistor among the resistors R1 to R9 is connected to the first end of the next resistor, the first end of the resistor R1 and the second end of the resistor R9 are connected to the ground output end and the positive output end of one of the output channels of the multi-channel voltage source, and the K groups of voltage divider circuits are connected one-to-one to the K output channels of the multi-channel voltage source; Each group of common-phase amplifiers includes 9 common-phase amplifiers, the amplification factor of the common-phase amplifiers is 9 times, and the input ends of the 9 common-phase amplifiers are connected to the second ends of resistors R1 to R9 in sequence; Each group of follower circuits includes 9 follower circuits, the input end of each follower circuit is connected to the output end of the common-mode amplifier, and the output end of each follower circuit leads to an output end of the multi-channel signal source expansion circuit; the output end of the multi-channel signal source expansion circuit corresponding to the current group R9 is connected to the first end of the next group R1.

2. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 1, characterized in that: The power supply circuit also has K groups, and each group of power supply circuits supplies power to a group of common-phase amplifiers and a group of follower circuits corresponding to the group of common-phase amplifiers.

3. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 1, characterized in that: The common-phase amplifier includes an operational amplifier, a first feedback resistor, and a second feedback resistor. The common-phase input terminal of the operational amplifier is the input terminal of the common-phase amplifier. The two ends of the first feedback resistor are respectively connected to the output terminal and the inverting input terminal of the operational amplifier. One end of the second feedback resistor is connected to the inverting input of the operational amplifier, and the other end is connected to the first end of the resistor R1.

4. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 1, characterized in that: An RC low-pass filter for filtering low-frequency noise is also connected between the common-phase input terminal of the common-phase amplifier and the second end of the resistor R9. The RC low-pass filter includes a first filter capacitor and a first filter resistor. The two ends of the first filter resistor are respectively connected to the common-phase input terminal of the common-phase amplifier and the second end of the resistor R9; one end of the first filter capacitor is connected to the common-phase input terminal of the common-phase amplifier, and the other end is grounded.

5. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 1, characterized in that: A secondary low-pass filter is also connected between the in-phase amplifier and the follower circuit, and the secondary low-pass filter includes second to fourth filter resistors and second to third filter capacitors, and the second to fourth filter resistors are sequentially connected in series between the output end of the in-phase amplifier and the input end of the follower circuit; One end of the second filter capacitor is connected between the second and third filter resistors, and the other end is grounded; one end of the third filter capacitor is connected between the fourth filter resistor and the input end of the follower circuit, and the other end is grounded.

6. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 5, characterized in that: The follower circuit includes an operational amplifier, the non-inverting input terminal and the output terminal of the operational amplifier are the input terminal and the output terminal of the follower circuit, the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier, the inverting input terminal of the operational amplifier is also connected to one end of a de-noising capacitor, and the other end of the de-noising capacitor is connected between the third and fourth filter resistors.

7. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 1, characterized in that: A second RC low-pass filter for filtering low-frequency noise is also connected between the output end of the follower circuit and the output end of the corresponding multi-channel signal source expansion circuit, and the second RC low-pass filter includes a fourth filter capacitor and a fifth filter resistor; One end of the fifth filter resistor is connected to the output end of the follower circuit, and the other end is respectively connected to the output end of the multi-channel signal source expansion circuit and one end of the fourth filter capacitor, and the other end of the fourth filter capacitor is grounded.

8. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 1, characterized in that: The multi-channel voltage source is a 24-channel voltage source, K=24, and the corresponding circuits of each of the adjacent four output channels of the 24-channel voltage source are integrated on one PCBA, forming a total of six PCBAs, each of which outputs 36 voltages.

9. The multi-channel signal source expansion circuit for CVM voltage calibration according to claim 8, characterized in that: The model of the 24-channel voltage source is N83624-06-01.

Images