CN205581212U - Power battery internal resistance on -line monitoring system - Google Patents

Abstract

The utility model discloses an online monitoring system for internal resistance of a power battery, which is composed of a power conversion unit, a signal generation unit, a detection circuit unit, a signal acquisition unit and a main control unit. The detection circuit unit includes a DC blocking module, a three-item selection switch K, a four-wire standard resistor r1, a four-wire standard resistor r2 and a reference resistor r0. The signal generation unit sends out the driving signal, and realizes the reference voltage value U of the reference resistance r0, a voltage value U ₁ corresponding to the four-wire standard resistance r1, a voltage value U ₂ corresponding to the four-wire standard resistance r2 and the waiting time through the detection circuit unit. The detection of a voltage value _U3 corresponding to the power battery E of the four-wire fixture is sensed by the signal acquisition unit to the main control unit to realize the detection of the internal resistance of the power battery. The utility model can complete the online detection of the internal resistance of the power battery without collecting the AC signal, and has little damage to the power battery; the measuring circuit can eliminate the influence of the contact resistance and the wire resistance on the measurement result, and has reliable performance.

Description

A power battery internal resistance online monitoring system

technical field

The utility model relates to the technical field of power battery monitoring, in particular to an online monitoring system for the internal resistance of a power battery.

Background technique

Power batteries are widely used in fields such as electric vehicles, electric tools, substations and mobile base stations. The performance and service life of the power battery are closely related to the internal resistance of the battery. As the battery ages, the internal resistance of the battery changes continuously, and the service life and power supply capacity of the battery will change. By detecting the internal resistance of the battery, changes in battery performance can be found in time, which lays the foundation for formulating a reasonable battery management strategy.

For battery internal resistance detection, currently commonly used methods include: DC discharge internal resistance detection method and AC signal injection detection method. The DC discharge internal resistance detection method, although the hardware circuit structure is simple, the circuit is stable, and the anti-interference ability is strong, but in order to achieve high detection accuracy, the resistance value of the detection resistor must be small, and the voltage of the power battery is generally high. In this way, when the circuit is connected, the discharge current of the battery will be very large, and long-term use will greatly reduce the service life of the battery, and the high-current discharge itself is also very dangerous, and the related equipment is also relatively large; at the same time, the internal resistance of the battery is too large. , it cannot provide enough instantaneous constant current, which will affect the accuracy of measurement. Although the AC signal injection detection method does not cause large current discharge like the DC discharge internal resistance detection method. However, the actual battery model is very complex, and its internal capacitance and inductance characteristics are sometimes particularly prominent. The added AC signal is prone to distortion, and the anti-interference performance is relatively poor. Ultimately, it is necessary to achieve high detection accuracy. The signal processing capability of the system is very demanding. Moreover, it is complicated and difficult to generate the required stable AC signal. Therefore, most of the high-precision battery internal resistance testing instruments currently on the market are large-scale special battery internal resistance testing equipment, and most of these equipment are bulky and heavy.

In order to overcome the shortcomings of the above AC signal injection detection method, the utility model patent with the announcement number CN101685117 and the name "Method for Measuring the Internal Resistance of the Battery" proposes a method for measuring the internal resistance of the battery. The battery, the sampling resistor and the isolated DC capacitor are connected in series; the voltage response signals at both ends of the battery and the sampling resistor are respectively extracted through an active band-pass filter; the extracted signal passes through the peak detection unit to obtain its peak voltage; then the peak voltage is amplified , sent to AD and processed by the microcontroller to calculate the internal resistance. Although this patent makes the device simple and small, and can reduce the influence of noise and distortion, the contact resistance or wire resistance in the entire circuit will have a great impact on the accuracy of the detection results during measurement.

Utility model content

The technical problem to be solved by the utility model is that there are problems such as low measurement accuracy, large damage to the battery and large equipment volume in the internal resistance detection process of the existing power battery, and an online monitoring system for the internal resistance of the power battery is provided.

In order to solve the above problems, the utility model is achieved through the following technical solutions:

An online monitoring system for the internal resistance of a power battery, which is composed of a power conversion unit, a signal generation unit, a detection circuit unit, a signal acquisition unit and a main control unit; the input end of the power conversion unit is connected to an external power supply, and the output end of the power conversion unit is connected to the Signal generation unit, signal acquisition unit and main control unit; the above-mentioned detection circuit unit includes a DC blocking module, a three-item selection switch K, a four-wire standard resistor r1, a four-wire standard resistor r2 and a reference resistor r0; the input terminal of the DC blocking module is connected to The output terminal of the signal generating unit and the output terminal of the DC blocking module are connected to the input terminal of the three-item selection switch K; the first terminal a1 of the four-wire standard resistor r1 is connected to the first output terminal of the three-item selection switch K, and the four-wire standard resistor r2 The first end a2 of the three-item selection switch K is connected to the second output end of the three-item selection switch K, and the first end a3 of the four-wire fixture power battery E to be tested is connected to the third output end of the three-item selection switch K; the second end of the four-wire standard resistance r1 Terminal b1, the second terminal b2 of the four-wire standard resistance r2, the second terminal b3 of the four-wire fixture power battery E to be tested, one end of the reference resistor r0, the reference input terminal of the signal acquisition unit and the reference input terminal of the main control unit are connected ; The third terminal c1 of the four-wire standard resistor r1, the third terminal c2 of the four-wire standard resistor r2, the third terminal c3 of the power battery E of the four-wire fixture to be tested and the other end of the reference resistor r0 are connected to the ground of the signal generating unit at the same time terminal connection; the fourth end d1 of the four-wire standard resistance r1, the fourth end d2 of the four-wire standard resistance r2, and the fourth end d3 of the four-wire fixture power battery E to be tested are connected to the measurement input end of the signal acquisition unit; the signal acquisition unit The output terminal of the main control unit is connected with the measurement input terminal.

In the above scheme, the signal generating unit includes a precision waveform generator U1, a precision power operational amplifier U2, and a precision high-current operational amplifier U3; the power terminals of the precision waveform generator U1, the precision power operational amplifier U2, and the precision high-current operational amplifier U3 are all It is connected with the output terminal of the power conversion unit; the output terminal of the precision waveform generator U1 is connected with the input terminal of the precision power operational amplifier U2, and the output terminal of the precision power operational amplifier U2 is connected with the input terminal of the precision high-current operational amplifier U3, and the precise high-current The output terminal of the operational amplifier U3 forms the output terminal of the signal generating unit, and is connected with the input terminal of the DC blocking module.

In the above scheme, the signal acquisition unit includes high-precision instrumentation amplifiers U4 and U5, precision low-offset high-impedance operational amplifiers U6 and U7, balanced modem U8, and precision low-offset low-drift operational amplifier U9; high-precision instrumentation amplifiers U4 and U5, precision The power supply terminals of the low-offset high-impedance operational amplifiers U6 and U7, the balanced modem U8, and the precision low-offset low-drift operational amplifier U9 are all connected to the output end of the power conversion unit; the input end of the high-precision instrumentation amplifier U4 forms the measurement of the signal acquisition unit The input terminal is connected to the fourth terminal d1 of the four-wire standard resistor r1, the fourth terminal d2 of the four-wire standard resistor r2, and the fourth terminal d3 of the four-wire fixture power battery E to be tested; the output of the high-precision instrument amplifier U4 The terminal is connected to the input terminal of the precision low offset high impedance operational amplifier U6; the output terminal of the precision low offset high impedance operational amplifier U6 is connected to the measurement input terminal of the balanced modem U8; the input terminal of the high precision instrumentation amplifier U5 forms the reference input of the signal acquisition unit and connected to one end of the reference resistor r0; the output of the high-precision instrumentation amplifier U5 is connected to the input of the precision low-offset high-impedance operational amplifier U7; the output of the precision low-offset high-impedance operational amplifier U7 is connected to the reference of the balanced modem U8 Input terminal; the output terminal of the balanced modem U8 is connected to the input terminal of the precision low offset low drift operational amplifier U9, and the output terminal of the precision low offset low drift operational amplifier U9 forms the output terminal of the signal acquisition unit, and is connected with the measurement input terminal of the main control unit connect.

In the above solution, the power conversion unit includes DC-DC voltage conversion regulators U10 and U11, and a low-dropout linear regulator U12; the input terminal of the DC-DC voltage conversion regulator U10 is connected to an external power supply, and the DC-DC voltage The output terminal of the conversion regulator U10 is connected to the signal generation unit, the signal acquisition unit and the input terminal of the DC-DC voltage conversion regulator U11, and the output terminal of the DC-DC voltage conversion regulator U11 is connected to the low-dropout linear regulator U12 The input end of the low dropout linear voltage regulator U12 is connected to the main control unit.

Compared with the prior art, the power battery internal resistance online monitoring system designed by the utility model is added between the power battery and the battery management system controller; the online detection of the power battery internal resistance can be completed without collecting AC signals , less damage to the power battery; the measurement circuit can eliminate the influence of contact resistance and wire resistance on the measurement results, and the performance is reliable; there are a variety of communication modules for easy communication and integration with other systems, which can be controlled by LCD touch display and Android mobile phones, and for The state of health of the battery makes a graded alarm.

Description of drawings

Figure 1 is a schematic structural diagram of an online monitoring system for the internal resistance of a power battery.

Fig. 2 is a schematic diagram of the circuit principle of the signal generation unit of the power battery internal resistance online monitoring system.

Fig. 3 is a schematic diagram of the circuit principle of the signal acquisition unit of the power battery internal resistance online monitoring system.

Fig. 4 is a schematic diagram of the circuit principle of the power conversion unit of the power battery internal resistance online monitoring system.

Fig. 5 is a circuit block diagram of the main control unit of the power battery internal resistance online monitoring system.

detailed description

An online monitoring system for the internal resistance of a power battery, as shown in Figure 1, is mainly composed of a signal generation unit, a detection circuit unit, a signal acquisition unit, a power conversion unit and a main control unit. There are two loops in the system as a whole, namely the drive loop and the induction loop.

The detection circuit unit includes a DC blocking module, a three-item selection switch K, a four-wire standard resistor r1, a four-wire standard resistor r2, a reference resistor r0, and a four-wire fixture power battery E to be tested. The input terminal of the DC blocking module is connected to the output terminal of the signal generating unit, and the output terminal of the DC blocking module is connected to the input terminal of the three-item selection switch K. The first terminal a1 of the four-wire standard resistor r1 is connected to the first output terminal of the three-item selection switch K, and the first terminal a2 of the four-wire standard resistor r2 is connected to the second output terminal of the three-item selection switch K. The first terminal a3 of the battery E is connected to the third output terminal of the three-item selection switch K. The second terminal b1 of the four-wire standard resistor r1, the second terminal b2 of the four-wire standard resistor r2, the second terminal b3 of the power battery E of the four-wire fixture to be tested, one end of the reference resistor r0, the reference input terminal of the signal acquisition unit and The reference input of the main control unit is connected. The third terminal c1 of the four-wire standard resistor r1, the third terminal c2 of the four-wire standard resistor r2, the third terminal c3 of the four-wire fixture power battery E to be tested, and the other end of the reference resistor r0 are simultaneously connected to the ground terminal of the signal generating unit connect. The fourth end d1 of the four-wire standard resistance r1, the fourth end d2 of the four-wire standard resistance r2, and the fourth end d3 of the four-wire fixture power battery E to be tested are connected to the measurement input end of the signal acquisition unit; the output end of the signal acquisition unit Connect to the measuring input of the main control unit. The signal is selected to be input to the first channel, or the second channel, or the third channel by the three-item selection switch K. The signal from the first channel is input to the reference resistor r0 through the four-wire standard resistor r1; the signal from the second channel is input to the reference resistor r0 through the four-wire standard resistor r2; the signal from the third channel is input to the four-wire fixture to be tested The power battery E is input into the reference resistor r0. The reference resistor r0 is connected to the signal generating unit. The four-wire standard resistor r1, the four-wire standard resistor r2 and the output signal of the power battery E of the four-wire fixture to be tested are input to the signal acquisition unit; at the same time, the reference signal output terminal of the reference resistor r0 is connected to the signal acquisition unit and the main control unit. See Figure 1.

The signal generation unit includes a precision waveform generator U1, a precision power operational amplifier U2, a precision high-current operational amplifier U3, and peripheral resistors R1-R14 and capacitors C1-C5. The input terminal of the precision waveform generator U1 is connected to the output terminal of the power conversion unit, the output terminal of the precision waveform generator U1 is connected to the precision high-current operational amplifier U3 through the precision power operational amplifier U2, and the output terminal of the precision high-current operational amplifier U3 is through a DC blocking The modules are serially connected into the detection circuit unit. Among them, the precision waveform generator U1 is used to generate the AC signal required by the whole system, and the precision power operational amplifier U2 is used to improve its load capacity, and it is transmitted to the precision high-current operational amplifier U3 to generate AC current. The AC current is serially input to the detection circuit unit through the DC blocking module. See Figure 2.

The signal acquisition unit includes high-precision instrumentation amplifiers U4 and U5, precision low-offset high-impedance operational amplifiers U6 and U7, balanced modem U8, precision low-offset low-drift operational amplifier U9, and peripheral resistors R1-1 to R1-7 and capacitor C1 -1 to C1-7, resistors R2-1 to R2-7, capacitors C2-1 to C2-7, resistors R15-R22 and capacitors C6-C9. The power supply terminals of high-precision instrumentation amplifiers U4 and U5, precision low-offset high-impedance operational amplifiers U6 and U7, balanced modem U8, and precision low-offset low-drift operational amplifier U9 are all connected to the output terminal of the power conversion unit.

The input terminal of the high-precision instrumentation amplifier U4 forms the measurement input terminal of the signal acquisition unit, and is simultaneously connected with the fourth terminal d1 of the four-wire standard resistor r1, the fourth terminal d2 of the four-wire standard resistor r2, and the power battery E of the four-wire fixture to be tested The fourth terminal d3 is connected. The input terminal of the high-precision instrument amplifier U4 is specifically connected to the fourth terminal d3 of the power battery E of the four-wire fixture to be tested or the fourth terminal d1 of the four-wire standard resistor r1 or the fourth terminal d2 of the four-wire standard resistor r2. Here, there are three items Select switch K to select. The output end of the high-precision instrumentation amplifier U4 is connected to the input end of the precision low-offset high-impedance operational amplifier U6; the output end of the precision low-offset high-impedance operational amplifier U6 is connected to the measurement input end of the balanced modem U8. The input end of the high-precision instrumentation amplifier U5 forms the reference input end of the signal acquisition unit, and is connected with one end of the reference resistor r0. The output terminal of the high-precision instrumentation amplifier U5 is connected to the input terminal of the precision low-offset high-impedance operational amplifier U7; the output terminal of the precision low-offset high-impedance operational amplifier U7 is connected to the reference input terminal of the balanced modem U8. The output end of the balanced modem U8 is connected to the input end of the precision low offset low drift operational amplifier U9, and the output end of the precision low offset low drift operational amplifier U9 forms the output end of the signal acquisition unit and is connected to the measurement input end of the main control unit. High-precision instrumentation amplifiers U4 and U5 are used to amplify the signals in the circuit, and the amplified signals are filtered through precision low-offset high-impedance operational amplifiers U6 and U7, and the output signals of precision low-offset high-impedance operational amplifiers U6 and U7 are input to balanced modem U8. A balanced modem U8 multiplies the two output signals and the resulting signal is filtered by a precision low offset low drift operational amplifier U9 before being input to the main control unit. See Figure 3.

The power conversion unit includes DC-DC voltage conversion regulators U10 and U11, a low-dropout linear regulator U12, and peripheral resistors R23, LED D1, capacitors C10 to C12, and electrolytic capacitors C01 to C03. Among them, the input terminal of the DC-DC voltage conversion regulator U10 is connected to an external power supply, and the output terminal of the DC-DC voltage conversion regulator U10 is connected to the input terminal of another DC-DC voltage conversion regulator U11 and the signal generation in the system unit and signal acquisition unit; the input terminal of the low dropout linear regulator U12 is connected to the output terminal of the DC-DC voltage conversion regulator U11, and the output terminal of the low dropout linear regulator U12 is connected to the main control unit in the system. The input end of the power conversion unit is connected to the external power supply, and the output end of the power conversion unit is connected to each unit that needs power supply. The power of the external power supply passes through the power conversion unit to become the +/-15V, 5V and 3.3V voltage required by the circuit, so as to provide to each unit, in which the signal generation unit and the signal acquisition unit need +/-15V V+, V- voltage. The main control unit is connected to 5V and 3.3V. See Figure 4.

After the main control unit obtains the data from the signal acquisition unit, it processes and analyzes the data, and touches the display and alarms through the LCD touch module and the level alarm module, and can also communicate with the battery through the CAN communication module, Bluetooth communication module and serial communication module Management system, Android phone and computer interact. See Figure 5.

In the online monitoring method of the internal resistance of the power battery implemented by the above system, the AC signal generated by the signal generating unit is injected into the detection circuit unit through the DC blocking module. In the detection circuit unit, the three-item selection switch K first selects the first path, and the signal acquisition unit can collect a voltage value U ₁ corresponding to the four-wire standard resistance r1; then the three-item selection switch K selects the second path, and the signal The acquisition unit can acquire a voltage value U ₂ corresponding to the four-wire standard resistance r2; the last three selection switches K select the third channel, and the signal acquisition unit can acquire a voltage value corresponding to the power battery E of the four-wire fixture to be tested U ₃ . A corresponding reference voltage value U can be obtained by collecting the voltage of the reference resistor r0. Since the AC current in the circuit remains unchanged, and there are resistance r on the line and the internal resistance re of the battery, according to the circuit principle:

$\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; u</span>}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; r</span>}}{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

$\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; u</span>}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; r</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

From (1), (2) can get:

$\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; r</span>}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Then by combining (3) and (4), we can get:

$\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Among them, _r1 is the resistance value of the four-wire standard resistor r1; _r2 is the resistance value of the four-wire standard resistor r2.

Afterwards, according to the formula, the main chip processes, calculates and analyzes the collected data through software programming to obtain the corresponding internal resistance value, and displays, judges and alarms.

The above-mentioned content is only the preferred embodiment of the utility model, although the utility model has been described in detail, for those skilled in the art, various changes can be made to it in terms of form and details. Changes, these changes should also be regarded as the protection scope of the present utility model.

Claims (4)

1. an electrokinetic cell internal resistance on-line monitoring system, it is characterised in that: by power conversion unit, Signal generation unit, testing circuit unit, signal gathering unit and main control unit composition；Power supply becomes The input changing unit is connected with external power source, and the outfan of power conversion unit connects signal and produces single Unit, signal gathering unit and main control unit；

Above-mentioned testing circuit unit include every straight module, three select switch K, four line standard resistance r1, Four line standard resistance r2 and reference resistance r0；

Input every straight module connects the outfan of signal generation unit, and the outfan every straight module connects Connect three inputs selecting switch K；

First three the first outfans selecting switch K of end a1 connection of four line standard resistance r1, four The first end a2 of line standard resistance r2 connects three the second outfans selecting switch K, four lines to be measured The first end a3 of fixture electrokinetic cell E connects three the 3rd outfans selecting switch K；

The second end b1 of four line standard resistance r1, the second end b2 of four line standard resistance r2, to be measured The second end b3 of four wire holder electrokinetic cell E, one end of reference resistance r0, signal gathering unit Reference input is connected with the reference input of main control unit；

The 3rd end c1 of four line standard resistance r1, the 3rd end c2 of four line standard resistance r2, to be measured The other end of the 3rd end c3 and reference resistance r0 of four wire holder electrokinetic cell E produces with signal simultaneously The earth terminal of unit connects；

The 4th end d1 of four line standard resistance r1, the 4th end d2 of four line standard resistance r2 and to be measured The 4th end d3 of four wire holder electrokinetic cell E connects the measurement input of signal gathering unit；Signal The outfan of collecting unit is connected with the measurement input of main control unit.

A kind of electrokinetic cell internal resistance on-line monitoring system the most according to claim 1, its feature Be: signal generation unit include Precision Wave-Form Generator IC U1, smart power operational amplifier U2, And precision great current operation amplifier U3；Precision Wave-Form Generator IC U1, smart power operation amplifier The power end of device U2 and accurate great current operation amplifier U3 all with the outfan company of power conversion unit Connect；

The outfan of Precision Wave-Form Generator IC U1 connects the input of smart power operational amplifier U2, The outfan of smart power operational amplifier U2 connects with the input of accurate great current operation amplifier U3 Connecing, the outfan of accurate great current operation amplifier U3 forms the outfan of signal generation unit, and It is connected with the input every straight module.

A kind of electrokinetic cell internal resistance on-line monitoring system the most according to claim 1, its feature It is: signal gathering unit includes high-precision meter amplifier U4 and U5, accurate low imbalance high impedance Operational amplifier U6 and U7, balanced modulation demodulator U8 and accurate low imbalance low drifting computing are put Big device U9；High-precision meter amplifier U4 and U5, accurate low imbalance high input impedance operational amplifier U6 With U7, balanced modulation demodulator U8 and the power supply of accurate low imbalance low drifting operating amplifier U9 End is all connected with the outfan of power conversion unit；

The input of high-precision meter amplifier U4 forms the measurement input of signal gathering unit, and Simultaneously with the 4th end d1, the 4th end d2 of four line standard resistance r2 of four line standard resistance r1 and treat The 4th end d3 surveying four wire holder electrokinetic cell E connects；The outfan of high-precision meter amplifier U4 The input of imbalance high input impedance operational amplifier U6 low with precision is connected；Accurate low imbalance high impedance fortune The outfan calculating amplifier U6 connects the measurement input of balanced modulation demodulator U8；

The input of high-precision meter amplifier U5 forms the reference input of signal gathering unit, and It is connected with one end of reference resistance r0；The outfan of high-precision meter amplifier U5 and the low imbalance of precision The input of high input impedance operational amplifier U7 connects；Accurate low imbalance high input impedance operational amplifier U7's Outfan connects the reference input of balanced modulation demodulator U8；

The outfan of balanced modulation demodulator U8 connects accurate low imbalance low drifting operating amplifier U9's Input, the outfan of accurate low imbalance low drifting operating amplifier U9 forms signal gathering unit Outfan, and be connected with the measurement input of main control unit.

A kind of electrokinetic cell internal resistance on-line monitoring system the most according to claim 1, its feature It is: power conversion unit includes DC-DC voltage conversion manostat U10 and U11 and low pressure drop Linear voltage regulator U12；The input of DC-DC voltage conversion manostat U10 is connected with external power source, DC-DC voltage conversion manostat U10 outfan connect signal generation unit, signal gathering unit and The input of DC-DC voltage conversion manostat U11, the output of DC-DC voltage conversion manostat U11 End connects input and main control unit, the low-voltage-drop linear voltage regulator of low-voltage-drop linear voltage regulator U12 The outfan of U12 connects main control unit.