CN110554328A - HHT-based storage battery internal resistance measuring method and system - Google Patents
HHT-based storage battery internal resistance measuring method and system Download PDFInfo
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- 238000002347 injection Methods 0.000 claims description 11
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/389—Measuring internal impedance, internal conductance or related variables
Abstract
A method and a system for measuring the internal resistance of a storage battery based on HHT comprise S1, injecting sinusoidal alternating current signals into a main loop formed by the storage battery and a sampling resistor, collecting characteristic voltage signals U 1 and U 2 of the storage battery and the sampling resistor, S2, obtaining effective values U 1rms and U 2rms of the voltage signals of the storage battery and the sampling resistor by HHT of the characteristic voltage signals U 1 and U 2, and S3, calculating the internal resistance of the storage battery by ohm law according to the resistance value of the sampling resistor, U 1rms and U 2rms.
Description
Technical Field
the invention relates to the field of storage battery internal resistance measuring methods, in particular to a storage battery internal resistance measuring method and system based on HHT.
background
the storage battery is an important energy storage device and has the advantages of convenience in use, excellent performance, stable voltage, safety, reliability and the like. With the development of national economy, storage batteries are used in some traditional fields: power generation, navigation, aviation, military industry and the like, and is also applied to some new energy fields: electric vehicles, renewable energy sources, new materials, equipment manufacturing and the like, and the wide application range puts higher requirements on the performance of the storage battery. Through the development of the storage battery in the last 160 years, the technology is gradually mature, but still some problems still exist, such as low energy density, short service life, untimely fault early warning and the like, which slightly affect the daily use of the storage battery, and seriously cause power failure, fire disaster, equipment burnout and great economic loss. On the premise that the technical difficulties are not broken through, a method capable of effectively managing and monitoring the storage battery is urgently needed to be found.
research shows that the scrapping, insufficient capacity or wrong charging and discharging of the storage battery can be reflected by the change of the internal resistance of the storage battery, so that the change of the internal state of the storage battery can be known by detecting the internal resistance of the storage battery. At present, common methods for measuring the internal resistance of the storage battery comprise: density methods, open circuit voltage methods, direct current discharge methods, and alternating current injection methods. The density method calculates the internal resistance of the battery by the density of the electrolyte of the battery, and is therefore suitable for open type lead-acid batteries but not for sealed lead-acid batteries. The open-circuit voltage method is to measure the voltage at two ends of the accumulator and then calculate its internal resistance. In general, the error of the calculation result is large, and sometimes an incorrect result is obtained. The direct current discharge method is to discharge the load resistance by the storage battery in a short time with large current, measure the instantaneous voltage drop at two ends of the storage battery, and calculate the internal resistance through ohm's law. The measuring method has simple conditions, simultaneously is accompanied with large current, and has stronger anti-interference capability of measuring signals, but when the storage battery discharges for a short time, the current can reach dozens or even hundreds of amperes, and the large current can cause certain damage to the inside of the storage battery, so that the same storage battery is inconvenient to be measured for many times. In addition, the method can only carry out off-line measurement, otherwise, potential safety hazards can be caused to the system.
the ac injection method is a common method at present. The principle is that an alternating current signal with constant frequency and small amplitude is injected into a storage battery, the current passing through the storage battery and the voltage response of two ends of the storage battery are measured, and then the internal resistance of the storage battery is calculated through ohm's law. The method can ensure that the measuring system does not influence the working state and the safety of the storage battery and the application system thereof, but the required measuring circuit is more complex, and the measuring signal is smaller and is often submerged in noise interference. Meanwhile, the measured internal resistance of the storage battery is different due to different frequencies of the alternating current signals. Therefore, if this method is adopted, a solution needs to be designed for these several problems.
Disclosure of Invention
the invention mainly aims to overcome the defects in the prior art, and provides a method and a system for measuring the internal resistance of a storage battery based on HHT, which can solve the problem of inaccuracy of measurement of the internal resistance of the storage battery caused by the existence of interference signals in the prior art.
the invention adopts the following technical scheme:
A HHT-based storage battery internal resistance measuring method is characterized by comprising the following steps:
s1, injecting a sine alternating current signal into a main loop consisting of the storage battery and the sampling resistor, and collecting characteristic voltage signals U 1 and U 2 of the storage battery and the sampling resistor;
S2, obtaining voltage signal effective values U 1rms and U 2rms of the storage battery and the sampling resistor respectively for the characteristic voltage signals U 1 and U 2 through HHT;
and S3, calculating the internal resistance of the storage battery through ohm law according to the resistance value of the sampling resistor, U 1rms and U 2rms.
Preferably, the S2 specifically includes the following steps:
s21, EEMD decomposition is respectively carried out on the characteristic voltage signals U 1 and U 2 to obtain IMF components without mode aliasing;
S22: respectively carrying out Hilbert transform on the two groups of IMF components to obtain instantaneous frequency and instantaneous amplitude;
and S23, obtaining effective values U 1rms and U 2rms according to the frequency of the sinusoidal alternating current signal injected into the main loop and the instantaneous frequency obtained by the Hilbert conversion.
preferably, the storage battery internal resistance calculation formula is as follows:
wherein: and r is the resistance value of the sampling resistor.
The utility model provides a battery internal resistance measurement system based on HHT which characterized in that includes:
The main circuit module is provided with a storage battery, a sampling resistor, a load and a switch which form a loop;
The sine alternating current signal injection module is used for injecting a sine alternating current signal into the main circuit module;
the measuring module is used for acquiring characteristic voltage signals U 1 and U 2 of the storage battery and the sampling resistor;
The storage battery internal resistance calculation device comprises a main control module and a storage battery internal resistance calculation module, wherein the main control module is provided with a voltage signal effective value calculation module used for obtaining voltage signal effective values U 1rms and U 2rms of characteristic voltage signals U 1 and U 2 through HHT, and the storage battery internal resistance calculation module used for obtaining storage battery internal resistance through ohm's law calculation according to sampling resistance values r, U 1rms and U 2rms.
preferably, the sinusoidal ac signal injection module further includes:
the sine function generating module is used for generating a sine alternating current signal;
A drive circuit for converting a sinusoidal alternating current signal into a current;
And the constant current power amplifier is used for stably outputting current.
as can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:
According to the invention, the EEMD is used for decomposing the characteristic voltage signal to obtain an IMF component, and then the Hilbert transform is used for the IMF component to obtain the instantaneous frequency and the instantaneous amplitude to obtain the effective value of the voltage signal, so that the measured internal resistance of the storage battery can obtain an accurate measured value.
Drawings
FIG. 1 is a block diagram of a HHT-based battery internal resistance measurement system provided by the present invention;
FIG. 2 is a circuit diagram of a main circuit module according to the present invention;
FIG. 3 is a schematic diagram of a sinusoidal AC signal injection module provided by the present invention;
FIG. 4 is a circuit diagram of a sine function generation module;
FIG. 5 is a circuit diagram of a driving circuit and a constant current power amplifier module;
FIG. 6 is a flow chart of a method of the present invention;
fig. 7 is a flowchart of step S2;
FIG. 8 is a flow chart of the EEMD decomposition calculation;
The invention is described in further detail below with reference to the figures and specific examples.
Detailed Description
the invention is further described below by means of specific embodiments.
the invention provides a method for measuring the internal resistance of a storage battery based on HHT, which is shown in figure 6 and comprises the following steps:
and S1, injecting a sinusoidal alternating current signal into a main loop formed by the storage battery and the sampling resistor, and collecting characteristic voltage signals U 1 and U 2 of the storage battery and the sampling resistor.
for example: the sinusoidal alternating current signal is sinusoidal current with the amplitude of 100mA and the frequency of 1kHz, and a DC component in the measurement signal is filtered out by using a DC blocking capacitor. It is known from the sampling theorem that the sampling frequency needs to be 2 times higher than the highest frequency in the signal, so that the information in the original signal is not lost after sampling, and considering that the sampling frequency has a great influence on the EEMD decomposition, for high-precision signal recovery, the sampling frequency needs to be even 8 times higher than the highest frequency in the signal. Preferably, a frequency of 100kHz is used.
S2, referring to FIG. 7, obtaining effective voltage signal values U 1rms and U 2rms of the storage battery and the sampling resistor by HHT of the characteristic voltage signals U 1 and U 2 respectively, and the method specifically comprises the following steps:
s21, EEMD decomposition is respectively carried out on the characteristic voltage signals U 1 and U 2 to obtain respective IMF components without modal aliasing, as shown in FIG. 8, the EEMD decomposition step comprises:
suppose that:
The signal has at least one maximum point and one minimum point;
The characteristic time scale is defined by the time lapse between extreme points;
If the signal contains only the inflection point and not the extreme point, the extreme point may be obtained by differentiating once or more times, and then the obtained components may be integrated.
the standard deviation of white noise N (t) is set to be N std times of the standard deviation of the original signal x (t) and the overall average times are set to be N, the values of N std and N are respectively 0.7 and 100, and t represents time.
adding white noise n i (t) to the original signal to obtain a new set of mixed signals:
Xi(t)＝x(t)+ni(t) i＝1,2,…,N。
performing EMD decomposition on the mixed signals respectively to obtain:
In the formula (1), m is the number of IMFs obtained after each EMD decomposition, and c i (t) and r i (t) are the IMF component and the residual component, respectively.
performing a global average operation on the IMF obtained by the formula (1):
in equation (2), c i (t) is the i-th IMF component obtained by EEMD decomposition, and r (t) is the remaining component, the final EEMD decomposition result is:
S22: and respectively carrying out Hilbert transform on the two groups of IMF components to obtain instantaneous frequency and instantaneous amplitude, wherein the Hilbert transform step comprises the following steps of:
Performing a hilbert transform on each IMF, one can obtain:
And further obtaining an analytic signal:
The instantaneous amplitude and phase are:
The instantaneous angular frequency and instantaneous frequency are:
thus, the hubert time spectrum can be expressed as:
it should be noted that the residual component r i (t) is a monotonic function or a constant, representing the trend of the original signal, and is therefore ignored when computing the Hilbert spectrum.
And S23, obtaining effective values U 1rms and U 2rms according to the frequency of the sinusoidal alternating current signal injected into the main loop and the instantaneous frequency obtained by the Hilbert conversion.
and S3, calculating the internal resistance of the storage battery according to the resistance values r, U 1rms and U 2rms of the sampling resistors through ohm' S law.
the calculation formula of the ohm law is as follows:
in the formula (3), R, I rms is divided into effective values of the current signal flowing through the storage battery due to the internal resistance of the storage battery.
Because the sampling resistor and the storage battery are in the same main loop, and the alternating currents flowing through the sampling resistor and the storage battery are equal, the sampling resistor and the storage battery can be obtained by ohm's law:
the internal resistance of the storage battery is as follows:
As shown in fig. 1, the invention further provides a HHT-based storage battery internal resistance measurement system, which comprises a main circuit module 10, a sinusoidal alternating current signal injection module 20, a measurement module 30, a PC 40, a communication module 50 and the like. The main circuit module 10 comprises a storage battery GB, a sampling resistor R, a load RL and a switch K, wherein the storage battery GB, the sampling resistor R, the load RL and the switch K form a loop, and the storage battery RL discharges to the load RL by controlling the switch K to be closed.
as shown in fig. 2 to 5, a sinusoidal ac signal injection module for injecting a sinusoidal ac signal into the main circuit module 10. The sinusoidal alternating current signal injection module 20 comprises a sinusoidal function generation module 21, a driving circuit 22 and a constant current power amplifier 21. The SINE function generating module 21 is used to generate a SINE voltage signal with a desired frequency, which can be implemented by a chip with model number ICL8038 and peripheral circuits, as shown in fig. 4, where the SINE pin outputs the SINE voltage signal. The driving circuit 22 is used for converting the voltage output by the sine function generation module 21 into a current. The constant current amplifier 21 is used for stabilizing the output current of the constant current driving module, referring to fig. 5, two TLs 082 and TDA2030 are used to combine with a peripheral circuit to realize the constant current amplifier, and one end of the resistor RV5 in the drawing is used as the output end of the constant current amplifier 21. Preferably, the input of the sinusoidal ac signal injection module 20 is a dc power supply of ± 15V, and the output is a sinusoidal current with an amplitude of 100mA and a frequency of 1 kHz.
the measurement module 30 is configured to detect characteristic voltage signals of the storage battery GB and the sampling resistor R during operation of the main circuit module 10 and send the characteristic voltage signals to the main control module 10. Specifically, two blocking capacitors c are arranged and are respectively connected in series with one end of the sampling resistor R and one end of the storage battery GB, and direct-current components in the measurement signals are filtered through the blocking capacitors c.
The communication module 50 is connected to the measurement module 30, and is configured to send the voltage signal of the measurement module 30 to the main control module 10, so as to convert an analog signal into a digital signal. Specifically, the analog-to-digital conversion (ADC) is performed on the ac voltage component at the two ends of the sampling resistor R and the ac voltage component at the two ends of the storage battery, and then the data is transmitted to the main control module 10 using the Serial Communication Interface (SCI).
the main control module 10 receives the voltage signal sent by the measuring module 30, and calculates the internal resistance of the storage battery by adopting the method for measuring the internal resistance of the storage battery of HHT, and comprises a module for calculating the effective value of the voltage signal and a module for calculating the internal resistance of the storage battery, wherein the module for calculating the effective value of the voltage signal is used for obtaining the effective values of the voltage signal U 1rms and U 2rms for the characteristic voltage signals U 1 and U 2 after HHT, and the module for calculating the internal resistance of the storage battery is used for calculating the internal resistance of the storage battery through ohm law according to the resistance value r of the sampling resistor, U 1rms and U 2rms.
the above description is only an embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by using the design concept should fall within the scope of infringing the present invention.
Claims (5)
1. a HHT-based storage battery internal resistance measuring method is characterized by comprising the following steps:
s1, injecting a sine alternating current signal into a main loop consisting of the storage battery and the sampling resistor, and collecting characteristic voltage signals U 1 and U 2 of the storage battery and the sampling resistor;
s2, obtaining voltage signal effective values U 1rms and U 2rms of the storage battery and the sampling resistor respectively for the characteristic voltage signals U 1 and U 2 through HHT;
And S3, calculating the internal resistance of the storage battery through ohm law according to the resistance value of the sampling resistor, U 1rms and U 2rms.
2. The HHT-based battery internal resistance measurement method of claim 1, wherein the S2 specifically comprises the steps of:
S21, EEMD decomposition is respectively carried out on the characteristic voltage signals U 1 and U 2 to obtain IMF components without mode aliasing;
S22: respectively carrying out Hilbert transform on the two groups of IMF components to obtain instantaneous frequency and instantaneous amplitude;
and S23, obtaining effective values U 1rms and U 2rms according to the frequency of the sinusoidal alternating current signal injected into the main loop and the instantaneous frequency obtained by the Hilbert conversion.
3. The HHT-based battery internal resistance measurement method according to claim 1, wherein the battery internal resistance calculation formula is:
wherein: and r is the resistance value of the sampling resistor.
4. the utility model provides a battery internal resistance measurement system based on HHT which characterized in that includes:
The main circuit module is provided with a storage battery, a sampling resistor, a load and a switch which form a loop;
the sine alternating current signal injection module is used for injecting a sine alternating current signal into the main circuit module;
the measuring module is used for acquiring characteristic voltage signals U 1 and U 2 of the storage battery and the sampling resistor;
The storage battery internal resistance calculation device comprises a main control module and a storage battery internal resistance calculation module, wherein the main control module is provided with a voltage signal effective value calculation module used for obtaining voltage signal effective values U 1rms and U 2rms of characteristic voltage signals U 1 and U 2 through HHT, and the storage battery internal resistance calculation module used for obtaining storage battery internal resistance through ohm's law calculation according to sampling resistance values r, U 1rms and U 2rms.
5. the HHT-based battery internal resistance measurement system of claim 4, wherein the sinusoidal ac signal injection module further comprises:
The sine function generating module is used for generating a sine alternating current signal;
a drive circuit for converting a sinusoidal alternating current signal into a current;
and the constant current power amplifier is used for stably outputting current.
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| CN111257776A (en) * | 2020-03-03 | 2020-06-09 | 珠海朗尔电气有限公司 | Method and device for measuring internal resistance of storage battery |
| CN113533986A (en) * | 2021-07-16 | 2021-10-22 | 厦门爱维达科技工程有限公司 | VMD-Hilbert-based storage battery internal resistance measuring method and system |
| CN116148697A (en) * | 2023-04-04 | 2023-05-23 | 杭州华塑科技股份有限公司 | Battery internal resistance detection method and device for battery pack and storage medium |
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| CN113533986A (en) * | 2021-07-16 | 2021-10-22 | 厦门爱维达科技工程有限公司 | VMD-Hilbert-based storage battery internal resistance measuring method and system |
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