TWI468713B - A method for calculating a capacity of a super capacitor - Google Patents

Description

Method for estimating capacitance capacity of ultracapacitor

The invention relates to a method for estimating the capacity of a capacitor, in particular to a method for estimating the capacity of a capacitor.

The energy of the mobile device is mostly provided by the battery, but the battery must be connected in series to achieve high energy output performance. However, after each battery is shipped, the internal structure and chemical composition often have slight differences, so its characteristics also follow The number of uses varies. In addition, if the batteries are connected in series without proper control, the voltage and capacity unevenness of each battery unit during charging and discharging will occur, for example, during the charging process of multiple series batteries, there may be one of them. The first reaches the full-charge voltage; conversely, one of the batteries may first drop to the discharge cut-off voltage during the discharge process. Therefore, the overall battery energy utilization performance of the prior art is not fully apparent.

In order to solve the above technical problems, there are many prior art related control and equalization methods. The voltage equalization methods are roughly divided into two types: passive type and active type. The passive type equalizing method refers to connecting a resistor at both ends of each battery. In the process of charging and discharging, a battery with a higher voltage can consume its energy on the resistor. This method has the advantages of simple design and low cost, but the efficiency of energy use is limited. The active voltage equalization rule incorporates the energy transfer concept to transfer the energy of the higher voltage battery to the energy storage element by switching the controller switch, and continuously supply the energy in the energy storage element to the lower voltage battery. This voltage equalization method has higher energy conversion efficiency, but both control and design architecture More complicated. In addition, the merits of the voltage equalization efficiency are quite related to the estimation of the supercapacitor charge value. If the charge value can be correctly estimated, the voltage equalization efficiency will be improved.

In order to solve the above technical problems, the inventor has filed an application and obtained the Patent No. I408393 of the Republic of China Announcement "Method and System for Estimating the Battery Residual Capacity" and Announcement No. I405385 "Battery Equalizing Circuit, Battery System and Battery Equalization The method patent can effectively estimate the residual amount of the battery and perform voltage equalization. Among them, the patent No. I408393 "Method and System for Residual Battery Capacity Estimation" provides a method for estimating the residual amount of the battery and its system. Obtain the initial voltage value and discharge time of the battery to be tested, first determine the capacitance of the battery, and then bring the different discharge currents into the polynomial addition current equation to obtain the additive current value of the battery to be tested, and finally the capacitance and The addition current value calculates the residual amount of the battery, which can greatly reduce the error caused by the estimation of the residual voltage directly by taking the battery voltage and current, and can provide the accurate estimation of the residual amount of the battery. In addition, the I405385 No. "Battery equalizing circuit, battery system and battery equalizing method" patent provides a battery voltage equalizing circuit, including (2M + 2) switching elements and M energy storage The switching element and the energy storage element are used to transfer the high-power battery energy to the battery with low power, thereby achieving uniform charging, easy control, no additional voltage detection circuit, and saving circuit design cost. .

In order to enhance the operating efficiency of energy storage equipment and improve the life of energy storage components, in the special case of consuming a large amount of power in a short time, the prior art has proposed to use ultracapacitors in energy storage equipment. The ultracapacitor has ultra-capacitance of high power density, low equivalent series resistance, fast charge and discharge, and instantaneous release of large current in the energy storage device, and the energy required to provide the load moment. Figure 1 is a schematic diagram of the internal structure of the supercapacitor. Referring to Figure 1, a material such as a carbon base, a metal oxide, or a conductive polymer can be used as an electrode and an electrolyte inside the ultracapacitor. The porous interface forms an electric double layer, and the accumulation and drift of positive and negative charges between the dense electric layer and the diffusion layer can be traversed to reach the other plate for charge storage. In short, the structure of the supercapacitor is mainly to form an electric double layer by using an electrode and an electrolyte for energy storage. Save.

Since the ultracapacitor has a large charge storage capacity and a short transient reaction time, proper design and configuration can help improve the endurance and stability of the overall system. However, the prior art research on supercapacitor mainly focuses on the development and performance improvement of the overall system. It does not discuss the relationship between the component voltage, the capacitance value and the stored energy, and does not combine the supercapacitor with the above battery residual amount. Estimation method and battery equalization method.

In order to evaluate the characteristics of supercapacitor, the prior art has proposed mathematical approximation models such as parameter estimation method of embedded fraction, Euler approximation method and equivalent circuit method, among which in the application of actual high power system, it is more commonly used. Circuit model. Figure 2(a) shows a one-order RC equivalent model of supercapacitor, which consists of an equivalent series resistance (ESR) representing the impedance between the internal terminals of the supercapacitor and the electrolyte impedance and a charge and discharge. The fixed capacitance value is composed. The advantage of this model is that it is easier to calculate, but it cannot describe the nonlinear characteristics of the supercapacitor charging interval. In addition, the second (b) graph is a multi-step RC equivalent model of the supercapacitor, which is to change the fixed capacitance value in the first-order RC equivalent model to multi-stage capacitance in parallel, so it is more suitable for describing the capacitance of the super capacitor charging. The variation of the value, but if the model order is too high, it may affect the performance of the simulation analysis.

In view of this, the present application proposes a method for estimating the charge value of the supercapacitor, which not only helps to estimate the amount of stored capacitance of the ultracapacitor, but also improves the operating efficiency of the supercapacitor, and can cooperate with the battery residual amount estimation method and the battery. The pressure method effectively improves battery efficiency.

The main object of the present invention is to provide a method for estimating the capacitance of an ultracapacitor, which can improve the estimation accuracy of the capacitance or the amount of charge of the supercapacitor.

A second object of the present invention is to provide a method for estimating the capacitance of an ultracapacitor, which can improve the performance of estimating the capacitance or the amount of charge of the supercapacitor.

A further object of the present invention is to provide a capacitor capacity estimation method for an ultracapacitor. The method is simple but can have high estimation accuracy.

Another object of the present invention is to provide a capacitor capacity estimation method for an ultracapacitor. The method is characterized by providing a nonlinear supercapacitor equivalent, which not only can effectively describe the charging process of the supercapacitor, but also effectively simulate the discharge behavior of the supercapacitor.

Another object of the present invention is to provide a method for estimating the capacitance capability of a supercapacitor, which is characterized in that an estimation method of a step function is provided, and after storing the average capacitance value of different voltage intervals, the energy stored by the supercapacitor is further estimated.

Another object of the present invention is to provide a method for estimating the capacitance capability of an ultracapacitor, which is to correct a voltage drop caused by a super capacitor equivalent series resistance when charging and discharging, and causing a voltage drop when discharging. Improve the accuracy of the energy stored inside the ultracapacitor.

In order to achieve the foregoing object, the technical means and the achievable effects of the present invention include: a method for estimating a capacitance capability of an ultracapacitor, which is executed by a processor, and includes: setting a first interval The value (M) is divided into a plurality of first voltage intervals (V ₁ ~V _M ) according to the first interval value (M); according to C = C _M × [ u ( V - V _{M -1} ) - u ( V - V _M )], the capacitance value estimation result in the capacitance capability is obtained; wherein C is the capacitance value estimation result, C _M is the average capacitance value of each first voltage interval, and u (‧) is a step function V is the rated voltage or measured voltage of the super capacitor, and V _M is the boundary value of each first voltage interval. The above capacitive capabilities may include capacitance values or charge values.

In the embodiment of the present invention, the method for estimating the capacitance value of the supercapacitor further includes obtaining an estimation result of the amount of charge (Q) in the capacitance capability according to the estimation result (C) of the capacitance value. Therefore, in this embodiment, the capacitance value estimation result can be obtained first, and then the charge amount estimation result is obtained.

In the embodiment of the present invention, the supercapacitor charge value estimating method, wherein the charge amount (Q) estimation result is obtained according to Q = C × ΔV = C × ( V _initial - V _final ), wherein Q is the electric charge As a result of the estimation, V _{initial is} the initial set voltage of the supercapacitor, and V _{final is} the voltage after the discharge of the supercapacitor is stabilized.

In an embodiment of the present invention, the method for estimating a capacitance capability of the supercapacitor further includes: setting a second interval value (N), and according to the second interval value (N), each first voltage interval (V ₁ ~) V _M ), further divided into a plurality of second voltage intervals (V _M,N ), respectively calculating the capacitance value (C _M,i ) of each second voltage interval and the average value of the capacitance values of the second voltage intervals (C _{M, Avg} ).

In an embodiment of the present invention, the method for estimating a capacitance capability of the supercapacitor further includes: respectively determining a capacitance value (C _M,i ) of each second voltage interval, and a capacitance value of a portion of the second voltage interval (C _{M, i} ) Delete, calculate the average value of the capacitance values (C _M,i ) of the remaining second voltage intervals after the deletion, that is, the average capacitance value (C _M ) of each first voltage interval.

In an embodiment of the present invention, the method for estimating a capacitance capability of the supercapacitor, wherein the determining comprises: setting a maximum error (E), comparing a capacitance value (C _M,i ) of each second voltage interval with each second The average value of the capacitance value of the voltage interval (C _{M, avg} ), if the difference between the capacitance value (C _M,i ) of the second voltage interval and the average value of the capacitance values of the second voltage interval (C _M,avg ) exceeds the The maximum error (E) removes the capacitance value (C _M,i ) of the second voltage interval of the pen.

In an embodiment of the present invention, the method for estimating a capacitance capability of the supercapacitor, wherein the determining comprises: inspecting a capacitance value (C _M,i ) of each second voltage interval of each pen, and if it is an unreasonable negative value, deleting the The capacitance value of the second voltage interval of the pen (C _M,i ).

In an embodiment of the present invention, the method for estimating a capacitance capability of the supercapacitor, wherein the determining comprises: setting a standard deviation value (Z), and calculating a standard deviation of a capacitance value (C _M,i ) of each second voltage interval. (STD), taking the capacitance value (C _M,i ) of each second voltage interval within the standard deviation (STD) of the standard deviation value (Z), and taking the capacitance values of the remaining second voltage intervals (C _{M, i} ) delete.

In the embodiment of the present invention, the first interval value (M) is a positive integer less than 10; the second interval value (N) is a positive integer less than 100; the standard deviation value (Z) is 2 .

〔this invention〕

M‧‧‧ first interval value

V ₁ ~V _M ‧‧‧First voltage interval (boundary value)

C‧‧‧Capacitance value estimation results

C _M ‧‧‧Average capacitance values for each first voltage interval

u(‧)‧‧‧ step function

V‧‧‧Supercapacitor rated voltage or measuring voltage

N‧‧‧ second interval value

V _M,N ‧‧‧second voltage intervals

C _M,i ‧‧‧The capacitance value of the second voltage range

C _{M, avg} ‧‧‧ the average value of the capacitance values of the second voltage range

E‧‧‧Maximum error

Z‧‧‧ standard deviation value

STD‧‧ ‧ standard deviation

Q‧‧‧Charge

V _initial ‧‧‧ initial setting voltage of super capacitor

V _final ‧‧‧The voltage after the discharge of the supercapacitor is stabilized

Figure 1 is a schematic diagram of the internal structure of the prior art supercapacitor.

Figure 2(a) is a one-order RC equivalent model of the prior art supercapacitor.

Figure 2(b) is a multi-order RC equivalent model of prior art supercapacitors.

Fig. 3 is a diagram showing the supercapacitor charge and discharge waveforms of the embodiment of the present invention.

Fig. 4 is a graph showing a capacitance-voltage curve during charging and discharging of an ultracapacitor according to an embodiment of the present invention.

Fig. 5 is a graph showing the capacitance-voltage curve of the supercapacitor at different charging currents according to an embodiment of the present invention.

Fig. 6 is a flow chart showing a method for estimating the charge value of the supercapacitor according to the embodiment of the present invention.

Figure 7 is a comparison of capacitance-voltage curves of an embodiment of the present invention compared to actual measurement results.

Figure 8 is a flow chart of data screening in accordance with an embodiment of the present invention.

FIG. 9 is a flow chart of data screening according to an embodiment of the present invention, and particularly illustrates a screening method selected.

Figure 10 is a flow chart of a method in accordance with still another embodiment of the present invention.

Fig. 11(a) is a diagram showing the normal value of the capacitance value of the ultracapacitor of N = 10 in the embodiment of the present invention.

Figure 11(b) is a diagram showing the normal value of the capacitance value of the ultracapacitor of N = 50 in the embodiment of the present invention.

Figure 11(c) is a diagram showing the normal value of the capacitance value of the ultracapacitor of the embodiment N = 100 in the embodiment of the present invention.

Figure 11(d) is a diagram showing the normal value of the capacitance value of the ultracapacitor of N = 300 in the embodiment of the present invention.

Figure 11(e) is a diagram showing the normal value of the capacitance value of the ultracapacitor of N = 500 in the embodiment of the present invention.

Figure 11(f) is a diagram showing the normal value of the capacitance value of the ultracapacitor of N = 1000 in the embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

Fig. 3 is a diagram showing the waveform of the supercapacitor charge and discharge according to the embodiment of the present invention, using a constant current test method. Please refer to Figure 3, charge the supercapacitor with a fixed current, and charge the supercapacitor to the highest withstand voltage, which is the interval from t1 to t2 in the figure, and the supercapacitance in the interval t2 to t3 After standing for a few minutes, the voltage of the ultracapacitor is stable, and then enter the discharge interval of t3 to t4. In this embodiment, the supercapacitor is discharged at a constant current in this discharge interval until the supercapacitor discharge ends. In addition, in the end of the determination of the supercapacitor discharge, such as the t4 period, at this time due to the chemical reaction inside the supercapacitor, the supercapacitor voltage will rise. In short, this embodiment uses a constant current charging method for testing, and by measuring the differential pressure change of the supercapacitor terminal voltage, the equivalent series resistance of the supercapacitor charging and discharging is obtained, and at the same time, the voltage variation data is obtained. In order to evaluate the capacitance value of the supercapacitor charge and discharge.

Fig. 4 is a graph showing a capacitance-voltage curve during charging and discharging of an ultracapacitor according to an embodiment of the present invention. Please refer to Figure 4, the capacitance value of the supercapacitor during charging is related to the voltage, and the capacitance value of the supercapacitor discharge has no obvious relationship with the voltage. Therefore, if the first-order RC model is used to simulate the overall charge and discharge process of the supercapacitor, It is difficult to describe the change in capacitance value when the supercapacitor is charged. If the charging process is described by a multi-stage RC model, it is possible to extend the simulation time and reduce the overall simulation efficiency. Therefore, the nonlinear supercapacitor equivalent model provided by the embodiment can not only effectively describe the charging process of the ultracapacitor, but also effectively simulate the discharge behavior of the supercapacitor.

In addition, because the prior art method of estimating the amount of supercapacitance charge is to use the supercapacitor terminal voltage data for capacitance value calculation, that is, using the relationship between the supercapacitance voltage and the capacitance value, the capacitance value of the supercapacitor is estimated. However, the instantaneous capacitance value estimated by the prior art method is difficult to estimate during the fluctuation of the supercapacitor voltage. Therefore, in the case of constant voltage change during charging and discharging, it is difficult to estimate the stored energy.

Fig. 5 is a graph showing the capacitance-voltage curve of the supercapacitor at different charging currents according to an embodiment of the present invention. Please refer to Figure 5, because the capacitance value of the supercapacitor is easily affected by the charging current. Therefore, if the supercapacitor is charged with different charging currents, the charge value of the supercapacitor will be estimated. Therefore, in this embodiment, by providing an estimation method of the step function, the average capacitance value of different voltage intervals is counted, and then the energy stored by the super capacitor is further estimated. In addition, this embodiment also corrects that when the supercapacitor is charged and discharged, the super capacitor equivalent series resistance will cause a voltage rise when charging. And the voltage difference caused by the voltage drop during discharge increases the accuracy of the evaluation of the energy stored inside the ultracapacitor.

In this embodiment, a nonlinear equivalent circuit model is used to represent a resistor and a variable capacitor in series as an ultracapacitor equivalent circuit, where C is a varying capacitance value and ESR is an equivalent series resistance. More preferably, the present embodiment performs a mathematical derivation and process establishment of the charge value estimation in a linear step function manner.

Fig. 6 is a flow chart showing a method for estimating the capacitance value of the ultracapacitor according to the embodiment of the present invention. Referring to FIG. 6, the embodiment of the present invention includes the following steps, and the following steps are performed by a processor: (10) setting a first interval value (M), according to the first interval value (M), The supercapacitor voltage is divided into a plurality of first voltage intervals (V ₁ ~V _M ); in this embodiment, the supercapacitor voltage can be obtained according to the rated voltage of the super capacitor, or can be determined according to the actual measured value, for example, The interval of t1 to t2 in Fig. 3; the first interval value (M) can be set according to the required accuracy, for example, M=10 or M=5; in addition, the processor can be centrally processed by a general personal computer. Unit (CPU) or embedded processor (such as ARM); set the first interval value (M) can be retrieved from a database through the CPU, or set by the user; (20) according to C = C _M × [ u ( V - V _{M -1} )- u ( V - V _M )], the capacitance value estimation result is obtained, where C is the capacitance value estimation result, C _M is the average capacitance value of each first voltage interval, u (‧ ) is a step function, V is the rated voltage or measured voltage of the supercapacitor, and V _M is the boundary value of each voltage interval.

Figure 7 is a comparison of capacitance-voltage curves of an embodiment of the present invention compared to actual measurement results. Referring to the figures 6 to 7 at the same time, first, a first interval value (M) is set, and the supercapacitor voltage is divided into a plurality of first voltage intervals (V ₁ to V _M ). For example, the first interval value M=5 is set, and the rated voltage value V of the supercapacitor string is subdivided into several first voltage intervals (V ₁ ~V ₅ ) by means of V/M (ie, V/ ₅ ). As the basis for calculating the average capacitance value of each interval. That is, the capacitance value estimation result C = C ₁ × [ u ( V - V ₀ ) - u ( V - V ₁ )] + C ₂ × [ u ( V - V ₁ ) - u ( V - V ₂ )] +. .. C ₅ ×[ u ( V - V ₄ )- u ( V - V ₅ )], where u(‧) is a step function, V is the rated voltage of the supercapacitor, and C ₁ -C ₅ represents the voltage The average capacitance value after the interval calculation, V ₁ ~ V ₅ is the boundary value of each first voltage interval.

After obtaining the average capacitance value of each voltage interval, the charge amount Q = C × ΔV = C × ( V _initial - V _final ), where V _initial is the initial set voltage of the super capacitor, and V _final is the discharge stability of the super capacitor. After the voltage.

FIG. 8 is a flow chart showing the data filtering method for estimating the capacitance value of the ultracapacitor according to the embodiment of the present invention. Referring to Figure 8, in order to obtain a better estimate, for example, after step (10), a first interval value (M) is set, and the supercapacitor voltage is divided into numbers according to the first interval value (M). After the first voltage interval (V ₁ ~V _M ), steps (11) to (15) are performed, wherein steps (12) to (14) may be used alternatively or in combination, and the order is not limited. Specifically, the method for estimating the capacitance value of the supercapacitor according to the embodiment of the present invention further includes: respectively determining a capacitance value (C _M,i ) of each second voltage interval, and a capacitance value of a portion of the second voltage interval (C _M,i Delete, calculate the average value of the capacitance values (C _M,i ) of the remaining second voltage intervals after the deletion, which is the average capacitance value (C _M ) of each first voltage interval. For example, the data screening in this embodiment may include: (11) setting a second interval value (N), and dividing each of the divided first voltage intervals (V ₁ ~V according to the second interval value (N) _M , for example, select V _M ), and then divide into a plurality of second voltage intervals (V _M,i , where i=1~N), respectively calculate the capacitance values (C _M,i ) of each second voltage interval and each second The average value of the capacitance value of the voltage interval (C _{M, avg} ); (12) setting a maximum error (E), comparing the capacitance value of the second voltage interval (C _M,i ) and the capacitance of each second voltage interval The value average (C _{M, avg} ), if the difference between the capacitance value (C _M,i ) of the second voltage interval and the average value of the capacitance values of the second voltage interval (C _M,avg ) exceeds the maximum error (E ), the capacitance value (C _M,i ) of the second voltage interval of the pen is deleted; (13) the capacitance value (C _M,i ) of the second voltage interval of each pen is examined, and if it is an unreasonable negative value, the deletion is performed. The capacitance value of the second voltage interval (C _M,i ); (14) setting a standard deviation value (Z), and calculating the standard deviation (STD) of the capacitance value (C _M,i ) of each second voltage interval , taking the positive and negative of the standard deviation value (Z) within the standard deviation (STD) Voltage interval of the second capacitance value (C _{M, i),} and the capacitance value of each of the remaining strokes of the second voltage interval (C _{M, i)} deleted; the standard deviation value (Z) may be for example 2; (15) calculated The average value of the capacitance values (C _M,i ) of the remaining second voltage intervals is the average capacitance value (C _M ) of each first voltage interval; and then according to step (20), according to C = C _M ×[ u ( V - V _{M -1} )- u ( V - V _M )], the capacitance value is obtained, and then the charge amount can be estimated, where C is the capacitance value estimation result, and C _M is the average capacitance value of each first voltage interval. u(‧) is the step function, V is the rated voltage or measured voltage of the supercapacitor, and V _M is the boundary value of each voltage interval.

FIG. 9 is a schematic diagram of the data screening process of the embodiment, which illustrates an optional implementation process. Please also refer to the figures 8 to 9, wherein the second interval value N divides each of the first voltage intervals V ₁ VV _M , for example, V _M , into several second voltage intervals V _M,i , where i= 1~N, and C _M,avg is the average value of the capacitance values C _M,i of the N second voltage intervals, and the maximum error E is the set maximum error. In this embodiment, the value is set to C _{M ,} 2 times _avg , if the difference between C _M,i and C _M,avg exceeds the maximum error E, or C _M,i is an unreasonable negative value, such as a negative value, the data will be considered invalid and deleted. . Then, the standard deviation STD of the remaining data can be recalculated, and at the same time, the data of the positive and negative Z (standard deviation value) standard deviations are taken by the concept of the normal distribution, and the remaining values are deleted, and the average value of the selected values is continuously calculated. The average capacitance value of each voltage interval can be obtained. In this embodiment, the standard deviation value Z can be set to 2, that is, about 95% of the data within 2 standard deviations is selected. This step can better consider the acquisition of the error data, reduce the error estimation caused by the amount of charge of the supercapacitor, and improve the accuracy of the evaluation of the capacitance of the supercapacitor to more accurately evaluate the average capacitance value of each voltage interval.

Figure 10 is a flow chart showing a method of determining a charge amount estimation result according to still another embodiment of the present invention. Referring to FIG. 10, in order to obtain the charge amount estimation result according to the use requirement, the embodiment includes: setting a first interval value (M), and dividing the super capacitor voltage according to the first interval value (M). a plurality of first voltage intervals (V ₁ ~V _M ); setting a second interval value (N), and dividing each of the first voltage intervals (V ₁ ~V _M ) according to the second interval value (N) Calculating a capacitance value (C _M,i ) of each second voltage interval and a capacitance value average value (C _M,avg ) of each second voltage interval for a plurality of second voltage intervals (V _M,N ); the capacitance value of the second voltage interval (C _{M, i),} the portion of the second segment of the voltage value of the capacitance (C _{M, i)} delete, remove the calculated value of the remaining capacitance (C _{M, i)} a second voltage interval of each pen The average value is the average capacitance value (C _M ) of each first voltage interval: the capacitance value estimation result in the capacitance capability is obtained; and the charge amount (Q) estimation result in the capacitance capability is obtained. The method of deleting the capacitance value of the second voltage section, the method of estimating the capacitance value, or the method of estimating the charge amount has been described above, and will not be described herein.

Since the present embodiment uses the step function method to simulate the voltage response of the supercapacitor to analyze the influence of each voltage interval on the capacitance value estimation, each voltage interval (V ₁ ~V _M ) can be subdivided into N voltage segments ( V _M,i , where i=1~N), averages the capacitance values obtained by the N segments to investigate the relationship between the supercapacitor voltage and the capacitance value. Table 1 and Table 2 are the relationship between the supercapacitor voltage and the capacitance value obtained by testing different supercapacitor modules respectively. Table 1 is a comparison table of the capacitance values of the voltage ranges of a single supercapacitor in parallel, and Table 2 is two strings and two The comparison of the capacitance values of the voltage ranges; wherein the test module used in Table 1 is a single 200F supercapacitor connected in parallel to 400F, and in Table 2, the ultra-capacitor with a withstand voltage of 2.7V is used as two strings to improve The withstand voltage of the ultracapacitor module.

The 11th (a) to 9th (f) diagram is a normal state distribution diagram of the capacitance of the ultracapacitor of the present embodiment N=10~1000. From the normal distribution maps in Figures 11(a) to 9(f), it can be seen that when the cutting interval N is larger in each voltage interval, the estimated average capacitance value will be susceptible to voltage changes; otherwise, if N value The smaller the value, the lesser the voltage is slightly less likely to change significantly when estimating the average capacitance value, so the estimated average capacitance value is more stable. This embodiment suggests that the value of N can be within 100.

Because supercapacitors are used in practical applications, they are generally used to assist energy storage devices to provide energy to the load. Therefore, the advantages and disadvantages of supercapacitor energy storage capacity will affect the work efficiency. In this embodiment, a nonlinear equivalent circuit is used as a model of the supercapacitor, and the step function method is used to estimate the capacitance value of each voltage interval, thereby assisting in estimating the amount of charge of the supercapacitor in each voltage interval, which not only helps the future engineering personnel. Master the operating characteristics of the ultracapacitor while monitoring the energy currently available for the supercapacitor.

In order to prove that the method of the present embodiment can estimate the available energy of the supercapacitor at various voltage levels, the test uses the power supply to charge the ultracapacitor module to the initial set voltage V _initial of the supercapacitor, and then rests for several minutes. When the voltage of the ultracapacitor tends to be stable, the energy of the ultracapacitor is extracted by the electronic load until the supercapacitor voltage drops to 0.01V, the discharge is stopped, and when the voltage of the supercapacitor tends to be stable, the supercapacitor is recorded again. After the discharge is stable, the voltage V _final , Table 3 and Table 4 are the charge estimation results of the single supercapacitor parallel module and the two strings of two parallel modules working at different voltage levels; Table 3 is a single supercapacitor in parallel The module works at different voltage levels to estimate the amount of charge. Table 4 shows the results of the two-string two-capacitor module operating at different voltage levels. Wherein the super capacitor prompted by internal chemical reaction, resulting in slightly different values of V _final. It can be seen from Table 3 and Table 4 that the error of the charge amount estimation and the measured value using the method of the present embodiment are both within 5%.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

Claims (16)

A method for estimating a capacitance capability of a supercapacitor is performed by a processor, comprising: setting a first interval value (M), and dividing the supercapacitor voltage into a plurality of first voltage intervals according to the first interval value (M) ( V ₁ ~V _M ); and according to C = C _M ×[ u ( V - V _{M -1} )- u ( V - V _M )], the capacitance value estimation result in the capacitance capability is obtained, where C is the capacitance value The estimation result, C _M is the average capacitance value of each first voltage interval, u (‧) is a step function, V is the rated voltage or measurement voltage of the super capacitor, and V _M is the boundary value of the first voltage interval. The method for estimating the capacitance capability of the supercapacitor according to claim 1 of the patent application, further comprising: obtaining the charge amount (Q) estimation result in the capacitance capability according to the capacitance value estimation result (C). The method for estimating a capacitance capability of an ultracapacitor according to claim 2, wherein the charge amount (Q) estimation result is obtained according to Q = C × ΔV = C × ( V _initial - V _final ), wherein Q For the estimation of the charge amount, V _{initial is} the initial set voltage of the super capacitor, and V _{final is} the voltage after the discharge of the super capacitor is stabilized. The method for estimating the capacitance capability of the ultracapacitor according to any one of claims 1 to 3, further comprising: setting a second interval value (N), and each of the first voltages according to the second interval value (N) The interval (V ₁ ~V _M ) is further divided into a plurality of second voltage intervals (V _M,N ), and the capacitance values (C _M,i ) of the second voltage sections and the capacitance values of the second voltage sections are respectively calculated. Value (C _{M, avg} ). The method for estimating the capacitance capability of the supercapacitor according to item 4 of the patent application scope further comprises: respectively determining a capacitance value (C _{M, i} ) of each second voltage interval, and a capacitance value of a part of the second voltage interval (C _{M , i} ) delete, calculate the average value of the capacitance values (C _M,i ) of the remaining second voltage intervals after the deletion is the average capacitance value (C _M ) of each first voltage interval. The method for estimating the capacitance capability of the ultracapacitor according to claim 5, wherein the determining comprises: setting a maximum error (E), comparing capacitance values (C _{M, i} ) of each second voltage interval and each The average value of the capacitance value of the second voltage interval (C _M,avg ), if the capacitance value of the second voltage interval (C _M,i ) is different from the average value of the capacitance values of the second voltage interval (C _M,avg ) When the maximum error (E) is exceeded, the capacitance value (C _M,i ) of the second voltage interval of the pen is deleted. The method for estimating the capacitance capability of the ultracapacitor according to claim 5, wherein the determining comprises: examining a capacitance value (C _M,i ) of each second voltage interval, and if it is an unreasonable negative value, The capacitance value (C _M,i ) of the second voltage interval of the pen is deleted. The method for estimating the capacitance capability of the supercapacitor according to claim 6, wherein the determining comprises: checking a capacitance value (C _M,i ) of each second voltage interval, and if it is an unreasonable negative value, The capacitance value (C _M,i ) of the second voltage interval of the pen is deleted. The method for estimating the capacitance capability of the ultracapacitor according to claim 5, wherein the determining comprises: setting a standard deviation value (Z), and calculating a capacitance value (C _{M, i} ) of each second voltage interval. Standard deviation (STD), taking the capacitance value (C _M,i ) of each second voltage interval within the standard deviation (STD) of the standard deviation value (Z), and the capacitance value of the remaining second voltage intervals (C _M,i ) Delete. The method for estimating the capacitance capability of the supercapacitor according to claim 6, wherein the determining comprises: setting a standard deviation value (Z), and calculating a capacitance value (C _{M, i} ) of each second voltage interval. Standard deviation (STD), taking the capacitance value (C _M,i ) of each second voltage interval within the standard deviation (STD) of the standard deviation value (Z), and the capacitance value of the remaining second voltage intervals (C _M,i ) Delete. The method for estimating the capacitance capability of the ultracapacitor according to claim 7, wherein the determining comprises: setting a standard deviation value (Z), and calculating a capacitance value (C _{M, i} ) of each second voltage interval. Standard deviation (STD), taking the capacitance value (C _M,i ) of each second voltage interval within the standard deviation (STD) of the standard deviation value (Z), and the capacitance value of the remaining second voltage intervals (C _M,i ) Delete. The method for estimating the capacitance capability of the supercapacitor according to claim 8 , wherein the determining comprises: setting a standard deviation value (Z), and calculating a capacitance value (C _{M, i} ) of each second voltage interval. Standard deviation (STD), taking the capacitance value (C _M,i ) of each second voltage interval within the standard deviation (STD) of the standard deviation value (Z), and the capacitance value of the remaining second voltage intervals (C _M,i ) Delete. The method for estimating the capacitance capability of the ultracapacitor according to claim 7, wherein the determining comprises: setting a standard deviation value (Z), and calculating a capacitance value (C _{M, i} ) of each second voltage interval. Standard deviation (STD), taking the capacitance value (C _M,i ) of each second voltage interval within the standard deviation (STD) of the standard deviation value (Z), and the capacitance value of the remaining second voltage intervals (C _M,i ) Delete. The method for estimating a capacitance capability of an ultracapacitor according to any one of claims 1 to 3, wherein the first interval value (M) is a positive integer less than 10. The method for estimating the capacitance capability of the ultracapacitor according to claim 4, wherein the second interval value (N) is a positive integer less than 100. The method for estimating the capacitance capability of the ultracapacitor according to claim 9 of the patent application, wherein the standard deviation value (Z) is 2.