KR20120113613A - Potable charging apparatus using edlc and method of edlc capacity selecting the same - Google Patents

Abstract

PURPOSE: A portable energy charging device using an electric double layer capacitor and a method for selecting the capacity of the electric double layer capacitor are provided to obtain stable charging performance by using the electric double layer capacitor layer instead of a battery to reduce a voltage regulation. CONSTITUTION: An electric double layer capacitor(20) is connected in parallel to a solar cell module(10) and stores energy generated from the solar cell module. A constant voltage protection circuit(25) is connected in parallel to the electric double layer capacitor and protects the electric double layer capacitor against an overvoltage by equalizing the voltage of each electric double layer capacitor. A control device is installed between the solar cell module and the electric double layer capacitor.

Description

Portable energy charging device using supercapacitor and method for selecting supercapacitor capacity of device {POTABLE CHARGING APPARATUS USING EDLC AND METHOD OF EDLC CAPACITY SELECTING THE SAME}

The present invention relates to a portable energy charging device using a supercapacitor and a method of selecting a supercapacitor capacity of the device, and more particularly, to replace a conventional heavy lead capacitor and to use a supercapacitor (EDLC) of an existing energy storage device. The present invention relates to a portable energy charging device using a supercapacitor and a method for selecting a supercapacitor capacity of the device to compensate for the problem and to ensure a stable operation and lifetime of the energy storage device.

BACKGROUND With the development of computers and electronic technologies, various electronic devices and computers that can be carried by individuals are widely used, and various electronic devices are used while carrying them for business or personal use.

Various conventional portable electronic devices of the related art require a constant power source for the operation, and since the battery originally installed in the electronic device has limitations that can only be used for a certain time, the performance of the personal portable electronic device has been improved. Many companies and inventors are devoting themselves to battery development.

However, even if a battery of a portable electronic device with high performance is developed, since it has a certain service life, it is fundamentally difficult to use it for a long time without an external power supply.

Accordingly, a portable energy charging device using a photovoltaic power generation system was developed, and the existing portable energy charging device was marketed to the enthusiast layer in the form of a portable energy bank that has emerged since the emergence of the initial photovoltaic power generation system. Currently, it is mainly used for leisure, and the portable charging device is recently expanded to a very active field of application such as being used in the form of a small charger or a mobile phone.

However, due to the low price competition, the performance is very poor, and the deterioration of the solar cell module degrades the product quality, and the necessity of an energy storage device having high quality differentiated functions and performances has emerged in the market applied for leisure or portable. To this end, various types of battery protection were added, but the weight and cost increase had a negative effect on the actual product.

On the other hand, since solar power generation is not infinite power unlike general power supply, it is difficult to control the charging current, so there is a high possibility of overcharging and overdischarging the battery. In addition, the amount of generation of the solar cell module varies greatly depending on the amount of solar radiation, and even at the same amount of solar radiation, the charging current is significantly different depending on the state of the battery, making it difficult to apply the constant voltage charging or the constant current charging method used for charging the battery to the solar power system.

In addition, in the case of a stand-alone photovoltaic system, when the battery is inadequately charged and discharged, overcharging and discharging occurs in the battery, thereby shortening the battery life.

The present invention was devised to solve the above problems, the object of the present invention is to replace the battery, such as the lead-acid lead-acid battery by using a supercapacitor, the voltage fluctuation rate is lower than the battery can have a stable charging performance, of course The present invention provides a portable energy charging device using a supercapacitor capable of using charged energy.

In addition, the present invention by applying a supercapacitor connected in parallel with the solar cell module to compensate for the instantaneous voltage drop and take charge of the peak power to enable stable operation as well as supercapacitors to ensure long life with more than tens of thousands of charge and discharge performance It is to provide a portable energy charging device using a supercapacitor to increase the charging efficiency of the overall charging device further by using the and to increase the life by protecting the voltage from the over-voltage by equalizing through the zener diode.

In addition, the storage means, such as the battery of the conventional portable energy charging device acts as a factor of weight and volume increase fatal to the portability, the portable energy charger of the present invention is a supercapacitor bank that can minimize the effects of weight and volume By designing an optimized circuit, the energy charger can be used temporarily under sub-injection conditions, and a battery remaining capacity display means is further provided to support the portable energy charger using a supercapacitor that can be supplemented functionally. To provide.

In addition, the present invention selects the optimal size (capacity) of the supercapacitor according to the energy storage time to configure the circuit to be effectively charged so that the supercapacitor of the portable energy charging device to use the stored energy under low insolation or various conditions To provide a capacity selection method.

The portable energy charging device is configured to achieve the above object in the portable energy charging device for temporarily storing the energy generated by the solar cell module in a place without irradiation of light energy and maintaining the energy capacity level. The supercapacitor bank, comprising one or more supercapacitors, is connected to the solar cell module in parallel to store energy generated by the solar cell module.

Here, a constant voltage protection circuit is connected in parallel to the supercapacitor so as to equalize the voltage of each supercapacitor and protect it from overvoltage, and a control device is installed between the solar cell module and the supercapacitor bank to regulate power supply. Preferably, the control device is composed of a MPPT controller of the maximum power output point tracking method for controlling the energy generated through the solar cell module to generate the maximum output at low insolation or various conditions, and a constant voltage control converter installed at a rear end thereof. .

On the other hand, the method of selecting the capacity of the supercapacitor of the energy charging device, in the capacity selection method of the supercapacitor applied to the portable energy charging device to store the energy generated in the solar cell module, the basic parameters of the energy charging device (maximum Determining a minimum voltage, generated power, and energy storage time; Determining an average current value and a voltage variation value of the supercapacitor using the basic parameters; Determining the total capacitance value required by the energy charging device according to the determined average current value and the voltage variation value of the supercapacitor; and selecting the capacity of the supercapacitor.

In this case, when the maximum voltage value of the portable energy charger is Vmax, the minimum voltage value Vmin, and the maximum voltage value Vw of the capacitor, the voltage variation value is dV = Vw−Vmin as a voltage drop due to the discharge of the supercapacitor. , The total capacitance value C is formed by

Here, i is an average current value flowing through the energy charging device, dV is a voltage variation value of the supercapacitor, and dt is a variation value of the energy storage time.

According to the present invention configured as described above, by replacing the battery, such as a conventional lead-acid battery having a limit of life by the development of a charging device applying a supercapacitor to have a stable charging performance as well as to compensate for instantaneous voltage drop and stable operation and Together, it is possible to ensure a long service life with more than tens of thousands of charge and discharge performances, and there is an effect of effectively using the charged energy.

1 is a graph showing the voltage variation according to the use of the voltage charged in the portable energy charging device of the present invention,
2 is a circuit diagram of a supercapacitor of the present invention;
3 is a system block diagram of a portable energy charging device of the present invention;
4 is an overall circuit diagram showing a system of the portable energy charging device of the present invention.

Hereinafter, a portable energy charging apparatus using a supercapacitor of the present invention and a method of selecting a supercapacitor capacity of the apparatus will be described in detail with reference to the accompanying drawings.

First, a portable energy charging device using a supercapacitor according to the present invention is a portable device for temporarily storing and maintaining an energy capacity level so that energy generated by a conventional solar cell module 10 is used in a place without irradiation of light energy. In the energy charging device, a supercapacitor is applied to the portable energy charging device in order to improve charging and discharging characteristics to maintain charging performance.

The supercapacitor 20 is configured to be connected in parallel with the solar cell module 10 to store energy generated by the solar cell module 10.

의 기본적인 특성 주파수,

와 관련된다. 그러므로 수초에서 수십초의 백업시간에 응용되고, 10Hz보다 낮은 AC신호에 주로 사용된다.Such supercapacitors (Electric double layer capacitors, EDLC) are not limited in cycle life, and environmentally friendly materials that do not contain toxic substances, supercapacitors are emerging as energy storage devices that can replace and use batteries. . Supercharged magnetic power supplies (SMES), compressed air devices, accumulators, superconducting flywheel energy chargers (FES) are the main sources of energy charging. Etc. is an important comparison factor. Supercapacitors accumulate charge using electrochemical Faraday reaction principles such as adsorption reactions or oxidation-reduction reactions with electron transfer, and refers to capacitors with very large capacities from less than 1F to over 50KF. Also called an ultracapacitor. Supercapacitors have a low amplitude, such as transient currents in batteries and low amplitudes in batteries, and are used to match load levels, such as alternating current signals. DC charge / discharge time is the capacitor of AC voltage

Basic characteristics of the frequency,

Related to. Therefore, it is applied for backup time of several seconds to several tens of seconds and is mainly used for AC signal lower than 10Hz.

In particular, since the supercapacitor does not involve chemical change at the electrode interface during charge and discharge, the output capacitor is much higher than the storage battery, and the amount of energy charged and discharged per unit time can be maximized. It also has the ability to supply instantaneous peak power more than a few tens of times the capacity of a battery and to supply energy when a large amount of power is needed.

Supercapacitors (EDLC) have a low withstand voltage of 2 to 5V per unit, and a plurality of supercapacitors (EDLC) need to be connected in series to obtain a high voltage. This characteristic causes problems such as unbalanced voltage of supercapacitor EDLC, overvoltage breakdown due to application of voltage higher than breakdown voltage, and reduction of power storage energy. Therefore, in order to protect the supercapacitor from overvoltage, a voltage balancing circuit in which the voltage of each supercapacitor is equalized is inevitable.

In the case of applying a supercapacitor, constant voltage control must be performed, and a general voltage balance circuit using a zener diode is also used. As shown in the circuit of FIG. 2, a voltage balance circuit operates to connect a Zener diode (breakdown voltage = maximum voltage of EDLC) in parallel to each supercapacitor EDLC. The voltage balance circuit in the figure balances the voltage of each capacitor by bypassing the charging current to the resistor when the voltage of the capacitor becomes higher than a predetermined value during charging, and also has an overvoltage protection function.

Portable energy charging device of the present invention is a system that applies a supercapacitor to improve the charge and discharge characteristics as described above, when connected in parallel to the solar cell module to take charge of the instantaneous energy supply when the load suddenly increases or decreases When the supercapacitor is applied, a control device is installed to adjust power supply and demand between the solar cell module 10 and the supercapacitor 20.

Figure 3 shows a system block diagram of a portable energy charging device, the control device applied in the present invention is the maximum power to control the energy generated through the solar cell module 10 to generate a maximum output in a low solar radiation or various conditions The output point tracking method is composed of a MPPT controller 30 and a constant voltage control converter 40 installed at a rear end thereof.

That is, the solar cell has an optimum point of maximum power point, which is an optimal point for transferring power from the battery to a load-in load, and the maximum power point is changed due to environmental conditions such as temperature and solar radiation. The voltage output is adjusted through a controller, and the MPPT controller 30 controls the voltage output to continuously find and track the maximum power point to increase the overall power generation efficiency.

In this case, the converter 40 may use a constant voltage control converter.

Therefore, the energy generated in the solar cell module is output adjusted and delivered to the capacitor bank 50 composed of a plurality of supercapacitors, and the energy stored in the capacitor bank 50 for a limited time is used by the load 60. will be.

The supercapacitor has two components, a capacitive component and a resistive component, where the capacitive component represents a change in voltage according to a change in energy, and the resistive component is a voltage due to equivalent series resistance (ESR). It means the change of. The number of cells in the supercapacitor must be determined by system variables that take into account maximum and minimum voltages, currents, and durations.

1 is a graph showing the amount of voltage according to the use of the voltage charged in the portable energy charger, Vmax is the operating voltage, Resistive (ESR, equivalent series resistance) is the voltage drop due to ESR, Capacitive is the discharge of the capacitor Vmin is the minimum voltage due to the minimum voltage during the system or discharge time, and T is the discharge time.

As shown in the figure, the charged energy is discharged after being used for T hours, and the electricity generated through the solar cell module after discharge is charged in the supercapacitor having a usage time of T hours.

Here, the capacitive component is determined by the following formula [1].

[One]

Where I is the current, C is the capacitance, dV is the change in voltage, and dt is the change in time.

In addition, a resistance component is determined by following formula [2].

[2]

Where V is the voltage drop of the resistor, I is the current, and R is the equivalent series resistance (ESR).

When charging and discharging of a supercapacitor including both a capacitive component and a resistive component is performed, the variation of the total voltage is shown in Equation [3] below.

[3]

Due to the characteristics of supercapacitors with low rated voltage, how many cells are connected in series is determined by dividing the maximum voltage of the application target by the maximum allowable cell voltage, where the maximum allowable cell voltage is determined by the lifetime and temperature characteristics. Is determined. In general, the allowable voltage of each cell is about 2.5 ~ 5.5V.

4 is a circuit diagram showing a system of a portable energy charging device, according to the charged energy storage time is required to configure the circuit by connecting as many supercapacitors in series or in parallel, which is installed between the solar cell module and the supercapacitor bank. In order to control the MPPT controller 30 in a step-down manner, a microcontroller for detecting the output current and voltage is connected to the circuit.

At this time, the remaining capacity display means is further provided to check the remaining capacity of the energy charged in the supercapacitor bank, so that the portable charging device can be functionally supplemented, thereby improving convenience of use.

On the other hand, the supercapacitor 20 applied to the portable energy charging device is configured to configure the circuit by selecting the size according to the required energy storage time, in the present invention, portable energy to store the energy generated by the solar cell module 10 As a method for optimally selecting the capacity of the supercapacitor 20 applied to the charging device, the optimum size (capacity) of the supercapacitor was determined through respective parameters such as the operating voltage of the portable energy charging device.

The decision process can be divided into three stages. The first is to determine the basic parameters, the second is to determine the current and supercapacitor voltage fluctuations, and the third is to determine the capacitance. The capacity of the supercapacitor was selected optimally.

The first is a process of determining the basic parameters of the energy charger, namely the maximum and minimum operating voltage, the generated power and the energy storage time, and the second is the average current value and the supercapacitor of the charging system using these basic parameters. The third step is to determine the value of the voltage variation, and the third is to select the capacity of the supercapacitor by determining the total capacitance value required by the charging system according to each value determined in this process.

Referring to one embodiment,

The basic system parameters of the portable energy charger are Vmax = 18V, Vw = 16V, minimum voltage Vmin = 12V, power generation P = 15W, and energy storage time T = 1800s.

In the second step, dV is given by Equation [4] below to determine a parameter according to the determinant of dV.

[4]

When I is the average current, the average value is determined by dividing the maximum value and the minimum value by two. Therefore, the maximum value of I is given by Equation [5].

[5]

The minimum value of I is given by Equation [6].

[6]

Therefore, the average current is given by Equation [7].

[7]

Here, when the cell voltage of the supercapacitor is 5.5V, the maximum operating voltage is 18V, so it is 3.27 when divided by 5.5V, and when four supercapacitors are connected in series, it becomes 22V and 20% more than the maximum operating voltage of 18V. By having a margin of, it is possible to have a sufficient allowable voltage level.

And thirdly, when the capacitance value is calculated, as shown in Equation [8] below

[8]

As described above, in order to select the optimum capacity of the supercapacitor, the charge and discharge time was set to 30 minutes, which is 1,800s, and as a result, the total capacitance value of the portable energy charging device was 468F, and four 5.5Vdml supercapacitors were connected in series. When connected, a sufficient allowable voltage level can be achieved at 22V higher than the maximum operating voltage.

At this time, if the capacitance value of the supercapacitor used is 100F, four supercapacitors are connected in series, so the capacity of one supercapacitor is 25F, and the parallel connection of 18.72, that is, 19 parallel connection must be made. With the required capacity of 468F, energy can be used in an indoor environment with no solar conditions for 30 minutes after charging.

10: solar cell module 20: supercapacitor
25: constant voltage protection circuit
30: Maximum Power-Point Tracking Controller
40: converter 50: supercapacitor bank
60: load

Claims (5)

In the portable energy charging device for temporarily storing the energy generated by the solar cell module 10 to use in a place without irradiation of light energy and maintain the energy capacity level,
Supercapacitor bank (50) consisting of one or more supercapacitors (20) connected in parallel with the solar cell module (10) to store energy generated by the solar cell module (10) is connected to a supercapacitor. Portable energy charger.
The method of claim 1,
Portable energy charging device using a supercapacitor, characterized in that the constant voltage protection circuit 25 is connected in parallel to the supercapacitor 20 so as to equalize the voltage of each supercapacitor 20 to protect it from overvoltage.
The method according to claim 1 or 2,
The control device is installed between the solar cell module 10 and the supercapacitor bank 50 to control power supply and demand.
The control device, for the constant voltage control installed in the MPPT controller 30 of the maximum power output point tracking method for controlling the energy generated through the solar cell module 10 to generate the maximum output in a low solar radiation or various conditions Portable energy charging device using a supercapacitor, characterized in that composed of a converter (40).
In the capacity selection method of the supercapacitor 20 applied to the portable energy charging device to store the energy generated by the solar cell module 10,
Determining basic parameters (maximum and minimum voltage, generated power, energy storage time) of the energy charging device; Determining an average current value and a voltage variation value of the supercapacitor using the basic parameters; Determining the total capacitance value required by the energy charger according to the determined average current value and the voltage variation value of the supercapacitor; Supercapacitor capacity selection method of the portable energy charger, characterized in that for selecting the capacity of the supercapacitor .
The method of claim 4, wherein
When the maximum voltage value of the portable energy charger is Vmax, the minimum voltage value Vmin, and the maximum voltage value Vw of the capacitor,
The voltage fluctuation value is a voltage drop due to the discharge of the supercapacitor, and dV = Vw-Vmin,
The total capacitance value C is formed by the equation

I is an average current value flowing through the energy charging device, dV is a voltage variation value of the supercapacitor, and dt is a variation value of the energy storage time.

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