WO2006001088A1

WO2006001088A1 - Solar cell-type charger

Info

Publication number: WO2006001088A1
Application number: PCT/JP2004/010755
Authority: WO
Inventors: Shoji Ichimura
Original assignee: Firac International Co., Ltd.
Priority date: 2004-06-24
Filing date: 2004-07-22
Publication date: 2006-01-05

Abstract

A construction of solar cell-type charger capable of charging a variety of types of batteries for use in mobile equipment. A capacitor (11) is connected in parallel with a battery (3) and a solar cell (2), and a coil (13) and a diode (14) are connected in series between the solar cell (2) and the parallel circuit formed by the capacitor (11) and the battery (3), or, alternatively, the coil (13) and the diode (14) are connected in series with the solar cell (2) and the battery (3), and the capacitor (11) is connected in parallel with the series circuit formed by the diode (14) and the solar cell (2) and with the series circuit formed by the coil (13) and the battery (3). Then a switching element (15) connected in parallel with the series circuit formed by the capacitor (11) and the diode (14) is controlled by a control circuit (16), or a switching element (15) connected in series between the coil (13) and the diode (14) is controlled by the control circuit (16).

Description

Solar battery charger

Technical field

Light

The present invention uses a solar cell as a power source to charge a mobile phone or other mopile device.

The present invention relates to a solar cell type charging device.

BACKGROUND ART In recent years, mobile phones and other mopile devices are widely used, and as a charging device for them, a method of charging a mobile phone from a commercial power source (AC power supply 100 V, etc.) using an AC adapter or the like is common. However, for the case where the AC outlet power source cannot be used, recently, as a charging device for a mobile phone, a disposable charger using a dry cell as a power source or a charger for a mobile phone using a solar cell as a power source has been developed. It is commercially available. In the case of a disposable charger powered by a dry battery, the dry battery becomes disposable each time, and a new dry battery must be purchased for the next use, which is undesirable in terms of cost and waste of resources. In addition, since solar cells basically do not have a power storage function, simply installing a solar cell cannot use it when it can receive sunlight in a clear daytime. In addition, solar cells that can be adapted to mobile phones are not designed according to the standard size. Because it is always limited, the charging current to the mobile phone is small, and the talk time cannot be guaranteed with a short charging time.

Reflecting the situation described above, in recent years, a configuration using a power storage device using a solar cell has been proposed for mopile equipment, but the storage voltage of the charging device and the generated voltage of the solar cell do not necessarily match. Therefore, it has been proposed that the charging voltage of the storage battery be set within an appropriate range by interposing a DC ZD C damper between the solar battery and the storage battery.

However, there are various types of storage batteries required for mopile equipment, and by simply interposing the D CZD C inverter as described above, appropriate charging voltages can be set for various storage batteries. I can't do it.

However, in the prior art, a charging device using a solar cell based on a specially devised configuration of a DC / DC inverter that can cope with various storage batteries used in mopile equipment has not been developed so far. It was. Disclosure of the invention

In the present invention, in consideration of the above-mentioned background facts, the DCZ DC damper that can easily correspond to the charging voltage to be set for various storage batteries used in the mopile device is adopted. It is an object to provide a configuration related to a charging device using a solar cell. In order to solve the above problems, the basic configuration of the present invention is as follows.

(1) In a solar battery charger using a D CZD C inverter interposed between a solar cell and a storage battery, a capacitor (C ) And a coil (L) and a diode between the capacitor (C) and the parallel circuit of the storage battery and the solar battery.

(D) is connected in series, and the switching element is connected in parallel to the series circuit consisting of the capacitor (C) and the diode (D), and when the charging voltage for the storage battery reaches the upper limit value, Install a control circuit that turns on the switching element and turns off the switching element when the charging voltage reaches the lower limit value, or connects the switching element in series between the coil (L) and the diode (D). A control circuit that turns off the switching element when the charging voltage to the storage battery reaches the upper limit and turns the switching element on when the charging voltage reaches the lower limit. A solar battery charger based on the adoption of the step-up (step-up) configuration

(2) In a solar battery charger with a DC / DC inverter interposed between a solar battery and a storage battery, a coil (L ) Connect the diode (D) and connect the capacitor (C) to the series circuit of the diode (D) and solar cell, and coil

Connect the switching element in parallel to the series circuit consisting of the capacitor (C) and the diode (D). Then, when the charging voltage for the storage battery reaches the upper limit value, turn on the switching element, and when the charging voltage reaches the lower limit value, install a control circuit to turn off the switching element, or switch The element is connected in series between the coil (L) and the diode (D), and when the charging voltage for the storage battery reaches the upper limit value, the switching element is turned OFF, and the charging voltage reaches the lower limit value. At this stage, a solar cell type charging device based on adopting a step-down type configuration by installing a control circuit that turns on the switching element.

Power.

Based on the basic configurations of (1) and (2), the present invention realizes stable charging for storage batteries with various charging voltages, and thus economical use of power for mopainole equipment. Is possible,

Furthermore, depending on the embodiment, it is possible to set the charging voltage corresponding to various types of secondary storage batteries provided in each mopile device by using one solar battery charger. It becomes possible to extend the life of the secondary storage battery of the type. Brief Description of Drawings

Figure 1 shows the configuration of the above-mentioned (1) employing a step-up DC / DC inverter. (A) shows the case of a parallel switch configuration, and (b) shows the case of a series switch configuration. Is shown. Figure 2 shows the configuration of (1) above, which uses a step-down DC / DC inverter. (A) shows the case of a parallel switch configuration, and (b) shows the case of a series switch configuration. Is shown.

Fig. 3 shows a graph showing the rising and falling states of the charging voltage.

FIG. 4 shows a block circuit representing the basic configuration of the embodiment.

Fig. 5 shows a flowchart for identifying the type of secondary storage battery. The invention's effect .

In the present invention based on the basic configurations (1) and (2), stable charging can be realized for storage batteries with various charging voltages, and economical power can be used for mopile equipment. And

In particular, in each of the inventions described in claims 3 to 5, the charging voltage is set by one solar battery type charging device corresponding to various types of secondary storage batteries provided in each mopile device. It is possible to extend the life of various types of secondary storage batteries. BEST MODE FOR CARRYING OUT THE INVENTION

The configuration of (1) employs a step-up type DCZDC inverter 1, and the embodiment is shown in FIGS. 1 (a) and 1 (b). A capacitor in parallel with storage battery 3 and solar cell 2 as C

(C) 11 is connected, and a coil (L) 12 and a diode (D) 14 are connected in series between the parallel circuit of the capacitor (C) 11 and the storage battery 3 and the solar battery 2.

Fig. 1 (a) shows switching element 15 with capacitor (C) 11 and diode

(D) When connected in parallel to the series circuit of 14 and when the charging voltage for the storage battery 3 reaches the upper limit value, the switching element 15 is turned ON and the charging voltage reaches the lower limit value. Adopting a parallel switch configuration by installing a control circuit 16 that turns off the switching element 15.

Fig. 1 (b) shows the switching element 15 connected in series between the coil (L) 12 and the diode (D) 14, and when the charging voltage for the storage battery 3 reaches the upper limit, A series switch configuration is adopted in which a control circuit 16 is installed that turns the switching element 15 ON when the charging voltage reaches the lower limit when the charging voltage reaches the lower limit.

In Fig. 1 (a) and (b), the adjusting resistor (R) 13 is connected in series to the terminal of the capacitor (C) 11 and the storage battery 3, but the adjusting resistor (R) 13 is not necessarily Not essential.

Actually, since the internal resistance of the storage battery 3 is not necessarily constant, the adjustment resistor (R) 13 is often used in order to stabilize the charging voltage.

On the other hand, in Fig. 1 (a), solar power is used for the purpose of storing a sufficient charge. A spare capacitor (C ') is connected in parallel to the series circuit consisting of pond 2, coil (L) 1 2 and switching element 15; however, the spare capacitor (C') is not necessarily indispensable. Absent.

However, when setting a particularly high charging voltage, a spare capacitor (C) is often set to obtain a sufficient amount of electricity.

In order to explain the basic principle of the parallel switch type DCZD C inverter 1 shown in Fig. 1 (a), as shown in Fig. 3, the lower limit value of the voltage within the range that allows charging of the storage battery 3 is shown. In addition, the upper limit value V ₂ of the voltage value that does not lead to destruction of the storage battery 3 during charging is set, and as described above, the switching element 1 5 is set according to the command from the control circuit 16. The battery is charged based on the voltage within the range of the upper limit value and the lower limit value while repeatedly charging and discharging the capacitor (C) 11.

The operation of the parallel switch type configuration shown in FIG. 1 (a) will be described in more detail. When the control circuit 16 determines that the upper limit value is satisfied, the switching element 15 is turned ON. The capacitor (C) 1 1 discharges the electric charge stored on the basis of the electromotive force of the solar cell 2 so that the voltage at both ends sequentially decreases, but during that time, it passes through the coil (L) 1 2 And the current i passing through the closed circuit formed by the switching element 15 is

If the electromotive force of solar cell 2 is e,

e = Ldi / dt When the discharge time is set to At, the current increase amount Δ i! Is

e = L · Δ i J ΖΔ t ₁

By

Δ i! = E · Δ t! / L (1)

It is.

When the charging voltage reaches the lower limit due to the decrease caused by the discharge, the switching element 15 is brought to the OF F state by the determination of the control circuit 16, and the power storage in the capacitor (C) 11 is generated. (C) 11 The voltage on both sides of 1 1 rises, so the charging voltage for storage battery 3 rises, but the voltage across coil (L) 1 2 falls as the voltage rises.

For this reason, the current (i) passing through the coil (L) 1 2 is, when the magnitude of the charging voltage applied to the adjusting resistor (R) and the storage battery 3 is V,

e -V = L · d i! / d t

When the charging time is At ₂ and the upper limit value of the charging voltage is V ₂ , the current decrease amount Δ i ₂ is e − V ₂ = -L · Δ i ₂ , Δ t ₂

Is established,

Δ i ₂ ^ (V ₂ -e) · Δ t ₂ / L (2)

It is. Δi! The start stage of the current increase to reach Δ i ₂ corresponds to the end stage of the decrease of the current reaching Δ i _2, and the end stage of the current increase reaching Δ i ₁ is represented by Δ i _{2 described above} . From the beginning of the current reduction

Δ i! = Δ i ₂

Is established.

Therefore, from the equations (1) and (2),

e · Δ t! / L = (V ₂ -e) · Δ t ₂ / L

Is established,

V ₂ = (Δ t _x + Δ t ₂ ) e / Δ t ₁

The above upper limit value V ₂ is clearly larger than the electromotive voltage e generated by the solar cell 2.

Corresponding to the fact that the upper limit value V ₂ force is larger than the electromotive voltage e generated by the solar cell 2, the capacitor (C) also has a voltage of the upper limit value V ₂ when the charging voltage reaches the upper limit value V ₂ . has been power storage in respect condenser (C), the you described are possible power storage due to a voltage larger than the electromotive voltage e by the solar cell 2, at the stage where the upper limit value V ₂ occurs, the coil The current (i) that conducts (L) has suddenly changed from the previous decrease stage to the increase stage. For this reason, the coil (L) has a large voltage due to the differential form L · di / dt. As a result, the upper limit value V ₂ is larger than the electromotive voltage e generated by the solar cell 2 because e + which is the electromotive voltage of the solar cell 2 and a large voltage due to L · di / ά t is generated. To voltage Power storage is performed.

On the other hand, at the stage where the charging voltage reaches the lower limit value V, the current (i) that conducts the coil (L) has suddenly changed from the previous increase stage to the decrease stage. In (L), due to the differential form of L · di / dt, an equivalent tree-like voltage is generated in the reverse direction. This reverse voltage is caused by the presence of the diode (D) 14 and the capacitor (C ) Does not affect 11.

The minimum charge voltage is

V ₁ = V ₂ -Δ i! · Δ t _x / C = V _2- (e · Δ t! ² ) / (C · L).

In actual design, in the second term of the approximate expression for the minimum value,

Δ t! ² <CL

Therefore, the lower limit value according to the approximate expression is also larger than the electromotive voltage due to the solar cell 2.

Would otherwise, by excessive phenomenology based on such so-called Laplace transform, the lower limit value of the charging voltage and the upper limit value V ₂ and each initial voltage value, and is the circuit element and the electromotive force e Ru good solar cells 2 Coil (L) 12 and capacitor (C) 11 and solar battery 2 The internal resistance (R.), adjustment resistance (R) 13, etc. Capacitor as shown in Fig. 3

(C) It is possible to obtain each voltage in the rising stage of the charging voltage accompanying the storage of 11 and in the falling stage of the charging voltage accompanying discharging of the capacitor (C) 11. As shown in Fig. 1 (a), the approximate expression of V, V ₂ and e as described above can be used without the complicated calculation necessary for elucidating the voltage change state due to the exponential function. It can be explained that boosting (step-up) is possible in DCZDC Inverter 1.

In the case of the series switch configuration shown in Fig. 1 (b), the ON / OFF of the switching element 15 is only reversed from that in Fig. 1 (a), and the basic principle is exactly the same. (In the case of the series switch configuration of Fig. 1 (b), Fig. 1

As shown in (a), at the stage where the charging voltage drops after the provision of a spare capacitor), even if discharge is performed in the same manner as capacitor (C) 11, switching element 15 is turned OFF at this stage. Therefore, in the case of the series switch configuration shown in Fig. 1 (b), no reserve capacitor (C ') is provided. )

That is, the control circuit 16 sets the switching element 15 to the OFF state when the charging voltage reaches the upper limit value, and sets the switching element 15 to the ON state when the charging voltage reaches the lower limit value. As shown in Figure 3, the capacitor

(C) The charging voltage rise due to 11 storage and the charging voltage fall due to discharge are repeated.

The configuration of (2) employs a step-down type DCZDC inverter 1, and the embodiment thereof includes a solar cell 2 and a storage battery as shown in FIGS. 2 (a) and 2 (b). 3 for coil (L) 12 and diode (D) 14 in series The capacitor (C) 1 1 is connected in parallel to the series circuit composed of the diode (D) 14 and the solar battery 2 and the series circuit composed of the coil (L) 12 and the storage battery 3.

That is, as is clear from the comparison with the circuits shown in FIGS. 1 (a) and 1 (b), in the DC / DC inverter 1 shown in FIGS. 2 (a) and (b), the coil (L) 12 is connected to the capacitor. (C) When 11 is used as a reference, it is different in that it is connected in series to the storage battery 3 side instead of the solar battery 2 side.

In Fig. 2 (a), the switching element 15 is connected in parallel to the series circuit of the capacitor (C) 11 and the diode (D) 14, and when the charging voltage for the storage battery 3 reaches the upper limit value, When the switching element 15 is turned on and the charging voltage reaches the lower limit value, the parallel switch configuration is shown by installing the control circuit 16 that turns off the switching element 15.

In FIG. 2 (b), the switching element 15 is connected in series between the coil (L) 12 and the diode (D) 14, and the switching element 15 is turned on when the charging voltage for the storage battery 3 reaches the upper limit. A series switch configuration is shown in which a control circuit 16 is provided in which the switching element 15 is in an ON state when the charging voltage reaches a lower limit value.

In the case of the step-down type shown in Fig. 2 (a) and (b), the preparation shown in Fig. 1 (a) is necessary to obtain a sufficient amount of electricity for the purpose of high charging voltage. Since it is not necessary to install a capacitor (C '), it is usually done. Absent.

To explain the operation of the parallel switch configuration shown in Fig. 2 (a), when the charging voltage to the storage battery 3 reaches the lower limit value V, the switching element 15 is turned off by the discrimination of the control circuit 16. The capacitor (C) 11 is stored, and the adjustment resistor (R) 13 and the charging voltage applied to the storage battery 3 are increased.

In this process of increasing the storage and charging voltage, the charging voltage V generated at both ends of the adjustment resistor (R) 13 and the storage battery 3 is R. The internal resistance of the storage battery 3 is R. Is based on the so-called transient phenomenon theory,

v _{= e} ^L · * / ^{(R + R} °} (3)

(However, the start time of the rise of the storage and charging voltage is set to t = 0.) If the elapsed time t is sufficiently small, it is roughly e · L t / (R + R.) Equal to ² .

As is clear from the above equation (3), the lower limit value and the upper limit value of the charging voltage in the process of increasing the charging and charging voltage for the capacitor (C) 11 depend on the intermediate value between 0 and e. The value is clearly smaller than the electromotive voltage e of the solar cell 2.

When the charging voltage reaches the upper limit value, the switching element 15 is turned on by the operation of the control circuit 16, and the charging voltage is gradually lowered from the upper limit value to the lower limit value by discharging the capacitor (C) 11. This point is shown in Fig. 1 (a). Same as the case. .

In the case of the series switch configuration shown in Fig. 2 (b), the ON / OFF of the switching element 15 is only reversed as in Fig. 2 (a), and the basic principle is exactly the same. .

(C) The charging voltage rise due to 11 power storage and the charging voltage fall due to discharge are repeated (in other words, the lower limit value and the upper limit value V _{2 based on} the unit of the rise and fall are Both values are smaller than the electromotive voltage e of the solar cell 2, which is different from the case of Fig. 1 (b).

As is clear from FIGS. 1 (a) and 1 (b) and FIGS. 2 (a) and 2 (b), the DCZDC inverter 1 according to the present invention has an upper limit value or a lower limit for the charging voltage or charging current for the storage battery 3. It is characterized in that the control circuit 16 determines that the value has been reached, and thereby the switching element 15 is turned on or off, but the upper limit value and the lower limit value are used. It is possible to set appropriately corresponding to the storage battery 3.

Therefore, when the control circuit 16 employs, for example, two comparison circuits (comparator circuits) to determine the arrival of the upper limit value and the lower limit value, the reference voltage in the comparison circuit is set to Various adjustments can be made It corresponds to the charging voltage of the storage battery 3 and can be adapted.

On the other hand, when the control circuit 16 is linked to a microcomputer, the microcomputer selects the upper limit value and the lower limit value, and the value of the charging voltage that is sequentially input becomes the upper limit value or When a command signal corresponding to ON or OFF is generated for the control circuit 16 based on determining whether or not the lower limit value is met, it can be applied to charging various storage batteries 3. For example, a transistor, FET, or MOSS can be used as the switching element 15. Example

In the embodiment, the control circuit 16 is interlocked by a microcomputer, the upper limit value and the lower limit value as described above are selected, and the value of the charging voltage sequentially input becomes the upper limit value or the lower limit value. It is premised on a configuration in which it is determined whether or not they match, and a command signal corresponding to ON or OFF is generated for the control circuit 16.

Based on such a microcomputer configuration, as shown in FIG. 4, a secondary storage battery 4 that is further charged from the storage battery 3 is installed and a thermistor 5 that measures the heat generation temperature in the secondary storage battery 4 is installed. The temperature information from the thermistor 5 is transmitted to the microphone port computer, and the microcomputer In the data, the exothermic temperature or exothermic temperature range corresponding to each secondary storage battery 4 type is recorded in advance, and after checking the transmitted exothermic temperature, the type of secondary storage battery 4 is specified. According to the specified secondary storage battery 4, the upper limit value and the lower limit value of the charging voltage are selected.

Most of the types of storage batteries 3 that mopile equipment has are lithium-ion batteries, nickel-cadmium batteries, and nickel-metal hydride batteries. However, the user chooses the type of storage battery that is used. There are many cases that do not know.

In the embodiment, paying attention to the difference in heat generation temperature in each type of secondary storage battery 4 as described above, a thermistor 5 for measuring the temperature generated by the secondary storage battery 4 is installed, and the output of the thermistor 5 is micro- By transmitting to the computer, the microcomputer discriminates the type of the secondary storage battery 4 and selects the upper limit value and the lower limit value suitable for the secondary storage battery 4.

In addition, the broaching when the type of the secondary storage battery 4 is specified from the temperature of the thermistor 5 is as shown in FIG.

When the type of the secondary storage battery 4 is determined by the microcomputer based on the flowchart as described above, the result of the determination is optically displayed. Based on the display, For example, a configuration in which the upper limit value and the lower limit value suitable for each secondary storage battery 4 are selected by a manual operation such as selecting and pressing a button can also be adopted. Industrial applicability

The present invention can be used for any of the devices for charging the storage battery 3 possessed by these mopile devices as the secondary storage battery 4 when directly employed as the power source of the mopile device itself such as a mobile phone or a portable personal computer. Is possible.

Claims

The scope of the claims

1. In a solar battery charger with a DCZDC inverter interposed between a solar battery and a storage battery, a capacitor (C) is connected in parallel to the storage battery and the solar battery as a DC / DC inverter. A coil (L) and a diode between the parallel circuit of the capacitor (C) and the storage battery and the solar battery.

After connecting (D) in series, the switching element is connected in parallel to the series circuit consisting of the capacitor (C) and the diode (D), and when the charging voltage for the storage battery reaches the upper limit value, Install a control circuit that turns on the switching element and turns off the switching element when the charging voltage reaches the lower limit value, or connects the switching element in series between the coil (L) and the diode (D). A control circuit that turns off the switching element when the charging voltage to the storage battery reaches the upper limit and turns the switching element on when the charging voltage reaches the lower limit. Solar battery charger based on the adoption of a step-up (step-up) configuration.

2. In a solar battery charger using a DCZDC inverter interposed between a solar battery and a storage battery, a coil (L) and a diode (in series) are connected in series to the solar battery and storage battery as a DC / DC inverter. D) and a capacitor (C) are connected in series with a diode (D) and a solar cell, and a coil (L) Connected in parallel to a series circuit consisting of a battery and a storage battery, and then connecting a switching element in parallel to a series circuit consisting of a capacitor (C) and a diode (D), the charging voltage for the storage battery reached the upper limit. At the stage, when the switching element is turned on and the charging voltage reaches the lower limit value, install a control circuit that turns off the switching element, or connect the switching element to coil (L) and diode (D) Is connected in series, and when the charging voltage for the storage battery reaches the upper limit value, the switching element is turned OFF, and when the charging voltage reaches the lower limit value, the switching element is turned ON. A solar battery-type charging device based on the adoption of a step-down (step-down type) configuration by installing a control circuit to be in a state.

3. The control circuit and the microcomputer are linked together, and the computer selects the upper and lower limit values of the charging voltage corresponding to the storage battery. 3. The solar cell charging device according to claim 1, wherein it is determined whether or not a value or a lower limit value is met.

4. Install a secondary storage battery that is further charged from the storage battery, install a thermistor that measures the heat generation temperature in the secondary storage battery, and transfer temperature information from the thermistor to the microphone port computer. In, the heat generation temperature or the heat generation temperature range corresponding to each secondary storage battery type is recorded in advance, and the type of the secondary storage battery is identified by comparing with the transmitted heat generation temperature. 4. The solar cell charging device according to claim 3, wherein an upper limit value and a lower limit value of the charging voltage are selected corresponding to the specified secondary storage battery.

5. Install a secondary storage battery that is further charged from the storage battery, install a thermistor that measures the heat generation temperature of the secondary storage battery, and optically select the corresponding secondary battery type based on temperature information from the thermistor. 4. The solar cell charging device according to claim 3, wherein a manual device for selecting an upper limit value and a lower limit value of the charging voltage based on the display is installed.

6. The solar battery type charging device according to claim 4 or 5, wherein the plurality of secondary storage batteries are any one of a lithium ion battery, a nickel cadmium battery, and a Nikkenore hydrogen battery.