JP2010051106A - Power supply system - Google Patents

Abstract

An object of the present invention is to simply and efficiently provide power charged in a storage battery to a load including illumination according to the remaining capacity.
An assembled battery 3 that performs charging using power generated by a solar cell 1 supplied via a converter 2 and that discharges when power supplied to a load 4 is insufficient, and the solar cell 1 When the generated load or the load 4 is operated using the power discharged from the assembled battery 3, and the load 4 includes the environment observation device 41 and the illumination 42 as an important load, the illumination 42 is 1 It comprises a set diode 42a in which two or more light emitting diodes are connected in series, and a current limiting resistor 42b. The number of light emitting diodes constituting the assembled diode 42a is such that the forward voltage of the assembled diode 42a is smaller than the highest charging voltage of the assembled battery 3 and is within a predetermined range with respect to the lowest discharge voltage of the assembled battery 3. To be a certain value.
[Selection] Figure 1

Description

  The present invention relates to a power supply system.

  Conventionally, a solar cell system combining a solar cell and a storage battery has been used as a power source for a load installed in a place where it is difficult to secure a power infrastructure. For example, in a solar cell system, the electric power generated by the solar cell is supplied to the load during the daytime, the storage battery is charged with surplus power, and the electric power necessary for the load is covered by the discharge from the storage battery at night.

  A specific configuration example of such a solar cell system will be described with reference to FIG. FIG. 4 is a diagram for explaining the prior art.

  As shown in FIG. 4, the conventional solar cell system is composed of a solar cell, a converter, and an assembled battery, and is further connected to a load that operates using electric power supplied from the solar cell system.

  The solar cell is a device that generates electric power by sunlight, and the assembled battery has a configuration in which a plurality of storage batteries are connected in series or in parallel. The converter is a device that converts DC power generated by the solar battery into a voltage that can be received by the assembled battery and the load.

  In the solar cell system having such a configuration, when the generated power of the solar cell is sufficiently large and the output power of the converter exceeds the required power of the load, the surplus is supplied to the assembled battery to configure the assembled battery. Charging is performed by the storage battery. Conversely, when the power supplied to the load is insufficient with the generated power of the solar battery, the insufficient power is supplemented by the discharge of the assembled battery. As a result, the solar cell system can supply power to the load not only at night without sunlight but also at daytime when the weather worsens.

  In addition, once the generated power of the solar battery is stored in an electric double layer capacitor (capacitor), the battery is supplied with the desired voltage and current, thereby efficiently charging the battery without overcharging or insufficient charging. A stand-alone photovoltaic power generation system that can do this is known (for example, see Patent Document 1).

  In addition, once the generated power of the solar cell is stored in the electric double layer capacitor, the desired voltage and current are distributed and supplied to multiple storage cells, thereby reducing the power flowing through each storage battery and configuring the system. A stand-alone photovoltaic power generation system that can realize a reduction in size and price of a storage battery is also known (see, for example, Patent Document 2).

  On the other hand, the load connected to the solar cell system or the stand-alone photovoltaic power generation system is operated by the power supplied from the solar cell or the assembled battery. If the battery continues for a long time, the remaining capacity of the assembled battery (storage battery) decreases. Finally, the discharge is terminated and the power supply to the load is stopped, so that the operation is stopped.

  Here, the load is composed of lighting that functions as a street light by turning on at night and a weather observation device that measures, for example, the amount of solar radiation and temperature, and because weather observation is important for disaster prevention, There are cases where it is desirable to prioritize the operation of the weather observation device over the operation of the lighting.

  In such a case, a threshold value is set for the remaining capacity of the assembled battery, and when the remaining capacity falls below the threshold value, power from the assembled battery is supplied only to the weather observation apparatus. It is necessary to extend the operation period.

  For this reason, for example, a method in which a switch is inserted in a power supply line for lighting and the switch is turned off when the voltage of the assembled battery falls below a preset voltage is applied to a solar cell system or a stand-alone photovoltaic power generation system. Thus, when the remaining capacity of the assembled battery decreases, the operation period of the weather observation apparatus can be extended by stopping the illumination operation and operating only the weather observation apparatus. That is, it is possible to efficiently provide the power charged in the assembled battery (storage battery) to the load according to the remaining capacity.

  Even if the load consists only of lighting, applying the same method to a solar cell system or a stand-alone photovoltaic power generation system will stop the lighting operation when the remaining capacity of the assembled battery is reduced. The overdischarge of the battery can be avoided, and the power charged in the assembled battery (storage battery) can be efficiently provided to the load according to the remaining capacity.

JP 2000-250646 A JP 2001-069688 A

  By the way, in order to execute the above-described conventional technique, a voltage measuring device such as an A / D converter that measures the voltage of the assembled battery, a switch such as a field effect transistor (FET), and a voltage measuring device measure the voltage. A control circuit that determines whether the switch is open or closed based on the voltage value and sends a signal to the switch is required.

  That is, in order to efficiently supply the power charged in the storage battery to the load including lighting according to the remaining capacity, a switch and a control circuit such as a voltage measuring device and FET are added to the solar cell system and the stand-alone photovoltaic power generation system. There is a problem that it is necessary to incorporate the system, and the cost for configuring the system increases, and the failure rate may increase because the number of elements configuring the system increases.

  In addition, in a system in which a simple DC power supply (for example, an AC adapter, a primary battery, etc.) supplies power for charging to the storage battery instead of the solar battery, the power charged in the storage battery is efficiently used according to the remaining capacity. Even when providing to loads including illumination, the same problem has been encountered.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and simply and efficiently provides the power charged in the storage battery according to the remaining capacity for a load including illumination. An object of the present invention is to provide a power supply system that can achieve the above.

  In order to solve the above-described problems and achieve the object, this system includes a storage battery that performs charging and discharging using power generated by a predetermined DC power supply, and power supplied from the predetermined DC power supply or the storage battery. A power supply system including a load including a lighting that operates using the lighting, wherein the lighting is a grouped diode in which one or more light emitting diodes are connected in series, and the light emitting diode constituting the grouped diode The number of series is determined such that the forward voltage of the group diode is determined to be smaller than the maximum charging voltage of the storage battery and to be a value within a predetermined range with respect to the minimum discharge voltage of the storage battery. To do.

  According to the disclosed system, when the remaining capacity of the storage battery that continues to be discharged decreases due to insufficient power generated by the solar battery, and the voltage drops to the forward voltage of the assembled diode, lighting of the assembled diode is automatically stopped. It becomes possible to easily and efficiently provide the electric power charged in the storage battery according to the remaining capacity with respect to the load including illumination.

  Exemplary embodiments of a power supply system according to the present invention will be described below in detail with reference to the accompanying drawings.

  First, the configuration of the power supply system in the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of a power supply system according to the present embodiment.

  As shown in FIG. 1, the power supply system in this embodiment includes a solar cell 1, a converter 2, an assembled battery 3, a load 4, and a switch 5 with a timer.

  The solar cell 1 is a device that generates electric power from sunlight. For example, the solar cell 1 in the present embodiment has a power generation capability of a maximum of 90W. The solar cell 1 corresponds to a “predetermined DC power source” described in the claims.

  The converter 2 is a device that converts DC power generated by the solar battery 1 into a voltage that can be received by the assembled battery 3 and the load 4. For example, the converter 2 in the present embodiment is a DC / DC converter that can output a maximum of 16V.

The assembled battery 3 has a configuration in which a plurality of storage batteries are connected in series or in parallel, and is charged and discharged using electric power generated by the solar battery 1. For example, the assembled battery 3 in the present embodiment has a storage capacity of 1200 Wh in which 10 nickel-metal hydride storage cells having “rated voltage: 1.2 V, rated capacity: 100 Ah” are connected in series. Since one nickel metal hydride storage battery has a maximum charge voltage (V _H ) of 1.6 V and a discharge end voltage (V _L ) of 1.0 V, the assembled battery 3 in this example is “highest”. Charge voltage (Vcharge): 16V, discharge end voltage (Vcut): 10V ". Hereinafter, the discharge end voltage (Vcut) of the assembled battery 3 is referred to as the minimum discharge voltage (Vcut).

  Here, when the generated power of the solar cell 1 is sufficiently large and the output power of the converter 2 exceeds the required power of the load 4, the surplus is supplied from the converter 2 to the assembled battery 3 to constitute the assembled battery 3. Charging is performed in the nickel metal hydride storage battery cell. On the contrary, when the power supplied to the load 4 is insufficient with the generated power of the solar battery 1, the insufficient power is supplemented by the discharge of the assembled battery 3.

  The load 4 is a device that operates with electric power supplied from the solar cell 1 or the assembled battery 3, and the state in which the solar battery 1 continues to run short due to continuous unsunshine and the remaining capacity of the assembled battery 3 is maintained. When the discharge drops and the discharge ends, the operation is stopped.

  Here, the load 4 in the present embodiment includes an environment observation device 41 and an illumination 42 as shown in FIG. The environment observation device 41 is a device that measures the amount of solar radiation and the temperature, and the illumination 42 lights up at night and functions as a street light. Note that the observation target of the environment observation device 41 may be environmental pollutants such as ultraviolet rays, dust, and photochemical smog, and monitoring information for disaster prevention such as river water amount and seismic intensity other than the above meteorological data.

  Note that the environment observation apparatus 41 in this embodiment is set as an important load in which the operation is prioritized over the operation of the lighting 42 because weather observation is important for disaster prevention. Furthermore, the environment observation apparatus 41 is an apparatus operable in the range of “Vcharge to Vcut”.

  The switch 5 with a timer is attached to a power supply line for supplying power from the solar cell 1 or the assembled battery 3 to the illumination 42. For example, the illumination 42 is turned on only at night, from “6 pm to the next day. Until 6:00 am ”is set to be on. The timer-equipped switch 5 corresponds to “power supply control means” described in the claims. Here, in the present embodiment, the case where the timer-equipped switch 5 is used as the “power supply control means” has been described, but the present invention is not limited to this, and is based on the measurement results of the illuminometer and the illuminometer. The switch that operates may be used as “power supply control means”. That is, when the measurement result of the illuminometer falls below a predetermined illuminance during the daytime, the illumination is reduced during the period when the illuminance is reduced by turning on the switch attached to the power supply line for supplying power to the illumination 42. 42 may be set to be on.

  As described above, the power supply system in the present embodiment performs charging using the power generated by the solar cell 1 supplied via the converter 2, and the power supplied to the load 4 is generated by the generated power of the solar cell 1. The assembled battery 3 that discharges when it is insufficient, and the load 4 that operates using the power generated by the solar battery 1 supplied via the converter 2 or the power discharged from the assembled battery 3 (environmental observation as an important load) Device 41 and illumination 42).

  Here, the power supply system in the present embodiment is mainly capable of easily and efficiently providing the power charged in the assembled battery 3 to the load 4 including the illumination 42 according to the remaining capacity. There are features.

  This main feature will be described with reference to FIG. 2 together with FIG. In addition, FIG. 2 is a figure for demonstrating the conditions for installing the illumination in a present Example.

  As shown in FIG. 1, the illumination 42 in this embodiment includes a group diode 42a in which one or more light emitting diodes are connected in series, and a current limiting resistor used to adjust the voltage supplied to the group diode 42a. 42b.

  Here, the assembled battery 3 can supply power to both the environmental observation device 41 and the assembled diode 42a, which are important loads, but the light emitting diodes constituting the assembled diode 42a must apply a voltage exceeding the forward voltage. Does not emit light.

  Therefore, if an appropriate number of light emitting diodes are connected in series, the illumination 42 that does not emit light (does not consume power) can be created unless a voltage exceeding a predetermined voltage is applied.

  For this reason, the number of light emitting diodes constituting the assembled diode 42a is such that the forward voltage of the assembled diode 42a is smaller than the maximum charging voltage (Vcharge) of the assembled battery 3 and the lowest discharge voltage (Vcut) of the assembled battery 3 is. Is determined to be a value within a predetermined range.

  Specifically, if the number of light emitting diodes in series is “n” and the forward voltage of the single light emitting diode is “V1”, the conditional expression ““ minimum discharge voltage ”<“ forward voltage of the assembled diode 42a: n × V1 ”. "<" Rated voltage "" is determined so that "n" and "V1" satisfy. Here, in the present embodiment, ten nickel-metal hydride storage batteries having a rated voltage of 1.2V are connected in series, so that the rated voltage of the assembled battery 3 is 12V. Therefore, in this embodiment, “n × V1” is set to be a value between “minimum discharge voltage: 10 V” and “rated voltage: 12 V” which is smaller than the maximum charge voltage of 16 V. When combining different types of light-emitting diodes, the light-emitting diodes of the same type are combined so that the sum of products obtained by multiplying the series number and the forward voltage of the light-emitting diode alone satisfies the above conditional expression. What is necessary is just to determine a kind and the number in series.

  Therefore, for example, as shown in FIG. 2, when the illumination 42 is made of light emitting diodes having a forward voltage of 1.9 V, the forward voltage of the assembled diode 42 a is set by setting the number of light emitting diodes in series to “6”. Is between the rated voltage of 12V, which is smaller than the maximum charging voltage of 16V, and the minimum discharging voltage of 10V, and is slightly higher than the minimum discharging voltage at which it can be determined that there is a possibility of becoming the minimum discharging voltage. It becomes a certain “1.9 × 6 = 11.4V”.

  That is, in this embodiment, according to the performance of the assembled battery 3, the number of series of light emitting diodes having a forward voltage of 1.9V is determined to be 6, and the assembled diode 42a is configured. As a result, when the remaining capacity of the assembled battery 3 that continues to be discharged due to the shortage of the generated power of the solar battery 1 decreases and the voltage drops to 11.4 V, the light emission of the assembled diode 42a gradually becomes weaker and then automatically. After the light emission is stopped and the voltage of the assembled battery 3 drops to 11.4 V, the power is automatically continuously supplied only to the environmental observation device 41, so that the operation period of the important load can be extended. it can.

  In addition, in this embodiment, the operating period of the important load can be increased by simply connecting the light emitting diodes in series without installing a voltage measuring device, a control circuit, and a switch such as an FET, which can increase the cost and the failure rate. Can be extended. Therefore, as described above, the power charged in the assembled battery 3 can be simply and efficiently provided to the load 4 including the illumination 42 according to the remaining capacity.

  Moreover, by installing the switch 5 with a timer, it is possible to supply electric power to the illumination 42 only at night, and the power saving effect realized by configuring the illumination with the assembled diode 42a in which light emitting diodes are connected in series. Can be further enhanced.

  In addition, although the present Example demonstrated the case where the important load which comprises the load 4 was the environment observation apparatus 41, this invention is not limited to this, For example, it is a case where it is a security camera etc. Alternatively, there may be a case in which there is no important load and the load 4 is configured only from the illumination 42.

  Here, when the load 4 is composed of only six assembled diodes 42a in which six light emitting diodes having a forward voltage of 1.9V are connected in series without an important load, the voltage of the assembled battery 3 decreases to 11.4V. Since the light emission of the assembled diode 42a is automatically stopped, the discharge from the assembled battery 3 is automatically stopped, and the overdischarge of the assembled battery 3 can be easily prevented.

  Furthermore, when the load 4 is composed only of the assembled diode 42a in which there is no important load and the light emitting diodes having a forward voltage of 1.9 V are connected in series, the charge amount of the assembled battery 3 can be used to a slightly lower voltage. That is, the minimum discharge voltage is a standard value that determines that the assembled battery 3 is deteriorated when the discharge is continued further. However, the deterioration does not occur immediately when the battery discharge voltage falls below the minimum discharge voltage. If it is up to “0.9V”, that is, up to “9V” in the assembled battery 3 to which 10 cells are connected, the possibility of deterioration is low even if discharging is continued. Therefore, as shown in FIG. 3, by setting the number of light emitting diodes in series to 5, the load 4 is close to 10 V that is the lowest discharge voltage (Vcut) of the assembled battery 3, and is 9.5 V slightly lower than 10 V. Until then, the electric power from the assembled battery 3 that continues to be discharged can be consumed. FIG. 3 is a diagram for explaining a modification.

  In the present embodiment, the case where the storage battery constituting the assembled battery 3 is a nickel metal hydride storage battery has been described, but the present invention is not limited to this, and the storage battery constituting the assembled battery 3 is, for example, It may be a case of a lead storage battery, a nickel cadmium storage battery, a lithium ion storage battery, or the like.

  Moreover, although the present Example demonstrated the case where the electric power used when the assembled battery 3 charges was supplied from the solar cell 1, this invention is not limited to this, For example, a power situation is very bad. It may be a case where power used when the assembled battery 3 is charged at a place is supplied from a DC power source such as an AC adapter or a primary battery.

  As described above, the power supply system according to the present invention is useful when a load including illumination operates using electric power supplied from a DC power supply or a storage battery, and in particular, a storage battery for a load including illumination. It is suitable for simply and efficiently providing the electric power charged in accordance with the remaining capacity.

It is a figure which shows the structure of the electric power supply system in a present Example. It is a figure for demonstrating the conditions for installing the illumination in a present Example. It is a figure for demonstrating a modification. It is a figure for demonstrating a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell 2 Converter 3 Assembly battery 4 Load 41 Environmental observation apparatus 42 Illumination 42a Assembly diode 42b Current limiting resistance 5 Switch with timer

Claims (4)

A power supply system comprising a storage battery that performs charging and discharging using power generated by a predetermined DC power supply, and a load including an illumination that operates using the power supplied from the predetermined DC power supply or the storage battery. There,
The illumination is a set diode in which one or more light emitting diodes are connected in series;
The series number of the light emitting diodes constituting the group diode is a value in which the forward voltage of the group diode is smaller than the maximum charge voltage of the storage battery and is within a predetermined range with respect to the minimum discharge voltage of the storage battery. A power supply system characterized by being defined as follows.   When the load is only illumination consisting of the group diode, the series number of the light emitting diodes constituting the group diode is such that the forward voltage of the group diode is close to the lowest discharge voltage of the storage battery. The power supply system according to claim 1, wherein the power supply system is defined as follows.   3. The power according to claim 1, further comprising power supply control means for controlling power supply from the predetermined DC power source or the storage battery to the assembled diode only within a predetermined time. Supply system.   The power supply system according to any one of claims 1 to 3, wherein the predetermined DC power source is a solar cell that generates power by sunlight.

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