KR20130095874A - Apparatus and method for controlling energy supply with sensor node - Google Patents

Abstract

PURPOSE: A power supply control apparatus and method of a sensor node periodically charge/discharge a capacitor according to active or slip mode, implementing stable power supply. CONSTITUTION: A solar cell unit changes solar energy to electric power. A sensor node (50) determines in a microprocessor active mode or sleep mode. The sensor node delivers a status signal of the modes to a relay circuit unit. A relay circuit unit (30) switches one power supply to the sensor node. A capacitor unit (40) selectively supplies charged voltage to the sensor node. [Reference numerals] (10) Solar cell unit; (20) Rechargeable battery; (30) Relay circuit unit; (40) Capacitor unit; (50) Sensor node; (60) Microprocessor

Description

Apparatus and Method for Controlling Energy Supply with Sensor Node}

The present invention relates to an apparatus and method for controlling power supply of a sensor node, and more particularly, to a sensor node in consideration of an active mode and a sleep mode of a solar cell operation mode and a sensor medium access control (MAC) protocol. The present invention relates to a power supply control device and method of a sensor node for efficiently managing the energy of a sensor node.

Ubiquitous Sensor Network (USN) detects / stores / processes / integrates objects and environmental information from tags and sensor nodes attached anywhere, and generates context-aware information and knowledge contents to provide customized knowledge services anytime, anywhere, and anywhere. It means the infrastructure of high-tech intelligent society that can be used. Here, ubiquitous is derived from Latin and means that it exists anytime, anywhere, and at the same time, and is a network in which the future society is invisible to all things and people inherent in the surrounding environment, such as water or air. It is used to mean that information can be obtained without being constrained by time and space. In addition, a sensor network refers to a wired / wireless communication technology based network formed between sensor nodes so that information sensed from the surrounding environment and the physical system is utilized in human life. USN is a sensor node, a sink node, a gateway, and a USN network. It is composed.

Due to the technological development of the USN, the application of such technology to military, science, public works, and industrial sites has been gradually expanded. However, since the power supply of the sensor node is limited, many difficulties have been encountered in making the USN practical. In particular, the problem of supplying and managing the power of sensor nodes installed outside the building or on top of large machines and equipment is not simple. That is, the wiring work is difficult and the battery needs to be replaced periodically. In order to overcome this problem, various studies are needed at the physical layer, MAC layer, and network layer in order to efficiently manage energy of a sensor node or sensor network. Energy harvesting requires an energy harvesting element. Currently, a variety of power supply devices such as solar cells, temperature changes and piezos are available. Among them, research is being actively conducted to apply solar cells that convert solar energy into electrical energy to USN. Cells can generate power with a certain amount of sunlight and are well suited for sensor nodes that can operate with less power.

As an example, a device for generating power using a solar cell includes a device for generating power using only a solar cell and a rechargeable battery. Such a device makes the sensor node operate stably by connecting the rechargeable battery and the sensor node in parallel. However, connecting the rechargeable battery and the sensor node in parallel requires a lot of current.

There are also devices that produce power using solar cells and capacitors. Since the device uses only a capacitor as a power supply for the sensor node, the sensor node stops working during a cloudy day or a night time.

There are also devices that produce power using solar cells, PVDFs, rechargeable batteries, and capacitors. These devices increase charging efficiency by using polyvinylidene fluoride (PVDF) and solar cells at the same time, but they are not only expensive, but they also use two power supply elements except in places where sunlight is not permanently absorbed at all. There is no advantage obtained by using.

Korean Patent Publication No. 10-1008202 (2011.01.07), a transformer that provides the effect of minimizing power consumption by maintaining the power consumption in the sleep mode, which is the minimum power consumption state in order to monitor the photovoltaic device A photovoltaic device monitoring system and a monitoring method are disclosed.

However, such a conventional photovoltaic device monitoring system and monitoring method have a problem in that the power supply and the power consumption of the solar cell and the active mode and the sleep mode of the sensor MAC protocol cannot be effectively switched.

Republic of Korea Patent Publication No. 10-1008202 (2011.01.07)

The present invention is to overcome the problems of the prior art described above, taking into consideration the power supply amount of the solar cell and the active mode and sleep mode of the sensor MAC protocol, the power supply control of the sensor node to switch the power supply and control the power consumption effectively Its purpose is to provide an apparatus and method.

In addition, the purpose is to supply a stable power by periodically charging and discharging the low-capacitance capacitor in accordance with the active / sleep mode.

In addition, the object of the present invention is to enable a sensor node to operate using a rechargeable battery even in the absence of a solar cell power supply.

The present invention to achieve the above object, the solar cell unit for converting solar energy into electrical energy; A rechargeable battery unit and a capacitor unit charged with electric energy from the solar cell unit; A sensor node which determines an active mode or a sleep mode in the microprocessor and transmits each state signal to the relay circuit; A relay circuit unit configured to determine one power supply source selected from the solar cell unit, the rechargeable battery unit, or the capacitor unit according to the output voltage of the solar cell unit and the state of the sensor node (Sleep / Active) signal and switch to the sensor node; And a capacitor unit that is charged by the solar cell unit and selectively supplies the charged voltage to the sensor node.

The relay circuit unit; When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the active mode, the output of the solar cell unit may be supplied to the sensor node and the capacitor unit may be charged.

The relay circuit unit; When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the sleep mode, the output voltage of the solar cell unit is supplied to the rechargeable battery unit and charged, and the voltage charged in the capacitor unit is It can be supplied to the sensor node.

The relay circuit unit; When the output voltage of the solar cell unit is less than the reference voltage and the state signal of the sensor node is the active mode, the voltage charged in the rechargeable battery unit may be charged to the capacitor and supplied to the sensor node.

The relay circuit unit; When the output voltage of the solar cell unit is less than the reference voltage and the state signal of the sensor node is in the sleep mode, the voltage charged in the capacitor may be supplied to the sensor node.

The capacitor unit; When the discharge voltage in the sleep mode falls below a reference value, the discharge mode may be converted to the active mode and recharged.

The method for controlling power supply of a sensor node according to the present invention includes converting solar energy into electrical energy in a solar cell unit; Receiving electrical energy from the solar cell unit to charge a rechargeable battery unit and a capacitor unit; Determining an active mode or a sleep mode in the microprocessor of the sensor node and transmitting each state signal to the relay circuit; Determining, by a relay circuit unit, a power supply source selected from the solar cell unit or the rechargeable battery unit according to an output voltage of the solar cell unit and a state signal of the sensor node and switching to the sensor node; Charging the capacitor unit by the solar cell unit, and selectively supplying a voltage charged in the capacitor unit to the sensor node.

The switching step; When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the active mode, the output of the solar cell unit may be supplied to the sensor node and the capacitor unit may be charged.

The switching step; When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the sleep mode, the output voltage of the solar cell unit is supplied to the rechargeable battery unit and charged, and the voltage charged in the capacitor unit is It can be supplied to the sensor node.

The switching step; When the output voltage of the solar cell unit is less than the reference voltage and the state signal of the sensor node is the active mode, the voltage charged in the rechargeable battery unit may be charged to the capacitor and supplied to the sensor node.

The switching step; When the output voltage of the solar cell unit is less than the reference voltage and the state signal of the sensor node is in the sleep mode, the voltage charged in the capacitor may be supplied to the sensor node.

Selectively supplying a voltage charged in the capacitor unit to the sensor node; When the discharge voltage in the sleep mode falls below a reference value, the discharge mode may be converted to the active mode and recharged.

According to the apparatus and method for controlling power supply of a sensor node according to the present invention configured as described above, it is possible to effectively switch power and control power consumption in consideration of the power supply amount of the solar cell and the active mode and the sleep mode of the sensor MAC protocol. It has an effect.

In addition, the low-capacitance capacitor can be charged and discharged periodically according to the active / sleep mode, thereby providing stable power and preventing the microprocessor from being reset even while switching the input power.

In addition, there is an effect that can operate the sensor node stably using a rechargeable battery even in the absence of a solar cell power supply.

1 is a view showing the operating environment of the sensor network model for implementing the present invention.
Figure 2 is a block diagram showing a power supply control device of the sensor node according to an embodiment of the present invention.
3 is a block diagram illustrating an operating state when the output voltage of the cell is equal to or greater than the reference voltage and the sensor node is in the active mode.
4 is a block diagram illustrating an operating state when the output voltage of the cell is equal to or greater than the reference voltage and the sensor node is in the sleep mode.
5 is a block diagram illustrating an operation state when the output voltage of the solar cell is less than the reference voltage and the sensor node is in the active mode.
6 is a block diagram illustrating an operating state when the output voltage of the cell is less than the reference voltage and the sensor node is in the sleep mode.
7 is a detailed circuit diagram illustrating a preferred embodiment of the block diagram of FIG. 2.
8A and 8B are graphs showing a relay operation pattern.
9 is a graph showing capacitor charge and discharge waveforms according to active / sleep mode switching.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the operating environment of a general sensor network model for implementing the present invention.

In general, the sensor network is composed of one server (sink node) (S) and a plurality of sensor nodes (sensor node) (1 ~ 9). Since the communication distance of sensor node is limited to reduce power consumption, multi-hop communication is performed.

As shown in FIG. 1, the sensor network naturally forms a tree having the sink node S as the root node. Each sensor node 1 to 9 periodically generates data and transmits the data to the sink node S along a path.

The sink node S uses a commercial power source, but the sensor nodes 1 through 9 use batteries, and thus disappear when the power is exhausted. Here, the sensor MAC protocol repeatedly performs a long sleep mode and a short active mode in order to reduce power consumption of the sensor node.

According to the change of the communication mode of the sensor MAC protocol, the power control module of the sensor node supplies the minimum power for maintaining the status information of the sensor node in the sleep mode, and normally the power in the active mode.

During 24 hours a day, the amount of illuminance supplied to a specific sensor node varies continuously with time and place. The amount of sunlight in the morning and afternoon is different, there are many places in the morning and many places in the afternoon. There is no sunlight on cloudy days and nights. Depending on the installation position of the sensor node, some sensor nodes have sufficient illumination to be driven using the solar cell's production power, and some nodes have insufficient illumination.

Some nodes may not be able to drive the sensor node only by supplying power through the solar cell in a situation where the illuminance is ambiguous. Depending on the operating state of the sensor node, some nodes may be in an active state requiring high operating power and some nodes may be in a sleep state using minimal power. Therefore, the input power supplying power to the sensor node should vary according to the illuminance and the operating state of the sensor node.

1, nodes 1 and 2 are in a state where the illumination intensity is sufficient. However, Node 1 requires low power because it is operating in a sleep state. The solar power produced during this time requires a rechargeable battery to be able to charge and use later.

Capacitors can be used to provide the low power required during the sleep time. For Node 2, the solar cell is powered because it is active and there is enough sunlight. Thus, the sensor node can be powered up while simultaneously charging the capacitor for use during the next sleep mode.

Node 4 in the active state and node 5 in the sleep state have insufficient illumination, and thus power can be supplied using a rechargeable battery charged when the illumination is sufficient. On the other hand, if you are active, such as Node 3, and the light intensity is unstable (cloudy weather where the light intensity is constantly changing), you can switch the solar cell power and the rechargeable battery power according to the situation.

As described above, in order to effectively use the solar cell according to the illumination intensity and the operation mode of the sensor MAC protocol, an element such as a solar cell, a rechargeable battery, and a capacitor is required, and a control circuit capable of controlling it according to a situation is required.

2 is a block diagram showing a power supply control device of a sensor node according to an embodiment of the present invention.

As shown, according to a preferred embodiment of the power supply control device of the sensor node according to the present invention, the solar cell unit 10 for converting solar energy into electrical energy, the electrical energy supplied from the solar cell unit 10 The sensor node which determines the active mode or the sleep mode in the rechargeable battery unit 20, the capacitor unit 40, and the microprocessor 60 to be charged and transmits each state signal to the relay circuit unit 30. 50 is selected from the solar cell unit 10 or the rechargeable battery unit 20 according to an output voltage of the solar cell unit 10 and a sleep / active signal of the sensor node 50. A capacitor for determining any one power supply source and being charged by the relay circuit unit 30 switching the sensor node 50, the solar cell unit 10, and selectively supplying the charged voltage to the sensor node 50. A portion 40 is included.

In addition, according to a preferred embodiment of the power supply control method of the sensor node according to the present invention, the solar cell unit 10 to convert the solar energy into electrical energy; Receiving electrical energy from the solar cell unit 10 to charge the rechargeable battery unit 20 and the capacitor unit 40; Determining an active mode or a sleep mode in the microprocessor 60 of the sensor node 50 and transmitting each status signal to the relay circuit unit 30; Any one selected from the solar cell unit 10 or the rechargeable battery unit 20 according to the output voltage of the solar cell unit 10 and the sleep / active signal of the sensor node 50 in the relay circuit unit 30. Determining a power supply source for the switching to the sensor node (50); Charging the capacitor unit 40 by the solar cell unit 10, and selectively supplying the voltage charged in the capacitor unit 40 to the sensor node 50.

The solar cell unit 10 may be formed of a conventional solar cell (also referred to as a solar cell) in order to convert solar energy into electrical energy. Although a pn junction device mainly made of single crystal silicon is used, it may be composed of polycrystalline silicon and amorphous silicon for the purpose of cost reduction.

The sensor node 50 includes a microprocessor 60 and a wireless transmit / receive chip (not shown). The microprocessor 60 may be a CPU or MPU having ordinary operations, processing, and judgment functions.

3 is a block diagram illustrating an operating state when the output voltage of the solar cell is equal to or greater than the reference voltage and the sensor node is in the active mode.

As shown, according to a preferred embodiment of the present invention, the solar cell unit 10 supplies power to the rechargeable battery unit 20, the capacitor unit 40, the sensor node 50 when the sunlight is sufficient.

The relay circuit unit 30 determines the flow of current according to the output voltage of the solar cell unit 10 and the sleep / active signal of the sensor node 50.

The sensor node 50 sends a high signal in the active mode and a low signal in the sleep mode to properly switch the power supply. .

That is, as shown, the relay circuit section 30; When the output voltage of the solar cell unit 10 is greater than or equal to the reference voltage and the state signal of the sensor node 50 is in the active mode, the output voltage of the solar cell unit 10 is supplied to the sensor node 50 and at the same time. The capacitor unit 40 is charged.

Since the output voltage of the solar cell unit 10 is used as it is in the active mode with a large amount of power consumption, there is no shortage of power, and at the same time, the capacitor unit 40 can be charged with power. The capacitor unit 40 may be a small capacitor of about 1,000 to 3,300 uF, and may be buffered with a time of about 1 second or less in a typical active mode as shown in FIG. 9.

4 is a block diagram illustrating an operating state when the output voltage of the solar cell is equal to or greater than the reference voltage and the sensor node is in the sleep mode.

As shown, according to a preferred embodiment of the present invention, the relay circuit section 30; When the output voltage of the solar cell unit 10 is greater than or equal to the reference voltage and the state signal of the sensor node 50 is in the sleep mode, the output voltage of the solar cell unit 10 is supplied to the rechargeable battery unit 20. The battery is charged, and the voltage charged in the capacitor unit 40 is supplied to the sensor node 50.

Therefore, in the sleep mode state in which the power consumption is low, the power charged in the capacitor unit 40 is supplied to the sensor node 50. According to a preferred embodiment of the present invention, the capacitor unit 40 may be a small capacity capacitor of about 1,000 to 3,300 uF, and may be buffered with a time of 1 second or less in a normal active mode as shown in FIG. 9. Can be discharged in a sleep mode in a time of approximately 2-4 seconds.

Therefore, before the capacitor unit 40 is discharged in the sleep mode, the capacitor unit 40 may be recharged with the power of the solar cell unit 10 by switching to the active mode shown in FIG. 3. This can be done quickly and repeatedly.

FIG. 5 is a block diagram illustrating an operating state when the output voltage of the solar cell is less than the reference voltage and the sensor node is in the active mode.

As shown, according to a preferred embodiment of the present invention, the relay circuit section 30; When the output voltage of the solar cell unit 10 is less than the reference voltage and the state signal of the sensor node 50 is the active mode, the capacitor unit 40 charges the voltage charged in the rechargeable battery unit 20. At the same time it is supplied to the sensor node (50).

As shown in FIG. 4, the rechargeable battery unit 20 is sufficiently charged in the state in which the output voltage of the solar cell is equal to or higher than the reference voltage and the sensor node is in the sleep mode, so that the rechargeable battery unit 20 is supplied to the sensor node 50. There is no shortage of power.

At the same time, the electric power can be charged to the capacitor unit 40. As described above, the capacitor unit 40 is a small-capacity capacitor and can be buffered for a time of about 1 second or less in a normal active mode.

6 is a block diagram illustrating an operating state when the output voltage of the solar cell is less than the reference voltage and the sensor node is in the sleep mode.

As shown, according to a preferred embodiment of the present invention, the relay circuit section 30; When the output voltage of the solar cell unit 10 is less than the reference voltage and the state signal of the sensor node 50 is in the sleep mode, the voltage charged in the capacitor unit 40 is supplied to the sensor node 50. .

Therefore, in the sleep mode state where the power consumption is low, the power charged in the capacitor unit 40 may be supplied to the sensor node 50. As described above, according to the preferred embodiment of the present invention, the capacitor unit 40 A small capacitor may be used, and as shown in FIG. 9, a small capacitor may be discharged at a time of about 2 to 4 seconds in a normal sleep mode, and may supply power to the sensor node 50.

In this case, before the capacitor unit 40 is discharged in the sleep mode, the capacitor unit 40 may be recharged by the power of the rechargeable battery unit 20 by switching to the active mode shown in FIG. 5. This can be done in quick time.

FIG. 7 is a detailed circuit diagram illustrating a preferred embodiment of the block diagram of FIG. 2.

Terms used in FIG. 7 are defined as shown in Table 1 below.

The operation of the circuit according to the presence of sunlight and the operation state of the sensor node is as follows.

end. If there is sunlight and the sensor node is in active mode

In this case, the output voltage Vsolar of the solar cell SC outputs a high voltage, and the output voltage Vcon of the sensor node SN outputs a high signal. Due to the high voltage of Vsolar, relay Relay2 is connected to switching out, and due to the high signal of Vcon, relay Relay1 is also connected to switching out. The output voltage Vsolar of the solar cell SC is supplied to the sensor node SN through the regulator REG and the relay relay 1 and simultaneously charges the capacitor C3.

I. If there is sunlight and the sensor node is in sleep mode

In this case, the output voltage Vsolar of the solar cell SC is a high voltage, and the output voltage Vcon of the sensor node SN outputs a low signal. Due to the high voltage of Vsolar, relay Relay2 is connected to switching out, and due to the low signal of Vcon, relay Relay1 is connected to base out. Vsolar charges the Recharging Battery (RB) via regulators REG, relays Relay1, Relay2, and the overcharge protection device PCM. At this time, the capacitor C3 charged during the active mode supplies the operating power of the sensor node SN.

All. If the weather is cloudy or night time

. In this case, the output voltage Vsolar of the solar cell SC outputs a low voltage. Due to the low voltage of Vsolar, relay Realy1 and Relay2 are connected to the base out, and the rechargeable battery (RB) supplies the operating power to the sensor node (SN) through the base out of the overcharge protection device PCM and relay Relay2. .

The sensor node SN basically synchronizes time with the neighbor sensor node SN. The sensor node SN having data to transmit wakes up at the set active mode time and transmits data to the neighboring sensor node SN that wakes up at the same time and is switched to the sleep mode at the next sleep mode start time.

In a preferred embodiment of the present invention, a circuit including a microprocessor (MCU) 60 and a radio transceiver chip (not shown) may be used. In order to operate the wireless transmit / receive chip at low power, the wireless transmit / receive chip with high power consumption is first put into sleep mode, and then the MCU is put into sleep mode. Among the four sleep modes of the MCU, LPM0 (CPU and MCLK Disabled, ACLK and SMCLK Active) was used. The power consumption was measured at 75uA and the time to wake-up was at least 6us. When the MCU enters sleep mode, the external connected components (ROM, sensors) are powered off. The transition to the active mode is the reverse of the sleep mode.

The solar cell (SC) outputs a DC voltage without a separate rectifier circuit, and can be used anywhere there is sunlight. However, during a cloudy day or night time, the sensor node SN cannot be operated because the output power of the solar cell is insignificant. In order to overcome this disadvantage, a rechargeable battery (RB) was used.

As shown in the block diagram of the present invention shown in Figures 2 to 6, according to a preferred embodiment of the present invention, the relay Relay1, Relay2 was used to switch the input power according to the presence of sunlight, the mode of the sensor node (SN). .

The typical characteristic of the 5V operating relay used in this circuit is the switching output when the voltage difference across 3.5V is 3.5V, and back to the base output when 1V is reached. However, in the case of the solar cell SC, when the output voltage is less than 4.5V, the 5V relay cannot be used as it is because power is not generated enough to drive the sensor node SN.

In order to solve this problem, according to the preferred embodiment of the present invention, when the MOSFET (MOS field-effect transistor) FET1 and FET2 are arranged in series in each of the relays Relay1 and Relay2, when the difference between the voltages at both ends of the relay Relay1 and Relay2 becomes 5V, Switching out, 4.5V was configured to switch to the base out.

8A and 8B are graphs showing the operation pattern of the relay, and show the experimental results of the operation pattern of the original relay and the operation of the changed relay to which the MOSFET is applied to the change of the supply voltage.

The curve waveform graph shows the voltage supplied to the relay, the pulse graph shows the state of the relay according to the input voltage, low is connected to the base output, and high is connected to the switching output. Means status.

Capacitor C3 supplies the operating power to the sensor node SN because the current draws low when the sensor node SN is in sleep mode, and power is supplied when the relay relays 1 and 2 switch the power supply source of the sensor node SN. It serves to prevent this break.

During the active mode time, the voltage across the regulator REG rapidly charges the capacitor C3 and discharges while powering the sensor node SN during the sleep mode time.

9 is a graph illustrating capacitor charge and discharge waveforms according to active / sleep mode switching. The amount of capacitor charged during the active time should be sufficient to power up during the sleep mode time. According to a preferred embodiment of the present invention, the capacitor may be a small capacity capacitor of about 1,000 to 3,300 uF, and may be buffered in a typical active mode for a time of 1 second or less, and in the sleep mode as shown. It is discharged in a time of 2 to 4 seconds.

In another preferred embodiment of the present invention, when the capacitor is discharged in the sleep mode, the capacitor may be recharged through a quick mode switch to the active mode. The mode switching timing sets a reference value of the discharge capacity according to the type of capacitor, monitors the discharge capacity value or the voltage value in real time, and switches the active mode and the sleep mode to easily recharge the capacitor before the capacitor is discharged. .

The embodiments of the present invention described in the present specification and the configurations shown in the drawings relate to the most preferred embodiments of the present invention and are not intended to encompass all of the technical ideas of the present invention so that various equivalents It should be understood that water and variations may be present. Therefore, it is to be understood that the present invention is not limited to the above-described embodiment, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. , Such changes shall be within the scope of the claims set forth in the claims.

10: Cell part
20: rechargeable battery unit
30: relay circuit
40: capacitor
50: sensor node
60: microprocessor

Claims (12)

A solar cell unit converting solar energy into electrical energy;
A rechargeable battery unit and a capacitor unit charged with electric energy from the solar cell unit;
A sensor node which determines an active mode or a sleep mode in the microprocessor and transmits each state signal to the relay circuit;
A relay circuit unit configured to determine one power supply source selected from the solar cell unit or the rechargeable battery unit and switch to the sensor node according to an output voltage of the solar cell unit and a status (Sleep / Active) signal of the sensor node; And
And a capacitor unit charged by the solar cell unit and selectively supplying the charged voltage to the sensor node.
The method of claim 1,
The relay circuit unit;
When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the active mode, the output of the solar cell unit to the sensor node and at the same time charging the capacitor unit of the sensor node Power supply controller.
The method of claim 1,
The relay circuit unit;
When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the sleep mode, the output voltage of the solar cell unit is supplied to the rechargeable battery unit and charged, and the voltage charged in the capacitor unit is Power supply control device for a sensor node, characterized in that the supply to the sensor node.
The method of claim 1,
The relay circuit unit;
When the output voltage of the solar cell unit is less than the reference voltage and the state signal of the sensor node is the active mode, the voltage charged in the rechargeable battery unit is charged to the capacitor and supplied to the sensor node at the same time Sensor supply power supply control device.
The method of claim 1,
The relay circuit unit;
And supplying a voltage charged in the capacitor to the sensor node when the output voltage of the solar cell unit is less than a reference voltage and the state signal of the sensor node is in the sleep mode.
6. The method according to any one of claims 1 to 5,
The capacitor unit; And when the discharge voltage in the sleep mode falls below a reference value, the power supply controller of the sensor node, wherein the sensor node is switched to the active mode and recharged.
Converting solar energy into electrical energy in the solar cell unit;
Receiving electrical energy from the solar cell unit to charge a rechargeable battery unit and a capacitor unit;
Determining an active mode or a sleep mode in the microprocessor of the sensor node and transmitting each state signal to the relay circuit;
Determining, by a relay circuit unit, a power supply source selected from the solar cell unit or the rechargeable battery unit according to an output voltage of the solar cell unit and a state signal of the sensor node and switching to the sensor node; And
And charging the capacitor unit by the solar cell unit, and selectively supplying a voltage charged in the capacitor unit to the sensor node.
8. The method of claim 7,
The switching step;
When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the active mode, the output of the solar cell unit to the sensor node and at the same time charging the capacitor unit of the sensor node Power supply control method.
8. The method of claim 7,
The switching step;
When the output voltage of the solar cell unit is greater than or equal to the reference voltage and the state signal of the sensor node is in the sleep mode, the output voltage of the solar cell unit is supplied to the rechargeable battery unit and charged, and the voltage charged in the capacitor unit is Power supply control method for a sensor node, characterized in that the supply to the sensor node.
8. The method of claim 7,
The switching step;
When the output voltage of the solar cell unit is less than the reference voltage and the state signal of the sensor node is the active mode, the voltage charged in the rechargeable battery unit is charged to the capacitor and supplied to the sensor node at the same time How to control power supply of sensor node.
8. The method of claim 7,
The switching step;
And supplying a voltage charged to the capacitor to the sensor node when the output voltage of the solar cell unit is less than a reference voltage and the state signal of the sensor node is in the sleep mode.
The method according to any one of claims 7 to 11,
Selectively supplying a voltage charged in the capacitor unit to the sensor node;
And when the discharge voltage in the sleep mode falls below a reference value, switching to the active mode to recharge the sensor node.

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