CN101086523A

CN101086523A - Sensor node energy management system

Info

Publication number: CN101086523A
Application number: CNA2007101177969A
Authority: CN
Inventors: 苏波; 李艳秋; 于红云; 尚永红
Original assignee: Institute of Electrical Engineering of CAS
Current assignee: Institute of Electrical Engineering of CAS
Priority date: 2007-06-25
Filing date: 2007-06-25
Publication date: 2007-12-12

Abstract

A sensor knot energy management system comprises the switch circuit, charge circuit, stabilizing circuit, voltage rising circuit, single chip and A/D converter circuit. Energy of the output energy provides electricity to sensor knot, single chip and A/D converter circuit through the charge circuit, stabilizing circuit, through voltage rising charging the super capacitor directly. Single chip circuit controls the A/D converter timely inspects super capacitor both ends of the voltage. When the voltage resistance value is 2.7v, equal to the super capacitor, turns on the switch circuit of the single chip, charging with the super capacitor coupling with the lithium battery. It can realize intelligent management of energy, extends the using durability of the sensor knot, solving the energy bottle neck issue of the sensor network.

Description

A kind of sensor node energy management system

Technical field

The present invention relates to a kind of energy management system for the sensor node power supply.

Background technology

The application prospect of sensor network is boundless, can be widely used between military affairs, environmental monitoring and forecast, buildings condition monitoring, complicated machinery monitoring, urban transportation, space exploration, large car and storehouse management, and the fields such as safety monitoring in airport, large scale industry garden, large tracts of land farmland.

The sensor node volume is small, can only carry the very limited battery of energy.Some environmental monitoring application need carries out the monitoring of continuous several months, and this energy supply to sensor node has proposed very high requirement.Present sensor node uses two joint dry cell power supplies mostly, and such electric power approximately is 2200mAh under the 3V situation.Continuous firing is 9 months if desired, and each node has only the electric weight of 8.15mAh average every day.So, sensor node can be worked long hours, can only adopt the energy-saving type way to manage by the self-contained finite energy of sensor node.When node does not have the sensing task at present and do not need for other node forwarding sensing datas, the wireless communication module of closed node, data acquisition module even computing module are to save energy, like this, when a sensing task takes place, have only the sensor node in the adjacent areas with it to be in active state, thereby form a zone of action.The zone of action is saved energy along with data transmit and move to gateway node thereby the node of so original activity can forward park mode to after leaving the zone of action.In addition, in a sensor network, different nodes also have different to the demand of energy with use.For example, the node of close base station may need more energy to be used in to be transmitted on the packet, and the node of network edge can be used in main energy on the collection sensing data.Therefore, some node consumed energy is than very fast, even adopt power save mode can not solve the energy problem of whole sensor network effectively.

Having adopted solar-energy photo-voltaic cell to absorb energy as the energy from environment in the Chinese patent 200610114706.6 is the sensor node power supply, solved the problem that sensor node can not work long hours from charged pool, but existed not enough the concrete management of energy and the design of circuit.Chinese patent 200610114708.5 utilizes heat conductive silica gel to stick on the back of solar-energy photo-voltaic cell thermoelectric cell, when utilizing solar-energy photo-voltaic cell work in back of the body temperature and the environment temperature difference between the temperature generate electricity, this has further utilized the energy in the environment.But the energy management circuit of this patent partly exists circuit complexity, shortcoming that efficient is lower.

Summary of the invention

The objective of the invention is to overcome prior art circuits complexity, shortcoming that efficient is lower, provide a kind of efficient and rational intelligent degree high energy management system.The present invention adopts solar-energy photo-voltaic cell and thermoelectric cell as giving birth to the energy device, and lithium ion battery and ultracapacitor are as energy storage device, for sensing plays the node power supply.Can intelligent effectively management solar-energy photo-voltaic cell and thermoelectric cell form twin can system, and the energy in the double-energy storage system that forms of lithium ion battery and ultracapacitor.

The periphery of energy management system of the present invention by solar-energy photo-voltaic cell and thermoelectric cell form twin can system, form by double-energy storage system and sensor node that lithium ion battery and ultracapacitor are formed.Energy management system mainly is made up of switch switching circuit, charging circuit, mu balanced circuit, booster circuit, single-chip microcomputer and A/D change-over circuit.

Solar-energy photo-voltaic cell directly changes into electric energy with solar radiant energy, by being lithium ion cell charging by charging circuit and mu balanced circuit respectively behind the diode and being sensor node, single-chip microcomputer and A/D converter power supply.Charging circuit is a core with charging chip max866, and the periphery is furnished with charging indicator light and filter capacitor, and during to lithium ion cell charging, light emitting diode lamp is lighted at solar-energy photo-voltaic cell.Mu balanced circuit only is made up of voltage stabilizing chip max8881, and the constant voltage of 3.3V can be provided for sensor node.

Thermoelectric cell is attached to the back side of solar-energy photo-voltaic cell by heat conductive silica gel, utilize the thermo-electric generation of solar-energy photo-voltaic cell back of the body temperature and environment, because the voltage of thermoelectric cell output is lower, can not directly charge to ultracapacitor, so be connected a booster circuit between thermoelectric cell and ultracapacitor, the main chip of booster circuit is max866, it can be raised to 5V with the voltage of 0.9V, the peripheral inductance of chip of boosting is 330uH, and the correctness of this numerical value directly has influence on the effect of boosting.

The core of energy management system is the AT89C2051-12PU single-chip microcomputer, and its control A/D converter and on-off circuit carry out operate as normal.Single-chip microcomputer and A/D converter all are can be at the device of 3-5V work, for the stable operation of system provides guarantee.A/D converter regularly detects the voltage at ultracapacitor two ends, if voltage equals the withstand voltage 2.7V of ultracapacitor, single-chip microcomputer is opened switch switching circuit, makes ultracapacitor begin discharge.Because the withstand voltage 2.7V of ultracapacitor is less than the cut-off voltage 3V of lithium ion battery, so ultracapacitor has also used booster circuit in discharge process, the booster circuit of this booster circuit and thermoelectric cell is identical.The electric weight of ultracapacitor output is a lithium ion cell charging by charging circuit behind booster circuit.The ultracapacitor discharge utilizes the method for time-delay, and delay time is by repeatedly experiment acquisition, and delay time finishes, and single-chip microcomputer cut-off switch circuit is powered by thermoelectric cell again.

When solar-energy photo-voltaic cell and thermoelectric cell cisco unity malfunction (such as evening), lithium ion battery will be powered for sensor node, and keep the normal operation of single-chip microcomputer and A/D converter.

Description of drawings

Fig. 1 is that the little energy of mixing that solar-energy photo-voltaic cell and thermoelectric cell are formed is the overall schematic of sensor node energy supply;

Fig. 2 is the energy management system circuit diagram;

Among the figure: 1. switch switching circuit, 2. charging circuit, 3. mu balanced circuit, 4. booster circuit, 5. booster circuit, 6. single-chip microcomputer and A/D change-over circuit.

Embodiment

Energy management system provided by the invention and peripheral components are as shown in Figure 1.Energy management system stores in lithium ion battery and the ultracapacitor as the energy of core component with solar-energy photo-voltaic cell and thermoelectric cell generation, and the energy of intelligently allocating in each energy storage device is the sensor node power supply.

Energy management system of the present invention mainly is made up of switch switching circuit 1, charging circuit 2, mu balanced circuit 3,

booster circuit

4 and 5, single-chip microcomputer and A/D change-over circuit 6.The electric energy of solar-energy photo-voltaic cell output is powered to lithium ion cell charging with to sensor node, single-chip microcomputer U6, A/D converter U7 respectively by charging circuit 2 and mu balanced circuit 3, and the electric energy of thermoelectric cell output is powered to ultracapacitor by booster circuit 4 backs; When the voltage that detects the ultracapacitor two ends as A/D converter U7 equals its withstand voltage 2.7V, single-chip microcomputer U6 just connects the following relay of switch chip U1, the last relay of while off switch chip U1, make the electric weight in the ultracapacitor in parallel with solar-energy photo-voltaic cell to lithium ion cell charging through booster circuit 5 backs, its circuit structure as shown in Figure 2.

The peripheral components of energy management system: solar-energy photo-voltaic cell, thermoelectric cell, lithium ion battery, ultracapacitor and sensor node are connected with the pairing interface of energy management system respectively: the solar-energy photo-voltaic cell interface is the input end of charging circuit 2, the solar-energy photo-voltaic cell interface is by diode D1, input end with charging chip U2 MAX1811 behind the D4 is connected, the output terminal of charging chip U2 and lithium ion battery interface, single-chip microcomputer U6 in single-chip microcomputer and the A/D change-over

circuit

6,8 pins of U1 are connected in the power end Vcc of A/D converter U7 and the switch switching circuit 1.Charging chip U2 is furnished with the periphery charging indicator light D2 and divider resistance R2, and during the charging circuit operate as normal, charging indicator light D2 is luminous.The input end of mu balanced circuit links to each other with 7 pins of U1 in the switch switching circuit 1 with solar-energy photo-voltaic cell respectively; mu balanced circuit 3 mainly is made up of voltage stabilizing chip U3 MAX8881; peripheral resistance R 3 is a protective resistance, and the output terminal of mu balanced circuit 3 is connected with sensor node.The thermoelectric cell interface is the input end of booster circuit 4, and the core devices of booster circuit 4 is the chip U4 MAX866 that boost, and its peripheral inductance L 1 value is 300uH.Boost chip U4 output terminal by diode D6 respectively with ultracapacitor, switch switching circuit 1 in controlled terminal 5 pin of switch chip U1 and single-chip microcomputer and the A/D change-over circuit 6 input pin 2 of A/D converter U7 link to each other.Controlled terminal 6 pin of switch chip U1 link to each other with the input end of booster circuit 5, and booster circuit 5 is identical with the structure of booster circuit 4.The 14th pin of single-chip microcomputer U6 links to each other 2, the 4 pin ground connection of switch chip U1 with

control end

1,3 pins of switch chip U1 in the switch switching circuit 1 respectively with 15 pins in single-chip microcomputer and the A/D change-over circuit 6.

Charging circuit 2 adopts has the few max1811 chip of high charging precision, peripheral components; Mu balanced circuit 3 adopts the max8881 chip of small size, little power consumption; Booster circuit 4 adopt high-level efficiency, can be at the max866 chip of 0.9V work; Single-chip microcomputer and A/D change-over circuit are made up of the AT89C2051-12PU single-chip microcomputer and the TLC549A/D converter of low-power consumption, low-voltage; What switch switching circuit adopted is the AQW212 chip highly sensitive, that corresponding speed is fast.

The electric energy of solar-energy photo-voltaic cell output is powered to sensor node by mu balanced circuit 3.If the solar-energy photo-voltaic cell output power is bigger, this moment also can be by charging circuit 2 to lithium ion cell charging, provide energy for single-chip microcomputer U6 and A/D converter U7 simultaneously, the energy shortage that provides when solar-energy photo-voltaic cell is when satisfying the required energy of node, and lithium ion battery will be powered to sensor node by mu balanced circuit 3.

Temperature in the solar-energy photo-voltaic cell when work back of the body benign environment has certain temperature difference, so be pasted with thermoelectric cell at the back side of solar-energy photo-voltaic cell, in order to keep the lasting existence of the temperature difference, is pasted with heat radiator at the another side of thermoelectric cell.Because the voltage of thermoelectric cell output is less, directly very unrealistic to the ultracapacitor charging, so between the output terminal of thermoelectric cell and ultracapacitor, increased booster circuit 4, can make and store more energy in the ultracapacitor.A/D converter U7 regularly detects the voltage at ultracapacitor two ends under the control of single-chip microcomputer U6, the voltage when the ultracapacitor two ends equals its withstand voltage 2.7V, and the switch chip U1 in the single-chip microcomputer U6 gauge tap commutation circuit 1 makes ultracapacitor begin discharge.Because the withstand voltage 2.7V of ultracapacitor voltage is less than the cut-off voltage value 3.0V of lithium ion battery, so also used booster circuit 5 in the process of ultracapacitor discharge.The input end of this booster circuit 5 links to each other with the output pin 6 of switch chip U1, links to each other with the input end of charging circuit 2 after the output terminal parallel connection of the output terminal of booster circuit 5 and solar-energy photo-voltaic cell.Because ultracapacitor has trickle charge and puts soon, so, electric weight can be emitted in a short period of time, be lithium ion cell charging.The discharge time of ultracapacitor is through repeatedly the experiment back is definite, specific implementation process adopts the method for software delay, delay time arrives, single-chip microcomputer is off switch chip U1 then, return to original state, be that solar-energy photo-voltaic cell is lithium ion cell charging and sensor node power supply by charging circuit 2 and mu balanced circuit 3 respectively, thermoelectric cell charges to ultracapacitor by booster circuit 4.That single-chip microcomputer U6 and A/D converter adopt is the AT89C2051-12PU and the TLC549 that can work under the 3V low-voltage, they can be directly by solar-energy photo-voltaic cell or lithium ion battery power supply, save extra booster circuit, improved the efficient of energy management system.

Claims

1, a kind of sensor node energy management system is characterized in that energy management system mainly is made up of switch switching circuit [1], charging circuit [2], mu balanced circuit [3], booster circuit [4,5], single-chip microcomputer and A/D change-over circuit [6]; The electric energy of solar-energy photo-voltaic cell output passes through to power to lithium ion cell charging with to single-chip microcomputer [U6], A/D converter [U7], sensor node respectively behind charging circuit [2] and the mu balanced circuit [3]; The electric energy of thermoelectric cell output is powered to ultracapacitor by booster circuit [4] back, when the voltage that detects the ultracapacitor two ends when A/D converter [U7] equals its withstand voltage 2.7V, [15] pin output high level of single-chip microcomputer [U6], connect the following relay of switch chip [U1], it is in parallel with solar-energy photo-voltaic cell to lithium ion cell charging through booster circuit [5] back that the last relay of [14] pin output low level off switch chip [U1] of single-chip microcomputer [U6] makes the electric weight in the ultracapacitor simultaneously; The input end of charging circuit [2] is the solar-energy photo-voltaic cell interface, the output terminal of the charging chip [U2] in the charging circuit [2] and lithium ion battery interface and single-chip microcomputer, A/D converter power end link to each other, the output terminal of mu balanced circuit [3] is connected with sensor node, the input end of booster circuit [4] is the thermoelectric cell interface, and the output terminal of the chip that boosts [U4] in the booster circuit [4] is connected with ultracapacitor by diode [D6]; Energy management system stores the energy of solar-energy photo-voltaic cell and thermoelectric cell generation respectively in lithium ion battery and the ultracapacitor, and the energy of intelligently allocating in each energy storage device is the sensor node power supply: solar-energy photo-voltaic cell is powered to lithium ion cell charging with to sensor node by charging circuit [2] and mu balanced circuit [3] respectively, and the electric energy that thermoelectric cell produces charges to ultracapacitor by booster circuit [4]; The energy shortage that provides when solar-energy photo-voltaic cell is powered to sensor node by mu balanced circuit [3] as power supply by lithium ion battery when satisfying the required energy of node.

2, according to the described sensor node energy management system of claim 1, it is characterized in that in the charging circuit [2], the solar-energy photo-voltaic cell interface is connected with the input end of charging chip [U2] MAX1811 by diode [D1], [D4] back, the output terminal of charging chip [U2] is connected with the power end Vcc of the middle single-chip microcomputer [U6] of lithium ion battery interface, single-chip microcomputer and A/D change-over circuit [6], A/D converter [U7], and charging chip [U2] periphery is furnished with charging indicator light [D2] and divider resistance [R2]; The solar-energy photo-voltaic cell interface is connected with the input end of mu balanced circuit [3] by diode [D1] back, mu balanced circuit [3] mainly is made up of voltage stabilizing chip [U3] MAX8881, peripheral resistance [R3] is protective resistance, and the output terminal of mu balanced circuit [3] links to each other with sensor node; The core devices of booster circuit [4] boost chip [U4] MAX866 output terminal by diode [D6] respectively with ultracapacitor, switch switching circuit [1] in controlled terminal [5] pin of switch chip [U1] and single-chip microcomputer and the A/D change-over circuit [6] input pin [2] of A/D converter [U7] link to each other, controlled [6] pin of switch chip [U1] links to each other with the input end of booster circuit [5], and controlled terminal [8] pin of switch chip [U1] is connected with diode [D3] with lithium ion battery respectively with [7] pin; Booster circuit [5] is identical with the structure of booster circuit [4]; [15] pin of single-chip microcomputer [U6] links to each other [2] pin of switch chip [U1] and [4] pin ground connection with control end [3] pin of the middle switch chip [U1] of switch switching circuit [1] respectively with [14] pin in single-chip microcomputer and the A/D change-over circuit [6] with [1] pin.

3, according to the described energy management system of claim 1, the voltage that it is characterized in that Single-chip Controlling A/D converter timing acquiring ultracapacitor two ends, reach the withstand voltage 2.7V of ultracapacitor when the voltage at ultracapacitor two ends, single-chip microcomputer [15] pin output high level is opened the following relay of on-off circuit [1], relay is closed in while [14] pin output low level pass makes the electric energy in the ultracapacitor in parallel with solar-energy photo-voltaic cell by another booster circuit [5], is lithium ion cell charging by charging circuit [2] then; Ultracapacitor has adopted the method for time-delay in discharge process, when delay time arrives, the single-chip microcomputer off switch circuit of giving an order, thermoelectric cell charges to ultracapacitor then, and solar-energy photo-voltaic cell is to lithium ion cell charging and be that sensor node, single-chip microcomputer and A/D converter are powered.