CN114285132A - A low-power energy harvesting circuit - Google Patents

Abstract

The invention belongs to the technical field of micro-energy collection circuits, in particular to a low-power-consumption energy collection circuit, which solves the technical problems in the background technology and comprises a first energy harvesting unit, a second energy harvesting unit, a first full-bridge rectification circuit, a first electronic switch device, a third electronic switch device, a second electronic switch device, a fourth electronic switch device, a first energy storage capacitor, a first voltage stabilizing circuit, electric equipment, a second full-bridge rectification circuit, a fifth electronic switch device, a seventh electronic switch device, a sixth electronic switch device, an eighth electronic switch device, a second energy storage capacitor, a second voltage stabilizing circuit, a third voltage stabilizing circuit and an energy storage battery; also comprises a monitoring and control circuit. The monitoring and control circuit controls the time duty ratio of the electronic switching device for supplying power to the load to be reduced to the minimum, the energy storage battery is charged in the rest time, the circuit loss is effectively reduced, the electric energy is efficiently utilized, the normal work of the load is guaranteed, and meanwhile, the standby battery can be charged and stored with energy.

Description

A low power consumption energy harvesting circuit

technical field

The invention belongs to the technical field of micro-energy collection circuits, in particular to a low-power consumption energy collection circuit.

Background technique

In today's era, a large number of intelligent wearable products have emerged. With the increase in the number of intelligent electronic products, the issue of power supply for intelligent products has become a concern. At present, in the process of outdoor activities and field adventures, the energy supply of electronic products is mostly realized by chemical batteries, and chemical batteries also present the problem of non-recyclability and environmental pollution. Few of them use solar power, but solar power is severely restricted by the external environment. In this regard, a mechanical energy with high energy density, wide distribution, diverse manifestations, not limited by time and space, and easy to convert is proposed to support the movement of the human body. However, the electric energy collection efficiency generated by the alternator driven by the human body motion transmission gear mechanism is low, and the power consumption of the electric energy collection circuit is large, resulting in a very small amount of electric energy storage. Therefore, how to efficiently collect these energies and how to minimize the power consumption of the circuits that collect these energies have become the key issues that must be solved in the collection of these energies.

SUMMARY OF THE INVENTION

The invention aims to solve the technical problems of how to efficiently collect energy generated by human body operation and how to minimize the power consumption of the circuit for collecting these energy sources, and provides a low-power consumption energy collection circuit. By monitoring the load and controlling the power supply of the power generation unit to the load and the battery charging on and off, the power consumption of the circuit is reduced to the maximum extent, and the high-efficiency utilization of the power of the power generation unit is greatly improved.

The technical means adopted by the present invention to solve the technical problems are: a low-power consumption energy collection circuit, comprising a first energy capture unit and a second energy capture unit, and the output end of the first energy capture unit is connected with a first full-bridge rectifier circuit , the output end of the first full-bridge rectifier circuit is respectively connected with the first electronic switching device and the third electronic switching device in two ways, and the output end of the first electronic switching device is connected in two ways with the second electronic switching device and the fourth electronic switching device A switching device, the output end of the second electronic switching device is sequentially connected to the electrode end of the electrical equipment through the first energy storage capacitor and the first voltage stabilizer circuit; the output end of the second energy capture unit is connected with a second full-bridge rectifier circuit, The output end of the second full-bridge rectifier circuit is connected with the fifth electronic switching device and the seventh electronic switching device respectively in two ways, and the output end of the seventh electronic switching device is connected with the sixth electronic switching device and the eighth electronic switch in two ways device, the output end of the eighth electronic switching device is sequentially connected to the other end of the electrode of the electrical equipment through the second energy storage capacitor and the second voltage stabilizing circuit; the third electronic switching device, the fifth electronic switching device, and the fourth electronic switching device A third voltage-stabilizing circuit is connected in parallel with the output end of the sixth electronic switching device, and an energy storage battery is connected to the output end of the third voltage-stabilizing circuit; it also includes a device for collecting real-time power of electrical equipment and real-time power through electrical equipment. A monitoring and control circuit that controls the on-off time of each electronic switching device.

In the collection circuit of the present invention, the first energy capture unit and the second energy capture unit are responsible for converting mechanical energy such as vibration and noise in the environment into electrical energy, and floating energy from the environment to supply power for subsequent circuits. The structure of the unit and the second energy harvesting unit is designed to combine the characteristics of the reciprocation of human motion, so the electric energy collected by the energy harvesting unit is unidirectional pulsed power supply. The full-bridge rectifier circuit is responsible for converting the three-phase AC power output by the energy capture unit into DC power; each electronic switching device is responsible for controlling the on-off of the power supply circuit to the load or the energy storage battery; each voltage regulator circuit is responsible for converting the DC power converted by the rectifier circuit into DC power Convert to the appropriate voltage required by the load. The monitoring and control circuit controls each electronic switching device to control to ensure that the load works normally under the lowest current state. When the human body moves, the mechanical energy generated by each body part can be converted into electric energy, and the generated electric energy can finally realize the function of supplying power to the smart wearable or charging the energy storage battery through the collection circuit of the present invention. Either of the first electronic switching device and the third electronic switching device, the second electronic switching device and the fourth electronic switching device, the fifth electronic switching device and the seventh electronic switching device, and the sixth electronic switching device and the eighth electronic switching device For example, when the first electronic switching device is turned on, the third electronic switching device is turned off, and when the second electronic switching device is turned off, the fourth electronic switching device is turned on.

Preferably, the monitoring and control circuit includes a connected single-chip microcomputer and an AD acquisition module, the AD acquisition module is responsible for collecting the voltage and current data of the electrical equipment, the AD acquisition module is sent back to the single-chip microcomputer in real time through SPI communication, and the single-chip microcomputer is finally processed and calculated through the data. The real-time power of the load is calculated, and the single-chip microcomputer controls each electronic switching device according to the real-time power output of the PWM pulse square wave of the electrical equipment. The single-chip microcomputer selects the STM32F103 minimum system single-chip microcomputer with extremely low power consumption, and the AD acquisition module in the monitoring and control circuit is combined with the single-chip microcomputer to perform preliminary acquisition and calculation of the real-time power of the load. When it is detected that the load power is small, the single-chip microcomputer controls the corresponding pins of the first electronic switching device, the third electronic switching device, the fifth electronic switching device and the seventh electronic switching device to output high and low levels through internal logic and algorithm judgment. . For example, the control realizes that the first electronic switching device is turned on, and the third electronic switching device is turned off; the fifth electronic switching device is turned on, and the seventh electronic switching device is turned off. Finally, the first energy capture unit continues to supply power to the electrical equipment, while the second energy capture unit disconnects the power supply path for the electrical equipment, while the branch for the energy storage battery is turned on to charge the energy storage battery.

Preferably, each electronic switching device has the same structure and includes an N-MOS field effect transistor. In the peripheral circuit of the N-MOS field effect transistor, the gate is connected to the positive electrode of the pulse control terminal for receiving the PWM pulse square wave. A pull-down resistor is also used to pull down, the source is connected to the rectified negative electrode, and the drain is used as the negative electrode of the final power output. The N-MOS field effect transistor with small on-resistance and easy to manufacture is used as the electronic switch, and the stability of the circuit is improved by the pull-down resistance. For example, when the pulse input is at a high level, the gate-source voltage VGS is greater than the turn-on voltage, and the source and drain of the N-MOS field effect transistor are turned on, which is equivalent to the switch being closed at this time, and the negative electrode of the output voltage is turned on, that is, the energy is at this time. The branch that flows to the electrical equipment or the branch that the electric energy flows to the energy storage battery is turned on. When the pulse input is low, the gate-source voltage VGS is less than the turn-on voltage, the source and drain of the N-MOS field effect transistor are disconnected, which is equivalent to the switch being disconnected at this time, and the negative electrode of the output voltage supplying power to the electrical equipment is disconnected. open or the negative branch that supplies power to the energy storage battery is disconnected.

The beneficial effects of the present invention are as follows: the present invention aims to improve the efficiency of the electric energy collection circuit and reduce the loss of the circuit, through the low power consumption main control system and the power real-time calculation algorithm, the electronic switching device is finally controlled for the communication between the load power supply and the battery charging. On the premise that the load is working normally, it provides the load with the least amount of power, that is, the monitoring and control circuit controls the electronic switching device to supply power to the load and the duty cycle is minimized, and the rest of the time is used to charge the battery; therefore, this The invention can effectively reduce the loss of the circuit, utilize the electric energy with high efficiency, not only ensure the normal operation of the load, but also charge and store the energy storage battery; the research and collection of efficient collection of micro-energy and renewable energy has important meaning.

Description of drawings

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of the connection and flow direction of electric energy and control signals in a low-power consumption energy collection circuit according to the present invention (the solid line represents the electric energy, and the dashed line represents the signal).

FIG. 2 is a circuit schematic diagram of each electronic switching device of the present invention.

Figure 3 is an overall schematic diagram of the combination of different electronic switching devices to supply power to the energy storage battery and the load.

In the figure: 1, the first energy capture unit; 2, the second energy capture unit; 3, the first full-bridge rectifier circuit; 4, the first electronic switching device; 5, the third electronic switching device; 6, the second electronic switch device; 7. Fourth electronic switching device; 8. First energy storage capacitor; 9. First voltage regulator circuit; 10. Electrical equipment; 11. Second full-bridge rectifier circuit; 12. Fifth electronic switching device; 13 , the seventh electronic switching device; 14, the sixth electronic switching device; 15, the eighth electronic switching device; 16, the second energy storage capacitor; 17, the second voltage regulator circuit; 18, the third voltage regulator circuit; 19, the storage Energy battery; 20. Monitoring and control circuit; 21. Pull-down resistor.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

A low power consumption energy collection circuit, comprising a first energy capture unit 1 and a second energy capture unit 2, an output end of the first energy capture unit 1 is connected with a first full-bridge rectifier circuit 3, and an output end of the full-bridge rectifier circuit is connected The first electronic switching device 4 and the third electronic switching device 5 are respectively connected in two ways, and the output end of the first electronic switching device 4 is connected with the second electronic switching device 6 and the fourth electronic switching device 7 in two ways. The output end of the electronic switching device 6 is connected to the electrode end of the electrical equipment 10 through the first energy storage capacitor 8 and the first voltage regulator circuit 9 in turn; the output end of the second energy capture unit 2 is connected to the second full bridge rectifier circuit 11 , the output end of the full-bridge rectifier circuit is respectively connected with the fifth electronic switching device 12 and the seventh electronic switching device 13 in two ways, and the output end of the seventh electronic switching device 13 is connected in two ways with the sixth electronic switching device 14 and the seventh electronic switching device 13 Eight electronic switching devices 15, the output end of the eighth electronic switching device 15 is sequentially connected to the other end of the electrode of the electrical equipment 10 through the second energy storage capacitor 16 and the second voltage regulator circuit 17; the third electronic switching device 5, the fifth The output ends of the electronic switching device 12 , the fourth electronic switching device 7 and the sixth electronic switching device 14 are connected in parallel with a third voltage stabilization circuit 18 , and the output end of the third voltage stabilization circuit 18 is connected with an energy storage battery 19 ; it also includes A monitoring and control circuit 20 for collecting the real-time power of the electrical equipment 10 and controlling the on-off time of each electronic switching device through the real-time power of the electrical equipment 10; the monitoring and control circuit 20 includes a connected single-chip microcomputer and an AD acquisition module. The module is responsible for collecting the voltage and current data of the electrical equipment 10. The AD acquisition module is sent back to the microcontroller in real time through SPI communication. The microcontroller finally calculates the real-time power of the load after data processing and calculation. The wave controls each electronic switching device; the structure of each electronic switching device is the same, including N-MOS field effect transistor. In the peripheral circuit of the N-MOS field effect transistor, the gate is connected to the positive electrode of the pulse control terminal for receiving PWM pulses At the same time, the gate is also pulled down by a pull-down resistor 21, the source is connected to the negative electrode after rectification, and the drain is used as the negative electrode of the final power output.

In the collection circuit of the present invention, the first energy capture unit 1 and the second energy capture unit 2 are responsible for converting mechanical energy such as vibration and noise in the environment into electrical energy, and floating energy from the environment to supply power for subsequent circuits. The energy harvesting unit 1 and the second energy harvesting unit 2 are structurally designed to combine the cyclic reciprocation of human motion, so the electrical energy collected by the energy harvesting unit is unidirectional pulsed power supply. The full-bridge rectifier circuit is responsible for converting the three-phase AC power output by the energy capture unit into DC power; each electronic switching device is responsible for controlling the on-off of the power supply circuit of the load or the energy storage battery 19; each voltage regulator circuit is responsible for converting the rectifier circuit into The direct current is converted to the appropriate voltage required by the load. The monitoring and control circuit 20 controls each electronic switching device to perform control to ensure that the load works normally under the state of the lowest current. When the human body moves, the mechanical energy generated by each body part can be converted into electric energy, and the generated electric energy can finally realize the function of supplying power to the smart wearable or charging the energy storage battery through the collection circuit of the present invention. The first electronic switching device 4 and the third electronic switching device 5, the second electronic switching device 6 and the fourth electronic switching device 7, the fifth electronic switching device 12 and the seventh electronic switching device 13, and the sixth electronic switching device 14 and the third electronic switching device The disconnection and conduction between the eight electronic switching devices 15 are in opposite states. For example, when the first electronic switching device 4 is turned on, the third electronic switching device 5 is turned off, and when the second electronic switching device 6 is turned off , the fourth electronic switching device 7 is turned on and so on. The single-chip microcomputer selects the STM32F103 minimum system single-chip microcomputer with extremely low power consumption, and the AD acquisition module in the monitoring and control circuit 20 is combined with the single-chip microcomputer to perform preliminary acquisition and calculation of the real-time power of the load. The N-MOS field effect transistor with small on-resistance and easy to manufacture is used as the electronic switch, and the stability of the circuit is improved through the pull-down resistor 21 . For example, when the pulse input is at a high level, the gate-source voltage VGS is greater than the turn-on voltage, and the source and drain of the N-MOS field effect transistor are turned on, which is equivalent to the switch being closed at this time, and the negative electrode of the output voltage is turned on, that is, the energy is at this time. The branch that flows to the electrical equipment 10 or the branch that the electrical energy flows to the energy storage battery 19 is turned on. When the pulse input is low level, the gate-source voltage VGS is less than the turn-on voltage, the source and drain of the N-MOS field effect transistor are disconnected, which is equivalent to the switch being disconnected at this time, and the output voltage of the power supply device 10 is negative. Disconnected or the negative branch supplying power to the energy storage battery 19 is disconnected.

When it is detected that the load power is small, the single-chip microcomputer controls the corresponding pins of the first electronic switching device 4 and the third electronic switching device 5, the fifth electronic switching device 12 and the seventh electronic switching device 13 through internal logic and algorithm judgment. Output high and low level. For example, the control realizes that the first electronic switching device 4 is turned on, the third electronic switching device 5 is turned off; the fifth electronic switching device 12 is turned on, and the seventh electronic switching device 13 is turned off. Finally, the first energy capture unit 1 continues to supply power to the electrical equipment 10, while the second energy capture unit 2 disconnects the power supply path to the electrical equipment 10, and the branch that supplies power to the energy storage battery 19 is turned on. The battery 19 can be charged. The electric energy collected by the second energy harvesting unit 2 charges the energy storage battery 19 , while the electric energy of the first energy harvesting unit 1 passes through the second electronic switching device 6 and the fourth electronic switching device 7 after passing through the first electronic switching device 4 . . At this time, the AD acquisition circuit and the low-power STM32F103 microcontroller in the monitoring and control circuit 20 collect and calculate the real-time power of the electrical equipment 10 again. If the load power is still small at this time, the microcontroller can combine the load power and the discharge time of the energy storage capacitor to control the pins of the second electronic switching device 6 and the fourth electronic switching device 7 to output a specific matching two-way pulse level through an intelligent algorithm Complementary level square wave. That is, when the square wave signal controlling the second electronic switching device 6 is at a high level, the square wave signal controlling the fourth electronic switching device 6 is at a low level. The two signal states are always opposite. At this time, the second electronic switching device 6 is turned on, and the fourth electronic switching device 7 is turned off.

In the square wave duty cycle output control calculation algorithm, the following parameters will be involved:

(1) The real-time power of the electrical equipment 10;

(2) The discharge time of the energy storage capacitor of the current electrical equipment 10;

(3) For the duty cycle pulse control at the previous moment, the charging voltage of the charging capacitor at this time, so that the charging time of the capacitor at this time can be calculated;

The monitoring and control circuit 20 finally combines the charging and discharging time of the capacitor and the real-time power of the electrical equipment 10, and finally outputs a specific pulse square wave whose duty cycle can be changed in real time with the electrical equipment 10 through comprehensive calculation, ensuring the electrical equipment 10. While it can work normally, it can also charge the energy storage battery 19 .

The electrical energy passes through the first energy storage capacitor 8 after passing through the second electronic switching device 6 . The pulsed square wave control is used for the control of the second electronic switching device 6 and the fourth electronic switching device 7, so the electric energy at this time is intermittent electric energy. Therefore, the function of the first energy storage capacitor 8 here is to charge the energy storage capacitor and supply power to the subsequent electrical equipment 10 when the square wave is at a high level; when the pulsed square wave is at a low level, the energy storage capacitor Discharge to supply power to subsequent loads to ensure that subsequent loads can continue to work.

In the above scheme, the first, third, fifth, and seventh electronic switching devices are used to preliminarily select the power flow to the branch, and then the second, fourth, sixth, and eighth electronic switching devices are used to differentiate the power for the second time. Stream selection. Through the pulsed square wave control, the electric energy is effectively shunted, which greatly reduces the unnecessary loss of high voltage on the voltage regulator circuit, reduces the loss of the circuit, and improves the collection efficiency of the energy collection circuit.

Figure 3 depicts the design schematic diagram of the electronic switching device part in the circuit as a whole. After passing through the rectifier circuit, the energy harvesting unit outputs a high-voltage direct current, and the first electric energy shunting is performed on the negative electrode of the direct current. In the first step, a branch after the electric energy shunting branch directly charges the energy storage battery 19 The power supply is supplied, and a second power diversion is carried out on the other branch. The second power split is for more accurate and efficient use of power. It is ensured that the load is powered by the minimum electric energy under the premise of normal operation. After the second shunt, one branch supplies power to the energy storage battery 19, and the other branch flows through the energy storage capacitor and then passes through the voltage stabilizing circuit, and supplies power to the load after being stabilized to a suitable voltage. The function of the energy storage capacitor is to ensure that the intermittent power provided to the load after the second power shunt can still make the load continue to work through the continuous charging and discharging of the capacitor. The shunting of electric energy reduces the average voltage reaching the voltage stabilizing circuit, avoids the loss of a large amount of electric energy in the voltage stabilizing circuit, reduces the power consumption of the circuit, and improves the efficiency of energy collection at the same time.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (3)

1. The low-power-consumption energy collection circuit is characterized by comprising a first energy harvesting unit (1) and a second energy harvesting unit (2), wherein the output end of the first energy harvesting unit (1) is connected with a first full-bridge rectification circuit (3), the output end of the first full-bridge rectification circuit (3) is divided into two paths and is respectively connected with a first electronic switch device (4) and a third electronic switch device (5), the output end of the first electronic switch device (4) is divided into two paths and is connected with a second electronic switch device (6) and a fourth electronic switch device (7), and the output end of the second electronic switch device (6) is connected to one end of an electrode of electric equipment (10) through a first energy storage capacitor (8) and a first voltage stabilizing circuit (9) in sequence; the output end of the second energy harvesting unit (2) is connected with a second full-bridge rectification circuit (11), the output end of the second full-bridge rectification circuit (11) is divided into two paths and is respectively connected with a fifth electronic switch device (12) and a seventh electronic switch device (13), the output end of the seventh electronic switch device (13) is divided into two paths and is connected with a sixth electronic switch device (14) and an eighth electronic switch device (15), and the output end of the eighth electronic switch device (15) is connected to the other end of the electrode of the electric equipment (10) through a second energy storage capacitor (16) and a second voltage stabilizing circuit (17) in sequence; the output ends of the third electronic switch device (5), the fifth electronic switch device (12), the fourth electronic switch device (7) and the sixth electronic switch device (14) are connected in parallel and then connected with a third voltage stabilizing circuit (18), and the output end of the third voltage stabilizing circuit (18) is connected with an energy storage battery (19); the power consumption monitoring and controlling system further comprises a monitoring and controlling circuit (20) which is used for collecting the real-time power of the electric equipment (10) and controlling the on-off time of each electronic switch device through the real-time power of the electric equipment (10).

2. The low-power-consumption energy collection circuit according to claim 1, wherein the monitoring and control circuit (20) comprises a single chip microcomputer and an AD collection module which are connected, the AD collection module is responsible for collecting voltage and current data of the electric equipment (10), the AD collection module is transmitted back to the single chip microcomputer in real time through SPI communication, the single chip microcomputer finally calculates real-time power of a load through data processing and calculation, and the single chip microcomputer outputs PWM pulse square waves to control each electronic switching device according to the real-time power of the electric equipment (10).

3. The low-power consumption energy acquisition circuit according to claim 1 or 2, wherein each electronic switching device has the same structure and comprises an N-MOS field effect transistor, and in a peripheral circuit of the N-MOS field effect transistor, a gate is connected with a positive electrode of a pulse control terminal for receiving a PWM pulse square wave, and is pulled down by a pull-down resistor (21), a source is connected with a rectified negative electrode, and a drain is used as a negative electrode of a final electric energy output.

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