CN115664045A - Non-contact electric field optimization energy taking method suitable for self energy taking of micro sensor - Google Patents
Non-contact electric field optimization energy taking method suitable for self energy taking of micro sensor Download PDFInfo
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Abstract
The invention discloses a non-contact electric field optimization energy taking method suitable for self energy taking of a miniature sensor, which comprises the following steps: 1) Placing a non-contact electric field energy taking device in an alternating electric field; 2) Alternating current formed by the metal upper polar plate and the metal lower polar plate under the action of an electric field is transmitted to a full-wave rectification bridge circuit; 3) The full-wave rectification bridge circuit rectifies the alternating current into direct current for output and supplies the direct current to the energy storage capacitor C g Charging; the detection and control module controls the high-frequency switch to be conducted so as to enable the energy storage capacitor C to be connected g The load Z is controlled by a flyback transformer and an uncontrollable full-wave rectifier bridge L Discharging; the invention provides a non-contact electric field coupling energy-taking method suitable for self energy-taking of a micro sensor, provides an approximate energy-taking estimation method suitable for energy-taking by combining energy-taking calculation, and provides energy and electricity in the energy-taking processThe voltage optimization scheme does not need an external power supply, so that stable voltage and power are provided for the sensor, and the normal work and running measurement of the electric field sensor are ensured.
Description
Technical Field
The invention relates to the field of online detection of power systems, in particular to a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor.
Background
Along with the construction of a smart power grid, a large number of electric field sensors and online monitoring devices with low power consumption are applied to the power grid to acquire key data information of the operation of the power grid. When measuring the electric field intensity, the sensor is often required to be in a high-energy electromagnetic environment, so how to supply energy to the electric field sensor becomes a new technical difficulty. There are two main energy taking modes at present: transmitting power supply and automatically acquiring energy. The transmission power supply mode is mainly to transmit energy from the ground to an online measuring device through optical fibers or microwaves, and the energy supply mode has the main defects of high manufacturing cost and unsuitability for mass popularization. Self-energy extraction is therefore the main development of electric field sensors.
Meanwhile, the electric field sensor gradually tends to be miniaturized and self-powered in recent years, and the related theoretical research still cannot meet the requirements of practical application. Common self-energy-taking modes include a battery mode, solar energy taking, energy taking by vibration of piezoelectric materials, wind energy taking, magnetic induction energy taking, temperature difference energy taking and the like. The battery mode needs to be replaced by regularly powering off; the solar energy or wind energy has strong randomness and is easily influenced by environmental factors; magnetic induction energy taking is influenced by unstable load current, and the line cannot normally work when power is cut off, so that a large power supply blind area exists, and the stability of power supply is difficult to ensure; other ways are limited by natural conditions and also affect the stability of the power supply. Compared with other self-energy-taking modes, the electric field coupling energy-taking power supply mode is easy to realize based on an electric field environment. The research of voltage self-energy taking supplies power to the electric field sensor, and achieves balance of supply and demand, energy consumption and self-energy taking at the same time, thereby achieving the purpose of self-sufficiency of a closed system.
Compared with the conventional electric field energy taking method, the electric field energy taking method applicable to the micro sensor provides more strict requirements: 1. the miniaturization of the sensor requires that the volume of a metal polar plate induced by an electric field is smaller and the distance is closer; 2. the provided power and voltage are lower, compared with the common power requirement of a load, the power requirement is mW, and the voltage requirement is about 3-15V; 3. the energy taking efficiency requirement is higher, the loss requirement is lower, and the circuit is simplified as much as possible to reduce the volume of the energy taking circuit.
In order to meet the above requirements, some researchers have proposed an alternating electric field energy-taking circuit, which includes a high-potential conductor, an induction electrode ground capacitor and an energy-taking capacitor, wherein one end of the energy-taking capacitor is connected to the high-potential conductor, and the other end of the energy-taking capacitor is grounded via the induction electrode ground capacitor. However, the potential electric energy loss is not considered in the circuit, a large number of MOS (metal oxide semiconductor) tubes are needed, energy release at the energy storage peak value each time cannot be guaranteed, the efficiency of practical application is reduced, the voltage and the power which can be provided for the sensor are small, and meanwhile, the metal electrode is large in size and cannot meet the energy taking requirement of the micro electric field sensor. The students also put forward a space electric field energy taking device which can directly supply power for small-power automatic monitoring or communication equipment at a low potential of the space electric field and can also supply power for high-power intermittently working equipment by means of an energy storage device. However, the applicable voltage level is limited, so that a large number of capacitor banks are required, and the cost is increased; the self-energy-taking magnitude is far inferior to that of a high-voltage strong electric field due to weak electric field intensity, and therefore, the micro-sensor can only be used for a micro-sensor with low energy consumption and low voltage level; in the working process of the device, as a certain resistance possibly exists, the resonance energy consumption can further reduce the obtained energy, and the application condition is severer.
Disclosure of Invention
The invention aims to provide a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor, which comprises the following steps:
1) Placing a non-contact electric field energy taking device in an alternating electric field; the non-contact electric field energy taking device comprises a metal upper polar plate, a metal lower polar plate, a full-wave rectification bridge circuit and an energy storage capacitor C which are mutually parallel g The system comprises a high-frequency switch, a flyback transformer, an uncontrollable full-wave rectifier bridge, a micro-sensor module and a detection and control module; the micro-meterThe type sensor module is equivalent to a load Z L The device comprises a signal acquisition circuit, a data processing circuit and a wireless communication circuit, wherein the signal acquisition circuit, the data processing circuit and the wireless communication circuit are electrically connected with a metal upper polar plate and a metal lower polar plate;
the detection and control module stores upper limit voltage V of a capacitor + Lower limit voltage V of capacitor - ；
2) The alternating current formed by the metal upper polar plate and the metal lower polar plate under the action of the electric field is transmitted to a full-wave rectification bridge circuit;
3) The full-wave rectification bridge circuit rectifies the alternating current into direct current for output and supplies the direct current to the energy storage capacitor C g Charging;
in the capacitor charging process, the detection and control module detects the energy storage capacitor C in real time g Voltage across, as energy storage capacitor C g The voltage at both ends is greater than or equal to the upper limit voltage V + The detection and control module controls the high-frequency switch to be conducted to enable the energy storage capacitor C to be conducted g The load Z is controlled by a flyback transformer and an uncontrollable full-wave rectifier bridge L Discharging;
in the capacitor discharging process, the detection and control module detects the energy storage capacitor C in real time g Voltage across, as energy storage capacitor C g The voltage at two ends is less than or equal to the lower limit voltage V of the capacitor - When the high-frequency switch is turned off, the detection and control module controls the high-frequency switch to be turned off, so that the metal upper polar plate and the metal lower polar plate are opposite to the energy storage capacitor C g Charging;
further, the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - Is in a preset range of [0.3V ] cc ，0.7V cc ](ii) a Vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation;
and the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - Simultaneously, the following requirements are met: 1) V + >V - ；2)V + -V - ≤0.5V cc 。
Further, an energy storage capacitor C g The maximum value Vcc of the direct current voltage at two ends meets the following formula when the direct current voltage is saturated:
in the formula of U c For an energy-storage capacitor C g Monitoring the voltage at two ends; t is time; τ is a time constant.
Further, updating the upper limit voltage V of the capacitor according to the discharge curve and the charge curve of the energy storage capacitor + Lower limit voltage V of capacitor - Comprises the following steps:
a) Determining the intersection point S after the translation of the discharge curve and the charge curve of the energy storage capacitor 1 ；
b) Determining the intersection point S 1 Corresponding voltage, denoted as V S ；
c) Determining the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - The constraint of (2): 1) V + ，V - ∈[-20％V S ，+20％V S ]；2)V + >V - ；3)V + -V - ≤V S ；
d) Determining the upper limit voltage V of the capacitor according to the constraint condition + Lower limit voltage V of capacitor - The value of (c).
Further, the on-off frequency of the high-frequency switch is f, namely:
further, in unit time, the energy storage capacitor C g Discharge energy
As follows:
further, the energy Σ W obtained by the load per unit time 2 As follows:
in the formula, η is the discharge efficiency.
Furthermore, in unit time, a secondary side capacitor C of the flyback transformer s Stabilized voltage sigma U on out As follows:
in the formula, sigma W 2 Is the energy obtained by the load in unit time; u shape omax And storing energy for the upper limit value of the load end.
Further, the metal upper polar plate is connected with the high-voltage charged body.
The technical effects of the invention are undoubted, the invention provides a non-contact electric field coupling energy taking method suitable for self energy taking of a micro sensor, provides an energy taking approximate estimation method suitable for energy taking and provides an energy and voltage optimization scheme in an energy taking process by combining energy taking calculation, and does not need an external power supply, so that stable voltage and power are provided for the sensor, and normal work and operation measurement of the electric field sensor are ensured.
The invention can meet the special requirements of small volume, low power, low voltage and low loss of the miniature electric field sensor, provides the energy acquisition process and the theoretical calculation of the energy and voltage obtained by the method, can meet the energy consumption requirement of the miniature sensor in a high-voltage environment, and can contribute to realizing the power consumption balance of the electric field sensor.
The invention provides an energy and voltage optimization scheme and a practical approximate estimation method in the energy taking process, which greatly improve the self-energy supply efficiency of the sensor, can quickly calculate and analyze on engineering, summarizes key factors influencing the energy taking efficiency, and defines the direction of main contents of practical application, optimization adjustment and test on the subsequent miniature electric field sensor engineering.
The invention is suitable for self energy taking of the micro electric field sensor, the related elements are simple, easy to obtain and low in cost, and compared with the traditional electric field energy taking mode, the space and materials are greatly saved. The method has less external limitation, can work only under the condition of a high-voltage alternating electric field, has short time from the first capacitor energy storage to the last voltage stabilization, and can work quickly and stably, thereby having higher reliability.
Drawings
FIG. 1 is a schematic diagram of a self-energy-taking method of a micro electric field sensor;
FIG. 2 shows an energy storage capacitor C g Energy-taking optimization and approximate estimation.
Detailed Description
The present invention is further illustrated by the following examples, but it should not be construed that the scope of the above-described subject matter is limited to the following examples. Various substitutions and alterations can be made without departing from the technical idea of the invention and the scope of the invention is covered by the present invention according to the common technical knowledge and the conventional means in the field.
Example 1:
referring to fig. 1 to 2, a non-contact electric field optimized energy extraction method suitable for self-energy extraction of a micro sensor comprises the following steps:
1) Placing a non-contact electric field energy taking device in an alternating electric field; the non-contact electric field energy taking device comprises a metal upper polar plate, a metal lower polar plate, a full-wave rectification bridge circuit and an energy storage capacitor C which are mutually parallel g High-frequency switch, flyback transformer, uncontrollable full-wave rectifier bridge, and micro-sensor module (equivalent to load Z) L ) The detection and control module;
the miniature sensor module comprises a signal acquisition circuit, a data processing circuit, a wireless communication circuit and the like which are connected with the metal polar plate;
the detection and control module stores upper limit voltage V of capacitor + Lower limit voltage V of capacitor - ；
2) Alternating current formed by the metal upper polar plate and the metal lower polar plate under the action of an electric field is transmitted to a full-wave rectification bridge circuit;
3) Full-wave rectifier bridgeThe type circuit rectifies the alternating current into direct current for output and charges the energy storage capacitor C g Charging;
in the capacitor charging process, the detection and control module detects the energy storage capacitor C in real time g Voltage across, as energy storage capacitor C g The voltage at both ends is greater than or equal to the upper limit voltage V + The detection and control module controls the high-frequency switch to be conducted to enable the energy storage capacitor C to be conducted g The load Z is controlled by a flyback transformer and an uncontrollable full-wave rectifier bridge L Discharging;
in the capacitor discharging process, the detection and control module detects the energy storage capacitor C in real time g Voltage across, as energy storage capacitor C g The voltage at two ends is less than or equal to the lower limit voltage V of the capacitor - When the high-frequency switch is turned off, the detection and control module controls the high-frequency switch to be turned off, so that the metal upper polar plate and the metal lower polar plate are opposite to the energy storage capacitor C g Charging;
upper limit voltage V of capacitor + Lower limit voltage V of capacitor - Is in a preset range of [0.3V ] cc ，0.7V cc ](ii) a Vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation;
and the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - Simultaneously, the following requirements are met: 1) V + >V - ；2)V + -V - ≤0.5V cc 。
Energy storage capacitor C g The maximum value Vcc of the direct current voltage at two ends meets the following formula when the direct current voltage is saturated:
in the formula of U c For an energy-storage capacitor C g Monitoring the voltage at two ends; t is time; τ is the time constant.
Updating the upper limit voltage V of the capacitor according to the discharge curve and the charge curve of the energy storage capacitor + Lower limit voltage V of capacitor - Step bag (2)Comprises the following steps:
a) Determining the intersection point S after the translation of the discharge curve and the charge curve of the energy storage capacitor 1 ；
b) Determining the intersection point S 1 Corresponding voltage, denoted as V S ；
c) Determining the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - The constraint of (2): 1) V + ，V - ∈[-20％V S ，+20％V S ]；2)V + >V - ；3)V + -V - ≤V S ；
d) Determining the upper limit voltage V of the capacitor according to the constraint condition + Lower limit voltage V of capacitor - The value of (c).
The on-off frequency of the high-frequency switch is f, namely:
in unit time, the energy storage capacitor C g Discharge energy
As follows:
energy sigma W obtained by load in unit time 2 As follows:
where η is the discharge efficiency.
Secondary side capacitor C of flyback transformer in unit time s Stabilized voltage sigma U on out As follows:
in the formula, sigma W 2 Is the energy obtained by the load in unit time; u shape omax And storing the energy of the load end.
The metal upper polar plate is connected with the high-voltage charged body.
Compared with a common electric field coupling energy taking mode, the micro electric field sensor has the advantages of small volume, low power, low voltage and low loss required by self energy taking, so that the traditional metal electrode electric field induction-rectification filtering-energy storage and energy release mode cannot be directly adopted. The size of the metal polar plate must be limited within 0.1m x 0.1m, the induction polar plate is externally connected with a full-wave rectification bridge circuit, the power consumption of the diode is minimum, and alternating voltage is converted into direct voltage V cc Then passes through an energy storage capacitor C g Energy is stored. Because the metal polar plate of the miniature electric field sensor is small, the obtained voltage is in direct proportion to the area of the polar plate, and the miniature electric field sensor can directly pass through C even under a higher voltage level g The acquired energy is also at the level of microwatts and cannot reach the energy consumption of the sensor at the level of milliwatts, so that the high-frequency switch and the voltage monitoring circuit can be utilized to monitor and conduct the circuit to enable the energy storage capacitor C to be driven when the capacitor voltage reaches a set threshold value g Releasing energy; when the capacitor voltage drops to a set threshold, the monitoring and shutdown circuit prompts the energy storage capacitor C g Energy is stored, and not only can the secondary side energy storage capacitor C of the flyback transformer be utilized s The pumping effect obtains larger energy, and simultaneously promotes the flow of the inductive charges of the metal polar plate, thereby improving the efficiency of energy collection and solving the problem of insufficient energy taking power of the traditional direct electric field. The threshold value extraction method greatly influences the final energy extraction efficiency, so deduction must be carried out. The flyback transformer has few turns and low loss, can effectively lift the primary voltage, can provide stable power supply voltage for a load through full-wave rectification, and solves the problem of pain caused by low voltage of the miniature electric field sensor.
Example 2:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor comprises the following steps:
effective value U of alternating voltage of metal polar plate 1 Through the whole processWave rectification bridge circuit rear energy storage capacitor C g Maximum value Vcc of DC voltage at two ends in saturation and time-varying monitoring value U c Secondary side energy storage capacitor C s The electric field sensor load is equivalent to Z L . Because the power supply voltage of the on-line monitoring equipment such as the miniature electric field sensor is not high (generally 3V-15V) and the working energy consumption is in the milliwatt level, C is g The size of the energy storage and release device is very critical, and not only the size of energy consumption and the required voltage need to be considered, but also the time problem of energy storage and release needs to be considered. Is composed of
The charging (discharging) process of the capacitor is non-linear. When the capacitor voltage reaches a set threshold, i.e. the upper limit voltage V + Transmitting a signal to the detection circuit when it is detected that the upper limit voltage V is exceeded + Controlling the switch to be turned on to discharge the capacitor until the voltage across the capacitor is reduced to a lower limit voltage V - At the moment, the switch is disconnected, and the capacitor stores energy again.
U c ≥V + Switch on
U c ≤V - Switch cut-off
Let t 1 、t 2 The charging and discharging time in one period T is respectively, and the voltage on two sides of the energy-taking capacitor is always at V + And V - The interval oscillates. The energy transferred to the discharge circuit per cycle is
If the on-off of the switch is set to f times in 1s, i.e. the switching frequency is f, the accumulated transmission energy in 1s is
Due to C g Being constant, we found that f exists with V + And V - Relationship of negative correlation, in particular when Δ U = V + -V - When the capacitance is reduced, the time for charging and discharging the capacitance in the process is reduced, and the frequency f is increased accordingly, so that the functional relationship between the two is very important and influences the effect of optimizing energy extraction. Since the charging voltage range of the capacitor is [0,Vcc']The charging time of the capacitor is t 1 Discharge time of t 2 And the on-off frequency of the switch is f:
the capacitor has a charge-discharge period of T, with (7)
The frequency f of the on-off of the switch can be obtained
As can be seen from equation (8), the maximum charging voltage V of the capacitor is obtained at a time constant tau cc Under certain conditions, the magnitude of f is determined by the threshold voltage. The energy obtained in unit time by bringing the formula (4) into effect is (9)
When energy passes through the flyback transformer to the load end, the equivalent load of the secondary side of the transformer is Z L And the discharge circuit efficiency is eta, the energy obtained by the load in unit time (1 s) is (10):
if the working time of the energy-taking circuit is t s, the total power obtained in the period of time is
Converted into secondary side capacitor C s Stabilized voltage U on out
In the following simulations it can be seen that if the load side is always storing energy, U out And the energy storage device continuously rises in a step waveform in the period t until reaching the upper limit value of the energy storage of the load end.
It follows that by appropriate design of the switching frequency of the switch and the relevant parameters of the transformer, in particular C g 、V + And V - The aim of continuously delivering energy to the load end can be achieved, and the energy W delivered in each unit time is theoretically 2 And an output voltage U out The micro electric field sensor is basically constant, and can meet the requirements of small self-energy-taking volume, low power, low voltage and small loss of the micro electric field sensor.
From the analysis of the above method, it can be seen that V + And V - The determination of (d) is particularly important for the energy extraction process and is an important parameter affecting the extracted energy (equation 11) and voltage (equation 13). Thus, V can be determined based on the cut-and-complement method and the median-of-integral theorem + And V - Approximately value of (a) and approximately estimate energy and voltage are largeIs small. FIG. 1 demonstrates an energy storage capacitor C g Energy-taking approximate estimation method:
first, V is clarified + And V - Selective concealment condition of (2): first, if V + And V - If the difference is too large, the energy charging and releasing time in one period is too long, and the efficiency is greatly reduced; second, if V + And V - If the difference is too small, although the energy charging time and the energy releasing time in one period are reduced, the energy obtained in the period is also greatly reduced, and the efficiency is also reduced; thirdly, the slope of the charging and discharging curve is decreased from infinity to 0 if V + And V - At the same time, smaller or larger, will result in a charging time t 1 And energy release time t 2 One shorter and one longer. Therefore, the following two conclusions can be drawn: 1) V + And V - The difference is moderate, at least less than 0.5V cc 。2)V + And V - Neither too large nor too small to ensure that the slopes of the energy-taking and energy-releasing process function curves reach the maximum as simultaneously as possible.
Based on the two conclusions, the intersection point of the translated charge-discharge curve is selected as the reference point S 1 Reference point S 1 The corresponding voltage is just 0.5V cc The charge-discharge curve after translation is about 0.5V cc And (4) axial symmetry. At selection V + And V - Not only about 0.5V cc Axial symmetry while satisfying as much as possible at S 1 Corresponding to a voltage in the range of + -20%, i.e. 0.3V cc -0.7V cc 。
To select
For example, further analysis applied approximate estimation methods. Let V + Respectively intersecting with the charge-discharge curves A and B; v - Respectively intersecting with the charging and discharging curves at C and D; arc AB to arc CD in S 1 (ii) a AB crossing CD with S 2 . For simple estimation of power, by S 2 Two triangles delta BCD and delta ACD in a rectangle ABCD with a centroid approximately replace the charge and discharge process of a capacitor, and the actual error is only the area of a graph formed by two times of arcs AB and AB. The reason why this can be simplified is that: first, a micro electric fieldThe power obtained by the sensor self-energy taking is small, so that the estimation error can be ignored; second, selected V + And V - It is very reasonable that the curve slopes of the arc AB and the arc CD are large, and the change rate of the slope is small, so that the curve can be changed into straight, and the curve can be ignored and ignored in power estimation. Therefore, when approximately obtaining energy power estimation, the capacitor C can be replaced by an isosceles triangle sawtooth wave g The charging and discharging process of (2) is substituted into the formula (9) to obtain energy within the time t:
according to the cut-and-fill method, the graph area formed by the arcs AB and AB is equal to the graph area of the arcs CD and CD, and the voltage can be directly estimated through the integral median theorem:
due to t 1 And t 2 The average voltage is 0.5V because of the equal size cc . Setting the transformation ratio of the flyback transformer to k, the voltage U at two ends of the load is finally obtained after full-wave rectification of the secondary side L ：
U L ＝0.45kV CC (17)
Therefore, based on the approximate calculation method, only the effective value U of the alternating voltage of the metal plate is obtained 1 The self-energized energy and the average voltage of the micro electric field sensor can be quickly estimated according to the formulas (14) and (17) by using parameters such as the working time t, the transformation ratio k and the like. At the same time V + And V - The problems of small self-energy-taking metal polar plate and low energy-taking efficiency of the miniature electric field sensor are solved, and three requirements of the self-energy-taking metal polar plate are met.
Analyzing main influence factors influencing the self-energy taking efficiency and the voltage taking of the miniature electric field sensor:
1)U 1 (V cc ) The influence of (c): as can be seen from equations (14) and (17), the voltage U in the environment of the alternating electric field 1 (V cc ) The higher the rating, the greater the corresponding self-energizing energy magnitude and voltage. It can therefore be concluded that an environment with a higher voltage level is more favorable for the micro electric field sensor to self-extract energy.
2)C g The influence of (a): as can be seen from the formula, C is selected g In time, a method of connecting capacitors in parallel can be adopted to obtain a larger capacitance value. The essence of the discharge circuit is a second-order oscillation circuit, and energy is transmitted back and forth in the transformer inductor and the energy-taking capacitor, so that the switch is controlled to be at V - And the current is turned off to prevent the current from flowing back to the capacitor, so that the energy is transmitted to the secondary side. Due to C g Smaller, and C s Greater, resulting in an oscillating angular frequency ω r Very small, omega s Is relatively large. Therefore, the capacitance C at the primary side needs to be ensured g The time required to transfer energy into the flyback transformer is much less than C g Charging time, secondary side capacitance C s The charging time is less than C g Charging time, is relatively difficult. But C is g The use of an excessively large capacitor has a low withstand voltage and an upper limit, and it is difficult to further increase the voltage.
3)Z L The influence of (a): z is a linear or branched member L The self-powered sensor is connected with a load, namely the impedance in circuits such as a micro electric field sensor acquisition module, a data processing module, a wireless module and the like. From the formula, it can be seen that the load Z L Is favorable for stabilizing the voltage U s . But Z L After increasing to a certain extent, U s The rate of change is much less than the rate of change of the load, resulting in a potential failure to provide a voltage sufficient for load operation. Therefore, when the load is actually adjusted, the supply voltage is satisfied as much as possible, and then the load is increased appropriately.
4)V + And V - The influence of (c): whether V or not + Too large or V - Too small may result in a decrease in energy extraction efficiency. V + And V - The difference is moderate, at least less than 0.5V cc 。V + And V - Neither too large nor too small is necessary to ensure that the slopes of the energy-taking and energy-releasing process function curves are maximized as simultaneously as possible. It is therefore recommended that V be selected + And V - Not only about 0.5V cc Axial symmetry while satisfying as much as possible at S 1 Corresponding to a voltage in the range of + -20%, i.e. 0.3V cc -0.7V cc 。
5) Influence of η: the self-energy-taking loss of the miniature electric field sensor mainly comes from two aspects of element loss and switching loss. The existing high-frequency switching technology is mature, so that the main task is to control the relation between the power-on frequency of the switch and the charge and discharge power of the capacitor. Since the current flowing through each element is small in a high-voltage environment, the element loss mainly depends on the voltage of the use environment. Therefore, in order to reduce the element loss, the method is more suitable for self-energy extraction at high voltage.
Example 3:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor comprises the following steps:
1) Placing a non-contact electric field energy taking device in an alternating electric field; the non-contact electric field energy taking device comprises a metal upper polar plate, a metal lower polar plate, a full-wave rectification bridge circuit and an energy storage capacitor C which are mutually parallel g The system comprises a high-frequency switch, a flyback transformer, an uncontrollable full-wave rectifier bridge, a micro-sensor module and a detection and control module; the miniature sensor module is equivalent to a load ZL and comprises a signal acquisition circuit, a data processing circuit and a wireless communication circuit, wherein the signal acquisition circuit is electrically connected with the metal upper polar plate and the metal lower polar plate;
the detection and control module stores upper limit voltage V of capacitor + Lower limit voltage V of capacitor - ；
2) The alternating current formed by the metal upper polar plate and the metal lower polar plate under the action of the electric field is transmitted to a full-wave rectification bridge circuit;
3) The full-wave rectification bridge circuit rectifies the alternating current into direct current for output and supplies the direct current to the energy storage capacitor C g Charging;
during the capacitor charging process, the detection and control module detects the capacitor in real timeEnergy capacitor C g Voltage across, as energy storage capacitor C g The voltage at both ends is greater than or equal to the upper limit voltage V + When the high-frequency switch is switched on, the detection and control module controls the high-frequency switch to be switched on, so that the energy storage capacitor C is enabled to be connected g By flyback transformer, uncontrollable full-wave rectifier bridge, to load Z L Discharging;
in the capacitor discharging process, the detection and control module detects the energy storage capacitor C in real time g Voltage across, as energy storage capacitor C g The voltage at two ends is less than or equal to the lower limit voltage V of the capacitor - When the high-frequency switch is turned off, the detection and control module controls the high-frequency switch to be turned off, so that the metal upper polar plate and the metal lower polar plate are enabled to be opposite to the energy storage capacitor C g And (6) charging.
Example 4:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor is mainly disclosed in embodiment 3, wherein the upper limit voltage V of a capacitor + Lower limit voltage V of capacitor - Is in a preset range of [0.3V ] cc ，0.7V cc ](ii) a Vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation;
and the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - Simultaneously, the following requirements are met: 1) V + >V - ；2)V + -V - ≤0.5V cc 。
Example 4:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor is mainly disclosed in embodiment 3, wherein an energy storage capacitor C g The maximum value Vcc of the direct current voltage at two ends meets the following formula when the direct current voltage is saturated:
in the formula of U c For an energy-storage capacitor C g Monitoring values of voltages at two ends; t is time; τ is a time constant; vcc is energy storageContainer C g The maximum value of the direct current voltage at two ends when the voltage is saturated.
Example 5:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor is mainly disclosed in embodiment 3, wherein the upper limit voltage V of a capacitor is updated according to a discharge curve and a charging curve of an energy storage capacitor + Lower limit voltage V of capacitor - Comprises the following steps:
1) Determining the intersection point S of the discharge curve and the charge curve of the energy storage capacitor after translation 1 ；
2) Determining the intersection point S 1 Corresponding voltage, denoted as V S ；
3) Determining the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - The constraint of (2): 1) V + ，V - ∈[-20％V S ，+20％V S ]；2)V + >V - ；3)V + -V - ≤V S ；
4) Determining the upper limit voltage V of the capacitor according to the constraint condition + Lower limit voltage V of capacitor - The value of (c).
Example 6:
a non-contact electric field optimized energy extraction method suitable for self energy extraction of a micro sensor, the main contents of which are shown in embodiment 3, wherein the on-off frequency of a high-frequency switch is f, that is:
in the formula, vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is a time constant.
Example 7:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor is mainly disclosed in embodiment 3, wherein in unit time, an energy storage capacitor C g Discharge energy
As follows:
in the formula, vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is a time constant.
Example 8:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor is mainly disclosed in embodiment 3, wherein within unit time, energy sigma W obtained by a load 2 As follows:
in the formula, eta is the discharge efficiency; vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is a time constant.
Example 9:
a non-contact electric field optimization energy obtaining method suitable for self energy obtaining of a micro sensor is mainly disclosed in embodiment 3, wherein in unit time, a secondary side capacitor C of a flyback transformer s Stabilized voltage sigma U on out As follows:
in the formula, sigma W 2 Is the energy obtained by the load in unit time; u shape omax An upper limit value for storing energy for a load end; eta is the discharge efficiency; vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is a time constant; t is time.
Example 10:
a non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor is mainly disclosed in embodiment 3, wherein a metal upper polar plate is connected with a high-voltage electrified body.
Claims (9)
1. A non-contact electric field optimization energy taking method suitable for self energy taking of a micro sensor is characterized by comprising the following steps:
1) And placing a non-contact electric field energy taking device in the alternating electric field.
The non-contact electric field energy taking device comprises a metal upper polar plate, a metal lower polar plate, a full-wave rectification bridge circuit and an energy storage capacitor C which are mutually parallel g The system comprises a high-frequency switch, a flyback transformer, an uncontrollable full-wave rectifier bridge, a micro-sensor module and a detection and control module;
the miniature sensor module is equivalent to a load ZL and comprises a signal acquisition circuit, a data processing circuit and a wireless communication circuit, wherein the signal acquisition circuit is electrically connected with the metal upper polar plate and the metal lower polar plate.
The detection and control module stores upper limit voltage V of a capacitor + Lower limit voltage V of capacitor - ；
2) The alternating current formed by the metal upper polar plate and the metal lower polar plate under the action of the electric field is transmitted to a full-wave rectification bridge circuit;
3) The full-wave rectification bridge circuit rectifies the alternating current into direct current for output and supplies the direct current to the energy storage capacitor C g Charging;
in the capacitor charging process, the detection and control module detects the energy storage capacitor C in real time g Voltage across the capacitor C g The voltage at both ends is greater than or equal to the upper limit voltage V + When the high-frequency switch is switched on, the detection and control module controls the high-frequency switch to be switched on, so that the energy storage capacitor C is enabled to be connected g The load Z is controlled by a flyback transformer and an uncontrollable full-wave rectifier bridge L Discharging;
in the capacitor discharging process, the detection and control module detects the energy storage capacitor C in real time g Voltage across, as energy storage capacitor C g The voltage at two ends is less than or equal to the lower limit voltage V of the capacitor - When the high-frequency switch is turned off, the detection and control module controls the high-frequency switch to be turned off, so that the metal upper polar plate and the metal lower polar plate are opposite to the energy storage capacitor C g And (6) charging.
2. The method of claim 1, wherein the self-energy-taking of the microsensor is achieved by a non-contact electric field optimized energy-taking methodCharacterized by an upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - Is in a preset range of [0.3V ] cc ，0.7V cc ](ii) a Vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation;
and the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - Simultaneously, the following requirements are met: 1) V + >V - ；2)V + -V - ≤0.5V cc 。
3. The non-contact electric field optimized energy taking method suitable for self energy taking of micro sensor as claimed in claim 1, wherein the energy storage capacitor C g The maximum value Vcc of the direct current voltage at two ends meets the following formula when the direct current voltage is saturated:
in the formula of U c For an energy-storage capacitor C g Monitoring values of voltages at two ends; t is time; τ is a time constant; vcc is energy storage capacitor C g The maximum value of the direct current voltage at two ends when the voltage is saturated.
4. The method for optimizing energy extraction of the micro-sensor through the non-contact electric field according to claim 1, wherein the upper limit voltage V of the capacitor is updated according to a discharge curve and a charge curve of the energy storage capacitor + Lower limit voltage V of capacitor - Comprises the following steps:
1) Determining the intersection point S after the translation of the discharge curve and the charge curve of the energy storage capacitor 1 ；
2) Determining the intersection point S 1 Corresponding voltage, denoted as V S ；
3) Determining the upper limit voltage V of the capacitor + Lower limit voltage V of capacitor - The constraint condition of (2): 1) V + ，V - ∈[-20％V S ，+20％V S ]；2)V + >V - ；3)V + -V - ≤V S ；
4) Determining the upper limit voltage V of the capacitor according to the constraint condition + Lower limit voltage V of capacitor - The value of (c).
5. The non-contact electric field optimized energy extraction method suitable for the self-energy extraction of the micro sensor according to claim 1, wherein the on-off frequency of the high-frequency switch is f, namely:
in the formula, vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is a time constant.
6. The method for optimizing energy extraction by using the non-contact electric field of the micro sensor as claimed in claim 1, wherein the energy storage capacitor C is used for extracting energy per unit time g Discharge energy
As follows:
in the formula, vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is a time constant.
7. The method as claimed in claim 1, wherein the load obtains energy ∑ W per unit time 2 As follows:
in the formula, eta is the discharge efficiency; vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is the time constant.
8. The method as claimed in claim 1, wherein the secondary side capacitance C of the flyback transformer is measured in unit time s Stabilized voltage sigma U on out As follows:
in the formula, sigma W 2 Is the energy obtained by the load in unit time; u shape omax An upper limit value for storing energy for a load end; eta is the discharge efficiency; vcc is energy storage capacitor C g Maximum value of direct current voltage at two ends during saturation; τ is a time constant; t is time.
9. The non-contact electric field optimized energy extraction method suitable for the self-energy extraction of the micro sensor according to claim 1, characterized in that: the metal upper polar plate is connected with the high-voltage charged body.
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