A non-contact electric field optimization energy harvesting method suitable for self-energy harvesting of micro sensors

Abstract

The present invention discloses a non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors, the steps comprising: 1) placing a non-contact electric field energy extraction device in an alternating electric field; 2) transmitting the alternating current formed by a metal upper plate and a metal lower plate under the action of the electric field to a full-wave rectifier bridge circuit; 3) the full-wave rectifier bridge circuit rectifies the alternating current into a direct current output, and performs a direct current on an energy storage capacitor C g Charging; the detection and control module controls the high-frequency switch to turn on the energy storage capacitor C g Through the flyback transformer, uncontrolled full-wave rectifier bridge to load Z L Discharge; The present invention proposes a non-contact electric field coupling energy collection method suitable for self-energy collection of micro sensors. Combined with the energy collection calculation, a suitable energy collection approximate estimation method is proposed and an energy and voltage optimization scheme for the energy collection process is given. An external power supply is no longer required, thereby providing the sensor with stable voltage and power, ensuring the normal operation and measurement of the electric field sensor.

Description

Technical Field

[0001] The invention relates to the field of online detection of electric power systems, and in particular to a non-contact electric field optimization energy acquisition method suitable for self-energy acquisition of micro sensors. Background Art

[0002] With the construction of smart grids, a large number of low-power electric field sensors and online monitoring devices are applied to the power grid to obtain key data information on the operation of the power grid. When measuring the electric field strength, the sensor often needs to be in a high-energy electromagnetic environment, so how to power the electric field sensor has become a new technical difficulty. There are currently two main ways to obtain energy: transmission power supply and autonomous energy supply. The transmission power supply method mainly transmits energy from the ground to the online measuring device through optical fiber or microwave. The main disadvantage of this energy supply method is that it is expensive and not suitable for large-scale popularization. Therefore, self-energy supply is the main development direction of electric field sensors.

[0003] At the same time, electric field sensors have gradually tended to be miniaturized and self-powered in recent years, but the related theoretical research still cannot meet the needs of practical applications. Common self-powered methods include battery, solar energy, piezoelectric material vibration energy, wind energy, magnetic induction, temperature difference energy, etc. The battery method requires regular power outages for replacement; solar or wind energy is highly random and easily affected by environmental factors; magnetic induction energy is affected by unstable load current, and cannot work normally when the line is out of power, there is a large power supply blind area, and it is difficult to ensure the stability of power supply; other methods are limited by natural conditions, which will also affect the stability of power supply. Compared with other self-powered methods, the electric field coupling energy supply method is easier to implement based on the electric field environment. The voltage self-powered power supply is studied to power the electric field sensor and achieve a balance between supply and demand, so as to achieve energy consumption on one side and self-powered power on the other side, so as to achieve the purpose of self-sufficiency of the closed system.

[0004] Compared with conventional electric field energy harvesting, the electric field energy harvesting method suitable for micro sensors has more stringent requirements: 1. Sensor miniaturization requires that the metal plates for electric field sensing be smaller in size and closer in distance; 2. The power and voltage provided are lower. In comparison, the general power requirement of the load is in the mW level, and the voltage requirement is around 3 to 15V; 3. The energy harvesting efficiency requirements are higher and the loss requirements are less. The circuit should be simplified as much as possible to reduce the size of the energy harvesting circuit.

[0005] In order to meet the above requirements, some scholars have proposed an alternating electric field energy harvesting circuit, including a high-potential conductor, an induction electrode-to-ground capacitor and an energy harvesting capacitor. One end of the energy harvesting capacitor is connected to the high-potential conductor, and the other end of the energy harvesting capacitor is grounded after passing through the induction electrode-to-ground capacitor. The energy harvesting circuit and self-excited power supply can achieve stable energy harvesting and power supply. However, this circuit does not take into account the potential power loss, requires a large number of MOS tubes, and cannot guarantee that energy is released every time at the peak of energy storage, resulting in reduced efficiency in practical applications. The voltage and power that can be provided to the sensor are relatively small. At the same time, the metal electrode is relatively large in size and is not suitable for the energy harvesting needs of micro electric field sensors. Other scholars have proposed a space electric field energy harvesting device, which can directly power low-power automated monitoring or communication equipment at the low potential of the space electric field, and can also use energy storage devices to power high-power intermittent equipment. However, due to its limited applicable voltage level, a large number of capacitor banks are required, which increases the cost; due to the weak electric field strength, the magnitude of self-extracted energy is far less than that of high-voltage strong electric fields, and thus it can only be used for micro sensors with low energy consumption and low voltage levels; due to the possible presence of a certain resistance during the operation of the device, the resonant energy consumption will lead to a further reduction in the energy obtained, and the applicable conditions will be more stringent. Summary of the invention

[0006] The object of the present invention is to provide a non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors, comprising the following steps:

[0007] 1) Placing the non-contact electric field energy extraction device in an alternating electric field; the non-contact electric field energy extraction device comprises a mutually parallel metal upper plate, a metal lower plate, a full-wave rectifier bridge circuit, and an energy storage capacitor C g , high frequency switch, flyback transformer, uncontrollable full-wave rectifier bridge, micro sensor module, detection and control module; the micro sensor module is equivalent to load Z L , including a signal acquisition circuit, a data processing circuit, and a wireless communication circuit electrically connected to the metal upper plate and the metal lower plate;

[0008] The detection and control module stores the capacitor upper limit voltage V + , capacitor lower limit voltage V - ;

[0009] 2) Transmitting the alternating current formed by the metal upper plate and the metal lower plate under the action of the electric field to the full-wave rectifier bridge circuit;

[0010] 3) The full-wave rectifier bridge circuit rectifies the AC power into DC output and supplies the energy storage capacitor C g Charge;

[0011] During the capacitor charging process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends isg The voltage across the two ends is greater than or equal to the upper limit voltage V + When the detection and control module controls the high-frequency switch to conduct, the energy storage capacitor C g Through the flyback transformer, uncontrolled full-wave rectifier bridge to load Z L Discharge;

[0012] During the capacitor discharge process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends is g The voltage across the capacitor is less than or equal to the lower limit voltage V - When the detection and control module controls the high-frequency switch to be disconnected, the metal upper plate and the metal lower plate are connected to the energy storage capacitor C g Charge;

[0013] Furthermore, the upper limit voltage of the capacitor V + , capacitor lower limit voltage V - The preset range is [0.3V cc , 0.7V cc ]; Vcc is the energy storage capacitor C g The maximum DC voltage across the two ends when saturated;

[0014] And the upper limit voltage of the capacitor V + , capacitor lower limit voltage V - At the same time: 1) V + >V - ; 2) V + -V - ≤0.5V cc .

[0015] Furthermore, the energy storage capacitor C g When saturated, the maximum DC voltage Vcc at both ends satisfies the following formula:

[0016]

[0017]

[0018] Where U c is the energy storage capacitor C g The monitored value of the voltage at both ends; t is the time; τ is the time constant.

[0019] Further, the capacitor upper limit voltage V is updated according to the energy storage capacitor discharge curve and charging curve. + , capacitor lower limit voltage V - The steps include:

[0020] a) Determine the intersection point S1 of the energy storage capacitor discharge curve and the charging curve after translation;

[0021] b) Determine the voltage corresponding to the intersection S1, denoted as VS ;

[0022] c) Determine the upper limit voltage V of the capacitor + , capacitor lower limit voltage V - Constraints: 1) V + , V - ∈[-20%V S , +20%V S ]; 2) V + >V - ; 3) V + -V - ≤V S ;

[0023] d) Determine the upper limit voltage V of the capacitor according to the constraints + , capacitor lower limit voltage V - The value of .

[0024] Furthermore, the on-off frequency of the high-frequency switch is f, that is:

[0025]

[0026] Furthermore, per unit time, the energy storage capacitor C g Discharge energy As shown below:

[0027]

[0028] Furthermore, the energy ∑W2 obtained by the load per unit time is as follows:

[0029]

[0030] Where η is the discharge efficiency.

[0031] Furthermore, per unit time, the secondary side capacitor C of the flyback transformer s The stable voltage ∑U out As shown below:

[0032]

[0033] In the formula, ∑W2 is the energy obtained by the load per unit time; U omax It is the upper limit of energy storage at the load end.

[0034] Furthermore, the metal upper plate is connected to a high voltage charged body.

[0035] The technical effect of the present invention is unquestionable. The present invention proposes a non-contact electric field coupling energy collection method suitable for self-energy collection of micro sensors. Combined with the energy collection calculation, a suitable energy collection approximate estimation method is proposed and an energy and voltage optimization scheme for the energy collection process is given. An external power supply is no longer required, thereby providing the sensor with stable voltage and power, ensuring the normal operation and measurement of the electric field sensor.

[0036] The present invention can meet the special requirements of micro electric field sensors for small size, low power, low voltage and low loss, proposes an energy acquisition process and theoretical calculation of the energy and voltage obtained by the method, can meet the energy consumption requirements of micro sensors in a high voltage environment, and can help achieve power consumption balance of electric field sensors.

[0037] The present invention proposes an energy and voltage optimization scheme and a practical approximate estimation method for the energy extraction process, which greatly improves the efficiency of the sensor's self-power supply, and can quickly calculate and analyze in engineering, summarizes the key factors affecting the energy extraction efficiency, and clarifies the direction for the main contents of the subsequent practical application, optimization adjustment, and experimentation of micro electric field sensor engineering.

[0038] The present invention is suitable for self-energy extraction of micro electric field sensors. The components involved are relatively simple, easy to obtain, and low in cost. Compared with the traditional electric field energy extraction method, it greatly saves space and materials. This method has fewer external restrictions and can work under high-voltage alternating electric field conditions. The time required from the first capacitor energy storage to the final voltage stabilization is short, and it can work quickly and stably, so it has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of a method for self-energy extraction of a micro electric field sensor;

[0040] Figure 2 is the energy storage capacitor C g Energy extraction optimization and approximate estimation. DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with the embodiments, but it should not be understood that the above subject matter of the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various substitutions and changes are made according to the common technical knowledge and customary means in the art, which should all be included in the protection scope of the present invention.

[0042] Embodiment 1:

[0043] See also Figure 1 to Figure 2 A non-contact electric field optimization energy extraction method suitable for micro sensor self-energy extraction includes the following steps:

[0044] 1) Placing the non-contact electric field energy extraction device in an alternating electric field; the non-contact electric field energy extraction device comprises a mutually parallel metal upper plate, a metal lower plate, a full-wave rectifier bridge circuit, and an energy storage capacitor C g , high frequency switch, flyback transformer, uncontrolled full-wave rectifier bridge, micro sensor module (equivalent to load Z L ), detection and control module;

[0045] The micro sensor module includes a signal acquisition circuit, a data processing circuit, a wireless communication circuit, etc. connected to the metal plate;

[0046] The detection and control module stores the capacitor upper limit voltage V + , capacitor lower limit voltage V - ;

[0047] 2) Transmitting the alternating current formed by the metal upper plate and the metal lower plate under the action of the electric field to the full-wave rectifier bridge circuit;

[0048] 3) The full-wave rectifier bridge circuit rectifies the AC power into DC output and supplies the energy storage capacitor C g Charge;

[0049] During the capacitor charging process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends is g The voltage across the two ends is greater than or equal to the upper limit voltage V + When the detection and control module controls the high-frequency switch to conduct, the energy storage capacitor C g Through the flyback transformer, uncontrolled full-wave rectifier bridge to load Z L discharge;

[0050] During the capacitor discharge process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends is g The voltage across the capacitor is less than or equal to the lower limit voltage V - When the detection and control module controls the high-frequency switch to be disconnected, the metal upper plate and the metal lower plate are connected to the energy storage capacitor C g Charge;

[0051] Capacitor upper limit voltage V + , capacitor lower limit voltage V - The preset range is [0.3V cc , 0.7V cc ]; Vcc is the energy storage capacitor C g The maximum DC voltage across the two ends when saturated;

[0052] And the upper limit voltage of the capacitor V + , capacitor lower limit voltage V - At the same time: 1) V+ >V - ; 2) V + -V - ≤0.5V cc .

[0053] Energy storage capacitor C g When saturated, the maximum DC voltage Vcc at both ends satisfies the following formula:

[0054]

[0055]

[0056] Where U c is the energy storage capacitor C g The monitored value of the voltage at both ends; t is the time; τ is the time constant.

[0057] Update the capacitor upper limit voltage V according to the energy storage capacitor discharge curve and charging curve + , capacitor lower limit voltage V - The steps include:

[0058] a) Determine the intersection point S1 of the energy storage capacitor discharge curve and the charging curve after translation;

[0059] b) Determine the voltage corresponding to the intersection S1, denoted as V S ;

[0060] c) Determine the upper limit voltage V of the capacitor + , capacitor lower limit voltage V - Constraints: 1) V + , V - ∈[-20%V S , +20%V S ]; 2) V + >V - ; 3) V + -V - ≤V S ;

[0061] d) Determine the upper limit voltage V of the capacitor according to the constraints + , capacitor lower limit voltage V - The value of .

[0062] The on-off frequency of the high-frequency switch is f, that is:

[0063]

[0064] In unit time, the energy storage capacitor C g Discharge energy As shown below:

[0065]

[0066] The energy ∑W2 obtained by the load per unit time is as follows:

[0067]

[0068] Where η is the discharge efficiency.

[0069] In unit time, the secondary side capacitance C of the flyback transformer s The stable voltage ∑U out As shown below:

[0070]

[0071] In the formula, ∑W2 is the energy obtained by the load per unit time; U omax It is the upper limit of energy storage at the load end.

[0072] The metal upper electrode plate is connected to a high voltage charged body.

[0073] Compared with the general electric field coupling energy collection method, the micro electric field sensor self-collection requires small size, low power, low voltage, and low loss, so it cannot directly adopt the traditional metal electrode electric field induction-rectification filtering-energy storage and release method. The size of the metal plate must be limited to 0.1m×0.1m, the induction plate is externally connected to a full-wave rectifier bridge circuit, and the diode power consumption is required to be minimal, converting the alternating voltage into a DC voltage V cc After that, through the energy storage capacitor C g Energy storage. Since the metal plate of the micro electric field sensor is small, the voltage obtained is proportional to the plate area. Even at a higher voltage level, the voltage can be directly transferred through C g The energy obtained is also at the microwatt level, which is not enough to reach the milliwatt level of the sensor itself. Therefore, by using high-frequency switches and voltage monitoring circuits, when the capacitor voltage reaches a certain threshold, the circuit can be monitored and turned on to drive the energy storage capacitor C g Release energy; when the capacitor voltage drops to a certain threshold, monitor and shut down the circuit to make the energy storage capacitor C g Energy storage can be achieved by using the secondary side energy storage capacitor C of the flyback transformer. s The pumping effect of the metal plate can obtain more energy, and at the same time promote the flow of induced charge on the metal plate, thereby improving the efficiency of energy collection and solving the problem of insufficient power of traditional direct electric field energy collection. The method of selecting the threshold will greatly affect the final energy collection efficiency, so it must be deduced. The flyback transformer has a small number of turns and low loss, which can effectively raise the primary voltage. After full-wave rectification, it can provide a stable power supply voltage for the load, solving the pain point of low voltage of the micro electric field sensor.

[0074] Embodiment 2:

[0075] A non-contact electric field optimization energy harvesting method suitable for self-energy harvesting of micro sensors, comprising the following contents:

[0076] Assume that the effective value of the metal plate alternating voltage is U1, and after passing through the full-wave rectifier bridge circuit, the energy storage capacitor C g The maximum DC voltage at both ends when saturated is Vcc, and the time-varying monitoring value is U c , secondary side energy storage capacitor C s , the electric field sensor load is equivalent to Z L Since the power supply voltage of online monitoring equipment such as micro electric field sensors is generally not high (usually 3V-15V), and the working energy consumption is at the milliwatt level, C g The size of the energy storage is very important. It not only needs to consider the energy consumption and the required voltage, but also the time of energy storage and energy release.

[0077]

[0078]

[0079] The charging (discharging) process of the capacitor is nonlinear. When the capacitor voltage reaches a certain threshold, the upper limit voltage V + , transmits a signal to the detection circuit, when it detects that the upper limit voltage V + , control the switch to conduct, so that the capacitor discharges until the voltage across the capacitor drops to the lower limit voltage V - , at this time the switch is disconnected and the capacitor re-stores energy.

[0080] U c ≥V + Switch on

[0081] U c ≤V - Switch cut-off

[0082] Assume that t1 and t2 are the charging and discharging times in a cycle T, respectively. The voltage on both sides of the energy-collecting capacitor is always V + and V - The energy delivered to the discharge circuit in each cycle is

[0083]

[0084] Assume that the switch is turned on and off f times within 1s, that is, the switching frequency is f, then the cumulative transmission energy within 1s is

[0085]

[0086] Due to C g As a constant, we find that f exists with V + and V -Negative correlation, specifically when ΔU=V + -V - When the voltage is reduced, the time for the capacitor to charge and discharge will be reduced, and the frequency f will increase. Therefore, the functional relationship between them is very important and affects the effect of optimizing energy extraction. Since the charging voltage range of the capacitor is [0, Vcc], the charging time of the capacitor is t1, the discharging time is t2, and the switching frequency is f:

[0087]

[0088]

[0089] The capacitor charge and discharge cycle is T, and (7)

[0090]

[0091] From this we can get the switching frequency f

[0092]

[0093] From equation (8), it can be seen that when the time constant τ and the maximum charging voltage V cc Under certain conditions, the value of f is determined by the threshold voltage. Substituting this formula into formula (4), the energy obtained per unit time is (9)

[0094]

[0095] When the energy passes through the flyback transformer to the load end, the equivalent load on the secondary side of the transformer is Z L , the efficiency of the discharge circuit is η, then the energy obtained by the load per unit time (1s) is (10):

[0096]

[0097] Assuming the working time of the energy-harvesting circuit is ts, the total power obtained during this period is

[0098]

[0099] Converted to secondary side capacitance C s The stable voltage U out

[0100]

[0101] It can be seen from the subsequent simulation that if the load end is always storing energy, U out It rises continuously in a step waveform within t until the upper limit of the energy storage at the load end is reached.

[0102]

[0103] It can be seen that by reasonably designing the on-off frequency of the switch and the relevant parameters of the transformer, especially C g 、V + and V - , can achieve the goal of continuously delivering energy to the load end, and theoretically the energy W2 delivered per unit time and the output voltage U out It is basically constant, which can meet the requirements of small size, low power, low voltage and low loss for micro electric field sensors.

[0104] From the above analysis, we can see that V + and V - The determination of is particularly important for the energy extraction process, and is also an important parameter that affects the energy (Equation 11) and voltage (Equation 13). Therefore, based on the cut-and-fill method and the integral median theorem, V can be determined. + and V - The approximate value of and approximate estimate of energy and voltage. Figure 1 Demonstrates the energy storage capacitor C g Energy approximate estimation method:

[0105] First, make sure V + and V - The selection hidden condition: First, if V + and V - If the gap is too large, the charging and releasing time in one cycle will be too long, which will greatly reduce the efficiency. + and V - The gap is too small. Although the charging and discharging time in a cycle is reduced, the energy obtained in the cycle is also greatly reduced, and the efficiency is also reduced. Third, the slope of the charge and discharge curve is from infinity to 0. If V + and V - If the value is smaller or larger at the same time, the charging time t1 and the releasing time t2 will be shorter or longer. Therefore, the following two conclusions can be drawn: 1) V + and V - The gap should be moderate, at least less than 0.5V cc 2)V + and V - Neither can be too large or too small to ensure that the slopes of the energy extraction and release process function curves reach the maximum as much as possible at the same time.

[0106] Based on the above two conclusions, the intersection of the charge and discharge curves after translation is selected as the reference point S1. The voltage corresponding to the reference point S1 is exactly 0.5V. cc , the charge and discharge curve after translation is about 0.5V cc Axis symmetry. + and V -When, not only about 0.5V cc Axis symmetry, while trying to meet the S1 corresponding voltage ± 20% range, that is, 0.3V cc -0.7V cc .

[0107] By selection As an example, we further analyze the practical approximate estimation method. + Intersects with the charge and discharge curve at A and B respectively; V - The charge and discharge curves intersect at C and D respectively; arc AB intersects arc CD at S1; AB intersects CD at S2. For the convenience of power estimation, two triangles △BCD and △ACD in the rectangle ABCD with S2 as the center are used to approximate the capacitor charge and discharge process. The actual error is only twice the area of ​​the figure enclosed by arc AB and AB. The reasons for this simplification are: first, the power obtained by the micro electric field sensor itself is small, so the estimation error can be ignored; second, the selected V + and V - This is quite reasonable. The slopes of arc AB and arc CD are large, and the rate of change of the slope is small, so they can be turned into straight lines. Therefore, they can be ignored in power estimation. Therefore, when approximating power estimation, the capacitor C can be replaced by an isosceles triangle sawtooth wave. g Substituting the charge and discharge process into formula (9) yields the energy taken within time t:

[0108]

[0109] From the cut-and-fill method, we know that the area of ​​the figure enclosed by arcs AB and AB is equal to the area of ​​the figure enclosed by arcs CD and CD. The voltage can be directly estimated by the integral mean value theorem:

[0110]

[0111]

[0112] Since t1 and t2 are equal, the average voltage is 0.5V cc Assuming the flyback transformer ratio is k, the voltage across the load after full-wave rectification on the secondary side is U L :

[0113] U L =0.45kV CC (17)

[0114] Therefore, based on this approximate calculation method, as long as the parameters such as the effective value of the metal plate alternating voltage U1, the working time t, and the transformation ratio k are obtained, the energy and average voltage of the micro electric field sensor can be quickly estimated according to equations (14) and (17). + and V- The determination solves the problem of small metal plates and low energy efficiency of micro electric field sensors for self-energy extraction, and meets the three requirements for self-energy extraction.

[0115] Analysis of the main factors affecting the self-energy efficiency and voltage of micro electric field sensors:

[0116] 1)U1(V cc ):According to equations (14) and (17), the voltage U1 (V cc ) The higher the level, the greater the corresponding self-energy and voltage. Therefore, it can be concluded that an environment with a higher voltage level is more conducive to the self-energy extraction of micro electric field sensors.

[0117] 2) C g Influence: From the formula, it can be seen that when C is selected g When the capacitor is connected in parallel, a larger capacitance value can be obtained. The essence of the discharge circuit is a second-order oscillation circuit. Energy is transferred back and forth between the transformer inductance and the energy-taking capacitor. Therefore, the control switch is at V - It is turned off to prevent the current from flowing back to the capacitor, so that the energy is transferred to the secondary side. g Smaller, while C s Large, resulting in oscillation angular frequency ω r Very small, s Relatively large. Therefore, it is necessary to ensure that the primary side capacitance C g The time required to transfer energy to the flyback transformer is much shorter than C g Charging time, secondary side capacitor C s The charging time should be less than C g Charging time is relatively difficult. g If a capacitor that is too large is used, the withstand voltage will not be high and will have an upper limit, making it difficult to further increase the voltage.

[0118] 3) Z L Influence of: Z L Refers to the load connected to the self-powered sensor, that is, the impedance of the circuits such as the micro electric field sensor acquisition module, data processing module, and wireless module. As can be seen from the formula, the load Z L The increase is conducive to stabilizing the voltage U s But Z L After increasing to a certain extent, U s The rate of change is much smaller than the rate of change of the load, which may result in the inability to provide a voltage that satisfies the load operation. Therefore, when actually adjusting the load, try to satisfy the supply voltage first, and then increase the load appropriately.

[0119] 4) V + and V -Impact: Regardless of V + Too large or V - Too small may lead to a decrease in energy efficiency. + and V - The gap should be moderate, at least less than 0.5V cc . V + and V - should not be too large or too small to ensure that the slope of the energy extraction and release process function curves can reach the maximum value at the same time. + and V - When, not only about 0.5V cc Axis symmetry, while trying to meet the S1 corresponding voltage ± 20% range, that is, 0.3V cc -0.7V cc .

[0120] 5) Influence of η: The loss of self-energy extraction of micro electric field sensors mainly comes from two aspects: component loss and switch loss. The existing high-frequency switching technology is already very mature, so the main task is to control the relationship between the frequency of switch power-on and the charging and discharging power of the capacitor. Because the current flowing through each component is small under high voltage environment, the component loss mainly depends on the voltage of the use environment. Therefore, in order to reduce component loss, this method is more suitable for self-energy extraction under high voltage.

[0121] Embodiment 3:

[0122] A non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors, comprising the following steps:

[0123] 1) Placing the non-contact electric field energy extraction device in an alternating electric field; the non-contact electric field energy extraction device comprises a mutually parallel metal upper plate, a metal lower plate, a full-wave rectifier bridge circuit, and an energy storage capacitor C g , 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 sensor module is equivalent to a load ZL, including a signal acquisition circuit, a data processing circuit, and a wireless communication circuit electrically connected to a metal upper plate and a metal lower plate;

[0124] The detection and control module stores the capacitor upper limit voltage V + , capacitor lower limit voltage V - ;

[0125] 2) Transmitting the alternating current formed by the metal upper plate and the metal lower plate under the action of the electric field to the full-wave rectifier bridge circuit;

[0126] 3) The full-wave rectifier bridge circuit rectifies the AC power into DC output and supplies the energy storage capacitor C g Charge;

[0127] During the capacitor charging process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends is g The voltage across the two ends is greater than or equal to the upper limit voltage V + When the detection and control module controls the high-frequency switch to conduct, the energy storage capacitor C g Through the flyback transformer, uncontrolled full-wave rectifier bridge to load Z L Discharge;

[0128] During the capacitor discharge process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends is g The voltage across the capacitor is less than or equal to the lower limit voltage V - When the detection and control module controls the high-frequency switch to be disconnected, the metal upper plate and the metal lower plate are connected to the energy storage capacitor C g Charge.

[0129] Embodiment 4:

[0130] A non-contact electric field optimization energy extraction method suitable for micro sensor self-energy extraction, the main content of which is shown in Example 3, wherein the capacitor upper limit voltage V + , capacitor lower limit voltage V - The preset range is [0.3V cc , 0.7V cc ]; Vcc is the energy storage capacitor C g The maximum DC voltage across the two ends when saturated;

[0131] And the upper limit voltage of the capacitor V + , capacitor lower limit voltage V - At the same time: 1) V + >V - ; 2) V + -V - ≤0.5V cc .

[0132] Embodiment 4:

[0133] A non-contact electric field optimization energy extraction method suitable for micro sensor self-energy extraction, the main content of which is shown in Example 3, wherein the energy storage capacitor C g When saturated, the maximum DC voltage Vcc at both ends satisfies the following formula:

[0134]

[0135]

[0136] Where U c is the energy storage capacitor C gThe monitored value of the voltage at both ends; t is the time; τ is the time constant; Vcc is the energy storage capacitor C g The maximum DC voltage across the terminals when saturated.

[0137] Embodiment 5:

[0138] A non-contact electric field optimization energy extraction method suitable for micro sensor self-energy extraction, the main content of which is shown in Example 3, wherein the capacitor upper limit voltage V is updated according to the discharge curve and charging curve of the energy storage capacitor + , capacitor lower limit voltage V - The steps include:

[0139] 1) Determine the intersection point S1 of the energy storage capacitor discharge curve and the charging curve after translation;

[0140] 2) Determine the voltage corresponding to the intersection S1, recorded as V S ;

[0141] 3) Determine the upper limit voltage V of the capacitor + , capacitor lower limit voltage V - Constraints: 1) V + , V - ∈[-20%V S , +20%V S ]; 2) V + >V - ; 3) V + -V - ≤V S ;

[0142] 4) Determine the upper limit voltage V of the capacitor according to the constraints + , capacitor lower limit voltage V - The value of .

[0143] Embodiment 6:

[0144] A non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors, the main content of which is shown in Example 3, wherein the on-off frequency of the high-frequency switch is f, that is:

[0145]

[0146] Where Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant.

[0147] Embodiment 7:

[0148] A non-contact electric field optimization energy extraction method suitable for micro sensor self-energy extraction, the main content of which is shown in Example 3, wherein the energy storage capacitor C g Discharge energy As shown below:

[0149]

[0150] Where Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant.

[0151] Embodiment 8:

[0152] A non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors, the main content of which is shown in Example 3, wherein the energy ∑W2 obtained by the load per unit time is as follows:

[0153]

[0154] Where η is the discharge efficiency; Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant.

[0155] Embodiment 9:

[0156] A non-contact electric field optimization energy extraction method suitable for micro sensor self-energy extraction, the main content of which is shown in Example 3, wherein per unit time, the secondary side capacitor C of the flyback transformer s The stable voltage ∑U out As shown below:

[0157]

[0158] In the formula, ∑W2 is the energy obtained by the load per unit time; U omax is the upper limit of energy storage at the load end; η is the discharge efficiency; Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant; t is the time.

[0159] Embodiment 10:

[0160] A non-contact electric field optimized energy extraction method suitable for self-energy extraction of micro sensors, the main content of which is shown in Example 3, wherein the metal upper electrode plate is connected to a high-voltage charged body.

Claims

1. A non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors, characterized in that: The following steps are involved: 1) Placing the non-contact electric field energy harvesting device in an alternating electric field; The non-contact electric field energy harvesting device includes a metal upper plate and a metal lower plate parallel to each other, a full-wave rectifier bridge circuit, and an energy storage capacitor C g , high frequency switch, flyback transformer, uncontrollable full-wave rectifier bridge, micro sensor module, detection and control module; The micro sensor module is equivalent to a load ZL, and includes a signal acquisition circuit, a data processing circuit, and a wireless communication circuit electrically connected to the metal upper plate and the metal lower plate; The detection and control module stores the capacitor upper limit voltage V + , capacitor lower limit voltage V - ; 2) Transmitting the alternating current formed by the metal upper plate and the metal lower plate under the action of the electric field to the full-wave rectifier bridge circuit; 3) The full-wave rectifier bridge circuit rectifies the AC power into DC output and supplies the energy storage capacitor C g Charge; During the capacitor charging process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends is g The voltage across the two ends is greater than or equal to the upper limit voltage V + When the detection and control module controls the high-frequency switch to conduct, the energy storage capacitor C g Through the flyback transformer, uncontrolled full-wave rectifier bridge to load Z L Discharge; During the capacitor discharge process, the detection and control module detects the energy storage capacitor C in real time. g The voltage across the two ends is g The voltage across the capacitor is less than or equal to the lower limit voltage V - When the detection and control module controls the high-frequency switch to be disconnected, the metal upper plate and the metal lower plate are connected to the energy storage capacitor C g Charge.

2. According to claim 1, a non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors is characterized in that: Capacitor upper limit voltage V + , capacitor lower limit voltage V - The preset range is [0.3V cc , 0.7V cc ]; Vcc is the energy storage capacitor C g The maximum DC voltage across the two ends when saturated; And the upper limit voltage of the capacitor V + , capacitor lower limit voltage V - At the same time: 1) V + >V - ; 2) V + -V - ≤0.5V cc .

3. According to claim 1, a non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors is characterized in that: Energy storage capacitor C g When saturated, the maximum DC voltage Vcc at both ends satisfies the following formula: Where U c is the energy storage capacitor C g The monitored value of the voltage at both ends; t is the time; τ is the time constant; Vcc is the energy storage capacitor C g The maximum DC voltage across the terminals when saturated.

4. The non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors according to claim 1, characterized in that: Update the capacitor upper limit voltage V according to the energy storage capacitor discharge curve and charging curve + , capacitor lower limit voltage V - The steps include: 1) Determine the intersection point S1 of the energy storage capacitor discharge curve and the charging curve after translation; 2) Determine the voltage corresponding to the intersection S1, recorded as V S ; 3) Determine the upper limit voltage V of the capacitor + , capacitor lower limit voltage V - Constraints: 1) V + , V - ∈[-20%V S , +20%V S ]; 2) V + >V - ; 3) V + -V - ≤V S ; 4) Determine the upper limit voltage V of the capacitor according to the constraints + , capacitor lower limit voltage V - The value of .

5. The non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors according to claim 1, characterized in that: The on-off frequency of the high-frequency switch is f, that is: Where Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant.

6. The non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors according to claim 1, characterized in that: In unit time, the energy storage capacitor C g Discharge energy As shown below: Where Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant.

7. The non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors according to claim 1, characterized in that: The energy ∑W2 obtained by the load per unit time is as follows: Where η is the discharge efficiency; Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant.

8. The non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors according to claim 1, characterized in that: In unit time, the secondary side capacitance C of the flyback transformer s The stable voltage ∑U out As shown below: In the formula, ∑W2 is the energy obtained by the load per unit time; U omax is the upper limit of energy storage at the load end; η is the discharge efficiency; Vcc is the energy storage capacitor C g The maximum value of the DC voltage at both ends when saturated; τ is the time constant; t is the time.

9. The non-contact electric field optimization energy extraction method suitable for self-energy extraction of micro sensors according to claim 1, characterized in that: The metal upper electrode plate is connected to a high voltage charged body.

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