Non-intrusive magnetic energy collecting device for maximum power point tracking

Abstract

The invention provides a non-intrusive magnetic energy collection device for maximum power point tracking, which belongs to the technical field of magnetic energy collection, and comprises a magnetic core, a sampling module, a power supply module and an energy taking module, wherein three layers of coils are arranged on the magnetic core, the sampling coil is arranged on the innermost layer, the power supply coil is clamped between the sampling coil and the energy taking coil, and the energy taking coil is arranged on the outermost layer. The positive output end of the energy taking module is connected with the positive electrode of the load, the negative output end of the energy taking module is connected with the negative electrode of the load, and the first input end of a maximum power point tracking submodule in the energy taking module is connected with the output end of the sampling module. The power supply input end of the maximum power point tracking sub-module is connected with the output end of the power supply module; therefore, the non-intrusive magnetic energy collecting device disclosed by the invention can be applied to many scenes in which an external power supply cannot be additionally arranged, and the defect of low practicability of a non-intrusive magnetic energy collecting device with a maximum power tracking function in the prior art is overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic energy collection, and in particular to a non-invasive magnetic energy collection device for maximum power point tracking. Background Art

[0002] Non-invasive magnetic energy harvesting devices, based on the principle of electromagnetic induction, can convert ambient magnetic field energy into electrical energy to power downstream loads. Because the magnetic core is non-closed, non-invasive magnetic energy harvesting devices can be flexibly installed in locations where AC magnetic fields exist within the power grid, allowing for a wide range of applications. Furthermore, they offer advantages such as weather resistance, small size, and low cost. However, in practical applications, the electrical energy output of non-invasive magnetic energy harvesting devices requires internal energy management processes such as rectification, energy storage, and DC-DC conversion to power the sensor. Therefore, the output of non-invasive magnetic energy harvesting devices often deviates from their maximum power point.

[0003] In order to achieve adaptive maximum power tracking of energy harvesting in a non-invasive magnetic energy harvesting device, the prior art proposes to use a linear extrapolation method to determine the open-circuit voltage peak value, which achieves the goal of measuring the open-circuit voltage peak value without interrupting the circuit, and on this basis, uses the fractional voltage method to determine the maximum power point; however, this solution uses an MSP430 microcontroller to adjust the duty cycle to obtain the value corresponding to the maximum power point in order to achieve the linear extrapolation method, but driving the microcontroller consumes more power and requires an external power supply. However, this device is usually used in scenarios such as power grids and tracks where it is not easy to add an external power supply. Therefore, in the prior art, the non-invasive magnetic energy harvesting device with a maximum power tracking function has the defect of low practicality. Summary of the Invention

[0004] The present invention provides a non-invasive magnetic energy collection device with maximum power point tracking, which can overcome the defect of low practicality of non-invasive magnetic energy collection devices with maximum power point tracking function in the prior art.

[0005] A non-invasive magnetic energy collection device for maximum power point tracking, characterized by comprising: a magnetic core, a sampling module, a power supply module, and an energy extraction module; wherein the sampling module comprises: a sampling coil wound around the magnetic core; the power supply module comprises: a power supply coil wound around the outer layer of the sampling coil; the energy extraction module comprises: an energy extraction coil wound around the outer layer of the power supply coil, a first rectifier bridge, and a maximum power point tracking submodule; wherein the number of turns of the energy extraction coil is greater than that of the sampling coil and the power supply coil;

[0006] The positive output terminal of the energy acquisition module is connected to the positive electrode of the load, the negative output terminal of the energy acquisition module is connected to the negative electrode of the load, the first input terminal of the maximum power point tracking submodule in the energy acquisition module is connected to the output terminal of the sampling module, and the power supply input terminal of the maximum power point tracking submodule is connected to the output terminal of the power supply module;

[0007] The sampling module is configured to use the sampling coil to sense the induced magnetic field generated by the energy extraction coil to generate a reference voltage;

[0008] The power supply module is used to use the power supply coil to induce the induced magnetic field generated by the energy extraction coil to provide electrical energy to the energy extraction module;

[0009] The energy acquisition module is used to use the energy acquisition coil to sense the ambient magnetic field to generate an AC induced voltage, and use the first rectifier bridge to convert the AC induced voltage into a DC output voltage. The maximum power point tracking submodule is used to determine the target voltage value range required to output maximum power under the ambient magnetic field based on the reference voltage, and regulate the DC output voltage based on the target voltage value range.

[0010] Furthermore, the windings of the energy extraction coil are in a regular hexagonal stacking structure.

[0011] Furthermore, the sampling module further includes: a diode, a first capacitor, a first resistor and a second resistor;

[0012] The positive electrode of the sampling coil is connected to the positive electrode of the diode, the negative electrode of the diode is connected to the first end of the first capacitor, the first end of the first capacitor is connected to the first end of the first resistor, the second end of the first capacitor is connected to the negative electrode of the sampling coil, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the second end of the first capacitor, and the second end of the second resistor is grounded. The first end of the second resistor serves as the output end of the sampling module.

[0013] Furthermore, the power supply module further includes: a second capacitor, a second rectifier bridge, a linear regulator, a first stabilizing capacitor and a second stabilizing capacitor;

[0014] The positive pole of the power supply coil is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first AC input end of the second rectifier bridge, the second AC input end of the second rectifier bridge is connected to the negative pole of the power supply coil, the negative DC output end of the second rectifier bridge is grounded, the positive DC output end of the second rectifier bridge is connected to the first end of the first voltage-stabilizing capacitor, the first end of the first voltage-stabilizing capacitor is connected to the input end of the linear regulator, the output end of the linear regulator is connected to the first end of the second voltage-stabilizing capacitor, the second end of the first voltage-stabilizing capacitor is grounded, the second end of the second voltage-stabilizing capacitor is grounded, and the output end of the linear regulator is the output end of the power supply module.

[0015] Furthermore, the energy acquisition module further includes: a third capacitor, a filter capacitor, a first voltage-dividing resistor, a second voltage-dividing resistor, and an active controllable switch;

[0016] The first end of the energy extraction coil is connected to the first end of the third capacitor, the second end of the third capacitor is connected to the first AC input end of the first rectifier bridge, the second AC input end of the first rectifier bridge is connected to the negative pole of the energy extraction coil, the negative DC output end of the first rectifier bridge is grounded, the positive DC output end of the first rectifier bridge is connected to the first end of the filter capacitor, the second end of the filter capacitor is grounded, the first end of the filter capacitor is connected to the first end of the first voltage-dividing resistor, the first end of the first voltage-dividing resistor is the positive output end of the energy extraction module, the second end of the first voltage-dividing resistor is connected to the first end of the second voltage-dividing resistor, the second end of the second voltage-dividing resistor is grounded, the first end of the second voltage-dividing resistor is connected to the second input end of the maximum power point tracking submodule, the output end of the maximum power point tracking submodule is connected to the first end of the active controllable switch, the second end of the active controllable switch is the negative output end of the energy extraction module, and the third end of the active controllable switch is grounded.

[0017] Furthermore, the maximum power point tracking submodule includes: a voltage follower, a voltage comparator, a third voltage-dividing resistor, and a fourth voltage-dividing resistor;

[0018] The positive input end of the voltage follower is the second input end of the maximum power point tracking submodule, the negative input end of the voltage follower is connected to its own output end, the output end of the voltage follower is connected to the first end of the third voltage-dividing resistor, the second end of the third voltage-dividing resistor is connected to the first end of the fourth voltage-dividing resistor, the first end of the fourth voltage-dividing resistor is connected to the positive input end of the voltage comparator, the second end of the fourth voltage-dividing resistor is connected to the output end of the voltage comparator, the negative input end of the voltage comparator is the first input end of the maximum power point tracking submodule, the output end of the voltage comparator is the output end of the maximum power point tracking submodule, and the power supply port of the voltage follower and the power supply port of the voltage comparator are both power supply input ends of the maximum power point tracking submodule.

[0019] Furthermore, the reference voltage is:

[0020]

[0021] Among them, V REF is the reference voltage, V oc1 is the peak value of the sampling voltage of the sampling AC induced voltage generated by the sampling coil, V oc3 is the peak value of the AC induced voltage, ω is the angular frequency of the ambient magnetic field, L c3 is the energy-taking inductance of the energy-taking coil, N1 is the number of turns of the sampling coil, N3 is the number of turns of the energy-taking coil, R c3 is the energy taking coil resistance of the energy taking coil, R ed1 is the resistance value of the first resistor, R ed2 is the resistance value of the second resistor.

[0022] Furthermore, the maximum power point tracking submodule determines, based on the reference voltage, a target voltage value range required to output maximum power under the ambient magnetic field, including:

[0023] Determine the upper and lower thresholds of the target voltage range according to the following formula:

[0024]

[0025] V rect1 is the lower threshold of the target voltage value range, V rect2 is the upper threshold of the target voltage value range, R1 is the resistance value of the third voltage divider resistor, R2 is the resistance value of the fourth voltage divider resistor, V p It is the supply voltage value provided by the power supply module to the energy acquisition module.

[0026] Furthermore, a first ratio of the lower threshold value to the energy extraction voltage peak value, and a second ratio of the upper threshold value to the energy extraction voltage peak value, respectively satisfy:

[0027]

[0028] Among them, x and y are preset constants.

[0029] Furthermore, the maximum power point tracking submodule regulates the DC output voltage according to the target voltage value range, including:

[0030] When the reference voltage is greater than the divided voltage input to the positive input terminal of the voltage follower, it is determined that the DC output voltage reaches the lower threshold, the voltage comparator outputs a low level, the active controllable switch is turned off, and the filter capacitor is charged;

[0031] When the reference voltage is less than the divided voltage input to the positive input terminal of the voltage follower, it is determined that the DC output voltage reaches the upper limit threshold, the voltage comparator outputs a high level, the active controllable switch is turned on, and the filter capacitor is discharged.

[0032] The following beneficial effects are achieved by implementing the present invention:

[0033] The present invention provides a non-invasive magnetic energy harvesting device for maximum power point tracking, comprising: a magnetic core, a sampling module, a power supply module, and an energy harvesting module. The magnetic core has three layers of coils: the sampling coil is in the innermost layer, closely attached to the magnetic core; the power supply coil is sandwiched between the sampling coil and the energy harvesting coil; and the energy harvesting coil is in the outermost layer. The energy harvesting coil generates electrical energy for powering a load. The number of turns in the energy harvesting coil is greater than that of the sampling module and the power supply coil. Due to the large number of turns, the induced magnetic field generated by the energy harvesting coil is also much greater than the ambient magnetic field. Under the influence of the induced magnetic field, the sampling module generates a reference voltage that varies with the AC induced voltage generated by the energy harvesting coil. Furthermore, the maximum power point tracking submodule uses the reference voltage to determine the target voltage range required to output maximum power in the current magnetic field environment and regulates the DC output voltage based on the target voltage range, thereby achieving maximum power point tracking. Furthermore, the power supply module is used to provide electrical energy to the energy harvesting module. Specifically, the non-invasive magnetic energy harvesting device uses the power supply module internally and the energy harvesting module to supply power to an external load. This ensures that the power generated by the energy harvesting module is not consumed by its own circuit components, maintaining maximum output power. Therefore, the present invention replaces the single-chip microcomputer of the prior art with a sampling module and a maximum power point tracking submodule, and provides a power supply module to power its own circuit elements. Therefore, the non-invasive magnetic energy harvesting device disclosed in the present invention can be applied to many scenarios where it is impossible to add an external power supply, overcoming the low practicality of the non-invasive magnetic energy harvesting device with maximum power point tracking function in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 This is a schematic diagram of the circuit structure of an energy harvesting module of a non-invasive magnetic energy harvesting device provided in one embodiment of the present application;

[0036] Figure 2 This is a schematic structural diagram of a magnetic core and coil of a non-invasive magnetic energy harvesting device provided in one embodiment of the present application;

[0037] Figure 3 This is a schematic diagram of the circuit structure of a sampling module of a non-invasive magnetic energy collection device provided in one embodiment of the present application;

[0038] Figure 4 This is a schematic diagram of the circuit structure of a power supply module of a non-invasive magnetic energy harvesting device provided in one embodiment of the present application;

[0039] Figure 5 This is a schematic diagram of the winding structure of the energy extraction coil provided in one embodiment of the present application;

[0040] Figure 6 It is a schematic diagram of the circuit structure of an existing non-invasive magnetic energy harvesting device;

[0041] Figure 7 It is a non-invasive magnetic energy harvesting device V MPP * and P MPP * Curve graph showing changes in quality factor Q;

[0042] Figure 8 It is a curve diagram of the maximum output power and the maximum output voltage of the non-invasive magnetic energy harvesting device;

[0043] Figure 9 This is a schematic diagram of various voltage changes of a non-invasive magnetic energy harvesting device provided by an embodiment of the present application in a stable magnetic field environment;

[0044] Figure 10 This is a schematic diagram of various voltage changes in a non-invasive magnetic energy harvesting device under a fluctuating magnetic field environment provided by an embodiment of the present application;

[0045] Figure 11 This is a waveform diagram of the peak value of the sampling voltage of the energy harvesting coil provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0048] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0049] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0050] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0051] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0052] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0053] See also Figure 1 To overcome the low practicality of conventional non-invasive magnetic energy harvesting devices with maximum power point tracking (MPPT), an embodiment of the present invention provides a non-invasive magnetic energy harvesting device with maximum power point tracking (MPPT), comprising a magnetic core, a sampling module, a power supply module, and an energy extraction module. The sampling module comprises a sampling coil 21 wound around the magnetic core. The power supply module comprises a power supply coil 31 wound around the outer layer of the sampling coil 21. The energy extraction module comprises an energy extraction coil 41 wound around the outer layer of the power supply coil 31, a first rectifier bridge BD1, and a maximum power point tracking submodule 42. The number of turns of the energy extraction coil 41 is greater than that of the sampling coil 21 and the power supply coil 31.

[0054] The positive output terminal of the energy taking module is connected to the load R L The positive electrode of the energy taking module is connected to the negative output terminal of the load R L The negative electrode of the maximum power point tracking submodule 42 in the energy acquisition module is connected to the output end of the sampling module, and the power supply input end of the maximum power point tracking submodule 42 is connected to the output end of the power supply module;

[0055] The sampling module is used to use the sampling coil 21 to sense the induced magnetic field generated by the energy extraction coil 41 to generate a reference voltage;

[0056] The power supply module is used to use the power supply coil 31 to induce the induced magnetic field generated by the energy extraction coil 41 to provide electrical energy to the energy extraction module;

[0057] The energy acquisition module is used to use the energy acquisition coil 41 to sense the ambient magnetic field, generate an AC induced voltage, and use the first rectifier bridge BD1 to convert the AC induced voltage into a DC output voltage, and use the maximum power point tracking submodule 42 to determine the target voltage value range required to output maximum power under the ambient magnetic field according to the reference voltage, and regulate the DC output voltage according to the target voltage value range.

[0058] Preferably, the windings of the energy extraction coil 41 are in a regular hexagonal stacking structure.

[0059] In a preferred embodiment of the present invention, Figure 2 As shown in the figure, the main structure of the magnetic energy collector consists of an H-shaped magnetic core and three layers of windings, namely a sampling coil 21 with N1 turns, a power supply coil 31 with N2 turns, and an energy extraction coil 41 with N3 turns. Among them, the sampling coil 21 is in the innermost layer, close to the magnetic column part of the H-shaped magnetic core, the power supply coil 31 is sandwiched between the sampling coil 21 and the energy extraction coil 41, and the energy extraction coil 41 is in the outermost layer. The windings form a regular hexagonal stacking structure. Its structure is as follows Figure 5 The coils are insulated from each other and have no electrical connection. Figure 2 In the equation, R, w and r are the core radius, flux collector thickness and magnetic column radius respectively. coil and h are the length and height of the coil respectively. oc Indicates the magnetic induction intensity of the ambient magnetic field. w and δ are the radius of the enameled wire and the thickness of the insulation layer, respectively.

[0060] It should be noted that, for ease of understanding, the sampling coil 21, the power supply coil 31 and the energy extraction coil 41 are drawn as follows: Figure 1 、 3 , the equivalent AC power supply shown in 4, L c1 、R c1 、V oc1 are the sampling coil inductance, sampling coil resistance, and sampling voltage peak value of the sampling AC induced voltage of the sampling coil 21, L c2 、R c2 、V oc2 are the power supply coil inductance, power supply coil resistance, and power supply voltage peak value of the power supply AC induced voltage of the power supply coil 31, L c3 、R c3 、V oc3 are the energy extraction coil inductance, energy extraction coil resistance, and energy extraction voltage peak value of the AC induced voltage of the energy extraction coil 41 respectively.

[0061] According to the principle of electromagnetic induction, the non-invasive magnetic energy collector can gather the power frequency AC magnetic field in the environment and generate an induced voltage. Its open circuit voltage peak value V oc It is positively correlated with the number of coil turns N and the total magnetic induction intensity B, that is:

[0062] V oc =μ e ωNBA;

[0063] Among them, μ e is the effective magnetic permeability of the core, ω is the angular frequency of the magnetic field, and A is the cross-sectional area of ​​the core.

[0064] In this application, when the non-invasive magnetic energy collection device is working, the current flowing through each layer of coil will generate a new induced magnetic field in the coil, acting on the other two layers of coils, so the total magnetic field should be the superposition of the ambient magnetic field and the induced magnetic field; but since the number of turns of the energy collection coil 41 is much larger than that of the sampling coil 21 and the power supply coil 31, the induced magnetic field generated by the sampling coil 21 and the power supply coil 31 can be ignored, and only the influence of the induced magnetic field of the energy collection coil 41 on the other two coils needs to be considered. Figure 1 The equivalent circuit in the figure can be used to calculate the magnetic induction intensity B of the induced magnetic field generated by the energy extraction coil 41. s Magnetic induction intensity B of the ambient magnetic field oc The relationship satisfies:

[0065]

[0066] Among them, Q3 is the quality factor of the energy-taking coil 41. Since ωL is usually c3 Much larger than R c3 , that is, Q3 is much greater than 1, B s Much larger than B oc , so the total magnetic induction intensity in the sampling coil 21 and the power supply coil 31 is equal to B s Approximately equal.

[0067] In summary, if Figure 11 As shown, the peak open circuit voltage V generated by the sampling coil 21, the power supply coil 31 and the energy extraction coil 41 is oc1 、V oc2 and V oc3 The ratio can be expressed as:

[0068]

[0069] Preferably, the sampling module further includes: a diode D ed , the first capacitor C ed , the first resistor R ed1 and the second resistor R ed2 ;

[0070] The positive electrode of the sampling coil 21 and the diode D ed The positive terminal of the diode D is connected ed The negative electrode of the first capacitor C ed The first end of the first capacitor C ed The first end and the first resistor R ed1 The first end of the first capacitor C ed The second end of the first resistor R is connected to the negative electrode of the sampling coil 21. ed1 The second end and the second resistor R ed2The first end of the second resistor R ed2 The second end of the first capacitor C ed The second end of the second resistor R ed2 The second end of the second resistor R ed2 The first end serves as the output end of the sampling module.

[0071] Preferably, the reference voltage is:

[0072]

[0073] Among them, V REF is the reference voltage, V oc1 is the peak value of the sampling voltage of the sampling AC induced voltage generated by the sampling coil, V oc3 is the peak value of the AC induced voltage, ω is the angular frequency of the ambient magnetic field, L c3 is the energy-taking inductance of the energy-taking coil, N1 is the number of turns of the sampling coil, N3 is the number of turns of the energy-taking coil, R c3 is the energy taking coil resistance of the energy taking coil, R ed1 is the resistance value of the first resistor, R ed2 is the resistance value of the second resistor.

[0074] In a preferred embodiment of the present invention, Figure 3 As shown, the first capacitor C ed Through diode D ed Connected in series with the sampling coil 21, the first resistor R ed1 and the second resistor R ed2 Connected in series to the first capacitor C ed Both sides.

[0075] When the non-invasive magnetic energy collection device starts working, the sampling coil 21 will generate an induced voltage, which will pass through the diode D ed The first capacitor C at the rear end ed Charging, and due to the selection of the first resistor R ed1 and the second resistor R ed2 Much larger than the coil resistance R of the sampling coil 21 c1 , the charging rate is much greater than the discharging rate, so the voltage on the capacitor Ced in the equilibrium state is the peak value of the open circuit voltage of the sampling coil 21 V oc1 , and the reference voltage V REF for:

[0076]

[0077] Preferably, the power supply module further includes: a second capacitor C p2, the second rectifier bridge BD2, the linear regulator LDO, the first stabilizing capacitor C in And the second voltage stabilizing capacitor C out ;

[0078] The positive electrode of the power supply coil 31 and the second capacitor C p2 The first end of the second capacitor C p2 The second end of the second rectifier bridge BD2 is connected to the first AC input end of the second rectifier bridge BD2, the second AC input end of the second rectifier bridge BD2 is connected to the negative pole of the power supply coil 31, the negative DC output end of the second rectifier bridge BD2 is grounded, and the positive DC output end of the second rectifier bridge BD2 is connected to the first voltage stabilizing capacitor C in The first end of the first voltage stabilizing capacitor C in The first end is connected to the input end of the linear regulator LDO, and the output end of the linear regulator LDO is connected to the second stabilizing capacitor C out The first end of the first voltage stabilizing capacitor C in The second end of the second voltage stabilizing capacitor C out The second end of is grounded, and the output end of the linear regulator LDO is the output end of the power supply module.

[0079] In a preferred embodiment of the present invention, Figure 4 As shown, the second capacitor C p2 The first stabilizing capacitor C is connected in series between the power supply coil 31 and the input end of the second rectifier bridge BD2. The output end of the second rectifier bridge BD2 is connected to the input end of the linear regulator LDO. in And the second voltage stabilizing capacitor C out Connect to the input and output of the linear regulator LDO respectively.

[0080] When the non-invasive magnetic energy harvesting device starts working, the second capacitor C p2 The power supply coil 31 forms a series resonance with the coil inductance to reduce losses; the power supply coil 31 is rectified by the second rectifier bridge BD2 to form the first voltage stabilizing capacitor C at the input end. in When the first voltage stabilizing capacitor C in When the voltage across both ends reaches the rated operating voltage of the linear regulator LDO, the linear regulator switches to the second stabilizing capacitor C out Under the action of the output stable DC power supply voltage V P , which powers the follower Op amp and comparator Comp in the energy harvesting module, thus realizing self-power supply of the non-invasive magnetic energy harvesting device.

[0081] Preferably, the energy acquisition module further includes: a third capacitor C p3 , filter capacitor C rect , the first voltage divider resistor R d1, the second voltage divider resistor R d2 And the active controllable switch M N ;

[0082] The first end of the energy taking coil 41 is connected to the third capacitor C p3 The first end of the third capacitor C p3 The second end of the first rectifier bridge BD1 is connected to the first AC input end of the first rectifier bridge BD1, the second AC input end of the first rectifier bridge BD1 is connected to the negative electrode of the energy taking coil 41, the negative DC output end of the first rectifier bridge BD1 is grounded, and the positive DC output end of the first rectifier bridge BD1 is connected to the filter capacitor C rect The first end of the filter capacitor C rect The second end of the filter capacitor C rect The first end of the first voltage divider resistor R d1 The first end of the first voltage divider resistor R d1 The first end of the first voltage divider resistor R d1 The second end of the second voltage dividing resistor R d2 The first end of the second voltage divider resistor R d2 The second end of the second voltage divider resistor R d2 The first end of the maximum power point tracking submodule 42 is connected to the second input end of the maximum power point tracking submodule 42, and the output end of the maximum power point tracking submodule 42 is connected to the active controllable switch M N The first end of the active controllable switch M N The second end of the active controllable switch M is the negative output end of the energy taking module. N The third terminal is grounded.

[0083] Preferably, the maximum power point tracking submodule 42 includes: a voltage follower Op amp, a voltage comparator Comp, a third voltage-dividing resistor R1 and a fourth voltage-dividing resistor R2;

[0084] The positive input terminal of the voltage follower Op amp is the second input terminal of the maximum power point tracking sub-module 42, the negative input terminal of the voltage follower Op amp is connected to its own output terminal, the output terminal of the voltage follower Op amp is connected to the first terminal of the third voltage-dividing resistor R1, the second terminal of the third voltage-dividing resistor R1 is connected to the first terminal of the fourth voltage-dividing resistor R2, the first terminal of the fourth voltage-dividing resistor R2 is connected to the positive input terminal of the voltage comparator Comp, the second terminal of the fourth voltage-dividing resistor R2 is connected to the output terminal of the voltage comparator Comp, the negative input terminal of the voltage comparator Comp is the first input terminal of the maximum power point tracking sub-module 42, the output terminal of the voltage comparator Comp is the output terminal of the maximum power point tracking sub-module 42, and the power supply port of the voltage follower Op amp and the power supply port of the voltage comparator Comp are both the power supply input terminals of the maximum power point tracking sub-module 42.

[0085] In a preferred embodiment of the present invention, Figure 1 As shown, the third capacitor C p3 It is connected in series between the energy taking coil 41 and the input end of the first rectifier bridge BD1, and the output end of the first rectifier bridge BD1 is connected to the filter capacitor C rect The positive electrode of the filter capacitor C rect The negative terminal of the voltage follower Op amp is grounded, and the first voltage divider resistor R d1 and the second voltage divider resistor R d2 Then connect to the filter capacitor C rect Between the positive electrode and the ground, the load R L Connect to MOS tube M N Drain (second terminal) and filter capacitor C rect Between the positive poles, MOS tube M N The source (third terminal) is grounded; the positive input terminal of the voltage follower Op amp is connected to the first voltage divider resistor R d1 and the second voltage divider resistor R d2 The negative input of the voltage follower Op amp is connected to its own output; resistors R1 and R2 are connected in series between the output of the follower and the output of the voltage comparator Comp; the negative input of the comparator Comp is connected between Red1 and Red2 of module 1, the positive input of the comparator is connected between the third voltage divider resistor R1 and the fourth voltage divider resistor R2, and the output of the voltage comparator Comp is connected to the MOSFET M N The positive power supply terminals of the voltage comparator Comp and the voltage follower Op amp are both connected to the output terminal of the linear regulator LDO of the power supply module, and the negative power supply terminal is grounded.

[0086] Preferably, the maximum power point tracking submodule 42 determines, based on the reference voltage, a target voltage value range required to output the maximum power under the ambient magnetic field, including:

[0087] Determine the upper and lower thresholds of the target voltage range according to the following formula:

[0088]

[0089] Among them, V rect1 is the lower threshold of the target voltage value range, V rect2 is the upper threshold of the target voltage value range, R1 is the resistance value of the third voltage divider resistor, R2 is the resistance value of the fourth voltage divider resistor, V p It is the supply voltage value provided by the power supply module to the energy acquisition module.

[0090] Preferably, a first ratio of the lower threshold value to the energy extraction voltage peak value, and a second ratio of the upper threshold value to the energy extraction voltage peak value, respectively satisfy:

[0091]

[0092] Among them, x and y are preset constants.

[0093] In a preferred embodiment of the present invention, the existing circuit structure based on non-invasive magnetic energy collector is as follows: Figure 6 As shown in Figure (a), its equivalent circuit is as follows: Figure 6 As shown in Figure (b) of the figure. Under normal circumstances, after the external magnetic field is collected by the magnetic core of the non-invasive magnetic energy collector, an AC induced voltage is generated in the coil through electromagnetic induction. Compensation capacitor C p Used to offset the coil inductance L c The output end of the rectifier bridge is connected in parallel with the filter capacitor C rect To temporarily store the collected energy. The energy management circuit will C rect The energy stored in the magnetic energy harvester is converted into a stable DC power supply to power the sensor. When analyzing the output power, the energy management circuit and the sensor can be regarded as the equivalent load of the non-invasive magnetic energy harvester. In this case, the output power P out By the DC output voltage V rect Therefore, the maximum power point tracking circuit is used to control V rect To obtain maximum output power.

[0094] When the maximum power point is reached, the maximum output power P MPP and the maximum power point voltage V MPP With the quality factor Q and the coil open circuit voltage peak V oc Among them, the quality factor Q is determined by the coil inductance L c, coil resistance R c and the magnetic field angular frequency ω, which can be calculated as:

[0095] Q=ωL c / R c ;

[0096] To facilitate subsequent analysis, the voltage and power in the equivalent circuit are normalized, and the reference values ​​are V oc and V oc 2 / R c . Normalized output power P out *Calculated as:

[0097]

[0098] Among them, V rect * represents the normalized output voltage. α and β can be expressed as:

[0099]

[0100] Where n represents the harmonic order after Fourier decomposition of the rectifier bridge input voltage (square wave), and n=1 is the fundamental wave. out * and V rect The analysis of the relationship between * is based on the constant voltage load condition, and under this condition, the continuous conduction rectifier bridge input voltage waveform is an ideal square wave with a duty cycle of 50%. out *, it is necessary to perform Fourier decomposition on this square wave and sum the powers corresponding to the harmonics of different orders to obtain P out *.

[0101] By putting P out *The expression of V rect * Taking the derivative and finding the extreme point, we can get the normalized maximum power point voltage V MPP * and maximum power P MPP *The expression is:

[0102]

[0103] Figure 7 V MPP * and P MPP *The curve changes with the quality factor Q. When Q increases from 1, V MPP *Increased from 0.38 to around 0.39 and remained almost unchanged, P MPP * Maintained at about 0.125. Usually, Q is much greater than 1, so it can be considered that V MPP *=0.39, that is, the maximum power point voltage V MPP =0.39V oc.

[0104] In this regard, this application carried out experiments, and the experimental results are as follows Figure 8 As shown, at different V oc Under these conditions, the maximum output power always appears at 0.39V oc This verifies the reliability of the above conclusions.

[0105] In the non-invasive magnetic energy harvesting device of this embodiment, the upper and lower thresholds of the target voltage value range are:

[0106]

[0107] Among them, V rect1 is the lower threshold of the target voltage value range, V rect2 is the upper threshold of the target voltage value range, R1 is the resistance value of the third voltage divider resistor, R2 is the resistance value of the fourth voltage divider resistor, V p It is the supply voltage value provided by the power supply module to the energy acquisition module.

[0108] Furthermore, according to the above derivation process, when the first ratio of the lower threshold value to the energy extraction voltage peak value, and the second ratio of the upper threshold value to the energy extraction voltage peak value, respectively meet the following conditions, the non-intrusive magnetic energy harvesting device can achieve the maximum power point tracking function:

[0109]

[0110] Among them, x and y are preset constants.

[0111] According to the circuit structure of the non-invasive magnetic energy harvesting device of this embodiment, the first ratio and the second ratio are respectively:

[0112]

[0113] According to the above formula, V rect2 / V oc3 , that is, the second ratio is only related to the circuit component parameters, such as resistance, number of winding turns and quality factor, and is not related to V oc3 It has nothing to do with it. When the magnetic field fluctuates, the second ratio will not change. Although the lower limit of charge and discharge V rect1 With V oc3 The ratio will be because of V p With V oc3 However, since the power consumption of the voltage follower Op amp and the voltage comparator Comp chip is very low, V p Very small, so Usually much less than 0.39.

[0114] Therefore, it is only necessary to select the relevant circuit components in the non-invasive magnetic energy harvesting device according to the above relationship so that V rect2 / V oc3 Slightly greater than 0.39 (such as 0.395), V rect1 / V oc3 , which is also around 0.39, thus realizing the maximum power point tracking function.

[0115] Preferably, the maximum power point tracking submodule regulates the DC output voltage according to the target voltage value range, including:

[0116] When the reference voltage is greater than the divided voltage input to the positive input terminal of the voltage follower, it is determined that the DC output voltage reaches the lower threshold, the voltage comparator outputs a low level, the active controllable switch is turned off, and the filter capacitor is charged;

[0117] When the reference voltage is less than the divided voltage input to the positive input terminal of the voltage follower, it is determined that the DC output voltage reaches the upper limit threshold, the voltage comparator outputs a high level, the active controllable switch is turned on, and the filter capacitor is discharged.

[0118] In a preferred embodiment of the present invention, when the non-invasive magnetic energy harvesting device starts to work, the coil inductance L of the energy harvesting coil 41 is c3 and the third capacitor C p3 Forming series resonance, and after rectification through the first rectifier bridge BD1, it becomes the filter capacitor C rect Charging. DC output voltage V rect Through the first voltage divider resistor R d1 and the second voltage divider resistor R d2 After voltage division, the divided voltage V at the positive input of the voltage follower Opamp D and V rect satisfy:

[0119]

[0120] Among them, V D is the divided voltage, V rect is the DC output voltage, R d1 is the resistance value of the first voltage divider resistor, R d2 is the resistance value of the second voltage-dividing resistor.

[0121] After following the action, the output voltage of the voltage follower Op amp is also V D .

[0122] When the reference voltage V REF Greater than the divided voltage V at the positive input of the voltage comparator Comp DWhen the output voltage V EN is low level, MOS tube M N Turn off, load R L Disconnect, this is the charging process, until V D and V rect satisfy:

[0123]

[0124] At this time, the reference voltage V REF Less than the divided voltage V at the positive input of the voltage comparator Comp D Comparator Comp output voltage V EN is high level, MOS tube M N On, load R L Connect to the circuit, this is the discharge process, until V D and V rect satisfy:

[0125]

[0126] At this time, the voltage comparator outputs V EN It turns to low level again and enters the charging process again. In summary, the DC output voltage V rect The upper and lower charge and discharge thresholds are:

[0127]

[0128] Let V rect1 and V rect2 Represent the lower and upper thresholds of Vrect respectively, then the target voltage value range is [V rect1 ,V rect2 ].

[0129] The non-invasive magnetic energy harvesting device of the present application was tested when the ambient magnetic field was stable. The experimental results are as follows: Figure 9 As shown, the DC output voltage V rect The non-invasive magnetic energy harvesting device of the present invention is tested when the ambient magnetic field fluctuates. The experimental results are as follows: Figure 10 As shown, the non-invasive magnetic energy harvesting device can adapt to magnetic field fluctuations and always maintain the maximum output power in the real-time magnetic field environment, verifying the effectiveness of the maximum power point tracking function of the non-invasive magnetic energy harvesting device of the present application.

[0130] It should be noted that the device embodiments described above are merely illustrative, wherein the modules / units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed across multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement the present invention without inventive work.

[0131] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0132] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A non-invasive magnetic energy harvesting device for maximum power point tracking, characterized in that: include: A magnetic core, a sampling module, a power supply module, and an energy acquisition module; wherein the sampling module includes: a sampling coil wound around the magnetic core; the power supply module includes: a power supply coil wound around the outer layer of the sampling coil; the energy acquisition module includes: an energy acquisition coil wound around the outer layer of the power supply coil, a first rectifier bridge, and a maximum power point tracking submodule; wherein the number of turns of the energy acquisition coil is greater than that of the sampling coil and the power supply coil; The positive output terminal of the energy acquisition module is connected to the positive electrode of the load, the negative output terminal of the energy acquisition module is connected to the negative electrode of the load, the first input terminal of the maximum power point tracking submodule in the energy acquisition module is connected to the output terminal of the sampling module, and the power supply input terminal of the maximum power point tracking submodule is connected to the output terminal of the power supply module; The sampling module is configured to use the sampling coil to sense the induced magnetic field generated by the energy extraction coil to generate a reference voltage; The power supply module is used to use the power supply coil to induce the induced magnetic field generated by the energy extraction coil to provide electrical energy to the energy extraction module; The energy acquisition module is used to use the energy acquisition coil to sense the ambient magnetic field to generate an AC induced voltage, and use the first rectifier bridge to convert the AC induced voltage into a DC output voltage. The maximum power point tracking submodule is used to determine the target voltage value range required to output maximum power under the ambient magnetic field based on the reference voltage, and regulate the DC output voltage based on the target voltage value range.

2. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 1, characterized in that: The windings of the energy extraction coil are in a regular hexagonal stacking structure.

3. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 2, wherein: The sampling module further includes: a diode, a first capacitor, a first resistor, and a second resistor; The positive electrode of the sampling coil is connected to the positive electrode of the diode, the negative electrode of the diode is connected to the first end of the first capacitor, the first end of the first capacitor is connected to the first end of the first resistor, the second end of the first capacitor is connected to the negative electrode of the sampling coil, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the second end of the first capacitor, and the second end of the second resistor is grounded. The first end of the second resistor serves as the output end of the sampling module.

4. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 3, wherein: The power supply module further includes: a second capacitor, a second rectifier bridge, a linear regulator, a first voltage stabilizing capacitor, and a second voltage stabilizing capacitor; The positive pole of the power supply coil is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first AC input end of the second rectifier bridge, the second AC input end of the second rectifier bridge is connected to the negative pole of the power supply coil, the negative DC output end of the second rectifier bridge is grounded, the positive DC output end of the second rectifier bridge is connected to the first end of the first voltage-stabilizing capacitor, the first end of the first voltage-stabilizing capacitor is connected to the input end of the linear regulator, the output end of the linear regulator is connected to the first end of the second voltage-stabilizing capacitor, the second end of the first voltage-stabilizing capacitor is grounded, the second end of the second voltage-stabilizing capacitor is grounded, and the output end of the linear regulator is the output end of the power supply module.

5. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 4, characterized in that: The energy acquisition module further includes: a third capacitor, a filter capacitor, a first voltage-dividing resistor, a second voltage-dividing resistor, and an active controllable switch; The first end of the energy extraction coil is connected to the first end of the third capacitor, the second end of the third capacitor is connected to the first AC input end of the first rectifier bridge, the second AC input end of the first rectifier bridge is connected to the negative pole of the energy extraction coil, the negative DC output end of the first rectifier bridge is grounded, the positive DC output end of the first rectifier bridge is connected to the first end of the filter capacitor, the second end of the filter capacitor is grounded, the first end of the filter capacitor is connected to the first end of the first voltage-dividing resistor, the first end of the first voltage-dividing resistor is the positive output end of the energy extraction module, the second end of the first voltage-dividing resistor is connected to the first end of the second voltage-dividing resistor, the second end of the second voltage-dividing resistor is grounded, the first end of the second voltage-dividing resistor is connected to the second input end of the maximum power point tracking submodule, the output end of the maximum power point tracking submodule is connected to the first end of the active controllable switch, the second end of the active controllable switch is the negative output end of the energy extraction module, and the third end of the active controllable switch is grounded.

6. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 5, characterized in that: The maximum power point tracking submodule includes: a voltage follower, a voltage comparator, a third voltage-dividing resistor, and a fourth voltage-dividing resistor; The positive input end of the voltage follower is the second input end of the maximum power point tracking submodule, the negative input end of the voltage follower is connected to its own output end, the output end of the voltage follower is connected to the first end of the third voltage-dividing resistor, the second end of the third voltage-dividing resistor is connected to the first end of the fourth voltage-dividing resistor, the first end of the fourth voltage-dividing resistor is connected to the positive input end of the voltage comparator, the second end of the fourth voltage-dividing resistor is connected to the output end of the voltage comparator, the negative input end of the voltage comparator is the first input end of the maximum power point tracking submodule, the output end of the voltage comparator is the output end of the maximum power point tracking submodule, and the power supply port of the voltage follower and the power supply port of the voltage comparator are both power supply input ends of the maximum power point tracking submodule.

7. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 6, characterized in that: The reference voltage is: Among them, V REF is the reference voltage, V oc1 is the peak value of the sampling voltage of the sampling AC induced voltage generated by the sampling coil, V oc3 is the peak value of the AC induced voltage, ω is the angular frequency of the ambient magnetic field, L c3 is the energy-taking inductance of the energy-taking coil, N1 is the number of turns of the sampling coil, N3 is the number of turns of the energy-taking coil, R c3 is the energy taking coil resistance of the energy taking coil, R ed1 is the resistance value of the first resistor, R ed2 is the resistance value of the second resistor.

8. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 7, characterized in that: The maximum power point tracking submodule determines, based on the reference voltage, a target voltage value range required to output maximum power under the ambient magnetic field, including: Determine the upper and lower thresholds of the target voltage range according to the following formula: V rect1 is the lower threshold of the target voltage value range, V rect2 is the upper threshold of the target voltage value range, R1 is the resistance value of the third voltage divider resistor, R2 is the resistance value of the fourth voltage divider resistor, V p It is the supply voltage value provided by the power supply module to the energy acquisition module.

9. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 8, characterized in that: A first ratio of the lower threshold value to the energy extraction voltage peak value, and a second ratio of the upper threshold value to the energy extraction voltage peak value, respectively satisfy: Among them, x and y are preset constants.

10. The non-invasive magnetic energy harvesting device for maximum power point tracking according to claim 9, characterized in that: The maximum power point tracking submodule regulates the DC output voltage according to the target voltage value range, including: When the reference voltage is greater than the divided voltage input to the positive input terminal of the voltage follower, it is determined that the DC output voltage reaches the lower threshold, the voltage comparator outputs a low level, the active controllable switch is turned off, and the filter capacitor is charged; When the reference voltage is less than the divided voltage input to the positive input terminal of the voltage follower, it is determined that the DC output voltage reaches the upper limit threshold, the voltage comparator outputs a high level, the active controllable switch is turned on, and the filter capacitor is discharged.

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