Non-invasive magnetic field energy collection maximum power tracking device and control method

Abstract

The application relates to the technical field of new energy utilization, and discloses a non-invasive magnetic field energy collection maximum power tracking device and a control method. The device is constructed by using low-power-consumption devices without using external control equipment, and can perform electric energy conversion when the environmental magnetic field strength changes, then detect the voltage change caused by voltage sampling tracking, find the sampling voltage of the corresponding maximum power point at the moment, and control the charging and discharging process of the load according to the sampling voltage, and modulate the energy storage capacitor voltage, so that the maximum output power point of the non-invasive magnetic energy collector is tracked, and the output power of the device is improved. The control technology of the existing non-invasive magnetic energy collector depends on external control equipment, and the technical problem of high power consumption exists.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy utilization, and particularly relates to a non-invasive magnetic field energy collection maximum power tracking device and a control method. BACKGROUND

[0002] Due to the non-closed magnetic core, the non-invasive (also known as independent) magnetic energy collector can be flexibly installed at a position with an alternating magnetic field in a power grid, and has a wide application scenario. In addition, the non-invasive magnetic energy collector also has advantages of being not affected by weather, small in size and low in cost. However, when the surrounding magnetic field strength changes, in order to continuously and reliably provide the required energy for the backend load, the non-invasive magnetic energy collection device usually needs to obtain a larger output power according to the change of the environmental magnetic field, and therefore how to design a device capable of adaptively improving the output power is very crucial. In addition, since the device is usually applied to scenarios such as power grids and tracks, it is not easy to add an external power supply, and therefore the self-power supply technology of the device is also an important part in the design.

[0003] At present, the control technology of the existing non-invasive magnetic energy collector mainly relies on a single-chip microcomputer to realize circuit control, and the power consumption of the single-chip microcomputer itself is above MW, which has the problem of high power consumption. When the environmental magnetic field is weak, the output power of the non-invasive magnetic energy collector is low, and cannot meet the power consumption demand of the single-chip microcomputer. SUMMARY

[0004] The present application provides a non-invasive magnetic field energy collection maximum power tracking device and a control method, which solves the technical problem of high power consumption of the existing non-invasive magnetic energy collector control technology which relies on external control equipment.

[0005] The first aspect of the present application provides a non-invasive magnetic field energy collection maximum power tracking device, which comprises a magnetic energy collector, a rectification and filtering module, a DC / DC conversion module, a voltage sampling and tracking module, and a comparator output control module.

[0006] The magnetic energy collector is used to collect power frequency alternating magnetic field energy and convert it into an alternating output voltage.

[0007] The rectification and filtering module is used to convert the alternating output voltage into a direct current voltage through a sampling resistor to charge an energy storage capacitor, and determine the energy storage capacitor voltage and the sampling voltage.

[0008] The DC / DC conversion module is used to output a self-power supply voltage for supplying power to the voltage sampling and tracking module and the comparator output control module when the energy storage capacitor voltage reaches a preset chip operating voltage interval.

[0009] The voltage sampling and tracking module is used to charge and discharge the voltage holding capacitor based on the sampled voltage and the holding capacitor voltage and output a reference level.

[0010] The comparator output control module is used to control the power supply to the load and the energy storage capacitor based on the self-powered voltage, the reference level, and the energy storage capacitor voltage.

[0011] Optionally, the magnetic energy harvester includes an AC power supply, a magnetic energy inductor, and a series resistor connected in series;

[0012] The end of the series resistor furthest from the magnetic inductor is connected to the rectifier and filter module via a compensation capacitor.

[0013] Optionally, the rectifier-filter module includes a rectifier bridge, the sampling resistor, and the energy storage capacitor;

[0014] The input terminal of the rectifier bridge is connected to the compensation capacitor;

[0015] The output terminal of the rectifier bridge is connected to one end of the sampling resistor;

[0016] The other end of the sampling resistor is connected to one end of the energy storage capacitor;

[0017] The other end of the energy storage capacitor is connected to the output end of the rectifier bridge.

[0018] Optionally, the DC / DC conversion module includes a DC / DC chip and a voltage regulator capacitor;

[0019] The DC / DC chip is connected in parallel with the energy storage capacitor;

[0020] A voltage-regulating capacitor is connected in parallel to the power supply rail of the DC / DC chip;

[0021] The enable terminal of the DC / DC chip is connected to the comparator output control module;

[0022] The output of the DC / DC chip is connected to the load.

[0023] Optionally, the voltage sampling and tracking module includes a voltage tracker, a protection resistor, a first current-limiting resistor, a discharge resistor, a first voltage-dividing resistor, a second voltage-dividing resistor, and the voltage holding capacitor;

[0024] The power supply terminal of the voltage tracker is connected to the power supply rail terminal of the DC / DC chip;

[0025] The positive input terminal of the voltage tracker is connected to one end of the first current-limiting resistor;

[0026] The other end of the first current-limiting resistor is connected between the output terminal of the rectifier bridge and the sampling resistor to obtain the sampling voltage at the maximum power point;

[0027] The protection resistor is connected to the inverting input terminal of the voltage tracker.

[0028] The output terminal of the voltage tracker is connected to one end of the discharge resistor via a first diode;

[0029] The voltage holding capacitor is connected to the diode;

[0030] The voltage holding capacitor is connected in parallel with the discharge resistor, and the voltage holding capacitor is used to output the holding capacitor voltage;

[0031] The first voltage divider resistor is connected in series with the second voltage divider resistor;

[0032] The end of the first voltage divider resistor furthest from the second voltage divider resistor is connected via a second diode to the end of the protection resistor furthest from the inverting input terminal of the voltage tracker.

[0033] The end of the second voltage divider resistor furthest from the first voltage divider resistor is grounded.

[0034] Optionally, the diode includes the first diode and the second diode;

[0035] The output terminal of the voltage tracker is connected to one end of the first diode;

[0036] The other end of the first diode is connected to one end of the discharge resistor;

[0037] The other end of the second diode is connected to the end of the protection resistor that is furthest from the inverting input of the voltage tracker.

[0038] Optionally, the comparator output control module includes a second current-limiting resistor, a third current-limiting resistor, a hysteresis comparator, and the load;

[0039] The power supply terminal of the hysteresis comparator is connected to the power supply rail terminal of the DC / DC chip;

[0040] The inverting input of the hysteresis comparator is connected between the first voltage divider resistor and the second voltage divider resistor;

[0041] The positive input terminal of the hysteresis comparator is connected between the second current-limiting resistor and the third current-limiting resistor;

[0042] The end of the second current-limiting resistor furthest from the third current-limiting resistor is connected to the output terminal of the energy storage capacitor;

[0043] The end of the third current-limiting resistor furthest from the second current-limiting resistor is connected to the output of the hysteresis comparator;

[0044] The output of the hysteresis comparator is connected to the enable terminal of the DC / DC chip.

[0045] A second aspect of the present invention provides a control method for the aforementioned non-invasive magnetic field energy harvesting maximum power point tracking device, comprising:

[0046] In response to control requests, it collects power frequency AC magnetic field energy and converts it into AC output voltage;

[0047] The AC output voltage is converted into DC voltage, which is then used to charge the energy storage capacitor through a sampling resistor, and the energy storage capacitor voltage and the sampling voltage are determined.

[0048] When the voltage of the energy storage capacitor reaches the preset chip operating voltage range, a self-powered voltage is output to power the voltage sampling and tracking module and the comparator output control module.

[0049] Based on the sampled voltage and the holding capacitor voltage, the voltage holding capacitor is charged and discharged, and a reference level is output.

[0050] Power supply control is performed on the load and energy storage capacitor based on the self-powered voltage, reference level, and energy storage capacitor voltage.

[0051] Optionally, the step of charging and discharging the voltage holding capacitor based on the sampled voltage and the holding capacitor voltage and outputting a reference level includes:

[0052] Based on the fractional voltage method, the peak value of the sampled voltage is determined according to the sampled voltage;

[0053] Compare the peak value of the sampled voltage with the voltage of the holding capacitor;

[0054] If the voltage holding capacitor is less than the peak value of the sampling voltage, then the voltage holding capacitor is charged.

[0055] If the voltage holding capacitor is greater than or less than the peak value of the sampling voltage, then the voltage holding capacitor is discharged.

[0056] Optionally, the power supply control of the load and energy storage capacitor based on the self-powered voltage, reference level, and energy storage capacitor voltage includes:

[0057] The low-level voltage threshold is determined based on the self-powered voltage and the reference level;

[0058] Determine the high-level voltage threshold based on the reference level;

[0059] When the voltage of the energy storage capacitor is less than or equal to the low-level voltage threshold, the load is powered off and the energy storage capacitor is charged.

[0060] When the voltage of the energy storage capacitor is greater than or equal to the high-level voltage threshold, the load is powered.

[0061] As can be seen from the above technical solutions, the present invention has the following advantages:

[0062] In this invention, the energy of the power frequency AC magnetic field is collected and converted into an AC output voltage. The DC voltage converted from the AC output voltage is used to charge the energy storage capacitor through a sampling resistor, and the energy storage capacitor voltage and the sampling voltage are determined. When the energy storage capacitor voltage reaches the preset chip operating voltage range, a self-powered voltage is output to power the voltage sampling and tracking module and the comparator output control module. Based on the sampling voltage and the holding capacitor voltage, the voltage holding capacitor is charged and discharged, and a reference level is output. Based on the self-powered voltage, the reference level, and the energy storage capacitor voltage, the power supply control of the load and the energy storage capacitor is performed. This invention does not require external control equipment. By using low-power devices to construct a non-invasive magnetic field energy harvesting maximum power point tracking device, it performs electrical energy conversion when the ambient magnetic field strength changes. Then, it detects the voltage change caused by the change through voltage sampling and tracking, finds the sampling voltage of the maximum power point at this time, and controls the charging and discharging process of the load accordingly, modulating the energy storage capacitor voltage. This achieves the tracking of the maximum output power point of the non-invasive magnetic energy harvester, thereby improving the output power of the device. This solves the technical problem that the control technology of existing non-invasive magnetic energy harvesters relies on external control equipment and has high power consumption. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is a control flowchart of the non-invasive magnetic field energy harvesting maximum power point tracking device according to an embodiment of the present invention;

[0065] Figure 2 This is an equivalent control circuit diagram of the non-invasive magnetic field energy harvesting maximum power point tracking device according to an embodiment of the present invention;

[0066] Figure 3 This is a schematic diagram showing the variation of the sampling voltage with the open-circuit voltage in an embodiment of the present invention;

[0067] Figure 4 This is a schematic diagram showing the changes in the energy storage capacitor voltage and the output voltage of the hysteresis comparator in an embodiment of the present invention.

[0068] Figure 5 This is a flowchart illustrating the steps of a control method for a non-invasive magnetic field energy harvesting maximum power point tracking device according to an embodiment of the present invention. Detailed Implementation

[0069] This invention provides a non-invasive magnetic field energy harvesting maximum power point tracking device and control method to solve the technical problem that existing non-invasive magnetic energy harvesters rely on external control equipment and have high power consumption.

[0070] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0071] Existing technologies use linear extrapolation to determine the open-circuit voltage. However, this method requires adjusting the duty cycle of an MSP430 microcontroller to obtain the maximum power point, consuming significant power to drive the microcontroller. This poses a serious problem for non-intrusive magnetic field energy harvesting, which demands high output power. In contrast, this solution implements uninterrupted circuitry to adaptively track changes in the open-circuit voltage, further reducing power loss due to microcontroller operation and improving output power. Furthermore, this solution utilizes a DC-DC power supply port for self-powering, eliminating the need for an external power source and broadening the device's applicability.

[0072] Please see Figure 1 and Figure 2 The present invention provides a non-invasive magnetic field energy harvesting maximum power point tracking device, comprising a magnetic energy harvester, a rectifier and filter module, a DC / DC converter module, a voltage sampling and tracking module, and a comparator output control module;

[0073] A magnetic energy harvester is used to collect the energy of an AC magnetic field at power frequency and convert it into an AC output voltage.

[0074] The rectifier and filter module is used to convert the AC output voltage into DC voltage, which charges the energy storage capacitor through the sampling resistor, and determines the energy storage capacitor voltage and the sampling voltage.

[0075] The DC / DC conversion module is used to output a self-powered voltage to power the voltage sampling and tracking module and the comparator output control module when the voltage of the energy storage capacitor reaches the preset chip operating voltage range.

[0076] The voltage sampling and tracking module is used to charge and discharge the voltage holding capacitor based on the sampled voltage and the holding capacitor voltage, and output a reference level.

[0077] The comparator output control module is used to control the power supply to the load and the energy storage capacitor based on the self-powered voltage, the reference level, and the energy storage capacitor voltage.

[0078] In this embodiment of the invention, power frequency AC magnetic field energy is collected and converted into AC output voltage; the DC voltage converted from AC output voltage is used to charge the energy storage capacitor through a sampling resistor, and the energy storage capacitor voltage and the sampling voltage are determined; when the energy storage capacitor voltage reaches the preset chip operating voltage range, a self-powered voltage is output to power the voltage sampling tracking module and the comparator output control module; based on the sampling voltage and the holding capacitor voltage, the voltage holding capacitor is charged and discharged, and a reference level is output; based on the self-powered voltage, the reference level, and the energy storage capacitor voltage, the power supply control of the load and the energy storage capacitor is performed; this invention does not require external control equipment. By using low-power devices to construct a non-invasive magnetic field energy harvesting maximum power point tracking device, it performs electrical energy conversion when the ambient magnetic field strength changes, and then detects the voltage change caused by the change through voltage sampling tracking to find the sampling voltage of the maximum power point at this time, and controls the charging and discharging process of the load accordingly, modulating the energy storage capacitor voltage, thereby realizing the tracking of the maximum output power point of the non-invasive magnetic energy harvester to improve the output power of the device; it solves the technical problem that the control technology of existing non-invasive magnetic energy harvesters relies on external control equipment and has high power consumption.

[0079] Please see Figure 1 and Figure 2 The present invention provides a non-invasive magnetic field energy harvesting maximum power tracking device, wherein the magnetic energy harvester includes an AC power supply, a magnetic energy inductor and a series resistor connected in series.

[0080] The end of the series resistor furthest from the magnetic inductor is connected to the rectifier and filter module via a compensation capacitor.

[0081] It should be noted that the magnetic energy harvester is a non-invasive magnetic field energy harvester, or simply a non-invasive magnetic energy harvester, specifically an H-type magnetic energy harvester. The equivalent circuit of the magnetic energy harvester is constructed using AC power supplies connected in series. Magnetic energy inductance and series resistor Composition, AC power supply One end is connected to the rectifier bridge, AC power supply. The other end is connected to the magnetic energy inductor One end is connected to the magnetic energy inductor. The other end is connected in series with a resistor One end is connected to a series resistor. The other end is connected to the compensation capacitor One end is connected to the compensation capacitor. The other end is connected to the rectifier bridge.

[0082] In this embodiment of the invention, based on the principle of electromagnetic induction, the non-invasive magnetic field energy harvester can collect the power frequency AC magnetic field in the environment and generate an induced voltage; its structure can be equivalent to an AC voltage source. Series resistors and magnetic energy inductance The non-invasive magnetic energy harvester of this invention is connected in series with a compensation capacitor to collect magnetic field energy through a magneto-electric conversion process; to reduce losses, the non-invasive magnetic energy harvester of this invention is connected in series with a compensation capacitor. When satisfied At that time, magnetic energy inductance With compensation capacitor Resonance occurs, reducing the impedance in the circuit, thus increasing the induced voltage on the AC side, i.e., the AC output voltage. .

[0083] Please see Figure 1 and Figure 2 The present invention provides a non-invasive magnetic field energy harvesting maximum power point tracking device, wherein the rectifier and filter module includes a rectifier bridge, a sampling resistor and an energy storage capacitor;

[0084] The input terminal of the rectifier bridge is connected to the compensation capacitor;

[0085] The output terminal of the rectifier bridge is connected to one end of the sampling resistor;

[0086] The other end of the sampling resistor is connected to one end of the energy storage capacitor;

[0087] The other end of the energy storage capacitor is connected to the output of the rectifier bridge.

[0088] It should be noted that a compensation capacitor is connected in series at the output of the magnetic energy harvester. Then connected to the rectifier bridge, sampling resistor and energy storage capacitors It is connected in series to the output side of the rectifier bridge.

[0089] In this embodiment of the invention, the rectifier bridge and the sampling resistor and energy storage capacitors This constitutes a rectifier and filter module, providing AC output voltage. The voltage is converted to DC by a rectifier bridge and then passes through a sampling resistor. Energy storage capacitor Charging, energy storage capacitor Used to temporarily store the output energy of the magnetic energy harvester.

[0090] It is worth mentioning that, according to the fractional voltage method, when the energy storage capacitor voltage... With open circuit voltage When a certain proportional relationship exists, that is Time (for energy storage capacitors) Its instantaneous charging process is similar to that of a constant voltage load, so it can be analyzed based on a constant voltage load.

[0091] For constant voltage loads, the results are obtained through theoretical calculations. The value is approximately 0.395, at which point the charging power can reach its maximum, which is the maximum power point for non-invasive magnetic energy harvesting.

[0092] Assume that the rectifier bridge diodes have a voltage drop, and that the voltage drop value is: The sampling voltage at the maximum power point for:

[0093]

[0094] Therefore, the peak value of the sampling voltage With open circuit voltage The relationship is as follows:

[0095] .

[0096] It should be noted that since diodes have their own forward voltage drop, 'a' represents the ratio of the diode's forward voltage drop to the open-circuit voltage U of the AC power supply in the equivalent circuit.

[0097] Please see Figure 3 , Figure 3 This is a schematic diagram showing the variation of the sampled voltage with the open-circuit voltage. Figure 3 The sampled voltage was displayed. In the ambient magnetic field (open circuit voltage) The diagram showing the comparison between theoretical and measured values ​​when the values ​​change is used to verify the adaptive capability of the device.

[0098] Please see Figure 1 and Figure 2 The present invention provides a non-invasive magnetic field energy harvesting maximum power point tracking device, wherein the DC / DC conversion module includes a DC / DC chip and a voltage regulator capacitor;

[0099] The DC / DC chip is connected in parallel with the energy storage capacitor;

[0100] A voltage-regulating capacitor is connected in parallel to the power supply rail of the DC / DC chip;

[0101] The enable terminal of the DC / DC chip is connected to the comparator output control module;

[0102] The output of the DC / DC chip is connected to the load.

[0103] It should be noted that the DC / DC conversion module refers to a DC-DC voltage conversion module, which consists of a DC / DC chip and a voltage regulating capacitor. The DC / DC chip's input voltage terminal is directly connected to the energy storage capacitor. At both ends, a large voltage regulator capacitor is connected in parallel to the power supply rail of the DC / DC chip. The enable terminal of the DC / DC chip and the hysteresis comparator of the comparator output control module The output of the DC / DC chip is directly connected to the load. part.

[0104] In this embodiment of the invention, when the energy storage capacitor voltage When the operating voltage range of the DC / DC chip is reached, that is, the preset operating voltage range of the chip, the power supply rail terminal is connected to the voltage regulator capacitor. Under its influence, it outputs a stable DC supply voltage, which is also known as a self-supply voltage. This provides a stable self-powered supply for the back-end operational amplifiers.

[0105] It should be noted that when the enable port voltage of the DC / DC chip... When the voltage at the enable port is low, the output port of the DC / DC chip is closed and does not supply power to the load. When the voltage is high, or high level, the output port of the DC / DC chip is enabled, and the output voltage is high. For load powered by.

[0106] Therefore, the functions of a DC / DC converter module are:

[0107] (1) Power supply to the back-end operational amplifier;

[0108] (2) Controlled start / stop of load power supply process.

[0109] Please see Figure 1 and Figure 2 The present invention provides a non-invasive magnetic field energy harvesting maximum power point tracking device, wherein the voltage sampling and tracking module includes a voltage tracker, a protection resistor, a first current limiting resistor, a discharge resistor, a first voltage dividing resistor, a second voltage dividing resistor, and a voltage holding capacitor;

[0110] The power supply terminal of the voltage tracker is connected to the power supply rail terminal of the DC / DC chip;

[0111] The positive input terminal of the voltage tracker is connected to one end of the first current-limiting resistor;

[0112] The other end of the first current-limiting resistor is connected between the output terminal of the rectifier bridge and the sampling resistor to obtain the sampling voltage at the maximum power point.

[0113] The inverting input of the voltage tracker is connected to a protective resistor;

[0114] The output of the voltage tracker is connected to one end of the discharge resistor via a first diode;

[0115] The voltage holding capacitor is connected to the diode;

[0116] The voltage holding capacitor is connected in parallel with the discharge resistor, and the voltage holding capacitor is used to maintain the output voltage of the holding capacitor.

[0117] The first voltage divider resistor is connected in series with the second voltage divider resistor;

[0118] The end of the first voltage divider resistor furthest from the second voltage divider resistor is connected via the second diode to the end of the protection resistor furthest from the inverting input of the voltage tracker.

[0119] The end of the second voltage divider resistor furthest from the first voltage divider resistor is grounded.

[0120] The diode includes a first diode and a second diode;

[0121] The output of the voltage tracker is connected to one end of the first diode;

[0122] The other end of the first diode is connected to one end of the discharge resistor;

[0123] The other end of the second diode is connected to the end of the protection resistor that is furthest from the inverting input of the voltage tracker.

[0124] It should be noted that the voltage sampling and tracking module includes a voltage tracker. , protective resistor First current-limiting resistor Discharge resistor First voltage divider resistor Second voltage divider resistor and voltage holding capacitor Voltage tracker The power supply terminal is connected to the power supply rail of the DC / DC chip, voltage tracker. The positive input terminal passes through the first current-limiting resistor. Connect to the output of the rectifier bridge and the sampling resistor Between these points, obtain the sampling voltage at the maximum power point. Voltage tracker The inverting input terminal is connected to a protective resistor. The diodes include a first diode and a second diode, and the voltage tracker... The output terminal is connected to one end of the first diode, the other end of the first diode is connected to one end of the second diode, and the other end of the second diode is connected to the protection resistor. Stay away from voltage trackers One end of the inverting input is connected to a voltage holding capacitor. and discharge resistor Parallel connection, first voltage divider resistor With the second voltage divider resistor After being connected in series, it is also connected to the voltage tracker via a diode. The output terminal.

[0125] In this embodiment of the invention, the voltage sampling and tracking module can adaptively track and detect the sampling voltage according to changes in the ambient magnetic field. peak And through the first voltage divider resistor Second voltage divider resistor Hysteresis comparator in the comparator output control module Provide reference level The specific work process is as follows:

[0126] Voltage tracker The positive input terminal is connected to the first current-limiting resistor. Connected to sampling voltage The peak value of the sampled voltage is determined using the fractional voltage method. When the voltage holds the capacitor The holding capacitor voltage Peak value below the sampling voltage At that time, voltage tracker It will be a voltage holding capacitor Charge until the voltage holding capacitor is held. The holding capacitor voltage With sampling voltage To achieve balance, that is .

[0127] When the ambient magnetic field strength decreases, the peak value of the sampling voltage... Reduce, voltage holding capacitor The holding capacitor voltage Peak value above the sampling voltage At this time, the voltage tracker Stop supplying voltage to the capacitor Charging, and due to the diode, no reverse current will occur; voltage holding capacitor. Start through the discharge resistor Discharge occurs, the voltage decreases, until the voltage holding capacitor... The holding capacitor voltage Peak value of the sampled voltage Reaching equilibrium again Discharge stops when ( ).

[0128] Therefore, the following conditions are met in equilibrium: .

[0129] First voltage divider resistor With the second voltage divider resistor Voltage holding capacitor The holding capacitor voltage Perform voltage division to obtain a reference level. :

[0130]

[0131] In summary, the reference level output by this module in balanced state satisfy:

[0132]

[0133] Please see Figure 1 and Figure 2 The present invention provides a non-invasive magnetic field energy harvesting maximum power point tracking device, wherein the comparator output control module includes a second current-limiting resistor, a third current-limiting resistor, a hysteresis comparator, and a load;

[0134] The power supply terminal of the hysteresis comparator is connected to the power supply rail terminal of the DC / DC chip;

[0135] The inverting input of the hysteresis comparator is connected between the first voltage divider resistor and the second voltage divider resistor;

[0136] The positive input of the hysteresis comparator is connected between the second current-limiting resistor and the third current-limiting resistor;

[0137] The end of the second current-limiting resistor furthest from the third current-limiting resistor is connected to the output terminal of the energy storage capacitor;

[0138] The end of the third current-limiting resistor furthest from the second current-limiting resistor is connected to the output of the hysteresis comparator.

[0139] The output of the hysteresis comparator is connected to the enable terminal of the DC / DC chip.

[0140] It should be noted that the comparator output control module includes a second current-limiting resistor. Third current-limiting resistor Hysteresis comparator and load Second current-limiting resistor With the third current-limiting resistor Connected in series to the energy storage capacitor Hysteresis comparator Between the output terminals of the hysteresis comparator The power supply terminal is connected to the power supply rail of the DC / DC chip, hysteresis comparator. The positive input terminal is connected to the second current-limiting resistor. With the third current-limiting resistor Between, hysteresis comparator The inverting input terminal is connected to the first voltage divider resistor. With the second voltage divider resistor Between, hysteresis comparator The output terminal is connected to the enable terminal of the DC / DC chip, and the load... Connect to the output voltage terminal of the DC / DC chip.

[0141] Please see Figure 4 , Figure 4 This is a schematic diagram showing the changes in the voltage of the energy storage capacitor and the output voltage of the hysteresis comparator.

[0142] In this embodiment of the invention, the comparator output control module is used to track the reference level obtained by adaptive voltage sampling. To control the load Power supply process.

[0143] The specific process is as follows: When the device starts working, the hysteresis comparator... The output is low (low potential), enabling pin. The DC / DC chip is not a load. Power supply, at this time energy storage capacitor Charging process begins.

[0144] When the energy storage capacitor voltage Rise to:

[0145]

[0146] Right now:

[0147]

[0148] At this time, the hysteresis comparator Output high-level self-powered voltage Enable terminal When the load is high, the DC / DC chip starts to load. Power supply, at this time energy storage capacitor The discharge process begins.

[0149] When the energy storage capacitor voltage Descending to:

[0150]

[0151] Right now:

[0152]

[0153] At this time, the hysteresis comparator The output goes low again (low potential), enabling the output. When the load is low, the DC / DC chip stops acting as a load. Power supply, energy storage capacitor The charging process has begun again.

[0154] Advantages of this invention:

[0155] 1. The circuit does not require microcontroller control and has low power consumption (μW level). Technical means: The non-invasive magnetic field energy harvesting maximum power point tracking device is circuit equivalent to obtain an analog control circuit. By using the analog control circuit for control, there is no need to use a microcontroller, and all analog control circuits use low-power devices.

[0156] 2. The analog control circuit is self-powered, requiring no external power supply. Technical means: The power supply port of the DC / DC chip outputs a self-powered voltage, providing a stable DC power supply to the device's analog control circuit, thus achieving stable power supply.

[0157] 3. Adaptive tracking of the maximum power point eliminates the need for circuit interruption to obtain the open-circuit voltage. Technical approach: The voltage change of the sampling resistor reflects the change in the open-circuit voltage. Simultaneously, based on circuit logic, quantitative relationships are established between various parameters such as open-circuit voltage, energy storage capacitor voltage, sampling voltage, and reference voltage. A hysteresis comparator is used to control the charging and discharging of the energy storage capacitor at the maximum power point.

[0158] Please see Figure 5 The present invention provides a control method for a non-invasive magnetic field energy harvesting maximum power point tracking device, comprising:

[0159] Step 101: Respond to the control request, collect the power frequency AC magnetic field energy and convert it into AC output voltage.

[0160] A control request refers to a request message issued by the magnetic energy harvester to control the power supply to the load when it senses a change in the intensity of the ambient magnetic field.

[0161] In this embodiment of the invention, when the intensity of the ambient magnetic field where the magnetic energy collector is located changes, the non-invasive magnetic field energy collector can collect the power frequency AC magnetic field in the environment and generate an induced voltage.

[0162] Step 102: Convert the AC output voltage into DC voltage and charge the energy storage capacitor through the sampling resistor, and determine the energy storage capacitor voltage and the sampling voltage.

[0163] In this embodiment of the invention, the AC output voltage is converted into DC voltage by a rectifier bridge, and then the energy storage capacitor is charged by a sampling resistor to determine the energy storage capacitor voltage and the sampling voltage at the maximum power point.

[0164] Step 103: When the voltage of the energy storage capacitor reaches the preset chip operating voltage range, output the self-powered voltage used to power the voltage sampling and tracking module and the comparator output control module.

[0165] In this embodiment of the invention, when the voltage of the energy storage capacitor reaches the preset operating voltage range of the DC / DC chip, a self-powered voltage is output.

[0166] Step 104: Based on the sampled voltage and the holding capacitor voltage, perform charging and discharging operations on the voltage holding capacitor and output a reference level.

[0167] Furthermore, step 104 may include the following sub-steps:

[0168] S11. Based on the fractional voltage method, determine the peak value of the sampled voltage according to the sampled voltage.

[0169] In this embodiment of the invention, according to the fractional voltage method, when the energy storage capacitor voltage... With open circuit voltage When a certain proportional relationship exists, that is Time (for energy storage capacitors) Its instantaneous charging process is similar to that of a constant voltage load, so it can be analyzed based on a constant voltage load.

[0170] For constant voltage loads, the results are obtained through theoretical calculations. The value is approximately 0.395, at which point the charging power can reach its maximum, which is the maximum power point for non-invasive magnetic energy harvesting.

[0171] Assume that the rectifier bridge diodes have a voltage drop, and that the voltage drop value is: The sampling voltage at the maximum power point for:

[0172]

[0173] Therefore, the peak value of the sampling voltage With open circuit voltage The relationship is as follows:

[0174]

[0175] The peak value of the sampling voltage can be determined through the above process. .

[0176] S12. Compare the sampled voltage with the holding capacitor voltage.

[0177] In this embodiment of the invention, the sampling voltage is compared with the holding capacitor voltage.

[0178] S13. If the holding capacitor voltage is less than the sampling voltage, then charge the voltage holding capacitor.

[0179] In this embodiment of the invention, if the holding capacitor voltage is less than the sampling voltage, the voltage holding capacitor is charged.

[0180] S14. If the voltage holding capacitor is greater than or less than the sampling voltage, then the voltage holding capacitor is discharged.

[0181] In this embodiment of the invention, if the voltage of the holding capacitor is greater than or less than the sampling voltage, the voltage holding capacitor is discharged.

[0182] Step 105: Based on the self-powered voltage, reference level, and energy storage capacitor voltage, control the power supply to the load and energy storage capacitor.

[0183] Furthermore, step 105 may include the following sub-steps:

[0184] S21. Determine the low-level voltage threshold based on the self-powered voltage and the reference level.

[0185] In this embodiment of the invention, a self-powered voltage is used. and reference level Combined with the second current-limiting resistor With the third current-limiting resistor The following formula is used:

[0186]

[0187] The low-level voltage threshold can then be calculated. .

[0188] It should be noted that a self-powered voltage is used. and the peak value of the sampling voltage Combined with the second current-limiting resistor Third current-limiting resistor First voltage divider resistor Second voltage divider resistor The following formula is used:

[0189]

[0190] The low-level voltage threshold can also be calculated. .

[0191] S22. Determine the high-level voltage threshold based on the reference level.

[0192] In this embodiment of the invention, a reference level is used. Combined with the second current-limiting resistor With the third current-limiting resistor The following formula is used:

[0193]

[0194] The high-level voltage threshold can then be calculated. .

[0195] S23. When the voltage of the energy storage capacitor is less than or equal to the low-level voltage threshold, the load is powered off and the energy storage capacitor is charged.

[0196] In this embodiment of the invention, when the energy storage capacitor voltage Less than or equal to the low-level voltage threshold At that time, hysteresis comparator The output goes low (low potential), powering off the load and simultaneously charging the energy storage capacitor.

[0197] S24. When the voltage of the energy storage capacitor is greater than or equal to the high-level voltage threshold, the load is powered.

[0198] In this embodiment of the invention, when the energy storage capacitor voltage Greater than or equal to the high-level voltage threshold At that time, hysteresis comparator The output goes high to supply power to the load.

[0199] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0200] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0201] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A non-intrusive magnetic field energy harvesting maximum power tracking device, characterized by, The magnetic energy collector, the rectification filter module, the DC / DC conversion module, the voltage sampling tracking module and the comparator output control module are connected in series. The magnetic energy collector is used for collecting the power frequency alternating current magnetic field energy and converting it into an alternating output voltage. The rectification filter module is used for converting the alternating output voltage into a direct current voltage to charge an energy storage capacitor through a sampling resistor and determining the energy storage capacitor voltage and the sampling voltage. The DC / DC conversion module is used for outputting a self-powered voltage for powering the voltage sampling tracking module and the comparator output control module when the energy storage capacitor voltage reaches a preset chip working voltage interval. The voltage sampling tracking module is used for charging and discharging a voltage holding capacitor based on the sampling voltage and the holding capacitor voltage and outputting a reference level. The comparator output control module is used for powering control of a load and the energy storage capacitor based on the self-powered voltage, the reference level and the energy storage capacitor voltage. The magnetic energy collector comprises an alternating current power supply, a magnetic energy inductor and a series resistor connected in series. One end of the series resistor away from the magnetic energy inductor is connected to the rectification filter module through a compensation capacitor. The DC / DC conversion module comprises a DC / DC chip and a voltage stabilizing capacitor. The DC / DC chip is connected in parallel with the energy storage capacitor. The voltage stabilizing capacitor is connected in parallel with a power supply track end of the DC / DC chip. An enable end of the DC / DC chip is connected to the comparator output control module. An output end of the DC / DC chip is connected to the load.

2. The non-invasive magnetic field energy harvesting maximum power tracking device of claim 1, wherein, The rectification filter module comprises a rectification bridge, the sampling resistor and the energy storage capacitor. An input end of the rectification bridge is connected to the compensation capacitor. An output end of the rectification bridge is connected to one end of the sampling resistor. The other end of the sampling resistor is connected to one end of the energy storage capacitor. The other end of the energy storage capacitor is connected to the output end of the rectification bridge.

3. The non-invasive magnetic field energy harvesting maximum power tracking device of claim 2, wherein, The voltage sampling tracking module comprises a voltage tracker, a protection resistor, a first current limiting resistor, a discharging resistor, a first voltage dividing resistor, a second voltage dividing resistor and the voltage holding capacitor. A power supply end of the voltage tracker is connected to the power supply track end of the DC / DC chip. A positive input end of the voltage tracker is connected to one end of the first current limiting resistor. The other end of the first current limiting resistor is connected between the output end of the rectification bridge and the sampling resistor, used for obtaining the sampling voltage at the maximum power point. The protection resistor is connected to a reverse input end of the voltage tracker. The output end of the voltage tracker is connected to one end of the discharging resistor through a first diode. The voltage holding capacitor is connected to a diode. The voltage holding capacitor is connected in parallel with the discharging resistor, and the voltage holding capacitor is used for outputting the holding capacitor voltage. The first voltage dividing resistor and the second voltage dividing resistor are connected in series. One end of the first voltage dividing resistor away from the second voltage dividing resistor is connected to one end of the protection resistor away from the reverse input end of the voltage tracker through a second diode. One end of the second voltage dividing resistor away from the first voltage dividing resistor is grounded.

4. The non-invasive magnetic field energy harvesting maximum power tracking device of claim 3, wherein, The diode comprises the first diode and the second diode; The output end of the voltage tracker is connected with one end of the first diode; The other end of the first diode is connected with one end of the discharge resistor; The other end of the second diode is connected with one end of the protection resistor away from the reverse input end of the voltage tracker.

5. The non-invasive magnetic field energy harvesting maximum power tracking device of claim 3, wherein, The comparator output control module comprises a second current-limiting resistor, a third current-limiting resistor, a hysteresis comparator and the load; The power supply end of the hysteresis comparator is connected with the power supply track end of the DC / DC chip; The reverse input end of the hysteresis comparator is connected between the first voltage dividing resistor and the second voltage dividing resistor; The forward input end of the hysteresis comparator is connected between the second current-limiting resistor and the third current-limiting resistor; One end of the second current-limiting resistor away from the third current-limiting resistor is connected with the output end of the energy storage capacitor; One end of the third current-limiting resistor away from the second current-limiting resistor is connected with the output end of the hysteresis comparator; The output end of the hysteresis comparator is connected with the enable end of the DC / DC chip.

6. A control method applied to the non-invasive magnetic field energy harvesting maximum power tracking device according to any one of claims 1-5, characterized in that, Comprise: In response to a control request, collect power frequency alternating magnetic field energy and convert it into alternating output voltage; The direct current voltage converted from the alternating output voltage charges the energy storage capacitor through the sampling resistor, and determines the energy storage capacitor voltage and the sampling voltage; When the energy storage capacitor voltage reaches a preset chip operating voltage interval, output a self-powered voltage for powering the voltage sampling tracking module and the comparator output control module; Based on the sampling voltage and the hold capacitor voltage, charge and discharge the voltage hold capacitor and output a reference level; Based on the self-powered voltage, the reference level and the energy storage capacitor voltage, control the power supply of the load and the energy storage capacitor.

7. The control method according to claim 6, characterized by, The method comprises: Based on the fractional voltage method, determine the peak value of the sampling voltage according to the sampling voltage; Compare the peak value of the sampling voltage with the hold capacitor voltage; If the hold capacitor voltage is less than the peak value of the sampling voltage, charge the voltage hold capacitor; If the hold capacitor voltage is greater than or less than the peak value of the sampling voltage, discharge the voltage hold capacitor.

8. The control method according to claim 6, characterized by, The method comprises: Based on the self-powered voltage and the reference level, determine a low-level voltage threshold; Based on the reference level, determine a high-level voltage threshold; When the energy storage capacitor voltage is less than or equal to the low-level voltage threshold, perform power-off operation on the load and charging operation on the energy storage capacitor; When the energy storage capacitor voltage is greater than or equal to the high-level voltage threshold, perform power supply operation on the load.

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