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

Abstract

The invention relates to the technical field of new energy utilization, and discloses a non-intrusive type magnetic field energy collection maximum power tracking device and a control method, and the non-intrusive type magnetic field energy collection maximum power tracking device is constructed by adopting low-power-consumption devices without using external control equipment. When the environmental magnetic field intensity changes, electric energy conversion is carried out, then voltage change brought by voltage sampling tracking is detected, the sampling voltage of the corresponding maximum power point at the moment is found, the charging and discharging process of a load is controlled according to the sampling voltage, and the voltage of an energy storage capacitor is modulated. The maximum output power point of the non-intrusive magnetic energy collector is tracked, so that the output power of the device is improved; the technical problem that an existing control technology of a non-intrusive magnetic energy collector depends on external control equipment, and power consumption is high is solved.

Description

Technical Field

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

[0002] Since the magnetic core is not closed, the non-invasive (also known as independent) magnetic energy collector can be flexibly installed in locations with AC magnetic fields in the power grid, and has a wide range of application scenarios. In addition, non-invasive magnetic energy collectors have the advantages of being unaffected by weather, small size, and low cost. However, when the surrounding magnetic field strength changes, in order to continuously and reliably provide the required energy to the back-end load, the non-invasive magnetic energy collection device is usually required to obtain a larger output power according to the changes in the ambient magnetic field. Therefore, how to design a device that can adaptively increase the output power is very critical. In addition, since the device is usually used in scenarios such as power grids and rails, it is not easy to add an external power supply, so the self-power supply technology of the device is also an important part of the design.

[0003] At present, the control technology of existing non-invasive magnetic energy collectors mainly relies on single-chip microcomputers to realize circuit control. However, the power consumption of single-chip microcomputers is above MW level, and there is a problem of high power consumption. When the ambient magnetic field is weak, the output power of non-invasive magnetic energy collectors is low and cannot meet the power consumption requirements of single-chip microcomputers. Summary of the invention

[0004] The present invention provides a non-invasive magnetic field energy harvesting maximum power tracking device and a control method, which solves the technical problem that the control technology of the existing non-invasive magnetic energy harvester depends on external control equipment and has high power consumption.

[0005] A non-invasive magnetic field energy harvesting maximum power tracking device provided in a first aspect of the present invention comprises a magnetic energy collector, a rectifier and filter 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 AC magnetic field energy and convert it into AC output voltage;

[0007] The rectification and filtering module is used to convert the AC output voltage into a DC voltage to charge the energy storage capacitor through a sampling resistor, and determine the energy storage capacitor voltage and the sampling voltage;

[0008] The DC / DC conversion module is used to output a self-powered voltage for powering the voltage sampling and tracking module and the comparator output control module when the voltage of the energy storage capacitor reaches a preset chip operating voltage range;

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

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

[0011] Optionally, the magnetic energy collector comprises an AC power source, a magnetic energy inductor and a series resistor connected in series;

[0012] One end of the series resistor away from the magnetic energy inductor is connected to the rectification and filtering module through a compensation capacitor.

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

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

[0015] The output end 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 stabilizing capacitor;

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

[0020] A voltage stabilizing capacitor is connected in parallel to the power supply track end 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 end 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 track 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 end of the rectifier bridge and the sampling resistor, and is used to obtain a sampling voltage at a maximum power point;

[0027] The reverse input terminal of the voltage tracker is connected to a protection resistor;

[0028] The output end of the voltage tracker is connected to the protection resistor through a 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-dividing resistor is connected in series with the second voltage-dividing resistor;

[0032] One end of the first voltage-dividing resistor away from the second voltage-dividing resistor is connected to the output end of the voltage tracker through the diode;

[0033] One end of the second voltage-dividing resistor away from the first voltage-dividing resistor is connected to the output end of the voltage tracker through the diode.

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

[0035] The output end 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 second diode;

[0037] The other end of the second diode is connected to an end of the protection resistor away from the inverting input end 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 track terminal of the DC / DC chip;

[0040] The inverting input terminal of the hysteresis comparator is connected between the first voltage-dividing resistor and the second voltage-dividing 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] One end of the second current limiting resistor away from the third current limiting resistor is connected to the output end of the energy storage capacitor;

[0043] One end of the third current limiting resistor away from the second current limiting resistor is connected to the output end of the hysteresis comparator;

[0044] The output terminal 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 non-invasive magnetic field energy harvesting maximum power 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 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;

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

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

[0050] The power supply to the load and the energy storage capacitor is controlled based on the self-power supply voltage, the reference level and the energy storage capacitor voltage.

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

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

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

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

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

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

[0057] determining a low-level voltage threshold based on a self-supply voltage and a reference level;

[0058] Based on the reference level, determining a high level voltage threshold;

[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] It can be seen from the above technical solutions that the present invention has the following advantages:

[0062] In the present invention, the power frequency AC magnetic field energy 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 working voltage range, a self-powered voltage for powering a voltage sampling tracking module and a comparator output control module is output; based on the sampling voltage and the holding capacitor voltage, the voltage holding capacitor is charged and discharged and a reference level is output, and the reference level is output; based on the self-powered voltage, the reference level and the energy storage capacitor voltage, the load and the energy storage capacitor are powered on and controlled; the present invention does not need to use an external control device, and a non-invasive magnetic field energy collection maximum power tracking device is constructed by using low-power devices, and electric energy conversion is performed when the environmental magnetic field intensity changes, and then the voltage change caused by it is detected by voltage sampling tracking, and the sampling voltage corresponding to the maximum power point at this time is found, and the charging and discharging process of the load is controlled accordingly, and the energy storage capacitor voltage is modulated, so as to realize the tracking of the maximum output power point of the non-invasive magnetic energy collector, so as to improve the output power of the device; and the existing non-invasive magnetic energy collector control technology relies on external control devices and has a high power consumption. Technical problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0064] Figure 1 A control flow chart of a non-intrusive magnetic field energy harvesting maximum power tracking device according to an embodiment of the present invention;

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

[0066] Figure 3 It is a schematic diagram of the variation of the sampling voltage with the open circuit voltage according to an embodiment of the present invention;

[0067] Figure 4 A schematic diagram of changes in the energy storage capacitor voltage and the hysteresis comparator output voltage according to an embodiment of the present invention;

[0068] Figure 5 The present invention is a flowchart of a control method for a non-invasive magnetic field energy harvesting maximum power tracking device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0069] The embodiment of the present invention provides a non-invasive magnetic field energy harvesting maximum power tracking device and a control method, which are used to solve the technical problem that the control technology of the existing non-invasive magnetic energy harvester depends on external control equipment and has high power consumption.

[0070] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] The existing technology uses a linear extrapolation method to determine the open circuit voltage; however, when implementing the linear extrapolation method, the scheme needs to use the MSP430 microcontroller to adjust the duty cycle to obtain the value corresponding to the maximum power point, which consumes more power to drive the microcontroller, which is a more serious problem for non-invasive magnetic field energy collection with high output power requirements. In comparison, this scheme realizes the uninterrupted circuit to adaptively track the change of the open circuit voltage, and on this basis reduces the power loss caused by driving the microcontroller, which can further improve the output power; in addition, this scheme also uses the DC-DC power supply port to realize the self-power supply of the device, without the need to introduce an external power supply, which enhances the scope of application of the device.

[0072] See also Figure 1 and Figure 2 , a non-invasive magnetic field energy harvesting maximum power tracking device provided by the present invention includes a magnetic energy collector, a rectifier and filter module, a DC / DC conversion module, a voltage sampling and tracking module and a comparator output control module;

[0073] A magnetic energy collector is used to collect power frequency AC magnetic field energy and convert it into AC output voltage;

[0074] The rectifier and filter module is used to convert the AC output voltage into a DC voltage to charge the energy storage capacitor through a sampling resistor, and determine the energy storage capacitor voltage and the sampling voltage;

[0075] A DC / DC conversion module, which is used to output a self-powered voltage for powering the voltage sampling and tracking module and the comparator output control module when the voltage of the energy storage capacitor reaches a preset chip operating voltage range;

[0076] A voltage sampling and tracking module, used for charging and discharging the voltage holding capacitor and outputting a reference level based on the sampling voltage and the holding capacitor voltage;

[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-power supply voltage, the reference level and the energy storage capacitor voltage.

[0078] In the embodiment of the present invention, the power frequency AC magnetic field energy 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 working voltage range, a self-powered voltage for powering the voltage sampling tracking module and the comparator output control module is output; based on the sampling voltage and the holding capacitor voltage, the voltage holding capacitor is charged and discharged and a reference level is output, and the reference level is output; based on the self-powered voltage, the reference level and the energy storage capacitor voltage, the load and the energy storage capacitor are powered on and controlled; the present invention does not need to use an external control device, and a non-invasive magnetic field energy collection maximum power tracking device is constructed by using low-power devices, and electric energy conversion is performed when the environmental magnetic field intensity changes, and then the voltage change caused by it is detected by voltage sampling tracking, and the sampling voltage corresponding to the maximum power point at this time is found, and the charging and discharging process of the load is controlled accordingly, and the energy storage capacitor voltage is modulated, so as to realize the tracking of the maximum output power point of the non-invasive magnetic energy collector, so as to improve the output power of the device; the existing non-invasive magnetic energy collector control technology relies on external control devices and has a high power consumption. Technical problems.

[0079] See also Figure 1 and Figure 2 , the present invention provides a non-invasive magnetic field energy collection maximum power tracking device, the magnetic energy collector includes an AC power supply, a magnetic energy inductor and a series resistor connected in series;

[0080] One end of the series resistor away from the magnetic energy inductor is connected to the rectifier and filter module through a compensation capacitor.

[0081] It should be noted that the magnetic energy collector is a non-invasive magnetic field energy collector, referred to as a non-invasive magnetic energy collector, specifically an H-type magnetic energy collector. The equivalent circuit of the magnetic energy collector is constructed. The equivalent circuit consists of an AC power supply connected in series. , magnetic inductance and series resistance Composition, AC power supply One end is connected to the rectifier bridge, the AC power supply The other end of the magnetic inductor One end of the magnetic inductor is connected The other end of the series resistor One end of the series resistor The other end of the compensation capacitor Connect one end of the compensation capacitor The other end is connected to the rectifier bridge.

[0082] In the embodiment of the present invention, according to the principle of electromagnetic induction, the non-invasive magnetic field energy collector can collect the industrial frequency AC magnetic field in the environment and generate an induced voltage. Its structure can be equivalent to an AC voltage source. , Series resistance and magnetic inductance The non-invasive magnetic energy collector of the present invention is connected in series with a compensation capacitor to collect magnetic field energy through a magneto-electric conversion process to reduce losses. :When satisfied When the magnetic inductance With compensation capacitor Resonance occurs, reducing the impedance in the circuit, thereby increasing the induced voltage on the AC side, that is, the AC output voltage .

[0083] See also Figure 1 and Figure 2 , a non-invasive magnetic field energy collection maximum power tracking device provided by the present invention, the rectifier and filter module includes a rectifier bridge, a sampling resistor and an energy storage capacitor;

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

[0085] The output end 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 end of the rectifier bridge.

[0088] It should be noted that the output end of the magnetic energy collector is connected in series with a compensation capacitor. Then connected to the rectifier bridge, sampling resistor and energy storage capacitors After being connected in series, they are connected to the output side of the rectifier bridge.

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

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

[0091] For constant pressure load, the theoretical calculation results show that The value is about 0.395, and the charging power can reach the maximum, at which point the maximum power point of non-invasive magnetic energy harvesting is reached.

[0092] Assume that there is a voltage drop across the rectifier bridge diode, and its voltage drop value is: , then the sampling voltage at the maximum power point for:

[0093]

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

[0095] .

[0096] It should be noted that, since the diode has its own conduction voltage drop, a represents the ratio of the diode conduction voltage drop to the open-circuit voltage U of the AC power supply in the equivalent circuit.

[0097] See also Figure 3 , Figure 3 This is a schematic diagram showing the change of sampling voltage with open circuit voltage. Figure 3 Shows the sample voltage In the ambient magnetic field (open circuit voltage ) changes, the comparison diagram between the theoretical value and the measured value is used to verify the adaptive ability of the device.

[0098] See also Figure 1 and Figure 2 , a non-invasive magnetic field energy harvesting maximum power tracking device provided by the present invention, a DC / DC conversion module includes a DC / DC chip and a voltage stabilizing capacitor;

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

[0100] The power supply rail end of the DC / DC chip is connected in parallel with a voltage stabilizing capacitor;

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

[0102] The output end of the DC / DC chip is connected to a 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 stabilizing capacitor. The input voltage terminal of the DC / DC chip is directly connected to the energy storage capacitor. At both ends, a large voltage stabilizing capacitor is connected in parallel to the power rail end of the DC / DC chip , the enable terminal of the DC / DC chip and the hysteresis comparator of the comparator output control module Connection, the output of the DC / DC chip is directly connected to the load part.

[0104] In the embodiment of the present invention, when the energy storage capacitor voltage When the working voltage range of the DC / DC chip is reached, that is, the preset chip working voltage range, the power supply rail end is at the voltage stabilizing capacitor Under the action of the output of a stable DC power supply voltage, that is, the self-powered voltage , providing a stable self-powered power supply for the back-end operational amplifier.

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

[0106] Therefore, the DC / DC conversion module has the following functions:

[0107] (1) Provide power for the back-end operational amplifier;

[0108] (2) Controlled on / off process of the load power supply.

[0109] See also Figure 1 and Figure 2 , a non-invasive magnetic field energy harvesting maximum power tracking device provided by the present invention, a voltage sampling 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 end of the voltage tracker is connected to the power supply rail end 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 end of the rectifier bridge and the sampling resistor, so as to obtain the sampling voltage at the maximum power point;

[0113] The inverting input of the voltage tracker is connected with a protection resistor;

[0114] The output end of the voltage tracker is connected to the protection resistor through a 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 output the holding capacitor voltage;

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

[0118] One end of the first voltage-dividing resistor away from the second voltage-dividing resistor is connected to the output end of the voltage tracker through a diode;

[0119] One end of the second voltage-dividing resistor away from the first voltage-dividing resistor is connected to the output end of the voltage tracker through a diode.

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

[0121] The output end 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 second diode;

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

[0124] It should be noted that the voltage sampling and tracking module includes a voltage tracker , protection resistor , the first current limiting resistor , discharge resistor , the first voltage divider resistor , the second voltage divider resistor and voltage holding capacitor ,Voltage Tracker The power supply end is connected to the power supply rail end of the DC / DC chip, and the 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 Get the sampling voltage at the maximum power point , Voltage Tracker The reverse input terminal is connected to a protective resistor , the diode includes a first diode and a second diode, a voltage tracker The output end of the first diode 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 The inverting input terminal is connected to a voltage holding capacitor and discharge resistor Parallel, first voltage divider resistor With the second voltage divider resistor After the series connection, it is also connected to the voltage tracker through a diode The output terminal.

[0125] In the embodiment of the present invention, the voltage sampling and tracking module can adaptively track and detect the sampled voltage according to the change of the environmental magnetic field. Peak and through the first voltage divider resistor and the second voltage divider resistor The hysteresis comparator in the comparator output control module Provide reference level The specific working process is as follows:

[0126] Voltage Tracker The positive input terminal is connected to the first current limiting resistor Connect to the sampling voltage , determine the peak value of the sampling voltage according to the fractional voltage method , when the voltage holding capacitor The voltage on the holding capacitor Lower than the peak value of the sampling voltage When the voltage tracker Will hold the capacitor for voltage Charge until the voltage holds the capacitor The voltage on the holding capacitor With sampling voltage To achieve balance, .

[0127] When the ambient magnetic field strength weakens, the peak value of the sampled voltage Lower, voltage holding capacitor The holding capacitor voltage Higher than the peak value of the sampling voltage , at this time the voltage tracker Stop supplying voltage to the capacitor Charging, and due to the effect of the diode, there will be no reverse current, and the voltage will maintain the capacitor Start discharging through the resistor Discharge is performed and the voltage decreases until the voltage maintains the capacitor The holding capacitor voltage The peak value of the sampling voltage Reaching equilibrium again ( ) stops discharging.

[0128] Therefore, in equilibrium: .

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

[0130]

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

[0132]

[0133] See also Figure 1 and Figure 2 , a non-intrusive magnetic field energy harvesting maximum power tracking device provided by the present invention, 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 terminal of the hysteresis comparator is connected between the first voltage-dividing resistor and the second voltage-dividing resistor;

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

[0137] One end of the second current limiting resistor away from the third current limiting resistor is connected to the output end of the energy storage capacitor;

[0138] One end of the third current limiting resistor away from the second current limiting resistor is connected to the output end of the hysteresis comparator;

[0139] The output terminal 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 , the third current limiting resistor , Hysteresis Comparator and load , the second current limiting resistor With the third current limiting resistor Connected in series to the energy storage capacitor and hysteresis comparator Between the output terminals of the hysteresis comparator The power supply end is connected to the power supply rail end of the DC / DC chip, and the hysteresis comparator The positive input terminal is connected to the second current limiting resistor With the third current limiting resistor Between, the hysteresis comparator The inverting input terminal is connected to the first voltage divider resistor With the second voltage divider resistor Between, the hysteresis comparator The output end is connected to the enable end of the DC / DC chip, and the load Connect to the output voltage terminal of the DC / DC chip.

[0141] See also Figure 4 , Figure 4 Schematic diagram of the change of energy storage capacitor voltage and hysteresis comparator output voltage.

[0142] In the embodiment of the present 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 level (low potential), the enable terminal is low, the DC / DC chip is not a load Power supply, at this time the energy storage capacitor Enter the charging process.

[0144] When the storage capacitor voltage Rise to:

[0145]

[0146] Right now:

[0147]

[0148] This time the hysteresis comparator Output high level self-supply voltage , enable terminal High, the DC / DC chip starts to load Power supply, at this time the energy storage capacitor Enter the discharge process.

[0149] When the storage capacitor voltage Down to:

[0150]

[0151] Right now:

[0152]

[0153] This time the hysteresis comparator The output becomes low again (low potential), and the enable terminal When low, the DC / DC chip stops serving as a load Power supply, energy storage capacitor Enter the charging process again.

[0154] The advantages of the present invention are:

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

[0156] 2. The analog control circuit is self-powered and does not require external power supply. Technical means: Use the power supply port of the DC / DC chip to output the self-powered voltage to provide a stable DC power supply for the analog control circuit of the device to achieve stable power supply.

[0157] 3. Adaptive tracking of the maximum power point does not require interrupting the circuit to obtain the open circuit voltage. Technical means: Use the voltage change of the sampling resistor to reflect the change of the open circuit voltage. At the same time, establish the quantitative relationship of multiple parameters such as the open circuit voltage, energy storage capacitor voltage, sampling voltage, reference voltage, etc. according to the circuit logic relationship, and use the hysteresis comparator to realize the charging and discharging control of the energy storage capacitor at the maximum power point.

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

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

[0160] The control request refers to the request information for load power supply control issued when the magnetic energy collector senses a change in the ambient magnetic field strength.

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

[0162] Step 102: 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.

[0163] In the embodiment of the present invention, the AC output voltage is converted into a DC voltage through a rectifier bridge, and the energy storage capacitor is charged through 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 a preset chip operating voltage range, a self-powered voltage is output for powering the voltage sampling and tracking module and the comparator output control module.

[0165] In the embodiment of the present invention, when the voltage of the energy storage capacitor reaches a 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, charge and discharge the voltage holding capacitor and output a reference level.

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

[0168] S11. Determine the peak value of the sampling voltage based on the fractional voltage method.

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

[0170] For constant pressure load, the theoretical calculation results show that The value is about 0.395, and the charging power can reach the maximum, at which point the maximum power point of non-invasive magnetic energy harvesting is reached.

[0171] Assume that there is a voltage drop across the rectifier bridge diode, and its voltage drop value is: , then the sampling voltage at the maximum power point for:

[0172]

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

[0174]

[0175] Through the above process, the peak value of the sampling voltage can be determined .

[0176] S12, compare the sampling voltage with the holding capacitor voltage.

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

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

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

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

[0181] In the embodiment of the present 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, the reference level and the energy storage capacitor voltage, power supply control is performed on the load and the energy storage capacitor.

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

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

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

[0186]

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

[0188] It should be noted that the self-powered voltage and the peak value of the sampling voltage , combined with a second current limiting resistor , the third current limiting resistor , the first voltage divider resistor and the second voltage divider resistor , through the following formula:

[0189]

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

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

[0192] In the embodiment of the present invention, the reference level is used , combined with a second current limiting resistor With the third current limiting resistor , through the following formula:

[0193]

[0194] The high level voltage threshold can 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 the embodiment of the present invention, when the energy storage capacitor voltage Less than or equal to the low level voltage threshold When the hysteresis comparator The output becomes a low level (low potential), which cuts off the power to the load and charges the energy storage capacitor at the same time.

[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 the embodiment of the present invention, when the energy storage capacitor voltage Greater than or equal to the high level voltage threshold When the hysteresis comparator The output becomes high level to supply power to the load.

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

[0200] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0201] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A non-invasive magnetic field energy harvesting maximum power tracking device, characterized in that: It includes a magnetic energy collector, a rectifier and filter module, a DC / DC conversion module, a voltage sampling and tracking module, and a comparator output control module; The magnetic energy collector is used to collect power frequency AC magnetic field energy and convert it into AC output voltage; The rectification and filtering module is used to convert the AC output voltage into a DC voltage to charge the energy storage capacitor through a sampling resistor, and determine the energy storage capacitor voltage and the sampling voltage; The DC / DC conversion module is used to output a self-powered voltage for powering the voltage sampling and tracking module and the comparator output control module when the voltage of the energy storage capacitor reaches a preset chip operating voltage range; The voltage sampling and tracking module is used to charge and discharge the voltage holding capacitor based on the sampling voltage and the holding capacitor voltage and output a reference level; The comparator output control module is used to control the power supply of the load and the energy storage capacitor based on the self-power supply voltage, the reference level and the energy storage capacitor voltage.

2. The non-intrusive magnetic field energy harvesting maximum power tracking device according to claim 1, characterized in that: The magnetic energy collector comprises an AC power source, 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 and filtering module through a compensation capacitor.

3. The non-intrusive magnetic field energy harvesting maximum power tracking device according to claim 2, characterized in that: The rectification and filtering module includes a rectifier bridge, the sampling resistor and the energy storage capacitor; The input end of the rectifier bridge is connected to the compensation capacitor; The output end of the rectifier 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 rectifier bridge.

4. The non-intrusive magnetic field energy harvesting maximum power tracking device according to claim 3, characterized in that: The DC / DC conversion module includes a DC / DC chip and a voltage stabilizing capacitor; The DC / DC chip is connected in parallel with the energy storage capacitor; A voltage stabilizing capacitor is connected in parallel to the power supply track end of the DC / DC chip; The enable terminal of the DC / DC chip is connected to the comparator output control module; The output end of the DC / DC chip is connected to the load.

5. The non-intrusive magnetic field energy harvesting maximum power tracking device according to claim 4, characterized in that: 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; The power supply terminal of the voltage tracker is connected to the power supply track terminal of the DC / DC chip; The positive input terminal 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 rectifier bridge and the sampling resistor, and is used to obtain a sampling voltage at a maximum power point; The reverse input terminal of the voltage tracker is connected to a protection resistor; The output end of the voltage tracker is connected to the protection resistor through a diode; The voltage holding capacitor is connected to the diode; 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; The first voltage-dividing resistor is connected in series with the second voltage-dividing resistor; One end of the first voltage-dividing resistor away from the second voltage-dividing resistor is connected to the output end of the voltage tracker through the diode; One end of the second voltage-dividing resistor away from the first voltage-dividing resistor is connected to the output end of the voltage tracker through the diode.

6. The non-intrusive magnetic field energy harvesting maximum power tracking device according to claim 5, characterized in that: The diode comprises a first diode and a second diode; The output end of the voltage tracker 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; The other end of the second diode is connected to an end of the protection resistor away from the inverting input end of the voltage tracker.

7. The non-intrusive magnetic field energy harvesting maximum power tracking device according to claim 5, characterized in that: The comparator output control module includes a second current limiting resistor, a third current limiting resistor, a hysteresis comparator and the load; The power supply terminal of the hysteresis comparator is connected to the power supply track terminal of the DC / DC chip; The inverting input terminal of the hysteresis comparator is connected between the first voltage-dividing resistor and the second voltage-dividing resistor; The positive input terminal 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 to 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 to the output end of the hysteresis comparator; The output terminal of the hysteresis comparator is connected to the enable terminal of the DC / DC chip.

8. A control method for the non-intrusive magnetic field energy harvesting maximum power tracking device according to any one of claims 1 to 7, characterized in that: include: In response to control requests, it collects power frequency AC magnetic field energy and converts it into 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 voltage of the energy storage capacitor reaches the preset chip operating voltage range, a self-powered voltage is output for powering 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; The power supply to the load and the energy storage capacitor is controlled based on the self-power supply voltage, the reference level and the energy storage capacitor voltage.

9. The control method according to claim 8, characterized in that: The method of charging and discharging the voltage holding capacitor and outputting a reference level based on the sampling voltage and the holding capacitor voltage includes: Based on the fractional voltage method, the peak value of the sampling voltage is determined according to the sampling voltage; Compare the peak value of the sampled voltage with the holding capacitor voltage; If the holding capacitor voltage is less than the peak value of the sampling voltage, the voltage holding capacitor is charged; If the voltage of the holding capacitor is greater than or less than the peak value of the sampling voltage, the voltage holding capacitor is discharged.

10. The control method according to claim 8, characterized in that: The power supply control of the load and the energy storage capacitor based on the self-power supply voltage, the reference level and the energy storage capacitor voltage includes: determining a low-level voltage threshold based on a self-supply voltage and a reference level; Based on the reference level, determining a high level voltage threshold; 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; When the voltage of the energy storage capacitor is greater than or equal to the high level voltage threshold, the load is powered.

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