Power management system

Abstract

The invention relates to the technical field of power management, and discloses a power management system. The electromagnetic field energy taking device is used for collecting a time-varying electromagnetic field generated by power equipment and converting the time-varying electromagnetic field into alternating-current electric energy; the rectifying circuit is used for converting the alternating-current electric energy into direct-current electric energy in an active or passive rectifying mode; the power supply module is used for automatically switching a plurality of power supply modes according to the magnitude of the direct-current electric energy; the energy storage circuit is used for storing direct-current electric energy and enabling a microprocessor and a load circuit through a DC-DC voltage stabilizing circuit so as to realize self-starting of a system, and the energy storage circuit is used for controlling an energy taking interval and controlling on and off of a rectifying circuit so as to realize self-starting of the system. According to the invention, the microprocessor is used for realizing the maximum energy taking power of the system in each energy taking interval, and the system can be automatically started, has high energy taking power, can stably and continuously supply power to the load, and has relatively high reliability and stability.

Description

Technical Field

[0001] The present invention relates to the technical field of power management, and in particular to a power management system. Background Art

[0002] With the development of wireless sensor network technology, sensors are widely used in power systems to monitor the operating status of power equipment and ensure the steady-state operation of the power system.

[0003] There is a time-varying electromagnetic field around the power equipment. The electromagnetic field energy can only be collected through an electromagnetic field energy harvesting device and an efficient power management system to power the sensor. However, the power management system has problems such as short battery life and troublesome replacement, low rectification efficiency of the rectifier circuit and high loss of passive rectification devices, and different energy harvesting environments, which causes the corresponding energy harvesting current to change, making it impossible to provide stable and continuous power supply to the load.

[0004] It can be seen that how to design a power management system that can self-start, has high energy extraction power and can provide stable and continuous power supply to the load has become a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0005] The present invention provides a power management system to solve the problem of how to design a power management system that can start itself, has high energy extraction power and can provide stable and continuous power supply to a load.

[0006] In order to solve the above technical problems, the present invention provides a power management system, including: an electromagnetic field energy harvesting device, a rectifier circuit, a supercapacitor voltage hysteresis control circuit, an energy storage circuit, a microprocessor, a DC-DC voltage stabilizing circuit and a load circuit; wherein, The electromagnetic field energy harvesting device is used to collect the time-varying electromagnetic field generated by the power equipment and convert it into AC power; The rectifier circuit is used to convert the AC power transmitted by the electromagnetic field energy harvesting device into DC power by active rectification or passive rectification; The supercapacitor voltage hysteresis control circuit is used to automatically switch between multiple power supply modes according to the size of the DC power transmitted by the rectifier circuit, so as to charge and discharge the energy storage circuit; The energy storage circuit is used to store the DC power transmitted by the rectifier circuit, and enable the microprocessor and the load circuit through the DC-DC voltage regulator circuit to achieve self-starting of the system; The microprocessor is used to control the energy extraction interval and control the on and off of the rectifier circuit so that the system can maximize the energy extraction power in each energy extraction interval.

[0007] As one of the preferred schemes, the electromagnetic field energy harvesting device includes an energy harvesting coil and a magnetic core; wherein, the primary side of the energy harvesting coil is connected to the power equipment, and the secondary side of the energy harvesting coil is connected to the rectifier circuit; the magnetic core includes a closed magnetic core composed of two magnetic core blocks.

[0008] As one of the preferred solutions, the rectifier circuit is a synchronous full-bridge rectifier circuit, which includes two PMOS tubes Q1 and Q2, two NMOS tubes Q3 and Q4, and four Schottky diodes D1, D2, D3, and D4; wherein the source of Q1 is connected to the source of Q2, the drain of Q1 and the drain of Q2 are respectively connected to the drain of Q3 and the drain of Q4, the four MOS tubes are connected in sequence to form a full-bridge rectifier circuit, and the four Schottky diodes are respectively connected in parallel with the four MOS tubes; The rectifier circuit is also used for: When the AC power is in a positive half cycle, Q1 and Q4 are controlled to be turned on to actively rectify the AC power to obtain DC power; when the AC power is in a negative half cycle, Q2 and Q3 are controlled to be turned on to actively rectify the AC power to obtain DC power; When the AC power is in the positive half cycle, D1 and D4 are controlled to perform passive rectification on the AC power to obtain DC power; when the AC power is in the negative half cycle, D2 and D3 are controlled to perform passive rectification on the AC power to obtain DC power.

[0009] As one of the preferred solutions, the energy storage circuit includes a supercapacitor and a voltage monitor; wherein the positive electrode of the supercapacitor is connected to the input end of the voltage monitor, and the output end of the voltage monitor is respectively connected to the enable ends of the microprocessor and the load circuit.

[0010] As one preferred solution, the energy storage circuit is also used for: receiving the DC power transmitted by the rectifier circuit and charging the supercapacitor so that the supercapacitor stores energy; When it is detected that the voltage of the supercapacitor is greater than the built-in voltage of the voltage monitor, the voltage monitor is controlled to output a high level, and the microprocessor and the load circuit are connected to the system by enabling the DC-DC voltage regulator circuit, so that the system completes self-starting; When it is detected that the voltage of the supercapacitor is charged to the upper limit voltage, the rectifier circuit is short-circuited, and the load circuit is powered solely by the supercapacitor until the voltage of the supercapacitor drops to the charging threshold, and the DC power transmitted by the rectifier circuit is received again to charge the supercapacitor.

[0011] As one of the preferred schemes, the supercapacitor voltage hysteresis control circuit includes an NMOS tube Q5, a hysteresis comparator and a Schottky diode D5; wherein, the positive input terminal of the hysteresis comparator is connected to the positive electrode of the supercapacitor, the inverting input terminal of the hysteresis comparator is connected to the reference voltage, the output terminal of the hysteresis comparator is connected to the gate of Q5, the drain of Q5 is connected to the negative electrode of the supercapacitor, and the source of Q5 is connected to the anode of D5.

[0012] As one preferred solution, the supercapacitor voltage hysteresis control circuit is further used for: Setting the upper threshold voltage and the lower threshold voltage of the hysteresis comparator; When it is detected that the voltage of the supercapacitor rises to the upper threshold voltage, the hysteresis comparator is controlled to output a high level and the Q5 tube is turned on, so that the DC power is short-circuited to the ground, so that the supercapacitor alone supplies power to the load circuit; When it is detected that the voltage of the super capacitor drops to the lower threshold voltage, the hysteresis comparator is controlled to output a low level and the Q5 tube is turned off, so that the DC power can recharge the super capacitor.

[0013] As one preferred solution, the microprocessor is further used for: Receiving the DC power transmitted by the rectifier circuit to determine the peak position of the DC power, and determining the start and end time of the energy extraction interval based on the DC power to control the opening and closing of the rectifier circuit; the energy extraction interval is configured to be symmetrical about the peak position; Performing real-time monitoring on the load circuit, and when the load circuit changes, obtaining the actual energy extraction interval of the next cycle to compare with the preset length; If the two are the same, the current rectifier circuit turn-on time is maintained at the optimal value, and energy is continued to be drawn in the next half cycle; if the two are not equal, the actual energy drawing interval is assigned to the system to update the current rectifier circuit turn-on time through the system, and in each half cycle, the rectifier circuit turn-on time is cyclically updated according to the real-time changes of the load circuit to draw energy, so that the system can maximize the energy drawing power in each energy drawing interval.

[0014] As one preferred solution, the supercapacitor voltage hysteresis control circuit is further used for: receiving the DC power transmitted by the rectifier circuit, and comparing the DC power with a critical current; the critical current is a primary-side current that the DC power needs to meet to maintain a charging current of the load circuit; When it is detected that the DC power is greater than the critical current and the voltage of the supercapacitor is not less than the built-in voltage and less than the upper limit voltage, the hysteresis comparator is controlled to output a low level and the Q5 tube is turned off, so that the microprocessor starts to control energy acquisition and the system switches to a mode in which the load circuit is powered solely by the DC power; When it is detected that the DC power is greater than the critical current and the voltage of the supercapacitor is greater than the upper limit voltage, the hysteresis comparator is controlled to output a high level and enable the Q5 tube to be turned on, so that the microprocessor controls the rectifier circuit to turn off active rectification and switches the system to a mode in which the supercapacitor is used to supply power to the load circuit alone; When it is detected that the DC power is less than the critical current, the hysteresis comparator is controlled to output a low level and the Q5 tube is enabled to be turned off, so that the microprocessor controls the rectifier circuit to start active rectification and switches the system to a mode in which the load circuit is supplied with a mixed power by the DC power and the supercapacitor.

[0015] As one of the preferred solutions, the load circuit includes a charging chip and a load, and the load is a thin film battery; the DC-DC voltage regulator circuit is used to provide a constant power supply to the charging chip and the microprocessor respectively.

[0016] Compared with the prior art, the embodiments of the present invention have the following advantages: (1) The present invention adopts a separable closed magnetic core, which makes the electromagnetic field energy harvesting device easier to install, and the magnetic field coupling efficiency of the closed magnetic core is improved compared with the non-closed magnetic core, which can achieve an increase in energy harvesting power; (2) In response to the current fluctuations generated by power equipment, the present invention designs multiple working modes, controls the charging and discharging process of the energy storage circuit through the supercapacitor voltage hysteresis control circuit, and realizes automatic switching of multiple working modes based on the size of DC power, so as to provide continuous and stable power supply to the load; (3) Through the design of the energy storage circuit, the power management system can achieve self-starting without the need for a backup battery to provide starting current, which reduces the weight of the system, solves the problem of system service life caused by the backup battery, and reduces costs; (4) To address the problem that changes in the load circuit demand cause changes in the saturation level of the magnetic core, resulting in changes in the energy extraction power, the present invention controls the energy extraction interval through a microprocessor to maximize the energy extraction power in each energy extraction interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural diagram of a power management system provided by a certain embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. 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.

[0020] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0021] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two components. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are for illustrative purposes only, and do not indicate or imply that the system or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0022] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0023] In one embodiment, if Figure 1 As shown, the present invention provides a power management system, including: an electromagnetic field energy harvesting device 1, a rectifier circuit 2, a supercapacitor voltage hysteresis control circuit 3, an energy storage circuit 4, a microprocessor 5, a DC-DC voltage stabilizing circuit 6 and a load circuit 7; wherein, The electromagnetic field energy harvesting device 1 is used to collect the time-varying electromagnetic field generated by the power equipment and convert it into AC power; The rectifier circuit 2 is used to convert the AC power transmitted by the electromagnetic field energy harvesting device 1 into DC power by active rectification or passive rectification; The supercapacitor voltage hysteresis control circuit 3 is used to automatically switch between multiple power supply modes according to the size of the DC power transmitted by the rectifier circuit 2, so that the energy storage circuit 4 can be charged and discharged; The energy storage circuit 4 is used to store the DC power transmitted by the rectifier circuit 2, and enable the microprocessor 5 and the load circuit 7 through the DC-DC voltage regulator circuit 6 to achieve self-starting of the system; The microprocessor 5 is used to control the energy extraction interval and control the on and off of the rectifier circuit 2 so that the system can maximize the energy extraction power in each energy extraction interval.

[0024] Specifically, the power management system provided by the present invention captures the time-varying electromagnetic field around the power equipment through the electromagnetic field energy harvesting device 1, and converts it into AC power as one of the energy sources of the entire system, thereby realizing the effective utilization of the available energy in the environment; the AC power is converted into DC power in an active or passive manner through the rectifier circuit 2, providing a stable DC power supply for the subsequent circuit to ensure the normal operation of the subsequent circuit; a supercapacitor voltage hysteresis control circuit 3 is used to intelligently switch between multiple power supply modes according to the size of the DC power to optimize the charging and discharging process of the energy storage circuit 4, thereby improving the flexibility and efficiency of the system to ensure stable operation under different energy input conditions; The energy storage circuit 4 stores the DC power output by the rectifier circuit 2, and provides a stable power supply to the microprocessor 5 and the load circuit 7 through the DC-DC voltage regulator circuit 6. It is the core of energy storage and distribution, can realize the self-starting process of the system, and ensure the stable operation of the system when the energy fluctuates; the energy extraction interval of the entire system and the on and off of the rectifier circuit 2 are controlled by the microprocessor 5 (also known as the MCU) to maximize the energy extraction power in each energy extraction interval, so as to improve the overall efficiency and energy utilization of the system; in addition, the present invention also ensures the stability of the voltage provided to the microprocessor 5 and the load circuit 7 through the DC-DC voltage regulator circuit 6, and the load circuit 7 is the final user of the system energy.

[0025] The present invention collects and utilizes the time-varying electromagnetic field energy generated by the power equipment through the electromagnetic field energy harvesting device 1, thereby realizing green and sustainable energy utilization; the intelligent control of the supercapacitor voltage hysteresis control circuit 3 and the microprocessor 5 is adopted, so that the system can automatically adjust the power supply mode and energy harvesting power according to the energy input situation, thereby improving the overall efficiency and energy utilization rate of the system; and the design of the energy storage circuit 4 and the DC-DC voltage stabilizing circuit 6 can ensure the stable operation of the system during energy fluctuations, thereby improving the reliability and stability of the system; the system is suitable for various scenarios that require remote power supply or are difficult to access the traditional power grid, such as smart grids, Internet of Things devices, etc., and has broad application prospects and market potential.

[0026] In one embodiment, the electromagnetic field energy harvesting device 1 includes an energy harvesting coil and a magnetic core; wherein the primary side of the energy harvesting coil is connected to the power equipment, and the secondary side of the energy harvesting coil is connected to the rectifier circuit 2; the magnetic core includes a closed magnetic core composed of two magnetic core blocks.

[0027] Specifically, the present invention adopts a separable closed magnetic core composed of two magnetic core blocks, and the two ends of the two magnetic core blocks are smooth so that the connection between the two magnetic core blocks is smooth and easy to install. The closed magnetic core induces the alternating current of the power equipment to produce a time-varying magnetic field, causing the magnetic flux of the closed magnetic core to change, thereby generating alternating current at both ends of the energy harvesting coil. Such a setting can also make the electromagnetic field energy harvesting device 1 easier to install, and the magnetic field coupling efficiency of the closed magnetic core is improved compared to the non-closed magnetic core, thereby achieving an increase in energy harvesting power.

[0028] In one embodiment, the rectifier circuit 2 is a synchronous full-bridge rectifier circuit, which includes two PMOS tubes Q1 and Q2, two NMOS tubes Q3 and Q4, and four Schottky diodes D1, D2, D3, and D4; wherein the source of Q1 is connected to the source of Q2, the drain of Q1 and the drain of Q2 are connected to the drain of Q3 and the drain of Q4 respectively, the four MOS tubes are connected in sequence to form a full-bridge rectifier circuit, and the four Schottky diodes are connected in parallel with the four MOS tubes respectively; wherein the PMOS tube is a P-channel metal oxide semiconductor field effect transistor, and the NMOS is an N-channel metal oxide semiconductor field effect transistor, both of which are MOS tubes. The synchronous full-bridge rectifier circuit adopts two modes of passive rectification and active rectification, the active rectification adopts four MOS tubes for rectification, and the passive rectification adopts four Schottky diodes for rectification.

[0029] The rectifier circuit 2 is also used for: When the AC power is in a positive half cycle, Q1 and Q4 are controlled to be turned on to actively rectify the AC power to obtain DC power; when the AC power is in a negative half cycle, Q2 and Q3 are controlled to be turned on to actively rectify the AC power to obtain DC power; When the AC power is in the positive half cycle, D1 and D4 are controlled to perform passive rectification on the AC power to obtain DC power; when the AC power is in the negative half cycle, D2 and D3 are controlled to perform passive rectification on the AC power to obtain DC power.

[0030] Specifically, the present invention uses MOSFETs as the rectifying elements for active rectification, and controls the gates of the rectifier bridge MOSFETs through a low-power microprocessor 5 , thereby achieving control over the rectifying circuit 2 .

[0031] In order to control the start and end time of the rectifier bridge, the voltage at both ends of the magnetic core must first be sampled and analyzed by ADC, and then the conduction order of each MOSFET is controlled. If the voltage at both ends of the coil collected by ADC is directly compared to determine the conduction status of the two ends of the magnetic core, the voltage fluctuation may lead to wrong judgment and cause the control logic to be out of order. Therefore, the present invention defines U U,P , UL,P is the past value of the voltage between the upper and lower sides of the core coil and the ground, U U,C , U L,C It is the present value of the voltage between the upper and lower sides of the core coil and the ground. By comparing the present value with the past value, the rising and falling edges on each side can be found. After the comparison, the present value becomes the new past value, waiting for the next round of "present value" to arrive and be compared.

[0032] In this dynamic control, the upper side of the magnetic core is used as the energy entry point each time. When the rising edge on the upper side of the magnetic core is detected, it means that the positive half-cycle energy extraction has started. At this time, the magnetic core short-circuit state is first entered (this short circuit can be regarded as a transient behavior, which helps to improve the efficiency and performance of the system in the initial stage) until the full-bridge rectifier is turned on, and then enters the positive half-cycle energy extraction state. In the energy extraction state, the volt-second product of the magnetic core continues to increase. When the falling edge on the upper side of the magnetic core is detected, it means that the magnetic core has entered magnetic saturation or reached the end time of the energy extraction range. At this time, the positive half-cycle energy extraction ends and all MOSFETs are turned off. Similarly, the process of negative half-cycle energy extraction is similar to positive half-cycle energy extraction.

[0033] The present invention realizes active rectification of AC power by accurately controlling the on and off of PMOS tubes Q1, Q2 and NMOS tubes Q3, Q4, which can significantly reduce power consumption in the rectification process, thereby reducing rectification loss; and in the scheme, Schottky diodes D1, D2, D3, and D4 are also used for passive rectification, and the diodes are connected in parallel for assistance, so as to ensure that at the moment when MOSFET fails to be fully turned on or turned off, the continuity of the circuit can still be maintained, and current interruption or excessive reverse recovery current is avoided, thereby further improving the rectification efficiency; four MOSFETs and four Schottky diodes are integrated in a full-bridge rectification circuit, which simplifies the design and layout of the circuit, not only reduces the number and cost of components, but also improves the reliability and stability of the circuit.

[0034] In one embodiment, the energy storage circuit 4 includes a super capacitor and a voltage monitor; wherein the positive electrode of the super capacitor is connected to the input end of the voltage monitor, and the output end of the voltage monitor is respectively connected to the enable end of the microprocessor 5 and the load circuit 7; wherein the present invention selects a 500mF super capacitor, whose withstand voltage is 11V, the upper limit voltage is 5.04V, and the charging threshold is 3.88V; and the built-in voltage of the voltage monitor is 2.98V.

[0035] In one embodiment, the energy storage circuit 4 is further used for: receiving the DC power transmitted by the rectifier circuit 2 and charging the supercapacitor so that the supercapacitor stores energy; When it is detected that the voltage of the supercapacitor is greater than the built-in voltage of the voltage monitor, the voltage monitor is controlled to output a high level, and the microprocessor 5 and the load circuit 7 are connected to the system by enabling the DC-DC voltage regulator circuit 6, so that the system completes self-starting; When it is detected that the voltage of the supercapacitor is charged to the upper limit voltage, the rectifier circuit 2 is short-circuited, and the load circuit 7 is powered solely by the supercapacitor until the voltage of the supercapacitor drops to the charging threshold, and the DC power transmitted by the rectifier circuit 2 is received again to charge the supercapacitor.

[0036] Specifically, the supercapacitor in the present invention has the ability to charge and discharge quickly, can store a large amount of electrical energy in a short time, and release it quickly when needed, so that the system can provide stable electrical energy support through the supercapacitor when the power fails or is unstable, ensuring the normal operation of the microprocessor 5 and the load circuit 7; the charging and discharging process of the supercapacitor is accurately controlled by the voltage monitor, avoiding the damage to the supercapacitor caused by overcharging or overdischarging, and extending its service life. When the voltage of the supercapacitor is greater than the built-in voltage of the voltage monitor, the system can automatically start the DC-DC voltage stabilizing circuit 6, connect the microprocessor 5 and the load circuit 7 to the system, and realize intelligent self-starting; after the supercapacitor voltage is charged to the upper limit voltage, the system can automatically short-circuit the rectifier circuit 2, and the supercapacitor alone supplies power to the load circuit 7; when the supercapacitor voltage drops to the charging threshold, the system can receive the DC power transmitted by the rectifier circuit 2 again to charge the supercapacitor.

[0037] The intelligent power supply management method adopted by the present invention not only ensures the stable operation of the system, but also improves the energy utilization efficiency. At the same time, the design of the energy storage circuit 4 enables the system to provide emergency power support when the power fails or is unstable, avoiding the occurrence of system shutdown or data loss due to power problems. The coordinated work of the voltage monitor and the microprocessor 5 can monitor the voltage state of the supercapacitor in real time, and take corresponding measures in time to ensure the normal operation of the system, thereby enhancing the stability and reliability of the system; by integrating components such as the voltage monitor, the microprocessor 5 and the supercapacitor, there is no need for a backup battery to provide a starting current to achieve self-starting, and the energy storage circuit 4 also realizes efficient storage, management and utilization of electrical energy, simplifies the complex components and line connections in the traditional circuit design, reduces the weight of the system, solves the problem of system service life caused by the backup battery, and reduces the manufacturing cost of the system.

[0038] In one embodiment, the supercapacitor voltage hysteresis control circuit 3 includes an NMOS tube Q5, a hysteresis comparator 31 and a Schottky diode D5; wherein the positive input terminal of the hysteresis comparator 31 is connected to the positive electrode of the supercapacitor, the inverting input terminal of the hysteresis comparator 31 is connected to the reference voltage, the output terminal of the hysteresis comparator 31 is connected to the gate of Q5, the drain of Q5 is connected to the negative electrode of the supercapacitor, and the source of Q5 is connected to the anode of D5.

[0039] In one embodiment, the supercapacitor voltage hysteresis control circuit 3 is further used for: Setting the upper threshold voltage and the lower threshold voltage of the hysteresis comparator 31; When it is detected that the voltage of the supercapacitor rises to the upper threshold voltage, the hysteresis comparator 31 is controlled to output a high level and the Q5 tube is turned on, so that the DC power is short-circuited to the ground, so that the supercapacitor alone supplies power to the load circuit 7; When it is detected that the voltage of the super capacitor drops to the lower threshold voltage, the hysteresis comparator 31 is controlled to output a low level and the Q5 tube is turned off, so that the DC power can recharge the super capacitor.

[0040] Specifically, the present invention sets the upper and lower threshold voltages of the hysteresis comparator 31 to 5.04V and 3.88V respectively; when the voltage of the supercapacitor rises to the upper threshold voltage, the hysteresis comparator 31 is controlled to output a high level and the NMOS tube Q5 is turned on, and the induced current is short-circuited to the ground after passing through the rectifier circuit 2. At this time, the supercapacitor supplies power to the load alone; when the voltage of the supercapacitor drops to the lower threshold voltage, the hysteresis comparator 31 is controlled to output a low level and the NMOS tube Q5 is turned off, and the rectified DC power recharges the supercapacitor; so that after the energy extraction device is self-started, the energy source of the load circuit 7 is different under different energy extraction primary side current and supercapacitor voltage conditions.

[0041] The present invention ensures that the supercapacitor operates within a suitable voltage range through a hysteresis control mechanism, improves energy utilization efficiency, and helps reduce system instability caused by voltage fluctuations. Since the hysteresis comparator 31 has a hysteresis characteristic, even if the voltage fluctuates within a certain range, it will not trigger frequent charge and discharge switching, thereby avoiding the impact and damage to the system caused by frequent switching; a simple component combination (NMOS tube Q5, hysteresis comparator 31 and Schottky diode D5) is used to achieve precise control of the supercapacitor voltage. Compared with traditional complex circuits, this design reduces the complexity of the circuit and the manufacturing cost.

[0042] In one embodiment, the microprocessor 5 is further configured to: Receiving the DC power transmitted by the rectifier circuit 2 to determine the peak position of the DC power, and determining the start and end time of the energy extraction interval based on the DC power to control the opening and closing of the rectifier circuit 2; the energy extraction interval is configured to be symmetrical about the peak position; The load circuit 7 is monitored in real time, and when the load circuit 7 changes, the actual energy extraction interval of the next cycle is obtained to compare with the preset length; If the two are the same, the current turn-on time of the rectifier circuit 2 is maintained at the optimal value, and energy is continued to be drawn in the next half cycle; if the two are not equal, the actual energy drawing interval is assigned to the system to update the current turn-on time of the rectifier circuit 2 through the system, and in each half cycle, the turn-on time of the rectifier circuit 2 is cyclically updated according to the real-time changes of the load circuit 7 to draw energy, so that the system can maximize the energy drawing power in each of the energy drawing intervals.

[0043] Specifically, microprocessor 5 uses an ultra-low power consumption microprocessor to control the energy extraction interval (also called the energy extraction window), so that the energy extraction window is as symmetrical as possible about the peak value of the primary side AC power, thereby increasing the average value of the secondary side current within the energy extraction window time, thereby achieving an increase in energy extraction power.

[0044] When it is detected that the load circuit 7 changes and causes the saturation degree of the magnetic core to change, that is, when T / 2 of the positive half cycle ends, the microprocessor 5 obtains the actual energy extraction interval of the next cycle and compares it with the system preset length. If the two are the same, it means that the full-bridge rectifier start time is the optimal value, and the electromagnetic field energy extraction device 1 will enter the next half cycle to continue to extract energy. If they are not equal, the actual energy extraction interval is assigned to the system. At this time, the system updates the preset full-bridge rectifier start time, and then enters the negative half cycle to extract energy. Therefore, the actual energy extraction interval detected by the system in the negative half cycle will be the energy extraction interval of the positive half cycle. This design ensures that the subsequent energy collection cycle will update the start time of the full-bridge rectifier in each half cycle of the primary side AC, so that the energy extraction system can always ensure that the energy extraction interval is in the optimal position when the primary side current changes, thereby maximizing the magnetic field energy extraction power.

[0045] The control process of the microprocessor 5 on the rectifier circuit 2 is as follows: the ACT signal is the output signal of the microprocessor 5. When the ACT signal is at a low level, the gate potential of Q1 is pulled down to the ground, Q1 is turned on, and then the gate potential of Q1 is pulled up to V0, so as to achieve self-locking of Q1, and the gate potential of Q4 is pulled up to V0, Q4 is turned on, so that the gate potential of Q4 is pulled down to the ground, and then Q4 is turned off; when the microprocessor 5 is powered on, the full-bridge rectifier MOSFET is driven by the microprocessor 5 to achieve synchronous rectification. If in the dynamic In the control stage, the microprocessor 5 outputs a signal ACT of high potential, so that the gate potential of Q1 is pulled up to V0, and the gate potential of Q4 is pulled down, thereby realizing the self-locking of Q1 and Q4. At this time, the microprocessor 5 directly outputs the gate signal for controlling Q1 and Q4; and Q2 and Q3, as another phase full-bridge rectifier circuit, have the same control configuration as Q1 and Q4 respectively. Through the control of the microprocessor 5 and the drive circuit, the MOSFETs can be freely turned on and off, thereby realizing the control of the rectifier circuit 2.

[0046] If the primary side AC frequency is 50Hz during the energy extraction experiment, its half cycle is 10ms. According to the principle that the energy extraction window is as symmetrical as possible about the maximum value of the primary side AC, the full-bridge rectifier opening time t d and energy window T W The following relationship exists: In the formula, t H It is the time difference between the opening time of the energy extraction window and the zero-crossing point of the primary-side sinusoidal current caused by the current of the load circuit 7 leading the primary-side current.

[0047] The enabling control process of the microprocessor 5 is as follows: the window cycle control of the magnetic field energy acquisition takes the energy acquisition on the upper side of the magnetic core as the entry point each time. When the rising edge on the upper side of the magnetic core is detected, it represents the start of energy acquisition. At this time, the upper side energy acquisition short-circuit state is first entered. At this time, the MCU controls Q1 and Q2 to be turned off, and the magnetic core is short-circuited by turning on NMOS tubes Q3 and Q4 to close the energy acquisition window; at the same time, the first timer and the second timer built into the MCU are turned on. At this time, since the magnetic core coil is short-circuited, volt-seconds cannot be accumulated until the timing value t1 of the first timer reaches the system preset full-bridge rectifier start time t d. The first timer is completed and the upper side energy acquisition starts. At this time, Q2 and Q3 are turned off and Q1 and Q4 are turned on, and the built-in counter of the MCU is enabled. It should be noted that in order to avoid the MOSFETs of the same bridge arm of the full-bridge rectifier being turned on at the same time, Q3 must be turned off first and then Q1 is turned on. At this time, the core volt-seconds continue to accumulate until the falling edge on the upper side of the core is detected, which means that the core has entered magnetic saturation. At this time, the core enters the upper side energy acquisition end state and all MOSFETs will be turned off. At the same time, the actual energy acquisition window time length t2 is obtained through the counter, and it is compared with the window time preset by the system. If the two are the same, it means that the full-bridge rectifier opening time is the optimal value, and the magnetic field energy acquisition will enter the second half cycle of the primary side AC to continue to acquire energy; if they are not equal, the actual energy acquisition window time is assigned to the system. At this time, the system updates the preset full-bridge rectifier opening time, and then circulates to enter the lower side energy acquisition.

[0048] The present invention controls the energy extraction interval through the microprocessor 5 to maximize the energy extraction power in each energy extraction interval to cope with the problem of changes in the energy extraction power caused by changes in the core saturation degree due to changes in load demand; by precisely controlling the opening and closing time of the rectifier circuit 2, unnecessary current shocks and voltage fluctuations can be reduced, thereby reducing the loss of the rectifier circuit 2 and its related equipment.

[0049] In one embodiment, the supercapacitor voltage hysteresis control circuit 3 is further used for: receiving the DC power transmitted by the rectifier circuit 2, and comparing the DC power with a critical current; the critical current is a primary side current that the DC power needs to meet to maintain the charging current of the load circuit 7; When it is detected that the DC power is greater than the critical current and the voltage of the supercapacitor is not less than the built-in voltage and less than the upper limit voltage, the hysteresis comparator 31 is controlled to output a low level and the Q5 tube is turned off, so that the microprocessor 5 starts to control energy acquisition and the system switches to a mode in which the load circuit 7 is powered solely by the DC power; When it is detected that the DC power is greater than the critical current and the voltage of the supercapacitor is greater than the upper limit voltage, the hysteresis comparator 31 is controlled to output a high level and enable the Q5 tube to be turned on, so that the microprocessor 5 controls the rectifier circuit 2 to turn off the active rectification and switches the system to a mode in which the supercapacitor is used to supply power to the load circuit 7 alone; When it is detected that the DC power is less than the critical current, the hysteresis comparator 31 is controlled to output a low level and the Q5 tube is enabled to be turned off, so that the microprocessor 5 controls the rectifier circuit 2 to start active rectification and switches the system to a mode in which the load circuit 7 is powered by a mixed supply of the DC power and the super capacitor.

[0050] Specifically, in the entire power management circuit, the load circuit 7 has multiple working modes. The present invention defines the critical current as the primary current of the magnetic field energy that can just maintain the charging current of the load. At this time, the supercapacitor voltage will be maintained at 2.98 V; then the supercapacitor voltage hysteresis control circuit 3 is also used to: detect that the DC power is greater than the critical current and the supercapacitor voltage V CAP Satisfy 2.98V≤V CAP <5.04V, the hysteresis comparator 31 is controlled to output a short-circuit signal of low potential, the short-circuit Q5 is turned off, the microprocessor 5 starts to control the energy extraction, and the electromagnetic field energy extraction device 1 supplies power to the load circuit 7 alone; when it is detected that the DC power is greater than the critical current and the supercapacitor voltage V CAP When it is greater than 5.04V, the hysteresis comparator 31 is controlled to output a short-circuit signal of a high potential, the short-circuit Q5 is turned on, the microprocessor 5 controls the active rectification to be turned off, and the supercapacitor supplies power to the load circuit 7 alone; when the DC power is less than the critical current, the hysteresis comparator 31 is controlled to output a short-circuit signal of a low potential, the short-circuit Q5 is turned off, the microprocessor 5 starts the active rectification, the electromagnetic field energy harvesting device 1 and the supercapacitor provide mixed power to the load circuit 7, and the supercapacitor supplies power to the load until the voltage drops to 2.88V, at which time the voltage monitor outputs a low potential, the downstream circuit is turned off, and the system re-enters self-start.

[0051] In the process of electromagnetic field energy extraction and power supply, the present invention controls the charging and discharging process of the supercapacitor through the supercapacitor voltage hysteresis control circuit 3 according to the current fluctuation of the transmission line, and realizes automatic switching of the three power supply modes by judging the magnitude of DC power and the supercapacitor voltage, thereby meeting the demand for stable and continuous power supply to the load.

[0052] In one embodiment, the load circuit 7 includes a charging chip and a load, and the load is a thin film battery; the DC-DC voltage regulator circuit 6 is used to provide a constant power supply to the charging chip and the microprocessor 5 respectively.

[0053] Specifically, the load circuit 7 protects the load through the charging chip, and the DC-DC voltage regulator circuit 6 provides 5V and 3.3V voltages respectively. It provides a 5V constant voltage power supply to the charging chip through the 5V voltage regulator chip Buck-Boost chip, and provides a 3.3V constant voltage power supply to the low-power microprocessor 5 through the 3.3V voltage regulator chip LDO chip.

[0054] In addition, by comparing the traditional rectification method under different loads with the rectification method controlled by a microprocessor program of the present invention, it is found that the rectification method of the present invention achieves a 76% increase in energy extraction power; at the same time, compared with the traditional rectification method, the power index of the present invention is increased by 1.7 times.

[0055] It should be noted that each module in the above power management system can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0056] In summary, the present invention relates to the field of power management technology, and discloses a power management system, including an electromagnetic field energy harvesting device for collecting time-varying electromagnetic fields generated by power equipment and converting them into alternating current power, a rectifier circuit for converting alternating current power into direct current power by active or passive rectification, a supercapacitor voltage hysteresis control circuit for automatically switching between multiple power supply modes according to the size of the direct current power so that the energy storage circuit can be charged and discharged, an energy storage circuit for storing direct current power and enabling a microprocessor and a load circuit through a DC-DC voltage regulator circuit to achieve self-starting of the system, a microprocessor for controlling the energy harvesting interval and controlling the on and off of the rectifier circuit so that the system can achieve maximum energy harvesting power in each energy harvesting interval. The system can self-start, has high energy harvesting power, and can provide stable and continuous power supply to the load, and has high reliability and stability.

[0057] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above-mentioned embodiments only express several preferred implementation modes of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in the technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be based on the protection scope of the claims.

Claims

1. A power management system, characterized in that: include: Electromagnetic field energy harvesting device, rectifier circuit, supercapacitor voltage hysteresis control circuit, energy storage circuit, microprocessor, DC-DC voltage stabilizing circuit and load circuit; wherein, The electromagnetic field energy harvesting device is used to collect the time-varying electromagnetic field generated by the power equipment and convert it into AC power; The rectifier circuit is used to convert the AC power transmitted by the electromagnetic field energy harvesting device into DC power by active rectification or passive rectification; The supercapacitor voltage hysteresis control circuit is used to automatically switch between multiple power supply modes according to the size of the DC power transmitted by the rectifier circuit, so as to charge and discharge the energy storage circuit; The energy storage circuit is used to store the DC power transmitted by the rectifier circuit, and enable the microprocessor and the load circuit through the DC-DC voltage regulator circuit to achieve self-starting of the system; The microprocessor is used to control the energy extraction interval and control the on and off of the rectifier circuit so that the system can maximize the energy extraction power in each energy extraction interval.

2. A power management system according to claim 1, characterized in that: The electromagnetic field energy harvesting device includes an energy harvesting coil and a magnetic core; wherein the primary side of the energy harvesting coil is connected to the power equipment, and the secondary side of the energy harvesting coil is connected to the rectifier circuit; the magnetic core includes a closed magnetic core composed of two magnetic core blocks.

3. A power management system according to claim 1, characterized in that: The rectifier circuit is a synchronous full-bridge rectifier circuit, which includes two PMOS tubes Q1 and Q2, two NMOS tubes Q3 and Q4, and four Schottky diodes D1, D2, D3, and D4; wherein the source of Q1 is connected to the source of Q2, the drain of Q1 and the drain of Q2 are respectively connected to the drain of Q3 and the drain of Q4, the four MOS tubes are connected in sequence to form a full-bridge rectifier circuit, and the four Schottky diodes are respectively connected in parallel with the four MOS tubes; The rectifier circuit is also used for: When the AC power is in a positive half cycle, Q1 and Q4 are controlled to be turned on to actively rectify the AC power to obtain DC power; when the AC power is in a negative half cycle, Q2 and Q3 are controlled to be turned on to actively rectify the AC power to obtain DC power; When the AC power is in the positive half cycle, D1 and D4 are controlled to perform passive rectification on the AC power to obtain DC power; when the AC power is in the negative half cycle, D2 and D3 are controlled to perform passive rectification on the AC power to obtain DC power.

4. A power management system according to claim 3, characterized in that: The energy storage circuit includes a super capacitor and a voltage monitor; wherein the positive electrode of the super capacitor is connected to the input end of the voltage monitor, and the output end of the voltage monitor is respectively connected to the enable end of the microprocessor and the load circuit.

5. A power management system according to claim 4, characterized in that: The energy storage circuit is also used for: receiving the DC power transmitted by the rectifier circuit and charging the supercapacitor so that the supercapacitor stores energy; When it is detected that the voltage of the supercapacitor is greater than the built-in voltage of the voltage monitor, the voltage monitor is controlled to output a high level, and the microprocessor and the load circuit are connected to the system by enabling the DC-DC voltage regulator circuit, so that the system completes self-starting; When it is detected that the voltage of the supercapacitor is charged to the upper limit voltage, the rectifier circuit is short-circuited, and the load circuit is powered solely by the supercapacitor until the voltage of the supercapacitor drops to the charging threshold, and the DC power transmitted by the rectifier circuit is received again to charge the supercapacitor.

6. A power management system according to claim 5, characterized in that: The supercapacitor voltage hysteresis control circuit includes an NMOS tube Q5, a hysteresis comparator and a Schottky diode D5; wherein the positive input terminal of the hysteresis comparator is connected to the positive electrode of the supercapacitor, the inverting input terminal of the hysteresis comparator is connected to the reference voltage, the output terminal of the hysteresis comparator is connected to the gate of Q5, the drain of Q5 is connected to the negative electrode of the supercapacitor, and the source of Q5 is connected to the anode of D5.

7. A power management system according to claim 6, characterized in that: The supercapacitor voltage hysteresis control circuit is also used for: Setting the upper threshold voltage and the lower threshold voltage of the hysteresis comparator; When it is detected that the voltage of the supercapacitor rises to the upper threshold voltage, the hysteresis comparator is controlled to output a high level and the Q5 tube is turned on, so that the DC power is short-circuited to the ground, so that the supercapacitor alone supplies power to the load circuit; When it is detected that the voltage of the super capacitor drops to the lower threshold voltage, the hysteresis comparator is controlled to output a low level and the Q5 tube is turned off, so that the DC power can recharge the super capacitor.

8. A power management system according to claim 6, characterized in that: The microprocessor is further used for: Receiving the DC power transmitted by the rectifier circuit to determine the peak position of the DC power, and determining the start and end time of the energy extraction interval based on the DC power to control the opening and closing of the rectifier circuit; the energy extraction interval is configured to be symmetrical about the peak position; Performing real-time monitoring on the load circuit, and when the load circuit changes, obtaining the actual energy extraction interval of the next cycle to compare with the preset length; If the two are the same, the current rectifier circuit turn-on time is maintained at the optimal value, and energy is continued to be drawn in the next half cycle; if the two are not equal, the actual energy drawing interval is assigned to the system to update the current rectifier circuit turn-on time through the system, and in each half cycle, the rectifier circuit turn-on time is cyclically updated according to the real-time changes of the load circuit to draw energy, so that the system can maximize the energy drawing power in each energy drawing interval.

9. A power management system according to claim 8, characterized in that: The supercapacitor voltage hysteresis control circuit is also used for: receiving the DC power transmitted by the rectifier circuit, and comparing the DC power with a critical current; the critical current being a primary-side current at which the DC power satisfies a charging current of the load circuit; When it is detected that the DC power is greater than the critical current and the voltage of the supercapacitor is not less than the built-in voltage and less than the upper limit voltage, the hysteresis comparator is controlled to output a low level and the Q5 tube is turned off, so that the microprocessor starts to control energy acquisition and the system switches to a mode in which the load circuit is powered solely by the DC power; When it is detected that the DC power is greater than the critical current and the voltage of the supercapacitor is greater than the upper limit voltage, the hysteresis comparator is controlled to output a high level and enable the Q5 tube to be turned on, so that the microprocessor controls the rectifier circuit to turn off active rectification and switches the system to a mode in which the supercapacitor is used to supply power to the load circuit alone; When it is detected that the DC power is less than the critical current, the hysteresis comparator is controlled to output a low level and the Q5 tube is enabled to be turned off, so that the microprocessor controls the rectifier circuit to start active rectification and switches the system to a mode in which the load circuit is supplied with a mixed power by the DC power and the supercapacitor.

10. A power management system according to claim 1, characterized in that: The load circuit includes a charging chip and a load, wherein the load is a thin film battery; the DC-DC voltage stabilizing circuit is used to provide a constant power supply to the charging chip and the microprocessor respectively.

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