A standby mode control method based on a magnetic wireless fast charging power bank

Abstract

The application relates to the technical field of mobile power sources, and discloses a standby mode control method based on a magnetic wireless fast-charging mobile power source, a spiral coil is divided into a driving section and an induction section which are electrically independent and magnetically coupled through a 0.2mm insulation gap, and the method comprises the following steps: when the mobile power source is in a standby state, triggering a wake-up detection at fixed time intervals, which comprises: injecting a square wave detection pulse into the induction section; synchronously collecting mutual inductance voltage values of the driving section timing at a preset sampling period; calculating average voltage values of the mutual inductance voltage values; and comparing the average voltage values with a voltage threshold value to wake up the mobile power source. The application realizes high-sensitivity wake-up detection in a low-power-consumption state, effectively avoids false wake-up and energy waste, and improves the intelligent control level and overall energy efficiency performance of the magnetic wireless fast-charging mobile power source.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mobile power supply, more particularly, it relates to a standby mode control method based on a magnetic wireless fast charging mobile power supply. BACKGROUND

[0002] In the current rapid development of the mobile terminal wireless charging market, the magnetic wireless fast charging mobile power supply gradually becomes the first choice for users to go out for power supply, thanks to its convenient experience of being able to charge immediately without cables. However, unlike conventional wired mobile power supplies, wireless fast charging mobile power supplies must remain in standby mode most of the time to monitor whether there are charging devices nearby, and when the user attaches a mobile phone or earphone box to the coil, the power level is instantly awakened and started. Since the wireless charging coil is not suitable for continuous power supply in standby state, otherwise it will cause self-discharge to increase, static power consumption of the whole machine to rise from milliamperes to several milliamperes or even tens of milliamperes, and the available time of the mobile power supply will be greatly shortened; but if the detection mechanism is too conservative or the response is too slow, the scenario of attaching but not charging will occur, which will damage the user experience.

[0003] The prior art adopts the following methods:

[0004] Continuous excitation combined with current or voltage polling: a small current is continuously driven into the coil or the oscillation is maintained, and the MCU samples the voltage or current change between the two ends of the coil at a high frequency to detect the coupling; this method has low hardware requirements, but the standby power consumption often reaches several milliamperes, which cannot meet the long-time offline use.

[0005] Additional sensor detection: Hall elements, optical switches or infrared sensing modules are arranged around the coil to detect the magnetic field strength or visible light signal to determine the proximity of the terminal; although the main control and power level can be turned off to reduce self-consumption, the additional sensors increase the cost, volume and board complexity, and are easily disturbed by external metal foreign objects or environmental light, which has insufficient reliability.

[0006] Resonance monitoring method: maintain low-power resonance of the coil in standby mode, and measure the drift of the resonance frequency or impedance curve in real time to determine the coupling; this method has high detection sensitivity, but the power amplifier needs to work continuously to maintain resonance, and the quality factor Q value and frequency stability of the coil are required to be very high, which is difficult to achieve high-precision sampling under microampere standby.

[0007] The above-mentioned solutions all have the problem that they cannot be compatible with high sensitivity and fast response, resulting in frequent false awakenings or false awakenings. SUMMARY

[0008] The present application provides a standby mode control method based on a magnetic wireless fast charging mobile power supply, which solves the technical problems raised in the background art.

[0009] The application provides a standby mode control method based on a magnetic wireless fast charging power bank, a spiral coil is divided into a driving segment and an inductive segment which are electrically independent and magnetically coupled through a 0.2 mm insulation gap, and the following steps are sequentially performed:

[0010] When the power bank is in a standby state, a wake-up detection is triggered at a fixed time interval, including: injecting a square wave detection pulse into the inductive segment;

[0011] Synchronously collecting mutual inductance voltage values of the driving segment timing at a preset sampling period;

[0012] Calculating an average voltage value of the mutual inductance voltage values, comparing the average voltage value with a voltage threshold value, and waking up the power bank.

[0013] Further, the square wave detection pulse includes an amplitude Ip and a falling edge time tr.

[0014] Further, the mutual inductance voltage values of the driving segment timing are synchronously collected at a preset sampling period, including:

[0015] Within the falling edge time of the square wave detection pulse, the mutual inductance voltage values of the driving segment on the inductive segment are collected at a preset sampling period, and the calculation formula of the mutual inductance voltage values is as follows:

[0016]

[0017] For the square wave detection pulse: ;

[0018] Wherein, Vm represents the mutual inductance voltage value, Rs represents the resistance value of a sampling resistor used to obtain Vm and connected in series with the driving segment, k represents the coupling coefficient of the driving segment and the inductive segment, Lp represents the self-inductance of the driving segment, and Ls represents the self-inductance of the inductive segment.

[0019] Further, the coupling coefficient of the driving segment and the inductive segment is obtained as follows:

[0020] Step 41, using an LCR meter to respectively measure the self-inductances Lp and Ls of the driving segment and the inductive segment at 100 kHz;

[0021] Step 42, applying a 100 kHz sine wave to the driving segment;

[0022] Step 43, controlling the inductive segment to be open, and measuring the inductive voltage SV of the inductive segment through an oscilloscope;

[0023] Step 44, measuring the driving segment current PI;

[0024] Step 45, calculating the mutual inductance of the driving segment and the inductive segment, as follows:

[0025]

[0026] Wherein, M represents mutual inductance of the driving section and the induction section, f is 100 kHz;

[0027] Step 46, calculate the coupling coefficient of the driving section and the induction section, as follows:

[0028]

[0029] Wherein, k represents the coupling coefficient of the driving section and the induction section.

[0030] Further, the average voltage value of the mutual inductance voltage value is calculated, including:

[0031] Load the sliding time window, the length of the sliding time window is less than the length of the wake-up detection;

[0032] Based on the sliding time window, the voltage value of the sliding extraction timing is extracted, and the average voltage value of the extracted voltage value is extracted.

[0033] Further, the voltage threshold is obtained as follows:

[0034] Control the mobile power supply in the upper state, and repeat steps 41 to 46 to obtain the peak coupling coefficient of the driving section and the induction section;

[0035] Calculate the difference between the peak coupling coefficient and the coupling coefficient to obtain the sensitive coupling coefficient;

[0036] In the calculation formula of the mutual inductance voltage value, the coupling coefficient is replaced by the sensitive coupling coefficient, and the voltage threshold is calculated.

[0037] Further, the mobile power supply is woken up, including:

[0038] If the average voltage value is greater than the voltage threshold, mark 1;

[0039] When the 1 is marked for a preset number of times in succession, the mobile power supply is woken up.

[0040] The beneficial effects of the present application are that by dividing the spiral coil into the driving section and the induction section which are electrically independent and magnetically coupled, and injecting square wave detection pulses at fixed time intervals in the standby state, synchronously collecting mutual inductance voltage values and comparing with the voltage threshold, whether to wake up the mobile power supply is judged, the method not only realizes high sensitivity wake-up detection in low power consumption state, but also effectively avoids false wake-up and energy waste, and improves the intelligent control level and overall energy efficiency performance of the magnetic wireless fast charging mobile power supply. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a flow chart of a standby mode control method based on a magnetic wireless fast charging mobile power supply of the present application. DETAILED DESCRIPTION

[0042] The subject matter described herein will now be discussed in connection with example embodiments. It should be understood that the discussion of these embodiments is merely intended to provide an overview of the subject matter described herein and to aid in the understanding thereof, and is not intended to limit the scope of the subject matter described herein. Changes to the function and arrangement of elements can be made without departing from the scope of the subject matter described herein. Various examples can omit, substitute, or add various procedures or components as appropriate. Also, the description described in connection with some examples can be applicable to other examples.

[0043] As shown in Figure 1 A standby mode control method based on a magnetic wireless fast-charging power bank, a spiral coil is divided into a driving segment and an induction segment which are electrically independent and magnetically coupled through a 0.2mm insulation gap, and the following steps are executed in sequence:

[0044] When the power bank is in a standby state, a wake-up probe is triggered at a fixed time interval, including: injecting a square wave probe pulse into the induction segment;

[0045] Synchronously collecting mutual inductance voltage values of the driving segment timing at a preset sampling period;

[0046] Calculating the average voltage value of the mutual inductance voltage value, comparing the average voltage value with the voltage threshold value, and waking up the power bank.

[0047] It should be noted that the whole spiral coil is accurately divided into two electrically independent and magnetically coupled parts: the driving segment and the induction segment. There is an insulation gap of about 0.2mm between the two, which ensures complete isolation at the DC level (DC resistance tends to infinity), thereby eliminating the additional power consumption caused by coil leakage in the traditional standby mode; under the action of alternating magnetic field, the two coils can still be strongly coupled through the shared magnetic flux path, and the induction segment can sensitively capture the transient magnetic field changes of the driving segment. With the aid of a self-coupled transformer structure, the system only needs to apply a micro-watt level short pulse excitation to the induction segment, which can complete real-time monitoring of the terminal adsorption state at extremely low power consumption. Compared with continuously powering the Hall sensor or photoelectric device, this method sharply reduces the standby average current from the milliamper level to the microampere level, significantly prolonging the static endurance time of the power bank. In addition, the segmented design eliminates the need for pull-up resistors, filter capacitors and additional driving chips required by traditional independent sensors, not only simplifying the PCB layout and component list, reducing BOM cost, but also improving the consistency of assembly and debugging. Paste a special ferrite ring under the induction segment, which can effectively constrain the main direction of magnetic flux to be axial, avoiding the mis-triggering caused by lateral or external metal interference, further improving the reliability and stability of the system in complex use environment.

[0048] In an embodiment of the present application, the square wave probe pulse includes: amplitude Ip and falling edge time tr.

[0049] It should be noted that in the standby wake-up mechanism, the square wave detection pulse is injected into the inductive section, and the core purpose is to use the electromagnetic induction law to quickly convert the mutual inductance change between the mobile power supply and the mobile phone coil due to the fit into a measurable voltage signal. Specifically, when the mobile phone magnet coil approaches the driving section of the mobile power supply, the coupling coefficient between the two will instantaneously change slightly; by injecting a square wave pulse into the inductive section for a short time and measuring the induced voltage generated, the coupling fluctuation can be captured with extremely high sensitivity, thereby triggering the subsequent wake-up process.

[0050] It should be noted that the square wave detection pulse completes most of the mutual inductance excitation and induced voltage generation in the falling edge phase (defined as tr, which is the time for the current to drop from the peak value Ip to 0). Since The voltage amplitude output by the inductive section also rises at the moment of the falling edge, significantly improving the signal-to-noise ratio and ensuring that reliable detection results can still be obtained in weak coupling conditions.

[0051] It should be noted that in order to reduce the overall standby power consumption to the micro-watt level, a low-duty-cycle square wave detection pulse is preferably used, such as a 50Hz repetition frequency and a 4μs pulse width triggered periodically. When the inductive section self-inductance is Ls and the pulse peak current is Ip (preferably 1mA), the energy released by a single pulse can be calculated as Combined with the 200ns falling edge tr, the average energy consumption per unit time is strictly controlled in the micro-watt level.

[0052] In an embodiment of the present application, the mutual inductance voltage value of the driving section timing is synchronously collected at a preset sampling period, including:

[0053] During the falling edge time of the square wave detection pulse, the mutual inductance voltage value of the driving section on the inductive section is collected at a preset sampling period, and the calculation formula of the mutual inductance voltage value is as follows:

[0054]

[0055] For the square wave detection pulse: ;

[0056] Wherein, Vm represents the mutual inductance voltage value, Rs represents the resistance value of the sampling resistance used to obtain Vm in series with the driving section, k represents the coupling coefficient of the driving section and the inductive section, Lp represents the self-inductance of the driving section, Ls represents the self-inductance of the inductive section, represents the current rate of change.

[0057] It should be noted that the sampling is started at the falling edge of the square wave detection pulse (the falling edge tr of the square wave detection pulse is the stage where the current drops from Ip to 0), because at this time The maximum mutual inductance induced voltage Vm has the highest amplitude and the best signal-to-noise ratio.

[0058] The current rate of change of the falling edge of the square wave (e.g. 1 mA current is returned to zero in 200 ns, the rate of change is 5x10 6 A / s), reflecting the basic amplitude of the mutual inductance voltage value.

[0059] k represents the coupling coefficient of the driving section and the inductive section.

[0060] Rs represents the sampling resistance (preferably 0.5 ohms) connected in series with the driving section, to convert the induced current into a measurable millivolt-level voltage.

[0061] The traditional wake-up scheme relies on an independent sensor (Hall element), while the application reuses the mutual inductance characteristics of the charging coil itself: through the accurate sampling of the falling edge of the square wave, the magnetic coupling change is taken as a voltage signal. The coordinated design of Ip, tr and Rs in the formula realizes the balance between micro-watt power consumption and high sensitivity detection.

[0062] In an embodiment of the application, the coupling coefficient of the driving section and the inductive section is obtained as follows:

[0063] Step 41, using an LCR meter to measure the self-inductance Lp and Ls of the driving section and the inductive section respectively at 100 kHz;

[0064] Step 42, applying a 100 kHz sinusoidal wave to the driving section;

[0065] Step 43, controlling the inductive section to be open-circuit, and measuring the induced voltage SV of the inductive section by an oscilloscope;

[0066] Step 44, measuring the driving section current PI;

[0067] Step 45, calculating the mutual inductance of the driving section and the inductive section as follows:

[0068]

[0069] Where M represents the mutual inductance of the driving section and the inductive section, and f is 100 kHz;

[0070] Step 46, calculating the coupling coefficient of the driving section and the inductive section as follows:

[0071]

[0072] Where k represents the coupling coefficient of the driving section and the inductive section.

[0073] It should be noted that the coupling coefficient k describes the tightness of the magnetic coupling of the driving section and the induction section, but the magnetic characteristics cannot be directly measured. The application converts the magnetic coupling into an electrical signal calculation through the path of applying an alternating current signal → measuring the induced voltage → deriving the magnetic parameters, to realize accurate quantification:

[0074] Mutual inductance M is the core parameter of magnetic coupling, and the relationship between induced voltage SV and mutual inductance M is: ; and through the definition of coupling coefficient , the degree of magnetic coupling is converted into a dimensionless parameter.

[0075] It should be noted that in the present application, the mutual inductance coupling coefficient k is measured by specifically selecting a signal source frequency near 100 kHz (for example, in the range of 80 kHz to 205 kHz as specified in the Qi protocol) to simulate the magnetic field environment in the actual wireless charging scenario, ensuring that the measured self-inductance of the driving section and the self-inductance of the induction section are highly consistent with the actual working state, while avoiding errors introduced by frequency deviation.

[0076] In order to obtain a more accurate linear relationship between mutual inductance and induced voltage, a sine wave is preferably used for calibration instead of a pulse signal: the sine wave has the advantages of stable amplitude, controllable phase, and strong periodicity, and the amplitude and phase parameters of the coil voltage and current can be accurately measured through an oscilloscope or a lock-in amplifier, thereby providing reliable data for subsequent derivation of mutual inductance.

[0077] During the measurement process, the induction section needs to be kept open to eliminate the interference of the reverse magnetic field generated by the induced current in the self-loop. Thus, the induction section only serves as a magnetic field detection unit, and there is no secondary influence of current load on the primary magnetic field, so that the voltage signal SV collected is completely derived from the magnetic field coupling of the driving section, ensuring the accuracy of the measurement results and avoiding the pollution of additional coupling paths or parasitic coupling to the data.

[0078] The expression of the coupling coefficient k is:

[0079]

[0080] It is a kind of normalization processing method, which eliminates the influence of the self-inductance size difference of Lp and Ls two sections of coils on the coupling coefficient, so that the coupling coefficient k only reflects the relative tightness of the two coils in the magnetic circuit. The value of k ranges from 0 to 1, and the closer to 1, the tighter the magnetic field coupling of the two coils, and the higher the coupling efficiency; the closer to 0, the looser the coil coupling or the failure to form an effective magnetic flux path.

[0081] In an embodiment of the present application, the average voltage value of the mutual inductance voltage value is calculated, comprising:

[0082] A sliding time window is loaded, and the length of the sliding time window is less than the length of the wake-up detection;

[0083] The voltage value extracted based on the sliding time window is slid, and the average voltage value of the extracted voltage value is extracted.

[0084] It should be noted that the measurement of mutual inductance voltage is affected by circuit thermal noise, electromagnetic interference (such as wireless signals), and single sampling value may appear random fluctuations (such as suddenly jumping above the threshold value, and the actual mobile phone is not aligned). Through the sliding time window and the average value calculation, the instantaneous interference can be smoothed, and the wake-up decision is based on the continuous signal trend rather than accidental fluctuations.

[0085] In an embodiment of the present application, the voltage threshold is obtained as follows:

[0086] The mobile power supply is controlled to be in the upper state, and steps 41 to 46 are repeatedly executed to obtain the peak coupling coefficient of the driving section and the inductive section;

[0087] The difference between the peak coupling coefficient and the coupling coefficient is calculated to obtain the sensitive coupling coefficient;

[0088] In the calculation formula of mutual inductance voltage, the coupling coefficient is replaced by the sensitive coupling coefficient, and the voltage threshold is calculated.

[0089] It should be noted that the mobile power supply is switched to the upper state (i.e. continuously output power, coil in full excitation state), and steps 41 to 46 are repeatedly executed. Under the condition of known frequency 100kHz, the self-inductance is measured by LCR meter, the induced voltage is measured by oscilloscope and sampling resistor, and the maximum mutual inductance coefficient between the driving section and the inductive section is calculated by combining the driving current. Then the peak coupling coefficient is obtained from the maximum mutual inductance coefficient and the respective self-inductance.

[0090] In actual standby wake-up, the coil coupling may be slightly lower than the peak coupling due to distance, alignment, etc. The difference between the peak coupling coefficient obtained in the previous steps and the normal measured coupling coefficient (step 46) is obtained. Thus, the sensitive coupling coefficient is obtained, which represents the minimum coupling increment required for reliable identification under close conditions.

[0091] Finally, the original coupling coefficient k in the formula is replaced by the sensitive coupling coefficient Δk, and is brought into the mutual inductance voltage calculation formula as follows:

[0092]

[0093] Where Vth represents the voltage threshold. The voltage threshold is used to determine whether the terminal is attached in standby state: only when the actual sampled mutual inductance voltage value exceeds the voltage threshold, the wake-up is triggered, so as to avoid false wake-up or missed wake-up caused by weak coupling fluctuations.

[0094] In one embodiment of the present application, the wake-up mobile power supply comprises:

[0095] If the average voltage value is greater than the voltage threshold, it is marked as 1;

[0096] When the number of consecutive marks is 1 for a preset number of times, the mobile power supply is woken up.

[0097] It should be noted that when the average voltage value is greater than the voltage threshold calculated in advance, it indicates that the coil coupling reaches a sufficient fitting state, and there may be a device being attracted and preparing to charge. At this time, the system will mark the current sampling result as 1; if it does not exceed the voltage threshold, it is marked as 0.

[0098] In order to avoid false triggering of wake-up due to external interference or accidental noise, the scheme does not immediately wake up when a single mark is 1, but sets a continuous marking parameter N. Only when the system detects that N consecutive samples are marked as 1, that is, the average voltage value is stable above the threshold in N fixed intervals, it is determined that the terminal is indeed fitted and ready for charging.

[0099] When the number of consecutive 1s accumulates to the preset value N, the controller issues a wake-up instruction, switches the power supply to an upper state and turns on the power stage, and starts wireless fast charging output. Through this multiple continuous confirmation mechanism, not only can the millisecond-level fast response be guaranteed, but also accidental sudden fluctuations can be effectively filtered out, taking into account the detection sensitivity and anti-shake requirements for false wake-up.

[0100] The above describes the embodiments of the present application, but the present application is not limited to the specific embodiments described above, which are only illustrative and not limiting. Those skilled in the art can make many forms under the inspiration of the present application, which are all within the protection scope of the present application.

Claims

1. A standby mode control method based on a magnetic wireless fast charging power bank, characterized in that, The helical coil is divided into an electrically independent and magnetically coupled driving section and an inductive section by a 0.2mm insulation gap, and the following steps are sequentially executed: When the mobile power supply is in a standby state, a wake-up detection is triggered at a fixed time interval, including: injecting a square wave detection pulse into the inductive section, the square wave detection pulse including: an amplitude Ip and a falling edge time tr; Synchronously collecting the mutual inductance voltage value of the driving section timing at a preset sampling period, including: Collecting the mutual inductance voltage value of the driving section on the inductive section at a preset sampling period within the falling edge time of the square wave detection pulse, and the calculation formula of the mutual inductance voltage value is as follows: ； wherein, , represents the rate of change of current of the falling edge of the square wave, Vm represents the mutual inductance voltage value, Rs represents the resistance value of the sampling resistor used to obtain Vm in series with the drive section, k represents the coupling coefficient of the drive section and the sensing section, Lp represents the self-inductance of the drive section, and Ls represents the self-inductance of the sensing section; Calculate the average voltage value of the mutual inductance voltage value, compare the average voltage value with the voltage threshold value, and wake up the mobile power supply. 2.The standby mode control method of a magnetic wireless fast charging mobile power supply based on claim 1, characterized in that, The coupling coefficient of the driving section and the inductive section is obtained as follows: Step 41, using LCR table to measure the self-inductance Lp and Ls of the driving section and the inductive section at 100kHz respectively; Step 42, applying a 100kHz sine wave to the driving section; Step 43, control the inductive section open circuit, measure the inductive voltage SV of the inductive section through the oscilloscope; Step 44, measure the driving section current PI; Step 45, calculate the mutual inductance of the driving section and the inductive section as follows: ； Wherein, M represents the mutual inductance of the driving section and the inductive section, and f is 100kHz; Step 46, calculate the coupling coefficient of the driving section and the inductive section as follows: ； Wherein, k represents the coupling coefficient of the driving section and the inductive section. 3.The standby mode control method of a magnetic wireless fast charging mobile power supply based on claim 2, characterized in that, The average voltage value of the mutual inductance voltage value is calculated, including: Load the sliding time window, the length of the sliding time window is less than the length of the wake-up detection; Based on the sliding time window, the voltage value of the timing is extracted, and the average voltage value of the extracted voltage value is extracted.

4. The standby mode control method of a magnetic wireless fast charging mobile power supply based on claim 3, characterized in that, The voltage threshold value is obtained as follows: Control the mobile power supply to be in an upper state, and repeatedly execute steps 41 to 46 to obtain the peak coupling coefficient of the driving section and the inductive section; Calculate the difference value of the peak coupling coefficient and the coupling coefficient to obtain the sensitive coupling coefficient; In the calculation formula of the mutual inductance voltage value, replace the coupling coefficient with the sensitive coupling coefficient to calculate the voltage threshold value.

5. The standby mode control method of a magnetic wireless fast charging mobile power supply based on claim 4, characterized in that, Wake up the mobile power supply, including: If the average voltage value is greater than the voltage threshold value, mark 1; When the 1 is marked for a preset number of times in succession, the mobile power supply is woken up.

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