Wireless power transfer system with adaptive dynamic safety management

Abstract

Methods and systems for beams for safely and efficiently supplying wireless power from a transmitter to at least one receiver. An incremental signal is generated by repeatedly calculating a power difference between the power of a beam transmitted by the transmitter and the amount of power received at the receiver. The system dynamically generates a time delay that is a period of time shorter than a maximum exposure duration associated with a safe exposure duration for the power level of the incremental signal. If the time delay is exceeded, the system changes an operating parameter of the system, e.g., terminates the beam. Due to limitations in constructing a perfect timing system, the system is constructed to be more sensitive to time delays with longer safe exposure durations, where large incremental signals with shorter safe exposure durations are immediately responded to without much consideration of the time delay.

Description

Technical Field

[0001] This disclosure relates to the field of security systems in wireless power transmission systems, and more specifically, to preventing beam generation damage caused by the transmission of a power beam emitted by a transmitter device. Background Technology

[0002] Numerous wireless power systems have been proposed in this field. However, such systems do not appear to be mature enough to be commercially available, i.e., capable of transmitting sufficient power to operate portable electronic devices, such as smartphones and laptops, within a reasonable distance in an office or home environment, in accordance with safety regulations. These devices require substantial charging power, often exceeding 10W.

[0003] The need for wireless power transmission systems is widely believed to be long-standing, perhaps dating back to the pioneering work of Nikola Tesla in the early 20th century. Some proposed wireless power systems are based on antennas that send electromagnetic beams to photovoltaic cells or receivers, while others are based on sending ultrasonic beams or other types of power beams to receivers.

[0004] The proposed transmitting device, referred to herein as a "transmitter," can use a laser beam or another high-energy beam to power the receiver. The term "receiver" in this disclosure typically refers to an electronic device located remotely from the transmitting device, equipped with photovoltaic cells to convert the beam received by the transmitter into usable energy, enabling the charging of its battery or the power supply of its electronic circuitry without requiring the device to be plugged into a physical outlet. In such a system, the transmitter can identify the receiver by receiving the echo of the transmitted beam from the receiver and / or by receiving wireless communication from the receiver. Typically, a laser beam emitted by the transmitter at a low power setting, or a separate RF or ultrasonic beam, or other means such as a camera, will be used to scan the space where the receiver is expected to be located for charging. Once the transmitter has located the receiver, it can use a scanning mirror to orient its entire beam toward the identified receiver for charging.

[0005] Typically, the beam power transmitted by a transmitter is only permitted to strike a person or other sensitive object or device for a very short period of time or at a very low power setting. This limitation is set by government regulations, such as current U.S. regulations CFR 21–1040 and other similar recognized regulations. In normal use, such a strike to a person or other sensitive object or device will only occur if the power beam is incorrectly directed or if there has been intrusion of the beam by a person or other object. In either case, there will be a difference between the transmitted power and the power received by the receiver. Therefore, such a system must be able to verify that a majority of the power of the beam transmitted by the transmitter is absorbed by the receiver and be able to respond quickly when this situation changes (e.g., if an object is in the path of the beam).

[0006] Some existing technology systems have numerous problems that may imply unacceptable safety hazards in certain situations. Even in systems where the receiver's location is known to the transmitter, the beam can still be absorbed or reflected by objects in the path between the transmitter and receiver, especially if the receiver is located in an optically complex environment (e.g., a home environment). Any portion of the beam "lost" in the path to the receiver can be hazardous because many objects are sensitive to damage from laser beams. For example, if a transparent object (e.g., a window) is located in the path between the transmitter and receiver, it may reflect a portion of the beam passing through it in an unknown direction. This could happen if the transmitter is powering the receiver through a transparent window. The window may not be able to handle such a high power level and could therefore be damaged or even broken. Furthermore, a transparent surface can send some of the beam passing through it onto unintended objects. The transmitter may also misdirect the beam toward flammable objects, increasing the risk of fire-related damage.

[0007] Furthermore, in systems using multiple transmitters, reflected beams may intersect with beams emitted by different transmitters, even in systems designed to prevent direct intersection. This can have unintended and even dangerous consequences, as the power at the intersection point may be greater than safety requirements allow. Additionally, if a beam is misdirected onto an unintended surface, that surface may reflect the beam, causing it to be directed in unwanted directions around space. Alternatively, a surface can split the beam into random directions, potentially exposing sensitive objects or equipment to the beam. Therefore, if a beam is misdirected onto any surface—whether totally reflective, partially reflective, or absorbing (e.g., mirrors, people, animals, cameras, glass surfaces, metal surfaces, and sensitive equipment)—it can create hazardous situations.

[0008] Furthermore, beam profiles typically change with beam propagation, thus beam diameter, optical quality, opposite sides, and other parameters may vary, making it difficult to determine the permissible exposure duration for that power, as permissible exposure may be a function of the beam's power density. Beam profiles and diameters often vary depending on the detection range, and the beam wavelength may change with laser temperature. Therefore, existing systems require comparing power loss over a given duration while taking into account changes in values ​​for each detection range and other laser emission parameters.

[0009] Various system features and methods for achieving secure operation of such optical wireless power transmission systems used with single or multiple receivers are described in international patent applications WO 2017 / 158605 “System for Optical Wireless Power Supply”, WO 2017 / 179051 “System for Optical Wireless Power Supply”, and WO / 2019 / 064305 “Fail-safe Optical Wireless Power Supply” (all of which are jointly owned and co-invented with this application). Other publications have also considered various aspects of the secure operation of such systems. However, the prior art does not directly consider precise methods for combining security procedures with the quantitative requirements of various security regulations, and how to efficiently achieve the system's compliance with them.

[0010] Therefore, there is a need for systems and methods that overcome at least some of the drawbacks of currently available power transmission systems, particularly to achieve efficient and undisturbed power transmission by minimizing the risk of directing laser emission toward sensitive objects or restricted areas without unduly limiting the intended use of the system.

[0011] The disclosure of each of the publications mentioned in this section and other sections of the specification is incorporated herein by reference in its entirety. Summary of the Invention

[0012] A system is disclosed for securely and efficiently supplying wireless power from a transmitter to at least one receiver via a beam. The power difference between the power of the beam transmitted by the transmitter and the amount of power received at the receiver is calculated, assuming that the power is diverted during its journey from transmitter to receiver, thus representing a safety threat to a person, animal, or object in the path of the diverted portion of the beam. The control system is designed to respond accurately to a wide range of power loss signals (indicating a small loss of power during wireless power supply to the receiver) and significant beam loss, indicating an obstacle between the transmitter and receiver equipment. Despite the potentially large power level loss between the transmitter and receiver equipment, the system is suitable for providing reliable protection.

[0013] To calculate the amount of power lost between the transmitter and receiver equipment, the level of power transmitted by the transmitter is typically measured using a power meter, and the level of power received at the receiver equipment is similarly measured using a receiver power measurement or any of the systems or methods described below. A signal representing the difference between these two power levels is calculated, and this signal may subsequently be referred to as the Δ signal or the power loss signal.

[0014] The main problem that must be addressed relates to the regulatory limitations on permissible power exposure in such systems, which is a function of what is considered a safe exposure time. Therefore, only very short exposure times for very high stray power levels are permissible, after which safety mechanisms in the system will terminate the exposure. Conversely, very low exposure levels can be permitted for extended periods, even sufficiently low power levels lasting hours or days, before safety mechanisms in the system terminate the exposure.

[0015] In typical real-world scenarios, even assuming constant power, the Δ signal will not exhibit a constant level because, in addition to the generally stable power delivery from transmitter to receiver, noise interference or transient and non-hazardous beam obstructions can cause the Δ signal to rise and fall. When a system receives these temporary, noise-like changes in the Δ signal, the system can conclude that the change in the Δ signal indicates a situation where the beam emitted by the transmitter is striking a surface other than the receiver unit, thus causing beam-generating damage to any object struck by the beam or to objects in the path of the beam reflected from that non-target surface. Therefore, the correct response should be to terminate the beam or otherwise eliminate the rise in the Δ power reading. On the other hand, if an increase in Δ has already been caused by such noise phenomena, although these changes in power loss may be significant to the system, the Δ signal may return to an acceptable low level within a short period of time, and if this short period of time is less than the permissible exposure time for that power level, the system does not need to terminate laser emission or otherwise modify any transmission parameters to reduce the Δ signal. The guidelines disclosed in this application specify the maximum permissible exposure time as a function of the power loss level between the transmitter and receiver.

[0016] A feature of the currently disclosed systems and methods is the determination of a "wait period" or delay time (hereinafter referred to as T) that is dynamically set according to the level of the Δ signal. delay This wait period is the time it takes for the system to delay its response to the power loss indicated by the Δ signal, in order to avoid premature system shutdown, where this may not be mandatory. delay The delay time must be equal to or less than the maximum permissible duration of power loss measured in the Δ signal, as indicated in the regulations. In addition to the difference indicated by the Δ signal, the delay time can also be a dynamic function of the power transmitted from the transmitter.

[0017] An "event clock," also known as a timing system, is typically used to monitor T. delay This allows the "event clock" to be used as a timer system to ensure that it does not exceed T. delay An "event clock" typically includes an amplification system or a frequency-selective signal processor and typically receives a delta signal as its input signal. Alternatively, the input signal can be the signal output from the receiver power meter, so a large output signal will indicate that at least a large portion of the beam has reached the receiver.

[0018] In this process, the Δ signal changes (whether decreasing or increasing) and therefore T needs to be recalculated. delay In the case of using the new T delay To reset the "Event Clock". The new T delay It can be calculated as the T immediately preceding it. delayThe cumulative differential power over any given period is a function of the power difference calculated over the wireless transmission event, because some objects may remain in the beam path despite other transient changes. A non-limiting example is a case where a partially transparent object is placed in the beam path, and a partially transparent object is then placed separately in the beam path. In this case, the system must calculate a new T. delay This is to match the new power loss between the transmitter and receiver. However, the system may have to account for this new T in the amount of power already accumulated in the first transparent object before the placement of the second transparent object. delay .

[0019] The ambient level of the Δ signal is typically chosen to reflect a clear beam path between the transmitter and receiver, free from significant obstacles that would block and thus prevent a satisfactory portion of the beam from hitting the receiver equipment. If the Δ signal drops to the ambient level, T can be calculated without considering prior power loss. delay This is because it may indicate that there is no significant beam obstruction that might need to be considered for the duration of beam exposure. To illustrate this, if an object is removed from the beam path, causing the Δ signal to drop to ambient level, and the Δ signal remains at or below ambient level for a period of time, the system can conclude that any beam power accumulated on the object is no longer significant because the object has been away from the beam path for a significant amount of time, and therefore a new delay time should begin even if the object is to be reinserted.

[0020] However, if the time it takes for the Δ signal to drop to the ambient level is less than the predetermined or calculated time, T should not be reset. delay This is because it indicates that the object is re-entering the beam path, thus cumulative laser damage may occur. To illustrate this, if an object is inserted into the beam path for a period of time, then removed, and then re-inserted, then T... delay This could be a function of the object's overall exposure to the beam, due to meaningless intervals where the object doesn't exist in the beam's path. Therefore, if the object's total exposure time to the transmitter's beam is not considered, the object may suffer cumulative damage. This relates to the calculation of a new T when the object is re-inserted. delay The situation is the opposite.

[0021] Due to the limitations of a perfectly designed system—that is, a system capable of monitoring slow, weak delta signals while simultaneously responding to very rapid changes in delta signals—the current system is configured such that the frequency range in which the frequency-selective signal processor or amplification system can optimally amplify or monitor is biased to monitor and amplify low-level delta signals, which change only over a long period of time unless an undesirable event causing a sudden jump in the delta signal occurs. Therefore, a long wait period or T... delay The events demonstrate low power loss between the transmitter and receiver, thus requiring monitoring of very slow changes. These events are amplified with higher gain compared to signals occurring at high frequencies, a requirement for high-level Δ signals. This configuration offers significant advantages to the system in efficiently managing security decisions related to spurious beam exposure.

[0022] Furthermore, in another implementation of the currently disclosed system, a saturation level can be selected such that if the incremental signal exhibits a power loss above the saturation level, the event clock can be bypassed. Alternatively, it may be necessary to rapidly modify the timing system to make the event clock substantially uncorrelated, and the control system can terminate laser emission or modify different operating parameters of the system without any delay or the need to calculate a new T for new significant incremental signals. delay This is because incremental signals above saturation levels may be considered potentially dangerous, thus forcing the use of uncorrelated event clock response times, since the maximum exposure duration of these power losses is very short. Therefore, the calculated T... delay The frequencies are so short as to be negligible, making them difficult to distinguish from one another. Therefore, the frequency response of an amplification system associated with an event clock can be configured to shift its passband to a lower frequency, thus providing meaningful amplification at lower signal frequencies, since a response to frequencies associated with power above saturation levels is required, while the timing of the event clock is essentially not required. This adjustment to the normal expected frequency response of the amplifier or processor allows the system to cover the required large dynamic range.

[0023] Calculations can be performed using digital electronic devices, analog electronic devices, or even other physical processes. Analog amplifiers can perform integration, summation, windowed summation, and expression of delays. Other components (e.g., capacitors, inductors, and other electronic components) can also be used to perform some or all of the calculations, in conjunction with digital electronic devices, or even without digital electronic devices.

[0024] Each Δ signal has T delayThe setting reflects its allowed exposure time. If Δ changes, the event clock or amplification system needs to be reset to a new wait time so that it continuously adjusts to the maximum allowed wait time for the power loss currently indicated by the Δ signal before the power beam must be truncated. The event clock or timer may not have a sufficiently fast response time for signals that change very rapidly, so a rapid but potentially significant change in the signal may appear late in the amplifier's output signal and therefore not be able to reset the clock quickly enough. However, if the Δ signal increases significantly, although the system cannot meaningfully maintain the allowed short delay time—meaning a lack of ability to amplify signals that force such a high frequency response—the high power level of the Δ signal is sufficient for the controller to respond, even though the amplification is low at those high frequencies, thus enabling the controller to respond quickly enough to trigger a safe shutdown before the allowed exposure time has been reached.

[0025] Another feature of the system described herein concerns the method for handling foreign noise or anomalies in the signal. To ignore such foreign noise or anomalies in the signal (e.g., changes that occur so rapidly that the system identifies them as noise) and without needing to respond to them, the system can generate an average of the signal received over a variable time period, rather than having to decide whether to respond in real time. The averaging calculation can be used to determine whether the change in the signal is so transient as to be negligible, or whether the Δ signal has indeed changed significantly and therefore requires resetting the event clock to reflect the new T forced by the new Δ signal. delay This allows changes that occur in a very short period of time to be ignored.

[0026] It should be understood that a significant change in the Δ signal can be a dynamic value proportional to the Δ signal itself. This means that if a large portion of the power is lost, a small change in the Δ signal may not require the calculation of a new time period, as opposed to cases where the Δ signal indicates a very small power loss, in which case a small change may be more significant, causing the event clock or frequency selection processor to generate a new time period.

[0027] According to the substitution process, a predetermined value of Δ can be used such that if the Δ signal changes the predetermined value, a new time period is always generated.

[0028] Therefore, T delay Calculations were performed dynamically with a high repetition rate, taking into account real-time changes in the incremental signal. T at any given time point... delay The value is a function of the incremental signal values ​​measured at different recent time points. For example, T at time T. delay It is usually a function of the incremental signal at time T, and then at time T nContinuous monitoring is conducted to ensure the security of transmission in the most efficient manner.

[0029] The timer or amplification system must be configured to meaningfully track signals with low amplitudes because the timer's wait or delay time should be long enough for the amplification system or timer to meaningfully track and respond. This delay time or wait period is necessary to allow the system to ignore false alarms from noise spikes and thus to allow the system to avoid continuously and erroneously turning the laser on and off.

[0030] On the other hand, if a large Δ is indicated, the permissible exposure time for such a large power loss is very short. Therefore, if a large number of uninterpreted beams are indicated, the system may have to react very quickly according to regulations. The system must reset timers or event clocks to the maximum permissible duration for such a large power loss, and there may be a very short period before reaching and passing the delay time. Therefore, the system must determine very quickly whether the large Δ is due to a brief anomaly in the noise or a butterfly flying across the beam path, or whether there is indeed a dangerous intrusion into the beam path.

[0031] It is difficult to build a hazard prevention system that offers a sufficiently fast response to a large dynamic range of signals while also possessing such a large operating bandwidth. On one hand, the required signal dynamic range is extremely large because the system must continuously monitor very low-power signals without being saturated by very high-power signals. In addition to this large dynamic range, the system must also have a large response bandwidth to maintain its ability to monitor very low-level signals over long periods while retaining its rapid response capability when high-level signals appear. When low-level signals are detected, such a system becomes sensitive to noise and is limited by bandwidth and phase delay when a fast response is required.

[0032] Based on an implementation of an exemplary system that satisfies the above requirements described in this disclosure, a hazard prevention system is described, comprising: a power meter in a transmitter for measuring the laser output power of the transmitter; a power meter in a receiver for measuring the input laser power to the receiver; and a control unit for receiving two signals from both the power meter and a power reduction switch, wherein the control unit typically shuts off or redirects the beam to prevent hazard if the difference between the power transmitted from the transmitter and the power received by the receiver exceeds a threshold.

[0033] This hazard prevention system may have the following properties:

[0034] The system is configured to overestimate the power transmitted by the transmitter, at least in most cases, thereby ensuring that errors and noise are explained by supporting safe methods.

[0035] The system is configured to underestimate the power received by the receiver, at least in most cases, thereby ensuring that errors and noise are explained by supporting safe methods.

[0036] The system has a transfer function relating the occurrence of the actual difference between the power emitted from the transmitter and the power received by the receiver to the actual response of the laser system (typically by reducing the power), wherein the transfer function is configured such that it does not have the characteristic of "instantaneous response". For example, if the difference between the measured power emitted from the transmitter and the measured power received by the receiver is small compared to an allowable level, this delays the response, thereby reducing the effect of noise.

[0037] When expressed in terms of laser power or gain, the transfer function in phase delay space has the following properties:

[0038] When the difference signal exceeds a predetermined threshold, it has a negative gain because the laser power decreases in response to the system power loss exceeding the threshold.

[0039] It has a delay in response to a differential signal of a specific value, which is calculated using the expression given below:

[0040]

[0041] Among them, P transmitter It is the power of the laser emitted by the transmitter, measured in watts.

[0042] Among them, P receiuer It is the laser power received by the receiver, measured in watts.

[0043] Among them, P transmitter -P receiver It is the power difference used to generate the incremental signal mentioned above.

[0044] Where λ is the laser wavelength, measured in nanometers, and

[0045] Where, τ delay It is for P transmitter With P receiver Given the difference, the time delay, measured in seconds, between the occurrence of a hazard and the time it takes for the system to reach a safe state.

[0046] It has a saturation level, for P transmitter and P receiver Defined as in P transmitter With P receiver The difference in level between them, at which a level increase of 1 dB or more results in a P transmitter The decrease versus the absence of such an increase in Ptransmitter The decline is essentially the same.

[0047] The saturation level is defined as a power loss level above a certain predetermined power loss, for example, 10mW for a typical home charging environment. At this exemplary saturation level, according to the T specified above... delay The response time will be less than approximately 5 μsec, which is slightly greater than the maximum permissible exposure duration of 10 mW, and a 5 μsec response time corresponds to a frequency response of 200 kHz. Therefore, according to the last criterion mentioned above, this means that if the system indicates a power loss higher than this saturation level, then T... delay The values ​​of saturation are negligible, so the response times at these high power loss points will be indistinguishable from each other and must be executed at the same high speed. Therefore, if the saturation level is chosen to be high, the response to all events requiring faster response times will be the same. This makes it possible to use systems with their bandpasses at lower frequency locations that still respond to high-frequency signals. Thus, a large signal dynamic range is considered while maintaining a large effective bandwidth.

[0048] The system's response to incremental signals requiring fast response times (above the selected saturation level) typically does not involve any delay mechanism (also known as an event clock). This eliminates the need to distinguish between such high-amplitude incremental signals that may be prone to noise.

[0049] Minimum delay time has two advantages: it allows the system to use the delay to reduce the effects of noise and prevents the transmitted power from being reduced due to errors, while at the same time keeping the system safe.

[0050] Therefore, according to an exemplary embodiment of the device described in this disclosure, a system for providing wireless power to at least one receiver is provided, the system comprising:

[0051] (a) A transmitter adapted to transmit a beam of wireless power;

[0052] (b) A power meter configured to generate a first signal corresponding to the power level of the transmitted beam;

[0053] (c) A detector associated with at least one receiver and configured to generate a second signal corresponding to the power of a beam received at the receiver;

[0054] (d) At least one controller adapted to perform the following operations:

[0055] (i) Generation time period T delay During this time period T delay Less than the maximum safe exposure duration for the difference in power measured by the power meter and detector;

[0056] (ii) If the power difference has changed by more than a significant amount, then dynamically generate a new T. delay ;as well as

[0057] (iii) If it exceeds T delay If so, at least one operating parameter of the transmitter is modified to reduce the power difference.

[0058] Such a system may include a frequency-selective signal processor, which is used to generate T delay The signal previously processed corresponds to a power difference. In either such case, if the difference exceeds a predetermined power level, the controller can be configured to respond without waiting beyond T before modifying the transmitter's operating parameters to reduce the incremental signal. delay Alternatively, the frequency selection processor can be configured such that its passband is set to cover frequencies significantly below a range required to respond within the time period mandated by the maximum level of the expected differential signal.

[0059] Furthermore, according to another implementation, the frequency selection processor can be configured such that its frequency response curve is shifted to frequencies lower than those indicated by the center of a frequency range required to provide amplification over the expected exposure duration range according to the power delivery system. In this case, the shift in the frequency response curve can provide increased amplification to low-level power difference signals, allowing the processor to respond to changes in these low-level signals. Additionally, the shift in the frequency response curve can provide increased amplification to low-level power difference signals, enabling these signals to generate a processor output sufficiently high above the noise level to trigger laser safety routines.

[0060] In any of the above systems, the controller can also be configured to... delay The calculation is a function of the previously generated difference signal. In this case, a difference signal below a predetermined ambient level can indicate that there is no significant beam obstruction between at least one transmitter and at least one receiver. If so, then if the difference signal drops below the ambient level within a predetermined time period, then T... delay The generation is not significantly based on any prior differential signals.

[0061] Additionally, when the controller is configured to... delay In any of the systems that compute T as a function of the previously generated difference signal, the system can be configured to respond to any difference signal above the ambient level by: calculating T for a signal below a predetermined level but above the ambient level. delay Or, if the difference signal is higher than a predetermined level, then it is related to T.delay The system responds unrelatedly. Alternatively, it can be configured to respond to any differential signal above ambient level by calculating T for signals below a predetermined level but above ambient level. delay Alternatively, the transmitter's operating parameters can be modified to reduce incremental signals.

[0062] In any of the above systems, the frequency selection processor may include an amplifier. Furthermore, in any of such systems, if the time elapsed from step (i) exceeds T... delay Then step (iii) can be performed.

[0063] Furthermore, in other embodiments of the above system, modifying at least one operating parameter of the transmitter may include at least one of the following:

[0064] Modify the beam power level;

[0065] Completely terminate laser emission;

[0066] Change the beam profile of the emitted beam;

[0067] Blocking beams;

[0068] The beam can be directed to different locations by using a scanning mirror;

[0069] Scan the area around the current scan position to better align the beam to the receiver; and

[0070] Record the scan position of the marked object in the beam path.

[0071] According to another exemplary implementation of the device described in this invention, a method for providing secure wireless power to at least one receiver is also provided, the method comprising:

[0072] (a) Transmitting power from at least one transmitter to at least one receiver;

[0073] (b) Generate a first signal corresponding to the level of the power transmitted by at least one transmitter;

[0074] (c) Generate a second signal corresponding to the level of power received at at least one receiver;

[0075] (d) Generate a difference signal, which is the difference between the second signal and the first signal;

[0076] (e) Generation time period T delay During this time period T delay Less than the maximum exposure duration associated with the safe exposure duration of the power indicated by the difference signal;

[0077] (f) Monitor whether the difference signal has changed by the predetermined amount, and if the difference signal has changed by the predetermined amount, return to step (e); and

[0078] (g) If it exceeds T delay Then, at least one operating parameter of the wireless power supply is modified in order to reduce differential signals.

[0079] In this method, the system can respond to difference signals above a predetermined level without using T. delay This determines the time period to wait before modifying at least one operating parameter of the wireless power supply. Alternatively, T can be calculated by averaging the difference signals over the time period. delay This results in a difference signal indicating a high power level having a shorter average time compared to a difference signal indicating a lower power level, the amount of which depends on the power level indicated by the difference signal.

[0080] In another implementation of the system disclosed herein, a system for transmitting laser power from a transmitter to at least one receiver is described, the system including a hazard prevention system comprising:

[0081] A power monitor that measures the optical power of a laser emitted from a transmitter; and

[0082] A power sensor used to measure the optical power of a laser at at least one receiver;

[0083] The hazard prevention system is configured to reduce or terminate the laser power in response to an increase in the difference between the measurements of the power monitor and the power sensor, after a time delay following the occurrence of the increased difference. This time delay, measured in seconds, is:

[0084]

[0085] Among them, P transmitter The laser power is measured by a power monitor, in watts.

[0086] Among them, P receiver The laser power is measured at a power sensor, in watts; and

[0087] Where λ is the laser wavelength, which is measured in nanometers.

[0088] Another exemplary system describes a system for securely supplying wireless power to at least one receiver, the system comprising:

[0089] (a) A transmitter adapted to transmit a beam;

[0090] (b) A power meter used to measure the power level of the emitted beam;

[0091] (c) A detector associated with a receiver and configured to detect at least a portion of a beam received at the receiver; and

[0092] (d) A frequency-selective signal processor, which is adapted as follows:

[0093] (i) Generate a representation of time period T delay The output signal during the time period T delay Less than the maximum exposure duration associated with the safe exposure duration for the difference in power measured by the power meter and detector; and

[0094] (ii) Monitor self-generated T delay The time elapsed since then, and if it exceeds T delay If so, at least one operating parameter of the transmitter should be modified to reduce the difference;

[0095] The frequency selection processor is configured such that if the output signal is higher than a first predetermined level, the frequency selection processor has such a response characteristic that it modifies the operating parameters of the system without making significant changes.

[0096] In such a system, the frequency selection processor may have a frequency response biased to a low frequency, such that the difference signal is amplified more than a signal above a first predetermined level, the difference signal having a level less than a second predetermined level and associated with an exposure duration that is significantly longer than the permissible exposure duration level for power exposure above the first predetermined level.

[0097] Finally, according to yet another embodiment of these systems, a system for securely supplying wireless power to at least one receiver is provided, the system comprising:

[0098] (a) A transmitter adapted to transmit a beam of wireless power;

[0099] (b) A power meter configured to generate a first signal corresponding to the power level of the transmitted beam;

[0100] (c) A detector associated with at least one receiver and configured to generate a second signal corresponding to the power of a beam received at the receiver;

[0101] (d) At least one controller adapted to perform the following operations:

[0102] (i) Determine the allowable cumulative energy exposure limit for a power level that is related to the difference in power measured by a power meter and a detector;

[0103] (ii) If the difference has changed by more than a significant amount, then a new energy limit is dynamically generated; and

[0104] (iii) If the energy limit is exceeded, at least one operating parameter of the transmitter is modified to reduce the difference. Attached Figure Description

[0105] The invention will be more fully understood and appreciated from the following detailed embodiments, taken in conjunction with the accompanying drawings, in which:

[0106] Figure 1 A typical example of a wireless power supply system according to this application is shown;

[0107] Figure 2 A specific specification is shown for the permissible exposure duration at different laser beam power levels;

[0108] Figure 3 illustrates existing amplifiers, processors, or control systems. Figure 2 A schematic diagram of the response curves across the entire frequency range is shown.

[0109] Figure 4 A schematic diagram of the response curves of an amplifier, processor, or control system is shown, which is configured such that its frequency response curve is shifted to frequencies lower than those shown in the curves of Figure 3.

[0110] Figure 5A This is an example diagram of the differential power signal obtained in a typical detection scenario as a function of time. Figure 5B It shows the result of Figure 5A The control signal generated by the power profile shown in the figure; and Figure 5C This illustrates the case where the system ignores the short noise spike "A";

[0111] Figure 6A and Figure 6B Various scenarios are shown where truncating or redirecting laser transmission may become necessary to avoid dangerous situations that could cause potential laser damage.

[0112] Figure 7 This is a flowchart illustrating one implementation of a method used in operating the currently disclosed system; and Figure 8A and Figure 8B The permissible exposure time for different power levels is shown in accordance with U.S. regulations. Detailed Implementation

[0113] Now for reference Figure 1 , Figure 1 A typical setup for a wireless power supply system is illustrated. A transmitter 10 is shown, which includes a beam generator 12 (e.g., a laser) to direct a beam 17 toward a receiver 15. To measure the power level of the laser beam emitted by the transmitter, the system includes a first power meter 13, referred to as a transmit power meter. The transmit power meter 13 may be located inside the transmitter 10 or in the beam path at the transmitter exit. This power meter can sample the emitted beam at a high sampling rate (e.g., at a frequency of 5 kHz or higher), allowing the system to obtain changes in the power of the emitted beam in real time without delay.

[0114] Typically, receiver 15 includes a photovoltaic cell 16 that converts the light energy of the beam into usable electrical energy, usually used to charge or power devices associated with the receiver. If a portion of the beam is directed onto a surface other than the receiver's power absorption aperture, stray beams can cause dangerous laser-generated damage. If the beam is incorrectly directed onto any surface—whether totally reflective, partially reflective, or absorptive (e.g., mirrors, people, animals, cameras, glass surfaces, metal surfaces, and sensitive devices)—these surfaces can create hazardous situations.

[0115] Therefore, a second power meter 14 (i.e., a receiver power meter) associated with the receiver can be used to measure whether the receiver is receiving all or at least a large portion of the beams directed toward it, allowing the system to determine whether a significant portion or even any part of the beam is being directed elsewhere, potentially leading to dangerous consequences. The receiver power meter 14 can receive a portion of the beam from a beam splitter (not shown) located in the receiver, or in other cases, an ammeter, voltmeter, or photovoltaic cell itself can be used as a power meter in the receiver. The portion of the beam received by the receiver power meter is proportional to the power of the beam striking the receiver.

[0116] The system also includes a controller 18. The controller 18 receives a signal 14 from the receiver power meter 14, representing the amount of power detected at the receiver. sig The controller also receives a signal 13 from the transmit power meter 13 indicating the amount of power of the laser beam 17 leaving the transmitter 10. sig .

[0117] The controller 18 will receive the beam signal 14 detected by the detector 14. sig With signal 13 representing the amount of power emitted by laser 12 sigThe measurements are compared. If the difference between these measured powers is significant, the system can generate an indication of a hazardous situation because a large amount of power emitted by the transmitter is not considered by the receiver equipment and may therefore impact surfaces other than the receiver equipment, potentially causing damage. Therefore, the system continuously performs checks to determine the level of unconsidered power. The controller is configured to respond if the level exceeds a predetermined threshold to reduce or eliminate this unconsidered beam power by causing at least one of the following:

[0118] Modify the beam power level;

[0119] Completely terminate laser emission;

[0120] Change the beam profile of the emitted beam;

[0121] Blocking beams;

[0122] Typically, beams are directed to different locations by using scanning mirrors, such as beam collectors;

[0123] The system directly scans the area around the current scan position to attempt to better align the beam to the receiver, and if the scan finds a location where the difference signal drops, it instructs the transmitter to use a better scan direction.

[0124] The scan position that records the location of the marked object in the beam path; and

[0125] Change any other operating parameters of the system.

[0126] During laser emission, the reduced power level striking the receiver is typically associated with an object crossing the beam path. Therefore, the controller should be able to modify the laser output based on the power level indicated as a loss between the transmitter and receiver to protect any such object that has entered the beam path. Power sampling at both the transmitter and receiver should be performed at a sufficiently high sampling rate to ensure that indications of partial changes in the received beam are obtained quickly enough to comply with safety regulations mandating such protection. The impact of the sampling rate on the system's ability to respond correctly in time—whether to low leakage power occurring over long periods or to high leakage power that must be rapidly truncated and therefore requires a fast time response from the system—will be explained below.

[0127] Now for reference Figure 2 , Figure 2This illustrates a specific specification for the permissible exposure duration at different laser beam power levels. The specific graph shown gives the maximum permissible exposure level in dBm for exposure to illumination with a wavelength of 1050 nm and a beam diameter of 7 mm with a Gaussian profile. The horizontal axis shows the bandwidth in Hz required by the amplifier or processor to successfully process the response time implied by the maximum permissible exposure time at the plotted exposure level.

[0128] Figure 1 The system shown must ensure that those portions of the beam that are not considered and therefore may strike a person or other objects in the field of vision (i.e., the difference between the signal received at the detector and the amount of power emitted by the transmitter) do not exceed the guidelines for the maximum permissible exposure duration allowed by various national regulations. Figure 2 The curves in the figure are obtained from US Code of Federal Regulations Title 21, Volume 8 [CITE: 21CFR1040.10], as amended April 1, 2018. The figure shows the permissible exposure time (expressed as the effective response frequency of the measurement system) for a 7mm Gaussian beam with a wavelength of 1050nm as a function of the power level (in dBm) to which the object is exposed.

[0129] As the beam power level increases, the permissible exposure time decreases. Therefore, if the controller indicates that a large portion of the high-power beam's power is not being taken into account, it is necessary to modify the system parameters very quickly. Alternatively, if the controller indicates that only a small portion of the beam power is lost, a longer period of time is allowed before the controller must instruct the laser to adjust or redirect the beam. Figure 2 As shown. Therefore, for example, regarding its permissible exposure level as Figure 2 For the 7mm beam shown, at a power level of 0dBm (1mW), the permissible exposure time, according to the aforementioned reference specifications, is on the order of 10 seconds. Therefore, the bandwidth of the control loop responding within these 10 seconds must be extended to at least 0.1Hz. Similarly, for the same beam but with a power of 10dBm, the permissible exposure time is on the order of 5ms. Therefore, the bandwidth of the control loop responding within this time must be extended to at least 200Hz.

[0130] To provide further non-limiting examples of these protection levels in accordance with the aforementioned reference regulations, and to illustrate how the required protection level depends on several parameters of the beam, if a system using a circular beam with a diameter of 10 mm and a uniform beam profile (which is the preferred beam profile for converting photovoltaic cells into electrical energy) and a wavelength of 1050 nm is shown to have a power of 6.8 milliwatts not taken into account, then the beam needs to be terminated within a 1-second time period.

[0131] On the other hand, if the beam profile is Gaussian, and the system only shows a loss of 5.35 milliwatts of beam power, the laser beam needs to be terminated or modified within 1 second.

[0132] Similarly, if a similar system using a 7mm diameter Gaussian beam indicates that only a 3.3mW beam is not being considered, then that beam needs to be terminated within 1 second.

[0133] If the beam wavelength changes from 1050 nm to 1060 nm (possibly due to a change in laser temperature), then in a system where the 5.6 mW power is not considered, the permissible exposure duration for a 10 mm Gaussian beam is 1 second.

[0134] It should be noted that the term "safe exposure time" used in this disclosure for exposure to a specific beam power is understood to refer to any period of time during which the beam power is less than the maximum permissible exposure time allowed by the regulations in effect at the time of use. As in Figure 2 As observed in the entire context of the figure, the permissible exposure duration can vary from nanoseconds to tens of hours, depending on the power level lost by the laser beam during transmission, and the power level to be monitored ranges from a few microwatts to orders of magnitude 10 watts.

[0135] Therefore, a signal processing system capable of handling the required response to a signal representing a loss of 10W of power must have a dynamic range typically exceeding 60dB and a frequency response extending to approximately 10MHz, corresponding to a response time on the order of 0.1 microseconds. Such a large signal dynamic range and bandwidth covering such high frequencies are practically impossible to achieve with currently available electronics, whether analog or digital. Therefore, one object of the present invention is to provide a system that is sensitive to all power levels within such a large power dynamic range and has the ability to react within the most efficient time given by regulatory requirements for measuring the desired maximum power (i.e., as fast as approximately 100 nanoseconds for the aforementioned 10W power range).

[0136] Referring now to Figure 3, Figure 3 illustrates a prior art amplifier, processor, or control system in Figure 2The diagram shows a schematic of the response curves across the entire frequency range. Because the range is very large, the axes are plotted logarithmically. In the selected example, peak amplification extends around a frequency centered at 10 Hz and is shown as having a significantly useful response, thus covering two decimal places or slightly more, both above and below that frequency. This response range is not intended to be limiting, but merely illustrates a typical range illustrating the problem that current methods and systems attempt to address. As indicated in Figure 3, the typical time exposure range corresponding to the response frequencies where significant amplification exists ranges from approximately several hundred microseconds to several tens of seconds. Amplifying outside this range, or amplifying at the low end of the spectrum, may have too little ability to distinguish between real signals and signal-to-noise levels to provide appropriate warnings that would trigger the system's safety features if permissible power is exceeded. In practice, the response speed of an amplifier system is achieved not only by the electronic response characteristics of the amplification and control circuitry, but also by the sampling rate at which the system samples the measured power to determine if a threshold has been reached.

[0137] It should be emphasized that the frequency range discussed in this example may be typical levels for everyday household situations, but this does not mean that it is a limitation for every situation.

[0138] Now let's return to the uncertain beam power exposure level, which is associated with the maximum permissible exposure time defined by safety regulations, for example, such as... Figure 2 As shown, the power range allowed for the aforementioned exemplary exposure time ranges from hundreds of microwatts to tens of milliwatts for a typical beam size. Therefore, power falling outside this range may not be adequately amplified by the system, and thus, if the power threshold of an indeterminately oriented beam is exceeded for longer than the allowed time, the system cannot generate the correct instructions to reduce or redirect the beam. There are two entirely different scenarios regarding this lack of responsiveness.

[0139] At the high-power end of the response curve, only very short exposures are permitted, and if this power is exceeded, the amplification system must respond very quickly to shut down or redirect the beam. This means that despite the very low amplification, the inadequacy is not solely compensated for by the signal amplitude input to the amplifier, but is caused by the very high power level. Therefore, although the amplification level at those high frequencies is significantly insufficient, the high signal level compensates for this low amplification, providing a sufficient output signal to trigger safety conditioning steps to reduce radiation. However, at the low-power end of the response curve, prolonged exposure is permissible—operating for hours or even days at the lowest regulated power—without such compensation. Thus, the power level itself can compensate for the shortcomings of amplification at such low frequencies, such as the amplification system's inability to distinguish between signal and noise levels. Furthermore, although the power levels involved may seem negligible, there is still a maximum permitted time period for human exposure to such low power, and the transmitter's safety system must be able to ensure proper compliance with this standard. Additionally, at these low power levels, the system must always be able to respond quickly to significant increases in leakage power, which must trigger safety actions within the permitted exposure time.

[0140] To achieve this objective, according to the first implementation of the system disclosed herein, such as Figure 4 As shown, the amplifier is configured such that its frequency response curve is shifted to frequencies lower than those indicated by the center of the frequency range that the amplifier should handle. Due to this shift to lower frequencies, very small signals generated at the power meter by low power levels associated with long permissible exposure periods experience a higher amplification level than the noise level compared to amplifier selection criteria using existing technology. Therefore, compensation is provided for this low signal level so that they can produce a sufficiently high output above the noise level to trigger laser safety routines. Thus, in Figure 4 It is clear that by shifting the center of the frequency response to 0.1 Hz instead of 10 Hz, the amplification in the extremely low frequency range is significantly increased, thereby providing sufficient output signal for those low-power spurious beams to enable beam safety systems.

[0141] On the other hand, as previously explained, at the high-power end of the beam power spectrum, the amplifier frequency response curve shifts to a lower frequency, thereby further reducing the low amplification provided at that end of the spectrum. This has a smaller impact on the efficiency of the safety warning system because the signal generated by the high spurious beam power is so large that even if the amplifier sensitivity is reduced in this high-frequency range, it will still generate enough output to operate the safety system.

[0142] However, a functional challenge remains: how to achieve this increased sensitivity at low power while ensuring the system responds quickly enough to high power. Regardless of whether the detected power is low or high, a rapid response to significant increases in detected power is still necessary. Response time is expressed as the sampling rate the system uses to measure power. The shorter the required power measurement response time, the higher the sampling rate the system must use to measure that power. Therefore, even when detecting very low power, the system must maintain a fast response time to power increases to the system's desired maximum value. The sampling rate can typically be chosen to be three times or more the maximum permissible exposure duration for a power difference signal that shows full beam obstruction. A system using this sampling rate will allow monitoring for sudden spikes in the power difference signal against at least one sample before requiring modification of laser emission, thus allowing for a short, albeit brief, averaging calculation before acquiring the response, where the signal may drop to an acceptable low level.

[0143] On the other hand, the sampling rate can be chosen to be substantially the same, but never less than a value equal to the maximum permissible exposure duration for a completely lost beam. Within this time constraint, the sampling rate can even be chosen to be two or fewer samples.

[0144] However, as previously mentioned, fast response time and high sampling rate increase sensitivity to noise. As mentioned above, increasing amplifier sensitivity at low power amplifies this effect.

[0145] To achieve these objectives, efficient variable sampling rates can be used in the systems disclosed herein. Response time is expressed in terms of the sampling rate used by the system to measure power. The shorter the required power measurement response time, i.e., the higher the uncertain power level to be detected, the higher the sampling rate the system must use to measure that power. Therefore, to ensure that the highest power that the system can transmit is responded to within the allowable time limit for that power level, the sampling rate must be kept at a high rate, typically several times faster than the rate at which the time between samples will be the maximum allowable safe time for the maximum system power. However, as already mentioned, a fast sampling rate can lead to excessive sensitivity to noise, and at low transmit power, the signal generated by the detected power may be difficult to extract from the noise level, potentially leading to premature activation of the threshold shut-off or beam steering procedure.

[0146] To overcome this problem, the control can be designed so that for low-level measured power signals, the sampling rate can be reduced, and the power signal is less urgent to respond to. However, the sampling rate must still be maintained above the sampling rate required to respond within the maximum time allowed for the expected maximum exposure. When the system power itself is low, the sampling rate may be less frequent because the maximum allowable exposure time for that beam is long, and therefore there is no need to respond to changes in the power signal within such a short time.

[0147] The controller can be advantageously configured such that there may be a time delay between receiving an indication of power loss and the controller actually acting on the received signal level and modifying the system. This time delay allows the system to determine whether the detected signal is truly due to a continuous power loss throughout the entire sampling period (this indicates a real instance where power may have been diverted somewhere along its transmission path), or whether it is the result of excessive noise detected at those low signal levels. This is achieved by averaging the power signal up to the end of the time delay and using the averaged signal to determine whether a threshold has been reached and whether the laser should be terminated or diverted, or whether the signal is merely the result of noise pickup or transient events, and can be ignored when determining whether the true safe threshold time has been reached. The time delay is a function of the maximum permissible duration of the power loss detected at the power signal. The time delay must be slightly less than the maximum permissible duration for that power loss.

[0148] The beneficial results of this procedure are now in Figure 5A , Figure 5B and Figure 5C It is displayed in the middle. Figure 5A This is an example diagram of the differential power signal as a function of time, obtained in a typical detection scenario; that is, the power level of the beam power lost during transmission. The symbol Δ represents the differential power measured by the difference between the transmitted power and the actual power incident on the receiver. Δ is plotted as a function of time t. The average or ambient power level Δ1 shown in the areas labeled A, C, and E in the diagram is so low that the permissible exposure time to this leakage power level is long, and extends beyond [a certain time] unless other events involving larger differential power levels occur. Figure 5A The total time is shown in the figure. The sampling rate is maintained at a sufficiently high rate to match the need to respond to a sudden increase in Δ of the system's maximum transmitted power, such that this increase in power will result in the system maintaining appropriate safety protection.

[0149] However, in the case marked T 1sAt a certain point in time, an event occurred that could be a partial absorption object briefly intruding into the path of the transmitted beam, causing Δ to rise to level Δ2. According to the mandatory rules for beams with an average power of Δ2, this level extends to point T. 1r The maximum permissible exposure time, therefore T 1r With T 1S The difference is the time allowed for exposure level Δ2. According to the system described herein, for such a moderate detection power difference represented by Δ2, the decision regarding whether the increase in Δ indicates a significant change requiring a response from the system is delayed by the controller, thus adapting the system to wait a delay before terminating the beam to determine whether the signal change is significant or an actual rise in signal strength, or whether the spike is caused by noise or transient anomalous readings in the system. The delay is determined by the power loss level displayed by the system, which, in the case of a moderate power level Δ2, extends to T. 1d This makes T 1s With T 1d The time difference between them allows the system to reach the allowable exposure time T. 1r The previous delay was to determine whether the change in signal to Δ2 required a response. In fact, it can be seen that the signal transition to Δ2 (marked by time period "B") does not require modification of the system's operating parameters (e.g., beam termination), because by the time T... 1d Previously, the beam obstacle that caused the jump to power level Δ2 had passed, and the detected power dropped back to its low level, approximately Δ1, at time T2. Because this method... 1s To T 1d The signal is averaged over the entire time period C, so the control system does not prematurely activate the system trigger to remove the laser emission, just as it would be done without using this time delay standard, and the charging service does not terminate prematurely.

[0150] In a similar manner, at time T 3s The system suddenly detects a large spike in power loss, with a significantly increased detected power level Δ3. Using existing control systems, such a power pulse would be detected rapidly and the laser emission would be immediately shut down (as an example of the action to be taken), because the high level indicates a large amount of beam loss that may be hitting a dangerous target. This would be done in existing systems that do not consider pulse length. Using the control system of this disclosure, the threshold decision is delayed beyond the sampling time T. 3d This is to properly assess the danger level presented by the increased power. Note the T value in region D for this spike. delay Shorter than T for power increase in region B delayBecause of the high power level, the permissible exposure time is short. By using this delayed decision response time, sharp power spikes are averaged out within their temporal context, allowing for a period of time to determine whether the overall average level of the signal is below the level that forces the system to shut down.

[0151] Figure 5B Now shown is the work by Figure 5A The power profile shown generates the resulting control signal. The medium-level event shown in time period "B" and the larger jump to Δ3 during time period "D" are both processed by the system to be averaged before being input to the control system. Now, neither of these events triggers a safety threshold, allowing the system of this disclosure to continue providing charging service without interruption, whereas in previous systems, the threshold criterion would be triggered immediately upon occurrence of the first sampling period, and the system would shut down.

[0152] Figure 5C The example shows a case where the short spike "A" is ignored by the system because the sampling of the signal and its subsequent averaging make it possible to determine that no significant change has occurred due to the signal rapidly dropping to a low level.

[0153] However, when the spike "B" is amplified, the system can determine that this increased Δ signal is rapidly exceeding the permissible duration for this unconsidered beam power level. Subsequently, the system terminates laser emission, so no power is received at the receiver, and the Δ signal drops to zero, as shown at the end of time period "B".

[0154] Now for reference Figure 6A and Figure 6B This illustrates various scenarios where truncating or redirecting laser transmission may become necessary to avoid potential laser damage.

[0155] Figure 6A An exemplary scenario is shown in which a person 60 crosses beam 67. In this case, the signal received by the receiver power meter will be at its normal high level before the person enters the beam path, so the power loss Δ calculated by the controller, or between transmitter 61A and receiver 65A, will be very low. Therefore, transmitter 61A can direct the full-power beam to the receiver before the person enters the beam.

[0156] When person 60 then enters beam path 67, the power level received by the detector will drop sharply, resulting in a high difference Δ between the power detected leaving transmitter 61A and the power detected at receiver 65A. This means that the high power level is dissipated somewhere in the transmission space without reaching the receiver, potentially leading to high-level exposure to the beam. Such high power exposure must, by design, result in spurious beam reduction within a very short time. Due to the large change in power level and the short response time required by the system amplifier, the system amplifier may not faithfully process the corresponding signal change and issue a shutdown or beam-switching command within the required time. However, despite the lack of meaningful amplification at such high frequencies, the Δ signal will be high enough to ensure that the system responds within a small, permissible time for this power loss.

[0157] Figure 6B The case where a transparent object 64 or an object that only partially blocks the beam path is now shown. Since the detected change in power may be small, such stray beam power is acceptable over a relatively long period of time according to regulations.

[0158] The duration of this event can be very long, as an object could remain in the beam path for minutes or even hundreds of minutes for a low-level, uncertain power exposure, allowing laser emission to continue uninterrupted. Existing systems are insensitive to such small power losses between transmitter and receiver over such long periods because the effective frequency of such power changes is too low for them to detect. However, even if Δ, representing the unconsidered portion of the beam, is very small, the permissible exposure time can be very long, potentially exceeding the maximum permissible time level if power transfer from transmitter to receiver occurs within this extended period.

[0159] In the currently disclosed system, the frequency amplification, which is associated with very slow changes in the input signal and occurs over long periods, is increased compared to existing systems, making it more sensitive to events occurring over long periods. Therefore, the combination of these characteristics enables the system to respond correctly over long periods, despite increased sensitivity to noise at low detection levels.

[0160] Therefore, if a transparent or partially obstructed object remains in the beam path for an extended period, the controller will indicate an increase in the signal associated with Δ. The controller can be characterized as having a limited response, since the permissible level of exposure to such a weak beam may be several minutes or even hours. This allows the controller to continue accurately monitoring the Δ signal over long periods to ensure it does not exceed the time limits for that power level required by the guidelines.

[0161] exist Figure 6BIn the example shown, the vase 64 can be removed from the beam path before the maximum permissible time period for the power level loss due to object 64 has been exceeded. Therefore, the delay time or wait period used by the system ensures that no unnecessary changes are made to the system.

[0162] Alternatively, if the vase 64 remains in the beam path close to the maximum permissible exposure for that power level, such that it exceeds the maximum "wait period" or delay time allowed before the system needs to be activated to shut down or the beam is deflected, then such action may be necessary before that maximum permissible exposure time is exceeded.

[0163] Therefore, the currently disclosed system ensures that, taking into account the small power loss between the transmitter and receiver, objects that cross the beam for a short time are not subject to as much attention as objects that travel in the beam path for a long time. Furthermore, the currently disclosed system achieves the sensitivity required for a large dynamic range while taking into account the required large dynamic range.

[0164] Now for reference Figure 7 , Figure 7 This is a flowchart illustrating one implementation of a method used when operating the currently public system.

[0165] In step 701, the "event clock" is started, and the system calculates the "wait period" (referred to as T). delay This refers to the length of time the system waits from the start of the "event clock" until the termination beam redirects if the Δ signal does not show a significant change, as will be explained below. According to the specification, T... Δ It is determined based on the permissible exposure time under the currently received Δ power. According to an exemplary method, in order to calculate T... delay The incremental signal is averaged, with the averaging time being less than the maximum permissible duration of the power loss. This ensures that abnormal readings (e.g., spikes caused by short noise interference) do not unnecessarily cause the "event clock" to be reset.

[0166] In step 702, the Δ signal is continuously measured.

[0167] In step 703, the system determines whether the level of the Δ signal has changed by more than a predetermined amount, indicated by Δ. ch The increase in the Δ signal indicates that more beam loss has occurred than calculated at step 701, therefore a different and shorter T must be calculated based on this increase in the Δ signal. delay Furthermore, the "event clock" or timing system must be reset to reflect this change. Conversely, a decrease in the Δ signal indicates a decrease in beam loss, and therefore a new, longer T can be calculated based on this decrease in the Δ signal.delay Furthermore, the "event clock" or timing system must be reset to reflect this change.

[0168] In an alternative embodiment of the system, if the indicated power loss is greater than a predetermined saturation level (above which all signals are responded to identically), the event clock is presented substantially uncorrelatedly because the system should terminate, blocking or redirecting the beam without delay. For example, an incremental signal indicating 95% beam blocking may cause the system to respond simultaneously with an incremental signal indicating 99% beam blocking. The saturation level can be selected as 10W or higher, or 9W or higher, or other power levels. The saturation level may depend on the environmental or other parameters of the wireless power system.

[0169] In step 704, if the indication Δ signal does not contain a value greater than Δ ch If the value changes, the system will assess whether it has exceeded the current T. delay If not, control returns to step 702 and continues measuring the Δ signal. On the other hand, if the indication exceeds T... delay Therefore, the allowable exposure duration will soon exceed the current power loss requirement, and control will then proceed to step 705.

[0170] In step 705, the system's operating parameters are activated to prevent excessive beam exposure, for example by blocking the beam, redirecting the beam, or terminating the beam.

[0171] Now for reference Figure 8A and Figure 8B It shows the permissible exposure time for different power levels in accordance with the aforementioned U.S. regulations. Figure 8A This is the response time required for a beam with a wavelength of 1050m. Figure 8B This is the response time required for a 2600nm wavelength beam. Therefore, the controller's wait period or delay time can be set such that the maximum delay before terminating the beam or affecting another parameter of the system is within the maximum allowable time for that power loss.

[0172] It should be recognized by those skilled in the art that this invention is not limited to the specific details shown and described above. Rather, the scope of this invention includes combinations and sub-combinations of the various features described above, as well as variations and modifications that would occur to those skilled in the art upon reading the above description and that are not found in the prior art.

Claims

1. A system for providing wireless power to at least one receiver, the system comprising: (a) A transmitter adapted to transmit a beam of wireless power; (b) A power meter configured to generate a first signal corresponding to the power level of the transmitted beam; (c) A detector associated with the at least one receiver and configured to generate a second signal corresponding to the power of a beam received at the receiver; (d) At least one controller, said at least one controller being adapted to perform the following operations: (i) Determine the time period T delay The T delay Less than the maximum safe exposure duration for the difference in power measured by the power meter and the detector; (ii) Continue to measure the difference in power, and: (a) If the difference in power has changed by more than a predetermined amount, then dynamically determine the new T. delay ; as well as (b) If it exceeds T delay If so, at least one operating parameter of the transmitter is modified to reduce the power difference.

2. The system according to claim 1, further comprising: A frequency selection signal processor is adapted to process signals corresponding to the difference in power.

3. The system according to claim 1 or 2, wherein, If the power difference is greater than a predetermined level, the controller is configured to modify the transmitter's operating parameters without waiting for a timeout of T. delay .

4. The system according to claim 2, wherein, The upper frequency limit of the passband of the frequency selection signal processor is set at a frequency commensurate with the response time to limit the exposure of signals to power differences corresponding to predetermined levels.

5. The system according to claim 2, wherein, The frequency selection signal processor is configured to shift its frequency response curve to a lower frequency than those indicated by the passband, which is required to provide amplification over the range of exposure durations expected by the power transmission system.

6. The system according to claim 5, wherein, The offset of the frequency response curve provides increased amplification to the low-level power difference signal, enabling the processor to respond to changes in these low-level signals.

7. The system according to claim 5, wherein, The offset of the frequency response curve provides increased amplification to the low-level power difference signals, enabling these low-level power difference signals to generate a processor output that is high enough above the noise level to trigger the laser safety routine.

8. The system according to claim 1, wherein, The controller is also configured to: transfer T delay The calculation is a function of the previously generated difference signal.

9. The system according to claim 8, wherein, A difference signal below a predetermined ambient level indicates that there is no significant beam obstruction between at least one transmitter and at least one receiver.

10. The system according to claim 8, wherein, If the difference signal drops below the ambient level within a predetermined time period, then T delay The generation is not significantly based on any prior differential signals.

11. The system according to claim 8, wherein, The system is configured to respond to any difference signal above ambient level by: For signals below a predetermined level but above the ambient level, calculate T. delay ,or For signals higher than the predetermined level, with T delay Respond in an irrelevant manner.

12. The system according to claim 8, wherein, The system is configured to respond to any differential signal above the ambient level by: calculating T for a signal below a predetermined level but above the ambient level. delay Alternatively, the operating parameters of the transmitter can be modified to reduce the incremental signal.

13. The system according to any one of claims 4 to 12, wherein, The frequency selection signal processor includes an amplifier.

14. The system according to claim 1, wherein, If the time elapsed from step (i) exceeds T delay Then proceed to step (iii).

15. The system according to claim 1, wherein, The modification of at least one operating parameter of the transmitter includes at least one of the following: Modify the power level of the beam; Completely terminate laser emission; Change the beam profile of the emitted beam; Block the beam; The beam can be guided by using a scanning mirror to direct the beam to different locations; Scan the area around the current scanning position to better align the beam onto the receiver; as well as Record the scan position of the marked object in the beam path.

16. A method for providing secure wireless power to at least one receiver, the method comprising: (a) Transmitting power from at least one transmitter to at least one receiver; (b) Generate a first signal corresponding to the level of the power transmitted by the at least one transmitter; (c) Generate a second signal corresponding to the level of power received at the at least one receiver; (d) Generate a difference signal, wherein the difference signal is the difference between the second signal and the first signal; (e) Determine the time period T delay The T delay Less than the maximum exposure duration associated with the safe exposure duration of the power indicated by the difference signal; (f) Monitor whether the difference signal has changed by a predetermined amount, and if the difference signal has changed by a predetermined amount, return to step (e); and (g) If it exceeds T delay If so, at least one operating parameter of the wireless power supply is modified to reduce the differential signal.

17. The method of claim 16, further comprising: Respond to difference signals above a predetermined level without using T delay To determine the time period to wait before modifying at least one operating parameter of the wireless power supply.

18. The method according to claim 16, wherein, The T is calculated by averaging the difference signals over the time period. delay This results in a difference signal indicating a high power level having a shorter average time compared to a difference signal indicating a lower power level, the amount of time depending on the power level indicated by the difference signal.

19. A system for transmitting laser power from a transmitter to at least one receiver, the system comprising a hazard prevention system, the hazard prevention system comprising: A power monitor that measures the optical power of the laser emitted from the transmitter; as well as A power sensor for measuring the optical power of the laser at the at least one receiver; The hazard prevention system is configured to reduce or terminate the power of the laser in response to an increase in the difference between the measurement of the power monitor and the measurement of the power sensor, after a time delay following the occurrence of the increase in difference, the time delay being measured in seconds as follows: in, The laser power is measured by the power monitor, in watts. in, The laser power is measured at the power sensor, in watts; and in, It is the laser wavelength, which is measured in nanometers.

20. A system for providing secure wireless power to at least one receiver, the system comprising: (a) A transmitter adapted to transmit a beam; (b) A power meter used to measure the power level of the emitted beam; (c) A detector associated with a receiver and configured to detect at least a portion of a beam received at the receiver; as well as (d) A frequency-selective signal processor, which is adapted as follows: (i) Generate a representation of the time period T delay The output signal of T delay Less than the maximum exposure duration associated with the safe exposure duration for the difference in power measured by the power meter and the detector; as well as (ii) Monitoring from T delay Since the determination of time, and if it exceeds T delay If so, at least one operating parameter of the transmitter is modified to reduce the difference; The frequency selection signal processor is configured such that if the output signal is higher than a predetermined level, the frequency selection signal processor has the following response characteristic: the frequency selection signal processor is independent of T. delay The operating parameters of the system are modified so that the frequency selection signal processor has a frequency response that is offset toward a lower frequency.

21. The system according to claim 20, wherein, The lower frequency is associated with an allowable exposure duration that is significantly longer than the allowable exposure duration for power exposure above the predetermined level.

22. A system for providing secure wireless power to at least one receiver, the system comprising: (a) A transmitter adapted to transmit a beam of wireless power; (b) A power meter configured to generate a first signal corresponding to the power level of the transmitted beam; (c) A detector associated with at least one receiver and configured to generate a second signal corresponding to the power of a beam received at the receiver; (d) At least one controller adapted to perform the following operations: (i) Determine the permissible cumulative energy exposure limit for the power level relative to the difference in power measured by the power meter and the detector; (ii) If the difference has changed by more than a significant amount, then a new energy limit is dynamically determined; as well as (iii) If the energy limit is exceeded, at least one operating parameter of the transmitter is modified to reduce the difference.

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