Wireless optical power transmission system with system status control
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-04
- Publication Date
- 2026-08-13
Smart Images
Figure IL2026050113_13082026_PF_FP_ABST
Abstract
Description
[0001] WIRELESS OPTICAL POWER TRANSMISSION SYSTEM WITH SYSTEM STATUS CONTROL FIELD
[0002] The present disclosure describes technology related to the field of optical wireless power transmission systems, especially for ensuring their safe operating procedures, both when the system is operating free of faults, but also when faults have occurred in any subsystems .
[0003] BACKGROUND
[0004] Optical wireless power systems operate by directing a beam of light, from a light source such as a laser or a light emitting diode source, from the transmitter to a receiver and converting the light into electricity in the receiver. Such systems typically include an illumination system, including the light source, electrical power driver and optics, a beam deflection system used to aim the beam in various directions and a receiver comprising a photovoltaic cell for receiving the light beam. Since optical wireless power systems require a line of sight between the transmitter and a receiver, the transmitter is generally installed on the ceiling of a room.
[0005] In order to allow such as system to transmit a light beam intense enough for supplying meaningful amounts of power, and since such levels of power are generally dangerous to the eye, an efficient safety system is an essential part of any such system. Furthermore, because the installation on the ceiling may be difficult to access, it may be difficult to provide maintenance of the system, to ensure smooth and safe operation, without physical access to the system.
[0006] Without physical access to the system, it is difficult for human operators to take responsibility for the safety of the system. Thus, while for a “hands-on” system, and operator may notice a damaged component, or overheating or even smoke coming out of the system as a result of a damaged circuit, in a system on the ceiling of a remote warehouse, for instance, such a fault may go unnoticed for lengthy periods. For that reason, optical radiation safety standards require the safety system to be single fault tolerant, such as in US CFR 21 -1040.10 f(2)(iii), which applies to laser sources, and where there is stated:“(Hi) Either multiple safety interlocks or a means to preclude removal or displacement of the interlocked portion of the protective housing shall be provided, if failure of a single interlock would allow:
[0007] (a) Human access to a level of laser radiation in excess of the accessible emission limits of Class Ilia; or
[0008] (b) Laser radiation in excess of the accessible emission limits of Class II to be emitted directly through the opening created by removal or displacement of the interlocked portion of the protective housing.”
[0009] The International safety regulation, IEC 60825-1, also has similar requirements, where, in section 5.1, there is stated:
[0010] “Tests during operation shall be used to determine the classification of the product. Tests during operation, maintenance and service shall also be used as appropriate to determine the requirements for safety interlocks, labels and information for the user. The above tests shall be made under each and every reasonably foreseeable single-fault condition.”
[0011] Other local optical radiation safety standards are typically based on either of the above mentioned standards, and require the handling of system failures accordingly. The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety.
[0012] SUMMARY
[0013] The present disclosure attempts to provide novel systems and methods that overcome at least some of the disadvantages of prior art systems and methods. The present disclosure describes new exemplary systems for control and monitoring of the operation of optical wireless power transmission systems, which provides supervision of the separate operational states of the system to ensure that the system operates safely even in the event of faults arising in components or modules of the system, or in the case of start up of the system following power supply interruptions, whether externally occurring, or because of an intentional power turnoff. The systems described in this disclosure define a number of distinct operating modes, and the system is controlled such that the operation of the various modes of the system enables efficient and safe transmission of the optical wireless power.Optical wireless power systems generally comprise several subsystems working in unison to perform the energy transmission. Firstly, the light source emits a light beam, which serves as the primary conduit for power transfer. The light beam direction is controlled by a beam deflection unit, which is tasked with scanning the light beam in different locations where a receiver might be expected to be found, while searching for a receiver, and then by accurately aiming the light beam towards a receiver found and validated, while charging the internal battery of the found receiver.
[0014] At the core of this system lies a controller that orchestrates the operations of both the light source and the beam deflection unit. This controller ensures that the light source's emission and the beam's direction are precisely managed to maximize efficiency and safety.
[0015] Supporting these components is a power supply system, which provides the necessary energy to power the light source, the beam deflection unit, the controller and all other elements of the transmitter. This power supply system is designed to be reliable, ensuring continuous operation under various conditions.
[0016] Adding to the system’s functionality is a communication port that allows for remote control of the transmitter. This port facilitates external commands and system adjustments, ensuring that the wireless power transmission can be managed from a distance with ease and flexibility.
[0017] The system is equipped with a comprehensive diagnostic system. This system monitors the operational status of some critical components, and ensuring that they are functioning correctly. It can detect, report, mitigate, and compensate for faults it detects, determine whether they are transient or permanent, and provide real-time feedback to operators, thereby maintaining the integrity and reliability of the wireless power transmission process. The diagnostic system may rely on the controller and on sensors placed on other components, or on data otherwise obtained, such as user instruction inputs, and may be, a separate piece of hardware.
[0018] The system further includes a non volatile memory unit for storing the system’s status, especially output from the diagnostic system.In addition, in the volatile memory may be stored specific data other than critical data such as the permanent fault information. Data that is prone to accumulation of errors should be stored in volatile memory and periodically erased. Specific examples of such data are data about transient events such as blocked directions, lists of current receivers, mapping of the vicinity of the transmitter, transmitted power, received power. However, a copy of these values can also be stored in nonvolatile memory, but the working copy of that data may be periodically erased. Such wireless power transmission systems have at least 5 important states, and typically more. Each of the 5 states is characterized by the operating conditions of at least 5 subsystems.
[0019] 1. The condition of the charging light source. The charging light source can be off, it can be emitting average power levels below the CW accessible emission limit (AEL), or it can be emitting average power levels above the CWAEL. The power level limits used are defined as average power levels, since such as when a series of short pulses with peak power above the CWAEL are used instead of a CW beam. This configuration may have the same safety limits but with easier thermal control. 2. The condition of the beam deflection module, which in low power mode, is typically not aiming at anything specific, or is even turned off. It can be in scan mode when it is not aiming in a direction where a receiver is known to be, or in charge mode, when it is aimed towards a direction where a receiver is known to be.
[0020] 3. The condition of the internal diagnostic system, which can have no fault indication, a transient fault indication, or a permanent fault indication.
[0021] 4. The condition of the power system, which may be powered or unpowered. In the case where an energy storage device is available, system can be powered from an external or an internal source.
[0022] 5. The remote control link may be active or inactive.
[0023] While there can be 72 or more combinations of the above list, and there can be even more states depending on more system components. Most systems do not implement all the above 72 or more states, but all wireless power systems must implement at least two of the states, namely the off state, characterized in that allsystems are off, especially the light source, and the charge state, characterized in that the light source is on and the beam deflection unit is aimed at a receiver.
[0024] The system described in the present disclosure, must implement at least the below mentioned 5 states:
[0025] (i) Normal low power, in which the light source is off or in a low power mode, the beam deflection system is off or in low power mode or in a mode designed to prolong it’s lifespan, or in a maintenance mode, the diagnostic system is in a no fault condition, the system is powered, and the remote control link is active.
[0026] (ii) Normal search, in which the light source is in low power mode, emitting less average power than the CW accessible emission limit, the beam deflection unit is in search mode pointing in various directions other than those where a receiver is known to be, the internal diagnostic system is in no fault condition, the power system is on and the remote control link may be either active or inactive.
[0027] (iii) Normal charge, in which the light source is in a high power mode, emitting more average power than the CW AEL, the beam deflection unit is in charge mode pointing in a direction where a receiver is known to be, the internal diagnostic system is in a no fault condition, the power system is on and the remote control link may be either active or inactive.
[0028] (iv) Permanent fault mode, in which the light source is off or in low power mode, emitting much less average power than the CWAEL, the beam deflection unit may be in any state, the internal diagnostic system is in permanent fault condition, the power system is on or off and the remote control link may be either active or inactive. (v) No-power mode, in which the power is off and the other components are also off. The above 5 states are related to herein as significant states.
[0029] However, even though the above described, controller defined, operational states provide well defined bounds in which the system operates, in order to provide a high level of safety to the system, and according to a further aspect of the operation of the systems, the controller must also ensure that the system cannot change state arbitrarily or accidentally, since switching from one state to another may involve an unsafe maneuver, enabling emission of hazardous optical beam transmission, in an unacceptable situation. According to this further feature of the present application,switching between the above described operational modes of the system is limited to certain combinations and is precluded in others, in order to prevent an unsafe situation from being generated unintentionally. All of these decisions are taken by the system automatically and safely.
[0030] In this additional aspect of the present application, only some transitions between the significant states are allowed to take place automatically in the system. Other transitions between the significant states are blocked by the system. If the system somehow performs a forbidden transition, the diagnostic system should detect it and correct it. The system may switch from a first significant state to a lesser significant state or states, or to a second significant state, as long as the transition between the first significant state and the second significant state is allowed.
[0031] The diagnostic system of the present disclosure has the function of allowing or forbidding transitions between the significant states, as well as detecting faults in the different safety-related subcomponents of the system.
[0032] The system may automatically switch to a no-power state from any other state, but prior to such transition, if the condition of the diagnostic system is changed and the switching occurs automatically and not due to a power failure, at least the condition of the diagnostic system is saved to non-volatile memory. The system may further save the condition of other subsystems to non-volatile memory.
[0033] The system may automatically switch from any state into the Permanent fault mode and will typically write the status of the diagnostic system to non-volatile memory upon doing so.
[0034] The system may only automatically switch from the no power state to normal low power if the nonvolatile memory indicates that it is not in permanent fault mode. The system may automatically switch to normal search from any state, except permanent fault, unless the nonvolatile memory indicates it should not be in permanent fault mode.
[0035] The system may automatically switch to normal charge only after it has passed through the normal search mode, and performed a handshake procedure between the receiver and the transmitter.The operational procedures followed in the systems of the present application, may be summarized in the following paragraphs.
[0036] In a first embodiment of the currently disclosed systems, upon receiving power the system checks the data stored in the non-volatile memory, if any, to determine whether a permanent fault is indicated.
[0037] If no such permanent fault is indicated, the system checks the non-volatile memory for generated data, based on the state of the system prior to initiating the previous no-power state, and selects the allowed state to which it can move.
[0038] If the state prior to the no power state was the normal low power or sleep state, the system switches to the normal search state. Some systems, though, are configured to wake up to normal low power or sleep mode, until a preconfigured remote command is received to start searching. This is a user configurable setting, while the default is to switch to normal search.
[0039] If the state prior to the no power state was normal search, the system switches to the normal search state unless a preconfigured command set by the user instructs the system to switch back to the normal low power state or the sleep state.
[0040] If the state prior to the no power state was charge, the system switches to the normal search state unless a preconfigured value set by the user instructs it to switch to the normal low power state or the sleep state.
[0041] Typically the remote control interface is turned on when switching from the no power state, even if the prior state of the remote control unit was off, especially in the permanent fault state.
[0042] An alternative set of operational procedures may be described as follows:
[0043] If the state prior to the no power state was normal search, the system switches to the normal search state.
[0044] The user may instruct the system to switch to normal search state and to at least one of normal low power state and no power state, through the remote control interface.
[0045] At least one of normal low power state and normal search state will have the remote control interface on and waiting for instructionsAfter being in search mode, continuously for a time exceeding a predetermined threshold, the system will automatically switch to normal low power state.
[0046] The system may, after being in normal low power state for a time exceeding a second threshold, automatically switch to search mode without a user instruction through the remote-control interface.
[0047] A fuller description of the different system states and of the allowed and prohibited transitions, are found in the detailed description section hereinbelow.
[0048] Even though all of the transition rules are important in their own right, there are some transitions which may be considered to be the most critical, since they directly and immediately involve the safety of use of the system. Some such examples are, for instance that:
[0049] The system is never allowed to wake-up in charge mode.
[0050] The system wakes up from sleep mode into an operational mode, which can be search or low power mode, which is eventually turned into search mode.
[0051] The system switches from the scan state to the low power state before resuming its scan state.
[0052] There is thus provided, in accordance with an exemplary implementation of the systems described in this disclosure, a transmission system for safe transmission of wireless power to a receiver, the transmission system comprising:
[0053] (a) a light source adapted to emit a beam having a wavelength, the light source having at least two operating modes, (i) at least one low power mode characterized in that the light source is either off or is emitting average power below the continuous wave accessible emission limit according to a relevant optical radiation safety standard for the light wavelength, and (ii) at least one high power mode characterized in that the light source is emitting average power above the continuous wave accessible emission limit for the lightwavelength set in the relevant optical radiation safety standard;
[0054] (b) a beam deflection unit having at least three operating modes, (i) a sleep mode in which the beam deflection unit is not actuated, (ii) a search mode in which the beam deflection unit aims the light beam into multiple directions in which the presence of a receiver is not known, and (iii) a charge mode in which the beamdeflection unit aims the light source towards a direction where a receiver is known to be;
[0055] (c) a non-volatile memory unit;
[0056] (d) a control system, configured to control at least the light source and the operating mode of the beam deflection unit;
[0057] (e) a diagnostic system adapted to detect faults in the transmitter which could be dangerous, and, if such a detected fault is categorized as a permanent fault, based on a predefined condition, to store information regarding the permanent fault in the non-volatile memory and to cause the light source to enter the low power mode; and
[0058] (f) a power system for supplying power to the wireless optical power transmitter;
[0059] wherein, the transmitter has at least five operational states:
[0060] (i) a sleep mode state characterized in the light source being in a low power mode, the control system being operational, the beam deflection mode being in sleep mode, and the power system being on;
[0061] (ii) a charge mode state characterized in the light source being in a high power mode, the control system being operational, the beam deflection mode being in a charge mode, and the power system being on;
[0062] (iii) a search mode state characterized in the light source being in a low power mode, the control system being operational, the beam deflection mode being in search mode, and the power system being on;
[0063] (iv) a permanent fault state characterized in the light source being in a low power mode, the power system being on and the non volatile memory unit indicating that the transmission system has a permanent fault; and
[0064] (v) an off state characterized in the power system being off;
[0065] and wherein the controller is configured to regulate the operation of the light source emission and the beam deflection unit to enable the system to provide safe transmission of wireless power to the receiver.
[0066] In the above described systems, safe transmission of wireless power to the receiver is achieved by configuring the controller to, at least, limit transitions between the five operational states of the transmitter states, in which:(i) the transmission system can switch from the sleep mode state to the search mode state but is precluded from switching from the sleep mode state to the charge mode state directly;
[0067] (ii) the transmission system can switch from the search mode state to the charge mode state;
[0068] (iii) the transmission system automatically switches from the search mode state to the sleep mode state if it has not switched to the charge mode state for a time longer than a threshold time;
[0069] (iv) the transmission system is precluded from automatically switching from the off mode state to the sleep mode state, the charge mode state, or the search mode state;
[0070] (v) the transmission system is configured to prevent switching from the off mode state to the sleep mode state or to the search mode state, if the state of the transmission system prior to entering the off mode state was in the permanent fault mode state;
[0071] (vi) the transmission system is configured to switch from the permanent mode state to the search mode state or to the sleep mode state, if the state of the transmission system prior to entering the permanent fault mode state was in the charge mode state or the search mode state; and
[0072] (vii) the transmission system is configured to switch from the off mode state into the permanent fault mode state if the state of the transmission system prior to entering the off mode state was in the permanent fault mode state.
[0073] Such a transmission system, after being in either the charge mode state or the search mode state for a cumulative time longer than a predetermined threshold, may be further configured to turn the light source off and to perform diagnostic operations. In such a case, the system may be further configured to switch to the sleep mode state or the search mode state after completing the diagnostic operations.
[0074] In any of the above described transmission systems, the system for undertaking the diagnostic operations may be incorporated within the control system. Additionally, the control system may be remote from the transmission system.Furthermore, in any such transmission systems, the sleep mode state, in which the beam deflection unit is not actuated, should be entered after a predetermined time of unsuccessful searching by the transmission system.
[0075] In any of the above described transmission systems involving allowed or forbidden switching between states, the transmission system can switch from the search mode state to the charge mode state only after identification of the receiver with high enough confidence to believe that it is a valid receiver to which charging power can be directed.
[0076] According to yet a further exemplary implementation, in the event of a termination of power to the transmission system, on return of power, and provided that the nonvolatile memory does not show that the system is in a permanent fault state, the control system may be configured to turn on the system in either the sleep mode state or in the search mode state, according to a user configurable choice. In such cases, a preferred choice is for the system to turn on in in the search mode state, in order to increase system efficiency. Furthermore, on return of power, the control system must prevent the system from returning to the charge mode state.
[0077] BRIEF DESCRIPTION OF THE DRAWINGS
[0078] The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: Fig.1 shows an exemplary situation in a light source power transmission system, which illustrates one aspect of the need for the systems and methods described in the present application;
[0079] Fig. 2 shows the basic five states of the system, and the allowed and prohibited transitions between these states;
[0080] Fig. 3 describes which states the system is allowed to switch to, after reinstatement of power to the system, as a function of the state the system was in before the power was disconnected;
[0081] Fig. 4 describes the behavior of the system from power on, depicted as a flowchart; andFig. 5 is an exemplary block diagram of the components of a complete system incorporating the procedures of this application, for ensuring operation in accordance with the rules providing the required safety procedures of the system.
[0082] DETAILED DESCRIPTION
[0083] Reference is first made to Fig. 1, which shows an exemplary situation, which is useful for illustrating one aspect of the need for the systems and methods described in the present application. In Fig. 1, there is shown schematically a light source 10 connected to its electrical power source 11 via two switches 12,13, one located in the power line to the light source, and the other in the power line from the light source. Each switch has its own safety system and these two safety systems control both connectors of the safety system such that each safety system can independently prevent the light source from turning on.
[0084] Such a system can be designed to comply with the requirements of optical radiation safety standards, as is known in the art, for example in International Patent Application Publication No. WO / 2019 / 064305, commonly owned by the present applicant.
[0085] However, should switch 12 for example, become faulty by being permanently conductive at some point of time, this fault would not prevent the system from continuing to provide optical power without any immediate danger. However, under that condition, a subsequent failure in switch 13 could then cause the system to become dangerous.
[0086] To avoid such a problem, the system of which Fig. 1 is a part, should include a diagnostic system, which will detect a failure in either of the switches, and will keep the light source off, until a qualified person undertakes repairs, and approves the system for use.
[0087] A wide range of other potential problems could arise with any electronic or electronically controlled physically-based systems, and in the present disclosure, there is described an exemplary self-diagnosis system, configured to detect faults in the safety system. As mentioned in International Patent Application Publication No. W02024 / 009305, also commonly owned by the present applicant, such a faultmay be either permanent or transient, and the system described in that system maintains the safe state of the light beam.
[0088] In the context of Fig. 1 above, the system described in W02024 / 009305A1 should keep the non-faulty switch in the non-conductive state, and this would be safe in most situations.
[0089] However, after disconnection from power, the controller would reboot the system normally. After reboot the diagnostic system of the present disclosure would detect the fault again, and would keep the system in a safe state. This is thus consistent with the requirement for single fault tolerance in optical radiation safety standards. Thus, while for a human operated system the requirement to remain safe under fault is sufficient and may be fulfilled by turning the light source off, perhaps with some notice to the user, such as a warning light, which the operator is expected to notice and attend to the problem, with an unattended optical power system, this may not be the case. In currently available unattended systems, the first fault may lurk for years, only waiting for a second fault to happen and cause the system to become potentially dangerous to personnel in its area.
[0090] On the other hand, in the systems of the present disclosure, some faults should, upon detection, disable the system completely, or at least until a qualified human operator has effected a repair and has determined that operation is safe and the problem is fixed. This feature is especially important for use in unattended wireless power supply systems installed in difficult-to-reach locations, such as on a ceiling. Reference is now made to Fig 2, which shows the basic five states of the system, and the allowed and prohibited transitions between these states. These include three legacy states, namely “No power” 101, “Normal search” 104 and “Charge” 103, which exist in previously known systems, and two additional states “Permanent fault” 105 and “Normal low power” 102, the latter of which also includes sleep modes. The flowchart of Fig. 2 describes the allowed paths the system may take in moving between states, the paths being described as “allowed paths” since in some situations, the system is precluded from switching directly from certain states to other states. The preclusion of transitions between states may be executed in software or in hardware, and should be monitored by at least two subsystems or processes. Such systems are typically controlled by a controller, and suchcontrollers may comprise hundreds of millions of individual components, typically billions, which cooperatively execute tens of thousands, or many more, of instructions, relying on dozens of configuration and calibration parameters received from multiple sources. Because of this complexity, such systems are prone to unexpected and unrequested switching between states, sometimes in a forbidden manner. Typically, there is either some simple code, executed in a separate thread or an external component, which monitors the state of the system, in order to to detect anomalies. On detecting an anomaly, the system is typically switched to a safe state, such as one of states 101, 102, or 105 in Fig. 2, and in rare circumstances, 104, but never to the Charge state 103. In Fig. 2, transitions which are always allowed are designated by a full lined arrow, and transitions which are only allowed if a permanent fault is not indicated, are designated by a dashed line arrow.
[0091] The 5 basic states may be described as follows:
[0092] State 101 , “No power”, is the state of the system when power is unavailable, or when the user or system controller brings the system to the “no power” state.
[0093] State 105, is a permanent fault state. When the system reaches the permanent fault state, it is allowed to switch only to the “no power” state 101, or to the low power mode state 102, or to remain in the permanent fault 105 state, unless an external instruction, signal or intervention occurs. When the system is switched to the permanent fault 105 state, that information is recorded in the system nonvolatile memory so that the controller can be prevented from switching to any state other than states 101 and 102. This state typically includes some form of user or operator notification, such as a warning light and electronic signaling through a communication channel. In this state, the light source is kept off or at a very low power level, while communication systems may be actuated, and even preferably, are actuated, to allow the system to report its non-charging status to the user or operator. The system remains in permanent fault state 105, until the cause of the fault is rectified.
[0094] State 103 is the state of the system when it is charging a receiver. In this state the light source is outputting at a high power level, the beam deflection unit is aiming the light beam at a receiver, the safety system is operating, and is configured toterminate or pause state 103 in case of detection of an intrusion into the beam. Communication systems are typically turned on, in order to report to the system controller, the progress of powering and charging, or any receiver identification data, and other operational data. The system can only reach state 103 from state 104, which is the normal search mode, and therefore knows with a high degree of certainty, that a receiver has been detected for receiving the charge. Furthermore, it can only do so if it is not in a permanent fault state 105. Such a situation could occur, for instance, if the system were in state 104, searching for a receiver, and a permanent fault is detected concurrently with the conditions being met to switch to charging state 103. The system has not yet executed the instruction to move to the permanent fault state, but the diagnostic system should ensure that it does so, and should not enable switching to the charge state. The system can typically switch from state 103 into any other state. If the system had switched to state 103 as a result of a fault, the fault should be detected and the system quickly switched to the fault state 105 or the no power state 101.
[0095] State 104 is the normal search state. This state is the only state which allows switching to the charge state 103. In this state the system identifies the location of a receiver, the light source is emitting at a lower power setting, below the maximal permissible exposure level, and is also used to identify the receiver with high enough confidence to allow the safety system to communicate with the receiver, with the belief that it is communicating with a valid receiver. The latter feature is very important as without that affirmative knowledge, safety can be easily compromised. Almost all safety systems used for optical wireless power systems require positive identification of the receiver to be charged by the light beam. Typically this state involves scanning the vicinity of the transmitter until something resembling a receiver is identified, followed by thorough investigation of the identity of the object detected, until it is verified positively, with high reliability, as a legitimate receiver. Once this fact has been established, the system may switch to the charging state 103. The system may switch at any time to the normal low power mode 102 If a receiver has not been found for a time exceeding a time T, which may be either predetermined, or decided intra-operationally, based on available data, the system should switch automatically to the low power 102 mode. The lifetime of the bearings of the beam deflection mirror can be significantly increased by limiting the time thatthe system scans pointlessly, while trying to find a receiver to charge, During the search mode 104, the beam deflection module is on and is typically performing a scan, the light emission unit is on at a power level below both the AEL (accessible emission limit) and the MPE (maximum permissible exposure limit). The controller is powered and communication channels are typically also open, reporting when a receiver is found.
[0096] Normal search state 104 is typically configured to automatically switch to normal low power state 102, such as in at least some of the following cases:
[0097] (a) When the normal scan state 104 has continued for a long, predetermined time T, without switching to the charge state 103 or to the normal low power state 102. (b) When instructed to do so by an external system or an operator.
[0098] (c) When the temperature of the system exceeds a predetermined limit.
[0099] (d) When the number of available receivers is known, and all of the receivers have reported no need for power
[0100] (e) When a gas leak is detected, or a high level of humidity is detected in the air. (f) When there is condensation on the transmitter for an inordinate time.
[0101] (f) According to a schedule.
[0102] (g) When an external interference prevents the system from operating satisfactorily, such as when there is a strong interference in the communication channels or when direct sunlight blinds an optical system, or when rain or dust, or any other air-borne interference in the air interferes with transmission.
[0103] Normal low power state 102, is characterized in the beam deflection unit and the light source unit as being in a low fatigue state. A low fatigue mode is a state in which the bearings and springs of the beam deflection unit are experiencing reduced aging. This can mean either locking the beam deflection device towards a specific direction, but in some control systems, this may cause the mirror to attempt to perform small corrections all the time and experience larger fatigue, in which case disconnecting the control of the system is the optimum “low fatigue mode”. For the light source itself, the low fatigue mode is usually the off state, but in some systems it is advisable not to allow the light source to cool down, as excessive cooling-heating cycles may also cause fatigue. Since charging and searching are not performed in this state, other electronic sub-systems may be in sleep or low power modes. In some cases, a low fatigue state is achieved by turning the beam deflector and the light source off, turning the communication module on, and turning a timer on, at the end of which the system can return to the normal search state 104. Other options connect the beam deflection unit and its control with an impedance, selected to improve the longevity of the device.
[0104] The beam deflection unit may comprise a mirror positioned on at least two actuators. Each actuator comprises a coil and a magnet, and optionally also a spring. The magnetic field pushes or pulls the magnet in order to move the mirror to the required direction.
[0105] Each of these actuators has at least one resonant frequency, and often more than one. The resonant frequencies are a function of mechanical resonances coupled with the frequencies of electronic LC and RLC circuitry.
[0106] During normal low power state 102, the impedance represented by the controlling circuit on the beam deflection unit coils, is chosen so that audio frequencies between 5Hz and 50kHz, which are very common in office, commercial and residential environments, are attenuated. This is performed so that the beam deflection unit bearings are not stressed by external vibrations, and the beam deflection unit lifetime is this extended. In order to achieve this, in one exemplary solution, a resistance at least two times greater than the coil impedance at 5hz, is applied to the input of the coils.
[0107] Furthermore the oscillations caused by audio frequencies between 5Hz and 50kHz must not create a vibration amplitude greater than that which the natural flexibility of the beam deflection device can withstand, typically a maximum of about 0.02° or even as small as 0.001° is desired. This limitation can be achieved partially by increasing the friction of the bearings, in combination with increasing the flexibility of the mounting parts of the beam deflection unit. However, increasing the friction beyond a predetermined minimal value, increases the power consumption of the beam deflection unit, while increasing the flexibility, in many cases, results in lower beam aiming accuracy.While these solutions are good to a certain extent, and provide most of the desired limitations, additional passive electronic quenching may be applied to further reduce vibrations in the 5hz-50Khz regime, by applying the correct impedance to the input of the coils of the beam deflection unit, during the normal low power 102 state. Reference is now made to Fig. 3, which describes, after reinstatement of power to the system, which states the system is allowed to switch to, as a function of the state the system was in before the power was disconnected. This applies whether the power-off situation was purposefully executed, or whether from a fault in the power supply,
[0108] If the system is in the permanent fault state 201 when the power was turned off or turned off because of a power failure, this permanent fault state should have been marked in the non-volatile memory. When power stops, the system will switch to the no power state 202. When power returns, the system will query the non-volatile memory record and switch as soon as possible back to the permanent fault 201 state.
[0109] If the system was in the normal low power / sleep state 204 before the power was turned off, after turn-off, the system will switch to the no power 202 state. When power returns the system will turn on in either the normal search 205 state or in the normal low power 204 state. This is usually user configurable, with the preferred value being to wake up to normal search mode. In any event, the system is prevented from switching to charge mode 206 automatically upon power-on. If the system is configured to wake up in the normal low power / sleep mode, it would be configured to automatically switch to search mode from the normal low power / sleep mode, without user intervention, even though this reconfiguration may not be immediate.
[0110] If the system is in normal search 205 state before the power is turned off, after turnoff the system will switch to the no-power 202 state. When power returns the system will turn on either in the normal search 205 state or in the normal low power 204 state (not shown in Fig. 3). This is usually user configurable and the preferred value is to wake up to normal search 205 mode. In any event, the system is prevented from switching to charge mode 206 automatically upon power on.If the system is in charge state 206 before the power is turned off, after turn-off the system will switch to the no power 202 state. When power returns the system will turn on in either the normal search 205 state or in the normal low power 204 state (not shown in Fig. 3). This is usually user configurable and the preferred value is to wake up to normal search 205 mode. In any event, the system is prevented from switching to charge mode 206 automatically upon power on even though it was in that state before power turned off.
[0111] Reference is now made to Fig. 4, which describes the behavior of the system from power on, depicted as a flowchart.
[0112] When the system receives power after being disconnected for some time from its power source, it initially enters stage 301, power-on. Following, or in parallel to, the power-on self test, in step 302 the system reads the content of the nonvolatile memory unit, which has stored information about the state of the system before the power-off occurrence. In step 303, if the memory record indicates a permanent fault state, the system switches to the permanent fault 304 state and remains there until an external intervention occurs.
[0113] If the system has not switched to the permanent fault state 303, then in steps 305a, 305b, and 305c the system switches the machine state based on the previous state, if known, 305a represents the normal charging state as the previous state, 305b represents the searching state as the previous state, and 305c represents the normal low power / sleeping state as the previous state, If the previous state is unknown, 305d, it is usually assumed to be normal search.
[0114] In step 306a, 306b, 306c, 306d, the system checks whether any user action has initiated a different preference, and if not, the system will, in step 307, switch to the default state of normal search. The above-mentioned user-initiated action could have instructed the system to switch to normal low power at this step. If a fault is detected, it should switch to permanent fault, but in no circumstances, can the system switch to charge mode at this state.
[0115] If the search step 307 is completed successfully, the system periodically performs step 308, in which validation is performed that everything is operating safely. If some safety problem is revealed in step 308, then in step 309, the system writes theinformation regarding the fault to the non-volatile memory and additionally goes into the permanent fault state 304.
[0116] On the other hand, if no fault is detected in step 308, optional step 310 writes that information to the system log, and then, if at step 311 the conditions to switch to charging mode are met, such as, for instance, validation of a receiver in the beam and its direction, then charging state may commence in step 312. If the conditions to switch to charging mode are not met, then the system returns to step 307, to continue with the normal search procedure to find another receiver to charge, or to discover that the previous receiver has now been validated.
[0117] As previously described, if step 312 is not achieved for a time exceeding some predetermined threshold, the system will switch to the normal low power / sleep mode and shall remain their for a limited time. After remaining in normal low power / sleep state for that limited time, the system will automatically switch to the normal search step 307.
[0118] Reference is now made to Fig 5, which is a block diagram of the components of a complete system incorporating the procedures for ensuring operation in accordance with the rules providing the required safety procedures of the system.
[0119] The current system comprises a transmitter 501 and a receiver 502. The transmitter 501 comprises a beam generator module 504 capable of emitting a light beam having at least two power states, a search power state having lower power settings and a charge power state having higher power settings. The module typically also includes optics to bring the beam to the required diameter and convergence values, a n electronic driver to provide the correct power supplies to the beam generator module, and sensors to check that the module is functioning safely. Such sensors are used to detect permanent faults as well as for other tasks.
[0120] The transmitter further comprises a beam deflection module 505 capable of performing search operations in order to locate and identify receivers 502, as well as then maintaining the direction of the beam onto the receiver 502 which the search mode has found.The transmitter further comprises a controller 507 to control the electronic driver and the beam deflection unit 505 and a non-volatile memory unit, which can conveniently be located inside the controller, for storing information about the system.
[0121] The transmitter further comprising a power supply 509, which may include a battery unit 512, and a communication modem (not shown in the drawing) to allow the user or a remote system to remotely control the system.
[0122] The transmitter further comprises the diagnostic system 513 described in this application, which, though not thus shown in the drawing, in many cases will be implemented, at least partially, on the controller, to detect both permanent and nonpermanent faults.
[0123] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. Furthermore, it is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.
Claims
CLAIMSWe claim:
1. A system for safe transmission of wireless power to a receiver, the transmission system comprising:a light source adapted to emit a beam having a wavelength, the light source having at least two operating modes, (i) at least one low power mode characterized in that the light source is either off or is emitting average power below the continuous wave accessible emission limit according to a relevant optical radiation safety standard for the light wavelength, and (ii) at least one high power mode characterized in that the light source is emitting average power above the continuous wave accessible emission limit for the lightwavelength set in the relevant optical radiation safety standard;a beam deflection unit having at least three operating modes, (i) a sleep mode in which the beam deflection unit is not actuated, (ii) a search mode in which the beam deflection unit aims the light beam into multiple directions in which the presence of a receiver is not known, and (iii) a charge mode in which the beam deflection unit aims the light source towards a direction where a receiver is known to be;a non-volatile memory unit;a control system, configured to control at least the light source and the operating mode of the beam deflection unit;a diagnostic system adapted to detect faults in the transmitter which could be dangerous, and, if such a detected fault is categorized as a permanent fault, based on a predefined condition, to store information regarding the permanent fault in the non-volatile memory and to cause the light source to enter the low power mode; anda power system for supplying power to the wireless optical power transmitter;wherein the transmitter has at least five operational states:(i) a sleep mode state characterized in the light source being in a low power mode, the control system being operational, the beam deflection mode being in sleep mode, and the power system being on;(ii) a charge mode state characterized in the light source being in a high power mode, the control system being operational, the beam deflection mode being in a charge mode, and the power system being on;(iii) a search mode state characterized in the light source being in a low power mode, the control system being operational, the beam deflection mode being in search mode, and the power system being on;(iv) a permanent fault state characterized in the light source being in a low power mode, the power system being on and the non volatile memory unit indicating that the transmission system has a permanent fault; and(v) an off state characterized in the power system being off;and wherein the controller is configured to regulate the operation of the light source emission and the beam deflection unit to enable the system to provide safe transmission of wireless power to the receiver.
2. The transmission system according to claim 1 , wherein safe transmission of wireless power to the receiver is achieved by configuring the controller to, at least, limit transitions between the five operational states of the transmitter states, in which:the transmission system can switch from the sleep mode state to the search mode state but is precluded from switching from the sleep mode state to the charge mode state directly;the transmission system can switch from the search mode state to the charge mode state;the transmission system automatically switches from the search mode state to the sleep mode state if it has not switched to the charge mode state for a time longer than a threshold time;the transmission system is precluded from automatically switching from the off mode state to the sleep mode state, the charge mode state, or the search mode state;the transmission system is configured to prevent switching from the off mode state to the sleep mode state or to the search mode state, if the state of the transmission system prior to entering the off mode state was in the permanent fault mode state;the transmission system is configured to switch from the permanent mode state to the search mode state or to the sleep mode state, if the state of the transmission system prior to entering the permanent fault mode state was in the charge mode state or the search mode state; andthe transmission system is configured to switch from the off mode state into the permanent fault mode state if the state of the transmission system prior to entering the off mode state was in the permanent fault mode state.
3. The transmission system according to claim 2, wherein the system is further configured, after being in either the charge mode state or the search mode state for a cumulative time longer than a predetermined threshold, to turn the light source off and to perform diagnostic operations.
4. The transmission system according to claim 3, wherein the system is further configured, to switch to the sleep mode state or the search mode state after completing the diagnostic operations.
5. The transmission system according to any of the previous claims, wherein the system for undertaking the diagnostic operations is incorporated within the control system.
6. The transmission system according to any of the previous claims, wherein the control system is remote from the transmission system.
7. The transmission system according to any of the previous claims, wherein the sleep mode state, in which the beam deflection unit is not actuated, is entered after a predetermined time of unsuccessful searching by the transmission system.
8. The transmission system according to any of the previous claims 2 to 7, wherein the transmission system can switch from the search mode state to the charge mode state only after identification of the receiver with high enough confidence to believe that it is a valid receiver to which charging power can be directed.
9. The transmission system according to any of the previous claims, wherein, in the event of a termination of power to the system, on return of power, provided that the non-volatile memory does not show that the system is in a permanent faultstate, the control system is configured to turn on the system in either the sleep mode state, or in the search mode state, according to a user configurable choice.
10. The transmission system according to claim 9, wherein a preferred choice is for the system to turn on in in the search mode state, in order to increase system efficiency.
11. The transmission system according to either of claim 9 and 10, wherein on return of power, the control system prevents the system from returning to the charge mode state.