JP6619770B2 - Wireless power transmission system and method for protecting wireless power transmission system - Google Patents

Description

  The present invention relates to a wireless power transmission system and a method for protecting a wireless power transmission system.

  In recent years, an increasing number of devices adopt wireless power transmission technology that transmits power without using metal contacts or connectors. Wireless power transmission is also called wireless power feeding or contactless power transmission.

  This wireless power transmission can be broadly classified into a system that converts power into electromagnetic waves (microwaves) and feeds power, a system that uses the resonance phenomenon of electric field coupling, and a system that uses magnetic field coupling. As a type that utilizes the magnetic field resonance phenomenon due to the magnetic field coupling, there is an invention described in Patent Document 1, for example.

  As a solution to the abstract of Patent Document 1, “the power is transmitted from the feeding coil L2 to the receiving coil L3 by magnetic resonance. The VCO 202 turns on the switching transistor Q1 and the switching transistor Q2 alternately at the drive frequency fo. Turn off, supply AC power to the feeding coil L2, and supply AC power from the feeding coil L2 to the receiving coil L3, the phase detection circuit 114 detects the phase difference between the current phase and the voltage phase, and the VCO 202 detects this phase difference. The drive frequency fo is adjusted so that the current becomes zero.When the load voltage changes, the detected value of the current phase is adjusted, and as a result, the drive frequency fo is adjusted. "

JP 2011-139621 A

In order to stabilize the rectified voltage value of the wireless power transmission system, it is conceivable that the rectified voltage value information is fed back to the power feeding device wirelessly. In such a wireless power transmission system using wireless communication data, for example, a voltage value is periodically transmitted from a power receiving device to a power feeding device via a wireless module (Bluetooth (registered trademark)). The power supply apparatus performs feedback control based on the received voltage value.
In such a wireless power transmission system, a delay in control due to data creation processing and communication processing occurs regularly. Furthermore, communication data is delayed or lost due to interference from other wireless communication devices, electromagnetic noise, or the like, and the communication cycle varies. In consideration of this control delay, the time constant of the error amplifier that controls the inverter circuit may be set longer than the communication cycle. However, there is a problem that even if the expected rectified voltage fluctuation (voltage fluctuation accompanying an instruction from the host system) is detected, the protective operation is performed when the rectified voltage exceeds a predetermined voltage range.

When a load, which is a host system of the power receiving apparatus, uses the rectified voltage after being stepped down, the rectified voltage may temporarily fall outside the predetermined voltage range. As a result, when the power feeding device stops wireless power feeding, for example, as a protection operation, the power receiving device and its load may not be able to operate.
Therefore, an object of the present invention is not to perform a protection operation against an expected fluctuation in the rectified voltage in a wireless power transmission system.

In order to solve the above-described problem, a wireless power transmission system of the present invention includes a power feeding device and a power receiving device.
The power supply device controls a power supply coil that wirelessly transmits power, an inverter that drives the power supply coil, a first wireless unit that wirelessly communicates with the power receiving device, and the first wireless unit and the inverter. And a first processor.
The power receiving device includes a power receiving coil and a capacitor that wirelessly receive power from the power feeding coil of the power feeding device, a resonance circuit that generates a resonance voltage, and a rectification circuit that rectifies the resonance voltage and outputs a rectified voltage; A load driven by the rectified voltage; a second wireless unit that wirelessly communicates with the first wireless unit included in the power supply apparatus; and a second processor that controls the load and the second wireless unit. Is provided.
The second processor generates rectified voltage value information based on the rectified voltage, and sets or clears fluctuation information indicating that the fluctuation of the rectified voltage value is expected, and Information including the rectified voltage value and the fluctuation information is transmitted to the first wireless unit included in the apparatus.
Other means will be described in the embodiment for carrying out the invention.

  According to the present invention, the operation of the host system can be continued when the expected fluctuation of the rectified voltage occurs in the wireless power transmission system.

1 is a schematic configuration diagram showing a wireless power transmission system in an embodiment. It is a block diagram of a control circuit. It is a block diagram which shows a wireless power transmission system. 3 is a flowchart (part 1) illustrating processing of the power receiving apparatus. 6 is a flowchart (part 2) illustrating processing of the power receiving apparatus. It is a figure which shows the threshold value table which stored the response | compatibility of operation or load fluctuation | variation, and the threshold value of a fluctuation | variation counter. It is a flowchart (the 1) which shows the process of an electric power feeder. 6 is a flowchart (part 2) illustrating processing of the power feeding apparatus. It is a timing chart which shows the time of normal operation. It is a timing chart which shows the case where the voltage of the power receiving side is outside the range of the predetermined voltage over a predetermined period. Timing when the fluctuation flag is set, the fluctuation counter is counted, the voltage on the power receiving side is outside the predetermined voltage range for a predetermined period or more, and the difference from the target value changes It is a chart.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram showing a wireless power transmission system S in the present embodiment.
The wireless power transmission system S is a system in which the power feeding device 1 transmits power to the power receiving device 2 by magnetic field coupling. Hereinafter, the configurations of the power feeding side and the power receiving side will be described.

  The power supply device 1 on the power supply side includes a DC power supply 18, a control circuit 11, an inverter circuit 12, a power supply coil L 1, an initial voltage control circuit 13, a wireless module M 1, a step-down circuit Re 1, an operation unit 19, and a notification unit 10. Is done.

  The control circuit 11 generates gate signals G1 to G4 based on signals output from the initial voltage control circuit 13 and the wireless module M1, and controls the inverter circuit 12. The gate signals G1 to G4 are drive control signals for controlling the inverter circuit 12. The power supply terminal VDC of the control circuit 11 is connected to the direct current power supply 18, and the control circuit 11 operates when the direct current voltage Vdc is applied. Further, the control circuit 11 applies a predetermined constant voltage Vreg to the initial voltage control circuit 13 from the constant voltage terminal VREG. The control circuit 11 generates gate signals G1 to G4 so as to variably control the on-duty of the pulse power based on the rectified voltage information received by the wireless module M1, and controls the inverter circuit 12.

  The inverter circuit 12 is a full bridge circuit composed of, for example, PMOS (Q1, Q2) and NMOS (Q3, Q4), and outputs pulse power for driving at the resonance frequency on the power receiving device 2 side to the feeding coil L1. . The inverter circuit 12 is connected to a DC power source 18 and operates by applying a DC voltage Vdc. The inverter circuit 12 applies a rectangular wave voltage to the feeding coil L1. A triangular wave (sawtooth) current flows through the feeding coil L <b> 1 and wirelessly transmits power to the power receiving device 2. Note that the inverter circuit 12 may be composed entirely of NMOS.

  The initial voltage control circuit 13 includes an initial voltage setting circuit 14 that sets an initial voltage, and an initial voltage setting cancellation circuit 15 that cancels the setting of the initial voltage. Specifically, the initial voltage setting circuit 14 includes voltage dividing resistors R1 and R2. The initial voltage setting release circuit 15 includes a transistor Q5, and has a function of dropping the node of the initial voltage, which is a connection point of the voltage dividing resistors R1 and R2, to the ground potential. The initial voltage control circuit 13 operates by applying a predetermined constant voltage Vreg from the constant voltage terminal VREG of the control circuit 11, and outputs an initial drive control signal Ss to the terminal FB1. The control circuit 11 sets an initial value of the on-duty of the gate signals G1 to G4 based on the initial drive control signal Ss. At this time, the wireless power feeding is in an idle state, and a secondary power supply unit 28 of the power receiving device 2 described later supplies a first predetermined voltage Va1 (for example, 5V) at which the wireless module M2 can operate.

The wireless module M1 includes, for example, a wireless unit 16 compliant with Bluetooth (registered trademark) Low Energy and a processor 17. The wireless unit 16 (first wireless unit) has a function of transmitting and receiving signals to and from the wireless unit 26 of the power receiving device 2 via a wireless communication path. The electric field strength of the wireless unit 16 and the electric field strength of the wireless unit 26 described later are both 35 μV / m or less.
The communication between the wireless unit 16 and the wireless unit 26 is not limited to radio wave communication, and may be wireless communication such as visible light communication, infrared communication, or ultrasonic communication, and is not limited.

The processor 17 (first processor) is, for example, a microcomputer including a storage unit and a processing device, and controls the control circuit 11 and the initial voltage setting cancellation circuit 15 by executing a power supply control program (not shown). Specifically, the processor 17 feedback-controls the power supplied to the power receiving side by outputting the control signal (first control signal) S1 to the terminal FB2 of the control circuit 11. Further, the processor 17 outputs a control signal (second control signal) S2 to the base of the transistor Q5 of the initial voltage setting release circuit 15 to turn on the transistor Q5 and set the initial drive control signal Ss to 0V. Further, the processor 17 outputs a control signal (third control signal) S3 to the terminal SD to shut down the control circuit 11.
The processor 17 acquires operation information from an operation unit 19 that includes an operation switch, a touch panel, or the like, which is a host system of the power supply apparatus 1. The processor 17 transmits the operation information acquired from the operation unit 19 to the power receiving device 2 via the wireless unit 16. As a result, the user can operate the load 29. The load 29 is, for example, LED (light emitting diode) illumination.
Further, the processor 17 outputs an alarm to the notification unit 10 that includes a liquid crystal display, a speaker, and the like, which are higher-level systems of the power supply apparatus 1. Thereby, the user can be notified of an error related to wireless power feeding.

  The wireless module M1 operates by being supplied with power of a drive voltage V1 (for example, 3.3 V) from the step-down circuit Re1. The step-down circuit Re1 is an element that is supplied with the power of the driving voltage V1 when the DC voltage Vdc is applied.

  The power receiving device 2 on the power receiving side includes a resonance circuit 21, a rectifier circuit 22, a DC / DC converter (DC conversion circuit; an example of a load) 23, a voltage dividing circuit 24, a wireless module M2, and a step-down circuit Re2. .

The resonance circuit 21 is an LC resonance circuit in which a power receiving coil L2 and a resonance capacitor C1 are connected in parallel. The resonance circuit 21 wirelessly receives power from the power supply coil L1 of the power supply apparatus 1 and generates a resonance voltage.
The rectifier circuit 22 includes a diode bridge DB that rectifies input alternating current into direct current, and a smoothing capacitor C2 that smoothes the rectified voltage. As a result, the electric power of the rectified voltage Va is output and supplied to the DC / DC converter 23, the voltage dividing circuit 24, and the step-down circuit Re2. The secondary power supply unit 28 includes a resonance circuit 21 and a rectifier circuit 22.

The wireless module M2 includes, for example, a wireless unit 26 compliant with Bluetooth (registered trademark) Low Energy and a processor 27. The wireless module M2 operates by being supplied with power of a driving voltage V2 (for example, 3.3V) from the step-down circuit Re2.
The wireless unit 26 (second wireless unit) has a function of transmitting and receiving signals to and from the power supply apparatus 1 via a wireless communication path. The processor 27 (second processor) is, for example, a microcomputer including a storage unit and a processing device, and controls the DC / DC converter 23 by executing a power reception control program (not shown). Further, the processor 27 measures the detection voltage V <b> 3 to generate rectified voltage information, and transmits the rectified voltage information to the power supply apparatus 1 by the wireless unit 26. Further, the processor 27 outputs a control signal S4 to the DC / DC converter 23 to start or stop the DC / DC converter 23.
The processor 27 further receives the operation information input from the operation unit 19 of the power supply apparatus 1 via the wireless unit 26 and controls the DC / DC converter 23 and the load 29 based on the operation information.

The DC / DC converter 23 is a circuit that converts the power of the second predetermined voltage Va2 (for example, 12V) from the secondary-side power supply unit 28 into power of another output voltage Vout. The load 29 is driven by the output voltage Vout of the DC / DC converter 23. The DC / DC converter 23 operates so that the output voltage Vout becomes constant even when the second predetermined voltage Va2 varies. Therefore, the load 29 can be operated stably. The DC / DC converter 23 and the load 29 correspond to the load unit 25 in the power receiving device 2. The DC / DC converter 23 is activated or stopped by a control signal (fourth control signal) S4 output from the wireless module M2.
The voltage dividing circuit 24 includes voltage dividing resistors R3 and R4, and applies a detection voltage V3 obtained by dividing the rectified voltage Va to the processor 27 of the wireless module M2.

  The wireless module M2 operates by being supplied with power of a drive voltage V2 (for example, 3.3V) from the step-down circuit Re2. The step-down circuit Re2 is an element to which the rectified voltage Va is applied and supplies power of the driving voltage V2, and here the power is supplied to the wireless module M2.

FIG. 2 is a configuration diagram of the control circuit 11.
The control circuit 11 includes a step-down circuit 111, operational amplifiers 112 and 113, a comparator 114, a logic circuit 115, and an oscillation circuit 116. The control circuit 11 includes a power supply terminal VDC, a ground terminal GND, a constant voltage terminal VREG that outputs a constant voltage Vreg, input-side terminals FB1, FB2 and a terminal SD, and output-side terminals G1, G2, G3, and G4. , Including.
A DC voltage Vdc is applied to the power supply terminal VDC, and the ground terminal GND is connected to the ground.

  The step-down circuit 111 is a circuit that generates a constant voltage Vreg. For example, a regulator is connected to the power supply terminal VDC and the ground terminal GND, and outputs the constant voltage Vreg generated from the DC voltage Vdc to the constant voltage terminal VREG.

The operational amplifier 112, the resistor R7, and the capacitor C5 constitute an integrating circuit. One end of the resistor R7 is connected to the inverting input terminal of the operational amplifier 112 via the terminal FB1. One end of the capacitor C5 is connected to the inverting input terminal of the operational amplifier 112 via the terminal FB1, and the other end is connected to the output terminal of the operational amplifier 112. The reference voltage Vref1 is applied to the non-inverting input terminal of the operational amplifier 112.
When the initial drive control signal Ss is input to the other end of the resistor R7, the integration circuit outputs an output signal SsC obtained by integrating the potential difference between the reference voltage Vref1 and the initial drive control signal Ss. This integration circuit controls with an integration time constant τ _s so that the initial drive control signal Ss becomes equal to the reference voltage Vref1. The initial drive control signal Ss is input from the initial voltage setting circuit 14 of the initial voltage control circuit 13.

The operational amplifier 113, the resistor R6, and the capacitor C4 constitute an integration circuit. One end of the resistor R6 is connected to the inverting input terminal of the operational amplifier 113 through the terminal FB2. One end of the capacitor C4 is connected to the inverting input terminal of the operational amplifier 113 via the terminal FB2, and the other end is connected to the output terminal of the operational amplifier 113. A reference voltage Vref2 is applied to the non-inverting input terminal of the operational amplifier 113.
When the control signal S1 is input to the other end of the resistor R6, this integrating circuit outputs an output signal S1C obtained by integrating the potential difference between the reference voltage Vref2 and the control signal S1. This integration circuit controls with an integration time constant τ ₁ so that the control signal S1 becomes equal to the reference voltage Vref2. The control signal S1 is input from the processor 17 of the wireless module M1. The operational amplifiers 112 and 113 are collector outputs, and their respective output terminals are connected.

  The output terminal of these operational amplifiers 112 and 113 is connected to the inverting input terminal of the comparator 114, and the lower one of the output signal SsC and the output signal S1C is input. The triangular wave signal St of the oscillation circuit 116 is input to the non-inverting input terminal of the comparator 114. Thereby, an on-duty pulse signal corresponding to the voltage applied to the inverting input terminal can be generated.

In the logic circuit 115, the output terminal of the comparator 114, the triangular wave signal St, and the terminal SD are connected to the input side, and the output terminal of the gate signal is connected to the output side. The logic circuit 115 generates gate signals G1 and G2 and gate signals G3 and G4 from the upper limit peak and lower limit peak of the triangular wave signal St and the falling edge of the pulse signal input from the comparator 114, respectively. When the control signal S3 is input to the terminal SD from the processor 17 of the wireless module M1, the logic circuit 115 stops the output operation of the gate signals G1 to G4.
The oscillation circuit 116 oscillates by being connected to the resistor R5 and the capacitor C3, and outputs a triangular wave.

FIG. 3 is a block diagram showing the wireless power transmission system S.
The wireless power transmission system S shown in FIG. 3 schematically shows each part shown in FIG. The wireless power transmission system S includes a power feeding device 1 and a power receiving device 2.
The power supply apparatus 1 includes a DC power supply 18, an operational amplifier 113, a logic circuit 115, an inverter circuit 12, a power supply coil L 1, a wireless module M 1, a step-down circuit Re 1, an operation unit 19, and a notification unit 10. The wireless module M1 is described as “BLE module”. The processor 17 may include an input / output circuit 171 and a D / A converter 172.

The DC power supply 18 applies a DC voltage Vdc to the step-down circuit Re1, the inverter circuit 12, the operation unit 19, and the notification unit 10. The step-down circuit Re1 applies a drive voltage V1 to the wireless module M1.
The wireless module M1 includes a processor 17, a wireless unit 16, an input / output circuit 171, and a D / A converter 172. The processor 17 performs overall control of the wireless module M1. The input / output circuit 171 acquires operation information from the operation unit 19 and outputs an alarm to the notification unit 10. The D / A converter 172 outputs an analog control signal S 1 to the operational amplifier 113.

The power receiving device 2 includes a power receiving coil L2, a rectifier circuit 22, a voltage dividing circuit 24, a wireless module M2, a step-down circuit Re2, and a load unit 25. The wireless module M2 is described as “BLE module”. The rectifying circuit 22 supplies the rectified voltage Va to the voltage dividing circuit 24, the step-down circuit Re2, and the load unit 25. The step-down circuit Re2 supplies a drive voltage V2 to the wireless module M2.
The wireless module M2 includes a processor 27, a wireless unit 26, an input / output circuit 271, an A / D converter 272, and a threshold table 273. The threshold value table 273 is a table stored in, for example, an EEPROM (Electrically Erasable Programmable Read Only Memory). This threshold table 273 stores correspondences between operation information and changes on the power receiving side, whether or not load fluctuations occur, and thresholds of fluctuation counters during load fluctuations. Here, the load fluctuation means that the rectified voltage fluctuates as the load 29 is driven. The voltage dividing circuit 24 is a voltage dividing resistor that divides the rectified voltage Va. The voltage dividing circuit 24 outputs a detection voltage V3 obtained by dividing the rectified voltage Va to the A / D converter 272 of the wireless module M2. The processor 27 may include an input / output circuit 271 and an A / D converter 272.

<< Operation of Wireless Power Transmission System S >>
The inverter circuit 12 of the power feeding device 1 drives the power feeding coil L1. The power receiving device 2 generates power in the power receiving coil L2 by electromagnetic induction. This electric power becomes a rectified voltage Va rectified by the rectifier circuit 22, is then divided by the voltage divider circuit 24 to become a detection voltage V 3, and is periodically measured by the A / D converter 272. The processor 27 of the power receiving device 2 transmits the detection voltage V <b> 3 measured by the A / D converter 272 to the power feeding device 1 by the wireless unit 26.

  The processor 17 of the power supply apparatus 1 converts the rectified voltage value included in the communication data received via the wireless unit 16 into a control signal S1 that is an analog voltage by the D / A converter 172. The D / A converter 172 continues to output the analog voltage based on the immediately previous rectified voltage value to the operational amplifier 113 until the communication data including the new rectified voltage value is received. The operational amplifier 113 outputs an output signal S1C obtained by integrating the input analog voltage to the logic circuit 115 via a comparison unit with a triangular wave (not shown). The logic circuit 115 drives the inverter circuit 12 with a duty corresponding to the output signal S1C. The wireless power transmission system S is a feedback system that controls the rectified voltage Va of the power receiving device 2 to be stabilized at a voltage of 12 V (target value) by controlling in this way.

The processor 17 of the power supply apparatus 1 acquires the operation information input from the operation unit 19 via the input / output circuit 171 and transmits it via the wireless unit 16. The processor 27 of the power receiving device 2 controls the load unit 25 by receiving the operation information through the wireless unit 26.
The processor 17 of the power supply apparatus 1 stops the inverter circuit 12 for the protection operation when the rectified voltage value is out of a predetermined voltage range (for example, 12V ± 10%) for a predetermined period, and informs the notification unit 10 Output an alarm.

4 and 5 are flowcharts showing processing of the power receiving device 2.
When the processor 27 of the power receiving apparatus 2 is activated, the processing illustrated in FIGS. 4 and 5 is started.
When the cycle timer is completed (step S10 → Yes), the processor 27 acquires A / D conversion data obtained by digitally converting the detection voltage V3 from the A / D converter 272, and further acquires a variation flag (step S11). . The periodic timer of this embodiment is completed every 7.5 milliseconds. In FIG. 4, the A / D converter 272 is abbreviated as “ADC”, and the A / D conversion data is abbreviated as “ADC data”. The fluctuation flag (an example of fluctuation information) is a 1-bit flag indicating whether or not the fluctuation of the rectified voltage value is expected.
The processor 27 generates rectified voltage value information from the A / D conversion data, creates transmission data from the rectified voltage value and the fluctuation flag (step S12), and transmits the data via the wireless unit 26 (step S13). Thereafter, the processor 27 proceeds to the process of step S14. This cycle timer determines a cycle in which the power receiving device 2 transmits transmission data including a rectified voltage value and a fluctuation flag to the power feeding device 1.
In step S10, if the cycle timer has not been completed (step S10 → No), the processor 27 proceeds to the process of step S14.

In step S14, if the processor 27 receives communication data including operation information of the load unit 25 from the power supply apparatus 1 (Yes), the processor 27 controls the load unit 25 according to the operation information (step S15). Then, the processor 27 refers to the threshold value table 273 shown in FIG. 6 and determines whether or not an operation based on this operation information causes a load fluctuation (step S16). Processor 27, if the operation by the operation information to generate a load change (step S16 → Yes), 1 is set to the variation flag (step S17), and sets the threshold value H ₁ variation counter (step S18). Thereafter, the processor 27 proceeds to the process of step S19. The fluctuation counter sets a period until the fluctuation flag is cleared.

If the operation based on the operation information does not cause a load change (step S16 → No), the processor 27 proceeds to the process of step S19. The operation information that causes the load fluctuation refers to, for example, a voltage drop when the load 29 is an LED (Light Emitting Diode) or a voltage kickback when the load 29 is off. The period of load fluctuation due to operation varies depending on the configuration of the power receiving device 2. Therefore, processor 27 of the power receiving device 2 of this embodiment sets the threshold value H ₁ variation counter in accordance with the prediction of the load change.
In step S14, if the processor 27 has not received the communication data including the operation information of the load unit 25 (No), the process proceeds to step S19.

In step S19, the processor 27 refers to the threshold value table 273 shown in FIG. 6 and determines whether or not a load fluctuation occurs due to the reason on the power receiving side. Processor 27, if load fluctuation caused by the reason of the power receiving side (step S19 → Yes), 1 is set to the variation flag (step S20), and sets the threshold value H ₁ variation counter (step S21). Thereafter, the processor 27 proceeds to the process of step S22. In step S19, the processor 27 proceeds to the process of step S22 if no load change occurs for the reason of the power receiving side (No). The load fluctuation due to the reason on the power receiving side occurs, for example, when a switch for turning on / off the load 29 is provided on the power receiving side or when the load 29 is turned on / off by a timer.
In addition, even if it is the load fluctuation | variation which the power receiving apparatus 2 anticipates, when carrying out slow start of LED load, for example, a voltage drop will generate | occur | produce over about 1 second. Therefore, in order to prevent the voltage from being monitored over a long period of time, the processor 27 does not set 1 to the fluctuation flag.

In step S22, the processor 27 adds 1 to the fluctuation counter if the fluctuation flag is set to 1 (Yes) (step S23). If the variation flag is cleared (step S22 → No), the processor 27 returns to the process of step S10.
Further, when the variation counter reaches the threshold value H ₁ and the counting is completed (step S24 → Yes), the processor 27 clears (initializes) this variation counter with 0 (step S25). Thereafter, the processor 27 clears the variation flag (step S26), and returns to the process of step S10. Processor 27 in step S24 is not the change counter reaches the threshold value H _1, if not counting completed (No), the process returns to step S10.

In the present embodiment, a variation flag (an example of variation information) is added to communication data of a rectified voltage value wirelessly transmitted from the power receiving device 2 to the power feeding device 1. The fluctuation flag is set when the voltage on the power receiving side fluctuates due to operation data wirelessly transmitted from the power feeding apparatus 1 to the power receiving apparatus 2 or an expected load fluctuation due to a change on the power receiving apparatus 2 side. The operation data refers to, for example, load on / off, change in load drive state, and the like. The change on the power receiving device 2 side refers to, for example, autonomous load on / off by the host system of the power receiving device 2 or a change in the driving state of the autonomous load. This variation flag is cleared when a predetermined time has elapsed. The power receiving device 2 determines a period during which the variation flag is set according to operation data or a change on the power receiving device 2 side.
When the power receiving apparatus 2 has an unexpected load fluctuation, the fluctuation flag is cleared. The load fluctuations unexpected by the power receiving apparatus 2 are, for example, power supply voltage fluctuations on the power feeding apparatus 1 side, fluctuations in the interval between the power receiving coil L2 and the power feeding coil L1, and the like. Therefore, the power receiving apparatus 2 can indicate to the power feeding apparatus 1 whether or not the load fluctuation and the fluctuation period are expected by the fluctuation flag.

FIG. 6 is a diagram showing a threshold value table 273 that stores the correspondence between the operation on the power feeding side or the change on the power receiving side and the threshold value of the variation counter.
The threshold table 273 includes a power supply side operation / power reception side change column, a load fluctuation occurrence column, and a threshold column. The power supply side operation / power reception side change column indicates an operation on the power supply side or a change on the power reception side. The load fluctuation occurrence column indicates whether or not a load fluctuation occurs. The threshold value column indicates the threshold value of the fluctuation counter when the load fluctuates.
When the operation on the power feeding side or the change on the power receiving side is ON of the LED power source (load 29), load fluctuation occurs, and the threshold value of the fluctuation counter at that time is 12. That is, when the operation on the power supply side is turning on the LED power source, the fluctuation flag is set for 90 milliseconds.
When the operation on the power supply side or the change on the power reception side is the LED power supply off, load fluctuation occurs, and the threshold value of the fluctuation counter at that time is 10. That is, when the operation on the power supply side is turning off the LED power source, the fluctuation flag is set for 75 milliseconds.

When the operation on the power feeding side or the change on the power receiving side is dimming and the light quantity is + 10%, load fluctuation occurs, and the threshold value of the fluctuation counter at that time is 7. That is, when the operation on the power supply side is dimming of the light amount + 10%, the variation flag is set for 52.5 milliseconds.
When the operation on the power feeding side or the change on the power receiving side is dimming and the light quantity is −10%, load fluctuation occurs, and the threshold value of the fluctuation counter at that time is 5. That is, when the operation on the power feeding side is dimming with a light amount of −10%, the fluctuation flag is set for 37.5 milliseconds.
When the operation on the power feeding side or the change on the power receiving side is toning, load fluctuation does not occur. That is, when the operation on the power supply side is toning, the variation flag remains cleared.

When the operation on the power feeding side or the change on the power receiving side is LED slow start, load fluctuation occurs over a relatively long period. In order to prevent the voltage from being unable to be monitored over a long period of time as described above, the load fluctuation occurrence column is “No”. That is, when the operation on the power supply side is LED slow start, the variation flag remains cleared. In this case, the processor 17 on the power supply side detects an abnormality by using an out-of-range counter or an out-of-range enlargement counter described later.
The processor 27 on the power receiving side controls the load 29 according to the operation information on the power feeding apparatus 1 side. Based on the threshold value table 273, the processor 27 can set the variation information over a predetermined period when a load variation due to the control of the load 29 is predicted.

7 and 8 are flowcharts showing the processing of the power supply apparatus 1.
When the processor 17 of the power supply apparatus 1 is activated, the processes shown in FIGS. 7 and 8 are started.
If the communication data is received via the wireless unit 16 (step S30 → Yes), the processor 17 acquires the rectified voltage value and the fluctuation flag from the communication data (step S31). Furthermore, the processor 17 sets the rectified voltage value in the D / A converter 172 (step S32), and proceeds to the process of step S33. The communication data is transmitted from the power receiving device 2 at a predetermined cycle.
If the processor 17 does not receive the communication data via the wireless unit 16 in step S30 (No), the processor 17 proceeds to the process of step S33.

In step S33, if the operation unit 19 detects an operation instruction (Yes), the processor 27 acquires the operation data (step S34), and creates transmission data from the operation data (step S35). Further, the processor 27 wirelessly transmits this transmission data (step S36), and proceeds to the process of step S37.
In step S33, if the operation unit 19 does not detect an operation instruction (No), the processor 27 proceeds to the process of step S37.

In step S37, the processor 17 determines that the rectified voltage value is out of the predetermined voltage range (12V ± 10%) and the difference between the rectified voltage value and the target value (12V) continues to increase (Yes). The outside enlargement counter is incremented by 1 (step S38). Further, when the out-of-range enlargement counter reaches the threshold value H ₃ and is completed (step S39 → Yes), the processor 17 sets the alarm flag to 1 (step S40), and proceeds to the processing of step S42. . As a result, the processor 17 can stop the inverter circuit 12 as a protective operation when the difference between the rectified voltage value and the feedback target value (12 V) continues to increase over a predetermined period. As described above, an example in which the out-of-range enlargement counter reaches the threshold value H ₃ is shown in FIG.
Processor 17 in step S39, if out of range expansion counter has not reached the threshold value H ₃ (No), the process proceeds to step S42.
In step S37, if the rectified voltage value is outside the predetermined voltage range and the difference between the rectified voltage value and the target value has not continued to expand (No), the processor 17 clears the out-of-range expansion counter (step S41). The process proceeds to step S42.

In step S42, if the alarm flag is set to 1 (Yes), the processor 17 proceeds to the process of step S49. Next, in step S43, when the variation flag is set to 1 (Yes), the processor 17 proceeds to the process of step S49.
In step S43, if 1 is not set in the variation flag (No), the processor 17 proceeds to the process of step S44 and determines whether or not the rectified voltage value is outside the range of the predetermined voltage.

In step S44, if the rectified voltage value is out of the predetermined voltage range (Yes), the processor 17 adds 1 to the out-of-range counter (step S45). Further, when the out-of-range counter reaches the threshold value H ₂ and is completed (step S47 → Yes), the processor 17 sets the alarm flag to 1 (step S48), and proceeds to the process of step S49. Thereby, the processor 17 can stop the inverter circuit 12 as a protection operation.
An example in which the out-of-range counter reaches the threshold value H ₂ is shown in FIG.
Processor 17 in step S47, if out of range counter has not reached the threshold value H ₂ (No), the process proceeds to step S49.
In step S44, if the rectified voltage value is not outside the predetermined voltage range (No), the processor 17 clears the out-of-range counter (step S46), and proceeds to the process of step S49.

In step S49, if the alarm flag is set to 1 (Yes), the processor 17 stops the inverter circuit 12 as a protection operation and stops wireless power feeding (step S50). Furthermore, the processor 17 clears the out-of-range counter and the out-of-range enlargement counter (step S51), and outputs an alarm (step S52), and returns to the processing of step S30. As a result, the processor 17 can stop the inverter circuit 12 as a protective operation when the fluctuation flag is cleared and the rectified voltage value is out of the predetermined voltage range for a predetermined period.
In step S49, if the alarm flag is not set to 1 (No), the processor 17 returns to the process of step S30 and continues to drive the inverter circuit 12.

  The wireless unit 26 of the power supply apparatus 1 receives the rectified voltage value and the fluctuation flag every communication cycle. When the fluctuation flag is set, the power feeding device 1 does not perform the protection operation even if the rectified voltage value falls outside the predetermined voltage range, and continues to drive the inverter circuit 12. However, if the fluctuation flag is cleared and the rectified voltage value is out of the predetermined voltage range for a predetermined period, the power feeding device 1 stops the inverter circuit 12 for the protection operation, and the host system An alarm is output to a certain notification unit 10. As a result, the power feeding device 1 stops the wireless power feeding as a protection operation when a voltage fluctuation that is not expected by the power receiving device 2 and does not stop the wireless power feeding when the voltage fluctuation expected by the power receiving device 2 occurs. realizable.

  When the rectified voltage is out of the predetermined voltage range and the difference from the target value continues to increase, the power supply device 1 adds an out-of-range expansion counter for each period timer. Upon completion of the out-of-range enlargement counter set in advance by the user, the power supply device 1 stops the inverter circuit 12 for protection operation, stops wireless power supply, and outputs an alarm to the notification unit 10 that is a host system. Thereby, wireless power feeding can be stopped at the time of an abnormality in which the voltage continues to change in a direction in which the difference from the target value of the feedback control increases.

  In the timing charts shown in FIGS. 9 to 11, the alarm flag, out-of-range expansion counter, out-of-range counter, variation counter, variation flag, and rectified voltage value are shown in order from the top. Among these, the fluctuation flag and the rectified voltage value are included in transmission data transmitted from the power receiving device 2 to the power feeding device 1. The fluctuation counter is internal information managed by the processor 27 of the power receiving device 2. The alarm flag, the out-of-range enlargement counter, and the out-of-range counter are internal information managed by the processor 17 of the power supply apparatus 1.

FIG. 9 is a timing chart showing normal operation.
At time t ₁ , the operation unit 19 of the power feeding device 1 is operated. This operation is an operation of turning on the load unit 25, for example. Thereby, the processor 27 of the power receiving apparatus 2 sets the variation flag to 1, and starts counting of the variation counter.

At time t ₂ , the rectified voltage Va is outside the predetermined range of 12V ± 10% following the previous cycle, and the difference from the target value of 12V is larger than the previous cycle. The processor 17 starts counting the out-of-range enlargement counter.
At time t ₃ , the rectified voltage Va is out of the predetermined voltage range, but since the difference from the target value is decreasing compared to the previous cycle, the processor 17 clears the out-of-range expansion counter.
At time t _4, out of the range rectified voltage Va reaches a predetermined voltage, and the difference between the target value than the period of the one before is expanding, the processor 17 starts to count the range larger counter.
At time t ₅ , the rectified voltage Va is out of the predetermined voltage range, but since the difference from the target value is decreasing compared to the previous period, the out-of-range expansion counter is cleared.

At time t ₆ , the processor 27 of the power receiving device 2 completes the counting of the variation counter and clears the variation flag. A period P ₁ shown in the figure indicates a period from when the processor 27 of the power receiving apparatus 2 starts counting the fluctuation counter to when this counting is completed. In this period P ₁ , a maximum time is set until the load fluctuation due to the content operated on the load unit 25 at time t ₁ converges and the rectified voltage Va returns to the predetermined voltage range again. The period P ₁ is determined by a combination of the fluctuation counter and the threshold value H ₁ .

At time t ₇ , the rectified voltage Va is out of the predetermined voltage range with the fluctuation flag being cleared, so the processor 17 starts counting the out-of-range counter. At time t ₈ , the rectified voltage Va returns to within the predetermined voltage range, so the processor 17 clears the out-of-range counter. In this way, even if the rectified voltage Va is outside the predetermined range of 12V ± 10%, the processor 17 does not perform the protection operation in a short period when there is no problem in driving the load 29. Thereby, the load 29 (host system) can continue the operation.

FIG. 10 is a timing chart showing a case where 1 is set in the alarm flag when the voltage on the power receiving side is outside the predetermined voltage range.
At time t _10, the operation unit 19 of the power supply apparatus 1 is operated. This operation is an operation of turning on the load unit 25, for example. Thereby, the processor 27 of the power receiving apparatus 2 sets the variation flag to 1, and starts counting of the variation counter.

At time t ₁₁ , the processor 27 of the power receiving device 2 completes the counting of the variation counter and clears the variation flag. At this time, since the rectified voltage Va is out of the predetermined range of 12V ± 10%, the processor 17 starts counting of the out-of-range counter. Thereafter, the rectified voltage Va remains outside the range of the predetermined voltage over a period P _2.
At time t ₁₂ , the rectified voltage Va remains out of the predetermined voltage range, and the out-of-range counter reaches the threshold value H ₂ to complete the count. Therefore, the processor 17 sets the alarm flag to 1 and performs the protection operation. Therefore, wireless power supply is stopped. Thereby, the alerting | reporting part 10 alert | reports an alarm to a user. The period P ₂ is determined by a combination of the out-of-range counter and the threshold value H ₂ .

In FIG. 11, the fluctuation flag is set, the fluctuation counter is counted, the voltage on the power receiving side is out of the predetermined voltage range for a predetermined period or longer, and the difference from the target value increases. It is a timing chart which shows the case where it did. The target value of this embodiment is 12V, and the range of the predetermined voltage is 12V ± 10%.
At time t _20, the operation unit 19 of the power supply apparatus 1 is operated. This operation is an operation of turning on the load unit 25, for example. Thereby, the processor 27 of the power receiving apparatus 2 sets the variation flag to 1, and starts counting of the variation counter.

At time t _21, out of the range the previous cycle continues rectified voltage Va that has been predetermined and 12V ± 10%, and the difference between the target value of 12V than the period immediately preceding is expanding, The processor 17 starts counting the out-of-range enlargement counter. Thereafter, the rectified voltage Va remains out of the range of the predetermined voltage over the period P ₃ , and the difference from the target value continues to increase compared to the previous cycle.
At time t _22, processor 17 counts out of range expansion counter reaches the threshold value H ₃ is completed. When the count of the out-of-range expansion counter is completed, the processor 17 sets an alarm flag to 1 and stops wireless power feeding for the protection operation. Thereby, the alerting | reporting part 10 alert | reports an alarm to a user. The period P ₃ is determined by the combination of the out-of-range expansion counter and the threshold value H ₃ .

(Modification)
The present invention is not limited to the above-described embodiment, and can be modified without departing from the spirit of the present invention. For example, there are the following (a) to (k).
(A) The DC / DC converter 23 is not essential for the power receiving device 2, and the load 29 may be directly connected thereto.
(B) The object to be controlled from the host system of the power supply apparatus 1 is not limited to the DC / DC converter 23, and for example, the load 29 may be directly controlled.
(C) The wireless communication protocol between the power feeding device 1 and the power receiving device 2 is not limited to Bluetooth (registered trademark) Low Energy, and may be Wi-Fi (registered trademark), ZIGBEE (registered trademark), or the like. .
(D) The wireless communication between the power feeding device 1 and the power receiving device 2 is not limited to radio wave communication. If an appropriate wireless communication path can be established, wireless communication such as infrared communication, visible light communication, and ultrasonic communication can be used. There may be, and it is not limited.
(E) The feedback control is not limited to the proportional control (classical control) shown in the above embodiment, and may be classic control such as PI control or PID control, or modern control, and is not limited.
(F) The method of notifying the power supply apparatus 1 of the load fluctuation from the power receiving apparatus 2 is not limited to the 1-bit fluctuation flag. The power receiving device 2 may notify the power supply device 1 of the load variation based on variation information of an arbitrary bit width.
(G) Instead of the integration circuit included in the control circuit 11, integration processing may be performed using a digital signal processor.
(H) The threshold value table 273 may not be stored in the EEPROM or the like, and the threshold value may be changed by data transmission from the host system of the power supply apparatus 1.
(I) The target value is not limited to 12V, and the range of the predetermined voltage is not limited to 12V ± 10%. For example, the range of the predetermined voltage is not limited as long as it includes the target value.
(J) The protection operation is not limited to the stop of the inverter circuit 12 of the power feeding device 1, and the wireless power feeding may be shifted to the idle state by turning off the transistor Q5 of the initial voltage setting release circuit 15.
(K) Before the power feeding device 1 stops wireless power feeding in step S50 of FIG. 8, alarm information is wirelessly transmitted to the power receiving device 2, and the power receiving device 2 turns off the DC / DC converter 23 and from the input / output circuit 271. An alarm may be output to the host system of the power receiving device 2.

S wireless power transmission system 1 power feeding device 10 notification unit 11 control circuit 111 step-down circuit 112, 113 operational amplifier 114 comparator 115 logic circuit 116 oscillation circuit R5 to R7 resistor C3 to C5 capacitor 12 inverter circuit 13 initial voltage control circuit 14 initial voltage setting Circuit 15 Initial voltage setting release circuit M1 Wireless module 16 Wireless unit (an example of a first wireless unit)
17 processor (an example of a first processor)
171 I / O circuit 172 D / A converter 18 DC power supply 19 Operation unit L1 Power supply coil Re1, Re2 Step-down circuit 2 Power receiving device 21 Resonant circuit L2 Power receiving coil C1 Resonant capacitor 22 Rectifier circuit DB Diode bridge C2 Smoothing capacitor 23 DC / DC converter ( DC conversion circuit)
24 voltage divider circuit 25 load section M2 wireless module 26 wireless unit (example of second wireless unit)
27 processor (example of second processor)
271 Input / Output Circuit 272 A / D Converter 28 Secondary Power Supply Unit 29 Load

Claims (7)

A wireless power transmission system including a power feeding device and a power receiving device,
The power supply device
A feeding coil that transmits power wirelessly;
An inverter for driving the feeding coil;
A first wireless unit that wirelessly communicates with the power receiving device;
A first processor for controlling the first wireless unit and the inverter;
With
The power receiving device is:
A resonance circuit that generates a resonance voltage, including a power reception coil and a capacitor that wirelessly receive power from the power supply coil of the power supply device;
A rectifier circuit that rectifies the resonance voltage and outputs a rectified voltage;
A load driven by the rectified voltage;
A second wireless unit that wirelessly communicates with the first wireless unit included in the power supply device;
A second processor for controlling the load and the second wireless unit;
With
The second processor generates rectified voltage value information based on the rectified voltage, and sets or clears fluctuation information indicating that the fluctuation of the rectified voltage value is expected, and Transmitting the information including the rectified voltage value and the fluctuation information to the first wireless unit included in the apparatus;
A wireless power transmission system characterized by that. When the fluctuation information received from the power receiving apparatus is set, the first processor included in the power supply apparatus continues to control the inverter, and the fluctuation information received from the power receiving apparatus is cleared. In the case where the rectified voltage value related to the rectified voltage is out of a predetermined voltage range over a predetermined period, a protective operation is performed.
The wireless power transmission system according to claim 1. The power supply device further includes an operation unit for inputting operation information of the load,
The first processor included in the power supply apparatus transmits operation information input from the operation unit to the second wireless unit by the first wireless unit,
The second processor included in the power receiving apparatus controls the load in accordance with operation information received by the second wireless unit, and determines in advance if the load fluctuation is predicted. Setting the variation information over a specified period of time;
The wireless power transmission system according to claim 1 or 2. The second processor included in the power receiving device sets the variation information over a predetermined period when variation in the load is predicted.
The wireless power transmission system according to claim 1 or 2. The first processor included in the power supply apparatus performs a protective operation when a difference between a rectified voltage value received from the second wireless unit and a feedback target value continues to increase over a predetermined period.
The wireless power transmission system according to any one of claims 1 to 3. The variation information is a 1-bit flag.
The wireless power transmission system according to claim 1, wherein the wireless power transmission system is a wireless power transmission system. A method for protecting a wireless power transmission system including a power feeding device and a power receiving device,
The power supply device
A feeding coil that transmits power wirelessly;
An inverter for driving the feeding coil;
A first wireless unit that wirelessly communicates with the power receiving device;
A first processor for controlling the first wireless unit and the inverter;
With
The power receiving device is:
A resonance circuit that generates a resonance voltage, including a power reception coil and a capacitor that wirelessly receive power from the power supply coil of the power supply device;
A rectifier circuit that rectifies the resonance voltage and outputs a rectified voltage;
A load driven by the rectified voltage;
A second wireless unit that wirelessly communicates with the first wireless unit included in the power supply device;
A second processor for controlling the load and the second wireless unit;
With
The second processor generates rectified voltage value information based on the rectified voltage;
Setting or clearing fluctuation information indicating whether or not the fluctuation of the rectified voltage value is expected;
Transmitting information including the rectified voltage value and the variation information to the first wireless unit included in the power supply device;
Run
When the variation information received by the first processor from the second wireless unit is set, the control of the inverter is continued, and the variation information received from the second wireless unit is not set. And, when the rectified voltage value related to the rectified voltage is out of the predetermined voltage range for a predetermined period, a step of performing a protection operation is executed.
A method for protecting a wireless power transmission system.

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