Contactless power supply system and lighting system

Abstract

The objective of this disclosure is to stabilize the operation of lighting loads. [Solution] The contactless power supply system A1 comprises a power transmission device 1 having a power transmission coil 10, a power supply circuit unit 11, a power transmission side communication unit 14, and a power transmission side control unit 12, and a power receiving device 2 having a power receiving coil 20, a lighting circuit unit 21, an electrical characteristic detection unit 25, and a power receiving side communication unit 23. The lighting circuit unit 21 lights up a lighting load 3 using power received via the power receiving coil 20. The electrical characteristic detection unit 25 detects at least one of the current flowing through the lighting load 3 and the voltage generated in the lighting load 3. The power receiving side communication unit 23 transmits a wireless signal S1 including the detection result of the electrical characteristic detection unit 25. The power supply circuit unit 11 supplies current to the power transmission coil 10. The power transmission side communication unit 14 receives the wireless signal S1. The power transmission side control unit 12 controls the power supply circuit unit 11 based on the detection result of the electrical characteristic detection unit 25 included in the wireless signal S1 received by the power transmission side communication unit 14.

Description

Technical Field

[0004]

[0001] The present disclosure relates to a non-contact power supply system and a lighting system. More specifically, it relates to a non-contact power supply system in which a power receiving device that is non-contact power supplied from a power transmission device lights a lighting load, and a lighting system having the non-contact power supply system and the lighting load.

Background Art

[0002] As a conventional example, a lighting device (lighting system) described in Patent Document 1 is exemplified. The lighting device described in Patent Document 1 (hereinafter referred to as a conventional example) includes a power supply unit and a light emitting unit having a light source that is lit by the supply of power from the power supply unit. The power supply unit includes a primary coil. The light emitting unit includes a secondary coil that electromagnetic induction with the primary coil, and is detachably attached to the power supply unit. The conventional example is configured to be able to supply power from the power supply unit to the light emitting unit by electromagnetic induction between the primary coil and the secondary coil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the conventional example, stabilization of lighting of the light source (lighting load) is desired.

[0005] An object of the present disclosure is to provide a non-contact power supply system and a lighting system capable of stabilizing lighting of a lighting load.

Means for Solving the Problems

[0006] A contactless power supply system according to one aspect of the present disclosure comprises a power transmission device that transmits power in a contactless manner via a power transmission coil, and a power receiving device that receives power in a contactless manner via a power receiving coil. The power receiving device includes the power receiving coil, a lighting circuit unit that lights up a lighting load using the power received via the power receiving coil, an electrical characteristic detection unit that detects at least one of the current flowing through the lighting load and the voltage generated in the lighting load, and a power receiving side communication unit that transmits a wireless signal including the detection result of the electrical characteristic detection unit. The power transmission device includes the power transmission coil, a power supply circuit unit that supplies current to the power transmission coil, a power transmission side communication unit that receives the wireless signal, and a power transmission side control unit that controls the power supply circuit unit based on the detection result included in the wireless signal received by the power transmission side communication unit.

[0007] A lighting system according to one aspect of this disclosure comprises the contactless power supply system and the lighting load. [Effects of the Invention]

[0008] The contactless power supply system and lighting system disclosed herein have the effect of stabilizing the illumination of lighting loads. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram of a contactless power supply system and a lighting system according to an embodiment of the present disclosure. [Figure 2] Figure 2 is a partially abbreviated block diagram showing a modified example 1 of the same contactless power supply system. [Figure 3] Figure 3 is a partially abbreviated block diagram showing a modified example 2 of the same contactless power supply system. [Figure 4] Figure 4 is a perspective view showing a third modified example of the same lighting system. [Modes for carrying out the invention]

[0010] Hereinafter, a contactless power supply system A1 and a lighting system B1 according to embodiments of this disclosure will be described in detail with reference to the drawings. However, the configurations described in the following embodiments are merely examples of this disclosure. This disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of this disclosure can be achieved.

[0011] (1) Overview The contactless power supply system A1 according to this embodiment comprises a power transmission device 1 that transmits power contactlessly via a power transmission coil 10, and a power receiving device 2 that receives power contactlessly via a power receiving coil 20 (see Figure 1).

[0012] Furthermore, the lighting system B1 according to the embodiment comprises a contactless power supply system A1 according to the embodiment and a lighting load 3 (see Figure 1). The lighting load 3 has, for example, one or more LEDs. The LEDs are preferably, for example, white LEDs for illumination. However, the lighting load 3 may have multiple types of LEDs with different light colors, for example, two LEDs of warm white and daylight color. Alternatively, the lighting load 3 may have three or more LEDs, including red LEDs, green LEDs, and blue LEDs.

[0013] The power receiving device 2 includes a power receiving coil 20, a lighting circuit unit 21, an electrical characteristic detection unit 25, and a power receiving side communication unit 23.

[0014] The lighting circuit 21 uses the power received via the power receiving coil 20 to light the lighting load 3.

[0015] The electrical characteristic detection unit 25 detects at least one of the current flowing through the lighting load 3 and the voltage generated in the lighting load 3.

[0016] The receiving-side communication unit 23 transmits a wireless signal S1 that includes the detection result from the electrical characteristic detection unit 25.

[0017] The power transmission device 1 includes a power transmission coil 10, a power supply circuit unit 11, a power transmission side communication unit 14, and a power transmission side control unit 12.

[0018] The power supply circuit unit 11 supplies current to the power transmission coil 10.

[0019] The power transmission side communication unit 14 receives the wireless signal S1.

[0020] The power transmission side control unit 12 controls the power supply circuit unit 11 based on the detection result of the electrical property detection unit 25 included in the wireless signal S1 received by the power transmission side communication unit 14.

[0021] The power supply circuit unit 11 is configured to supply a high-frequency current of about several tens of kHz to several tens of MHz to the power transmission coil 10. When a high-frequency current flows through the power transmission coil 10, a high-frequency magnetic field (magnetic flux) is generated. The power reception coil 20 generates an induced electromotive force by linking with the high-frequency magnetic flux generated by the power transmission coil 10. That is, the non-contact power supply system A1 according to the embodiment can perform non-contact power supply from the power transmission device 1 to the power reception device 2 using electromagnetic induction.

[0022] Here, due to individual differences in the lighting load 3, the positional relationship between the power transmission device 1 and the power reception device 2, etc., there was a possibility that the lighting of the lighting load 3 would become unstable.

[0023] According to the above configuration, the power supply circuit unit 11 can be controlled in response to at least one of the change in the current flowing through the lighting load 3 and the voltage generated in the lighting load 3, and the lighting of the lighting load 3 can be stabilized.

[0024] (2) Details (2-1) Configuration of the non-contact power supply system according to the embodiment The non-contact power supply system A1 according to the embodiment (hereinafter abbreviated as the non-contact power supply system A1) includes a power transmission device 1 that performs non-contact power transmission via a power transmission coil 10 and a power reception device 2 that performs non-contact power reception via a power reception coil 20 (see FIG. 1).

[0025] The power transmission device 1 includes a power transmission coil 10, a power supply circuit unit 11, a power transmission side communication unit 14, and a power transmission side control unit 12.

[0026] The power transmission coil 10 may be a cylindrical coil (solenoid) with a wire wound in a tubular shape, or a coil with a wire wound in a spiral shape, etc.

[0027] The power supply circuit section 11 includes a full-wave rectifier that full-wave rectifies the AC voltage and AC current supplied from the external AC power supply 5, a smoothing capacitor that smooths the pulsating voltage and pulsating current output from the full-wave rectifier, and an inverter circuit that converts the DC voltage and DC current smoothed by the smoothing capacitor into a high-frequency voltage and high-frequency current. The inverter circuit is preferably a half-bridge type inverter circuit with two semiconductor switching elements, or a full-bridge type inverter circuit with four semiconductor switching elements. The inverter circuit is configured to convert the DC voltage and DC current smoothed by the smoothing capacitor into a high-frequency voltage and high-frequency current by switching two or four semiconductor switching elements and apply them to the power transmission coil 10. The frequency of the high-frequency voltage and high-frequency current output from the inverter circuit is preferably in the range of several tens of kHz to several tens of MHz.

[0028] The power transmission control unit 12 primarily consists of a microcontroller. The power transmission control unit 12 is configured to control the power supply circuit unit 11 by having the microcontroller's processor execute a program. In addition, the power transmission control unit 12 may also have a drive circuit (driving integrated circuit) separate from the microcontroller to drive the two or four semiconductor switching elements in the inverter circuit of the power supply circuit unit 11.

[0029] The power transmission control unit 12 controls the power supply circuit unit 11 based on the radio signal (first radio signal) S1 received by the power transmission communication unit 14. The operation of the power transmission control unit 12 based on the first radio signal S1 will be explained in detail in "(2-3) Operation of the contactless power supply system and lighting system".

[0030] Furthermore, the power transmission control unit 12 receives signals transmitted from, for example, the remote controller and provides the power transmission communication unit 14 with data of the instructed dimming level, which is the dimming level corresponding to the command contained in the received signal. The instructed dimming level data is also stored in the memory of the power transmission control unit 12. Here, the dimming level is the ratio of the current value when the lighting load 3 is lit at its rated current value (rated current value) is set to 100%. For example, a dimming level of 50% means a current value that is half of the rated current value.

[0031] The transmitting-side communication unit 14 is configured to transmit and receive wireless signals using electromagnetic waves, including light (visible light or infrared light) and radio waves, as a medium. The transmitting-side communication unit 14 can transmit and receive wireless signals via the transmitting coil 10 by using radio waves with the same frequency as the high-frequency current that the power supply circuit unit 11 flows through the transmitting coil 10 as a medium. Such wireless communication is preferably performed in accordance with a standard called NFC (Near Field Communication).

[0032] The transmitting communication unit 14 receives the first radio signal S1 transmitted by the receiving communication unit 23, which will be described later.

[0033] Furthermore, the power transmission side communication unit 14 transmits a second radio signal S2 which includes data on the instructed dimming level provided by the power transmission side control unit 12.

[0034] The power receiving device 2 includes a power receiving coil 20, a lighting circuit unit 21, an electrical characteristic detection unit 25, a power receiving side control unit 22, and a power receiving side communication unit 23.

[0035] The receiving coil 20 may be a solenoid or a coil with a wire wound in a spiral. However, it is preferable that the receiving coil 20 has the same shape as the transmitting coil 10. The receiving coil 20 generates an induced electromotive force by linking with the high-frequency magnetic flux generated by the transmitting coil 10.

[0036] The lighting circuit section 21 includes, for example, a full-wave rectifier with both ends of the power receiving coil 20 electrically connected to the AC input terminal, a smoothing capacitor electrically connected to the pulsating output terminal of the full-wave rectifier, and a DC conversion circuit with both ends of the smoothing capacitor electrically connected to the input terminal. The DC conversion circuit is composed of, for example, a buck-boost converter (step-up / step-down chopper). The DC conversion circuit steps up or steps down the DC voltage smoothed by the smoothing capacitor and applies it to the lighting load 3.

[0037] The electrical characteristic detection unit 25 includes at least one of a current detection circuit that detects the current (DC current) flowing through the lighting load 3, and a voltage detection circuit that detects the voltage (DC voltage) applied to the lighting load 3.

[0038] The electrical characteristic detection unit 25 detects at least one of the current value flowing through the lighting load 3 and the voltage value applied to the lighting load 3, and outputs it to the power receiving control unit 22.

[0039] The power receiving control unit 22 primarily consists of a microcontroller. The power receiving control unit 22 is configured to control the lighting circuit unit 21 by having the microcontroller's processor execute a program. In addition to the microcontroller, the power receiving control unit 22 may also have a drive circuit (driving integrated circuit) that drives the semiconductor switching elements in the DC conversion circuit of the lighting circuit unit 21.

[0040] The power receiving control unit 22 generates a first wireless signal S1 at predetermined intervals, which includes at least one of the current value flowing through the lighting load 3 and the voltage value applied to the lighting load 3, as detected by the electrical characteristic detection unit 25.

[0041] Furthermore, the power receiving control unit 22 controls the lighting circuit unit 21 according to the instructed dimming level of the lighting load 3 included in the second wireless signal S2 received by the power receiving communication unit 23.

[0042] The receiving-side communication unit 23 is configured to transmit and receive wireless signals using electromagnetic waves, including light (visible light or infrared light) and radio waves, as a medium. The receiving-side communication unit 23 can transmit and receive wireless signals via the transmitting coil 10 by using radio waves with the same frequency as the high-frequency current that the power supply circuit unit 11 flows through the transmitting coil 10 as a medium. Such wireless communication is preferably performed in accordance with a standard called NFC, for example.

[0043] The receiving-side communication unit 23 transmits the first radio signal S1 generated by the receiving-side control unit 22 at predetermined intervals. In other words, the receiving-side communication unit 23 transmits the first radio signal S1 including the detection result of the electrical characteristic detection unit 25.

[0044] Furthermore, the receiving-side communication unit 23 is configured to receive the second radio signal S2 transmitted from the transmitting-side communication unit 14, acquire the instructed dimming level of the lighting load 3 included in the received second radio signal S2, and pass the acquired instructed dimming level of the lighting load 3 to the receiving-side control unit 22.

[0045] (2-2) Configuration of the lighting system according to the embodiment The lighting system B1 according to the embodiment (hereinafter referred to as lighting system B1) comprises the contactless power supply system A1 described above and a lighting load 3.

[0046] The lighting load 3 preferably has LEDs, but may also have other light-emitting elements, such as organic electroluminescent elements or semiconductor laser elements. The lighting load 3 may be configured integrally with the power receiving device 2, or it may be configured separately and detachably from the power receiving device 2. The lighting load 3 emits light (lights up) when a direct current output from the lighting circuit section 21 of the power receiving device 2 flows through it, and the light intensity is adjusted (dimmed) by increasing or decreasing the value of the direct current. Furthermore, if the lighting load 3 has multiple types of LEDs with different light colors, a direct current is individually supplied to each LED of each light color from the lighting circuit section 21 of the power receiving device 2. The color of the illumination light emitted from the lighting load 3 is then adjusted (color-tuned) by changing the ratio of the current values ​​of the direct currents flowing through each LED of each light color.

[0047] (2-3) Operation of the contactless power supply system and lighting system Next, the operation of the contactless power supply system A1 and the lighting system B1 will be explained. As a prerequisite, the power transmission device 1 is installed in a location where it can be powered by an external power source (AC power supply 5), and the power receiving device 2 is installed in a location where it can receive power from the power transmission device 1 at all times or at any time.

[0048] The power transmission control unit 12 of the power transmission device 1 intermittently operates the power supply circuit unit 11 and intermittently transmits wireless signals from the power transmission communication unit 14. The power transmission control unit 12 continues to operate the power supply circuit unit 11 intermittently unless the power transmission communication unit 14 receives a reply wireless signal including an ACK (acknowledgment) from the power receiving communication unit 23 of the power receiving device 2. If the power transmission control unit 14 receives a reply wireless signal including an ACK from the power receiving communication unit 23 of the power receiving device 2, the power transmission control unit 12 operates the power supply circuit unit 11 continuously and starts supplying power to the power receiving device 2. In other words, the contactless power supply system A1 determines whether the power receiving device 2 is located in a place where it can receive power from the power transmission device 1 by sending and receiving wireless signals between the power transmission device 1 and the power receiving device 2, and operates the power supply circuit unit 11 intermittently if it determines that the power receiving device 2 is not located there. As a result, the contactless power supply system A1 can suppress unnecessary power consumption of the power transmission device 1 while preventing malfunctions (such as temperature rise of foreign objects) that occur when foreign objects (conductors) are present near the power transmission coil 10.

[0049] When the power transmission control unit 12 keeps the power supply circuit unit 11 running continuously, a high-frequency current flows through the power transmission coil 10, generating a magnetic flux. The magnetic flux generated in the power transmission coil 10 links with the power receiving coil 20, inducing an electromotive force in the power receiving coil 20, allowing the power receiving device 2 to receive power. The power receiving device 2 uses the power supplied from the power transmission device 1 to light the lighting load 3 using the lighting circuit unit 21.

[0050] Furthermore, the power transmission control unit 12 receives a signal transmitted from the remote controller and provides the power transmission communication unit 14 with data of the instructed dimming level, which is the dimming level corresponding to the command included in the received signal. The power transmission communication unit 14 transmits a second wireless signal S2 that includes the instructed dimming level data provided by the power transmission control unit 12. If the lighting load 3 has multiple types of LEDs with different light colors, the power transmission control unit 12 causes the power transmission communication unit 14 to transmit color adjustment data, including the instructed dimming level for each LED of each light color, via the second wireless signal S2.

[0051] The receiving-side communication unit 23 receives the second radio signal S2 transmitted from the transmitting-side communication unit 14, acquires the data of the instructed dimming level contained in the second radio signal S2, and passes it to the receiving-side control unit 22. The receiving-side control unit 22 controls the lighting circuit unit 21 so that the current value of the DC current supplied to the lighting load 3 matches the instructed dimming level of the received data. Specifically, the receiving-side control unit 22 adjusts the DC current output from the lighting circuit unit 21 by PWM control of the DC conversion circuit of the lighting circuit unit 21 to dim the lighting load 3. In addition, the receiving-side control unit 22 adjusts the color of the illumination light radiated from the lighting load 3 by adjusting the DC current output from the lighting circuit unit 21 for each LED of each light color according to the color adjustment data received by the receiving-side communication unit 23.

[0052] As described above, the contactless power supply system A1 transmits a second wireless signal S2, which includes an instructed dimming level, from the transmitting communication unit 14 to the receiving communication unit 23, and causes the receiving control unit 22 to control the lighting circuit unit 21 according to the instructed dimming level included in the second wireless signal S2. Therefore, the contactless power supply system A1 can dim the lighting load 3 while providing contactless power, thereby improving ease of use.

[0053] Here, the electrical characteristic detection unit 25 detects at least one of the values ​​of the current flowing through the lighting load 3 (receiving side current value) and the voltage applied to the lighting load 3 (receiving side voltage value) while the lighting load 3 is lit at the indicated dimming level, and outputs it to the receiving side control unit 22.

[0054] The power receiving control unit 22 generates a first wireless signal S1 at predetermined intervals, which includes at least one of the power receiving current value and the power receiving voltage value detected by the electrical characteristic detection unit 25.

[0055] The receiving-side communication unit 23 transmits the first radio signal S1 generated by the receiving-side control unit 22 at predetermined intervals.

[0056] The transmitting communication unit 14 receives the first radio signal S1 transmitted by the receiving communication unit 23.

[0057] Here, the memory of the power transmission control unit 12 stores a data table that associates multiple dimming levels, for example, set between 1% and 100%, with the electrical characteristics of the power receiving device 2 when the lighting load 3 is at each dimming level. The electrical characteristics of the power receiving device 2 include at least one of the value of the current flowing through the lighting load 3 and the value of the voltage generated at the lighting load 3. The power transmission control unit 12 controls the power supply circuit unit 11 so that the detection result of the electrical characteristic detection unit 25 included in the first radio signal S1 matches the electrical characteristics of the power receiving device 2 corresponding to the instructed dimming level stored in the memory of the power transmission control unit 12. In other words, the power transmission control unit 12 controls the power supply circuit unit 11 so that the detection result of the electrical characteristic detection unit 25 included in the first radio signal S1 corresponds to the instructed dimming level stored in the memory of the power transmission control unit 12.

[0058] For example, when the electrical characteristic detection unit 25 detects the receiving-side current value, the transmitting-side control unit 12 controls the power supply circuit unit 11 so that the receiving-side current value matches the value of the current flowing to the lighting load 3 corresponding to the indicative dimming level stored in the memory of the transmitting-side control unit 12. Note that "matching the value of the current flowing to the lighting load 3 corresponding to the indicative dimming level" is not limited to the receiving-side current value exactly matching the value of the current flowing to the lighting load 3 corresponding to the indicative dimming level, but also includes the receiving-side current value being within a predetermined range that includes the value of the current flowing to the lighting load 3 corresponding to the indicative dimming level.

[0059] Furthermore, when the electrical characteristic detection unit 25 detects the receiving-side voltage value, the transmitting-side control unit 12 controls the power supply circuit unit 11 so that the receiving-side voltage value matches the voltage value generated at the lighting load 3 corresponding to the indicative dimming level stored in the memory of the transmitting-side control unit 12. Note that "matching the voltage value generated at the lighting load 3 corresponding to the indicative dimming level" is not limited to the receiving-side voltage value exactly matching the voltage value generated at the lighting load 3 corresponding to the indicative dimming level, but also includes the receiving-side voltage value being within a predetermined range that includes the voltage value generated at the lighting load 3 corresponding to the indicative dimming level.

[0060] Furthermore, when the electrical characteristic detection unit 25 detects the receiving-side current value and the receiving-side voltage value, the transmitting-side control unit 12 controls the power supply circuit unit 11 so that the receiving-side current value and the receiving-side voltage value match the current value flowing through the lighting load 3 and the voltage value generated at the lighting load 3 corresponding to the indicative dimming level stored in the memory of the transmitting-side control unit 12. Note that "matching the current value flowing through the lighting load 3 and the voltage value generated at the lighting load 3 corresponding to the indicative dimming level" is not limited to the receiving-side current value and the receiving-side voltage value perfectly matching the current value flowing through the lighting load 3 and the voltage value generated at the lighting load 3 corresponding to the indicative dimming level. In other words, "matching the current value flowing through the lighting load 3 and the voltage value generated at the lighting load 3 corresponding to the indicative dimming level" also includes the receiving-side current value and the receiving-side voltage value falling within a predetermined range including the current value flowing through the lighting load 3 and the voltage value generated at the lighting load 3, respectively.

[0061] More specifically, the power transmission control unit 12 controls the power supply circuit unit 11 to decrease or increase the current flowing through the power transmission coil 10 based on the detection result of the electrical characteristic detection unit 25 included in the first radio signal S1 received by the power transmission communication unit 14. If the detection result of the electrical characteristic detection unit 25 included in the first radio signal S1 matches the electrical characteristics of the power receiving device 2 corresponding to the indicative dimming level stored in the memory of the power transmission control unit 12, the power transmission control unit 12 maintains a constant current flowing through the power transmission coil 10.

[0062] This allows the lighting load 3 to be stably illuminated at the indicated dimming level.

[0063] (2-4) Modifications of contactless power supply systems Next, several modifications of the contactless power supply system A1 and the lighting system B1 will be described. However, the basic configuration of each modification described below is the same as the basic configuration of the embodiment. Therefore, components that are common to or substantially common with the basic configuration of the embodiment will be denoted by the same reference numerals, and their illustration and description will be omitted as appropriate. In the following description, "substantially common configuration" means a configuration that differs slightly in shape, size, etc., but has the same function.

[0064] (2-4-1) Variation 1 The contactless power supply system A1 in Modification Example 1 employs a magnetic resonance method (also called magnetic resonance method), which is a type of non-radiative method similar to the electromagnetic induction method, as a contactless power supply method from the power transmission device 1 to the power receiving device 2.

[0065] In Modification 1, the transmitting coil 10, together with the capacitor 151, constitutes a resonator (hereinafter referred to as the transmitting side resonator 15) (see Figure 2). Also, in Modification 1, the receiving coil 20, together with the capacitor 241, constitutes a resonator (hereinafter referred to as the receiving side resonator 24) (see Figure 2).

[0066] However, the non-contact power supply system A1 of Modified Example 1 can supply power from the power transmission device 1 to the power receiving device 2 without contact by causing the power transmission side resonator 15 and the power receiving side resonator 24 to resonate (magnetic field resonance). Furthermore, since the non-contact power supply system A1 of Modified Example 1 performs non-contact power supply from the power transmission device 1 to the power receiving device 2 using the magnetic field resonance method, it is possible to increase the transmission distance (distance between the power transmission coil 10 and the power receiving coil 20) through non-contact power supply compared to the electromagnetic induction method.

[0067] (2-4-2) Modification example 2 The non-contact power supply system A1 of Modified Example 2 is characterized in that the power transmission device 1 is equipped with multiple power transmission coils 10. In Modified Example 2, the power transmission device 1 may supply high-frequency current from a single power supply circuit unit 11 to multiple power transmission coils 10, or it may be equipped with multiple power supply circuit units 11 that correspond one-to-one with multiple power transmission coils 10.

[0068] As shown in Figure 3, the power transmission device 1 in Modified Example 2 has a plurality (for example, two) of power transmission coils 10A and 10B. The power transmission device 1 in Modified Example 2 is configured to supply high-frequency current to each power transmission coil 10A and 10B from a single power supply circuit unit 11. However, the power transmission device 1 in Modified Example 2 may have three or more power transmission coils 10A, 10B, ... Also, the power transmission device 1 in Modified Example 2 may have a plurality of power supply circuit units 11 that correspond one-to-one with the plurality of power transmission coils 10A and 10B, and may be configured to supply high-frequency current individually to each power transmission coil 10A, 10B, ... from the plurality of power supply circuit units 11.

[0069] However, the non-contact power supply system A1 of the modified example 2 can supply power to two power receiving devices 2 simultaneously from one power transmitting device 1, thereby improving usability. Furthermore, the non-contact power supply system A1 of the modified example 2 can improve usability by increasing the flexibility of the installation location of the power receiving devices 2 by installing multiple power transmitting coils 10A and 10B in different locations.

[0070] (2-4-3) Modification 3 The lighting system B1 of Modification 3 comprises a contactless power supply system A1 and a lighting fixture 6 (see Figure 4). The power transmission device 1 of the contactless power supply system A1 in Modification 3 is installed on the underside of the tabletop 40 of the table 4. However, the multiple (for example, four) power transmission coils 10A, 10B, 10C, and 10D of the power transmission device 1 in Modification 3 are arranged vertically and horizontally with spacing between them on the surface (top) of the tabletop 40 of the table 4.

[0071] The lighting fixture 6 comprises a base 60 that houses the power receiving device 2 and the power receiving coil 20 and is placed on the upper surface of the deck 40, a cylindrical main body 61 that protrudes upward from the base 60, and a lamp body 62 that is rotatably connected to the tip (upper end) of the main body 61. In other words, the lighting fixture 6 is a so-called LED desk lamp. The power receiving coil 20 is provided on the lower surface of the base 60. The lighting load 3 is provided on the lamp body 62.

[0072] In Modification 3, the power transmission device 1 supplies power to the power receiving device 2 via one of the multiple power transmission coils 10A, 10B, 10C, and 10D, which overlaps with the base 60 of the lighting fixture 6. In other words, the lighting system B1 of Modification 3 can be used by placing the lighting fixture 6 at any location on the upper surface of the deck 40 (where the multiple power transmission coils 10A, 10B, 10C, and 10D are located), so there is no need to provide a power cord to the lighting fixture 6, and the installation location can be freely selected, improving usability.

[0073] (3) Summary A non-contact power supply system (A1) according to a first aspect of the present disclosure comprises a power transmission device (1) that transmits power non-contact via a power transmission coil (10) and a power receiving device (2) that receives power non-contact via a power receiving coil (20). The power receiving device (2) includes a power receiving coil (20), a lighting circuit unit (21), an electrical characteristic detection unit (25), and a power receiving side communication unit (23). The lighting circuit unit (21) lights up a lighting load (3) using the power received via the power receiving coil (20). The electrical characteristic detection unit (25) detects at least one of the current flowing through the lighting load (3) and the voltage generated in the lighting load (3). The power receiving side communication unit (23) transmits a wireless signal (S1) including the detection result of the electrical characteristic detection unit (25). The power transmission device (1) includes a power transmission coil (10), a power supply circuit unit (11), a power transmission side communication unit (14), and a power transmission side control unit (12). The power supply circuit unit (11) supplies current to the power transmission coil (10). The power transmission side communication unit (14) receives a radio signal (S1). The power transmission side control unit (12) controls the power supply circuit unit (11) based on the detection result of the electrical characteristic detection unit (25) included in the radio signal (S1) received by the power transmission side communication unit (14).

[0074] According to this embodiment, the power supply circuit (11) can be controlled in response to changes in at least one of the current flowing through the lighting load (3) and the voltage generated across the lighting load (3), thereby stabilizing the lighting of the lighting load (3).

[0075] In a contactless power supply system (A1) according to a second aspect of the present disclosure, in the first aspect, the power transmission side control unit (12) controls the power supply circuit unit (11) to decrease or increase the current flowing through the power transmission coil (10) based on the detection result of the electrical characteristic detection unit (25) included in the wireless signal (S1) received by the power transmission side communication unit (14).

[0076] According to this embodiment, the lighting of the lighting load (3) can be stabilized by reducing or increasing the current flowing through the power transmission coil (10) in response to a change in at least one of the current flowing through the lighting load (3) and the voltage generated across the lighting load (3).

[0077] In a contactless power supply system (A1) according to a third aspect of the present disclosure, in the first or second embodiment, the transmitting communication unit (14) transmits a second radio signal (S2) which includes the dimming level of a lighting load (3), in contrast to a first radio signal (S1), which is a radio signal (S1). The receiving communication unit (23) receives the second radio signal (S2). The receiving device (2) further includes a receiving control unit (22) which controls the lighting circuit unit (21) according to the dimming level included in the second radio signal (S2) received by the receiving communication unit (23).

[0078] According to this embodiment, the lighting load (3) can be dimmed while providing contactless power, thereby improving ease of use.

[0079] In a non-contact power supply system (A1) according to a fourth aspect of the present disclosure, in a third aspect, the power transmission side control unit (12) controls the power supply circuit unit (11) such that the detection result of the electrical characteristic detection unit (25) included in the first radio signal (S1) corresponds to the dimming level included in the second radio signal (S2).

[0080] According to this embodiment, the lighting load (3) can be stably illuminated at the dimming level included in the second wireless signal (S2).

[0081] In a non-contact power supply system (A1) according to a fifth aspect of this disclosure, in any of the first to fourth embodiments, the power transmission device (1) further comprises a resonator (power transmission side resonator 15) including a power transmission coil (10). The power receiving device (2) further comprises a resonator (power receiving side resonator 24) including a power receiving coil (20).

[0082] According to this embodiment, the contactless power supply system (A1) performs contactless power supply from the power transmission device (1) to the power receiving device (2) using a magnetic field resonance method, thereby increasing the transmission distance by contactless power supply compared to the electromagnetic induction method.

[0083] A lighting system (B1) according to a sixth aspect of this disclosure comprises a non-contact power supply system (A1) according to any of the first to fifth aspects and a lighting load (3).

[0084] According to this embodiment, the power supply circuit (11) can be controlled in response to changes in at least one of the current flowing through the power receiving coil (20) and the voltage generated in the power receiving coil (20), thereby stabilizing the lighting of the lighting load (3). [Explanation of Symbols]

[0085] A1 Contactless power supply system B1 Lighting System 1. Power transmission equipment 2. Power receiving device 3. Lighting load 10 Power transmission coil 11 Power supply circuit section 12 Power transmission side control unit 14. Transmission side communication unit 15 Power transmission side resonator (resonator) 20 Power receiving coil 21 Lighting circuit section 22 Power receiving side control unit 23. Receiving side communication unit 24. Receiving side resonator (resonator) 25 Electrical characteristic detection unit S1 Radio signal (first radio signal) S2 2nd radio signal

Claims

1. A power transmission device that transmits power without contact via a power transmission coil, A power receiving device that receives power non-contact via a power receiving coil, Equipped with, The power receiving device is The aforementioned power receiving coil, A lighting circuit unit that uses the power received via the aforementioned power receiving coil to light up a lighting load, An electrical characteristic detection unit that detects at least one of the current flowing through the lighting load and the voltage generated in the lighting load, A receiving-side communication unit that transmits a wireless signal including the detection result of the electrical characteristic detection unit, It has, The aforementioned power transmission device is The aforementioned power transmission coil, A power supply circuit section that supplies current to the aforementioned power transmission coil, A power transmission side communication unit that receives the aforementioned wireless signal, Based on the detection result included in the wireless signal received by the power transmission side communication unit, the power transmission side control unit controls the power supply circuit unit, Having, Contactless power supply system.

2. The power transmission side control unit controls the power supply circuit unit to decrease or increase the current flowing through the power transmission coil based on the detection result included in the wireless signal received by the power transmission side communication unit. The contactless power supply system according to claim 1.

3. The power transmission side communication unit transmits a second radio signal, which includes the dimming level of the lighting load, unlike the first radio signal which is a wireless signal. The receiving side communication unit receives the second wireless signal, The power receiving device further comprises a power receiving control unit that controls the lighting circuit unit according to the dimming level included in the second wireless signal received by the power receiving communication unit. The contactless power supply system according to claim 1 or 2.

4. The power transmission side control unit controls the power supply circuit unit so that the detection result included in the first wireless signal corresponds to the dimming level. The contactless power supply system according to claim 3.

5. The power transmission device further includes a resonator containing the power transmission coil, The power receiving device further comprises a resonator including the power receiving coil. The contactless power supply system according to claim 1 or 2.

6. A contactless power supply system according to claim 1 or 2, The aforementioned lighting load and, Equipped with, Lighting system.

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