Power supply device, power supply method, and program

Abstract

It enables appropriate power supply based on the detected temperature. [Solution] The power transmission circuit 160 supplies power to the power receiving device 200. The temperature sensor 140 detects the temperature of a predetermined part of the power supply device 100. The control circuit 170 controls the power supply to the power receiving device 200 by the power transmission circuit 160 based on the detected temperature, which is the temperature detected by the temperature sensor 140, and the reference temperature. If the control circuit 170 has elapsed for more than one specified time since the end of the previous power supply at the start of power supply, and the rate of change of the detected temperature during the specified period immediately before the start of power supply is within the reference value, the control circuit 170 updates the reference temperature to the detected temperature at the start of power supply.

Description

Technical Field

[0001] The present disclosure relates to a power supply device, a power supply method, and a program.

Background Art

[0002] There is known a power supply device that supplies power to a power receiving device incorporating a battery. For example, Patent Document 1 describes a non-contact power supply device that supplies power to a power receiving device in a non-contact manner. When the detected temperature exceeds a predetermined temperature due to the presence of a foreign object on the charging stand, the non-contact power supply device described in Patent Document 1 stops power supply.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, it is considered that there is room for improvement in the power supply control described in Patent Document 1. For example, in the power supply control described in Patent Document 1, the predetermined temperature is not adjusted, but it is considered preferable to adjust the predetermined temperature. Therefore, a technique for realizing appropriate power supply based on the detected temperature is desired.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a power supply device, a power supply method, and a program that realize appropriate power supply based on the detected temperature.

Means for Solving the Problems

[0006] To achieve the above objective, the power supply device according to this disclosure comprises a power supply unit that supplies power to a power receiving device, a temperature detection unit that detects the temperature of a predetermined part of the power supply device, and a control unit that controls the power supply to the power receiving device by the power supply unit based on the detected temperature, which is the temperature detected by the temperature detection unit, and a reference temperature. The control unit updates the reference temperature to the detected temperature at the start of power supply if, at the start of power supply, a first specified time or more has elapsed since the end of the previous power supply, and the rate of change of the detected temperature during the specified period immediately before the start of power supply is within the reference value. [Effects of the Invention]

[0007] According to this disclosure, it is possible to achieve appropriate power supply based on the detected temperature. [Brief explanation of the drawing]

[0008] [Figure 1] Perspective view of the power supply device and power receiving equipment according to Embodiment 1 [Figure 2] Cross-sectional view of the power supply device according to Embodiment 1 [Figure 3] Enlarged view of the area enclosed by the dashed line 50 shown in Figure 2. [Figure 4] Configuration diagram of the power transmission system according to Embodiment 1 [Figure 5] This figure shows an example of the relationship between time and detected temperature when the reference temperature is not updated. [Figure 6] This figure shows an example of the relationship between time and detected temperature when the reference temperature is updated. [Figure 7] Flowchart showing the power supply management process performed by the power supply device according to Embodiment 1 [Figure 8] Figure 7 shows the power supply control process in a flowchart. [Figure 9] A flowchart showing the power supply management process performed by the power supply device according to Embodiment 2. [Figure 10] Configuration diagram of the power transmission system according to Embodiment 3 [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals. The power transmission system 1000 according to Embodiment 1 shown in Figure 1 is a system in which a power supply device 100 wirelessly supplies power to a power receiving device 200. The power supply device 100 wirelessly supplies power to the power receiving device 200 when the power receiving device 200 is housed in the storage compartment 110 provided by the power supply device 100. Wireless means that there are no cable connections, electrode contacts, etc.

[0010] The power supply device 100 functions as a charging station for charging the battery of the power receiving device 200. The power supply device 100 receives power from an AC (Alternating Current) adapter equipped with a DC (Direct Current) plug 191. The power supply device 100 includes a storage compartment 110 for housing the power receiving device 200. The storage compartment 110 is shaped like a small animal house, and has a bowl-like shape, or more specifically, like an egg divided in two by a plane containing a central axis extending in the longitudinal direction. A bottom plate 111 on which the power receiving device 200 is placed is provided at the bottom of the storage compartment 110. A coil cover 131 is embedded in the bottom plate 111 such that the top surface of the bottom plate 111 and the top surface of the coil cover 131 are in the same plane. The power receiving device 200 is placed on the bottom plate 111 with the coil cover 131 embedded in it. The coil cover 131 is a component that protects the power transmission coil 130, and is a disc-shaped component.

[0011] Multiple protrusions 112 are provided on the inside of the side wall of the storage section 110. The multiple protrusions 112 are members that restrict the horizontal movement of the power receiving equipment 200 when the power receiving equipment 200 is stored in the storage section 110 and power can be supplied to the power receiving equipment 200 (hereinafter referred to as the "storage state" as appropriate). A protrusion 113 is provided in the center of the bottom plate 111. The protrusion 113 is a member that restricts the longitudinal movement of the storage section 110 by the power receiving equipment 200 when the storage state is reached. The protrusion 113 has a shape that extends in the width direction of the storage section 110. Preferably, the multiple protrusions 112 and the protrusion 113 are arranged so as not to excessively restrict the movement of the power receiving equipment 200, that is, to allow some movement of the power receiving equipment 200. With this configuration, for example, the breathing motion simulated by the power receiving device 200, which is modeled after a small animal, within the storage unit 110, which is modeled after a small animal's home, is not restricted. A magnet 150 is provided inside the protrusion 113. When the power receiving device 200 is stored in the storage unit 110 and the magnetic field emitted by the magnet 150 is detected by the power receiving device 200, the power supply device 100 starts supplying power to the power receiving device 200.

[0012] In this embodiment, the axis extending vertically is defined as the Z-axis, the axis extending perpendicular to the Z-axis is defined as the X-axis, and the axis extending perpendicular to both the Z-axis and the X-axis is defined as the Y-axis. In this embodiment, the power supply device 100 is positioned such that the direction extending from the rear end to the front end in the longitudinal direction of the storage unit 110 is the positive direction of the X-axis. The front end in the longitudinal direction of the storage unit 110 is the more pointed end of the two ends in the longitudinal direction of the storage unit 110.

[0013] The power receiving device 200 is a device that operates using power stored in its built-in battery. The power receiving device 200 charges its built-in battery with power supplied from the power supply device 100. In this embodiment, the power receiving device 200 is a robot that operates autonomously without direct operation by a user. More specifically, the power receiving device 200 is a pet robot that mimics a small animal. The power receiving device 200 comprises a main body 210 and an outer casing 220. The main body 210 is the part that houses various components necessary for the operation of the power receiving device 200. As shown in Figure 2, the main body 210 comprises a head 211, a connecting part 212, and a torso 213. Figure 2 is a schematic diagram showing a cross-section of the power supply device 100 and the power receiving device 200 in their stored state, when cut by a plane extending in the longitudinal and vertical directions of the storage part 110.

[0014] In Figure 2, for ease of understanding, the exterior part 220 of the power receiving device 200 is omitted from the illustration, and only the main body part 210 is shown. Also in Figure 2, hatching on the cross-section is omitted for ease of understanding. The head 211 is the part corresponding to the head of a small animal. The connecting part 212 is the part that rotatably connects the head 211 and the body part 213. The body part 213 is the part corresponding to the body of a small animal. Inside the body part 213 are the power receiving coil 230 and the magnetic sensor 250. The exterior part 220 is the exterior part that covers the main body part 210. The exterior part 220 is equipped with decorative parts that resemble eyes and fluffy fur. The surface of the exterior part 220 is formed of an artificial pile fabric that mimics the fur of a small animal, for example, in order to simulate the feel of the skin of a small animal. The lining of the exterior part 220 is made of, for example, fiber, leather, rubber, etc. Since the exterior part 220 is made of a flexible material, it can follow the movement of the main body part 210.

[0015] Note that the power receiving device 200 may be automatically stored in the storage unit 110 or manually stored in the storage unit 110. For example, the power receiving device 200 may automatically move into the storage unit 110 in response to the remaining battery level reaching or falling below a reference value. Alternatively, the user may store the power receiving device 200 in the storage unit 110 according to the notification from the power receiving device 200. This notification is a notification that the remaining battery level is low, and is a notification issued by the power receiving device 200 in response to the remaining battery level reaching or falling below a reference value.

[0016] As shown in FIG. 2, when the power receiving device 200 is stored in the storage unit 110, the magnetic sensor 250 and the magnet 150 are close to each other, and the magnetic sensor 250 can detect the magnetism generated by the magnet 150. Also, when the power receiving device 200 is stored in the storage unit 110, the power transmission coil 130 and the power receiving coil 230 are close to each other and face each other, enabling power supply from the power supply device 100 to the power receiving device 200.

[0017] As shown in FIG. 3, the power supply device 100 includes a power transmission coil 130, a coil cover 131, a heat conduction member 132, a thermally conductive double-sided tape 133, a pedestal 134, a substrate 135, a temperature sensor 140, a pressing member 142, and a flexible printed wiring board 143. The coil cover 131 protects the power transmission coil 130. The upper surface of the coil cover 131 is a mounting surface 131A on which the power receiving device 200 is disposed. The coil cover 131 is formed of a material that does not generate heat during power supply using the power transmission coil 130. For example, the coil cover 131 is formed of plastic. The coil cover 131 is an example of a mounting portion. A heat conduction member 132 is attached to the lower surface of the coil cover 131 by a thermally conductive double-sided tape 133. The heat conduction member 132 is formed of a member having a high thermal conductivity. For example, the heat conduction member 132 is formed of an acrylic-based material, a silicon-based material, or the like. The thermally conductive double-sided tape 133 is a double-sided tape formed of a member having a high thermal conductivity. For example, the thermally conductive double-sided tape is formed by applying a highly thermally conductive acrylic-based adhesive to both sides of a polyether ether ketone resin film, a polyethylene terephthalate film, or the like.

[0018] The pedestal 134 is a member that supports the power transmission coil 130. The power transmission coil 130 is disposed on the upper surface of the pedestal 134. The pedestal 134 is formed of an insulating material typified by, for example, plastic. The substrate 135 is a printed circuit board on which various electronic components are mounted. A power transmission circuit, a control circuit, etc. are mounted on the substrate 135. The temperature sensor 140 is a sensor that detects the temperature of the heat conduction member 132. The temperature sensor 140 is a contact-type temperature sensor such as a resistance temperature detector, a linear resistor, or a thermistor. The temperature sensor 140 is provided at the lower center of the heat conduction member 132. The temperature sensor 140 is mounted on the flexible printed wiring board 143 and housed in a through hole (not shown) provided in the pressing member 142. The temperature information indicating the temperature detected by the temperature sensor 140 is transmitted via the flexible printed wiring board 143 to the electronic components mounted on the substrate 108.

[0019] The pressing member 142 is a member for pressing the printed wiring board 143 against the heat conduction member 132 by the force applied from the pedestal 134. The pressing member 142 is formed of an elastic member typified by rubber. The pressing member 142 is disposed at the lower center of the heat conduction member 132. The pressing member 142 has a through hole for housing the temperature sensor 140. By the pressing member 142, it is possible to press the printed wiring board 143 against the heat conduction member 132 without applying a load to the temperature sensor 140. The flexible printed wiring board 143 is a wiring board for transmitting temperature information from the temperature sensor 140 to the electronic components on the substrate 108. The flexible printed wiring board 143 is, for example, a wiring board in which a circuit pattern is formed on a resin film having a high thermal conductivity. When a foreign object existing on the coil cover 131 generates heat due to power supply, the heat generated by the foreign object is transmitted to the temperature sensor 140 via the coil cover 131, the thermally conductive double-sided tape 133, the heat conduction member 132, and the flexible printed wiring board 143. In the present embodiment, the foreign object is a metal foreign object that generates heat in response to a change in magnetic flux.

[0020] The temperature sensor 140 is located in the lower center of the heat conduction member 132. Therefore, regardless of where the foreign object is positioned on the coil cover 131, it is possible to efficiently detect the heat emitted by the foreign object. In addition, the heat conduction member 132 diffuses the heat emitted by the foreign object, thus mitigating the temperature rise of the foreign object. Furthermore, the thermal conductivity of the coil cover 131 is lower than that of the heat conduction member 132. Therefore, heat conduction on the coil cover 131 is suppressed, and the transfer of heat emitted by the foreign object to the power receiving device 200 is suppressed.

[0021] The power transmission system 1000 shown in Figure 4 comprises a power supply device 100 and a power receiving device 200. The power supply device 100 comprises a power transmission coil 130, a temperature sensor 140, a magnet 150, a power transmission circuit 160, a control circuit 170, and a power supply circuit 180. The power receiving device 200 comprises a power receiving coil 230, a sensor 241, an actuator 242, a speaker 243, a magnetic sensor 250, a power receiving circuit 260, a control circuit 270, and a battery 280. The power transmission coil 130 is a coil coupled to the power receiving coil 230 and is a coil for wireless power supply. The power transmission coil 130 induces a magnetic flux whose magnitude changes when an alternating current flows through it. The power transmission coil 130 is a conductor wound around an axis extending in the Z-axis direction. In its retracted state, the power transmission coil 130 is positioned in a predetermined location within the power supply device 100 such that it faces the power receiving coil 230. In the retracted state, the central axis of the power receiving coil 230 and the central axis of the power transmission coil 130 are in close proximity.

[0022] The temperature sensor 140 detects the temperature of a predetermined part of the power supply device 100. In this embodiment, the temperature sensor 140 detects the temperature of the heat conductive member 132. If foreign matter containing metal is present around the power transmission coil 130, eddy currents flow within this foreign matter due to the change in magnetic flux induced by the power transmission coil 130, causing this foreign matter to generate heat. The temperature sensor 140 is mainly used to detect this heat generation from the foreign matter. The temperature sensor 140 supplies temperature information indicating the temperature detection result to the control circuit 170. The temperature sensor 140 is an example of a temperature detection unit. The heat conductive member 132 is an example of a predetermined part.

[0023] The magnet 150 is an object that emits magnetism. The magnet 150 has two poles, a north pole and a south pole, and is an object that generates a bipolar magnetic field. The magnet 150 is placed in a specific location on the power supply device 100 to indicate that the power supply device 100 is a suitable power supply device for supplying power to the power receiving device 200. In this embodiment, the specific location is the projection 113. The magnet 150 is installed at a position and angle corresponding to the position and angle of the magnetic sensor 250. That is, in the stored state, the magnet 150 is positioned at a position and angle that allows the magnetic field emitted by the magnet 150 to be detected by the magnetic sensor 250. In this embodiment, the magnet 150 is a permanent magnet.

[0024] The power transmission circuit 160 is a circuit for supplying power to the power receiving equipment 200. The power transmission circuit 160 is a circuit for wirelessly supplying power via the power transmission coil 130. The power transmission circuit 160 supplies AC power based on DC power supplied from the power supply circuit 180 to the power transmission coil 130. The power transmission circuit 160 operates according to the control of the control circuit 170. The power transmission circuit 160 communicates with the power receiving circuit 260. Specifically, when the power transmission circuit 160 receives a power supply request from the power receiving circuit 260, it starts supplying power to the power receiving circuit 260. The power transmission circuit 160 includes a power transmission IC 161. The power transmission IC 161 converts the DC power generated by the power supply circuit 180 into AC power and supplies the AC power to the power transmission coil 130. The power transmission circuit 160 is an example of a power supply unit. The control circuit 170 controls the overall operation of the power supply device 100. For example, the control circuit 170 controls the power transmission circuit 160 to supply power to the power receiving device 200. The control circuit 170 controls the power supply to the power receiving device 200 based on the detection result from the temperature sensor 140. If the control circuit 170 detects an abnormality, it may notify the power receiving device 200 that an abnormality has been detected, causing the power receiving device 200 to notify that there is an abnormality. Examples of abnormalities include excessive temperature rise due to foreign matter or misalignment, and a decrease in transmission efficiency due to misalignment. The control circuit 170 is an example of a control unit.

[0025] The control circuit 170 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), RTC (Real Time Clock), flash memory, etc. The CPU is also called a central processing unit, central computing unit, processor, microprocessor, microcomputer, DSP (Digital Signal Processor), etc., and functions as a central computing unit that executes processing and calculations related to the control of the control circuit 170. In the control circuit 170, the CPU reads programs and data stored in the ROM, flash memory, etc., and uses the RAM as a work area to comprehensively control the control circuit 170. The RTC is, for example, an integrated circuit with a timing function. The CPU can determine the current date and time from the time information read from the RTC.

[0026] The power supply circuit 180 generates various power supply voltages used by the power supply device 100. For example, the power supply circuit 180 steps down or steps up the DC voltage supplied from the AC adapter 190 to generate the power supply voltages for each part of the power supply device 100. The AC adapter 190 is a device for converting AC power to DC power. In this embodiment, the AC adapter 190 converts AC power supplied from the commercial power source to DC power and supplies the DC power to the power supply circuit 180. The AC adapter 190 is equipped with a DC plug 191 connected to the power supply circuit 180. The receiving coil 230 is a coil coupled to the transmitting coil 130 and is a coil for receiving power wirelessly. The receiving coil 230 induces an electromotive force in response to the change in magnetic flux induced by the transmitting coil 130. The receiving coil 230 is a conductor wound around an axis extending in the Z-axis direction.

[0027] Sensor 241 is a sensor for detecting various physical quantities. Possible examples of sensor 241 include touch sensors, acceleration sensors, angular velocity sensors, sound sensors, illuminance sensors, and temperature sensors. A touch sensor, for example, detects when a user touches the outer casing 220. An acceleration sensor, for example, detects the acceleration applied to all or part of the power receiving device 200. An angular velocity sensor, for example, detects the angular velocity of all or part of the power receiving device 200. A sound sensor, for example, detects sounds made by a user. An illuminance sensor, for example, detects the illuminance around the power receiving device 200. A temperature sensor, for example, detects the temperature inside or outside the power receiving device 200. Sensor 241 supplies an electrical signal indicating the detection result to the control circuit 270. Actuator 242 is a mechanism for operating various parts of the power receiving device 200. Actuator 242 operates according to the control of the control circuit 270. For example, the actuator 242 is a mechanism for moving the power receiving device 200 in the forward and backward directions, or for rotating the head 211 relative to the body 213. The actuator 242 includes, for example, a stepping motor.

[0028] Speaker 243 emits sound according to control by control circuit 170. For example, if the power supply device 100 detects an abnormality, speaker 243 outputs an audio signal from control circuit 170 to indicate that an abnormality has been detected. Magnetic sensor 250 is a sensor that detects magnetism. Magnetic sensor 250 detects the magnetism emitted by a magnet 150 provided at a specific location on the power supply device 100. Magnetic sensor 250 outputs a first voltage when it detects magnetism and a second voltage when it does not detect magnetism. The voltage output by magnetic sensor 250 is applied to the operation control terminal 262 of the power receiving IC 261. As will be described later, power supply is permitted when magnetism is detected and not permitted when magnetism is not detected. Note that magnetic sensor 250 is installed at a position and angle that does not detect the magnetism generated by the power transmission coil 130.

[0029] The power receiving circuit 260 is a circuit for receiving power wirelessly via the power receiving coil 230. The power receiving circuit 260 supplies DC power based on AC power supplied from the power supply device 100 via the power receiving coil 230 to the battery 280. The power receiving circuit 260 operates according to the control of the control circuit 270. The power receiving circuit 260 communicates with the power transmitting circuit 160. For example, the power receiving circuit 260 sends a power supply request to the power transmitting circuit 160 in order to receive power from the power transmitting circuit 160. The power receiving circuit 260 includes a power receiving IC (Integrated Circuit) 261. The power receiving IC 261 converts the AC power generated by the electromotive force induced by the power receiving coil 230 into DC power and supplies the DC power to the battery 280. The power receiving IC 261 includes an operation control terminal 262 for controlling the operation of the power receiving IC 261. The power receiving IC 261 operates when a first voltage is applied to the operation control terminal 262, and stops operating when a second voltage is applied to the operation control terminal 262.

[0030] When a first voltage is applied to the operation control terminal 262, the power receiving IC 261 operates. Therefore, the power receiving circuit 260 sends a power supply request to the power transmission circuit 160, and power is supplied by the power supply device 100. On the other hand, when a second voltage is applied to the operation control terminal 262, the power receiving IC 261 stops operating. Therefore, the power receiving circuit 260 does not send a power supply request to the power transmission circuit 160, and power is not supplied by the power supply device 100. The control circuit 270 controls the overall operation of the power receiving device 200. For example, the control circuit 270 operates the power receiving device 200 by operating the actuator 242 based on the detection result from the sensor 241. Also, if the control circuit 270 receives notification from the power supply device 100 that an abnormality has been detected, it controls the speaker 243 to notify the user that an abnormality has been detected. The control circuit 270 includes a CPU, ROM, RAM, RTC, flash memory, etc.

[0031] Battery 280 is a rechargeable secondary battery. Battery 280 is the power source for the powered device 200. In other words, battery 280 supplies power to the sensor 241, actuator 242, magnetic sensor 250, power receiving circuit 260, control circuit 270, etc. Battery 280 is also charged by the power supplied from the power receiving circuit 260. The control circuit 170 controls the power supply to the powered device 200 by the power transmission circuit 160 based on the detected temperature, which is the temperature detected by the temperature sensor 140, and the reference temperature.

[0032] The control circuit 170 interrupts power supply if the detected temperature rises to the interruption temperature during power supply. The control circuit 170 resumes power supply if the detected temperature drops to the restart temperature during power supply interruption. The interruption temperature is the temperature at which power supply is interrupted. The restart temperature is the temperature at which power supply is resumed. The interruption temperature and restart temperature are temperatures set based on a reference temperature. The reference temperature is basically the detected temperature at the start of power supply. The interruption temperature is a temperature higher than the reference temperature by a first predetermined temperature. The restart temperature is a temperature lower than the interruption temperature by a second predetermined temperature. In this embodiment, the first predetermined temperature is 20°C and the second predetermined temperature is 5°C.

[0033] The control circuit 170 updates the reference temperature to the detected temperature at the start of power supply if, at the start of power supply, at least one specified time has elapsed since the end of the previous power supply, and the rate of change of the detected temperature during the specified period immediately preceding the start of power supply is within the reference value. The control circuit 170 does not update the reference temperature if, at the start of power supply, at least one specified time has elapsed since the end of the previous power supply, and the rate of change is not within the reference value. Also, the control circuit 170 does not update the reference temperature if, at the start of power supply, at least one specified time has elapsed since the end of the previous power supply. The first specified time is a time shorter than the time it is thought to take for the detected temperature, which has risen due to power supply, to decrease. For example, the first specified time is 2 minutes. The specified period is the period for which the rate of change of the detected temperature is to be determined. For example, the specified period is the 2 minutes immediately preceding the start of power supply.

[0034] The rate of change corresponds to the magnitude of the change in detected temperature over a specified period. How the rate of change is defined can be adjusted as appropriate. For example, the rate of change may be the slope of the straight line when the detected temperature is approximated by a straight line in a graph showing detected temperature and time over a specified period. In other words, the rate of change may be the regression coefficient, which is the slope of the regression line when a regression analysis is performed with detected temperature as the dependent variable and the detection time of the detected temperature as the independent variable. Alternatively, the rate of change may be the value obtained by dividing the temperature difference between the detected temperature at the beginning and end of the specified period by the length of the specified period. Alternatively, the rate of change may be the value obtained by dividing the temperature difference between the highest and lowest detected temperatures over the specified period by the length of the specified period. The reference value is a threshold for determining the rate of change. For example, assuming that the detected temperature continues to decrease over a specified period, the rate of change is defined as the ratio of the decrease in detected temperature over the specified period to the length of the specified period. Also, the length of the specified period is set to 2 minutes, and the reference value is set to 2.5°C / min. In this case, the reference temperature is updated if the detected temperature does not drop by 5°C or more within the specified period, and the reference temperature is not updated if the detected temperature drops by 5°C or more within the specified period.

[0035] Thus, the control circuit 170 updates the reference temperature to the current detected temperature only if a certain amount of time has passed since the last power supply and the most recent detected temperature is stable. However, the control circuit 170 does not update the reference temperature if not much time has passed since the last power supply. The control circuit 170 terminates power supply if the detected temperature rises to a predetermined upper limit temperature during power supply. In other words, regardless of the comparison result between the detected temperature and the interruption temperature, the control circuit 170 terminates power supply if the detected temperature reaches the upper limit temperature. In this embodiment, the upper limit temperature is 60°C.

[0036] As shown in Figure 5, we assume a case where the reference temperature is not updated, and at t10, the power receiving equipment 200 is set on the power supply device 100 and power supply begins. Here, the detected temperature is constant during the period from t11 to t10, which is a specified period immediately before the start of power supply. In this case, the range of change in the detected temperature during the specified period is 0°C, and the rate of change in the detected temperature during the specified period is less than or equal to the reference value. Also, the elapsed time since the end of the previous power supply is greater than or equal to the first reference time. In this case, the reference temperature is updated to the current detected temperature. In Figure 5, d1 is the upper limit temperature, d10 is the detected temperature at t10, d11 is the detected temperature at t11, D11 is the range of change, D1 is the reference range, T11 is the elapsed time from the end of the previous power supply to t10, T1 is the length of the first specified time, and T2 is the length of the specified period. The reference range is the threshold of the range of change in the detected temperature and is the temperature difference corresponding to the reference value of the rate of change. In other words, a change in the detected temperature that is greater than or equal to a reference range corresponds to a rate of change in the detected temperature that is greater than or equal to a reference value. For example, if the length of the specified period is 2 minutes and the reference value is 2.5°C / minute, the reference range D1 is 5°C. At time t10, the reference temperature is set to d10, which is the current detected temperature. The interruption temperature is set to d12, which is D2 higher than the reference temperature. The restart temperature is set to d13, which is D3 lower than the interruption temperature. Information indicating the reference temperature, interruption temperature, restart temperature, etc., is stored, for example, in the flash memory of the control circuit 170.

[0037] Thus, in this embodiment, the interruption temperature, restart temperature, etc., are variable values ​​set based on the detected temperature, and are not fixed values. The reason for this is that it is considered better to determine the interruption and restart of power supply based on the rise in the detected temperature due to power supply, rather than the detected temperature itself. With this configuration, for example, immediate interruption of power supply when the room temperature is high is suppressed, and excessive temperature rise due to power supply when the room temperature is low is suppressed. In contrast, if the interruption temperature, restart temperature, etc., are fixed values, for example, power supply may be immediately interrupted when the room temperature is high, and excessive temperature rise due to power supply may occur when the room temperature is low. When power supply is started at t10, the detected temperature rises. Basically, the detected temperature rises during power supply. However, if foreign matter is present, the detected temperature rises rapidly. Also, if there is a large misalignment between the transmitting coil 130 and the receiving coil 230, the detected temperature rises rapidly. Here, at t12, when the detected temperature rises to the interruption temperature d12, power supply is interrupted.

[0038] When power supply is interrupted at t12, the detected temperature decreases. At t13, when the detected temperature decreases to the restart temperature d13, power supply is resumed. When power supply is resumed at t13, the detected temperature increases. Thereafter, similarly, when the detected temperature rises to the interruption temperature, power supply is interrupted, and when the detected temperature decreases to the restart temperature, power supply is resumed. At t14, when the power receiving device 200 is removed from the power supply device 100, power supply ends. When power supply ends at t14, the detected temperature decreases. At t20, when the power receiving device 200 is placed back into the power supply device 100, power supply begins.

[0039] In this embodiment, the termination of power supply and the interruption of power supply are clearly distinguished, as are the start of power supply and the restart of power supply. Specifically, the termination of power supply is defined as the cessation of power supply due to the removal of power receiving equipment 200, full charging, or reaching the upper limit of the detected temperature, and the cessation of power supply due to reaching the interruption temperature of the detected temperature is defined as the interruption of power supply. Furthermore, the start of power supply by setting up power receiving equipment 200 is defined as the start of power supply, and the start of power supply due to reaching the restart temperature of the detected temperature is defined as the restart of power supply. T21 is the length of time from t14 to t20, d21 is the detected temperature at t21, d20 is the detected temperature at t20, and D21 is the temperature difference between d21 and d20. When T21 is greater than or equal to T1, and D21 is greater than D1, the reference temperature is not updated. In other words, the reference temperature is not updated to d20, which is the detected temperature at t20, but is maintained at d10, which is the detected temperature at t10. Therefore, the interruption temperature is maintained at d12, and the restart temperature is maintained at d13. Subsequently, when power supply is started at t20, the detected temperature rises, and when the detected temperature rises to the interruption temperature d12 at t22, power supply is interrupted. Also, when power supply is interrupted at t22, the detected temperature decreases, and when the detected temperature drops to the restart temperature d13 at t23, power supply is restarted.

[0040] Next, with reference to Figure 6, an example of how the reference temperature is updated will be explained. From t11 to t14, the process is as described with reference to Figure 5. At t30, when the power receiving equipment 200 is repositioned on the power supply device 100, power supply is started. T31 is the length of time from t14 to t30, d31 is the detected temperature at t31, d30 is the detected temperature at t30, and D31 is the temperature difference between d31 and d30. If T31 is greater than or equal to T1 and D31 is less than or equal to D1, the reference temperature is updated from d10, the detected temperature at t10, to d30, the detected temperature at t30. The interruption temperature is also updated to d32, which is D2 higher than d30. The restart temperature is updated to d33, which is D3 lower than d32. Thereafter, when power supply is started at t30, the detected temperature rises, and when the detected temperature rises to the interruption temperature d32 at t32, power supply is interrupted. Furthermore, if power supply is interrupted at t32, the detected temperature decreases, and power supply is resumed at t33 when the detected temperature drops to the restart temperature d33.

[0041] Thus, if the first reference time has elapsed since the end of the previous power supply at the start of power supply, and the rate of change of the detected temperature during the specified period immediately preceding the start of power supply is below the reference value, the reference temperature is updated. On the other hand, if the first specified time has elapsed since the end of the previous power supply at the start of power supply, and the rate of change of the detected temperature during the specified period immediately preceding the start of power supply is greater than the reference value, the reference temperature is not updated. The reason for this is to prevent the reference temperature from being set to an excessively high temperature. In other words, as described above, if the power receiving device 200 is immediately repositioned after the end of power supply due to the removal of the power receiving device 200, the detected temperature at the start of power supply will be higher than the ambient temperature. For this reason, if the detected temperature at the start of power supply is set as the reference temperature, the interruption temperature will be set to an excessively high temperature. In particular, if the power receiving device 200 is repeatedly repositioned during power supply, the reference temperature, interruption temperature, etc. will be set to an excessively high temperature.

[0042] However, setting the interruption temperature to an excessively high temperature is undesirable as it allows power supply at high temperatures. Therefore, if the first reference time has elapsed since the end of the previous power supply at the start of power supply, and the above rate of change is greater than the reference value, the reference temperature is not updated, and the previously set reference temperature is maintained. Note that if power supply is started immediately after the end of power supply, the detected temperature is decreasing, and the above rate of change is considered to be large. In other words, if the above rate of change is small at the start of power supply, it is considered that the detected temperature has decreased to around room temperature, rather than immediately after the end of power supply. Therefore, in this embodiment, by detecting a small rate of change, it is detected that the detected temperature has decreased sufficiently. Note that if it is clear that power supply has just ended, that is, if the first reference time has not elapsed since the end of the previous power supply, the reference temperature is not updated.

[0043] Next, as shown in Figure 7, the power supply management process performed by the power supply device 100 will be described. First, the control circuit 170 of the power supply device 100 detects the temperature (step S101). For example, the control circuit 170 acquires temperature information indicating the temperature detected by the temperature sensor 140. After completing the process in step S101, the control circuit 170 determines whether or not the installation of the power receiving device 200 has been detected (step S102). For example, the control circuit 170 sends a signal to the power receiving device 200 using the power transmission circuit 160, and if the power receiving device 200 responds to this signal, it determines that the installation of the power receiving device 200 has been detected. After completing the process in step S102, the control circuit 170 determines whether or not a first specified time has elapsed since the end of the previous power supply (step S103). The control circuit 170 can identify the time when the previous power supply ended by referring to the power supply end time information stored in the flash memory of the control circuit 170. Power supply termination time information is information indicating the time when power supply ends, and is, for example, information stored in flash memory each time power supply ends.

[0044] If the control circuit 170 determines that more than one specified time has elapsed since the last power supply ended (step S103: YES), it determines whether the rate of change of the detected temperature is within a reference value (step S104). For example, the control circuit 170 determines whether the difference between the maximum value of the detected temperature in the most recent specified period and the minimum value of the detected temperature in the most recent specified period is less than or equal to a reference range. If the control circuit 170 determines that the rate of change of the detected temperature is within a reference value (step S104: YES), it sets the detected temperature to the reference temperature (step S105). In other words, the control circuit 170 updates the reference temperature to the current detected temperature. After completing the process in step S105, the control circuit 170 sets the interruption temperature and the restart temperature based on the reference temperature (step S106).

[0045] The control circuit 170 executes the power supply control process (step S107) if it determines that no more than the first specified time has elapsed since the end of the previous power supply (step S103: NO), if it determines that the rate of change of the detected temperature is not within the reference value (step S104: NO), or if it has completed the process in step S106. The power supply control process will be described below with reference to the flowchart shown in Figure 8. First, the control circuit 170 starts supplying power (step S201). For example, the control circuit 170 starts supplying power to the power receiving equipment 200 via the power transmission circuit 160. After completing the process in step S201, the control circuit 170 detects the temperature (step S202). After completing the process in step S202, the control circuit 170 determines whether or not power is being supplied (step S203). If the control circuit 170 determines that power is being supplied (step S203: YES), it determines whether or not the detected temperature has reached the interruption temperature (step S204). When the control circuit 170 determines that the detected temperature has reached the interruption temperature (step S204: YES), it interrupts the power supply (step S205). In other words, the control circuit 170 controls the power transmission circuit 160 to temporarily stop the power supply to the power receiving device 200.

[0046] If the control circuit 170 determines that power is not being supplied (step S203: NO), it determines whether the detected temperature has reached the restart temperature (step S206). If the control circuit 170 determines that the detected temperature has reached the restart temperature (step S206: YES), it restarts power supply (step S207). In other words, the control circuit 170 controls the power transmission circuit 160 to restart power supply to the powered device 200. If the control circuit 170 determines that the detected temperature has not reached the interruption temperature (step S204: NO), if it determines that the detected temperature has not reached the restart temperature (step S206: NO), or if it has completed the processing in step S205 or step S207, it determines whether the powered device 200 is fully charged (step S208). For example, if the control circuit 170 receives a signal from the powered device 200 indicating that it is fully charged, it determines that the powered device 200 is fully charged.

[0047] If the control circuit 170 determines that the powered device 200 is not fully charged (step S208: NO), it determines whether or not the removal of the powered device 200 has been detected (step S209). If the control circuit 170 determines that the removal of the powered device 200 has not been detected (step S209: NO), it determines whether or not the detected temperature has reached the upper limit temperature (step S210). If the control circuit 170 determines that the detected temperature has not reached the upper limit temperature (step S210: NO), it returns to step S202. If the control circuit 170 determines that the powered device 200 is fully charged (step S208: YES), if it determines that the removal of the powered device 200 has been detected (step S209: YES), or if it determines that the detected temperature has reached the upper limit temperature (step S210: YES), it terminates the power supply (step S211). Once the control circuit 170 completes the process in step S211, it completes the power supply control process. When the control circuit 170 completes the power supply control process in step S107, it returns to step S101.

[0048] In this embodiment, if a first specified time has elapsed since the end of the previous power supply at the start of power supply, and the rate of change of the detected temperature during the specified period immediately preceding the start of power supply is within a reference value, the reference temperature is updated to the detected temperature at the start of power supply. Therefore, in this embodiment, the reference temperature used for controlling power supply is prevented from being set to an excessively high temperature. Thus, according to this embodiment, appropriate power supply based on the detected temperature can be achieved. Furthermore, in this embodiment, if the detected temperature rises to the interruption temperature based on the reference temperature during power supply, power supply is interrupted, and if the detected temperature falls to the restart temperature based on the reference temperature during the power supply interruption, power supply is restarted. According to this embodiment, appropriate power supply can be achieved within a range where the detected temperature does not exceed the interruption temperature.

[0049] Furthermore, in this embodiment, if the detected temperature rises to a predetermined upper limit temperature during power supply, power supply is terminated. According to this embodiment, excessive temperature rise due to power supply is reliably suppressed. In addition, in this embodiment, when the power receiving device 200 is placed on the mounting surface 131A, the temperature of the heat conductive member 132 placed between the power receiving device 200 and the power transmission coil 130 is detected as the detected temperature. According to this embodiment, appropriate power supply based on the detected temperature can be achieved in contactless power supply.

[0050] Next, Embodiment 2 will be described. In Embodiment 1, the temperature difference between the detected temperature at the start of power supply and the reference temperature is not considered, whereas in this embodiment, the temperature difference between the detected temperature at the start of power supply and the reference temperature is considered. Note that the same configuration and functions as in Embodiment 1 will be omitted or simplified as appropriate. In this embodiment, if the control circuit 170 has elapsed for more than one specified time since the end of the previous power supply at the start of power supply, and the rate of change is within the reference value, and the temperature difference between the detected temperature at the start of power supply and the reference temperature is less than or equal to the temperature difference threshold, the control circuit 170 will update the reference temperature to the detected temperature at the start of power supply. In other words, if the control circuit 170 has elapsed for more than one specified time since the end of the previous power supply at the start of power supply, even if the rate of change is within the reference value, the control circuit 170 will not update the reference temperature to the detected temperature at the start of power supply if the temperature difference between the detected temperature at the start of power supply and the reference temperature exceeds the temperature difference threshold.

[0051] For example, in Figure 6, d10 is the detected temperature at t10, d31 is the detected temperature at t31, d30 is the detected temperature at t30, D31 is the temperature difference between d31 and d30, D32 is the temperature difference between d10 and d30, T31 is the length of time from t14 to t30, T1 is the length of the first specified time, D1 is the reference width, and D4 is the temperature difference threshold. Also, at time t30, the reference temperature is d10. If T31 is greater than or equal to T1, D31 is less than or equal to D1, and D32 is less than or equal to D4, the reference temperature is updated from d10 to d30. On the other hand, if T31 is greater than or equal to T1, D31 is less than or equal to D1, and D32 is greater than D4, the reference temperature is not updated.

[0052] The reason for considering the temperature difference between the detected temperature at the start of power supply and the reference temperature is to further prevent the setting of an excessively high reference temperature. For example, if power supply is started immediately after the previous power supply has ended, the detected temperature may not decrease significantly for some reason immediately before power supply starts. In this case, if the temperature difference between the detected temperature at the start of power supply and the reference temperature is not considered, an excessively high detected temperature will be set as the reference temperature. On the other hand, if the temperature difference between the detected temperature at the start of power supply and the reference temperature is considered, the setting of an excessively high detected temperature as the reference temperature is suppressed. For example, even if power supply is started when the detected temperature remains high for some reason, the reference temperature will not be updated to the high detected temperature. Note that if the temperature difference between the detected temperature at the start of power supply and the reference temperature is below the temperature difference threshold, it basically means that the current detected temperature has decreased to close to the detected temperature at the start of the previous power supply.

[0053] The power supply management process performed by the power supply device 100 will be described below with reference to the flowchart shown in Figure 9. The processes from step S101 to step S103 are as described in Embodiment 1. When the control circuit 170 determines that more than one specified time has elapsed since the end of the previous power supply (step S103: YES), it determines whether the change in the detected temperature is within the reference value (step S104). When the control circuit 170 determines that the range of change in the detected temperature is within the reference range (step S104: YES), it determines whether the temperature difference between the detected temperature and the reference temperature is less than or equal to the temperature difference threshold (step S104A). When it determines that the temperature difference between the detected temperature and the reference temperature is less than or equal to the temperature difference threshold (step S104A: YES), it sets the detected temperature to the reference temperature (step S105). When the control circuit 170 completes the process in step S105, it sets the interruption temperature and the restart temperature based on the reference temperature (step S106). The control circuit 170 executes power supply control processing (step S107) if it determines that the first specified time has not elapsed since the end of the previous power supply (step S103: NO), if it determines that the rate of change of the detected temperature is not within the reference value (step S104: NO), if it determines that the temperature difference between the detected temperature and the reference temperature is not below the temperature difference threshold (step S104A: NO), or if it has completed the processing in step S106.

[0054] In this embodiment, if a first specified time has elapsed since the end of the previous power supply at the start of power supply, and the rate of change is within a reference value, and the temperature difference between the detected temperature at the start of power supply and the reference temperature is below a temperature difference threshold, the reference temperature is updated to the detected temperature at the start of power supply. Therefore, in this embodiment, the setting of the reference temperature used for power supply control to an excessively high temperature is further suppressed. Thus, according to this embodiment, appropriate power supply based on the detected temperature can be achieved.

[0055] Next, Embodiment 3 will be described. In Embodiment 1, power supply control is applied to contactless power supply, whereas in Embodiment 3, power supply control is applied to contact power supply. Note that the same configurations and functions as in Embodiments 1 and 2 will be omitted or simplified as appropriate. As shown in Figure 10, the power transmission system 1000A according to this embodiment comprises a power supply device 100A, a power receiving device 200A, and a power supply cable 300. The power supply device 100A comprises a connector 136, a temperature sensor 140, a power transmission circuit 160A, a control circuit 170, and a power supply circuit 180. The power receiving device 200A comprises a connector 236, a sensor 241, an actuator 242, a speaker 243, a power receiving circuit 260A, a control circuit 270, and a battery 280.

[0056] Connector 136 is a connector to which one end of the power supply cable 300 is connected. Connector 136 is connected to the power transmission circuit 160A. The power transmission circuit 160A is a circuit for supplying power to the powered equipment 200A via the power supply cable 300. The power transmission circuit 160A supplies DC power to the powered equipment 200A via the power supply cable 300, for example, based on DC power supplied from the power supply circuit 180. The power transmission circuit 160A includes a power transmission IC 161A. The power transmission IC 161A converts the DC power generated by the power supply circuit 180 into desired DC power. Connector 236 is a connector to which the other end of the power supply cable 300 is connected. Connector 236 is connected to the power receiving circuit 260A. The power receiving circuit 260A is a circuit for receiving power from the power supply device 100A via the power supply cable 300. The power receiving circuit 260A supplies DC power to the battery 280 based on DC power supplied from the power supply device 100A via the power supply cable 300, for example. The power receiving circuit 260A includes a power receiving IC 261A. The power receiving IC 261A converts the DC power supplied from the power supply device 100A into a desired DC power.

[0057] The temperature sensor 140 detects the temperature of a predetermined part of the power supply device 100A. For example, the temperature sensor 140 detects the ambient temperature around the power transmission circuit 160A. The temperature sensor 140 supplies temperature information indicating the detected temperature to the control circuit 170. The control circuit 170 performs power supply control based on the detected temperature indicated by the temperature information. The power supply control in this embodiment is basically the same as the power supply control in Embodiment 1. The power transmission circuit 160A is an example of a predetermined part. The control circuit 170 interrupts power supply if the detected temperature rises to the interruption temperature based on the reference temperature during power supply. The control circuit 170 resumes power supply if the detected temperature drops to the restart temperature based on the reference temperature after power supply interruption. If the control circuit 170 has elapsed for more than one specified time since the end of the previous power supply at the start of power supply, and the rate of change of the detected temperature during the specified period immediately before the start of power supply is within the reference value, it updates the reference temperature to the detected temperature at the start of power supply.

[0058] According to this embodiment, the same effects as in Embodiment 1 can be obtained. In other words, in this embodiment as well, the reference temperature used for controlling power supply is prevented from being set to an excessively high temperature. Therefore, appropriate power supply based on the detected temperature can also be achieved with this embodiment.

[0059] Although embodiments have been described above, various modifications and applications are possible. It is arbitrary which parts of the configuration, function, and operation described in the above embodiments are adopted. Furthermore, additional configurations, functions, and operations may be adopted in addition to those described above. Also, the configurations, functions, and operations described in the above embodiments can be freely combined. Embodiment 1 described an example in which an interruption temperature and a restart temperature are set based on a reference temperature, and power supply is controlled based on the interruption temperature and restart temperature. Alternatively, an end temperature may be set based on the reference temperature, and power supply may be controlled based on the end temperature. For example, when the detected temperature rises to the end temperature, power supply may be terminated instead of interrupted.

[0060] Embodiment 1 described an example in which power supply to the power receiving device 200 is stopped when it is detected that the power receiving device 200 is fully charged. When it is detected that the power receiving device 200 is fully charged, power supply to the power receiving device 200 may be continued at a reduced level compared to normal power supply. In this case as well, it is preferable that power supply is interrupted in response to the detected temperature reaching the interruption temperature, and power supply is resumed in response to the detected temperature reaching the restart temperature.

[0061] In Embodiment 1, an example was described in which the reference temperature is not updated if the rate of change of the detected temperature during the specified period immediately before the start of power supply exceeds a reference value, even if a sufficient amount of time has passed since the previous power supply. However, if a sufficient amount of time has passed since the previous power supply, the detected temperature is considered to have decreased sufficiently and settled to around room temperature. In this case, even if the reference temperature is updated to the detected temperature, it is considered unlikely that the reference temperature will be set to an excessively high temperature. Therefore, if a second specified time or longer than the first specified time has passed since the end of the previous power supply at the time of the start of power supply, the control circuit 170 may update the reference temperature to the detected temperature at the start of power supply, regardless of the rate of change of the detected temperature during the specified period immediately before the start of power supply. In other words, the control circuit 170 updates the reference temperature to the detected temperature at the start of power supply if a sufficient amount of time has passed since the previous power supply and the detected temperature is considered to have settled to around room temperature. The second specified time is the time considered to be required for the detected temperature, which has risen due to power supply, to decrease sufficiently. With this configuration, appropriate power supply based on the detected temperature and an appropriate reference temperature can be realized.

[0062] Embodiment 1 describes an example in which the power receiving device 200 is a robot modeled after a small animal. The power receiving device 200 may be any other robot or any device other than a robot. For example, the power receiving device 200 may be a smartphone, an electronic dictionary, a game device, etc. This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of this disclosure. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of this disclosure. In other words, the scope of this disclosure is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of the disclosure are considered to be within the scope of this disclosure. [Explanation of symbols]

[0063] 100, 100A power supply equipment, 160, 160A power transmission circuit, 140 temperature sensor, 170 control circuit, 200, 200A power receiving equipment

Claims

1. A power supply unit that supplies power to the receiving equipment, A temperature detection unit that detects the temperature of a predetermined part of the power supply device, The system includes a control unit that controls the power supply to the power receiving device by the power supply unit based on the detected temperature, which is the temperature detected by the temperature detection unit, and a reference temperature. If, at the start of power supply, a first specified time has elapsed since the end of the previous power supply, and the rate of change of the detected temperature during the specified period immediately preceding the start of power supply is within a reference value, the control unit updates the reference temperature to the detected temperature at the start of power supply. Power supply device.

2. The control unit interrupts power supply if the detected temperature rises to the interruption temperature based on the reference temperature during power supply interruption, and resumes power supply if the detected temperature drops to the restart temperature based on the reference temperature during power supply interruption. The power supply device according to claim 1.

3. The control unit updates the reference temperature to the detected temperature at the time of power supply commencement if, at the time of power supply commencement, the first specified time has elapsed or more since the end of the previous power supply, the rate of change is within the reference value, and the temperature difference between the detected temperature at the time of power supply commencement and the reference temperature is less than or equal to the temperature difference threshold. The power supply device according to claim 1 or 2.

4. If, at the start of power supply, a second specified time or longer than the first specified time has elapsed since the end of the previous power supply, the control unit updates the reference temperature to the detected temperature at the start of power supply. The power supply device according to claim 1 or 2.

5. The temperature of a predetermined part of the power supply device is detected, Based on the detected temperature and the reference temperature, the power supply to the power receiving device is controlled. If, at the start of power supply, more than one specified time has elapsed since the end of the previous power supply, and the rate of change of the detected temperature during the specified period immediately preceding the start of power supply is within the standard value, the standard temperature is updated to the detected temperature at the start of power supply. Power supply method.

6. The power supply device comprises a power supply unit that supplies power to a power receiving device and a temperature detection unit that detects the temperature of a predetermined part of the power supply device, and the computer included in the power supply device is A program that causes a control unit to function as a control unit that controls the power supply to the power receiving device by the power supply unit based on the detected temperature, which is the temperature detected by the temperature detection unit, and a reference temperature, If, at the start of power supply, a first specified time has elapsed since the end of the previous power supply, and the rate of change of the detected temperature during the specified period immediately preceding the start of power supply is within a reference value, the control unit updates the reference temperature to the detected temperature at the start of power supply. program.

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