Power supply device, power supply method, and computer program product

Abstract

The invention provides a power supply device, a power supply method and a computer program product. A power supply device is provided with: a power supply unit that supplies power to a power receiving device; a temperature detection unit that detects the temperature of the predetermined site; and a control unit that controls the supply of power to the power receiving device by the power supply unit on the basis of a detected temperature, which is the temperature detected by the temperature detection unit, and a reference temperature, the control unit being configured to control the supply of power to the power receiving device by the power supply unit when a first predetermined time has elapsed from the end of the previous power supply at the start of power supply. When the rate of change of the detected temperature within a predetermined period of time immediately before 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.

Description

TECHNICAL FIELD

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

[0002] A power supply device that supplies power to a power receiving apparatus having a built-in storage battery is known. For example, a non-contact power supply device that supplies power to a power receiving apparatus in a non-contact manner is described in Japanese Patent Application Publication No. 2015-195633. The non-contact power supply device described in Patent Document 1 stops power supply in a case where a temperature exceeds a predetermined temperature due to a foreign object existing in a charging stand. SUMMARY

[0003] PROBLEMS TO BE SOLVED BY THE INVENTION

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

[0005] The present disclosure was completed in view of the above-described problems, and aims to achieve appropriate power supply based on a detected temperature.

[0006] MEANS FOR SOLVING THE PROBLEMS

[0007] A power supply device according to an embodiment of the present disclosure includes a power supply portion that supplies power to a power receiving apparatus; a temperature detection portion that detects a temperature of a predetermined portion; and a control portion that controls power supply by the power supply portion to the power receiving apparatus based on a detected temperature detected by the temperature detection portion and a reference temperature, the control portion updating the reference temperature to the detected temperature at a time of start of power supply in a case where a change rate of the detected temperature in a predetermined period before the power supply is about to start is within a reference value in a case where a first predetermined time or more has elapsed from a time of end of last power supply.

[0008] EFFECTS OF THE INVENTION

[0009] According to the present disclosure, appropriate power supply based on a detected temperature can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a perspective view of a power supply device and a power receiving apparatus according to Embodiment 1.

[0011] Figure 2 is a cross-sectional view of the power supply device according to Embodiment 1.

[0012] Figure 3 is an enlarged view of a region enclosed by a broken line 50 shown in Figure 2 .

[0013] Figure 4 This is a structural diagram of the power transmission system involved in Implementation Method 1.

[0014] Figure 5 This is a graph illustrating the relationship between time and detection temperature when the reference temperature has not been updated.

[0015] Figure 6 This is a graph illustrating an example of the relationship between time and detection temperature when the reference temperature has been updated.

[0016] Figure 7 This is a flowchart illustrating the power supply management process performed by the power supply device involved in Implementation 1.

[0017] Figure 8 It means Figure 7 The flowchart shown is for the power supply control process.

[0018] Figure 9 This is a flowchart illustrating the power supply management process performed by the power supply device involved in Implementation Method 2.

[0019] Figure 10 This is a structural diagram of the power transmission system involved in Implementation Method 3. Detailed Implementation

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals. Figure 1 The power transmission system 1000 according to Embodiment 1 shown is a system in which a power supply device 100 wirelessly supplies power to a power receiving device 200. When the power receiving device 200 is housed in the housing 110 provided by the power supply device 100, the power supply device 100 wirelessly supplies power to the power receiving device 200. Wireless means without cable connection, electrode contact, etc.

[0021] The power supply unit 100 functions as a charging station for charging the battery of the power receiving device 200. The power supply unit 100 receives power from an AC (Alternating Current) adapter equipped with a DC (Direct Current) plug 191. The power supply unit 100 includes a storage section 110 for housing the power receiving device 200. The storage section 110 is shaped like a bowl, mimicking the shape of a small animal's home; more specifically, it has a shape like that of an egg divided into two parts by a plane containing a central axis extending in the long side direction. Furthermore, a base plate 111 for carrying the power receiving device 200 is provided at the bottom of the storage section 110. A coil cover 131 is embedded in the base plate 111 such that the upper surface of the base plate 111 and the upper surface of the coil cover 131 are flush with each other. The power receiving device 200 is carried on the base plate 111 with the coil cover 131 embedded in it. The coil cover 131 is a component that protects the power supply coil 130 and is a component with a circular plate shape.

[0022] A plurality of protrusions 112 are provided on the inner side of the sidewall of the storage section 110. The plurality of protrusions 112 are members that restrict the horizontal movement of the power receiving device 200 when it is stored in the storage section 110 and can be powered (hereinafter, appropriately referred to as the "stored state"). A protrusion 113 is provided at the center of the base plate 111. The protrusion 113 is a member that restricts the movement of the storage section 110 in the longitudinal direction caused by the power receiving device 200 in the stored state. The protrusion 113 has a shape extending along the width direction of the storage section 110. Preferably, the plurality of protrusions 112 and protrusions 113 are configured not to excessively restrict the movement of the power receiving device 200, that is, to allow some movement of the power receiving device 200. With such a structure, the simulated breathing movements of the power receiving device 200, for example, within the storage section 110 that simulates the home of a small animal, are not restricted. A magnet 150 is provided inside the protrusion 113. When the power receiving device 200 is housed in the storage unit 110 and the power receiving device 200 detects the magnetic force generated by the magnet 150, the power supply device 100 starts to supply power to the power receiving device 200.

[0023] In this embodiment, the axis extending vertically is designated as the Z-axis, the axis extending in a direction orthogonal to the Z-axis is designated as the X-axis, and the axis extending in a direction orthogonal to both the Z-axis and X-axis is designated as the Y-axis. Furthermore, in this embodiment, the power supply device 100 is configured such that the direction extending from the rear end to the front end of the long side of the storage portion 110 is the positive direction of the X-axis. The front end of the long side of the storage portion 110 is the more pointed end of the two ends of the long side of the storage portion 110.

[0024] The power receiving device 200 is a device that operates using electricity stored in its built-in battery. The power receiving device 200 charges its built-in battery using electricity supplied from the power supply unit 100. In this embodiment, the power receiving device 200 is a robot that operates autonomously without direct user operation. More specifically, the power receiving device 200 is a pet robot that mimics a small animal. The power receiving device 200 includes a main body 210 and an outer casing 220. The main body 210 contains various components necessary for the operation of the power receiving device 200. For example... Figure 2 As shown, the main body 210 includes a head 211, a connecting part 212, and a torso 213. Figure 2 This diagram schematically illustrates the cross-section of the power supply device 100 and the power receiving device 200 in their stored state when cut along a plane extending in the long and vertical directions of the storage section 110.

[0025] In addition, Figure 2 For ease of understanding, the external mounting part 220 of the power receiving device 200 is omitted from the illustration; only the main body 210 is shown. Additionally, in Figure 2 For ease of understanding, the shading of the cross-section is omitted. The head 211 corresponds to the head of a small animal. The connecting part 212 is the part that rotatably connects the head 211 to the torso 213. The torso 213 corresponds to the torso of a small animal. A receiving coil 230 and a magnetic sensor 250 are disposed inside the main body 213. The outer garment 220 is the part that covers the main body 210. The outer garment 220 has decorative parts that mimic eyes and fluffy fur. The fabric of the outer garment 220 is, for example, formed of artificial napped fabric that mimics the skin feel of a small animal. The lining of the outer garment 220 is, for example, formed of fibers, leather, rubber, etc. The outer garment 220 is formed of a soft material, so the outer garment 220 can follow the movement of the main body 210.

[0026] Furthermore, the receiving device 200 can be automatically or manually stored in the storage compartment 110. For example, the receiving device 200 can automatically move into the storage compartment 110 in response to the remaining battery power falling below a certain threshold. Alternatively, the user can store the receiving device 200 in the storage compartment 110 upon receiving a notification from the receiving device 200 indicating that the remaining battery power is low. This notification is issued by the receiving device 200 in response to the remaining battery power falling below a certain threshold.

[0027] like Figure 2As shown, when the power receiving device 200 is housed in the storage section 110, the magnetic sensor 250 approaches the magnet 150, and the magnetic field emitted by the magnet 150 can be detected by the magnetic sensor 250. In addition, when the power receiving device 200 is housed in the storage section 110, the power supply coil 130 approaches and faces the power receiving coil 230, and power can be supplied to the power receiving device 200 from the power supply device 100.

[0028] like Figure 3 As shown, the power supply device 100 includes a power supply coil 130, a coil cover 131, a heat-conducting member 132, a heat-conducting double-sided tape 133, a base 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 supply coil 130. The upper surface of the coil cover 131 is a mounting surface 131A for mounting the power receiving device 200. The coil cover 131 is formed of a material that does not generate heat when powered by the power supply coil 130. For example, the coil cover 131 is made of plastic. The coil cover 131 is an example of a mounting portion. The heat-conducting member 132 is attached to the lower surface of the coil cover 131 using the heat-conducting double-sided tape 133. The heat-conducting member 132 is formed of a component with high thermal conductivity. For example, the heat-conducting member 132 is formed of an acrylic-based material, a silicone-based material, etc. The heat-conducting double-sided tape 133 is a double-sided tape formed of a component with high thermal conductivity. For example, thermally conductive double-sided tape 133 is formed by coating both sides of a polyetheretherketone resin film, polyethylene terephthalate film, etc., with an acrylic adhesive with high thermal conductivity.

[0029] The base 134 is a component that supports the power supply coil 130. The power supply coil 130 is disposed on the upper surface of the base 134. The base 134 is formed of an insulating material, such as plastic. The substrate 135 is a printed circuit board on which various electronic components are mounted. Power supply circuits, control circuits, etc., are mounted on the substrate 135. The temperature sensor 140 is a sensor that detects the temperature of the heat conduction component 132. The temperature sensor 140 is a contact-type temperature sensor such as a temperature-sensing resistor, a linear resistor, or a thermistor. The temperature sensor 140 is disposed at the lower center of the heat conduction component 132. The temperature sensor 140 is mounted on the flexible printed wiring board 143 and housed within a through hole (not shown) provided in the pressing member 142. Temperature information indicating the temperature detected by the temperature sensor 140 is transmitted to the electronic components mounted on the substrate 108 via the flexible printed wiring board 143.

[0030] The pressing member 142 is used to press the printed wiring board 143 onto the heat conduction member 132 using the force applied from the base 134. The pressing member 142 is formed of an elastic member, such as 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 receiving the temperature sensor 140. By pressing the member 142, the printed wiring board 143 can be pressed onto 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 electronic components on the substrate 108. The flexible printed wiring board 143 is, for example, a wiring board on which a circuit pattern is formed on a resin film with high thermal conductivity. When a foreign object present on the coil cover 131 heats up due to power supply, the heat emitted by the foreign object is transferred 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 this embodiment, the foreign object is a metallic foreign object that generates heat according to changes in magnetic flux.

[0031] Temperature sensor 140 is disposed at the lower center of heat conduction member 132. Therefore, heat emitted by foreign objects can be efficiently detected regardless of their location on the coil cover 131. Furthermore, the heat conduction member 132 diffuses the heat generated by the foreign object, thus mitigating its temperature rise. Additionally, 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, preventing the transfer of heat generated by the foreign object to the receiving device 200.

[0032] Figure 4 The power transmission system 1000 shown includes a power supply unit 100 and a power receiving device 200. The power supply unit 100 includes a power transmitting 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 includes 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 transmitting coil 130 is a coil coupled to the power receiving coil 230 and is used for wireless power supply. The power transmitting coil 130 induces a changing magnetic flux through the flow of alternating current. The power transmitting coil 130 is a wire wound around an axis extending along the Z-axis. The power transmitting coil 130 is positioned in a predetermined location within the power supply unit 100 such that, in the retracted state, the power transmitting coil 130 faces the power receiving coil 230. In the stowed state, the central axis of the receiving coil 230 is close to the central axis of the sending coil 130.

[0033] Temperature sensor 140 detects the temperature of a predetermined location within the power supply unit 100. In this embodiment, temperature sensor 140 detects the temperature of heat conduction member 132. Furthermore, if a foreign object containing metal is present around the power supply coil 130, eddy currents flow through the foreign object due to changes in the magnetic flux induced by the power supply coil 130, causing the foreign object to heat up. Temperature sensor 140 is primarily used to detect this heating of the foreign object. Temperature sensor 140 supplies temperature information, representing the detected temperature, to control circuit 170. Temperature sensor 140 is an example of a temperature detection unit. Heat conduction member 132 is an example of a predetermined location.

[0034] Magnet 150 is an object that emits magnetism. Magnet 150 has two poles, N and S, and is an object that generates a bipolar magnetic field. Magnet 150 is disposed in a specific location within 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 protrusion 113. Magnet 150 is positioned and angled to correspond to the position and angle of the magnetic sensor 250. That is, magnet 150 is positioned and angled so that the magnetic field emitted by magnet 150 can be detected by the magnetic sensor 250 in the retracted state. In this embodiment, magnet 150 is a permanent magnet.

[0035] Power transmission circuit 160 is a circuit for supplying power to power receiving device 200. Power transmission circuit 160 is a circuit for wirelessly supplying power via power transmission coil 130. Power transmission circuit 160 supplies AC power, based on DC power supplied from power supply circuit 180, to power transmission coil 130. Power transmission circuit 160 operates under the control of control circuit 170. Power transmission circuit 160 communicates with power receiving circuit 260. Specifically, power transmission circuit 160 begins supplying power to power receiving circuit 260 upon receiving a power supply request from power receiving circuit 260. Power transmission circuit 160 includes power transmission IC 161. Power transmission IC 161 converts DC power generated by power supply circuit 180 into AC power and supplies the AC power to power transmission coil 130. Power transmission circuit 160 is an example of a power supply unit. Control circuit 170 controls the overall operation of power supply device 100. For example, control circuit 170 controls power transmission circuit 160 to supply power to power receiving device 200. The control circuit 170 controls the power supply to the powered device 200 based on the detection results of the temperature sensor 140. The control circuit 170 can also notify the powered device 200 of any detected anomaly, causing the powered device 200 to report the presence of an anomaly. Such anomalies include excessive temperature rise accompanied by foreign objects or positional displacement, and decreased transmission efficiency accompanied by positional displacement. The control circuit 170 is an example of a control unit.

[0036] The control circuit 170 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), RTC (Real Time Clock), and flash memory. The CPU, also known as a central processing unit, central arithmetic unit, processor, microprocessor, microcomputer, or DSP (Digital Signal Processor), functions as the central processing unit responsible for executing the processing and calculations involved in controlling the control circuit 170. In the control circuit 170, the CPU reads programs and data stored in ROM, flash memory, etc., uses RAM as its working area, and performs unified control of the control circuit 170. The RTC integrated circuit is, for example, an integrated circuit with a timing function. Furthermore, the CPU can determine the current date and time based on the time information read from the RTC.

[0037] 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 boosts the DC voltage supplied from the AC adapter 190 to generate the power supply voltages for each component 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 a commercial power source into DC power and supplies the DC power to the power supply circuit 180. The AC adapter 190 has a DC plug 191 that connects to the power supply circuit 180. The receiving coil 230 is a coil coupled to the transmitting coil 130 and is used to wirelessly receive power. The receiving coil 230 induces an electromotive force based on the change in magnetic flux induced by the transmitting coil 130. The receiving coil 230 is a wire wound around an axis extending along the Z-axis.

[0038] Sensor 241 is a sensor used to detect various physical quantities. As sensor 241, touch sensors, acceleration sensors, angular velocity sensors, sound sensors, illuminance sensors, temperature sensors, etc., can be considered. For example, a touch sensor detects when a user touches the outer casing 220. An acceleration sensor detects, for example, the acceleration applied to the entire or a part of the powered device 200. An angular velocity sensor detects, for example, the angular velocity of the entire or a part of the powered device 200. A sound sensor detects, for example, the sound emitted by the user. An illuminance sensor detects, for example, the illuminance around the powered device 200. A temperature sensor detects, for example, the internal or external temperature of the powered device 200. Sensor 241 supplies an electrical signal indicating the detection result to control circuit 270. Actuator 242 is a mechanism for actuating various parts of the powered device 200. Actuator 242 operates according to the control of control circuit 270. For example, actuator 242 is a mechanism for moving the powered device 200 forward or backward in a longitudinal direction or for rotating the head 211 relative to the torso 213. Actuator 242 may include, for example, a stepper motor.

[0039] The speaker 243 emits sound under the control of the control circuit 170. For example, if the power supply device 100 detects an abnormality, the speaker 243 outputs a sound indicating that an abnormality has been detected, based on the sound signal supplied from the control circuit 170. The magnetic sensor 250 is a sensor that detects magnetism. The magnetic sensor 250 detects the magnetism emitted by the magnet 150 located at a specific part of the power supply device 100. The magnetic sensor 250 outputs a first voltage when magnetism is detected and a second voltage when magnetism is not detected. The voltage output by the magnetic sensor 250 is applied to the operation control terminal 262 of the powered IC 261. As described later, power supply is allowed when magnetism is detected and not allowed when magnetism is not detected. Furthermore, the magnetic sensor 250 is configured to not detect the position or angle of the magnetism generated by the power supply coil 130.

[0040] The receiving circuit 260 is a circuit for wirelessly receiving power via the receiving coil 230. The receiving circuit 260 supplies DC power, based on AC power supplied from the power supply device 100 via the receiving coil 230, to the storage battery 280. The receiving circuit 260 operates under the control of the control circuit 270. The receiving circuit 260 communicates with the power supply circuit 160. For example, in order to receive power from the power supply circuit 160, the receiving circuit 260 sends a power request to the power supply circuit 160. The receiving circuit 260 includes a receiving IC (Integrated Circuit) 261. The receiving IC 261 converts AC power generated by the electromotive force induced by the receiving coil 230 into DC power and supplies the DC power to the storage battery 280. The receiving IC 261 includes an operation control terminal 262 for controlling the operation of the receiving IC 261. The 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.

[0041] When a first voltage is applied to the operation control terminal 262, the powered IC 261 operates. Therefore, the powered circuit 260 sends a power supply request to the power supply circuit 160, supplying power to the power supply device 100. Conversely, when a second voltage is applied to the operation control terminal 262, the powered IC 261 stops operating. Therefore, the powered circuit 260 does not send a power supply request to the power supply circuit 160 and does not supply power to the power supply device 100. The control circuit 270 controls the overall operation of the powered device 200. For example, the control circuit 270 activates the actuator 242 based on the detection result of the sensor 241, thereby activating the powered device 200. Furthermore, upon receiving a notification from the power supply device 100 indicating that an anomaly has been detected, the control circuit controls the speaker 243 to notify the user of the detected anomaly. The control circuit 270 includes a CPU, ROM, RAM, RTC, flash memory, etc.

[0042] Battery 280 is a rechargeable and dischargeable secondary battery. Battery 280 is the power source for the power receiving device 200. That is, battery 280 supplies power to sensors 241, actuators 242, magnetic sensors 250, power receiving circuits 260, control circuits 270, etc. Additionally, battery 280 is charged by the power supplied from power receiving circuits 260. Control circuit 170 controls the power supply from power supply circuit 160 to the power receiving device 200 based on the temperature detected by temperature sensor 140 (i.e., the detection temperature and the reference temperature).

[0043] The control circuit 170 interrupts power supply when it detects that the temperature has risen to the interruption temperature during power supply. The control circuit 170 restarts power supply when it detects that the temperature has dropped to the restart temperature during the 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 restarted. Both the interruption temperature and the restart temperature are set based on a reference temperature. The reference temperature is essentially the temperature detected at the start of power supply. The interruption temperature is a temperature that is a first predetermined temperature higher than the reference temperature. The restart temperature is a second predetermined temperature lower than the interruption temperature. In this embodiment, the first predetermined temperature is 20°C, and the second predetermined temperature is 5°C. That is, the temperature difference between the reference temperature and the restart temperature is set to be smaller than the temperature difference between the reference temperature and the interruption temperature. Furthermore, the restart temperature is set to be higher than the reference temperature.

[0044] If, at the start of power supply, a first predetermined time has elapsed since the last power supply ended, and the rate of change of the detected temperature during a predetermined period before power supply begins is within a reference value, 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, a first predetermined time has elapsed since the last power supply ended, and the rate of change is not within the reference value, the control circuit 170 does not update the reference temperature. Furthermore, if, at the start of power supply, a first predetermined time has not elapsed since the last power supply ended, the control circuit 170 does not update the reference temperature. The first predetermined time is a time shorter than the time required for the detected temperature, which is considered to have decreased due to power supply. The first predetermined time is, for example, 2 minutes. The predetermined period is the period during which the rate of change of the detected temperature is calculated. The predetermined period is, for example, 2 minutes before power supply begins.

[0045] The rate of change corresponds to the magnitude of the change in detected temperature during the specified period. The definition of the rate of change can be appropriately adjusted. For example, the rate of change can also be the slope of a straight line approximating the detected temperature in a graph representing the detected temperature and time during the specified period. That is, the rate of change can also be the slope of the regression line (i.e., the regression coefficient) when performing a regression analysis with the detected temperature during the specified period as the target variable and the detection time of the detected temperature as the explanatory variable. Alternatively, the rate of change can 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 can also be the value obtained by dividing the temperature difference between the highest and lowest detected temperatures during the specified period by the length of the specified period. A benchmark value is a threshold used to determine the rate of change. For example, assuming the detected temperature continuously decreases during the specified period, the ratio of the decrease in detected temperature to the length of the specified period is set as the rate of change. Furthermore, the length of the specified period is set to 2 minutes, and the benchmark value is set to 2.5℃ / minute. In this case, the reference temperature is updated if the detected temperature does not decrease by more than 5°C within the specified period, and is not updated if the detected temperature decreases by more than 5°C within the specified period.

[0046] Thus, the control circuit 170 updates the reference temperature to the current detection temperature only when the most recent detection temperature stabilizes, provided that a certain amount of time has elapsed since the last power supply. Furthermore, the control circuit 170 does not update the reference temperature if not much time has elapsed since the last power supply. The control circuit 170 terminates power supply when the detected temperature rises to a predetermined upper limit temperature during power supply. That is, regardless of the comparison result between the detected temperature and the interruption temperature, the control circuit 170 terminates power supply when the detected temperature reaches the upper limit temperature. In this embodiment, the upper limit temperature is 60°C.

[0047] like Figure 5 As shown, consider the following scenario: the reference temperature has not been updated, and at t10, the powered device 200 is set to the power supply unit 100 and begins supplying power. Here, during a predetermined period prior to the start of power supply, i.e., from t11 to t10, the detected temperature remains constant. In this case, the variation range of the detected temperature during the predetermined period is 0°C, and the rate of change of the detected temperature during the predetermined period is less than or equal to the reference value. Furthermore, the elapsed time since the last power supply termination is greater than or equal to the first reference time. In this case, the reference temperature is updated to the current detected temperature. Figure 5In this diagram, d1 is the upper limit temperature, d10 is the detection temperature at t10, d11 is the detection temperature at t11, D11 is the change range, D1 is the reference range, T11 is the elapsed time from the last power supply end time to t10, T1 is the length of the first specified time, and T2 is the length of the specified period. Furthermore, the reference range is the threshold for the change range of the detected temperature, which is the temperature difference corresponding to a reference value for the rate of change. That is, a change range of the detected temperature greater than or equal to the reference range corresponds to a rate of change of the detected temperature greater than or equal to the reference value. For example, if the length of the specified period is 2 minutes and the reference value is 2.5°C / minute, then D1, as the reference width, is 5°C. At time t10, the reference temperature is set to the current detection temperature, i.e., d10. The interrupt temperature is set to a temperature D2 higher than the reference temperature, i.e., d12. The restart temperature is set to a temperature D3 lower than the interrupt temperature, i.e., d13. Information representing the reference temperature, interrupt temperature, restart temperature, etc., is stored, for example, in the flash memory provided by the control circuit 170.

[0048] Thus, in this embodiment, the interruption temperature, restart temperature, etc., are variable values ​​set based on the detected temperature, not fixed values. The reason for this is that it is considered best to determine the interruption and restart of power supply based on the amount of temperature rise caused by power supply, rather than on the detected temperature itself. According to this structure, for example, immediate power supply interruption is suppressed when the room temperature is high, and excessive temperature rise caused by power supply is suppressed when the room temperature is low. In contrast, if the interruption temperature, restart temperature, etc., are fixed values, for example, it is possible for the power supply to be interrupted immediately when the room temperature is high, and for excessive temperature rise caused by power supply to occur when the room temperature is low. When power supply starts at t10, the detected temperature rises. Basically, the detected temperature rises during power supply. However, in the presence of foreign objects, the detected temperature rises sharply. Furthermore, when the positions of the power supply coil 130 and the receiving coil 230 are significantly offset, the detected temperature rises sharply. Here, at t12, when the detected temperature rises to d12, which is the interruption temperature, the power supply is interrupted.

[0049] When power is interrupted at t12, the detected temperature decreases. When the detected temperature decreases to d13 (the restart temperature) at t13, power is restarted. When power is restarted at t13, the detected temperature rises. Thereafter, similarly, power is interrupted when the detected temperature rises to the interruption temperature and restarted when the detected temperature decreases to the restart temperature. Here, at t14, power supply ends when the powered device 200 is removed from the power supply unit 100. When power supply ends at t14, the detected temperature decreases. At t20, power supply begins when the powered device 200 is placed back into the power supply unit 100.

[0050] Furthermore, in this embodiment, the distinction between the end and interruption of power supply, and the distinction between the start and restart of power supply, are clearly defined. Specifically, the cessation of power supply caused by the removal of the powered device 200, full charging, or the detection temperature reaching the upper limit temperature is referred to as the end of power supply, and the cessation of power supply caused by the detection temperature reaching the interruption temperature is referred to as the interruption of power supply. Additionally, the start of power supply caused by the installation of the powered device 200 is referred to as the start of power supply, and the start of power supply caused by the detection temperature reaching the restart temperature is referred to as the restart of power supply. T21 is the time length from t14 to t20, d21 is the detection temperature at t21, d20 is the detection temperature at t20, and D21 is the temperature difference between d21 and d20. When T21 is above T1, if D21 is greater than D1, the reference temperature is not updated. That is, the reference temperature is not updated to the detection temperature at t20 (d20), but remains at the detection temperature at t10 (d10). Therefore, the interruption temperature is also maintained at d12, and the restart temperature is also maintained at d13. Subsequently, when power is supplied in t20, the temperature rises. When the temperature rises to d12 (the interruption temperature) in t22, the power supply is interrupted. Conversely, when power is interrupted in t22, the temperature decreases. When the temperature drops to the restart temperature d13 in t23, the power supply is restarted.

[0051] Next, refer to Figure 6 An example of updating the reference temperature is provided. t11 to t14 are as follows: Figure 5 As explained. At t30, power supply begins when the powered device 200 is placed back onto the power supply unit 100. T31 is the length of time from t14 to t30, d31 is the detection temperature at t31, d30 is the detection temperature at t30, and D31 is the temperature difference between d31 and d30. If T31 is above T1, and D31 is below D1, the reference temperature is updated from d10 (the detection temperature at t10) to d30 (the detection temperature at t30). Furthermore, the interruption temperature is updated to d32, which is D2 higher than d30. The restart temperature is updated to d33, which is D3 lower than d32. Subsequently, if power supply begins at t30, the detection temperature rises; if the detection temperature rises to d32 (the interruption temperature) at t32, power supply is interrupted. Conversely, if power supply is interrupted at t32, the detection temperature decreases; if the detection temperature decreases to d33 (the restart temperature) at t33, power supply is restarted.

[0052] Thus, if a first reference time or more has elapsed since the last power supply ended when power supply begins, and the rate of change of the detected temperature during the specified period before power supply begins is less than the reference value, the reference temperature is updated. Conversely, if a first specified time or more has elapsed since the last power supply ended when power supply begins, and the rate of change of the detected temperature during the specified period before power supply begins 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 too high. That is, as described above, if the powered device 200 is immediately replaced after power supply is terminated by removing it, the detected temperature at the start of power supply is higher than normal temperature. Therefore, if the detected temperature at the start of power supply is set as the reference temperature, the interruption temperature is set too high. In particular, if the powered device 200 is repeatedly replaced during power supply, the reference temperature, interruption temperature, etc., are set too high.

[0053] However, setting the interruption temperature to an excessively high temperature would allow for power supply at high temperatures, which is not preferable. Therefore, if more than a first reference time has elapsed since the last power supply ended when power supply begins, and the aforementioned rate of change is greater than the reference value, the reference temperature is not updated, and the previously set reference temperature is maintained. Furthermore, if power supply begins immediately after power supply ends, it is assumed that the detected temperature is decreasing, and the aforementioned rate of change is large. In other words, if the aforementioned rate of change is small at the start of power supply, it is assumed that the detected temperature has decreased to room temperature, rather than immediately after power supply ends. Therefore, in this embodiment, the detection temperature is sufficiently decreased by detecting cases where the rate of change is small. Furthermore, if it is clearly the case that power supply has just ended, that is, if no first reference time has elapsed since the last power supply ended, the reference temperature is not updated.

[0054] Next, as Figure 7The power management process performed by the power supply device 100 will be described below. First, the control circuit 170 of the power supply device 100 detects the temperature (step S101). For example, the control circuit 170 obtains temperature information indicating the temperature detected by the temperature sensor 140. When completing step S101, the control circuit 170 determines whether the device 200 is activated (step S102). For example, the control circuit 170 sends a signal to the device 200 using the power supply circuit 160, and if the device 200 responds to the signal, it determines that the device 200 is activated. When completing step S102, the control circuit 170 determines whether a first predetermined time has elapsed since the last power supply ended (step S103). Furthermore, the control circuit 170 can determine the last power supply end time by referring to the power supply end time information stored in the flash memory of the control circuit 170. Power supply end time information is information indicating when power supply ends, such as information stored in flash memory whenever power supply ends.

[0055] When control circuit 170 determines that more than a first predetermined 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, control circuit 170 determines whether the difference between the maximum value of the detected temperature and the minimum value of the detected temperature in the most recent predetermined period is less than a reference range. If control circuit 170 determines that the rate of change of the detected temperature is within the reference value (step S104: Yes), it sets the detected temperature to the reference temperature (step S105). That is, control circuit 170 updates the reference temperature to the current detected temperature. When control circuit 170 completes the processing of step S105, it sets the interrupt temperature and restart temperature based on the reference temperature (step S106).

[0056] The control circuit 170 executes power supply control processing (step S107) if it determines that no more than a first predetermined time has elapsed since the last power supply ended (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 processing in step S106. Hereinafter, refer to... Figure 8The flowchart shown illustrates the power supply control process. First, control circuit 170 starts supplying power (step S201). For example, control circuit 170 starts supplying power to the receiving device 200 via power supply circuit 160. While completing step S201, control circuit 170 detects the temperature (step S202). While completing step S202, control circuit 170 determines whether it is currently supplying power (step S203). If control circuit 170 determines that it is supplying power (step S203: Yes), it determines whether the detected temperature has reached the interruption temperature (step S204). If control circuit 170 determines that the detected temperature has reached the interruption temperature (step S204: Yes), it interrupts the power supply (step S205). That is, control circuit 170 controls power supply circuit 160 to temporarily stop supplying power to the receiving device 200.

[0057] When the control circuit 170 determines that it is not supplying power (step S203: No), it determines whether the detected temperature has reached the restart temperature (step S206). When the control circuit 170 determines that the detected temperature has reached the restart temperature (step S206: Yes), it restarts the power supply (step S207). That is, the control circuit 170 controls the power supply circuit 160 to start supplying power to the powered device 200 again. When the control circuit 170 determines that the detected temperature has not reached the interruption temperature (step S204: No), when it determines that the detected temperature has not reached the restart temperature (step S206: No), or when it has completed the processing of step S205 or step S207, it determines whether the powered device 200 is fully charged (step S208). For example, when the control circuit 170 receives a signal indicating that the powered device 200 is fully charged from the powered device 200, it determines that the powered device 200 is fully charged.

[0058] When control circuit 170 determines that the powered device 200 is not fully charged (step S208: "No"), it determines whether the removal of the powered device 200 has been detected (step S209). When control circuit 170 determines that the removal of the powered device 200 has not been detected (step S209: "No"), it determines whether the detection temperature has reached the upper limit temperature (step S210). When control circuit 170 determines that the detection temperature has not reached the upper limit temperature (step S210: "No"), it returns the process to step S202. If 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 detection temperature has reached the upper limit temperature (step S210: "Yes"), it terminates the power supply (step S211). When control circuit 170 completes the process of 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 the process to step S101.

[0059] In this embodiment, if a first predetermined time or more has elapsed since the last power supply ended when power supply begins, and the rate of change of the detected temperature during the predetermined period before power supply begins 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 power supply control is set to prevent it from becoming too high. 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 an interruption temperature based on the reference temperature during power supply, power supply is interrupted; if the detected temperature drops to a restart temperature based on the reference temperature during the power supply interruption, power supply is restarted. According to this embodiment, appropriate power supply with the detected temperature not exceeding the interruption temperature can be achieved.

[0060] Furthermore, in this embodiment, power supply ends when the detected temperature rises to a predetermined upper limit temperature during power supply. According to this embodiment, excessive temperature rise caused by power supply can be reliably suppressed. Additionally, in this embodiment, the temperature of the heat conduction member 132 disposed between the power receiving device 200 and the power supply coil 130 when the power receiving device 200 is placed on the mounting surface 131A is detected as the detection temperature. According to this embodiment, appropriate power supply based on the detection temperature can be achieved in contactless power supply.

[0061] Next, Embodiment 2 will be described. In Embodiment 1, the temperature difference between the detected temperature and the reference temperature at the start of power supply is not considered. In contrast, in this embodiment, the temperature difference between the detected temperature and the reference temperature at the start of power supply is considered. Furthermore, descriptions of structures and functions identical to those in Embodiment 1 are appropriately omitted or simplified. In this embodiment, if a first predetermined time has elapsed since the last power supply ended 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 control circuit 170 updates the reference temperature to the detected temperature at the start of power supply. That is, if a first predetermined time has elapsed since the last power supply ended at the start of power supply, and even if the rate of change is within a reference value, the control circuit 170 does 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 a temperature difference threshold.

[0062] For example, in Figure 6In this diagram, 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 predetermined time, D1 is the reference width, and D4 is the temperature difference threshold. Furthermore, at time t30, the reference temperature is d10. If T31 is greater than or equal to T1, and 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. Conversely, if T31 is greater than or equal to T1, and D31 is less than or equal to D1 and D32 is greater than D4, the reference temperature is not updated.

[0063] The reason for considering the temperature difference between the detected temperature and the reference temperature at the start of power supply is to further suppress setting an excessively high reference temperature. For example, if power supply begins immediately after the previous power supply has ended, the detected temperature may not decrease significantly for some reason just before power supply begins. In this case, if the temperature difference between the detected temperature and the reference temperature at the start of power supply is not considered, the excessively high detected temperature will be set as the reference temperature. On the other hand, if the temperature difference between the detected temperature and the reference temperature at the start of power supply is considered, the setting of an excessively high detected temperature as the reference temperature will be prevented. For example, even if power supply begins when the detected temperature remains high for some reason, it is possible to prevent the reference temperature from being updated to the detected temperature at which it has stopped rising. Furthermore, a temperature difference between the detected temperature and the reference temperature at the start of power supply that is below a temperature difference threshold essentially means that the current detected temperature has decreased to near the detected temperature at the start of the previous power supply.

[0064] The following is for reference. Figure 9The flowchart shown illustrates the power management process performed by the power supply device 100. Steps S101 to S103 are processed as described in Embodiment 1. When the control circuit 170 determines that more than a first predetermined time has elapsed since the last power supply ended (Step S103: Yes), it determines whether the change in the detected temperature is within a reference value (Step S104). When the control circuit 170 determines that the change in the detected temperature is within a reference range (Step S104: Yes), it determines whether the temperature difference between the detected temperature and the reference temperature is below a temperature difference threshold (Step S104A). When it determines that the temperature difference between the detected temperature and the reference temperature is below a temperature difference threshold (Step S104A: Yes), it sets the detected temperature to the reference temperature (Step S105). After completing the processing in Step S105, the control circuit 170 sets the interruption temperature and restart temperature based on the reference temperature (Step S106). If the control circuit 170 determines that no more than a first predetermined time has elapsed since the last power supply ended (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, it executes the power supply control processing (step S107).

[0065] In this embodiment, if a first predetermined time or more has elapsed since the last power supply ended 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, setting 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.

[0066] Next, Embodiment 3 will be described. In Embodiment 1, power supply control is applied to contactless power supply; in contrast, in Embodiment 3, power supply control is applied to contact power supply. Furthermore, descriptions of structures and functions identical to those in Embodiments 1 and 2 will be appropriately omitted or simplified. Figure 10 As shown, the power transmission system 1000A of this embodiment includes a power supply device 100A, a power receiving device 200A, and a power supply cable 300. The power supply device 100A includes 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 includes 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.

[0067] Connector 136 is a connector at one end of the connecting cable 300. Connector 136 is connected to a power supply circuit 160A. The power supply circuit 160A is a circuit for supplying power to a powered device 200A via the power supply cable 300. The power supply circuit 160A, for example, supplies DC power based on DC power supplied from the power supply circuit 180 to the powered device 200A via the power supply cable 300. The power supply circuit 160A includes a power supply IC 161A. The power supply IC 161A converts the DC power generated by the power supply circuit 180 into the desired DC power. Connector 236 is a connector at the other end of the connecting cable 300. Connector 236 is connected to a powered circuit 260A. The powered circuit 260A is a circuit for receiving power from a power supply device 100A via the power supply cable 300. The powered circuit 260A, for example, supplies DC power based on DC power supplied from the power supply device 100A via the power supply cable 300 to a storage battery 280. 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 the desired DC power.

[0068] Temperature sensor 140 detects the temperature of a predetermined location in the power supply device 100A. For example, temperature sensor 140 detects the temperature around the power supply circuit 160A. Temperature sensor 140 supplies temperature information, representing the detected temperature, to control circuit 170. Control circuit 170 performs power supply control based on the detected temperature represented by the temperature information. The power supply control in this embodiment is basically the same as the power supply control in embodiment 1. Power supply circuit 160A is an example of a predetermined location. If the control circuit 170 detects that the temperature rises to an interruption temperature based on a reference temperature during power supply, it interrupts the power supply. If the control circuit 170 detects that the temperature drops to a restart temperature based on a reference temperature after the power supply interruption, it restarts the power supply. If, at the start of power supply, more than a first predetermined time has elapsed since the last power supply ended, and the rate of change of the detected temperature during a predetermined period before the start of power supply is within a reference value, the control circuit 170 updates the reference temperature to the detected temperature at the start of power supply.

[0069] According to this embodiment, essentially the same effects as in Embodiment 1 can be achieved. That is, in this embodiment, it is also possible to prevent the reference temperature for power supply control from being set too high. Therefore, according to this embodiment, appropriate power supply based on the detected temperature can also be achieved.

[0070] The embodiments have been described above, but various modifications and applications are possible. The choice of which part of the structure, function, or operation described in the above embodiments is arbitrary. Furthermore, in addition to the structures, functions, and operations described above, further structures, functions, and operations may be employed. Moreover, the structures, functions, and operations described in the above embodiments can be freely combined. In Embodiment 1, an example was described of setting the interruption temperature and restart temperature based on a reference temperature, and controlling the power supply based on the interruption temperature and restart temperature. It is also possible to set the end temperature based on the reference temperature and control the power supply based on the end temperature. For example, if the detected temperature rises to the end temperature, the power supply may end without interruption.

[0071] In Embodiment 1, an example was described where power supply to the powered device 200 was stopped when it was detected that the powered device 200 was fully charged. Even when the powered device 200 is detected to be fully charged, the power supply level can be reduced compared to normal power supply, while continuing to supply power to the powered device 200. In this case, it is also preferable to interrupt the power supply in response to the detected temperature reaching the interruption temperature, and to restart the power supply in response to the detected temperature reaching the restart temperature.

[0072] In Embodiment 1, an example is described where, even if sufficient time has elapsed since the last power supply, the rate of change of the detected temperature during a predetermined period before the power supply begins exceeds a reference value, the reference temperature is not updated. However, if sufficient time has elapsed since the last power supply, the detected temperature has sufficiently decreased, and it is considered that the detected temperature has stabilized at approximately room temperature. In this case, it is considered that even if the reference temperature is updated to the detected temperature, the possibility of the reference temperature being set too high is low. Therefore, the control circuit 170 can also 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 predetermined period before the power supply begins, if a second predetermined time or more has elapsed since the end of the last power supply at the start of power supply, which is longer than the first predetermined time. That is, the control circuit 170 updates the reference temperature to the detected temperature at the start of power supply when it considers that sufficient time has elapsed since the last power supply and the detected temperature has stabilized at approximately room temperature. The second predetermined time is the time required for the detected temperature, which has risen due to power supply, to sufficiently decrease. According to this structure, appropriate power supply based on the detected temperature and an appropriate reference temperature can be achieved.

[0073] In Embodiment 1, an example of a robot mimicking a small animal was described as the power receiving device 200. The power receiving device 200 can be other robots or devices other than robots. For example, the power receiving device 200 can also be a smartphone, electronic dictionary, gaming device, etc. This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of this disclosure. Furthermore, the above embodiments are illustrative of this disclosure and do not limit its scope. That is, the scope of this disclosure is not indicated by the embodiments, but by the claims. Moreover, various modifications implemented within the scope of the claims and their equivalents are considered to be within the scope of this disclosure.

Claims

1. A power supply device, characterized in that, have: The power supply department supplies power to the receiving equipment; The temperature detection unit detects the temperature of a predetermined location; and The control unit controls the power supply unit to supply power to the powered device based on the temperature detected by the temperature detection unit (i.e., the detected temperature) and the reference temperature. If, at the start of power supply, more than a first predetermined time has elapsed since the end of the last power supply, and if the rate of change of the detected temperature during the predetermined period before 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.

2. The power supply device according to claim 1, wherein, The control unit interrupts power supply when the detected temperature rises to an interruption temperature based on the reference temperature during power supply, and restarts power supply when the detected temperature drops to a restart temperature based on the reference temperature during power supply interruption.

3. The power supply device according to claim 1 or 2, wherein, If, at the start of the power supply, more than the first predetermined time has elapsed since the end of the last power supply, the control unit updates the reference temperature to the detection temperature at the start of the power supply when the rate of change is within the reference value and the temperature difference between the detected temperature at the start of the power supply and the reference temperature is below a temperature difference threshold.

4. The power supply device according to claim 1 or 2, wherein, If, at the start of the power supply, more than the first predetermined time has elapsed since the end of the last power supply, and the temperature difference between the detected temperature and the reference temperature at the start of the power supply exceeds a temperature difference threshold, the control unit will not update the reference temperature and will maintain it even if the rate of change is within the reference value.

5. The power supply device according to claim 1 or 2, wherein, If, at the start of the power supply, a second predetermined time or longer than the first predetermined time has elapsed since the end of the last power supply, the control unit updates the reference temperature to the detected temperature at the start of the power supply, regardless of the rate of change.

6. The power supply device according to claim 1 or 2, wherein, If, at the start of the power supply, no more than the first predetermined time has elapsed since the end of the last power supply, the control unit does not update the reference temperature but maintains it.

7. The power supply device according to claim 1 or 2, wherein, The restart temperature is set to a temperature higher than the reference temperature.

8. The power supply device according to claim 7, wherein, The temperature difference between the reference temperature and the restart temperature is set to be smaller than the temperature difference between the reference temperature and the interruption temperature.

9. A power supply method, characterized in that, This includes the following processing: Detect the temperature at a designated location; The power supply to the powered device is controlled based on the detected temperature and the reference temperature; and If, at the start of power supply, more than a first predetermined time has elapsed since the end of the last power supply, and if the rate of change of the detected temperature during the predetermined period before 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.

10. A computer program product, characterized in that, A computer equipped with a power supply unit that supplies power to a power-receiving device and a temperature detection unit that detects the temperature of a predetermined location performs the following function: based on a reference temperature and the detected temperature by the temperature detection unit, it controls the power supply unit to supply power to the power-receiving device. If, at the start of power supply, more than a first predetermined time has elapsed since the end of the last power supply, and the rate of change of the detected temperature during a predetermined period before the start of power supply is within a reference value, the function updates the reference temperature to the detected temperature at the start of power supply.

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