Method and device for estimating temperature of contents in electric pot

Abstract

[Problem] To quickly and accurately estimate a constantly changing heating temperature of water or other contents accommodated in an electric pot by using the temperature of a heater without directly measuring the temperature of the contents. [Solution] A device for heating contents 36 using a built-in heater 18 by receiving power from a power-supplying coil 13 of a power supply stand 27 in a contactless manner using a power-receiving coil 14 of an electric pot 28, wherein the device comprises: a power supply circuit 19 for supplying power to the heater 18; a temperature sensor 22 for detecting the temperature of the heater 18; a control unit 20 for controlling energization of the heater 18; a temperature storage unit 25 for storing, via the control unit 20, the temperature detected by the temperature sensor 22; a temperature estimation coefficient storage unit 29 for storing a preset unique temperature estimation coefficient Ce of the electric pot 28; and a temperature estimation unit 26 for estimating the temperature of the contents 36 on the basis of the data in the temperature storage unit 25 and the temperature estimation coefficient Ce.

Description

Method and device for estimating temperature of contents in an electric kettle

[0001] The present invention relates to a method and apparatus for estimating the temperature of contents in an electric kettle, which accurately estimates the heating temperature of the contents based on a temperature sensor of a heater built into the electric kettle.

[0002] A conventional electric kettle is known, as shown in Fig. 7 (Patent Document 1). In Fig. 7, an annular heater 52 is provided as heating means on the outer bottom of a container 51, and a temperature-sensing element (thermistor) 53 is attached to the center of the heater 52 so as to be in pressure contact with the container 51. The temperature of the water in the container 51 is indirectly detected by a temperature detection means 54 that includes the temperature-sensing element 53. When electricity is applied to the heater 52 to start heating, a temperature gradient detection means 55 detects the temperature gradient from the output of the temperature detection means 54, and stores the detected value in a first memory means 56 under predetermined conditions.

[0003] The gradient comparison means 57 compares the value stored in the first storage means 56 with the output of the temperature gradient detection means 55, and outputs a signal when the value becomes equal to or less than a predetermined ratio. Meanwhile, the temperature comparison means 58 compares the output of the temperature detection means 54 with a value stored in a non-volatile second storage means 59, and outputs a signal when the output of the temperature detection means 54 becomes equal to or greater than the stored value. The boiling detection means 60 detects boiling when either the output of the gradient comparison means 57 or the output of the temperature comparison means 58 is obtained, and stops the supply of electricity to the heater 52, and stores the output of the temperature detection means 54 at this time in the second storage means 59.

[0004] Japanese Unexamined Patent Publication No. 3-191925.

[0005] The invention described in Patent Document 1 aims to provide an electric kettle that detects boiling, and includes a ring-shaped heater 52 as heating means on the outer bottom of a container 51, with a temperature-sensing element (thermistor) 53 attached to the center of the heater so that it is pressed against the container 51. Therefore, the temperature detected is that of the outer bottom of the container 51. Since the actual temperature characteristics of the water in the container 51 vary depending on the thermal resistance, material, heat retention capacity, and capacity of the container, the actual water temperature must be detected indirectly by the temperature detection means 54. Furthermore, when the heater 52 is energized and heating begins, the temperature gradient detection means 55 detects the temperature gradient from the output of the temperature detection means 54. Therefore, it takes time to detect the actual water temperature, and rapid temperature detection is not possible.

[0006] The present invention aims to provide a method and device for estimating the temperature of contents in an electric kettle, which makes it possible to quickly and accurately estimate the temperature of water and other contents that changes from moment to moment while heating.

[0007] The device for estimating the temperature of contents in an electric kettle according to the present invention comprises a power supply stand (27) incorporating a power supply coil (13) and an electric kettle (28) incorporating a power receiving coil (14) that contactlessly receives power from the power supply coil (13), and heats contents (36) contained in a heater (18) provided in the electric kettle (28), characterized in that it comprises: a power supply circuit (19) that supplies power to the heater (18); a temperature sensor (22) that detects the temperature of the heater (18); a control unit (20) connected to the power supply circuit (19) and that controls the supply of electricity to the heater (18); a temperature memory unit (25) connected to the control unit (20) and that stores the temperature detected by the temperature sensor (22) via the control unit (20); a temperature estimation coefficient memory unit (29) that stores a preset temperature estimation coefficient (Ce) unique to the electric kettle (28); and a temperature estimation unit (26) that estimates the temperature of the contents (36) based on the data in the temperature memory unit (25) and the temperature estimation coefficient (Ce).

[0008] The temperature estimation coefficient Ce is the temperature stored in the temperature memory unit 25 when the power supply circuit 19 is controlled by a command from the control unit 20 to apply a pulse voltage to the heater 18 that is turned on between T11 and T21 and turned off between T21 and T31, and when the temperature at T21 is defined as To1, the temperature at T31 is defined as Tn1, and the temperature of the contents 36 at T31 that is actually measured by a temperature sensor different from the temperature sensor 22 is defined as Te1, the temperature estimation coefficient Ce is calculated by the following formula: Ce=(To1-Tn1) / (To1-Te1)

[0009] The estimated temperature Te of the contents 36 is the temperature stored in the temperature memory unit 25 when the power supply circuit 19 is controlled by a command from the control unit 20 to apply a pulse voltage to the heater 18 that is turned on between T1 and T2 and turned off between T2 and T3, and when the temperature at time T2 is To and the temperature at time T3 is Tn, the estimated temperature Te of the contents 36 is calculated by the temperature estimation unit 26 using the following formula: Te=To-(To-Tn) / Ce

[0010] The temperature estimation unit 26 is characterized by comprising a first subtraction circuit 30 that subtracts Tn from the output To of the temperature memory unit 25, a division circuit 31 that divides the calculation output (To-Tn) of this first subtraction circuit 30 by the temperature estimation coefficient Ce to obtain (To-Tn) / Ce, and a second subtraction circuit 32 that subtracts the output (To-Tn) / Ce of the division circuit 31 from the output To of the temperature memory unit 25 to calculate the estimated temperature Te=To-(To-Tn) / Ce of the contents 36.

[0011] The electric kettle further includes a gyro sensor 21 that is provided at approximately the center of rotation of the electric kettle 28 and outputs the rotation angle and direction of the electric kettle 28, and this gyro sensor 21 is connected to the control unit 20. The temperature set by the output of the gyro sensor 21 is stored in the temperature setting unit 24, and the control unit 20 controls the power supply of the power supply circuit 19 to make the temperature of the contents 36 coincide with the temperature set in the temperature setting unit 24.

[0012] The electric kettle further includes a gyro sensor 21, which is provided at approximately the rotation center of the electric kettle 28 and outputs the rotation angle and rotation direction of the electric kettle 28, and this gyro sensor 21 is connected to the control unit 20, and the temperature set by the output of the gyro sensor 21 is stored in the temperature setting unit 24, and the control unit 20 controls the power supply of the power supply circuit 19 so that the temperature of the contents 36 coincides with the temperature set in the temperature setting unit 24, and a vibration motor 43 is provided inside the electric kettle 28, and this vibration motor 43 is connected to the control unit 20 and set by the gyro sensor 21, and when the temperature stored in the temperature setting unit 24 reaches a predetermined value, the vibration motor 43 is driven by a signal from the control unit 20 to vibrate the electric kettle 28 to notify the user.

[0013] A method for estimating the temperature of contents in an electric kettle according to the present invention includes an apparatus including a power supply stand (27) incorporating a power supply coil (13) and an electric kettle (28) incorporating a power receiving coil (14) that contactlessly receives power from the power supply coil (13), and which heats contents (36) contained in the electric kettle (28), the apparatus including a power supply circuit (19) that supplies power to the heater (18), a temperature sensor (22) that detects the temperature of the heater (18), a control unit (20) connected to the power supply circuit (19) and controlling the energization of the heater (18), a temperature memory unit (25) connected to the control unit (20) and storing the temperature detected by the temperature sensor (22) via the control unit (20), a temperature estimation coefficient memory unit (29) that stores a preset temperature estimation coefficient (Ce) unique to the electric kettle (28), and a temperature estimation unit (26) that estimates the temperature of the contents (36) based on data in the temperature memory unit (25) and the temperature estimation coefficient (Ce), a step of controlling the power supply circuit 19 in response to a command from the control unit 20 to apply to the heater 18 a pulse voltage that is on between T11 and T21 and repeatedly off between T21 and T31; a step of determining a temperature To1 at the time of T21 and a temperature Tn1 at the time of T31 by the temperature sensor 22; a step of determining a temperature Te1 of the contents 36 at the time of T31 that is actually measured by a temperature sensor different from the temperature sensor 22; a step of determining the temperature estimation coefficient Ce specific to the electric kettle 28 by Ce=(To1-Tn1) / (To1-Te1); a step of controlling the power supply circuit 19 in response to a command from the control unit 20 to apply to the heater 18 a pulse voltage that is on between T1 and T2 and repeatedly off between T2 and T3; and a step of storing the temperature To at the time of T2 and the temperature Tn at the time of T3 measured by the temperature sensor 22 in the temperature storage unit 25. and a step of calculating the temperature Te of the contents 36 based on the preset temperature estimation coefficient Ce, the To, and the Tn by the formula Te=To-(To-Tn) / Ce.

[0014] According to the invention of claim 1, an apparatus for heating contents stored in the electric kettle includes a power supply stand with a built-in power supply coil and an electric kettle with a built-in power receiving coil that receives power contactlessly from the power supply coil, the apparatus comprising: a power supply circuit that supplies power to the heater; a temperature sensor that detects the temperature of the heater; a control unit that is connected to the power supply circuit and controls the supply of power to the heater; a temperature memory unit that is connected to the control unit and stores the temperature detected by the temperature sensor via the control unit; a temperature estimation coefficient memory unit that stores a preset temperature estimation coefficient Ce that is unique to the electric kettle; and a temperature estimation unit that estimates the temperature of the contents based on data in the temperature memory unit and the temperature estimation coefficient Ce.Therefore, by setting and registering the temperature estimation coefficient Ce that is unique to the electric kettle in advance, the temperature of the contents can be accurately and quickly estimated from the measurement value of the temperature sensor that measures the temperature of the heater, without using a temperature sensor that directly measures the temperature of the contents.

[0015] According to the invention of claim 2, the temperature estimation coefficient Ce is the temperature stored in the temperature memory unit when the power supply circuit is controlled by a command from the control unit to apply to the heater a pulse voltage that is on between T11 and T21 and off between T21 and T31 repeatedly, and when the temperature at T21 is To1, the temperature at T31 is Tn1, and the temperature of the contents at T31 measured by a temperature sensor different from the temperature sensor is Te1, the temperature estimation coefficient Ce is found by calculating Ce=(To1-Tn1) / (To1-Te1), and therefore the temperature estimation coefficient Ce specific to the electric kettle can be easily found.

[0016] According to the invention of claim 3, the temperature stored in the temperature memory unit when a pulse voltage is applied to the heater by controlling the power supply circuit in response to a command from the control unit, which is turned on between T1 and T2 and turned off between T2 and T3, and in which the temperature at T2 is To and the temperature at T3 is Tn, the estimated temperature Te of the contents can be easily and accurately calculated by the temperature estimation unit using the formula Te = To - (To - Tn) / Ce.

[0017] According to the invention of claim 4, the temperature estimation unit comprises a first subtraction circuit that subtracts Tn from the output To of the temperature memory unit, a division circuit that divides the calculation output (To-Tn) of this first subtraction circuit by the temperature estimation coefficient Ce to obtain (To-Tn) / Ce, and a second subtraction circuit that subtracts the output (To-Tn) / Ce of the division circuit from the output To of the temperature memory unit to calculate the estimated temperature Te=To-(To-Tn) / Ce of the contents, so the temperature estimation unit can be constructed from a simple subtraction circuit and division circuit.

[0018] According to the invention of claim 5, the electric kettle further comprises a gyro sensor provided at approximately the center of rotation of the electric kettle and outputting the rotation angle and direction of the electric kettle, this gyro sensor is connected to the control unit, the temperature set by the output of the gyro sensor is stored in the temperature setting unit, and the control unit controls the power supply of the power supply circuit so that the temperature of the contents coincides with the temperature set in the temperature setting unit, so that the set temperature can be set by the rotation angle and direction of the electric kettle.

[0019] According to the invention of claim 6, the electric kettle further comprises a gyro sensor provided at approximately the center of rotation of the electric kettle and outputting the rotation angle and direction of the electric kettle, this gyro sensor is connected to the control unit, the temperature set by the output of the gyro sensor is stored in the temperature setting unit, the control unit controls the power supply of the power supply circuit to make the temperature of the contents match the temperature set in the temperature setting unit, a vibration motor is provided inside the electric kettle and connected to the control unit, and when the temperature set by the gyro sensor reaches a predetermined value, the vibration motor is driven by a signal from the control unit to vibrate the electric kettle to notify the user, so that the set temperature can be felt by touch.

[0020] According to the invention of claim 7, an apparatus for heating contents stored in the electric kettle includes a power supply stand having a built-in power supply coil and an electric kettle having a built-in power receiving coil that receives power contactlessly from the power supply coil, the apparatus comprising: a power supply circuit that supplies power to the heater; a temperature sensor that detects the temperature of the heater; a control unit that is connected to the power supply circuit and controls the supply of power to the heater; a temperature memory unit that is connected to the control unit and stores the temperature detected by the temperature sensor via the control unit; a temperature estimation coefficient memory unit that stores a temperature estimation coefficient Ce that is preset unique to the electric kettle; and a temperature estimation unit that estimates the temperature of the contents based on data in the temperature memory unit and the temperature estimation coefficient Ce, the apparatus comprising: a step of controlling the power supply circuit in response to a command from the control unit to apply to the heater a pulse voltage that is turned on between T11 and T21 and turned off between T21 and T31 repeatedly; and a step of using the temperature sensor to determine a temperature To1 at T21 and a temperature Tn1 at T31. the temperature To at T2 and the temperature Tn at T3 measured by the temperature sensor; and the temperature Te of the contents at T31 measured by a temperature sensor different from the temperature sensor. The temperature estimation coefficient Ce specific to the electric kettle is calculated by Ce = (To1 - Tn1) / (To1 - Te1). The control unit commands the power supply circuit to apply a pulse voltage to the heater that is on between T1 and T2 and off between T2 and T3. The temperature To at T2 and the temperature Tn measured by the temperature sensor are stored in the temperature storage unit. The temperature Te of the contents is calculated by Te = To - (To - Tn) / Ce based on the preset temperature estimation coefficient Ce, the To, and the Tn. Therefore, the temperature of the contents can be estimated according to the characteristics specific to the electric kettle.

[0021] Fig. 1 is a cross-sectional view showing a first embodiment of a method and device for estimating the temperature of contents in an electric kettle according to the present invention. Fig. 2 is an electrical circuit diagram showing a first embodiment of a method and device for estimating the temperature of contents in an electric kettle according to the present invention. Fig. 3 is a block diagram of the temperature estimation unit 26 in Fig. 2. Fig. 4 is a flowchart of a method and device for estimating the temperature of contents in an electric kettle according to the present invention. Fig. 5 is a flowchart of a method and device for estimating the temperature of contents in an electric kettle according to the present invention when estimating the liquid temperature. Fig. 6 is an operational waveform diagram of a method and device for estimating the temperature of contents in an electric kettle according to the present invention. Fig. 7 is an explanatory diagram of a conventional electric kettle.

[0022] The device for estimating the temperature of contents in an electric kettle according to the present invention comprises a power supply stand (27) incorporating a power supply coil (13) and an electric kettle (28) incorporating a power receiving coil (14) that contactlessly receives power from the power supply coil (13), and heats contents (36) contained in a heater (18) provided in the electric kettle (28), and comprises: a power supply circuit (19) that supplies power to the heater (18); a temperature sensor (22) that detects the temperature of the heater (18); a control unit (20) connected to the power supply circuit (19) and that controls the supply of electricity to the heater (18); a temperature memory unit (25) connected to the control unit (20) and that stores the temperature detected by the temperature sensor (22) via the control unit (20); a temperature estimation coefficient memory unit (29) that stores a preset temperature estimation coefficient (Ce) unique to the electric kettle (28); and a temperature estimation unit (26) that estimates the temperature of the contents (36) based on the data in the temperature memory unit (25) and the temperature estimation coefficient (Ce).

[0023] The temperature estimation coefficient Ce is the temperature stored in the temperature memory unit 25 when the power supply circuit 19 is controlled by a command from the control unit 20 to apply a pulse voltage to the heater 18 that is turned on between T11 and T21 and turned off between T21 and T31 repeatedly, and when the temperature at T21 is defined as To1, the temperature at T31 is defined as Tn1, and the temperature of the contents 36 at T31 that is actually measured by a temperature sensor different from the temperature sensor 22 is defined as Te1, the temperature estimation coefficient Ce is calculated by the following formula: Ce=(To1-Tn1) / (To1-Te1).

[0024] The temperature stored in the temperature memory unit 25 when a pulse voltage is applied to the heater 18 by controlling the power supply circuit 19 in response to a command from the control unit 20, which is turned on between T1 and T2 and turned off between T2 and T3, and the temperature at time T2 is To and the temperature at time T3 is Tn, the estimated temperature Te of the contents 36 is calculated by the temperature estimation unit 26 using the following formula: Te=To-(To-Tn) / Ce

[0025] The temperature estimation unit 26 comprises a first subtraction circuit 30 that subtracts Tn from the output To of the temperature memory unit 25, a division circuit 31 that divides the calculation output (To-Tn) of this first subtraction circuit 30 by the temperature estimation coefficient Ce to obtain (To-Tn) / Ce, and a second subtraction circuit 32 that subtracts the output (To-Tn) / Ce of the division circuit 31 from the output To of the temperature memory unit 25 to calculate the estimated temperature Te=To-(To-Tn) / Ce of the contents 36.

[0026] The electric kettle 28 further includes a gyro sensor 21 that is provided at approximately the center of rotation of the electric kettle 28 and outputs the rotation angle and direction of the electric kettle 28. The gyro sensor 21 is connected to the control unit 20, and the temperature set by the output of the gyro sensor 21 is stored in the temperature setting unit 24. The control unit 20 controls the power supply of the power supply circuit 19 to make the temperature of the contents 36 coincide with the temperature set in the temperature setting unit 24.

[0027] The electric kettle 28 further includes a gyro sensor 21, which is provided at approximately the rotation center of the electric kettle 28 and outputs the rotation angle and rotation direction of the electric kettle 28, and this gyro sensor 21 is connected to the control unit 20, and the temperature set by the output of the gyro sensor 21 is stored in the temperature setting unit 24, and the control unit 20 controls the power supply of the power supply circuit 19 so that the temperature of the contents 36 coincides with the temperature set in the temperature setting unit 24, and a vibration motor 43 is provided inside the electric kettle 28, and this vibration motor 43 is connected to the control unit 20 and set by the gyro sensor 21, and when the set temperature stored in the temperature setting unit 24 reaches a predetermined value, the vibration motor 43 is driven by a signal from the control unit 20 to vibrate the electric kettle 28 to alert the user.

[0028] a power supply circuit that supplies power to the heater; a temperature sensor that detects the temperature of the heater; a control unit that is connected to the power supply circuit and controls the power supply to the heater; a temperature memory that is connected to the control unit and stores the temperature detected by the temperature sensor via the control unit; a temperature estimation coefficient memory that stores a preset temperature estimation coefficient that is unique to the electric kettle; and a temperature estimation unit that estimates the temperature of the contents based on data in the temperature memory and the temperature estimation coefficient. a step of controlling the power supply circuit 19 in response to a command from the control unit 20 to apply to the heater 18 a pulse voltage that is on between T11 and T21 and repeatedly off between T21 and T31; a step of determining a temperature To1 at the time of T21 and a temperature Tn1 at the time of T31 by the temperature sensor 22; a step of determining a temperature Te1 of the contents 36 at the time of T31 that is actually measured by a temperature sensor different from the temperature sensor 22; a step of determining the temperature estimation coefficient Ce specific to the electric kettle 28 by Ce=(To1-Tn1) / (To1-Te1); a step of controlling the power supply circuit 19 in response to a command from the control unit 20 to apply to the heater 18 a pulse voltage that is on between T1 and T2 and repeatedly off between T2 and T3; and a step of storing the temperature To at the time of T2 and the temperature Tn at the time of T3 measured by the temperature sensor 22 in the temperature storage unit 25. and a step of calculating the temperature Te of the contents 36 based on the preset temperature estimation coefficient Ce, the To and the Tn by the formula Te=To-(To-Tn) / Ce.

[0029] A first embodiment of the present invention will be described below with reference to FIGS. 1 to 6. In FIG. 1, a method and apparatus for estimating the temperature of contents in an electric kettle according to the present invention includes a power supply stand 27 and an electric kettle 28 placed on the power supply stand 27. A power supply coil 13 in the power supply stand 27 and a power receiving coil 14 in the electric kettle 28 are magnetically coupled, and power is transmitted by electromagnetic induction and magnetic field resonance with a resonant capacitor. The power supply stand 27 is thin, approximately 10 to 15 mm thick, and has a diameter of approximately 100 to 200 mm. Inside the power supply stand 27, as shown in FIG. 2, an AC adapter 10a connected to an AC power source 10, a rectifier circuit 11, an inverter circuit 12 for converting the power to a high-frequency signal, and the power supply coil 13 are built in. The AC adapter 10a connected to the AC power source 10 and the rectifier circuit 11 may be provided external to the power supply stand 27. The electric kettle 28 contains water or other contents 36 to be heated, and the electric kettle body 37 is airtightly fitted into a lower exterior material 40 with a gasket 41 interposed between them. The electric kettle body 37 is composed of a double wall, an inner wall 38a and an outer wall 38b, and the interior forms a vacuum insulation section 39. The electric kettle body 37 is covered with a lid 42. A board holder 45 is provided between the bottom 44 of the exterior material 40 and the bottom of the electric kettle body 37. A wiring board 47 is disposed between the board holder 45 and a board holder cover 46 below the board holder 45, and the power receiving coil 14 is attached between the underside of the board holder cover 46 and the bottom 44.

[0030] A vibration motor 43 is provided on the side of the board holder 45. A ceramic heater 18, supported by an inner bottom cover 50, is attached to the outer surface of the bottom of the electric kettle body 37. A temperature sensor 22 is attached to the underside of the heater 18, and the heater 18 is pressed against the bottom of the electric kettle body 37 by a spring plate 48 between the board holder 45 and the inner bottom cover 50. The heater 18 is configured by a thin, serpentine heater pattern formed on a ceramic thin plate, with a thin thermistor located in the center of the heater pattern. The wiring board 47 is provided with circuit elements including a microcomputer-based control unit 20 and other circuits, as shown in FIG. 2. More specifically, the wiring board 47 includes a resonance capacitor 15 connected to the power receiving coil 14 and conducting power by magnetic field resonance, a rectifier circuit 16 that rectifies the high-frequency power received by the power receiving coil 14, a smoothing capacitor 17, and a power supply circuit 19 consisting of a switch circuit such as a MOS-FET. Also connected to the control unit 20 are a temperature memory unit 25 that stores the temperature detected by the temperature sensor 22, a temperature estimation unit 26 that estimates the temperature of the contents 36, a non-volatile memory 23 that stores the current set temperature of the electric kettle 28, a gyro sensor 21 that detects the angular velocity of the electric kettle 28 provided approximately in the center of the wiring board 47 and sets the temperature of the contents 36, a temperature setting unit 24 that stores the set temperature of the contents 36, and a wireless communication unit 9, and is further connected to the vibration motor 43. A temperature estimation coefficient memory unit 29 is connected to the temperature estimation unit 26 and stores a temperature estimation coefficient Ce that is preset based on the thermal resistance, material, heat retention capacity, and volume of a container constituting the electric kettle 28.

[0031] The temperature estimation unit 26 comprises a first subtraction circuit 30 that subtracts Tn (the temperature obtained in step a8 described later) input to a second temperature signal input terminal 34 from To (the temperature obtained in step a5 described later) output from the temperature memory unit 25 and input to a first temperature signal input terminal 33, a division circuit 31 that divides the calculation output To-Tn of the first subtraction circuit 30 by the preset temperature estimation coefficient Ce to obtain (To-Tn) / Ce, and a second subtraction circuit 32 that subtracts the output (To-Tn) / Ce of the division circuit 31 from To output from the temperature memory unit 25 and input to the first temperature signal input terminal 33 to calculate the estimated temperature Te=To-(To-Tn) / Ce of the contents 36. In FIG. 6, To and Tn are temperatures detected by applying a pulse voltage to the heater 18 that is turned on between T1 and T2 and turned off between T2 and T3 repeatedly to obtain the estimated temperature Te of the contents 36, where To is the temperature obtained in step a5 described later, and Tn is the temperature obtained in step a8 described later.

[0032] The heating process for the contents 36 in this configuration will be described with reference to FIG. 4. a1: When the electric kettle 28 is placed at the center of the power supply stand 27, the temperature setting unit 24 is initialized to the set temperature immediately before the electric kettle 28 was removed from the power supply stand 27, based on the data stored in the non-volatile memory 23 via the control unit 20. For example, assume that the set temperature is initialized to 55°C. At this time, the contents 36 and the heater 18 are considered to be in thermal equilibrium, and the temperature of the heater 18 is measured by the temperature sensor 22, and this temperature is set as the current temperature of the contents 36. For example, assume that the current temperature is 50°C. a2: At this time, if the set temperature - the current temperature of the contents 36 > a°C (for example, a = 0.5°C), the result is YES. a3: The control unit 20 closes the power supply circuit 19 to supply power to the heater 18 to heat the contents. a4: Wait for t1 seconds (for example, t1 = 15 seconds). a5: The temperature of the heater 18 is detected by the temperature sensor 22, and this temperature is set as To and stored in the temperature storage unit 25 via the control unit 20. a6: The power supply circuit 19 is opened to stop heating by the heater 18.

[0033] a7: Wait t2 seconds (for example, t2 = 5 seconds). a8: The temperature of the heater 18 is detected by the temperature sensor 22, and this temperature is stored as Tn in the temperature memory unit 25 via the control unit 20. a9: The temperature estimation unit 26 calculates the estimated temperature Te. Details will be described later. a10: The estimated temperature Te is set as the current temperature of the contents 36. a11: If the result of "Set temperature - Current temperature of the contents 36 > a°C" is YES, return to the initial step a3. a12: If the result of "Set temperature - Current temperature of the contents 36 > a°C" is NO in step a11, wait t3 seconds (for example, t3 = 40 seconds). This step is a step of waiting for the heater 18 and the contents 36 to reach temperature equilibrium. a13: The temperature of the heater 18 is detected by the temperature sensor 22, and this temperature is set as the current temperature of the contents 36, and return to step a2. a14: In step a2, if the result of "Set temperature - Current temperature of contents 36 > a°C" is NO, wait for t4 seconds (for example, t4 = 1 second). a15: The temperature of heater 18 is detected by temperature sensor 22, and this temperature is set as the current temperature of contents 36, and the process returns to step a2.

[0034] The details of the step a9 in which the temperature estimator 26 calculates the estimated temperature Te are described with reference to FIGS. 5 and 6. This step estimates the temperature of the contents 36 heated by the electric kettle 28 using the value detected by the temperature sensor 22 mounted on the outer bottom surface of the electric kettle body 37 and the temperature estimation coefficient Ce specific to the electric kettle 28, without using a temperature sensor directly connected to the contents 36. For this step, the temperature estimation coefficient Ce specific to the electric kettle 28 is determined in advance during the development of the electric kettle 28 shown in FIG. 1. The correlation between the heating of the contents 36 by the heater 18 and the temperature of the contents 36 varies depending on the power supplied to the heater 18, the thermal resistance between the heater 18 and the electric kettle 28, the material of the electric kettle 28, the heat retention capacity of the electric kettle 28, the capacity of the electric kettle 28, etc. Therefore, the temperature estimation coefficient Ce specific to the electric kettle 28 is preset in the next step. In FIG. 6 , at time T11, the power supply circuit 19 is closed, and the heater 18 is energized and heated from T11 to T21 (e.g., 15 seconds). The temperature To1 of the heater 18 at this time is detected and stored by the temperature sensor 22. Next, the heater 18 is deenergized from T21 to T31 (e.g., 5 seconds), and the temperature Tn1 of the heater 18 at this time is detected and stored by the temperature sensor 22. At the same time, the actual temperature of the contents 36 at time T31 is measured by another temperature sensor (not shown), and the temperature Te1 at this time is stored. Based on these values ​​To1, Tn1, and Te1, a value satisfying the following equation is determined in advance during the development of the electric kettle 28 as the temperature estimation coefficient Ce of the electric kettle 28: Ce = (To1 - Tn1) / (To1 - Te1). Incidentally, a specific example of the temperature estimation coefficient Ce obtained was 0.57.

[0035] The steps will be explained in detail with reference to FIG. 5. a91: At time T1 in FIG. 6, the power supply circuit 19 is closed. Step a3 corresponds to this step. a92: The heater 18 is heated for a predetermined time (t8 seconds) (time T1-T2, for example, 15 seconds). Step a4 corresponds to this step. a93: The temperature To of the heater 18 at time T2 is detected by the temperature sensor 22, and this To is stored in the temperature memory unit 25 via the control unit 20. Step a5 corresponds to this step. a94: At time T2, the power supply circuit 19 is opened to stop heating by the heater 18. Step a6 corresponds to this step. a95: Heating is stopped for a predetermined time (t9 seconds) (time T2-T3, for example, 5 seconds). Step a7 corresponds to this step. a96: The temperature Tn of the heater 18 at time T3 is detected by the temperature sensor 22, and this Tn is stored in the temperature memory unit 25 via the control unit 20. Step a8 corresponds to this step. a97: The temperature estimator 26 calculates an estimated temperature Te using To and Tn input from the temperature memory unit 25 to the temperature estimator 26 and Ce input from the temperature estimation coefficient memory unit 29. Step a9 corresponds to this step. As shown in FIG. 3 , the temperature estimator 26 calculates Te by subtracting Tn input from the temperature memory unit 25 to the second temperature signal input terminal 34 from To input from the temperature memory unit 25 to the first temperature signal input terminal 33 in a first subtraction circuit 30 to obtain (To - Tn). A division circuit 31 divides (To - Tn) obtained by the first subtraction circuit 30 by Ce stored in advance in the temperature estimation coefficient memory unit 29 to obtain (To - Tn) / Ce. A second subtraction circuit 32 subtracts (To - Tn) / Ce obtained by the division circuit 31 from To input to the first temperature signal input terminal 33. As a result, Te is obtained at output terminal 35 by the following formula: Te=To-(To-Tn) / Ce The temperature of contents 36 obtained in this manner is used for temperature control as the current temperature, and is also transmitted from wireless communication unit 9 to wireless terminal 8 via control unit 20 and displayed on display unit 7 provided on wireless terminal 8.

[0036] When the electric kettle 28 is placed at the center of the power supply stand 27, the temperature setting unit 24 is initialized to the temperature set immediately before the electric kettle 28 was removed from the power supply stand 27, based on the data stored in the nonvolatile memory 23 via the control unit 20. To increase the temperature set in the temperature setting unit 24, the user places their hand on the electric kettle 28 and rotates it clockwise by a predetermined angle. The gyro sensor 21 then detects the angular velocity of the electric kettle 28 and outputs the result to the control unit 20. The control unit 20 then increases the temperature set in the temperature setting unit 24 by 1°C per 20 degrees of central angle, for example, and stores the temperature set in the temperature setting unit 24 in the nonvolatile memory 23. By repeating the heating process using the temperature set in the temperature setting unit 24, the temperature of the contents 36 rises to the desired temperature. To decrease the temperature set in the temperature setting unit 24, the user places their hand on the electric kettle 28 and rotates it counterclockwise by a predetermined angle. Then, gyro sensor 21 detects the angular velocity of electric kettle 28 and outputs the result to control unit 20, and control unit 20 decreases the set temperature of temperature setting unit 24 by 1°C per 20 degrees of central angle, for example, and stores the set temperature of temperature setting unit 24 in non-volatile memory 23. By repeating the heating process using the set temperature of temperature setting unit 24, the temperature of content 36 decreases to the target temperature.

[0037] In FIG. 1, a vibration motor 43 is built into a circuit board holder 45 inside the electric kettle 28, and the electric kettle 28 can vibrate in the following cases to notify the user.

[0038] 7...Display unit, 8...Wireless terminal, 9...Wireless communication unit, 10...AC power supply, 11...Rectifier circuit, 12...Inverter circuit, 13...Power supply coil, 14...Power receiving coil, 15...Resonant capacitor, 16...Rectifier circuit, 17...Smoothing capacitor, 18...Heater, 19...Power supply circuit, 20...Control unit, 21...Gyro sensor, 22...Temperature sensor, 23...Non-volatile memory, 24...Temperature setting unit, 25...Temperature storage unit, 26...Temperature estimation unit, 27...Power supply stand, 28...Electric kettle, 29...Temperature estimation coefficient storage unit, 30...First subtraction circuit, 31...Division circuit, 32...Second subtraction circuit, 33...First temperature signal input terminal terminal, 34...second temperature signal input terminal, 35...output terminal, 36...contents, 37...electric kettle body, 38a...inner wall portion, 38b...outer wall portion, 39...vacuum insulation portion, 40...exterior material, 41...packing, 42...lid, 43...vibration motor, 44...bottom, 45...board holder, 46...board holder cover, 47...wiring board, 48...spring plate, 49...mica plate, 50...inner bottom cover, 51...container, 52...heater, 53...thermosensitive element, 54...temperature detection means, 55...temperature gradient detection means, 56...first memory means, 57...gradient comparison means, 58...temperature comparison means, 59...second memory means, 60...boiling detection means.

Claims

1. An apparatus for heating contents contained in an electric kettle having a power supply base with a built-in power supply coil and an electric kettle with a built-in power receiving coil that receives power wirelessly from the power supply coil, the apparatus comprising: a power supply circuit that supplies power to the heater; a temperature sensor that detects the temperature of the heater; a control unit coupled to the power supply circuit that controls energization of the heater; a temperature storage unit coupled to the control unit that stores the detected temperature of the temperature sensor via the control unit; a temperature estimation coefficient storage unit that stores a preset specific temperature estimation coefficient Ce of the electric kettle; and a temperature estimation unit that estimates the temperature of the contents based on the data of the temperature storage unit and the temperature estimation coefficient Ce. The apparatus for estimating the temperature of the contents in the electric kettle is characterized by comprising the above components.

2. The temperature estimation coefficient Ce is the temperature stored in the temperature storage unit when a pulse voltage that turns on between T11 and T21 and turns off between T21 and T31 is applied to the heater by controlling the power supply circuit according to a command from the control unit. When the temperature at T21 is To1, the temperature at T31 is Tn1, and the temperature measured by a temperature sensor different from the temperature sensor of the contents at T31 is Te1, the temperature estimation coefficient Ce is obtained by calculating the following formula. The apparatus for estimating the temperature of the contents in the electric kettle according to claim 1 is characterized by this. Ce = (To1 - Tn1) / (To1 - Te1) 3. When the temperature stored in the temperature storage unit when a pulse voltage that turns on between T1 and T2 and turns off between T2 and T3 is applied to the heater by controlling the power supply circuit according to a command from the control unit, and the temperature at T2 is To and the temperature at T3 is Tn, the estimated temperature Te of the contents is obtained by calculating the following formula in the temperature estimation unit. The apparatus for estimating the temperature of the contents in the electric kettle according to claim 2 is characterized by this. Te = To - (To - Tn) / Ce 4. The temperature estimation unit includes a first subtraction circuit that subtracts Tn from the output To of the temperature storage unit, a division circuit that divides the arithmetic output (To - Tn) of the first subtraction circuit by the temperature estimation coefficient Ce to obtain (To - Tn) / Ce, and a second subtraction circuit that subtracts the output (To - Tn) / Ce of the division circuit from the output To of the temperature storage unit to calculate the estimated temperature Te of the content = To - (To - Tn) / Ce. The apparatus for estimating the temperature of the content in the electric kettle according to claim 3, characterized in that it comprises the above.

5. The apparatus for estimating the temperature of the content in the electric kettle according to claim 1, further comprising a gyro sensor provided at a substantially rotation center position of the electric kettle, which outputs a rotation angle and a rotation direction of the electric kettle, coupling the gyro sensor to the control unit, storing the temperature set by the output of the gyro sensor in the temperature setting unit, and controlling the power supply of the power supply circuit by the control unit so that the temperature of the content coincides with the set temperature of the temperature setting unit.

6. The apparatus for estimating the temperature of the content in the electric kettle according to claim 1, further comprising a gyro sensor provided at a substantially rotation center position of the electric kettle, which outputs a rotation angle and a rotation direction of the electric kettle, coupling the gyro sensor to the control unit, storing the temperature set by the output of the gyro sensor in the temperature setting unit, controlling the power supply of the power supply circuit by the control unit so that the temperature of the content coincides with the set temperature of the temperature setting unit, providing a vibration motor inside the electric kettle, coupling the vibration motor to the control unit, and driving the vibration motor by a signal of the control unit to vibrate the electric kettle for notification when the set temperature by the gyro sensor reaches a predetermined value.

7. An apparatus comprising a power supply base incorporating a power supply coil and an electric kettle incorporating a power receiving coil for non-contact power reception from the power supply coil, the apparatus heating the contents contained by a heater provided in the electric kettle, the apparatus comprising: a power supply circuit for supplying power to the heater; a temperature sensor for detecting the temperature of the heater; a control unit coupled to the power supply circuit for controlling energization of the heater; a temperature storage unit coupled to the control unit for storing the detected temperature of the temperature sensor via the control unit; a temperature estimation coefficient storage unit for storing a unique temperature estimation coefficient Ce preset for the electric kettle; and a temperature estimation unit for estimating the temperature of the contents based on the data of the temperature storage unit and the temperature estimation coefficient Ce. A method for estimating the temperature of the contents in an electric kettle, comprising: a step of controlling the power supply circuit according to a command of the control unit to apply a pulse voltage to the heater, which is turned on between T11 and T21 and turned off between T21 and T31; a step of obtaining, by the temperature sensor, the temperature To1 at T21 and the temperature Tn1 at T31; a step of obtaining the temperature Te1 measured by a temperature sensor different from the temperature sensor of the contents at T31; a step of obtaining the unique temperature estimation coefficient Ce of the electric kettle by Ce = (To1 - Tn1) / (To1 - Te1); a step of controlling the power supply circuit according to a command of the control unit to apply a pulse voltage to the heater, which is turned on between T1 and T2 and turned off between T2 and T3; a step of storing, in the temperature storage unit, the temperature To at T2 and the temperature Tn at T3 measured by the temperature sensor; and a step of obtaining the temperature Te of the contents by an operation of Te = To - (To - Tn) / Ce based on the preset temperature estimation coefficient Ce, the temperature To, and the temperature Tn.

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