CN113849010A

CN113849010A - Temperature control method and heating equipment

Info

Publication number: CN113849010A
Application number: CN202111022685.6A
Authority: CN
Inventors: 朱泽春; 徐小亮; 谷晓峰
Original assignee: Joyoung Co Ltd
Current assignee: Joyoung Co Ltd
Priority date: 2021-09-01
Filing date: 2021-09-01
Publication date: 2021-12-28

Abstract

The application discloses temperature control method and heating equipment, it is applicable to heating equipment, includes: acquiring an input voltage of the heating equipment; acquiring the temperature difference between the current temperature and the target temperature; carrying out proportional/integral control on the heating power based on the temperature difference to obtain initial heating power; adjusting the initial heating power according to the input voltage to obtain actual heating power; and heating by utilizing the actual heating power. The heating power of the heating equipment is adjusted according to the standard voltage, then the heating power is adjusted again based on the actual input voltage, the deviation of the adjustment amount caused by voltage fluctuation is reduced, the adjustment accuracy of the heating equipment on the heating power is improved, the actual heating power is more accurate, and the temperature control is more reliable.

Description

Temperature control method and heating equipment

Technical Field

The invention relates to the field of temperature control, in particular to a temperature control method and heating equipment.

Background

With the technological progress and the improvement of the living standard of people, various heating devices such as a water heater, a water dispenser, an electric cooker, an air fryer, an oven and the like appear in the market. However, under the influence of the voltage fluctuation of the utility power, in an area with large voltage fluctuation, the actual input voltage and the actual heating power of the heating device cannot be known, so that the heating device cannot adjust the heating power accurately, the actual heating power is inaccurate, and the temperature control of the heating device is unreliable.

Therefore, how to improve the accuracy of the heating power adjustment of the heating device, so that the actual heating power is more accurate, and a solution is urgently needed.

Disclosure of Invention

In order to solve the technical problems described in the background art, a first objective of the present application is to provide a temperature control method, which adjusts the heating power of a heating device according to a standard voltage, and then adjusts the heating power again based on an actual input voltage, so as to reduce an adjustment deviation caused by voltage fluctuation, improve the adjustment accuracy of the heating device on the heating power, make the actual heating power more accurate, and make the temperature control more reliable.

A second objective of the present application is to provide a heating apparatus, which controls the heating temperature based on the above temperature control method, and improves the accuracy of adjusting the heating power, so that the actual heating power is more accurate, and the temperature control is more reliable.

In order to achieve the first object, the present application adopts the following technical solutions:

a temperature control method, which is applied to a heating apparatus, comprising: acquiring an input voltage of the heating equipment; acquiring the temperature difference between the current temperature and the target temperature; carrying out proportional/integral control on the heating power based on the temperature difference to obtain initial heating power; adjusting the initial heating power according to the input voltage to obtain actual heating power; and heating by utilizing the actual heating power. It should be understood by those skilled in the art that the heating power for proportional/integral control should be the heating power at the standard voltage, and as an exemplary embodiment, based on the current temperature difference, the heating apparatus performs proportional/integral control on the current heating power as the heating power at the standard voltage to obtain the initial heating power, and is influenced by the voltage fluctuation, the current input voltage may not be the standard voltage, and the current heating power may not be the heating power at the standard voltage under the condition that other conditions are the same for the same heated object (for example, the same volume of water, air, and the same amount of the same food material), and therefore, the initial heating power may have a deviation, may be larger or smaller, compared to the current actually required heating power. Therefore, the initial heating power is adjusted for the second time based on the input voltage, so that the actual heating power is closer to the heating power really required under the current temperature difference, the deviation of the regulating quantity caused by voltage fluctuation is reduced, the adjusting accuracy of the heating equipment on the heating power is improved, the actual heating power is more accurate, and the temperature control is more reliable.

Optionally, the adjusting the initial heating power according to the input voltage includes: acquiring a preset power amplitude limit value corresponding to the target temperature; limiting the initial heating power below the preset power limit value based on the input voltage. The protection circuit can protect elements in the circuit and prevent potential safety hazards caused by too fast temperature rise.

Optionally, the adjusting the initial heating power according to the input voltage includes: comparing the input voltage with a preset input voltage; when the input voltage is greater than the preset input voltage, reducing the initial heating power; and when the input voltage is smaller than the preset input voltage, increasing the initial heating power, wherein the adjustment amplitude of the initial heating power is positively correlated with the absolute value of the voltage difference between the input voltage and the preset input voltage. The initial heating power after adjustment, namely the actual heating power can be the same as the really required heating power, so that the heating equipment is heated by the actual heating power, the influence caused by voltage fluctuation is reduced, the adjustment accuracy of the heating equipment on the heating power is improved, the actual heating power is more accurate, and the temperature control is more reliable.

Optionally, the obtaining the input voltage includes: heating the heated material in the heating device with preset heating power; acquiring temperature change information of the heated object for representing the heating rate in the heating process; determining the input voltage based on the temperature change information. The input voltage of the heating device can be safely and reliably acquired.

Optionally, the proportionally/integratedly controlling the heating power based on the temperature difference comprises: acquiring the sampling delay time of a temperature sensor; and determining a control period of proportional/integral control based on the delay time length, wherein the control period is greater than the delay time length, and the difference between the control period and the delay time length is less than a preset value. The control response speed can be ensured to be high, and meanwhile, temperature control overshoot is prevented.

Optionally, the proportionally/integratedly controlling the heating power based on the temperature difference comprises: acquiring real-time temperature response time of a temperature sensor; and controlling a proportional parameter in the proportional/integral control to adjust along with the real-time temperature response time, wherein the proportional parameter is inversely related to the real-time temperature response time. Therefore, the proportion parameters can be dynamically adjusted along with the real-time temperature response time, the control precision of the heating power is improved, and the precision of temperature control is further improved.

Optionally, the proportionally/integratedly controlling the heating power based on the temperature difference comprises: judging whether the temperature difference is larger than a preset temperature difference or not; when the temperature difference is larger than a preset temperature difference, the heating power is adjusted by adopting proportional control; and when the temperature difference is smaller than the preset temperature difference, adjusting the heating power by adopting integral control. Therefore, when the temperature difference is large, the heating power is adjusted by adopting proportional control, the adjusting amplitude is large, the adjustment can be accelerated, the time for the current temperature to reach the target temperature is reduced, the heating time is reduced, the temperature difference can not be eliminated by proportional control, and the temperature difference exists all the time, so that when the temperature difference is small, the integral control is used for adjusting the heating power, the integral control is carried out as long as the temperature difference exists, and the integral control is carried out until the current temperature reaches the target temperature and the temperature difference does not exist, so that the adjustment can be accelerated, the heating time is shortened, and the temperature difference can be reduced to no difference.

Optionally, the temperature control method further comprises: acquiring a heating boiling instruction; judging whether the current temperature reaches a preset temperature or not, wherein the preset temperature is less than a boiling temperature; when the current temperature reaches the preset temperature, switching to power-limiting heating, and adjusting the current heating power of the heating equipment to be within a preset heating power range based on the input voltage, wherein the preset temperature is positively correlated with the quantity of the heated objects.

Optionally, the temperature control method further comprises: and continuously heating with the heating power within the preset heating power range and collecting the boiling point.

In order to achieve the second object, the present application adopts the following technical solutions:

a heating apparatus comprising a processor, a memory and executable instructions stored on the memory, the executable instructions being arranged to, when executed by the processor, cause the heating apparatus to perform the temperature control method described above.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic flow chart of a temperature control method according to an embodiment of the present disclosure;

FIG. 2 is a schematic flow chart illustrating a process of obtaining an input voltage of a heating device in a temperature control method according to an embodiment of the present disclosure;

FIG. 3 is a graph illustrating a relationship between a temperature value and a digital value AD of a NTC temperature sensor according to an embodiment of the present application;

FIG. 4 is a schematic diagram of a heating apparatus according to an embodiment of the present application;

fig. 5 is a schematic diagram of a control circuit of a heating apparatus according to an embodiment of the present application.

R1. a heating body; s1, a first switch; s2, a second switch; and S3, controlling a switching tube.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals indicate the same or structurally similar but functionally identical elements.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

In order to solve the technical problem of how to improve the accuracy of adjusting the heating power by the heating device, so that the actual heating power is more accurate, an embodiment of the present application provides a temperature control method, and fig. 1 is a schematic flow diagram of the temperature control method in an embodiment of the present application; FIG. 2 is a schematic flow chart illustrating a process of obtaining an input voltage of a heating device in a temperature control method according to an embodiment of the present disclosure; fig. 3 is a graph of a temperature value and a temperature digital value AD of an NTC temperature sensor according to an embodiment of the present disclosure.

Referring to fig. 1, a temperature control method may include the steps of:

s10, acquiring input voltage of the heating equipment. In this embodiment, the input voltage refers to the actual input voltage of the heating device, and the input voltage may be obtained by measurement by the existing measurement and calculation method, and may be collected in real time or collected at intervals. As an exemplary embodiment, the heating device may include a water heater, a water dispenser, a rice cooker, an air fryer, an oven, etc., and the heated object may include water, food, air, etc.

S20, acquiring the temperature difference between the current temperature and the target temperature. As an exemplary embodiment, the current temperature may be measured by a temperature sensor, and particularly, in the case of a water heater, the heating apparatus may include a water storage device, and the temperature sensor may be disposed inside the water storage device to detect the water temperature in real time. As an exemplary embodiment, the target temperature may be set by a user through active operation, and the user may set the target temperature through a key, touch or remote control manner, specifically, the target temperature may be a plurality of preselected temperatures possessed by the heating device, such as 45 ℃, 50 ℃, 80 ℃, 90 ℃, 95 ℃, or any temperature set by the user.

S30, carrying out proportional/integral control on the heating power based on the temperature difference to obtain the initial heating power. It should be understood by those skilled in the art that the heating power for proportional/integral control should be the heating power at the standard voltage, and as an exemplary embodiment, based on the current temperature difference, the heating apparatus performs proportional/integral control on the current heating power as the heating power at the standard voltage to obtain the initial heating power, and is influenced by the voltage fluctuation, the current input voltage may not be the standard voltage, and the current heating power may not be the heating power at the standard voltage under the condition that other conditions are the same for the same heated object (for example, the same volume of water, air, and the same amount of the same food material), and therefore, the initial heating power may have a deviation, may be larger or smaller, compared to the current actually required heating power. For convenience of understanding, for example, when the heating power of the heating device at the standard voltage is X, and the voltage fluctuates under otherwise the same conditions, so that the current actual heating power of the heating device is Y, the heating device performs proportional/integral control on the heating power by regarding the current actual heating power Y as the heating power X at the standard voltage based on the current temperature difference, but the current actually required heating power should be obtained by performing proportional/integral control on the heating power X at the standard voltage based on the temperature difference, so that when Y > X, the obtained initial heating power is larger, and when Y < X, the obtained initial heating power is smaller.

And S40, adjusting the initial heating power according to the input voltage to obtain the actual heating power. The initial heating power obtained by the steps may have deviation due to the influence of voltage fluctuation, so that the initial heating power is secondarily adjusted based on the input voltage, the actual heating power is closer to the heating power really required under the current temperature difference, the deviation of the regulating quantity caused by the voltage fluctuation is reduced, the adjusting accuracy of the heating equipment on the heating power is improved, the actual heating power is more accurate, and the temperature control is more reliable.

And S50, heating by using actual heating power. And aiming at the current temperature difference, the actual heating power after the secondary adjustment is used for heating, so that the temperature control is more accurate and reliable. It should be understood by those skilled in the art that the adjustment of the heating power is a dynamically controlled process, the larger the temperature difference, the higher the actual heating power, so as to effectively reduce the heating time, and as the heating progresses, the closer the current temperature is to the target temperature, the smaller the temperature difference, the lower the actual heating power, so as to effectively prevent scald caused by too fast temperature rise.

For the same heated object, under the same other conditions, the larger the target temperature value is, the larger the temperature difference is, the larger the initial heating power should be, however, in order to protect the elements in the circuit and prevent the safety hazard caused by too fast temperature rise, a preset power limiting value is provided, and different target temperatures correspond to different preset power limiting values, so as to serve as an exemplary embodiment, adjusting the initial heating power according to the input voltage includes: acquiring a preset power amplitude limit value corresponding to a target temperature; the initial heating power is limited below a preset power limit value based on the input voltage. As an exemplary embodiment, the different target temperature intervals correspond to different preset power limiting values, and the preset power limiting values should be smaller than the maximum power of the circuit element, for example, when the maximum power of the circuit element is 400W and the target temperature is less than 40 ℃, in order to prevent the potential safety hazard caused by too fast temperature rise, the preset power limiting values are 200W; when the target temperature value is 40-50 ℃, in order to prevent potential safety hazards caused by too fast temperature rise, the preset power limiting value is 250W; when the target temperature value is 50-70 ℃, in order to prevent potential safety hazards caused by too fast temperature rise, the preset power limiting value is 350W; when the target temperature is higher than 70 ℃, in order to protect elements in the circuit, the preset limiting value is 400W, and the initial heating power is adjusted to be lower than the preset limiting value based on the input voltage according to the actually set interval where the target temperature is located. For example, each target temperature may correspond to a preset power limit value, which improves the adjustment accuracy. As an exemplary embodiment, to achieve a fast adjustment of the current temperature to the target temperature, the adjusted initial heating power is close to the preset limiting value. It should be understood by those skilled in the art that the target temperature value and the corresponding preset limiting value in the above description are only examples for easy understanding, and the target temperature value and the preset limiting value may also be other values, which should not be taken as a limitation to the present application.

For a specific adjusting method for adjusting the initial heating power below the preset limit value based on the input voltage in order to reliably adjust the initial heating power, as an exemplary embodiment, the heating apparatus includes a controllable switching tube for adjusting the heating power, the controllable switching tube adjusts the initial heating power by a pulse width modulation signal, and the adjusting the initial heating power below the preset limit value based on the input voltage includes: the duty cycle of the pulse width modulated signal is adjusted based on the input voltage, wherein the duty cycle is inversely related to the input voltage. Therefore, the initial heating power of the heating device can be adjusted by adjusting the pulse width modulation signal through the controllable switching tube, under the condition that other conditions are the same for the same heated object, the larger the duty ratio of the pulse width modulation signal is, the larger the heating power of the heating device is, therefore, when the preset limiting value is not changed, the larger the input voltage is, the larger the initial heating power is, correspondingly, the smaller the duty ratio of the pulse width modulation signal is to be adjusted to adjust the initial heating power below the preset limiting value, and therefore, the duty ratio can be dynamically adjusted based on the input voltage, and the initial heating power of the heating device can be conveniently and reliably adjusted below the preset limiting value. It should be understood by those skilled in the art that the controllable switch tube may include a MOS tube, a thyristor or an I GBT controllable switch device.

To conveniently adjust the duty cycle of the pulse width modulated signal, illustratively, adjusting the duty cycle of the pulse width modulated signal based on the input voltage comprises: determining a voltage interval to which the input voltage belongs; duty cycles are determined based on input voltage intervals, wherein each voltage interval corresponds to at least one duty cycle. Therefore, the adjustment between the partitions can be realized, and the duty ratio is convenient to determine. As an exemplary embodiment, the controllable switching tube is a thyristor, the preset amplitude limit value is set to 400W, the temperature difference is set to 5 ℃, when the input voltage is 220V-230V, the initial heating power is 400W-450W, and the maximum output duty ratio of the thyristor at this time should be 88%, so that the actual heating power is adjusted from 400W-450W to below the preset amplitude limit value of 400W; when the input voltage is 230V-253V, the initial heating power is 450W-500W, and the maximum output duty ratio of the controllable silicon at the time is 80%, so that the actual heating power is adjusted from 450W-500W to be below a preset limiting value of 400W. It should be understood by those skilled in the art that the preset clipping values, temperature differences, input voltages, and initial heating powers in the above description are examples for easy understanding and should not be construed as limitations of the present application.

When the preset input voltage is a standard value, the initial heating power obtained through proportional/integral control adjustment should be equal to the actually required heating power, however, under the influence of voltage fluctuation, the input voltage may deviate from the preset input voltage, therefore, the deviation exists between the initial heating power and the actually required heating power, the larger the input voltage is, the larger the heating power before adjustment is, the larger the initial heating power is obtained by performing proportional/integral control adjustment on the heating power before adjustment, and vice versa, therefore, the larger the deviation of the input voltage from the preset input voltage is, the larger the deviation of the initial heating power from the actually required heating power is, the adjustment amount of the initial heating power is controlled according to the deviation of the input voltage and the preset input voltage, so that the adjusted initial heating power, namely the actual heating power is the same as the actually required heating power. Thus, as an exemplary embodiment, adjusting the initial heating power according to the input voltage comprises: comparing the input voltage with a preset input voltage; when the input voltage is greater than the preset input voltage, reducing the initial heating power; and when the input voltage is smaller than the preset input voltage, increasing the initial heating power, wherein the adjustment amplitude of the initial heating power is in positive correlation with the absolute value of the voltage difference between the input voltage and the preset input voltage. Therefore, the adjusted initial heating power, namely the actual heating power, can be the same as the really required heating power, so that the heating equipment is heated by the actual heating power, the influence caused by voltage fluctuation is reduced, the adjustment accuracy of the heating equipment on the heating power is improved, the actual heating power is more accurate, and the temperature control is more reliable.

In order to obtain the current temperature of the heated object, the heating device is usually provided with a temperature sensor, the temperature sensor usually has a sampling delay time length, and the proportional/integral control of the heating power is performed based on the temperature difference, so the selection of the control period of the proportional/integral control affects the dynamic control of the heating power and the adjustment accuracy of the heating power. For better understanding, taking an NTC temperature sensor as an example, assuming that the sampling delay time is 5 seconds, the current temperature is about to rise from 70 ℃ to 75 ℃, and if the control period is 1 second and is less than the sampling delay time, the temperature measured by the NTC temperature sensor is 70 ℃, and the actual temperature has reached 75 ℃, however, within the sampling delay time, the heating power is adjusted according to the current temperature of 70 ℃, the temperature difference is larger than the actual temperature difference, so that the adjusted heating power is larger, the heating power at the actual temperature of 75 ℃ is larger, and temperature control overshoot is caused, thereby having a potential safety hazard; if the control period is 10 seconds and is longer than the sampling delay time, the temperature measured by the NTC temperature sensor is 75 ℃, proportional/integral control is not started, heating power is adjusted according to the current temperature of 70 ℃, the temperature difference is smaller than the actual temperature difference, the adjusted heating power is smaller, the heating power is smaller when the actual temperature is 75 ℃, and the temperature control is too slow. Therefore, to ensure a fast control response speed while preventing temperature control overshoot, the control period needs to be greater than and close to the sampling delay period. As an exemplary embodiment, the proportional/integral control of the heating power based on the temperature difference includes: acquiring the sampling delay time of a temperature sensor; and determining a control period of proportional/integral control based on the delay time, wherein the control period is greater than the delay time, and the difference between the control period and the delay time is less than a preset value. The difference between the control period and the delay duration is set to be less than a preset value in order to make the control period close to the sampling delay duration.

In the prior art, heating power is generally controlled proportionally/integrally only by means of proportional parameters, so that the control speed of the heating power is possibly large or small in actual control, when the proportional parameters are too large, the control speed of the heating power is possibly large, the control system is possibly vibrated to cause temperature overshoot, and when the proportional parameters are too small, the control speed of the heating power is possibly small, the heating efficiency is possibly slowly adjusted, so that the proportional parameters are adjusted by means of the response time of the temperature sensor. The response time of the temperature sensor is the time required for reaching the thermal equilibrium between the temperature sensor and the measured medium, and the shorter the response time is, the higher the measurement precision of the temperature sensor is. The response time of the temperature sensor is introduced to adjust the proportional parameters, so that the proportional adjustment response speed is synchronous with the response speed area of the temperature sensor, namely, the shorter the response time of the temperature sensor is, the larger the proportional parameters can be; when the response time of the temperature sensor is longer, in order to prevent temperature overshoot caused by oscillation of a control system due to too fast proportional/integral control, the proportional parameter can be reduced, so that the accuracy of the proportional parameter can be improved, the control precision of heating power can be improved, and the accuracy of temperature control can be further improved.

In general, the response time of a temperature sensor is often related to the material, fabrication process, packaging and material of the temperature sensor itself, and thus, there is a nominal response time (typically measured in still air) for the temperature sensor. However, the inventors found that the response time of the temperature sensor also changes under the influence of external environmental factors of the temperature sensor. Therefore, in this embodiment, in order to improve the control accuracy of the heating power, when the proportional parameter is adjusted, the response time of the temperature sensor may be obtained in real time, and the proportional parameter is adjusted based on the real-time temperature response time, so as to determine the proportional parameter more accurately, and further adjust the temperature quickly and stably.

In some embodiments, the temperature response time of the temperature sensor may be affected by the properties of the measured medium itself, such as the density, material, specific heat capacity, and thermal conductivity of the measured medium, and generally, the smaller the density of the measured medium, the larger the specific heat capacity, the larger the thermal conductivity, and the shorter the time to reach thermal equilibrium between the temperature sensor and the measured medium, i.e., the shorter the response time. For example, the temperature response time of the same temperature sensor when measuring the temperature of air in an air fryer and an oven, the temperature of water in a water heater, and the temperature of food materials such as a soymilk maker and an electric cooker is often different due to the influence of the measured medium. In other embodiments, the temperature response time of the temperature sensor may also be affected by the real-time state of the measured medium, for example, the stability of the measured medium, for example, the static state and the flowing state of the medium have some influence on the response time of the temperature sensor, generally, the longer the measured medium flows, the longer the time to reach the thermal equilibrium between the temperature sensor and the measured medium, that is, the longer the response time, for example, the water in the water storage tank of the water heater is in the static state and the water adding/discharging state, the different stability of the water, and therefore, the different response time of the temperature sensor may be caused.

Therefore, in the present embodiment, the real-time temperature response time of the temperature sensor can be acquired. For example, the environmental factors of the temperature sensor, such as the measured media material information and the stability degree, may be obtained, and the nominal response time of the temperature sensor may be adjusted based on the media material information and the stability degree to obtain the real-time response time. For example, the adjustment is made in such a manner that the thermal conductivity, the degree of stability and the response time are inversely related. After the real-time temperature response time is obtained, the proportional parameter in the proportional/integral control can be controlled to be adjusted along with the real-time temperature response time, wherein the proportional parameter is inversely related to the real-time temperature response time. The proportional parameters can be adjusted according to the real-time temperature response time of the temperature sensor, and temperature overshoot or too low heating efficiency caused by oscillation of a control system due to large or small control speed when proportional/integral control is carried out on heating power in actual control is avoided. As an exemplary embodiment, the proportional parameter may be adjusted in real time by a fixed proportional relationship, a fixed value relationship, or a dynamically changing relationship with the real-time response time.

It will be appreciated by those skilled in the art that the control period of the proportional/integral control determines the duration of the interval for each control, and the proportional parameter of the proportional/integral control determines the response speed of the control adjustment of the heating power in a single control.

It should be understood by those skilled in the art that proportional control is a deviation of a proportional reaction system, once the deviation occurs in the system, the proportional control immediately generates an adjusting effect to reduce the deviation, the proportional effect is large, the adjustment can be accelerated, the error can be reduced, but the residual error can be caused; the integral control is to make the system eliminate the steady-state error and improve the tolerance, because with the error, the integral control is performed until there is no difference, the integral control is stopped, but the integral control may inhibit the adjusting time of the temperature, therefore, in order to speed up the adjustment, reduce the heating time, and reduce the error, as an exemplary embodiment, the proportional/integral control of the heating power based on the temperature difference includes: judging whether the temperature difference is larger than a preset temperature difference or not; when the temperature difference is larger than the preset temperature difference, the heating power is adjusted by adopting proportional control; and when the temperature difference is smaller than the preset temperature difference, the heating power is adjusted by adopting integral control. Therefore, when the temperature difference is large, the heating power is adjusted by adopting proportional control, the adjusting amplitude is large, the adjustment can be accelerated, the time for the current temperature to reach the target temperature is reduced, the heating time is reduced, the temperature difference can not be eliminated by proportional control, and the temperature difference exists all the time, so that when the temperature difference is small, the integral control is used for adjusting the heating power, the integral control is carried out as long as the temperature difference exists, and the integral control is carried out until the current temperature reaches the target temperature and the temperature difference does not exist, so that the adjustment can be accelerated, the heating time is shortened, and the temperature difference can be reduced to no difference.

In order to obtain the input voltage of the heating device safely and reliably, as an exemplary embodiment, referring to fig. 2, obtaining the input voltage includes:

s11, heating the heated object in the heating equipment with preset heating power. As an exemplary embodiment, the preset power may be set by a user's active operation, and after determining the preset power, the heating device heats the heated object at the preset power. The user can set the preset power through a key, touch or remote control mode.

S12, temperature change information of the heated object in the heating process and used for representing the temperature rise rate is obtained. As an exemplary embodiment, the temperature change information of the heated object for characterizing the temperature increase rate may include information such as a temperature increase period or a temperature change rate of the heated object. For example, the heating time length of the heated object in a certain temperature interval can be acquired as the temperature change information representing the heating rate, and those skilled in the art can understand that in the same temperature interval, the longer the heating time length is, the lower the heating rate is; the shorter the temperature rise time, the higher the temperature rise rate. For example, the temperature change value of the heated object in a certain time period can be acquired as the temperature change information representing the heating rate, and a person skilled in the art can understand that in the same time period, the larger the temperature change value is, the larger the temperature change rate is, and the higher the heating rate is; the smaller the temperature change value, the smaller the temperature change rate, and the lower the temperature rise rate.

And S13, determining the input voltage based on the temperature change information. As will be understood by those skilled in the art, for the same heated object (e.g., the same volume of water, air, the same amount of the same food material) under otherwise identical conditions, the greater the actual heating power, the higher the rate of temperature rise, and the power from the heating device: and the larger the input voltage of the heating equipment is, the larger the heating power is, and the higher the temperature rise rate is. Therefore, the current input voltage can be determined through the temperature rise rate detection, and further, the input voltage of the heating equipment can be determined through the temperature change information of the heated object for representing the temperature rise rate, so that the increase of the hardware design cost is avoided, the input voltage of the heating equipment can be detected at low cost, the working reliability of the whole heating equipment is improved, and the heating equipment can be safely and conveniently controlled to heat.

In one embodiment, the heating apparatus includes a temperature sensor, and acquiring temperature change information of the heated object during heating for characterizing a temperature rise rate includes: counting a heating-up time period for heating up the heated object from a first preset temperature to a second preset temperature, wherein the first preset temperature and the second preset temperature are determined based on the attribute of the temperature sensor; temperature change information is calculated based on the temperature rise time period.

As can be appreciated by those skilled in the art, the properties of the temperature sensor in different temperature intervals may be different, such as the temperature measurement accuracy of the temperature sensor in different temperature intervals, the resolution in different temperature intervals, the change rate of the parameter change curve in different temperature intervals, the response speed in different temperature intervals, and the like. As an exemplary embodiment, a low-cost and reliable NTC temperature sensor may be adopted, and the first predetermined temperature and the second predetermined temperature are determined by using the property that the change rate of the resistance change curve of the NTC temperature sensor in different temperature intervals is different, and it can be understood by those skilled in the art that the resistance of the NTC temperature sensor may be represented by a temperature digital quantity AD value, referring to fig. 3, as can be known from the relationship between the temperature and the temperature digital quantity AD value of the NTC temperature sensor, when the temperature changes from 0 ℃ to 30 ℃, the temperature digital quantity AD value changes very little with the temperature rise; when the temperature is changed from 30-80 ℃, the AD value of the temperature digital quantity is changed uniformly along with the temperature rise, and the change rate is stable and is changed linearly; when the temperature changes from 80 ℃ to 100 ℃, the digital temperature value AD changes in a curve with the temperature, and the change is small, so that the NTC temperature sensor has different rates of change of the digital temperature value AD in different temperature intervals, and it can be understood by those skilled in the art that the more uniform the change of the digital temperature value AD is, the higher the resolution of the NTC temperature sensor is, the more accurate the recognized temperature is, and thus the more accurate the calculated heating time for heating from the first predetermined temperature to the second predetermined temperature within a certain time is, so that the first predetermined temperature and the second predetermined temperature can be selected within a temperature interval of 30 ℃ to 80 ℃, and the first predetermined temperature is less than the second predetermined temperature, and exemplarily, the first predetermined temperature and the second predetermined temperature are 30 ℃ and 80 ℃, 45 ℃ and 70 ℃, 50 ℃ and 65 ℃, respectively. Taking water as the heated object, as an exemplary embodiment, the temperature of tap water is generally less than 45 ℃, so the first predetermined temperature may be 45 ℃ and the second predetermined temperature may be 80 ℃, whereby the time counting is started when the heating device heats the water to 45 ℃ and stopped when the temperature of the water reaches 80 ℃, resulting in the length of the temperature rise.

As will be understood by those skilled in the art, the temperature-increasing rate (second predetermined temperature — first predetermined temperature)/temperature-increasing period may be indirectly used to characterize the magnitude of the temperature-increasing rate, and thus the temperature change information can be calculated based on the temperature-increasing period.

As to how to determine the input voltage based on the temperature change information, as an exemplary embodiment, when the heated object is warmed up from the first predetermined temperature to the second predetermined temperature, the warming time period is different, the warming rate is different, and correspondingly, the input voltage of the heating device is different, and therefore, the input voltage of the heating device may be determined based on the warming time period. Taking water as a heated object, as an exemplary embodiment, when the input voltage is 220V, the actual power of the heating device is 1500W, the timing is started when the heating device heats the water to 45 ℃, and the timing is stopped when the temperature of the water reaches 80 ℃, so that the temperature rise time is 4 minutes and 27 seconds, and the condition that the voltage fluctuation of the commercial power voltage is +/-15% is simulated is obtained, and the temperature rise time required for raising the temperature of the water from 45 ℃ to 80 ℃ under different input voltages is measured according to experiments with reference to table 1.

Input voltage	Actual power	Length of time of temperature rise
			187V	1030W	6 minutes and 9 seconds
200V	1220W	5 minutes and 20 seconds
			220V	1520W	4 minutes and 27 seconds
230V	1630W
			3 minutes and 54 seconds
253V	1800W
			3 minutes and 10 seconds

TABLE 1

Therefore, referring to table 1, the actual input voltage range of the heating device can be determined according to the temperature rise time range required by the temperature rise from 45 ℃ to 80 ℃, along with the improvement of data accuracy, the input voltage of the heating device can be determined according to the temperature rise time, the increase of hardware design cost is avoided, the input voltage of the heating device is detected at low cost, the working reliability of the whole heating device is improved, and the heating device can be safely and conveniently controlled to heat.

In an exemplary embodiment, in order to reduce the time for the current temperature to reach the target temperature and improve the heating efficiency, when the temperature difference between the current temperature and the target temperature reaches a certain value (e.g., 10 ℃, 7 ℃, 5 ℃, 2 ℃, etc.), the step of performing proportional/integral control on the heating power based on the temperature difference to obtain the initial heating power is triggered.

It should be understood by those skilled in the art that the above-mentioned temperature control method for a heating device may be applicable to an application scenario of functions of the heating device, such as heat preservation, boiling, etc., in the application scenario of the heat preservation function, the target temperature may be a temperature selected by a user, and in the application scenario of the boiling function, the target temperature may be a boiling point temperature.

However, when the boiling function is implemented, a temperature overshoot phenomenon generally occurs, for example, a water heater may cause a large amount of steam when the temperature overshoot occurs, and thus a safety accident such as scalding of a user may be caused, and in order to prevent the temperature overshoot and improve the experience of the user, the temperature control method further includes: acquiring a heating boiling instruction; judging whether the current temperature reaches a preset temperature, wherein the preset temperature is less than the boiling temperature; and when the current temperature reaches the preset temperature, switching to power limiting heating, and adjusting the current heating power of the heating equipment to be within a preset heating power range based on the input voltage, wherein the preset temperature is in positive correlation with the quantity of the heated objects.

It will be appreciated by those skilled in the art that the preset temperature is greater than the second predetermined temperature. Taking a water heater as an example, as an exemplary embodiment, the preset temperature should be greater than the second preset temperature and less than the boiling temperature of water, when the second preset temperature is 80 ℃, the preset temperature is set to 87 ℃, when the water temperature reaches the second preset temperature of 80 ℃, the input voltage can be obtained, the actual heating power is obtained, then the heating is continued, when the water temperature reaches and exceeds 87 ℃, the actual heating power is reduced based on the actual input voltage and adjusted to be within the preset heating power range, and the temperature overshoot can be prevented. Taking a water heater as an example, under the same heating power, the more the water volume is, the larger the required heat is, and the longer the required heating time is, and when the current temperature reaches the preset temperature, the power will be started to be heated, and in order to reduce the time to reach the target temperature, the more the water volume is, the larger the preset temperature is, and therefore, the preset temperature is positively correlated with the quantity of the heated object, and the heating efficiency can be improved.

The technical staff in the field can understand that when the current temperature reaches the preset temperature, the heating is switched to the limited power heating, the current heating power of the heating equipment is adjusted to the preset heating power range based on the input voltage, the actual input voltage of the heating equipment can be different, the actual heating power is adjusted to the preset power range all the time based on the actual input voltage, the adjusting process is more accurate, the heating power is more accurate, and the accuracy of temperature control is improved. Taking water as a heated object, as an exemplary embodiment, when a heating device is connected to a 220V mains supply voltage to work, when the water temperature reaches 80 ℃, the actual input voltage obtained by the temperature control method is 200V, the actual heating power of the heating device is 1220W at this time, if the heating device continues to heat with the 1220W heating power, the temperature may rise too fast, which may cause a splashing phenomenon after the water boils, scald a user, and affect the use feeling of the user, so that the actual heating power of 1220W is reduced based on the 200V actual input voltage, and is adjusted to be within a preset heating power range; when the actual input voltage obtained by the temperature control method is 187V, the actual heating power of the heating equipment is 1030W, if the heating equipment continues to heat with the heating power of 1030W, the heating equipment may be heated too fast, so that the phenomenon of splashing after water boils can be caused, a user is scalded, and the use feeling of the user is influenced, therefore, the actual heating power of 1030W is reduced based on the actual input voltage of 187V, and the actual heating power is adjusted to be within the preset heating power range; the same applies when the actual input voltage obtained by the temperature control method is other values. Therefore, the temperature control method in the embodiment can enable the adjustment process to be more accurate, so that the heating power of the heating equipment is more accurate, the water temperature is more accurately controlled, and the user experience is improved.

In order to shorten the heating time, accelerate the heating efficiency, and improve the user experience, in an embodiment, when the current temperature does not reach the preset temperature, the heating device is controlled to heat at the full power, wherein the third preset temperature is less than the preset boiling point temperature, and the maximum power within the preset heating power range is less than the full power.

Therefore, before boiling, the heating equipment is controlled to heat with full power, the heating time is shortened, the heating equipment is about to boil when the heating temperature reaches and exceeds the preset temperature, the heating power of the heating equipment is reduced, the heating power is adjusted to be within the range of the preset heating power, temperature overshoot is prevented, and the user experience is improved. Taking a water heater as an example, as an exemplary embodiment, the preset temperature is set to 90 ℃, the heating device is controlled to perform full-power heating with the current actual power, so that the water temperature quickly reaches and exceeds 90 ℃, and when the water is about to boil, the heating device is controlled to enter a step of adjusting the actual heating power of the heating device to be within the preset heating power range based on the input voltage, namely, the actual heating power is reduced, and the actual heating power is adjusted to be within the preset heating power range, so that temperature overshoot is prevented.

It should be understood by those skilled in the art that the preset temperature set to 87 ℃ or 90 ℃ in the above description is only an exemplary example for easy understanding, and the preset temperature may be other values greater than the second predetermined temperature.

In order to facilitate reliable adjustment of the heating power, in one embodiment the heating device comprises a controllable switching tube for adjusting the heating power, the controllable switching tube adjusting the heating power by a pulse width modulation signal; adjusting the actual heating power of the heating device to within the preset heating power range based on the input voltage comprises: the duty cycle of the pulse width modulated signal is adjusted based on the input voltage, wherein the duty cycle is inversely related to the input voltage. Therefore, the heating power of the heating equipment can be adjusted by adjusting the pulse width modulation signal through the controllable switching tube, the larger the duty ratio of the pulse width modulation signal is, the larger the heating power of the heating equipment is, therefore, when the preset heating power range is not changed, the larger the actual input voltage is, the larger the actual heating power of the heating equipment is, correspondingly, the smaller the duty ratio of the pulse width modulation signal needs to be adjusted to adjust the actual heating power to the preset heating power range, and therefore, the duty ratio is adjusted dynamically based on the input voltage, and the purpose of adjusting the actual heating power of the heating equipment to the preset heating power range is achieved conveniently and reliably. It should be understood by those skilled in the art that the controllable switch tube may include a MOS tube, a thyristor or an IGBT.

To facilitate adjusting the duty cycle of the pulse width modulated signal, in one embodiment, adjusting the duty cycle of the pulse width modulated signal based on the input voltage comprises: determining a voltage interval to which the input voltage belongs; duty cycles are determined based on input voltage intervals, wherein each voltage interval corresponds to at least one duty cycle. Therefore, the adjustment between the partitions can be realized, and the duty ratio is convenient to determine. As an exemplary embodiment, the controllable switching tube is a thyristor, referring to table 1, the preset heating power range is set to about 400W, when the input voltage is about 180V to 187V, the actual heating power is about 1030W, and the maximum output duty ratio at this time should be 38%, so that the actual heating power is adjusted from 1030W to within the preset heating power range of about 400W; when the input voltage is 187-200V, the actual heating power is 1030W-1220W, and the maximum output duty ratio of the controllable silicon is 32% at the moment, so that the actual heating power is adjusted from 1030W-1220W to a preset heating power range of about 400W; when the input voltage is 200V-220V, the actual heating power is 1220W-1520W, and the maximum output duty ratio of the controllable silicon is 26% at the moment, so that the actual heating power is adjusted to about 400W from 1220W-1520W; when the input voltage is 220-230V, the actual heating power is 1520-1630W, and the maximum output duty ratio of the controllable silicon is 24% at the moment, so that the actual heating power is adjusted from 1520-1630W to a preset heating power range of about 400W; when the input voltage is 230V-253V, the actual heating power is 1630W-1800W, and the maximum output duty ratio of the controllable silicon at the moment is 22%, so that the actual heating power is adjusted from 1630W-1880W to a preset heating power range of about 400W.

It will be appreciated by those skilled in the art that the above temperature control method is also applicable to the application scenario of the boiling point determination function when the boiling function is implemented.

Taking an application scenario that the heating device performs a boiling point determination function as an example: in general, when heating equipment is used for heating, altitude factors are considered so as to clarify the boiling point temperature of an area where the equipment is located, the higher the altitude is, the lower the boiling point is, if the boiling point is not clarified, the heating temperature is set too low to cause water not to be boiled, and the heating temperature is set too high to cause the actual temperature of water never to reach the set heating temperature, so when the heated object is water, taking a water heater as an example, optionally, the temperature control method further includes: and continuously heating with the heating power within the preset heating power range and collecting the boiling point. Therefore, the heating device can stop heating after the water temperature reaches the boiling point, and the next procedure is started.

As an exemplary embodiment, when the boiling point determining function is performed, the preset temperature should be close to the boiling point temperature corresponding to the highest altitude to which the heating apparatus can be adapted, and referring to table 2, table 2 is the boiling point temperature of water at different altitudes, and as can be seen from table 2, if the heating apparatus is set to be used at an altitude of 3000m or less, in order to prevent a user from being scalded by a large amount of steam generated when water is boiled due to temperature overshoot, the preset temperature should be set to a value lower than 91 ℃, and the preset temperature should be greater than the second predetermined temperature and smaller than the boiling point temperature, and therefore, when the second predetermined temperature is 80 ℃, the preset temperature may be set to a temperature value greater than 80 ℃ and smaller than 91 ℃, for example, temperature values such as 81 ℃, 83 ℃, 85 ℃, 87 ℃, 90 ℃ and the like. If the heating apparatus is configured to be used at an altitude of 5000m or less, the preset temperature may be set to a temperature value greater than 75 ℃ and less than 83 ℃, for example, 76 ℃, 77 ℃, 79 ℃, 82 ℃ or the like, when the second predetermined temperature is 75 ℃.

Altitude height	Boiling point temperature
		0m
	100℃
		1500m	95℃
2000m	93℃
		3000m
	91℃
		4000m
	88℃
		5000m	83℃

TABLE 2

Taking a water heater as an example, when a heating device works, when the water temperature reaches and exceeds a preset temperature, and the time length for which the water temperature is kept unchanged exceeds a preset time length, that is, the current temperature is kept as a boiling point temperature, as an exemplary embodiment, the preset temperature is 87 ℃, the preset time length is 2 minutes, the heating device is provided with a hot tank for storing water, when the heating device is used for the first time, half tank of water is supplemented to the hot tank, the heating efficiency is improved, the waiting time of a user is reduced, when the water temperature exceeds 87 ℃, the heating device reduces the heating power, the heating power is controlled within a preset heating power range, and when the water temperature exceeds 87 ℃ and the time length kept at 95 ℃ exceeds 2 minutes, 95 ℃ is kept as the boiling point temperature. Thus, as an exemplary embodiment, when the water temperature exceeds the preset temperature, it is determined whether the heating device stores the boiling point temperature, if not, the above procedure of confirming the boiling point temperature is performed, if so, it is determined whether the water temperature reaches the boiling point temperature, and if the water temperature reaches the boiling point temperature, the heating device is controlled to stop heating or perform the next heating procedure.

It should be understood by those skilled in the art that the values and value ranges in all the above examples are only illustrative examples for easy understanding, and the protection scope in the present embodiment is not limited to the values and value ranges in all the above examples.

An embodiment of the present application further provides a heating device, and fig. 4 is a schematic structural diagram of the heating device in an embodiment of the present application; fig. 5 is a schematic diagram of a control circuit of a heating apparatus according to an embodiment of the present application.

Referring to fig. 4, the heating apparatus comprises a processor, a memory and executable instructions stored on the memory, the executable instructions being arranged to, when executed by the processor, cause the heating apparatus to perform the temperature control method described above.

Referring to fig. 5, exemplary, the heating apparatus further includes: the heating circuit comprises a heating body R1 and a temperature sensor which are arranged inside the water storage device, and a heating power switching module which is connected with the heating body R1 in series, wherein the heating power switching module is controlled by a processor and used for adjusting heating power and comprises a first switch S1, a second switch S2 and a controllable switch tube S3, and the second controllable switch is connected with the controllable switch tube S3 in series and connected with the first switch S1 in parallel. As an exemplary embodiment, since there is a significant difference between a large relay and a small relay in cost, the first switch S1 and the second switch S2 are set as relays having different sizes, the first switch S1 is a large relay, the second switch S2 is a small relay, and the controllable switch tube S3 is set as a thyristor, so that the heating apparatus controls the heating body R1 to heat in a hardware design manner that the small relay is connected in series with the thyristor and then connected in parallel with the large relay, so that, when the heating apparatus is operated, the large relay is turned on to operate at full power during heating from room temperature to a preset temperature, and the small relay is connected in series with the thyristor to control the heating body R1 to heat at low power, so as to achieve precise and smooth heating from the preset temperature to a boiling temperature, in some embodiments, the heating body R1 has a rated voltage of 220V and a rated power of 1500W, thereby, the large relay with the parameter of 16A is selected to control full-power heating, the control power of the small relay is set to be about 400W at most and 26.6 percent of rated power in order to reduce cost, and the small relay with the parameter of 10A is selected to control small-power heating. In some embodiments, the temperature sensor is an NTC temperature sensor probe.

The heating device also illustratively includes a memory and bus, and additionally allows for the inclusion of hardware required for other services. The memory may include both memory and non-volatile memory (non-volatile memory) and provides execution instructions and data to the processor. Illustratively, the Memory may be a high-speed Random-Access Memory (RAM), and the non-volatile Memory may be at least 1 disk Memory.

Wherein the bus is used to interconnect the processor, the memory, and the network interface. The bus may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, an EISA (Extended Industry Standard Architecture) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one double-headed arrow is shown in FIG. 4, but this does not indicate only one bus or one type of bus.

In a possible implementation manner of the heating device, the processor may first read the corresponding execution instruction from the non-volatile memory to the memory and then operate the corresponding execution instruction, or may first obtain the corresponding execution instruction from another device and then operate the corresponding execution instruction. The processor, when executing the execution instructions stored in the memory, can implement any of the heating apparatus control methods described above in this disclosure.

It will be understood by those skilled in the art that the above-described temperature control method of the heating apparatus can be applied to a processor, and can also be implemented by means of the processor. Illustratively, the processor is an integrated circuit chip having the capability to process signals. In the process of executing the partition identification method by the processor, the steps of the partition identification method can be completed by an integrated logic circuit in the form of hardware or an instruction in the form of software in the processor. Further, the Processor may be a general-purpose Processor, such as a Central Processing Unit (CPU), a Network Processor (NP), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, a microprocessor, or any other conventional Processor.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above are merely examples of the present invention, and are not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method of temperature control, adapted for use with a heating apparatus, comprising:

acquiring an input voltage of the heating equipment;

acquiring the temperature difference between the current temperature and the target temperature;

carrying out proportional/integral control on the heating power based on the temperature difference to obtain initial heating power;

adjusting the initial heating power according to the input voltage to obtain actual heating power;

and heating by utilizing the actual heating power.

2. The method of claim 1, wherein said adjusting the initial heating power based on the input voltage comprises:

acquiring a preset power amplitude limit value corresponding to the target temperature;

limiting the initial heating power below the preset power limit value based on the input voltage.

3. The method of claim 1, wherein said adjusting the initial heating power based on the input voltage comprises:

comparing the input voltage with a preset input voltage;

when the input voltage is greater than the preset input voltage, reducing the initial heating power;

and when the input voltage is smaller than the preset input voltage, increasing the initial heating power, wherein the adjustment amplitude of the initial heating power is positively correlated with the absolute value of the voltage difference between the input voltage and the preset input voltage.

4. The temperature control method of claim 1, wherein said obtaining the input voltage comprises:

heating the heated material in the heating device with preset heating power;

acquiring temperature change information of the heated object for representing the heating rate in the heating process;

determining the input voltage based on the temperature change information.

5. The temperature control method according to claim 1, wherein the proportional/integral control of the heating power based on the temperature difference comprises:

acquiring the sampling delay time of a temperature sensor;

and determining a control period of proportional/integral control based on the delay time length, wherein the control period is greater than the delay time length, and the difference between the control period and the delay time length is less than a preset value.

6. The temperature control method according to claim 1, wherein the proportional/integral control of the heating power based on the temperature difference comprises:

acquiring real-time temperature response time of a temperature sensor;

and controlling a proportional parameter in the proportional/integral control to adjust along with the real-time temperature response time, wherein the proportional parameter is inversely related to the real-time temperature response time.

7. The temperature control method according to claim 1, wherein the proportional/integral control of the heating power based on the temperature difference comprises:

judging whether the temperature difference is larger than a preset temperature difference or not;

when the temperature difference is larger than a preset temperature difference, the heating power is adjusted by adopting proportional control;

and when the temperature difference is smaller than the preset temperature difference, adjusting the heating power by adopting integral control.

8. The temperature control method according to any one of claims 1 to 7, further comprising:

acquiring a heating boiling instruction;

judging whether the current temperature reaches a preset temperature or not, wherein the preset temperature is less than a boiling temperature;

when the current temperature reaches the preset temperature, switching to power-limiting heating, and adjusting the current heating power of the heating equipment to be within a preset heating power range based on the input voltage, wherein the preset temperature is positively correlated with the quantity of the heated objects.

9. The temperature control method of claim 8, further comprising:

and continuously heating with the heating power within the preset heating power range and collecting the boiling point.

10. A heating device, comprising a processor, a memory, and executable instructions stored on the memory, the executable instructions being arranged to, when executed by the processor, cause the heating device to perform the temperature control method of any one of claims 1 to 9.