Electric heating device and control method therefor

Abstract

The present application relates to the technical field of heating apparatuses. Disclosed are an electric heating device and a control method therefor. The electric heating device comprises: a housing, comprising a mounting cavity; a plurality of heating members, arranged at intervals in the heating cavity; a temperature sensor, arranged at a water outlet end of the housing; and a controller, an information input end of the controller being in communication connection with the temperature sensor so as to receive temperature information output by the temperature sensor, and a control output end of the controller being in communication connection with power supply ends of the plurality of heating members so as to control the connection or disconnection of the power supply end of each heating member on the basis of the received temperature information.

Description

Electric heating device and control method thereof

[0001] This application is based on and claims priority to Chinese Patent Application No. 202411096533.4, filed on August 9, 2024, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of heating equipment, for example, to an electric heating device and a control method thereof. BACKGROUND

[0003] At present, many hot water supply devices, such as electric heating pipes and water heaters, are provided with multiple heat sources to simultaneously heat to improve heating efficiency. Such electric heating devices are usually preset with a heating temperature value, such as a target temperature value a ℃. When the water temperature is lower than the heating temperature value, multiple heat sources are turned on to heat the water body, thereby achieving hot water supply.

[0004] In the implementation of the above-mentioned embodiments, it is found that multiple heat sources are simultaneously heated, which improves the heating efficiency, but the temperature control precision is low, and energy waste is easily caused, so the reliability is low. Specifically, when the difference between the heating temperature value and the target temperature value is small, multiple heat sources will be frequently started and stopped, which increases power consumption. Moreover, since multiple heat sources are simultaneously heated, the heating power is large, and when the outlet water temperature gradually approaches the target temperature value, the target temperature is easily deviated, which causes the outlet water temperature to be too high, the outlet water temperature fluctuates greatly, and the temperature control precision is low. In summary, multiple heat sources are simultaneously heated, which has low reliability.

[0005] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an overall description of the application, nor is it intended to determine key / important elements or delineate the scope of these embodiments, but as a prelude to the detailed description below.

[0007] The disclosed embodiments provide an electric heating device and a control method thereof, which can improve the temperature control precision and energy utilization rate of the electric heating device, thereby improving the reliability of the electric heating device.

[0008] In some embodiments, an electric heating device is provided, comprising: a housing comprising a mounting cavity; a plurality of heating elements arranged at intervals in the heating cavity; a temperature sensor arranged at a water outlet end of the housing; a controller, an information input end of the controller being in communication connection with the temperature sensor to receive temperature information output by the temperature sensor; and a control output end of the controller being in communication connection with a power supply end of each of the plurality of heating elements to control the power supply end of each of the plurality of heating elements to be turned on or turned off according to the received temperature information.

[0009] In some embodiments, a control method of an electric heating device is provided, the electric heating device comprising a housing and a plurality of heating elements, the housing comprising a mounting cavity, and the plurality of heating elements being arranged at intervals in the heating cavity; the control method comprising: obtaining a water outlet temperature of the electric heating device and a heating time length of the heating elements; obtaining a first temperature difference between a target temperature and the water outlet temperature; determining a target number of the heating elements to be turned on according to the first temperature difference and the heating time length and controlling a corresponding number of the heating elements to be turned on; and controlling all of the heating elements to be turned off when the first temperature difference is less than or equal to a first temperature difference threshold.

[0010] The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application. BRIEF DESCRIPTION OF DRAWINGS

[0011] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are schematic and are not intended to be limiting of the embodiments, in which like reference numerals denote like elements, and in which:

[0012] Fig. 1 is a structural schematic diagram of an electric heating control device according to an embodiment of the present disclosure;

[0013] Fig. 2 is a structural schematic diagram of an electric heating control device according to another embodiment of the present disclosure;

[0014] Fig. 3 is a control principle schematic diagram of an electric heating control device according to an embodiment of the present disclosure;

[0015] Fig. 4 is a control principle schematic diagram of an electric heating control device according to another embodiment of the present disclosure;

[0016] Fig. 5 is a structural schematic diagram of a controller according to an embodiment of the present disclosure;

[0017] Fig. 6 is a schematic diagram of a control method of an electric heating device according to an embodiment of the present disclosure;

[0018] Fig. 7 is a schematic diagram of a control method of an electric heating device according to another embodiment of the present disclosure;

[0019] Fig. 8 is a schematic diagram of a control method of an electric heating device according to another embodiment of the present disclosure.

[0020] Reference numerals: 1 Electric heating device; 10 Housing; 102 Heating chamber; 104 Water outlet; 106 Water inlet; 20 Heating element; 30 Power switch; 40 Power switch; 50 Temperature sensor; 60 Thermostat; 602 Temperature probe; 70 Water level detection device; 702 Water level sensor; 704 Flow meter; 80 Controller; 800 Processor; 801 Memory; 802 Communication interface; 803 Bus; 2 Power supply. Detailed Implementation

[0021] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0022] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0023] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0024] In addition, the terms "set", "connected", and "fixed" should be understood broadly. For example, "connected" can be fixed connection, detachable connection, or integral configuration; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium, or internal communication between two devices, elements or components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present disclosure according to the specific circumstances.

[0025] Unless otherwise specified, the term "plurality" means two or more.

[0026] In the embodiments of the present disclosure, the character " / " represents an "or" relationship between the preceding and following objects. For example, A / B means A or B.

[0027] The term "and / or" is a description of the association between objects, which means that there can be three relationships. For example, A and / or B means that there are three relationships of A, B, and A and B.

[0028] The term "corresponding" can refer to an association or binding relationship. A and B correspond to each other means that there is an association or binding relationship between A and B.

[0029] It should be noted that the embodiments in the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0030] In combination with FIG. 1 and FIG. 2, the embodiments of the present disclosure provide an electric heating device 1, which includes a shell 10, a plurality of heating elements 20, a temperature sensor 50, and a controller 80. The shell 10 includes a heating cavity 102. The plurality of heating elements 20 are arranged at intervals in the heating cavity 102. The temperature sensor 50 is arranged at a water outlet end 104 of the shell 10. An information input end of the controller 80 is in communication connection with the temperature sensor 50 to receive temperature information output by the temperature sensor 50. A control output end of the controller 80 is in communication connection with a power supply end of each of the plurality of heating elements 20 to control the conduction or disconnection of the power supply end of each of the heating elements 20 according to the received temperature information.

[0031] In this embodiment, the shell 10 defines a heating cavity 102 for buffering water. The heating element 20 is used to heat the water. The temperature sensor 50 is used to collect temperature information and transmit the collected temperature information to the controller 80. The information input end of the controller 80 is in communication connection with the temperature sensor 50 to receive the temperature information output by the temperature sensor 50. The control output end of the controller 80 is in communication connection with the power supply end of the plurality of heating elements 20 to control the conduction or disconnection of the power supply end of each heating element 20 according to the received temperature information, thereby controlling the power supply state of each heating element 20 and realizing the independent start and stop of each heating element 20. By realizing the independent start and stop of each heating element 20, multi-stage heating of the electric heating device 1 is realized to flexibly adjust the heating power of the electric heating device 1, avoid the water temperature deviating from the target temperature, and improve the temperature control accuracy of the electric heating device 1 while avoiding unnecessary energy waste. In summary, the electric heating device 1 of the embodiment of the present disclosure has higher reliability.

[0032] In practical applications, the heating element 20 can be a resistance wire, a ceramic heater, a PTC (Positive Temperature Coefficient) thermistor, or other types of electric heating elements. The specific type of heating element 20 is not limited in the present application.

[0033] Optionally, as shown in FIGS. 1 and 2, the heating element 20 is arranged along the length direction of the shell 10.

[0034] In this embodiment, by arranging the heating element 20 along the length direction of the shell 10, a uniform heating area is formed in the heating cavity 102, ensuring uniform heating of the water body and avoiding water temperature stratification, thereby improving heating efficiency and water temperature stability.

[0035] In some embodiments, as shown in FIGS. 3 and 4, the plurality of heating elements 20 are connected in parallel. In this embodiment, the plurality of heating elements 20 are connected in parallel to realize the independent start and stop of the heating element 20.

[0036] Optionally, as shown in FIGS. 1 to 4, the electric heating device 1 further comprises a plurality of power supply switches 30. The opposite ends of the power supply switch 30 are respectively electrically connected with the power supply source 2 and the power supply end of the heating element 20. The plurality of power supply switches 30 are arranged one by one corresponding to the plurality of heating elements 20. The control output end of the controller 80 is in communication connection with the plurality of power supply switches 30 to control the conduction or disconnection of each power supply switch 30 according to the received temperature information.

[0037] The codes and their meanings, explanations involved in FIGS. 3 and 4 are shown in Table 1.

[0038] Table 1

[0039] The plurality of power switches 30 are power switch 1# (KM1), power switch 2# (KM2), power switch 3# (KM3), power switch 4# (KM4), power switch 5# (KM5) and power switch 6# (KM6) respectively.

[0040] The plurality of heating elements 20 are heating element 1# (R1), heating element 2# (R2), heating element 3# (R3), heating element 4# (R4), heating element 5# (R5) and heating element 6# (R6) respectively.

[0041] The power supply 2 refers to a device or system that provides the required electrical energy for various electrical equipment, machines or systems. The power supply 2 can convert other forms of energy (such as chemical energy, mechanical energy, solar energy, wind energy, etc.) into electrical energy, or transform, distribute and regulate the electrical energy in the power grid to meet the power demand of different equipment or systems. In this application, the power supply 2 is used to provide electrical energy for the electric heating device 1.

[0042] In this embodiment, the controller 80 is used to generate control signals to control the power on or off of the power switches 30. The opposite ends of each power switch 30 are electrically connected to the power supply 2 and the power supply end of the corresponding heating element 20, respectively, thereby realizing independent control of the power supply of a single heating element 20 and improving the flexibility and accuracy of the heating control of the electric heating device 1.

[0043] Optionally, the power switch 30 includes an AC contactor. The opposite ends of the AC contactor are electrically connected to the power supply 2 and the power supply end of the heating element 20, respectively. A plurality of AC contactors are arranged one-to-one corresponding to a plurality of heating elements 20. The control output end of the controller 80 is in communication connection with the plurality of AC contactors to control the conduction or disconnection of each AC contactor according to the received temperature information.

[0044] The AC contactor is an electrical element used to control the on-off of large current, which has the characteristics of large control power, frequent operation and long service life. In this embodiment, the AC contactor is used as the power switch 30 to utilize the characteristics of the AC contactor and improve the reliability of the heating control of the electric heating device 1. In addition, the AC contactor has functions such as short circuit protection and overload protection. When the heating element 20 appears abnormal (such as short circuit, overload, etc.), the AC contactor can quickly cut off the power supply 2 to prevent the fault from expanding and ensure the safety of the electric heating device 1. Since each heating element 20 has an independent control circuit, even if a certain heating element 20 fails, it will not affect the normal work of other heating elements 20.

[0045] In some embodiments, in combination with FIGS. 1, 3 and 4, the electric heating device 1 further includes a power switch 40. One end of the power switch 40 is electrically connected to the power supply 2, and the other end is electrically connected to the plurality of power switches 30. The control output end of the controller 80 is in communication connection with the power switch 40.

[0046] In this embodiment, the power switch 40 is a main switch for the whole electric heating device 1, when it is closed, it allows the current to flow from the power supply 2 to each power supply switch 30, and then provides power for the heating element 20. The controller 80 controls the on-off state of the power switch 40 and the power supply switch 30 by sending control signals, so as to realize accurate control of the single heating element 20 and the whole electric heating device 1. In this embodiment, by setting the power switch 40 as the main switch, an additional safety barrier is provided for the whole electric heating device 1. In an emergency, the controller 80 can quickly cut off the power switch 40, so as to immediately stop the work of all heating elements 20, prevent the fault from expanding, and protect the safety of the electric heating device 1.

[0047] Optionally, the power switch 40 includes an AC contactor. One end of the AC contactor is electrically connected with the power supply 2, and the other end is electrically connected with the plurality of power supply switches 30. The control output end of the controller 80 is in communication connection with the AC contactor. In this embodiment, the AC contactor is used as the power switch 40, so as to utilize the characteristics of the AC contactor, and improve the reliability and safety of the heating control of the electric heating device 1.

[0048] In some embodiments, as shown in FIG. 3 and FIG. 4, the power supply switch 30 and the power switch 40 are both AC contactors. For the convenience of understanding this embodiment, the AC contactor corresponding to the power supply switch 30 is named as a branch AC contactor, and the AC contactor corresponding to the power switch 40 is named as a total AC contactor. Then in this embodiment, one end of the total AC contactor is electrically connected with the power supply 2, and the other end is electrically connected with the plurality of branch AC contactors. The end of the branch AC contactor away from the total AC contactor is electrically connected with the power supply end of the heating element 20, and the plurality of branch AC contactors are one-to-one corresponding to the plurality of heating elements 20. The control output end of the controller 80 is in communication connection with the total AC contactor and the plurality of AC contactors, so as to control the conduction or disconnection of each AC contactor according to the received temperature information.

[0049] Optionally, the power supply 2 comprises a three-phase power supply or a single-phase power supply. The three-phase power supply is composed of three alternating current potentials with the same frequency, equal amplitude and phase difference of 120 degrees. In practical applications, the three-phase power supply includes three phase lines (also known as live lines) and a zero line (or neutral line). The three-phase power supply has obvious advantages in power generation, power transmission and distribution, and conversion of electrical energy into mechanical energy. The use of a three-phase power supply can take advantage of the three-phase power supply to improve power supply efficiency and stability. The phase difference of the three-phase power supply can offset the fluctuations of current and voltage, reducing line loss and electromagnetic interference in the electric heating device 1. The single-phase power supply refers to an alternating current power supply with only one voltage waveform in the power system. In practical applications, the single-phase power supply is composed of any one phase line (live line) and zero line of the three-phase four-wire alternating current, with a voltage of 220V. The single-phase power supply has the advantages of simple structure, easy installation, stable operation and relatively low cost.

[0050] Optionally, as shown in FIGS. 1 and 2, the electric heating device 1 further comprises a temperature controller 60. The temperature sensing probe 602 of the temperature controller 60 is located at the water outlet end 104 in the heating cavity 102 and is arranged to extend from one side wall of the heating cavity 102 to the opposite side wall. The control output end of the temperature controller 60 is in communication connection with the power supply end of the plurality of heating elements 20, and the temperature controller 60 is in communication connection with the controller 80.

[0051] In this embodiment, the temperature sensing probe 602 of the temperature controller 60 is arranged at the water outlet end 104 of the heating cavity 102 to detect the temperature of the water outlet end 104 of the heating cavity 102 for overheat protection. When the temperature sensing probe 602 of the temperature controller 60 detects that the temperature exceeds the preset temperature safety threshold, the power supply end of the plurality of heating elements 20 is disconnected to turn off all the heating elements 20, thereby avoiding excessive heating and potential safety hazards. At the same time, by monitoring the temperature of the water outlet end 104 in real time through the temperature sensing probe 602 and controlling the on-off of the power supply end of the plurality of heating elements 20, it can be ensured that the outlet water temperature of the electric heating device 1 after heating is always within a suitable range or a desired range, thereby improving the use comfort of the electric heating device 1.

[0052] In addition, the temperature sensing probe 602 of the temperature controller 60 is arranged to extend from one side wall of the heating cavity 102 to the opposite side wall of the shell 10 to increase the contact area between the temperature sensing probe 602 and the surrounding environment, thereby improving the temperature detection sensitivity of the temperature controller 60 and further improving the use safety and use comfort of the electric heating device 1.

[0053] In this application, the temperature safety threshold is a specific temperature value. When the temperature exceeds this value, it can be considered that potential safety hazards may occur, such as scalding users, causing fires, and burning adjacent devices.

[0054] Optionally, in combination with FIG. 1 and FIG. 2, the temperature controller 60 is communicatively connected with the controller 80, and cooperates with the controller 80 to realize the overheat protection. For example, the controller 80 generates a temperature safety threshold, and transmits the temperature safety threshold to the temperature controller 60. When the temperature of the water outlet 104 exceeds the temperature safety threshold, the temperature controller 60 controls the power supply end of the plurality of heating elements 20 to be disconnected, so as to turn off all the heating elements 20, and realize the overheat protection.

[0055] In some embodiments, in combination with FIG. 1, FIG. 3 and FIG. 4, the control output end of the temperature controller 60 is communicatively connected with the power switch 40.

[0056] Optionally, in combination with FIG. 2, the electric heating device 1 further comprises a water level detection device 70. The water level detection device 70 is arranged in the shell 10, and is configured to detect the water level in the heating cavity 102.

[0057] In this embodiment, the water level detection device 70 is configured to detect the water level in the heating cavity 102, and determine whether the water in the heating cavity 102 fills the entire heating cavity 102. When the water does not fill the entire heating cavity 102, it is determined that the electric heating device 1 has a dry burning phenomenon in the partial (water outlet 104 of the electric heating device 1). When the temperature of the water outlet 104 exceeds the temperature safety threshold, it is determined that the water outlet 104 of the electric heating device 1 has an overheat dry burning phenomenon, and there is a safety hazard. When the water level detection device 70 detects that the water in the heating cavity 102 does not fill the entire heating cavity 102, and the temperature of the water outlet 104 of the heating cavity 102 exceeds the temperature safety threshold, it is determined that the current electric heating process of the electric heating device 1 has a safety hazard, which improves the safety detection accuracy of the electric heating device 1, and further improves the use safety of the electric heating device 1.

[0058] It should be noted that the specific value of the temperature safety threshold needs to be set according to the actual use scene and the electric heating device 1, and the present application does not limit it. For example, when the temperature safety threshold is used for outlet water temperature detection, and the electric heating device 1 is a water heater, the value of the temperature safety threshold is 50℃, 55℃ or 60℃, so as to avoid the outlet water temperature being too high to scald the user. When the temperature safety threshold is used for outlet water temperature detection, and the electric heating device 1 is a water dispenser, the value of the temperature safety threshold is 100℃, 102℃ or 105℃, so as to avoid the outlet water temperature being too low, and the heating being insufficient, which brings health hazards to the user. When the temperature safety threshold is used for detecting the dry burning phenomenon, the value of the temperature safety threshold is 70℃, 80℃ or 90℃, so as to avoid excessive dry burning, and cause fire or device damage.

[0059] In some embodiments, as shown in FIG. 2, the water level detection device 70 comprises a water level sensor 702 and / or a flow meter 704. The water level sensor 702 and / or the flow meter 704 are arranged to detect the water level inside the heating cavity 102, to determine whether the water in the heating cavity 102 fills the entire heating cavity 102, and to determine whether the electric heating device 1 has a local dry burning phenomenon.

[0060] Optionally, as shown in FIG. 2, the water level detection device 70 comprises the water level sensor 702. The water level sensor 702 is arranged in the housing 10 and located in the heating cavity 102.

[0061] In this embodiment, the water level sensor 702 is arranged in the heating cavity 102 to detect the water level inside the heating cavity 102, to determine whether the water in the heating cavity 102 fills the entire heating cavity 102, and to determine whether the electric heating device 1 has a local dry burning phenomenon. Specifically, when the water in the heating cavity 102 fills the entire heating cavity 102, it is determined that the electric heating device 1 does not have a dry burning phenomenon. When the water in the heating cavity 102 does not fill the entire heating cavity 102, it is determined that the electric heating device 1 has a local dry burning phenomenon.

[0062] Optionally, as shown in FIG. 2, the water level sensor 702 is arranged on the side wall of the heating cavity 102 and extends from the water inlet end 106 to the water outlet end 104 of the heating cavity 102. The water level sensor 702 is arranged from the water inlet end 106 to the water outlet end 104 of the heating cavity 102 to improve the sensitivity and accuracy of water level detection, thereby further improving the sensitivity and accuracy of safety detection of the electric heating device 1.

[0063] It should be noted that the arrangement of the water level sensor 702 in the heating cavity 102 varies depending on the type of the water level sensor 702. The specific arrangement of the water level sensor 702 in the heating cavity 102 is determined by the actual type of the water level sensor 702, which is not limited in the present application. For example, the water level sensor 702 can be a float type water level sensor 702, a capacitive type water level sensor 702, an ultrasonic type water level sensor 702, or a pressure type water level sensor 702.

[0064] Optionally, as shown in FIG. 2, the water level detection device 70 comprises the flow meter 704. The flow meter 704 is arranged at the water inlet end 106 of the housing 10.

[0065] In this embodiment, the flow meter 704 is installed at the water inlet end 106 of the shell 10 to monitor the water flow entering the heating cavity 102 in real time, so as to determine the water level change in the heating cavity 102 according to the water capacity of the heating cavity 102 (the volume of water that can be contained in the heating cavity 102), and determine whether the water in the heating cavity 102 fills the entire heating cavity 102, so as to determine whether the dry burning phenomenon exists in the electric heating device 1.

[0066] In practical application, the flow meter 704 includes an electromagnetic flow meter 704, an ultrasonic flow meter 704 or a vortex flow meter 704.

[0067] Optionally, as shown in FIG. 2, the water level detection device 70 includes the water level sensor 702 and the flow meter 704. The water level sensor 702 is arranged in the shell 10 and located in the heating cavity 102. The flow meter 704 is arranged at the water inlet end 106 of the shell 10.

[0068] In this embodiment, the water level sensor 702 and the flow meter 704 are installed at the same time, so as to comprehensively monitor the water level and the water flow state in the heating cavity 102, improve the sensitivity and accuracy of the water level detection in the heating cavity 102, and further improve the sensitivity and accuracy of the safety detection of the electric heating device 1.

[0069] Specifically, the average value of the water level calculated by the detection of the water level sensor 702 and the flow meter 704 can be taken as the final water level information, so as to improve the sensitivity and accuracy of the water level detection in the heating cavity 102.

[0070] Optionally, as shown in FIG. 1, the number of the temperature sensors 50 is multiple. The multiple temperature sensors 50 are in communication connection with the controller 80. The multiple temperature sensors 50 can be arranged at the water outlet end 104 and / or the water inlet end 106 of the shell 10 according to the requirement, so as to acquire the collected temperature information and transmit the temperature information to the controller 80.

[0071] In practical application, the controller 80 includes a computer control board or a microcontroller.

[0072] Optionally, as shown in FIG. 5, the controller 80 includes a processor 800 and a memory 801. Optionally, the controller 80 can further include a communication interface 802 and a bus 803. The processor 800, the communication interface 802 and the memory 801 can complete the communication among each other through the bus 803. The communication interface 802 can be used for information transmission. The processor 800 can call the logical instructions in the memory 801 to execute the control method of the electric heating device in the following embodiments.

[0073] In addition, the logic instructions in the memory 801 described above can be implemented in the form of a software function unit and sold or used as an independent product, which can be stored in a computer readable storage medium.

[0074] The memory 801 as a computer readable storage medium can be used to store software programs, computer executable programs, such as program instructions / modules corresponding to the method in the embodiments of the present disclosure. The processor 800 executes the function application and data processing by running the program instructions / modules stored in the memory 801, that is, implements the control method of the electric heating device in the following embodiments.

[0075] The memory 801 can include a program storage area and a data storage area, wherein the program storage area can store an operating system and application programs required by at least one function; the data storage area can store data created according to the use of the terminal device, etc. In addition, the memory 801 can include a high-speed random access memory, and can also include a non-volatile memory.

[0076] In combination with the electric heating device shown in FIGS. 1 to 5, the embodiment of the present disclosure provides a control method of an electric heating device, as shown in FIG. 6, the control method comprises:

[0077] S601, obtaining the outlet water temperature of the electric heating device and the heating time length of the heating element.

[0078] S602, obtaining the first temperature difference between the target temperature and the outlet water temperature.

[0079] S603, determining the target opening number of the heating element according to the first temperature difference and the heating time length, and controlling the corresponding number of heating elements to open.

[0080] S604, when the first temperature difference is less than or equal to the first temperature difference threshold, controlling all the heating elements to close.

[0081] In this embodiment, the outlet water temperature of the electric heating device refers to the temperature of the water flowing out after being heated by the electric heating device. The outlet water temperature can be collected and obtained by a temperature sensor arranged at the outlet end of the shell, or collected and obtained by a temperature sensing probe of a temperature controller, or obtained by calculating the average value of the temperature values collected by the temperature sensor arranged at the outlet end of the shell and the temperature sensing probe.

[0082] The heating time length of the heating element refers to the time length of the heating work performed after the heating element is started. The heating time length of the heating element can be monitored and obtained by a controller in communication connection with the power supply end of the heating element.

[0083] The target temperature refers to the temperature of the water set by the user according to the actual demand. The first temperature difference ΔT1 between the outlet water temperature and the target temperature is obtained in the following manner: ΔT1=T t -To wherein, T t represents the target temperature, T o represents the outlet water temperature of the electric heating device, in units of degrees Celsius (℃).

[0084] The first temperature difference threshold is a temperature difference value that is specifically set by the technician according to the actual electric heating device. The first temperature difference threshold is used to determine the size of the first temperature difference. For example, the specific value of the first temperature difference threshold is 4℃, 5℃, or 6℃.

[0085] The control method of the electric heating device provided by the embodiments of the present disclosure comprehensively considers the first temperature difference between the target temperature and the outlet water temperature and the heating time of the heating element to determine the target number of openings of the heating element, thereby achieving more precise temperature regulation to quickly and smoothly reach the target temperature. Compared with synchronously starting and stopping all heating elements in the related art, by dynamically adjusting the target number of openings of the heating element, the adjustment of the real-time heating power is realized, which can avoid excessive heating or energy waste, reduce the fluctuation range of the outlet water temperature, and improve the stability and reliability of the outlet water temperature of the electric heating device. In addition, when the first temperature difference is less than or equal to the first temperature difference threshold, it indicates that the first temperature difference is small, and the outlet water temperature is already very close to the target temperature. At this time, all the heating elements are controlled to be closed, and the residual heat of the heating elements is used to heat the water body, further avoiding excessive heating or energy waste, and improving the reliability of the electric heating device.

[0086] Optionally, determining the target number of openings of the heating element according to the first temperature difference and the heating time includes: comparing the first temperature difference with a plurality of temperature difference thresholds, and determining an initial number of openings of the heating element according to the comparison result; when the heating time is less than or equal to a first time threshold, taking the initial number of openings as the target number of openings; when the heating time is greater than the first time threshold, correcting the initial number of openings; and taking the corrected initial number of openings as the target number of openings.

[0087] In this embodiment, a plurality of temperature difference thresholds are pre-set, and the temperature difference threshold is a temperature difference value that is specifically set by the technician according to the actual electric heating device. The temperature difference threshold is used to determine the size of the first temperature difference. The plurality of temperature difference thresholds include the first temperature difference threshold described in the above embodiments. Each temperature difference threshold corresponds to the opening state of one or more heating elements to form a hierarchical control strategy. By comparing the first temperature difference with a plurality of temperature difference thresholds, and according to the comparison result, the initial number of openings of a heating element is preliminarily determined as an initial number of openings. The initial number of openings is a rapid response to the temperature deviation (i.e., the first temperature difference) between the target temperature and the current outlet water temperature, aiming to make the outlet water temperature quickly approach the target temperature.

[0088] For example, the number of temperature difference thresholds is 6, and the first temperature difference threshold, the second temperature difference threshold, the third temperature difference threshold, the fourth temperature difference threshold, the fifth temperature difference threshold and the sixth temperature difference threshold are arranged in ascending order. The number of heating elements is 6. When the first temperature difference is greater than the sixth temperature difference threshold, the initial opening number of the heating elements is 6; when the sixth temperature difference threshold is greater than the first temperature difference and the first temperature difference is greater than the fifth temperature difference threshold, the initial opening number of the heating elements is 5; when the fifth temperature difference threshold is greater than the first temperature difference and the first temperature difference is greater than the fourth temperature difference threshold, the initial opening number of the heating elements is 4; when the fourth temperature difference threshold is greater than the first temperature difference and the first temperature difference is greater than the third temperature difference threshold, the initial opening number of the heating elements is 3; when the third temperature difference threshold is greater than the first temperature difference and the first temperature difference is greater than the second temperature difference threshold, the initial opening number of the heating elements is 2; and when the second temperature difference threshold is greater than the first temperature difference and the first temperature difference is greater than the first temperature difference threshold, the initial opening number of the heating elements is 1.

[0089] For example, the specific value of the first temperature difference threshold is 4℃, 5℃ or 6℃; the specific value of the second temperature difference threshold is 8℃, 9℃ or 10℃; the specific value of the third temperature difference threshold is 13℃, 14℃ or 15℃; the specific value of the fourth temperature difference threshold is 19℃, 20℃ or 21℃; the specific value of the fifth temperature difference threshold is 25℃, 26℃ or 27℃; and the specific value of the sixth temperature difference threshold is 35℃, 36℃ or 37℃.

[0090] In this embodiment, a first time threshold is set in advance, and the first time threshold is used to distinguish the heating stages of the current heating process, such as the early stage and the late stage. When the heating time is less than or equal to the first time threshold, it indicates that the electric heating device is in the early stage, and at this time the initial opening number is directly used as the target opening number to maintain the current heating state. When the heating time is greater than the first time threshold, it indicates that the electric heating device is in the late stage, and then the initial opening number is corrected according to the actual situation to keep the outlet water temperature stable, reduce the outlet water temperature fluctuation, and further optimize the energy utilization rate.

[0091] Optionally, the first time threshold t1 is determined in the following manner: t1=k×(T o -T i ); wherein T o represents the outlet water temperature of the electric heating device, T i represents the inlet water temperature of the electric heating device, and k represents an adjustment parameter, k>0.

[0092] In this embodiment, the inlet water temperature of the electric heating device refers to the temperature of the water flowing into the electric heating device and not heated by the electric heating device, and the unit is degree Celsius (℃). The inlet water temperature can be collected by a temperature sensor arranged at the inlet end of the shell. The adjustment parameter k refers to the temperature difference between the outlet water temperature and the inlet water temperature (T o -Ti ) and a parameter of the first time length threshold t1, unit: minute / degree Celsius (min / ℃). The adjustment parameter k is adjusted to be greater than 0, that is, the first time length threshold t1 is proportional to the temperature difference (T o -T i ) is proportional. The specific value of the adjustment parameter k needs to be set by the technician according to the actual electric heating device, which is not limited in the present application. For example, the specific value of the adjustment parameter k is 0.1 min / ℃, 0.15 min / ℃ or 0.2 min / ℃.

[0093] In this embodiment, by dynamically adjusting the first time length threshold t1, the current heating state and trend of the electric heating device are more accurately reflected, and the heating power control accuracy of the electric heating device is further improved, and the temperature control accuracy of the electric heating device is improved.

[0094] Optionally, the initial opening number is corrected, including: correcting the initial opening number according to a first correction value.

[0095] In this embodiment, the first correction value is set to correct the initial opening number, and the first correction value is a natural number greater than 0. The specific value of the first correction value needs to be set by the technician according to the actual electric heating device, which is not limited in the present application. When the comparison result of the first temperature difference and the plurality of temperature difference thresholds is unchanged and the heating time is greater than the first time length threshold, the initial opening number is corrected according to the first correction value to improve the heating power of the electric heating device, so that the outlet water temperature can approach the target temperature as soon as possible. For example, the value of the first correction value is 1, 2 or 3.

[0096] Optionally, the initial opening number is corrected, including: obtaining a temperature difference change rate of the first temperature difference; determining a second correction value of the initial opening number according to the temperature difference change rate, and correcting the initial opening number according to the second correction value.

[0097] The temperature difference change rate of the first temperature difference reflects the change speed of the first temperature difference with time, that is, the speed of the outlet water temperature change. In this embodiment, an association between the temperature difference change rate and the second correction value is set in advance. For example, the temperature difference change rate is inversely proportional to the second correction value. It is intended to slow down or speed up the adjustment process by reducing or increasing the second correction value as the temperature difference change rate, so as to avoid excessive adjustment of the number of heating elements or to reach the target temperature as soon as possible.

[0098] Optionally, the second correction value of the initial opening quantity is determined according to the temperature difference change rate, comprising: comparing the temperature difference change rate with a change rate threshold; when the temperature difference change rate is equal to the change rate threshold, determining the second correction value of the initial opening quantity as 0; when the temperature difference change rate is greater than the change rate threshold, determining the second correction value of the initial opening quantity as a negative number; and when the temperature difference change rate is less than the change rate threshold, determining the second correction value of the initial opening quantity as a positive number.

[0099] In this embodiment, a change rate threshold is preset for evaluating the speed of the temperature difference change rate. The specific value of the change rate threshold needs to be preset by a technician according to the actual electric heating device, which is not limited in this application.

[0100] When the temperature difference change rate is equal to the change rate threshold, it indicates that the current temperature change speed is moderate, and the initial opening quantity does not need to be adjusted, and the second correction value is determined as 0, that is, the initial opening quantity is kept unchanged. When the temperature difference change rate is greater than the change rate threshold, it indicates that the current temperature change speed is fast, which is easy to cause the outlet water temperature to overshoot and produce a large range of temperature fluctuations. Therefore, the second correction value is determined as a negative number, that is, the opening quantity of the heating element is reduced to stabilize the temperature rising speed. When the temperature difference change rate is less than the change rate threshold, it indicates that the current temperature change speed is slow, which is easy to fail to reach the target temperature in time. Therefore, the second correction value is determined as a positive number, that is, the opening quantity of the heating element is increased to improve the heating efficiency.

[0101] In this embodiment, by comparing the temperature difference change rate with the change rate threshold and determining the positive or negative or size of the second correction value, the electric heating device can accurately respond to the trend and speed requirement of temperature change, reduce temperature fluctuations and overshoot phenomenon, and further improve the stability and precision of temperature control.

[0102] For example, the specific value of the change rate threshold is 10℃ / min, 15℃ / min or 20℃ / min; when the temperature difference change rate is greater than the change rate threshold, the specific value of the second correction value is -1, -2 or -3; and when the temperature difference change rate is less than the change rate threshold, the specific value of the second correction value is 1, 2 or 3.

[0103] Optionally, after the corrected initial opening quantity is taken as the target opening quantity, the control method further comprises: resetting the heating time length and re-determining the first time threshold.

[0104] In this embodiment, by resetting the heating time length and re-determining the first time threshold, the potential influence of the previous heating time length and the first time threshold on the control decision is eliminated, so that the electric heating device can make decisions based on the latest first time threshold and target opening quantity, further improve the precision and stability of temperature control, and reduce temperature fluctuations and overshoot phenomenon.

[0105] With reference to FIG. 7, the disclosure provides another control method of the electric heating device, comprising:

[0106] S701, obtaining the outlet water temperature of the electric heating device and the heating time length of the heating element.

[0107] S702, obtaining the first temperature difference between the target temperature and the outlet water temperature.

[0108] S703, determining the target number of the heating element to be turned on according to the first temperature difference and the heating time length, and controlling the corresponding number of heating elements to be turned on.

[0109] S704, when the first temperature difference is less than or equal to the first temperature difference threshold, controlling all the heating elements to be turned off.

[0110] S705, comparing the first temperature difference with the off temperature difference threshold.

[0111] S706, when the first temperature difference is less than or equal to the off temperature difference threshold, controlling all the heating elements to be turned off.

[0112] S707, when the first temperature difference is greater than the off temperature difference threshold, obtaining the inlet water temperature of the electric heating device and the running time length.

[0113] S708, when the outlet water temperature is less than or equal to the inlet water temperature and the outlet water temperature is less than the target temperature, or the outlet water temperature is greater than the inlet water temperature, the running time length is greater than the second time length threshold, and the outlet water temperature is less than the target temperature, controlling one heating element to be turned on.

[0114] S709, when the outlet water temperature is greater than or equal to the target temperature, controlling all the heating elements to be turned off.

[0115] The off temperature difference threshold is less than the first temperature difference threshold. The off temperature difference threshold is a temperature difference value set by the technician according to the actual electric heating device. The off temperature difference threshold is used to determine the size of the first temperature difference. For example, the specific value of the off temperature difference threshold is 1℃, 2℃ or 3℃.

[0116] The running time length of the electric heating device refers to the time length of the electric heating device after starting to heat the water body. The running time length of the electric heating device can be monitored and obtained by the controller in communication connection with the power supply end of the plurality of heating elements.

[0117] The second time length threshold is a time length value set by the technician according to the actual electric heating device. The second time length threshold is used to determine the length of time for the electric heating device to heat the water body after starting.

[0118] The control method of the electric heating device provided by the embodiments of the present disclosure can control all the heating elements to be closed when the first temperature difference is less than or equal to the first temperature difference threshold, further monitor the outlet water temperature of the electric heating device during the process of heating by using the residual heat of the heating elements, reduce the fluctuation range of the outlet water temperature, and ensure the stability of the outlet water temperature.

[0119] Specifically, by comparing the first temperature difference with the closing temperature difference threshold, since the closing temperature difference threshold is less than the first temperature difference threshold, when the first temperature difference is less than or equal to the closing temperature difference threshold, it indicates that the first temperature difference continues to decrease and reaches a smaller temperature difference value, at this time, the outlet water temperature is closer to the target temperature, and then all the heating elements are controlled to be closed to maintain the closed state of all the heating elements and ensure the stability of the outlet water temperature of the electric heating device.

[0120] When the first temperature difference is greater than the closing temperature difference threshold, it indicates that the first temperature difference does not reach the expected smaller temperature difference value, and then the inlet water temperature and the running time of the electric heating device are introduced to further regulate the heating power of the electric heating device in combination with the running state of the electric heating device, so that the outlet water temperature is closer to the target temperature and the fluctuation range of the outlet water temperature is reduced.

[0121] Specifically, when the outlet water temperature is less than or equal to the inlet water temperature and the outlet water temperature is less than the target temperature, it indicates that the outlet water temperature decreases, and the residual heat of the heating elements can no longer heat the water body, but the outlet water temperature cannot meet the user's demand (the target temperature), and therefore one heating element is controlled to be turned on to continue heating the water body by restarting one heating element while avoiding that the heating power is too large to cause the outlet water temperature to fluctuate greatly. When the running time is greater than the second time threshold and the outlet water temperature is greater than the inlet water temperature and the outlet water temperature is less than the target temperature, it indicates that the outlet water temperature has increased, but still cannot meet the user's demand, and the running time of the electric heating device is long, and therefore one heating element is restarted to heat the water body, which improves the heating efficiency of the electric heating device while avoiding that the heating power is too large to cause the outlet water temperature to fluctuate greatly.

[0122] Optionally, the control method further includes: when the outlet water temperature is greater than the inlet water temperature and the running time is less than or equal to the second time threshold, the outlet water temperature is reacquired and compared with the inlet water temperature.

[0123] In this embodiment, when the outlet water temperature is greater than the inlet water temperature, it indicates that the residual heat of the heating elements continues to heat the water body, and therefore the outlet water temperature is reacquired and compared with the inlet water temperature to continuously monitor the heating state of the residual heat of the heating elements on the water body.

[0124] In combination with FIG. 8, another control method of an electric heating device is provided by the embodiments of the present disclosure, which includes:

[0125] S801, acquire the outlet temperature of the shell.

[0126] S802, in the case that the outlet temperature is greater than the temperature safety threshold, control all the heating elements to be closed.

[0127] S803, in the case that the outlet temperature is less than or equal to the temperature safety threshold, acquire the outlet temperature of the electric heating device and the heating time of the heating elements.

[0128] S804, according to the first temperature difference and the heating time, determine the target number of the heating elements to be turned on and control the corresponding number of the heating elements to be turned on.

[0129] S805, in the case that the first temperature difference is less than or equal to the first temperature difference threshold, control all the heating elements to be closed.

[0130] In this embodiment, the outlet temperature of the shell refers to the temperature of the shell at the outlet of the electric heating device when the water body does not fill the entire heating cavity. The outlet temperature can be acquired by a temperature sensor arranged at the outlet of the shell, or acquired by a temperature sensing probe of a temperature controller, or acquired by calculating the average of the temperature values acquired by the temperature sensor arranged at the outlet of the shell and the temperature sensing probe.

[0131] The control method of the electric heating device provided by the embodiment of the present disclosure can avoid the safety hazard of the electric heating device due to excessive dry burning by monitoring the outlet temperature and comparing the outlet temperature with the temperature safety threshold when the water body does not fill the entire heating cavity. Specifically, in the case that the outlet temperature is greater than the temperature safety threshold, all the heating elements are controlled to be closed to stop heating, and when the water body fills the entire heating cavity or the outlet temperature drops below the temperature safety threshold, the heating elements are started to heat the water body, thereby avoiding excessive dry burning and improving the use safety of the electric heating device. In the case that the outlet temperature is less than or equal to the temperature safety threshold, it indicates that the electric heating device does not occur local dry burning, or the temperature generated by the dry burning position is low, which will not cause safety hazard, and at this time, the outlet temperature of the electric heating device and the heating time of the heating elements are acquired to continue the heating process.

[0132] The embodiment of the present disclosure provides a computer-readable storage medium, which stores computer executable instructions, and the computer executable instructions are configured to execute the control method of the electric heating device.

[0133] The embodiment of the present disclosure provides a computer-readable non-transitory storage medium, which stores program instructions, and the program instructions execute the following steps when running:

[0134] acquire a water outlet temperature of the electric heating device and a heating duration of the heating element;

[0135] acquire a first temperature difference between the target temperature and the water outlet temperature;

[0136] determine a target number of the heating element to be turned on according to the first temperature difference and the heating duration, and control the corresponding number of the heating element to be turned on;

[0137] when the first temperature difference is less than or equal to a first temperature difference threshold, control all the heating element to be turned off.

[0138] The embodiments of the present disclosure provide a computer program, which, when executed by a computer, causes the computer to implement the control method of the electric heating device.

[0139] The embodiments of the present disclosure provide a computer program product, which comprises computer instructions stored on a computer readable storage medium, and when the program instructions are executed by a computer, the computer implements the control method of the electric heating device.

[0140] The technical solutions of the embodiments of the present disclosure can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes one or more instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiments of the present disclosure. The aforementioned storage medium can be a non-transitory storage medium, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0141] The above description and drawings are illustrative of embodiments of the present disclosure and are not intended to be limiting. Other embodiments can include structural, logical, electrical, procedural, and other changes. The embodiments are illustrative only. Individual components and functions are optional, and the order of operations can vary. Portions and features of some embodiments can be included in, or substituted for, those of other embodiments. Also, the terminology used herein is for the purpose of describing embodiments only and is not intended to be limiting. As used in the description of the embodiments and the claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and / or" as used herein refers to any and all possible combinations of one or more of the associated listed items. In addition, the term "comprises" and variations thereof, as used in the present application, are intended to mean that the process, method, or apparatus includes the recited features, integers, steps, operations, elements, and / or components, but not to the exclusion of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Unless otherwise defined, an element specified by the phrase "comprising a..." does not exclude the presence of additional same elements in the process, method, or apparatus including the recited element. In the present document, each embodiment can focus on the differences from other embodiments, and the same or similar parts between embodiments can be referred to each other. For the method, product, etc. disclosed by the embodiments, if it corresponds to the method part of the embodiments, the relevant part can be referred to the description of the method part.

[0142] Embodiments of the present disclosure are not limited to the structures described above and shown in the drawings, and can be variously modified and changed without departing from the scope thereof. The scope of the present disclosure is only limited by the appended claims.

[0143] Those skilled in the art can understand that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of the embodiments of the present disclosure. The skilled person can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0144] In the embodiments disclosed herein, the disclosed methods, products (including but not limited to apparatuses, devices, etc.), can be implemented in other manners. For example, the described apparatus embodiments can be implemented only in a form of a logical function, and can be implemented by using a manner such as software (for example, application program) or the like. In some embodiments, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling or direct coupling or indirect coupling between different units, or the coupling or direct coupling or indirect coupling between the displayed or discussed communication connections can be in a form of electrical, mechanical or other forms.

[0145] The flowcharts and block diagrams in the drawings show the possible implementation architectures, functions and operations of the system, method and computer program product according to the embodiments of the present disclosure. In this regard, each block in the flowcharts or block diagrams can represent a module, a program segment or a part of code containing one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions noted in the blocks can occur in an order different from that noted in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the drawings, the operations or steps corresponding to different blocks can also occur in an order different from that disclosed in the descriptions, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the functions involved. Each block in the block diagrams and / or flowcharts, and the combination of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. An electric heating device, comprising: a housing comprising a mounting cavity; a plurality of heating elements arranged in the heating cavity; a temperature sensor arranged at a water outlet end of the housing; a controller, an information input end of the controller being communicatively connected with the temperature sensor to receive temperature information output by the temperature sensor, and a control output end of the controller being communicatively connected with power supply ends of the plurality of heating elements to control the power supply ends of the plurality of heating elements to be turned on or turned off according to the received temperature information.

2. The electric heating device according to claim 1, further comprising: a plurality of power supply switches, opposite ends of each of the plurality of power supply switches being electrically connected with a power supply and a power supply end of a corresponding one of the plurality of heating elements, respectively, the plurality of power supply switches being arranged in one-to-one correspondence with the plurality of heating elements; wherein the control output end of the controller being communicatively connected with the plurality of power supply switches to control the plurality of power supply switches to be turned on or turned off according to the received temperature information.

3. The electric heating device according to claim 1 or 2, further comprising: a temperature controller, a temperature sensing probe of the temperature controller being arranged at the water outlet end in the heating cavity and extending from a side wall of the heating cavity to an opposite side wall, a control output end of the temperature controller being communicatively connected with the power supply ends of the plurality of heating elements, and the temperature controller being communicatively connected with the controller.

4. The electric heating device according to any one of claims 2 or 3, further comprising: a power supply switch, one end of the power supply switch being electrically connected with the power supply, and the other end of the power supply switch being electrically connected with the plurality of power supply switches, and the control output end of the controller being communicatively connected with the power supply switch.

5. The electric heating device according to claim 4, wherein, the power supply switch comprising: an alternating current contactor, one end of the alternating current contactor being electrically connected with the power supply, and the other end of the alternating current contactor being electrically connected with the plurality of power supply switches, and the control output end of the controller being communicatively connected with the alternating current contactor.

6. An electric heating device according to any one of claims 2 to 5, wherein, the power supply comprising a three-phase power supply or a single-phase power supply.

7. The electric heating device according to any one of claims 1 to 6, further comprising: a water level detection device arranged in the housing and configured to detect a water level in the heating cavity.

8. The electric heating device according to claim 7, wherein the water level detection device comprising a water level sensor and / or a flow meter.

9. A control method for the electric heating device according to any one of claims 1 to 8, comprising: obtaining an outlet water temperature of the electric heating device and a heating duration of the heating elements; obtaining a first temperature difference between a target temperature and the outlet water temperature; determining a target number of the heating elements to be turned on according to the first temperature difference and the heating duration, and controlling the corresponding number of the heating elements to be turned on; controlling all the heating elements to be turned off when the first temperature difference is less than or equal to a first temperature difference threshold.

10. The control method according to claim 9, wherein determining the target number of the heating elements to be turned on according to the first temperature difference and the heating duration, comprising: comparing the first temperature difference with a plurality of temperature difference thresholds, and determining an initial number of the heating elements to be turned on according to a comparison result; when the heating duration is less than or equal to a first duration threshold, taking the initial number of the heating elements to be turned on as the target number of the heating elements to be turned on; when the heating duration is greater than the first duration threshold, modifying the initial number of the heating elements to be turned on, and taking the modified initial number of the heating elements to be turned on as the target number of the heating elements to be turned on.

11. The control method according to claim 10, wherein The first time length threshold t1 is determined in the following manner: t1 = k x (T o -T i ); where T o represents the outlet water temperature of the electric heating device, T i represents the inlet water temperature of the electric heating device, and k represents an adjustment parameter.

12. The control method according to claim 10 or 11, wherein modifying the initial number of the heating elements to be turned on, comprising: modifying the initial number of the heating elements to be turned on by a first modification value; or obtain a temperature difference change rate of the first temperature difference; determine a second correction value of the initial opening number according to the temperature difference change rate, and correct the initial opening number according to the second correction value.

13. The control method according to claim 12, wherein determining a second correction value of the initial opening number according to the temperature difference change rate, comprises: comparing the temperature difference change rate with a change rate threshold value; when the temperature difference change rate is equal to the change rate threshold value, determining that the second correction value of the initial opening number is 0; when the temperature difference change rate is greater than the change rate threshold value, determining that the second correction value of the initial opening number is a negative number; when the temperature difference change rate is less than the change rate threshold value, determining that the second correction value of the initial opening number is a positive number.

14. The method according to any one of claims 10 to 13, wherein, after taking the corrected initial opening number as the target opening number, further comprising: resetting the heating time length and re-determining the first time length threshold value.

15. The control method according to any one of claims 9 to 14, further comprising: comparing the first temperature difference with a shutdown temperature difference threshold value; controlling all the heating elements to be turned off when the first temperature difference is less than or equal to the shutdown temperature difference threshold value; wherein the shutdown temperature difference threshold value is less than the first temperature difference threshold value.

16. The control method according to claim 15, further comprising: when the first temperature difference is greater than the shutdown temperature difference threshold value, obtaining a water inlet temperature and a running time length of the electric heating device; controlling one heating element to be turned on when the water outlet temperature is less than or equal to the water inlet temperature and the water outlet temperature is less than the target temperature, or the water outlet temperature is greater than the water inlet temperature, the running time length is greater than a second time length threshold value and the water outlet temperature is less than the target temperature; controlling all the heating elements to be turned off when the water outlet temperature is greater than or equal to the target temperature.

17. The control method according to any one of claims 9 to 16, wherein before obtaining the water outlet temperature and the heating time length of the heating element, further comprising: obtaining a water outlet end temperature of the shell; controlling all the heating elements to be turned off when the water outlet end temperature is greater than a temperature safety threshold value; obtaining the water outlet temperature and the heating time length of the heating element when the water outlet end temperature is less than or equal to the temperature safety threshold value.

18. A computer readable non-transitory storage medium storing program instructions, which when executed, implement the following steps of program instructions: obtaining a water outlet temperature and a heating time length of a heating element of an electric heating device; obtaining a first temperature difference between a target temperature and the water outlet temperature; determining a target opening number of the heating element according to the first temperature difference and the heating time length, and controlling a corresponding number of heating elements to be turned on; controlling all the heating elements to be turned off when the first temperature difference is less than or equal to a first temperature difference threshold value.

19. A computer program, which when executed by a computer, causes the computer to implement the control method of the electric heating device according to any one of claims 9 to 17.

20. A computer program product comprising computer instructions stored on a computer readable storage medium, which when executed by a computer, causes the computer to implement the control method of the electric heating device according to any one of claims 9 to 17.

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