A method and system for safety access control and reachability domain control of an electric water heater for mothers and infants.

Abstract

This invention discloses a safety access and reachability domain control method and system for electric water heaters designed for use by mothers and infants. Relating to the field of household appliance technology, this invention addresses the shortcomings of existing electric water heaters that commonly employ reactive control in mother-and-infant scenarios. These methods fail to fundamentally solve the temperature surge problem caused by the thermal inertia of the heating unit, and safety constraints are easily overridden by user settings, posing a high risk of scalding. This invention detects whether the water heater is in mother-and-infant use mode, collects operating parameters before heating starts, constructs a mother-and-infant safety reachability domain, performs a pre-heating safety access judgment, limits the power within the reachability domain during heating operation, and applies system-level safety constraints. In abnormal operating conditions, it switches to the lowest safe power operation. This invention can prevent temperature surges from the source, improve the inherent safety of mother-and-infant water use, reduce secondary risks from abnormal operating conditions, and facilitate engineering-scale application.

Description

Technical Field

[0001] This invention relates to the field of household appliance technology, specifically to a safety access and reachability control method and system for an electric water heater for mothers and infants. Background Technology

[0002] Electric water heaters (especially instantaneous electric water heaters) are widely used in mother and baby water use scenarios due to their instant hot water feature. When preparing bath water or formula for infants, the safety and stability of the water temperature are directly related to the user's personal safety. However, due to the thermal inertia of the heating unit in instantaneous electric water heaters and the lag in power regulation, temperature overshoot or fluctuations are prone to occur under low water volume conditions, posing a risk of scalding to the delicate skin of infants.

[0003] To ensure the safety of water used by mothers and infants, relevant technical solutions have been disclosed. For example, invention patent CN111174440B discloses a control method, a water heater system, and a computer-readable storage medium. This solution sets child bathing operation information in the water heater. This information includes multiple bathing stages set sequentially within a preset time period and the corresponding outlet water temperature range for each bathing stage. After receiving a control command to operate according to the child bathing operation information, the control method obtains the outlet water temperature range corresponding to each bathing stage based on the operation information and controls the water heater to output water at that outlet temperature. The shortcomings of this solution are: its control method is based on a preset time period and sequential stages, which is an open-loop timed temperature limiting method. It fails to dynamically adjust the heating power according to the real-time water flow and inlet water temperature. When the water flow fluctuates, the actual outlet water temperature may deviate from the preset range.

[0004] For example, invention patent CN101446446A discloses a method for constructing an instant electric water heater with anti-scalding function and the water heater itself. This solution involves installing a temperature probe connected to a microcomputer on the outlet pipe of the heating element, and installing a solenoid valve controlled by the microcomputer between the inlet and outlet pipes. When the water temperature inside the heating element rises rapidly, the microcomputer opens the solenoid valve, allowing a large amount of cold water to enter and mix with the hot water in the outlet pipe before flowing out. The drawback of this solution is that its anti-scalding mechanism is a passive mixing and cooling method that intervenes only after the temperature has risen to a dangerous level. It cannot actively prevent temperature shocks from the heating control level, and the introduction of the solenoid valve and bypass pipe increases the system complexity and cost.

[0005] In summary, existing technologies generally employ a reactive control paradigm, meaning compensation or intervention only occurs when the outlet water temperature deviates from the set value or exceeds a safety threshold. The control objective is always to bring the outlet water temperature close to the user-set value, with safety constraints serving only as an upper limit cutoff, which is easily overridden by user settings. This control paradigm fails to fundamentally solve the temperature shock problem caused by the thermal inertia of the heating unit, especially in low-water-volume scenarios for mothers and infants, making it difficult to ensure that the outlet water temperature reaches the target value stably and safely. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a safety access and reachability control method and system for electric water heaters designed for mothers and infants. By changing the control objective from the traditional "approaching the user-set temperature" to "always being within the safe operating range", this invention pre-limits the combination range of heating power and outlet water temperature by performing safety access judgment before heating, constructing a safe reachability range for mothers and infants, and imposing an unoverridden system-level safety constraint on user settings. This avoids temperature shocks caused by thermal inertia from the source of control and improves the inherent safety of electric water heaters in mother and infant usage scenarios.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: On one hand, a method for safety access control and reachability domain control of an electric water heater for mothers and infants, the method comprising the following steps:

[0008] Step 1, Mode Confirmation: Check if the electric water heater is in the mother and baby use mode;

[0009] Step 2, collecting operating parameters: In the mother and baby use mode, collect at least the following parameters before heating is started: water volume, inlet temperature, and target water temperature.

[0010] Step 3, Construction of the maternal and infant safety accessibility domain: Based on the collected parameters of the outflow water volume, the inflow water temperature, and the heating characteristic parameters of the electric water heater, the maternal and infant safety accessibility domain is constructed. The maternal and infant safety accessibility domain is used to limit the allowable combination range of heating power and outflow water temperature in maternal and infant use scenarios.

[0011] Step 4, Safety access judgment before heating: Map the target outlet water temperature parameter and the outlet water volume parameter to the maternal and infant safety reachable domain. When the mapping result falls within the maternal and infant safety reachable domain, the heating unit is allowed to start. When the mapping result does not fall within the maternal and infant safety reachable domain, the heating unit is prohibited from starting.

[0012] Step 5, Maternal and Infant Safety Operation Control: During the heating operation, the heating power is limited to the heating power range corresponding to the maternal and infant safety reachable range, and system-level safety constraints are applied to the target outlet water temperature set by the user. When the operating state corresponding to the target outlet water temperature set by the user exceeds the maternal and infant safety reachable range, the user setting is refused to be executed.

[0013] Step Six, Abnormal Degradation Operation: In the mother and baby usage mode, when an abnormality is detected in a key operating parameter or sensor, the electric water heater is controlled to switch from the current operating state to the lowest safe power operating state.

[0014] By detecting the mother and baby usage pattern, collecting water volume and temperature parameters before heating, constructing a safe access domain for mothers and babies and making a safety access judgment before heating, limiting the power within the access domain during heating and imposing safety constraints on user settings, and switching to the lowest safe power operation when the sensor is abnormal, the temperature shock caused by the thermal inertia of the heating unit can be avoided from the source, significantly reducing the risk of scalding in mother and baby water use scenarios.

[0015] Furthermore, in step three, the construction of the maternal and infant safety accessibility domain, the maternal and infant safety accessibility domain is constructed based on the law of conservation of energy. The following mathematical formula is used to calculate the correspondence between heating power and outlet water temperature under given outlet water volume parameters and inlet water temperature parameters:

[0016]

[0017] in, This indicates heating power, in kW. This indicates the outlet water temperature, in °C. This indicates the inlet water temperature, in degrees Celsius (°C). This indicates water flow rate, expressed in l / min. This represents the density of water, with a value of 1 kg / L. This represents the specific heat capacity of water, and is taken as 4.2 × 10³ J / (kg·℃). This represents the heating efficiency, which is a dimensionless constant.

[0018] By establishing the physical correspondence between heating power and outlet water temperature using the energy conservation formula, and clarifying the meaning of parameters such as water flow rate, inlet water temperature, outlet water temperature, water density, specific heat capacity, and heating efficiency in the formula, a quantifiable calculation basis can be provided for the construction of the safe reach range for mothers and infants, ensuring that the combination range of power and temperature under different operating conditions has a definite physical boundary.

[0019] Furthermore, in step three, the construction of the maternal and infant safety reachability domain, the boundary of the maternal and infant safety reachability domain is defined by the following three boundary conditions:

[0020] The first boundary condition is that the heating power is greater than or equal to the minimum controllable power of the heating unit;

[0021] The second boundary condition is that the heating power is less than or equal to the maximum allowable power of the heating unit;

[0022] The third boundary condition is that the outlet water temperature is less than or equal to the preset upper limit of the safe temperature for mothers and infants.

[0023] By using the minimum controllable power, the maximum allowable power, and the preset upper limit of maternal and infant safety temperature as three boundary conditions for the maternal and infant safety reachable domain, the heating power and water temperature can be constrained within the dual allowable range of hardware capability and biosafety, avoiding scalding caused by unstable heating due to too low power or excessive power and temperature.

[0024] Furthermore, in step five, the system-level safety constraints in the maternal and infant safety operation control include: during the heating operation, real-time monitoring of the distance between the current operating state and the boundary of the maternal and infant safety reachable domain; when the current operating state is detected to be approaching the boundary of the maternal and infant safety reachable domain, the heating power is reduced in advance before the temperature shock occurs.

[0025] By monitoring the distance between the current operating status and the boundary of the maternal and infant safety reach range in real time during the heating process, and reducing the heating power in advance when approaching the boundary instead of waiting for the temperature to overshoot before adjusting, the hysteresis effect caused by thermal inertia can be eliminated, so that the output temperature rises smoothly to the target value without overshooting oscillation.

[0026] Furthermore, in step six, during abnormal degradation operation, the minimum safe power operating state is:

[0027] The heating power is forcibly reduced to the minimum controllable power of the heating unit, and heating is maintained at this minimum controllable power to ensure that users receive a continuous and controllable hot water output;

[0028] If the abnormal state continues for more than the predetermined time and the user does not actively intervene, the system will gradually reduce the heating power until heating stops completely.

[0029] By forcibly switching to the lowest controllable power of the heating unit when the sensor malfunctions, and gradually reducing the power to stop after the malfunction continues for a period of time, it can maintain a controllable minimum hot water output under uncertain conditions of sensor data failure, thus avoiding secondary safety risks to mothers and infants caused by sudden water outages.

[0030] Furthermore, in step four, the safety access judgment before heating, the specific method for mapping the target outlet water temperature parameter and the outlet water volume parameter to the maternal and infant safety reachable domain is as follows: calculate the heating power requirement value required to reach the target outlet water temperature parameter according to the mathematical formula, and determine whether the heating power requirement value simultaneously meets the three conditions: the heating power is greater than or equal to the minimum controllable power of the heating unit, the heating power is less than or equal to the maximum allowable power of the heating unit, and the target outlet water temperature parameter is less than or equal to the preset maternal and infant safety temperature upper limit. Only when all three conditions are met is the mapping result determined to fall within the maternal and infant safety reachable domain.

[0031] By calculating the heating power required to reach the target outlet water temperature according to the energy conservation formula, and simultaneously determining whether the required value meets the three conditions of minimum controllable power, maximum allowable power, and target temperature not exceeding the safety limit, any working conditions that may lead to temperature runaway can be eliminated before heating starts, achieving true pre-entry safety.

[0032] Furthermore, in step two, during the acquisition of operating parameters, the outflow water volume parameter is acquired through a Hall effect flow sensor, and the inflow water temperature parameter is acquired through a negative temperature coefficient thermistor temperature sensor.

[0033] By using a Hall effect flow sensor to collect outflow water parameters and a negative temperature coefficient thermistor temperature sensor to collect inflow water temperature parameters, the key physical quantities required to build a safe and accessible domain for mothers and infants can be obtained in a low-cost and highly reliable sensing manner, which facilitates direct engineering implementation on existing instant electric water heater platforms.

[0034] On the other hand, a safety access and reachability control system for an electric water heater for mothers and infants, applicable to a method for controlling the safety access and reachability of an electric water heater for mothers and infants, the system comprising:

[0035] The parameter acquisition module is electrically connected to the flow sensor, inlet water temperature sensor and outlet water temperature sensor, and is used to acquire water flow parameters, inlet water temperature parameters, target outlet water temperature parameters and real-time outlet water temperature parameters.

[0036] The mother-infant mode recognition module is connected to the parameter acquisition module and the human-computer interaction interface, and is used to detect whether the electric water heater is in mother-infant use mode.

[0037] The maternal and infant safety reachability domain construction module is connected to the parameter acquisition module and has a built-in heating unit characteristic parameter storage unit, which is used to construct the maternal and infant safety reachability domain based on the water volume parameter, the inlet water temperature parameter and the heating characteristic parameter.

[0038] The heating access judgment module is connected to the maternal and infant safety reachable domain construction module and the parameter acquisition module. It is used to map the target water outlet temperature parameter and the water volume parameter to the maternal and infant safety reachable domain and output the judgment result of allowing or prohibiting startup.

[0039] The heating permission control module is connected to the heating access judgment module and is used to control the heating unit to start when startup is allowed, and to keep the heating unit disconnected and output prompt information to the user when startup is prohibited.

[0040] The maternal and infant safety operation control module is connected to the maternal and infant safety reachable domain construction module and the heating unit drive circuit. It is used to limit the heating power within the heating power range corresponding to the maternal and infant safety reachable domain during the heating operation and to apply system-level safety constraints to the target outlet water temperature set by the user.

[0041] The abnormal degradation operation module is connected to the parameter acquisition module and the heating unit drive circuit. It is used to control the electric water heater to switch to the lowest safe power operation state when an abnormality is detected in a key operating parameter or sensor.

[0042] By setting up a parameter acquisition module, a maternal and infant pattern recognition module, a maternal and infant safety reachability domain construction module, a heating access judgment module, a heating permission control module, a maternal and infant safety operation control module, and an abnormal degradation operation module, and by cooperating with each other according to the above logic, a complete hardware and firmware collaborative safety control system can be formed to achieve proactive safety constraints on the entire heating process.

[0043] Furthermore, the heating unit characteristic parameter storage unit built into the maternal and infant safety reachability domain construction module stores at least the following parameters:

[0044] The minimum controllable power of the heating unit, the maximum allowable power of the heating unit, the heating efficiency, and the preset upper limit of the safe temperature for mothers and babies;

[0045] The maternal and infant safety reachability construction module is based on the law of conservation of energy, and combines the parameters stored in the heating unit characteristic parameter storage unit with the real-time collected water volume parameters and inlet water temperature parameters to dynamically construct the maternal and infant safety reachability domain.

[0046] By incorporating a parameter storage unit within the maternal and infant safety reachability domain construction module, which stores the minimum controllable power, maximum allowable power, heating efficiency, and upper limit of maternal and infant safe temperature of the heating unit, and dynamically constructing the reachability domain based on the law of conservation of energy and real-time collected water volume and inlet water temperature, the safe operating boundary can be adjusted in real time according to water usage conditions to adapt to the maternal and infant water needs under different seasons and water pressure conditions.

[0047] Furthermore, the sampling period of the parameter acquisition module is no greater than 200ms;

[0048] The mother-infant mode recognition module responds to the user actively selecting and triggering the mother-infant usage mode through the control panel or remote control, or automatically identifies and suggests entering the mother-infant usage mode based on the detected water usage characteristics.

[0049] When the heating permission control module is prohibited from starting, it will issue a prompt message to the user through the display screen, voice prompt or indicator light, suggesting that the user adjust the water conditions.

[0050] By controlling the sampling period of the parameter acquisition module to within 200ms, the mother-infant pattern recognition module can respond to user active selection or automatically identify water usage characteristics. When startup is prohibited, it can prompt the user to adjust water usage conditions through the display screen, voice, or indicator lights. This ensures that the response speed of the control system meets the requirements of thermal inertia compensation, while providing clear and operable feedback to the user and improving the user-friendliness of human-computer interaction.

[0051] Compared with existing technologies, the safety access and reachability control method and system for an electric water heater for mothers and infants has the following advantages:

[0052] I. This invention introduces a safety access judgment mechanism before heating, constructing a safe reach domain for mothers and infants based on real-time collected operating parameters and the heating characteristic parameters of the electric water heater. This shifts the control objective from simply approaching the user-set temperature to ensuring the water heater remains within a safe operating range. It eliminates all potential temperature runaway conditions before heating begins, strictly limits the heating power range during operation, and imposes non-overridden system-level safety constraints on user settings. This proactively predicts and avoids temperature overshoot and oscillations caused by the thermal inertia of the heating unit, thereby preventing temperature shocks at the source and significantly improving the inherent safety of electric water heaters in mother-and-infant water use scenarios.

[0053] Second, this invention employs an abnormal degradation operation mechanism. When an abnormality in key operating parameters or sensor failure is detected, the water heater is first switched to the lowest safe power state to maintain continuous and controllable hot water output. If the abnormal state persists for more than a predetermined time and the user does not actively intervene, the power is gradually reduced until heating is completely stopped. This avoids sudden water outages or temperature runaways caused by sensor failures, reducing secondary safety risks. Furthermore, this invention requires no additional complex hardware structure; it can be implemented simply by optimizing the control logic and utilizing existing conventional sensing elements. This facilitates direct engineering implementation on existing water heater platforms, effectively controlling product modification costs.

[0054] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0056] Figure 1 This is a block diagram of the overall structure of the system of the present invention;

[0057] Figure 2 This is a flowchart illustrating the control method of the present invention. Detailed Implementation

[0058] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0059] Example

[0060] This invention discloses a safety access and reachability control method and system for electric water heaters designed for mothers and infants. It is applicable to instantaneous and rapid-heating electric water heaters, and is particularly suitable for mother-and-infant water use scenarios. This invention introduces a safety access judgment before heating, constructs a mother-and-infant safe reachability domain, pre-limits the combination range of heating power and outlet water temperature, and imposes non-overridden system-level safety constraints on user settings. Simultaneously, it implements degraded operation rather than direct shutdown under abnormal operating conditions, thereby preventing temperature shocks caused by thermal inertia from the source and improving the inherent safety of electric water heaters in mother-and-infant usage scenarios.

[0061] Specifically, such as Figure 1 As shown, the system mainly includes a parameter acquisition module, a maternal and infant pattern recognition module, a maternal and infant safety reachability domain construction module, a heating access judgment module, a heating permission control module, a maternal and infant safety operation control module, and an abnormal degradation operation module.

[0062] Specifically, the parameter acquisition module is electrically connected to the flow sensor, inlet water temperature sensor, and outlet water temperature sensor, respectively. The parameter acquisition module is used to collect water flow parameters, inlet water temperature parameters, target outlet water temperature parameters, and real-time outlet water temperature parameters. The sampling period of the parameter acquisition module is no greater than 200ms.

[0063] The maternal and infant mode recognition module is connected to both the parameter acquisition module and the human-machine interface. This module detects whether the electric water heater is in maternal and infant use mode. It can respond to user-initiated selection of maternal and infant use mode via the control panel or remote control, or it can automatically identify and suggest entering maternal and infant use mode based on detected water usage characteristics.

[0064] The maternal and infant safety reachability domain construction module is connected to the parameter acquisition module. The module includes a built-in heating unit characteristic parameter storage unit. This unit stores at least the heating unit's minimum controllable power, maximum allowable power, heating efficiency, and preset upper limit for maternal and infant safety temperature. The module is used to construct the maternal and infant safety reachability domain based on water volume parameters, inlet water temperature parameters, and heating characteristic parameters.

[0065] The heating access judgment module is connected to both the maternal and infant safety reachability domain construction module and the parameter acquisition module. The heating access judgment module maps the target outlet water temperature parameter and water volume parameter to the maternal and infant safety reachability domain and outputs a judgment result indicating whether to allow or prohibit the start-up.

[0066] The heating permission control module is connected to the heating access judgment module. The heating permission control module controls the heating unit to start when startup is permitted, keeps the heating unit off when startup is prohibited, and outputs a prompt message to the user. When startup is prohibited, the heating permission control module can issue a prompt message to the user through the display screen, voice prompts, or indicator lights, suggesting that the user adjust the water usage conditions.

[0067] The maternal and infant safety operation control module is connected to both the maternal and infant safety reachability domain construction module and the heating unit drive circuit. During heating operation, the maternal and infant safety operation control module limits the heating power to the range corresponding to the maternal and infant safety reachability domain and applies system-level safety constraints to the user-set target outlet water temperature.

[0068] The abnormal degradation operation module is connected to both the parameter acquisition module and the heating unit drive circuit. This module controls the electric water heater to switch to the lowest safe power operating state when abnormalities are detected in critical operating parameters or sensors.

[0069] Specifically, such as Figure 2 As shown, the method specifically includes the following steps:

[0070] Step 1, Pattern Confirmation:

[0071] Check if the electric water heater is in mother-and-baby use mode. If not in mother-and-baby use mode, the water heater operates according to the normal constant temperature control method. If in mother-and-baby use mode, proceed to the next steps.

[0072] Specifically, the maternal and infant mode recognition module monitors the input signals of the human-computer interaction interface and the water usage characteristic signals collected by the parameter acquisition module in real time. When the user presses the maternal and infant mode button on the control panel or remote control, the maternal and infant mode recognition module receives the corresponding trigger signal and determines that the water heater has entered the maternal and infant use mode. When the maternal and infant mode recognition module collects a continuous and stable low-flow water usage signal through the parameter acquisition module, and the duration exceeds a preset threshold, it automatically identifies it as a possible maternal and infant water usage scenario and sends a suggestion to the user through the human-computer interaction interface whether to enter the maternal and infant use mode.

[0073] Step 2, collect runtime parameters:

[0074] In the mother and baby use mode, at least the following parameters are collected before heating is started: water volume, water inlet temperature, and target water outlet temperature.

[0075] Specifically, the water flow rate parameter is acquired through a Hall effect flow sensor. The Hall effect flow sensor is installed on the inlet pipe of the electric water heater. When water flows through, the Hall effect flow sensor generates a pulse signal proportional to the water flow rate. The parameter acquisition module counts and converts the pulse signals to obtain the real-time water flow rate parameter, in units of l / min.

[0076] The inlet water temperature parameter is acquired using a negative temperature coefficient (NTC) thermistor. This NTC thermistor is installed on the inlet pipe of the electric water heater, and its resistance changes with temperature. The parameter acquisition module measures and calculates the resistance value of the thermistor to obtain the real-time inlet water temperature parameter, in degrees Celsius (°C).

[0077] The target outlet water temperature parameter is obtained through the human-machine interface. Users can set the target outlet water temperature using the temperature adjustment buttons on the control panel. The parameter acquisition module reads this set value as the target outlet water temperature parameter, in °C.

[0078] Step 3, Building a safe and accessible domain for mothers and infants:

[0079] Based on the collected parameters of water output, water inlet temperature, and heating characteristics of the electric water heater, a maternal and infant safety reachability domain is constructed. This domain limits the permissible combination of heating power and water output temperature in maternal and infant use scenarios.

[0080] Specifically, the maternal and infant safety accessibility domain construction module is based on the law of conservation of energy. The following mathematical formula is used to calculate the relationship between heating power and outlet water temperature under given outlet water volume and inlet water temperature parameters:

[0081]

[0082] in, This indicates heating power, measured in kW. Heating power refers to the electrical energy consumed by the heating unit of an electric water heater per unit time, used to heat water from the inlet temperature to the outlet temperature. This indicates the outlet water temperature, expressed in °C. The outlet water temperature refers to the water temperature at the outlet of the electric water heater, which is the actual water temperature used by the user. This indicates the inlet water temperature, expressed in °C. The inlet water temperature refers to the temperature of tap water entering the electric water heater; its value varies depending on the season and region. This indicates water flow rate, measured in l / min. Water flow rate refers to the volume of water passing through the electric water heater per unit time, and its value is determined by the user's water demand and the tap water pressure. This represents the density of water, with a value of 1 kg / L. The density of water refers to the mass of a unit volume of water, which is approximately 1 kg / L at normal temperature and pressure. This represents the specific heat capacity of water, with a value of 4.2 × 10³ J / (kg·℃). The specific heat capacity of water refers to the amount of heat required to raise the temperature of a unit mass of water by a unit amount; it is a physical constant. This represents heating efficiency, a dimensionless constant. Heating efficiency refers to the efficiency with which the heating unit of an electric water heater converts electrical energy into heat energy; its value is less than 1 and is determined by the material, structure, and manufacturing process of the heating unit. The heating efficiency parameter is pre-stored in the heating unit characteristic parameter storage unit.

[0083] The boundaries of the maternal and infant safety reach domain are defined by the following three boundary conditions:

[0084] The first boundary condition is that the heating power is greater than or equal to the minimum controllable power of the heating unit. The minimum controllable power of the heating unit refers to the minimum power value at which the heating unit can operate stably. When the heating power is lower than this value, the heating unit cannot operate normally, and unstable heating or failure to heat may occur. The minimum controllable power parameter of the heating unit is pre-stored in the heating unit characteristic parameter storage unit.

[0085] The second boundary condition is that the heating power is less than or equal to the maximum allowable power of the heating unit. The maximum allowable power of the heating unit refers to the maximum power value at which the heating unit can operate safely. When the heating power exceeds this value, the heating unit may experience safety problems such as overheating or burnout. The maximum allowable power parameter of the heating unit is pre-stored in the heating unit characteristic parameter storage unit.

[0086] The third boundary condition is that the outlet water temperature is less than or equal to the preset upper limit of the safe temperature for mothers and babies. The preset upper limit of the safe temperature for mothers and babies refers to the highest safe water temperature suitable for use by mothers and babies; exceeding this temperature may cause burns to mothers and babies. The preset upper limit of the safe temperature for mothers and babies is stored in advance in the heating unit characteristic parameter storage unit.

[0087] The maternal and infant safety reachability domain construction module dynamically constructs the maternal and infant safety reachability domain under the current operating conditions based on the aforementioned mathematical formula and three boundary conditions. The maternal and infant safety reachability domain is a two-dimensional region, with the horizontal axis representing the outlet water temperature and the vertical axis representing the heating power. Any combination of heating power and outlet water temperature within this region is safe and achievable.

[0088] Step 4, Safety access assessment before heating:

[0089] The target outlet water temperature and flow rate parameters are mapped to a maternal and infant safety reachable region. The heating unit is allowed to start when the mapping result falls within this region. The heating unit is prohibited from starting when the mapping result does not fall within this region.

[0090] Specifically, the target outlet water temperature and outlet water volume parameters are substituted into the above mathematical formula to calculate the heating power required to reach the target outlet water temperature. Then, it is determined whether this heating power requirement simultaneously meets the following three conditions:

[0091] The first condition is that the heating power requirement is greater than or equal to the minimum controllable power of the heating unit.

[0092] The second condition is that the heating power requirement is less than or equal to the maximum allowable power of the heating unit.

[0093] The third condition is that the target outlet water temperature parameter is less than or equal to the preset upper limit of the safe temperature for mothers and infants.

[0094] Only when all three conditions are met is the mapping result determined to fall within the maternal and infant safety reachable region, and the heating access judgment module outputs a signal allowing start to the heating permission control module. If any one condition is not met, the mapping result is determined to fall outside the maternal and infant safety reachable region, and the heating access judgment module outputs a signal prohibiting start to the heating permission control module.

[0095] When the heating permit control module receives a signal allowing startup, it controls the heating unit to start and begin heating. When the heating permit control module receives a signal prohibiting startup, it keeps the heating unit off and issues a prompt to the user via the display screen, voice prompts, or indicator lights, suggesting that the user adjust the water usage conditions. For example, if the water flow is too low, the user is prompted to increase the water flow; if the target outlet water temperature is too high, the user is prompted to lower the target outlet water temperature.

[0096] Step 5, Maternal and Infant Safety Operation Control:

[0097] During heating operation, the heating power is limited to the range corresponding to the maternal and infant safety reachability zone, and system-level safety constraints are applied to the user-set target outlet water temperature. If the operating state corresponding to the user-set target outlet water temperature exceeds the maternal and infant safety reachability zone, the user setting will be rejected.

[0098] Specifically, the maternal and infant safety operation control module acquires the outflow water volume and inflow water temperature parameters collected by the parameter acquisition module in real time, and updates the maternal and infant safety reachability range in real time. The maternal and infant safety operation control module limits the actual heating power of the heating unit to the heating power range corresponding to the updated maternal and infant safety reachability range.

[0099] System-level safety constraints include real-time monitoring of the distance between the current operating state and the boundary of the maternal and infant safety reachable zone during heating operation. When the current operating state is detected to be approaching the boundary of the maternal and infant safety reachable zone, the heating power is reduced in advance before a temperature shock occurs.

[0100] Specifically, the maternal and infant safety operation control module calculates in real time the position of the current heating power and current outlet water temperature within the maternal and infant safety reachable zone, and calculates the distance between the current operating state and each boundary of the maternal and infant safety reachable zone. When the distance to any boundary is less than the preset safety distance threshold, the maternal and infant safety operation control module gradually reduces the heating power at a preset rate, causing the operating state to move towards the center of the maternal and infant safety reachable zone, thereby avoiding temperature shocks.

[0101] When a user resets the target outlet water temperature via the human-machine interface during heating operation, the maternal and infant safety operation control module first maps the new target outlet water temperature parameter and the current outlet water volume parameter to the updated maternal and infant safety reachable domain. If the mapping result falls within the maternal and infant safety reachable domain, the user setting is executed, and the heating power is adjusted to the corresponding value. If the mapping result does not fall within the maternal and infant safety reachable domain, the user setting is rejected, and a prompt message is sent to the user via the human-machine interface explaining why the setting cannot be executed.

[0102] Step 6, abnormal degradation operation:

[0103] In the mother and baby use mode, when an abnormality is detected in a key operating parameter or sensor, the electric water heater is controlled to switch from the current operating state to the lowest safe power operating state.

[0104] Specifically, the abnormal degradation operation module monitors the various parameter signals output by the parameter acquisition module in real time. When a parameter signal is detected to be outside the normal range, or when a sensor has no signal output, it is determined that a critical operating parameter or sensor is abnormal.

[0105] When an anomaly is detected, the anomaly degradation operation module immediately sends a control signal to the heating unit drive circuit to forcibly reduce the heating power to the minimum controllable power of the heating unit, and maintains heating at this minimum controllable power to ensure that the user obtains continuous and controllable hot water output.

[0106] Simultaneously, the abnormal degradation operation module starts a timer. If the abnormal state persists for more than the predetermined time and the user does not intervene, the system gradually reduces the heating power until heating stops completely. The predetermined time parameter is stored in the system beforehand.

[0107] The following is a complete running example to further illustrate the implementation process of the present invention.

[0108] For example, the heating unit characteristics of a certain instant electric water heater are as follows: the minimum controllable power of the heating unit is 1kw, the maximum allowable power of the heating unit is 8kw, the heating efficiency is 0.95, and the preset upper limit of the safe temperature for mothers and infants is 42℃.

[0109] When a user presses the Mother and Baby Mode button on the control panel, the Mother and Baby Mode Recognition Module receives the trigger signal and determines that the electric water heater has entered the Mother and Baby Use Mode.

[0110] When the user turns on the tap, the parameter acquisition module detects a water flow rate of 5 L / min and an inlet water temperature of 15℃. The user then sets the target outlet water temperature to 38℃ via the control panel.

[0111] The maternal and infant safety reachability construction module constructs the maternal and infant safety reachability domain based on the collected outflow water volume parameters, inflow water temperature parameters, and heating unit characteristic parameters.

[0112] First, calculate the relationship between heating power and outlet water temperature:

[0113]

[0114] Simplifying, we get:

[0115]

[0116] Then, the range of the maternal and infant safety reachable domain is determined based on the three boundary conditions:

[0117] First boundary condition: ;

[0118] Second boundary condition: ;

[0119] Third boundary condition: ;

[0120] Substituting the first boundary condition into the above formula, we get:

[0121]

[0122] Solving for: ;

[0123] Substituting the second boundary condition into the above formula, we get:

[0124]

[0125] Solving for: ;

[0126] Based on the third boundary condition, the final range of outlet water temperature corresponding to the maternal and infant safety reachable domain is 17.71℃ to 36.72℃, and the corresponding heating power range is 1kW to 8kW.

[0127] Next, a safety access assessment is performed before heating. The user-set target outlet water temperature is 38℃, which is greater than 36.72℃, and therefore does not meet the third boundary condition. Thus, the mapping result is determined not to fall within the maternal and infant safety reachable range.

[0128] When the heating permit control module receives a signal prohibiting startup, it keeps the heating unit disconnected and displays a prompt message to the user on the screen, reminding the user that the current target outlet water temperature is too high and to lower the target outlet water temperature to below 36℃.

[0129] After seeing the prompt, the user adjusted the target water temperature to 36℃.

[0130] Recalculate the heating power required to achieve the target outlet water temperature of 36℃:

[0131]

[0132] Determine whether the heating power requirement meets three conditions:

[0133] The first condition, 7.74kw ≥ 1kw, is met.

[0134] The second condition: 7.74kw ≤ 8kw, is met.

[0135] The third condition: 36℃≤42℃, is met.

[0136] If all three conditions are met, the mapping result is determined to fall within the maternal and infant safety reachable domain.

[0137] Upon receiving a signal indicating permission to start, the heating permit control module controls the heating unit to begin heating.

[0138] During heating operation, the maternal and infant safety operation control module collects the outflow water volume and inflow water temperature parameters in real time and updates the maternal and infant safety reach range in real time. The maternal and infant safety operation control module limits the actual heating power of the heating unit to about 7.74kw, so that the outflow water rises steadily to 36℃.

[0139] When a user accidentally turns off the tap and the water flow drops to 4 L / min, the maternal and infant safety operation control module detects the change in water flow in real time and immediately updates the maternal and infant safety reachability domain.

[0140] Recalculate the relationship between heating power and outlet water temperature:

[0141]

[0142] Simplifying, we get:

[0143]

[0144] The updated maternal and infant safety reachability range is determined based on three boundary conditions:

[0145] First boundary condition: ;

[0146] Solving for: ;

[0147] Second boundary condition: ;

[0148] Solving for: ;

[0149] Based on the third boundary condition, the updated maternal and infant safety reachable domain corresponds to an outlet water temperature range of 18.39℃ to 42℃, and a corresponding heating power range of 1kW to 8kW.

[0150] The user-set target outlet water temperature is still 36℃. Calculate the required heating power at this temperature:

[0151]

[0152] The maternal and infant safety operation control module monitored the current heating power in real time and found it to be 7.74 kW, which deviated from the updated heating power requirement of 6.19 kW. Simultaneously, the module calculated the distance between the current operating state and the upper boundary of the maternal and infant safety reachable domain, discovering that the distance was less than the preset safety distance threshold. Therefore, the module gradually reduced the heating power to 6.19 kW at a preset rate, maintaining the outlet water temperature stably at 36℃ and preventing temperature shocks.

[0153] If the inlet water temperature sensor malfunctions during use and there is no signal output, the abnormal degradation operation module will detect the sensor malfunction and immediately send a control signal to the heating unit drive circuit to forcibly reduce the heating power to 1kW and maintain heating at 1kW to ensure that the user receives a continuous and controllable hot water output.

[0154] Simultaneously, the abnormal degradation operation module starts a timer. If the inlet water temperature sensor returns to normal within the predetermined time, the abnormal state is resolved, and the system automatically switches back to normal operation. If the abnormal state persists beyond the predetermined time and the user does not intervene, the system gradually reduces the heating power until heating stops completely.

[0155] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for safety access control and reachability domain control of an electric water heater for mothers and infants, characterized in that, The method includes the following steps: Step 1, Mode Confirmation: Check if the electric water heater is in the mother and baby use mode; Step 2, collecting operating parameters: In the mother and baby use mode, collect at least the following parameters before heating is started: water volume, inlet temperature, and target water temperature. Step 3, Construction of the maternal and infant safety accessibility domain: Based on the collected parameters of the outflow water volume, the inflow water temperature, and the heating characteristic parameters of the electric water heater, the maternal and infant safety accessibility domain is constructed. The maternal and infant safety accessibility domain is used to limit the allowable combination range of heating power and outflow water temperature in maternal and infant use scenarios. Step 4, Safety access judgment before heating: Map the target outlet water temperature parameter and the outlet water volume parameter to the maternal and infant safety reachable domain. When the mapping result falls within the maternal and infant safety reachable domain, the heating unit is allowed to start. When the mapping result does not fall within the maternal and infant safety reachable domain, the heating unit is prohibited from starting. Step 5, Maternal and Infant Safety Operation Control: During the heating operation, the heating power is limited to the heating power range corresponding to the maternal and infant safety reachable range, and system-level safety constraints are applied to the target outlet water temperature set by the user. When the operating state corresponding to the target outlet water temperature set by the user exceeds the maternal and infant safety reachable range, the user setting is refused to be executed. Step Six, Abnormal Degradation Operation: In the mother and baby usage mode, when an abnormality is detected in a key operating parameter or sensor, the electric water heater is controlled to switch from the current operating state to the lowest safe power operating state.

2. The safety access and reachability control method for an electric water heater for mothers and infants according to claim 1, characterized in that, In step three, the construction of the maternal and infant safety reachability domain is based on the law of conservation of energy. The following mathematical formula is used to calculate the correspondence between heating power and outlet water temperature under given outlet water volume parameters and inlet water temperature parameters: in, This indicates heating power, in kW. This indicates the outlet water temperature, in °C. This indicates the inlet water temperature, in degrees Celsius (°C). This indicates water flow rate, expressed in l / min. This represents the density of water, with a value of 1 kg / L. This represents the specific heat capacity of water, and is taken as 4.2 × 10³ J / (kg·℃). This represents the heating efficiency, which is a dimensionless constant.

3. The safety access and reachability control method for an electric water heater for mothers and infants according to claim 1, characterized in that, In step three, the construction of the maternal and infant safety reachability domain is defined by the following three boundary conditions: The first boundary condition is that the heating power is greater than or equal to the minimum controllable power of the heating unit; The second boundary condition is that the heating power is less than or equal to the maximum allowable power of the heating unit; The third boundary condition is that the outlet water temperature is less than or equal to the preset upper limit of the safe temperature for mothers and infants.

4. The safety access and reachability control method for an electric water heater for mothers and infants according to claim 1, characterized in that, In step five, the system-level safety constraints in the maternal and infant safety operation control include: during the heating operation, real-time monitoring of the distance between the current operating state and the boundary of the maternal and infant safety reachable domain; when the current operating state is detected to be approaching the boundary of the maternal and infant safety reachable domain, the heating power is reduced in advance before the temperature shock occurs.

5. The safety access and reachability control method for an electric water heater for mothers and infants according to claim 1, characterized in that, In step six, during abnormal degradation operation, the minimum safe power operating state is as follows: The heating power is forcibly reduced to the minimum controllable power of the heating unit, and heating is maintained at this minimum controllable power to ensure that users receive a continuous and controllable hot water output; If the abnormal state continues for more than the predetermined time and the user does not actively intervene, the system will gradually reduce the heating power until heating stops completely.

6. The safety access and reachability control method for an electric water heater for mothers and infants according to claim 1, characterized in that, In step four, the safety access judgment before heating, the specific method for mapping the target outlet water temperature parameter and the outlet water volume parameter to the maternal and infant safety reachable domain is as follows: calculate the heating power requirement value required to reach the target outlet water temperature parameter according to the mathematical formula, and determine whether the heating power requirement value simultaneously meets the three conditions: the heating power is greater than or equal to the minimum controllable power of the heating unit, the heating power is less than or equal to the maximum allowable power of the heating unit, and the target outlet water temperature parameter is less than or equal to the preset maternal and infant safety temperature upper limit. Only when all three conditions are met is the mapping result determined to fall within the maternal and infant safety reachable domain.

7. The safety access and reachability control method for an electric water heater for mothers and infants according to claim 1, characterized in that, In step two, during the acquisition of operating parameters, the outflow water volume parameter is acquired through a Hall effect flow sensor, and the inflow water temperature parameter is acquired through a negative temperature coefficient thermistor temperature sensor.

8. A safety access and reachability control system for an electric water heater for mothers and infants, applicable to the safety access and reachability control method for an electric water heater for mothers and infants as described in any one of claims 1-7, characterized in that, The system consists of: The parameter acquisition module is electrically connected to the flow sensor, inlet water temperature sensor and outlet water temperature sensor, and is used to acquire water flow parameters, inlet water temperature parameters, target outlet water temperature parameters and real-time outlet water temperature parameters. The mother-infant mode recognition module is connected to the parameter acquisition module and the human-computer interaction interface, and is used to detect whether the electric water heater is in mother-infant use mode. The maternal and infant safety reachability domain construction module is connected to the parameter acquisition module and has a built-in heating unit characteristic parameter storage unit, which is used to construct the maternal and infant safety reachability domain based on the water volume parameter, the inlet water temperature parameter and the heating characteristic parameter. The heating access judgment module is connected to the maternal and infant safety reachable domain construction module and the parameter acquisition module. It is used to map the target water outlet temperature parameter and the water volume parameter to the maternal and infant safety reachable domain and output the judgment result of allowing or prohibiting startup. The heating permission control module is connected to the heating access judgment module and is used to control the heating unit to start when startup is allowed, and to keep the heating unit disconnected and output prompt information to the user when startup is prohibited. The maternal and infant safety operation control module is connected to the maternal and infant safety reachable domain construction module and the heating unit drive circuit. It is used to limit the heating power within the heating power range corresponding to the maternal and infant safety reachable domain during the heating operation and to apply system-level safety constraints to the target outlet water temperature set by the user. The abnormal degradation operation module is connected to the parameter acquisition module and the heating unit drive circuit. It is used to control the electric water heater to switch to the lowest safe power operation state when an abnormality is detected in a key operating parameter or sensor.

9. A safety access and reachability control system for an electric baby water heater according to claim 8, characterized in that, The heating unit characteristic parameter storage unit built into the maternal and infant safety reachability domain construction module stores at least the following parameters: The minimum controllable power of the heating unit, the maximum allowable power of the heating unit, the heating efficiency, and the preset upper limit of the safe temperature for mothers and babies; The maternal and infant safety reachability construction module is based on the law of conservation of energy, and combines the parameters stored in the heating unit characteristic parameter storage unit with the real-time collected water volume parameters and inlet water temperature parameters to dynamically construct the maternal and infant safety reachability domain.

10. A safety access and reachability control system for an electric baby water heater according to claim 8, characterized in that, The sampling period of the parameter acquisition module is no more than 200ms; The mother-infant mode recognition module responds to the user actively selecting and triggering the mother-infant usage mode through the control panel or remote control, or automatically identifies and suggests entering the mother-infant usage mode based on the detected water usage characteristics. When the heating permission control module is prohibited from starting, it will issue a prompt message to the user through the display screen, voice prompt or indicator light, suggesting that the user adjust the water conditions.

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