Control method of gas water heater and gas water heater

Abstract

The invention relates to the technical field of hot water supply equipment, and discloses a control method of a gas water heater and the gas water heater. The control method comprises the steps that real-time theoretical current is calculated in real time based on the real-time water inlet temperature, the target temperature and the real-time water flow; when the gas water heater is in a variable temperature control stage, real-time compensation current of the gas water heater is calculated in real time based on the change condition of the real-time predicted current; responding to the constant temperature control stage of the gas water heater, and taking the real-time compensation current obtained by the last calculation as the target compensation current; and target control current of the gas water heater is calculated in real time based on the target compensation current, the real-time prediction current and the real-time theoretical current, and proportional valve current of the gas water heater is adjusted based on the target control current. Therefore, the variable quantity of the real-time predicted current in the variable temperature control stage is used as the adjusting reference of the constant temperature control stage, incremental output of the real-time predicted current is achieved, the control stability is guaranteed, and the response speed is increased by adopting parallel control of theoretical calculation and a feedback control algorithm.

Description

Technical Field

[0001] The present invention relates to the technical field of hot water supply equipment, and in particular to a control method for a gas water heater and a gas water heater. Background Art

[0002] In the process of constant temperature control for water heaters, a method combining theoretical calculations with feedback control algorithms is typically used to control the outlet water temperature. First, a theoretical target load is calculated to control the heating of the gas water heater. When the outlet water temperature approaches the target temperature, a feedback control algorithm is used to control the outlet water temperature. However, this method cannot provide timely feedforward control when the gas water heater load changes, resulting in significant temperature overshoot. Summary of the Invention

[0003] The first technical problem solved by the present invention is to provide a control method for a gas water heater, which effectively solves the problem of failure to timely perform feedforward control according to load changes of the gas water heater and large temperature overshoot.

[0004] The second technical problem solved by the present invention is to provide a gas water heater, which effectively solves the problem of failure to timely perform feedforward control according to load changes of the gas water heater and large temperature overshoot.

[0005] The first technical problem mentioned above is solved by the following technical solution:

[0006] A method for controlling a gas water heater, the method comprising:

[0007] Get the real-time water inlet temperature, target temperature and real-time water flow of the gas water heater;

[0008] Calculate the real-time theoretical current based on the real-time inlet water temperature, target temperature and real-time water flow;

[0009] When the gas water heater is in the variable temperature control stage, the real-time compensation current of the gas water heater is calculated in real time based on the real-time predicted current change output by the gas water heater's active disturbance rejection control algorithm;

[0010] In response to the gas water heater entering the constant temperature control stage, using the most recently calculated real-time compensation current as the target compensation current;

[0011] When the gas water heater is in the constant temperature control stage, the target control current of the gas water heater is calculated in real time based on the target compensation current, the real-time predicted current and the real-time theoretical current, and the proportional valve current of the gas water heater is adjusted based on the target control current.

[0012] Compared with the background technology, the control method of the gas water heater of the present invention has the following beneficial effects:

[0013] When the gas water heater is in the constant temperature control stage, the target control current of the gas water heater is calculated in real time based on the target compensation current, the real-time predicted current, and the real-time theoretical current, and the proportional valve current of the gas water heater is adjusted based on the target control current. In this way, the gas water heater is controlled by combining theoretical calculation with a feedback control algorithm in parallel. When the load of the gas water heater changes, feedforward control can be performed in a timely manner, thereby improving the response speed and avoiding temperature overshoot. At the same time, the real-time compensation current of the gas water heater is calculated in real time based on the change of the real-time predicted current output by the active disturbance rejection control algorithm of the gas water heater, thereby statistically analyzing the change of the implementation predicted current in the variable temperature control stage. When the gas water heater enters the constant temperature control stage, the most recently calculated real-time compensation current is used as the target compensation current, and the change of the real-time predicted current in the variable temperature control stage is used as the adjustment reference for the constant temperature control stage. When calculating the target control current, the real-time predicted current can be converted into an incremental output, thereby avoiding the problem of control signal superposition inconsistency between the real-time theoretical current and the real-time predicted current, thereby ensuring control stability.

[0014] In one embodiment, based on the real-time predicted current change output by the active disturbance rejection control algorithm, the real-time compensation current is calculated in real time, including:

[0015]

[0016] in, is the real-time compensation current currently calculated, is the real-time compensation current calculated last time, The real-time predicted current output by the active disturbance rejection control algorithm is It is the real-time predicted current of the last output of the active disturbance rejection control algorithm.

[0017] In one embodiment, the initial value of the real-time compensation current is zero, and the initial value of the real-time prediction current is zero.

[0018] In one embodiment, the target control current of the gas water heater is calculated in real time based on the target compensation current, the real-time predicted current, and the real-time theoretical current, including:

[0019]

[0020] Among them, I b To control the current, is the real-time theoretical current, To predict the current in real time, I s is the target compensation current.

[0021] In one embodiment, the real-time theoretical current is calculated based on the real-time inlet water temperature, the target temperature, and the real-time water flow rate, including:

[0022] Determine the real-time theoretical load based on the real-time inlet water temperature, target temperature and real-time water flow;

[0023] Based on the real-time theoretical load, the real-time theoretical current is determined.

[0024] In one embodiment, the method further comprises:

[0025] After the gas water heater is ignited, the current is calculated and predicted in real time based on the active disturbance rejection control algorithm.

[0026] In one embodiment, the method further comprises:

[0027] When the gas water heater is in the temperature-variable control stage, the real-time theoretical current is used as the target control current, and the proportional valve current is adjusted based on the target control current.

[0028] In one embodiment, the method further comprises:

[0029] When the gas water heater is in the constant temperature control stage, if the change of the real-time theoretical load of the gas water heater reaches a preset change value, the gas water heater is controlled to enter the variable temperature control stage;

[0030] Alternatively, after the gas water heater is ignited, the gas water heater is controlled to enter a temperature variable control stage.

[0031] In one embodiment, the method further comprises:

[0032] When the gas water heater is in the variable temperature control stage, if the combustion time of the gas water heater reaches the preset time, or the outlet water temperature of the gas water heater reaches the target temperature, the gas water heater is controlled to enter the constant temperature control stage.

[0033] The second technical problem mentioned above is solved by the following technical solution:

[0034] A gas water heater includes a controller, wherein the controller is used in the control method of the gas water heater described in any one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 1 is a flow chart of a method for controlling a gas water heater according to an embodiment of the present invention;

[0037] Figure 2 1 is a flow chart of calculating the real-time theoretical current in the control method of the gas water heater according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0040] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0041] In the constant temperature control process for water heaters, a method combining theoretical calculations with feedback control algorithms is typically used to control the outlet water temperature. First, a theoretical target load is calculated to control the heating of the gas water heater. When the outlet water temperature approaches the target temperature, a feedback control algorithm is used to control the outlet water temperature. However, this method cannot provide timely feedforward control when the gas water heater load fluctuates, resulting in significant temperature overshoot. Furthermore, due to the cascade delay of the control signal and the amplified mismatch of the theoretical calculation under dynamic conditions, this method suffers from slow response in the later stages of control, making it difficult to quickly adjust to large disturbances.

[0042] In related technologies, there are also methods that combine theoretical calculations with feedback control algorithms in parallel to control the outlet water temperature of water heaters. This method improves response speed by superimposing the theoretical calculations with the output of the feedback control algorithm. However, this method directly superimposes the theoretical calculations with the control signals output by the feedback control algorithm, resulting in a lack of coordination between the two control methods, which is prone to phase conflicts and ultimately leads to output oscillation and temperature overshoot.

[0043] To address the above technical problems, the present invention provides a control method for a gas water heater. When the gas water heater is in a constant temperature control stage, a target control current of the gas water heater is calculated in real time based on a target compensation current, a real-time predicted current, and a real-time theoretical current. The proportional valve current of the gas water heater is adjusted based on the target control current. Thus, the gas water heater is controlled by combining theoretical calculation with a feedback control algorithm in parallel. When the load of the gas water heater changes, feedforward control can be performed in a timely manner, thereby improving response speed and avoiding temperature overshoot. At the same time, the real-time compensation current of the gas water heater is calculated in real time based on changes in the real-time predicted current output by an active disturbance rejection control algorithm of the gas water heater. The change in the predicted current during the variable temperature control stage is statistically analyzed. When the gas water heater enters the constant temperature control stage, the most recently calculated real-time compensation current is used as the target compensation current. The change in the real-time predicted current during the variable temperature control stage is used as the adjustment reference for the constant temperature control stage. When calculating the target control current, the real-time predicted current can be converted into an incremental output, thereby avoiding the problem of control signal superposition inconsistency between the real-time theoretical current and the real-time predicted current, thereby ensuring control stability.

[0044] The following combination Figures 1 to 2 , describing embodiments of the present invention.

[0045] According to an embodiment of the present invention, in one aspect, a control method for a gas water heater is provided. Figure 1 FIG. 1 is a flow chart of a method for controlling a gas water heater according to an embodiment of the present invention. Figure 1 As shown, the method may include the following steps:

[0046] Step S101, obtaining the real-time water inlet temperature, target temperature and real-time water flow of the gas water heater.

[0047] In this embodiment of the present invention, a gas water heater's water inlet pipe is equipped with a water inlet temperature sensor and a water flow sensor. The water inlet temperature sensor monitors the gas water heater's water inlet temperature in real time to obtain the real-time water inlet temperature, while the water flow sensor monitors the water flow rate in real time to obtain the real-time water flow rate. Based on the user's settings for the gas water heater, a target temperature is obtained; the target temperature is the user's desired water outlet temperature.

[0048] Step S102 , calculating the real-time theoretical current based on the real-time inlet water temperature, the target temperature and the real-time water flow.

[0049] In the embodiment of the present invention, the real-time theoretical current is determined based on theoretical calculations. Specifically, based on the real-time inlet water temperature, the target temperature, and the real-time water flow rate, the heat load that the gas water heater needs to provide in order to achieve the target outlet water temperature, i.e., the real-time theoretical load, can be determined. Based on the real-time theoretical load, a calculation is then performed to determine the current of the proportional valve required for the gas water heater to provide the real-time theoretical load, i.e., the real-time theoretical current.

[0050] Step S103 , when the gas water heater is in the temperature variable control stage, based on the change of the real-time predicted current output by the active disturbance rejection control algorithm of the gas water heater, the real-time compensation current of the gas water heater is calculated in real time.

[0051] In the embodiment of the present invention, the temperature variable control stage of the gas water heater refers to a change in the target load of the gas water heater, which is mainly caused by a change in the target temperature or water flow. For example, the user changes the target temperature, which causes the load required for the gas water heater to reach the target temperature to change.

[0052] In an embodiment of the present invention, when the gas water heater is in the variable temperature control stage, the real-time predicted current output by the active disturbance rejection control algorithm is statistically analyzed during a first calculation cycle to calculate a real-time compensation current. The real-time predicted current is the target current value of the proportional valve current calculated by estimating and compensating for disturbance changes in the gas water heater based on the active disturbance rejection control algorithm. The real-time predicted current is a positional parameter, meaning that the active disturbance rejection control algorithm outputs the current value to which the proportional valve current needs to be adjusted.

[0053] In one embodiment, the change in real-time predicted current during the variable temperature control stage can be used as real-time compensation current, thereby realizing statistics on the change in real-time predicted current during the variable temperature control stage. At this time, the first calculation cycle of the real-time compensation current is consistent with the duration of the variable temperature control stage.

[0054] In one embodiment, after the gas water heater is ignited, the active disturbance rejection control algorithm calculates the real-time predicted current in real time. That is, after the gas water heater is ignited and begins heating, the active disturbance rejection control algorithm continuously outputs the real-time predicted current, regardless of the state or control stage of the gas water heater, until the gas water heater is turned off.

[0055] It should be noted that, for example, in this embodiment, an active disturbance rejection control algorithm is used as the feedback control algorithm, but those skilled in the art know that the feedback control algorithm can also be other algorithms such as a PID control algorithm, and no specific limitation is made here.

[0056] Step S104 : in response to the gas water heater entering the constant temperature control stage, the most recently calculated real-time compensation current is used as the target compensation current.

[0057] In an embodiment of the present invention, the constant temperature control stage of the gas water heater refers to the stage of maintaining the outlet water temperature of the gas water heater near the target temperature; when the outlet water temperature of the gas water heater reaches the target temperature or is close to the target temperature, the gas water heater is controlled to enter the constant temperature control stage.

[0058] In an embodiment of the present invention, in response to the gas water heater entering the constant temperature control stage, the most recently calculated real-time compensation current is used as the target compensation current, that is, the real-time compensation current last calculated during the variable temperature control stage is used as the target compensation current. The target compensation current can represent the overall change in the real-time predicted current during the variable temperature control stage. Therefore, when calculating the target control current of the gas water heater, the real-time predicted current can be calculated based on the overall change in the real-time predicted current during the variable temperature control stage, thereby converting the position-based real-time predicted current into an incremental parameter.

[0059] Step S105, when the gas water heater is in the constant temperature control stage, the target control current of the gas water heater is calculated in real time based on the target compensation current, the real-time predicted current and the real-time theoretical current, and the proportional valve current of the gas water heater is adjusted based on the target control current.

[0060] In an embodiment of the present invention, when the gas water heater is in the constant temperature control stage, the target control current of the gas water heater is calculated in real time based on the target compensation current, the real-time predicted current and the real-time theoretical current. On the one hand, the position-based real-time predicted current is converted into an incremental parameter through the target compensation current. On the other hand, the real-time predicted current is combined with the real-time theoretical current to realize parallel control of the gas water heater by theoretical calculation and feedback control, thereby improving the response speed while avoiding the problem of incoordination of control signal superposition and ensuring control stability.

[0061] In the embodiment of the present invention, after the target control current is calculated, the proportional valve current of the gas water heater is adjusted to the target control current, thereby achieving control of the gas water heater in the constant temperature control stage.

[0062] In one embodiment, Figure 2 This is a flow chart of calculating the real-time theoretical current in the control method of the gas water heater according to an embodiment of the present invention, as shown in FIG. Figure 2 As shown, the above step S102, which calculates the real-time theoretical current based on the real-time inlet water temperature, the target temperature and the real-time water flow, may include the following steps:

[0063] Step S201 : determining the real-time theoretical load based on the real-time inlet water temperature, the target temperature and the real-time water flow rate.

[0064] In the embodiment of the present invention, the real-time theoretical load is determined based on the real-time inlet water temperature, the target temperature and the real-time water flow rate, which can be shown in the following formula (1):

[0065] P=(T s -T i )×Q formula (1)

[0066] Among them, P is the real-time theoretical load, T s is the target temperature, T i is the real-time inlet water temperature, T i The real-time water flow.

[0067] Step S202: Determine the real-time theoretical current based on the real-time theoretical load.

[0068] In the embodiment of the present invention, the gas flow required to meet the real-time theoretical current load of the gas water heater can be determined based on the gas calorific value and gas efficiency, and then the real-time theoretical current can be determined based on the mapping relationship between the gas flow and the proportional valve current.

[0069] In one embodiment, in the above step S103, the real-time compensation current can be calculated in real time by the following formula (2):

[0070]

[0071] in, is the real-time compensation current currently calculated, is the real-time compensation current calculated last time, The real-time predicted current output by the active disturbance rejection control algorithm is It is the real-time predicted current of the last output of the active disturbance rejection control algorithm.

[0072] In one embodiment, after the gas water heater is ignited, the real-time predicted current and the real-time theoretical current are calculated according to the second calculation cycle, thereby aligning the time quantities of the real-time predicted current and the real-time theoretical current, and avoiding the situation where the phase inconsistency between the two signals occurs when combining theoretical calculation and feedback control. The real-time compensation current being calculated for the first calculation cycle of the current period is: is the real-time compensation current calculated in the first calculation cycle before the current first calculation cycle; is the real-time predicted current output by the active disturbance rejection control algorithm in the most recent second calculation cycle, For The real-time predicted current output by the active disturbance rejection control algorithm in the second calculation cycle before .

[0073] In one embodiment, the period lengths of the first calculation period and the second calculation period can be set according to actual application requirements. The two can be set to the same period length or different period lengths, and no specific limitation is made here.

[0074] In one embodiment, the initial value of the real-time compensation current is zero, and the initial value of the real-time predicted current is zero. During the subsequent cyclic control process of the gas water heater, that is, after entering the variable temperature control stage for the first time, the process of cycling between the constant temperature control stage and the variable temperature control stage according to the real-time theoretical load and the change in the outlet water temperature of the gas water heater, when the gas water heater enters the variable temperature control stage, the real-time compensation current is calculated in real time based on the above formula, and the real-time predicted current is obtained based on the output of the active disturbance rejection control algorithm.

[0075] In one embodiment, when the gas water heater first enters the variable temperature control stage after ignition, the real-time predicted current value is set to the initial value. To prevent excessive target load fluctuations from causing inaccurate target compensation current, the real-time compensation current can be reset to the initial value each time the variable temperature control stage is entered. To ensure control continuity, the real-time compensation current value can be set to the initial value the first time the gas water heater first enters the variable temperature control stage after ignition.

[0076] According to the above formula (2), In fact, it is the inverse of the difference between the most recently output real-time predicted current and the real-time predicted current outputted the previous time, that is, the inverse of the change in the most recently real-time predicted current; accordingly, the real-time compensation current can represent the change in the most recently real-time predicted current minus the real-time compensation current calculated the previous time, that is, the difference between the real-time predicted current outputted when entering the variable temperature control stage and the real-time predicted current outputted the most recently, that is, the inverse of the change in the real-time predicted current from the last time the variable temperature control stage was entered to the current time. Thus, the change in the real-time predicted current in the variable temperature control stage can be accumulated through the real-time compensation current. When the gas water heater enters the constant temperature control stage from the variable temperature control stage, the real-time compensation current calculated the most recently is used as the target compensation current, and thus the inverse of the change in the real-time predicted current in the entire variable temperature control stage is used as the target compensation current.

[0077] In one embodiment, in the above step S105, the target control current can be calculated in real time using the following formula (3):

[0078]

[0079] Among them, I b To control the current, is the real-time theoretical current, To predict the current in real time, I s is the target compensation current.

[0080] According to the above formula (3), on the one hand, the real-time predicted current is added to the target compensation current, which can remove the changes in the real-time predicted current generated in the previous control stage, thereby converting the real-time predicted current into an incremental parameter; on the other hand, the real-time predicted current is added to the real-time theoretical current to realize the parallel control of the theoretical calculation and the feedback control algorithm, thereby using the theoretical calculation to determine the control benchmark, and using the incremental parameters of the feedback control algorithm to provide incremental correction, thereby performing dynamic disturbance compensation on the basis of the static benchmark of the theoretical calculation to ensure the stability of the control.

[0081] In the above embodiment, when the gas water heater is in the variable temperature control stage, the real-time theoretical current is used as the target control current, and the proportional valve current is adjusted based on the target control current, so that the operation of the gas water heater is controlled by theoretical calculation in the variable temperature control stage, thereby realizing rapid adjustment of the water outlet temperature of the gas water heater.

[0082] In the above embodiment, when the gas water heater is in the constant temperature control stage, if the change in the real-time theoretical load of the gas water heater reaches a preset change value, the gas water heater is controlled to enter the variable temperature control stage; or after the gas water heater is ignited, the gas water heater is controlled to enter the variable temperature control stage. In this way, the gas water heater can quickly respond to changes in operating conditions and enter the variable temperature control stage to quickly adjust the water outlet temperature of the gas water heater.

[0083] In the above embodiment, when the gas water heater is in the variable temperature control stage, if the combustion time of the gas water heater reaches a preset time, or the outlet water temperature of the gas water heater reaches a target temperature, the gas water heater is controlled to enter the constant temperature control stage. The preset time is an empirical value, which can be set to 10 seconds, or determined based on the heating conditions of the gas water heater during past operation.

[0084] A control method for a gas water heater provided by an embodiment of the present invention calculates a target control current of the gas water heater in real time based on a target compensation current, a real-time predicted current, and a real-time theoretical current when the gas water heater is in a constant temperature control stage, and adjusts the proportional valve current of the gas water heater based on the target control current. This method controls the gas water heater by combining theoretical calculation with a feedback control algorithm in parallel. When the load of the gas water heater changes, feedforward control can be performed promptly, thereby improving response speed and avoiding temperature overshoot. Simultaneously, a real-time compensation current of the gas water heater is calculated in real time based on changes in the real-time predicted current output by an active disturbance rejection control algorithm of the gas water heater. Changes in the predicted current during the variable temperature control stage are statistically analyzed. When the gas water heater enters the constant temperature control stage, the most recently calculated real-time compensation current is used as the target compensation current. The change in the real-time predicted current during the variable temperature control stage is used as the adjustment reference for the constant temperature control stage. When calculating the target control current, the real-time predicted current can be converted into an incremental output, thereby avoiding the problem of control signal superposition inconsistency between the real-time theoretical current and the real-time predicted current, thereby ensuring control stability.

[0085] According to an embodiment of the present invention, on the other hand, a gas water heater is provided, including: a controller, the controller being used for the control method of the gas water heater described in any of the above embodiments.

[0086] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] The specific contents of the above specific embodiments merely represent several embodiments of the present invention. Although the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present invention, and such modifications and improvements shall fall within the scope of protection of the present invention.

Claims

1. A method for controlling a gas water heater, characterized in that: The method comprises: Obtaining the real-time water inlet temperature, target temperature and real-time water flow of the gas water heater; Calculating a real-time theoretical current in real time based on the real-time inlet water temperature, the target temperature, and the real-time water flow rate; When the gas water heater is in the variable temperature control stage, based on the change of the real-time predicted current output by the active disturbance rejection control algorithm of the gas water heater, the real-time compensation current of the gas water heater is calculated in real time; In response to the gas water heater entering a constant temperature control stage, using the most recently calculated real-time compensation current as a target compensation current; When the gas water heater is in the constant temperature control stage, the target control current of the gas water heater is calculated in real time based on the target compensation current, the real-time predicted current and the real-time theoretical current, and the proportional valve current of the gas water heater is adjusted based on the target control current.

2. The method according to claim 1, characterized in that The real-time prediction of current changes based on the output of the active disturbance rejection control algorithm and the real-time calculation of the real-time compensation current include: in, is the real-time compensation current currently calculated, is the real-time compensation current calculated last time, is the real-time predicted current output by the active disturbance rejection control algorithm. It is the real-time predicted current outputted by the active disturbance rejection control algorithm last time.

3. The method according to claim 2, characterized in that The initial value of the real-time compensation current is zero, and the initial value of the real-time prediction current is zero.

4. The method according to claim 1, wherein The step of calculating the target control current of the gas water heater in real time based on the target compensation current, the real-time predicted current, and the real-time theoretical current includes: Among them, I b for the target control current, is the real-time theoretical current, is the real-time predicted current, I s A current is compensated for the target.

5. The method according to claim 1, wherein The real-time calculation of the real-time theoretical current based on the real-time inlet water temperature, the target temperature and the real-time water flow rate includes: determining a real-time theoretical load based on the real-time inlet water temperature, the target temperature, and the real-time water flow rate; The real-time theoretical current is determined based on the real-time theoretical load.

6. The method according to claim 1, characterized in that The method further comprises: After the gas water heater is ignited, the real-time predicted current is calculated in real time based on the active disturbance rejection control algorithm.

7. The method according to claim 1, characterized in that The method further comprises: When the gas water heater is in the temperature-variable control stage, the real-time theoretical current is used as the target control current, and the proportional valve current is adjusted based on the target control current.

8. The method according to claim 1, characterized in that The method further comprises: When the gas water heater is in the constant temperature control stage, if the change of the real-time theoretical load of the gas water heater reaches a preset change value, the gas water heater is controlled to enter the variable temperature control stage; Alternatively, after the gas water heater is ignited, the gas water heater is controlled to enter a temperature variable control stage.

9. The method according to claim 1, characterized in that The method further comprises: When the gas water heater is in the variable temperature control stage, if the combustion time of the gas water heater reaches the preset time, or the outlet water temperature of the gas water heater reaches the target temperature, the gas water heater is controlled to enter the constant temperature control stage.

10. A gas water heater, characterized in that: include: A controller, wherein the controller is used to execute the control method of the gas water heater according to any one of claims 1 to 9.

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