Direct-current fan control method and device of water heater and water heater

Abstract

The invention relates to the technical field of water heater control, and discloses a direct-current fan control method and device of a water heater and the water heater. The first number of times that the level state of the MOS tube is overturned when the direct current fan of the water heater is driven by adopting the first control logic in the PWM carrier wave period is smaller than the second number of times that the level state of the MOS tube is overturned when the direct current fan of the water heater is driven by adopting the second control logic in the PWM carrier wave period; the method comprises the steps that when the water heater is in a working state, a first control logic or a second control logic is selected to control a direct-current fan of the water heater based on the current combustion load of the water heater. The control logic suitable for the current combustion load is flexibly selected in time according to the current combustion load of the water heater, so that the turnover frequency of the direct-current fan of the water heater is adjusted, and the heating value of an MOS tube for driving the direct-current fan when the direct-current fan runs in a high-speed state and low-frequency resonance noise generated when the direct-current fan runs in a low-frequency mode are remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of water heater control, and in particular to a direct current fan control method and device for a water heater and a water heater. Background Art

[0002] The drive control of the DC fan of the gas water heater is mostly implemented by the single resistor FOC (Field-Oriented Control) control algorithm. When the gas water heater is running under different combustion loads, the DC fan outputs different speeds through the SVPWM (Space Vector Pulse Width Modulation) drive method to ensure that the exhaust gas of the water heater meets the standard requirements. Among them, the single resistor sampling FOC control method requires two samplings in one SVPWM cycle.

[0003] In the related art, the modulation modes adopted by the DC fan of the gas water heater through FOC control mainly include seven-segment SVPWM and five-segment SVPWM. Seven-segment SVPWM means that the level state of the MOS tube driving the fan is flipped seven times in one PWM carrier cycle, and five-segment SVPWM means that the level state of the MOS tube driving the fan is flipped five times in one PWM carrier cycle. When designing products, R&D personnel generally choose one of them as the modulation mode adopted by FOC control.

[0004] However, both of the above two modulation methods have certain defects. In the modulation method with a large number of flips, when the DC fan runs at a high speed, the MOS tube it drives generates a lot of heat and radiates a lot. In the modulation method with a small number of flips, when the DC fan runs at a low speed, it is easy to generate low-frequency resonance noise. Therefore, the existing control method cannot adapt well to all working conditions of the gas water heater. Summary of the invention

[0006] In view of this, the present invention provides a DC fan control method, device and water heater for a gas water heater, so as to solve the problem that when the DC fan of the gas water heater adopts a modulation method with a large number of flipping times, the DC fan runs at a high speed, and the MOS tube driven by it generates a large amount of heat and radiates a large amount of radiation outward; and when the DC fan adopts a modulation method with a small number of flipping times, the DC fan runs at a low speed, and it is easy to generate low-frequency resonance noise.

[0007] In a first aspect, the present invention provides a method for controlling a DC fan of a water heater, wherein the water heater is preset with a first control logic and a second control logic, and a first number of times that a MOS tube level state flips when the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle is less than a second number of times that a MOS tube level state flips when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle; the method comprises:

[0008] When the water heater is in working state, based on the current combustion load of the water heater, the first control logic or the second control logic is selected to control the DC fan of the water heater, wherein when the current combustion load is in the low load segment, the second control logic is used to control the DC fan of the water heater, and when the current combustion load is not in the low load segment, the first control logic is used to control the DC fan of the water heater.

[0009] The DC fan control method of the water heater of the embodiment of the present invention, when the water heater is in working state, based on the current combustion load of the water heater, after the current combustion load changes, selects the first control logic or the second control logic to control the DC fan of the water heater, and the number of MOS tube level state flips is different when different control logics are used to drive the DC fan of the water heater in the PWM carrier cycle. Therefore, according to the current combustion load of the water heater, the control logic adapted to the current combustion load is flexibly selected in time, and then the number of flips of the DC fan of the water heater is adjusted, effectively avoiding the DC fan still using a modulation method with a large number of flips when running at a high speed, thereby significantly reducing the heat generated by the MOS tube driving the DC fan, and effectively avoiding the DC fan still using a modulation method with large outward radiation and a small number of flips when running at a low speed, thereby significantly reducing the low-frequency resonance noise generated when the DC fan runs at a low frequency.

[0010] In an optional implementation, based on the current combustion load of the water heater, selecting the first control logic or the second control logic to control the DC fan of the water heater includes:

[0011] Based on the current combustion load, determining the current duty cycle of the DC fan;

[0012] According to the current duty cycle, the first control logic or the second control logic is selected to control the DC fan of the water heater.

[0013] The DC fan control method of the water heater of the embodiment of the present invention determines the current duty cycle of the DC fan based on the current combustion load, and selects the first control logic or the second control logic to control the DC fan of the water heater according to the current duty cycle. Here, the current duty cycle closely related to the key parameters of the control logic is selected as a reference, and the first control logic or the second control logic is selected according to the current duty cycle. The situation where the current duty cycle of the DC fan does not match the control logic of the DC fan is effectively avoided, thereby significantly avoiding the sampling missing and noise problems caused by the inappropriate sampling interval length.

[0014] In an optional implementation, according to the current duty cycle, selecting the first control logic or the second control logic to control the DC fan of the water heater includes:

[0015] When the current duty cycle is greater than or equal to the first preset duty cycle, selecting the first control logic to control the DC fan;

[0016] When the current duty cycle is less than the first preset duty cycle, the second control logic is selected to control the DC fan.

[0017] The DC fan control method of the water heater of the embodiment of the present invention, when the current duty cycle is greater than or equal to the first preset duty cycle, selects the first control logic with fewer MOS tube level state flip times to control the DC fan, effectively ensuring a sufficiently long sampling interval of the DC fan, thereby effectively ensuring the sinusoidal nature of the DC fan drive waveform, and at the same time ensuring that the temperature rise of the MOS tube meets the requirements in the medium and high load sections. When the current duty cycle is less than the first preset duty cycle, selects the second control logic with more MOS tube level state flip times to control the DC fan, effectively ensuring the length of the sampling interval while ensuring the sinusoidal nature of the drive waveform, thereby significantly reducing the low-frequency noise of the DC fan operation.

[0018] In an optional implementation, based on the current combustion load, selecting the first control logic or the second control logic to control the DC fan of the water heater includes:

[0019] When the current duty cycle increases to a second preset duty cycle, selecting the first control logic to control the DC fan;

[0020] When the current duty cycle drops to a third preset duty cycle, selecting the second control logic to control the DC fan;

[0021] When the current duty cycle is less than the second preset duty cycle and the current duty cycle is greater than the third preset duty cycle, keep using the current control logic to control the DC fan;

[0022] The second preset duty cycle is greater than the third preset duty cycle.

[0023] The DC fan control method of the water heater of the embodiment of the present invention sets the threshold value of the current duty cycle rising and the threshold value of the current duty cycle falling, and when the current duty cycle is less than the second preset duty cycle and the current duty cycle is greater than the third preset duty cycle, the current control logic is kept to control the DC fan. Thus, the control logic of the DC fan is switched only when the current duty cycle rises or falls to a certain extent, effectively avoiding frequent switching of the control logic of the DC fan, thereby significantly improving the stability of the water heater control.

[0024] In an optional implementation, before selecting the first control logic or the second control logic to control the DC fan of the water heater based on the current combustion load of the water heater, the method further includes:

[0025] Get the model, gas type and capacity of the water heater;

[0026] According to the machine model, gas type and capacity, the duty cycle threshold of the DC fan for selecting the first control logic or the second control logic is determined.

[0027] The DC fan control method of the water heater in the embodiment of the present invention pre-sets the control logic corresponding to the water heater model, gas type and capacity, and when the water heater is first operated, determines the duty cycle threshold of the DC fan for selecting the first control logic or the second control logic based on the water heater model, gas type and capacity, thereby effectively improving the accuracy of selecting the DC fan control logic, significantly reducing the probability of generating low-frequency noise, and effectively improving the user experience.

[0028] In an optional implementation, determining a duty cycle threshold of a DC fan that selects the first control logic or the second control logic according to the machine model, gas type, and capacity includes:

[0029] Selecting a duty cycle threshold of the DC fan corresponding to the model, gas type and capacity from the first mapping;

[0030] The first mapping is used to characterize the correspondence between multiple machine models, multiple gas types, multiple capacities and multiple DC fan duty cycle thresholds.

[0031] In an optional embodiment, the machine type includes at least one of a strong suction type and a strong drum type;

[0032] The gas type includes at least one of natural gas, liquefied gas, and artificial gas.

[0033] In an optional implementation, the first number is 5 and the second number is 7.

[0034] In a second aspect, the present invention provides a DC fan control device for a water heater, wherein the water heater is preset with a first control logic and a second control logic, and a first number of times that the MOS tube level state is flipped when the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle is less than a second number of times that the MOS tube level state is flipped when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle; the device comprises:

[0035] A load acquisition module, used to obtain the current combustion load of the water heater;

[0036] The control module is used to select the first control logic or the second control logic to control the DC fan of the water heater based on the current combustion load.

[0037] In a third aspect, the present invention provides a water heater, comprising:

[0038] DC fan;

[0039] The main controller of the water heater is used to collect the current combustion load of the water heater;

[0040] The fan drive controller is connected to the DC fan and the main controller, and is used to execute the DC fan control method of the water heater according to the first aspect or any corresponding embodiment thereof to control the DC fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 is a flow chart of a DC fan control method for a water heater according to an embodiment of the present invention;

[0043] Figure 2 is a flow chart of another DC fan control method for a water heater according to an embodiment of the present invention;

[0044] Figure 3 is a flow chart of a DC fan control method for another water heater according to an embodiment of the present invention;

[0045] Figure 4 is a structural block diagram of a DC fan control device for a water heater according to an embodiment of the present invention;

[0046] Figure 5 is a structural block diagram of a water heater according to an embodiment of the present invention;

[0047] Figure 6 It is a schematic diagram of the hardware structure of the fan drive controller of the water heater according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0049] Due to the DC fan structure of the gas water heater and the installation position of the DC fan on the water heater, when the gas water heater is running, a large amount of wind rushes in from the air inlet on the back of the gas water heater, part of which is sucked into the DC fan, and part of the wind will hit the body of the DC fan. When the gas water heater is running at a low load, the suction force of the fan is small, and more wind is not sucked into the DC fan. At this time, when the frequency of the impact on the DC fan is similar to the vibration frequency of the DC fan when it is running, low-frequency noise is generated. According to an embodiment of the present invention, a DC fan control method embodiment of a water heater is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0050] In the present embodiment, a DC fan control method for a water heater is provided, which can be used for controlling the above-mentioned water heater. The water heater is preset with a first control logic and a second control logic. When the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle, the first number of times the MOS tube level state is flipped is less than the second number of times the MOS tube level state is flipped when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle.

[0051] Figure 1 is a flow chart of a DC fan control method for a water heater according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0052] Step S101, when the water heater is in working state, based on the current combustion load of the water heater, select the first control logic or the second control logic to control the DC fan of the water heater.

[0053] In an optional embodiment of the present invention, the combustion load of the water heater can be obtained by the model specifications of the water heater or estimated by measuring the gas consumption in actual use. For example, the real-time combustion load of the gas water heater can be determined by parameters such as the fuel consumption of the gas water heater, and the parameters such as the fuel consumption can be obtained in real time.

[0054] In an optional implementation, the lower the combustion load of the gas water heater, the lower the speed of the DC fan of the gas water heater. At this time, the SVPWM (Space Vector Pulse Width Modulation) of the water heater is short. However, if FOC control with single resistor sampling is adopted, it is necessary to perform two samplings in one SVPWM cycle. In order to ensure that one SVPWM cycle has enough time to perform two samplings in the FOC control process, when the current combustion load of the water heater is low, the first control logic with a smaller number of MOS tube level state flips when driving the DC fan of the water heater in the PWM carrier cycle can be selected. In this way, the number of level state flips of the MOS tube of the DC fan of the water heater driven in the PWM carrier cycle is small, and the interval time between each two flips can be used as an SVPWM cycle, so that one SVPWM cycle of the FOC control process is sufficient to perform two samplings. As for the judgment standard of the current low combustion load of the water heater, it can be set according to actual needs. Similarly, the first number of times the level state of the MOS tube of the DC fan of the water heater is flipped by the first control logic and the second number of times the level state of the MOS tube of the DC fan of the water heater is flipped in the second control logic can also be set according to actual needs, and the present invention does not make specific limitations on this.

[0055] In an optional implementation, the first number is 5 and the second number is 7.

[0056] The DC fan control method of the water heater of the embodiment of the present invention obtains the current combustion load of the water heater, and based on the current combustion load, after the current combustion load changes, selects the first control logic or the second control logic to control the DC fan of the water heater, and the number of MOS tube level state flips is different when different control logics are used to drive the DC fan of the water heater in the PWM carrier cycle. Therefore, according to the current combustion load of the water heater, the control logic adapted to the current combustion load is flexibly selected in time, and the number of flips of the DC fan of the water heater is adjusted, effectively avoiding the DC fan still using a modulation method with a large number of flips when running at a high speed, thereby significantly reducing the heat generated by the MOS tube driving the DC fan, and effectively avoiding the DC fan still using a modulation method with large outward radiation and a small number of flips when running at a low speed, thereby significantly reducing the low-frequency resonance noise generated when the DC fan runs at a low frequency.

[0057] In the present embodiment, a DC fan control method for a water heater is provided, which can be used for controlling the above-mentioned water heater. The water heater is preset with a first control logic and a second control logic. When the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle, the first number of times the MOS tube level state is flipped is less than the second number of times the MOS tube level state is flipped when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle.

[0058] Figure 2 is a flow chart of a DC fan control method for a water heater according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0059] Step S201, when the water heater is in working state, based on the current combustion load of the water heater, select the first control logic or the second control logic to control the DC fan of the water heater, wherein when the current combustion load is in the low load segment, the second control logic is used to control the DC fan of the water heater, and when the current combustion load is not in the low load segment, the first control logic is used to control the DC fan of the water heater.

[0060] Specifically, step S201 may include:

[0061] Step S2011, determining the current duty cycle of the DC fan based on the current combustion load.

[0062] Step S2012: Select the first control logic or the second control logic to control the DC fan of the water heater according to the current duty cycle.

[0063] In an optional implementation, step S2012 may include:

[0064] Step a1: when the current duty cycle is greater than or equal to the first preset duty cycle, select the first control logic to control the DC fan.

[0065] For example, the first preset duty cycle may be 25%.

[0066] Step a2: when the current duty cycle is less than the first preset duty cycle, select the second control logic to control the DC fan.

[0067] The DC fan control method of the water heater of the embodiment of the present invention, when the current duty cycle is greater than or equal to the first preset duty cycle, selects the first control logic with fewer MOS tube level state flip times to control the DC fan, effectively ensuring a sufficiently long sampling interval of the DC fan, thereby effectively ensuring the sinusoidal nature of the DC fan drive waveform, and at the same time ensuring that the temperature rise of the MOS tube meets the requirements in the medium and high load sections. When the current duty cycle is less than the first preset duty cycle, selects the second control logic with more MOS tube level state flip times to control the DC fan, effectively ensuring the length of the sampling interval while ensuring the sinusoidal nature of the drive waveform, thereby significantly reducing the low-frequency noise of the DC fan operation.

[0068] In another optional implementation, step S2012 may include:

[0069] Step b1, when the current duty cycle increases to a second preset duty cycle, select the first control logic to control the DC fan.

[0070] Step b2: when the current duty cycle drops to a third preset duty cycle, select the second control logic to control the DC fan.

[0071] Step b3, when the current duty cycle is less than the second preset duty cycle and the current duty cycle is greater than the third preset duty cycle, keep using the current control logic to control the DC fan, wherein the second preset duty cycle is greater than the third preset duty cycle.

[0072] For example, the second preset duty cycle may be 20%, and the third preset duty cycle may be 30%.

[0073] The DC fan control method of the water heater of the embodiment of the present invention sets the threshold value of the current duty cycle rising and the threshold value of the current duty cycle falling. When the current duty cycle is less than the second preset duty cycle and the current duty cycle is greater than the third preset duty cycle, the current control logic is maintained to control the DC fan. Thus, the control logic of the DC fan is switched only when the current duty cycle rises or falls to a certain extent, effectively avoiding frequent switching of the control logic of the DC fan, thereby significantly improving the stability of the water heater control. It is worth noting that if the current duty cycle is less than the second preset duty cycle and the current duty cycle is greater than the third preset duty cycle when the gas water heater is just started, the second control logic is adopted.

[0074] The DC fan control method of the water heater of the embodiment of the present invention determines the current duty cycle of the DC fan based on the current combustion load, and selects the first control logic or the second control logic to control the DC fan of the water heater according to the current duty cycle. Here, the current duty cycle closely related to the key parameters of the control logic is selected as a reference, and the first control logic or the second control logic is selected according to the current duty cycle. The situation where the current duty cycle of the DC fan does not match the control logic of the DC fan is effectively avoided, thereby significantly avoiding the sampling missing and noise problems caused by the inappropriate sampling interval length.

[0075] In the present embodiment, a DC fan control method for a water heater is provided, which can be used for controlling the above-mentioned water heater. The water heater is preset with a first control logic and a second control logic. When the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle, the first number of times the MOS tube level state is flipped is less than the second number of times the MOS tube level state is flipped when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle. Figure 3 is a flow chart of a DC fan control method for a water heater according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0076] Step S301, obtaining the model, gas type and capacity of the water heater.

[0077] In an optional embodiment, the water heater may include a strong extraction type and a strong drum type, etc. The gas type of the water heater may include natural gas, liquefied gas, and artificial gas, etc. The capacity of the water heater may include 16L and 32L, etc.

[0078] When the water heater is operated for the first time, the water heater model, gas type and capacity parameters can be directly obtained. The model, gas type and capacity can also be selected through the water heater display, and the selected model, gas type and capacity parameters are sent to the DC fan drive controller through the PWM control port of the water heater main controller.

[0079] In an optional embodiment, after obtaining parameters such as the water heater model, gas type, and capacity when the water heater is run for the first time, the above parameters can be directly stored until new parameters such as the water heater model, gas type, and capacity are received, and then the parameters such as the water heater model, gas type, and capacity are updated.

[0080] In another optional implementation, the water heater may obtain parameters such as the model, gas type, and capacity of the water heater each time the water heater is run.

[0081] Step S302, determining a duty cycle threshold of the DC fan for selecting the first control logic or the second control logic according to the model, gas type and capacity.

[0082] Specifically, the duty cycle threshold of the DC fan of the first control logic or the second control logic can be determined in advance through experiments and experience for water heaters of different models, gas types and capacities, and a first mapping can be generated to characterize the correspondence between multiple models, multiple gas types and multiple capacities and the duty cycle thresholds of multiple DC fans.

[0083] In an optional implementation, a duty cycle threshold value of a DC fan corresponding to the machine type, gas type and capacity may be selected from the first mapping. The first mapping is used to characterize the correspondence between multiple machine types, multiple gas types and multiple capacities and the duty cycle threshold values ​​of multiple DC fans. The drive controller of the DC fan may select the duty cycle threshold value of the DC fan corresponding to the machine type, gas type and capacity from the first mapping through the parameters obtained in step S201.

[0084] Table 1 is an exemplary description of the first mapping. As shown in Table 1, when the water heater is a forced extraction type, the gas type is natural gas, and the capacity is less than 16L, the duty cycle threshold of the DC fan of the first control logic or the second control logic is A1. Specifically, A1 can be the threshold of the duty cycle (PWM value) of the DC fan.

[0085] Table 1 Exemplary description of the first mapping

[0086]

[0087] Wherein, A1 can be a certain value, for example: 25%. If the current duty cycle of the DC fan determined according to the current combustion load of the water heater is less than 25%, the DC fan of the water heater with the first control logic is selected. If the current duty cycle of the DC fan determined according to the current combustion load of the water heater is greater than or equal to 25%, the DC fan of the water heater with the second control logic is selected.

[0088] A1 can also be an interval range. For example: 20% to 30%, when the current duty cycle of the DC fan determined according to the current combustion load of the water heater rises to 30%, the first control logic is selected to control the DC fan, and when the current duty cycle of the DC fan determined according to the current combustion load of the water heater drops to 20%, the second control logic is selected to control the DC fan.

[0089] Similarly, A2-A4, B1-B4 and C1-C4 can all be set to a value or a range according to actual needs.

[0090] The DC fan control method of the water heater in the embodiment of the present invention pre-sets the control logic corresponding to the water heater model, gas type and capacity, and when the water heater is first operated, determines the duty cycle threshold of the DC fan for selecting the first control logic or the second control logic based on the water heater model, gas type and capacity, thereby effectively improving the accuracy of selecting the DC fan control logic, significantly reducing the probability of generating low-frequency noise, and effectively improving the user experience.

[0091] Step S303, when the water heater is in working state, based on the current combustion load of the water heater, select the first control logic or the second control logic to control the DC fan of the water heater, wherein when the current combustion load is in the low load segment, the second control logic is used to control the DC fan of the water heater, and when the current combustion load is not in the low load segment, the first control logic is used to control the DC fan of the water heater.

[0092] For details, please see Figure 1 Step S101 of the illustrated embodiment and Figure 2 Step S201 of the illustrated embodiment will not be described in detail here.

[0093] In this embodiment, a DC fan control device for a water heater is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made are not repeated here. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0094] The present invention provides a DC fan control device for a water heater, wherein the water heater is preset with a first control logic and a second control logic, and when the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle, the first number of times the MOS tube level state is flipped is less than the second number of times the MOS tube level state is flipped when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle. Figure 4 As shown, the DC fan control device of the water heater includes:

[0095] The control module 401 is used to select the first control logic or the second control logic to control the DC fan of the water heater based on the current combustion load when the water heater is in working state, wherein when the current combustion load is in the low load segment, the second control logic is used to control the DC fan of the water heater, and when the current combustion load is not in the low load segment, the first control logic is used to control the DC fan of the water heater.

[0096] In an optional implementation, the control module 401 includes:

[0097] A duty cycle unit, for determining a current duty cycle of the DC fan based on a current combustion load;

[0098] The selection unit is used to select the first control logic or the second control logic to control the DC fan of the water heater according to the current duty cycle.

[0099] In an optional implementation, the selection unit includes:

[0100] A first selection subunit, configured to select a first control logic to control the DC fan when the current duty cycle is greater than or equal to a first preset duty cycle;

[0101] The second selection subunit is used to select the second control logic to control the DC fan when the current duty cycle is less than the first preset duty cycle.

[0102] In an optional implementation, based on the current combustion load, selecting the first control logic or the second control logic to control the DC fan of the water heater includes:

[0103] An increasing selection subunit, used for selecting the first control logic to control the DC fan when the current duty cycle increases to a second preset duty cycle;

[0104] A descending selection subunit, used for selecting the second control logic to control the DC fan when the current duty cycle decreases to a third preset duty cycle;

[0105] A maintaining subunit, used for maintaining the use of the current control logic to control the DC fan when the current duty cycle is less than the second preset duty cycle and the current duty cycle is greater than the third preset duty cycle;

[0106] The second preset duty cycle is greater than the third preset duty cycle.

[0107] In an optional implementation, the DC fan control device of the water heater further includes:

[0108] A parameter acquisition module is used to obtain the model, gas type and capacity of the water heater before obtaining the current combustion load of the water heater;

[0109] The determination condition module is used to determine the duty cycle threshold of the DC fan that selects the first control logic or the second control logic according to the machine model, gas type and capacity.

[0110] In an optional implementation, the determination condition module includes:

[0111] A condition determination unit, configured to select a duty cycle threshold of the DC fan corresponding to the model, gas type and capacity from the first mapping;

[0112] The first mapping is used to characterize the correspondence between multiple machine models, multiple gas types, multiple capacities and multiple DC fan duty cycle thresholds.

[0113] In an optional embodiment, the machine type includes at least one of a strong suction type and a strong drum type;

[0114] The gas type includes at least one of natural gas, liquefied gas, and artificial gas.

[0115] In an optional implementation, the first number is 5 and the second number is 7.

[0116] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0117] The DC fan control device of the water heater in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit), a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0118] The embodiment of the present invention also provides a water heater, such as Figure 5 As shown, the water heater comprises:

[0119] DC fan 501;

[0120] The main controller 502 of the water heater is used to collect the current combustion load of the water heater;

[0121] The fan drive controller 503 is connected to the DC fan 501 and the main controller 502, and is used to execute the DC fan control method of the water heater according to the first aspect or any corresponding embodiment thereof to control the DC fan.

[0122] The fan drive controller 503 has the above Figure 4 The DC fan control device of the water heater shown.

[0123] See also Figure 6 , Figure 6 is a schematic diagram of the structure of a fan drive controller provided by an optional embodiment of the present invention, such as Figure 6As shown, the fan drive controller includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed in the fan drive controller, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple fan drive controllers can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 6 A processor 10 is taken as an example.

[0124] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0125] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0126] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required by at least one function; the data storage area may store data created according to the use of the fan drive controller, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the fan drive controller via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0127] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0128] The fan drive controller further comprises a communication interface 30 for the fan drive controller to communicate with other devices or a communication network.

[0129] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0130] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0131] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A DC fan control method for a water heater, characterized in that: The water heater is preset with a first control logic and a second control logic, and a first number of times the MOS tube level state flips when the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle is less than a second number of times the MOS tube level state flips when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle; the method comprises: When the water heater is in working state, based on the current combustion load of the water heater, the first control logic or the second control logic is selected to control the DC fan of the water heater, wherein when the current combustion load is in a low load segment, the second control logic is used to control the DC fan of the water heater; when the current combustion load is not in a low load segment, the first control logic is used to control the DC fan of the water heater.

2. The method according to claim 1, characterized in that: The selecting the first control logic or the second control logic to control the DC fan of the water heater based on the current combustion load of the water heater comprises: determining a current duty cycle of the DC fan based on the current combustion load; According to the current duty cycle, the first control logic or the second control logic is selected to control the DC fan of the water heater.

3. The method according to claim 2, characterized in that The method of selecting the first control logic or the second control logic to control the DC fan of the water heater according to the current duty cycle includes: When the current duty cycle is greater than or equal to a first preset duty cycle, selecting the first control logic to control the DC fan; When the current duty cycle is less than a first preset duty cycle, the second control logic is selected to control the DC fan.

4. The method according to claim 2, characterized in that: The selecting the first control logic or the second control logic to control the DC fan of the water heater based on the current combustion load includes: When the current duty cycle increases to a second preset duty cycle, selecting the first control logic to control the DC fan; When the current duty cycle drops to a third preset duty cycle, selecting the second control logic to control the DC fan; When the current duty cycle is less than the second preset duty cycle and the current duty cycle is greater than the third preset duty cycle, keep using the current control logic to control the DC fan; Wherein, the second preset duty cycle is greater than the third preset duty cycle.

5. The method according to claim 3, characterized in that: Before selecting the first control logic or the second control logic to control the DC fan of the water heater based on the current combustion load of the water heater, the method further includes: Obtain the model, gas type and capacity of the water heater; A duty cycle threshold of the DC fan for selecting the first control logic or the second control logic is determined according to the machine model, the gas type and the capacity.

6. The method according to claim 5, characterized in that The step of determining a duty cycle threshold of a DC fan for selecting the first control logic or the second control logic according to the machine model, the gas type, and the capacity includes: Selecting a duty cycle threshold of the DC fan corresponding to the machine type, the gas type and the capacity from the first mapping; The first mapping is used to characterize the correspondence between multiple machine models, multiple gas types and multiple capacities and the duty cycle thresholds of multiple DC fans.

7. The method according to claim 5 or 6, characterized in that: The machine type includes at least one of a strong pumping type and a strong drum type; The gas type includes at least one of natural gas, liquefied gas, and artificial gas.

8. The method according to any one of claims 1 to 6, characterized in that The first number is 5, and the second number is 7.

9. A DC fan control device for a water heater, characterized in that: The water heater is preset with a first control logic and a second control logic, and a first number of times the MOS tube level state flips when the first control logic is used to drive the DC fan of the water heater in a PWM carrier cycle is less than a second number of times the MOS tube level state flips when the second control logic is used to drive the DC fan of the water heater in a PWM carrier cycle; the device comprises: A load acquisition module, used to acquire the current combustion load of the water heater; A control module is used to select the first control logic or the second control logic to control the DC fan of the water heater based on the current combustion load.

10. A water heater, characterized in that: The water heater comprises: DC fan; The main controller of the water heater is used to collect the current combustion load of the water heater; A fan drive controller is connected to the DC fan and the main controller, and is used to execute the DC fan control method for the water heater according to any one of claims 1 to 8 to control the DC fan.

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