A method for controlling a heating element and a household appliance

Abstract

The present invention discloses a method for controlling a heating element and a household appliance. The method comprises: periodically detecting whether the supply voltage of the heating element crosses zero; and upon detecting that the supply voltage crosses zero, starting or stopping the heating operation of the heating element. The technical solution provided by the present invention aims to address the technical problem of short service life of relays in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of electrical equipment, and in particular to a control method for a heating element and a household electrical appliance. Background Art

[0002] Thermistors are a type of sensitive component, classified according to their temperature coefficient into positive temperature coefficient thermistors (PTC thermistors) and negative temperature coefficient thermistors (NTC thermistors). Thermistors are typically temperature-sensitive and exhibit varying resistance values ​​at different temperatures. PTC thermistors have a higher resistance at higher temperatures, while NTC thermistors have a lower resistance at higher temperatures. Both are semiconductor devices.

[0003] The PTC electric heating unit is a temperature-sensitive semiconductor resistor. When the temperature exceeds a certain level (eg, Curie temperature), the resistance value thereof increases in a stepwise manner as the temperature increases. The higher the temperature, the greater the resistance value.

[0004] To improve the heating capacity of air conditioners, electric auxiliary heating is typically added to the indoor unit. This allows for increased heating capacity even when the outdoor ambient temperature is low or the air conditioner's compressor heating capacity is low. Common electric auxiliary heating methods for air conditioners include metal tubular electric heating units, metal PTC electric heating units, and ceramic PTC electric heating units. Due to the self-limiting temperature of ceramic PTC electric heating units, even in extreme windless conditions, the surface temperature of the ceramic PTC electric heating unit remains low, typically below 260°C. In contrast, in windless conditions, the surface temperature of metal tubular electric heating units and metal PTC electric heating units exceeds 400°C. Therefore, ceramic PTC electric heating is much safer and is widely used in air conditioners.

[0005] The start and stop of ceramic PTC electric heating is controlled by a relay in the prior art. In practical applications, the use loss of the relay is large, which has a strong impact on the service life of the relay. Summary of the Invention

[0006] The main purpose of the present invention is to provide a control method for a heating element and a household appliance, so as to solve the problem of short service life of relays in the prior art.

[0007] To achieve the above object, the present invention provides a method for controlling a heating element, comprising:

[0008] Periodically check whether the power supply voltage value of the heating element passes through zero;

[0009] It is determined that the supply voltage value crosses the zero point, and the heating operation of the heating element is started or stopped.

[0010] Preferably, the method further comprises:

[0011] After starting the heating operation of the heating element, detecting the power value of the heating element after heating;

[0012] If the power value after heating is less than the preset first power value, stopping the heating operation of the heating element is not allowed.

[0013] Preferably, after stopping the heating operation of the heating element, the method further comprises:

[0014] detecting a power value of the heating element after releasing heat;

[0015] If the power value after heat release is less than the preset second power value, the heating operation of the heating element is not allowed to be started.

[0016] Preferably, the method further comprises:

[0017] Periodically obtain the actual temperature value of the environment to be measured;

[0018] At least one of the first power value and the second power value is adjusted according to the actual temperature value and a preset target temperature value.

[0019] Preferably, the starting or stopping of the heating operation of the heating element includes:

[0020] determining a first average voltage value corresponding to the first power value and a second average voltage value corresponding to the second power value of the heating element;

[0021] The heating operation of the heating element is started or stopped according to the first average voltage value and the second average voltage value.

[0022] Preferably, starting or stopping the heating operation of the heating element according to the first average voltage value and the second average voltage value includes:

[0023] determining a power-on time required for the average voltage value of the heating element to reach the first average voltage value and a power-off time required for the average voltage value of the heating element to reach the second average voltage value;

[0024] The heating operation of the heating element is started or stopped according to the power-on time and the power-off time.

[0025] Preferably, the power-on duration is determined based on a pre-recorded correspondence between the dry-burning duration of the heating element and the power value of the heating element;

[0026] The power-off duration is determined based on a pre-recorded correspondence between the heat release duration of the heating element and the power value of the heating element.

[0027] Preferably, starting or stopping the heating operation of the heating element according to the power-on duration and the power-off duration includes:

[0028] Determine the number of zero crossings in the power-on state according to the power-on duration to obtain a first total number; and determine the number of zero crossings in the power-off state according to the power-off duration to obtain a second total number;

[0029] The heating operation of the heating element is started or stopped using the first total number of times and the second total number of times.

[0030] The present invention further provides a storage medium storing a computer program, wherein the computer program is configured to execute any of the methods described above when running.

[0031] The present invention further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute any one of the methods described above.

[0032] The present invention also provides a household appliance, comprising a device for implementing any of the above-mentioned devices.

[0033] In the technical solution of the present invention, whether the power supply voltage value of the heating element passes through zero is periodically detected, and when it is determined that the power supply voltage value passes through zero, the heating operation of the heating element is started or stopped, so that the current flowing through the relay gradually increases from zero, thereby ensuring that no instantaneous impact current occurs in the relay and extending the service life of the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0035] Figure 1 This is a flow chart of a method for controlling a heating element provided in Example 1 of the present invention;

[0036] Figure 2 A schematic diagram of the voltage and current changes of the alternating current provided by the present invention;

[0037] Figure 3This is a flow chart of a method for controlling a heating element according to a second embodiment of the present invention;

[0038] Figure 4 A schematic diagram of temperature changes caused by the heating operation of the PTC electric heating unit provided in an embodiment of the present application;

[0039] Figure 5 This is a flow chart of a method for controlling a heating element according to a third embodiment of the present invention;

[0040] Figure 6 This is a flow chart of a method for controlling a heating element according to a fourth embodiment of the present invention;

[0041] Figure 7 A diagram showing the relationship between power and time of a PTC electric heating unit provided in an embodiment of the present application;

[0042] Figure 8 A schematic diagram of a PTC electric heating circuit provided by the present invention;

[0043] Figure 9 This is a flow chart of a method for controlling a heating element provided in Example 5 of the present application;

[0044] Figure 10 A schematic structural diagram of the air conditioner provided in an embodiment of the present application.

[0045] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0047] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, the terms "first," "second," and so on, used in this disclosure are 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 referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0049] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0050] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0051] In the process of implementing the solution of the present invention, it was found that the reasons affecting the service life of the relay in the prior art are as follows:

[0052] When the PTC electric heating unit is initially powered on, due to the relatively low resistance of the PTC electric heating unit, there will be an inrush current in the entire circuit. The magnitude of this inrush current is generally 2-2.5 times the current of the circuit under stable operation. This magnitude of inrush current will cause a current shock to the contacts of the PTC electric heating unit's relay, thereby shortening the service life of the relay.

[0053] Based on the above analysis, the present invention provides the following embodiments to solve the above technical problems, including:

[0054] Example 1

[0055] Figure 1 This is a flow chart of a method for controlling a heating element according to a first embodiment of the present invention. Figure 1 As shown, the method includes:

[0056] Step 101: Periodically detect the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage passes through zero;

[0057] In an exemplary embodiment, the heating element may be a PTC electric heating unit or a metal tube;

[0058] In an exemplary embodiment, the heating element may be built into a household appliance with a heating function, which may be an air conditioner with a heating function, or a beauty product that implements functions such as mist heating or steam heating, such as a facial steamer.

[0059] In an exemplary embodiment, the supply voltage is a voltage required for the heating element to operate normally. Taking an air conditioner with a built-in heating element as an example, the supply voltage is 220V AC.

[0060] Step 102: Determine the zero point of the power supply voltage, and control the heating operation of the heating element to start or stop.

[0061] Taking a PTC heating element as an example, controlling whether the PTC heating element is heating is typically done using a relay. Since the voltage phase at the time the relay is switched on and off is unknown, and the PTC heating element is a purely resistive load, the current flowing through the PTC heating element varies at different voltage phases. If the relay is switched on and off at the voltage peak, the inrush current flowing through the PTC heating element is relatively large, causing significant impact on the relay contacts and external interference.

[0062] Figure 2 Schematic diagram of the voltage and current changes of the alternating current provided by the present invention. Figure 2 As shown in the figure, the alternating current has 100 alternating positive and negative polarities per second, that is, 100 zero crossings. When the voltage crosses zero, the current will gradually increase as the voltage starts from zero.

[0063] By adopting the method of the present invention, for a relay that controls whether a heating element starts heating, after the power supply voltage exceeds the current, the relay is controlled to be turned on or off to perform a control operation. At this time, the current flowing through the relay also gradually increases from zero. Therefore, no instantaneous surge current will appear in the relay, thereby extending the service life of the relay.

[0064] The method provided in the first embodiment of the present invention periodically detects the magnitude of the power supply voltage of the heating element, determines whether the magnitude of the power supply voltage crosses the zero point, determines when the magnitude of the power supply voltage crosses the zero point, controls the start or stop of the heating operation of the heating element, and makes the current flowing through the relay gradually increase from zero, thereby ensuring that no instantaneous surge current occurs in the relay and extending the service life of the relay.

[0065] Example 2

[0066] Figure 3 This is a flow chart of a method for controlling a heating element according to the second embodiment of the present invention. Figure 3 As shown, the method includes:

[0067] After receiving an instruction for controlling the heating element to start heating and before receiving an instruction for controlling the heating element to stop heating, steps 201 to 208 are executed in a loop until an instruction for controlling the heating element to stop heating is received, and the process ends.

[0068] Taking the application of the heating element in the air conditioner as an example, if a heating start instruction is received, it is confirmed that an instruction for controlling the heating element to start heating is received; if a heating stop instruction is received, it is confirmed that an instruction for controlling the heating element to stop heating is received.

[0069] Steps 201 to 208 are described below:

[0070] Step 201: Periodically detect the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage passes through zero;

[0071] In an exemplary embodiment, the heating element may be a PTC electric heating unit or a metal tube;

[0072] In an exemplary embodiment, the heating element may be built into a household appliance with a heating function, which may be an air conditioner with a heating function, or a beauty product that implements functions such as mist heating or steam heating, such as a facial steamer.

[0073] In an exemplary embodiment, the supply voltage is a voltage required for the heating element to operate normally. Taking an air conditioner with a built-in heating element as an example, the supply voltage is 220V AC.

[0074] If it is detected that the power supply voltage crosses the zero point, step 202 is executed; otherwise, step 201 is continued;

[0075] Step 202: Control the heating operation of the heating element to be in an activated state;

[0076] The relay connected to the heating element can be controlled to be in an on state to start the heating operation.

[0077] Step 203: Detect the power value of the heating element after heating;

[0078] Step 204: determine whether the power value after heating reaches a preset first power value;

[0079] The first power value is determined according to an externally set target temperature; when the power value of the heating element after heating reaches the first power value, the generated temperature can at least reach the target temperature.

[0080] Take the air conditioner as an example. Figure 4This is a schematic diagram of the temperature change caused by the heating operation of the PTC electric heating unit provided in the embodiment of the present application. Figure 4 As shown, the return air temperature detection probe can be used to detect the return air temperature, and the outlet air temperature detection probe can be used to detect the outlet air temperature. The heating purpose of the PTC electric heating unit is to make the outlet air temperature at least equal to the externally set target temperature. For example, if the target temperature is 28°C, the first power value can be set to achieve an outlet air temperature of 30°C.

[0081] In the existing technology, when the PTC electric heating unit is turned on and off, the air outlet temperature of the air conditioner is greatly affected, and the air outlet temperature is unstable, sometimes hot and sometimes cold. 3 / h, the power of the PTC electric heating unit is 900W. After turning on the PTC electric heating unit, the outlet air temperature rises by about 5°C. Since the outlet air temperature rises too quickly, the heating effect is less comfortable.

[0082] By detecting the power value of the PTC electric heating unit during the heating process based on the preset first power value in the embodiment of the present invention, the variation amplitude of the power value can be effectively controlled, thereby effectively controlling the outlet air temperature, ensuring that the rising speed of the outlet air temperature is consistent with the human body's physical sensation habits, and improving the heating comfort.

[0083] The advantages are illustrated here using air conditioners as an example. The same applies to other electrical appliances that require heating, so I will not go into details here.

[0084] If the power value after heating reaches the first power value, execute step 205; otherwise, continue to execute step 204;

[0085] Step 205: Periodically detect the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage passes through zero;

[0086] If it is detected that the power supply voltage crosses zero, step 206 is executed; otherwise, step 205 is continued;

[0087] Step 206: Control the heating operation of the heating element to be in a stopped state;

[0088] Step 207: Detect the power value of the heating element after heat release;

[0089] Step 208: Determine whether the power value after heat release reaches a preset second power value;

[0090] The second power value is determined according to an externally set target temperature, and when the power value of the heating element after heat dissipation reaches the second power value, the generated temperature is not excessively lower than the target temperature.

[0091] Taking an air conditioner as an example, if the target temperature is 28°C, the second power value can be set to enable the air outlet temperature to reach 26°C.

[0092] By detecting the power value after heat release, it can be ensured that the power value of the heating component after heat dissipation is not too low, so that the perceived temperature feels too cold, which is in line with human body perception habits.

[0093] If the power value after heat release reaches the second power value, step 201 is executed; otherwise, step 208 is continued.

[0094] The method provided in the second embodiment of the present invention periodically detects the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage crosses zero. When the magnitude of the power supply voltage crosses zero, the heating operation of the heating element is started or stopped, so that the current flowing through the relay gradually increases from zero, thereby ensuring that no instantaneous surge current occurs in the relay and extending the service life of the relay. By adjusting the power of the PTC electric heating unit to an appropriate magnitude after heating and after heat dissipation, the problem of air temperature fluctuation caused by the PTC electric heating unit being too high when it is turned on and off is overcome, thereby improving the heating comfort.

[0095] Example 3

[0096] Figure 5 This is a flow chart of a method for controlling a heating element according to the third embodiment of the present invention. Figure 5 As shown, the method includes:

[0097] After receiving an instruction for controlling the heating element to start heating and before receiving an instruction for controlling the heating element to stop heating, steps 301 to 312 are executed in a loop until an instruction for controlling the heating element to stop heating is received, and the process ends.

[0098] Taking the application of the heating element in the air conditioner as an example, if a heating start instruction is received, it is confirmed that an instruction for controlling the heating element to start heating is received; if a heating stop instruction is received, it is confirmed that an instruction for controlling the heating element to stop heating is received.

[0099] Steps 301 to 312 are described below:

[0100] Step 301: Periodically detect the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage passes through zero;

[0101] In an exemplary embodiment, the heating element may be a PTC electric heating unit or a metal tube;

[0102] In an exemplary embodiment, the heating element may be built into a household appliance with a heating function, which may be an air conditioner with a heating function, or a beauty product that implements functions such as mist heating or steam heating, such as a facial steamer.

[0103] In an exemplary embodiment, the supply voltage is a voltage required for the heating element to operate normally. Taking an air conditioner with a built-in heating element as an example, the supply voltage is 230V AC.

[0104] If it is detected that the power supply voltage crosses zero, step 302 is executed; otherwise, step 301 is continued;

[0105] Step 302: Control the heating operation of the heating element to be in the starting state;

[0106] The relay connected to the heating element can be controlled to be in an on state to start the heating operation.

[0107] Step 303: Detect the power value of the heating element after heating;

[0108] Step 304: determine whether the power value after heating reaches a preset first power value;

[0109] The first power value is determined according to an externally set target temperature; when the power value of the heating element after heating reaches the first power value, the generated temperature can at least reach the target temperature.

[0110] Take the air conditioner as an example. Figure 4 This is a schematic diagram of the temperature change caused by the heating operation of the PTC electric heating unit provided in the embodiment of the present application. Figure 4 As shown, the return air temperature can be detected by the return air temperature detection probe, and the outlet air temperature can be detected by the outlet air temperature detection probe. The heating purpose of the PTC electric heating unit is to make the outlet air temperature at least equal to the target temperature set externally.

[0111] In the existing technology, when the PTC electric heating unit is turned on and off, the air outlet temperature of the air conditioner is greatly affected, and the air outlet temperature is unstable, sometimes hot and sometimes cold. 3 / h, the power of the PTC electric heating unit is 900W. After turning on the PTC electric heating unit, the air outlet temperature rises by about 5°C. Since the air outlet temperature rises too quickly, the heating effect is less comfortable. For example, if the target temperature is 28°C, the first power value can be set to achieve an air outlet temperature of 30°C.

[0112] By detecting the power value of the PTC electric heating unit during the heating process based on the preset first power value in the embodiment of the present invention, the variation amplitude of the power value can be effectively controlled, thereby effectively controlling the outlet air temperature, ensuring that the rising speed of the outlet air temperature is consistent with the human body's physical sensation habits, and improving the heating comfort.

[0113] The advantages are illustrated here using air conditioners as an example. The same applies to other electrical appliances that require heating, so I will not go into details here.

[0114] If the power value after heating reaches the first power value, the following steps may be performed:

[0115] Step 300: Determine the actual temperature of the environment to be measured;

[0116] Taking the air conditioner as an example, the actual temperature of the current air outlet can be detected;

[0117] Step 310: Adjust the first power value according to the actual temperature and the preset target temperature.

[0118] If the actual temperature is smaller than the target temperature, it means that the temperature generated by the current power value is too low, and the power value of the heating element needs to be further increased. Therefore, the first power value needs to be increased; conversely, if the actual temperature is larger than the target temperature, it means that the temperature generated by the current power value is too high, and the power value of the heating element needs to be appropriately reduced. Therefore, the first power value needs to be reduced.

[0119] Taking the air conditioner as an example, the outlet temperature is used as the actual temperature of the environment to be measured. If the target temperature set for the heating request is 30°C and the outlet temperature is 28°C, it means that the current power value of the heating element is too low, and the first power value needs to be increased to increase the outlet temperature.

[0120] By adjusting the first power value, it can be ensured that the temperature generated by the power value of the heating element can match the target temperature value to meet the heating demand.

[0121] If the power value after heating reaches the first power value, execute step 305; otherwise, continue to execute step 306;

[0122] Step 305: Periodically detect the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage crosses zero;

[0123] If it is detected that the power supply voltage crosses zero, step 306 is executed; otherwise, step 305 is continued;

[0124] Step 306: Control the heating operation of the heating element to be in a stopped state;

[0125] Step 307: Detect the power value of the heating element after heat release;

[0126] Step 308: Determine whether the power value after heat release reaches a preset second power value;

[0127] The second power value is determined according to an externally set target temperature, and when the power value of the heating element after heat dissipation reaches the second power value, the generated temperature is not excessively lower than the target temperature.

[0128] Taking an air conditioner as an example, if the target temperature is 28°C, the second power value can be set to enable the air outlet temperature to reach 26°C.

[0129] By detecting the power value after heat release, it can be ensured that the power value of the heating component after heat dissipation is not too low, so that the perceived temperature feels too cold, which is in line with human body perception habits.

[0130] If the power value after heat release reaches the second power value, the following steps may be performed:

[0131] Step 311: Determine the actual temperature of the environment to be measured;

[0132] Taking the air conditioner as an example, the actual temperature of the current air outlet can be detected;

[0133] Step 312: Adjust the second power value according to the actual temperature and the preset target temperature.

[0134] If the actual temperature is smaller than the target temperature, it means that the temperature generated by the current power value is too low, and the power value of the heating element needs to be further increased. Therefore, the second power value needs to be increased; conversely, if the actual temperature is larger than the target temperature, it means that the temperature generated by the current power value is too high, and the power value of the heating element needs to be appropriately reduced. Therefore, the second power value needs to be reduced.

[0135] By adjusting the second power value, it can be ensured that the temperature generated by the power value of the heating element can match the target temperature value to meet the heating demand.

[0136] If the power value after heat release reaches the second power value, step 301 is executed; otherwise, step 308 is continued.

[0137] The method provided in the third embodiment of the present invention periodically detects the magnitude of the power supply voltage of the heating element, determines whether the magnitude of the power supply voltage passes through zero, determines that the magnitude of the power supply voltage passes through zero, and controls the start or stop of the heating operation of the heating element, so that the current flowing through the relay gradually increases from zero, thereby ensuring that there will be no instantaneous surge current in the relay and extending the service life of the relay. By adjusting the power of the PTC electric heating unit to an appropriate magnitude after heating and after heat dissipation, the problem of the PTC electric heating unit causing the air temperature to fluctuate when it is turned on and off due to the excessive power of the PTC electric heating unit is overcome, thereby improving the heating comfort. By comparing the actual temperature of the environment to be tested with the target temperature, and adjusting the first power value and the second power value, it can be ensured that the temperature generated by the heating element meets the heating requirements and improves the accuracy of temperature control.

[0138] Example 4

[0139] Figure 6 This is a flow chart of a method for controlling a heating element according to a fourth embodiment of the present invention. Figure 6 As shown, the method includes:

[0140] After receiving an instruction for controlling the heating element to start heating and before receiving an instruction for controlling the heating element to stop heating, steps 401 to 408 are executed in a loop until an instruction for controlling the heating element to stop heating is received, and the process ends.

[0141] Taking the application of the heating element in the air conditioner as an example, if a heating start instruction is received, it is confirmed that an instruction for controlling the heating element to start heating is received; if a heating stop instruction is received, it is confirmed that an instruction for controlling the heating element to stop heating is received.

[0142] Before executing the above steps, the first average voltage magnitude corresponding to the first power value reached by the heating element after heating and the second average voltage magnitude corresponding to the second power value reached after heat dissipation are determined. By adjusting the detection of the average voltage values ​​of the PTC electric heating unit after heating and heat dissipation, the power of the PTC electric heating unit is controlled to ensure the power variation range of the PTC electric heating unit, and the implementation method is simple.

[0143] Steps 401 to 408 are described below:

[0144] Step 401: Periodically detect the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage passes through zero;

[0145] In an exemplary embodiment, the heating element may be a PTC electric heating unit or a metal tube;

[0146] In an exemplary embodiment, the heating element may be built into a household appliance with a heating function, which may be an air conditioner with a heating function, or a beauty product that implements functions such as mist heating or steam heating, such as a facial steamer.

[0147] In an exemplary embodiment, the supply voltage is a voltage required for the heating element to operate normally. Taking an air conditioner with a built-in heating element as an example, the supply voltage is 220V AC.

[0148] If it is detected that the power supply voltage crosses zero, step 403 is executed; otherwise, step 402 is continued;

[0149] Step 402: Control the heating operation of the heating element to be in an activated state;

[0150] The relay connected to the heating element can be controlled to be in an on state to start the heating operation.

[0151] Step 403: detecting the average voltage of the power supply voltage of the heating element;

[0152] The average voltage value during the heating process is equal to the ratio of the sum of the voltage values ​​in the power-on state to the power-on time.

[0153] Step 404: determine whether the average voltage reaches a first average voltage;

[0154] If the voltage average value reaches the first average voltage value, then execute step 405; otherwise, continue to execute step 404;

[0155] Step 405: Periodically detect the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage passes through zero;

[0156] If it is detected that the power supply voltage crosses the zero point, step 406 is executed; otherwise, step 405 is continued;

[0157] Step 407: Control the heating operation of the heating element to be in a stopped state;

[0158] Step 408: Detect the average voltage of the power supply voltage of the heating element;

[0159] The average voltage value during the heat release process is equal to the ratio of the sum of the voltage values ​​in the power-on state to the sum of the power-on time and the power-off time.

[0160] Step 409: Determine whether the power value after heat release reaches the second voltage average value;

[0161] If the voltage average value reaches the first average voltage value, step 402 is executed; otherwise, step 409 is executed.

[0162] Before receiving the instruction to stop heating, steps 402 to 409 are executed in a loop; after receiving the instruction to stop heating, the process ends.

[0163] In the above process, the average voltage of the heating element can be controlled by the power-on time and power-off time of the heating element, thereby achieving accurate control of the average voltage.

[0164] The power-on duration is the time required for the average voltage of the heating element to reach the first average voltage;

[0165] The power-off duration is the duration required for the average voltage level of the heating element to reach the second average voltage level.

[0166] When the air conditioner has a PTC electric heating unit, first detect whether the power supply voltage of the PTC electric heating unit passes through zero, and then energize or de-energize the relay and electronic switch that control the power supply of the PTC electric heating unit when the voltage passes through zero according to the actual power requirement of the PTC electric heating unit, so as to achieve the purpose of controlling the heating power of the PTC electric heating unit by adjusting the average voltage.

[0167] Figure 7 This is a diagram showing the relationship between the power and time of the PTC electric heating unit provided in the embodiment of the present application. Figure 7 As shown, according to Figure 7 The curves shown can respectively establish the corresponding relationship between the dry burning time of the heating element and the power of the heating element, and the corresponding relationship between the heat release time of the heating element and the power of the heating element. According to the established corresponding relationships, the power-on time and the power-off time are determined.

[0168] The method provided in the fourth embodiment of the present invention periodically detects the magnitude of the power supply voltage of the heating element to determine whether the magnitude of the power supply voltage passes through zero, and controls the start or stop of the heating operation of the heating element when the magnitude of the power supply voltage passes through zero, so that the current flowing through the relay gradually increases from zero, thereby ensuring that there is no instantaneous surge current in the relay and extending the service life of the relay. By adjusting the detection of the average voltage value of the PTC electric heating unit after heating and after heat dissipation, the power of the PTC electric heating unit is controlled to ensure the power variation amplitude of the PTC electric heating unit, and the implementation method is simple; in addition, by controlling the power value of the PTC electric heating unit to an appropriate size, the problem of the air temperature fluctuation caused by the PTC electric heating unit being too large when the PTC electric heating unit is turned on and off is overcome, thereby improving the heating comfort.

[0169] Example 5

[0170] This embodiment uses a PTC electric heating unit as the heating element and is applied to an air conditioner as an example. In this embodiment, based on the duration of each occurrence of the zero-crossing signal, a first total number K1 of occurrences of the zero-crossing signal corresponding to the power-on duration and a second total number K2 of occurrences of the zero-crossing signal corresponding to the power-off duration are determined, and the first total number K1 and the second total number K2 are used to start or stop the heating operation of the heating element.

[0171] Compared with the prior art that uses a timer to calculate the duration, the calculation of the duration is completed with the help of a zero-crossing signal detection mechanism, which saves the design cost of the hardware structure and is simple and convenient to implement.

[0172] Figure 8 The circuit diagram of the PTC electric heating unit provided by the present invention is shown in FIG. Figure 8 As shown, in the circuit, the PTC electric heating unit is connected between the live wire and the neutral wire, and the conduction of the PTC electric heating unit is controlled by a relay, and a zero-crossing detection circuit is used to detect whether the power supply voltage of the PTC electric heating unit passes through zero.

[0173] exist Figure 8 In the circuit shown, the relay will produce contact jitter when it is turned on and off, which is detrimental to the life of the relay's own contacts and also generates electromagnetic interference to the outside world. The present invention avoids the occurrence of the above situation to the greatest extent by controlling the relay to be connected or disconnected without load.

[0174] Furthermore, the current limiting switches S1 and S2 used with the PTC heating unit are electronic switches. If these electronic switches fail, the PTC heating unit may not be able to shut down. In the above circuit, using a bidirectional thyristor T2 as the electronic switch and connecting it in series via a relay greatly reduces the risk of the PTC heating unit not being able to shut down.

[0175] See also Figure 7 As can be seen from the content, when a PTC electric heating unit is first powered on, the voltage fluctuation is very small, and the current in the circuit is an inrush current. The inrush power takes about 5-15 seconds to reach its peak. To control the power of the PTC electric heating unit and minimize temperature fluctuations, the present invention uses an electronic switch. The electronic switch can be turned on and off quickly and has no contact jitter to achieve power regulation of the PTC electric heating unit.

[0176] The power regulation of PTC electric heating units is a method of controlling the power by turning several PTC electric heating units on and off separately. The adjustable power range is very limited. In addition, as the number of PTC electric heating units increases, the cost in the production, manufacturing, and assembly processes increases. In addition, some safety certifications also require that each group of independently powered PTC electric heating units must have an independent hardware temperature limiter, which further increases the cost. This method solves the above problems with a small number of electronic components and software, and has a larger power adjustment range.

[0177] Figure 9 This is a flow chart of the control method of the heating element provided in Example 5 of the present application. Figure 9 As shown, the method includes:

[0178] Step 501: Turn on the air conditioner.

[0179] Step 502: determine whether the PTC electric heating unit needs to be turned on;

[0180] If the PTC electric heating unit does not need to be turned on, return to step 502 to continue querying;

[0181] If the PTC electric heating unit needs to be turned on, go to step 503;

[0182] Step 503: Perform initial configuration of parameters and detect the return air temperature T1 and power supply voltage U1 of the PTC electric heating unit;

[0183] The initial configuration includes: the PTC electric heating unit power-on status flag position 1 (PTC electric heating unit = 1), the power-on zero-crossing counter K1 is cleared (K1 = 0), and the power-off zero-crossing counter K2 is cleared (K2 = 0);

[0184] Step 504: Determine the number of zero-crossing points N1 and the number of zero-crossing points N2 of the PTC electric heating unit when it is powered on, based on the wind temperature value T1, the power supply voltage U1, and the required air outlet temperature of the entire device, where N1 and N2 are both integers greater than or equal to 0.

[0185] Step 505: Detect the power supply voltage of the PTC electric heating unit using a zero-crossing detection circuit;

[0186] Step 506: Determine whether the power supply voltage passes through zero;

[0187] If the power supply voltage is detected to be zero-crossing, step 507 is executed; otherwise, step 506 is executed;

[0188] Step 507: Control the relay of the PTC electric heating unit to be energized, the electronic switch to be turned on, and the zero-crossing counter to be energized + 1 (K1=K1+1), and continue to detect whether the power supply voltage crosses zero;

[0189] Step 508: Determine whether the value K1 of the power-on zero-crossing counter is greater than or equal to the power-on zero-crossing number N1;

[0190] If the value K1 is greater than or equal to N1, execute step 509; otherwise, execute step 505;

[0191] Step 509: Control the PTC electric heating unit relay to be powered off, the electronic switch to be turned off, the power-on zero-crossing counter K1 to be cleared (K1=0), and the power-off zero-crossing counter K2 to be set to 1 (K2=1).

[0192] Step 510: Detect whether the power supply voltage of the PTC electric heating unit crosses zero using a zero-crossing detection circuit;

[0193] Step 511: determine whether the power supply voltage passes through zero;

[0194] If the zero crossing point of the power supply voltage is detected, step 512 is executed; otherwise, step 511 is executed;

[0195] Step 512: Update the value of the power-off zero-crossing counter K2 and add 1 (K2=K2+1);

[0196] Step 513: Determine whether the value of the power-off zero-crossing counter K2 is greater than or equal to the power-off zero-crossing number N2;

[0197] If the value K2 is greater than or equal to N2, then execute step 514; otherwise, execute step 510;

[0198] Step 514: determine whether it is necessary to turn on the PTC electric heating unit to perform a heating operation;

[0199] If the PTC electric heating unit needs to be turned on to perform the heating operation, step 503 is executed; otherwise, step 515 is executed.

[0200] Step 515 , update the PTC electric heating unit power-on status flag position to 0 (PTC electric heating unit=0), and jump to step 502 .

[0201] In the above process, the value of at least one of the number of power-on zero-crossing points N1 and the number of power-off zero-crossing points N2 may be dynamically adjusted to make the air outlet temperature more closely match the set target temperature.

[0202] You can set the upper and lower limits of temperature control according to the target temperature. For example, if the target temperature is 28°C, the upper limit can be set to 30°C and the lower limit can be set to 26°C.

[0203] If it is detected that the temperature generated during the heating process is lower than the upper limit of the target temperature, the value of the number of power-on zero-crossing points N1 can be increased; if it is detected that the temperature generated during the heating process is higher than the upper limit of the target temperature, the value of the number of power-on zero-crossing points N1 can be reduced.

[0204] If it is detected that the temperature generated during the heat release process is lower than the lower limit of the target temperature, the value of the number of power-on zero crossings N1 can be increased; if it is detected that the temperature generated during the heat release process is higher than the lower limit of the target temperature, the value of the number of power-off zero crossings N2 can be reduced.

[0205] The method provided in the fifth embodiment of the present invention periodically detects the magnitude of the power supply voltage of the heating element, determines whether the magnitude of the power supply voltage crosses zero, determines that the magnitude of the power supply voltage crosses zero, controls the heating operation of the heating element to start or stop, and makes the current flowing through the relay gradually increase from zero, thereby ensuring that there is no instantaneous surge current in the relay and extending the service life of the relay. By adjusting the detection of the average value of the voltage of the PTC electric heating unit after heating and after heat dissipation, the power of the PTC electric heating unit is controlled, and the variation amplitude of the power of the PTC electric heating unit is guaranteed. The implementation method is simple. In addition, by controlling the power value of the PTC electric heating unit to an appropriate size, the problem of the air temperature fluctuation caused by the PTC electric heating unit being too large when the PTC electric heating unit is turned on and off is overcome, thereby improving the heating comfort. By counting the number of zero-crossing occurrences, the power-on time and power-off time of the PTC electric heating unit are controlled, which is simple and convenient, saving the design cost of the hardware structure.

[0206] An embodiment of the present invention provides a storage medium storing a computer program, wherein the computer program is configured to execute any of the methods described above when running.

[0207] An embodiment of the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to perform any of the methods described above.

[0208] An embodiment of the present invention provides a household appliance, comprising an apparatus for implementing any of the above methods.

[0209] When the household appliance is an air conditioner, the device for realizing the control function of heating by the PTC electric heating unit can be embedded into the controller of the household appliance as a software module.

[0210] Figure 10 This is a schematic diagram of the structure of the air conditioner provided in the embodiment of the present application. Figure 10As shown, the control system of the PTC electric heating unit in the air conditioner includes a CPU, a storage unit, a power supply unit, a display unit, a detection / control unit and a PTC electric heating unit; wherein:

[0211] CPU, used to control the operation of the entire air conditioning system, including the control of the PTC electric heating unit;

[0212] a storage unit for storing information;

[0213] A display unit, used to display air-conditioning operation information and fault information, wherein the fault information includes electric heating fault information;

[0214] Detection / control unit, used to control the operation of components in the air conditioner including the PTC electric heating unit, and detect the voltage zero crossing point of the PTC electric heating unit, the return air temperature value and the outlet air temperature value of the PTC electric heating unit;

[0215] The PTC electric heating unit is used to heat the air to a predetermined temperature.

[0216] Power supply unit, used to supply power to functional modules such as CPU, storage unit, display unit, detection / control unit, PTC electric heating unit, etc.

[0217] The CPU exchanges information with the storage unit and controls the display of the display unit; it also exchanges information with the control unit, issues control instructions to the control unit, and collects control information, component operation status and other information fed back by the control unit;

[0218] The control unit controls the operation of the air conditioner components including the PTC electric heating unit, and detects the voltage zero crossing point of the PTC electric heating unit, the return air temperature value, and the outlet air temperature value of the PTC electric heating unit;

[0219] When the air conditioner is equipped with a PTC electric heating unit, the zero crossing point of the power supply voltage of the PTC electric heating unit is first detected, and the relay and electronic switch that control the power supply of the PTC electric heating unit are energized or de-energized when the voltage crosses the zero point according to the actual power requirement of the PTC electric heating unit, so as to achieve the purpose of controlling the heating power of the PTC electric heating unit by adjusting the average voltage.

[0220] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for controlling a heating element, characterized in that: Applied to an air conditioner, the method comprises: Periodically check whether the power supply voltage value of the heating element passes through zero; determining that a supply voltage value crosses a zero point, and starting or stopping a heating operation of the heating element; After starting the heating operation of the heating element, detecting the power value of the heating element after heating; If the power value after heating is less than a preset first power value, the heating operation of the heating element is not allowed to be stopped, wherein the first power value is used to control the air outlet temperature of the air conditioner after the heating operation of the heating element to be greater than an externally set target temperature value; After stopping the heating operation of the heating element, detecting the power value of the heating element after heat release; If the power value after heat release is less than a preset second power value, the heating operation of the heating element is not allowed to be started, wherein the second power value is used to control the air outlet temperature of the air conditioner after the heat release operation of the heating element to be less than the target temperature value set externally.

2. The method according to claim 1, wherein The method further comprises: Periodically obtain the actual temperature value of the environment to be measured; At least one of the first power value and the second power value is adjusted according to the actual temperature value and the target temperature value.

3. The method according to claim 1, wherein The starting or stopping of the heating operation of the heating element comprises: determining a first average voltage value corresponding to the first power value and a second average voltage value corresponding to the second power value of the heating element; The heating operation of the heating element is started or stopped according to the first average voltage value and the second average voltage value.

4. The method according to claim 3, wherein The starting or stopping the heating operation of the heating element according to the first average voltage value and the second average voltage value includes: determining a power-on time required for the average voltage value of the heating element to reach the first average voltage value and a power-off time required for the average voltage value of the heating element to reach the second average voltage value; The heating operation of the heating element is started or stopped according to the power-on time and the power-off time.

5. The method according to claim 4, wherein: The power-on duration is determined based on a pre-recorded correspondence between the dry-burning duration of the heating element and the power value of the heating element; The power-off duration is determined based on a pre-recorded correspondence between the heat release duration of the heating element and the power value of the heating element.

6. The method according to claim 4, wherein The starting or stopping of the heating operation of the heating element according to the power-on duration and the power-off duration includes: Determine the number of zero crossings in the power-on state according to the power-on duration to obtain a first total number; and determine the number of zero crossings in the power-off state according to the power-off duration to obtain a second total number; The heating operation of the heating element is started or stopped using the first total number of times and the second total number of times.

7. A storage medium, characterized in that: The storage medium stores a computer program, wherein the computer program is configured to execute the method according to any one of claims 1 to 6 when executed.

8. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to run the computer program to perform the method according to any one of claims 1 to 6.

9. A household appliance, characterized in that: The method comprises an apparatus for implementing the method according to any one of claims 1 to 6.

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