Electric heating equipment control method, device, system and electric heating equipment

Abstract

The present application relates to a control method, device, system and electric heating equipment for electric heating equipment. When the electric heating equipment is operating at a heating power less than a preset power threshold, that is, when it is in a low-power operating state, it is possible to perform real-time voltage sampling during the operation of the electric heating equipment to obtain voltage sampling parameters. Afterwards, a zero-crossing trend analysis is performed on the voltage sampling parameters to determine whether the electric heating equipment is in a zero-crossing state, and when the electric heating equipment is in a zero-crossing state, the electric heating equipment is controlled to maintain a stable slow-heating state. In the above scheme, the zero-crossing detection of the electric heating equipment is directly achieved through the analysis of the voltage sampling parameters, without the need to set up an additional hardware circuit for zero-crossing detection, thereby effectively alleviating the problem of high cost of the slow-heating circuit.

Description

Technical Field

[0001] The present application relates to the field of heating technology, and in particular to a control method, device, system and electric heating equipment for electric heating equipment. Background Art

[0002] Electric heating devices include IH (induction heating) rice cookers, induction cookers, and induction heaters. Their principle is to pass high-frequency alternating current through a coil, generating a high-frequency alternating magnetic field near the coil. This field induces eddy currents in the metal cookware, which in turn generates Joule heat, heating the cookware and thus the food. IH heating devices are popular due to their advantages, including the absence of open flames, high power consumption, and excellent heat transfer efficiency.

[0003] To meet user needs, electric heating equipment often features a low-power, slow-heating mode. During operation, a zero-crossing detection circuit detects the zero-crossing point, controlling the thyristor (SCR) to chop the current, enabling stable operation and slow-heating at low power. However, this slow-heating mode requires numerous peripheral components, significantly increasing the cost of the circuit. Summary of the Invention

[0004] Based on this, it is necessary to provide an electric heating equipment control method, device, system and electric heating equipment to address the problem of high cost of slow-fire heating circuits. The electric heating equipment control method, device, system and electric heating equipment provided in this application do not require additional zero-crossing detection hardware circuits when performing slow-fire heating control, thereby effectively alleviating the problem of high cost of slow-fire heating circuits.

[0005] A method for controlling an electric heating device comprises: if the heating power of the electric heating device is less than a preset power threshold, obtaining a voltage sampling parameter of the electric heating device; performing a zero-crossing trend analysis based on the voltage sampling parameter to obtain a zero-crossing detection result of the electric heating device; and if the zero-crossing detection result indicates the occurrence of a zero-crossing event, maintaining a slow-heat heating state.

[0006] The above-described electric heating device control method can perform real-time voltage sampling during the operation of the electric heating device to obtain voltage sampling parameters when the electric heating device is operating at a heating power less than a preset power threshold, that is, when it is in a low-power operating state. Zero-crossing trend analysis of the voltage sampling parameters is then performed to determine whether the electric heating device is in a zero-crossing state. If the electric heating device is in a zero-crossing state, the electric heating device is controlled to maintain a stable slow-heating state. In the above scheme, zero-crossing detection of the electric heating device is directly achieved through analysis of the voltage sampling parameters, eliminating the need for additional hardware circuitry for zero-crossing detection, thereby effectively alleviating the high cost of slow-heating circuits.

[0007] In one embodiment, the zero-crossing trend analysis is performed based on the voltage sampling parameters to obtain the zero-crossing detection result of the electric heating equipment, including: performing trend analysis based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment to obtain trend parameters; performing zero-crossing analysis based on the current trend parameters and the trend parameters obtained from the previous round of trend analysis to obtain the zero-crossing detection result of the electric heating equipment.

[0008] In one embodiment, the trend analysis is performed based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment to obtain the trend parameters, including: calculating the initial trend parameters based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment; and performing filtering analysis on the initial trend parameters to obtain the trend parameters.

[0009] In one embodiment, the initial trend parameter includes an initial slope parameter; the initial trend parameter is calculated based on the voltage sampling parameter at the current sampling moment and the voltage sampling parameter at the previous sampling moment, including: obtaining a preset voltage coordinate system, where the voltage coordinate system is constructed by historical voltage sampling parameters; extracting the coordinates of the voltage sampling parameter at the current sampling moment in the voltage coordinate system and the coordinates of the voltage sampling parameter at the previous sampling moment in the voltage coordinate system; and performing slope calculation based on the extracted coordinates to obtain the initial slope parameter.

[0010] In one embodiment, performing filtering analysis on the initial trend parameter to obtain the trend parameter includes: combining the trend parameter obtained by the previous round of trend analysis with the initial trend parameter to perform a filtering pass to obtain the trend parameter.

[0011] In one embodiment, the trend parameter includes a slope parameter; the zero-crossing analysis is performed based on the current trend parameter and the trend parameter obtained in the previous round of trend analysis to obtain the zero-crossing detection result of the electric heating device, including: if the current slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative, it is determined that a zero-crossing event has occurred in the electric heating device.

[0012] In one embodiment, if the current slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative, it is determined that a zero-crossing event has occurred in the electric heating device, including: obtaining a time identifier; calculating the time interval between the current time identifier and the previous time identifier; if the time interval is within a preset time threshold range, it is determined that a zero-crossing event has occurred in the electric heating device; the time identifier is the time corresponding to when the slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative.

[0013] In one embodiment, if the heating power of the electric heating device is less than a preset power threshold, before obtaining the voltage sampling parameters of the electric heating device, it also includes: if the electric heating device enters a continuous heating operation state, obtaining the heating power of the electric heating device and comparing and analyzing it with the preset power threshold.

[0014] In one embodiment, if the electric heating device enters a continuous heating operation state, the heating power of the electric heating device is obtained, and before being compared and analyzed with a preset power threshold, it also includes: when the electric heating device starts to run, the electric heating device is powered on and self-tested; if the power-on self-test is successful, it is detected whether the heating object of the electric heating device is in the heating area; if the heating object is in the heating area, the electric heating device is controlled to enter a continuous heating operation state.

[0015] A control device for an electric heating device comprises: a parameter acquisition module for acquiring a voltage sampling parameter of the electric heating device if the heating power of the electric heating device is less than a preset power threshold; a zero-crossing detection module for performing a zero-crossing trend analysis based on the voltage sampling parameter to obtain a zero-crossing detection result of the electric heating device; and a slow-heat control module for maintaining a slow-heat heating state if the zero-crossing detection result indicates the occurrence of a zero-crossing event.

[0016] A control system for electric heating equipment includes a filter circuit, a controller and a drive control circuit. The filter circuit is connected to the controller, and the controller is connected to the drive control circuit. The filter circuit filters the working voltage of the electric heating equipment and transmits it to the controller. The controller outputs an enable signal to the drive control circuit based on the filtered working voltage and adopts the electric heating equipment control method as described above to adjust the operating state of the drive control circuit and maintain a slow heating state.

[0017] An electric heating device comprises the above-mentioned electric heating device control system.

[0018] In one embodiment, the electric heating device is an electromagnetic heating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 This is a flow chart of a method for controlling an electric heating device in one embodiment of the present application;

[0021] Figure 2 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0022] Figure 3 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0023] Figure 4 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0024] Figure 5 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0025] Figure 6 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0026] Figure 7 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0027] Figure 8 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0028] Figure 9 This is a flow chart of a method for controlling an electric heating device in another embodiment of the present application;

[0029] Figure 10 This is a schematic diagram of a slow-heat heating process of an electric heating device in one embodiment of the present application;

[0030] Figure 11 This is a schematic diagram of the zero-crossing detection process in one embodiment of the present application;

[0031] Figure 12 This is a structural diagram of an electric heating equipment control device in one embodiment of the present application;

[0032] Figure 13 This is a structural diagram of an electric heating equipment control device in another embodiment of the present application;

[0033] Figure 14 This is a structural diagram of an electric heating equipment control device in another embodiment of the present application;

[0034] Figure 15 This is a structural diagram of an electric heating device control system in one embodiment of the present application;

[0035] Description of reference numerals: 152 - filter circuit, 154 - controller, 156 - drive control circuit. DETAILED DESCRIPTION

[0036] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0037] See also Figure 1 , a method for controlling an electric heating device, comprising steps 102 , 104 and 106 .

[0038] Step 102: If the heating power of the electric heating device is less than a preset power threshold, a voltage sampling parameter of the electric heating device is obtained.

[0039] Specifically, the electric heating device control method provided in this application is applied to electric heating devices, wherein the electric heating device refers to a device that converts input electrical energy into thermal energy to achieve a heating operation, including but not limited to a resistance heating device and an electromagnetic heating (electromagnetic induction heating) device. Therefore, the electric heating device provided in this application can be an electric water heater, an electromagnetic cooker, an induction heating furnace, a resistance heating rice cooker, or an IH rice cooker, etc., without specific limitation.

[0040] The electric heating device includes a heating device, a drive control circuit that controls the operation of the heating device, a heating object for holding the required heating items (such as pots, etc.), a filter circuit required for voltage sampling, and a controller. The electric heating device control method is specifically implemented in the controller. The slow-heating state is a state of heating at a relatively low power. If the electric heating device is to enter the low-power slow-heating operation state, it is not only necessary to control the heating power of the electric heating device to be less than a preset low-power threshold (that is, to be in a low-power operation state), but also to control the on-off of the power switch tube in the drive control circuit through the zero-crossing detection result, so as to make the electric heating device run stably at low power by chopping half the wave at low power, thereby maintaining the slow-heating state. Therefore, in the low-power slow-heating operation state, how to realize zero-crossing detection is particularly important.

[0041] The preset power threshold is not unique; any value indicating that the electric heating device is operating in a slow-heating state below the power threshold is acceptable. The voltage sampling parameter is the operating voltage sampling parameter of the electric heating device obtained through real-time sampling during the operation of the electric heating device.

[0042] It can be understood that there is not only one way to obtain the voltage sampling parameters. In one embodiment, it can be achieved through a sampling circuit. The sampling circuit is set between the voltage input terminal of the electric heating equipment and the controller. The sampling circuit is used to periodically obtain the voltage sampling parameters during the operation of the electric heating equipment. The voltage sampling parameters are transmitted to the controller for filtering, analog-to-digital conversion and other operations, or after setting the corresponding circuit for filtering and analog-to-digital conversion, the voltage sampling parameters are sent to the controller to obtain the voltage sampling parameters in digital form, that is, the voltage AD value.

[0043] In another embodiment, the controller may also have a sampling function, and a filter circuit may be directly set at the voltage sampling port of the controller. The filter circuit is connected to the voltage input terminal of the electric heating device. The operating voltage of the high-frequency impurity signal is filtered out through the filter circuit and transmitted to the voltage sampling port of the controller to realize voltage sampling and obtain voltage sampling parameters. Correspondingly, the specific type of filter circuit is not unique. In a more detailed embodiment, a small capacitor (for example, 22pf) and a current-limiting resistor may be used to form an RC filter circuit to filter out voltage spikes transmitted to the controller, so that the controller can sample and obtain accurate voltage sampling values.

[0044] To facilitate understanding of the technical solution of the present application, it can be understood below that the controller has a voltage sampling function, and an RC filter circuit is provided at the voltage sampling port of the controller, and the RC filter circuit is connected to the voltage input port of the electric heating device to realize the voltage acquisition function.

[0045] Step 104 : performing a zero-crossing trend analysis based on the voltage sampling parameters to obtain a zero-crossing detection result of the electric heating device.

[0046] Specifically, zero-crossing detection refers to the detection performed when the voltage waveform passes through zero when transitioning from the positive half-cycle to the negative half-cycle. The corresponding zero position is the zero-crossing point. Since the voltage sampling parameters are located at different positions in the same voltage cycle, the change trends will also have certain differences. Therefore, the technical solution of the present application combines the obtained individual voltage sampling parameters to perform zero-crossing trend analysis, thereby determining whether the electric heating device has experienced zero crossing in the current state and obtaining a zero-crossing detection result.

[0047] Step 106 : If the zero-crossing detection result indicates that a zero-crossing event has occurred, then the slow-heating state is maintained.

[0048] Specifically, there are not only two methods for maintaining a slow heating state. For ease of understanding, the technical solution of this application is explained by controlling the operating state of a drive control circuit in an electric heating device that provides electrical energy to the heating element to maintain a slow heating state. In this case, a chopping process can be performed by turning the power switch in the drive control circuit on and off to maintain a stable slow heating state. Chopping is the process of converting direct current into direct current of another fixed or adjustable voltage.

[0049] The drive control circuit is equipped with a power switch tube. During operation, the power switch tube is turned on and off to transmit electrical energy to the heating device. Specifically, the power switch tube can be controlled by outputting an enable signal. Correspondingly, when the output enable signal enables the power switch tube, the drive signal is allowed to be transmitted to the heating device. When the output disabling signal (i.e., the disable signal) is output to the power switch tube, the power switch tube will not allow the drive signal to be transmitted to the heating device.

[0050] It is understandable that depending on the type of power switch tube (i.e., different types of power switch tubes that are high-level conductive or low-level conductive), when the power switch tube is enabled, the on-off state of the power switch tube will also be different. It can be enabled to make the power switch tube enter the on state and output the drive signal to the heating device; it can also be enabled to make the power switch tube enter the off state, so that the drive signal is output to the heating device. In the actual operation process, it is only necessary to flip the enable signal transmitted to the power switch tube when zero crossing is detected, and finally output the flipped enable signal to the power switch tube, so as to change the on-off state of the power switch tube accordingly, and then decide whether to allow the transmission of the drive signal.

[0051] It should be noted that the specific type of power switch tube is not unique. In one embodiment, it can be a transistor, a MOS tube (Metal-Oxide-Semiconductor) or an IGBT (Insulated Gate Bipolar Transistor), etc. For ease of understanding, IGBT is used for explanation below.

[0052] The technical solution of this embodiment implements zero-crossing detection by performing algorithmic analysis on voltage sampling parameters during the operation of the electric heating device. This eliminates the need for additional zero-crossing detection hardware circuits, significantly reducing hardware circuit costs. Furthermore, the technical solution of this application utilizes a software algorithm to implement zero-crossing detection, thereby avoiding the lifespan of the zero-crossing detection circuit affecting the lifespan of the electric heating device and thereby increasing the lifespan of the electric heating device. Furthermore, the solution can also improve the interference performance of the electric heating device to a certain extent, reducing external interference to the electric heating device during operation.

[0053] The above-described electric heating device control method can perform real-time voltage sampling during the operation of the electric heating device to obtain voltage sampling parameters when the electric heating device is operating at a heating power less than a preset power threshold, that is, when it is in a low-power operating state. Zero-crossing trend analysis of the voltage sampling parameters is then performed to determine whether the electric heating device is in a zero-crossing state. If the electric heating device is in a zero-crossing state, the electric heating device is controlled to maintain a stable slow-heating state. In the above scheme, zero-crossing detection of the electric heating device is directly achieved through analysis of the voltage sampling parameters, eliminating the need for additional hardware circuitry for zero-crossing detection, thereby effectively alleviating the high cost of slow-heating circuits.

[0054] See also Figure 2 In one embodiment, step 104 includes step 202 and step 204 .

[0055] Step 202, performing trend analysis based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment to obtain trend parameters; Step 204, performing zero-crossing analysis based on the current trend parameters and the trend parameters obtained from the previous round of trend analysis to obtain the zero-crossing detection result of the electric heating equipment.

[0056] Specifically, the trend parameter is a parameter that characterizes the changing trend of the current voltage sampling parameter relative to the last collected voltage sampling parameter. The current sampling moment is also the current sampling period, and the last sampling moment is also the last sampling period. During operation of the electric heating device, the controller can collect voltage sampling parameters at a certain sampling period. By combining the voltage sampling parameters collected in the current sampling period with the voltage sampling parameters collected in the last sampling period for trend analysis, the trend parameter corresponding to the current sampling moment, i.e., the current trend parameter, can be obtained.

[0057] The controller also performs trend parameter analysis in real time. Whenever a voltage sampling parameter (as the voltage sampling parameter at the current sampling moment) is obtained, the controller will calculate the voltage parameter obtained and the voltage sampling parameter obtained last time (i.e., the voltage sampling parameter at the previous sampling moment) to obtain a trend parameter. Therefore, when performing zero-crossing detection analysis, the trend parameter obtained by the current trend analysis and the trend parameter obtained by the trend analysis of the voltage sampling parameters at the two adjacent moments before this (i.e., the trend parameter obtained by the previous round of trend analysis) can be combined to perform an analysis and detection of whether zero crossing occurs. For example, in one embodiment, when a jump occurs in the trend parameter detected twice adjacent to each other, it is considered that the electric heating device has crossed zero, and when the trend parameter detected twice adjacent to each other does not jump, it is considered that the electric heating device has not crossed zero.

[0058] The above solution performs trend parameter analysis on voltage sampling parameters obtained twice adjacently, and then implements zero-crossing detection based on the trend parameters obtained from the two adjacent trend analyses, which has the advantage of high detection reliability.

[0059] See also Figure 3 In one embodiment, step 202 includes step 302 and step 304 .

[0060] Step 302 , calculating an initial trend parameter based on the voltage sampling parameter at the current sampling moment and the voltage sampling parameter at the previous sampling moment; Step 304 , performing filtering analysis on the initial trend parameter to obtain a trend parameter.

[0061] Specifically, in the scheme of this embodiment, when calculating with the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment, the calculation results are not directly used as the current trend parameters, but the calculated initial trend parameters need to be filtered before the final trend parameters are obtained, thereby realizing zero-crossing detection analysis.

[0062] This solution performs filtering on the calculated initial trend parameters and performs zero-crossing detection analysis using the filtered trend parameters, which can further improve the accuracy of zero-crossing detection.

[0063] Further, see Figure 4 In one embodiment, the initial trend parameter includes an initial slope parameter, and step 302 includes steps 402 , 404 , and 406 .

[0064] Step 402, obtaining a preset voltage coordinate system; Step 404, extracting the coordinates of the voltage sampling parameter at the current sampling moment in the voltage coordinate system and the coordinates of the voltage sampling parameter at the previous sampling moment in the voltage coordinate system; Step 406, performing slope calculation based on the extracted coordinates to obtain an initial slope parameter.

[0065] Specifically, the voltage coordinate system is constructed by historical voltage sampling parameters. The solution of this embodiment specifically uses a slope parameter to characterize the change trend of two adjacent voltage sampling parameters. In order to obtain the slope of two adjacent voltage sampling parameters, it is necessary to construct a corresponding coordinate system for analysis and calculation. First, the controller will combine the historically acquired voltage sampling parameters, use the sampling times as the horizontal coordinate, and the actual voltage sampling value as the vertical coordinate to build a corresponding plane coordinate system to obtain the voltage coordinate system and store it in the controller. Subsequently, when acquiring voltage sampling parameters, each time a voltage sampling parameter is acquired, it will be updated to the voltage coordinate system, and the corresponding coordinates can be obtained by combining the voltage sampling value size and the sampling times.

[0066] After calculating the initial slope parameter, when calculating, as long as the coordinates of the sampling points at two adjacent sampling times are used, and the difference between the ordinate of the sampling point with a later sampling time and the abscissa difference of the sampling point with an earlier sampling time are compared, the corresponding initial slope parameter can be obtained.

[0067] In the above solution, the slope is calculated by constructing a voltage coordinate system, and the slope parameter is used as the trend parameter for zero-crossing detection analysis. It has the advantages of simple calculation method and high calculation rate, and improves the zero-crossing detection efficiency to a certain extent.

[0068] Please refer to Figure 5 , in one embodiment, step 304 includes step 502.

[0069] Step 502, perform a pass filter on the combined trend parameter obtained from the previous round of trend analysis and the initial trend parameter to obtain the trend parameter.

[0070] Specifically, in the solution of this embodiment, a pass filter is used to perform filter analysis on the initial trend parameter to obtain the trend parameter corresponding to the current sampling time. And during the pass filter process, the final trend parameter obtained when analyzing the trend parameter in the previous round also needs to be combined.

[0071] It can be understood that the specific method of the pass filter is not unique. In a more detailed embodiment, it can be implemented through the following pass filter parameters. Y = r * x n +(1 - r)x n+1 , where 0 < r < 1, Y represents the finally output trend parameter, x n represents the trend parameter obtained from the previous round of trend parameter analysis, and x n+1 represents the initial trend parameter. In the actual analysis process, r can be adjusted according to actual needs. If it is necessary to ensure the data smoothness of the finally obtained trend parameters, the value of r can be slightly larger; if it is necessary to ensure the fast response of the data, the value of r can be appropriately reduced.

[0072] It should be noted that in a more detailed embodiment, the initial trend parameter for filtering using the above pass filter method can be the initial slope parameter. In this embodiment, an array is created for the coordinate system, and for the updated voltage acquisition parameters, the corresponding initial slope parameter is obtained by combining the voltage acquisition parameters updated last time for line drawing calculation. After passing the above pass filter on the initial slope parameter, it is put into the created array for update, so as to realize zero-crossing detection analysis.

[0073] The above scheme combines the trend parameters obtained in the previous round of analysis and performs a filtering on the initial trend parameters to obtain the current corresponding trend parameters, thereby avoiding the influence of sampling fluctuations on the trend analysis results, improving the accuracy of trend parameters, and further improving the accuracy of zero-crossing detection.

[0074] See also Figure 6 In one embodiment, the trend parameter includes a slope parameter, and step 204 includes step 602 .

[0075] Step 602: If the current slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative, it is determined that a zero-crossing event occurs in the electric heating device.

[0076] Specifically, in this embodiment, the trend parameter is used as the slope parameter for explanation. When performing slope analysis and calculation based on the acquired voltage sampling parameters, any inconsistency between the voltage sampling values ​​at two adjacent moments will cause the corresponding slope parameter to be non-zero. Therefore, this embodiment directly determines whether a zero-crossing event has occurred by determining whether the slope parameter has transitioned from negative to positive. This provides greater detection convenience and reliability.

[0077] It should be noted that in a more detailed embodiment, for the convenience of analysis and processing, after performing slope calculation, the controller writes 1 to the storage bit if the slope is positive; and writes zero to the storage bit if the slope is negative, that is, characterizing the slope change of the voltage sampling parameter at adjacent moments in the form of a binary array. Subsequently, when performing zero-crossing detection, it is only necessary to detect whether the adjacent binary arrays have jumped from 0 to 1 to intuitively obtain whether the slope parameter has changed from negative to positive, thereby obtaining the zero-crossing detection result. This storage method greatly reduces the storage space requirement and alleviates the problem of excessive RAM (Random Access Memory) usage in the controller.

[0078] Further, see Figure 7 In one embodiment, step 602 includes steps 702, 704 and 706.

[0079] Step 702, obtaining a time identifier; Step 704, calculating the time interval between the current time identifier and the previous time identifier; Step 706, if the time interval is within a preset time threshold range, determining that a zero-crossing event has occurred in the electric heating device.

[0080] Specifically, the time identifier is the time corresponding to when the slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative. In the solution of this embodiment, when the slope parameter changes from negative to positive, that is, when the array stored in the storage bit of the controller jumps from 0 to 1, it is not directly considered that a zero crossing has occurred. It is necessary to further analyze it based on the time interval between two adjacent 0-1 jumps. The controller has a timing function. Whenever a jump from 0 to 1 is detected in the array, a time identifier is obtained. After two adjacent detections of a jump from 0 to 1 in the array, the two obtained time identifiers are combined for calculation to obtain the time interval between the two jumps. Only when the time interval is within the preset time threshold range will it be considered that a zero crossing has indeed occurred at this time.

[0081] Correspondingly, if the array transitions from 0 to 1 and the interval between the previous transition and the previous transition is within the preset time threshold, the controller sets its internal zero-crossing flag. This means that the state quantity corresponding to the zero-crossing flag is modified to indicate a zero-crossing event. Based on the set state quantity, the controller then implements the corresponding chopping control operation to maintain slow heating. For example, the zero-crossing flag is set to 1.

[0082] It is understood that in another embodiment, if the time interval between the currently acquired time marker and the time marker acquired in the previous round is not within the preset time threshold range, it is considered that no zero-crossing event has occurred. In this case, the zero-crossing flag is in a reset state, and the corresponding state quantity is 0. It should be noted that in other embodiments, the state quantity corresponding to the occurrence of a zero-crossing event can be set to 0, while the state quantity corresponding to the non-occurrence of a zero-crossing event can be set to 1, without specific limitation.

[0083] In the above embodiment, if the time interval is too long, it is determined that the device is in an abnormal power-on state. The zero-crossing flag is reset, and the controller outputs a detection result indicating that no zero crossing has occurred. Accordingly, to facilitate timely detection of subsequent zero crossings, it is necessary to return to the process of acquiring the voltage sampling parameters during the operation of the electric heating device and perform zero-crossing detection and analysis on the acquired voltage sampling parameters. This solution avoids misinterpreting abnormal power-on as a zero crossing, further improving the accuracy of zero-crossing detection.

[0084] See also Figure 8 In one embodiment, before step 102 , the method further includes step 802 .

[0085] Step 802: If the electric heating device enters the continuous heating operation state, the heating power of the electric heating device is obtained and compared with the preset power threshold.

[0086] Specifically, the technical solution of this application requires the electric heating device to enter a low-power, slow-heating state before performing zero-crossing detection and slow-heating control in conjunction with voltage sampling parameters. Otherwise, there is no need to control the on-off switching of the power switch tube for chopping. Therefore, in the solution of this embodiment, it is necessary to first obtain the heating power corresponding to the electric heating device's continuous heating state, compare and analyze it with a preset power threshold, and only when the heating power is less than the preset power threshold will the subsequent zero-crossing detection and analysis operation be initiated.

[0087] It is understood that there is not only one way to detect heating power. The heating power can be calculated by detecting voltage and current. In another embodiment, it can also be achieved by detecting the output signal of the power adjustment button (such as the gear adjustment button) of the electric heating device. During the operation of the electric heating device, the heating power corresponding to each gear is also fixed. Therefore, the actual heating power can be obtained by simply detecting the current gear.

[0088] Further, see Figure 9 In one embodiment, before step 802 , the method further includes steps 902 , 904 and 906 .

[0089] Step 902, when the electric heating device starts running, the electric heating device is powered on and self-tested; Step 904, if the power-on self-test is successful, it is detected whether the heating object of the electric heating device is in the heating area; Step 906, if the heating object is in the heating area, the electric heating device is controlled to enter a continuous heating operation state.

[0090] Specifically, in the solution of this embodiment, when the electric heating equipment is in operation, it first starts to run according to the received power-on instruction. When starting to run, it first needs to perform a self-test. Only when the self-test is successful will the subsequent analysis operations be performed to ensure the startup reliability of the electric heating equipment.

[0091] After the self-test is successful, the controller will further detect the heating object of the electric heating equipment (the specific type is not unique, it can be a pot, etc.). Only when the heating object is in the heating area, the subsequent slow heating control will be effective. If the heating object is not in the heating area, it means that there is no object that needs to be heated at this time, then slow heating is unnecessary, otherwise it will easily cause energy waste.

[0092] It is understood that the self-test function of the electric heating device is not exclusive. In a more detailed embodiment, since subsequent zero-crossing detection depends on the accuracy of voltage sampling parameters, the self-test operation can specifically be used to check whether the sampling function within the controller is functioning properly. In other embodiments, the self-test operation can also be used to check whether other functions of the electric heating device are functioning properly, such as whether the heating device is functioning properly.

[0093] Correspondingly, there is no single method for detecting whether the heated object is in the heating area. In one embodiment, a pressure sensor may be provided in the heating area. When the heated object is in the heating area, the pressure sensor can be pressed to output a pressure parameter. When the heated object is not in the heating area, the pressure sensor will not output a pressure parameter. In another embodiment, an infrared sensor, ultrasonic sensor, etc. may be provided in the heating area to directly detect whether the heated object is in place. The specific method used is not limited here.

[0094] In order to facilitate understanding of the technical solution of the present application, the present application is explained below in conjunction with more detailed embodiments.

[0095] Please refer to Figure 10 After the electric heating device is turned on, it first performs a power-on self-test to check whether the controller's voltage sampling and other functions are functioning properly. If the self-test is successful, it then checks whether the pot is in the heating zone, thus determining whether the pot is in the heating zone. If the pot is in the heating zone, it starts heating continuously. During this heating process, the controller can detect in real time whether the heating power is less than the preset power threshold. If so, it is considered to have entered a low-power slow heating state. To ensure the stability of the slow heating, the controller needs to periodically perform voltage sampling to obtain voltage sampling parameters.

[0096] See also Figure 11 The controller uses the number of voltage sampling as the horizontal coordinate and the voltage sampling parameter as the vertical coordinate to build and store the voltage coordinate system. Every time a voltage sampling parameter is obtained, the voltage sampling parameter will be updated to the voltage coordinate system. The controller then calculates the initial slope parameter (y1-y0) / (x1-x0) using the coordinates (x1, y1) corresponding to the voltage sampling parameter at the current sampling moment and the coordinates (x0, y0) of the voltage sampling parameter at the previous sampling moment. Afterwards, the calculated initial slope parameter xn+1 is substituted into the one-pass filter Y=r*xn+(1-r)xn+1, and combined with the slope parameter xn obtained from the previous round of slope calculation and analysis, filtering is performed to obtain the final slope parameter Y.

[0097] After obtaining the slope parameter, an interval judgment will be performed. According to the trend written into the storage bit, a positive slope parameter will be judged as a positive trend and written as 1, while a negative slope parameter will be judged as a negative trend and written as 0. Then, a zero-crossing analysis will be performed based on the trend of each write storage. If it is detected that the written trend has a jump from 0 to 1, the current time stamp is recorded and compared with the time stamp corresponding to the last 0 to 0 jump to obtain the time interval. If the time interval is within the preset time threshold range, the zero-crossing flag is set, and it is considered that a zero crossing has occurred at this time, that is, it is determined that a zero-crossing event has occurred in the electric heating equipment. In all other cases, it is considered that no zero crossing has occurred, and it is only necessary to return to re-acquire the voltage sampling parameters.

[0098] Finally, when a zero-crossing condition is detected, the controller flips the IGBT enable state in the electric heater's drive control circuit. If the state is enabled after the flip, the IGBT is controlled to output the drive signal, meaning the IGBT enters the on state. If the state is disabled after the flip, the IGBT is controlled to shield the drive signal, meaning the IGBT enters the off state. This chopping is achieved by switching the IGBT on and off, completing a stable slow-heating operation.

[0099] It should be understood that, although the steps in the flowcharts of the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts of the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily to be performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0100] Based on the same inventive concept, embodiments of the present application also provide an electric heating device control device for implementing the above-mentioned electric heating device control method. The solution provided by this device is similar to the solution described in the above-mentioned method. Therefore, the specific limitations of one or more embodiments of the electric heating device control device provided below can be found in the above-mentioned limitations of the electric heating device control method and will not be repeated here.

[0101] See also Figure 12 , an electric heating equipment control device, including: a parameter acquisition module 122, a zero-crossing detection module 124 and a slow fire control module 126.

[0102] The parameter acquisition module 122 is used to obtain the voltage sampling parameters of the electric heating device if the heating power of the electric heating device is less than a preset power threshold; the zero-crossing detection module 124 is used to perform zero-crossing trend analysis based on the voltage sampling parameters to obtain the zero-crossing detection result of the electric heating device; the slow-heat control module 126 is used to maintain the slow-heat heating state if the zero-crossing detection result indicates that a zero-crossing event has occurred.

[0103] In one embodiment, the zero-crossing detection module 124 is also used to perform trend analysis based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment to obtain trend parameters; perform zero-crossing analysis based on the current trend parameters and the trend parameters obtained from the previous round of trend analysis to obtain the zero-crossing detection result of the electric heating equipment.

[0104] In one embodiment, the zero-crossing detection module 124 is further configured to calculate an initial trend parameter based on the voltage sampling parameter at the current sampling moment and the voltage sampling parameter at the previous sampling moment; and perform filtering analysis on the initial trend parameter to obtain the trend parameter.

[0105] In one embodiment, the zero-crossing detection module 124 is also used to obtain a preset voltage coordinate system, which is constructed by historical voltage sampling parameters; extract the coordinates of the voltage sampling parameters at the current sampling moment in the voltage coordinate system and the coordinates of the voltage sampling parameters at the previous sampling moment in the voltage coordinate system; and perform slope calculation based on the extracted coordinates to obtain an initial slope parameter.

[0106] In one embodiment, the zero-crossing detection module 124 is further configured to perform a one-pass filtering on the trend parameter obtained from the previous round of trend analysis and the initial trend parameter to obtain the trend parameter.

[0107] In one embodiment, the zero-crossing detection module 124 is further configured to determine that a zero-crossing event occurs in the electric heating device if the current slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative.

[0108] In one embodiment, the zero-crossing detection module 124 is further configured to obtain a time marker; calculate a time interval between a current time marker and a previous time marker; and determine that a zero-crossing event has occurred in the electric heating device if the time interval is within a preset time threshold.

[0109] See also Figure 13 In one embodiment, before the parameter acquisition module 122 , the electric heating equipment control device further includes a heating power comparison module 132 .

[0110] The heating power comparison module 132 is used to obtain the heating power of the electric heating device if the electric heating device enters the continuous heating operation state, and compare and analyze it with a preset power threshold.

[0111] See also Figure 14 In one embodiment, the electric heating device control device further includes a detection module 142 before the heating power comparison module 132. The detection module 142 is configured to perform a power-on self-test on the electric heating device when the electric heating device is started. If the power-on self-test is successful, the detection module 142 detects whether the heating object of the electric heating device is within the heating zone. If the heating object is within the heating zone, the detection module 142 controls the electric heating device to enter a continuous heating operation state.

[0112] The above-mentioned electric heating equipment control device is capable of real-time voltage sampling during the operation of the electric heating equipment, obtaining voltage sampling parameters, when the electric heating equipment is operating at a heating power less than a preset power threshold, that is, when it is in a low-power operating state. Zero-crossing trend analysis of the voltage sampling parameters is then performed to determine whether the electric heating equipment is in a zero-crossing state. If the electric heating equipment is in a zero-crossing state, the electric heating equipment is controlled to maintain a stable slow-heating state. In the above scheme, zero-crossing detection of the electric heating equipment is directly achieved through analysis of the voltage sampling parameters, eliminating the need for additional hardware circuitry for zero-crossing detection, thereby effectively alleviating the high cost of slow-heating circuits.

[0113] See also Figure 15 A control system for an electric heating device includes a filter circuit 152, a controller 154 and a drive control circuit 156. The filter circuit 152 is connected to the controller 154, and the controller 154 is connected to the drive control circuit 156. The filter circuit 152 filters the working voltage of the electric heating device and transmits it to the controller 154. Based on the filtered working voltage and using the above-mentioned electric heating device control method, the controller 154 outputs an enable signal to the drive control circuit 156 to adjust the operating state of the drive control circuit 156 and maintain a slow heating state.

[0114] Specifically, the electric heating device control method is as shown in the above-mentioned embodiments and the accompanying drawings, and will not be described in detail here. The controller 154 has a sampling function, and a filter circuit 152 is directly set at the voltage sampling port of the controller 154. The filter circuit 152 is connected to the voltage input terminal of the electric heating device. The working voltage of the high-frequency impurity signal is filtered out through the filter circuit 152 and transmitted to the voltage sampling port of the controller 154 to realize voltage sampling and obtain voltage sampling parameters. Correspondingly, the specific type of the filter circuit 152 is not unique. In a more detailed embodiment, a small capacitor (for example, 22pf, etc.) and a current-limiting resistor can be used to form an RC filter circuit 152 to filter out the voltage spikes transmitted to the controller 154, so that the controller 154 can sample and obtain accurate voltage sampling values.

[0115] The above-mentioned electric heating equipment control system is capable of sampling the voltage of the electric heating equipment in real time during operation to obtain voltage sampling parameters when the electric heating equipment is operating at a heating power lower than a preset power threshold, that is, when it is in a low-power operating state. Zero-crossing trend analysis of the voltage sampling parameters is then performed to determine whether the electric heating equipment is in a zero-crossing state. If the electric heating equipment is in a zero-crossing state, the electric heating equipment is controlled to maintain a stable slow-heating state. In the above scheme, zero-crossing detection of the electric heating equipment is directly implemented through analysis of the voltage sampling parameters, eliminating the need for additional hardware circuitry for zero-crossing detection, thereby effectively alleviating the high cost of slow-heating circuits.

[0116] An electric heating device comprises the above-mentioned electric heating device control system.

[0117] Specifically, the electric heating equipment control system is as shown in the above-mentioned embodiments and the accompanying drawings, and will not be described in detail here. When the electric heating equipment is operating at a heating power less than a preset power threshold, that is, when it is in a low-power operating state, it can perform real-time voltage sampling during the operation of the electric heating equipment to obtain voltage sampling parameters. After that, a zero-crossing trend analysis is performed on the voltage sampling parameters to determine whether the electric heating equipment is in a zero-crossing state. When the electric heating equipment is in a zero-crossing state, the electric heating equipment is controlled to maintain a stable slow-heating state. In the above scheme, the zero-crossing detection of the electric heating equipment is directly achieved through the analysis of the voltage sampling parameters, and there is no need to set up an additional hardware circuit for zero-crossing detection, thereby effectively alleviating the problem of high cost of the slow-heating circuit.

[0118] It is understood that the specific type of electric heating device is not unique. In a more detailed embodiment, the electric heating device can be an electromagnetic heating device. More specifically, the electromagnetic heating device can also include an IH rice cooker or an electromagnetic cooker, an induction heating furnace, etc.

[0119] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for controlling an electric heating device, characterized in that: include: If the heating power of the electric heating device is less than the preset power threshold, obtaining the voltage sampling parameter of the electric heating device; Performing a zero-crossing trend analysis based on the voltage sampling parameters to obtain a zero-crossing detection result of the electric heating device; If the zero-crossing detection result indicates that a zero-crossing event has occurred, maintaining the slow-heating state; The performing of zero-crossing trend analysis based on the voltage sampling parameters to obtain the zero-crossing detection result of the electric heating equipment includes: performing trend analysis based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment to obtain trend parameters; performing zero-crossing analysis based on the current trend parameters and the trend parameters obtained from the previous round of trend analysis to obtain the zero-crossing detection result of the electric heating equipment; the trend parameters are parameters that characterize the changing trend of the voltage sampling parameters at the current sampling moment relative to the voltage sampling parameters at the previous sampling moment.

2. The electric heating equipment control method according to claim 1, characterized in that: The step of performing trend analysis based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment to obtain trend parameters includes: The initial trend parameter is calculated based on the voltage sampling parameter at the current sampling moment and the voltage sampling parameter at the previous sampling moment; Perform filtering analysis on the initial trend parameter to obtain a trend parameter.

3. The electric heating equipment control method according to claim 2, characterized in that: The initial trend parameters include initial slope parameters; The initial trend parameter is calculated based on the voltage sampling parameter at the current sampling moment and the voltage sampling parameter at the previous sampling moment, including: Obtaining a preset voltage coordinate system, where the voltage coordinate system is constructed by historical voltage sampling parameters; Extracting the coordinates of the voltage sampling parameter at the current sampling moment in the voltage coordinate system and the coordinates of the voltage sampling parameter at the previous sampling moment in the voltage coordinate system; The slope is calculated based on the extracted coordinates to obtain the initial slope parameters.

4. The electric heating equipment control method according to claim 2 or 3, characterized in that: The filtering analysis of the initial trend parameter to obtain the trend parameter includes: The trend parameters obtained from the previous round of trend analysis are combined with the initial trend parameters to perform a one-pass filtering to obtain the trend parameters.

5. The electric heating device control method according to any one of claims 1 to 3, characterized in that: The trend parameter includes a slope parameter; The zero-crossing analysis is performed based on the current trend parameter and the trend parameter obtained from the previous round of trend analysis to obtain the zero-crossing detection result of the electric heating device, including: If the current slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative, it is determined that a zero-crossing event occurs in the electric heating device.

6. The electric heating equipment control method according to claim 5, characterized in that: If the current slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative, determining that a zero-crossing event occurs in the electric heating device includes: Obtaining a time mark, where the time mark is the time corresponding to when the slope parameter is positive and the slope parameter obtained in the previous round of trend analysis is negative; Calculate the time interval between the current time stamp and the previous time stamp; If the time interval is within a preset time threshold range, it is determined that a zero-crossing event occurs in the electric heating device.

7. The electric heating device control method according to any one of claims 1 to 3, characterized in that: If the heating power of the electric heating device is less than the preset power threshold, before obtaining the voltage sampling parameter of the electric heating device, the method further includes: If the electric heating device enters a continuous heating operation state, the heating power of the electric heating device is obtained and compared with a preset power threshold value for analysis.

8. The electric heating equipment control method according to claim 7, characterized in that: If the electric heating device enters the continuous heating operation state, the method further includes obtaining the heating power of the electric heating device and comparing and analyzing the power with a preset power threshold. When the electric heating device starts to operate, performing a power-on self-test on the electric heating device; If the power-on self-test is successful, then detecting whether the heating object of the electric heating device is in the heating area; If the heating object is in the heating area, the electric heating device is controlled to enter a continuous heating operation state.

9. An electric heating equipment control device, characterized in that: include: a parameter acquisition module, configured to acquire a voltage sampling parameter of the electric heating device if the heating power of the electric heating device is less than a preset power threshold; a zero-crossing detection module, configured to perform a zero-crossing trend analysis based on the voltage sampling parameters to obtain a zero-crossing detection result of the electric heating device; a slow-heat control module, configured to maintain a slow-heat heating state if the zero-crossing detection result indicates that a zero-crossing event has occurred; The zero-crossing detection module is further configured to perform trend analysis based on the voltage sampling parameters at the current sampling moment and the voltage sampling parameters at the previous sampling moment to obtain trend parameters; Performing a zero-crossing analysis based on the current trend parameter and the trend parameter obtained from the previous round of trend analysis to obtain a zero-crossing detection result of the electric heating device; The trend parameter is a parameter that characterizes a change trend of the voltage sampling parameter at the current sampling moment relative to the voltage sampling parameter at the previous sampling moment.

10. An electric heating equipment control system, characterized in that: It includes a filtering circuit, a controller and a drive control circuit, the filtering circuit is connected to the controller, the controller is connected to the drive control circuit, the filtering circuit filters the working voltage of the electric heating equipment and transmits it to the controller, and the controller outputs an enable signal to the drive control circuit based on the filtered working voltage and adopts the electric heating equipment control method according to any one of claims 1-8 to adjust the operating state of the drive control circuit and maintain a slow heating state.

11. An electric heating device, characterized in that: Including the electric heating equipment control system according to claim 10.

12. The electric heating device according to claim 11, characterized in that The electric heating device is an electromagnetic heating device.

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