Heating system fault prediction method and device, and electric water heater

Abstract

The embodiment of the present application discloses a heating system fault prediction method and device and an electric water heater. The heating system comprises an electric parameter detector and at least one heating unit. The heating unit comprises a heating element and a first switch for controlling the start and stop of the heating element. The electric parameter detector is used to detect the electric parameter of the power supply line of the heating element. The method comprises: when a predetermined condition is met, performing a first operation of disconnecting the first switch; obtaining the time length elapsed when the change of the electric parameter detected by the electric parameter detector from the performance of the first operation exceeds a preset value; and generating a fault prediction signal when the time length is not less than a first preset time length. Through the embodiment of the present application, the possibility of switch failure can be predicted in advance, so that maintenance personnel can maintain or service the switch in time before the switch really fails, thereby prolonging the service life of the heating system.

Description

Technical Field

[0001] This application relates to the field of fault diagnosis, and in particular to a method, apparatus and electric water heater for predicting faults in a heating system. Background Technology

[0002] The heating element of an electric water heater is usually controlled by a switch. For electrical devices like switches, the proper closing and opening of their contacts is crucial to ensuring the normal operation of the heating element.

[0003] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0004] In related technologies, it is possible to detect whether a switch has malfunctioned by monitoring changes in current in the circuit. However, there is currently no method for predicting switch malfunctions, so it is not possible to predict in advance whether a switch is at risk of failure.

[0005] To address at least one of the aforementioned problems, embodiments of this application provide a heating system fault prediction method, apparatus, and electric water heater.

[0006] The specific technical solution of this application embodiment is as follows:

[0007] According to a first aspect of the embodiments of this application, a method for predicting faults in a heating system is provided. The heating system includes an electrical parameter detector and at least one heating unit. The heating unit includes a heating element and a first switch for controlling the start and stop of the heating element. The electrical parameter detector is used to detect the electrical parameters of the power supply line of the heating element. The method includes:

[0008] When predetermined conditions are met, the first operation of disconnecting the first switch is performed;

[0009] The time elapsed from the execution of the first operation to the point when the change in electrical parameters detected by the electrical parameter detector exceeds a preset value is obtained. When the time elapsed is not less than a first preset time elapsed, a fault prediction signal is generated.

[0010] Furthermore, the heating system also includes a thermostat for detecting the temperature of the heated water, which satisfies the predetermined condition when the water temperature reaches the first preset water temperature.

[0011] Furthermore, the electrical parameter detector includes a current transformer for detecting the current in the power supply trunk of the heating element.

[0012] Furthermore, the first preset duration is the time required for the first switch to go from the closed state to the first switch automatically opening normally.

[0013] Furthermore, when the duration is not less than a first preset duration, generating a fault prediction signal includes:

[0014] When the duration is not less than a first preset duration and not greater than a second preset duration, the first switch is determined to be abnormally disconnected and the fault prediction signal is generated, wherein the second preset duration is greater than the first preset duration.

[0015] Furthermore, the fault prediction signal includes a fault warning signal and / or a system maintenance signal.

[0016] Furthermore, the method also includes:

[0017] If the electrical parameter detector does not detect a change in electrical parameters exceeding a preset value within a second preset duration, it is determined that the first switch has stuck and a fault signal is generated, wherein the second preset duration is longer than the first preset duration.

[0018] Furthermore, the heating system also includes a second switch disposed on the power supply line of the heating unit and connected in series with the first switch;

[0019] The second preset duration is a predetermined value or the second preset duration is not greater than the time required from the execution of the first operation to the opening of the second switch.

[0020] Furthermore, the heating system also includes a second switch connected in series with the first switch;

[0021] The second preset duration is a predetermined value or the second preset duration is not greater than the time required from the execution of the first operation to the opening of the second switch.

[0022] Furthermore, after performing the first operation, if it is detected that the water temperature heated by the heating system exceeds the second preset water temperature, the second switch is disconnected, and the second preset water temperature is greater than the first preset water temperature.

[0023] Furthermore, the heating system also includes a third switch for controlling the opening and closing of the second switch. When the water temperature after being heated by the heating system exceeds a third preset water temperature, the third switch switches from the on state to the off state.

[0024] Furthermore, when it is determined that the first switch is stuck, the method further includes: disconnecting the second switch.

[0025] Furthermore, the first switch and / or the second switch include an AC contactor.

[0026] According to a second aspect of the embodiments of this application, a heating system fault prediction device is provided, including a controller configured to perform the heating system fault prediction method described in the first aspect.

[0027] According to a third aspect of the embodiments of this application, an electric water heater is provided, comprising:

[0028] A heating system includes an electrical parameter detector and at least one heating unit, the heating unit including a heating element and a first switch for controlling the start and stop of the heating element, the electrical parameter detector being used to detect the electrical parameters of the power supply line of the heating element;

[0029] The heating system fault prediction device described in the second aspect;

[0030] The inner liner, wherein the heating element is used to heat the water in the inner liner.

[0031] Furthermore, the electrical parameter detector includes a current transformer for detecting the current in the power supply trunk of the heating element.

[0032] Furthermore, the heating system also includes a thermostat electrically connected to the controller for detecting the water temperature after heating. When the thermostat detects that the water temperature has reached a first preset water temperature, the controller performs a first operation of disconnecting the first switch.

[0033] Furthermore, the heating system also includes: a second switch disposed on the power supply line of the heating unit and connected in series with the first switch;

[0034] After the controller performs the first operation, when the thermostat detects that the water temperature exceeds the second preset water temperature, the controller performs the second operation of disconnecting the second switch.

[0035] Furthermore, the first switch and / or the second switch include an AC contactor.

[0036] Furthermore, the heating system also includes a third switch for controlling the opening and closing of the second switch, the third switch switching between an on state and an off state according to temperature changes.

[0037] Furthermore, the third switch is a high-temperature limit switch. When the water temperature after being heated by the heating system exceeds a third preset water temperature, the third switch switches from the on state to the off state.

[0038] The beneficial effect of this application embodiment is that: the time elapsed from the execution of the first operation to the time when the change of electrical parameters detected by the electrical parameter detector exceeds a preset value is obtained, and when the time is not less than the first preset time, a fault prediction signal is generated. Thus, the possibility of switch failure can be predicted in advance, so that maintenance personnel can maintain or repair the switch in time before the switch actually fails, thereby extending the service life of the heating system.

[0039] Specific embodiments of this application are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of this application can be adopted. It should be understood that the embodiments of this application are not limited in scope. Within the spirit and scope of the appended claims, embodiments of this application include many changes, modifications, and equivalents. Features described and / or shown for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments. Attached Figure Description

[0040] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this application in any way. Furthermore, the shapes and scales of the components in the drawings are merely illustrative to aid in understanding this application and do not specifically limit the shapes and scales of the components. Those skilled in the art, guided by the teachings of this application, can select various possible shapes and scales to implement this application according to specific circumstances.

[0041] Figure 1 This is a schematic diagram of the heating unit structure in an embodiment of this application;

[0042] Figure 2 This is a schematic diagram of the fault prediction method in the embodiments of this application;

[0043] Figure 3 This is a schematic diagram of the heating unit in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the fault prediction method in the embodiments of this application;

[0045] Figure 5 This is a schematic diagram of the fault prediction method in the embodiments of this application;

[0046] Figure 6 This is a schematic diagram of the fault prediction method in the embodiments of this application;

[0047] Figure 7 This is a schematic diagram of the fault prediction device in the embodiments of this application;

[0048] Figure 8 This is a schematic diagram of the electric water heater configuration in an embodiment of this application;

[0049] Figure 9 This is a schematic diagram of the heating system structure in an embodiment of this application. Detailed Implementation

[0050] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate this application and are not intended to limit the scope of the present invention. After reading this application, any modifications of this application by those skilled in the art in various equivalent forms fall within the scope defined by the appended claims.

[0051] In the embodiments of this application, the terms "first," "second," etc., are used to distinguish different elements by name, but do not indicate the spatial arrangement or chronological order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one or more of the terms listed in association and all combinations thereof. The terms "comprising," "including," "having," etc., refer to the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] First aspect of the embodiments

[0054] An embodiment of the first aspect of this application provides a method for predicting faults in a heating system. The heating system includes an electrical parameter detector and at least one heating unit. The heating unit includes a heating element and a first switch for controlling the start and stop of the heating element. The electrical parameter detector is used to detect the electrical parameters of the power supply line of the heating element. Figure 1 and Figure 3 This is a schematic diagram of the heating unit structure according to an embodiment of this application, as shown below. Figure 1 and Figure 3As shown, the heating system includes at least one (hereinafter referred to as N, for example, N=4) heating unit 101, where N is an integer greater than or equal to 1. By providing operating current to the heating unit, the heating unit heats up, thereby realizing the heating function. The operating current of the heating system can be single-phase power supply current, two-phase power supply current, or three-phase power supply current, etc., and this application embodiment is not limited to this. Each heating unit includes a heating element 102 and a first switch 103 that controls the start and stop of the heating element. For example, the heating element 102 can be a heating rod, and the first switch 103 can be an AC contactor. The heating element being in the running state or the on state means that the first switch controlling the heating element in the heating unit is in the conducting state, and the heating element being in the stopped state or the off state means that the first switch controlling the heating element in the heating unit is in the off state.

[0055] In some embodiments, each heating unit may include a first switch and one or more heating elements. For example, when the operating current is a single-phase supply current, the heating system contains only one phase wire, such as... Figure 1 As shown, for a heating unit, it includes a first switch and a heating element; when the operating current is a three-phase power supply current, as... Figure 3 As shown, the heating system includes three phase lines: U-phase, V-phase, and W-phase. That is, for each of these three phase lines, a heating unit includes a first switch and heating elements for three different phase line branches. The first switch can simultaneously control the start and stop of the heating elements on all three phase lines. Examples of each phase line are not listed here; the following will use... Figure 1 This example illustrates the fault detection process.

[0056] It should be noted that in the above example, each phase line of each heating unit includes one heating element, but the embodiments of this application are not limited to this, and may also include at least two heating elements connected in series, etc., which will not be elaborated here.

[0057] In some embodiments, the electrical parameter detector is used to detect the electrical parameters of the power supply line of the heating element, which may be current parameters or voltage parameters. For example, the electrical parameter detector includes a current transformer (also called a current sensor) for detecting the current in the power supply trunk of the heating element. The current transformer is connected in series in the trunk of the phase line to obtain the current value of the trunk. However, this embodiment is not limited to this. The electrical parameter detector also includes a voltage detector for detecting the voltage across the heating element. The voltage detector may be connected in parallel across the heating element. The position and connection relationship of the electrical parameter detector will be described in the embodiments described later. The following description uses a current transformer as the electrical parameter detector.

[0058] Figure 2 This is a schematic diagram of the fault prediction method according to an embodiment of this application, such as... Figure 2 As shown, the method includes:

[0059] 201. When a predetermined condition is met, perform the first operation of disconnecting the first switch;

[0060] 202. Obtain the time elapsed from the execution of the first operation to the time when the change in electrical parameters detected by the electrical parameter detector exceeds a preset value. When the time elapsed is not less than a first preset time elapsed, generate a fault prediction signal.

[0061] In some embodiments, the heating system can be used for heating, and when it completes a predetermined heating task, or in certain operating states, it can perform the fault prediction and determination. For example, the heating system can be used in an electric water heater to heat water, and when the heated water temperature reaches a first preset water temperature, the predetermined condition is met. For example, the first preset water temperature can be a target water temperature set by the user. That is, when the target water temperature is reached, the first operation of disconnecting the first switch is performed, thereby enabling fault prediction and determination without affecting the user's normal water use. However, this embodiment is not limited to this. Meeting the predetermined condition may also include powering on (starting power supply), or meeting the predetermined condition may also include the cumulative running time of the heating element exceeding a preset time, or a preset period between the execution interval of the previous fault prediction, etc., which will not be exemplified here.

[0062] In some embodiments, the heating system may further include a thermostat for detecting the temperature of the heated water. The thermostat detects the water temperature, and when the water temperature reaches a first preset temperature, the predetermined condition is met, and a first operation of disconnecting the first switch is performed; that is, the thermostat can control the disconnection of the first switch. The location and connection of the thermostat will be described in the embodiments described later.

[0063] In some embodiments, the heating system may further include a controller and a first relay (the location and connection relationship will be described in the embodiments below). The controller and the first switch form a first circuit (e.g., the controller and the first switch are connected by a wire to form a first circuit). The first relay and the aforementioned thermostat are disposed on the first circuit to control the on or off of the first switch. The number of the first relays corresponds to the number of the first switches, that is, one first relay corresponds to one first switch. The corresponding first relays and first switches are connected in series. The thermostat can report the detected water temperature to the controller in real time or periodically. When the controller determines that the reported water temperature has reached a first preset water temperature, it determines that the condition is met and executes a first operation. The first operation includes: the controller sending a disconnect signal to the first relay corresponding to the first switch. The first relay can be regarded as a relay. After the first relay is disconnected, it is equivalent to stopping the power supply to the first switch, thereby causing the first switch to disconnect.

[0064] In some embodiments, taking an AC contactor as an example, when the first switch is functioning correctly, if power is supplied to the first switch, its contacts will engage the coil, thus completing the circuit. If power is stopped, the contacts will no longer engage the coil, and the first switch will open. After power is stopped, a certain time TH is required from the state where the contacts engage the coil (closed state) to the state where the contacts no longer engage the coil (automatic disconnection state). In other words, TH is the time required for the first switch to automatically disconnect from its closed state. However, if the first switch malfunctions, for example, when the contacts are stuck together, if power is stopped, the contacts will still engage the coil, and the first switch will not automatically disconnect. In the embodiments of this application, "automatic disconnection of the first switch" refers to the time from the contact engaging the coil to the contact no longer engaging the coil after power is stopped due to the disconnection of the first relay, indicating that the first switch has automatically disconnected.

[0065] The inventors discovered that when the first switch is likely to fail or is about to fail, if the power supply to the first switch is stopped, the time required for the first switch to transition from the state where the contacts engage the coil to the state where the contacts cannot engage the coil will no longer be TH. Therefore, fault prediction can be made based on this time. The following is a detailed explanation.

[0066] In some embodiments, in 202, the time T elapsed from the execution of the first operation to when the change in the electrical parameter detected by the electrical parameter detector exceeds a preset value is obtained. When the time T is not less than a first preset time, a fault prediction signal is generated. For example, the first preset time may be TH or slightly greater than TH, and this application does not limit it thereto.

[0067] In some embodiments, after the first switch is opened, compared to the closed state of the first switch, the load in the circuit can be considered to increase, resulting in a decrease in the main circuit current value (for example, when the first switch is open, the branch where the heating element is located is in an open circuit state, the heating element stops operating, thereby increasing the load resistance in the circuit, and thus causing a decrease in the main circuit current). Therefore, after the power supply to the first switch is stopped, if the change in the electrical parameters detected by the electrical parameter detector exceeds a preset value, for example, if the main circuit current value changes and the change exceeds the preset value, it indicates that the first switch is open. It should be noted that the obtained main circuit current value can also be compensated and corrected, and then the change in the compensated and corrected main circuit current value can be compared with the preset value. Examples will not be given here. The preset value (second preset value) can be less than or equal to the difference between the main circuit current value when the first switch is closed and the main circuit current value when the first switch is open.

[0068] In some embodiments, after performing the first operation, timing begins, or the moment of performing the first operation is taken as the starting point. It is determined whether a change in the main circuit current exceeding a preset value is detected. If a change in the main circuit current exceeding the preset value is detected, as mentioned above, it indicates that the first switch has opened. Then, the time elapsed from the starting point to the detection of the main circuit current exceeding the preset value is determined. If the time elapsed T is less than a first preset time elapsed, it indicates that the first switch has automatically opened normally. If the time elapsed T is not less than the first preset time elapsed, a fault prediction signal, a fault warning signal, and / or a system maintenance signal is generated. That is, if the time elapsed T is not less than the first preset time elapsed, it means that the automatic opening of the first switch actually took longer than the time required for the first switch to switch from the closed state to the normal automatic opening state, but the first switch still automatically opened (without fault). This further indicates that the first switch may be about to fail or is about to fail, thus achieving fault prediction. Therefore, if the time elapsed T is not less than the first preset time elapsed, the possibility of the first switch failing can be predicted. In addition, fault prediction signals include fault warning signals and / or system maintenance signals. These fault prediction signals can remind maintenance personnel to maintain or service the switch in a timely manner before the switch actually fails.

[0069] In some embodiments, the heating system further includes a second switch 104 disposed on the power supply line of the heating unit and connected in series with the first switch; the controller and the second switch 104 form a second circuit (for example, the controller and the second switch are connected by a wire to form a second circuit). By setting a dual switch to control the start and stop of the heating element, the second switch can be disconnected for circuit protection when the first switch may be about to fail or has failed. The heating system may also include a second relay (the position and connection relationship will be described in the embodiments below). The second relay is disposed on the second circuit, and the number of second relays corresponds to the number of second switches, that is, one second relay corresponds to one second switch, and the corresponding second relay and second switch are connected in series. However, the embodiments of this application are not limited to this, and only one second relay may be set to control the conduction and disconnection of all second switches.

[0070] The following explains how to control the second switch to be on and off.

[0071] In some embodiments, after performing the first operation, if the water temperature heated by the heating system is detected to exceed a second preset water temperature, the second switch is disconnected. The second preset water temperature is greater than the first preset water temperature. After the first operation of disconnecting the first switch is performed, as mentioned above, if the first switch is about to malfunction or has already malfunctioned, the automatic disconnection time may be longer than normal, or it may even fail to disconnect automatically. In this case, the heating element controlled by the first switch remains on, continuously heating the water (e.g., an electric water heater), causing the water temperature to continue to rise. The thermostat continuously monitors and reports the water temperature to the controller. When the controller determines that the water temperature reported by the thermostat has reached the second preset water temperature, it sends a disconnection signal to the second relay corresponding to the second switch. The second relay can be considered a relay; after the second relay disconnects, it is equivalent to stopping the power supply to the second switch, thus causing the second switch to disconnect. Since the second switch, the first switch, and the heating element are connected in series, the disconnection of the second switch can also control the heating element to stop operating. This protects the circuit, preventing overheating and damage to the heating element.

[0072] In the above example, the opening of the second switch is actively controlled by the controller, but this application embodiment does not limit this. The heating system may also include a third switch for controlling the opening and closing of the second switch. The third switch is set in the second circuit. When the water temperature after being heated by the heating system exceeds a third preset water temperature, the third switch switches from the on state to the off state. The third preset water temperature may be greater than or equal to the second preset water temperature, and this application embodiment does not limit this. The third switch may be a high-temperature limit switch, and its specific implementation can refer to the prior art. For example, the high-temperature limit switch may be a bimetallic strip temperature switch. When the water temperature exceeds the third preset water temperature, the thermal expansion coefficient of one metal strip is greater than that of the other metal strip, causing the entire bimetallic strip to bend to one side, thereby opening the third switch. After the third switch opens, the second switch connected in series with it is de-energized and therefore also opens. That is to say, in the above method, the opening of the second switch is passively triggered by the third switch. The position and connection relationship of the third switch will be described in the following embodiments.

[0073] The inventors discovered that in related technologies, when the third switch and the thermostat are placed in the same circuit, if the first switch fails, even if the third switch is disconnected, the first switch cannot be disconnected. Therefore, the heating element controlled by the first switch remains on, continuously heating the water (e.g., an electric water heater), causing the water temperature to continue to rise. As shown in the above embodiment, the thermostat and the third switch are respectively placed in different circuits of the first and second switches. This allows for circuit protection by disconnecting the second circuit via the third switch when the first switch is about to fail or has already failed, preventing overheating and damage to the heating element. Furthermore, the third switch also ensures the effective disconnection of the second circuit; even if the controller fails to reliably and promptly disconnect the second switch, the second switch can still be disconnected via the third switch.

[0074] In some embodiments, in step 202, to further improve the accuracy of fault prediction and increase the detection speed, the first switch can be determined to have automatically disconnected abnormally when the duration T is not less than a first preset duration and not greater than a second preset duration, and the fault prediction signal can be generated, wherein the second preset duration is longer than the first preset duration. The second preset duration is a predetermined value. For example, the second preset duration can be a predetermined value, which is the duration required for the first switch to switch from a closed state to automatic disconnection when there is a small amount of local adhesion, as obtained from a pre-experimental study; that is, if no change in the main circuit current exceeding the preset value is detected within the first preset duration, but a change in the main circuit current exceeding the preset value is detected within the period from the first preset duration to the second preset duration, it indicates that the first switch may be about to fail or is about to fail, thus achieving fault prediction. For example, if the first switch is about to malfunction or is about to malfunction, including if the first switch is partially stuck, then the first switch is not considered to be malfunctioning because it is only partially stuck (as mentioned before, a malfunction means that when power is stopped to the first switch, the contact will still engage the coil, and the first switch cannot automatically disconnect). After power is stopped to the first switch, the first switch will still automatically disconnect. However, it is precisely because of this partial sticking that the time it takes for the first switch to automatically disconnect is longer than the time it takes for it to automatically disconnect normally, but it will not exceed the second preset time.

[0075] The above example uses a second preset duration as an example. This second preset duration can also be related to the second switch. For example, the second preset duration is not greater than the time required from executing the first operation to the second switch being turned off. As mentioned earlier, after the first operation of turning off the first switch is executed, if the first switch is about to malfunction or malfunctions, the automatic disconnection time will be longer than the normal TH, or it may even fail to disconnect automatically. In this case, the heating element controlled by the first switch remains on, continuously heating the water (e.g., an electric water heater), which will cause the water temperature to continue to rise. When the water temperature exceeds the second preset water temperature, the controller controls the second switch to be turned off. When the water temperature exceeds the third preset water temperature, the third switch is turned off to passively turn off the second switch. The turning off of the second switch will also cause the change in electrical parameters detected by the electrical parameter detector to exceed the preset value. The change in electrical parameters detected by the electrical parameter detector exceeding the preset value is due to the second switch being open, not the first switch automatically opening. In other words, if the change in electrical parameters detected by the electrical parameter detector exceeds the preset value but the second switch has not yet been opened (the second switch has not yet been triggered to open), it indicates that the first switch is automatically opening. That is, if the duration T exceeds the first preset duration but does not exceed the duration required from the execution of the first operation to the opening of the second switch, it indicates that the change in electrical parameters detected by the electrical parameter detector exceeds the preset value due to the automatic opening of the first switch. However, if the duration T exceeds the first preset duration, it indicates that the automatic opening is abnormal and the fault prediction signal needs to be generated.

[0076] As can be seen from the above embodiments, when there is a second switch in the circuit, the change of electrical parameters exceeding the preset value is not necessarily caused by the automatic disconnection of the first switch, but may also be caused by the disconnection of the second switch. Therefore, relying solely on the change of electrical parameters and the first preset duration is insufficient to accurately predict whether the automatic disconnection of the first switch is abnormal. It is also necessary to combine the second preset duration to accurately predict whether the automatic disconnection of the first switch is abnormal.

[0077] In some embodiments, in addition to predicting faults, fault determination can also be performed, and the method further includes:

[0078] 203. If the electrical parameter detector does not detect a change in electrical parameters exceeding a preset value within a second preset time period, it is determined that the first switch has stuck, and a fault signal is generated. In other words, if the first switch does not automatically disconnect within the second preset time period, and therefore the electrical parameter detector does not detect a change in electrical parameters exceeding the preset value, it is determined that the first switch has malfunctioned, i.e., stuck. Alternatively, for example, if the second preset time period is not greater than (e.g., equal to) the time required for the first operation to the second switch to disconnect, and the electrical parameter detector detects a change in electrical parameters exceeding the preset value within a time period exceeding the second preset time period, it indicates that the electrical parameter detector detected the change in electrical parameters due to the second switch disconnecting, and the first switch did not automatically disconnect within the time period exceeding the second preset time period. This can also be interpreted as the first switch sticking, and a fault signal is generated.

[0079] In some embodiments, when it is determined that the first switch is stuck, the method further includes: disconnecting the second switch. In this embodiment, it is not necessary to control the opening and closing of the second switch according to a second preset water temperature and a third preset water temperature. Instead, when it is determined that the first switch is stuck, the controller sends a disconnect signal to the second relay corresponding to the second switch. After the second relay is disconnected, it is equivalent to stopping the power supply to the second switch, thereby causing the second switch to disconnect. This further enhances the protective measure of disconnecting heating, stopping the unit's heating, protecting the heating system, and extending the service life of the heating system.

[0080] Figure 4 This is a schematic diagram of the fault prediction method according to an embodiment of this application, such as... Figure 4 As shown, for Figure 1 In the scenario described, the method includes:

[0081] 401. When the thermostat detects that the water temperature exceeds the first preset water temperature, it performs the first operation of disconnecting the first switch;

[0082] 402. Within a first preset time period starting from the first operation of disconnecting the first switch, determine whether the change in electrical parameters detected by the electrical parameter detector exceeds a preset value. If it does, proceed to 403; otherwise, proceed to 404.

[0083] 403, confirming that the first switch is normal and without fault;

[0084] 404. After the first operation of disconnecting the first switch is executed, if the first preset time period has exceeded, but within the second preset time period, it is determined whether the change of electrical parameters detected by the electrical parameter detector exceeds the preset value. If it exceeds, proceed to 405; otherwise, proceed to 406.

[0085] 405, Generate fault prediction signal;

[0086] 406. Confirm that the first switch is stuck. Disconnect the second switch.

[0087] Figure 5 This is a schematic diagram of the fault prediction method according to an embodiment of this application, such as... Figure 5 As shown, for Figure 1 In the scenario described, the method includes:

[0088] 501, when the thermostat detects that the water temperature exceeds the first preset water temperature, the first operation of disconnecting the first switch is performed;

[0089] 502. Within a first preset time period starting from the first operation of disconnecting the first switch, determine whether the change in electrical parameters detected by the electrical parameter detector exceeds a preset value. If it does, proceed to 503; otherwise, proceed to 504.

[0090] 503, confirming that the first switch is normal and without fault;

[0091] 504, the water temperature exceeds the second or third preset water temperature, disconnect the second switch (either the controller actively disconnects or the third switch is passively triggered);

[0092] 505. From the execution of the first operation of disconnecting the first switch, if the first preset time period has elapsed until the second switch is disconnected, determine whether the change in the electrical parameter detected by the electrical parameter detector exceeds the preset value. If it does, execute 506; otherwise, proceed to 507.

[0093] 506, Generate fault prediction signal;

[0094] 507, the first switch is confirmed to be stuck.

[0095] The implementation methods for 401-406 and 501-507 have been described above and will not be repeated here.

[0096] In the above examples, with Figure 1 This example illustrates how to perform fault prediction. (For example...) Figure 3 In the scenario described below, only the differences are explained. When N is greater than 1, when the thermostat detects that the water temperature has reached the first preset water temperature, the first operation of disconnecting the first switch corresponding to each heating unit is performed. Each first switch has a corresponding first relay. The specific implementation method of performing the first operation is as described above. When each first switch is not faulty, after each first switch is disconnected, compared with the closed state of each first switch, it can be regarded as the load in the circuit increases, which leads to a decrease in the main circuit current value. Therefore, after stopping the power supply to each first switch, if the change in electrical parameters detected by the electrical parameter detector exceeds the preset value, it indicates that each first switch is disconnected. The preset value (first preset value) can be less than or equal to the difference between the main circuit current value when each first switch is closed and the main circuit current value when each first switch is disconnected.

[0097] In some embodiments, for scenarios where N is greater than 1, the time elapsed from the execution of the first operation to when the change in electrical parameters detected by the electrical parameter detector exceeds a preset value is obtained. When the time elapsed is not less than a first preset time elapsed, a fault prediction signal is generated. At this time, it can only indicate that at least one of the N first switches may fail, but it is impossible to determine which first switch may fail. Therefore, the method further includes: sequentially executing the first operation of disconnecting each first switch, and using the methods described in 202 to 203 above to perform fault prediction for each first switch. Repeated parts will not be described again. For example, for four heating units, each corresponding to a first switch KM1 to KM4, when the water temperature reaches a first preset water temperature, the controller controls the first relay of each of the first switches KM1 to KM4 to disconnect, performing a first operation to disconnect all the first switches KM1 to KM4, determining whether the change in the electrical parameters detected by the electrical parameter detector exceeds a preset value (first preset value), if it exceeds, obtaining the time elapsed from the execution of the first operation to the time when the change in the electrical parameters detected by the electrical parameter detector exceeds the preset value (first preset value), and generating a fault prediction signal when the time is not less than the first preset time.At this point, it can only be determined that one of the first switches from KM1 to KM4 may malfunction. To determine which of these first switches is likely to malfunction, the controller disconnects the first relay corresponding to switch KM1 and turns on the first relays of switches KM2 to KM4. It then determines whether the change in electrical parameters detected by the electrical parameter detector exceeds a preset value (a third preset value, corresponding to each first switch, less than or equal to the difference between the current detected when KM1 is closed (all other switches are closed) and the current detected when KM1 is open (all other switches are closed). If the change exceeds this value, the controller obtains the time elapsed from the time the first relay corresponding to switch KM1 is disconnected until the change in electrical parameters detected by the electrical parameter detector exceeds the preset value (third preset value). If this time elapsed is not less than the first preset time elapsed, a fault prediction signal is generated, indicating that switch KM1 may malfunction. If this time elapsed is less than the first preset time elapsed, a fault prediction signal is generated. During the specified time period, the controller controls the first relay corresponding to the first switch KM2 to open, and controls the first relays of the first switches KM1, KM3 to KM4 to turn on. It determines whether the change in the electrical parameter detected by the electrical parameter detector exceeds a preset value (a third preset value, corresponding to each first switch, less than or equal to the difference between the current detected when KM2 is closed (all other switches are closed) and the current detected when KM2 is open (all other switches are closed). If it exceeds the preset value, the controller obtains the time elapsed from the time the first relay corresponding to the first switch KM2 is opened to the time when the change in the electrical parameter detected by the electrical parameter detector exceeds the preset value (third preset value). If the time is not less than the first preset time, a fault prediction signal is generated, indicating that the first switch KM2 may be faulty. If the time is less than the first preset time, the controller controls the first relay corresponding to the first switch KM3 to open, and so on, performing fault prediction for each first switch separately.

[0098] Figure 6 This is a schematic diagram of the fault prediction method according to an embodiment of this application, such as... Figure 6 As shown, for Figure 3 In the scenario described, the method includes:

[0099] 601, when the thermostat detects that the water temperature exceeds the first preset water temperature, execute the first operation of disconnecting all N first switches;

[0100] 602. Within the first preset time period starting from the first operation of disconnecting all N first switches, determine whether the change of electrical parameters detected by the electrical parameter detector exceeds the first preset value. If it exceeds the preset value, proceed to 603; otherwise, proceed to 604.

[0101] 603, confirm that N first switches are normal and without faults;

[0102] 604. After the first operation of disconnecting N first switches is executed, if the first preset time exceeds the first preset time, but within the second preset time, it is determined whether the change of electrical parameters detected by the electrical parameter detector exceeds the first preset value. If it does, execute 605; otherwise, set P=1 and proceed to 606.

[0103] 605, Generate fault prediction signal; Set P = 1;

[0104] 606. Determine if P is less than or equal to N. If the result is yes, proceed to 607; otherwise, end.

[0105] 607, The controller controls the first switch KMP to be disconnected, but controls the other first switches to be turned on (by controlling the first relays corresponding to each first switch);

[0106] 608. Within a first preset time period starting from the first operation of disconnecting the first switch KMP, determine whether the change in the electrical parameter detected by the electrical parameter detector exceeds a second preset value. If it does, proceed to 609; otherwise, proceed to 610.

[0107] 609. Confirm that the first switch KMP is normal and without fault;

[0108] 610. After the first operation of disconnecting the first switch KMP is executed, if the first preset time period has exceeded, but within the second preset time period, it is determined whether the change of the electrical parameter detected by the electrical parameter detector exceeds the second preset value. If it exceeds, execute 611; otherwise, proceed to 612.

[0109] 611, generate the fault prediction signal for the first switch KMP; P+1, and return to 606;

[0110] 612, confirm that the first switch KMP is stuck; P = P + 1, and return to 606.

[0111] In some embodiments, the second switch can be disconnected after the above method is completed. Alternatively, in 610, the second switch is disconnected (either actively disconnected by the controller or passively triggered by the third switch) when the water temperature exceeds the second preset water temperature or the third preset water temperature. The second preset duration is equal to the duration required from the execution of the first operation to the disconnection of the second switch. This embodiment of the application is not intended to limit the scope of the invention.

[0112] It is worth noting that the above appendix Figure 2 and Figures 4 to 6 The embodiments described herein are merely illustrative and are not limited thereto. For example, the execution order of various operations can be appropriately adjusted, and additional operations can be added or some operations can be removed. Those skilled in the art can make appropriate modifications based on the above description, and are not limited to the above-described embodiments. Figure 2 and Figures 4 to 6 The records.

[0113] The above explanation uses current as the electrical parameter as an example. The implementation method is similar when the electrical parameter is voltage, and will not be illustrated here.

[0114] As can be seen from the above embodiments, the time elapsed from the execution of the first operation to the time when the change in electrical parameters detected by the electrical parameter detector exceeds a preset value is obtained. When the time elapsed is not less than the first preset time elapsed, a fault prediction signal is generated. Thus, the possibility of switch failure can be predicted in advance, so that maintenance personnel can maintain or repair the switch in time before the switch actually fails, thereby extending the service life of the heating system.

[0115] In addition, a second switch connected in series with the first switch is installed in the circuit. By using a dual-switch system to control the start and stop of the heating element, the second switch can be disconnected to protect the circuit if the first switch is about to fail or has already failed. This protects the circuit from overheating and damage to the heating element.

[0116] In addition, by designing a second preset duration related to the time when the second switch is disconnected, it is possible to accurately predict whether the automatic disconnection of the first switch is abnormal.

[0117] Second aspect of the embodiments

[0118] An embodiment of the second aspect of this application provides an apparatus, Figure 7 This is a schematic diagram of the heating system fault prediction device according to an embodiment of this application. Figure 7 This is a schematic diagram of a fault prediction device according to an embodiment of this application, such as... Figure 7 As shown, the fault prediction device 700 of this application embodiment may include: at least one interface ( Figure 7 (Not shown in the image), controller 701, memory 702; memory 702 is coupled to controller 701. Memory 702 can store various data; it also stores program 703 for fault determination, and executes program 703 under the control of controller 701, and stores various preset thresholds and predetermined conditions, etc.

[0119] In some embodiments, the controller 701 can implement the fault prediction method described in the first aspect embodiment. For example, the controller 701 can be configured to: perform a first operation of disconnecting the first switch when a predetermined condition is met; acquire the time elapsed from the execution of the first operation to when the change in the electrical parameter detected by the electrical parameter detector exceeds a preset value; and generate a fault prediction signal when the time elapsed is not less than a first preset time elapsed. For a detailed description of the specific implementation of the controller 701, please refer to the foregoing embodiments; further details will not be provided here.

[0120] It is worth noting that the fault prediction device 700 may also include a communication module 704, or it may not necessarily include one. Figure 7 All components shown; in addition, the fault prediction device 700 may also include Figure 7 For components not shown in the diagram, please refer to relevant technologies. They will not be listed here. For example, the fault prediction device 700 may also include an electrical parameter detector, and the controller 701 is connected to the electrical parameter detector.

[0121] In this embodiment, the controller 701, sometimes also referred to as a processor or operation control, may include a microcontroller or other processor device and / or logic device. The controller 701 receives input and controls the operation of various components of the fault prediction device 700.

[0122] In this embodiment, the memory 702 may be one or more of a cache, flash memory, hard drive, removable medium, volatile memory, non-volatile memory, or other suitable means. It can store various types of information, and also programs for executing that information. The controller 701 can execute the program stored in the memory 702 to perform information storage or processing, etc. The functions of other components are similar to those in existing systems and will not be described further here. The components of the fault prediction device 700 can be implemented using dedicated hardware, firmware, software, or a combination thereof, without departing from the scope of this application.

[0123] For example, when the heating system is applied to an electric water heater, the controller 701 can be configured separately from the controller of the electric water heater (heating system). For example, the controller 701 can be configured as a chip connected to the controller of the electric water heater (heating system), and the two can control each other. Alternatively, the function of the controller 701 can be integrated into the controller of the electric water heater (heating system) itself. This application embodiment is not intended to limit the scope of the invention.

[0124] Third aspect of the embodiments

[0125] An embodiment of the third aspect of this application provides an electric water heater. This electric water heater may be a commercial electric water heater, but this embodiment is not intended to limit it. Figure 8 This is a schematic diagram of an electric water heater according to an embodiment of this application. Figure 8 As shown, the electric water heater 800 includes:

[0126] A heating system 801 includes an electrical parameter detector and at least one heating unit. The heating unit includes a heating element and a first switch for controlling the start and stop of the heating element. The electrical parameter detector is used to detect the electrical parameters of the power supply line of the heating element.

[0127] Heating system fault prediction device 802;

[0128] Inner liner 803, the heating element is used to heat the water in the inner liner.

[0129] In some embodiments, the operating current of the heating system 801 can be a single-phase power supply current or a three-phase power supply current, and its specific configuration can be referred to the first aspect. Figure 1 and Figure 3 The implementation of the heating system fault prediction device 802 can be referred to the fault prediction device 700 in the third aspect, and will not be repeated here.

[0130] In some embodiments, the fault prediction device 802 can be configured separately from the controller of the electric water heater (heating system). For example, the fault prediction device 802 can be configured as a chip connected to the controller of the electric water heater (heating system), and the two can control each other. Alternatively, the function of the fault prediction device 802 can be integrated into the controller of the electric water heater (heating system) itself. This application embodiment is not intended to limit the scope of the invention.

[0131] In some embodiments, the fault prediction device is configured to perform the fault prediction method in the first aspect embodiment, and specific details can be found in the first aspect embodiment, where repeated details will not be repeated.

[0132] It is worth noting that the electric water heater 800 may also include Figure 8 For components not shown in the document, please refer to relevant technologies; they will not be listed here.

[0133] The structure of the heating system 801 will be further described below, and the parts that are repeated in the first aspect of the embodiment will not be repeated. Figure 9 This is a schematic diagram of the heating system configuration according to an embodiment of this application, as shown below. Figure 9 As shown, the heating system includes an electrical parameter detector 901 and at least one heating unit 902. Each heating unit includes heating elements 9021 (EH1 to EH5) and a first switch 9022 (KM1 to KM5) for controlling the start and stop of the heating elements. The electrical parameter detector 901 is used to detect the electrical parameters of the power supply line to the heating elements; for example, the electrical parameter detector 901 includes a current transformer for detecting the current in the power supply main line of the heating elements. The electrical parameter detector 901 can be installed on the power supply main line.

[0134] In some embodiments, the heating system 801 further includes: a controller 903 and a first relay 904 connected to the controller 903. The first relay 904 is also connected to a first switch 9022. The first relay 904 and the first switch 9022 correspond one-to-one and are used to control the on / off state of the first switch 9022. The controller 903 and the first switch 9022 (one or more) form a first circuit, and the first relay is disposed on the first circuit.

[0135] In some embodiments, the heating system 801 further includes a thermostat 905 electrically connected to the controller for detecting the water temperature after heating. That is, a thermostat electrically connected to the controller is provided on the aforementioned first circuit. When the thermostat detects that the water temperature has reached a first preset water temperature, the controller 903 performs a first operation of disconnecting the first switch. The specific control method can be referred to the embodiment of the first aspect.

[0136] In some embodiments, the heating system 801 further includes: a second switch 906 disposed on the power supply line of the heating unit and connected in series with the first switch; the controller 903 and the second switch 906 form a second circuit. Wherein, when the heating system includes N heating units, it also includes N first switches (corresponding to N first relays) and N second switches corresponding one-to-one with the N first switches, each second switch being connected in series with a corresponding first switch.

[0137] In some embodiments, the heating system 801 further includes: a second relay 907 connected to the controller 903 for controlling the on / off state of the second switch 906. The second relay 907 is disposed in the second circuit and is also connected to the second switch 906. The second relay 907 and the second switch 906 correspond one-to-one (i.e., including N second relays 907, and the N second relays 907 are synchronously controlled by the controller to be turned on or off), or the second relay 907 is used to control the on / off state of all second switches 906 (i.e., including 1 second relay).

[0138] In some embodiments, after the controller performs the first operation, when the thermostat detects that the water temperature exceeds the second preset water temperature, the controller performs a second operation of disconnecting the second switch, as can be seen in the embodiments of the first aspect.

[0139] In some embodiments, the first switch and / or the second switch includes an AC contactor.

[0140] In some embodiments, the heating system 801 further includes a third switch 908 for controlling the opening and closing of the second switch. The third switch switches between an on state and an off state according to temperature changes. That is, a third switch 908 is also provided on the second circuit. This third switch can be a high-temperature limit switch; when the water temperature after being heated by the heating system exceeds a third preset water temperature, the third switch switches from an on state to an off state. For specific implementation details, please refer to the embodiments of the first aspect.

[0141] It is worth noting that the heating system 801 may also include Figure 9 For components not shown in the document, please refer to relevant technologies; they will not be listed here.

[0142] This application also provides a computer program, wherein when the program is executed in a fault prediction device or an electric water heater, the program causes the main controller to perform the fault prediction method described in the first aspect embodiment.

[0143] This application also provides a storage medium storing a computer program, wherein the computer program causes a fault prediction device or an electric water heater to perform the fault prediction method described in the first aspect of the embodiment.

[0144] The data transmission apparatus described in conjunction with the embodiments of this application can be directly embodied in hardware, software modules executed by a processor, or a combination of both. For example, one or more and / or combinations of one or more functional block diagrams shown in the figures can correspond to either software modules in a computer program flow or hardware modules. These software modules can respectively correspond to... Figure 1 The steps are shown. These hardware modules can be implemented by embedding these software modules, for example, using a field-programmable gate array (FPGA).

[0145] The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. A storage medium can be coupled to the processor, enabling the processor to read information from and write information to the storage medium; or the storage medium can be an integral part of the processor. The processor and storage medium can reside in an ASIC. The software module can be stored in the memory of the information processing system or in a memory card that can be inserted into the information processing system.

[0146] One or more of the functional block diagrams and / or combinations thereof described in the figures can be implemented as a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof for performing the functions described in this application. One or more of the functional block diagrams and / or combinations thereof described in the figures can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0147] The present application has been described above with reference to specific embodiments. However, those skilled in the art should understand that these descriptions are exemplary and not intended to limit the scope of protection of the present application. Those skilled in the art can make various modifications and variations to the present application based on its spirit and principles, and these modifications and variations are also within the scope of the present application.

Claims

1. A method for predicting faults in a heating system, the heating system comprising an electrical parameter detector and at least one heating unit, the heating unit comprising a heating element and a first switch for controlling the start and stop of the heating element, the electrical parameter detector being used to detect the electrical parameters of the power supply line of the heating element, characterized in that, The method includes: When predetermined conditions are met, the first operation of disconnecting the first switch is performed; The time elapsed from the execution of the first operation to the point when the change in electrical parameters detected by the electrical parameter detector exceeds a preset value is obtained. When the time elapsed is not less than a first preset time elapsed, a fault prediction signal is generated. The first switch includes an AC contactor, and the first preset time elapsed is the time required for the first switch to go from the state where the contact coil is engaged to the state where the contact coil cannot be engaged when the first switch is not faulty.

2. The method according to claim 1, characterized in that, The heating system also includes a thermostat for detecting the temperature of the heated water, which satisfies the predetermined condition when the water temperature reaches the first preset water temperature.

3. The method according to claim 1, characterized in that, The electrical parameter detector includes a current transformer for detecting the current in the power supply trunk of the heating element.

4. The method according to any one of claims 1 to 3, characterized in that, When the duration is not less than a first preset duration, generating a fault prediction signal includes: When the duration is not less than a first preset duration and not greater than a second preset duration, the first switch is determined to be abnormally disconnected and the fault prediction signal is generated, wherein the second preset duration is greater than the first preset duration.

5. The method according to claim 4, characterized in that, The fault prediction signal includes fault warning signal and / or system maintenance signal.

6. The method according to any one of claims 1 to 3, characterized in that, The method further includes: If the electrical parameter detector does not detect a change in electrical parameters exceeding a preset value within a second preset duration, it is determined that the first switch has stuck and a fault signal is generated, wherein the second preset duration is longer than the first preset duration.

7. The method according to claim 4, characterized in that, The heating system also includes a second switch disposed on the power supply line of the heating unit and connected in series with the first switch; The second preset duration is a predetermined value or the second preset duration is not greater than the time required from the execution of the first operation to the opening of the second switch.

8. The method according to claim 6, characterized in that, The heating system also includes a second switch connected in series with the first switch; The second preset duration is a predetermined value or the second preset duration is not greater than the time required from the execution of the first operation to the opening of the second switch.

9. The method according to claim 7 or 8, characterized in that, After performing the first operation, if it is detected that the water temperature heated by the heating system exceeds the second preset water temperature, the second switch is turned off, and the second preset water temperature is greater than the first preset water temperature.

10. The method according to claim 7 or 8, characterized in that, The heating system also includes a third switch for controlling the opening and closing of the second switch. When the water temperature after being heated by the heating system exceeds a third preset water temperature, the third switch switches from the on state to the off state.

11. The method according to claim 8, characterized in that, When it is determined that the first switch is stuck, the method further includes: disconnecting the second switch.

12. The method according to claim 7 or 8, characterized in that, The second switch includes an AC contactor.

13. A heating system fault prediction device, comprising a controller configured to perform the heating system fault prediction method according to any one of claims 1 to 12.

14. An electric water heater, characterized in that, The electric water heater includes: A heating system includes an electrical parameter detector and at least one heating unit, the heating unit including a heating element and a first switch for controlling the start and stop of the heating element, the electrical parameter detector being used to detect the electrical parameters of the power supply line of the heating element; The heating system fault prediction device according to claim 13; The inner liner, wherein the heating element is used to heat the water in the inner liner.

15. The electric water heater according to claim 14, characterized in that, The electrical parameter detector includes a current transformer for detecting the current in the power supply trunk of the heating element.

16. The electric water heater according to claim 14, characterized in that, The heating system further includes a thermostat electrically connected to the controller for detecting the water temperature after heating. When the thermostat detects that the water temperature has reached a first preset water temperature, the controller performs a first operation of disconnecting the first switch.

17. The electric water heater according to claim 16, characterized in that, The heating system further includes: a second switch disposed on the power supply line of the heating unit and connected in series with the first switch; After the controller performs the first operation, when the thermostat detects that the water temperature exceeds the second preset water temperature, the controller performs the second operation of disconnecting the second switch.

18. The electric water heater according to claim 17, characterized in that, The second switch includes an AC contactor.

19. The electric water heater according to claim 17, characterized in that, The heating system also includes a third switch for controlling the opening and closing of the second switch, the third switch switching between an on state and an off state according to temperature changes.

20. The electric water heater according to claim 19, characterized in that, The third switch is a high-temperature limit switch. When the water temperature after being heated by the heating system exceeds a third preset water temperature, the third switch switches from the on state to the off state.

Images