US20240200831A1

US20240200831A1 - Method and apparatus for determining fault of heating apparatus, and electric water heater

Info

Publication number: US20240200831A1
Application number: US18/576,292
Authority: US
Inventors: Xing Liu; Ran Tao; Qiang Huang
Original assignee: AO Smith China Water Heater Co Ltd
Current assignee: AO Smith China Water Heater Co Ltd
Priority date: 2021-06-16
Filing date: 2022-03-15
Publication date: 2024-06-20
Also published as: CA3225273A1; WO2022262334A1; CN115479395A

Abstract

Embodiments of this disclosure provide a method and apparatus for determining a fault of a heating device and an electric water heater. When the heating device includes at least two heating units in an operating state parallelly arranged on branches of a same phase line and the heating unit include a heating element and a switch controlling the heating element, the method includes: acquiring a main circuit current value of the phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit when the main circuit current value is not greater than a first current value; and acquiring a variation value of the main circuit current value caused by turning on/off the switch, and determining that a fault occurs in a heating element controlled by the switch when the variation value of the main circuit current value is not greater than a preset variation value. With the embodiments of this disclosure, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Application No. 202110665170.1 filed on Jun. 16, 2021, the entire content thereof is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to the field of diagnosis of faults of devices, and in particular to a method and apparatus for determining a fault of a heating device and an electric water heater.

BACKGROUND

Commercial high-power electric water heaters are generally used in high-flow bathing scenarios such as hotels, guesthouses, shower centers, hospitals, and homes. There are a large number of heating elements in commercial high-power electric water heaters, and if faults occur in the heating elements, user experiences of water will be affected.
It should be noted that the above description of the background art is merely provided for clear and complete explanation of this disclosure and for easy understanding by those skilled in the art. And it should not be understood that the above technical solution is known to those skilled in the art as it is described in the background art of this disclosure.

SUMMARY OF THE DISCLOSURE

In related techniques, a separate current monitoring device in series with each heating element may be provided for each heating element to find a heating element where a fault occurs by detecting a branch current value passing through each heating element. Therefore, for fault detection scenarios of a plurality of heating elements, detection costs are relatively high.
Addressed to at least one of the above problems, embodiments of this disclosure provide a method and apparatus for determining a fault of a heating device and an electric water heater, in which whether a fault occurs in a heating element may be determined according to a main circuit current value, and the heating element where the fault occurs may be determined according to a variation value of the main circuit current. Therefore, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability.
Specific technical solutions of the embodiments of this disclosure are as follows.
According to a first aspect of the embodiments of this disclosure, there is provided a method for determining a fault of a heating device, in which when the heating device includes at least two heating units in an operating state parallelly arranged on branches of a same phase line and the heating unit includes a heating element and a switch controlling the heating elements, the method includes:

- acquiring a main circuit current value of the phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit when the main circuit current value is not greater than a first current value; and
- acquiring a variation value of the main circuit current value caused by turning on/off the switch, and determining that a fault occurs in a heating element controlled by the switch when the variation value of the main circuit current value is not greater than a preset variation value.

According to a second aspect of the embodiments of this disclosure, there is provided a method for determining a fault of a heating device, in which when an operating current of the heating device is a three phase supply current, each phase line of three phase lines includes at least two heating units in an operating state parallelly arranged on branches and the heating unit include a heating element and a switch controlling the heating element, the method includes:

- acquiring a main circuit current value of each phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit in a phase line where the main circuit is located when the main circuit current value is not greater than a first current value; and
- acquiring a variation value of the main circuit current value caused by turning on/off a switch of the phase line where the fault of the heating element occurs, and determining that a fault occurs in a branch where a heating element controlled by the switch is located when the variation value of the main circuit current value is not greater than a preset variation value.

According to a third aspect of the embodiments of this disclosure, there is provided an apparatus for determining a fault of a heating device, including a processor, the processor being configured to execute the method for determining a fault of a heating device as described in the first or second aspect.
According to a fourth aspect of the embodiments of this disclosure, there is provided an electric water heater, including:

- a heating device including at least two heating units parallelly arranged on branches of a same phase line, the heating unit including a heating element and a switch controlling operation of the heating element; the apparatus for determining a fault of a heating device as described in the third aspect; and a waterway assembly, the heating elements being used to heat water in the waterway assembly.

An advantage of the embodiments of this disclosure exists in that whether a fault occurs in a heating element may be determined according to the main circuit current value, and the heating element where the fault occurs may be determined according to the variation value of the main circuit current. Therefore, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability.
With reference to the following description and drawings, the particular embodiments of this disclosure are disclosed in detail, and the principle of this disclosure and the manners of use are indicated. It should be understood that the scope of the embodiments of this disclosure is not limited thereto. The embodiments of this disclosure contain many alternations, modifications and equivalents within the spirits and scope of the terms of the appended claims. Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings described herein are for explanation only, and are not intended to limit the scope of this disclosure in any way. In addition, shapes and proportional dimensions of the components in the drawings are illustrative only and are intended to assist in understanding this disclosure, but are not intended to specifically limit the shapes and proportional dimensions of the components in this disclosure. With the teachings of this disclosure, those skilled in the art may choose various possible shapes and proportional sizes according to specific circumstances to implement this disclosure.

FIG. 1 is a schematic diagram of the method for determining a fault of an embodiment of this disclosure;

FIGS. 2-4 are schematic diagrams of a heating circuit in the embodiment of this disclosure;

FIG. 5 is a schematic diagram of an implementation of operation 102 in the embodiment of this disclosure;

FIG. 6 is a schematic diagram of the method for determining a fault of an embodiment of this disclosure;

FIGS. 7 and 8 are schematic diagrams of connection relationships between the heating units in the embodiment of this disclosure;

FIG. 9 is a schematic diagram of the method for determining a fault of an embodiment of this disclosure;

FIG. 10 is a schematic diagram of a structure of the apparatus for determining a fault of an embodiment of this disclosure;

FIG. 11 is a schematic diagram of a structure of the electric water heater in the embodiment of this disclosure; and

FIG. 12 is a schematic diagram of a structure of the electric water heater in the embodiment of this disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

The technical solutions of this disclosure shall be explained below in detail with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate this disclosure and not to limit the scope of this disclosure. After reading this disclosure, all modifications to various equivalent forms of this disclosure by those skilled in the art will fall within the scope of the claims attached to this disclosure.
In the embodiments of this disclosure, terms “first”, and “second”, etc., are used to differentiate different elements with respect to names, and do not indicate spatial arrangement or temporal orders of these elements, and these elements should not be limited by these terms. Terms “and/or” include any one and all combinations of one or more relevantly listed terms. Terms “contain”, “include” and “have” refer to existence of stated features, elements, components, or assemblies, but do not exclude existence or addition of one or more other features, elements, components, or assemblies.
All technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this disclosure pertains, unless otherwise defined. The terminology used in the description of this disclosure is for the purpose of describing particular embodiments and is not intended to limit this disclosure. The term “and/or” as used herein includes any and all combinations of one or more of the associated listed items.

Embodiment of the First Aspect

The embodiment of the first aspect of this disclosure provides a method for determining a fault of a heating device, wherein when the heating device includes at least two heating units in an operating state parallelly arranged on branches of a same phase line and the heating unit includes a heating element and a switch controlling the heating element, as shown in FIG. 1 , which is a schematic diagram of the method for determining a fault, the method includes:

- 101: acquiring a main circuit current value of the phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit when the main circuit current value is not greater than a first current value; and
- 102: acquiring a variation value of the main circuit current value caused by turning on/off the switch, and determining that a fault occurs in a heating element controlled by the switch when the variation value of the main circuit current value is not greater than a preset variation value.

In some embodiments, the heating device includes at least two (hereinafter referred to as M) heating units in an operating state parallelly arranged on branches of a same phase line; where, M is an integer not less than 2. The M heating units are parallelly arranged on branches of the same phase line, and by supplying operating currents to the heating units, the heating units are warmed up and caused to generate heat, thereby achieving a function of heating. The operating current of the heating device may be a single-phase power supply current, or a two-phase power supply current, or a three phase power supply current, etc., and the embodiment of this disclosure is not limited thereto. For example, when the operating current is a single-phase power supply current, the heating device only includes one phase line. FIG. 2 is a schematic diagram of a heating circuit, as shown in FIG. 2 , that is, the M heating units are parallelly arranged on M branches of the one phase line, and when the operating current is a three phase power supply current, the heating device includes three phase lines. FIG. 3 is another schematic diagram of the heating circuit. As shown in FIG. 3 , the three phase lines are U phase, V phase, and W phase, meaning that on each of the three phase lines, there are M heating elements parallelly arranged on M branches (M=4), which shall not be enumerated herein any further.
Furthermore, in operation, the heating device may include not only M heating units in an operating state parallelly arranged on the branches of a same phase line, but also P heating units in a stopped operating state (P is an integer greater than or equal to 0). The P heating units and the M heating units are parallelly arranged on the branches of the same phase line. FIG. 4 is another schematic diagram of the heating circuit. As shown in FIG. 4 , a part in dotted lines in FIG. 4 refers to the heating unit in the stopped operating state, and a part in solid lines refers to the heating unit in the operating state; where, M=4, and P=1. On each of the three phase lines, there are M+P heating units parallelly arranged on M+P branches.
It should be noted that in the above example, each branch includes a heating unit. However, the embodiment of this disclosure is not limited thereto, and each branch may include at least two heating elements connected in series, which shall not be repeated herein any further.
In some embodiments, each heating unit includes heating element(s) and a switch controlling the heating element(s). For example, the heating element may be a heating rod, and the switch may be a relay or a contactor.
In some embodiments, the at least two (i.e. M) heating units are in the operating state, wherein being in the operating state refers to that the switch controlling the heating element in the heating unit is in an on state, and being in a stopped operating state refers to that the switch controlling the heating element in the heating unit is in an off state.
In some embodiments, in 101, the main circuit current value of the phase line is acquired when the operating state of the heating units is not changed. The operating state of the heating units being not changed refers to that the on/off states of the switches are not changed (i.e. remaining in the on state) and the operating power of the heating elements is not changed. Furthermore, if the heating device also includes the P heating units in a stopped operating state parallelly arranged on the branches of the same phase line, the operating state of the heating units in the stopped operating state needs also to be remained unchanged, that is, the turning on/off states of the switches are unchanged (i.e. remaining in the off state). A current sensor or a current transformer may be used to acquire the main circuit current value of the phase line. For example, the current sensor or current transformer may be arranged on a main circuit of the phase line to acquire the main circuit current value, and reference may be made to existing techniques for details, which shall not be repeated herein any further.
How to perform fault diagnosis shall be described below by taking a main circuit current value of a phase line as an example. If the heating device includes a plurality of phase lines, implementations of performing fault diagnosis according to main circuit current values of the phase lines are similar, and reference may be made to the embodiment of the second aspect for details, which shall not be repeated herein any further.
In some embodiments, before diagnosis, it is optional to correct and compensate for the acquired main circuit current value to improve a reliability of the fault diagnosis. When faults occur in the heating elements, in comparison to a case where no fault occurs in the heating elements, it may be deemed that a load in the circuit is increased, which leads to a decrease in the main circuit current value (for example, a fault occurs in a heating element, the branch where the heating element is located is in an open state, which leads to an increase of a load resistance in the circuit and causes a decrease in the main circuit current value). Hence, when the main circuit current value is not greater than the first current value, it is determined that a fault occurs in the heating element in at least one heating unit. It should be noted that after compensating for and correcting the acquired main circuit current value, the compensated and corrected main circuit current value may be compared with the first current value, so as to determine whether a fault occurs in the heating element.
For example, the first current value may be a preset current value, or may be a main circuit current value previously-detected when no fault occurs in the heating elements, which shall be described below by way of examples.
In some embodiments, the first current value is a preset current value, the preset current value being set based on a total current A1 of all N heating elements in operation on the same phase line, or being set based on a total current A2 of N−1 heating elements in the N heating elements; where, N is an integer not less than 2. For example, the first current value may be set to be a value in a range of [A2, A1); however, the embodiment of this disclosure is not limited thereto. Wherein, the total current A1 or A2 refers to a theoretical total current value in N or N−1 heating elements when no fault occurs and are all in an operation state; where, N is equal to M.
In some embodiments, the first current value may be the main circuit current value previously-detected when no fault occurs in the heating elements, and the first current value denotes a total current of all the heating elements in an operation state on the same phase line (when no fault occurs therein); and the method may further include: updating the acquired main circuit current value to the first current value when it is determined that no heating unit occurs a fault. For example, when it is determined that no heating unit occurs a fault, the first current value may be updated every predetermined time interval. As the loads of the heating elements will change with change of usage time. Hence, periodically updating the first current value may further improve the reliability of the fault diagnosis.
It can be seen from the above embodiment that whether any heating element occurs a fault may be determined by comparing the main circuit current value with the first current value, and when it is determined that there exist heating element that occurs a fault, which heating element occurs a fault may be determined according to the variation value of the main circuit current value.
In some embodiments, in 102, the variation value of the main circuit current value caused by turning on/off the switch may be acquired. For example, a heating element in operation is sequentially selected, and in a case where operating states of other heating elements are not changed (the on/off states of the switch are not changed and operating power of a heating element corresponding to a switch in an on state is not changed), a first main circuit current value when the heating element is in operation and a second main circuit current value after the heating element stops operating are detected, and the variation value of the main circuit current value is determined according to the first main circuit current value and the second main circuit current value. For example, after the switch controlling the operation of the heating element is turned on, the first main circuit current value is detected, and after the switch controlling the operation of the heating element is turned off, the second main circuit current value is detected.
In some embodiments, when the variation value of the main circuit current value is not greater than the preset variation value, it is determined that a fault occurs in the heating element controlled by the switch. The preset variation value is set based on a branch current A3 of the heating element, for example, the preset variation value may be a value within a range of [0, A3). For example, when the preset variation value is 0, the variation value of the main circuit current value is 0, that is, the main circuit current value is not changed before and after the switch is turned on and off, indicating that a fault occurs in the heating element controlled by the switch.
FIG. 5 is a schematic diagram of an implementation of operation 102. As shown in FIG. 5 , operation 102 includes:

- 501: acquiring a current first main circuit value of the phase line;
- 502: selecting an i-th heating element in M heating elements in an operation state, wherein in initial operation, i=1, i being an integer greater than or equal to 1 and less than or equal to M;
- 503: turning off the switch controlling the i-th heating element;
- 504: acquiring a current second main circuit value of the phase line;
- 505: determining whether variation value of the first main circuit current value and the second main circuit current value are not greater than the preset variation value, and executing 506 when a result of determination is yes, otherwise, executing 507;
- 506: determining a fault occurs in the i-th heating element; and
- 507: turning on the switch controlling the i-th heating element, making i=i+1, and turning back to 501.

In some embodiments, after determining the heating element where a fault occurs, the method may further include (not shown in figures): controlling the heating element where the fault occurs to stop operating; and starting a heating element where no fault occurs that is not in operation and is on the same phase line as the heating element where the fault occurs. For example, the heating element where the fault occurs may be controlled to stop operating by turning off the switch, and furthermore, fault information may be reported to a backend server. When the heating device includes at least two phase lines, if a fault is detected in a heating element of a branch on a phase line, heating elements of other phase lines in the branch may be controlled (for the convenience of explanation, heating elements of different phase lines in the box shown in FIG. 3 are hereinafter referred to as a group of heating elements) to stop operating, so as to avoid multiphase unbalanced operation. In addition, in order to ensure heating power, heating elements not in operation where no fault occurs and are on the same phase line as the heating element where the fault occurs may also be started, so as to replace heating elements where faults occur on the same phase line (or, when the group of heating elements stop operating, heating elements on different phase lines in the same group as the replaced heating elements are simultaneously started, i.e. a group of heating elements are started to replace a group of heating elements stopping operating). As shown in FIG. 4 , when faults occur in a second group of U-phase heating elements, stop operating of all the heating elements on U-phase, V-phase and W-phase of the second group, and start a fifth group of heating elements shown by dotted lines (start all the heating elements on U phase, V phase and W phase heating elements).
In some embodiments, the method may further include (not shown in figures):

- determining that a fault occurs in a switch in at least one heating unit when the main circuit current value is not less than a second current value.

In some embodiments, a method for determining the second current value is similar to that for determining the first current value, and shall not be repeated herein any further. The second current value is greater than or equal to the first current value, and when the main circuit current value is not less than the second current value, it is determined that a fault occurs in a switch in at least one heating unit. The fault in the switch may be relay adhesion or contactor adhesion, etc., which shall not be enumerated herein any further.
In some embodiments, after determining that a fault occurs in a switch in at least one heating unit, the power switch of the heating device is disconnected, and optionally, fault information may be reported to the backend server.
In some embodiments, when heating lengths (operating time lengths) of the heating elements are not evenly distributed, it is prone to lead to differences between service lives of the heating elements. To avoid increase of failure rates of the heating elements, the method may further include (not shown in figures): calculating a cumulative operating time of the at least two heating units parallelly arranged on the branches of the same phase line according to the main circuit current value; and adjusting starting sequences of the heating elements according to the cumulative operating time.
For example, when the main circuit current value is not no greater than the first current value and is not no less than the second current value, it indicates that no fault occurs in the heating elements and switches in the current heating device, that is, the M heating elements parallelly arranged on the same phase line have been in operating state. The operating times of the heating elements are real time counted, and if a heating element where a fault exists is found, stop operating of the heating element. For this heating element, an operating time until a detection time is taken as the cumulative operating time. At the same time, heating elements where no fault occurs that are not in operation and in the same phase line as the heating element where the fault occurs are started, and cumulative operating times of the replaced heating elements are accumulated from the detection time. In addition, for other heating elements where no fault occurs and have been in an operating state, their operating times are cumulatively calculated. When the heating device includes at least two phase lines, cumulative operating times of the entire group of heating elements may be calculated in units of the above group of heating elements, and a specific calculation method shall not be repeated herein any further.
In some embodiments, starting priorities of each (or each groups of) heating element(s) are dynamically adjusted according to the length of cumulative operating time; wherein starting priority of heating element (group) with long cumulative operating time is low, and starting priority of heating element(group) with short cumulative operating time is high, and (groups of) heating elements are started according to the starting priorities. This may ensure balanced lives of a plurality of heating elements, so as to extend their usage lives and reduce failure rates.
For example, as shown in FIG. 4 , from a starting time T1, a first to fourth groups of heating elements are in an operating state. When a fault is detected in U-phase heating element (T2 moment) of a second group, stop operating of all the heating elements on U-phase, V-phase and W-phase of the second group, and start a fifth group of heating elements shown in dotted lines (start all heating elements on U-phase, V-phase and W-phase). Suppose a current time is T3, then a cumulative operating time of the first, third and fourth groups are T3-T1, a cumulative operating time of the second group is T2-T1, a cumulative operating time of the fifth group is T3-T2. The starting priorities of the groups of heating elements are dynamically adjusted according to length of the cumulative operating times. For example, when T3-T2 is less than T2-T1 and T2-T1 is less than T3-T1, the starting priority of the fifth group is adjusted to be highest, the starting priority of the second group is adjusted to be secondarily highest, and the starting priorities of the first, third and fourth groups are adjusted to be lowest. In a next time of starting, when 4 groups of heating elements need to be started, the fifth and second groups of heating elements are preferentially started, two groups of heating elements are randomly selected from the first, third and fourth groups, calculation of a cumulative operating time of the started heating elements is proceeded, and the starting priorities of the heating elements are dynamically adjusted, which shall not be enumerated herein any further.
In some embodiments, the main circuit current value may also be used to calculate power consumption of the heating device and average power consumption of the heating elements, so as to facilitate management and maintenance by users and maintenance personnel.
FIG. 6 is a schematic diagram of the method for determining a fault of this embodiment. As shown in FIG. 6 , for the M heating elements in an operation state parallelly arranged on a branch of a phase line, the method includes:

- 601: acquiring a main circuit current value of the phase line when the operating state of the heating units is not changed;
- 602: determining whether the main circuit current value is not greater than the first current value, and executing 603-606 when a result of determination is yes, otherwise, execute 607;
- 603: determining that a fault occurs in a heating element in at least one heating unit;
- 604: acquiring a variation value of the main circuit current value caused by turning on/off the switch, and determining the heating element where the fault occurs according to the variation value (positioning a fault point);
- 605: controlling the heating element where the fault occurs to stop operating;
- 606: starting a heating element where no fault occurs that is not in operation and is on the same phase line as the heating element where the fault occurs;
- 607: determining whether the main circuit current value is not less than a second current value, and executing 608-609 when a result of determination is yes, otherwise, terminating the process;
- 608: determining that a fault occurs in a switch in at least one heating unit; and
- 609: disconnecting the power switch of the heating device.

In some embodiments, reference may be made to FIG. 5 for an implementation of 604, and implementations of other operations are as described above, which shall not be repeated herein any further.
It should be noted that FIGS. 1, 5 and 6 only schematically illustrate the embodiment of this disclosure; however, this disclosure is not limited thereto. For example, an order of execution of the steps may be appropriately adjusted, and furthermore, some other steps may be added, or some steps therein may be reduced. And appropriate variants may be made by those skilled in the art according to the above contents, without being limited to what is contained in FIGS. 1, 5 and 6 .
It can be seen from the embodiment of this disclosure that whether a fault occurs in a heating element may be determined according to the main circuit current value, and the heating element where the fault occurs may be determined according to the variation value of the main circuit current. Therefore, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability.

Embodiment of the Second Aspect

The embodiment of the second aspect of this disclosure provides a method for determining a fault of a heating device. In this embodiment, description shall be given by taking that an operating current of the heating device is a three phase supply current and the heating device includes three phase lines as an example, that is, when the heating device is operation, each phase line of three phase lines includes at least two (such as M) heating units in an operating state parallelly arranged on branches and each heating unit includes heating element(s) and switch(es) controlling the heating elements.
Furthermore, as described in the embodiment of the first aspect, each of the three phase lines may further include P heating units in a stopped operating state (P is an integer greater than or equal to 0). The P heating units are parallelly arranged with the above M heating units on the branches of the same phase line, that is, on each of the three phase lines, M+P heating units are parallelly arranged on the M+P branches.
Furthermore, as described in the embodiment of the first aspect, each branch may include one heating element or at least two (G, G being an integer greater than or equal to 1) heating elements in series, that is, the heating device may include 3×(M+P)×G heating elements, and on each of the three phase lines, (M+P)×G heating elements are arranged. In other words, the heating device includes M+P groups of heating elements, and one group of heating elements includes 3×G heating elements. As shown in FIG. 3 , the three phase lines are U phase, V phase, and W phase. On each of the three phase lines, M heating elements in an operating state are parallelly arrange on M branches (P=0), and there are M groups of heating elements, each group of heating elements including 3 heating elements. As shown in FIG. 4 , the three phase lines are U phase, V phase, and W phase. On each of the three phase lines, M heating elements in an operating state and P heating elements in a stopped operating state are parallelly arrange on M+P branches, and there are M+P groups of heating elements, each phase line of each group of heating elements including a heating element in series, hence, each group of heating elements includes three heating elements, which shall not be enumerated herein any further.
In some embodiments, the heating elements on the above three phase lines are connected in a star or triangle shape. FIGS. 7 and 8 are schematic diagrams of connection relationships between the heating elements on the three phase lines. As shown in FIG. 7 , the heating elements on the three phase lines are connected in a star shape, and as shown in FIG. 8 , the heating elements on the three phase lines are connected in a triangle shape.
FIG. 9 is a schematic diagram of the method for determining a fault of a heating device. As shown in FIG. 9 , the method includes:

- 901: acquiring a main circuit current value of each phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit in a phase line where the main circuit is located when the main circuit current value is not greater than a first current value; and
- 902: acquiring a variation value of the main circuit current value caused by turning on/off a switch of the phase line where the fault of the heating element occurs, and determining that a fault occurs in a branch where the heating element controlled by the switch is located when the variation value of the main circuit current value is not greater than a preset variation value.

In some embodiments, in implementations of 901-902, main circuit current values of the three phase lines need to be determined respectively. Methods for determining the main circuit current values of the phase lines are identical, and reference may be made to 101-102 in the embodiment the first aspect, with repeated parts being not going to be described herein any further.
For example, in 902, in positioning a fault point for each of the three phase lines, a heating element in operation in the phase line where a fault occurs needed to be sequentially selected, and a first main circuit current value of the heating element in operation and a second main circuit current value after the heating element stops operating are detected in a case where maintaining operating states of other heating elements unchanged, and reference may be made to the embodiment of the first aspect for detailed implementations, which shall not be repeated herein any further.
In some embodiments, each of the three phase lines has its own first current value, second current value and preset current value, and reference may be made to the embodiment of the first aspect for methods for determining the first current value, second current value and preset current value of each phase line, which shall not be repeated herein any further.
It should be noted that FIG. 9 only schematically illustrates the embodiment of this disclosure; however, this disclosure is not limited thereto. For example, an order of execution of the steps may be appropriately adjusted, and furthermore, some other steps may be added, or some steps therein may be reduced. And appropriate variants may be made by those skilled in the art according to the above contents, without being limited to what is contained in FIG. 9 .
It can be seen from the embodiment of this disclosure that whether a fault occurs in a heating element may be determined according to the main circuit current value, and the heating element where the fault occurs may be determined according to the variation value of the main circuit current. Therefore, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability.

Embodiment of the Third Aspect

The embodiment of the third aspect of this disclosure provides an apparatus. FIG. 10 is a schematic diagram of a structure of the apparatus for determining a fault of the embodiment of this disclosure. As shown in FIG. 10 , the apparatus 1000 for determining a fault of the embodiment of this disclosure may include: at least one interface (not shown in FIG. 10 ), a processor (such as a central processing unit) 1001 and a memory 1002, the memory 1002 being coupled to the processor 1001. Wherein, the memory 1002 may store various data, and furthermore, the memory 1002 may store a program 1003 for determining a fault, execute the program 1003 under control of the processor 1001, and store various preset thresholds and predetermined conditions, etc.
In some embodiments, the processor 1001 may execute the method for determining a fault described in the first or the second aspect. For example, the processor 1001 may be configured to: acquire a main circuit current value of the phase line when the operating state of the heating units is not changed, and determine that a fault occurs in a heating element in at least one heating unit when the main circuit current value is not greater than a first current value; and acquire a variation value of the main circuit current value caused by turning on/off the switch, and determine that a fault occurs in a heating element controlled by the switch when the variation value of the main circuit current value is not greater than a preset variation value.
In some embodiments, the processor 1001 may also be configured to: acquire a main circuit current value of each phase line when the operating state of the heating units is not changed, and determine that a fault occurs in a heating element in at least one heating unit in a phase line where the main circuit is located when the main circuit current value is not greater than a first current value; and acquire a variation value of the main circuit current value caused by turning on/off a switch of the phase line where the fault of the heating element occurs, and determine that a fault occurs in a branch where the heating element controlled by the switch is located when the variation value of the main circuit current value is not greater than a preset variation value.
It should be noted that the apparatus 1000 for determining a fault may further include a communication module 1004, or, it does not necessarily include all the parts shown in FIG. 10 . And furthermore, the apparatus 1000 for determining a fault may include parts not shown in FIG. 10 , and reference may be made to related techniques, which shall not be enumerated herein any further. For example, the apparatus 1000 for determining a fault may further include a current transformer used for detecting a main circuit current value, and the processor 1001 is connected to the current transformer for acquiring the main circuit current value.
In this embodiment, the processor 1001 is sometimes referred to as a controller or an operational control, which may include a microprocessor or other processor devices and/or logic devices. The processor 1001 receives input and controls operations of components of the apparatus 1000 for determining a fault.
In the embodiment of this disclosure, the memory 1002 may be, for example, one or more of a buffer memory, a flash memory, a hard drive, a mobile medium, a volatile memory, a nonvolatile memory, or other suitable devices, which may store various data, etc., and furthermore, store programs executing related information. And the processor 1001 may execute the program stored in the memory 1002, so as to realize information storage or processing, etc. Functions of other parts are similar to those of the prior art, which shall not be described herein any further. The parts of the apparatus 1000 for determining a fault may be realized by specific hardware, firmware, software, or any combination thereof, without departing from the scope of this disclosure.
For example, when the heating device is applied to an electric water heater, the processor 1001 and a processor of the electric water heater may be configured separately. For example, the processor 1001 may be configured as a chip connected to the processor of the electric water heater, and both of them may be controlled by each other; or, functions of the processor 1001 may be integrated into the processor of the electric water heater, and the embodiment of this disclosure is not limited thereto.
It can be seen from the embodiment of this disclosure that whether a fault occurs in a heating element may be determined according to the main circuit current value, and the heating element where the fault occurs may be determined according to the variation value of the main circuit current. Therefore, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability.

Embodiment of the Fourth Aspect

The embodiment of the fourth aspect of this disclosure provides an electric water heater. FIG. 11 is a schematic diagram of the electric water heater in the embodiment of this disclosure. As shown in FIG. 11 , the electric water heater 100 includes:

- a heating device 1101 including at least two heating units parallelly arranged on branches of the same phase line, the heating unit includes a heating element and a switch controlling operations of the heating element;
- an apparatus 1102 for determining a fault of the heating device; and
- a waterway assembly 1103, the heating elements being used to heat water in the waterway assembly.

In some embodiments, an operating current of the heating device 1101 may be a single phase power supply current or a three phase power supply current, and reference may be made to the embodiment of the first or the second aspect. Reference may be made to the apparatus 1000 for determining a fault in the embodiment of the third aspect for the implementation of the apparatus 1102 for determining a fault of the heating device, which shall not be described herein any further.
In some embodiments, the apparatus 1102 for determining a fault of the heating device further includes a current transformer for acquiring the main circuit current value, the heating element is a heating rod, and the waterway assembly 1103 includes an inner tank for water storage.
In some embodiments, the apparatus 1102 for determining a fault and a processor of the electric water heater may be configured separately. For example, the apparatus 1102 for determining a fault may be configured as a chip connected to the processor of the electric water heater, and both of them may be controlled by each other; or, functions of the apparatus 1102 for determining a fault may be integrated into the processor of the electric water heater, and the embodiment of this disclosure is not limited thereto.
In some embodiments, the electric water heater may be a commercial high-power electric water heater. For example, the electric water heater may include at least two cascaded sub-electric water heaters, each sub-electric water heater being provided with a waterway assembly and at least one heating unit in an operating state, and at least one heating unit of the sub-electric water heaters in the operating state being connected in parallel on the same phase line.
FIG. 12 is a schematic diagram of a structure of the cascaded electric water heater. As shown in FIG. 12 , the electric water heater 1200 includes at least two cascaded sub-electric water heaters 1201 and an apparatus 1202 for determining a fault of a heating device, each sub-electric water heater 1201 being provided with a waterway assembly 12011 and at least one heating unit 12012 in an operating state, and at least one heating unit 12012 of each sub-electric water heater being connected in parallel on a same phase line. For example, when the operating current is a single-phase power supply current, the electric water heater includes only one phase line, and the heating units in each sub-electric water heater are parallelly arranged on the phase line; and when the operating current is a three-phase power supply current, the electric water heater includes three phase lines, on each of the three phase lines, at least one heating unit in each sub-electric water heater all being parallelly arranged on the phase line, in other words, each sub-electric water heater includes at least one group of heating elements.
In addition, as described in the embodiment of the first aspect, on each of the three phase lines, each sub-electric water heater may include P heating units in a stopped operating state (P is an integer greater than or equal to 0), P heating units being parallelly arranged with the at least one heating unit on branches of the same phase line. Each sub-electric water heater may include one heating element or at least two (G, G is an integer greater than or equal to 1) heating elements in series on each branch. As shown in FIG. 3 , the M groups of heating elements in an operation state may be distributed in each of the sub-electric water heaters 1201, so that each sub-electric water heater 1201 includes at least one group of heating elements in an operation state. As shown in FIG. 4 , the M groups of heating elements in the operating state may be distributed in each of the sub-electric water heaters 1201, so that each sub-electric water heater 1201 includes at least one group of heating elements in the operating state. In addition, the P groups heating elements in the stopped operating state may also be distributed in each of the sub-electric water heaters 1201, and each sub-electric water heater 1201 may include or may not include the above heating elements in the stopped operating state.
In some embodiments, the apparatus 1202 for determining a fault and processors of the sub-electric water heaters may be configured separately. For example, the apparatus 1202 for determining a fault may be configured as a chip connected to the processors of the sub-electric water heaters, and they may be controlled by each other; or, functions of the apparatus 1202 for determining a fault may be integrated into one of the processors of the sub-electric water heaters (such as a first sub-electric water heater), and the embodiment of this disclosure is not limited thereto.
In some embodiments, the apparatus for determining a fault is configured to execute the method for determining a fault described in the embodiment of the first or the second aspect, and reference may be made to the embodiment of the first or the second aspect, which shall not be described herein any further.
It should be noted that the electric water heater 1100 or 1200 may further include components not shown in FIG. 11 or FIG. 12 , and reference may be made to relevant techniques, which shall not be enumerated herein any further.
It can be seen from the above embodiment that whether a fault occurs in a heating element may be determined according to the main circuit current value, and the heating element where the fault occurs may be determined according to the variation value of the main circuit current value. Therefore, diagnosis of faults in a plurality of heating elements in the heating device may be achieved at a low cost and high reliability.
An embodiment of this disclosure provides a computer readable program code, which, when executed in an apparatus for determining a fault or an electric water heater, will cause a master controller to carry out the method for determining a fault as described in the embodiment of the first or the second aspect.
An embodiment of this disclosure provides a computer readable medium, storing a computer readable program code, which will cause an apparatus for determining a fault or an electric water heater to carry out the method for determining a fault as described in the embodiment of the first or the second aspect.
The apparatus for determining a fault described with reference to the embodiments of this disclosure may be directly embodied as hardware, software modules executed by a processor, or a combination thereof. For example, one or more functional block diagrams and/or one or more combinations of the functional block diagrams shown in the drawings may either correspond to software modules of procedures of a computer program, or correspond to hardware modules. Such software modules may respectively correspond to the steps shown in FIGS. 1, 5, 6 and 9 . And the hardware module, for example, may be carried out by firming the soft modules by using a field programmable gate array (FPGA).
The soft modules may be located in an RAM, a flash memory, an ROM, an EPROM, and EEPROM, a register, a hard disc, a floppy disc, a CD-ROM, or any memory medium in other forms known in the art. A memory medium may be coupled to a processor, so that the processor may be able to read information from the memory medium, and write information into the memory medium; or the memory medium may be a component of the processor. The processor and the memory medium may be located in an ASIC. The soft modules may be stored in a memory of a mobile terminal, and may also be stored in a memory card of a pluggable mobile terminal.
One or more functional blocks and/or one or more combinations of the functional blocks in the drawings may be realized as a universal processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware component or any appropriate combinations thereof carrying out the functions described in this application. And the one or more functional block diagrams and/or one or more combinations of the functional block diagrams in the drawings may also be realized as a combination of computing equipment, such as a combination of a DSP and a microprocessor, a plurality of processors, one or more microprocessors in communication combination with a DSP, or any other such configuration.
This disclosure is described above with reference to particular embodiments. However, it should be understood by those skilled in the art that such a description is illustrative only, and not intended to limit the protection scope of the present disclosure. Various variants and modifications may be made by those skilled in the art according to the spirits and principle of the present disclosure, and such variants and modifications fall within the scope of the present disclosure.

Claims

1. A method for determining a fault of a heating device, characterized in that when the heating device comprises at least two heating units in an operating state parallelly arranged on branches of a same phase line and the heating unit comprises a heating element and a switch controlling the heating element, the method comprises:

acquiring a main circuit current value of the phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit when the main circuit current value is not greater than a first current value; and

acquiring a variation value of the main circuit current value caused by turning on/off the switch and determining that a fault occurs in a heating element controlled by the switch when the variation value of the main circuit current value is not greater than a preset variation value.

2. The method according to claim 1, characterized in that the first current value is a preset current value, the preset current value being set based on a total current of all N heating elements in an operation state on a same phase line, or being set based on a total current of N−1 heating elements in the N heating elements; where, N is an integer not less than 2.

3. The method according to claim 1, characterized in that the method further comprises:

updating an acquired main circuit current value to the first current value when it is determined that no heating unit occurs a fault.

4. The method according to claim 1, characterized in that the acquiring a variation value of the main circuit current value caused by turning on/off the switch comprises:

sequentially selecting a heating element in operation, and in a case where operating states of other heating elements are not changed, detecting a first main circuit current value when the heating element is in operation and a second main circuit current value after the heating element stops operating.

5. The method according to claim 4, characterized in that after a switch controlling operation of the heating element is turned on, the first main circuit current value is detected, and after the switch controlling the operation of the heating element is turned off, the second main circuit current value is detected.

6. The method according to claim 1, characterized in that the method further comprises:

controlling the heating element where the fault occurs to stop operating; and

starting a heating element that is not in operation and not occurring a fault, and is on the same phase line as the heating element where the fault occurs.

7. The method according to claim 1, characterized in that the method further comprises:

determining that a fault occurs in a switch in at least one heating unit when the main circuit current value is not less than a second current value.

8. The method according to claim 7, characterized in that the method further comprises: disconnecting a power switch of the heating device after it is determined that a fault occurs in the switch in the at least one heating unit.

9. The method according to claim 1, characterized in that the method further comprises:

calculating a cumulative operating time of the at least two heating units in an operating state parallelly arranged on the branches of a same phase line according to the main circuit current value; and

adjusting starting sequences of the heating elements according to the cumulative operating time.

10. The method according to claim 9, characterized in that the adjusting starting sequences of the heating elements according to the cumulative operating time comprises:

dynamically adjusting starting priorities of the heating elements according to the cumulative operating time; wherein starting priorities of heating elements with long cumulative operating time is low, and starting priorities of heating elements with short cumulative operating time is high; and

starting the heating elements according to the starting priorities.

11. A method for determining a fault of a heating device, characterized in that when an operating current of the heating device is a three phase supply current, each phase line of three phase lines comprises at least two heating units in an operating state parallelly arranged on branches and the heating unit comprises a heating element and a switch controlling the heating element, the method comprises:

acquiring a main circuit current value of each phase line when the operating state of the heating units is not changed, and determining that a fault occurs in a heating element in at least one heating unit in a phase line where the main circuit is located when the main circuit current value is not greater than a first current value; and

acquiring a variation value of the main circuit current value caused by turning on/off a switch of the phase line where the fault of the heating element occurs, and determining that a fault occurs in a branch where a heating element controlled by the switch is located when the variation value of the main circuit current value is not greater than a preset variation value.

12. The method according to claim 11, characterized in that the acquiring a variation value of the main circuit current value caused by turning on/off a switch of the phase line where the fault of the heating element occurs comprises:

sequentially selecting a heating element in operation in the phase line where a fault occurs in heating elements, and detecting a first main circuit current value when the heating element is in operation and a second main circuit current value after the heating element stops operating, in a case where operating states of other heating elements unchanged.

13. The method according to claim 12, characterized in that after the switch controlling the operation of the heating element is turned on, the first main circuit current value is detected, and after the switch controlling the operation of the heating element is turned off, the second main circuit current value is detected.

14. The method according to claim 11, characterized in that the first current value is a preset current value, the preset current value being set based on a total current of all N heating elements in an operation state on a same phase line, or being set based on a total current of N−1 heating elements in the N heating elements; where, N is not less than 2.

15. The method according to claim 11, characterized in that the method further comprises:

when it is determined that no heating element occurs a fault, updating an acquired main circuit current value of each phase line to the first current value to which each phase line corresponds.

16. An apparatus for determining a fault of a heating device, comprising a processor, the processor being configured to execute the method for determining a fault of a heating device as claimed in claim 1.

17. An electric water heater, characterized in that the electric water heater comprises:

a heating device comprising at least two heating units parallelly arranged on branches of a same phase line, the heating unit comprising a heating element and a switch controlling operation of the heating element;

the apparatus for determining a fault of the heating device as claimed in claim 16; and

a waterway assembly, the heating elements being used to heat water in the waterway assembly.

18. The electric water heater according to claim 17, characterized in that an operating current of the heating device is a three phase power supply current, each of the three phase lines comprises at least two heating units parallelly arranged in a branch, and the heating elements on the three phase lines are connected in a star or triangle shape.

19. The electric water heater according to claim 17, characterized in that the electric water heater comprises at least two cascaded sub-electric water heaters, each sub-electric water heater being provided with a waterway assembly and at least one heating unit, and at least one heating unit of each sub-electric water heater being connected in parallel on a same phase line.

20. The electric water heater according to claim 17, characterized in that,

the apparatus for determining a fault of a heating device further comprises a current transformer for acquiring a main circuit current value, the heating element is a heating rod, and the waterway assembly comprises an inner tank for water storage.