Device and method for condition detection

Abstract

Device (1) for monitoring the condition of a wired electrical appliance (2), comprising: a magnetic field sensor (11) designed to detect a magnetic field at an electrical supply line (21) of the electrical device (2); a memory (12) designed to store reference values ​​for a corresponding magnetic field for a plurality of predetermined operating states of the electrical device (2); a processing device (13) designed to compare the magnetic field detected by the magnetic field sensor (11) with the reference values ​​stored in the memory (12) and to determine an operating state of the electrical device (2) based on the comparison; and a fastening device (16) designed to arrange the magnetic field sensor (11) on the supply line (21) of the electrical device (2), wherein a distance between the supply line (21) of the electrical device (2) and the magnetic field sensor (11) is adjustable in a plurality of defined steps or continuously between a minimum and a maximum distance.

Description

[0001] The present invention relates to a device and a method for condition detection. In particular, the present invention relates to a device and a method for condition detection of a wired electrical device.

[0002] The networking of electrical devices within buildings is becoming increasingly important. Systems already exist for monitoring room temperatures, humidity, water leaks, and other factors. Furthermore, several applications are known that automatically transmit measurement data to an energy supplier. In addition, some applications already exist that monitor a person's activity by analyzing device activity. For example, it's possible to monitor whether a kettle, coffee maker, washing machine, or similar appliance is used regularly. If such a device remains inactive for an extended period, it's reasonable to assume that a resident is deviating from their usual routine and may therefore require external assistance.To monitor the activity of individual devices, the electrical devices can, for example, be equipped with a radio interface so that the devices can regularly transmit their current status to a central location.

[0003] Another way to monitor the activity of an electrical appliance is to place an additional power meter between the wall socket and the appliance's plug. Such devices can detect whether a connected appliance is drawing power, thus indicating that the appliance is active.

[0004] European patent application EP 2 278 344 A2 discloses a wireless current sensor for indirect measurement using magnetic field sensors. For this purpose, several magnetic field sensors are arranged around a power supply cable of an electrical device. These current sensors are arranged in a housing that can be opened to position the current sensor around the power supply cable of the electrical device.

[0005] The monitoring of electrical appliances in a household is described in "MagnoTricorder: What you need to do before leaving home" (M. Uddin et al., AM Digital Library, http: / / dl.acm.org / citation.cfm?2370448). For this purpose, a smartphone with a magnetic field sensor is placed near a fuse box. The smartphone analyzes the magnetic fields in the fuse box and then determines the status of the electrical appliances connected to it.

[0006] EP 0 858 143 A2 discloses a monitoring device for mains-powered household appliances. A detection device determines mains parameters such as voltage, current, frequency, or impedance. These detected mains parameters are compared with stored information, and the operating status of a household appliance is determined from this comparison.

[0007] US 2008 / 0079437 A1 discloses a current monitoring module. For this purpose, current sensors can be arranged on the two conductors of an electrical supply line by means of a two-part housing.

[0008] Therefore, there is a need for a cost-effective and energy-efficient condition monitoring system for a wired electrical device. Furthermore, there is a need for a condition monitoring system for a wired electrical device that is easy to use and simple to install and deploy. Disclosure of the invention

[0009] This is achieved by a device and a method having the features of the independent patent claims. Advantages of the invention

[0010] The present invention involves using a magnetic field sensor on the supply line to detect a magnetic field generated by the current flow in the supply line of an electrical device and to compare this detected magnetic field with previously determined reference values ​​in order to infer the current operating state of the electrical device. Comparing the detected magnetic field values ​​with previously determined reference values ​​allows for a particularly simple, quick, and therefore cost-effective determination of the electrical device's condition. Since such a comparison of detected magnetic field values ​​with reference values ​​can be performed very reliably, the magnetic field sensor used does not require high performance. Therefore, a particularly inexpensive magnetic field sensor can be used, which correspondingly reduces the overall system costs.

[0011] Furthermore, determining the operating states of the electrical device requires selecting from a predefined number of possible states. Since no intermediate states are permitted, the reliability of state detection is increased and the risk of incorrectly detected states is reduced. Predefined operating states could be, for example, the "On" and "Off" states of the electrical device. However, other states are also possible, provided they can be distinguished by a characteristic power or current consumption.

[0012] In one embodiment, the condition detection device further comprises a calibration device designed to determine a reference value for a predetermined operating state of the electrical device from the magnetic field detected by the magnetic field sensor and to store the determined reference value together with the corresponding state in the memory. Such calibration of the condition detection makes it possible to individually adapt the condition detection for each electrical device to be monitored. In particular, this allows the condition monitoring to be easily adapted to devices with different power consumption without requiring any modification to the hardware used. Thus, the condition detection device can be used in a particularly universal manner.

[0013] In another embodiment, the calibration device is designed to update the reference values ​​in the memory when the electrical device is in a known operating state and the corresponding stored reference value in the memory deviates from the magnetic field currently detected by the magnetic field sensor. In this way, the reference values ​​can be updated regularly. External disturbances and influences on the magnetic field can thus be quickly compensated for, ensuring reliable condition detection at all times, even if, for example, the magnetic field at the magnetic field sensor were to change due to external influences.

[0014] In a further embodiment, the calibration device comprises an input device designed to receive user input, wherein the calibration device is designed to determine a reference value and store the determined reference value together with a corresponding predetermined operating state in the memory after the input device has received user input. In this way, particularly simple manual calibration of the state detection device is possible.

[0015] The input device can, for example, have several input elements, each of which is assigned to one of the predetermined operating states. In this way, depending on which of these input elements a user activates, they can simultaneously signal the current operating state of the electrical device being monitored.

[0016] In a further embodiment, the device also includes a mounting device designed to position the magnetic field sensor on the electrical supply cable of the electrical device, wherein the distance between the supply cable of the electrical device and the magnetic field sensor is adjustable. In this way, the magnetic field sensor can be securely positioned at a defined location relative to the supply cable of the electrical device, so that the magnetic field to be detected can be reliably measured depending on the condition of the device. Due to the adjustable distance between the supply cable and the magnetic field sensor, the magnetic field sensor can be positioned relative to the supply cable in such a way that it detects a specific portion of the magnetic field generated by the supply cable. Thus, the detection range of the magnetic field sensor can be adjusted to the intensity of the prevailing magnetic field.The magnetic field sensor therefore only needs a relatively small detection range, which makes the use of relatively inexpensive magnetic field sensors possible. If the electrical device being monitored has a relatively low power rating, only a relatively weak magnetic field will be present on the electrical supply line. In this case, the magnetic field sensor can be positioned relatively close to the supply line. Conversely, if an electrical device with a relatively high power rating is being monitored, a relatively strong magnetic field will be present on the supply line. In this case, the magnetic field sensor can be positioned further away from the supply line and will only detect a relatively small portion of the magnetic field. Therefore, even in this case, a simple magnetic field sensor for relatively weak magnetic fields can be used.

[0017] In one embodiment, the mounting device has a scale that indicates the position of the magnetic field sensor depending on the power of the electrical device being monitored. This allows a user to easily adjust the magnetic field sensor on the mounting device and thus set an optimal operating point.

[0018] In another embodiment, the magnetic field sensor is designed to detect the magnetic field at the power cord of the electrical device three-dimensionally. This three-dimensional detection of the magnetic field in all three spatial directions allows for particularly reliable detection. Preferably, the magnetic field is evaluated separately in all three spatial directions, i.e., the x-direction, y-direction, and z-direction. In this case, separate reference values ​​for the corresponding spatial directions can also be stored in the memory.

[0019] In a further embodiment, the device also includes an interface designed to transmit the state of the electrical device, as determined by the processing device, to a receiving device. Preferably, the interface is a wireless radio interface. Such an interface allows the operating states determined by the device to be forwarded for further processing. This enables a particularly efficient evaluation of the operating states determined by the device.

[0020] In a further embodiment, the interface is also designed to receive a calibration signal, wherein the calibration device is designed to determine a reference value and to store the determined reference value together with a corresponding predetermined operating state of the electrical device in the memory after the interface has received a calibration signal. In this way, the calibration process of the device can be remotely controlled by transmitting calibration signals externally.

[0021] In a further aspect, the present invention also creates a building management system with a device according to the invention for condition detection. Brief description of the drawings

[0022] Further embodiments and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. These show: Fig. 1: a schematic representation of a device for status detection of a wired electrical device according to an exemplary embodiment; Fig. 2: a schematic representation of a device for status detection of a wired electrical device according to a further embodiment; Fig. 3: a schematic representation of application examples of a device for condition detection according to a further embodiment; and Fig. 4: a schematic representation of a flowchart for a method for state detection, as it forms the basis of a further embodiment. Description of exemplary implementations

[0023] Fig. Figure 1 shows a schematic representation of a device 1 for monitoring the condition of a wired electrical appliance 2. The wired electrical appliance 2 is supplied with electrical energy via a power cord 21. For example, the power cord 21 can have a plug 22, which allows the electrical appliance to be connected to a corresponding socket. A device 1 for condition detection is attached to the power cord 21 between the plug 22 and the electrical appliance 2. Preferably, the housing of the condition detection device 1 completely encloses a portion of the power cord 21. For example, the housing of the condition detection device 1 can be designed as a type of clamp or similar. Other housing configurations are also possible.For example, the device 1 for condition detection can also be designed in two parts, with the two parts being connected to each other by means of a clamping connection, screw connection or similar connection.

[0024] The device 1 for condition detection comprises a magnetic field sensor 11, a memory 12, a processing device 13, a calibration device 14 and an interface 15.

[0025] When the electrical device 2 is active and supplied with electrical energy via the supply line 21, a magnetic field is generated along the supply line 21. This magnetic field is detected by the magnetic field sensor 11, and a signal corresponding to the detected magnetic field is forwarded to the processing device 13. Preferably, the magnetic field sensor 11 is a magnetic field sensor that detects the magnetic field to be detected three-dimensionally. Such a magnetic field sensor 13 thus detects magnetic field components in all three spatial directions, i.e., in the x-direction, y-direction, and z-direction. These individual detected magnetic field components can also be fed separately to the processing device 13.

[0026] In memory 12, reference values ​​for a corresponding magnetic field are stored for each of the possible predetermined operating states of the electrical device 2. The predetermined operating states of the electrical device 2 can be, for example, the operating states "On" or "Off". Furthermore, other operating states are also possible, provided they can be determined via a characteristic power consumption of the electrical device 2. In one embodiment, for example, the magnitude of the current power or current consumption can be determined from the resulting magnetic field around the supply line 21. Thus, it can be determined, for example, whether a hairdryer or a fan heater is being operated at reduced power or at full power.

[0027] Alternatively, it is also possible to evaluate fluctuations and variations in the power consumption of the electrical device over time and to infer a specific operating state from this. Corresponding reference profiles can also be stored in memory 12, which can be compared with the curve recorded by the magnetic field sensor 11.

[0028] If the magnetic field sensor 11 is a three-dimensional magnetic field sensor, reference values ​​can also be stored separately for each of the spatial directions.

[0029] The processing device 13 reads the reference values ​​stored in the memory 12 and compares them with the magnetic field detected by the magnetic field sensor 11. The processing device 13 can, for example, be a suitably configured microprocessor. Based on the result of the comparison, the processing device 13 determines a current operating state of the electrical device 2 to be monitored. Preferably, the processing device 13 selects the operating state from the set of predetermined operating states stored in the memory 12 that most closely matches the magnetic field currently detected by the magnetic field sensor. The magnetic field monitored by the magnetic field sensor 11 can be monitored for amplitude, frequency, distance to harmonic oscillations, disturbance amplitudes, etc., and compared with corresponding reference values.It is also possible to evaluate magnetic field vectors in space generated by a three-dimensionally captured magnetic field sensor.

[0030] The evaluation of the operating states of the monitored electrical device 2 can, for example, be performed periodically. For this purpose, the magnetic field around the supply line 21 can be detected by the magnetic field sensor 11 at predetermined time intervals, and the current operating state of the monitored electrical device 2 can then be determined. Alternatively, it is also possible to re-determine the current operating state of the electrical device 2 only when the magnetic field monitored by the magnetic field sensor 11 changes. For example, a re-determination of the current operating state can always be performed when the magnetic field as a whole, or at least a component of the magnetic field, changes by more than a certain threshold value. Furthermore, other event-driven determinations of the operating state are also possible.

[0031] The states determined by the processing device 13 are forwarded to an interface 15. The interface 15 transmits the state received by the processing device 13 to a counterpart. This counterpart could, for example, be a central monitoring or storage unit of a building management system. Other counterparts, such as a central processing unit at a remote location, are also possible. Preferably, the interface 15 is a wireless radio interface that transmits the states of the electrical device 2 determined by the processing device 13 to the counterpart via a radio link. Such a radio link could, for example, be a WLAN connection, a Bluetooth connection, a DECT connection, or another connection according to a known, standardized format, or a proprietary communication link.

[0032] The remote unit can be equipped with a suitable display device that shows the current status of the monitored devices. Additionally or alternatively, the remote unit can also have a further communication interface through which a user can receive the monitoring results from a remote location. For example, a user can contact the remote unit via a smartphone or a computer, such as a tablet PC, to obtain information about the status of the monitored electrical devices.

[0033] To determine the reference values ​​in memory 12 for the first time or to update them if necessary, the state detection device 1 can update the reference values ​​in memory 12. For this purpose, the state detection device 1 has a corresponding calibration device 14. This calibration device 14 generates corresponding reference values ​​based on the magnetic field currently detected by the magnetic field sensor 11 and stores these values, along with a corresponding state, in memory 12. This calibration process can be performed either manually or automatically.

[0034] For example, the calibration device 14 can regularly evaluate the magnetic field values ​​provided by the magnetic field sensor 11 and compare them with the current state of the electrical device 2 being monitored. If the current measured values ​​of the magnetic field sensor 11 deviate from the reference values ​​in the memory 12, the calibration device 14 can generate new reference values ​​accordingly and store them in the memory 12. For example, such an update of the reference values ​​can occur if the reference values ​​in the memory 12 deviate from the values ​​currently determined by the calibration device 14 by more than a predetermined threshold.

[0035] Alternatively, manual calibration is also possible. For this purpose, the calibration device 14 can have one or more input devices 14a, 14b, and 14c. Each of these input devices 14a, 14b, and 14c can be assigned to a predetermined operating state of the electrical device to be monitored. For calibration, a user brings the electrical device 2 to be monitored into one of the predetermined operating states and then activates the corresponding input device 14a, 14b, or 14c. The calibration device 14 then evaluates the magnetic field detected by the magnetic field sensor 11, generates corresponding reference values, and stores these, along with information about the corresponding predetermined operating state, in the memory 12. This process can be performed separately for each of the predetermined operating states.After the calibration process has been carried out for all predetermined states to be detected, all required reference values ​​are stored in memory 12 and the state detection device 1 can then reliably detect the operating states of the electrical device 2.

[0036] Alternatively, a corresponding calibration signal can be transmitted from the remote station to the state detection device 1 via interface 15, and the calibration device 14 can then perform a calibration according to the manual concept described above. Preferably, the calibration signal received by interface 15 contains information about a corresponding predetermined operating state. The remote station from which the calibration signal is transmitted to interface 15 can also have an additional device that provides the user with an indication during the calibration process of which operating state the monitored electrical device 2 must be brought into.

[0037] Fig. Figure 2 shows a further schematic representation of a device 1 for status detection of a wired electrical device 2 according to a further embodiment. The device 1 for status detection in this embodiment is largely identical to the device 1 for status detection of the previously described embodiment. In this case, however, the device 1 for status detection also has a mounting device 16, which makes it possible to attach the magnetic field sensor 11 at a variable distance from the supply line 21. By varying the distance between the magnetic field sensor 11 and the supply line 21, the magnetic field detected by the magnetic field sensor 11 can be adjusted so that it is tailored to the type of magnetic field sensor 11 used. This allows the use of magnetic field sensors that have only a relatively small measuring range for a magnetic field to be detected.If the magnetic field sensor 11 is positioned close to the supply line 21, it detects a large portion of the generated magnetic field. This allows the operating states of electrical devices 2 with relatively low power consumption to be reliably detected. However, if the electrical device 2 has a relatively high power consumption, relatively strong magnetic fields are generated along the supply line 21. To avoid overloading the magnetic field sensor 11, it can be positioned further away from the supply line 21.

[0038] The mounting device 16 for the magnetic field sensor 11 can, for example, have a scale 16a that indicates to the user at which position the magnetic field sensor 11 should be positioned, depending on the power of an electrical device to be monitored. The position of the magnetic field sensor 11 can either be continuously adjusted between a minimum and a maximum distance. Alternatively, the position can also be adjusted in two or more defined steps.

[0039] To further adapt the measuring range of the magnetic field sensor 11 used to the magnetic field generated along the supply line 21, the device 1 for condition detection can also have a flux concentrator (not shown) that concentrates or spreads the magnetic field generated along the supply line 21 with respect to the magnetic field sensor 11. Such a flux concentrator can also be arranged within the device 1 for condition detection in such a way that a user can manually adjust the flux concentrator to adapt it depending on the expected magnetic field.

[0040] To further increase reliability, instead of a single magnetic field sensor 11, several magnetic field sensors 11 can be used, which are arranged, for example, symmetrically around the supply line 21.

[0041] Fig. Figure 3 shows a schematic representation of application cases for a device 1 for condition detection of electrical appliances 2. As shown from Fig. As can be seen in section 3, the electrical devices to be monitored can be any type of electrical device. For example, the electrical devices 2 could be a television or a kettle. An iron, a washing machine, a lamp, or other electrical appliances are also possible.

[0042] Fig.Figure 4 shows a schematic representation of a flowchart for a method 100 for state detection of a wired electrical device 2, as underlying an embodiment of the present invention. In step 110, a magnetic field is detected at the electrical supply line 21 of an electrical device 2. Furthermore, in step 120, reference values ​​for a plurality of predetermined operating states of the electrical device 2 are provided. In step 130, the magnetic field detected by the magnetic field sensor 11 is compared with the provided reference values. Finally, in step 140, an operating state of the electrical device 2 is determined based on this comparison.

[0043] In summary, the present invention relates to a device and a method for detecting the condition of an electrical appliance. A magnetic field is detected along an electrical supply line of the appliance, through which the appliance is powered, using a magnetic field sensor. The detected magnetic field is then compared with previously determined reference values ​​to determine the operating state of the electrical appliance. The determination of the reference values ​​can be individually tailored to the electrical appliance being monitored in a preliminary calibration process.

Claims

[1] Device (1) for monitoring the condition of a wired electrical device (2), comprising: a magnetic field sensor (11) designed to detect a magnetic field on an electrical supply line (21) of the electrical device (2); a memory (12) which is designed to store reference values ​​for a corresponding magnetic field for a plurality of predetermined operating states of the electrical device (2); a processing device (13) designed to compare the magnetic field detected by the magnetic field sensor (11) with the reference values ​​stored in the memory (12) and to determine an operating state of the electrical device (2) based on the comparison; and a fastening device (16) which is designed to arrange the magnetic field sensor (11) on the supply line (21) of the electrical device (2), wherein a distance between the supply line (21) of the electrical device (2) and the magnetic field sensor (11) can be adjusted in a plurality of defined steps or continuously between a minimum and a maximum distance. [2] Device (1) according to claim 1, comprising a calibration device (14) which is designed to determine a reference value for a predetermined operating state of the electrical device (2) from the magnetic field detected by the magnetic sensor (11) and to store the determined reference value together with the corresponding predetermined state in the memory (12). [3] Device (1) according to claim 2, wherein the calibration device (14) is designed to update the reference values ​​in the memory (12) when the electrical device (2) is in a known predetermined operating state and the corresponding stored reference value in the memory (12) deviates from the magnetic field currently detected by the magnetic field sensor (11). [4] Device (1) according to claim 2 or 3, comprising an input device (14a, 14b, 14c) adapted to receive a user input; wherein the calibration device (14) is adapted to determine a reference value and to store the determined reference value together with a corresponding predetermined operating state in the memory (12) after the input device (14a, 14b, 14c) has received a user input. [5] Device (1) according to one of claims 1 to 4, comprising a flux concentrator which is designed to concentrate or expand a magnetic field arising along the supply line (21) with respect to the magnetic field sensor (11). [6] Device (1) according to one of claims 1 to 5, wherein the magnetic field sensor (11) is designed to detect a magnetic field on the supply line (21) of the electrical device (2) three-dimensionally. [7] Device (1) according to one of claims 1 to 6, with an interface (15) which is designed to transmit the operating state of the electrical device (2) determined by the processing device (13) to a receiving device. [8] Device (1) according to claim 7, wherein the interface (15) is further configured to receive a calibration signal, wherein the calibration device (14) is configured to determine a reference value and to store the determined reference value together with a corresponding predetermined operating state in the memory (12) after the interface (15) has received a calibration signal. [9] Building management system with a device (1) according to one of claims 1 to 8. [10] Method (100) for monitoring the condition of a wired electrical device (2), comprising the steps: Arranging a magnetic field sensor (11) on the supply line (21) of the electrical device (2), wherein the distance between the supply line (21) of the electrical device (2) and the magnetic field sensor (11) can be adjusted in a plurality of defined steps or continuously between a minimum and a maximum distance; Detecting (110) a magnetic field on an electrical supply line (21) of the electrical device (2) by means of the magnetic field sensor (11); Providing (120) reference values ​​for a plurality of predetermined operating states of the electrical device (2); Comparing (130) the magnetic field detected by the magnetic field sensor (11) with the provided reference values; and Determining (140) an operating state of the electrical device (2) based on the comparison.

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