The present disclosure relates to the field of automobiles. More particularly, the present disclosure relates to a system and a method for health monitoring and estimation of remaining useful life of a motor in an electric vehicle or a hybrid vehicle.
BACKGROUND
[002] The information in this section merely provides background information related to the present disclosure and may not constitute prior art(s) for the present disclosure.
[003] Vehicles, such as, but not limited to, motorized scooters, motorcycles, cars, etc., have a plurality of components and assemblies, inter alia, a power unit. The power unit is adapted to provide the necessary power to the wheels, to drive the vehicle. The power unit may be electrically powered and/or powered by any other fuel like petrol, diesel, etc. for its functioning.
[004] Electric vehicles have an electric motor such as an Interior Permanent Magnet (IPM) Motor to provide necessary power to the wheels. These motors have high torque density (torque/mass or torque/volume), high power density, faster dynamic response, high efficiency and better power factor as compared to its other counterparts, which make it as a better choice for electric vehicle application. However, electrical fault(s) can cause such electric motors to fail. One such failures can be insulation failure which may be initiated by thermal stress, electrical stress, mechanical stress, environmental stress, etc. Further, an inter-turn short circuit fault is mostly initiated by winding insulation degradation which may be the result of one or all the stresses mentioned above. In turn-to-turn fault, two or more number of turns of a coil are short circuited which cause high current to flow in the short circuited portion and this results in the increase of winding temperature, and then in turn insulation degradation and inter-turn short circuit fault.
[005] In such a scenario where the motor of an electric vehicle has developed fault as mentioned above, the rider or driver of the electric vehicle will not be aware of the fault until a sudden failure or breakdown of the vehicle. This may be very unwelcoming scenario and dangerous at the same time.
[006] Hence, there is a need for an early fault detection and diagnosis of the electric motor. Also, there is a need to inform a rider or driver of remaining useful life of the electric motor to prevent any catastrophic failures.

[007] The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the prior art.
SUMMARY
[008] The present disclosure overcomes one or more shortcomings of the prior art and provides additional advantages discussed throughout the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
[009] Pursuant to the embodiments of the present disclosure, in an aspect, a method for estimating Remaining Useful Life (RUL) of a motor is disclosed. The method comprises measuring stator current values of the motor at a plurality of time intervals, calculating third harmonic current values for the measured stator current values, and estimating the RUL of the motor based on the calculated third harmonic current values.
[010] In one non-limiting embodiment of the present disclosure, the method for estimating Remaining Useful Life (RUL) of a motor further comprises selecting a pair of third harmonic current values among the calculated third harmonic current values, calculating a threshold time (tth) based on a pre-determined threshold current value (Ith), and estimating the RUL of the motor based on the calculated threshold time (tth).
[011] In yet another non-limiting embodiment of the present disclosure, the threshold time (tth) is defined as time when the third harmonic current value reaches the threshold current value (Ith), and is defined by: tth=(l/b)*\n(\th/a) wherein: "Ith" represents the threshold value of the third harmonic current value, "tth" represents the threshold time, and "a" and "b" represent variables.
[012] In yet another non-limiting embodiment of the present disclosure, the RUL is estimate by calculating the difference between the threshold time (tth) and time (tn).
[013] In yet another non-limiting embodiment of the present disclosure, the method for estimating Remaining Useful Life (RUL) of a motor further comprises selecting the pair of third harmonic current values having variation greater than a pre-defined limit.

[014] In another non-limiting embodiment of the present disclosure, a system to estimate Remaining Useful Life (RUL) of a motor is disclosed. The system comprises a current measuring unit configured to measure stator current values of the motor at a plurality of time intervals, a storage unit operationally coupled with the current measuring unit. The storage unit is configured to store the measured stator current values of the motor. The system further comprises a life estimation unit operationally coupled with the current measuring unit and the storage unit. The life estimation unit is configured to calculate third harmonic current values for the measured stator current values and estimate the RUL of the motor based on the calculated third harmonic current values.
[015] In another non-limiting embodiment of the present disclosure, the life estimation unit of the system is further configured to select a pair of third harmonic current values among the calculated third harmonic current values, calculate a threshold time (tth) based on pre-determined a threshold current value (Ith), and estimate the RUL of the motor based on the calculated threshold time (tth).
[016] In yet non-limiting embodiment of the present disclosure, the threshold time (tth) is defined as time when the third harmonic current value reaches the threshold current value (Ith), and is defined by: tth=(l/b)*\n(\th/a) wherein: "Ith" represents the threshold value of the third harmonic current value, "tth" represents the threshold time, and "a" and "b" represent variables.
[017] In yet another non-limiting embodiment of the present disclosure, the RUL is estimate by calculating the difference between the threshold time (tth) and time (tn).
[018] In yet another non-limiting embodiment of the present disclosure, the life estimation unit of the system is further configured to estimate the RUL by calculating the difference between the threshold time (tth) and time (tn).
[019] In yet another non-limiting embodiment of the present disclosure, the life estimation unit of the system is further configured to select the pair of third harmonic current having variation greater than a pre-defined limit.
[020] In yet another non-limiting embodiment of the present disclosure, a method for detecting a fault in a motor is disclosed. The method comprises measuring stator current value of the motor, calculating third harmonic current value for the measured stator current

value, and detecting the fault in the motor based on the calculated third harmonic current value.
[021] In yet another non-limiting embodiment of the present disclosure, the method for detecting a fault in a motor further comprises comparing the calculated third harmonic current value with a pre-determined threshold current value and detecting fault in the motor if the calculated third harmonic current value is greater than the pre-determined threshold current value.
[022] In yet another non-limiting embodiment of the present disclosure, a system to detect a fault in a motor is disclosed. The system comprises a current measuring unit configured to measure stator current value of the motor and a storage unit operationally coupled with the current measuring unit. The storage unit is configured to store the measured stator current value of the motor. The system further comprises a fault detection unit operationally coupled with the current measuring unit and the storage unit. The fault detection unit is configured to calculate third harmonic current value for the measured stator current value and detect the fault in the motor based on the calculated third harmonic current value.
[023] In yet another non-limiting embodiment of the present disclosure, the fault detection unit of the system is further configured to compare the calculated third harmonic current value with a pre-determined threshold current value, and detect fault in the motor if the calculated third harmonic current value is greater than the pre-determined threshold current value.
[024] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.
[025] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF FIGURES
[026] The novel features and characteristics of the disclosure are set forth in the description. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following

description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
[027] FIG. 1 illustrates a block diagram of an exemplary vehicle in accordance with an embodiment of the present disclosure.
[028] FIG. 2 A illustrates an exemplary fault loop resistance of the faulty part of inter-turn winding, in accordance with an embodiment of the present disclosure.
[029] FIG. 2B illustrates a graph depicting decrease in fault loop resistance over a period of time (days), in accordance with an embodiment of the present disclosure.
[030] FIG. 2C illustrates a graph depicting an exponential decreasing curve with respect to decreasing fault loop resistance.
[031] FIG. 2D illustrates a bar graph depicting increase in third harmonic stator current fault loop resistance with decreasing fault loop resistance.
[032] FIG. 3 illustrates by way of a block diagram a system to estimate Remaining Useful Life (RUL) of a motor, in accordance with an embodiment of the present disclosure.
[033] FIG. 4 illustrates a graph used to determine predicted life of a motor based on increase in third harmonic of stator current as a fault indicator over a period of time (days), in accordance with an embodiment of the present disclosure.
[034] FIG. 5 A illustrates an exemplary graph used to determine predicted life of a motor using eight points for curve fitting, in accordance with an embodiment of the present disclosure.
[035] FIG. 5B illustrates an exemplary graph used to determine predicted life of a motor using nine points for curve fitting, in accordance with an embodiment of the present disclosure.
[036] FIG. 6 illustrates by way of block diagram a system to detect a fault in a motor, in accordance with an embodiment of the present disclosure.

[037] FIG. 7 illustrates by way of a flow diagram a method for estimating Remaining Useful Life (RUL) of a motor, in accordance with an embodiment of the present disclosure.
[038] FIG. 8 illustrates by way of a flow diagram a method for detecting a fault in a motor, in accordance with an embodiment of the present disclosure.
[039] Skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of embodiments of the present disclosure.
DETAILED DESCRIPTION
[040] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the FIGS, and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure as defined by the appended claims.
[041] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[042] In the present disclosure, the term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
[043] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system

or method proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
[044] The terms like "at least one" and "one or more" may be used interchangeably or in combination throughout the description.
[045] While the present disclosure is illustrated in the context of a vehicle, however, method and system for estimating Remaining Useful Life (RUL) of a motor and method and system for detecting a fault in a motor, and aspects and features thereof can be used with other type of vehicles or motors as well. The terms "vehicle", "two-wheeled vehicle", "electric vehicle", "EV" and "motorcycle" have been interchangeably used throughout the description. The term "vehicle" comprises vehicles such as motorcycles, scooters, bicycles, mopeds, scooter type vehicle, and the like.
[046] Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals will be used to refer to the same or like parts. Embodiments of the disclosure are described in the following paragraphs with reference to FIGS. 1 to 8. In FIGS. 1 to 8, the same element or elements which have same functions are indicated by the same reference signs.
[047] Referring to FIG. 1, an exemplary vehicle 100 according to an embodiment of the present disclosure is disclosed. The vehicle 100 may comprise a motor 102, a user Interface 104, RUL estimation system 106 and fault detection system 108. In some embodiment of the present disclosure, the motor 102 may be an Interior Permanent Magnet (IPM) motor, but not limited thereto. In an exemplary embodiment of the present disclosure, those skilled in the art will appreciate that the IPM motor 102 may comprise one or more electrical components such as a stator, a rotor, coil winding, etc. The stator is the stationary electrical component consisting of a group of individual electro-magnets arranged in such a way that they form a hollow cylinder, with one pole of each magnet facing toward the centre of the group of the electro-magnets. The rotor is the rotating electrical component of the motor 102 consisting of a group of electro-magnets arranged around a cylinder, with the poles facing toward the stator poles. The rotor is located inside the stator and is mounted on the motor's shaft.
[048] In some embodiment of the present disclosure, the objective of these motor components is to make the rotor rotate which in turn will rotate the motor shaft. The coil
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of the motor. As mentioned above, the inter-turn short circuit fault in the coil winding is mostly initiated by winding insulation degradation which may be the result of one or all the stresses mentioned above. In turn-to-turn fault, two or more number of turns of a coil in the coil winding are short circuited which cause high current to flow in the short circuited portion and this results in the increase of winding temperature, and then in turn insulation degradation and inter-turn short circuit fault. In some embodiment of the present disclosure, the vehicle 100 may be a two-wheeled configuration or a multi-wheeled configuration, such as a three-wheeled configuration, a four-wheeled configuration, etc. In accordance with the present disclosure, all the entities such as the motor 102, the user interface 104 and the systems 106, 108 are interconnected with each other. In some embodiment of the present disclosure, the user interface 104 may be a display console of the vehicle 100 and/or a portable device such as cellular telephones, portable digital assistants (PDAs), palmtop computers, and other portable electronic devices. The user interface 104 may be adapted to display information relating to the motor 102 to the rider or driver. The user interface 104 may comprise additional components, such as, LCD, GPS, graphical user interface (GUI), etc., without limiting the scope of the present disclosure.
[049] According to an embodiment, the RUL estimation system 106 is configured to estimate Remaining Useful Life (RUL) of the motor 102 and the fault detection system 108 is configured to detect a fault in the motor 102. The systems 106, 108 measure the stator current and based on the measured current, RUL of the motor 102 is estimated and a fault in the motor 102 is detected. According to an exemplary embodiment, the systems 106 and 108 may comprise one or more sensors to acquire current and voltage information of the motor 102. According to an embodiment, the one or more sensors may be Magnetic current sensors (MCS), Hall-effect current sensors, or any other suitable sensor(s) to acquire current and voltage information.
[050] According to an embodiment, the fault in the motor 102 may be due to inter-turn short circuit faults. The insulation resistance of the faulty part of the winding may be represented as fault loop resistance (rf) as shown in FIG. 2A. In general, the insulation resistance protects the motor 102 from short circuit which may lead to complete breakdown of the vehicle 100. Further, in FIG. 2A, winding 202 represents faulty winding having the fault loop resistance rf and current If. Further, windings 204 and 206 represents non-faulty i.e., healthy windings of the electric motor 102. Whenever a fault occurs in a winding of the motor 102, the insulation resistance i.e., the fault loop resistance (/y) decreases which results as increase in current (zV) flowing through the winding 202. Gradually, as the value

of the fault loop resistance (/y) decreases over a period of time the value of current (//) increases.
[051] An exemplary graph representing decrease in the fault loop resistance (rf) over a period of time (days) is illustrated in FIG. 2B. For example, when the fault initially occurs i.e., on day zero, the value of the fault loop resistance (/y) is the maximum i.e., more than 120 ohms (Q). However, as the fault increases in the motor 102, the fault loop resistance decreases and eventually the value of the fault loop resistance (/y) reaches to approximately zero i.e., the day when the motor 102 stops working thereby causing complete failure of the vehicle 100. This decrease in the fault loop resistance can be represented by an exponential decreasing curve as shown in FIG. 2C. The exponential curve may be represented by following expression.
y = a * exp"bx
[052] In the above expression, "y" is the function of the exponential curve representing the fault loop resistance rf, "a" and "b" are variables, and "x" represents the time. In other way, the variation in the fault loop resistance can be represented by:
rf = a * exp"bt
[053] Since the current is inversely proportional to the resistance, when the resistance decreases, the current increases. In other words, when the fault loop resistance rf decreases exponentially over time, the current flowing through the fault winding increases exponentially. The current may be represented by following expression.
[054] In the above expression, "y" is the function of the exponential curve representing the current If, "a" and "b" are variables, and "x" represents the time. In other way, the variation in the fault loop current can be represented by:
If = a * expbt
[055] According to an embodiment, the first, second harmonic components of stator currents do not change significantly when the fault in the motor 102 increases. However, third harmonic component of stator currents increases significantly when the fault in the motor increases. Thus, third harmonic component of stator currents may be used as a reliable factor for fault indication and may also be used for the purpose of estimation of the

remaining useful life of the motor 102. In an exemplary aspect of the present disclosure, the third harmonic component of stator current for healthy and faulty motors may be calculated by using various techniques such as Fourier transformation technique, but not limited thereto. In an exemplary aspect of the present disclosure, the third harmonic component of the stator current is calculated by the systems 106, 108 based on the stator current measured by the one or more sensors as mentioned above.
[056] To understand same in detail reference may be made to FIG. 2D which shows an exemplary bar graph representing increase in third harmonic of stator current with decrease in the value of the fault loop resistance (/y). It is observed that the value of current increases if the fault loop resistance decreases (increase in fault severity). In an exemplary aspect, when the inter turn winding of the motor 102 is healthy the value of the third harmonic of stator current is approximately 0.96 ampere (A) whereas when the fault occurs the value of the third harmonic of stator current increases to approximately 1.02 ampere (A) and the value of the fault loop resistance (/y) is 100 ohms (Q). Further, when the value of the fault loop resistance (/y) is zero, the value of the third harmonic of stator current increases to approximately 1.16 ampere (A) i.e., the day when the motor 102 stops working thereby causing complete failure of the vehicle 100.
[057] The process of detecting a fault in the motor 102 and estimating RUL of the motor is explained below in more detail.
[058] Now referring to FIG. 3, an exemplary system 106 used to estimate RUL of the motor is shown in accordance with an embodiment of the present disclosure. The system 106 may comprise a current measuring unit 302, a storage unit 304 and a life estimation unit 306. All these unit 302-306 are communicatively coupled with each other. In an embodiment of the present disclosure, the current measuring unit 302 may comprises suitable arrangement/components to measure stator current of the motor 102, known to a person skilled in the art and is not explained for the sake of brevity. In an embodiment, the life estimation unit 306 may comprise one or more processors and memory.
[059] The current measuring unit 302 is configured to measure stator current values of the motor 102 at a plurality of time intervals. In an embodiment, the time intervals may be randomly selected. In another embodiment, the time intervals are selected such that significant variation (more than a threshold value) in the current is captured. The current

measuring unit 302 is operationally coupled with the storage unit 304. The measured stator current values of the motor 102 may be stored in the storage unit 304.
[060] Further, the life estimation unit 306 is operationally coupled with the current measuring unit 302 and the storage unit 304. The life estimation unit 306 may access the current values and calculate third harmonic current values for the measured stator current values. Further, the life estimation unit 306 may be configured to select a pair of third harmonic current values among the calculated third harmonic current values. The life estimation unit 306 may select third harmonic current values, among the calculated third harmonic current values, having variation greater than a pre-defined limit. In an aspect of the present disclosure, the limit may be defined such that proper variation in current is captured.
[061] Further, based on the selected pair of the third harmonic current values, the life estimation unit 306 may apply curve fitting technique to determine the variables "a" and "b" of the curve representing the variation in the current. According to an embodiment, the life estimation unit 306 may consider multiple points such as eight points or nine points to apply the curve fitting techniques to increase the accuracy of the system.
[062] Further, the life estimation unit 306 may calculate a threshold time (tth) based on a pre-determined threshold current value (Ith). The pre-determined threshold current value (Ith) may be a value which is already determined based on current or resistance data of the motor 102. The threshold time (tth) is defined as time when the third harmonic current value reaches a threshold current value (Ith), and may be defined by following expression.
tth=(l/b)*ln(lth/d)
In the above expression, "Ith" represents the threshold value of the third harmonic current value, "tth" represents the threshold time, and "a" and "b" represent variables.
[063] After determining the threshold time (tth), the life estimation unit 306 may estimate the remaining useful life (RUL) of the motor 102 by calculating the difference between the threshold time (tth) and present time (tn). The threshold time represents the time when the motor 102 completely breaks down. FIG. 4 shows an exemplary graph representing the above-mentioned expression indicative of the exponential curve. Denoted by the dotted line in the graph of FIG. 4 is the slope of predicted life of the motor 102 and denoted by the solid curve in the graph of FIG. 4 is the actual life of the motor 102.

[064] In this manner, the system 106 may efficiently estimate RUL of the motor which may be provided to the user of vehicle to alert the user in advance via the user interface/display of the vehicle. According to an embodiment, the system may consider multiple points such as eight points or nine points to apply the curve fitting techniques to increase the accuracy of the system. In an embodiment, the points refer to time instances where the current value is measured.
[065] FIG. 5A shows an exponential curve representing variation in current which is plotted using eight points using the curve fitting technique to estimate the predicted life of the motor 102. As shown in FIG. 5A, the difference between actual and predicted life has been determined to be approximately 3 days i.e., actual life is 16.64 days and estimated RUL is 19.66 days. Further, FIG. 5B shows an exponential curve representing variation in current which is plotted using nine points curve fitting technique to estimate the predicted life of the motor 102. As shown in FIG. 5B, the difference between actual and predicted life has been determined to be approximately 0.17 days i.e., actual life is 10.84 days and estimated RUL is 10.67 days. Therefore, as disclosed by the present disclosure, the difference between actual and predicted life i.e., error may be reduced when the number of points in time i.e., values of "x" is increased while plotting the exponential curve by using any curve fitting technique.
[066] Now referring to FIG. 6, an exemplary system 108 to detect the fault in the motor 102 in accordance with an embodiment of the present disclosure. The system 108 may comprise a current measuring unit 602, a storage unit 604 and a fault detection unit 606. The current measuring unit 602 may measure stator current values of the motor 102 as described above and the the measured stator current values of the motor 102 may be stored in the storage unit 604. In an aspect of the present disclosure, the stator current values may be measured by the current measuring unit 602 using the one or more sensors such as Magnetic current sensors (MCS), Hall-effect current sensors, or any other sensor(s) to acquire current and voltage information. In an embodiment, the fault detection unit 606 may comprise one or more processors and memory.
[067] Further, the fault detection unit 606 may calculate third harmonic current value for the measured stator current value. The fault detection unit 606 may compare the calculated third harmonic current value with a pre-determined threshold current value. If the third harmonic current value is greater than the pre-determined threshold current value, the fault

detection unit 606 may determine that there exists a fault in the motor 102. According to an embodiment, the pre-determined threshold current value may be calculated based on the third harmonic current values of the healthy motors. In this manner, the system can efficiently detect the fault in the motor as soon as fault occurs in the motor 102 and may alert the user for the same via the user interface/display of the vehicle.
[068] According to a non-limiting exemplary embodiment, the system 106 may perform the functionality of the system 108. Also, the functionality of the life estimation unit 306 of system 106 and the fault detection unit 606 of system 108 may be performed by common one or more processors.
[069] FIG. 7 is a flow diagram illustrating an example method 700 for estimating Remaining Useful Life (RUL) of a motor in accordance with various aspects of the present disclosure. In an aspect of the present disclosure, the system 106 may perform the method 700. Although the operations described below are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation.
[070] In an aspect of the present disclosure, at block 702, the method 700 may measure stator current values of the motor at a plurality of time intervals. In an aspect of the present disclosure, the stator current values may be measured by the current measuring unit 302 using the one or more sensors such as Magnetic current sensors (MCS), Hall-effect current sensors, or any other sensor(s) to acquire current and voltage information. At block 704, the method 700 may calculate third harmonic current values for the measured stator current values. In an aspect of the present disclosure, the third harmonic current values for the measured stator current values may be calculated by the life estimation unit 306. At block 706, the method 700 may estimate the RUL of the motor based on the calculated third harmonic current values. In an aspect of the present disclosure, the RUL of the motor based on the calculated third harmonic current values may be estimated by the life estimation unit 306.
[071] In some aspect of the present disclosure, the method 700 may select a pair of third harmonic current values among the calculated third harmonic current values. In an aspect of the present disclosure, the method 700 may select the pair of third harmonic current values having variation greater than a pre-defined limit. In an aspect of the present

disclosure, the pair of third harmonic current values may be selected by the life estimation unit 306. In an aspect of the present disclosure, the pre-defined limit may be a value which may be based on the configuration and/or simulation based data of the motor. In an aspect of the present disclosure, the method 700 may calculate a threshold time (tth) based on a pre-determined threshold current value (Ith). In an aspect of the present disclosure, the threshold time (ta,) may be calculated by the life estimation unit 306. In an aspect of the present disclosure, the method 700 may estimate the RUL of the motor based on the calculated threshold time (tth). In an aspect of the present disclosure, the RUL of the motor may be estimated by the life estimation unit 306.
[072] The threshold time (tth) is defined as time when the third harmonic current value reaches a threshold current value (Ith), and is defined by:
tth=(l/b)*ln(lth/d)
Where, "Ith" represents the threshold value of the third harmonic current value, "tth" represents the threshold time, and
"a" and "b" represent variables i.e., values calculated based on the third harmonic of stator current at two different times.
[073] In an aspect of the present disclosure, the method 700 may estimate the remaining useful life (RUL) of the motor by calculating the difference between the threshold time (tth) at which the motor completely breaks down and and present time (tn).
[074] FIG. 8 is a flow diagram illustrating an example method 800 for detecting a fault in a motor, in accordance with various aspects of the present disclosure. In an aspect of the present disclosure, the system 108 is configured to perform the method 800. Although the operations described below are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation.
[075] In an aspect of the present disclosure, at block 802, the method 800 may measure stator current values of the motor. In an aspect of the present disclosure, the stator current value of the motor by the current measuring unit 602 using the one or more sensors such as Magnetic current sensors (MCS), Hall-effect current sensors, or any other sensor(s) to acquire current and voltage information. At block 804, the method 800 may calculate third harmonic current value for the measured stator current value. In an aspect of the present

disclosure, the third harmonic current value may be calculated by the fault detection unit 606. At block 806, the method 800 may detect the fault in the motor based on the calculated third harmonic current value. In an aspect of the present disclosure, the fault in the motor may be detected by the fault detection unit 606.
[076] In an aspect of the present disclosure, the method 800 may compare the calculated third harmonic current value with a pre-determined threshold current value. In an aspect of the present disclosure, the pre-determined threshold current value may be a value which may be based on the configuration and/or simulation based data of the motor.
[077] In an aspect of the present disclosure, the method 800 may detect fault in the motor if the calculated third harmonic current value is greater than the pre-determined threshold current value.
[078] In this manner, the techniques disclosed in the present disclosure may efficiently detects the fault in the motor and may also estimate the RUL of the motor which may be presented to the user of the vehicle via the user interface/display of the vehicle.
[079] The various embodiments of the present disclosure have been described above with reference to the accompanying drawings. The present disclosure is not limited to the illustrated embodiments; rather, these embodiments are intended to fully and completely disclose the subject matter of the disclosure to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity.
[080] Herein, the terms "attached", "connected", "interconnected", "contacting", "mounted", "coupled" and the like can mean either direct or indirect attachment or contact between elements, unless stated otherwise.
[081] Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression "and/or" includes any and all combinations of one or more of the associated listed items.
[082] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms

"comprises", "comprising", "includes" and/or "including" when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
[083] While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

EQUIVALENTS;
[084] The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[085] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
[086] Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
[087] The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

We claim;

1. A method for estimating Remaining Useful Life (RUL) of a motor, the method
comprising:
measuring stator current values of the motor at a plurality of time intervals;
calculating third harmonic current values for the measured stator current values; and
estimating the RUL of the motor based on the calculated third harmonic current values.
2. The method of claim 1, further comprising:
selecting a pair of third harmonic current values among the calculated third harmonic current values;
calculating a threshold time (tth) based on a pre-determined threshold current value (Ith); and
estimating the RUL of the motor based on the calculated threshold time (tth).
3. The method of claim 2, wherein the threshold time (tth) is defined as time when the third
harmonic current value reaches the threshold current value (Ith), and is defined by:
tth=(l/b)*ln(lth/d)
wherein:
"Ith" represents the threshold value of the third harmonic current value, "tth" represents the threshold time, and "a" and "b" represent variables.
4. The method of claim 2, wherein the RUL is estimate by calculating the difference between the threshold time (tth) and time (tn).
5. The method of claim 2, wherein selecting the pair of third harmonic current values comprises selecting third harmonic current values having variation greater than a pre-defined limit.
6. A system to estimate Remaining Useful Life (RUL) of a motor, the system comprises:

a current measuring unit configured to measure stator current values of the motor at a plurality of time intervals;
a storage unit operationally coupled with the current measuring unit, wherein the storage unit is configured to store the measured stator current values of the motor; and
a life estimation unit operationally coupled with the current measuring unit and the storage unit,
wherein the life estimation unit is configured to calculate third harmonic current values for the measured stator current values, and estimate the RUL of the motor based on the calculated third harmonic current values.
7. The system of claim 6, wherein the life estimation unit is further configured to:
select a pair of third harmonic current values among the calculated third harmonic current values;
calculate a threshold time (tth) based on a pre-determined threshold current value (Ith); and
estimate the RUL of the motor based on the calculated threshold time (tth).
8. The system of claim 7, wherein the threshold time (tth) is defined as time when the third
harmonic current value reaches a threshold current value (Ith), and is defined by:
tth=(l/b)*\n(lth/a)
wherein:
"Ith" represents the threshold value of the third harmonic current value, "tth" represents the threshold time, and "a" and "b" represent variables.
9. The system of claim 7, wherein the life estimation unit is configured to estimate the RUL
by calculating the difference between the threshold time (tth) and time (tn).
10. The system of claim 7, wherein the life estimation unit is configured to select the pair of third harmonic current by selecting third harmonic current values having variation greater than a pre-defined limit.
11. A method for detecting a fault in a motor, the method comprising:
measuring stator current value of the motor;

calculating third harmonic current value for the measured stator current value; and
detecting the fault in the motor based on the calculated third harmonic current value.
12. The method of claim 11, further comprising:
comparing the calculated third harmonic current value with a pre-determined threshold current value; and
detecting fault in the motor if the calculated third harmonic current value is greater than the pre-determined threshold current value.
13. A system to detect a fault in a motor, the system comprises:
a current measuring unit configured to measure stator current value of the motor;
a storage unit operationally coupled with the current measuring unit, wherein the storage unit is configured to store the measured stator current value of the motor; and
a fault detection unit operationally coupled with the current measuring unit and the storage unit,
wherein the fault detection unit is configured to calculate third harmonic current value for the measured stator current value and detect the fault in the motor based on the calculated third harmonic current value.
14. The system of claim 13, wherein the fault detection unit is further configured to:
compare the calculated third harmonic current value with a pre-determined threshold current value; and
detect fault in the motor if the calculated third harmonic current value is greater than the pre-determined threshold current value.