DESC:AUTO-CALIBRATION IN ELECTRIC VEHICLE
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority from Indian Provisional Patent Application No. 202321065121 filed on 28/09/2023, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
Generally, the present disclosure relates to calibration of vehicle(s). Particularly, the present disclosure relates to a system and method for auto-calibration of electric vehicle(s).
BACKGROUND
Auto-calibration in Electric Vehicles (EVs) refers to a mechanism of automatically adjusting the parameters and settings of the vehicle to optimize its performance. The parameters and settings as mentioned herein may include, but not limited to, Battery Management System (BMS) Calibration, motor and motor controller calibration, thermal management system calibration, and regenerative braking calibration.
Conventionally, the electric vehicles employ an incremental encoder for the calibration of the vehicles. The incremental encoder comprises a disk attached to a rotating shaft of the motor and a sensor. The disk is marked with lines or slots, that interact with the sensor. Further, as the disk rotates, the encoder generates electrical signals as continuous pulses to indicate the steps of movement of the shaft. Subsequently, a conversion system interprets the pulses to determine the shaft movement from its starting/previous position. Therefore, the incremental encoders convert the physical rotation of the shaft into a digital form of pulses, enabling machines to measure the motion.

However, there are certain underlining problems associated with the above-mentioned existing mechanism of calibration of the vehicles. For instance, the incremental encoders have a fixed resolution, and therefore, provide only a limited number of pulses per revolution. Consequently, the limited number of pulses restrict the accuracy of position or speed measurement, particularly in the applications where a very high precision is required. Further, the incremental encoders measure the change in position (relative position) but do not provide the absolute position information of the rotor. Therefore, in case of power loss, the system requires a reset, which results in the loss of the position information.
Therefore, there exists a need for a calibration system for an electric vehicle that is accurate and overcomes one or more problems as mentioned above.
SUMMARY
An object of the present disclosure is to provide a system for auto-calibration of a battery powered vehicle.
Another object of the present disclosure is to provide a method of auto-calibration of a battery powered vehicle.
Yet another object of the present disclosure is to provide a system and method for the auto-calibration of the vehicle, with improved precision and accuracy.
In accordance with a first aspect of the present disclosure, there is provided a system for auto-calibration of a battery powered vehicle, the system comprising:
- at least one poly-phase motor comprising a stator and a rotor;
- a plurality of current sensors;
- at least one rotor position sensor; and
- at least one offset control unit,
wherein the stator comprises a plurality of stator windings and the plurality of current sensors are connected to at least one pair of windings of the plurality of stator windings.
The system and method for auto-calibration of a battery powered vehicle, as described in the present disclosure, is advantageous in terms of providing a system with enhanced precision and accuracy for the auto-calibration of the vehicle. Advantageously, the auto-calibration precisely aligns the rotor(s) in accordance with the operational parameters, and the current supplied to the stator is optimized efficiently for the operating conditions. Consequently, the precise rotor(s) alignment and efficiently optimized current provide an improved auto-calibration mechanism for the vehicle. Therefore, improving the overall efficiency and performance of the vehicle, without any hardware changes.
In accordance with another aspect of the present disclosure, there is provided a method of auto-calibration of a battery powered vehicle, the method comprises:
- sensing current values flowing through at least one pair of windings of a stator of at least one motor, via a plurality of current sensors;
- determining offset current values for the at least one pair of windings, via at least one offset control unit;
- determining a current multiplier value based on the determined offset current values, via the at least one offset control unit;
- determining rotor offset value for a rotor of the at least one motor, via the at least one offset control unit; and
- initiating auto-calibration of the plurality of current sensors and/or of at least one rotor position sensor.
Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments constructed in conjunction with the appended claims that follow.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
Figures 1 illustrates a block diagram of a system for auto-calibration of a battery powered vehicle, in accordance with an embodiment of the present disclosure.
Figure 2 illustrates a flow chart of a method of auto-calibration of a battery powered vehicle, in accordance with another aspect of the present disclosure.
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION
The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
As used herein, the terms “auto-calibration”, “calibration” and “self-calibration” are used interchangeably and refer to a process of automatically adjusting the settings and parameters of a vehicle based on a feedback, periodically for a pre-defined time interval, and/or a pre-defined distance travelled and so forth. The settings and parameters may include (but not limited to) sensor gain, motor torque output, rotor offset, battery charging/discharging, and thermal susceptibility. The auto-calibration is controlled via vehicle electronic control units (ECUs) to maintain optimal performance, accuracy, and efficiency of the vehicle. The auto-calibration improves the efficiency of the vehicle under varying operating conditions, for instance, difficult terrains, temperature variations, and different driving modes.
As used herein, the terms “battery powered vehicle”, “EV”, “electric vehicle”, and “vehicle” are used interchangeably and refer to a vehicle that is driven by an electric motor that draws its electrical energy from a battery and is charged from an external source. The electric vehicle includes both a vehicle that is only driven by the electric motor that draws electrical energy from the battery (all-electric vehicle) and a vehicle that may be powered by an electric motor that draws electricity from the battery and by an internal combustion engine (hybrid vehicle). Moreover, the ‘electric vehicle’ as mentioned herein may include electric two-wheelers, electric three-wheelers, electric four-wheelers, electric trucks, electric pickup trucks, and so forth.
As used herein, the terms “poly-phase motor”, “multi-phase motor”, and “motor” are used interchangeably and refer to any device, or a machine that uses electrical energy to produce rotating motion or mechanical energy. The motor consists of a stator and a rotor. The flow of electrical current through the motor generates a magnetic field that turns the rotor, producing a mechanical movement. Various types of motors may include (but not limited to) DC shunt motors, DC series motors, AC induction motors, AC synchronous motors, and switched reluctance motors. Specifically, a poly-phase motor is powered via a poly-phase AC supply, having multiple sinusoidal voltage waveforms phase-shifted from each other.
As used herein, the term “stator” refers to the stationary part of a polyphase electric motor, consisting of a set of windings or coils energized by a polyphase AC supply. In polyphase motors, particularly in a three-phase motor, the stator generates a rotating magnetic field that interacts with the rotor to produce mechanical motion. The stator of a poly-phase motor contains windings or coils that are connected in a specific pattern to produce the polyphase magnetic field. More particularly, in a three-phase motor, three sets of windings are placed 120 degrees apart from each other to produce three-phase magnetic field.
As used herein, the term “rotor” refers to the rotating part of a polyphase electric motor. The rotor is placed inside the stator and the turning of the rotor starts when the motor is operating. The rotor converts the magnetic field generated by the stator into mechanical motion, which drives the mechanical loads connected to the motor. In an induction motor, the rotating magnetic field produced by the stator induces currents in the rotor. These induced currents generate their magnetic field, which interacts with the stator’s field, initiating the rotor to turn. In a synchronous motor, the rotor contains permanent magnets or is excited with DC current to produce a constant magnetic field that synchronizes with the rotating magnetic field of the stator.
As used herein, the term “current sensor” refers to a device that measures and monitors the electrical current flowing through various parts of the vehicle's electrical system. Further, the accurate current measurement is essential for managing power distribution, optimizing performance, ensuring safety, and improving the overall efficiency of the EV. Specifically, the current sensors detect the current flowing through the stator windings of the motor for an efficient auto-calibration of the vehicle.
As used herein, the term “rotor position sensor” refers to a device that detects the position of the rotor inside a motor. Further, the rotor position sensor measures the angular position or rotational speed of the rotor within an electric motor. The rotor position sensor provides real-time feedback to the motor controller or control unit, enabling precise control of the motor's performance and operation.
As used herein, the terms “offset control unit” and “control unit” are used interchangeably and refer to a device or subsystem that adjusts or aligns the error (offset) or inconsistent bias present in the operational parameters of a system. The offset control unit adjusts the deviations (offset), thereby maintaining accuracy and improving performance of vehicle.
As used herein, the terms “stator windings” and “windings” are used interchangeably and refer to the coils of insulated wire wound around the stator core of an electric motor. The stator windings produce the magnetic field that interacts with the rotor to convert electrical energy into mechanical energy (in motors) or mechanical energy into electrical energy (in generators). The stator windings are supplied with an alternating current (AC) that creates a magnetic field. The magnetic field created interacts with the rotor to produce mechanical motion in the motor.
As used herein, the term “input current” refers to the electrical currents that flow into the rotor windings or conductors of an electric motor. The input currents create the magnetic field in the rotor, which interacts with the stator’s magnetic field to produce mechanical motion. Further, the interaction between the rotor’s magnetic field and the stator’s rotating magnetic field produces torque, which causes the rotor to turn and generate mechanical power.
As used herein, the term “offset current” refers to deviations or biases in the electrical current supplied to the motor. The offset in current measurement may occur due to (but not limited to) measurement errors, calibration issues, or inherent biases in the control system, and may impact the motor's performance and efficiency.
As used herein, the term “current multiplier” refers to a calibration factor in an auto-calibration process of a motor to adjust the measured current values to accurately represent the actual current flowing through the motor. The current multiplier compensates for any measurement errors, biases, or offsets in the current sensing system.
As used herein, the term “rotor offset” refers to the displacement or misalignment of a rotor from its intended or ideal position within a motor. The rotor offset affects the performance, efficiency, and safety of the motor and/or vehicle. Consequently, resulting in mechanical wear, increased friction, unwanted vibrations, noise and so forth.
As used herein, the term “predefined rotor positions” refers to specific locations or orientations of a rotor designed to occupy within a system or mechanism under operational conditions. The predefined rotor positions ensure proper operation, alignment, and performance of the system.
In accordance with a first aspect of the present disclosure, there is provided a system for auto-calibration of a battery powered vehicle, the system comprising:
- at least one poly-phase motor comprising a stator and a rotor;
- a plurality of current sensors;
- at least one rotor position sensor; and
- at least one offset control unit,
wherein the stator comprises a plurality of stator windings and the plurality of current sensors are connected to at least one pair of windings of the plurality of stator windings.
Referring to figure 1, in accordance with an embodiment, there is described a system 100 for auto-calibration of a battery powered vehicle. The system 100 comprises at least one poly-phase motor 102 comprising a stator 104 and a rotor 106, a plurality of current sensors 108A,108B, at least one rotor position sensor 110, and at least one offset control unit 112. Specifically, the stator 104 comprises a plurality of stator windings 114, and the plurality of current sensors 108A,108B are connected to at least one pair of windings of the plurality of stator windings 114.
The plurality of current sensors 108A,108B are connected to at least one pair of stator windings 114 and are configured to sense current values flowing through the at least one pair of stator windings. Further, the offset control unit 112 is configured to receive the sensed current values and compare the sensed current values with input current values. Furthermore, based on the comparison, the offset control unit 112 determines offset current values for at least one pair of stator windings. Advantageously, comparing the sensed current values with input current values enables the offset control unit 112 to precisely detect and quantify deviations or offsets, thus resulting in accurate calibration of the vehicle. Moreover, based on the determined offset current values, the offset control unit 112 computes a current multiplier value. Consequently, the current multiplier value enables the offset control unit 112 to precisely adjust the sensed current values, ensuring more accurate auto-calibration of the current sensors. Further, the above-mentioned precise adjustment enables the dynamic adjustment of sensed current values based on real-time offset data, thereby, improving load management and operational efficiency of the vehicle (and current sensors).
In an embodiment, the plurality of current sensors 108A,108B are configured to sense current values flowing through the at least one pair of windings. The plurality of current sensors 108A,108B enable the offset control unit 112 to receive a series of real-time data (current values). Subsequently, the received real-time data enable the offset control unit 112 to detect offset current values of the current flowing through the stator windings 114. The current offset indicates the deviation of the current from the input current value. Therefore, the sensing of the current values enables the continuous adjustments of the current flowing through the windings and initiates the auto-calibration of the current sensors 108A,108B.
In an embodiment, the at least one offset control unit 112 is configured to receive the sensed current values and compare the sensed current values with input current values. Consequently, based on the comparison, the offset control unit 112 determines offset current values for the at least one pair of windings. Beneficially, the sensed current values (real-time data) enable dynamic adjustments of the current values via auto-calibration to maintain optimal performance of the stator and/or current sensors 108A,108B.
In an embodiment, the at least one offset control unit 112 is configured to compare the received current values with input current values, to determine offset current values for the at least one pair of windings. The comparison of the received current values with the input current values enables the offset control unit 112 to accurately measure the variations or offsets, resulting in precise calibration of the current sensors 108A,108B. Moreover, the deviation of the sensed value from the input current values enables the detection of potential faults within the windings or associated components.
In an embodiment, the at least one offset control unit 112 is configured to determine a current multiplier value based on the determined offset current values. The current multiplier value enables the offset control unit 112 to determine the variation of the sensed current values with the input current values. Consequently, based on the value of the current multiplier, the offset control unit 112 calibrates the current sensor 108A,108B to ensure a more accurate operation and improved measurement fidelity of the current sensors 108A,108B. Further, the offset control unit computes the gain of the current sensors 108A,108B, based on the determined current multiplier value. Consequently, the determined gain of the current sensors 108A,108B enables the offset control unit 112 to optimize the operation of the current sensors 108A,108B and, thereby, perform accurate calibration of the vehicle.
In an embodiment, wherein the at least one offset control unit 112 is configured to initiate the auto-calibration of the plurality of current sensors 108A,108B, based on the determined current multiplier value. The offset control unit 112 initiates the calibration of current sensors 108A,108B based on the current multiplier value, thereby ensuring that each sensor provides accurate and consistent measurements. Further, the auto-calibration enhances the susceptibility of the current sensors ensuring the detection of very small changes in the measured current, which enables the early identification of faulty components.
In an embodiment, the at least one rotor position sensor 110 is configured to sense positions of the rotor 106 based on phase angle of the input current values flowing through the at least one pair of windings. The input currents applied to the stator windings 114 have an orthogonal (90-degree) phase difference, enabling the rotor 106 to rotate based on the input current phases. Consequently, based on the input current phases, the rotor position sensor accurately senses the position of the rotor 106. Further, sensing the accurate position of the rotor enables the offset control unit 112 to determine the rotor offset value and thereby initiating the auto-calibration of the rotor position sensor 110.
In an embodiment, the at least one offset control unit 112 is configured to receive sensed positions of the rotor 106. The offset control unit 112 utilizes the sensed rotor positions to minimize any deviations or inaccuracies in position data, and thereby, ensuring precise rotor positioning. Subsequently, minimized deviations improve the motor performance by aligning the control unit’s operations with the precise position of the rotor 106, resulting in better torque and efficiency of the motor 102. Hence, improving performance of the vehicle.
In an embodiment, the at least one offset control unit 112 is configured to determine rotor offset value based on received rotor positions. The offset control unit 112 computes the deviation or offset in rotor positioning, resulting in precise alignment of the rotor position sensor 110 (via calibration) with respect to the longitudinal axis of the rotor 106. Further, computing the deviation enables the offset control unit 112 to determine the phase lag between the phases of the input current, resulting in improved motor efficiency.
In an embodiment, the at least one offset control unit 112 is configured to compare the determined rotor offset value with predefined rotor positions, to initiate the auto-calibration of the at least one rotor position sensor 110. Comparing the determined rotor offset with predefined rotor positions enables the offset control unit 112 to accurately identify the variation (rotor offset) and align the rotor position sensor 110 (via calibration) with respect to the longitudinal axis of the rotor 106. Further, the auto-calibration ensures that the rotor position sensor 110 operates within a defined range of positions, and thereby reducing the margin of error in positioning and control of rotor 106.
In an exemplary embodiment, the stator 104 comprises three stator windings 114 (namely, R, Y,B) and two current sensors 108A,108B. The current sensors 108A,108B are connected to any two windings (R, Y or Y, B or B, R) of the three stator windings 114 (R, Y, B). The input current is supplied via inverters (a, b, c) to three stator windings 114 and the output current is measured via two current sensors 108A, 108B. Further, the input currents supplied via inverters have an orthogonal (90-degree) phase difference with each other. Further, the three stator windings 114 (R, Y, B) are arranged 120 degrees apart from each other. The current multiplier (M) is computed for a number of current inputs with varying phases (having orthogonal relationship with each other). For instance, in a first case the current input is provided via inverter “a” (in-phase) at stator winding “R” and return current flow is measured at inverter “b” (90 degrees out of phase) at stator winding “B”. Further, the current sensor 108A is connected at stator winding “R” and the current sensor 108B is connected at stator winding “B”. Based on the reading of sensor 108B, the current offset value V1 is computed for the first case. In a second case, the current input is provided via inverter “b” (in-phase) at stator winding “B” and return current flow is measured at inverter “c” (90 degrees out of phase) at stator winding “Y”. Further, the current sensor 108A is connected at stator winding “B” and the current sensor 108B is connected at stator winding “Y”. Based on the reading of sensor 108B, the current offset value V2 is computed for the second case. In a third case, the current input is provided via inverter “c” (in-phase) at stator winding “Y” and return current flow is measured at inverter “a” (90 degrees out of phase) at stator winding “R”. Further, the current sensor 108A is connected at stator winding “Y” and the current sensor 108B is connected at stator winding “R”. Based on the reading of sensor 108B, the current offset value V3 is computed for the third case. Furthermore, based on the computed offset values of the first, second and third case, the offset control unit 112 computes the multiplier value (M) which is mean of the V1, V2, and V3.
In another exemplary embodiment, the stator 104 comprises three stator windings 114 (namely, R, Y, B). The rotor position sensor 110 is connected to the rotor 106 and configured to sense positions of the rotor 106 based on the phase angle of the input current. The input current is supplied via inverters (a, b, c) to three stator windings 114. Further, the input currents supplied via inverters have an orthogonal (90-degree) phase difference with each other. Further, the three stator windings (R, Y, B) are arranged 120 degrees apart from each other. The rotor offset value (T) is computed for a number of current inputs with varying phases (having orthogonal relationships with each other). For instance, in case (1) the current input is provided via inverter “a” (in-phase) at stator winding “R” and return current flow is measured at inverter “b” (90 degrees out of phase) at stator winding “B”. Based on the reading of rotor position sensor 110, the position (T1) of the rotor is computed for case (1). In case (2) the current input is provided via inverter “b” (in-phase) at stator winding “B” and return current flow is measured at inverter “c” (90 degrees out of phase) at stator winding “Y”. Based on the reading of rotor position sensor 110, the position (T2) of the rotor is computed for case (2). In case (3) the current input is provided via inverter “c” (in-phase) at stator winding “Y” and return current flow is measured at inverter “a” (90 degrees out of phase) at stator winding “R”. Based on the reading of rotor position sensor 110, the position (T3) of the rotor is computed for case (3). Furthermore, based on the computed rotor position values of case (1), case (2), and case (3), the offset control unit computes rotor offset value (T) (mean of T1, T2, and T3).
In accordance with a second aspect, there is described method 200 of auto-calibration of a battery powered vehicle, the method 200 comprises:
- sensing current values flowing through at least one pair of windings of a stator of at least one motor, via a plurality of current sensors 108A, 108B;
- determining offset current values for the at least one pair of windings, via at least one offset control unit 112;
- determining a current multiplier value based on the determined offset current values, via the at least one offset control unit 112;
- determining rotor offset value for a rotor of the at least one motor 102, via the at least one offset control unit 112; and
- initiating auto-calibration of the plurality of current sensors 108A, 108B and/or of at least one rotor position sensor 110.
Figure 2 describes a method of auto-calibration of a battery powered vehicle. The method 200 starts at a step 202. At the step 202, the method comprises sensing current values flowing through at least one pair of windings of a stator of at least one motor 102, via a plurality of current sensors 108A, 108B. At a step 204, the method comprises determining offset current values for the at least one pair of windings, via at least one offset control unit 112. At a step 206, the method comprises determining a current multiplier value based on the determined offset current values, via the at least one offset control unit (such as the offset control unit 112 of Fig. 1). At a step 208, the method comprises determining rotor offset value for a rotor of the at least one motor, via the at least one offset control unit 112. At a step 210, the method comprises initiating auto-calibration of the plurality of current sensors 108A, 108B and/or of at least one rotor position sensor 110. The method 200 ends at the step 210.
In an embodiment, the method 200 comprises sensing current values flowing through the at least one pair of windings, by a plurality of current sensors 108A, 108B.
In an embodiment, the method 200 comprises receiving the sensed current values, to at least one offset control unit 112.
In an embodiment, the method 200 comprises comparing the received current values with input current values, by the at least one offset control unit 112.
In an embodiment, the method 200 comprises determining a current multiplier value based on the determined offset current values, by the at least one offset control unit 112.
In an embodiment, the method 200 comprises initiating the auto-calibration of the plurality of current sensors, based on the determined current multiplier value, by the at least one offset control unit 112.
In an embodiment, the method 200 comprises sensing positions of the rotor based on the current values flowing through the at least one pair of windings, by the at least one rotor position sensor 110.
In an embodiment, the method 200 comprises receiving sensed positions of the rotor, to the at least one offset control unit 112.
In an embodiment, the method 200 comprises determining rotor offset value based on received rotor positions, by the at least one offset control unit 112.
In an embodiment, the method 200 comprises comparing the determined rotor offset value with predefined rotor positions, and initiating the auto-calibration of the at least one rotor position sensor 110 by the at least one offset control unit 112.
In an embodiment, the method 200 comprises sensing current values flowing through the at least one pair of windings, by a plurality of current sensors 108A, 108B. Furthermore, the method 200 comprises receiving the sensed current values, to at least one offset control unit 112. Furthermore, the method 200 comprises comparing the received current values with input current values, by the at least one offset control unit 112. Furthermore, the method 200 comprises determining a current multiplier value based on the determined offset current values, by the at least one offset control unit 112. Furthermore, the method 200 comprises initiating the auto-calibration of the plurality of current sensors, based on the determined current multiplier value, by the at least one offset control unit 112. Furthermore, the method 200 comprises sensing positions of the rotor 106 based on the current values flowing through the at least one pair of windings, by the at least one rotor position sensor 110. Furthermore, the method 200 comprises receiving sensed positions of the rotor 106, to the at least one offset control unit 112. Furthermore, the method 200 comprises determining rotor offset value based on received rotor positions, by the at least one offset control unit 112. Furthermore, the method 200 comprises comparing the determined rotor offset value with predefined rotor positions, and initiating the auto-calibration of the at least one rotor position sensor 110 by the at least one offset control unit 112.
In an embodiment, the method 200 comprises sensing current values flowing through at least one pair of windings of a stator of at least one motor 102, via a plurality of current sensors 108A, 108B. Furthermore, the method 200 comprises determining offset current values for the at least one pair of windings, via at least one offset control unit 112. Furthermore, the method 200 comprises determining a current multiplier value based on the determined offset current values, via the at least one offset control unit 112. Furthermore, the method 200 comprises determining the rotor offset value for a rotor of the at least one motor 102, via the at least one offset control unit 112. Furthermore, the method 200 comprises initiating auto-calibration of the plurality of current sensors 108A, 108B and/or of at least one rotor position sensor 110.
Based on the above-mentioned embodiments, the present disclosure provides significant advantages such as, (but not limited to) improved precision and accuracy for the auto-calibration, accurately determining the current and rotor offset, and thereby, precisely aligning the rotor(s) in accordance with the operational parameters.
It would be appreciated that all the explanations and embodiments of the system 100 also apply mutatis-mutandis to the method 200.
In the description of the present invention, it is also to be noted that, unless otherwise explicitly specified or limited, the terms “disposed,” “mounted,” and “connected” are to be construed broadly, and may for example be fixedly connected, detachably connected, or integrally connected, either mechanically or electrically. They may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Modifications to embodiments and combinations of different embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, and “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural where appropriate.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the present disclosure, the drawings, and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
,CLAIMS:WE CLAIM:
1. A system (100) for auto-calibration of a battery powered vehicle, the system comprising:
- at least one poly-phase motor (102) comprising a stator (104) and a rotor (106);
- a plurality of current sensors (108A, 108B);
- at least one rotor position sensor (110); and
- at least one offset control unit (112),
wherein the stator (104) comprises a plurality of stator windings and the plurality of current sensors (108) are connected to at least one pair of windings of the plurality of stator windings.
2. The system (100) as claimed in claim 1, wherein the plurality of current sensors (108) are configured to sense current values flowing through the at least one pair of windings.

3. The system (100) as claimed in claim 1, wherein the at least one offset control unit (112) is configured to receive the sensed current values.

4. The system (100) as claimed in claim 1, wherein the at least one offset control unit (112) is configured to compare the received current values with input current values, to determine offset current values for the at least one pair of windings.

5. The system (100) as claimed in claim 1, wherein the at least one offset control unit (112) is configured to determine a current multiplier value based on the determined offset current values.

6. The system (100) as claimed in claim 1, wherein the at least one offset control unit (112) is configured to initiate the auto-calibration of the plurality of current sensors (100), based on the determined current multiplier value.

7. The system (100) as claimed in claim 1, wherein the at least one rotor position sensor (110) is configured to sense positions of the rotor (104) based on the phase angle of the input current values flowing through the at least one pair of windings.

8. The system (100) as claimed in claim 1, wherein the at least one offset control unit (112) is configured to receive sensed positions of the rotor (104).

9. The system (100) as claimed in claim 1, wherein the at least one offset control unit (112) is configured to determine rotor offset value based on received rotor positions.

10. The system (100) as claimed in claim 1, wherein the at least one offset control unit (112 is configured to compare the determined rotor offset value with predefined rotor positions, to initiate the auto-calibration of the at least one rotor position sensor (110).

11. A method (200) of auto-calibration of a battery powered vehicle, the method (200) comprises:
- sensing current values flowing through at least one pair of windings of a stator of at least one motor (102), via a plurality of current sensors (108);
- determining offset current values for the at least one pair of windings, via at least one offset control unit (112);
- determining a current multiplier value based on the determined offset current values, via the at least one offset control unit (112);
- determining rotor offset value for a rotor of the at least one motor (102), via the at least one offset control unit (112); and
- initiating auto-calibration of the plurality of current sensors (100) and/or of at least one rotor position sensor (112).