Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to Electric Vehicles (EVs) and Hybrid Vehicles (HVs). Particularly, the present disclosure relates to a method of optimizing control strategy for a motor and a Motor Control Unit (MCU) for EVs and HVs.
BACKGROUND
[0002] Increase in air pollution and constant reducing of fossil fuels is increasing the demand of Electric Vehicles (EVs) and Hybrid Vehicles (HVs). The conventional motor control systems and strategies used within the EVs and/or HVs do not consistently ensure that the torque requested by a driver operating the vehicle is accurately provided by the vehicle's electric motor. In conventional EVs and HVs, static Proportional Integral (PI) gains are used in control algorithms, whose value cannot be changed according to variations in motor parameters. Moreover, the conventional control algorithms use look-up tables of current vs voltage values for current sensing. As a result, for each current measurement, the conventional control algorithms perform a two-level transition, which includes a first transition from Analog-to-Digital Convertor (ADC) count to voltage value, and then a second transition from voltage value to the current value. The two-level transition is error-prone, requires more processing, as well as takes considerable time to return the sensed current value.
[0003] Thus, the conventional control algorithms cause the current sensing to be less precise and an error of conversion cycle is carried forward. Also, over a period of time, the motor parameters are subject to change, and the static gains cannot provide much stability to the motor. Consequently, the use of static gains in control strategy leads to reduction in e-drive performance over a period of time. Also, an improper tuning will lead to performance loss, higher transients to small perturbations and reduced power train efficiency.
[0004] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY
[0005] Disclosed herein is a method of optimizing control strategy for a motor. The method comprises sensing, using a Motor Control Unit (MCU) associated with a motor, real-time values of a plurality of current signals being supplied to a current sensor associated with the MCU. Further, the method comprises a normalized value by multiplexing the real-time values of each of the plurality of current signals and real-time output values from the current sensor. Thereafter, the method comprises determining a supply current value based on a reference Analog to Digital Convertor (ADC) count corresponding to the normalized value. Finally, the method comprises controlling the motor in real-time based on the supply current value.
[0006] Further, the present disclosure relates to a Motor Control Unit (MCU). The MCU system comprises a sensor supply, a signal conditioning unit, a multiplexer and a Digital Signal Processor (DSP). The sensor supply supplies a plurality of current signals to a current sensor. Further, the signal conditioning unit senses real-time values of the plurality of current signals. Furthermore, the multiplexer is configured for multiplexing the real-time values of each of the plurality of current signals and real-time output values from the current sensor for generating a normalized value. Finally, the Digital Signal Processor (DSP) determines a supply current value based on an Analog to Digital Convertor (ADC) count corresponding to the normalized value.
[0007] 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 THE ACCOMPANYING DRAWINGS
[0008] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and regarding the accompanying figures, in which:
[0009] FIG. 1 (Prior Art) shows an overview of functioning of an existing/conventional Motor Control Unit (MCU).
[0010] FIG. 2 shows an overview of functioning of the proposed Motor Control Unit (MCU) in accordance with some embodiments of the present disclosure.
[0011] FIG. 3 shows a detailed block diagram of the proposed Motor Control Unit (MCU), in accordance with some embodiments of the present disclosure.
[0012] FIG. 4 shows a flowchart illustrating a method of optimizing control strategy for a motor, in accordance with some embodiments of the present disclosure.
[0013] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether such computer or processor is explicitly shown.
DETAILED DESCRIPTION
[0014] In the present document, the word “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.
[0015] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the specific forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
[0016] The terms “comprises”, “comprising”, “includes”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device, or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
[0017] Fig. 1 shows an overview of the conventional Motor Control Unit (MCU) used in an electrical vehicle and/or a hybrid vehicle. In the conventional MCU, the supply current value to be supplied to the motor is determined using the static values of power supply and zero current reference. The signal conditioning unit receives the sensor out and reference out from the current sensor. The sensor out value from the current sensor is a current value determined based on a positive current sensor supply and a negative current sensor supply. The reference out value is a voltage value used to specify a direction of motion of the vehicle. In other words, the signal conditioning unit does not receive the live values from the sensor supply. For current sensing, look up tables of current vs voltage and static values of power supply and zero current reference are used. Also, the current measurement involves a two-level conversion including a conversion from Analog to Digital Convertor (ADC) count to voltage conversion and a conversion from voltage to current values.
[0018] In view of the aforesaid limitations in the conventional MCUs, the present disclosure aims to provide an optimized control strategy for a motor and a Motor Control Unit (MCU). In an embodiment, the motor is at least one of an Electric Vehicle (EV) motor or a Hybrid Vehicle (HV) motor. In an embodiment, the proposed MCU senses real-time values of a plurality of current signals being supplied to a current sensor associated with the MCU. Further a normalized value of the current signals is generated by multiplexing the real-time values of each of the plurality of current signals and real-time output values from the current sensor. Further, the MCU determines a supply current value based on a reference Analog to Digital Convertor (ADC) count corresponding to the normalized value. Finally, the MCU controls the motor in real-time based on the supply current value.
[0019] In other words, the proposed disclosure aims to optimize the control strategy for the motor by using the dynamic and/or live values of the current signals and simplifying the conversion of ADC count to current values. That is, the proposed disclosure uses a count based approach to improve accuracy while measuring the supply current value directly from the ADC count.
[0020] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in 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.
[0021] FIG. 2 shows an overview of functioning of a Motor Control Unit (MCU) in accordance with some embodiments of the present disclosure.
[0022] In an embodiment, a vehicle may be configured with a Motor Control Unit 201 (MCU) and the MCU 201 may be configured for optimizing control strategy for a motor of the vehicle. In an embodiment, the motor may be at least one of an Electric Vehicle (EV) and/or a Hybrid Vehicle (HV). As an example, the vehicle may be a passenger vehicle such as a car, a van, a bus and/or a commercial vehicle such as pick-up trucks. In an embodiment, the MCU 201 may include, without limiting to, a sensor supply 203, a signal conditioning unit 211, a multiplexer 217 and a Digital Signal Processor 221 (DSP). In an embodiment, the MCU 201 may be a computing unit dedicated for optimizing control strategy for a motor in the vehicle. In an embodiment, an existing MCU 201 of the vehicles may be upgraded to perform functionalities, in accordance with the embodiments of the present disclosure.
[0023] In an embodiment, the signal conditioning unit 211 may be configured to sense the real-time and/or live values of a plurality of current signals 209 being supplied to a current sensor 205. The current sensor 205 may be associated with the MCU 201. In an embodiment, the plurality of current signals 207 may be updated continuously based on the requirement of a driver of the vehicle. As an example, the driver of the vehicle may press the accelerator pedal demanding sudden increase in the speed of the vehicle, which would require the MCU to provide the required supply current value. In another example, the driver of the vehicle may press the brake pedal, reducing the speed of the vehicle, which would require the MCU to reduce the supply current value. This fluctuation in the demand current leads to continuous changes in the current signal values. In an embodiment, the signal conditioning unit 211 may also sense the real-time output values 213 from the current sensor 205. In an embodiment, the real-time output values 213 from the current sensor 205 comprises at least one of a sensor output current value and a reference voltage value of the current sensor 205. The sensor output current value is determined based on the plurality of current signals 207 received from the sensor supply 203. The reference voltage value may be used to specify a direction of motion of the vehicle. As an example, suppose the range of the reference voltage value is between 0 Volts (V) to 5 V. Here, when the vehicle is in an idle or still state, the reference voltage value may be 2.5V. Similarly, if the vehicle is in a forward motion, the reference voltage value may be more than 2.5V and if the vehicle is in a backward motion, the reference voltage value may be less than 2.5V. In an embodiment, the signal conditioning unit 211 performs manipulations and prepares the plurality of current signals 207 and the real-time output values 213 for further processing.
[0024] In an embodiment, after sensing the dynamic values of the plurality of current signals 209 and performing signal conditioning, the MCU 201 generates a normalized value 219 of the current signals by multiplexing the dynamic values 215. The dynamic values 215 may comprise real-time values of each of the plurality of current signals 209 and the real-time output values 213 received from the signal conditioning unit 211. In an embodiment, the multiplexer 217 is used to multiplex the dynamic values 215 and generate the normalized value 219. In an embodiment, the normalized value 219 is input to a single-pin Analog to Digital Convertor (ADC) channel on the DSP 221.
[0025] In an embodiment, upon receiving the normalized value 219, the DSP 221 determines a supply current value based on a reference ADC count corresponding to the normalized value 219. In an embodiment, the normalized value 219 is updated continuously as it depends on the dynamic values 215 of the current signals, and this, in turn, causes the ADC count value to be updated in accordance with the changes in the normalized value 219. As a result, the supply current value determined by the DSP 221 shall be more accurate as it corresponds to the live values of the current signals. In an embodiment, the supply current value indicates value of the current signal being supplied to the motor in response to a current demand corresponding to acceleration of the vehicle. Further, the supply current value is a value between -900A and +900A. In an embodiment, the DSP 221 determines the supply current value directly from the ADC count value. In an embodiment, the DSP 221 implements low pass filter on ADC count which avoids the noise in the ADC count. In an embodiment, degradation of the motor and/or depletion of the battery conditions may not affect the accuracy of the current sensing, since the MCU 201 determines the supply current value based on the dynamic values 215.
[0026] In an embodiment, after determining the supply current value, the MCU 201 controls the motor in real-time based on the supply current value. In an embodiment as per the requirement from the driver and/or the motor the current supply value changes dynamically. As an example, the driver of the vehicle may press the accelerator pedal demanding sudden increase in the speed of the vehicle, which would require the MCU 201 to provide the required supply current value. In another example, the driver of the vehicle may press the brake pedal, reducing the speed of the vehicle, which would require the MCU 201 to reduce the supply current value
[0027] In an embodiment, when the driver of the EV and/or the HV presses the accelerator pedal in the vehicle or decelerates, there is a sudden change in the torque demand and The sudden change in the torque demand should be met by the motor of the vehicle. In an embodiment, the motor should be supplied with the required supply current value as per the torque requirement. In an embodiment, the sensor supply 203 supplies the plurality of current signals 207 to the current sensor 205. At the same time, the signal conditioning unit 211 directly senses the live values of the plurality of current signals 209. Further, the signal conditioning unit 211 also receives the real-time output values 213 from the current sensor 205and sends the conditioned dynamic values 215 to the multiplexer 217 to generate a normalized value 219. The dynamic values 215 may comprise the real-time values of each of the plurality of current signals and real-time output values 213 from the current sensor 205. In an embodiment, the normalized value 219 is supplied to a single-pin ADC counter in the DSP 221. Further, the supply current value is determined based on a reference ADC count output by the ADC counter. The reference ADC count corresponds to the normalized value 219. Finally, the motor is supplied with the determined supply current value to meet the torque demand created by the driver.
[0028] FIG. 3 shows a detailed block diagram of a Motor Control Unit (MCU) 201, in accordance with some embodiments of the present disclosure.
[0029] In an embodiment, the MCU 201 may include an I/O Interface 301, a Digital Signal Processor (DSP) 221, a memory 303 storing data 305, a sensor supply 203, a signal conditioning unit 211, a multiplexer 217 and an Analog and Digital Convertor (ADC) counter 313. The I/O interface 301 may be coupled with the MCU 201 for receiving and transmitting an input signal or/and an output signal related to one or more operations of the MCU 201.
[0030] In an embodiment, the data 305 stored in the memory may include, without limitation, values of a plurality of current signals 209, real-time output values 213, a normalized value 219, a supply current value 309 and other data 311. In some implementations, the data 305 may be stored within the memory in the form of various data structures. Additionally, the data 305 may be organized using data models, such as relational or hierarchical data models. The other data 311 may include various temporary data and files generated by the different components of the MCU 201.
[0031] In an embodiment, the values of the plurality of current signals 209 are the live and/or dynamic values of current signals being supplied to a current sensor 205 associated with the MCU 201. In an embodiment, the signal conditioning unit 211 senses the values of the plurality of current signals 209.
[0032] In an embodiment, the real-time output values 213 comprise at least one of a sensor output current value and a reference voltage value of the current sensor 205. In an embodiment, the real-time output values 213 may be used to generate the normalized value 219.
[0033] In an embodiment, the normalized value 219 is the value generated by multiplexing the real-time values of each of the plurality of current signals 209 and real-time output values 213 received from the current sensor 205. In an embodiment, the normalized value 219 may be further used to determine the supply current value 309.
[0034] In an embodiment, the reference ADC count 307 is the count corresponding to the normalized value 219. In an embodiment, the reference ADC count 307 is used to determine the supply current value 309.
[0035] In an embodiment, the supply current value 309 indicates value of the current signal being supplied to the motor in response to a current demand corresponding to acceleration of the vehicle. In an embodiment, the supply current value 309 may be a value between -900A and +900A.
[0036] In an embodiment, the data 305 may be processed by the different components of the MCU 201. In some implementations, the different components may be communicatively coupled to the Digital Signal Processor 221 for performing one or more functions of the MCU 201. In an implementation, the different components may include, without limiting to, a sensor supply 203, a signal conditioning unit 211, a multiplexer 217 and an Analog to Digital Convertor (ADC) counter 221.
[0037] In an embodiment, the sensor supply 203 may be configured for supplying a plurality of current signals 207 to a current sensor 205. In an embodiment, the signal conditioning unit 211 may be configured for sensing real-time values of the plurality of current signals 209 and perform signal conditioning on the real-time values of the plurality of current signals 209 and the real-time output values 213 received from the current sensor 205. Further, the signal conditioning unit 211 may be configured to provide the dynamic values 215 to the multiplexer 217. In an embodiment, the multiplexer 217 may be configured for multiplexing the real-time values of each of the plurality of current signals 209 and real-time output values 213 from the current sensor 205 for generating a normalized value 219. In an embodiment, the ADC counter 313 may be configured for converting the analog current signals to corresponding digital values and determine a total count of the signals. In an embodiment, the DSP 221 may be configured for determining a supply current value 309 based on the ADC count 307 corresponding to the normalized value 219.
[0038] FIG. 4 shows a flowchart illustrating a method of optimizing control strategy for a motor, in accordance with some embodiments of the present disclosure.
[0039] As illustrated in FIG. 4, the method 400 may include one or more blocks illustrating a method of optimizing control strategy for a motor. The method 400 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform specific functions or implement specific abstract data types.
[0040] The order in which the method 400 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof.
[0041] At block 401, the method 400 includes sensing, by a Motor Control Unit (MCU) 201 associated with a motor, real-time values of a plurality of current signals 207 being supplied to a current sensor 205 associated with the MCU 201. In an embodiment, the motor is at least one of an Electric Vehicle (EV) motor and/or a Hybrid Vehicle (HV) motor.
[0042] At block 403, the method 400 includes generating, by the MCU 201, a normalized value 219 by multiplexing the real-time values of each of the plurality of current signals 207 and real-time output values 213 from the current sensor 205. In an embodiment, the real-time output values 213 from the current sensor 205 comprises at least one of a sensor output current value and a reference voltage value of the current sensor 205.
[0043] At block 405, the method 400 includes determining, by the MCU 201, a supply current value 309 based on a reference Analog to Digital Convertor (ADC) count 307 corresponding to the normalized value 219. In an embodiment, the supply current value 309 indicates value of the current signal being supplied to the motor in response to a current demand corresponding to acceleration of the vehicle.
[0044] At block 407, the method 400 includes controlling, by the MCU 201, the motor in real-time based on the supply current value 309. In an embodiment, the supply current value 309 is a value between -900A and +900A. In an embodiment, the supply current value 309 updates dynamically based on the current demand.
[0045] Advantages of the embodiments of the present disclosure are illustrated herein.
[0046] In an embodiment, the present disclosure reduces the precision loss in calculation of the supply current value. This helps in improving the current loop stability.
[0047] In an embodiment, the present disclosure performs accurate current sensing and utilizes dynamic Proportional Integral (PI) gain. This helps in increasing the stability of the motor control algorithm.
[0048] In an embodiment, the present disclosure provides smooth transitions during sudden torque demand by accurately sensing the supply current values required to meet the torque demands of the motor.
[0049] In an embodiment, the present disclosure uses dynamic values of the plurality of current signals instead of hard coded values. This helps in increasing the accuracy in determining supply current values and eliminates the error.
[0050] In an embodiment, the present disclosure determines supply current value directly from the Analog to Digital Convertor (ADC) count value. This reduces the number of conversion steps and eliminates the possible errors occurring in each stage of the conversion.
[0051] In light of the technical advancements provided by the disclosed method and the Motor Control Unit (MCU), the claimed steps, as discussed above, are not routine, conventional, or well-known aspects in the art, as the claimed steps provide the aforesaid solutions to the technical problems existing in the conventional technologies. Further, the claimed steps clearly bring an improvement in the functioning of the system itself, as the claimed steps provide a technical solution to a technical problem.
[0052] The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the embodiments", "one or more embodiments", "some embodiments", and "one embodiment" mean "one or more (but not all) embodiments of the invention(s)" unless expressly specified otherwise.
[0053] The terms "including", "comprising", “having” and variations thereof mean "including but not limited to", unless expressly specified otherwise.
[0054] The enumerated listing of items does not imply that any or all the items are mutually exclusive, unless expressly specified otherwise. The terms "a", "an" and "the" mean "one or more", unless expressly specified otherwise.
[0055] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.
[0056] When a single device or article is described herein, it will be clear that more than one device/article (whether they cooperate) may be used in place of a single device/article. Similarly, where more than one device/article is described herein (whether they cooperate), it will be clear that a single device/article may be used in place of the more than one device/article or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of invention need not include the device itself.
[0057] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
[0058] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Referral Numerals:
Reference Number Description
201 Motor Control Unit (MCU)
203 Sensor supply
205 Current sensor
207 Current signals
209 Values of current signals
211 Signal conditioning unit
213 Output values
215 Dynamic values
217 Multiplexer
219 Normalized value
221 Digital Signal Processor (DSP)
301 I/O Interface
303 Memory
305 Data
307 Reference ADC count
309 Supply current value
311 Other data
313 Analog to Digital Convertor (ADC) counter
, Claims:WE CLAIM:
1. A method of optimizing control strategy for a motor, the method comprising:
sensing, by a Motor Control Unit (MCU) associated with the motor, real-time values of a plurality of current signals being supplied to a current sensor associated with the MCU;
generating, by the MCU, a normalized value by multiplexing the real-time values of each of the plurality of current signals and real-time output values from the current sensor;
determining, by the MCU, a supply current value based on a reference Analog to Digital Convertor (ADC) count corresponding to the normalized value; and
controlling, by the MCU, the motor in real-time based on the supply current value.

2. The method as claimed claim 1, wherein the motor is at least one of an Electric Vehicle (EV) motor or a Hybrid Vehicle (HV) motor.

3. The method as claimed in claim 1, wherein the real-time output values from the current sensor comprises at least one of a sensor output current value and a reference voltage value of the current sensor.

4. The method as claimed in claim 1, wherein the supply current value indicates value of the current signal being supplied to the motor in response to a current demand corresponding to acceleration of the vehicle.

5. The method as claimed in claim 1, wherein the supply current value is a value between -900A and +900A.

6. A Motor Control Unit (MCU) for a vehicle, the MCU comprising:
a sensor supply for supplying a plurality of current signals to a current sensor;
a signal conditioning unit for sensing real-time values of the plurality of current signals;
a multiplexer for multiplexing the real-time values of each of the plurality of current signals and real-time output values from the current sensor for generating a normalized value; and
a Digital Signal Processor (DSP) for determining a supply current value based on an Analog to Digital Convertor (ADC) count corresponding to the normalized value.

7. The MCU as claimed claim 6, wherein the MCU is configured to control a motor of the vehicle in real-time based on the supply current value, wherein the motor is at least one of an Electric Vehicle (EV) motor or a Hybrid Vehicle (HV) motor.

8. The MCU as claimed in claim 6, wherein the real-time output values from the current sensor comprises at least one of a sensor output current value and a reference voltage value of the current sensor.

9. The MCU as claimed in claim 6, wherein the supply current value indicates value of the current signal being supplied to the motor in response to a current demand corresponding to acceleration of the vehicle.

10. The MCU as claimed in claim 6, wherein the supply current value is a value between -900A and +900A.