1.A power assist system for reducing load power of a primary energy source (102) in an electric or a hybrid electric vehicle, said power assist system comprising:
a primary energy source (102) that is electrically connected with an electric motor (114) of the electric or hybrid electric vehicle, wherein the primary energy source (102) provides electrical energy to run the electric motor (114);
a high power density device (104) that is electrically connected with the electric motor (114);
a vehicle monitoring unit (106) that determines a load power of the electric motor (114) based on one or more vehicle parameters and one or more path parameters, wherein the one or more vehicle parameter comprises at least one of a level of energy in the primary energy source (102) or a level of energy in the high power density device (104) or rate of acceleration, wherein the one or more path parameter comprise at least one of (a) an inclined or a slope position at which the vehicle is running or (b) potholes in a path at which the vehicle is running, wherein the vehicle monitoring unit (106) communicates information associated with the load power of the electric motor (114) to a power management system 100;
a switching unit (108) that is communicatively connected to the vehicle monitoring unit (106) and activates the high power density device (104) to provide additional electrical power to the electric motor (114) to reduce the load power of the primary energy source (102) when the load power of the electric motor (114) exceeds the first threshold level; a level detector (110) that is connected with the primary energy source (102) and the high power density device (104), wherein the level detector (110) determines a level of electrical energy remaining in the primary energy source (102) based on (i) at least one of a charge level, a voltage, internal resistance, a temperature of the primary energy source (102), wherein the level detector (110) determines a level of electrical energy remaining in the high power density device (104) based on the conduction ratio between the electric motor (114) to the high power density device (104) and the conduction ratio between the electric motor (114) and the primary energy source (102), wherein the level detector (110) communicates, to the power management system (100) through the vehicle monitoring unit (106), the level of electrical energy remaining in the primary energy source (102) and the high power density device (104);
a regenerative coupling unit (116) that is connected with the high power density device (104) to provide regenerative electrical energy that is obtained from the electric motor (114) to the high power density device (104) from the electric motor (114) when the vehicle is in non-drive condition; and
a limiter circuit (112) that is communicatively connected to the level detector (110), wherein the power management system (100) receives the level of electrical energy remaining in at least one of the primary energy source (102) or the high power density device (104) from the level detector (110), wherein the limiter circuit (112) is activated to provide the electrical energy to the high power density device (104) from the primary energy source (102) when the level of electrical energy of the high power density device (104) is below the second threshold level using the power management system (100),
wherein, the switching unit (108) activates the high power density device (104) to provide additional electrical power to the electric motor (114) to reduce the load power of (102) when the load power of the electric motor (114) exceeds the first threshold level.

2. The system as claimed in claim 1, wherein the high power density device (104) is selected from any one of a super capacitor, a hybrid capacitor, a gold capacitor or a double layer capacitor with a value of ranges from 10 F to 20000F, also the high power density device (104) may selected from any one of a high power composite lithium based batteries, lithium based capacitors that comprise at least one of a Lithium Titanate (LTO) or lithium compositions, wherein a high power lithium and titanium based batteries comprises high power density cells.

3. The system as claimed in claim 1, wherein the vehicle monitor unit (106) comprises
a first microcontroller that processes and communicates the information associated to the load power of the electric motor (114) which is determined based on the one or more vehicle parameters and the one or more path parameters;
a plurality of sensors that measures a signal associated with each of the one or more vehicle parameters and the one or more path parameters.


4. The system as claimed in claim 1, wherein the limiter circuit (112) comprises a unidirectional semiconductor device (302) and a controlled unidirectional semiconductor switch (304), wherein the unidirectional semiconductor device (302) and the controlled unidirectional semiconductor switch (304) comprises at least one of (a) a fast recovery diode, (b) a thyristor or (c) a power transistor.

5. The system as claimed in claim 1, wherein switching unit (108) comprises:
high speed unidirectional switching components (202A-B) that are arranged in parallel manner, wherein the high speed unidirectional switching components (202A-B) activates the high power density device (104) to supply the additional electrical power to the electric motor (114) in less than a second in a single sample period when the load power of the electric motor (114) exceeds the first threshold level, wherein the high speed unidirectional switching components (202A-C) comprises at least one of (i) a metal oxide semiconductor field effect transistor, (ii) a insulated-gate bipolar transistor, (iii) a fast recovery diode or (iv) a second PN diode;
a second microcontroller is in the power management system 100, that receives the information associated with the load of the vehicle from the first microcontroller, wherein the second microcontroller also receives the level of electrical energy remaining in at least one of the primary energy source (102) or the high power density device (104) from the level detector (110), wherein the second microcontroller calculates the load power of the primary source (102) to control the high speed unidirectional switching components (202A-B) for providing the electrical energy to the electric motor (114);
wherein, the second microcontroller activates the high power density device (104) of the power management system (100) to supply the additional electrical power to the electric motor (114) using the high speed unidirectional switching components (202A-C) based on the information associated the load of the vehicle and the level of electrical energy remaining in at least one of the primary energy source (102) or the high power density device (104) received from the level detector (110).

a buffer capacitor (204) that controls a supply of the electrical energy to the electric motor (114) from the primary energy source (102) and the high power density device (104), wherein the buffer capacitor (204) comprises an electrolytic capacitor;
an inductor coil (206) that aids in reduction of ripples in the electrical power that is supplied to the electric motor (114), wherein the inductor coil (206) also boosts the voltage of the high power density device (104), wherein a value of the inductor coil (206) ranges from10 µH to 100 mH and a value of internal resistance of the inductor coil (206) ranges from 1m? to 1?; and
a freewheeling diode (208) that prevents damage to the power management system 100 and other electrical circuits of the power assist system which can be caused by back electro-magnetic force produced by the inductor coil (206).


6. The system as claimed in claim 1, wherein the conduction ratio between the primary energy source (102) to the electric motor (114) and the high power density device (104) to the electric motor (114) is determined based on charge level, effective voltage level, the internal resistance and temperature along with at least one of back Electro Motive Force (EMF) of the electric motor (114), one or more vehicle parameters or one or more path parameters.

7. A method of reducing a load power of a primary energy source (102) of an electric and a hybrid electric vehicle, comprising:
determining, using a vehicle monitoring unit (106), a load power of the electric motor (114) which is directly proportional to the load power of the primary energy source (102) based on one or more vehicle parameters and one or more path parameter, wherein, the vehicle monitoring unit (106) communicates information associated with the load power of the primary energy source (102) to a power management system (100);
receiving, using a switching unit (108), the information associated with the load power of the primary energy source (102);
receiving, using a level detector (110), the level of electrical energy remaining in at least one of the primary energy source (102) or the high power density device (104);
determining, using the power management system (100), whether the load power of the primary energy source (102) is exceeds a first threshold level;
providing, using high power density device (104), additional electrical power to the electric motor (114) when the load power of the primary energy source (102) is exceeds the first threshold level; and
providing, using a regenerative coupling unit (117), regenerative electrical energy to the high power density device (104) from the electric motor (114) when the vehicle is in non-drive condition.

8. The method as claimed in claim 7, wherein the method comprising
determining, using a level detector (110), a level of electrical energy remaining in at least one of (a) primary energy source (102) based on (i) at least one of a charge level, a voltage, internal resistance or a temperature of the primary energy source (102), wherein the level detector (110) determines a level of electrical energy remaining in the high power density device (104) based on conduction ratio between the electric motor (114) and the high power density device (104) and the primary energy source (102); and
communicating, using the level detector (110), the level of electrical energy remaining in the primary energy source (102) and the high power density device (104) to the power management system (100).


9. The method as claimed in claim 7, wherein the method comprising
receiving, using a level detector (110), the level of electrical energy remaining based on the following charge level, voltage, internal resistance and a temperature in the primary energy source (102) and the high power density device (104) is also based on the conduction ratio between the high power density device (104) and the electric motor (114); and
providing, using a limiter circuit (112), an electrical energy from the primary energy source (102) to the high power density device (104) when the level of electrical energy of the high power density device (104) is below the second threshold level.
, Description:BACKGROUND
Technical Field
[0001] The embodiments herein generally relates to vehicular power assist system, and more particularly, to the system and method for managing the power demand of the vehicle, based on the load conditions.
Description of the Related Art
[0002] Mileage of vehicles is one of the important factors analyzed by the user during the purchase of the vehicle as it directly affects the cost of maintaining the vehicle. The conventional fuel cost keeps varying in real time, and there is no assurance that the fuel price will be stable in future. It is not a sustainable energy source for future due to environmental as well as pricing issues. The users are looking for an alternative solution to these problems for some time. The electrical vehicles and the hybrid vehicles are the attractive alternate solutions. The electrical vehicle operates on the electric power. While the hybrid vehicle uses both the conventional fuel source and the electrical source to operate the vehicle. This technique improves the mileage of the vehicle considerably. The mileage of vehicles is one of the important factors considered by a user while purchasing a vehicle. The fuel cost is randomly varies in time, and there is no consistency or predictability in the prices of the fuel. The users are looking for an alternative solution because of the issue of the fluctuations of fuel price and mileage of the vehicle. Now a day the hybrid vehicles and the electric vehicles are an attractive and alternative solution to the users. The hybrid vehicle uses both the fuel source and the electrical source to operate the vehicle. This technique improves the mileage of the vehicle. The electrical vehicle operates with the electric power. Both hybrid electric vehicles and the electric vehicles use a power management system to handle the electric power consumption of the vehicles. Due to poor energy or power capacity, traffic condition, poor energy harvesting during braking or mechanical errors will affect the mileage and performance of the vehicle are at stake. Therefore, at the beginning of the acceleration is where more power is consumed and energy loss occurs during the deceleration. This scenario is termed as the increased power demand or load.
[0003] In one of the earlier approaches, the primary battery is used as a high energy density device along with a high power density device. The high power density device can be but not only limited to an ultra-capacitor and or can be lithium based cells which are high power density devices. The power consumed from the high energy density device and the high power density device is controlled via a control switch which activates at different time intervals. Here the power consumed is at fixed intervals and at different samples for high power density device and primary energy source. This approach may not detect the exact power demand of the load in real time. In most cases, the high power density device is not able to produce enough power to run the motor because of low charge in it. The approach to reduce the current rate of the main electric energy source or primary battery will increase the battery life time as well as mileage. But this is not effective due to the factors like different energy level, internal resistance, temperature and state of charge level. A hybrid electric energy source for an electric vehicle or hybrid electric vehicle may be implemented by connecting a high power density device across the main electric energy source permanently. This approach is also not efficient because of the unexpected discharge from the main energy source and high power density device or ultra-capacitor due to the different charge level and internal resistance.
[0004] Accordingly, there remains a need for a system and method for managing the power demand of the vehicle based on the different load conditions and also to recover the braking energy effectively by regenerative braking.

SUMMARY
[0005] The objective of the present invention is to manage the power demand of the vehicle based on the load conditions and also to recover the braking energy effectively by regenerative braking.
[0006] In an aspect, a power assist system includes a primary energy source, a high power density device, a vehicle monitoring unit, a switching unit, a regenerative coupling unit, a level detector, power management system, electric motor and a limiter circuit. The primary energy source that is electrically connected with an electric motor of the electric and hybrid electric vehicle. The primary energy source provides electrical energy to run the electric motor. The high power density device that is electrically connected with the electric motor. The vehicle monitoring unit that determines a load power of the electric motor based on one or more vehicle parameters and one or more path parameters. The one or more vehicle parameter includes at least one of a level of energy in the primary energy source or a level of energy in the high power density device. The path parameter includes at least one of (a) an inclined or a slope position at which the electric and hybrid electric vehicle is running or (b) potholes in a path at which the vehicle is running. The vehicle monitoring unit communicates information associated with the load power of the electric motor with the power management system.
[0007] The switching unit that is communicatively connected to the vehicle monitoring unit and activates the high power density device to provide additional electrical power to the electric motor to reduce the load power of the primary energy source when the load power of the electric motor exceeds the first threshold level. The level detector that is connected with the primary energy source and the high power density device. The level detector determines a level of electrical energy remaining in the primary energy source based on (i) at least one of a charge level, a voltage, internal resistance, a temperature of the primary energy source. The level detector determines a level of electrical energy remaining in the high power density device based on the voltage levels of the high power density device and the conduction ratio between the electric motor to the high power density device also or to the primary energy source. The level detector communicates the level of electrical energy remaining in the primary energy source and the high power density device with the vehicle monitoring unit. The regenerative coupling unit that is electrically connected to the high power density device which stores electrical energy from the electric motor when the vehicle in non-drive condition; and
[0008] The limiter circuit is communicatively connected to the level detector. The level detector detects the level of electrical energy remaining in at least one of the primary energy source or the high power density device. This detection is communicated to the Power management system. Power management system in turn activates the limiter circuit to provide the electrical energy to the high power density device when the level of electrical energy of the high power density device is below the second threshold level. The switching unit allows the high power density device to provide additional electrical power to the electric motor to reduce the load power of the primary energy source when the load power of the electric motor exceeds the first threshold level.
[0009] In an embodiment, the high power density device is selected from any one of a super capacitor, a hybrid capacitor, a gold capacitor or a double layer capacitor with a value of ranges from 10 F to 20000F. The high power density device may also be selected from any one of a high power composite lithium based batteries that comprise at least one of a Lithium Titanate (LTO) or lithium compositions, wherein which a high power composite lithium based batteries are high power density cells.
[0010] In another embodiment, the vehicle monitor unit includes a first microcontroller and a plurality of sensors that measure signals associated with each of the one or more vehicle parameters and the one or more path parameters. The first microcontroller in the vehicle monitoring unit processes and communicates the information associated to the load power of the electric motor, acceleration rate of the vehicle, energy levels of the storage devices (high power density device and primary energy source) which is termed as vehicle parameters.
[0011] In yet another embodiment, the limiter circuit includes a unidirectional semiconductor device and a controlled unidirectional semiconductor switch. The unidirectional semiconductor device and the controlled unidirectional semiconductor switch includes at least one of (a) a fast recovery diode, (b) a thyristor or (c) a power transistor.
[0012] In yet another embodiment, the switching unit includes high speed unidirectional switching components, a buffer capacitor, an inductor coil and a freewheeling diode. The one or more of high speed unidirectional switching components are arranged in parallel manner. The high speed unidirectional switching components activates the high power density device to supply the additional electrical power to the electric motor in less than a second in a single sample period when the load power of the electric motor exceeds the first threshold level. The high speed unidirectional switching components includes at least one of (i) a metal oxide semiconductor field effect transistor, (ii) a insulated-gate bipolar transistor, (iii) a fast recovery diode or (iv) a second PN diode.
[0013] The second microcontroller in the power management system receives the information associated with the load power of the electric motor along with the other parameters from the first microcontroller which is in the vehicle monitoring unit. The first microcontroller receives the level of electrical energy remaining in at least one of the primary energy source or the high power density device from the level detector. The second microcontroller calculates the load power of the primary energy source to control the high speed unidirectional switching components for providing the electrical power to the electric motor.
[0014] The buffer capacitor that controls a supply of the electrical energy to the electric motor from and the high power density device. The buffer capacitor includes an electrolytic capacitor. The inductor coil used helps in reduction of ripples in the electrical power that is supplied to the electric motor and also to boost the voltage of the high power density device before supplying to the electric motor. A value of the inductor coil ranges from10 µH to 100 mH and a value of internal resistance of the inductor coil ranges from 1m? to 1?. The freewheeling diode prevents damage to the power assist system that is caused by back electro-magnetic force which is produced by the inductor coil. The second microcontroller is the main component of the power management system to supply the additional electrical power to the electric motor using the high speed unidirectional switching components based on the information associated by the load power of the electric motor and the level of electrical energy remaining in at least one of or the high power density device or primary energy source received from the level detector.
[0015] In yet another embodiment, the conduction ratio between the primary energy source to electric motor and high power density device to electric motor is determined based on the charge level, effective voltage level, internal resistance and temperature along with the back Electro Motive Force (EMF) of the electric motor and one or more path and vehicle parameters.
[0016] In another aspect, a method of reducing a load power of a primary energy source of an electric and a hybrid vehicle includes (i) determining load power of the primary energy source based on one or more vehicle parameters and one or more path parameter using a vehicle monitoring unit, (ii) communicates information associated with the load power of the electric motor to the power management system, (iii) receiving the information associated with the load power of the electric motor using a vehicle monitoring unit, (iv) receiving the level of electrical energy remaining in at least one of the primary energy source or the high power density device using a level detector, (v) determining whether the load power of the primary energy source is exceeds a first threshold level using the power management system (vi) providing additional electrical power to the electric motor when the load power of the primary energy source exceeds the first threshold level using high power density device and (vii) storing electrical energy to the high power density device from the electric motor during non- drive condition by using a regenerative coupling unit.
[0017] In an embodiment, the method includes (i) determining, using a level detector a level of electrical energy remaining in at least one of primary energy source based on at least one of a charge level, a voltage, internal resistance or a temperature of the primary energy source. The level detector determines a level of electrical energy remaining in the high power density device based on voltage of the high power density device and also the conduction ratio between the electric motor and the high power density device and the primary energy source and (ii) communicating, using the level detector the level of electrical energy remaining in the primary energy source and the high power density device to the power management system.
[0018] In yet another embodiment, method includes receiving the level of electrical energy remaining, charge level, voltage, internal resistance and a temperature in the primary energy source and the high power density device using a level detector and providing an electrical energy from the primary energy source to the high power density device when the level of electrical energy of the high power density device is below the second threshold level using the limiter circuit.
[0019] The system responds faster when the load power of the electric motor changes. The described system reduces the discharge power of the primary energy source by a considerable margin. The system improves the performance, effective energy and the usable life cycle of the primary energy source. Using the system, a thermal management becomes lesser significant factor and the acceleration rate can be increased without stressing. The system is able to manage lower capacity of a high power density device effectively. The system will improves the acceleration rate of the electric and hybrid vehicle along with above mentioned parameters. These along with the other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:
[0021] FIG. 1 illustrates a system view to assist power demand requirements based on a load of a vehicle according to an embodiment herein;
[0022] FIG. 2 illustrates an exploded view of a switching unit according to an embodiment herein;
[0023] FIG. 3 illustrates an electric circuit of a limiter according to an embodiment herein;
[0024] FIG: 4 illustrates an electric circuit of regenerative coupling unit according to an embodiment herein;
[0025] FIG. 5 illustrates a graphical view of a switching time of the switching unit of the system according to an embodiment herein;
[0026] FIG. 6 illustrates a flow diagram of a method of managing the power demand requirement of the vehicle using the power assist system according to an embodiment herein; and
[0027] FIG. 7 illustrates a flow diagram of a method of storing regenerative electrical energy using regenerative coupling unit of FIG. 1 according to an embodiment herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following 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.
[0029] As mentioned earlier, there remains a need for a system and method for managing the power demand of the vehicle based on the different load conditions and also to recover the braking energy effectively by regenerative braking.
[0030] Referring now to the drawings and more particularly to FIG. 1 to FIG. 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0031] Definitions: Conduction ratio in term which means that a ratio in a unit time sample when the electrical connection needs to be established between two devices at different time slot. Where a change in conduction ratio means that change in time slot. Conduction ratio = t1: t2, wherein t1 - time slot 1 and t2 - time slot 2. In an embodiment, the time slot 1 (t1) decides that how long the high power density device going to be connected with the electric motor and time slot (t2) decides that how long going to be connected with the electric motor in a unit time sample. The time sample can be 1 second or less than that. Where, the sample time can vary depending upon the speed of load power change. Where the speed of load power change represents the time interval between the previous load power to the present load power.
[0032] FIG. 1 illustrates a system view to assist power demand requirements based on a load of the electric motor according to an embodiment herein. The power assist system includes a primary energy source 102, a high power density device 104, power management system 100, a vehicle monitoring unit 106, a switching unit 108, a level detector 110, a limiter circuit 112, a regenerative coupling unit 117 and an electric motor 114. The primary energy source 102 is electrically connected to an electric motor 114 to provide the electrical energy to the electric motor 114 of the vehicle using the switching unit 108. In an embodiment, the primary energy source 102 includes at least one of lead-acid battery, lithium–ion battery or any alkaline batteries. The high power density device 104 is electrically connected to the electric motor 114 using the switching unit 108. The vehicle monitoring unit 106 determines the load power of the electric motor 114 based on one or more vehicle parameters and one or more path parameters. In an embodiment, the path parameter includes at least one of (a) an inclined or a slope position at which the electric/ hybrid vehicle is running or (b) potholes in a path at which the vehicle is running. The vehicle parameters includes at least one of (a) rate of acceleration of the vehicle or (b) back EMF of the electric motor 114 or (c) charge level related parameters.
[0033] The vehicle monitoring unit 106 includes (i) a first microcontroller that processes and communicates the information associated to the load power of the electric motor 114 that is determined based on the one or more vehicle parameters and the one or more path parameters to the power management system 100 and (ii) one or more sensors that detects and communicates the one or more vehicle parameters and the one or more path parameters to the first microcontroller (Not shown in figures). In another embodiment, the one or more vehicle parameter includes at least one of a level of energy in the primary energy source 102 or a level of energy in the high power density device 104 and the one or more path parameters includes at least one of (a) an inclined or a slope position at which the electrical vehicle is running (b) potholes in a path at which the vehicle is running.
[0034] The level detector 110 communicates the level of electrical energy remaining in the primary energy source 102 and the high power density device 104 to the vehicle monitoring unit 106. The level detector 110 determines the level of electrical energy remaining in 102 based on (i) a charge level, a voltage, internal resistance and a temperature of 102. In an embodiment, the level detector 110 determines the level of electrical energy remaining in the high power density device 104 based on the voltage of the high power density device 104. Additionally, the conduction ratio between the electric motor 114 and the high power density device 104 along with the conduction ratio between the electric motor 114 and the primary energy source 102 is also analyzed. In an embodiment, the level detector 110 determines the temperature level of the high power density device 104 and the primary energy source 102. The limiter circuit 112 can be activated by power management system 100 to provide electrical energy to the high power density device 104 from the primary energy source 102 when the level of electrical energy of 104 is below a second threshold level. In an embodiment, the second threshold level of the high power density device 104 is ranged from 50% to 90% of its maximum voltage level. The high power density device 104 stores the regenerative electrical energy during non drive condition. In an embodiment, if the regenerative energy is not enough to increase the energy level of the high power density device 104 to its maximum acceptable level then the limiter circuit 112 can be activated by power management system 100 to provide electrical energy to 104 the high power density device 104 from the primary energy source 102.
[0035] In an embodiment, the conduction ratio between the primary energy source 102 to the electric motor 114 and the high power density device 104 to the electric motor 114 is determined based on the charge level, effective voltage level, internal resistance and temperature along with the back Electro Motive Force (EMF) of the electric motor 114.
[0036] The vehicle monitoring unit 106 checks whether the load power of the electric motor 114 exceeds a first threshold level. The switching unit 108 allows the high power density device 104 to provide additional electrical power to the electric motor 114 to reduce the load power of 102 when the load power of the electric motor 114 exceeds a first threshold level. In an embodiment, the primary energy source 102 alone provides the electrical energy the electric motor 114 when the load power of the electric motor 114 below a first threshold level. In an embodiment, the switching unit 108 is communicatively connected with the vehicle monitoring unit 106 to provides the additional electrical power to the electric motor 114 from the high power density device 104 based on the information associated with the load power of the electric motor 114 and the level of electrical energy remaining in at least one of the primary energy source 102 or the high power density device 104. In an embodiment, the first threshold level ranges from 0.5 times to 5 times of original power delivering capacity of the primary energy source 102.
[0037] FIG. 2 illustrates an exploded view of the switching unit 108. According to an embodiment herein. The switching unit 108 includes high speed unidirectional switching components 202A-C, a buffer capacitor 204, an inductor coil 206 and a freewheel diode 208. The high speed unidirectional switching components 202B are connected in parallel manner to activate the high power density device 104. In an embodiment, the high speed unidirectional switching components 202B provides an electrical path between the high power density device 104 and the electric motor 114 to supply the additional electrical power to the electric motor 114 in less than a second when the load power of the electric motor 114 exceeds the first threshold level in order to fulfill the load power demand. In an embodiment, the high speed unidirectional switching components 202A-C includes at least one of (i) a metal oxide semiconductor field effect transistor, (ii) an insulated-gate bipolar transistor, (iii) a fast recovery diode or (iv) a PN diode.
[0038] The second microcontroller in the power management system 100 receives the information associated with the load power of the electric motor 114 from the first microcontroller which is a part of the vehicle monitoring unit 106 to determine whether the load power of the electric motor 114 exceeds the first threshold level based on the one or more vehicle parameters and the one or more path parameters. In an embodiment, the second microcontroller receives the level of electrical energy remaining in at least one of the primary energy source 102 or the high power density device 104 using the level detector 110. The buffer capacitor 204 controls the electrical power supply to the electric motor 114 from the primary energy source 102 and the high power density device 104. In an embodiment, the buffer capacitor 204 is an electrolytic capacitor. The inductor coil 206 is electrically connected to the electric motor 114 to reduce ripples in the electrical energy that is supplied to the electric motor 114 and boost the load voltage which needs to be supplied to the electric motor 114. The freewheeling diode 208 prevents the damages to the power management system 100 and the other devices of the power assist system caused by back electro-magnetic force produced by the inductor coil 206.
[0039] In an embodiment, the freewheeling diode 208 provides the alternative electrical path to the back Electro-Motive Force (E.M.F) of the inductor coil 206 which prevents the other units from the electrical and physical damage. In an embodiment, the switching unit 108 includes an invertor 210 that includes at least one of a transistor to transistor logic (TTL), Complementary Metal Oxide Semiconductor (CMOS) or any other logic circuits that produces the inverse signal of its input to control the electrical power to the electric motor 114. In an embodiment, the high speed unidirectional switching component 202C is connected across the buffer capacitor 204 to boost the electrical supply voltage and to supply the electric motor 114 from the high power density device 104. In an embodiment, if the load power of the primary energy source 102 does not exceed the first threshold level then high speed unidirectional switching component 202A provides the electrical energy to the electric motor 114 from the primary energy source 102.
[0040] FIG. 3 illustrates an electric circuit of the limiter 112 according to an embodiment herein. The limiter circuit 112 includes a unidirectional semiconductor device 302 and a controlled unidirectional semiconductor switch 304. The unidirectional semiconductor device 302 and the controlled unidirectional semiconductor switch 304 are communicatively connected with the level detector 110 to monitor the level of electrical energy remaining in the primary energy source 102 and the high power density device 104. The switching unit 108 allows the high power density device 104 to provide the additional electrical power to the electric motor 114 when the load power of the electric motor 114 exceeds the first threshold level. In an embodiment, the power management system 100 activates the limiter circuit 112 to provide electrical energy from primary energy source 102 to the high power density device104 when the level of electrical energy of the high power density device 104 is below the second threshold level. In an embodiment, the high power density device 104 is designed to store the regenerative energy from the electrical motor 114 during non- drive conditions. In another embodiment, if the regenerative energy is not enough to increase the energy level of the high power density device 104 to its acceptable level then the limiter circuit 112 can be activated by power management system 100 to provide electrical energy from primary energy source 102 to the high power density device104.
[0041] In another embodiment, the unidirectional semiconductor device 302 may include PN diode or fast recovery diode and the controlled unidirectional semiconductor switch 304 may include power transistor or thyristors.
[0042] FIG 4 illustrate an electric circuit of regenerative coupling unit according to an embodiment herein. The regenerative coupling unit 117 includes a diode 402, a first switching device 404, an inductor 406, a second switching device 408. The regenerative coupling unit 117 allows the regenerative energy generated from the electric motor 114 to high power density device 104 during non-drive condition (i. e at least one of the time the vehicle is in movement but also when the throttle was in lower position, during braking or declining and so on.). The diode 402, the first switching device 404 and the second switching device 408 are controlled by power management system 100 to provide the regenerative energy in to the high power density device 104 during non-drive condition. The inductor 406 and the second switching device 408 increase the regenerative voltage during non-drive condition before supplying to the high power density device 104.
[0043] FIG. 5 illustrates a graphical view of a switching time of the switching unit 108 of the system according to an embodiment herein. The time period is plotted in X-axis against at least one of a current flow, on/ off time, a root mean square value of current through the primary energy source 102 and high power density device 104, root mean square voltage, power of the buffer capacitor 204. In an embodiment, the current flow includes a value of current flow in the high speed unidirectional switching components 202A-C. The high speed unidirectional switching components 202A-C includes a first Metal Oxide Semiconductor Field Effect Transistor (MOSFET) or first Insulated Gate Bipolar Transistor (IGBT) with serial diodes (only in 202A & 202B), an inductor coil 206, a second PN diode and a second Metal Oxide Semiconductor Field Effect Transistor (MOSFET) or second Insulated Gate Bipolar Transistor (IGBT) with serial diode. The high speed unidirectional switching components 202A-C combines the electrical power of primary energy source 102 and high power density device 104 to provide electrical energy to the electric motor 114 in at least one of (i) single sample period of one second or (ii) less than that. In an embodiment, a period of the sample is determined based on the response time required to fulfill the load power demand.
[0044] FIG. 6 illustrates a flow diagram of a method of managing the power demand requirement of the vehicle using the power assist system of FIG. 1 according to an embodiment herein. At step 602, one or more vehicle parameters and one or more path parameter is received using a vehicle monitoring unit 106 to determine a load power of the primary energy source 102. In an embodiment, the load power of the primary energy source 102 increases when the load power of the electric motor 114 is increased. At step 604, the information associated with the load power of the primary energy source 102 from the vehicle monitoring unit 106 and the level of electrical energy remaining in at least one of the primary energy source 102 or the high power density device 104 is analyzed by the power management system 100 from the level detector 110. At step 606, the load power of the primary energy source 102 checked by power management system 100, whether it exceeds the first threshold level based on the information associated with the load power of the electric motor 114 and the level of electrical energy remaining in at least one of the primary energy source 102 or the high power density device 104. At step 608, additional electrical power is provided to the electric motor 114 using high power density device 104 when the load power of the primary energy source 102 exceeds the first threshold value, else continue the step 606. In an embodiment, the method includes the step of receiving using a level detector 110, at least one of the levels of electrical energy remaining based on the following charge level, voltage, internal resistance, temperature and other parameters related to the primary energy source 102 and the high power density device 104. The electrical energy is provided from the primary energy source 102 to the high power density device 104 using the limiter circuit 112 when the level of electrical energy of the high power density device 104 is below the second threshold level. The first threshold level ranges from 0.5 times to 5 times original power carrying capacity of the primary energy source 102.
[0045] FIG. 7 illustrates a flow diagram of a method of storing regenerative electrical energy using regenerative coupling unit of FIG. 1 according to an embodiment herein. At step 702, the power management system 100 checks the vehicle movement using the information provided by the first microcontroller of the vehicle monitoring unit 106. In an embodiment, one of the important but not limited to the information which mentioned above and also back e.m.f of the electric motor 114. At step 704, the power management system 100 checks the throttle position of the vehicle using the information provided by the first microcontroller of the vehicle monitoring unit 106 to determine the throttle voltage. In an embodiment, one of the important parameter to check the regenerative braking energy is to inspect if the motor 114 current flows from primary energy source 102 or high power density device 104 to electric motor 114. At step 706, the power management system 100 deactivates regenerative coupling unit 116 when the vehicle is not in motion. At step 708, the power management system 100 activates regenerative coupling unit 116 to store the electric energy of regenerative electrical energy in the high power density device 104 when regenerative braking is detected using the vehicle monitoring unit 106. In an embodiment, the regenerative braking is detected when at least one of the positions of the throttle is in deceleration or the time of brake applied.
[0046] 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 appended claims.