FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
PROVISIONAL / COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Topic - Regenerative Braking in an Electric Two Wheeler using
Supercapacitors.
2. (a) Name - Karandikar Parashuram Balwant
(b) Address - 5/5 Golf Residency, Yerawada, Pune 411006, Maharashtra, India
(c) Nationality - Indian

Description :-
We, the inventors of the invention "Regenerative Braking in an Electric Two Wheeler using Supercapacitors" have accomplished the preceding objectives of the invention and have overcome the problems and shortcomings associated with prior art techniques and approaches by the present invention as described below, in the preferred embodiment. We have substantially illustrated this invention in the accompanying drawings, throughout which reference letters indicate corresponding parts in the various figures.

Title of the Invention:
Regenerative Braking in an electric two wheeler using Supercapacitors.
Field of Invention:
The present invention talks about the application of supercapacitors in electric two wheelers for regenerative braking. This invention also represents the use of Direct Current (DC) hub motor for running the two wheeler and regenerating the braking energy using supercapacitors.
Prior art and its limitations and drawbacks:
Due to the rapid development, economic growth, high population density, and tropical climate, scooters/ motorcycles are the most popular vehicles in many under developed countries. However, in order to cope with the harmful effects on the environment such as serious air and noise pollution in urban areas and depleting energy resources, the development of zero-emission electric vehicles is gaining importance on a global scale. Electric vehicles are gaining popularity among vehicle constructors, governments, and consumers in this regard. But there are problems associated with these vehicles.
The range of these vehicles is quite less when compared to conventional vehicles burning fossil fuels. Technologies like regenerative braking have been used to improve the range of these vehicles. This technology helps to salvage the energy that would have been otherwise lost in frictional braking. This is done by converting the kinetic energy of a moving vehicle into electrical energy and then storing it for future use. But such a technology has never been used on a two-wheeler; the basic reason for this being that, two wheelers are light and kinetic energy associated with

them is less. Thus, the energy recovered will also be less. But, because of the huge number of two wheelers, the amount of energy that could be recovered is significant. There are more than 35 million two wheelers in a country like India by the end of 2010. In the future it is possible that many of these two wheelers would be electrically powered and even if a small amount of energy can be recovered from the braking of every such electric two wheeler, the overall energy savings would be tremendous. In the long run, its contribution towards energy saving will be important.
Another great problem with these vehicles is that the batteries are not suitable for supplying high currents required by the motor. This is because a battery is a high energy density device and not a high power density device. This means that a battery is not good for supplying very high currents for small periods of time. On the other hand, devices called supercapacitors are excellent high power density devices. They can supply hundreds of amperes of current for a few seconds. Therefore, if we can use the two together along with regenerative braking in a two wheeler, we will not only improve the range of the vehicle but also increase the battery life.
It is evident from the above description, that there is a need to fit an electrically powered two wheeler with a regenerative system that uses a battery and a supercapacitor together and thus get rid of the disadvantages of conventional electric powered two-wheelers.
Objective and summary of invention:
1. To develop a zero emission vehicle.
2. To ensure easy energy storage and a power booster in electric vehicles.
3. To increase the life of the battery and the range of electric vehicles.

4. To recover the kinetic energy of moving electric vehicles during braking.
5. To convert kinetic energy to electrical energy and to ensure its storage in some electrical device to provide the extra push required during start and acceleration.
6. To use supercapacitors to augment the regenerative effect on an electrically operated two wheeler.
7. To recover the braking energy by means of the supercapacitor technology and reduce stress on the battery pack, resulting in longer battery life.
8. To increase the range of the vehicle and salvage lost energy.
To achieve the objectives mentioned above, the present invention makes use of a motorized bicycle with a rear wheel drive with the help of a Brushless Direct Current (BLDC) hub motor. It is preferred to use a brushless motor to avoid sparking and wearing out of brushes. Ideally, the motor used to drive the system, itself, should operate as a generator to facilitate regeneration. Most of the BLDC hub motors designed is suitable for motoring action only. So, to overcome this problem, a standard alternator with rectifier of any mid- segment car is used. A BLDC hub motor of at least 200rpm with minimum 6 volts voltage rating is used along with an alternator of voltage rating to match the said hub motor. As the speeds of both said machines don't match exactly, so a conventional power transmission system of atleast two stage pulley-belt arrangement consisting of a suitable number of pulleys to increase the speed by a ratio so as to match the speeds of the alternator and the motor. Any pulley-belt combination is preferred because it works without any maintenance and without the addition of significant system weight. Any appropriate battery with a voltage rating matching the said hub motor is used as a storage device and to supply power to the motor. At least two supercapacitor banks of voltage rating to match the said

hub motor are connected, one by one, across the alternator during charging i.e. regeneration and during discharging; they are connected in series to obtain a voltage greater than the voltage across the said motor to feed the starting or acceleration current. The said supercapacitor bank is connected across the alternator to store the energy generated during braking. During regenerative braking, the supercapacitor bank may possess any voltage and from that, it is required to get fully charged to use the stored charge for subsequent starting/ acceleration. Maximum current is drawn by a motor during starting, thereby stressing the battery. A supercapacitor can improve the acceleration performance of the vehicle by providing a large current in short time, delivering extra energy to meet the energy requirement when it is needed. Without the aid of the said supercapacitor bank, the said battery will have to supply a surge of current during starting, but the supercapacitor bank limits this value to a very small quantity. This not only increases the range (in terms of distance) of the system but also prolongs battery life, by reducing the peak current being supplied by the battery. Hence, battery maintenance and battery replacement frequency reduces which reduces the running cost of the motorized bicycle. Thus, according to the method of the present invention, all the objectives mentioned above are achieved.
Statement of invention:
Steps involved in the implementation of regenerative braking in a motorized bicycle using supercapacitor are:
1. Motorizing the bicycle with the rear wheel drive using a BLDC hub motor of at least 6 volts voltage rating and minimum 200rpm speed.
2. Any suitable battery voltage compatible with the said BLDC hub motor is used as a power source.

3. Attachment of the voltage compatible standard alternator with rectifier of any mid segment car, to the bicycle frame.
4. Coupling of the BLDC hub motor with alternator with the help of any conventional power transmission increasing the speed in a ratio in accordance with the speed of the alternator and that of the BLDC motor.
5. Connection of the alternator with the supercapacitor banks.
6. Connection of the super capacitor bank with the BLDC motor using power diodes for supplying high starting and accelerating currents.
7. Connection of specially designed, electronic cum mechanical brake to the alternator.
The said BLDC hub motor used is of at least 6V voltage rating, at least 150W power rating and at least 200rpm speed or it is any other DC hub motor capable of regenerating power with at least said voltage, power and speed rating without the use of an alternator and pulley arrangement.
Any standard alternator with rectifier of voltage rating to match the said hub motor (with non regenerating capability) and at least 2100rpm speed is used.
Any appropriate battery with a voltage rating matching the said hub motor and at least 7Ah current is used as a storage device and to supply power to the motor. .
The electronic cum mechanical brake consists of an SPST (Single Pull Single Throw) switch followed by a mechanical switch having a spring of higher spring constant than the spring used in the SPST switch, operated by a common hand lever.

Description of Figures:
1. Fig 1 shows the arrangement for regenerative braking using pulley transmission system in the rear wheel of the two wheeler according to the present invention.
2. Fig 2 shows the detailed isometric view of pulley transmission system connecting the hub motor with the alternator needed for the present invention.
3. Fig 3 shows the arrangement for regenerative braking using only a DC hub motor in the rear wheel of the two wheeler according to the present invention.
4. Fig 4(a) shows the regenerative braking circuit/scheme using supercapacitors with BLDC hub motor and alternator for the present invention.
5. Fig 4(b) shows the regenerative braking circuit/scheme using supercapacitors with DC machine capable of both motoring and generating for the present invention.
6. Fig 5 shows the two wheeler handle for electric and manual braking in the present invention.
Description:
Figure 1 is the prospective view of the two wheeler showing its different components. Since the whole idea is to run the vehicle electrically, so an electric motorized bicycle is designed and fabricated with a single seater (6) and instead of running it on a chain and sprocket mechanism using a pedal, a brushless hub DC motor (16) of at least 6 volts voltage rating with at least

200rpm speed is fixed in its rear wheel (37) to generate motoring action to drive the said bicycle. The said brushless DC motor (16) is free from sparking and brushes which wear out after some time. Ideally, the said motor (16) used to drive the said bicycle, itself, should operate as a generator to facilitate regeneration, but the availability of such a low voltage BLDC hub motor (16) is an issue and hence the use of a generator (17) was inevitable. Low speed, low voltage, at least 6 volts, 200rpm generators of smaller capacity are not used in many applications. Thus the only choice that remains is the use of existing high speed generators. As a result, any standard alternator (17) with rectifier of at least 2100rpm speed and voltage rating same as that of the DC hub motor (16) of any passenger car is used along with a speed reduction power transmission system, shown in figure 2 in the form of a two stage pulley-belt system. From here on, alternator (17) refers to alternator with rectifier.
In the present invention, a belt - pulley system is employed, as shown in figure 2 because it is the best choice for speed reduction that works without any maintenance and without the addition of significant system weight. The v-belt (14, 15) has high efficiency. A v-belt based pulley transmission system is used in the present invention to connect the BLDC hub motor (16) with the alternator (17). To achieve the idle speed of the alternator (17) from the BLDC motor (16), at least two stage pulley-belt arrangements having speed ratio of at least 1:4 in each stage is used. Intermediate shafts (22) for more than one stage pulley system are employed on strength basis for static and fatigue loading. Ball bearings (21) with housing are selected based on their dynamic capacity behavior to support the said intermediate shafts (22). Both the said ball bearings (21) and the alternator (17) are fixed to the electric bicycle chassis (5) using mild steel frame (18, 20) designed for the present invention.

In the present invention, any type of battery (7) of voltage rating same as that of said BLDC hub motor (16) is used for driving the two wheeler. The supercapacitor (9) is used for energy conservation in the present invention. The working voltage of each said supercapacitor (9) is in the range of 1-3 volts. To meet the requirements of high voltage, supercapacitor banks (8) are created by connecting said supercapacitors (9) in series such that it matches the voltage rating of the said battery (7). At least two said banks (8) are connected one by one across the alternator (17) during charging i.e. regeneration and during discharging; they are in series in such a way that their output voltage matches with that of the BLDC hub motor (16). The characteristics of the said super capacitor (9) and battery (7) are complimentary to each other and hence they make a good power source for regeneration in electric operated vehicles.
There are two types of controls in the present invention, the first control circuit is connected to the said BLDC Motor (16) for speed variation in the vehicle and the second is the supercapacitor - battery change over system, shown in the figure 4. The said brushless hub DC motor (16) requires a specialized control circuit which is inbuilt within the DC hub motor (16) used in electric vehicle applications. The said changeover circuit, shown in figure 4, connects the said supercapacitor banks (8) in series and uses diodes (26, 27) to control the direction of flow of current. The said supercapacitor bank (8) is connected across the alternator (17) to store the energy generated during braking.
The braking distance in the present invention depends on the charge on the said supercapacitor bank (8) at the time when the brakes are applied. For the long braking distance in case of low initial charge in the said supercapacitor bank (8), the vehicle is decelerating and not braking. To reduce the braking distance so as to stop the vehicle immediately, frictional brakes are also applied along with the electronic braking if in case the initial

charge in the said supercapacitor bank (8) is less. The system used to apply electric and mechanical braking in the present invention is known as semi -electric hand brake system, shown in figure 5. This semi - electric hand brake system can be used in two cases:- one, if the rider wants to decelerate the vehicle then he just applies the brake (33) slightly and electric brakes are applied through momentary action of single pull single throw (SPST) switch (34). The said SPST switch (34) mounted on the brake handle (36) connects the circuit that provides field current to the said alternator (17); second if the rider wants to stop the vehicle immediately, he applies the brakes (33) completely and both electric and mechanical brakes are engaged. The spring constant of the spring in the momentary action SPST switch (34) is less than the spring constant of spring S (35). This ensures that only if the said switch (34) is closed when the brakes are engaged, the spring S (35) gets compressed and mechanical brakes are applied. Therefore, electric brakes are engaged before mechanical brakes.
In the present invention, the two wheeler is driven to a rated speed of at least 21 km/h and electrical brakes are applied to capture the braking energy which is pushed in one of the said supercapacitor banks (8) of voltage rating same as that of the battery (7).
In the present invention, the performance of the said supercapacitor bank (8) under braking dynamics of a two wheeler is studied by charging the supercapacitor bank (8) at different standard initial conditions. The inventors, declare that it is observed from the above study that more energy can be regenerated if the said supercapacitor bank (8) is partially charged because the power is the product of voltage and current. Initially, the voltage is less, thus power is less. Later on, as the said supercapacitor bank (8) keeps charging to different voltage levels, power again starts decreasing.

This is because of the charging characteristics of a capacitor (rate of charging keeps decreasing). Hence it is advisable to charge the said supercapacitor bank (8) through a battery to at least 20% of its maximum value and then regenerate energy in every broking to use it for subsequent starting/ acceleration.
To reduce the manufacturing cost and to improve the efficiency of the present invention, one of our primary endeavors, a conventional DC hub machine (25) which is capable of motoring and regeneration is a better option with an appropriate controller and mechanical construction. We, the inventors ensure that the said system would improve the overall efficiency of any two wheelers as there will not be any need of an extra alternator (17). Also the losses in the said belts and pulleys WILL be eliminated. This system with a cnnventinoal DC motor (25) has been demonstrated in the figure 3. In this scheme, during regenerative braking, the field winding supply is not disconnected. However, the armature terminus are disconnected and are connected across the supercapacitor bank (8) to store the recovered energy. This is achieved through proper DC- DC converter (40) operating in coordination with suitable switching operations between the supercapacitor bank (8) and the battery (7) to the motor (25).
We strongly affirm herein, that a supercapacitor based system with the above process according to the present invention is extremely suitable for energy conservation in pulse power operation. The recovering of the braking energy by means of the supercapacitor technology reduces stress on the battery pack, resulting in longer battery life, it substantially increases the range of the vehicle and salvages lost energy.
The present invention also states that the use of any conventional DC hub machine, capable of motoring and regeneration can eliminate the mechanical

power transmission system and separate generator and thereby recapture energy during regeneration more efficiently.
Hence, according to the procedure of the present invention all the objectives mentioned above are achieved.
The foregoing objectives of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment.
Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter.
The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention; which is defined by the scope of the claims to follow.

Advantages of invention:
1. The present invention achieves partial salvage of the kinetic energy previously dissipating due to heat energy.
2. The present invention requires no fuel; hence, it helps to conserve depleting conventional energy reserves.
3. The present invention is a zero emission vehicle causing no pollution.
4. The present invention is an electric vehicle with both pulse and continuous power as required.
5. The present invention exhibits high energy density resulting in a long cruising distance, less charging time for the battery and longer battery life.
6. The present invention ensures reduced stress on the battery pack.
7. The present invention achieves improved acceleration performance due to provision of large instantaneous current during starting.
8. The present invention features a reduced running cost due to reduced battery maintenance and battery replacement frequency.
9. The present invention boasts enhanced energy storage using a battery as well as a capacitor.

10. The present invention achieves augmented range of the vehicle after few braking cycles.
11. The present invention ensures a reduction in battery size, making the vehicle less bulky.

Claims: We claim:
1. Method of implementation of regenerative braking system in an
electrically operated two wheeler, comprising of:
a) A Brushless Direct Current (BLDC) hub motor on the rear wheel; said hub motor having a voltage rating of at least 6 volts and speed of at least 200rpm.
b) A standard alternator with rectifier, of a mid segment car; said alternator having a voltage rating matching that of the hub motor with speed of at least 2100rpm.
c) The said BLDC hub motor connected with the said alternator using any conventional power transmission system; the overall speed ratio of said power transmission system being at least 1:1.1.
d) Any type of battery, the said battery being connected to the BLDC motor and having the same voltage rating as that of the BLDC hub motor with at least 7Ah current.
e) Two types of controls, the said controls being a control circuit with BLDC hub motor for speed variation of the vehicle and a supercapacitor change over system to operate electric braking prior to the mechanical braking.

2. Method of utilizing supercapacitor bank having voltage rating same as that of BLDC hub motor to store energy regenerated in braking in an electrically operated two wheeler.
3. a) Method of utilizing at least two supercapacitor banks claimed in claim 2 to store energy regenerated in braking in an electrically operated two wheeler.

b) Method of utilizing supercapacitor banks as claimed in claim 3 (a) wherein the banks are connected one by one across the alternator during charging or regeneration.
c) Method of utilizing supercapacitor banks as claimed in claim 3 (a) wherein the banks are connected in series during discharging to obtain the voltage higher than the rated voltage of the BLDC hub motor.
d) Method of utilizing supercapacitor banks as claimed in claim 3 (a) to 3 (c) wherein the supercapacitor bank is charged to at least 20% of its maximum value initially for effective regenerative braking.

4. Recovering of available mechanical energy in the form of DC power stored in supercapacitor bank as claimed in claim 2.
5. Method of utilizing frictional brakes along with the electronic brakes for decelerating and stopping the vehicle wherein electronic brakes are applied via an SPST (Single Pull Single Throw) switch.

6. Method of utilizing frictional brakes along with electronic brakes as claimed in claim 5 wherein the SPST switch connects the circuit that provides field current to the alternator.
7. Method of utilizing frictional brakes along with electronic brakes as claimed in claim 5 wherein the electronic brake is applied via SPST switch before the mechanical brake which employs a spring of higher spring constant than the SPST switch.
8. Method of utilizing supercapacitors with a conventional DC hub machine capable of motoring and regeneration which eliminates the separate mechanical power transmission system and generator to recapture energy more efficiently.

9. Method of utilizing supercapacitors with a conventional DC hub machine
capable of regeneration, in which the regenerated energy is pushed back
into the supercapacitors by disconnecting the armature from the supply and
connecting it to the super capacitor bank.
10. Method of using the stored energy in supercapacitors for subsequent
starting or acceleration of the vehicle.

Inventory of the parts of the invention:
5 - Electric Cycle Frame
6 - Seat
7 -Battery
8 - Supercapacitor Bank
9 - Supercapacitor

14 - V Belt 1
15 - V Belt 2
16 - Brushless Direct Current (BLDC) Hub Motor
17 - Alternator with Rectifier
18 - Supporting Fixture for Intermediate Shaft

20 - Supporting Fixture for Alternator
21 - Bearing
22 - Intermediate Shaft

25 - Direct Current Hub Motor with Regenerating Capability
26 - Diode Dl
27 - Diode D2

33 - Brake lever
34 - Single pole single throw switch
35 - Mechanical Spring S

36 - Brake Handle
37 - Rear Wheel Rim 40 - DC-DC Converter