Claims:Claims:
We Claim:

1. Economical & Compact Design- The Bi-facial/bi-directional converter structure not only drives the e-bike but also recycles energy produced by Back EMF during motoring operation and uses it for charging the battery(source).

2. Integrated State of Charge (SoC) is an added feature proposed as an addition to the converter in order to minimize charging time.

3. It also employs less number switching components to facilitate propulsion and regenerative braking in e-bikes.
, Description:An economical and compact size integrated with SOC estimation Function for charging the battery from the back electromotive force (BEMF) used in bifacial power converter drive e-bike is proposed. The Main system consists of source as battery, bi facial buck boost converter, inverter to fed the drive system. Besides, the bifacial converter is also set out as a charger, to charge the battery which converted the rectified voltage from AC as described in Figure 1.1 & Figure 1.2. The bifacial converter consists of three switches integrates the motor driver part with inverter to drive e-bike and also uses the same converter to charge the battery with its Back EMF. Additionally, back up rectifier circuit for charging the battery is also attached. These will work along with estimation of SOC strategies embedded with the system and indicated through LCD to promote the reliability of system. The proposed system operation is divided into two modes of operation as shown in Figure 1.4 i.e., Motor driving Mode and Battery charging mode. In motor driving mode (Motoring Mode), system behaves as a non-isolated buck converter in which energy transfer will takes place from battery(source) to motor (load- E-bike). Thus, Back EMF will start generating by the motor. When the Back EMF produced is greater than the battery voltage, it will act as a source and step down the voltage to charge the battery via bi-facial converter by recycling the energy generated by the back emf and reused for recharging the battery. In case back emf is lower than battery voltage, then step up the DC voltage to charge the battery again via bi-facial converter. In Battery charging mode, initially voltage level and State of Charge (SoC) is estimated. Then check the estimated value of SoC is greater than 90%, then Constant Voltage (C-V) charging is employed else Constant Current (C-C) charging is used to reduce the charging time by using a separate rectifier circuit. Thus, proposed invention not only transfers the energy stored in battery for driving the motor, but also reclaim the energy resulted from the back electromotive force for charging battery. However, the State of Charge (SOC) estimation function of battery is also integrated with the proposed bi-facial converter help to compress size, cost and ease to control.