This document describes a project to design and control a hybrid energy storage system for a small plug-in electric vehicle. A battery and supercapacitor are used along with a multi-port converter. A permanent magnet brushless DC motor is used to drive the vehicle in four quadrants for forward, reverse, and regenerative braking modes. MATLAB simulation models are developed to model the power management system, motor drive, speed and current controllers, and vehicle dynamics. A DSP controller is used for hardware implementation, including driver circuits and interfacing with hall sensors to generate PWM signals for motor control. Future work includes integrating the power circuit with the motor, designing controllers for the bi-directional converter, implementing regenerative braking algorithms

1. Design and Control of Hybrid Energy Storage
System based Small Plug-in Electric Vehicle
Supervisor
Phaneendra Babu Bobba,
Department of Electrical Engineering, Shiv Nadar University.
Students
I. Malyala Varun, AAA0204, Electrical Engineering, Shiv Nadar University
II. Priyam Avasthy, AAA0212, Electrical Engineering, Shiv Nadar University
III. Vavya Chopra, AAA0232, Electrical Engineering, Shiv Nadar University

2. Contents
Abstract.............................................................................................................................................................................3
Block Diagram of the Project ............................................................................................................................................3
Power Management .........................................................................................................................................................4
Bidirectional Converter:......................................................................................................................5
Simulation 1: Permanent Magnet Brushless DC Motor Drive ..........................................................................................6
Speed Controller ...............................................................................................................................................................7
Hysteresis Current Control........................................................................................................................................7
Modes of Operation – Switching Logic [2]........................................................................................................................8
Vehicle Dynamics [3].........................................................................................................................................................8
Model parameters for simulation.....................................................................................................................................8
Results...............................................................................................................................................................................9
Hardware Implementation ...............................................................................................................................................9
Driver circuit using IR2101..................................................................................................................9
Hall Sensor Interfacing Circuit...........................................................................................................10
Generating PWM outputs from hall signals....................................................................................................................10
Simulation - Work Plan [4]..............................................................................................................................................11
Future Work....................................................................................................................................................................11

3. Abstract
In this project, a hybrid system based on battery and super capacitor along with multi-port converter.
PMBLDC motor is used to drive the vehicle and it is operated in four quadrant mode i.e. forward and reverse
regenerative braking mode and motoring mode. Power transfer from different energy sources is controlled by multi-
port converter and a phase-shifted PWM technique is implemented to ensure the proper operation of the storage
devices based load requirements of the electric vehicle. For proper modelling and verification, a MATLAB based
simulation model is developed. Vehicle Dynamics are also incorporated for testing the performance of the electric
vehicle. For the hardware implementation, TI controller TMDSPREX28335 is used as a central control unit to monitor
the control variables and also to generate switching pulses to the inverters and multi-port converter based on load
requirement.
Block Diagram of the Project

4. Power Management
In this particular project, 16.2V, 58F ultracapacitor has been used in the circuit to ensure the prototype speed of
15kmph. Ultracapacitor has an internal series resistance and a significantly high resistance in parallel.
The ultracapacitor model was implemented in MATLAB using the given circuit to analyze the charging and
discharging pattern and check the same for a real-time application.
A capacitor (with a very small series resistance) and a significantly large parallel resistance was connected to a DC
power source and resistive load through two switches who were activated by out-of-phase pulses (from the
generator). When the first switch was ON, the supercapacitor was discharged against the load. During the turn OFF
instant of the first switch, the second switch was turned on the capacitor was charged by the battery.
First graph indicates the charging/discharging characteristics of the capacitor against a load of 100 ohms. The second
graphs is the overlap of the pulse given to the second switch (for charging) and the charging instant of the capacitor.
The charging and discharging time for the hardware model of the supercapicitor were calculated using the following
circuit. The resistance was maintained such that no more 2A could flow within the circuit. The DC voltage was
maintained to provide a current of minimal value so that the capacitor (which has low resistance) does not get
damaged
Following are the DSO outputs indicating the charging and discharging pattern of the hardware supercapacitor
circuit.

5. Bidirectional Converter:
This is the simulation of bidirectional converter. However it’s still not working in motoring and regenerating mode.
.The values used here for different parameters has been calculated using formulae and some assumptionsValue of
capacitance is decided in accordance with the current it can allow to pass through it without any damage and will
reduce ripple and very small values of resistors are used because voltage source and capacitor can never be
connected in parallel

6. Simulation 1: Permanent Magnet Brushless DC Motor Drive

7. Speed Controller
Current Control [1]
Hysteresis Current Control

8. Modes of Operation – Switching Logic [2]
Vehicle Dynamics [3]
Model parameters for simulation
Battery:
Nominal_Voltage = 48;Rated_Capacity = 20;Initial_SOC = 80;
Control:
Speed_Cutoff_Freq = 285;Speed_Proportional_Gain = 4.9220; Speed_Integral_Gain =
446.7600;Speed_Torque_Saturation = [-17.3000, 17.3000];
Speed_Cutoff_Freq_Reg = 285;Speed_Proportional_Gain_Reg = 4.92; Speed_Integral_Gain_Reg =
446.76;Speed_Torque_Saturation_Reg = [-17.3000, 17.3000];
Hysteresis_Band = 0.0100; Hysteresis_Band_Motoring = 0.01;Hysteresis_Band_RegBrake = 0.01 ;
Inverter:
Rs = 66; Cs = 3.0000e-07;
Motor:
Rs = 0.1800; Ls = 5.4000e-04; Flux_Linkage = 0.0276;Inertia = 0.1324;Viscous_Damping = 0.0516;Poles = 23; Ke =
133;
Vehicle Dynamics:
Mass = 175; Tire_Radius = 0.2000;Aero_Drag_Coeff = 0.9200; Frontal_Area = 0.6000; Wind_Velocity = 0;
Air_Density = 1.2300; Gravitational_Constant = 9.8100; Gradient_Angle = 0; Rolling_Resistance = 0.0180;

9. Results
Hardware Implementation
For the presented application, the TMS320C28335 DSP is chosen. It consist on a logic integrated circuit mounted in
an auxiliary board (F28335 Zdsp). This device provides the necessary supply connections for the TMS320c28335 to
be run and programmed. The DSP clock is of 150 MHz and needs to be supplied with 3.3 V. It is able to do hardware
PWM signals and includes several ADC converters. The DSP is programmed in Simulink interface which in turn
generates C code. Code Composer Studio compiler is used to compile and interface between the system and the
controller. Using this programmable device to control the converter assures enough computation speed and it also
has the advantage that it can operate with floating point, therefore, operations are very easily done.
Driver circuit using IR2101
For the hardware part, we have one leg of converter and to run it we have made a driver circuit using IC IR2101.
The circuit is complete but when we tried giving it pulses through function generator, it didn’t work because of the
current rating being very low.
We have designed RC snubber circuit to connect across switching device to limit the dv/dt.
We have used these values : 𝐼 𝑝𝑘 = 25 𝐴, 𝑉𝑟𝑎𝑖𝑙 = 15 𝑉 , 𝑟𝑖𝑠𝑒 𝑡𝑖𝑚𝑒 = 𝑑𝑡 = 50𝑛𝑠 , 𝑓 = 20𝑘𝐻𝑧
And got this results, C =66.66 nF, R = 37.5 ῼ P = .15 W
Since the power is very low, we have used normal resistors for this purpose.

10. Hall Sensor Interfacing Circuit
Generating PWM outputs from hall signals
2 Output: Hall PWM Output Ha Ha
2 Hall Sensor Interfacing Circuit using TLC272CP

11. Simulation - Work Plan [4]
All the parameters for this simulation are taken from standard research papers. Modelling of speed and
current controllers have been done using PI controller with some more features. Speed PI gain values have been
optimised using Ziegler - Nichols tuning method. Current controller although is a PI is just used for limiting range
between zero and one. In the current controller, hysteresis current control and pwm current control have been used
and performance is analysed and pwm current control has been selected for further research work. The forces which
the electric machine of the vehicle must overcome are the forces due to gravity, wind, rolling resistance, and inertial
effect and the EV propulsion system is modelled to meet the design requirements.
Various machine parameters such as rotor resistance, rotor inductance, inertia of the machine and voltage
constant have been measured. Controller has been successfully interfaced with Simulink and Code Composer Studio.
Hall sensor to controller interfacing circuits and gate driver circuits have been fabricated and tested. Decoder pulses
have been successfully generated and brushless dc motor is run in open loop using hall signals successfully.
Future Work
The power circuit will be integrated with the motor and the close control loop. The values of currents,
battery’s state of charge and voltage will be fed back by the control circuit to the converter and the acceleration and
retardation will be determined on the basis of the above parameters. The control of switches and designing of speed
and current controller for the bidirectional converter such that the converter will operate in four quadrant is to be
done. After which we have to give switching pulses to the one leg converter and we will have to integrate the load
with the Bi- directional converter.
Current PI will be tuned accordingly to reduce the ripple and optimise power using Ziegler - Nichols tuning
method. In Vehicle Dynamics, state flow model for a hybrid sources depending on speed and acceleration or brake
mechanism is proposed for a better implementation. Mechanical braking and simulation for a full urban cycle will be
included in the future simulation. Rigorous regenerative braking algorithms will be implemented for effective
braking.
Current sensors and voltage sensor should designed to meet the requirement of the controller and will be
fed into ADC of the controller. Various control algorithms should be implemented to incorporate current feedback
into the existing system. Speed measurement should be done by configure the eCAP pins in the controller to
incorporate speed feedback into the system.
Bibliography
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Regeneration for Electric Vehicles.
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[4] J. Faiz, M. Azizian and M. Aboulghasemian-Azami, Simulation and analysis of brushless DC motor drives using
hysteresis, ramp comparison and predictive current control techniques.
[5] P. PRGASAN and R. KNSHNAN, Modeling of Permanent Magnet Motor Drives.
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