UWE Bristol Engineering showcase 2015

SHARIFAH FARAHANA FITRAH SYED IDRIS
MENG ELECTRICAL & ELECTRONIC ENGINEERING
ENERGY STORAGE EXERCISE EQUIPMENT
A study of the benefits of retrofitting cardiovascular exercise equipment of a gym with human energy
harvesting technology and an analysis of installation of PWM buck-boost converter for battery charge controller.
PWM Buck-Boost Controller for
Battery Charger
The controller of a buck-boost converter has its own purpose of controlling
the output voltage and protecting the converter by limiting the output current
to a predetermined value. The normal mode for controlling only regulates the
output voltage for example; the controller need to control the converter to
keep the current from going over the maximum limit if the loads like the
converter output voltage causes the current run over the limit. A current
regulation is important in the control system of the buck-boost converter and
has priority over all the other tasks including the voltage regulation as it
functions for safety. Besides, preserving the current below its maximum is
important to protect the converter and load from overheating. Therefore,
PWM is a key element in controlling the buck-boost converter.
When supply voltage is close to the desired load voltage, the converter is
set to buck-boost operation. In this mode, S1 and S4 work as a group (C1)
and S2 and S3 work as another group (C2). To charge the inductor,
controller C1 is closed and C2 are open. C1 is open and C2 is closed to
engage the inductor discharge cycle. In this mode, average load voltage
VV oooooo equals D(1-D) VV ss . This implies that output voltage can be changes to
more or less than the supplied voltage. Table shows the summary of power
converter operation.
DC motorgenerator
set
Project Supervisor(s)
DR. ROHITHA WEERASINGHE
DR. MOKHTAR NIBOUCHE
Project summary
This paper presents an energy harvesting with energy
storage for exercise equipment system. In this study,
the author demonstrates how it is possible to
generate useful electricity with an exercise bike
system. In addition this study deals with a buck-boost
converter and the inverter to stabilize the generated
voltage and charge batteries with it. The system
consists of a DC motor power generator and highly
efficient energy harvesting circuit implemented in
PSCAD/EMTDC software and developed as a
prototype. By introducing a PWM control technique
into the DC-to-DC Buck-Boost Converter, the energy
harvesting circuit can adjust the duty ratio of the
converter following the variation of the input voltage
and the voltage of energy storage element to get high
energy conversion efficiency.
Project Objectives
To investigate the design and implementation of
energy harvesting system with energy storage that
harvest the motion energy being generated by
exercise equipment’s user in a gym and converting
it to electrical energy. implement a good battery
charger to extend the battery’s life. However, this
general objective can be broken down to four
more specific objectives that would together
achieve the overall goal of the project:
To design the energy harvesting system in PSCAD
simulation software,
To analyse the efficiency improvement with the
installation of energy storage in power system,
To design buck-boost PWM converter charge
controller converter
Flow of Energy Storage Exercise Equipment using Energy
Harvesting Concept
Buck-boost
controller
Battery
Project Conclusion
To conclude, this study has developed a PWM buckboost
charge controller for the energy storage of
energy harvesting energy system that is implemented
in a gym. The advantage of this method is definitely
for battery safety; prolong the battery’s life, and by
using this controller the battery will be not
overcharged.