Hybrid Go-Kart ECE4901 Fall 2013 Project Statement Team 187: Jonathan Blake (EE) Nathan Butterfield (EE) Joshua Calkins (EE) Anupam Ojha (EE) Advisor: Prof. Sung-Yeul Park
1 1. Statement of Need: The 21st century faces many challenges regarding the current state of transportation. There is a finite supply of fossil fuels, and that supply is becoming harder to find and extract which is creating more risk and costing more money. The gasoline engine dominates the vehicle market burning this dwindling resource at energy efficiency from 25% to 30% and the by product from current engine technologies are emitting carbon dioxide further polluting the air we breathe and warming the planet at an alarming rate. The need for alternative sources to power our vehicles is a critical step towards confronting these challenges now and into the future. There have been several gasoline electric hybrids technologies that have emerged along with very few fully electric vehicles. The scope of our project is to design a power electronics system which will modify an existing hydrogen fuel cell powered electric go-kart to drive the 1.12kW DC motor with a photovoltaic (PV) panel, ultracapacitors and a battery. Power electronics systems combining sources with disparate characteristics will be very useful in the transportation industry as future vehicles will likely be powered by multiple electrical sources. 2. Preliminary Requirements: Devices such as PV panels, ultracapacitors and batteries have complex chemical make ups which cause non-uniform current distributions, thereby causing difficulties in obtaining accurate source impedances. Gathering data in the form of Bode plots and transfer functions through Electrochemical Impedance Spectroscopy (EIS) measurements will aid in the design process of the power electronic topologies. Because the sources have varying power supply characteristics and the load has specific requirements for smooth and proper operation, the power electronics will be the critical link that converts and regulates these sources into a reliable output to the DC motor.
2 Based on the results on these analyses we will choose a multiple input power converter topology with necessary feedback control. We will then design a printed circuit board for the final implementation of the converter. The design will be tested to verify it can operate at the required power levels. Microcontroller software will be written to control converter operations. 3. System Diagram: Fig. 1: Preliminary System Diagram
3 4. Basic Limitations: The go-kart that our team has been provided has an existing power system that must remain operational and may be taken for demonstration during the timeline for this project. Our budget is $1000 (we are applying for additional funding through the office of undergraduate research). Computer programing is a common weakness amongst our team so extra time, effort and teamwork will go toward resolving this issue. Equipment available in the ITE labs is inadequate for this project s power needs. The photovoltaic panel s power output is dependent on weather conditions. Our power converter must be versatile to account for this. Learn proper operation of frequency response analyzer (FRA) for EIS testing. 5. Other Data: Maximum Power Point Tracking (MPPT) is a method by which a desirable power output from a photovoltaic device is maintained by manipulating the I-V curve through the use of control logic in the power converter. If possible, this method will be implemented in our power converter design. The construction of frames to attach and protect the PV panel, ultracapacitors and PCB is also required. 6. Questions: What component power ratings will be required to avoid component failure? What role will the PV panel play in the design: a trickle charge for the battery our a more direct role in powering the motor? Is regenerative braking an option that is worth incorporating into the system?
4 How much thermal dissipation will result from our design and what cooling system will be required to mitigate this? Will the heat affect component operation? Will the footprint of the power converter and the additional sources fit onto the existing kart structure? Due to the large amount of power required, what degree of electrical isolation is required? What level of power efficiency can be achieved?