Download Product Life Cycle Report:

Product Life Cycle Report:
1. Introduction
1.1 Hardware Components and General Interface Design
In order to transfer power from the Avista fuel cell to the analog model power system, this
interface design uses four main components, not including the fuel cell. The DC to DC converter
regulates and steps up the DC output voltage from the fuel cell. This regulated voltage is fed
through a power inverter to create a three phase AC signal at 60Hz. This three phase signal,
which contains third harmonics from the switching of the inverter, is filtered by a delta to wye
transformer. This transformer also steps up the AC voltage to an appropriate magnitude,
matched with the AMPS voltage. The fourth component in the interface design is the zero
detection circuitry. This circuitry is used to determine the positions and timings of the three
voltage phases on the AMPS.
1.2 Power Flow Control
The DSP used to operate and control the power inverter has been programmed to accept signals
from the zero-detection circuitry. The DSP uses these signals to adjust the voltage phase such
that the signal from the inverter can be synchronized with the voltage signals on the AMPS.
Once synchronized, the phase angle is adjusted to control the power flow from the fuel cell to the
AMPS, completing the interface process.
2. Design
2.1 Choosing the Appropriate Hardware Components
The fuel cell used in this design is capable of reliably providing 100 Watts of power. In order to
provide a certain level of device safety and upgradeability, the DC to DC converter and AC
inverter were chosen to be able to transfer 200 Watts. This also ensures that the current ratings
on the devices won’t be exceeded due to reactive power transferred through the interface due to
differing voltage magnitudes at the output of the transformer and the AMPS. The transformer,
obtained from the UI ECE department, is rated at 8.5kVA and was chosen because of its
availability in the lab. The zero-detection circuitry was built from scratch to meet this system’s
unique specifications. It utilizes a series of logic gates to output a series of pulses that can be
interpreted by the DSP to determine the inverter switching timing.
2.2 Software Programming and System Control
In order to reprogram the DSP to adjust the inverter output voltage and phase, it had to be
reprogrammed. The reprogramming process involved analyzing the current programming,
modifying it to adjust the voltage magnitude, and adding additional code to accept the input from
the zero-detection circuitry. The software used to accomplish this task was the ***TI-blah.***
2.3 Hardware and Software Costs
Once appropriate components were chosen for this design, the DC to DC converter, the inverter,
and the components used to create the zero-detection circuitry were all purchased with funding
from the ECE Department and the ***GRANT***. The software and J-tag emulator used to
program the DSP were donated by TI. The transformer and inductor bank are on loan from the
ECE department, and will serve as removable, standalone devices that will be easy to connect
and disconnect. These items were provided at no cost.