EEL 6245/4241
Power Electronics Course Project
Objective
The main objective of this project is to analyze and simulate a system of power electronics. In topic 1,
system consists of DC to DC convertor and a three phase Dc to Ac invertor that to a grid. The project
aims to demonstrate the capability to design and simulate the converter and invertor, run steady-state
analysis, and perform Fourier analysis on the voltage and current waveforms on both the DC and AC
sides. Additionally, the project involves the implementation and simulation of control strategies for
bidirectional power flow between the DC source and the grid.
Introduction
In modern power systems, the integration of renewable energy sources and the interconnection of
different power domains necessitate efficient conversion between different forms of electricity.
Converters play a critical role in these systems by ensuring the compatibility of the voltage, current, and
frequency characteristics of the power being transmitted or utilized. This report presents the design and
simulation of a single-phase DC-DC converter and a three-phase DC-AC invertor system. The system is
designed to interconnect a DC power source with the AC power grid, facilitating energy conversion with
high efficiency and controlled power flow.
Theoretical Background
DC-DC Converters
DC to DC converters are electronic circuits that convert direct current (DC) from one voltage level to
another. They are essential components in modern electronic devices, enabling the power management
necessary for many applications. For example, a boost converter steps up the voltage, while a buck
converter steps down the voltage. We use Boost convertor in this project.
DC-AC Converters
A DC to AC converter which is also known as inverter, changes DC input into alternating current (AC)
output. The inverter's output can be single-phase or three-phase, depending on the application. In this
project, a three-phase inverter connects the DC domain to the AC grid, enabling power exchange with
the grid.
Grid Interconnection
The AC side of the invertor is connected to the power grid, which operates at a standardized voltage and
frequency. In the United States, this is typically 208V at 60Hz. Interconnection with the grid requires
synchronization of the inverter output with the grid voltage and frequency.
Control Strategies for Power Flow
Controlling power flow in a converter system involves managing the direction and amount of power
transferred. In this project, two control strategies are implemented: one allowing power flow from the
grid to the DC source and another allowing power flow from the DC source to the grid. These strategies
are vital for applications like battery charging and renewable energy systems, where bidirectional power
flow is required.
Fourier Analysis
Fourier analysis decomposes the voltage and current waveforms into their constituent frequencies. This
is important in power electronics to assess the harmonic content and the quality of the power being
delivered. Harmonic distortions can lead to inefficiencies and disturbances in the power system.
Simulation of Topic 1
The system simulation in MATLAB/Simscape provides a platform to analyze the behavior of the power
electronics system under various conditions. It enables the visualization of voltage and current
waveforms and the performance of Fourier analysis to evaluate the quality of the power conversion.
Overall circuit:
DC to DC Convertor:
Invertor Controller:
Parameters Table of Topic 1:
Switching Frequency 10000 Hz
DC to Convertor Parameters
DC Input Voltage 400 V
DC Output Voltage 800V
Duty Cycle 50%
Inductor (L) 0.88mH
Capacitor © 2000μF
Resistor ® 40
Capacitor Filter 100 μF
Invertor Controller Parameters
Id 100 A
Iq 0A
Filter Inductance 1000μH
Filter capacitance 100μF
Proportional Gain 5
Integral Gain 5000
Grid Voltage 208 V (rms)
Grid Frequency 60 Hz
Results of Topic 1:
AC Current and Voltage Waveform:
DC to DC Convertor Voltage:
Current Waveform:
Fourier Series Analysis:
AC Voltage:
AC Current:
DC voltage:
DC current:
