PROJECT TITLE: CASCADED MULTILEVEL INVERTER EMPLOYING NEAREST LEVEL MODULATION (NLM) AND CONVENTIONAL MULTICARRIER PWM SWITCHING TECHNIQUE
Since the start of this semester till week 5, I have progressed in my Final Year Project-2 by acquiring the vital electrical components for hardware building such as capacitor, resistor, diode, mosfet, gate driver chip and others. Most of these components were bought online in a website called "element14". The rest of the components were bought from electronic shops in Taman Universiti, Johor.
These components are:
- Gate Driver IR2110 (4)
- Ceramic Capacitor 0.1uF (8)
- Electrolytic Capacitor 22uF (4)
- MOSFET IRF60B217 (8)
- Ceramic Cement Resistor 10W 100Ohm (1)
- Diode 1N5817 (4)
Another progress that I have made till week 5 was building the gate driver circuit and testing the circuit by using oscilloscope. Gate drive circuit is needed in this project in order to drive the MOSFET of the inverter circuit by increasing the voltage of the pulse signals generated by Arduino Uno from 5V to 15V to meet the range of operational voltage of the MOSFET. The schematic design of the gate driver circuit can be observed below:
Figure 1: Schematic design of gate drive IR2110
Figure 2: Gate Driver Circuit set up.
Figure 3: Pulses Generated from the circuit.
Due to the Covid-19 pandemic, I have to change my FYP project from hardware to software. The title that was chosen for my new FYP project is "Cascaded Multilevel Inverter Employing Nearest Level Modulation (NLM) and Multicarrier PWM Switching Technique". The project is simply design both control circuit of NLM and Multicarrier PWM to operate 5-level Inverter (H-Bridge). This project also want to emphasize the comparison between the low switching frequency technique which is NLM and high switching frequency technique which is PWM on multilevel inverter.
Project Workflow
The workflow of the project can be described as follows:
- Literature review.
- Power circuit simulation.
- Control circuit NLM simulation.
- Report Writing (FYP-1).
- FYP-1 Seminar.
- Control circuit Multicarrier PWM build up.
- Record data comparison.
- Result analysis.
- Report & Journal (FYP-2).
- FYP-2 Seminar.
FYP-2 Experiment Procedure
Control Circuit Multicarrier PWM Design (Simulink)
- Set up the sine wave generator with 50Hz frequency.
- Set up the triangular wave generator with 2000Hz frequency.
- Obtain the in phase triangular carrier using equation block in Simulink based on Figure 4.
- Compare both wave to obtain the PWM signals based on Figure 5.
- Assign each signals to correct switches of 5-level inverter power circuit.
Figure 4: In Phase Triangular Carrier Wave
Figure 5: Comparison between sine wave and triangular carrier wave
Objective of the Project
The main goals of the project are:
- To obtain a functional cascaded 5 level inverter employing Nearest Level Modulation (NLM) and conventional Multicarrier PWM switching technique.
- Manage to implement switching techniques using programming or MATLAB auto coding technique.
- To compare low switching frequency technique, NLM and high switching frequency technique, Multicarrier PWM on multilevel inverter.
The objective of the project can be divided into FYP-1 and FYP-2.
FYP-1
- Manage to design and simulate the power circuit Cascaded 5-Level inverter.
- Manage to design the Nearest Level Modulation (NLM) control circuit.
- Manage to generate switching pulses employing Nearest Level Modulation (NLM) switching technique.
FYP-2
- Manage to design the Multicarrier PWM control circuit.
- Manage to obtain data comparison and analysis between Nearest Level Modulation (NLM) and Multicarrier PWM switching technique.
FYP-2 Data Comparison
Some comparison of NLM and Multicarrier PWM in general will include:
- The complexity of control circuit for both switching techniques.
- The output waveform of inverter employing each technique.
- The frequency spectrum of the output waveform of inverter.
- The obtained THD employing each switching technique.
- The application of both switching techniques.