PROJECT TITLE: CASCADED MULTILEVEL INVERTER EMPLOYING NEAREST LEVEL MODULATION (NLM) SWITCHING BASED ON ARDUINO
Since the last five weeks, I managed to conduct three preliminary experiments which is designing Nearest Level Modulation (NLM) control circuit, simulating cascaded H-bridge 5-level inverter employing NLM control circuit and generating pulse by using Arduino UNO. I managed to achieve NLM switching technique by comparing the reference sine wave with DC constants in control circuit. This comparison can generate pulses that can be used for switching of the inverter. The control circuit then uploaded to Arduino UNO by using Arduino Support Package in MATLAB to generate switching pulses. The pulses generated were tested and verified using oscilloscope and multimeter.
Preliminary Experiments
I divided my FYP-1 preliminary experiments into three tasks which are:
1. Designing Nearest Level Modulation (NLM) control circuit using MATLAB auto coding.
Figure 1: NLM Control Circuit Model.
2. Simulating the cascaded 5-level inverter power circuit in MATLAB/Simulink employing NLM control circuit.
Figure 2: Cascaded 5-level inverter using NLM switching.
3. Generating digital pulse by using Arduino Uno.
- Uploading the control circuit to the Arduino Uno using Arduino Support Package in MATLAB.
- Testing and verifying the pulse signal using oscilloscope and multimeter.
Figure 3: Pulse generated by Arduino Uno in oscilloscope.
Preliminary Results and Outcomes
1) NLM Control Circuit Design
Figure 4: Output pulse of NLM Control Circuit.
2) Power Circuit Simulation
Figure 5: Output waveform of 5-level Inverter.
Figure 6: Total Harmonic Distortion (THD) of the output waveform, 17.08% without filter.
3) Digital Pulse Generation
Figure 7: Pulse generated by Arduino Uno in oscilloscope.
Figure 8: Voltage amplitude of the pulse.
FYP-1 Outcomes
- Managed to obtain simulation result of cascaded 5-level inverter with 17.08% THD.
- Managed to design switching control circuit employing Nearest Level Modulation (NLM).
- Managed to generate switching pulses using Arduino Uno with amplitude of 4.26V suitable enough to connect with the gate driver soon to be done in FYP-2.