MATLAB Simulation of Five Level Hybrid Multilevel Inverter | PWM vs Nearest Level Modulation

Summary

Key Points

• The five-level multi-level inverter topology consists of a single H-bridge, a single bidirectional switch, and two voltage sources. 0:26
• This inverter is capable of generating five distinct output voltage levels: VDC, VDC/2, 0, -VDC/2, and -VDC. 0:39
• Specific switch combinations, such as S1 and S2 for VDC or SA and S2 for VDC/2, are required to achieve each desired output voltage level. 0:39
• Zero voltage is generated by short-circuiting the load through specific switch pairs like S2 and S4 or S1 and S3. 1:50
• The control of the inverter's switches is primarily managed using two techniques: Nearest Level Modulation (NLM) and Pulse Width Modulation (PWM). 2:59
• Nearest Level Modulation (NLM) operates by comparing a sinusoidal waveform against several constant voltage levels to determine the appropriate switching pulses. 3:36
• Switching between NLM and PWM techniques results in observable differences in the inverter's output voltage waveform and current behavior. 3:36
• Pulse Width Modulation (PWM) involves comparing a sinusoidal modulating signal with a triangular carrier waveform to generate the necessary control pulses. 5:45
• The modulation index in PWM directly influences the number of output voltage levels and the magnitude of the inverter's output current. 7:03
• The video demonstrates the implementation of both NLM and PWM techniques in MATLAB, showcasing how changes in the modulation index affect the inverter's output characteristics. 8:38