Carrier-based sinusoidal pulse-width modulation techniques for flying capacitor modular multi-level cascaded...

Area of Science:

• Electrical Engineering
• Power Electronics
• Control Systems

Background:

• Modular multilevel cascaded converters (MMCC) are crucial for high-voltage applications.
• Conventional carrier-based PWM techniques like PD-PWM and PS-PWM are standard for MMCCs with H-bridge sub-modules.
• A variant, the MMCC five-level flying capacitor converter, introduces challenges in voltage balancing.

Purpose of the Study:

• To evaluate conventional PWM techniques (PD-PWM, PS-PWM) on a five-level flying capacitor MMCC.
• To introduce and assess two novel swapped carrier PWM techniques for this specific MMCC.
• To compare the performance of new and conventional PWM schemes.

Main Methods:

• Implementation and simulation of phase disposed PWM (PD-PWM) and phase shifted PWM (PS-PWM).
• Development and implementation of two novel swapped carrier PWM techniques.
• Comparative analysis based on voltage waveform quality, flying capacitor voltage balancing, power loss, and switch utilization.

Main Results:

• The proposed swapped carrier PWM techniques demonstrate superior performance in reducing switching and conduction power losses.
• Novel PWM schemes achieve comparable voltage waveform performance to PS-PWM.
• Effective natural flying capacitor voltage balancing is maintained by the new PWM techniques.

Conclusions:

• Swapped carrier PWM techniques offer an improved control strategy for MMCCs with flying capacitor sub-modules.
• These novel techniques provide a better balance between power loss reduction and operational performance.
• The findings suggest a promising alternative for advanced MMCC control applications.