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Dual Multilevel Inverter Topology with Reduced Switch Count and Small DC-link Capacitor

Tech ID:
Principal Investigator:
Jinyeong Moon
Licensing Manager:

A multilevel inverter topology that provides multilevel operation without a neutral point connection. With no split dc-link capacitors, the neutral point balancing issue is completely eliminated. Instead, the neutral points of the phase-legs are interconnected through a single bidirectional switch. This topology reduces the required number of switches for dual inverter operations. All critical benefits of multilevel operation (e.g., low current total harmonic distortion, low switching loss, low common-mode electromagnetic interference noise, and low motor iron loss) are intact. The topology also offers a reduction in the dc-link capacitance up to 90%. Compared to a dual 2-level inverter, the invention with the same capacitance produces 50% less stress in the capacitor current and 50% less ripple in the capacitor voltage due to the multilevel operation without neutral point connections. The invention enables the same level of ripple performance with only 46% of the capacitance required in the dual 2-level topology leading significant cost and volume reductions.