A Harmonic Suppression Scheme for Full Speed Range of a Two-Level Inverter Fed Induction Motor Drive Using Switched Capacitive Filter

This paper proposes a novel harmonic suppression scheme for two-level inverter fed three-terminal induction motor drives using switched capacitive filter. Capacitor fed H-bridges used as filters are cascaded to conventional two-level inverter to eliminate fifth- and seventh-order harmonics for the full modulation range including a six-step operation. For the first time, two-level dodecagonal voltage space vector is implemented with single dc supply for three-terminal induction motor drive. Enabling the switched capacitive filtering at low-voltage domain and shifting the high frequency switching to the switched capacitive filter is shown. A uniform pulse width modulation technique is shown which charges and maintains the capacitor voltages while eliminating the fifth- and seventh-order harmonics for the full speed range.