A 24-Sided Voltage Space Vector Based IM Drive with Low-Order Harmonic Elimination for the Full Speed Range

This paper proposes an inverter topology to generate a 24-sided polygonal voltage space vector structure for variable speed drives using a single dc source. The topology consists of a two-level inverter cascaded with two low-voltage floating capacitor-fed H-bridge cells. The 24-sided structure eliminates harmonics up to and including seventeenth and nineteenth orders from phase voltage output resulting in a smooth torque profile over the entire speed range. This structure also enhances the linear modulation range to 99.42% of the base speed. A reduced switching sequence based pulse width modulation technique achieves minimum pole voltage transitions for the two-level inverter, thereby controlling switching losses. The lower order harmonics are eliminated by switching action of low-voltage H-bridge cells. Experimental results, simulation studies on inverter losses, and harmonic performance validate the effectiveness of proposed drive scheme.