Supply voltage boosting using a floating capacitor bridge in a 3 level space vector modulated inverter system for an open-end winding induction motor drive

Abstract

Dual inverter fed open winding induction motor drives can be used to minimize the problem of flux weakening during higher speed applications. If a floating dc-link capacitor is used in the second inverter, it can provide voltage boosting to increase the motor voltage during higher speeds. This leads to the minimization of supply current during high speed operation along with the supply voltage regulation. Previous works have been done on dual 2-level inverters. In this paper, a controller is designed so as to adjust the capacitor voltage to maintain constant motor voltage along with a 3-level output from a space vector modulated dual inverter system during high speed operation. During low speed operation motor current charges the capacitor and the capacitor discharge is controlled so as to obtain the required motor voltage. Entire system is modeled and simulated in MATLAB and the results are verified.