Instantaneous Induced Braking Energy Modeling and Disperse Inverter Voltage Vector Synthesis for Maximum Energy Recovery in IM-Based Drives

Abstract

This paper introduces a novel approach for recovering braking energy in induction motor drives, employing a specific inverter switching sequence. During braking, a phase deviation between the motor voltage and the synthesized inverter voltage is proposed to capture and redirect braking energy back into the DC circuit. To accomplish the phase deviation, in this work, an analytical model for the stator-induced voltage is developed as a function of rotor kinetic energy and magnetic field intensity. Using the developed model, the braking energy recovery characteristics are analyzed by varying the phase deviation (dispersed angles) between the stator-induced voltage and the inverter-synthesized voltage. The investigation by formulating an energy function reveals that the degree of phase deviation significantly impacts energy exchange between the motor and DC circuit during braking. The energy exchange characteristics suggest that energy recovery is possible only when the dispersed angle is more than 180°; thus, the dispersed angle variation between 180° to 360° is identified as an energy recovery region. The presented work identifies the sector where maximum energy recovery occurs within the energy recovery region. Finally, the analytical findings are validated experimentally by synthesizing various dispersed angles using the inverter, considering the instantaneous motor voltage vector positions as a reference. To recover the extracted braking energy, this work proposes a DC/DC converter-based energy recovery scheme, incorporating monitoring of the DC bus voltage to facilitate energy storage in a battery bank. The proposed method holds promise for enhancing energy utilization efficiency and improving the economic viability of industrial and electric vehicle (EV) drives.