Simplified Analytical Modeling of Reflected Wave Transients in Cable-Connected VSI-Based Motor Drives With Output Reactor

This letter proposes a simplified lumped analytical model to investigate reflected wave phenomenon (RWP) in a two-level voltage source inverter-based motor drive with an output reactor. RWP causes motor side overvoltage and drive side overcurrent. The output reactor at the drive side is a preferred RWP mitigation approach for its simplicity. However, existing RWP modeling approaches, for reactor design purposes, rely on complex cable and motor circuit models, requiring time-consuming simulations or are oversimplified, neglecting motor impedance and drive's output slew rate
$\text{d}v/\text{d}t$
. To address this, the proposed model incorporates a condensed motor model and a ramp edge source for the drive output. It is solved to obtain closed-form expressions for estimating the slew rate of overvoltage and overcurrent transients and their respective peak values. Finally, the derived expressions are validated through double pulse tests on a silicon carbide-based hardware prototype for different cable lengths and reactor values.