Motor Overvoltage Mitigation Using SiC-Based Zero-Voltage Switching Inverter
Suleman Yunus, Wenlong Ming, Carlos E. Ugalde‐Loo
Abstract
The motor overvoltage phenomenon is an issue that may arise from the high voltage slew rates ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathrm{d}v/\mathrm{d}t$</tex-math></inline-formula> ) of silicon carbide <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s in cable-fed drives. This can lead to substantial strain on cable and motor insulation, resulting from partial discharges and uneven voltage distribution. In line with this, this article presents a novel method to select inductor and capacitor parameters for a zero-voltage switching (ZVS) inverter to mitigate motor overvoltage. The ZVS inverter employs only one additional active switch on the positive dc terminal compared with two-level inverters. This prevents the need for bulky <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCR</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> passive filters or multilevel inverters in conventional solutions, which may lead to increased volume and losses. The presented approach suppresses overvoltage oscillations by profiling the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathrm{d}v/\mathrm{d}t$</tex-math></inline-formula> of both resonant and natural commutations while minimizing the switching losses. A comparison with alternative techniques for mitigating motor overvoltage was conducted to demonstrate the method's efficacy, including two-level passive filter strategies and three-level inverters. The presented technique was validated through simulations in PLECS and MATLAB/Simulink, demonstrating a 1% increase in efficiency and a 30% reduction in volume. Furthermore, the method was experimentally verified, showing the measured overvoltage being reduced from 2 to 1.06 per unit.