1. Torque Ripple Minimization in Neutral-Point-Clamped Three-Level Inverter Fed Induction Motor Drives Operated at Low-Switching-Frequency.
- Author
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Tripathi, Avanish and Narayanan, G.
- Subjects
- *
INDUCTION motors , *MOTOR drives (Electric motors) , *PULSE width modulation transformers , *PULSE width modulation , *TORQUE - Abstract
Neutral-point-clamped (NPC) multilevel inverter fed high power drives operating at low switching frequency are prone to low-order torque pulsations. For a case of N switching angles per quarter, apart from maintaining the fundamental component, (N-1) voltage harmonics can be eliminated. Consequently, \fracN-12 or lower number of torque harmonics could be eliminated. This paper proposes an optimal pulse-width modulation (PWM), which minimizes the combined root mean square (RMS) value (\tau RMS ) of torque harmonics of order lower than $6N$ at any modulation index (M$) for an induction motor drive fed from an NPC three-level inverter. This paper considers cases of two, three, and four switching angles per quarter cycle of the pole voltage. Compared with synchronized sine-triangle PWM and selective harmonic elimination (SHE) PWM, the proposed PWM reduces the first (N-1$ ) torque harmonics (i.e., \tau _6 ) over a wide speed range. Simulation and experimental results are presented on a 3.7-kW open-loop constant volts-per-Hertz induction motor drive. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
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