1. Space-Vector-Quantized Dithered Sigma–Delta Modulator for Reducing the Harmonic Noise in Multilevel Converters.
- Author
-
Jacob, Biji and Baiju, M. R.
- Subjects
- *
CONVERTERS (Electronics) , *ELECTROMAGNETIC devices , *DELTA-sigma modulation , *VOLTAGE-frequency converters , *HARMONIC distortion (Physics) , *VECTOR-space models (Information retrieval) - Abstract
Power converters using deterministic switching frequency schemes have switching noise concentrated at harmonic frequencies, resulting in enhanced electromagnetic emission. To suppress the harmonic spikes in three-phase multilevel voltage source converters, a digital control scheme based on dithered sigma–delta modulation (SDM) is proposed in this paper. Introducing a dithered sequence in an SDM varies the switching frequency randomly, resulting in the suppression of the spurious harmonic spikes in the output spectrum even with a regular control input. Although the switching frequency varies randomly, the minimum pulsewidth of the proposed scheme is the sampling time period, avoiding the minimum pulsewidth problem. Instead of a conventional scalar quantizer, the quantizer in the proposed dithered sigma–delta converter uses the principle of space vector quantization. The proposed scheme is experimentally verified on a constant $v/f$ open-loop induction motor drive for a three-level inverter realized by cascading two two-level inverters. The performance of the proposed scheme is compared with different pulsewidth modulation schemes in the entire modulation index, including the overmodulation region. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF