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Power converters using deterministic switching frequency schemes have switching noises concentrated at the 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 is proposed in this paper. Introducing a dithered sequence in the Sigma Delta Modulator varies switching frequency randomly, resulting in the suppression of the spurious harmonic spikes in output spectrum even with regular control input. Even though the switching frequency varies randomly, the minimum pulse width of the proposed scheme is the sampling time period, avoiding the minimum pulse width problem. Instead of conventional scalar quantizer, the quantizer in the proposed dithered sigma delta converter uses the principle of Space Vector Quantization. The proposed scheme is verified experimentally on constant v/f openloop induction motor drive for three-level inverter realized by cascading two two-level inverters. The performance of the proposed scheme is compared with different Pulse Width Modulation schemes in entire modulation index including overmodulation region. ). M. R. Baiju is with College of Engineering, Trivandrum. (mrbaiju@ieee.org).0278-0046 (c)