A novel delta-sigma modulated space vector modulation scheme using scalar delta-sigma modulators

With advances of semiconductor switching power devices, operating frequency and power capacity of switching mode power converters are much improved. In these converters, pulse width modulation (PWM) technique is widely used, but by using this control scheme, large peak noise spectra appear with odd interval of carrier frequency. In AC motor drive system, space vector control scheme is used for high performance control system. But this control scheme is relatively complex, high performance processor such as DSP is needed for pulse pattern generation. In this paper, the authors propose a novel delta-sigma modulated space vector modulation scheme using scalar delta-sigma modulators. Proposed system configuration is very simple because only 2 scalar delta-sigma modulators are used. Furthermore, by the spread spectrum nature of delta-sigma modulator, noise level within unnecessary band is much reduced. As a results, simple configuration and low noise AC motor drive system are realized. From the simulation results, the authors confirmed that proposed system operates effectively as vector control system and noise level is much reduced.