Reduction of EMI with chaotic space vector modulation in direct torque control

In this paper a study is presented about the reduction of electromagnetic interference (EMI) in Direct Torque Control (DTC) method by the means of chaotic space vector modulation. Space Vector Modulated Direct Torque Control (SV-DTC) is a method developed to reduce current and moment fluctuations which stem from the hysteresis controllers used in classical DTC method. The switching frequency amplitude was changed chaotically in a Space Vector Modulated Direct Torque Control (FFSV-DTC) having a Fixed switching frequency, and Chaotic Space Vector Modulated Direct Torque Control (CAFSV-DTC) method having chaotic amplitude modulated switching frequency was obtained. CAFSV-DTC method was suggested to reduce EMI, acoustic noise and current harmonics which occur in FFSV- DTC method. For this purpose, the proposed CAFSV-DTC method, using a Permanent Magnet Synchronous Motor (PMSM) drive, is compared to Random Amplitude Frequency method (RSV-DTC) and FFSV-DTC. Simulation results indicate that the proposed method yields better results.