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Sideband torque ripple in direct drive permanent magnet wind power generator system

The electromagnetic torque ripple generated in the permanent magnet synchronous machine (PMSM), also called sideband torque ripple, due to space vector pulse-width modulation (SVPWM) excitation, is analytically investigated. The main sideband torque ripple components of the PMSM driven by a SVPWM voltage source inverter in a wind power generation system are first derived from the corresponding sideband current harmonics. Then the first and second carrier frequency sideband torque ripple components in a 2MW direct drive PMSM wind power generator with three common control schemes of id=0 vector control, maximum torque per ampere (MTPA) vector control and direct torque control (DTC) are studied in details. Finally, the results from FEA based co-simulations are employed to confirm the validity of the analytical method.