Authors:-Venkata Anusha Ongolu, P.Syam kumar
Abstract:-This paper presents improvement of dynamic performance of permanent magnet synchronous machine using modular multilevel converter. This paper proposes a control strategy for the robust dynamic response of MMC even at zero output frequency employing leg offset voltage injection. The leg offset voltage for balancing the arm energy is produced by direct calculation without the circulating current control loop controller. Thanks to the highly dynamic leg offset voltage from direct calculation and not conventional circulating current controller, the dynamic performance of the MMC at low speeds has conspicuously improved. The AC machine has been driven from standstill to rated speed without excessive cell capacitor voltage ripples utilizing this proposed strategy. The simulation results verify that stable operation is guaranteed down to less than 2 % of the rated speed under 40% step load torque disturbance.