Voltage Control Technique for the Extension of DC-Link Voltage Utilization of Finite-Speed SPMSM Drives

This paper presents a new voltage control technique which extends dc-link voltage utilization for finite-speed surface-mounted permanent magnet synchronous motor drives. Therefore, significantly increasing the output power and torque under flux-weakening operation can be achieved. The switching period and summation of active switching times for inverter pulsewidth modulation control are used to modify the -axis current reference under the flux-weakening region such that the voltage trajectory of inverter output can be extended to move to the hexagon of the space vector modulation, thereby extending the utilization of dc-link voltage. Moreover, it will be shown that the proposed voltage control technique has some additional special features, such as not sensitive to motor parameter, no need of voltage and current feedback, and no need of lookup table. The presented method is realized by software and does not require additional hardware. Comparisons of experimental results will be presented for confirming the presented technique.