Minimum Pulse Width Adjustment in Duties of SVPWM Technique for Synchronous Motor Drives Using a 3 Level NPC Inverter

The following paper presents the analysis of the dynamics of the Synchronous Motor Drives (SMD) operated by the three level Neutral Point Clamped (NPC) inverter using the modified space vector modulation technique. The theoretical aspect of any PWM technique does not includes the time delay, rise time and fall time of the switching device involved in the process thus it fails to meet the minimum pulse width requirement of the switching device which is the minimum time required to produce the switching transition from one state to the other state i.e. ON to OFF and OFF to ON states. In Space Vector Pulse Width Modulation (SVPWM) technique as the dwelling time of each space vector can be calculated and the switches involved in the generation of that space vector can also be defined. Any switch whose duty time does not meets the minimum transitional requirement, a correction factor can be introduced in the duty of that switch to produce a successful transition from any state. This paper we introduce the modified SVPWM along with the basics of SVPWM to meet the minimum switching criterion, the application of this technique can be generalized to any drive or converter with solid state switches, here this technique is applied to the synchronous motor drives for the dynamics improvement.