Rotor Flux-Oriented Control of Induction Motor With Synchronized Sinusoidal PWM for Traction Application.

This paper proposes a vector-controlled squirrel cage induction motor drive with synchronized sinusoidal pulse width modulation (PWM) for traction applications. In traction applications, switching loss in insulated-gate bipolar transistors is very important, and hence, a switching frequency of few hundred hertz is used in these devices. A triangular carrier comparison-based synchronized sinusoidal PWM for medium-voltage inverters with low switching frequency (less than 500 Hz) is proposed in this paper. To have very good dynamic behavior of the synchronization scheme, the triangular carrier is generated from the instantaneous voltage references in a phase-locked manner. A synchronous carrier-based overmodulation scheme that ensures linearity between the reference voltage and the fundamental motor terminal voltage is also proposed. An inverse gain-based linearization method is used to match the reference and inverter output voltage fundamental. This overmodulation strategy fails at the zone of high values of modulation index and a reference modification approach is used in that zone. The proposed PWM and overmodulation schemes integrate methods of field weakening and harmonic current estimation available in the literature and propose a consolidated scheme, which ensures good dynamic response with wide speed variation for rotor flux-oriented induction motor drive. The scheme is experimentally verified and the results are presented. [ABSTRACT FROM AUTHOR]