DSP based implementation of a new V/F control scheme based on non-conventional space vector modulation for better dynamic response, smooth transition to overmodulation region and operation without line voltage sensors

A new V/F control scheme for electric drives has been developed and implemented on a TMS320C50-based DSP platform based on a nonconventional SVM scheme. The choice of the unique switching state for this stator flux oriented controller is based on the stator flux error, thereby controlling the flux to be constant and changing the torque in an optimum fashion. The calculation of actual machine flux is done using the bus voltage and the switching pattern, thereby eliminating the need for line voltage sensing. Due to the control of the inverter, based on actual machine flux, the switching loss is low compared to constant frequency PWM and the unique selection of switching states makes the transition to the overmodulation region smooth. The V/F based system was implemented in frequency, torque and speed mode and the dynamic response was found to be good.