Experimental and simulation studies on dead-time effect and its compensation on LV and MV drive

This paper presents the effect of dead-time and its compensation in a voltage source inverter for a scalar controlled induction motor drive at low speeds on light load condition. It is observed that the oscillations in the stator current under light-load conditions in a practical low voltage 690V, 875-kW and medium voltage 6.6kV, 1.8 MW 3-level inverter fed-induction motor drives is due to dead-time of the inverter. The paper presents the simulation results of dead-time effect and its compensation method on 1.8 MW MV 3-level drive. This paper also shows the experimental results of dead-time effect and a simple dead-time compensation method which mitigates the oscillations in stator current significantly on a low voltage 875 kW induction motor drive. It also presents the results when the drive is operated in sensorless vector control method, in which the compensation is done by the control loops itself.