A novel PWM scheme for a three-level voltage source inverter with GTO thyristors

This paper presents a new PWM scheme for a three-level GTO inverters based on space voltage vectors. By this PWM method, the harmonic components of the output voltage can be minimised by avoiding the minimum pulse width limitation problem of the GTO and voltage balancing of DC link capacitors can also be kept. The principle of the PWM method and the voltage vector selection procedure are described in detail. Computer simulation and experimental results verify that the proposed PWM control scheme is suitable for high power and high voltage three-level GTO inverters applied to induction motor drives.>