Abstract
This paper deals with a novel natural sampled pulse width modulation strategy for three phase Z-source inverter through carrier modification. The proposed sine carrier method, which uses the conventional sinusoidal reference signal and a sine carrier, has a better harmonic spectrum and a higher fundamental component compared to the conventional triangular carrier based PWM. The sine carrier PWM enhances the fundamental output voltage while keeping the total harmonic distortion lower without involving changes in device switching loss. The detailed comparison of harmonic content and fundamental component of the sine carrier PWM output with the results obtained for the conventional PWM is also presented. Microcontroller is chosen for the hardware implementation of the switching strategy, mainly due to its high computation speed which can ensure the accuracy of the instants that gating signals are generated.
Highlights
The active states have to be kept unchanged to maintain the output voltage waveform, and the traditional zero states can be replaced partially or entirely by the shoot through zero states depending on how much voltage boost is needed
The available shoot-through period is limited by the zero-state period that is determined by the modulation index
In this conventional simple boost control method, to achieve the high output voltage, it is required to increase the shoot through duty ratio, which can only be achieved with the reduction of modulation index
Summary
The Z-source inverter intentionally utilizes the shoot-through zero states to boost dc voltage and produce and output voltage greater than the original dc voltage. In the conventional simple boost control method, a triangular carrier was used to control the shoot-through duty ratio. In this case, the shoot-through time per switching cycle is constant, which means the boost factor is constant. The shoot-through time per switching cycle is constant, which means the boost factor is constant In this conventional triangular carrier PWM the shoot through duty ratio is given as. In this conventional simple boost control method, to achieve the high output voltage, it is required to increase the shoot through duty ratio, which can only be achieved with the reduction of modulation index. The sine carrier gives higher shoot through duty ratio without any pulse dropping at given modulation index while makes the dependency a little non linear
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call