PWM Control Methods Based on Mathematical Equations for Z-Source Inverters

< p>In power converters, the total harmonic distortion (THD) can be decreased by using two strategies which are filtering and controlling methods. The filtering strategy is indeed costly because of using hardware devices (such as capacitor and inductor). A suitable strategy to control the modern power converters without using the hardware devices is the pulse width modulation (PWM) technique. In this paper, three new PWM control methods based on mathematical equations for various Z-source inverters (ZSIs) are proposed. Controlling the duty cycles of switches is the basic idea of these methods to control the output voltage. The proposed control methods are analyzed under the circumstances of constant input and balanced output voltage (CIBOV) and ripple input and balanced output voltage (RIBOV). The advantages of proposed methods are control of voltage, current and harmonic distortion. Other advantages of these methods are lower value for THD and elimination of low-order harmonics. The correctness operation of the proposed PWM techniques is proved by using the simulation results.

Keywords:

Pulse width modulation (PWM) , Quasi-Z-source inverter (qZSI) , Shoot-through (ST) state , Total harmonic distortion (THD)