An Advanced Modulation Technique for Power Quality Improvement in 12-Pulse Rectifier-Inverter Fed Induction Motor Drive

In 12-pulse diode bridge rectifier (DBR)- inverter fed induction motor drive (IMD), how to improve the ability of minimizing line current harmonic is always a hot issue. The basic 12-pulse DBR used in IMD does not satisfy the IEEE-519 standard. Line current harmonics due to DBR for IMD is strongly influenced by the pulse width modulation (PWM) method employed in inverter switching. Various PWM techniques are known to mitigate the total harmonic distortion (THD) of line current of IMD. This paper aims at further mitigation in line current THD by employing an advanced PWM techniques, which utilize multiple harmonic injection in the modulating signal trapezoidal PWM (TRPWM) to form a new modulating signal. The proposed modulation technique offers 4.07% line current THD which complies IEEE-519 standard. The proposed modulation technique is analyzed, simulated in MATLAB/Simulink environment for a 12-pulse DBR, 2-level inverter fed IMD and the simulation results are presented, which confirms the reduction of line current THD, and optimum torque ripple and thereby improving other power quality parameters of IMD under large load variations.