Impact of Sine-Wave LC filter on Two-Level PWM VSI fed IM drive considering the long leads

When the inverter output pulse travels through the long leads, voltage reflection and damped high-frequency ringing take place at the motor terminals. The long leads and short rise time of inverter output voltage pulses result in degradation of motor insulation and may cause insulation breakdown in the long run. This paper deals with the technique to suppress the high dv/dt and to mitigate overvoltage at motor terminals due to voltage reflection using a sine-wave LC filter. The speed control of PWM VSI fed Induction Motor (IM) is implemented using DSP TMS320F28335. The sine-wave LC filter is designed and tested below the rated frequency. The sine-wave filter used in this paper provides numerous other advantages such as improvement in efficiency, reduction of torque pulsation, etc. The analysis has been done in MATLAB/Simulink and the same has been verified through the experimental results as well.