In this paper a low order harmonic elimination technique for an open-end winding induction motor drive is proposed. For the present open-end winding drive, the induction motor is fed from two 2-level inverters with different isolated d.c.-link voltages of ratio equal to 1:0.366. With such a scheme it is found that all the 5th and 7th order (6n +/- 1, where n = 1,3,5,7 etc.) harmonics are absent in the motor phase voltage. The third harmonic order currents are eliminated from the motor by using isolated d.c.-link supply for the two inverters. Once the 5th and 7th order harmonics are eliminated, the next higher order harmonics present in the motor phase voltages are 11th, 13th, 23th, 25th, etc. (6n +/- 1, n = 2, 4, 6 etc.). The proposed scheme is implemented for v/f contreol by using triangular carrier wave and appropriate modulating waves for each inverter. With the proposed modulating waves for each inverter a smooth transition to the over-modulation region is also achievable from the present open-end winding IM drive.
| Filename: | EPE Journal - 12-4 - 4 - Paper Mohapatra |
| Filesize: | 1.224 MB |
