| |
DIRECT SELF-CONTROL OF VSI-FED INDUCTION MOTOR DRIVES WITH REDUCED LINE CURRENT HARMONICS AND ACTIVE DAMPING OF SUBHARMONICS
| [View]
[Download]
|
| Author(s) |
A. M. Walczyna |
| Abstract |
Direct Self-Control (DSC) has become to be widely used in traction. For such drives low frequency pulsation of line current is a major problem because of the requirement of compatibility with the supply and signalling system. In case of DC traction inverter drives are often fed directly from a contact line. It is shown in the paper that the inverter high power drive fed directly from a DC contact line through a typical LC filter and controlled by the standard DSC method generates line current harmonics of values that exceed all acceptable European limits.
A new PWM, called "flux trajectory forming modulation", is proposed for DSC. It allows to eliminate all dominating low frequency line current harmonics in the entire drive speed band. In this way substantial reduction of the level of line current harmonics in comparison to standard DSC can be obtained without adding any active filter. The technique allows either to meet the severe limits for line current harmonics of some railway authorities or to substantially reduce the weight of an input filter of DSC controlled drives.
A disadvantage of DSC method is that it generates current subharmonics at the inverter output and input side. It is
shown that amplitude of drive input current subharmonics can be greater than amplitudes of other harmonics. In the paper sources of sub harmonics generated by the method are investigated. A new technique for active damping of these subharmonics is given and compared to the known solution of Janecke (16). The proposed techniques are illustrated by results of simulation of a high power drive. |
| Download |
| Filename: | Unnamed file |
| Filesize: | 639.6 KB |
|
| Type |
Members Only |
| Date |
Last modified 2018-04-12 by System |
| |
 |