Application aspects and design considerations for twelve and twenty-four pulse rectifiers in elevator drive systems /
rectifier schemes have been shown to be effective
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1998.
|
| Subjects: |
| Summary: | rectifier schemes have been shown to be effective methods for reducing line current harmonics. However, when employing these schemes in conjunction with elevator drive systems, several application aspects and design considerations such as load changes, input voltage unbalance and pre- existing voltage distortion, voltage sags and leakage impedance must be considered. In industrial systems where nonlinear loads are used, it is not uncommon to measure 1% to 3% voltage unbalance and/or 2.5% pre-existing sib and '7th harmonic voltage distortion. Voltage unbalanced of these magnitudes can cause a significant increase in the input current harmonic level, which can lead to an overheated transformer, blown fuses and component failure. The presence of pre-existing voltage distortion and large amounts of leakage impedance can substantially alter the DC output voltage of the rectifier bridges causing a mismatch in sharing capability and degradation in the performance of the proposed rectifier schemes. In addition, load changes on adjustable speed drives (ASD's) can increase the harmonic level of the input current. This thesis examines several of these aspects via analysis, simulation and experimentation. In order to mitigate these effects and ensure proper operation of the twelve and twenty-four pulse systems this thesis proposes a variety of corrective measures. |
|---|---|
| Item Description: | "Major subject: Electrical Engineering". Vita. |
| Physical Description: | xi, 99 leaves : illustrations ; 28 cm. Issued also on microfiche from Lange Micrographics. |
| Bibliography: | Includes bibliographical references: pages 97-98. |