Publication Detail

Are Active Rectifiers Required?

James Kirtley, Mischa Steurer, Matthew Bosworth, Xing Liu Liu, Scott D. Sudhoff, Steve Pekarek, Saher Albatran, Chiranjeeevie Madvesh

This study investigated the issues in selecting the type of rectifier to be used in a ship system in which a substantial part (or all) of all generated electric power is converted to DC. The type and control methods for the AC/DC rectifier are known to have substantive impacts on both the generator and on the DC power system. Among the important features of the rectifier system are its behavior in the event of a fault on the DC side of the system, injection of time harmonic currents in both AC and DC sides of the system, and control of DC side voltage.

We considered the circuit morphology of a number of rectifier systems and the requirements for filtering of time harmonics generated by the rectifier circuits. Of particular interest was the impact on system generators and control of the electrical system in view of faults and pulsed loads. Among the most important issues are how well the generator/rectifier system can control system voltage, particularly in the presence of pulsed loads, and perhaps as important, how can system protection avoid damage in the presence of a serious fault, such as a short circuit.

Key Findings
1. Not all active rectifier systems can assist in fault protection, but some can.
2. Active rectifier systems do not appear to have a major impact on generator sizing.
3. Active rectifiers can produce more rapid response to load variation, but probably cannot provide sufficient response for large pulsed loads without energy storage.
4. Some types of rectifiers will have an impact on size and loss characteristics of passive components in filters to meet ship power quality standards.

The answer to the question that is the title of this study is thus not an unequivocal ‘yes’ or ‘no’. The answer for any given ship system will depend on specifics of that ship. This report describes some of the considerations that will go into the decision and points out some avenues of further research.

type: Technical reports

Parent Project

Project No.: 2014-ESRDC-04-LEV
Title: ESRDC - Designing and Powering the Future Fleet Additional Task 1.4.3 Concept Refinement

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