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OPTIMAL VARIABLE-FREQUENCY TECHNIQUE FOR OPERATING DC-AC-DC CONVERTERS BASED ON MULTIPHASE TRANSFORMERS

IP.com Disclosure Number: IPCOM000243286D
Publication Date: 2015-Sep-18
Document File: 6 page(s) / 236K

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention proposes a technique to operate DC-AC-DC converters with optimal design. The technique includes a variable-frequency power regulation of the DC-AC-DC converters based on multiphase transformers and two inverters. According to the present technique such converters are operated close to optimal waveforms that minimize size of DC-link capacitors and affects cooling system. The transferred power is regulated by acting on the switching frequency only.

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OPTIMAL VARIABLE-FREQUENCY TECHNIQUE FOR OPERATING DC-AC-DC CONVERTERS BASED ON MULTIPHASE TRANSFORMERS

 

 

BRIEF ABSTRACT

The invention proposes a technique to operate DC-AC-DC converters with optimal design. The technique includes a variable-frequency power regulation of the DC-AC-DC converters based on multiphase transformers and two inverters. According to the present technique such converters are operated close to optimal waveforms that minimize size of DC-link capacitors and affects cooling system. The transferred power is regulated by acting on the switching frequency only.

KEYWORDS

Converters, inverters, transformers, optimal waveforms, DC-link, capacitors, current, voltage

DETAILED DESCRIPTION

Generally, multiphase intermediate AC conversion in DC-AC-DC converters allows greater power density of a transformer and a converter. Challenges exist with respect to design of an overall system that is power dense and not only for some subsystems. Achieving a single compact subsystem forces other components around to be oversized, serves limited purpose as there is lowering of power density of the whole system. Transformers operating with high harmonic content, high insulation levels and high frequencies are difficult to design. Parameters of such transformers are not adapted to simplify the design of inverters. Usually the transformer designer enjoys only little degree of freedom, especially for leakages inductances and rendering a transformer optimal for the overall converter remains a challenge.

A conventional technique includes control of average power in the converters by adjusting duty cycle and/or delay of the inverter phase voltages. However, the conventional technique requires power regulation by varying or modulating frequency. In contrast, the duty cycle and delay adjustments are utilized to reduce DC-link capacitors.

Another conventional technique includes an unlimited voltage static power converter, which includes an array of multi-level phase drivers consisting of a plurality of H-bridge power modules connected in series. Yet, another conventional technique includes a converter having transformer with primary and secondary windings each having oils in a series-series arrangement connected to primary and secondary sides.

However, the conventional technique utilizes waveform modulation for regulating the transferred power.

Therefore, there is a need for a technique to minimize size of DC-link capacitors without utilizing waveform modulation for regulating the transferred power.

The invention proposes a technique to operate DC-AC-DC converters with an optimal design. The technique includes a variable-frequency power regulation of the DC-AC-DC converters based on multiphase transformers and two inverters. The invention operates such converters close to optimal waveforms that minimizes size of DC-link capacitors and affects a cooling system. The transferred power is regulated by acting on the switching frequency only.  

The technique pr...