High Power Multilevel DC-DC Converter

Student: Janne Nilsson

Supervisor: Geoffrey Walker

Category: Engineering Thesis Project - Electronics

Modern vehicle designs are incorporating an increasing level of electrical loads. Many advantages of running traditional mechanical loads from the electrical system are being realised, however, the introduction of these ‘extra’ loads has led to unpractical cable sizes and increased losses due to the large currents required.

To solve this power crisis for the future, a new 42-volt standard has been agreed upon, which will allow the addition of higher power loads. A 42-volt system is however not practical for auxiliary loads such as lights, radios, instrumentation, etc which brings about the need for a dual voltage system. Hence, a DC/DC converter is required to step down the 42-volt supply to 14 volts.

The converter is to have at least a 770W power rating with an output current handling capability of 55A. It is also desirable for the converter to be bi-directional (in case a dual battery system is used) and have an overall efficiency of greater than 90%.

The topic of this thesis is to design and build a prototype of such a converter. These goals are obtained through the use of switch-mode technology incorporated in a multilevel, modular design, comprised of parallel power converter modules. This approach offers improved efficiency, lower cost and increased flexibility, which makes it suitable for its intended application.

Thesis Document (PDF)

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