Development Of DC/DC Converters And EMC For Electric Vehicles

With the development of the Automobile Industry, internal-combustion engine faced the unprecedented challenge of environmental pollution, global warming and energy shortage. Fuel Cell Electric Vehicle (FCEV) becomes the new focus of Automobile Industry. Because of the special output character of the Fuel Cell, the output terminal should be connected to DC/DC Converter; So DC/DC converter is one of the most important parts of FCEV.At first, the principle and specialty of several traditional Buck/Boost converters is introduced. The advantages and disadvantages of these converters are analyzed and compared, according to the specialty of Fuel Cell and the Vehicle's demand for high performances, this dissertation indicates a new type Buck/Boost DC/DC converter Buck-Boost cascaded one. Then the control strategy and specialty of this converter is introduced, and operational principle is simulated and analyzed using the Matlab. And the simulation results prove that the control method is right.Secondly, the principle and application of bidirectional DC/DC converters is analyzed and researched. The advantages and disadvantages of these traditional converters including the isolation ones and non-isolation ones are analyzed and compared. Then a best topology is chosen for the FCEV use. According to its operational principle, the power unit and control software are designed, especially for the control strategy of transition process. After simulating these strateries, the better one is chosen. At last a 1kW bi-derectional DC/DC converter is built and the perfect result testifies the analysis above is right.Finally, this dissertation discusses in-depth the electromagnetic compatibility (EMC) for DC/DC converter and focuses on the main EMI sources, their causal mechanism and coupling approaches. Then the author puts emphasis on the according countermeasures of the annoying EMI issues.