Design Of DC-DC Converter Research Articles

A miniature transformer/dc-dc converter for implantable medical devices

This paper presents a new technique for the design of a miniature dc-dc converter used in energy producing implantable devices such as defibrillators and advanced pacemakers. This converter is inserted in such a device and is used to boost the voltage from a low voltage implanted battery to high voltage energy storage capacitors in a short period of time. The stored energy is then delivered, when needed, through an energy delivery circuit in order to stimulate or defibrillate the heart. The converter takes the form of a flyback topology which includes a miniature transformer and a specialized control circuit. The transformer was designed using a new numerical synthesis method which utilizes finite elements and dynamic programming for predicting the geometries of the transformer’s magnetic circuit. The final transformer design satisfied the performance criteria and provided means for selecting the converter components. The obtained performance results for the transformer and the dc-dc converter were in excellent agreement with laboratory performance tests.

Design Optimization for a Half-Bridge DC-DC Converter

A nonlinear programming technique using the penalty function method is employed for the minimum weight design of a halfbridge dc-dc buck power converter. The cost-effective computeraided approach provides a minimum weight design down to the details of the component level which concurrently meets all power circuit performance requirements. Important design insights and guidelines are obtained to readily assess 1) the tradeoffs between weight and loss as the switching frequency is increased, 2) the optimum operating frequency range over which the total weight/loss is minimized, 3) the impact of device characteristics on the total weight and loss profile.

A Kilowatt Rotary Power Transformer

Many future satellite configurations will require the transfer of signals and power across rotating interfaces. Satellite systems are particularly cost effective for both commercial and military communications applications if their useful lifetime can be demonstrated to be greater than five years. The rotary transformer has the desireable characteristics of high reliability and low noise which qualify it as a potential replacement for slip rings. This paper describes the development of a rotary transformer for typical spacecraft applications. The transformer is built in modular sections, each capable of transferring 500 watts across a gap at efficiencies greater than 88 percent, dc to dc. The design effort included a study of pertinent electrical characteristics required for typical spacecraft configurations, electrical design and analyses of the overall dc-dc converter, mechanical design of the transformer cores and their assembly, and a study of transformer core and winding characteristics. Breadboard test results have demonstrated the desired level of efficiency, satisfactory operation over temperature, and satisfactory electrical characteristics.