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Robust Control Applied to a Dc/Dc Step-Down Switching Regulator for 14/42v Hybrid Architectures
Published May 23, 2004 by Society of Automotive Engineers of Korea in South Korea
In the present paper the well-known DC/DC step-down switching regulator based on PWM techniques is used to supply 14V to the electrical and electronic systems of next-generation cars, which not only will have to perform under 42V technology, but also with many automotive electrical and electronic systems which have been designed to work under the soon-to-be obsolete 14V technology. It is predicted that the 42V technology will be implemented in higher-end luxury cars and that the full implementation across all car lines may take more than a decade. However, this gradual move towards 42V technology in mass- produced vehicles has very important implications regarding the electronic modules used in cars. On top of this, today's typical power consumption for a standard vehicle of 2 kW is forecasted to increase up to 15 kW in the next decade. In addition, looking at the need for the dual 42/14V architecture in the very next few years, the reality is that as the 42V systems evolve, there will be a huge need for driving 14V loads due to the fact that a total switchover to 42V is not feasible. Take the example of lighting; it is a key power application that could still rely heavily on the existing 14V supply even when the 42V systems become commonplace. Besides, given that voltage variations can reduce the life of the bulb filaments, there is a need for voltage stability. What is more, usually some of the functions may require power-handling beyond 200W, which can need supply currents of up to 30A. This is why, with this scenario in mind, no one would dispute that the efficiency and reliability of the DC/DC converters become crucial. In short, the novelty of the power supply design proposed in this paper relies on the fact that robust control techniques are used to design DC/DC converters. In addition, it is shown that the robust control design has robust and optimal performance despite the inevitable disturbances that make the load deviate from its nominal values. Furthermore, QFD techniques are used as tools to better focus on both their applications to the automotive industry and the cost of their implementations. Moreover, the experimental results demonstrate the importance of using robust and optimal control techniques when designing the 42/14V converters for the next-generation cars.