10 - Digital control strategies of DC–DC converters in automotive hybrid powertrains

Abstract

DC–DC converters are presented in many electric vehicle powertrain systems. This kind of converters is the most basic element of such a powertrain system. Its operation is of vital importance for the proper operation of the whole system. In the context of electric vehicles a wide variety of DC–DC converter topologies have been proposed, but all with something in common: they are digitally regulated by a current control. This chapter explores the digital design of some current control techniques of classic DC–DC converters (boost and buck), which can be part of a much more complex system like the electric vehicle powertrain. The presented digital current techniques can be extended to other more complex DC–DC converter topologies and can also be used as part of even more complex controls, such as a double loop control design, which is also presented in this chapter. Finally, for each of the proposed controls, we give a detailed information, which allows its software-in-the-loop testing. This way, the use of the simplified C block in PSIM allows us to enter a custom C code directly without compiling the code. This advantage allows us to incorporate an external C code, as used in a digital signal controller (DSC), into a simulation model whereby comparison of different proposed digital controls can be easily made. In addition, most simulation programs support C code, such as PLECS, PSIM, MATLAB, and so on. Therefore digital controllers presented in this chapter can be extended to other simulation programs in a simple way.