Open AccessDSP-Based Control of Multi-Rail DC-DC Converter Systems with Non-Integer Switching Frequency Ratios
Author(s) -
James Mooney,
Simon Effler,
Mark Halton,
Abdulhussain E. Mahdi
Publication year - 2011
Publication title -
iraqi journal for electrical and electronic engineering/al-maǧallaẗ al-ʻirāqiyyaẗ al-handasaẗ al-kahrabāʼiyyaẗ wa-al-ilikttrūniyyaẗ
Language(s) - English
Resource type - Journals
eISSN - 2078-6069
pISSN - 1814-5892
DOI - 10.37917/ijeee.7.1.3
Subject(s) - interrupt , converters , duty cycle , digital signal processing , digital control , electronic engineering , digital signal processor , computer science , controller (irrigation) , power (physics) , voltage , control theory (sociology) , engineering , computer hardware , electrical engineering , control (management) , microcontroller , agronomy , physics , quantum mechanics , artificial intelligence , biology
This paper examines the use of non-integer switching frequency ratios in digitally controlled DC-DC converters. In particular the execution of multiple control algorithms using a Digital Signal Processor (DSP) for this application is analyzed. The variation in delay from when the Analog to Digital Converter (ADC) samples the output voltage to when the duty cycle is updated is identified as a critical factor to be considered when implementing the digital control system. Fixing the delay to its maximum value is found to produce reasonable performance using a conventional DSP. A modification of the DSP’s interrupt control logic is proposed here that minimizes the delay and thereby yields improved performance compared with that given by a standard interrupt controller. Applying this technique to a multi-rail power supply system provides the designer with the flexibility to choose arbitrary switching frequencies for individual converters, thereby allowing optimization of the efficiency and performance of the individual converters.