Stability Analysis and Efficiency Improvement of a Multi-converter System Using Multi-objective Decision Making

Multi-converter system is mainly used in advanced automotive systems. Different converters and inverters are taking part in automotive systems to provide different voltage levels in a multi-converter system. It involves constant voltage load (CVL), constant power load (CPL) and other loads. The CPL in such systems offers negative impedance characteristic and it creates a destabilizing effect on the main converter. The effect of destabilization can be reduced by increasing the CVL or inserting parasitic components. Attempts have been made by authors to improve the stability by using parasitics of different components such as switch, diode and inductor. Influence of insertion of parasitics including the series equivalent resistance of the filter capacitor and variation in CVL on the performance of main converter is mathematically analyzed and conflicting behavior between system stability and efficiency is observed. The optimum solution between these two functions is obtained by using multi-objective decision making (MODM) by varying parasitics of different components and CVL. An attempt has been made to demonstrate the effect of CVL load and the parasitics on the stability and efficiency of the main converter, experimentally.