Power Alignment, New Digital Control Approach for a DC-DC Flyback Converter with Constant Power Loads

Power electronic components are inevitable parts of advanced vehicular power systems, because of their high efficiency and high power densities. Power electronic components, when tightly regulated; behave as constant power loads (CPLs). In order to mitigate the problem of negative impedance instability this paper presents Power Alignment, a new digital control technique for converters with constant power loads (CPLs). This approach uses two predefined state variables instead of conventional pulse width modulation (PWM) to regulate the output voltage. A comparator compares actual output voltage with reference voltage and then switches between appropriate states. It needs few logic gates and comparators to implement digital control, thus making it extremely simple and easy to develop a low cost application specific integrated circuit (ASIC) for converters with CPLs. Simulation and analytical results are presented to describe and verify the proposed technique.