Investigations on Output Impedance Measurement of Digitally Controlled Power Converters with Wide Bandwidth Signals

Impedance-based stability criteria can be a powerful tool in systems analysis of microgrids. Especially in terms of low-voltage direct current grids, the amount of available power converters continuously increases. Since commercial components are typically black-boxes for system analysis, reliable and fast measurement is required to allow for accurate stability estimations. Here, wide bandwidth signals offer reduced measurement time at high accuracy. Since higher power converters are often digitally controlled, this paper investigates requirements for proper wide bandwidth impedance measurement under the boundary conditions the digital control enforces on time and value quantization.