Auto tuning of digital deadbeat controllers for high performance AC voltage sources using wide bandwidth impedance identification

Abstract

By injecting a small signal pseudo-random binary sequence (PRBS) based injection sequence, chosen for its wideband spectral content, into the inverter's PWM control signal and utilizing digital network analyzer techniques, an accurate estimation of the output impedance can be obtained without external equipment. This knowledge can then be leveraged to tune the inverter's digital deadbeat controllers for optimal performance, i.e. reaching the desired reference in n switching cycles, where n is the order of the system.