IIR Phasor Banks: Causal, delay-free, numerically robust, customizable, uniform-DFT-like perfect reconstruction filter banks

We describe a method for generating causal, stable, numerically robust, IIR, customizable (application specific), perfect reconstruction (PR) filter-banks with zero (or adjustable) reconstruction delay. The ideas presented in this paper extend the concept of Dynamic Phasors as well as the concept of the so-called Phasor Bank Transform, which constitute specific subclasses of filter-banks. We provide an explicit compact characterization of the optimally-robust reconstruction stage of this transform, which can be used with any (customized) choice of its analysis stage. Since the Phasor Bank transform allows causal (real-time) delay-free perfect reconstruction of any input waveform, it is perfectly suited for (closed-loop) control applications. Although the motivating application area of Phasor Banks is Power Systems, such as tracking of time-variant harmonic content under both steady-state (nearly-periodic) and transient operating conditions, the technique presented here can be used in a variety of closed loop applications.