Synthesis of Sinusoidal Waveform References Synchronized With Periodic Signals

摘要

This paper proposes a novel method to generate a sinusoidal waveform synchronized with any measurable periodic signal whose frequency is within a given neighborhood. The synthesized sinusoidal signal could be used as a reference current for certain applications of parallel active power filters or any other where such synchronization would be necessary (e.g., ac/dc converters for renewable energy resources, power factor correctors, power supplies, UPS, etc.) The method is based on the behavior of a dynamical system and avoids employing the usual combination of phase-locked loop (PLL) and lookup table found in most parallel active filters synthesizing a sinusoidal source current (a table also means using significant storage memory). The novel method produces two high-quality sinusoidal waveforms that are in quadrature and is applicable to those parallel active filters whose control methodology is in the $alpha beta$ reference frame, or alternatively, it produces three sinusoidal waveforms shifted 120 degrees for designs that work in the $abc$ frame. Here, a $(2n+1)$ th order implementation is described, including a proof of convergence. For its most simple implementation $(n = 1)$, simulated and experimental results are included.