MODELING SALLEN- KEY AUDIO FILTERS IN THE WAVE DIGITAL DOMAIN

Sallen-Key filters are widespread in audio circuits. Therefore, accurate and efficient digital models of such filters are highly desirable in audio Virtual Analog applications. In this paper, we will discuss a possible strategy, based on Wave Digital Filters (WDFs), for implementing all the analog filters described in the historical 1955 manuscript by Sallen and Key. In particular, we will group the eighteen filter models presented by Sallen and Key into ni ne cIasses, according to their topological properties. For each class we will describe the corresponding WDF structures. Finally, we will compare the output signals of WDFs to the output signals of the same models implemented in LTSpice

Wave-Based Analysis of Large Nonlinear Photovoltaic Arrays

open4siIn this paper, a novel analysis method based on wave digital (WD) principles is presented. The method is employed for modeling and efficiently simulating large photovoltaic (PV) arrays under partial shading conditions. The WD method allows rapid exploration of the current-voltage curve at the load of the PV array, given: the irradiation pattern, the nonlinear PV unit model (e.g., exponential junction model with bypass diode) and the corresponding parameters. The maximum power point can therefore easily be deduced. The main features of the proposed method are the use of a scattering matrix that is able to incorporate any PV array topology and the adoption of independent 1-D nonlinear solvers to handle the constitutive equations of PV units. It is shown that the WD method can be considered as an iterative relaxation method that always converges to the PV array solution. Rigorous proof of convergence and results about the speed of convergence are provided. Compared with standard spice-like simulators, the WD method results to be 35 times faster for PV arrays made of some thousands elements. This paves the way to possible implementations of the method in specialized hardware/software for the real time control and optimization of complex PV plants.openBernardini, Alberto; Maffezzoni, Paolo; Daniel, Luca; Sarti, AugustoBernardini, Alberto; Maffezzoni, Paolo; Daniel, Luca; Sarti, August

Wave-Based Analysis of Large Nonlinear Photovoltaic Arrays

In this paper, a novel analysis method based on wave digital (WD) principles is presented. The method is employed for modeling and efficiently simulating large photovoltaic (PV) arrays under partial shading conditions. The WD method allows rapid exploration of the current-voltage curve at the load of the PV array, given: the irradiation pattern, the nonlinear PV unit model (e.g., exponential junction model with bypass diode) and the corresponding parameters. The maximum power point can therefore easily be deduced. The main features of the proposed method are the use of a scattering matrix that is able to incorporate any PV array topology and the adoption of independent 1-D nonlinear solvers to handle the constitutive equations of PV units. It is shown that the WD method can be considered as an iterative relaxation method that always converges to the PV array solution. Rigorous proof of convergence and results about the speed of convergence are provided. Compared with standard spice-like simulators, the WD method results to be 35 times faster for PV arrays made of some thousands elements. This paves the way to possible implementations of the method in specialized hardware/software for the real time control and optimization of complex PV plants