10/27/2022 0 Comments Amx to pwm converterExperiments that are based on a simple digital implementation are provided to illustrate the merits of our solution. In addition, the passivity properties of the proposed scheme are presented, which open the possibility of control design following the passivity-based approach. The proposed scheme is, then, plugged into a generic feedback control system where a stability analysis is carried out. AMX TO PWM CONVERTER PLUSThe control scheme is based on the feedback array of two delay lines plus a feedforward path that compensates only the 6 lscr plusmn 1 multiples of the fundamental frequency, thereby reducing the possibility of reinjecting unnecessary distortion into the system. This control scheme is more appropriate for processes that involve the use of six-pulse converters or other converters that mainly produce harmonic components at those frequencies. In this paper, a repetitive-based controller for the compensation of 6 lscr plusmn 1 harmonic components is proposed. Contributions of this dissertation have been published in three JCR-indexed journal papers and presented at two international conferences. A systematic method, supported by closed-form analytical expressions, is proposed to obtain the highest stability and performance, even when there are multiple 0 dB crossings. It is proved that the minimization of the sensitivity peak permits to achieve a greater performance and stability rather than by maximizing the gain or phase margins. In this thesis, resonant controllers are analyzed by means of Nyquist diagrams. This situation arises in cases such as selective control and when relatively high resonant frequencies with respect to the switching frequency are required (e.g., in high power converters, where the switching frequency should be low in order to reduce the commutation losses). The existing methods, which are mainly based on the phase margin criterion, present some limitations, specially when there are multiple 0 dB crossings in the gain versus frequency response. Finally, the analysis and design of resonant controllers is approached. Alternative implementations based on two integrators are proposed in this dissertation, which achieve higher performance by means of more accurate resonant peak locations and delay compensation, while maintaining the advantage on low computational burden and good frequency adaptation of the original schemes. However, it is proved in this thesis that these schemes require lower resource consumption, but at the expense of important inaccuracies that significantly worsen the performance, except for very low resonant frequencies and sampling periods. The implementations of resonant controllers based on two interconnected integrators are widely employed due to their simplicity regarding frequency adaptation. The optimum discrete-time implementation alternatives are assessed, in terms of their influence on the resonant peak location and the phase versus frequency response. The discretization process is proved to be of great importance in these regulators, mainly because of their resonant characteristics. One of the contributions of this thesis consists in an in-depth comparison among the effects of discretization strategies when applied to resonant controllers. Several discrete-time implementations of resonant controllers have been proposed, but a comparison among the performance obtained by a wide variety of discretization techniques applied to resonant controllers has not been presented at this point. In nowadays scenarios, most current controllers are implemented in digital platforms, so the influence of the discretization process should not be ignored. Most studies devoted to resonant controllers have been carried out in the continuous domain however, their observations and conclusions cannot be directly applied to digital devices, which work in the discrete-time domain. Nevertheless, there are certain aspects with regard to these controllers that have not been approached in the technical literature on the matter, and that should be investigated in order to take advantage of their actual potential. One of the most extended types of current regulators are resonant controllers, which achieve zero steady-state error at selected frequencies, while providing a good combination of simplicity and high performance. Sinusoidal current regulation of voltage source converters is an aspect of paramount importance to achieve a high level of performance in a lot of different applications, such as ac motor drives, active power filters, wind turbines, static synchronous compensators, photovoltaic inverters or active rectifiers.
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