This study presents a procedure for tuning proportional-integral/proportional-integral-derivative controllers using the frequency response method via Bode diagrams, which is relatively simple and easy to understand, and can be used when phase margin and 0 dB gain crossover frequency are project specifications. The method is validated in a practical power electronics application, considering the current and the DC-bus voltage loops of a shunt active power filter (SAPF). A detailed analysis related to the obtaining of the DC-bus voltage loop is also provided. In addition, a stability analysis is presented, considering how the SAPF compensation current is influenced according to the load current, taking into account different values of the grid impedance. Simulation and practical results show the effectiveness of the proposed scheme and its simplicity for being considered in practical cases.

This study proposes a phase-locked loop (PLL) algorithm employed for phase-angle detection of single-phase utility grid voltage. A detailed stability analysis is performed, as well as its performance is evaluated under several power quality problems. The proposed PLL structure is based on the instantaneous active power theory for three-phase power systems (pPLL), which is investigated into the fictitious two-phase stationary reference frame (αβ-pPLL). A non-autonomous adaptive filter (AF) operates in conjunction with the PLL, and its main function is to extract the fundamental component of the utility grid voltage allowing the rejection of voltage harmonics. The stability analysis of the proposed AF-αβ-pPLL scheme is carried out in order to provide adequate tuning procedures for choosing the parameters used in the proposed algorithm. In addition, the dynamic response and robustness of the AF-αβ-pPLL algorithm are evaluated by means of simulation and experimental tests, under utility grid disturbances, such as voltage harmonics, voltage sag, phase jumps and frequency variations. To emphasise the effectiveness of the algorithm, a comparative analysis with three other single-phase PLL schemes is carried out, such as the conventional power-based PLL (pPLL), the two-phase stationary reference frame pPLL (αβ-pPLL) and the well-known enhanced PLL (EPLL).

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1.IntroductionIn the current telecommunication scenario, companies must deal with spectrum scarcity, power consumption issues, increasing throughput demand, and quality of service (QoS) requirements, including high performance (in terms of bit error rate (BER)) with guarantees of delivering the target information rate per user-class, maximum allowed delay, and so on. In these situations, many optimization problems arise, such as multiuser detection and resource allocation. A lot of innovative algorithms conception and research efforts have been spent in order to satisfy the new services requirements, such as growing capacity, availability, mobility, and multiclass services (i.e., multirate users) with different quality of service (QoS). Hence, inspired by this scenario, a different optimization approach based on heuristic procedures has been investigated. Particle swarm optimization (PSO) was developed after some researchers have analyzed the birds behavior and discerning that the advantage obtained through their group life could be explored as a tool for a heuristic search. Considering this new concept of interaction among individuals, J. Kennedy and R. Eberhart developed a new heuristic search based on a particle swarm Kennedy & Eberhart (1995). The PSO principle is the movement of a group of particles, randomly distributed in the search space, each one with its own position and velocity. The position of each particle is modified by the application of velocity in order to reach a better performance. The interaction among particles is inserted in the calculation of particle velocity. In a multiple access DS/CDMA system, a conventional detector by itself may not provide a desirable performance and quality of service, once the system capacity is strongly affected by multiple access interference (MAI). The capacity of a DS/CDMA system in multipath channels is limited mainly by the MAI, self-interference (SI), near-far effect (NFR) and fading. The conventional receiver for multipath channels (Rake receiver) explores the path diversity in order to reduce fading impairment; however, it is not able to mitigate neither the MAI nor the near-far effect Moshavi (1996);Verdú (1998). In this context, multiuser detection (MUD) emerged as a solution to overcome the MAI. The best performance is acquired by the optimum multiuser detection (OMUD), which is based on the log-likelihood function (LLF), but results

Advanced Driver Assistance Systems (ADAS) is a group of technologies that support the driving with safety measures, such as the Adaptive Cruise Control (ACC). The ACC System computes a reference, known as cruise speed, that tracks the desired speed but it changes if a leading vehicle draws close. In this paper, the inner loop of ACC was designed using two different Model Predictive Control techniques: finite horizon and infinite horizon of prediction. The dynamic model of the vehicle was obtained using System Identification. The controllers were embedded in an ACC Module that communicates directly with a customized Electronic Control Unit (ECU) of the vehicle. The validation of the controllers is performed with practical experiments using a dynamometer. INDEX TERMSAutomotive applications, cruise control, predictive control, quadratic programming, system identification.

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