Digital Current-Control Schemes

The paper is about comparing the performance of digital signal processor-based current controllers for three-phase active power filters. The wide use of nonlinear loads, such as front-end rectifiers connected to the power distribution systems for dc supply or inverter-based applications, causes significant power quality degradation in power distribution networks in terms of current/voltage harmonics, power factor, and resonance problems. Passive LC filters (together with capacitor banks for reactive power compensation) are simple, low-cost, and high-efficiency solution

Multi-client distributed blind quantum computation with the Qline architecture

Universal blind quantum computing allows users with minimal quantum resources to delegate a quantum computation to a remote quantum server, while keeping intrinsically hidden input, algorithm, and outcome. State-of-art experimental demonstrations of such a protocol have only involved one client. However, an increasing number of multi-party algorithms, e.g. federated machine learning, require the collaboration of multiple clients to carry out a given joint computation. In this work, we propose and experimentally demonstrate a lightweight multi-client blind quantum computation protocol based on a novel linear quantum network configuration (Qline). Our protocol originality resides in three main strengths: scalability, since we eliminate the need for each client to have its own trusted source or measurement device, low-loss, by optimizing the orchestration of classical communication between each client and server through fast classical electronic control, and compatibility with distributed architectures while remaining intact even against correlated attacks of server nodes and malicious clients

Association between obesity and knee osteoarthritis in users of brazilian unified national health system

Verify possible associations between obesity and knee OA in users of Brazilian Unified National Health System (Sistema Único de Saúde - SUS) of primary care network in Catalão-GO, Brazil. This is an observational study conducted in 2014 and 2015. A total of 81 volunteers from the Basic Attention Network in the city of Catalão, with body mass index (BMI) over 30 kg/m2 in both sexes, age between 40 and 60 years, and OA on radiological examination of the knee. Obesity was classified according to BMI. The diagnosis of osteoarthritis (OA) was made clinically and by radiography according to Kellgren radiological classification. The level of physical activity was assessed using the Baecke questionnaire and the Gordon Functional Classification. The volunteers underwent an anthropometric evaluation and physical examination with inspection and palpation of the joint and subsequent radiological examination of the knee. The volunteers answered a questionnaire on the level of physical activity and functional classification. Data analysis was performed using Fisher’s exact test or chi-square test was used for comparisons of two proportions. In comparisons of continuous variables, Student’s t-test or the nonparametric Wilcoxon-Mann-Whitney test was used. The level of significance was set to 5%. Practice of regular physical exercise decreases functional impairment in obese individuals with knee OA. The weight variable demonstrated a strong association with the severity of OA and degree of functionality of patients. Obesity and OA durations and lack of patient guidance are variables that may contribute to the progression of knee OA. Although the incidence among men is lower, they are more severely affected and anthropometric evaluation and physical examination are an efficacy implementations for Brazilian users of SUS

Implementation of a Digital Signal Processor-controlled Shunt Active Filter

This paper presents the implementation of an active filter configuration for harmonic compensation. The system can be controlled for current harmonics and reactive power compensations simultaneously by using a converter operating as active shunt filter. A synchronous reference frame based controller is compared to an instantaneous reactive power based controller. The synchronous reference frame method is chosen to control the converter due to the better performance when the supply voltage is distorted. A shunt active filter system has been designed and built to meet IEEE 519 recommended harmonic standards. Simulation demonstrates the good performance of the active filter configuration. Experimental results, corresponding to the operation of the digital signal processor-controlled shunt active filter are also presented

Enhanced power quality control strategy for Single-Phase Inverters in Distributed generation systems

Power electronic converters are commonly used for interfacing distributed generation (DG) systems to the electrical power network. This paper deals with a single-phase inverter for DG systems requiring power quality features, such as harmonic and reactive power compensation for grid-connected operation. The idea is to integrate the DG unit functions with shunt active power filter capabilities. With this approach, the inverter controls the active power flow from the renewable energy source to the grid and also performs the nonlinear load current harmonic compensation by keeping the grid current almost sinusoidal. The control scheme employs a current reference generator based on sinusoidal signal integrator and instantaneous reactive power (IRP) theory together with a dedicated repetitive current controller. Experimental results obtained on a 4-kVA inverter prototype demonstrate the feasibility of the proposed solutio