This work presents a Comparative study of closed and open loop control system using UPF control strategy for standalone variable speed wind turbine permanent magnet synchronous generator employing space vector modulation voltage source converter. The mechanical energy required to drive the generator is obtained from variable speed wind turbine. Three phase PMSG is excited from three phase VSC. ...

To achieve the soft-switching condition and stabilize the output voltage of quasi-resonant converters, the paper proposes a double closed-loop control method (DCCM). In the inner loop, soft-switching is guaranteed with the off-time of the switch determined by the zero-crossing signal of the switching voltage. In the outer loop, the output voltage is regulated to be constant against load variati...

background: except in emergency cases, all patients should be seen first by a primary healthcare physician who decides whether a referral to secondary care is necessary. the present study examined the reasons for patient self-referral to specialists. methods: a random sample of 1036 individuals was selected from people attending public outpatient clinics and specialists’ offices in the private ...

design of a logistics network in proper way provides a proper platform for efficient and effective supply chain management. this paper studies a multi-period, multi echelon and multi-product integrated forward-reverse logistics network under uncertainty. first, an efficient complex mixed-integer linear programming (milp) model by considering some real-world assumptions is developed for the inte...

in this research, we address the application of uncertaintyprogramming to design a multi-site, multi-product, multi-period,closed-loop supply chain (clsc) network. in order to make theresults of this article more realistic, a clsc for a case study inthe iron and steel industry has been explored. the presentedsupply chain covers three objective functions: maximization ofprofit, minimization of n...

Let M be a closed, connected manifold, and LM its loop space. In this paper we describe closed string topology operations in h∗(LM), where h∗ is a generalized homology theory that supports an orientation of M . We will show that these operations give h∗(LM) the structure of a unital, commutative Frobenius algebra without a counit. Equivalently they describe a positive boundary, two dimensional ...

A constant voltage regulator, to supply constant power loads, is realized using a Switched-capacitor converter. Exhaustive studies have been carried out to find the suitability of available control schemes and finally one control scheme investigated with (i) operation of the converter at different crossover frequencies (ii) operation of the converter at different phase Margins. Various operatin...

This paper presents five SIMULINK libraries for modeling, design, optimization and testing of digital protective relays. The new MATLAB based software package includes the following libraries: Relay Elements, Relays, Protection Systems, Input Signals and Tools. The paper presents the software package in detail. First, all the components are described including their functions and variety of ava...