Wyniki 1-5 spośród 5 dla zapytania: authorDesc:"Apinan AURASOPON"

Improvement of Input Power Factor in PWM AC Chopper by Selecting the Optimal Parameters

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A technique for selecting the element values of the PWM AC chopper circuits to improve the input power factor is presented. This technique analyzes the phase angles of input current, output current and voltage for selecting the optimal value of the filter capacitance. This produces the phase angle of input current in phase with that of input voltage. Therefore, the PWM AC chopper can operate at unity input power factor. The simulation by PSpice program and experimental results are used to verify the proposed technique. Streszczenie. Zaprezentowano metodę selekcji elementów choppera PWM AC w celu poprawy wejściowego współczynnika mocy. Metoda polega na analizie kąta fazowego prądu wejściowego, prądu wyjściowego i napięcia w celu optymalizacji pojemności filtru. Dzięki temu chopper pracuje przy współczynniku mocy równym 1. (Optymalny dobór elementów choppera PWM AC w celu poprawy wejściowego współczynnika mocy) Keywords: Buck, boost, buck-boost AC choppers, capacitor filter, pulse width modulated (PWM) AC chopper, power factor Słowa kluczowe: chopper PWM AC, optymalizacja, współczynnik mocy Introduction To variable AC voltage from fixed AC source, there are three basic techniques that have been widely used in AC power applications such as lighting control, industrial heating, soft start induction motor and speed controller for fans and pumps [1]. The first one is the auto transformer. Its winding ratio is controlled by servo motor or by manual regulation. Although, it offers some advantages such as durability and reliability, it has low voltage regulation speed and large size [2]-[4]. The second technique is the phase angle control. The output voltage average can be controlled by firing angle of thyristor [5]. It has some advantages such as simplicity of the control circuit and capability of controlling a large amount of economical power. However, the delay of firing angle causes discontinuation of power flow to appear at both input a[...]

An improved local search involving bee colony optimization using lambda iteration combined with a golden section search method to solve an economic dispatch problem DOI:10.15199/48.2019.01.49

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The operating cost of a power plant mainly depends on the fuel cost of generators which is minimized via economic dispatch. The Economic Dispatch (ED) problem is one of the fundamental issues in power system operation. The main objective is to reduce the cost of energy production taking into account transmission losses while satisfying equality and inequality constraints. The rational distribution of economic load between running units can lead to significant cost savings making it important to research the economic dispatch problem. Several classical methods, such as the lambda iteration method [1], quadratic programming [2], the gradient method [3], dynamic programming [4], linear programming [5], and nonlinear programming [6] have been applied to solve ED problems. However, these methods are not feasible in practical power systems owing to the non-linear characteristics of the generators. Solutions can be limited to achieving a local optimum which leads to less desirable performance. In addition, these methods often use approximations to limit complexity. Recently, a number of researchers have used meta-heuristic optimization techniques, which are unlike conventional mathematical techniques, to solve ED problems in power systems. Different meta-heuristic approaches have proved to be effective with promising performance, such as a Genetic Algorithm (GA) [7]-[9]. Such methods have been inspired by the Darwinian law of optimal survival of a species, Particle Swarm Optimization (PSO) [10]-[12] inspired by the social behavior of bird raising or fish production, Ant Colony Optimization (ACO) [13]-[14] inspired by food habits in an ant colony, and by Tabu Search (TS) [15] as a way to build a better foundation from prior knowledge. This latter method records previous answers and forbids the new solution to converge at the same point for different input data. Other methods to be used include the Cuckoo Search Algorithm (CSA) [1[...]

Hybrid Algorithm combining Lambda Iteration and Bee Colony Optimization to Solve an Economic Dispatch Problem with Prohibited Operating Zones DOI:10.15199/48.2019.10.02

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Reliability, stability, and economic efficiency are very important for the planning and operation of a power generation system. To get profits from the capital invested, efficient economic operation is critical. Operational economics, involving then minimization of power generation and delivery costs, is called Economic Dispatch (ED). The objective of economic dispatch is to minimize the total cost of all generations while satisfying all operating constraints. To solve the problem of economic dispatch, there are two approaches, including classical and meta-heuristic methods. Classical methods, such as lambda iteration and gradient methods are the most common ones applied to solve the continuous ED problem [1]-[2]. These methods require incremental fuel cost curves which are piecewise and linear. Lagrangian relaxation [3] and dynamic programming [4] is one of the approaches that are used to solve a non-linear and discontinuous ED problem. Numerical methods can cause problems in complicated and large power systems as they suffer from the complexities of dimensionality and local optimality. Recently, meta-heuristic methods have been used to solve the economic dispatch problem. Such methods include simulated annealing (SA) [5]-[6], a genetic algorithm (GA) [7]-[8], an evolutionary program (EP) [9]-[10], tabu search (TS) [11], particle swarm optimization (PSO) [12]-[14], ant colony optimization (ACO) [15]-[17] and bee colony optimization (BCO) [18]-[20]. These methods can obtain a global optimum within a short time and guarantee an optimum solution. However, in these techniques the initial populations are generated randomly. This results in long computation times and a long time to convergence when the generated initial populations are too far from the optimum solution. This problem has been solved by HLBCO [21]-[22] in which the initial population of BCO is modified. However, this method considers a static economic dispatch si[...]

Design of Bandgap Core and Startup Circuits for All CMOS Bandgap Voltage Reference

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This paper proposes a new self-biased op-amp’s startup circuit design and improved bandgap core circuit for all CMOS bandgap voltage reference (BGR). In a conventional BGR circuit, the startup circuit may be designed either be required an external power on reset signal (POR) or composed of several MOS transistors for generating bias current and the bandgap core circuits has two nodes that are controlled currents and voltages by resistors of the same value. The new startup circuit presented here is designed by using only one NMOS transistor with circuit solutions suitable for low supply-voltage operation and achieved the correct bias point stability at the power on and the bandgap core circuit is defined the currents and voltages only one node which can be controlled by input voltages definition of op-amp are equalized for reducing the number of resistor. The simulation results indicate reference voltage of about 500.2 mV, temperature coefficient(TC) of 5ppm/°C, which can be successfully operated with a minimum power supply of 1.2V at a temperature of 0-100°C and a total power dissipation of 10.7 W at room temperature. Streszczenie. W artykule zaproponowano nowe możliwości projektowania CMOS pasmowych wzorców napięcia. W obwodach konwencjonalnych wymaga ne jest użycie zewnętrznego sygnału resetu albo użycie kilku tranzystorów MOS generujących prąd polaryzacji. W nowej koncepcji wykorzystywane są tylko tranzystory NMOS co umożliwia pracę przy niskim napięciu zasilającym. (Projektowanie pasmowego rdzenia i obwodu startowego pasmowych źródeł napięcia referencyjnego) Keywords: Band gap voltage reference, BGR, CMOS, POR. Słowa kluczowe: napięcie referrencyjne, CMOS.. Introduction Reference voltage generators are extensively used in many applications of analog and digital circuits such as A/D, D/A, DRAM and flash memories. The low-power and lowvoltage operations are increasingly in demand for batteryoperated portable devices. The [...]

An Improvement of CMOS Voltage Reference

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This paper presents a CMOS voltage reference design, which is widely used in electronic circuits, both analog and digital circuits. In the conventional, a CMOS voltage reference circuit design composed of several MOS transistors and complicated circuits, the output voltage cannot be adjusted to any levels. Therefore, in this paper proposed the CMOS voltage reference circuit design technique based on current combination circuit, which it was reduced number of MOS transistors and the proposed circuit is able to operate without complex startup circuit. The performance of the proposed circuit is confirmed through PSPICE simulation results, the circuit can be operated with supply voltage varies from 1.85 - 4 V, the output voltage reference is about 500±2.5 mV at wide temperature range of -58 oC to 120 oC, it has very low temperature coefficient of about 61.19 ppm/ oC, and low power dissipation is 5.51 μW. Streszczenie. W artykule opisano ulepszone źródło napięcia wzorcowego w technologii CMOS. W ulepszonej technologii wykorzystuje siemniej tranzystorów a możliwość ustawiania napięcia jest bardziej uniwersalna niż w typowych układach tego typu. (Ulepszone źródło napięcia wzorcowego w technologii CMOS) Keywords: Temperature compensation, CMOS, Voltage reference, Weak inversion. Słowa kluczowe: in the case of foreign Authors in this line the Editor inserts Polish translation of keywords. Introduction The voltage reference circuit was developed and widely applied to electronic circuits which the stable power supply voltage requirement for proper circuit operations such as A/D and D/A converter, DRAM Flash memories, PLLs and others[1-3]. The low-power and low-voltage operations are widely used for portable devices, biomedical sensor and also included shopping intelligence tool in superstore [4-6]. The output voltage of generators are designed with low sensitivity to temperature, fabrication process and power supply variations. The CMO[...]

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