การแก้ปัญหาการไหลกำลังไฟฟ้าเหมาะที่สุดโดยใช้วิธีการค้นหาความบรรสาน

This paper presents optimal power flow solutions in which the system production cost is set as the objective. Harmony Search (HS) was selected as an efficient intelligent search method. The standard IEEE 6- bus and 30-bus test systems were used for evaluation. The satisfactory results obtained by the HS method were compared with those obtained by Quasi-Newton methods (BFGS) and Genetic Algorithms (GA). As a result, the HS method showed performances in finding optimal solutions for the optimal power flow problems

Metal-embedded SU-8 Slab Techniques for Low-resistance Micromachined Inductors

This work presents a new fabrication technique for micro power inductors by using metal-embedded SU-8 slab molding techniques. The proposed technique uses X-ray lithography to fabricate high-aspect-ratio LIGA-like microstructures in form of embedded structures in the SU-8 slab. This process was applied to fabricate an inductor’s windings with an aspect ratio of 10, which can provide very low resistance but still preserve a small form factor and low profile. Inductors were designed as pot-core structures with overall heights of 370 μm and embedded with 250-μm-thick windings. From the advantage of metal embedded SU-8 slab techniques, 8 μm-thick permalloy core could be fabricated by electroplating around the winding in a single step that could help simplify the process. Four types of inductors were fabricated with 3, 5, 10, and 16 turns in the area of 1.8 to 9.5 mm2. The measured inductance was in the range of 70 nH to 1.3 μH at 1 MHz and DC resistance of 30–336 mΩ for 3–16 turns, respectively. The DC resistance of fabricated inductor was low, as expected, and showed good result compared with the results in literature

Optimising AC electric railway power flows with power electronic control

The latest generation of AC-fed traction drives, employing high-speed switching devices, is able to control the reactive power drawn from the overhead line by each equipment. If the conditions at each locomotive or train could be fed back to a central control point, it is possible for a centrally located controller to calculate optimal values for the reactive power in each drive and to send those commands back to the individual equipment. In this thesis, AC railway power flows are optimised in real time and the results are used to achieve some particular system objective via control of the PWM equipment as mobile reactive power compensators. The system voltage profile and the total power losses can be improved while the overall power factor at the feeder substation is also made nearer to unity. For off-line simulation purposes, high execution speeds and low storage requirements are not generally significant with the latest computer hardware. However, this real-time control employs on-line optimising controllers, which need embedded power solvers running many times faster than real time. Thus, a fast and efficient algorithm for AC railway power flow calculation was developed. The proposed scheme is compared to a conventional reactive power compensation, e.g. SVC, and found to be less expensive to implement. Several test cases for AC electric railway systems are examined. The centralised area control system leads to the best improvement where an existing fleet of diode or thyristor phase-angle controlled locomotives is partially replaced with PWM ones, compared to that obtained without compensation or to classical track-side Var compensation methods. From these results, the potential for PWM locomotives to improve overall system performance is confirmed