Implementation Of Power Control Research Articles

A Course Controller with Finite-Time Stability for Unmanned Surface Vehicle Thruster System

Aiming at the situation that small unmanned surface vehicle (USV) encounters unknown disturbance during low speed sailing, a course controller with finite time stability is designed. To solve this problem, we construct an undisturbed ideal navigation model which simply meets the stability requirements, and constructs an adaptive sliding mode surface. The control under finite time approach law is also introduced. The model under perturbation can land on the sliding mode surface in finite time and then synchronize with the ideal navigation model. The adaptive control was applied in the implementation of power control for the thruster structure, so as to ensure the tracking of the desired course within the finite time, and satisfy the needs for the stable system performance. Lyapunov direct method is used to strictly prove that the designed controller can ensure the system which converges to the steady state value in a given time period. Simulation results show that the designed adaptive finite-time controller can ensure the stable course tracking of the USV with thruster structure at low speed, and meet the requirements of the course robustness of the USV under dynamic conditions.

A Genetic Algorithm for Optimizing Yaw Operation Control in Wind Power Plants

A genetic algorithm is proposed to optimize the yaw control system used for the stable and efficient operation of turbines in wind power plants. In particular, the factors that produce yaw static deviation are analyzed. Then, the sought optimization method for the yaw static deviation of the wind turbine is implemented by using a lidar wind meter in the engine room in order to solve the low accuracy problem caused by yaw static deviation. It is shown that fuzzy control can overcome problematic factors such as the randomness of wind direction and track the change of wind direction accurately. Power control implementation is simple, as only the voltage and current of the generator need to be measured.

Hardware and software load power control in smart home applications based on Taguchi optimisation technique

Power control is one of the concerns in smart grid implementation. The balance between the supplied power and the demand must be maintained so that blackouts are avoided. Smart metres play an important role in establishing this balance. On the other hand, power control implementation is a challenge as one would have to find the right mix between the hardware and the software parts. The purpose of this work is to optimise and implement a small power control system of home appliances. The objective of the optimisation is to reschedule some tasks if the power demand exceeds a certain peak level. The optimisation is based on Taguchi method which is known of its robustness and relatively fast convergence. The system casts a real life situation and can be considered as a small-scale prototype that can be extended to larger systems.

Fuzzy-predictive direct power control implementation of a grid connected photovoltaic system, associated with an active power filter

The present paper proposes a real time implementation of an optimal operation of a double stage grid connected photovoltaic system, associated with a shunt active power filter. On the photovoltaic side, a fuzzy logic based maximum power point taking control is proposed to track permanently the optimum point through an adequate tuning of a boost converter regardless the solar irradiance variations; whereas, on the grid side, a model predictive direct power control is applied, to ensure both supplying a part of the load demand with the extracted photovoltaic power, and a compensation of undesirable harmonic contents of the grid current, under a unity power factor operation. The implementation of the control strategies is conducted on a small scale photovoltaic system, controlled via a dSPACE 1104 single card. The obtained experimental results show on one hand, that the proposed Fuzzy logic based maximum power taking point technique provides fast and high performances under different irradiance levels while compared with a sliding mode control, and ensures 1.57% more in efficiency. On the other hand, the predictive power control ensures a flexible settlement of active power amounts exchanges with the grid, under a unity power functioning. Furthermore, the grid current presents a sinusoidal shape with a tolerable total harmonic distortion coefficient 4.71%.

Flywheel induction motor-generator for magnet power supply in small fusion device.

A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms).

Calculating Limits of Base Station Emission Power in GSM

This paper compares the influence of various factors on the output power of each GSM channel and connection, and on the output power of whole base transceiver station in GSM network. The considered factors are the influence of sending signal only when speech exists (DTX), implementation of power control in signal sending, influence of users' distribution in the range of coverage of base station, the power of one intra-cell connection and the power of one half-rate connection. It is analyzed how emission power of base station can be reduced by implementing various methods in signal sending.

Experimental Evaluation of Voltage Positive Feedback Based Anti-Islanding Algorithm: Multi-Inverter Case

The novel scenario of power systems with massive utilization of distributed generation (DG) imposes that islanding detection methods for voltage source inverter (VSI)-interfaced DGs must be evaluated taking into account multi-inverter configurations. This paper presents the experimental validation of an active islanding detection algorithm for multi-inverter systems proposed by the authors in previous work. Field programmable gate array implementation of power control and islanding detection algorithms has been used to test this proposition in a multi-inverter system based on grid-connected insulated gate bipolar transistor VSIs. The proposed islanding detection algorithm offers a very low impact on power quality and rapid and efficient islanding confirmation which is demonstrated by simulation and experimentation. The performance of the algorithm was tested under critical conditions as resonant load with high quality factor and unity power factor and also for cases where load and VSI powers are matched.

Joint Control of Transmit Power and Frame Size for Energy-Optimized Data Transfer in Wireless Sensor Networks

Energy efficiency is one of the most important attributes in sensor network protocols. In sensor nodes, communication related activities consume the major share of battery energy. Therefore, judicious choice of transmit power and frame size are very important to maximize the energy efficiency and hence the lifetime of nodes. While there have been a few recent studies on transmit power control implementation in sensor nodes, no report has thoroughly investigated transmit power control and the effect of its interplay with frame size on nodal energy saving. In this paper, we report our implementation of automatic transmit power control in wireless sensor nodes based on open loop parameters — namely, link layer frame size, and close loop parameters — namely, number of consecutive positive acknowledgments and receive signal strength. Our extensive indoor and outdoor experimental results show that, for low to moderate transmission distances, transmit power control has the energy saving benefit, and the larger the frame size the more the energy saving. At a higher transmission distance or at a more error-prone communication scenario, transmit power control as well as a large frame size are detrimental to energy saving performance. The results from this study could be useful in deciding power control strategies and optimum frame length. key words: implementation studies, automatic transmit power control, frame size control, open loop power control, close loop power control, minimum energy transmission

Uplink power control for TDMA portable radio channels

Power control based on signal-to-interference ratio (SIR) has been proposed as a technique for managing co-channel interference in frequency reuse radio systems. Recently, new autonomous power control methods were introduced to achieve near-optimum performance without difficult centralized control proposed earlier. The achievable performance from preliminary studies appears promising for providing significant increase in spectrum efficiency. However, the implementation of the SIR-based power control algorithms remains challenging. In this paper, implementation of power control that indirectly depends on SIR is discussed. As an example, a simple closed-loop power control algorithm for the portable transmitter is introduced for TDMA portable radio systems. While it may appear specific for the system considered, the underlying principle and parameters required (i.e., error indicator, received power level, and signal quality indicator) are common to the implementation of digital demodulation circuitry. Computer simulations indicate that SIR level is maintained at a level suitable for sustaining desirable performance. Furthermore, when the power-control updating period is short, as in the specific system considered, moderate-rate short-term fading can be tracked and mitigated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>