scholarly journals Sliding Mode Control Techniques for Combined Energy and Attitude Control System

2014 ◽  
Vol 629 ◽  
pp. 310-317 ◽  
Author(s):  
Samira Eshghi ◽  
Renuganth Varatharajoo

Combined Energy and Attitude Control System (CEACS) is an optimization approach that combines the energy storage system and the attitude control system. With a double counter rotating flywheel simultaneously serving as energy storage device and as attitude control actuator, CEACS requires an accurate control strategy to obtain the mission requirements. In addition, it is important to design the control law to be invariant to uncertainties and disturbances, and guarantee robustness as CEACS inherits these in-orbit uncertainties. This paper presents a nonlinear control employing sliding mode to enhance the CEACS attitude control capability. The mathematical model for the conventional and boundary layer sliding mode controls are developed herein for CEACS. The controller provides enhancement in pointing accuracies, reasonable transient responses and a robustness against uncertainties and in-orbit disturbances.

2021 ◽  
Vol 69 (2) ◽  
pp. 5-12
Author(s):  
Zheng Li ◽  
Yan Qin ◽  
Xin Cao ◽  
Shaodong Hou ◽  
Hexu Sun

In order to meet the load demand of power system, BP based on genetic algorithm is applied to the typical daily load forecasting in summer. The demand change of summer load is analysed. Simulation results show the accuracy of the algorithm. In terms of power supply, the reserves of fossil energy are drying up. According to the prediction of authoritative organizations, the world's coal can be mined for 216 years. As a renewable energy, wind power has no carbon emissions compared with traditional fossil energy. At present, it is generally believed that wind energy and solar energy are green power in the full sense, and they are inexhaustible clean power. The model of wind power solar hydrogen hybrid energy system is established. The control strategy of battery power compensation for delayed power of hydrogen production is adopted, and different operation modes are divided. The simulation results show that the system considering the control strategy can well meet the load demand. Battery energy storage system is difficult to respond to short-term peak power fluctuations. Super capacitor is used to suppress it. This paper studies the battery supercapacitor complementary energy storage system and its control strategy. When the line impedance of each generation unit in power grid is not equal, its output reactive power will be affected by the line impedance and distributed unevenly. A droop coefficient selection method of reactive power sharing is proposed. Energy storage device is needed to balance power and maintain DC voltage stability in the DC side of microgrid. Therefore, a new droop control strategy is proposed. By detecting the DC voltage, dynamically translating the droop characteristic curve, adjusting the output power, maintaining the DC voltage in a reasonable range, reducing the capacity of the DC side energy storage device. Photovoltaic grid connected inverter chooses the new droop control strategy.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2048 ◽  
Author(s):  
Rodrigo Martins ◽  
Holger Hesse ◽  
Johanna Jungbauer ◽  
Thomas Vorbuchner ◽  
Petr Musilek

Recent attention to industrial peak shaving applications sparked an increased interest in battery energy storage. Batteries provide a fast and high power capability, making them an ideal solution for this task. This work proposes a general framework for sizing of battery energy storage system (BESS) in peak shaving applications. A cost-optimal sizing of the battery and power electronics is derived using linear programming based on local demand and billing scheme. A case study conducted with real-world industrial profiles shows the applicability of the approach as well as the return on investment dependence on the load profile. At the same time, the power flow optimization reveals the best storage operation patterns considering a trade-off between energy purchase, peak-power tariff, and battery aging. This underlines the need for a general mathematical optimization approach to efficiently tackle the challenge of peak shaving using an energy storage system. The case study also compares the applicability of yearly and monthly billing schemes, where the highest load of the year/month is the base for the price per kW. The results demonstrate that batteries in peak shaving applications can shorten the payback period when used for large industrial loads. They also show the impacts of peak shaving variation on the return of investment and battery aging of the system.


Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2854 ◽  
Author(s):  
Danijel Pavković ◽  
Mihael Cipek ◽  
Zdenko Kljaić ◽  
Tomislav Mlinarić ◽  
Mario Hrgetić ◽  
...  

This contribution outlines the design of electric vehicle direct-current (DC) bus control system supplied by a battery/ultracapacitor hybrid energy storage system, and its coordination with the fully electrified vehicle driveline control system. The control strategy features an upper-level DC bus voltage feedback controller and a direct load compensator for stiff tracking of variable (speed-dependent) voltage target. The inner control level, comprising dedicated battery and ultracapacitor current controllers, is commanded by an intermediate-level control scheme which dynamically distributes the upper-level current command between the ultracapacitor and the battery energy storage systems. The feedback control system is designed and analytical expressions for feedback controller parameters are obtained by using the damping optimum criterion. The proposed methodology is verified by means of simulations and experimentally for different realistic operating regimes, including electric vehicle DC bus load step change, hybrid energy storage system charging/discharging, and electric vehicle driveline subject to New European Driving Cycle (NEDC), Urban Driving Dynamometer Schedule (UDDS), New York Certification Cycle (NYCC) and California Unified Cycle (LA92), as well as for abrupt acceleration/deceleration regimes.


2018 ◽  
Vol 180 ◽  
pp. 02005 ◽  
Author(s):  
Włodzimierz Jefimowski ◽  
Anatolii Nikitenko

The paper presents the results of economic study of energy storage system (ESS) implemented in 3 kV DC power supply system. Two conceptions of ESS have been investigated: ESS with supercapacitor (SC) and hybrid ESS (HESS) with SC and LFP battery. The investigated locations of energy storage systems are considered among existing traction substations in two railway lines with different density of train operation. The considered aims of energy storage system implementation are decreasing of energy consumption by maximum regenerative energy utilization and reduction of peak 15- min power demand of traction substation. The paper presents a method of regenerative power estimation depending on the location of the considered ESS implementation point. Also the method of optimal location selection of ESS in terms of minimization of Simple Payback Time (SPBT) of investment is presented. Besides the influence of initial cost value as well as energy price on the SPBT value are investigated. The results are compared between two railway lines with different number of trains operating.


2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Mingyi Huo ◽  
Yanning Guo ◽  
Xing Huo

This work presents a novel fault reconstruction approach for a large-scale system, that is, a distributed coordinated spacecraft attitude control system. The attitude of all the spacecrafts in this distributed system is controlled by using thrusters. All possible faults of thruster including thrust magnitude error and alignment error are investigated. As a stepping stone, the mathematical model of thruster is firstly established based on the thruster configuration. On the basis of this, a sliding mode observer is then proposed to reconstruct faults in each agent of the coordinated control system. A Lyapunov-based analysis shows that the observer asymptotically converges to the actual faults. The key feature of this fault reconstruction approach is that it can achieve a faster reconstruction of the fault in comparison with the conventional fault reconstruction schemes. It can globally reconstruct thruster faults with zero reconstruction error, and this is accomplished within finite time. The effectiveness of the proposed approach is analytically authenticated via simulation study.


2014 ◽  
Vol 1008-1009 ◽  
pp. 1466-1469
Author(s):  
Gui Xing Wang ◽  
Zhe Heng Zhou ◽  
Shuai Zheng ◽  
Qing Xie ◽  
Chao Ping Rao ◽  
...  

In this research, a storage system, suitable for the power system of construction, is proposed and optimized. The storage system mainly consists of control system, converter, flywheel and motor. This system can release the pressure of the power grid during the on-peak period and supply the consumers with cheap energy. This research is going to analyze the characters of the system and then adjust its structure to the architecture.


2018 ◽  
Vol 7 (4.13) ◽  
pp. 99
Author(s):  
Azizi Malek ◽  
M F Sedan ◽  
A S M Harithuddin

This paper documents and presents the development of attitude control system of Hybrid Airship Unmanned Aerial Vehicle (HAU) that should be able to change its attitude condition based on the response processed from the provided input. This is accomplished by data acquisition method that retrieves data from a flight controller and processes it into the control system without looking in deep on the mathematical model of the airship. Besides that, PID controller is used in order to create a good stable response for the hybrid airship. A working hybrid airship prototype was successfully developed and built, which is five meters in length and has four propellers that is symmetrically distanced to each other. A quadcopter attitude control mechanism is adopted into the hybrid airship to allow for good hovering capability and direct pure attitude control. Outdoor flight tests have been conducted to prove its stability in responding to attitude input given to the hybrid airship attitude controller. A data monitoring software is also written to make the data observation on the behaviour of the hybrid airship response to be easier and understandable. Result demonstrates that the hybrid airship does response to pitch, roll and yaw input from the operator, albeit the lack response stability and speed which can be improved in conservative continuation of research on the airship attitude control system.  


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