scholarly journals Research on Optimal Control of Excavator Negative Control Swing System

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1096
Author(s):  
Lijie Zhang ◽  
Wenbo Fu ◽  
Xiaoming Yuan ◽  
Zhaoliang Meng
Keyword(s):  
Control Strategy ◽  
Power Flow ◽  
Negative Control ◽  
System Response ◽  
Hydraulic Brake ◽  
Compound Control ◽  
Brake Pressure ◽  
System Response Time ◽  
Swing Speed ◽  
System Power

In order to improve the energy efficiency and dynamic of negative control swing systems of excavators, this paper proposes a technical scheme of adding two PRVs (pressure reducing valves) to main valve pilot control circuit, which can adjust main value opening arbitrarily according to the working condition. A pump-value compound control strategy was formulated to regulate the system power flow. During swing motor acceleration, main pump and the two PRVs are controlled to match system supply flow with motor demand flow, thereby reducing motor overflow and shortening system response time. During swing motor braking, the channel from motor to tank is opened to release hydraulic brake pressure by controlling PRVs before swing speed reduces to zero, which prevents the motor from reversing and oscillating. A simulation model of 37-ton excavator was established, and the control strategy was simulated. The original and optimized performance of the swing system were compared and analyzed, and results show that the application of new scheme with the compound control strategy can reduce overflow and increase braking stability of the swing system. In addition, system response and speed control performance are also improved when excavator performs a single-swing action.

scholarly journals Transmission Capacity Improvement Using Unified Power Flow Controller with New Control Strategy

2021 ◽  
pp. 225-232
Author(s):  
Moe Moe Oo ◽  
◽  
Myint Thuzar
Keyword(s):  
Control System ◽  
Control Strategy ◽  
Power Flow ◽  
Transmission Capacity ◽  
System Response ◽  
Unified Power Flow Controller ◽  
Transmission Network ◽  
Flow Controller ◽  
Power Flow Controller

This paper presents Unified Power Flow Controller (UPFC) with a new control strategy to improve the transmission capacity in power system network. With the growing demand of electricity, it is not possible to erect new lines to face the situation. Therefore UPFC is optimally utilizes to enhance the existing transmission network. A detail explanation of the controllers for both shunt and series converters of UPFC and DC link capacitor rating are presented in this study. To justify the performance of the UPFC model, 230kV transmission system in Upper Myanmar National Grid is considered as case study. The proposed control system performance is checked by applying different faults across a transmission line to which UPFC is connected. This is necessary because of the chance for occurance of fault is larger for this case study network. And, loading condition is changed to study the control system response. The simulation results show the effectiveness and suitable performance of the control strategy at improving transmission capacity. Transmission network model and all simulations have been done using MATLAB/Simulink software.

scholarly journals Power Flow Control Strategy and Reliable DC-Link Voltage Restoration for DC Microgrid under Grid Fault Conditions

2019 ◽  
Vol 11 (14) ◽  
pp. 3781 ◽  
Author(s):  
Thanh Van Nguyen ◽  
Kyeong-Hwa Kim
Keyword(s):  
Flow Control ◽  
Control Strategy ◽  
Power Flow ◽  
Control Mode ◽  
Abnormal Behavior ◽  
Power Balance ◽  
Dc Microgrid ◽  
Power Flow Control ◽  
Restoration Algorithm ◽  
System Power

In this paper, an effective power flow control strategy (PFCS) based on the centralized control method and a reliable DC-link voltage (DCV) restoration algorithm for a DC microgrid (DCMG) under grid fault conditions are proposed. Considering the relationship of supply-demand power and the statuses of system units, thirteen operating modes are presented to ensure the power balance in DCMG under various conditions. In the PFCS, the battery charging/discharging procedure is implemented considering the battery power limit to avoid overheating and damage. Moreover, load shedding and load reconnection algorithms are presented to maintain the system power balance, even in critical cases. To prevent the system power imbalance in DCMG caused by the delay of grid fault detection, a reliable DCV restoration algorithm is also proposed in this paper. In the proposed scheme, as soon as abnormal behavior of the DCV is detected, the battery or wind power generation system instantly enters a local emergency control mode to restore the DCV rapidly to the nominal value, regardless of the control mode assigned from the central controller. Comprehensive simulations and experiments based on the DCMG testbed are carried out to prove the effectiveness of the PFCS and the proposed DCV restoration algorithm.

scholarly journals Coordinated Control System between Grid–VSC and a DC Microgrid with Hybrid Energy Storage System

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2699
Author(s):  
Miguel Montilla-DJesus ◽  
Édinson Franco-Mejía ◽  
Edwin Rivas Trujillo ◽  
José Luis Rodriguez-Amenedo ◽  
Santiago Arnaltes
Keyword(s):  
Control Strategy ◽  
Power Flow ◽  
Storage System ◽  
Coordinated Control ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Electrical Network ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Dc Microgrid

Direct current microgrids (DCMGs) are currently presented as an alternative solution for small systems that feed sensitive electrical loads into DC. According to the scientific literature, DCMG maintains good voltage regulation. However, when the system is in islanded mode, very pronounced voltage variations are presented, compromising the system’s ability to achieve reliable and stable energy management. Therefore, the authors propose a solution, connecting the electrical network through a grid-tied voltage source converter (GVSC) in order to reduce voltage variations. A coordinated control strategy between the DCMG and GVSC is proposed to regulate the DC voltage and find a stable power flow between the various active elements, which feed the load. The results show that the control strategy between the GVSC and DCMG, when tested under different disturbances, improves the performance of the system, making it more reliable and stable. Furthermore, the GVSC supports the AC voltage at the point of common coupling (PCC) without reducing the operating capacity of the DCMG and without exceeding even its most restrictive limit. All simulations were carried out in MATLAB 2020.

scholarly journals AGC of multi area power system based PSO under deregulated conditions

2018 ◽  
Vol 7 (3) ◽  
pp. 1446
Author(s):  
Ahmed Jasim Sultan ◽  
Falah Noori Saeed
Keyword(s):  
Power Flow ◽  
Optimization Technique ◽  
Automatic Generation ◽  
Automatic Generation Control ◽  
System Response ◽  
Area Control Error ◽  
Particle Swarm Optimization Technique ◽  
Power Flow Controller ◽  
Generation Control ◽  
Tie Line

In This research PIDF (Proportional Integral Derivative with Filter) is suggested to control the ACE (area control error) signal of automatic generation control circuit (AGC) for two-area multi units system under deregulated conditions, each area consist of two thermal reheat units with physical GRC (generating rate constrain). The parameters of the PIDF controller are tuned using PSO (particle swarm optimization) technique. To improve the system performance, Redox Flow Batteries (RFB) is presented in one area and one of FACTS components IPFC (Inter Line Power Flow Controller) is installed in tie line. The performance of the proposed controller is assessed under different working conditions of deregulated power market. Finally, a comparison will be made on the system response when testing with varying the load conditions and system parameter through MATLAB environment 2015Rb.  

scholarly journals Analysis of work load by computer system response time in different type of VDT tasks

1985 ◽  
Vol 21 (4) ◽  
pp. 211-217 ◽  
Author(s):  
Akinori KOMATSUBARA ◽  
Yoshimi YOKOMIZO ◽  
Sakae YAMAMOTO ◽  
Kageyu NORO
Keyword(s):  
Response Time ◽  
Computer System ◽  
Work Load ◽  
System Response ◽  
System Response Time

scholarly journals Performance Analysis and Optimization Techniques for Oracle Relational Databases

2019 ◽  
Vol 19 (2) ◽  
pp. 117-132
Author(s):  
Fernando Almeida ◽  
Pedro Silva ◽  
Fernando Araújo
Keyword(s):  
Execution Time ◽  
Relational Databases ◽  
Database System ◽  
Optimization Techniques ◽  
Management Systems ◽  
System Response ◽  
Database Access ◽  
Data Manipulation ◽  
System Response Time ◽  
Analyze Data

Abstract Databases provide an efficient way to store, retrieve and analyze data. Oracle relational database is one of the most popular database management systems that is widely used in a different variety of industries and businesses. Therefore, it is important to guarantee that the database access and data manipulation is optimized for reducing database system response time. This paper intends to analyze the performance and the main optimization techniques (Forall, Returning, and Bulk Collect) that can be adopted for Oracle Relational Databases. The results have shown that the adoption of Forall and Bulk Collect approaches bring significant benefits in terms of execution time. Furthermore, the growth rate of the average execution time is lower for Bulk Collect than Forall. However, adoption of Returning approach doesn’t bring significant statistical benefits.

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