scholarly journals Dynamic Performance Assessment of Primary Frequency Modulation for a Power Control System Based on MATLAB

Processes ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 11 ◽  
Author(s):  
Shizhe Li ◽  
Yinsong Wang

The primary frequency modulation (PFM) performance of a power control system (PCS) is an important factor affecting the security and stability of a power grid. The traditional control method is proportional integral (PI) control. In order to improve its dynamic control performance, a control method based on the combination of internal model control (IMC) and PI is proposed. Using the method of theoretical assessment and system identification, a simple simulated model of the typical PCS is established. According to the principle of system identification and the least square estimation (LSE) algorithm, the mathematical models of a generator and a built-in model are established. According to the four dynamic performance indexes, the main and auxiliary assessment index of the PCS are defined, and the benchmark and the result of the performance assessment are given. According to three different structures, the PFM dynamic performance of the PCS is analyzed separately. According to the dynamic performance assessment index of PFM, the structure of the control system and the influence of different parameters on the performance of the PCS are analyzed under ideal conditions. The appropriate control structure and controller parameters are determined. Secondly, under the non-ideal condition, the influence of the actual valve flow coefficient on the performance of the control system is studied under two different valve control modes. The simulation results show that the internal model combined with PI has better dynamic control performance and stronger robustness than the traditional PI control, and it also has better application prospects for thermal power plants.

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 65
Author(s):  
Der-Fa Chen ◽  
Shen-Pao-Chi Chiu ◽  
An-Bang Cheng ◽  
Jung-Chu Ting

Electromagnetic actuator systems composed of an induction servo motor (ISM) drive system and a rice milling machine system have widely been used in agricultural applications. In order to achieve a finer control performance, a witty control system using a revised recurrent Jacobi polynomial neural network (RRJPNN) control and two remunerated controls with an altered bat search algorithm (ABSA) method is proposed to control electromagnetic actuator systems. The witty control system with finer learning capability can fulfill the RRJPNN control, which involves an attunement law, two remunerated controls, which have two evaluation laws, and a dominator control. Based on the Lyapunov stability principle, the attunement law in the RRJPNN control and two evaluation laws in the two remunerated controls are derived. Moreover, the ABSA method can acquire the adjustable learning rates to quicken convergence of weights. Finally, the proposed control method exhibits a finer control performance that is confirmed by experimental results.


2010 ◽  
Vol 136 ◽  
pp. 153-157
Author(s):  
Yu Hong Du ◽  
Xiu Ming Jiang ◽  
Xiu Ren Li

To solve the problem of detecting the permeability of the textile machinery, a dedicated test system has been developed based on the pressure difference measuring method. The established system has a number of advantages including simple, fast and accurate. The mathematical model of influencing factors for permeability is derived based on fluid theory, and the relationship of these parameters is achieved. Further investigations are directed towards the inherent characteristics of the control system. Based on the established model and measuring features, an information fusion based clustering control system is proposed to implement the measurement. Using this mechanical structure, a PID control system and a cluster control system have been developed. Simulation and experimental tests are carried out to examine the performance of the established system. It is noted that the clustering method has a high dynamic performance and control accuracy. This cluster fusion control method has been successfully utilized in powder metallurgy collar permeability testing.


Author(s):  
Zheng Chen ◽  
Leslie Cargill ◽  
Brent Naizer

Hydraulic fracturing is one of the key technologies for producing shale oil and gas. During hydraulic fracturing, a blender is used to mix sand with water and chemicals to obtain a fluidic mixture that will be pumped down a well to frack rocks. In order to achieve high-quality fracturing during a job, the blender needs to maintain its tub level as well as the density of the fluidic mixture. In this paper, an auto-tuning proportional-integral (PI) control is developed for the blender automation system to maintain the tub level of its fluidic mixture. The control system adopts a single-loop PI with gains that can be auto-tuned during a job. A relay feedback test is conducted for auto-tuning the PI gains online. The auto-tuning PI control has been successfully tested in a blender simulator. Experimental results have shown that the control performance was improved after auto-tuning and that the control system was adaptive to variation in system parameters.


Author(s):  
Mahmood Lahroodi ◽  
A. A. Mozafari

Neural networks have been applied very successfully in the identification and control of dynamic systems. When designing a control system to ensure the safe and automatic operation of the gas turbine combustor, it is necessary to be able to predict temperature and pressure levels and outlet flow rate throughout the gas turbine combustor to use them for selection of control parameters. This paper describes a nonlinear SVFAC controller scheme for gas turbine combustor. In order to achieve the satisfied control performance, we have to consider the affection of nonlinear factors contained in controller. The neural network controller learns to produce the input selected by the optimization process. The controller is adaptively trained to force the plant output to track a reference output. Proposed Adaptive control system configuration uses two neural networks: a controller network and a model network. The model network is used to predict the effect of controller changes on plant output, which allows the updating of controller parameters. This paper presents the new adaptive SFVC controller using neural networks with compensation for nonlinear plants. The control performance of designed controller is compared with inverse control method and results have shown that the proposed method has good performance for nonlinear plants such as gas turbine combustor.


Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 895
Author(s):  
Mingming Song ◽  
Hongmin Liu ◽  
Yanghuan Xu ◽  
Dongcheng Wang ◽  
Yangyang Huang

Flatness control system is characterized by multi-parameters, strong coupling, pure time delay, which complicate the establishment of an accurate mathematical model. Therefore, a control scheme that combines dynamic decoupling, PI (Proportion and Integral) control and adaptive Smith predictive compensation is proposed. To this end, a dynamic matrix is used to decouple the control system. A multivariable coupled pure time-delay system is transformed into several independent generalized single-loop pure time-delay systems. Then, a PI-adaptive Smith predictive controller is constructed for the decoupled generalized single-loop pure time-delay system. Simulations show that the scheme has a simple and feasible structure, and good control performance. When the mathematical model of the control system is inaccurate, the control performance of adaptive Smith control method is evidently better than that of the ordinary Smith control method. The model is successfully applied to the cold rolling production site through LabVIEW, and the control accuracy is within 5I. This study reveals a new solution to the problem of coupled pure time-delay in flatness control system.


2019 ◽  
Vol 9 (22) ◽  
pp. 4958 ◽  
Author(s):  
Lichuan Zhang ◽  
Lu Liu ◽  
Shuo Zhang ◽  
Sheng Cao

The application of Autonomous Underwater Vehicle (AUV) is expanding rapidly, which drives the urgent need of its autonomy improvement. Motion control system is one of the keys to improve the control and decision-making ability of AUVs. In this paper, a saturation based nonlinear fractional-order PD (FOPD) controller is proposed for AUV motion control. The proposed controller is can achieve better dynamic performance as well as robustness compared with traditional PID type controller. It also has the advantages of simple structure, easy adjustment and easy implementation. The stability of the AUV motion control system with the proposed controller is analyzed through Lyapunov method. Moreover, the controlled performance can also be adjusted to satisfy different control requirements. The outperformed dynamic control performance of AUV yaw and depth systems with the proposed controller is shown by the set-point regulation and trajectory tracking simulation examples.


2014 ◽  
Vol 518 ◽  
pp. 310-315 ◽  
Author(s):  
Hui Wang ◽  
Li Rui Wan ◽  
Cai Dong Wang

In order to further improve on the static and dynamic performance of the permanent magnet linear synchronous motor (PMLSM) speed regulating system, the traditional PI control is combined with the fuzzy control to achieve PI parameters self-regulating. In this paper, on the basis of studying the mathematic model of PMLSM, the resisting integral saturation method are adopted to eliminate the integral saturation which the traditional PI causes. the fuzzy control is introduced into the PI control to realize to the self-optimization of the PI parameters. The simulation results show the resisting integral saturation PI control system based on the fuzzy control algorithm has better static and dynamic performances and stability, and possesses stronger anti-strike performance. Therefore, the new control system resolves the problems which the traditional PI controller cant achieve the most optimization because of the difficulty of the parameter regulating.


2010 ◽  
Vol 139-141 ◽  
pp. 1929-1932
Author(s):  
Cheng Wang ◽  
Bing Yi Li

Aiming at the shortcoming of the integral accumulation in the process of CVT ratio adjusting control, which is caused by the general PID control method, a new ratio adjusting control system based on the shift integral PID control method was designed. The theory of CVT ratio adjusting process and the enhanced control method were analized. The enhanced PID parameter tuning principle was presented. The test-bed of CVT ratio adjusting control was devised and adopted to do the CVT ratio tracing experiments. The experiments of step ratio from 0.45 to 1.45 and from 1.7 to 0.7 were made. The experimental results proved that the new ratio adjusting control system and the enhanced PID parameter tuning principle were valid, which made the real ratio trace the object ratio rapidly and steadily. The control performance of CVT ratio adjusting was improved.


2014 ◽  
Vol 621 ◽  
pp. 462-469 ◽  
Author(s):  
Ming Zhu Zhang ◽  
Zhi Li Zhou

To develop the control system of multi-range hydro-mechanical continuously variable transmission (HMCVT), a model of a multi-range HMCVT is built using the principle of dynamics. According to the characteristic of power split, HMCVT is separated as axes set, variable displacement pump-motor system, clutch set. With wheel tractor as application instance, the whole model of vehicle power train is made, which includes the engine, HMCVT, running system and control system. Based on the theory of Finite State Machine, an automatic control method of speed change and range shift is present, which employs the throttle value, engine speed, range number and transmission ratio as the control parameters. The dynamic characteristic of automatic speed changing and ranges shifting is simulated. The result indicates that the model can correctly represent the dynamic characteristic of HMCVT, the engine can run at the optimal working point, the multi-range HMCVT can shift range steadily and change transmission ratio continuously when the load changes, the circularly shift range is avoided. The model can be used conveniently for the analysis of vehicle dynamic performance and the research of multi-range HMCVT control method.


Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 264
Author(s):  
Meiying Jiang ◽  
Beiyan Jiang ◽  
Qi Wang

It is a challenge to design a satisfactory controller for a complex multivariable industrial system with minimal offsetting and a slow response. An internal model control method is proposed for rank-deficient systems with a time delay based on a damped pseudo-inverse. An internal model control was designed to obtain the desired dynamic characteristics of the system by transforming the time-delay system into a system without a time delay, following the Pade approximation approach. By introducing a damping factor, the internal model controller was designed based on a damped pseudo-inverse, since the inverse matrix of the rank-deficient system does not exist. Furthermore, a singular value decomposition was used to analyze the steady-state performance of the system. The selection of the damping factor was also presented, and a μ analysis was made to evaluate the stability of the system. To demonstrate the effectiveness of the proposed method, a crude distillation process with five inputs and four outputs was considered as an example. The simulation results illustrate that not only can the proposed strategy guarantee the system’s stability, but it also has a relatively good dynamic performance.


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