Matlab/Simulink Based Dynamic Simulation System for Distance Protection

To observe the inner operating process of distance protection,a Matlab/Simulink based dynamic simulation system for microprocessor-based distance protection is designed in this paper.As a modularized design,the simulation system is composed of several modules such as fault transient calculation,startup,Fourier algorithm,phase selection,impedance computing and impedance comparison etc.Some typical simulation cases,which focus on the main factors affecting distance relay's operation,have been simulated with the system.Simulation results show that the system is able to demonstrate the dynamic behaviors of distance protection under different operating conditions.

Modelling and Simulation of an Ohmic Heating Process

Ohmic Heating (OH) is one of the emerging thermal technologies used in food processing which can produce rapid and uniform heating with close to 100% energy transfer efficiency. Although mathematical modelling for OH processes has been studied by many researchers in recent years, systematic simulations of OH have not been developed for model-based control of the processes. In this paper, mathematical model for a Colinear Ohmic Heater is presented, analyzed, and studied based on the selected configuration. A numerical solution for the mathematical equations has been defined and proposed. MATLAB/Simulink model is hence developed and validated against the available data. Simulation results have shown that MATLAB/Simulink model can produce robust outputs at low computational costs with an accuracy of up to 99.6% in comparison to the analytical solution. This model can be used in further studies for analysis of the OH processes and development of advanced controllers.

Design of Simulation for Time-Division Multiplexing Digital Optimal Frequency Band Transmission System

This paper designs a simulation experiment model of the overall structure of time-division multiplexing digital optimal frequency band transmission system based on MATLAB simulation platform. The parameters of each module in the simulation model are set. The working process and performance of the time-division multiplexing digital optimal band transmission system are simulated. The simulation results show that the digital optimal band transmission system achieves the best transmission receiving conditions and performance, and the designed time-division multiplexing optimal digital band transmission simulation system achieves its functions. The research in this paper will help to improve the level of digital communication technology and to understand the structure of time-division multiplexing digital optimal band transmission system.

Evaluation of the Performance of Lithium-Ion Accumulators for Photovoltaic Energy Storage

In a context of climate change exacerbated by the increasing scarcity of fossil fuels, renewable energies, in particular photovoltaic solar energy, offer a promising alternative. Solar energy is non-polluting, globally available and the most widely distributed resource on Earth. However, the intermittency of this energy source considerably limits its expansion. To solve this problem, storage techniques are being used, in particular, electrochemical storage using lithium-ion batteries. In this article, we will evaluate the performance of lithium-ion batteries when integrated into a photovoltaic grid. To do this, modelling and simulation of a photovoltaic system connected to a lithium-ion battery storage system will be carried out using MATLAB/Simulink software. A diagnostic of the energy consumption of the Kaya Polytechnic University Centre will be carried out, and the data will then be used in the simulator to observe the behaviour of the PV-Lion system. The results obtained indicate that lithium-ion batteries can effectively meet the centre’s energy demand. In addition, it was observed that lithium-ion batteries perform better under high energy demand than the other battery technologies studied. Successive storage systems with the same capacity but different battery technologies were compared. It was found that these storage systems can handle a maximum power of 4 × 105 W for lead-acid batteries, 6.5 × 105 W for nickel-cadmium batteries, 8.5 × 105 W for nickel-metal-hydride batteries, and more than 10 × 105 W for lithium-ion technology.

Positioning-control Based on Trapezoidal Velocity Curve for High-precision Basis Weight Control Valve

Traditionally, basis weight control valve is driven by a constant frequency pulse signal. Therefore, it is difficult for the valve to match the control precision of basis weight. Dynamic simulation research using Matlab/Simulink indicates that there is much more overshoot and fluctuating during the valve-positioning process. In order to improve the valve-positioning precision, the control method of trapezoidal velocity curve was studied. The simulation result showed that the positioning steady-state error was less than 0.0056%, whereas the peak error was less than 0.016% by using trapezoidal velocity curve at 10 positioning steps. A valve-positioning precision experimental device for the stepper motor of basis weight control valve was developed. The experiment results showed that the error ratio of 1/10000 positioning steps was 4% by using trapezoidal velocity curve. Furthermore, the error ratio of 10/10000 positioning steps was 0.5%. It proved that the valve-positioning precision of trapezoidal velocity curve was much higher than that of the constant frequency pulse signal control strategy. The new control method of trapezoidal velocity curve can satisfy the precision requirement of 10000 steps.

Research of Pure Electric Ferry System and Its Short-Circuit Protection and Calculation

System control and safety reliability are important links of the marine DC (Direct Current) power system. The simulationmodel is built by Matlab/Simulink, the battery and super-capacitor are supplied to the system through a three-phase interleaved DC/DCconverter, the fuse and disconnector switch combination are used as the protection device, and the short-circuit point is set betweeneach branch and the DC distribution board, performing short-circuit simulation. This paper also proposes a short-circuit calculationmethod for super-capacitors based on the simplified model of series RC (Resistors & Capacitors), and verifies its correctness throughsimulation data. The results show that the introduction of a three-phase interleaved DC/DC converter reduces the current ripple andmakes the system control more convenient;short-circuit calculation and simulation have determined the short-circuit withstandcapability of the DC distribution board, and verified the feasibility of the fuse selection method and the short-circuit calculation methodof the super-capacitor. This provides reliable verification for the application and calculation of the actual project.

Simulation for accelerator dynamic power supply based on current-source PWMrectifier

Purpose The booster power supply of high-energy photon source is dynamic power supply,and the output is 2-Hz bias sine wave.Current-source rectifier(CSR)topology can achieve the 2-Hz current directly.Methods In order to get the output current and good power factor of the power grid,the algorithm of“indirect current control”is applied.This method needs to measure the voltage of three phases and calculates several certain parameters of the circuit.The control strategy based on the“indirect current control”of the CSR is built in the Simulink simulation environment.Parameters and algorithms are described in detail,and the control block diagram and simulation model are given.Results The control strategy can output the right current and make a good power factor in the side of grid.Conclusions The CSR topology,as a good choice of power supply of accelerator,has a well-researched prospect.

Electronic control seed-metering system for precision seeding maize based on fuzzy PID

Aiming at the problem of poor uniformity of maize sowing caused by ground wheel slip,an electronic control seed-metering system(ECSMS)for maize single seed precision sowing was designed and a mathematical model for motor control of the ECSMS was determined.The PID parameters were set by Z-N method and fuzzy control.The fuzzy PID control design and Simulink simulation were completed by MATLAB,which reduced response time of the system by 0.23 s and improved the control accuracy.Experiments on the JPS-12 test bench show that the qualification index(QI)of maize seed-metering device with the ECSMS increases by 4.47%,the multiples index(MI)decreases by 1.96%,the miss index(MIX)decreases by 2.81%,and the coefficient of variation(CV)of qualified seed spacing decreases by 5.06%,and the sowing uniformity has been greatly improved.Test results of the soil-tank test bench show that the system has good sowing uniformity and stability.And the QI is 96.74%,the MI is 2.15%,the MIX is 1.10%,and the CV of qualified seed spacing is 16.24%.Under different setting seed spacing and different sowing operation speed,the change range of seeding quality index was within 10%.The results of field sowing test show that the QI was 84.21%,the MI was 2.63%,the MIX was 7.89%,and the CV of qualified seed spacing was 22.15%,which meet the requirements of JB/T 10293-2013‘Specification for single seed planters(precision planters)’and the agronomic requirements for maize precision sowing.The system runs stably and reliably in practical operation and has good operation performance.