scholarly journals Study on Zero-Doppler Centroid Control for GEO SAR Ground Observation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yicheng Jiang ◽  
Bin Hu ◽  
Yun Zhang ◽  
Meng Lian ◽  
Zhuoqun Wang
Keyword(s):  
Control Method ◽  
Elliptical Orbit ◽  
Earth Orbit ◽  
New Approach ◽  
Orbital Parameters ◽  
Ground Observation ◽  
The Earth ◽  
Satellite Platform ◽  
Simulation Results ◽  
The Look

In geosynchronous Earth orbit SAR (GEO SAR), Doppler centroid compensation is a key step for imaging process, which could be performed by the attitude steering of a satellite platform. However, this zero-Doppler centroid control method does not work well when the look angle of radar is out of an expected range. This paper primarily analyzes the Doppler properties of GEO SAR in the Earth rectangular coordinate. Then, according to the actual conditions of the GEO SAR ground observation, the effective range is presented by the minimum and maximum possible look angles which are directly related to the orbital parameters. Based on the vector analysis, a new approach for zero-Doppler centroid control in GEO SAR, performing the attitude steering by a combination of pitch and roll rotation, is put forward. This approach, considering the Earth’s rotation and elliptical orbit effects, can accurately reduce the residual Doppler centroid. All the simulation results verify the correctness of the range of look angle and the proposed steering method.

A New Approach to Reduce Engine-Out Emissions Enabled by Trajectory-Based Combustion Control

2015 ◽  
Author(s):  
Chen Zhang ◽  
Zongxuan Sun
Keyword(s):  
Internal Combustion Engines ◽  
Control Method ◽  
Nox Emissions ◽  
Combustion Engines ◽  
Combustion Control ◽  
Ignition Timing ◽  
Free Piston ◽  
New Approach ◽  
Convective Heat Loss ◽  
Simulation Results

Previously, the authors have proposed the concept of piston trajectory-based combustion control enabled by free piston engines (FPE). With this novel control method, the FPE realizes in-cycle real-time combustion control, in terms of adjusting the ignition timing and manipulating the in-cylinder temperature trace, through various piston trajectories and achieves higher thermal efficiency compared to the conventional internal combustion engines. In this paper, the effects of this new combustion control on engine-out emissions are studied. First, a model is developed that includes different piston trajectories in the FPE, a convective heat loss sub model and a reduced n-heptane reaction mechanism with major emissions species from diesel engines. Afterwards, a new approach which reduces the engine-out emissions by employing novel piston trajectories is described. At last, analyses of the simulation results demonstrating the variable piston trajectories’ effects on CO and NOx emissions are presented, which further reveal the advantages of the trajectory-based combustion control.

Coordinated optimization control of shield machine based on dynamic fuzzy neural network direct inverse control

2020 ◽  
pp. 014233122098027
Author(s):  
Xuanyu Liu ◽  
Wentao Wang ◽  
Yudong Wang ◽  
Cheng Shao ◽  
Qiumei Cong
Keyword(s):  
Fuzzy Neural Network ◽  
Control Method ◽  
Earth Pressure ◽  
Screw Conveyor ◽  
Inverse Control ◽  
The Earth ◽  
Coordinated Optimization ◽  
Optimization Control ◽  
Fuzzy Neural ◽  
Shield Machine

During shield machine tunneling, the earth pressure in the sealed cabin must be kept balanced to ensure construction safety. As there is a strong nonlinear coupling relationship among the tunneling parameters, it is difficult to control the balance between the amount of soil entered and the amount discharged in the sealed cabin. So, the control effect of excavation face stability is poor. For this purpose, a coordinated optimization control method of shield machine based on dynamic fuzzy neural network (D-FNN) direct inverse control is proposed. The cutter head torque, advance speed, thrust, screw conveyor speed and earth pressure difference in the sealed cabin are selected as inputs, and the D-FNN control model of the control parameters is established, whose output are screw conveyor speed and advance speed at the next moment. The error reduction rate method is introduced to trim and identify the network structure to optimize the control model. On this basis, an optimal control system for earth pressure balance (EPB) of shield machine is established based on the direct inverse control method. The simulation results show that the method can optimize the control parameters coordinately according to the changes of the construction environment, effectively reduce the earth pressure fluctuations during shield tunneling, and can better control the stability of the excavation surface.

Intelligent Information of TS Fuzzy PID Control System of BLDCM

2013 ◽  
Vol 846-847 ◽  
pp. 313-316 ◽  
Author(s):  
Xiao Yun Zhang
Keyword(s):  
Control System ◽  
Dynamic Model ◽  
Pid Control ◽  
Control Method ◽  
Design Method ◽  
Fuzzy Pid ◽  
Fuzzy Pid Control ◽  
Control Precision ◽  
Simulation Results ◽  
Intelligent Information

This paper presented a new method based on the Fuzzy self - adaptive PID for BLDCM. This method overcomes some defects of the traditional PID control. Such as lower control precision and worse anti - jamming performance. It dynamic model of BLDCM was built, and then design method for TS fuzzy PID model is given, At last, it compared simulation results of PID control method with TS Fuzzy PID control method. The results show that the TS Fuzzy PID control method has more excellent dynamic antistatic performances, as well as anti-jamming performance. The experiment shows that TS fuzzy PID control has the stronger adaptability robustness and transplant.

Study on Direct Torque Control Applied in the Electrical Propulsion Ship

2011 ◽  
Vol 354-355 ◽  
pp. 1252-1256
Author(s):  
You Tao Zhao ◽  
Yan Cheng Liu ◽  
Jun Jie Ren
Keyword(s):  
Electric Propulsion ◽  
Control Method ◽  
Direct Torque Control ◽  
Torque Control ◽  
Regulation System ◽  
Propulsion Systems ◽  
Speed Regulation ◽  
Imple Mentation ◽  
Electrical Propulsion ◽  
Simulation Results

With the development of AC (alternating current )technique, larger power PMSM ( permanent m- agnet synchronous motor ) has been applied in the marine electric propulsion systems. In this paper the imple- mentation of the DTC (direct torque control) systems for a variable-speed 4088kW PMSM in ship electric propulsion systems has been studied. A novel control method using SVPWM (space vector pulse width mo- dulation) was proposed and a SVPWM module was designed. Then a DTC – SVPWM simulation model of PMSM with the load of propeller was found. The simulation results shows that the variable frequency speed regulation system have good response performance in the process of the motor start or speedup and through comparing the simulation results with the experiment data of the PMSM, the validity of the model is verified.

Decoding Digital Information from the Cascaded Heterogeneous Chaotic Systems

2003 ◽  
Vol 13 (06) ◽  
pp. 1599-1608 ◽  
Author(s):  
Chao Tao ◽  
Gonghuan Du ◽  
Yu Zhang
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Chaotic Systems ◽  
Digital Information ◽  
Chaotic Communication ◽  
New Approach ◽  
Communication Scheme ◽  
Simulation Results

In this paper, we propose a new approach to breaking down chaotic communication scheme by attacking its encryption keys. A remarkable advancement is that it can decode the hidden message exactly. This makes it become possible to break down some cascaded chaotic communication systems. We also decode digital information from the cascaded heterogeneous chaotic communication system and give the simulation results.

scholarly journals Control method for the stable operation of distributed inverters following the introduction of large-scale renewable energy to a remote island grid

Clean Energy ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 196-207
Author(s):  
Shoichi Sato ◽  
Yasuhiro Noro
Keyword(s):  
Renewable Energy ◽  
Large Scale ◽  
Control Method ◽  
Synchronous Generator ◽  
Stable Operation ◽  
Battery Energy Storage Systems ◽  
Simulation Results ◽  
Battery Energy ◽  
Systems Simulation ◽  
Different Characteristics

Abstract The introduction of large-scale renewable energy requires a control system that can operate multiple distributed inverters in a stable way. This study proposes an inverter control method that uses information corresponding to the inertia of the synchronous generator to coordinate the operation of battery energy storage systems. Simulation results for a system with multiple inverters applying the control method are presented. Various faults such as line-to-line short circuits and three-phase line-to-ground faults were simulated. Two fault points with different characteristics were compared. The voltage, frequency and active power quickly returned to their steady-state values after the fault was eliminated. From the obtained simulation results, it was verified that our control method can be operated stably against various faults.

scholarly journals Time-Varying Impedance Control of Port Hamiltonian System with a New Energy-Storing Tank

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Min Zheng ◽  
Tangqing Yuan ◽  
Tao Huang
Keyword(s):  
Control Method ◽  
Impedance Control ◽  
Conservative System ◽  
Time Varying ◽  
Control Performance ◽  
Singularity Problem ◽  
Numerical Examples ◽  
New Energy ◽  
Simulation Results ◽  
New Framework

In order to guarantee the passivity of a kind of conservative system, the port Hamiltonian framework combined with a new energy tank is proposed in this paper. A time-varying impedance controller is designed based on this new framework. The time-varying impedance control method is an extension of conventional impedance control and overcomes the singularity problem that existed in the traditional form of energy tank. The validity of the controller designed in this paper is shown by numerical examples. The simulation results show that the proposed controller can not only eliminate the singularity problem but can also improve the control performance.

Simulation and Research of Dynamic Voltage Detection and Regulator Based on MATLAB

2014 ◽  
Vol 536-537 ◽  
pp. 1527-1531
Author(s):  
Ya Feng Li ◽  
Zi Wei Zheng
Keyword(s):  
Theoretical Analysis ◽  
Reactive Power ◽  
Voltage Regulator ◽  
New Approach ◽  
Dynamic Voltage ◽  
Harmonic Voltage ◽  
Simulation Results ◽  
Harmonic Source ◽  
Detecting Method ◽  
Dynamic Voltage Regulator

The Series Dynamic Voltage Regulator can compensate the harmonics distortion caused by voltage type harmonic source This paper presents a new approach of detecting harmonic voltage in dq0 coordinates, based on the generalized instantaneous reactive power ,and used in the series dynamic voltage regulator successfully. It is demonstrated by theoretical analysis and simulation results that the proposed detecting method of harmonic voltage is correct and valid.

An Inverter can be Used in Hybrid Wind-Solar Grid-Connected Power System

2012 ◽  
Vol 512-515 ◽  
pp. 70-73 ◽  
Author(s):  
Yang Tian ◽  
Ru Cheng Han ◽  
Chen Li
Keyword(s):  
Global Warming ◽  
Power System ◽  
Sustainable Energy ◽  
Future Generations ◽  
Energy Sources ◽  
Grid Security ◽  
Operational Analysis ◽  
Harmonic Content ◽  
The Earth ◽  
Simulation Results

With increasing concern of global warming, many are looking at sustainable energy solutions to protect the earth for the future generations.. This paper presents a new inverter which can be used in hybrid wind/photovoltaic grid-connected power system. This inverter allows the two sources to work separately or simultaneously depending on the availability of the energy sources. Harmonic content is detrimental for the Grid security. The introduction of the inverter can effectively reduce the harmonics generated by the system. Operational analysis of the proposed system will be discussed in this paper. Simulation results are given to highlight the merits of the proposed inverter.

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