Three-phase grid-connected converters are widely used in renewable and electric power system applications. Due to system nonlinearity and time-variant characteristic, there are limitations in standard decoupled d-q ve...
详细信息
Three-phase grid-connected converters are widely used in renewable and electric power system applications. Due to system nonlinearity and time-variant characteristic, there are limitations in standard decoupled d-q vector control mechanism. To mitigate these limitations, a RNN vector controller trained with Levenberg-Marquardt and FATT(Forward accumulation through time) algorithm is designed. The simulation is researched by using MATLAB software, and the results show that training neural-network algorithm is effective and the system using RNN vector control method outperforms the system using conventional PI control method under low sampling rate conditions.
How to stabilize the output voltage while ensuring the maximum charging efficiency of the system is a problem faced by the development of wireless power transfer(WPT). Especially in the dynamic environment, the change...
详细信息
How to stabilize the output voltage while ensuring the maximum charging efficiency of the system is a problem faced by the development of wireless power transfer(WPT). Especially in the dynamic environment, the change of system coupling coefficient or load resistance will have a huge impact on the system. In this paper, a two-stage DC-DC converter control mode is used to control the system with the goal of dynamic charging demand. Among them, the system achieves impedance matching through the receiver DC-DC converter to ensure the transmission efficiency of the system, and in order to match the impedance, the voltage and current information in the coil is used to calculate the coupling coefficient, then, the coupling coefficient can be used to achieve maximum efficiency. The system output voltage is stabilized by using the transmitter DC-DC converter. The simulation experiment shows that the control mode can stabilize the output voltage well, and is more efficient than the single receiver closed loop control(SRCLP) system.
In the blast furnace,due to the different changing frequency of different operations,and the different reaction time of gas,liquid and solid materials,there exists multi-timescale characteristics in the iron-making **...
详细信息
ISBN:
(纸本)9781538629185
In the blast furnace,due to the different changing frequency of different operations,and the different reaction time of gas,liquid and solid materials,there exists multi-timescale characteristics in the iron-making ***,not enough attention has been paid to this characteristic,most of the analyses on the blast furnace state before are under a fixed time ***,this paper makes a analysis of influencing factors on carbon monoxide utilization rate of blast furnace based on multi-timescale ***,the factors that affect the carbon monoxide utilization rate are analyzed from different time ***,in the short time scale,the individual influencing time scale of the permeability index,total pressure difference and top temperature is found by the support vector machine（SVM） *** in the long time scale,the influencing time scale of burdening is *** the validity of each model is verified by the field data of the blast furnace.
This paper proposes a robust iterative learning control method for the refining furnace alloy weighing process to solve the problem of the poor control accuracy and stability caused by the changing of alloy properties...
详细信息
ISBN:
(纸本)9781538629185
This paper proposes a robust iterative learning control method for the refining furnace alloy weighing process to solve the problem of the poor control accuracy and stability caused by the changing of alloy properties and the frequency of the vibration feeder. First, a two dimensional（2D） weighing model was established based on the analysis of the dynamic characteristics of alloy weighing process. Second, a control scheme is proposed for the 2D model of alloy weighing ***, a robust iterative learning controller is developed and a stability condition of the 2D system is derived through linear matrix inequality（LMI） obtained by a 2D Lyapunov-Krasovskii function. Finally, the simulation results show that the proposed method can sufficiently improve the control precision of the alloy weighing process.
In modern power systems, load frequency control (LFC) scheme usually operates in the discrete mode, while the most existing LFC schemes are designed in the continuous mode, such that those LFC schemes do not work usua...
详细信息
In modern power systems, load frequency control (LFC) scheme usually operates in the discrete mode, while the most existing LFC schemes are designed in the continuous mode, such that those LFC schemes do not work usually in their best manner in practice. In this paper, a method of state-feedback controller design of load frequency control (LFC) for one-area system is discussed in continuous-discrete mode via sampled-data control scheme. At first, the model of LFC is constructed in continuous-discrete mode by using the input delay method. Then, a new method is present to design a state-feedback controller. Finally, a case study is given to show the effectiveness and the benefits of the proposed method.
This paper presents an all-solid porous Ag/Ag Cl electric field sensor with ultralow-potential drift for detecting the seafloor electric field signals. The superiority of porous electrode compared with flat electrode ...
详细信息
This paper presents an all-solid porous Ag/Ag Cl electric field sensor with ultralow-potential drift for detecting the seafloor electric field signals. The superiority of porous electrode compared with flat electrode on the polarization stability is expounded, and the technological process using solid state agglomeration in developing the all-solid porous Ag/Ag Cl electrode core are described. Moreover, a new sensor shell is proposed. Numerous parameters, e.g., polarization resistance, self-potential, drift, etc., of the proposed electrode are tested. The experimental results show that the self-potential is less than ± 0.1 m V, the source resistance is less than 0.01Ω, and the drift potential is less than ±5μV/24 h, which indicate the superior performance of the proposed Ag/Ag Cl electric field sensor for marine electric field exploration.
The traditional wired seismograph has disadvantages such as cumbersome cable, complicated wiring, crosstalk and noise between adjacent transmission lines. In addition, the dynamic range of the instrument is small, and...
详细信息
The traditional wired seismograph has disadvantages such as cumbersome cable, complicated wiring, crosstalk and noise between adjacent transmission lines. In addition, the dynamic range of the instrument is small, and the observation of seismic signals is not intuitive, which can not meet the needs of high-precision seismic exploration. In order to solve these problems, the design of distributed three component seismic data acquisition system based on LoRa wireless communication technology is proposed. The system uses LoRa long-distance wireless communication technology and 24 bit Σ-Δ ADC, which realizes long-distance wireless communication and large dynamic range seismic data acquisition. Besides, the system has man-machine interaction interface, which can observe the parameters of seismic waveform in real time and adjust sampling rate directly. The whole circuit has the advantages of simple design, high precision and good stability. To sum up, the design has certain practical value and application prospect.
Aeromagnetic survey is widely used in geophysical exploration because of large exploration range and little limitations on geographical environment. Aiming at the problem using manned aircraft in aeromagnetic survey, ...
详细信息
Aeromagnetic survey is widely used in geophysical exploration because of large exploration range and little limitations on geographical environment. Aiming at the problem using manned aircraft in aeromagnetic survey, an aeromagnetic system of rotor unmanned aerial vehicle(UAV) based on Overhauser sensor is established. It can carry out high-precision geomagnetic measurement with small magnetic interference and omidirection. Firstly, the magnetic interference of rotor UAV is analyzed and the mathematical model is established for software compensation. Next, aeromagnetic magnetometer based on Overhauser sensor is developed. Finally, the least squares is used to estimate the coefficients. The necessity and superiority of allowing for the eddy-current magnetic field is verified by comparing the fitting results. Moreover, the flight test was carried out and the results showed that the improvement ratio was 6.86. The compensation effect of magnetic interference is verified and magnetic anomaly signal is extracted successfully.
An improved equivalent-input-disturbance(EID) approach is presented in this paper to promote the transient performance of disturbance rejection in the control system. A high-gain observer(HGO) is introduced to the con...
详细信息
An improved equivalent-input-disturbance(EID) approach is presented in this paper to promote the transient performance of disturbance rejection in the control system. A high-gain observer(HGO) is introduced to the conventional EID method to accelerate the convergence of state error. This makes the estimated disturbance tracking the exogenous disturbance more quickly and more precisely. First, the configuration of an improved EID-based control system is described. Then, a sufficient stability condition is derived in terms of a linear matrix inequality(LMI). The resulting LMI is used to find the gains of state observer and state feedback controller. Finally, the validity of the devised method and its superiority over a conventional EID method is demonstrated through the simulation of a numerical example.
This paper investigates the problem of Synchronous control of Fractional gene regulatory *** on the Lyapunov stability judgment method,we apply two kinds of control method,adaptive projection control and adaptive slid...
详细信息
ISBN:
(纸本)9781538629185
This paper investigates the problem of Synchronous control of Fractional gene regulatory *** on the Lyapunov stability judgment method,we apply two kinds of control method,adaptive projection control and adaptive sliding mode control,for making system ***,a numerical simulation example is provided to verify the effectiveness and the benefit of the proposed synchronicity criterion.
暂无评论