A study of the frequency converter control method for rotatory screen

2015 ◽  
pp. 365-368
Author(s):  
H. Xu ◽  
J. Zheng ◽  
M.D. Li ◽  
X.S. Che
Keyword(s):  
Control Method ◽  
Frequency Converter

scholarly journals Research and Application of Rubber Tree Quantitative Fertilization System Control Based on PLC

2018 ◽  
Vol 176 ◽  
pp. 01013
Author(s):  
Yeqin Wang ◽  
Yuan Zhang ◽  
Yiguo Deng ◽  
Lijiao Wei ◽  
Shengli Liu
Keyword(s):  
Natural Rubber ◽  
Control Method ◽  
Frequency Converter ◽  
Rubber Tree ◽  
Control Process ◽  
System Control ◽  
Application Process ◽  
Type Selection ◽  
Fertilization System ◽  
Selection Of

In this paper, the quantitative control method and system control process of the natural rubber forest quantitative fertilization system are introduced on the basis of the demand for the quantitative fertilization of natural rubber forest and the application process of the rubber forest fertilizing machine. The selection of PLC, frequency converter type selection and software design process are described in detail.

scholarly journals Vacuum Fluctuation in a 2×3 Tandem Milking Plant in Dependence on the Vacuum Control Method

2016 ◽  
Vol 64 (3) ◽  
pp. 775-779
Author(s):  
Jiří Fryč ◽  
Josef Los ◽  
Radovan Kukla ◽  
Tomáš Lošák ◽  
Kristina Somerlíková
Keyword(s):  
Flow Rate ◽  
Control Method ◽  
Frequency Converter ◽  
Control Valve ◽  
Control Methods ◽  
Vacuum Fluctuation ◽  
Variable Flow

Vacuum fluctuation was measured using three different vacuum control methods. Firstly, the use was made of a control valve delivered by the manufacturer; then, an additionally installed frequency converter was used. Lastly, a frequency converter fitted with the stabilisation device prototype was used. First, the control sensitivity according to ISO was measured in all three alternatives. Then the vacuum fluctuation during milking was measured. To conduct the measurements under objectively identified conditions, another measurement was conducted with the air feed during milking being replaced with a precisely defined variable flow rate. The conducted measurement confirmed the fact that when the frequency converter is used, the vacuum fluctuation in the stabilised condition is at the same level as when the control valve is used. If there are sudden changes in the flow rate and the frequency converter is used, the vacuum fluctuation increases. The proposed stabilisation device prototype can reduce the fluctuation.

scholarly journals Research of Power Control for Grid-connected Wind Turbine with Differential Speed Regulation

2018 ◽  
Author(s):  
Su Rui ◽  
Zhang Huan ◽  
Wang Fujun ◽  
Li Gangjun
Keyword(s):  
Wind Speed ◽  
Power Control ◽  
Wind Turbine ◽  
Control Method ◽  
Frequency Converter ◽  
Gear Train ◽  
Speed Ratio ◽  
Rotor Speed ◽  
Speed Regulation ◽  
Differential Speed

The differential gear train and speed regulating motor constitute the variable ratio transmission for grid-connected wind turbine with differential speed regulation. The synchronous generator in the system can accessing the power grid without frequency converter. The transmission can realize the mode of variable speed constant frequency that the wind rotor speed is varying and the generator rotor speed is constant. The power control method is studied under the different wind speed which is lower or higher than rated wind speed with using the relational expression of utilization rate of wind energy Cp, pitch angle β and the tip speed ratio λ. The SIMULINK software is used to build the 1500 kW wind turbine model with differential speed regulation. Some different wind speed is made as input. The feasibility of power control method for grid-connected wind turbine with differential speed regulation is verified by the comparison between the simulation results and the theoretical value of the key parameters.

scholarly journals Vacuum Fluctuation in 2 × 13 Herringbone Milking Parlour in Dependence on Vacuum Control Method

2015 ◽  
Vol 18 (4) ◽  
pp. 118-121
Author(s):  
Jiří Fryč ◽  
Josef Los ◽  
Radovan Kukla ◽  
Jan Kudělka
Keyword(s):  
Flow Rate ◽  
Control Method ◽  
Frequency Converter ◽  
Control Valve ◽  
Control Methods ◽  
Vacuum Fluctuation ◽  
Variable Flow

Abstract Vacuum fluctuation was measured using three different vacuum control methods. Firstly, the use was made of a control valve delivered by the manufacturer; then, an additionally installed frequency converter was used. Lastly, a frequency converter fitted with the stabilisation device prototype was used. First, control sensitivity according to ISO was measured in all the three alternatives. Then, vacuum fluctuation during milking was measured. To conduct the measurements under objectively identified conditions, another measurement was conducted with air feed during milking being replaced with a precisely defined variable flow rate. The conducted measurement confirmed the fact that when the frequency converter is used, vacuum fluctuation in stabilised condition is at the same level as when the control valve is used. If there are sudden changes in flow rate and the frequency converter is used, vacuum fluctuation increases. The proposed stabilisation device prototype can reduce the fluctuation in small milking plant but it is not suitable in large milking parlours.

scholarly journals Improving Reliability and Energy Efficiency of Three Parallel Pumps by Selecting Trade-Off Operating Points

Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1297
Author(s):  
Safarbek Oshurbekov ◽  
Vadim Kazakbaev ◽  
Vladimir Prakht ◽  
Vladimir Dmitrievskii
Keyword(s):  
Energy Efficiency ◽  
Control Method ◽  
Frequency Converter ◽  
Operating Cycle ◽  
Pump System ◽  
Trade Off ◽  
Pumping System ◽  
System A ◽  
Operating Points ◽  
Maximum Reliability

Reliability, along with energy efficiency, is an important characteristic of pump units in various applications. In practical pump applications, it is important to strike a balance between reliability and energy efficiency. These indicators strongly depend on the applied control method of the pump unit. This study analyzes a trade-off method for regulating a system with three parallel pumps equipped with only one frequency converter (multi-pump single-drive system). A typical operating cycle of a pumping system with variable flow rate requirements is considered. The proposed trade-off method is compared with the traditional regulation, when a change in the operating point of the pump is achieved only by changing the rotation speed, and with the method for maximum reliability. It is shown that the proposed trade-off method makes it possible to ensure sufficient reliability of the multi-pump system operation without a significant increase in energy consumption.

A High-Frequency High-Voltage Excitation Melting Ice Power Design

2013 ◽  
Vol 325-326 ◽  
pp. 271-276 ◽  
Author(s):  
Yu Sheng Zhou ◽  
Long Zeng ◽  
Pei Yao Chen ◽  
Zheng Pan
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
High Frequency ◽  
Frequency Conversion ◽  
Control Method ◽  
Frequency Converter ◽  
Electric Energy ◽  
Notch Filter ◽  
Excitation Power ◽  
Conversion Function

High-frequency and high-voltage excitation melting ice device is mainly composed of the excitation power supply and the notch filter device, which can realize the power transmission line melting ice without power cut. This paper applied power electronic frequency conversion technology to design a excitation melting ice device with 18KV/40KHZ.This device is adopted PWM control technology, and is mainly composed of the rectifier, controller and inverter. For the small frequency converter, the high-voltage frequency conversion function can be achieved through each phase in series divided voltage method. According to the 1000 kV AC ultrahigh voltage transmission lines, a melting ice model is set up by using SIMULINK simulation. The results show that this device can generate stable 18KV/40KHZ excitation melting ice electric energy in 30ms,and the control method is convenient and simple, the range of frequency and voltage modulation is big characteristics.

scholarly journals Highly reliable Coordinated Control Strategy for Static Frequency Converters applied to Large Synchronous Condensers

CONVERTER ◽  
2021 ◽  
pp. 646-657
Author(s):  
Xiangjian Shi, Et al.
Keyword(s):  
Control Method ◽  
Frequency Converter ◽  
Dynamic Change ◽  
Coordinated Control ◽  
Stable Operation ◽  
Peak Reduction ◽  
Frequency Converters ◽  
Grid Synchronization ◽  
Synchronous Condenser ◽  
Grid Side

A large synchronous condenser can quickly and flexibly implement various functions such as dynamic change in load tracking, realization of peak reduction and valley filling, emergency reserve, frequency modulation, and phase modulation. This type of condenser is typically started using a static frequency converter (SFC). Based on the analysis of the working principle of SFCs, this paper proposes a highly reliable coordinated control method with resynchronization criterion for an SFC. An auxiliary loop is introduced for voltage control at the SFC to realize feedforward of the trigger angle of the rectifier. This method can effectively improve the success rate of grid synchronization of the synchronous condenser and shorten the start-up time. Moreover, when the AC voltage on the grid side drops, the auxiliary ring can automatically reduce the terminal voltage to maintain a stable operation. A comparative experiment was conducted on an RTDS to verify the feasibility and effectiveness of the proposed method.

scholarly journals Mathematical Simulation of the Synchronized Asynchronous Electric Drive

2020 ◽  
Vol 178 ◽  
pp. 01021 ◽  
Author(s):  
Victor Meshcheryakov ◽  
Dmitry Sibirtsev ◽  
Ekaterina Mikhailova
Keyword(s):  
Electric Drive ◽  
Control Method ◽  
Frequency Control ◽  
Frequency Converter ◽  
Asynchronous Motor ◽  
Motor Speed ◽  
Ac Drives ◽  
Asynchronous Electric Drive ◽  
Wide Range ◽  
Rotor Winding

At the end of the last century asynchronous motors with a phase rotor were most widely used among adjustable-speed AC drives. They were used for conveyors, transporters, cranes. That was due to the relative simplicity to adjust the motor speed by acting on the rotor chain. The introduction of a frequency control method in such drives is now complicated by the fact that most frequency converters are designed to be used in drives with a cage asynchronous motor. Shorting of a phase winding leads to highly increased losses during acceleration and motor speed control. If the stator winding of a wound-rotor asynchronous motor is connected to a frequency converter and the rotor winding is connected to a DC link of this converter, the motor will have properties of a synchronous one. The electric drive is able to work in a wide range, while motor characteristics are absolutely rigid. The implementation of such control method is presented in this article. The control system operation has been tested with simulation in the Matlab Simulink software pack. The obtained results are defined as follows.

Design of Control System for Automatic Glass Duster

2012 ◽  
Vol 466-467 ◽  
pp. 719-723
Author(s):  
Cai Qiao Wei ◽  
Xiao Guang Wang ◽  
Hui Guo
Keyword(s):  
Control System ◽  
Pid Control ◽  
Control Method ◽  
Frequency Converter ◽  
Touch Screen ◽  
Static Electricity ◽  
System Function ◽  
Safe Storage ◽  
Rotary Speed ◽  
Special Control

A control system was designed in order to endble the glass duster to cooperate harmoniously.The system consisted of PLC,touch screen,frequency converter,moter and other components.The rotary speed of motor was adjusted by the frequency converter to keep dusting powder amounts constance. The static electricity technology was used to increase adsorption of the powder . The PID control method was proposed to meet the special control request of the powder box temperature. The test indicated that the dusting amounts was between 0.4-1.6 grams per square metre. About 85% of powder could adsorb on glass,system function and accuracy could meet the needs of the safe storage and transportation completely.

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