Modeling and Simulating of Frequency Conversion Soft Start System Based on SPWM

2014 ◽  
Vol 1049-1050 ◽  
pp. 1102-1106
Author(s):  
Yu Qian Song ◽  
Shou Dong Shi
Keyword(s):  
Frequency Conversion ◽  
Voltage Drop ◽  
Asynchronous Motor ◽  
Sine Wave ◽  
Open Loop ◽  
Loop Control ◽  
Grid Voltage ◽  
Starting Current ◽  
Soft Start ◽  
The Impact

Since over large starting current makes an instant giant grid voltage drop and contacting with current spark can damage the starting device when three phase asynchronous motor is directly started, in order to reduce the impact on the grid and the motor caused by the over large starting current, the present disclosure provides a frequency conversion soft start system based on SPWN. Control system generates IGBT controlled by SPWM pulse control using the regular sampling II method, thus achieving an AC infinitely approaching to a sine wave to open-loop control the motor and implement soft start. The method of frequency conversion soft start based on SPWM may implement a smooth start of the motor with lesser starting current and larger starting torque, thereby largely reducing the impact on the grid voltage and the motor. The experimental results showed that the method of frequency conversion soft start based on SPWM effectively reduces the starting current and implements the motor’s smooth start.

Digital Controller Design for Sense Mode of Micro-Machined Gyroscope

2013 ◽  
Vol 336-338 ◽  
pp. 940-943
Author(s):  
Long Wang ◽  
Chun Hua He ◽  
Yu Xian Liu ◽  
Da Chuan Liu ◽  
Long Tao Lin ◽  
...  
Keyword(s):  
Closed Loop ◽  
Force Feedback ◽  
Sine Wave ◽  
Measurement Range ◽  
Open Loop ◽  
Loop System ◽  
Cordic Algorithm ◽  
Sense Mode ◽  
Wave Source ◽  
Loop Control

This paper presents one kind of digital closed loop control system of MEMS (Micro Electro-Mechanical Systems) vibratory gyroscope, particularly concentrating on the sense mode of MEMS gyroscope. The controller consists of a sine wave source realized by CORDIC algorithm, multiplication demodulators, some low-pass filters and force feedback rebalance module. Compared with the open loop sense system of gyroscope, the closed loop sense system has larger measurement range and wider bandwidth. Besides, the sine wave source realized with CORDIC algorithm can save hardware resources. The digital system is demonstrated on a PCB with a FPGA on it. The test results show that the measurement range of the closed loop system can be increased to 3 times by the open loop, and the bandwidth can be extended to 262Hz from 27Hz of the open loop system.

Open Loop Control of Combustion Instability With a High-Momentum Air-Jet

2004 ◽  
Author(s):  
Jong Ho Uhm ◽  
Sumanta Acharya
Keyword(s):  
Low Frequency ◽  
Sine Wave ◽  
Open Loop ◽  
Effective Control ◽  
High Momentum ◽  
Open Loop Control ◽  
Low Frequencies ◽  
Loop Control ◽  
Wave Modulation ◽  
Air Jet

A new strategy for open-loop control of combustion oscillations using a high-momentum air-jet modulated at low frequencies is presented in this paper. The oscillations in the swirl-stabilized spray combustor of interest are dominated by an acoustic mode (235 Hz) with a low frequency (13 Hz) bulkmode (of the upstream cavity) oscillation superimposed. The most effective strategy for control is shown to be achieved through the use of a new concept which utilizes a high-momentum air-jet injected directly into the region of flame dynamics. It is shown that with a low frequency modulation (15 Hz) of the high momentum air-jet, the pressure oscillations can be reduced significantly (by a factor of nearly 10). Square wave modulation is shown to be considerably more effective than sine-wave modulation. These results are extremely promising since high bandwidth actuation is not required for effective control.

scholarly journals The Impact of Riser-Induced Slugs on the Downstream Deoiling Efficiency

2021 ◽  
Vol 9 (4) ◽  
pp. 391
Author(s):  
Simon Pedersen ◽  
Mads Valentin Bram
Keyword(s):  
Closed Loop ◽  
Oil And Gas ◽  
Separation Efficiency ◽  
Negative Impact ◽  
Open Loop ◽  
Separation Performance ◽  
Operation Condition ◽  
Loop Control ◽  
Pressure Water ◽  
The Impact

In Oil and gas productions, the severe slug is an undesired flow regime due to the negative impact on the production rate and facility safety. This study examines the severe riser-induced slugs’ influence on a typical separation process, consisting of a 3-phase gravity separator physically linked to a deoiling hydrocyclone. Four inflow scenarios are compared: Uncontrolled, open-loop, feasible, and infeasible closed-loop anti-slug control, respectively. Three PID controllers’ coefficients are kept constant for all the tests: The separator pressure, water level, and hydrocyclone pressure-drop-ratio (PDR) controllers. The simulation results show that the separation efficiency is significantly larger in the closed-loop configuration, probably due to the larger production rates which provide a preferable operation condition for the hydrocyclone. It is concluded that both slug elimination approaches improve the separation efficiency consistency, but that the closed-loop control provides the best overall separation performance.

scholarly journals Research and Simulation of Electromagnetic Voltage-Regulated Soft Starter Based on Predictive Control

2018 ◽  
Vol 232 ◽  
pp. 04040
Author(s):  
Xiaoling Chen ◽  
Haihua Li
Keyword(s):  
Predictive Control ◽  
Control Algorithm ◽  
Control Method ◽  
Asynchronous Motor ◽  
Starting Current ◽  
Soft Start ◽  
Soft Starter ◽  
Electromagnetic Control ◽  
Starting Process ◽  
Control Principle

Aiming at the problems of large starting current and unsmooth starting of asynchronous motor, an electromagnetic voltage-regulated soft start control method based on predictive control is proposed. The model of motor soft starter based on predictive control algorithm is established. The control principle of predictive control algorithm is analyzed. The CARIMA model is used to adjust the parameters of motor starting process. With the help of MATLAB, the motor direct start model, the electromagnetic control soft starter model based on PID control algorithm and predictive control algorithm are simulated. The results show that the starting current waveform of the electromagnetic voltage regulator soft starter based on the predictive control algorithm is relatively flat, and the control algorithm can achieve a smooth start of the motor.

scholarly journals Vector Control and Modeling of Modular Multilevel High Voltage Converter for Rail Vehicle Traction

2022 ◽  
Vol 16 ◽  
pp. 517-524
Author(s):  
Yu Zheng ◽  
Changxiu Yang ◽  
Tiefeng Peng ◽  
Liujian Zhang
Keyword(s):  
Vector Control ◽  
High Voltage ◽  
Frequency Conversion ◽  
High Reliability ◽  
Open Loop ◽  
Economic Life ◽  
Traction Motor ◽  
Loop Control ◽  
Rail Vehicle ◽  
Multi Level

Rail transit plays an important role in the social and economic life of China and even all countries in the world, especially some populous countries or regions. The traction drive system of rail vehicle provides three-phase AC with adjustable voltage and frequency for the traction motor, controls the speed and torque of the traction motor, and then controls the operation of the vehicle. The modular multilevel converter has the advantages of low harmonic, good power quality of output waveform, high reliability, no input filtering and power compensation, and is suitable in the field of frequency conversion. In this work, the open-loop scalar control and vector closed-loop control of modular multi-level high-voltage inverter were adopted. It was found that driven by modular multi-level variable frequency vector control system, asynchronous motor not only has less harmonic content of voltage and current waveform, but also its speed regulation characteristics have been improved.

Open-Loop Control of the Precessing Vortex Core in a Swirl-Stabilized Combustor: Impact on Flame Shape and Flame Stability

2018 ◽  
Author(s):  
Finn Lückoff ◽  
Moritz Sieber ◽  
Kilian Oberleithner
Keyword(s):  
Vortex Core ◽  
Open Loop ◽  
Time Resolved ◽  
Loop Control ◽  
Precessing Vortex Core ◽  
Flame Dynamics ◽  
Combustion Properties ◽  
Flame Shape ◽  
Lift Off ◽  
The Impact

In this study, we apply periodic flow excitation of the PVC at the centerbody of a generic swirl-stabilized combustor to investigate the impact of the precessing vortex core (PVC) on flame shape and flame dynamics. Previous studies revealed considerable influence of the PVC on combustion properties such as flame dynamics and fuel/air mixing. We employ time-resolved OH*-chemiluminescence and pressure measurements to investigate the influence of the PVC on flame dynamics and flame shape transition. The PVC is typically present in flames which are detached from the burner outlet. This lift-off is observed for increasingly lean mixtures in this study. With the help of the PVC actuation, studied in this work, the transition point between attached and detached flame is shifted towards richer mixtures. Moreover, the dynamics of heat release rate fluctuations that are related to PVC and thermoacoustic instabilities are extracted from the OH*-chemiluminescence data. This reveals a considerable damping of the thermoacoustic oscillations due to the PVC actuation under technically premixed conditions and the rise of additional modes due to the interaction of both dynamics.

Research on the Control Strategy of DFIG Grid Side Converter under Unbalanced Grid Voltage Conditions

2012 ◽  
Vol 260-261 ◽  
pp. 454-459
Author(s):  
Fei Song ◽  
Dan Zhu ◽  
Kan Tang ◽  
Xue Jing Liu
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Voltage Drop ◽  
Current Control ◽  
Transient Model ◽  
Grid Voltage ◽  
Doubly Fed ◽  
Grid Side ◽  
Grid Side Converter ◽  
The Impact

This paper studies on the electromagnetic transient model of doubly-fed wind turbine grid-side converter under the imbalanced grid condition. And on this basis, the paper analysis the impact of doubly-fed converter when grid voltage asymmetric drop. It puts forward a dual PLL and dual current control combination of doubly-fed converter grid side control strategy. This strategy achieves grid voltage positive and negative sequence fast separation when asymmetric grid voltage drop occur, achieves the active output power secondary fluctuate suppression under the imbalanced grid voltage condition, avoids DC voltage rise at the fault moment and also achieves converter reactive power support under the imbalanced grid fault. The simulation and experimental results show that the proposed control strategy is correct and with the application value of engineering

The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations

2012 ◽  
Vol 220 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Sandra Sülzenbrück
Keyword(s):  
Empirical Research ◽  
Visual Feedback ◽  
Closed Loop ◽  
Motor Planning ◽  
Visual Input ◽  
Closed Loop Control ◽  
Loop Control ◽  
Feedback Type ◽  
Effective Use ◽  
The Impact

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.

Sign in / Sign up

Export Citation Format

Share Document