scholarly journals Advanced automated emergency control strategy for embedded VSC-HVDC links

2020 ◽  
Vol 137 (8) ◽  
pp. 394-399
Author(s):  
Stefan Polster ◽  
Herwig Renner ◽  
Katrin Friedl ◽  
Olof Samuelsson
Keyword(s):  
Control Strategy ◽  
Voltage Stability ◽  
Control Strategies ◽  
Test System ◽  
Emergency Control ◽  
Simple Demonstration ◽  
Simulation Results ◽  
The Impact

AbstractThis paper proposes an advanced emergency control strategy for embedded VSC-HVDC links after AC disturbances, such as line tripping and generation loss. The control goals are to minimize the impact of the disturbance on the AC-network, which includes improving the long-term voltage stability with utilizing possible unloading capacity of parallel AC elements. The proposed algorithm is evaluated against other control strategies for embedded VSC-HVDC links by applying it to a simple demonstration network. The test system includes all necessary VSC converter dynamics, the VSC-HVDC link current and voltage limits and simple load recovery characteristics for an evaluation of the long term voltage stability. The simulation results are explained and the advantages of the proposed emergency control strategy are discussed.

Dual Clutch Automatic Transmission Two Clutch Starting Control and Simulation

2013 ◽  
Vol 372 ◽  
pp. 538-542
Author(s):  
Guo Zhong Jia ◽  
Xin Ping Wu ◽  
Zhen Hua Jia
Keyword(s):  
Simulation Model ◽  
Control Strategy ◽  
Control Strategies ◽  
Automatic Transmission ◽  
Control Model ◽  
Launch Strategy ◽  
Simulation Results ◽  
Clutch Control ◽  
The Impact ◽  
Starting Control

According to the special structure of DCT, the control strategy of launch with two clutches has been proposed to share the friction work and extend the life of both clutches. The dynamic model of launch with two clutches and the clutch control model have been built. the control strategies of both clutches have been proposed respectively according to the requirement of the different driver intention and the limitation of the impact of vehicle. The simulation model of launch with two clutches has been built using the Matlab/Simulink platform, and the simulation has been carried out. The Simulation results show that the balance of friction work based on this launch strategy with two clutches has been validated.

scholarly journals An Investigation Of The Performance Of District Heating Substations Using Computer Simulation

2021 ◽  
Author(s):  
Edmund Wong
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Temperature Drop ◽  
District Heating ◽  
Computational Tool ◽  
Energy Conserving ◽  
Simulation Results ◽  
Operation Parameters ◽  
The Impact ◽  
Industry Professionals

Low primary temperature drop across district heating substations is an undesirable phenomenon observed in the district heating industry. Professionals in the industry have argued that this is caused by inappropriate sizing and controls of district heating substations. The thesis aims to investigate the impact of design and operation parameters on the performance of district heating substations, so that building designers and engineers can potentially better design and operate new and existing district heating substations. The thesis shows that, by developing and using a physical model as a computational tool for sensitivity analysis, different design and operation parameters can be evaluated. This generates insights for energy conserving control strategies to be developed. A preliminary control strategy was proposed for district heating substations, and simulation results show energy saving potentials.

scholarly journals An Investigation Of The Performance Of District Heating Substations Using Computer Simulation

2021 ◽  
Author(s):  
Edmund Wong
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Temperature Drop ◽  
District Heating ◽  
Computational Tool ◽  
Energy Conserving ◽  
Simulation Results ◽  
Operation Parameters ◽  
The Impact ◽  
Industry Professionals

Low primary temperature drop across district heating substations is an undesirable phenomenon observed in the district heating industry. Professionals in the industry have argued that this is caused by inappropriate sizing and controls of district heating substations. The thesis aims to investigate the impact of design and operation parameters on the performance of district heating substations, so that building designers and engineers can potentially better design and operate new and existing district heating substations. The thesis shows that, by developing and using a physical model as a computational tool for sensitivity analysis, different design and operation parameters can be evaluated. This generates insights for energy conserving control strategies to be developed. A preliminary control strategy was proposed for district heating substations, and simulation results show energy saving potentials.

Comprehensive Analysis for Influence of Controllable Damper Time Delay on Semi-Active Suspension Control Strategies

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Yechen Qin ◽  
Feng Zhao ◽  
Zhenfeng Wang ◽  
Liang Gu ◽  
Mingming Dong
Keyword(s):  
Time Delay ◽  
Dynamic Characteristics ◽  
Ride Comfort ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Active Suspension ◽  
Test System ◽  
Suspension Control ◽  
Simulation Results

This paper presents a comprehensive comparison and analysis for the effect of time delay on the five most representative semi-active suspension control strategies, and refers to four unsolved problems related to semi-active suspension performance and delay mechanism that existed. Dynamic characteristics of a commercially available continuous damping control (CDC) damper were first studied, and a material test system (MTS) load frame was used to depict the velocity-force map for a CDC damper. Both inverse and boundary models were developed to determine dynamic characteristics of the damper. In addition, in order for an improper damper delay of the form t+τ to be corrected, a delay mechanism of controllable damper was discussed in detail. Numerical simulation for five control strategies, i.e., modified skyhook control SC, hybrid control (HC), COC, model reference sliding mode control (MRSMC), and integrated error neuro control (IENC), with three different time delays: 5 ms, 10 ms, and 15 ms was performed. Simulation results displayed that by changing control weights/variables, performance of all five control strategies varied from being ride comfort oriented to being road handling oriented. Furthermore, increase in delay time resulted in deterioration of both ride comfort and road handling. Specifically, ride comfort was affected more than road handling. The answers to all four questions were finally provided according to simulation results.

Control of inverters in standalone andgrid-connected microgrid using different control strategies

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vikash Gurugubelli ◽  
Arnab Ghosh
Keyword(s):  
Transient Response ◽  
Control Strategy ◽  
Control Strategies ◽  
Power Balance ◽  
Droop Control ◽  
Content Type ◽  
Simulink Simulation ◽  
Time Simulation ◽  
Simulation Results ◽  
First Time

Purpose The share of renewable energy sources (RESs) in the power system is increasing day by day. The RESs are intermittent, therefore maintaining the grid stability and power balance is very difficult. The purpose of this paper is to control the inverters in microgrid using different control strategies to maintain the system stability and power balance. Design/methodology/approach In this paper, different control strategies are implemented to the voltage source converter (VSC) to get the desired performance. The DQ control is a basic control strategy that is inherently present in the droop and virtual synchronous machine (VSM) control strategies. The droop and VSM control strategies are inspired by the conventional synchronous machine (SM). The main objective of this work is to design and implement the three aforementioned control strategies in microgrid. Findings The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy. Research limitations/implications In the power system, the power electronic-based power allowed by VSM is dominated by the conventional power which is generated from the traditional SM, and then the issues related to stability still need advance study. There are some differences between the SM and VSM characteristics, so the integration of VSM with the existing system still needs further study. Economical operation of VSM with hybrid storage is also one of the future scopes of this work. Originality/value The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy.

scholarly journals Does afforestation deteriorate haze pollution in Beijing–Tianjin–Hebei (BTH), China?

2018 ◽  
Author(s):  
Xin Long ◽  
Naifang Bei ◽  
Jiarui Wu ◽  
Xia Li ◽  
Tian Feng ◽  
...  
Keyword(s):  
Forest Cover ◽  
Fine Particles ◽  
Control Strategies ◽  
Surface Wind ◽  
Forecast Model ◽  
Surface Wind Speed ◽  
Satellite Measurements ◽  
Haze Pollution ◽  
The Impact

Abstract. Although aggressive emission control strategies have been implemented recently in the Beijing–Tianjin–Hebei area (BTH), China, pervasive and persistent haze still frequently engulfs the region during wintertime. Afforestation in BTH, primarily concentrated in the Taihang and Yanshan Mountains, has constituted one of the controversial factors exacerbating the haze pollution due to its slowdown of the surface wind speed. We report here an increasing trend of forest cover in BTH during 2001–2013 based on long-term satellite measurements and the impact of the afforestation on the fine particles (PM2.5) level. Simulations using the Weather Research and Forecast model with chemistry reveal that the afforestation in BTH since 2001 generally deteriorates the haze pollution in BTH to some degree, enhancing PM2.5 concentrations by up to 6 % on average. Complete afforestation or deforestation in the Taihang and Yanshan Mountains would increase or decrease the PM2.5 level within 15 % in BTH. Our model results also suggest that implementing a large ventilation corridor system would not be effective or beneficial to mitigate the haze pollution in Beijing.

Comparison of two control strategies for VSC-MTDC with wind farm

2021 ◽  
Vol 14 ◽  
Author(s):  
Congshan Li ◽  
Pu Zhong ◽  
Ping He ◽  
Yan Liu ◽  
Yan Fang ◽  
...  
Keyword(s):  
Power Control ◽  
Control Strategy ◽  
Voltage Stability ◽  
Wind Farm ◽  
Control Strategies ◽  
Wind Farms ◽  
Active Power ◽  
Stable Operation ◽  
Active Power Control ◽  
Dc Voltage

: Two VSC-MTDC control strategies with different combinations of controllers are proposed to eliminate transient fluctuations in the DC voltage stability, resulting from a power imbalance in a VSC-MTDC connected to wind farms. First, an analysis is performed of a topological model of a VSC converter station and a VSC-MTDC, as well as of a mathematical model of a wind turbine. Then, the principles and characteristics of DC voltage slope control, constant active power control, and inner loop current control used in the VSC-MTDC are introduced. Finally, the PSCAD/EMTDC platform is used to establish an electromagnetic transient model of a wind farm connected to a parallel three-terminal VSC-HVDC. An analysis is performed for three cases of single-phase grounding faults on the rectifier and inverter sides of a converter station and of the withdrawal of the converter station on the rectifier side. Next, the fault response characteristics of VSC-MTDC are compared and analyzed. The simulation results verify the effectiveness of the two control strategies, both of which enable the system to maintain DC voltage stability and active power balance in the event of a fault. Background: The use of a VSC-MTDC to connect wind power to the grid has attracted considerable attention in recent years. A suitable VSC-MTDC control method can enable the stable operation of a power grid. Objective: The study aims to eliminate transient fluctuations in the DC voltage stability resulting from a power imbalance in a VSC-MTDC connected to a wind farm. Method: First, the topological structure and a model of a three-terminal VSC-HVDC system connected to wind farms are studied. Second, an analysis is performed of the outer loop DC voltage slope control, constant active power control and inner loop current control of the converter station of a VSC-MTDC. Two different control strategies are proposed for the parallel three-terminal VSC-HVDC system: the first is DC voltage slope control for the rectifier station and constant active power control for the inverter station, and the second is DC voltage slope control for the inverter station and constant active power for the rectifier station. Finally, a parallel three-terminal VSC-HVDC model is built based on the PSCAD/EMTDC platform and used to verify the accuracy and effectiveness of the proposed control strategy. Results: The results of simulation analysis of the faults on the rectifier and inverter sides of the system show that both strategies can restore the system to the stable operation. The effectiveness of the proposed control strategy is thus verified. Conclusion: The control strategy proposed in this paper provides a technical reference for designing a VSC-MTDC system for wind farms.

Introduction to pertussis transmission and epidemiological dynamics

Pertussis ◽  
2018 ◽  
pp. 6-25
Author(s):  
Pejman Rohani ◽  
Samuel V. Scarpino
Keyword(s):  
Control Strategies ◽  
Age Distribution ◽  
Population Level ◽  
Vaccine Uptake ◽  
Effective Control ◽  
Transmission Potential ◽  
Epidemic Period ◽  
The Impact ◽  
Pertussis Epidemiology

Resolving the long-term, population-level consequences of changes in pertussis epidemiology, arising from bacterial evolution, shifts in vaccine-induced immunity, or changes in surveillance, are key challenges for devising effective control strategies. This chapter reviews some of the key features of pertussis epidemiology, together with the underlying epidemiological principles that set the context for their interpretation. These include the relationship between the age distribution of cases and pertussis transmission potential, the impact of vaccine uptake on incidence, periodicity and age incidence, as well as spatially explicit recurrent pertussis epidemics and associated extinction frequency. This review highlights some of the predictable and consistent aspects of pertussis epidemiology (e.g. the systematic increase in the inter-epidemic period with the introduction of whole-cell vaccines) and a number of important heterogeneities, including variations in contemporary patterns of incidence and geographic spread.

Downshifting Control Strategy for Dual Clutch Transmission With Single Clutch Slippage

2016 ◽  
Author(s):  
Jikai Liu ◽  
Biao Ma ◽  
Heyan Li ◽  
Man Chen ◽  
Jianwen Chen
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Bench Test ◽  
Dual Clutch Transmission ◽  
Pressure Profiles ◽  
Simulation Results ◽  
And Control ◽  
Engagement And Disengagement ◽  
External Loads ◽  
Good Agreement

The cooperation mode between the engagement and disengagement clutches for vehicles equipped with Dual Clutch Transmission (DCT) is of vital importance to achieve a smooth gearshift, in particular for the downshift process as its unavoidable power interruption during the inertia phase. Hence, to elevate the performance of DCT downshifting process, an analytical model and experimental validation for the analysis, simulation and control strategy are presented. Optimized pressure profiles applied on two clutches are obtained based on the detailed analysis of downshifting process. Then, according to the analysis results, a novel control strategy that can achieve downshift task with only one clutch slippage is proposed. The system model is established on Matlab/Simulink platform and used to study the variation of output torque and speed in response to different charging pressure profiles and various external loads during downshifting process. Simulation results show that, compared with conventional control strategies, the proposed one can not only avoid the torque hole and power circulation, but shorten the shift time and reduce the friction work. Furthermore, to validate the effectiveness of the control strategy, the bench test equipped with DCT is conducted and the experiment results show a good agreement with the simulation results.

Sign in / Sign up

Export Citation Format

Share Document