Virtual model-based control of vibration machine operation

Doubly fed induction generator (DFIG) wind turbines with virtual inertia control are coupled to power system in dynamic characteristics, and the control input of virtual inertia control is directly affected by the tracking ability of phase-locked loop (PLL). Thus, it is urgent to study the impact of DFIG wind turbines with virtual inertia control on power system small-signal stability considering the effects of PLL. First, based on DFIG operation characteristic and control strategy, a small-signal model of interconnected system with DFIG integration considering PLL and virtual inertial control is established. Second, the attenuation time constants of DFIG state variables are calculated, and according to the attenuation speeds of different state variables and the coupling between them, it is found out that PLL and virtual inertia are the main factors that affect the coupling between DFIG and synchronous generators. And then, considering that both PLL and virtual inertia control will affect the oscillation modes of synchronous generators, analytical method is used to reveal system small-signal stability under the joint effects of the two factors quantitatively. Analysis results show that, for DFIG wind turbines with virtual inertial control, PLL affects system damping mainly by affecting the participation of virtual inertia in the system. The smaller the PI parameters of PLL are, the smaller the participation factor of virtual inertia control state variables in the interarea oscillation mode is, and the bigger the electromechanical oscillation mode damping ratio is. Simulation results verify the reasonableness of the established model and the possibility that virtual inertia control may cause system small-signal stability to deteriorate in multimachine system.

We propose an agent-based virtual enterprise model and provide the agent collaboration mechanisms under the model, thereby achieving agent-based virtual enterprise modeling and operation control. We establish a network of distributed activity agents and resource agents for each member enterprise, collaborations among which can deal with activity precedence arrangements and activity-resource assignments in each sub-business-process. Then, we model each member enterprise in the virtual enterprise as an agent. Collaborations among member enterprise agents can deal with activity coordination and resource sharing among various sub-business-processes. Thus, our agent-based approach achieves distributed control over the whole business process execution of the virtual enterprise.

The complex industrial process is consisted of multiple loops with coupling relation. They have the characteristics of strong nonlinearity and non-stationary. So it is difficult to describe them with precise mathematical models. Thus, the design of control systems about complex industrial process mainly relies on repeated experiments and debugging on the actual system. Moreover, the novel operational optimization control algorithms cannot directly applied to the operation of industrial processes in terms of factors like safety requirement and economic cost. Therefore, it is necessary to build simulation platforms of complex industrial process to solve these issues. In order to construct an effective simulation platform, a review on different simulation platforms is made in this paper. The existing simulation platforms for industrial process are divided into four categories. They are real control system and real controlled object, real control system and virtual controlled object, virtual control system and real controlled object and virtual control system and virtual controlled object. Then, their structure and application background are analyzed in detail. The existing problems are also summarized. Finally, the conclusion and prospect of simulation platforms for industrial process are given out.

To deal with the constrained communication between Device net of device layer and Ethernet of operation layer in industrial processes, a semi-physical simulation platform, which consists of industrial process control system, constrained communication transmission module and virtual process control object, is designed and proposed in this paper. Considering thoroughly the problems of packet dropout, noise and delay in transmission, the platform provides an effective semi-physical verification environment for the further research and development of double layer network-based operational control system. With the modular structure, the platform can separately replace or improve the process model and the operational control algorithm. Furthermore, an operational control method of flotation process is employed to verify the effectiveness and feasibility of secondary development of the platform.

With the advancements of automation technologies, factory operations have shifted from labor-based to semi-automatic and fully automatic and may even become unmanned in the future. Therefore, the conditions of a factory can be monitored from a distance and the machines can be remotely controlled. This study investigated the predictive distant operation of a computer numerical control (CNC) machine virtually controlled with hand gestures. Similar previous studies were conducted only involving robotic arms. Nevertheless, the attempt in this study is a crucial step toward entirely Internet- or cloud-based manufacturing. In the proposed methodology, meaningful hand gestures corresponding to eight commonly used CNC operations were established. Kinect was then used to track the skeletal information of an operator, and based on this information, the joint angles of the operator were derived using the space vector method. Four rules were then proposed to predict the hand gesture of the operator according to the changes of the joint angles when making the hand gestures to control the CNC machine. An experimental system was established to demonstrate the applicability of the proposed methodology. According to the experimental results, the eight hand gestures were recognized with favorable accuracy. In addition, analysis of variance was performed and the results indicated that the performance of the proposed methodology is robust to the operators' differences.

Coordination between protection and control devices is crucial for maintaining continuous operation of power systems. Existing strategies suffer from improper coordination of control and protection devices. Moreover, high penetration levels of renewable energy sources result in lowering the overall power system inertia. Therefore, this paper presents a robust fuzzy‐logic control (FLC) method for superconducting magnetic energy storage (SMES) in low inertia power systems. The new proposed FLC enables robust and wide operating range for SMES compared to the widely employed controllers. The proposed FLC method and load frequency control are coordinated to emulate virtual inertia. In addition, a cooperate coordination between frequency relay and proposed controller is preserved to maintain reliable operation of low inertia power systems. To prove the effectiveness of proposed coordination strategy, it has been tested with considering different load and renewable energy sources (RESs) disturbances with varying inertia level of the selected case study. The results demonstrate that the proposed FLC method can achieve robust SMES operation as virtual inertia controller (VIC) at wide operating range. Moreover, cooperative operation of VIC and frequency protection is preserved using the proposed coordination strategy. The power system availability, frequency regulation, and dynamic stability are improved using the proposed method.

This article proposes an adaptive virtual inertia control system for stable operation of microgrids: it theoretically improves recent related results in the literature. The overall control system is conceived to provide ancillary services support (namely, enhanced frequency regulation with inertial response and voltage support) to an ac/dc microgrid that consists of a dc bus providing power to the ac one, being, in turn, composed of a diesel generator and loads. The ac voltages and currents are controlled via a nonlinear algorithm based on control-induced time-scale separation and singular perturbation analysis, whose use greatly simplifies the control design and the choice of the tuning gains, when compared with the classical linear controls. With the aim of reducing oscillations from the grid by assuring suitable short circuit ratio (SCR) and proper $X/R$ characteristics, a virtual impedance is also implemented, along with frequency and voltage droops: they constitute high-level controllers that give references to the virtual inertia scheme and compose a comprehensive control. Detailed simulations illustrate, in different relevant settings, the performance of the proposed scheme.

The EUROCONTROL airport operations programme (APR) is providing stakeholders with documentation and support for safe, cost-effective and efficient airport operations. Within this work programme the potential of advanced surface movement guidance and control systems (A-SMGCS) to increase safety and maintain throughput in all weather conditions is investigated. Currently, airport operations under low visibility conditions are still based on procedures and working methods without automation support. National Aerospace Laboratory of the Netherlands (NLR) together with their partners from the German Aerospace Centre (DLR) carried out research activities on the selection and evaluation of candidate concepts for advanced operations with A-SMGCS surveillance under low visibility conditions as part of the EUROCONTROL APR. During dedicated interviews and workshops with stakeholders, candidate concepts were selected based on criteria for usability, safety, human factors, and cost-benefit. Two candidate concepts, named virtual block control and separation bubble alerting, emerged and were evaluated in full-scale human-in-the-loop real-time simulations of Rotterdam Airport on the NLR ATM Research Tower Simulator (NARSIM Tower) platform. The study showed that a combination of the two tower control concepts can indeed improve efficiency of operations under low visibility conditions. The designed interface prototypes are flexible and inexpensive tools that should be developed further.

Virtual control, replicas and decomposition of operators

In the case of flexible HVDC transmission system supplying power to passive island power grid, the inertia of receiving end system is small, and it is difficult for inverters to provide frequency support for it. Therefore, it is necessary to study and improve its control mode. According to the concept of virtual synchronous generator, a control method which can simulate the operation characteristics of synchronous generator is proposed. It can provide virtual moment of inertia for the system. In this paper, an improved virtual synchronous machine controller is designed by simulating the inverting side of flexible HVDC system as synchronous generator operation and traditional virtual synchronous machine control. A detailed model of flexible HVDC transmission system is built in PSCAD/EMTDC, and digital simulation is carried out for normal working condition and abrupt change of load power. Under different operating conditions, the system is simulated with inner and outer loop control, VSG and improved virtual synchronous machine control. The simulation results show that the control strategy of virtual synchronous machine can provide strong frequency support for the system.

This paper considers the utility of VR in the design of the interface to a space-based telerobotic manipulator. An experiment was conducted to evaluate the potential for improved operator performance in a telemanipulation task when the operator's control interface was varied between egocentric and exocentric frames of reference (FOR). Participants performed three tasks of increasing difficulty using a VR-based simulation of the Space Shuttle Remote Manipulation System (SRMS) under four different control interface conditions, which varied in respect of two factors, virtual viewpoint FOR (fixed versus attached to arm) and hand controller FOR (end-effector-referenced versus world-referenced.) Results indicated a high degree of interaction between spatial properties of the task and the optimal interface condition. Across all tasks, the conditions under end-effector-referenced control were associated with higher performance, as measured by rate of task completion. The mobile viewpoint conditions were generally associated with lower performance on task completion rate but improved performance with respect to number of collisions between the arm and objects in the environment. We conclude with discussion of implications for telemanipulation applications, and an approach to varying the dimension of viewpoint egocentricity in order to improve performance under the mobile viewpoint.

Global operation and system control are important issues in massively parallel systems. The paper discusses virtual control networks (VCNs), which are substitutes for the current dedicated control networks. First we introduce a new mechanism called Virtual Control Channel (VCC) used to conduct control information over data network links. The network nodes have control finite state machines (CFSMs) and a VCN is composed of CFSMs. The VCC performs the role of a connection wire between CFSMs. The mechanisms are applied to the RWC-1 machine. The simulation results reveal that reduction and broadcasting operations are efficiently executed on VCNs by exploiting the tree structure.

Oxygen sensor is an important measurement device of the automobile that is utilized to detect the oxygen concentration of automobile exhaust. The measuring precise mainly depends on the performance of the oxygen sensor controller. In this paper, the essential operating principle and controller design of the wide rang oxygen sensor have been introduced. According to the characteristics of the object and the control performance requirement, PID control algorithm is introduced to control temperature and the pumping cell. A simulink control model is built based on the Dspace real-time simulation platform, the control model in the matlab can be used as an virtual controller which can be combined with real object to form closed loop control system, a real time simulation is conducted. Optimization of the control algorithm can be made based on the simulation result. The working performance of the oxygen sensor can satisfy the requirement of practical application under the relative optimal algorithm, and the measurement accuracy is acceptable. At the same time, a streamlined and efficient control C code is generated by TargetLink Software,which can be used to embedded development for designing real controller.

Soft open point (SOP) mostly adopts “rigid” control strategy, which is insufficient with inertia and damping. It leads to the lack of flexibility in feeder power flow control and cannot actively participate in power adjustment of the distribution network. In addition, SOP mostly relies on feeder power to stabilize the DC bus voltage, which greatly limits the flexibility and operational reliability of feeder power flow control in distribution network. In this paper, a self-energy storage soft open point (SES-SOP) operation control strategy is proposed to solve the aforementioned problems. The AC and DC ports of the SESSOP are integrated with a unified virtual motor control, and the operating characteristics of the rotating electric machinery are simulated simultaneously on both ports, and there is no need to switch control strategies during multi-mode operation. The DC port exhibits flexible characteristics, suppresses the impulsion of the feeder exchange power to the DC bus voltage, and enhances the inertia and stability of the DC bus voltage. At the same time, the active and reactive power of the port can be adjusted actively to support the frequency and voltage of the distribution network. The simulation results demonstrate the correctness and effectiveness of the proposed operation control method.

This paper summarizes the application scenarios of energy storage systems in power systems and the technical characteristics of different types of battery systems.Based on the typical structure of battery energy storage system connected to the grid, a simulation model of battery energy storage system connected to the grid was established, in which both the conventional charge and discharge PQ control strategy and the virtual synchronous control strategy providing transient stability support were considered.At the same time, according to the layout characteristics of distributed energy storage system, three different types of multi-point distributed energy storage system operation control modes are proposed, and combined with the typical system analysis example, to verify the effectiveness of the model and strategy.