Real-time simulation and animation for dynamic control systems

Based on the design characteristics of the stability control system, the control strategies of each station in the system are abstracted and integrated, and classified into standardized logic and customized logic. Based on the real-time digital simulation system platform, a three-layer architecture of the real-time simulation platform for the large-scale stability control system is designed. The standardized simulator based on FPGA/DSP and the customized simulator using device virtualization technology are designed in detail. The design scheme of the real-time accurate simulation platform for large-scale stability control system is proposed. From the perspective of hardware requirements, simulation accuracy, and platform adaptability, the differences between the simulation platform and the existing real-time digital simulation test platform are compared and analyzed.

Advanced high quality radiation therapy techniques such as IMRT require an accurate delivery of precisely modulated fluence patterns to the target volume. Intrafractional motion, however, may considerably deteriorate the accuracy of the dose delivery. To compensate for these errors, a dynamic real-time capable MLC control system was designed and implemented which compensates during the delivery for the motion and deformation of the target volume. Specialized algorithms were developed which constantly optimize the MLC aperture based on online provided target information allowing the sparing of adjacent organs-at-risk from additional dose. These algorithms were implemented in a dynamic target tracking control system for the Siemens 160 MLCTM. Experiments using different phantom setups were performed to assess and quantify the quality of the tracking technique. The results showed that 2-dimensional target motion can be compensated for with the new control system. For a clinical IMRT dose distribution, the congruence within 2 % / 2 mm with a static reference delivery was increased from 18.75% to 76.79 %. Similar improvements were achieved for the delivery of a complete IMRT treatment fraction to a moving lung phantom. However, the quality of the tracking system is limited by the system’s latency times. The experiments proved that the tracking concept, the new algorithms and the dynamic control system allow to effectively compensate for target motion in real-time. It therefore can increase the accuracy and the quality of the treatment delivery.KeywordsAdaptive RadiotherapyTumor TrackingDynamic Multileaf CollimatorMotion Management

This paper presents the implementation and experimental details of a real-time digital simulator designed for representing a Distribution Static Compensator (D-STATCOM) interfaced with a digital controller. Real-time simulation using conventional fixed time-step integration algorithms can lead to erroneous results due to the lack of synchronism between the simulator time-step and the discrete switching signals coming from the digital controller. The real-time simulation algorithm implemented in this paper overcomes the drawbacks of a fixed time-step algorithm. The real-time algorithm relies on precise registration of timing of the incoming discrete firing pulses and a subsequent correction procedure to calculate the system state. This approach has been implemented on a hybrid digital processing platform comprising of a Digital Signal Processor (DSP) and a Field Programmable Gate Array (FPGA). The platform represents both the power electronic system and the digital control system. Experimental results, for a 5 kV A D-STATCOM system, in verification of the real-time simulator results are also provided.

The proportion of renewable energy resources in modern power grids is expected to rise and displace fossil-based generating units, resulting in shallower inertia levels. Power grids lacking sufficient inertia are susceptible to instability issues. To alleviate such issues, virtual inertia synthesis has been proposed to enhance the dynamic performance of weak grids. In that regard, this paper investigates the impact of inertia reduction on the stability of the islanded microgrid using model-based layouts and real-time simulation. Elevated small-signal models are used to examine the evolution of the dynamics of the microgrid components. A virtual inertia control is also integrated to regulate the frequency and minimize the Rate of Change of Frequency (ROCOF) in an islanded microgrid. The present study is validated on a realistic benchmark constructed in the Real-Time Digital Simulator (RTDS). The model-based layouts are also verified using non-real-time simulation in MATLAB. The conducted simulation shows the ability of the proposed control design to regulate the frequency and minimize the ROCOF during system disturbances in both simulation environments.

This paper describes a method for implementing a gradient-based nonlinear optimization technique for optimal tuning of nonlinear power system controllers such as a flexible ac transmission system (FACTS) via a combination of hardware and software in the real-time digital simulator (RTDS). The RTDS offers fundamental advantages over other commercial software tools because it is a fully digital power system simulator that operates in real-time. Therefore, nonlinear optimal parameters can be effectively determined under similar environments to actual physical systems by this real-time implementation. In this paper, Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimization algorithm, which has a quadratic convergence property, is implemented in order to design the nonlinear controllers in power systems. Its effectiveness is demonstrated with two design examples intended to improve low-frequency oscillation damping in power systems. After illustrating an example to optimize nonlinear parameters of the power system stabilizer (PSS), the paper introduces optimal design of an external controller (EC) for the series capacitive reactance compensator (SCRC), which is one of the FACTS devices, in real-time simulation.

An airbreathing hypersonic vehicle(AHV) generally adopts a scramjet engine as its propulsion, which needs strict conditions of flight dynamic pressure. A new dynamic pressure control system is presented, in which the AHV autopilot directly uses dynamic pressure to track the dynamic pressure command. Firstly, the dynamic pressure model of the AHV is established and the state equations of dynamic pressure control are given. Then, the dynamic pressure control system is implemented using the LQR optimal control theory. The dynamic pressure error is augmented in order to add an integral control to track the dynamic pressure with zero steady error. The structure of the dynamic pressure control system is also obtained. The simulation results show that the dynamic pressure control system has a good performance for guaranteeing the dynamic pressure of the scramjet engine with the disturbance of drag and thrust considered.

A methodology for digital real time simulation of dynamic systems using modern DSPs

Nowadays in high-power industrial processes, multipulse cycloconverters are the most commonly used converter for high power mill drives. This paper propose an analysis of the interharmonics currents behavior under an unbalanced load, injected by a Cycloconverters (CCVs) with 12- pulse configuration and multi-winding transformers. Three-phase transformers with two secondary windings with star and delta connection and a three-phase RL load with a decoupled direct current load control are used to simulate the system. The prototype of the power system is embedded on a real-time simulator. Performance is tested on a digital real-time power system simulation (RTDS) and results are analyzed with external equipment and compared with theory.

The paper presents the analysis on stability of digital control system for unmanned vehicle with numerical analysis. The objective of this study is mainly emphasized on the fulfillment of the advanced control techniques according to the fundamental concepts of digital control system approaches for unmanned aerial vehicle system design. The targeted unmanned aerial vehicle system was designed based on the simple construction under the idea of fixed wing flight system approaches. The stability analyses on unmanned aerial vehicle are vital role to enhance the real world applications. The background concepts on digital control system for stability analysis on dynamic control system like unmanned aerial vehicle system. The appropriate controller design for dynamic control system of unmanned aerial vehicle is vital role to analyze the accurate stability condition for reality. The implementation of numerical analysis on compensator design has been developed by using MATLAB. The physical parameters in these analyses are based on the experimental outcomes from the recent research works in dynamical system implementations. The mathematical approaches are very helpful for numerical analysis on compensator design for the unmanned aerial vehicles schemes. The simulation results confirm that the high performance stability test on unmanned aerial vehicle system has been met with the theoretical works.

With the introduction of high-speed relaying systems, the need for extensive testing of these systems for different fault and abnormal conditions has become more important, to ensure the security and dependability of the electric power systems. Testing of relays can be summarized into three groups: steady state, dynamic and transient. While the first two types are performed during bench testing, they are not adequate for performance evaluation of subcycle modern relays. Transient testing is performed for verification of relay performance under transient conditions of power system to address such requirement. ABB has been using real-time simulations of power systems, for relay performance evaluation, for around seventy years in the US. This paper discusses the methodology employed for real-time simulations of power systems with different technology, with specific focus on the state-of-the-art real-time digital simulator from EDF. Specific case study related to the performance evaluation of a line relay system is discussed in this paper.

Superconducting Generator (SCG) has many advantages such as small size, high generation efficiency, low impedance, and so on. An improved power system with many potential good properties may be obtained by introduction of SCG. In order to study the behaviors of SCG in power systems, a digital type SCG model for an existing analog type real-time power system simulator is developed in this work, which is suitable for real-time simulations when the generator constants and control systems are changed frequently. By use of the above-mentioned equipments, real-time simulation in cases of SCG with different generator constants and in case of SCG in multi-machine power system has been conducted. The real-time simulation results verify the effects of SCG on power system stability enhancement and show the influence of generator constants on its stability-improving effects.

The need for real-time simulation stems from the fact that in many practical situations it is desirable to analyze the dynamic behavior of a large power system with advanced equipment that has complex and high-speed performance. Analog simulators are effective, however they impose serious limitations on the size of the system that is being modeled. The authors have studied and developed a real-time digital simulator using a hypercube computer, and realized a real-time performance available for the analysis of large power systems. Now as the second step of their study, they developed a digital/analog conversion interface for testing actual power instruments. The interface exchanges the variables of fundamental frequency domain in the real-time digital simulator, and the variables of exact time domain in the analog equipment connected to the simulator. In this paper, the authors describe the detail of their developed digital/analog conversion interface of the real-time digital simulator for testing advanced power instruments. Its conversion algorithm, the system configuration of the simulator with the interface, and experimental results are also presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The Smart Grid Operation Centre (SGOC) is established on 1st April, 2021, as part of the purpose-built facilities of the Haking Wong Campus of the Hong Kong Institute of Vocational Education (IVE), a Vocational Training Council (VTC) member institution. With the generous contributions and steadfast support from CLP Power Hong Kong Limited (CLP Power), SGOC is served as simulation and training facility available to support all Smart Grid development in Hong Kong. The SGOC has installed the Real-Time Digital Simulator (RTDS) and Smart grid-related equipment, including the Distributed Energy Resources (DERs), protection relay, and smart meter that can be looped into the simulator, for its capability and interoperability on real-time studies, including modeling and resolving the potential issues in realtime before they may impact the delivery or operation of the project or the smart grid network. Facing the up-coming challenges with penetration of renewable energy, digitalization, and increasing of electric vehicles, the SGOC provides a feasible range of smart grid related services in respect of real-time studies on the operation of smart grid system, operator training, and operational support that enable derisk deployment and operation of the related smart grid parties, and more practical and tailored training which increases familiarity and confidence of operators. This paper describes the practicalities of specifying, testing, installation and interfacing the platform, with a realtime simulator, at the SGOC, for future operational training and support use, including some uses on faults during operation, diagnosing alarms, scheme updates/upgrades and network interactions and range of smart grid focused training courses will be available and content enhancement into course delivery. Through these wide-ranging installations and systems, trainers will learn to apply the latest industry technologies. This will enrich their knowledge of smart grids and relevant new technologies, thereby helping to promote smart, clean energy development. This paper is also included the Power Hardware- In-the-Loop (PHIL) platform and a case study introduction for the frequency capability for microgrid and Battery Energy Storage System (BESS) response.

This paper presents a study in the field of electric motor drive testing. One example of propulsion drive load dynamic control system is presented. Mathematical model of the propulsion motor drive of Tesla Roadster is presented. Suggested dynamic load control system is verified using a MATLAB/Simulink computer model and a test bench. The developed methodology can be recommended to adjust the electrical drives for different kinds of testing equipment, including the synchronous, reluctance, induction, and direct current machines.

In this paper, a novel Trust Region based Sequential Linear Programming (TRSLP) method is proposed for unscheduled intentional islanding in microgrid. In unscheduled islanding, the solution must be obtained with minimum time and minimum load curtailment by maintaining all the system parameter constraints intact. First, the unscheduled intentional islanding is formulated as a nonlinear constrained optimization problem. Then, the TRSLP based optimization method is employed to obtain the final switching sequence of the network so that intentional islanding can be done in optimal manner. The objective function of the optimization problem is to minimize the amount of load curtailment. To validate the proposed technique, a 7-bus microgrid test system is simulated in Real-Time Digital Simulator (RTDS) and corresponding system parameters are further used in the TRSLP optimization technique to get the optimal islanding area.