Study on the development of real-time digital simulation based on Matlab

In order to reduce the development costs and shorten the development period of power electronic experiments, a real-time digital simulation test system for rectifying devices is presented in this paper. This system combines the traditional simulation software SIMULINK with high-performance industrial personal computer (IPC). SIMULINK is used to create system model and the interface module. The RTW toolbox provided by SIMULINK is used to convert the model to C code, which is then uploaded to the IPC. When the C code runs, the test signals required by the control board are output through the I/O or Ethernet port. What's more, the simulation model can be modified in real time according to the control signal fed back by the control board, and can also be used to carry on the hardware-in-loop simulation test. In this paper, many problems were solved or mitigated, such as numerical oscillation in the off-line simulation, the cumbersome process of the model converting to C code, and the real-time performance of the task scheduling strategy of the computing unit. At last, some experiments were done to show that the system has strong real-time performance and can be used in the experiment of rectifier.

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.

Modelling, simulation and experimental verification for renewable agents connected to a distorted utility grid using a Real-Time Digital Simulation Platform

This paper presents a new simulator used to distribute and execute real-time simulations: the RT-LAB, developed by opal-RT technologies (Montreal, Canada). One of its essential characteristics is the perfect integration with MATLAB/Simulink. The RT-LAB allows the conversion of Simulink models in real time via real-time workshop (RTW) and their execution on one or more processors. In this context, the paper focuses on the RT-LAB real-time simulation as a complement to the MATLAB/Simulink environment, which has been used to perform the simulation of the Flywheel energy storage system (FESS -variable speed wind generation (VSWG) assembly. The purpose of employing a fairly new real-time platform (RT-LAB OP -5600) is to reduce the test and prototype time. This application will be executed on each element of our model that was previously developed under MATLAB/Simulink. The real-time simulation results are observed in the workstation.

This paper studies two cutting edge technologies applied to the power system: FACTS devices and real time (RT) simulation tools. On the one hand, the complexity of the power system and its components, makes power system simulators very useful and even necessary. Amongst all the existing simulators, real time digital simulators permit the test of power system components in conditions that are quite close to reality. On the other hand power electronic devices such as FACTS, are becoming more and more frequent on the power system, and it is necessary to evaluate their impact on the performance of the system. For all these reasons it is very important to develop FACTS models which can be suitable for real time simulation in order to test their interaction with other power system components. This paper presents the generalized average model of two FACTS devices the static VAr compensator (SVC) and the static VAr generator, which have been then introduced in ARENE for the realization of real time simulations.

In a competitive world, using real-time simulation rather than off-line simulation provides significant advantage for imitating system dynamics in a real world. Real-time simulation could minimize decision risks for real implementation, shorten design cycle, enhance reliability of research results, and, last but not least, save research and development cost. Moreover, real-time simulation could be also implemented to include real hardware into the loop while is kept as flexible as an off-line numerical simulation. In this paper, a real time simulation mechanism is presented for studying switch reluctance motor (SRM) drive control powered by a fuel cell. The fuel cell stack model is simulated by a software package developed by Emmeskay, Inc., which can be operated in real time. The whole real time simulation is conducted on a two-node platform hosted by RT-Lab, a software product of Opal-RT Technologies, Inc. and engineered by fixed-step real time operating system. In particular, as an illustrating example, an SRM drive control model is first built and then connected with fuel cell stack model. The whole system model is then compiled and operated in real-time on the two-node platform. The real-time simulation result is validated by its off-line simulation counterpart. It is pointed out that this real-time simulation set-up could be easily converted into a hardware-in-the-loop (HIL) simulation carrying real hardware such as microcontroller, real motor, etc., when deemed as necessary. The simulation methodology presented in this paper also indicates a potential low cost approach to support experimentally real-time research and development activities for fuel cell related systems. Considering the high cost to build a real fuel cell system, the set-up described in this paper is extremely meaningful for research and development communities.

This paper describes the application of a controlled switching device to energize a 500 kV/230 kV/46 kV, 1200 MVA autotransformer in Manitoba. The development of a detailed electromagnetic-transient (EMT) simulation model of the transformer formed the basis of the work described. The transformer model includes an accurate representation of hysteresis and remanance, which was validated using recorded waveforms and manufacturer data. This paper discusses a feasibility study conducted using this transformer model to evaluate the suitability of controlled switching to energize this transformer. A series of real-time hardware in the loop tests was conducted using a real-time simulator as part of precommissioning tests. The real-time simulation (RTS) tests and phase 1 of commissioning tests conducted in October 2014 showed that the controlled switching device would produce inaccurate residual flux estimates when it integrates the secondary voltage waveforms of a capacitive voltage transformer. Based on these RTS test results and EMT simulations, the installation of a wound potential transformer (PT) was recommended. This paper also discusses simulation studies conducted to manually program the controller until the PT was commissioned. During phase 2 of testing conducted in October 2015, a wound PT was commissioned and the controller was tested. The recorded waveforms showed good agreement with simulation results. The controller has accurately predicted residual flux and minimized inrush currents during transformer switching events.

The Real-Time Simulator tools have high computing technologies, improved performance. They are widely used for design and improvement of electrical systems. The advancement of the software tools like MATLAB/SIMULINK with its Real-Time Workshop (RTW) and Real-Time Windows Target (RTWT), real-time simulators are used extensively in many engineering fields, such as industry, education, and research institutions. OPAL-RT-OP4510 is a Real-Time Simulator which is used in both industry and academia. In this paper, the real-time simulation of IEEE-5-Bus network is carried out by means of OPAL-RT-OP4510 with CRO and other hardware. The performance of the network is observed with the introduction of fault at various locations. The waveforms of voltage, current, active and reactive power are observed in the MATLAB simulation environment and on the CRO. Also, Load Flow Analysis (LFA) of IEEE-5-Bus network is computed using MATLAB/Simulink power-gui load flow tool.

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.

Real-time digital simulation and graphic animation limited band-width dynamic control systems can significantly enhance the interpretation and understanding of system responses. This paper outlines an efficient techniques for generating the graphics and the timing in real-time simulation and animation of the dynamic control systems using a high-speed high- performance PC-AT microcomputer. For illustration, the simulation and animation results for the adaptive computer controlled suspension of a combat vehicle and for the gun-turret stabilization and tracking control system for combat vehicle are presented.

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.

Gain-margin based discrete-continuous method for the stability analysis of real-time hybrid simulation systems

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.

In order to analyze the DC integrated power systems containing a large number of switches accurately and quantitatively, this paper constructs a real-time simulation hardware-in-the-loop test platform. The platform integrates three key technologies, the first one is the real-time simulation method of large-scale power systems. This method is composed of modeling method of crucial equipment, network partitioning method, and electrical decoupling method. The second one is the construction of asynchronous communication interface. This platform realizes the function of uploading the system data to the database by UDP protocol and sending the control instructions to the system model by TCP protocol. The last one is the joint debugging of physical equipment and real-time simulator. Taking the integrated power system (IPS) as an example, the power system model is simulated by the real-time simulator, the network and energy management system are actual physical equipment, constructing the real-time simulation hardware-in-the-loop experimental platform. The real-time simulation performance and dynamic calculation results of the system verify the effectiveness of the real-time simulation method of large-scale power systems and the superiority of the platform.

Ultrasound imaging is used within numerous medical disciplines. Extensive and repeated training is needed for efficient use of the technology. Simulator training has been proposed as a complement to other training methods. Advantages of simulator training include access to a large number of normal and rare cases without the need for suitable volunteers and available ultrasound equipment. The imaging of soft tissue can be simulated by considering the interaction between the tissue and the ultrasound field. The objective of this study is to include these effects in real-time simulators. One previous approach has been to simulate a three-dimensional (3D) ultrasound volume off line, and then cross-section the volume in real time. This approach, however, does not take into account the anisotropic resolution of ultrasound imaging. If we assume that the average acoustical properties of tissues are slowly varying and that the speckle pattern is independent of the tissue, we show that ultrasound images can be simulated by multiplying a pre-simulated speckle image by an any-plane cross section of a 3D representation of an anatomy. Thus anisotropic resolution can be simulated in real time. The simulated images were compared to true ultrasound images of soft tissue. Since the speckle was simulated independently of the tissue, the most realistic results were obtained for still images, but the method was also satisfactory for moving images when speckle tracking between views was not important. The method is well applicable to ultrasound training simulators on low cost platforms.