Gilbert Sybille

A power system simulation tool based on Simulink

This paper describes the Power System Blockset (PSB) from The MathWorks, Natick, MA, which is a new software package for the simulation of electric circuits, power systems, power electronic devices, and electric drives. The PSB is developed in the graphical Simulink environment of the general-purpose Matlab software. This blockset inherits a number of advantages from its development environment, namely, an open architecture, a powerful graphical user interface, and versatile analysis and graphics tools. The user can integrate control systems implemented with Simulink blocks directly into a diagram built with the PSB. Solution of differential equations is accomplished using the state-space approach with variable-step variable-order integration algorithms. A simulation example is presented, and the results are compared with those obtained with PSPICE.

Theory and applications of power system blockset, a MATLAB/Simulink-based simulation tool for power systems

This paper presents a unified framework for power system simulation using a Simulink environment. The modeling and simulation of power systems under Simulink are described and discussed. Application examples for power systems including power networks, power electronics and electric machines are presented and compared with two popular simulation packages (EMTP, PSpice).

Analysis and validation of a real-time AC drive simulator

This paper presents the analysis and validation of a real-time AC drive simulator. Real-time simulation has been used for over a decade in power systems engineering to test controllers thoroughly, efficiently, and safely. The development and testing of large DC drives could benefit from this type of simulation, but real-time power system simulators have modeling restrictions preventing stable and accurate simulation of isolated drives switching at high frequencies. These restrictions can be overcome by combining in a single model both the power converter and motor models. After discussing the salient issues related to the real-time simulation of DC drives, a prototype real-time simulator for drives is described. Its ability to accurately emulate the behavior of large drives is demonstrated through two case studies. A first case study demonstrates the feasibility of simulating a drive of typical complexity in real-time. The second case study demonstrates how the controller for a PWM VSI fed induction motor, switching at 4 kHz, is designed, implemented in a microcontroller and tested in real-time using a simulated inverter, motor and load. Comparisons against results obtained with another simulation tool, which uses extremely accurate variable-step integration algorithms, demonstrates the validity of our approach.

Hysteresis modeling in the MATLAB/power system blockset

This paper presents a static hysteresis model for the saturable transformer blocks in the Power System Blockset (PSB), a MATLAB/Simulink®-based simulation tool. This model will be available in version 3.0 of the PSB (also called SimPowerSystems) and offered as an alternative to the actual core saturation characteristic. The effect of hysteresis and eddy losses are of significance in the studies of: sub harmonic; residual flux effects on the transformer inrush currents; ferroresonance phenomena; harmonics generated by half-cycle saturation.The static model of hysteresis defines the relation between the flux Φ and the magnetization current (i.e. the current through the nonlinear inductance in the model) that is equal to the total excitation current measured in dc (when the eddy current losses are not present). It is useful under transient conditions and can represent minor loops.The principal points are: in transient conditions an oscillating current will produce minor asymmetrical loops; inside a minor loop the excitation curve depends only on the last two reversal points, and each curve tend to return to the reversal point previous to the last.A hysteresis design tool consisting of graphical user interface (GUI) allows precise adjustment to any major loop or saturation characteristic. An animation option of the GUI permits an open loop simulation so to visualize the operating point displacement within the major loop and the formation of the minor loops.Finally, an example case is described to illustrate remanent flux and inrush current at transformer energization.

Design and implementation of a versatile stepper motor model for simulink’s SimPowerSystems

This paper presents the design and implementation of a versatile model of stepper motors for use in Simulinkpsilas SimPowerSystems simulation engine. The model can represent different types of stepper motors: variable-reluctance, permanent-magnet and hybrid. The models are based on linearized equivalent circuits representing the operation of the motor. The implementation of the models of variable-reluctance and permanent-magnet or hybrid stepper motors in Simulink environment is presented. The operation of the developed models is verified and validated by test circuits. An open loop positioning system using a two-phase hybrid motor is described to illustrate the use of the developed model.

Open data IEEE test systems implemented in SimPowerSystems for education and research in power grid dynamics and control

This paper presents three IEEE standardized power system benchmarks developed in SimPowerSystems, a MATLAB/Simulink package. The simulation models can be used for baselining and testing new control techniques and protection algorithms for renewable and micro grids integration studies. Analytical examples as well as static, time domain, and frequency analysis are presented to support the correctness of the implementation. The models are available in MATLAB-Central file exchange for power system education and research worldwide.

An approach for real-time simulation of electric drives

This paper investigates simulation techniques which differ widely from those actually used in real-time simulation of large power systems. The objective is to simulate electric drives in real-time, in order to provide drive designers with a tool which would allow them to design and prototype the controller stage of high power drives without actually needing the cumbersome power source, converter and machine. The fundamental differences between the simulation of drives and large power systems are identified. This motivates investigation of a modeling technique based on the state variable approach (SVA). An integration algorithm is then proposed to solve the state space equations. Off-line results of a case study are presented, after which limitations and applicability of this method are presented and implementation issues on a multiprocessor computer are discussed.

MATLAB/Simulink and PSPice as modelling tools for power systems and power electronics

The Power System Blockset (PSB) simulation tool uses the MATLAB/Simulink environment to represent common components and devices found in electrical power networks. The PSB is well suited to the simulation of medium size power systems and power electronics using variable or fixed step algorithms from Simulink. The PSB libraries contain basic elements as well as many ready-built sub-systems. Control systems using Simulink blocks can be naturally integrated into the power system model. The computation capabilities of MATLAB/Simulink can be advantageously exploited in post-processing of the simulation results. SPICE (Simulation Program with Integrated Circuit Emphasis) can perform nonlinear DC, nonlinear transient, and linear AC analyses. In addition to the standard R,L and C elements, models for transmission lines and several semiconductor devices types are also available. In the study of power systems, PSpice is well suited for device-level modeling of small size systems: study of voltages and currents in power converters, snubber circuit design, study of transformer transients, etc. Also, PSpice performs well for system-level modeling of small size power systems (less than 30 states and 6 switches) using ideal switch models instead of detailed semiconductor models.

Power Flow and Stability Control Using an Integrated HV Bundle-Controlled Line-Impedance Modulator

This paper presents a flexible ac transmission system device under development for the management of power flow under steady-state and dynamic conditions, the bundle-controlled line-impedance modulator (LIM). In its simplest form, an LIM is made of switching modules connected in series with transmission-line segments whose bundles have subconductors insulated from each other. A module contains one switch in series with each subconductor of a bundle and the modules are anchored to dead-end towers in place of yoke plates. Together, with the measurement of sensors and controls, these modules can be used to change series impedances of transmission lines and implement functions, such as deicing, power-flow control, stability control, and line monitoring. In order to illustrate the LIM capabilities, two load-flow studies and one stability study are presented in this paper. Finally, the LIM performance is qualitatively compared to the thyristor-controlled series compensator technology.

Real-Time Simulation of PWM Power Converters in a Doubly-Fed Induction Generator Using Switching-Function-Based Models

This paper presents a study on the real-time simulation of power electronic PWM converters in wind generators using switching-function-based models instead of detailed switch models. Basic problems in real-time simulation of PWM converters connected to a power system are identified and possible solutions are discussed. Converter models using switching functions and an interpolation method are designed and evaluated. An application example consisting of a wind-turbine-driven doubly-fed induction generator is implemented in a real-time simulator. Simulation results are presented and the validity of the converter models is discussed