Real-Time Digital Simulation of Power Electronic Apparatus Interfaced with Digital Controllers

Abstract

This paper presents a new approach for the real-time digital simulation of power electronic controllers in power systems. Digital controllers for power electronic systems present a problem when testing in real-time using a digital simulator due to the discrete nature of their outputs which are not necessarily in synchronism with the time step of the simulator. The proposed algorithm combines the variable step-size numerical integration method with linear interpolation for the synchronization of a real-time digital simulator and a digital controller. It is shown that lack of such synchronization leads to inaccurate simulation results, specifically with regard to the fundamental and harmonics of the voltage and current signals. Sampling theory is used to model the interaction between a digital simulator and a digital controller. A Pulse Width Modulated (PWM) Voltage Source Converter (VSC) based reactive power compensator system is used as an illustrative example for the simulation.

Flexible Numerical Integration for Efficient Representation of Switching in Real Time Electromagnetic Transients Simulation

“…2 The application of the backward-Euler method to discretize (1) yields: (6) Thus, the following associated discrete circuit model is obtained with the backward-Euler method:…”

“…T HE RAPID progress in computer hardware performance and the creation of both efficient and accurate simulation algorithms have contributed to the development of real time digital simulators [1]- [6]. In real time simulation for equipment testing, the simulation time advances at the speed of the real time so that results are output in synchronism with the real time clock.…”

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“…By using the full-digital simulator, the engineers can achieve a small size and flexible tuning simulation environment. Thus, the real-time simulation has become a famous technique [1][2][3][4] in designing a power electronics circuit. The merits and the drawbacks of a digital real-time simulator are summarized in Table 1.…”

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