The variation of line impedance has always been a great concern for grid operators and industrial users. The problem is that the reliability and quality of the supplied power are influenced by this variation. Indeed, several standards and grid requirements fix strict rules and rigorous standards when connecting or disconnecting from the public grid. In this context, this chapter proposes a full study of a line impedance emulator, which includes the power design and the control. The line impedance emulator is useful for small scale laboratories that develop distributed energy generation. Developed line impedance emulator is based on a three-phase power converter. For these converters, different controls are applied, including proportional integral and resonant controllers. For the generation of voltage reference values that correspond to expected line impedance, two algorithms are studied, namely, trigonometric functions-based algorithm and voltage drop-based algorithm. The theoretical study is supported by simulation and experimental results.
Part of the book: Numerical Modeling and Computer Simulation
In this chapter, a photovoltaic system integrated into the building is investigated. The studied structure includes also a battery energy storage system. The overall system is connected to a four-wire AC bus, with the possibility to supply single-phase and three-phase loads. Each equipment is interfaced with a dedicated power converter. This chapter examines the technical operation of all structure components and gives a detailed mathematical study of the DC/AC power converter control in case of two modes, namely, grid connected mode and standalone mode. The investigated control is based on resonant controller. The resonant controller parameters tuning, which is based on the generalized stability margin criterion, is detailed in this chapter. To prove the performance of the proposed control algorithm, several simulation tests developed under PSIM software were performed and then validated by experimental results.
Part of the book: Numerical Modeling and Computer Simulation