Passivity-Based Design for High-Order Harmonic Voltage Emulation of Grid Emulators

The high-order (i.e., 50th~ 100th) harmonic voltage emulation is increasingly required for future grid emulators. To mitigate adverse control interactions between grid emulator and converter under test, this paper proposes a passivity-based design method for the harmonic resonant controllers of grid emulators. This method selects the phase compensation angles of resonant controllers based on the theory of constrained piecewise linear fitting. Compared to conventional passivity-based design, the proposed method avoids complicated mathematical derivations and achieves precise harmonic voltage control with the passive harmonic impedance till the critical frequency of voltage control loop. The effectiveness of the proposed method is validated by experimental results.