High precision harmonic controller combined with repetitive and modulated model predictive controllers.

This paper proposes a high precision harmonic controller combined with repetitive and modulated model predictive controllers for standalone inverter applications. The proposed method is configured as a dual loop controller that includes an outer voltage controller with a plug-in repetitive controller (RC) and an inner current controller with a modulated model predictive controller (MMPC). The RC in the outer control loop effectively synthesizes the harmonic current reference when connecting a nonlinear load with a periodic harmonic current. Then, the MMPC-based current controller, with its ultra-wide bandwidth, regulates the harmonic current without additional harmonic current controllers. Thus, the abilities to precisely control the harmonic current and improve the output voltage quality are achieved. To combine the MMPC and the repetitive controller, an equivalent transfer function is derived from the ac sweep result of the MMPC. The stability of the RC is analyzed by applying the equivalent transfer function to the closed-loop voltage control model. To validate the performance of the proposed control method, a 3 kVA single phase 3-level T-type inverter prototype is built and tested. The harmonic compensation and dynamic performance of the proposed method are verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]