In this paper, a model predictive robust control (MPRC) is proposed for a three-phase capacitive-coupling grid-connect inverter (CGCI) to improve the power quality compensation performance under deviating system parameters. A detail stability study and parameter design of the proposed MPRC is provided, while the robustness and power quality compensation performance of the proposed MPRC are verified by the simulation in comparison to the conventional model predictive control (MPC).

In this paper, a multi-quasi-proportional-resonant control (MQPRC) for a three-phase capacitive-coupling grid-connect inverter (CGCI) with accurate active power injection technique is proposed to mitigate the current harmonics and improve the active power injection accuracy. Then, a detail parameter design of the proposed MQPRC is provided. And the proposed accurate active power injection is verified by the simulation. Subsequently, to verify the effectiveness of the proposed MQPRC, the simulation results are presented in comparison to the quasi-proportional-resonant control (QPRC).

In this paper, an improved model predictive control (MPC) is proposed for a single-phase LC-coupling hybrid active power filter (LC-HAPF), which ensures the low steady-state error and fast transient response. Generally, the intrinsic discretized and predictive error of the traditional MPC for the LC-HAPF enlarges the steady-state error. To relax this problem, a signal correction technique is proposed, and therefore reduce the steady-state error. Then, the parameter design of the proposed improved MPC for the LC-HAPF is given based on the stability analysis. Finally, simulated results are provided to verify the effectiveness of the improved MPC compared with the traditional MPC.

Compared with traditional active power filter (APF), the dc-link voltage of LC-coupling hybrid active power filter (LC-HAPF) is lower, thus reducing the system cost and power loss. In order to improve the compensation performance of the LC-HAPF, many current controllers have been proposed in recent decade, which are hysteresis current control (HCC), quasi-proportional-resonant control (QPRC), deadbeat current control (DBCC), second-order sliding-mode control (SOSMC), vector proportional-integral current control (VPIC) and improved model predictive control (IMPC). In this paper, the model of these six controllers will be first reviewed and introduced. After that, their corresponding parameters design methodology are given. Finally, simulation results will be given to compare their compensation performance and summarize their characteristics.

Thyristor-controlled LC-coupling hybrid active power filter (TCLC-HAPF) is characterized with low DC-link voltage and wide operational range, which was recently developed for power quality conditioning in the medium-voltage-level system. This paper proposes a fuzzy logic based adaptive source current total harmonic distortion (THD) controller for the TCLC-HAPF. The proposed controller can adaptively change the hysteresis band (HB) according to the reference THD value, thereby possibly reduce the switching loss and keep the source current THD at an acceptable reference level. Simulation is conducted for verifying the proposed controller, in comparison with the fixed HB controller.