Thyristor-controlled LC-coupling hybrid active power filter (TCLC-HAPF) offers low DC-link voltage and a wide reactive power compensation range, making it a promising solution for power quality compensation in medium-voltage power systems. Recently, conventional finite-set model predictive control (FS-MPC) was proposed to control the TCLC-HAPF. It requires state prediction and enumeration/rolling optimization for obtaining optimal inverter voltage vector, which is computationally intensive. This paper proposes a finite-set simplified model predictive control (FS-SMPC) that eliminates the prediction and enumeration processes, therefore reducing computational burden. Simulation results are provided to verify the feasibility and effectiveness of the proposed FS-SMPC.

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).

This paper presents a passive control method utilizing an auxiliary protection circuit for LCC-S compensated converters. The proposed method effectively addresses the challenges of over-load and over-aligned conditions, which can cause excessive inverter output current and higher-than-required system output voltage. By incorporating the auxiliary protection circuit, complex compensated circuits and wireless communication are eliminated, providing a simple and reliable solution. Experimental validation was performed in a 48 V wireless charging prototype to demonstrate the efficacy of the protection strategy in promptly safeguarding the primary circuit against device damage.

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.

48th Conference of the Industrial Electronics Society-IECON-Annual -- OCT 17-20, 2022 -- Brussels, BELGIUM

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 a promising current quality compensator in the medium-voltage-level power system, which is characterized by a wide operational range and low DC-link voltage. Based on the simplified discrete model, this paper proposes a deadbeat current control (DBCC) scheme for the TCLC-HAPF. The proposed controller can lead TCLC-HAPF to be operating at a fixed switching frequency and track the reference compensating current accurately with a fast transient response. Simulation studies under both balanced and unbalanced load conditions are conducted to verify the proposal.

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.

LC-coupling hybrid active power filter (LC-HAPF) is one of the most cost-effective solution for power quality problem in distribution networks, in which its performance is mainly affected by the current controller. Among the state-of-the-art current controllers for the LC-HAPF, the second-order sliding mode controller (SOSMC) performs a superior dynamic and steady-state performance simultaneously. However, the existing SOSMC design method did not consider the upper bound of the control parameters, which may lead to saturation effect and control performance degradation. In this paper, a SOSMC design method based on describing function (DF) is proposed, which contributes the upper bound design constraint. The DF control block diagram for the LC-HAPF enables frequency domain analysis of SOSMC. Moreover, the analytical upper bounds of the SOSMC's control parameters are provided to avoid the saturation effect. Finally, the advantages of the proposed SOSMC design based on DF are verified by simulation results compared with the existing SOSMC design method under low DC-link voltage condition.

With the characteristics of a low dc-link operating voltage of the active inverter part and thyristor controlled passive part, the hybrid-coupling grid-connected inverter (HGCI) can reduce the system and operational costs as well as extend the operational range compared with the conventional inductive-coupling grid-connected inverter (IGCI) and capacitive-coupling grid-connected inverter (CGCI) for the renewable energy generation. In this paper, a control strategy by using proportional-integral (PI) controller of the HGCI for active power injection and unbalanced non-active power compensation will be proposed and presented, which can reduce the switching current ripple and obtain better active and non-active power compensation compared with the conventional hysteresis current controller. Finally, simulation and experimental results are provided to verify the performance of the designed PI controller for the HGCI under unbalanced loads operation.