Control Method for Single-Phase Active Filter Using Universal Smart Power Module (USPM)

Herein, we propose a control method for a single-phase active filter composed of a universal smart power module (USPM). The USPM is a modularization technology concept that comprises various power conversion systems. Depending on the application, the USPM is a full-bridge inverter with a wideband controller and filter, and the power converter is constructed using several USPMs. In this study, the target system was an active filter composed of modules connected in series or parallel to accommodate arbitrary voltage and current capacitances. The proposed method solves the communication delays between the master and slave controllers owing to the distributed control in wireless communications and the interference problem caused by multiple USPM connections. The experimental results of the steady-state response showed that despite the communication delays, the total harmonic distortion (THD) of the input current was improved by up to 63.0%, and the power factor was 0.997. Moreover, load fluctuation experiments confirmed that the system transitioned to a steady -state and operated stably by updating the command value of the slave controller for the first time after the load fluctuation. The harmonic current elimination can be realized as an active filter, and the effectiveness of the proposed method was confirmed.