Research on Deadbeat Control of Three-level Active Power Filter

Deadbeat control is proposed for a shunt active power filter(APF) based on three-level inverter to reduce line current harmonics. Firstly, the working principles of harmonics detection and the mathematical models of the 3-phase 3-wire three-level trileg APF were introduced in details. Based on the above models of state equations, the work found that the predictive harmonic current value of one sampling period ahead is the most important step in deadbeat control strategy. Moreover, an effective method of harmonic current prediction was presented for nonlinear loads both in steady and dynamic state operation. The experimental results show that the compensating ability of this APF is high in accuracy and responsiveness.