Modeling and controller synthesis for the cascaded H-bridge multilevel active power filter with ADALINE-based identifiers

This paper presents the averaged state-space modeling and controller synthesis methodology for the cascaded H-bridge multilevel active power filters (CHB-APFs). The accurate harmonic current compensation and dc-link stabilization among the individual H-bridge modules are crucial problems for the CHB-APF, which is the prerequisite for the global stability of the system. In this study, a novel voltage balancing algorithm is devised by splitting the dc-link control task into two parts, namely, the average voltage control and the voltage balancing control, where the sine and cosine functions of the phase angle of the fundamental grid voltage are used, respectively. To ensure accurate phase tracking, a novel phase-locked loop algorithm is proposed by using the adaptive linear neural network (ADALINE). Moreover, a separate ADALINE identifier is applied for reference current generation, and the proportional-resonant controller is used for current tracking. The simulation results obtained from the Alternative Transient Program (ATP/EMTP) are provided under dynamic reactive power compensation and active filtering scenarios. The experimental results from the prototype system are also presented, which verifies the effectiveness of the devised algorithms.