PLL-less control for hybrid active impedance

Abstract

This work describes a PLL-Less control algorithm for the hybrid topology composed by a capacitor bank in series with an active impedance. This topology, named Smart Impedance, can be used in many applications. Hybrid Active Power Filter is one of these applications, where selective or simultaneous compensation of multiple harmonic components is possible. The control strategy uses the Proportional Resonant Compensators technique to achieve the desired behavior. The proposed algorithm totally eliminates the need for voltage synchronization as the resonant controller keeps track of the system current without the call for a PLL. The control algorithm is performed directly in the abc frame and practical results are presented to demonstrate the control performance and dynamics.

Research on Improved Control Strategy for STATCOM Based on Virtual Matrix Method

“…In [15], a software PLL is designed to replace the traditional PLL, but the error caused by the phase change of the grid voltage is not considered in this paper. In [16], the concept of "intelligent impedance" is introduced, and the function of the PLL is replaced by the intelligent impedance and proportional resonant controller. However, this method brings higher requirements for the design of parameters, which is not easy to achieve.…”