PLL-less control for hybrid active impedance

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.