Analysis of Multi-Resonant Current Control Structures and Tuning Methods

Integration-based controllers, such as the multi-resonant structures, are well adapted for multi-frequency current control applications. This paper presents a detailed design criterion of two different multi-resonant topologies, the first one based on a classical structure and a frequency response approach and the second one based on a state feedback structure and a pole placement approach. Digital implementation aspects (such as computation delays), inductance parametric errors and resonance phenomenon are taken into consideration during the tuning process. The comparison is carried out theoretically and experimentally based on an active filter application and considering various criteria, such as the computational load of the controllers and their performances in terms of transient response, steady state error and load unbalance response. Even if both control structures present correct steady-state performances, it has been shown that the classical structure is better adapted for active filtering applications, not only because it requires less computational operations but also due to its better transient and load unbalance performances