Projection value-based smooth adaptive control strategy of single-phase DC-AC converters

State-space modeling is often used to design power converters so that the performance of the closed-loop control system can meet design requirements. However, single-phase DC-AC converters based on constant state feedback control have some issues, including long response times and unpredictable robustness. To solve these problems, a novel control strategy based on state feedback control (SFC), called the smooth projection adaptive strategy (SPAS), is developed by adaptively changing the state feedback coefficient according to the projection value of the system. First, a state space model of the DC-AC converter with the adaptive state feedback control law is established. Then based on the SPAS and considering parameters perturbation, two control laws named current-mode control (CMC) and voltage-mode control (VMC) are proposed, and their robustness are further discussed. Furthermore, the design method of the proposed control system in the digital control framework is presented. Finally, experiments on a 400 W prototype, and comparative analyses among the proposed control laws and the conventional PI control method are carried out. The results show that the proposed CMC has apparent superiority in terms of both static and dynamic performance.