For the quasi-Z-source inverter (qZSI), capacitor voltage stability control, high performance of the inductor current reference tracking and fast response of the active/reactive power are key issues. Thus, a decoupled active/reactive power model predictive control (MPC) of the qZSI for distributed generations (DGs) is proposed to fulfill these requirements without additional control loops. Firstly, the digital observer is constructed to remove the utilization of the front voltage sensor and reduce the number of hardware equipment. Moreover, based on the advance determination of the system operation mode and the simplified cost function, the calculation complexity of the proposed MPC algorithm is simplified. Further, the proposed improved MPC method with the digital observer is proved to achieve the high accuracy and the zero prediction error, of which stability is demonstrated through Lyapunov stability criteria. Eventually, the proposed controller is compared with conventional MPC and PI controller in detail and its effectiveness is verified by both simulation and experimental results from a grid-connected qZSI.
For the quasi-Z-source inverter (qZSI), capacitor voltage stability control, high performance of the inductor current reference tracking and fast response of the active/reactive power are key issues. Thus, a decoupled active/reactive power model predictive control (MPC) of the qZSI for distributed generations (DGs) is proposed to fulfill these requirements without additional control loops. Firstly, the digital observer is constructed to remove the utilization of the front voltage sensor and reduce the number of hardware equipment. Moreover, based on the advance determination of the system operation mode and the simplified cost function, the calculation complexity of the proposed MPC algorithm is simplified. Further, the proposed improved MPC method with the digital observer is proved to achieve the high accuracy and the zero prediction error, of which stability is demonstrated through Lyapunov stability criteria. Eventually, the proposed controller is compared with conventional MPC and PI controller in detail and its effectiveness is verified by both simulation and experimental results from a grid-connected qZSI.