Model Predictive Current Control With Lyapunov Stability Constraints For Grid-Connected Inverter

The development of renewable energy is important to resolve the contradiction between economic development,social resource and ecological environment.The grid-connected inverter,which is the connection between renewable energy generation and grid,decides the energy efficiency and power quality.Model predictive control(MPC)becomes a concern because of its dynamic performance and multi-objective optimization by adding constraints.Therefore,the dynamic performance of grid-connected inverter can be improved by MPC.First of all,the topology,control strategy,filter and its stability analysis theory axe introduced.The mathematical model is established based on three-phase two-level inverter and the parameter selection of DC-link capacitance and AC side filter inductance is given.In addition,the parameter design method of the current controller is analyzed between the PI and MPC.The stable and transient performance will be compared and analyzed in the simulation of two proposed control strategies.The disadvantage of MPC is analyzed and an improved method of MPC is proposed.The delay time is compensated by increasing the number of times of prediction,and the future reference value in the delay compensation is predicted by introducing the Vector Angle Compensation Method(VACM).The satisfied transient performance of MPC can be obtained.Finally,the superiority of the improved strategy is verified by simulation.From the perspective of large signal stability,the Lyapunov stability constraint condition of grid-connected inverter is derived based on the Lyapunov and backstepping method,and the Lyapunov stability constraint is introduced in the improved MPC.Based on this,the on-line stability enhancement control of the grid-connected inverter is realized and the difficulty in selecting the weight coefficient of the multi-objective model predictive control is also avoided.Finally,the Rapid Control Prototype experimental platform of grid-connected inverter is built based on RT-BOX real-time emulator.The experimental results show that the improved model predictive control with Lyapunov stability constraints can effectively enhance the stability of grid-connected inverter.