To design a high reliability multilevel grid-connected inverter, a high performance simulation methodology based on Saber is proposed. The simulation methodology with optimized simulation speed can simulate the factors that have significant impacts on the stability and performance of the control system, such as digital delay, dead band, and the quantization error. The control algorithm in the simulation methodology is implemented using the C language, which facilitates the future porting to an actual system since most actual digital controllers are programmed in the C language. The modeling of the control system is focused mainly on diode-clamped three-level grid-connected inverters, and simulations for other topologies can be easily built based on this simulation. An example of designing a proportional-resonant (PR) controller with the aid of the simulation is introduced. The integer scaling effect in fixed-point digital signal processors (DSPs) on the control system is demonstrated and the performance of the controller is validated through experiments.

关键词： Multilevel grid-connected inverter,  Simulation methodology,  Proportional-resonant (PR) controller