An Angle-Oriented Limiting Method for Modulated Model Predictive Control to Implement a Grid Simulator

Abstract

Voltage emulator for power-hardware-in-the-loop test-bed needs fast dynamics, and model predictive controller can provide that. Power electronics devices such as inverter has relatively short computation time for control algorithm, reflecting finite control set model predictive control is introduced. However, finite control set model predictive control has important drawbacks. It has wide spread frequency spectrum and large ripple even in the steady state. This paper discusses a modulated model predictive control, which ensure fixed switching frequency using pulse width modulation. When large reference changes, the modulated model predictive control is expected to face constraints from voltage source inverters. The modulated model predictive control is regarded as quadratic programming problem, but geometric analysis is involved, it can be computed non-iterative manner for optimal control. Futhermore, the predictive model is modeled reflecting zero order hold behavior in stationary reference frame, and the cost function to improve transient response of modulated model predictive control is proposed. Simulation results demonstrating the proposed control algorithm are presented through step responses under different load conditions and various reference values.