Improve Dynamic Response of A New Type of Predictive Controller Based on Erea Equivalent

Abstract

Predictive control has high dynamic response characteristics and can effectively improve the performance of inverters. Proportional-Proportional-Delay (PPD) is a new type of predictive controller. Compared with the existing predictive controllers, it has the advantages of less computation and higher bandwidth, and it can theoretically realize deadbeat control. However, in the actual digital system, the excitation voltage output by the PPD controller is limited by the limiter module in some working conditions, which reduces the response speed of system. This paper first analyzes the mechanism that the limiter module affects the dynamic characteristics of PPD controller, and deduces the most seriously affected working conditions. Then, based on the area equivalent principle of excitation voltage, a strategy for improving the dynamic characteristics of PPD controller in the actual system is proposed. The core idea of this strategy is to allocate the limited excitation voltage to the modulated wave of the subsequent switching cycle equivalently. And before the grid current is equal to the reference current, the modulated wave is controlled to run at the limit maximum capacity of the limiter module. Finally, an experimental prototype was built to verify the proposed strategy.