Performance improvement of repetitive controlled PWM inverters: A phase-lead compensation solution

摘要

The compensation of the phase lag plays an important role in the improvement of convergence rate, tracking accuracy, and robustness of repetitive controller. However, it is often difficult to compensate the system phase lag exactly due to variation of the load and unknown disturbances. An alternative way is to provide a simple but effective phase compensation to compensate the phase lag in a frequency band that contains the major tracking error components. With this motivation, a repetitive control scheme with a linear phase-lead compensator is proposed and applied to the control of constant-voltage constant-frequency pulse-width modulated DC-AC inverters. Detailed analysis of phase compensation on system stability is provided, and conditions for the design of phase compensation are derived. The experimental results under different loads and load changes show that the proposed scheme can achieve high tracking accuracy, low total harmonic distortion, and fast dynamic response.