title: Improvement of the grid-connect current quality using novel proportional-integral controller for photovoltaic inverters.
abstract: Precise control of the grid-connected current is a challenge in photovoltaic inverter research. Traditional Proportional-Integral (PI) control technology cannot eliminate steady-state error when tracking the sinusoidal signal from the grid, which results in a very high total harmonic distortion in the grid-connected current. A novel PI controller has been developed in this paper, in which the sinusoidal wave is discretized into an N-step input signal that is decided by the control frequency to eliminate the steady state error of the system. The effect of periodical error caused by the dead zone of the power switch and conduction voltage drop can be avoided; the current tracking accuracy and current harmonic content can also be improved. Based on the proposed PI controller, a 700 W photovoltaic grid-connected inverter is developed and validated. The improvement has been demonstrated through experimental results.
authors.affiliation: School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China.
authors.forename: Libing
authors.initials: L
authors.lastname: Bai
authors.affiliation: School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang