Sang-Hyeon Lee and Kyo-Beum Lee, "Analysis and Comparison of Low-Order Harmonic Reduction Methods for Grid-Connected Inverters," in Proc. ICEE Conf., 2022. > Paper

This paper presents analysis and comparison of different methods to reduce the loworder harmonics for grid-connected inverters. The low-order 

harmonics are represented as 5th and 7th harmonics. They are included in the grid currents when different kinds of loads or non-linear loads are 

connected to point of common coupling. These low-order harmonics should be reduced because they cause reduced efficiency in power converters. 

Various methods to reduce the low-order harmonics have been introduced. These methods can be divided into two groups. One is to control the 

harmonics to zero with proportional resonant (PR) controller in the stationary reference frame. The other one is to control the harmonics to zero with 

proportional integral (PI) controller in the synchronous reference frame. The PR controller-based method shows better performance than the PI 

controller-based method in the harmonic reduction. However, the improved PI controller-based method with band pass filter (BPF) shows almost the 

same performance as PR controller-based method. In this paper, different methods for reducing the low-order harmonics are analyzed and compared. Simulation results are used to compare the performance of each method.