| Title |
A Study on Effects of Offset Error during Phase Angle Detection in Grid-tied Single-phase Inverters based on SRF-PLL |
| Authors |
Young Kwon ; Ui-Seok Seong ; Seon-Hwan Hwang |
| DOI |
http://dx.doi.org/10.5207/JIEIE.2015.29.10.073 |
| Keywords |
Grid-Tied Single-Phase Inverter, Offset Error, Scale Error, PR Controller, SRF-PLL |
| Abstract |
This paper proposes an ripple reduction algorithm and analyzes the effects of offset and scale errors generated by voltage sensor while measuring grid voltage in grid-tied single-phase inverters.Generally, the grid-connected inverter needs to detect the phase angle information by measuring grid voltage for synchronization, so that the single-phase inverter can be accurately driven based on estimated phase angle information. However, offset and scale errors are inevitably generated owing to the non-linear characteristics of voltage sensor and these errors affect that the phase angle includes 1st harmonic component under using SRF-PLL(Synchronous Reference Frame ? Phase Locked Loop) system for detecting grid phase angle. Also, the performance of the overall system is degraded from the distorted phase angle including the specific harmonic component. As a result, in this paper, offset and scale error due to the voltage sensor in single-phase grid connected inverter under SRF-PLL is analyzed in detail and proportional resonant controller is used to reduce the ripples caused by the offset error. Especially, the integrator output of PI(Proportional Integral) controller in SRF-PLL is selected as an input signal of the proportional resonant controller. Simulation and experiment are performed to verify the effectiveness of the proposed algorithm. |