A Study on Effects of Offset Error during Phase Angle Detection in Grid-tied Single-phase Inverters based on SRF-PLL

SRF-PLL을 이용한 계통연계형 단상 인버터의 전원 위상각 검출시 옵셋 오차 영향에 관한 연구

Kwon, Young;Seong, Ui-Seok;Hwang, Seon-Hwan

  • Received : 2015.08.05
  • Accepted : 2015.09.14
  • Published : 2015.10.30


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.


Grid-Tied Single-Phase Inverter;Offset Error;Scale Error;PR Controller;SRF-PLL


  1. H. E. Park, E. S. Kim, J. H. Song, "A SRF Power Flow Control Method for Grid-Connected Single-Phase Inverter Systems," JIEIE, vol. 24, no. 5, pp. 129-135, May. 2010.
  2. J. S. Choi, J. S. Ko, D. H. Chung, "Development of Novel Algorithm for Anti-Islanding of Grid-Connected PV Inverter," JIEIE, vol. 25, no. 10, pp. 76-86, Oct. 2011.
  3. T. V. Sreenivas, R. J. Niederjohn, "Zero-Crossing Based Spectral Analysis and SVD Spectral Analysis for Formant Frequency Estimation in Noise," IEEE Trans. Signal Pro., vol. 40, no. 2, pp. 282-293, Feb. 1992.
  4. M. K. Ghartemani, M. R. Iravani, "A Method for Synchronization of Power Electronic Converters in Polluted and Variable-Frequency Environments," IEEE Trans. Power Sys., vol. 19, no. 3, pp. 1263-1270, Aug. 2004.
  5. M. Ciobotaru, R. Teodorescu, and F. Blaabjerg, "A new single-phase PLL structure based on second order generalized integrator," in Proc. PESC, 2006, pp.1-6.
  6. M. Karimi-Ghartemani, S. A. Khajehoddin, P. K. Jain, A. Bakhshai, and M. Mojiri, "Addressing DC component in PLL and notch filter algorithms," IEEE Trans. Power Electron., vol. 27, no. 1, pp. 78-86, Jan. 2012.
  7. S. Golestan, M. Monfared, F. D. Freijedo, J. M. Guerrero, "Performance Improvement of a Prefiltered Synchronous- Reference-Frame PLL by Using a PID-Type Loop Filter," IEEE Trans. Ind. Electron., vol. 61, no. 7, pp. 3469-3479, Jul. 2014.
  8. M. K. Ghartemani, "A Unifying Approach to Single-Phase Synchronous Reference Frame PLLs," IEEE Trans. Power Electron., vol. 28, no. 10, pp. 4550-4556, Oct. 2013.
  9. S. H. Hwang, L. Liu, H. Li, J. M. Kim, "DC offset error compensation for synchronous reference frame PLL in single-phase grid-connected converters," IEEE Trans. Power Electron., vol. 27, no. 8, pp. 3467-3471, April 2012.
  10. S. H. Hwang, Y. G. Hwang, S. K. Kwon, "A Study on Current Ripple Reduction Due to Offset Error in SRF-PLL for Single-phase Grid-connected Inverters," JIEIE, vol. 28, no. 11, pp. 68-76, Nov. 2014.
  11. F. O. Martinz, K. C. M. D. Carvalho, N. R. N. Ama, W. Komatsu, Lourenco, "Optimized Tuning Method of Stationary Frame Proportional Resonant Current Controllers," in Proc. IPEC, 2014, pp. 2988-2995.
  12. H. Wang, W. Zhang, J. Hu, Y. He, "Design and Optimization of Proportional Resonant Controller for Rotor Current of a Wind Turbine Driven DFIG," in Proc. ICEMS, 2008, pp. 2502-2506.