The Transactions of the Korean Institute of Power Electronics (전력전자학회논문지)

The Korean Institute of Power Electronics (전력전자학회)
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Grid Voltage Estimation Scheme without Phase Delay in Voltage-sensorless Control of a Grid-connected Inverter

전압센서를 사용하지 않는 계통연계 인버터의 제어 및 위상지연을 개선한 계통전압 추정 기법

  • Kim, Hyun-Sou (Dept. of Electrical and Information Engineering, Seoul National University of Science and Technology) ;
  • Kim, Kyeong-Hwa (Dept. of Electrical and Information Engineering, Seoul National University of Science and Technology)
  • Received : 2016.09.30
  • Accepted : 2016.11.16
  • Published : 2017.02.20
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Abstract

This study proposes a grid voltage estimation scheme without a phase delay in the voltage-sensorless control of a grid-connected inverter to enhance its economic feasibility, such as manufacturing cost and system complexity. The proposed scheme estimates grid voltages using a disturbance observer (DOB)-based current controller to control the grid-connected inverter without grid-side voltage sensors. The proposed voltage-sensorless control scheme can be applied successfully to grid-connected inverters, which should be operated with synchronization to the grid, considering the phase angle of the grid can be effectively detected through estimating the grid voltages by DOB. However, a problem associated with the phase delay in estimated grid voltages remains because the DOB has dynamic behavior similar to low-pass filter. Hence, the estimated grid voltages are compensated by a phase lead compensator to overcome the limitation. The effectiveness of the proposed control and estimation schemes is proven through simulations and experiments using a 2 kVA prototype inverter.

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References

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