Simple current control without grid voltage sensor for traction solid-state transformer


This paper proposes a simple current control method without a grid voltage sensor for a rectifier of traction solid-state transformer. The proposed control scheme estimates the phase angle of grid voltage from the fundamental frequency current of the grid. The extracted phase signal is normalized to generate a sinusoidal current reference by adopting a scaling factor to achieve a unity gain. Since the proposed control method operates without the grid voltage sensor for power factor correction (PFC), it offers a cost-effective solution with a simple implementation structure. However, this method cannot guarantee its control performance under weak grid conditions, where the frequency of grid voltage often varies. Thus, the control parameters of the proposed method are discussed and analyzed to minimize performance degradation. To verify the feasibility of the proposed control method, simulations and experiments are carried out on a 2 kW single-phase PFC converter. The proposed method provides as much control performance as the conventional method, which uses the grid voltage sensor.

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This work was supported by a Grant (20RTRP–B146050–03) from the Railroad Technology Development Program funded by Ministry of Land, Infrastructure and Transport (MOLIT) of the Korean Government. This research was supported by the Human Resource Program (Grant No. 20194010201790) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea.

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Correspondence to Younghoon Cho.

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Yun, CG., Baek, S., Bu, H. et al. Simple current control without grid voltage sensor for traction solid-state transformer. J. Power Electron. (2021).

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  • Current control
  • Grid voltage sensor
  • Phase-locked loop
  • Power factor correction
  • Traction solid state transformer