Power Flow Control of a Single-Stage AC-AC Solid-State Transformer for AC Distribution System
Recently, there has been a growing demand for bidirectional ac-ac solid-state transformers (SST) that can meet both active and reactive power demands of the low- and medium-voltage ac distribution grids. Single-stage SSTs can be of significant interest in these grids because they employ fewer passive components besides offering a simpler power flow control. In this paper, a closed-loop feed-forward PQ controller is investigated for a single-stage bidirectional ac-ac SST that consists of two H-bridge cells and a high-frequency transformer in a dual active bridge (DAB) configuration. Single phase-shift PWM is used to meet the active and reactive powers demands of the single-phase ac grids. A second-order generalized integrator (SOGI) in conjunction with a phase-locked loop (PLL) ensures proper grid synchronization. The operation of the controller is validated through simulations performed on a 3.6 kVA, 120/120 V SST. With the designed controller, the SST can meet 20% of its rated kVA as reactive power without exceeding the maximum allowable total harmonic distortion (THD) injection to the grid as per the IEEE 519-2014 standard.
A. Sharma et al., "Power Flow Control of a Single-Stage AC-AC Solid-State Transformer for AC Distribution System," 2022 IEEE Power and Energy Conference at Illinois, PECI 2022, Institute of Electrical and Electronics Engineers (IEEE), Jan 2022.
The definitive version is available at https://doi.org/10.1109/PECI54197.2022.9744006
Electrical and Computer Engineering
Keywords and Phrases
AC Distribution Systems; Active Power; Dual Active Bridge (DAB) Converter; Reactive Power; Solid-State Transformer (SST); Variable Phase-Shift Control
International Standard Book Number (ISBN)
Article - Conference proceedings
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01 Jan 2022