Multi-station smart charging in Vietnam: a quadratic-programming approach under the 2025 retail-tariff revision
DOI:
https://doi.org/10.56764/hpu2.jos.2026.5.02.41-55Abstract
We formulate day-ahead smart charging of an electric-vehicle fleet across multiple public charging stations in Vietnam as a convex quadratic program. The objective combines time-of-use tariff cost, quadratic peak-shaving, and ramp-smoothing; the constraints enforce per-EV connection-window bounds, per-EV energy delivery, per-station transformer caps, and feeder-level caps where stations share a primary distribution feeder. Station connector-mix and rate caps are drawn from OpenChargeMap and co-located PV from NASA POWER; arrival traces are transplanted from the real Shenzhen UrbanEV benchmark and recalibrated to the 2024–2025 VinFast fleet. The tariff reflects the 2025 retail-tariff restructuring (Decision 14/2025/QD-TTg). Across five seeds: F1, single-station Smart charging at α=0 cuts tariff cost 21.6% over uncontrolled charging, trading down to about 10% for a two-thirds peak-power reduction at higher peak-shaving weights; F2, on a 500-EV five-station feeder at the binding 1 MW cap the decentralised baselines are feasible in only 3 of 5 seeds while the coordinated solver stays feasible in all 5, at a 0.3–0.9% cost edge; F3, the 2025 flat-midday bracket cuts cost 14.7%; F4, OSQP solves the 500-EV instance in about 2 s. The study is a reproducible proof of concept for Vietnamese multi-station smart charging.
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