Measurement-grounded harmonic compliance of a modular 180 kW ultra-fast DC charger

This paper establishes a measurement-grounded framework for assessing harmonic compliance of a modular 180 kW ultra-fast DC charging system formed from six parallel 30 kW power supply modules (PSMs). The central scientific problem is determining how to make grid-compliance decisions for a scalable, multi-module charger when harmonic emissions vary with operating power and module count. Harmonic currents for 120 kW and 180 kW configurations are acquired using an IEC 61000–4-30 Class A analyser, independently cross-validated by an FFT measurement chain to the 50th order, and extended to the 100th order (5 kHz). An explicit uncertainty budget and repeated-session statistics establish the reliability of the compliance margin. Converter parameterisation and droop current-sharing analysis provide the physical and control context for the measured spectra; a cluster assessment propagates the measured per-charger spectrum to IEEE 519–2022 limits; and a compact regression model provides an operational screening estimate rather than replacing Class A measurement. THDi was measured as 8.8% at 120 kW and 8.2% at 180 kW, with the difference comparable to the reported session variability (±0.3% and ±0.4%, respectively), while the individual harmonic currents remain within IEC 61000–3-12 limits at Rsce = 33. The resulting framework connects charger operation, traceable harmonic measurement, uncertainty, and deployment-scale compliance in one experimentally anchored workflow.