D. Alternative power generation (PV, wind)
PV system design, wind power curves, wind turbine types 1-4.
Lessons
PV system design — modules, strings, NEC 690 / 705 sizing
Architectures: string / multi-string / central / micro / DC-optimizer. Module STC: V_oc, I_sc, V_mpp; T-coefficients. NEC 690.7 max string V at ASHRAE 2% cold; 690.8 I_max=1.25·I_sc, conductor + OCPD 1.56·I_sc; 690.12 rapid shutdown 30 V / 30 s; 705.12 120% interconnection rule. UL 1741 + IEEE 1547 anti-islanding + smart inverter. Cap factor 12-32%; LCOE $30-200/MWh; ITC 30%.
Wind power curve and generator topologies
P = ½·ρ·A·v³·C_p, Betz limit, tip-speed ratio, pitch control, and Types 1–4 (SCIG → WRIG+R → DFIG → full-converter PMSG).
Wind turbine Types 1-4 — SCIG / WRIG / DFIG / Full-converter PMSG
P_wind = ½·ρ·A·v³; Betz limit C_p ≤ 0.593; modern C_p ≈ 0.45-0.50. Type 1 SCIG fixed (1990s); Type 2 WRIG +rotor R, ±10% slip; Type 3 DFIG partial converter (25-30% MVA), ±30% sync (dominant 2005-2020); Type 4 PMSG full converter (100% MVA, direct-drive, all offshore + new onshore since 2018). IEEE 2800-2022 + FERC 901 (2024) for IBR grid-code. Grid-forming Type 4 future. Capacity factor 25-50%.