Converters & rectifiers
Diode and thyristor rectifiers, DC output equations, ripple, line harmonics.
Lessons
Rectifier waveforms — half-wave, full-wave, 3-φ 6-pulse, SCR control
V_dc equations, ripple factor, firing-angle control, and 6-pulse line-current harmonics (5th, 7th, 11th, 13th).
Inverter PWM — sinusoidal PWM, modulation index, SVPWM
How comparing a sine with a triangle generates a clean AC sine at the output; m_a / m_f, over-modulation, and the 3-φ third-harmonic injection that boosts V_LL by 15 %.
DC-DC converters — buck, boost, buck-boost
Three classical non-isolated topologies with their CCM transfer functions, CCM vs DCM operation, and L/C sizing for target ripple.
Photovoltaic I-V curves and MPPT
PV cell I-V shape, MPP location, irradiance + temperature effects, and Perturb-and-Observe / Incremental-Conductance MPPT algorithms.
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).
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 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%.
Microgrid architecture — grid-connected vs islanded, IEEE 2030.7
DOE/IEEE 2030.7 definition: bounded local DERs + loads + PCC, with islanding capability. Components: PV/battery/gas-gen/fuel-cell + tiered loads + PCC + static transfer switch + MEMS controller. Two modes: grid-connected (utility V/f) vs islanded (grid-forming DER self-regulates). Hierarchical control: primary droop / secondary MEMS / tertiary economic. AC vs DC vs hybrid architectures. IEEE 2030.7/2030.8/1547; FERC 2222. Examples: Princeton, Borrego Springs, DoD bases.
EV charging — Level 1, Level 2, DC fast charging
Three levels by power: L1 (120 V, 1.4 kW), L2 (208-240 V, 3-19 kW), DCFC (DC, 50-400 kW with 1 MW emerging). Connectors: J1772 (universal AC), CCS (combined AC+DC), NACS / SAE J3400 (Tesla, adopted by all majors 2023-25), CHAdeMO (declining). Vehicle: OBC + battery + BMS. Protocols: pilot PWM + ISO 15118 + OCPP. NEC 625 (80% continuous, 40 A min L2, CCID GFCI). Grid impact: DCFC plaza = MV service + storage. V2H/V2G future.
Grid-forming inverters — IEEE 2800 / P2800.2, FERC 901
High-IBR grids lose synchronous inertia (H_sys 4-5 → 1-2 s) + stiffness (SCR < 3 destabilises GFL). GFL: PLL current source. GFM: voltage source, sets own V/f, synthetic H_eff 1-5 s + damping + voltage stiffness + black-start + fault current 2-4 pu. Three approaches: droop, VSM, VOC. IEEE 2800-2022 + P2800.2 (in dev) + FERC 901 (2024). AEMO mandates >30 MW. Hornsdale 100 MW, Kapolei 185 MW pilots.