Power Electronics

Switching semiconductors that convert and control electrical power. The technology inside every charger, drive, inverter and power supply. Thyristor devices (SCR, TRIAC, DIAC), transistor switches (MOSFET, IGBT), rectifiers, inverters, DC–DC choppers, converter topologies, PWM and complete motor drives.

• SCR — The silicon-controlled rectifier (thyristor) is a latching switch turned on by a gate pulse and off only when its current falls to zero. Learn its structure, triggering, ratings, protection and phase-controlled rectifiers.
• TRIAC — A TRIAC is effectively two SCRs back-to-back with a single gate, conducting in both directions. Learn its quadrants, phase-control dimmers, zero-cross and burst-fire control, snubbers and solid-state relays.
• DIAC — The DIAC is a symmetrical breakover device that fires a sharp pulse when its voltage reaches ~30 V. Learn its I–V characteristic, negative resistance, and how RC–DIAC networks set a TRIAC's firing angle in classic dimmers.
• MOSFET — The power MOSFET is the fast, voltage-driven switch inside most converters below ~600 V. Learn threshold and R_DS(on), conduction and switching losses, gate charge and drivers, the body diode, SOA and thermal design.
• IGBT — The IGBT combines a MOSFET's easy gate with a bipolar transistor's low conduction drop at high voltage. Learn V_CE(sat), switching energies and tail current, loss and thermal calculations, modules, short-circuit protection and IGBT vs SiC.
• Rectifiers — Rectifiers convert AC to DC. Learn half-wave, centre-tapped and bridge single-phase circuits, three-phase bridges, capacitor filtering and ripple, PIV ratings, and the design of a complete linear DC supply.
• Inverters — Inverters convert DC into AC of controllable voltage and frequency. Learn half- and full-bridge topologies, square-wave and sinusoidal PWM, modulation index, three-phase inverters, dead time, output filters and grid-tied operation.
• Choppers — Choppers are DC–DC converters that 'chop' a DC voltage with a fast switch and filter it. Learn buck, boost and buck-boost conversion ratios, inductor and capacitor sizing, continuous vs discontinuous conduction, and efficiency.
• Converters — The full family of power converters: AC–DC, DC–DC (isolated and non-isolated), DC–AC and AC–AC. Learn how flyback, forward, LLC, dual-active-bridge, cycloconverter and matrix topologies work and how to choose one.
• PWM — Pulse-width modulation controls average power by switching fully on and off with a variable duty cycle. Learn duty, frequency and resolution, carrier-based PWM, filtering, dead time, and how to choose PWM frequency for LEDs, motors and converters.
• Motor Drives — A drive combines power electronics and control to run a motor at any speed and torque. Learn VFD architecture, V/f and vector control, braking and regeneration, the affinity laws, drive sizing and installation issues.