Motors, Drives & Power Electronics

Making things move electrically. DC, stepper and brushless machines, modelling the DC motor, actuator and gearbox sizing, MOSFET switches and PWM, H-bridges and motor-drive electronics.

• DC Machines — DC motors and generators convert energy using a commutator. Learn back-EMF, the torque and speed equations, shunt/series/compound characteristics, starting current, speed control and why brushed DC still matters.
• Special Machines: Steppers, BLDC & Servos — Steppers, BLDC, servo, switched-reluctance, universal and linear motors — the machines behind printers, drones, robots and appliances. Learn how each works, its control method and how to choose between them.
• Modelling Electromechanical Systems: The DC Motor — The model at the heart of every motion system. Learn the permanent-magnet DC motor equations (electrical circuit, back-EMF, torque constant, mechanical dynamics), the torque–speed curve, stall torque and no-load speed, electrical and mechanical time constants, the transfer function from voltage to speed and position, power and efficiency, load torque and friction, and simulation by numerical integration — with a Python simulation of a 12 V step response.
• Actuator Selection & Motor/Gearbox Sizing — Choosing the right motor for the job. Learn actuator types (brushed DC, BLDC/PMSM servo, stepper, AC induction, linear motors, piezo, solenoids) and when to use each, move profiles and torque requirements (acceleration, friction, gravity), reflected inertia and gear ratios, inertia matching, RMS torque and thermal limits, speed–torque curve checks, gearbox backlash and efficiency, and a sizing workflow — with Python comparing gear ratios.
• 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.
• 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 Drivers: H-Bridges, PWM & Current Control — Power electronics that make motors move. Learn transistor switches (MOSFET, IGBT), the H-bridge and its switching states, PWM (unipolar vs bipolar), average voltage and current ripple, dead-time and shoot-through, freewheeling and braking, current sensing and current-loop control, stepper drivers and microstepping, three-phase BLDC inverters and commutation, losses and thermal design, and protection — with Python for PWM voltage, ripple and losses.