An improved simulation model of a brushless DC motor drive system for industrial applications

An accurate and simplified model of a brushless DC motor drive (BLMD) system is presented as a simulation tool for performance related studies in industrial drive applications and for system identification in controller design. The model relies on the single Fourier series expression for pulsewidth modulation (PWM), which includes the effects of inverter dead time as a substantial part of the switching period T/sub s/, in the current control loop. This simplified approach obviates the need for very small time steps (/spl sim/0.5% T/sub s/), in the search of PWM edge transitions within a switching interval, for accurate simulation. Substantial improvement in simulation speed is achieved (up to fiftyfold) with a beneficial saving in computation (CPU) resources. Model integrity is validated when simulation results are checked against actual BLMD test data for coherence. Subsequent model simulations illustrate the effect of inverter delay on the reduction of generated torque and power transfer.