A frequency approach for current loop modeling with a PWM converter

A new method based on a frequency approach is used to model a DC permanent magnet actuator driven by a pulsewidth modulated amplifier as a transfer function. This paper investigates two carriers used in industrial applications with analog or digital control. The accurate model presented takes into account the supply amplifier with the motor dynamics and includes the input control voltage sampling effect. Advantages and limitations of both carriers and control signals are discussed, and information about harmonic angles, magnitudes, and distortion are provided. The validation of the pulsewidth modulated model is carried out through simulations and experiments of both open and closed current loop systems with the effect of current ripple.