In the design of integrated drives, consisting of motor, power converter and controller, it can be advantageous to model the transient performance prior to fully implementing the hardware. This enables motor design parameters and control strategies to be evaluated prior to implementation. One possible approach to this would be to accurately synthesise the converter waveforms in the model . When considering pulse width modulated (PWM) inverter fed machines this task becomes complex due to the nature of the waveforms being used as the switching pattern is dependant on both voltage and frequency. A simplified approach is used where the waveforms are taken to be sinusoidal at all times, balanced load conditions are also assumed. This can be justified in PWM fed machines as the waveforms produced are close to sinusoidal. Also the harmonics that are produced tend to be of high order contributing to rotor losses but not significantly to torque production.
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