A high performance space vector motor drive controller

Pulse width modulation (PWM) techniques are normally used to generate the required voltage or current waveforms to drive an AC motor. Space vector theory can be used to improve both the output crest voltage and the harmonic copper loss. The maximum output voltage based on the space theory is 1.155 times as large as the conventional sinusoidal modulation. It enables the inverter to feed the motor with a higher voltage than the easier suboscillation modulation method. Moreover, this method generates waveform in real-time and high precision when implemented in high performance processors. The new digital signal processor ADMC 330 from Analog Devices has been used for this purpose. Using this processor, an improved modulation technique for PWM voltage source inverter drives has been implemented. This technique also reduces the acoustic noise emitted in some specific working points by the AC machine due to the switching frequency. The acoustic noise is further reduced by using a random modulation strategy without actually raising the carrier frequency. This paper presents some first experimental results on the development of a DSP-based high performance space vector induction motor drive using the newly released XDMC330 DSP chip from Analog Devices. Specifically the implementation of the real-time generation of a three-phase PWM waveform using the space vector modulated scheme and the random modulation method are discussed