A simple method for the THD improvement of a MV arbitrary waveform generators

The development of an arbitrary MV generator (AMVG) is a quite complex task. The level of voltage amplitude requires a careful analysis of any possible solutions at the level of its design, by finding the best tradeoff between performance and cost. In this perspective, a very attractive solution is represented by the way followed by the authors, in which the cost of the AMVG has been kept low thanks to a simple architecture based on few commercial devices. The performances have been increased by means of suitable pre-processing of the input signal. This approach has been yet applied with the aim to extend the generator bandwidth. In this paper the same approach has been applied also to the compensation of the non-linear effect mainly introduced by the step-up transformer used inside the AMVG. The method requires a two-step procedure: first of all a sinusoidal signal is applied to the input of the AMVG and the corresponding output signal is acquired and its spectrum computed. A new input signal able to produce the partial compensation of the unwanted harmonics introduced by the non-linearity of the system is then synthetized. Despite its simplicity and the adoption of a simple modeling of the system, the experimental results prove that it is possible to reduce about three times the THD of the system.