Four-leg converters are used in several applications that require neutral wire (distributed generation systems, APF). To act on converter switches, three-dimensional space vector pulse width modulation (3-DSVPWM) is usually used. This modulation generates pulses according to the reference voltages issued from a controller. In this paper, a current predictive controller is proposed for 4-leg voltage-source converter. The proposed controller generates control signals without voltage reference calculation. To do this task, geometrical properties of the predicted-current projections are used.

A new technique for the determination of space charge profiles in insulating polymers is proposed. Based on the evolution of an existing thermal wave technique called Focused Laser Intensity Modulation Method ((F)LIMM), it allows non-contact measurements on thin films exhibiting an internal charge to be studied. An electrostatic model taking into account the new sample-cell geometry proposed was first developed. It has been shown, in particular, that it was theoretically possible to calculate the internal charge from experimental measurements while allowing an evaluation of the air layer appearing between the sample and the electrode when non-contact measurements are performed. These predictions were confirmed by an experimental implementation for two thin polymer samples (25 μm-polyvinylidenefluoride and 50 μm-polytetrafluoroethylene (PTFE)) used as tests. In these cases, minimum air-layer thickness was determined with an accuracy of 3% and 20%, respectively, depending on the signal-to-noise ratio during the experimental procedure. In order to illustrate the reachable possibilities of this technique, 2D and 3D cartographies of a negative space charge implanted by electron beam within the PTFE test sample were depicted: like in conventional (F)LIMM, a multidimensional representation of a selectively implanted charge remains possible at a few microns depth, but using a non-contacting way of measurement.