New method for obtaining SV-PWM patterns following an arbitrary reference

This paper presents a new method for the generation of SV-PWM patterns (space vector pulse width modulation) for three phase inverters, following an arbitrary reference. Instead of using the classical αβ reference axis, the method is based on a vector split up in two nonorthogonal axes, forming a 60° angle and coinciding with the fundamental state vectors of inverter. The method can be implemented by the use of a specific hardware circuit based on a PLD plus some analog circuitry (analog adders and comparators), or it can be used in fully digital controllers, based on digital processing techniques. The main advantage in both cases is the very fast response and the extremely low processor resources employed due to the simplification of transform matrix to convert the three phase system into a two component state vector. Such features allow the use of the method to obtain SV-PWM to generate arbitrary power waveforms with an extended bandwidth. The method is especially suitable for parallel active filter controllers. Simulated and experimental results obtained with a specific hardware circuit are presented in order to show the features of the method in high frequency applications.