LAUSR

Purpose This paper aims to develop a method for a unified model of pulse width modulation (PWM) voltage source inverters (VSI). This generic method, based on a common and easy-to-use carrier-based modulation, allows to generate the exhaustive solution set for a given PWM-VSI. Design/methodology/approach The use of the generalized inverse theory is developed to express the PWM solution set for the duty cycle. Indeed, the infinite number of PWM solutions is demonstrated. To explore this solution set, the unified model described exhibits degrees of freedom. The admissible margins to set the degree of freedom are highlighted. Some experimental results are presented. Findings It is demonstrated how the degree of freedom can be directly connected with efficiency indicators such as common mode voltage, inverter linearity and switching losses. The expression of the PWM solution set boundaries is clearly expressed. Research limitations/implications Further studies should explore how the degree of freedom can be connected with parameters associated with the current (and not the voltage as described in this paper). Practical implications The paper includes implications for the development of a more generic approach for PWM multilevel VSI. Originality/value This paper fulfils a mathematical frame to ease the expression of PWM scheme.