Analysis of the duality of three phase PWM converters with DC voltage link and DC current link

The duality of three-phase pulse-width modulation (PWM) converters with DC current and DC voltage links is analyzed by means of space-vector calculus for the example of a forced commutated rectifier system. The power-invariant transformation of the converter phase voltages or line currents into complex image quantities (space vectors) allows the presentation of the converter system as a complex space-vector voltage source or current source; its initial value is defined by the switching status of the converter system. The modulation principles (e.g., optimized pulse patterns) known from converters using DC voltage link systems, the guidelines concerning the dimensioning of power circuit components, and considerations relating to control are applied to the theory governing DC current link converters.<>