POWER CONVERTER WITH DISTRIBUTED CELL CONTROL

摘要

In a method for controlling a Voltage Source Converter having at least one phase leg comprising a series connection of switching elements, in which each said element has at least two semiconductor devices of turn-off type, at least two free-wheeling diodes connected in parallel therewith and at least one energy storing capacitor, each said switching element is controlled according to a Pulse Width Modulation pattern so that each switching element is switched to change between applying a zero voltage and the voltage across its capacitor across its terminals each time a saw tooth voltage wave for that switching element crosses a reference alternating voltage belonging to that switching element.