Then, to simultaneously synthesise the output voltage and the input current vectors,
common switching states ±9,±7,±1and±3 are selected. From two switching
states with the same number but opposite polarity, only one should be used. If the duty
cycle is positive, the switching state with a positive polarity is selected; otherwise,
the one with a negative polarity is selected. The required modulation duty cycles for
the switching configurations I, II, III and IV are given by Eqs. (2.47)–(2.50) [23]: