this invention is a multi - coupled power conversion system including power converters 114 and 124 connected in parallel through reactors 105 , with each power converter converting a d . c . voltage into an a . c . voltage by means of automatic turn - off switching devices which turn on and off in response to on / off commands . the system includes a spatial voltage vector calculator 101 which , in order to provide the on / off commands for the parallel - connected power converters 114 and 124 , selects multiple spatial voltage vectors in accordance with the amplitude vc and phase θ of the command of the a . c . voltage to be produced by the power converters 114 and 124 and calculates vector output times , a vector permutation device 102 which determines two sets of the order of generation of the selected spatial voltage vectors , and pwm generators 113 and 123 which generate the on / off commands in response to the output of said vector permutation device 102 . the system further includes a means of controlling the output voltages of the power converters 114 and 124 by providing the pwm generators 113 and 123 with two sets of spatial voltage vector series of different orders determined by the vector permutation device 102 .