METHOD FOR DETECTING OUTPUT CURRENT FROM SERIAL MULTIPLEX INVERTER

[Object] To detect an output current with a current detection delay shortened without decreasing accuracy of current detection. [Means to solve] In a serial multilevel inverter, in which each phase of a three-phase inverter is configured by connecting outputs of n-stage single-phase inverters in series, a current control (ACR) is performed by a detection current obtained by calculating a moving average of a sampling value of each phase output current of the three-phase inverter, and 2n carrier signals are shifted to a [360/2n] phase difference and are compared with a voltage command for a PWM control of the each single-phase inverter, a moving average width Tc is set to the same time as a PWM control cycle (1/2n of a cycle T carry of a carrier signal) and is synchronized with a peak of the carrier signal, and a sampling interval T smp is set to 1/2 of the moving average width Tc or less and is synchronized with the carrier signal. The current control cycle is set to the sampling interval T smp .