Harmonic modeling of single-phase three-level hysteresis inverters

The paper derives a closed-form analytical approximation of the output current harmonic spectrum for the three-level single-phase inverters under the action of hysteresis current control. The error current harmonic spectrum is directly calculated from the system and controller parameters. The analytical approach consists of deriving the instantaneous frequency of the error current and then approximating the error current by a frequency-modulated triangular signal. The error current harmonic spectrum reduces to a frequency convolution of two series of Bessel functions of the first kind. A truncation simplification of the output harmonic profile that is suitable for numerical calculations is also provided. MATLAB\Simulink
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studies are presented to demonstrate the validity and accuracy of the proposed model.