A method and system for estimating DC bus voltages of series connected h-bridge cells of a multi-level cascaded inverter comprises comparing the switching reference waveform with a set of pre-defined constants to determine time periods of switching activity in each of the h-bridge cells, encoding output of the comparison to generate an output indicating non-zero voltage level number of the multi-level PWM output at various time instants, checking whether a current sample value of the multi-level PWM output is greater than an estimated threshold voltage of a voltage level defined by current encoder output, estimating a net dc voltage of said voltage level, estimating a dc bus voltage of an h-bridge cell corresponding to said voltage level by subtracting a net dc voltage of a previous voltage level from the net dc voltage of said voltage level.
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