Sampling of discontinuous voltage and current signals in electrical drives: a system approach

Various methods for the sampling of voltage and current signals in electric drives are analyzed and compared. Two new methods for sampling the discontinuous voltage and current signals in a PWM inverter-fed drive are proposed. The methods are based on sampling the instantaneous values and locally averaged values (over one carrier period) of signals. Analytical expressions for adjustment of digital current regulators and achievable bandwidths with the various sampling methods are derived. The results are experimentally verified.