Instantaneous Average Prediction of the Currents in a PWM-Controlled Two-Level Converter

In this paper, a new method is applied to predict the average value of the phase currents of a two-level voltage source converter. The method uses a suitable model of the converter, the modulation method, and the measurement. The samples given by the analog-to-digital converter (ADC) are used to predict the time progress of the currents in every switching cycle and then calculate its average. This allows removal of the delay introduced by filtering and avoids aliasing in the measurements. The average prediction is contrasted with the pulse width modulation (PWM) synchronous sampling method and the sigma-delta ADC with a moving average filter. Applied to a load observer, the method effectively reduces its estimation error. The findings are verified experimentally.