Highly Dynamic Power Estimation and Efficiency Mapping Based on the Inverter’s Switching Cycle as Averaging Interval

Abstract:
This paper presents a highly dynamic estimation method for the power calculation of inverter-fed drive systems. Conventionally active power, RMS values and parameters derived from these quantities are determined by averaging the instantaneous (measured) quantities over the fundamental cycle of the periodic voltages and currents. However, if certain framework conditions are given, this averaging interval can be shortened to the switching cycle of the power inverter for inverter-fed applications. This results in novel power definitions approximating the conventional definitions during steady-state operation and additionally containing information from the instantaneous quantities in the case of dynamic balancing processes. These new approximation methods can be used to analyze highly dynamic systems, such as automotive or robotics applications, etc. Furthermore, the efficiency mapping procedure is drastically shortened or entire measurement series can be saved. An example of this is the evaluation of an efficiency map as part of a Worldwide harmonized Light vehicles Test Procedure (WLTP) that is being carried out anyway.