| Abstract |
Maximizing efficiency is one of the key design criteria for inverter-fed drives. The basis of this optimization process is a reliable measurement of the efficiency. The efficiency determination is in turn based on the cyclic calculation of the active power quantities based the fundamental period of the electrical quantities (voltages and currents) which is defined in detail in the relevant standards. For this reason, periodic voltages and currents are assumed to result in a steady-state condition of the drive if the standards are interpreted accurately. In many modern, highly dynamic applications (automotive, robotics, etc.), however, steady-state conditions are rare during normal operation. The electrical quantities change continuously both in magnitude and frequency and are characterized by transient behavior. In this paper, a novel highly dynamic measurement method for the approximation of the active power and efficiency is presented with regard to these dynamic applications. This methodology still approximates the conventional fundamental cycle-based definitions in the steady state, but also delivers additional dynamic information during transient balancing processes. The dynamic power analysis uses the switching period of the power electronics as averaging interval. For this reason, with regard to real-time measurements, a robust online switching cycle detection is an essential requirement to be able to perform this power analysis on a real-time capable power analyzer. |
