A Coupled Reluctance Network Approach to Self-Sensing

Although self-sensing is not a new concept and the topic has been researched in the past, it remains a challenge. Self-sensing performance is degraded due to problems such as magnetic cross-coupling, eddy currents, saturation and high losses, to name but a few. In this paper the amplitude modulation self-sensing approach using the switching amplifier ripple as high frequency source is adopted. A coupled reluctance network model (RNM) is developed which models the coil impedance at the switching frequency. The model is refined, to accurately include the mentioned degrading effects, and incorporated into a multiple input multiple output (MIMO) parameter estimation self-sensing scheme. Simulation results show that it is possible to address saturation and magnetic cross-coupling with the RNM incorporated into a MIMO parameter estimation scheme. System sensitivity levels satisfactory for long term operation are achieved.