In this paper, the authors present the modelling of the impedance variation of an inverter DC bus. Modelling is done by application of the PEEC method (partial element equivalent circuit) with an additional method for computing the local charge density (analytical formulas) in order to give the local capacity. This method has been implemented so as to extract the behaviour of the local charge density, specifically for busbar structure. Results obtained in the case of an approached busbar equivalent geometry are shown. A quantification of the edges importance for the charge repartition is presented, and so its link with the HF local capacitor influence. Moreover simulations of the values of the global DC bus impedance versus frequency are compared to measures.

Nonlinear Observer Design for Load Torque Estimation of Induction Motors

Solar-powered pumping systems using series pumps are commonly applied in the delivery of water to remote agricultural regions, particularly in hilly tropical terrain. The synchronization of these pumps typically depends on reliable communication; however, dense vegetation, elevation changes, and weather conditions often disrupt signals. To address these limitations, a fully decentralized, communication-free control system is proposed. Each pumping station operates independently while maintaining synchronized operation through emulated neighbor sensing. The system applies a discrete-time control algorithm with virtual sensing that estimates neighboring pump statuses. Each station consists of a solar photovoltaic (PV) array, variable-speed drive, variable inlet valve, reserve tank, and local control unit. The controller adjusts the valve positions and pump power based on real-time water level measurements and virtual neighbor sensing. The simulation results across four scenarios, including clear sky, cloudy conditions, temporary outage, and varied irradiance, demonstrated steady-state operation with no water overflow or shortage and a steady-state error less than 4% for 3 m³ transfer. The error decreased as the average power increased. The proposed method maintained system functionality under simulated power outage and variable irradiance, confirming its suitability for remote agricultural areas where communication infrastructure is limited.

J3eA, Journal sur l enseignement des sciences et technologies de l information et des systèmes