With the accelerated development in semiconductor power devices along with the dictated rigorous reliability standards in some industrial sectors, the application of a medium-voltage high-power multiphase induction machine with multiple three-phase windings is now considered as a leading technology in high-power safety-critical applications. This paper proposes a parameter-independent postfault control scheme for an asymmetrical six-phase induction machine based on simple scalar V/f control, which can successfully ensure the most common postfault scenarios used in this respect, namely, equal stator copper loss and minimum copper loss modes. Moreover, the proposed controller can effectively be used in either open-loop or closed-loop speed control modes. The proposed controller is experimentally validated using a 1.5-kW prototype induction machine. The effect of the neutral arrangement on the dynamic performance is also explored.

Multiphase machines are commonly analyzed using vector space decomposition modeling technique, where the original phase variables are decomposed into multiple orthogonal subspaces. The machine torque production and, therefore, its dynamic response are mainly decided from the α-β fundamental subspace. In the available literature, other non-fundamental subspaces are commonly regarded as non-flux/torque producing subspaces, while mainly contributing to extra winding joule losses. Although the primitive harmonic-free models are usually assumed for these secondary subspaces in asymmetrical six-phase induction machines, a clear evidence to include or discard the effect of the low-order space harmonics of the air gap flux distribution under different neutral configurations has not been established so far. To this end, this paper investigates the effect of the induced air gap harmonics mapped to the x-y and zero subspaces on the dynamic modeling and, hence, the dynamic response of an asymmetrical six-phase induction machine. An improved space harmonic model is, then, proposed to better explore/simulate their effect under both healthy as well as fault conditions. The proposed model is experimentally validated using a 1.5kW prototype induction machine.

This article presents the operation of onboard integrated battery chargers tied to a nine-phase EV-drive train, shedding light on the charging performance during the postfault operation, when one or more faulty inverter legs are disconnected. The objective in that case is to ensure balanced grid currents, while maintaining minimum machine losses at zero average torque production. The proposed concept requires a minimalistic change from a control structure perspective to switch between the pre- and postfault cases. Limitations and fault cases are discussed and corroborated with experimental tests on a 1.5-kW prototype.The derived concept is parameter independent and applicable to nine-phase drives, irrespective of the type of rotor used.

This paper is concerned to design of direct coupled solar water pumping system without using batteries. Technical, economic and environmental parameters are considered in the design procedures. Performance evaluation of solar water pumping system is studied using three expressions; yield factor (YF), wire to water energy efficiency (WWEE) and system performance index (SPI). A full monitoring system is presented to evaluate the operation of the system. The proposed monitoring system measures a real time data of system parameters. A case study of 45 kWp solar water pumping system in El Wahat, Egypt is studied. The recorded data using the monitoring system shows that the average daily water volume was 788 m3 over one year. The maximum output water volume was 887 m3 in summer with yield factor 5 (kWh/kWp/day).