This paper presents a digital twin (DT)-based fault recovery method for power electronic converter systems. The method employs a prediction accelerator with a DT model for each subsystem of the converter system and feeds back the predicted system state to the controller. The paper demonstrates that the method can recover from faults such as load and input voltage variations in realtime and can integrate with hardware in the loop for future applications and comparing with other advanced control methods. The paper also highlights the benefits of the method in terms of scalability, replaceability and modularity for power electronic systems.

This study evaluates the full-linear transfer function model for the dual-active-bridge with the impedance-based small-signal averaged model. Besides, for the better implementation on the FPGA, a discrete-time state-space model has been developed. The model matching comparison of non-linear, full-linear, switching and state-space models has been done. In this paper, each mode of single and cascade connection of dual active bridge have been evaluated and compared.

Employing high frequency (HF) transformer in DC-DC converter is a popular strategy in power electronic industry. Equivalent circuit model of transformer in HF Dual Active Bridge (DAB) converters is investigated along with its impact on power transfer characteristic for Single Phase Shift (SPS) and Extended Phase Shift (EPS) modulation. Equivalent branches of magnetizing inductance allocated in primary and secondary side can inject the inductive current at switching instants to extend Zero Voltage Switching (ZVS) range. ZVS maps are proposed. Based on the power transfer characteristics and ZVS maps, an Advanced Extended Phase Shift (AEPS) modulation method with modified coupling relationship for phase shift is proposed to reduce the current stress and improve the voltage utilization. Finally, AEPS modulation is implemented in PLECS simulations to verify the analyzation presented.

The Current Source Inverters (CSIs) are an alternative to Voltage Source Inverters (VSIs) for electric motor applications. Despite the advantageous characteristics of intrinsic voltage boost capability, absence of electrolytic capacitors and reduced machine voltage stress, the increased component count and the need of a pre-stage for the inductor current control have limited the adoption. For some applications which have to operate always above a base speed (e.g. pumps, actuators, fans), single-stage CSI converter with improved efficiencies have been proposed. Owing to the advantage of the direct measurement of the terminal voltage, a simple and robust sensorless control is proposed for a single-stage CSI converter. Simulations on a SiC-based CSI7 converter driving a Permanent Magnet Synchronous Machine (PMSM) confirm the validity of the proposed control, potentially paving the way to a larger adoption of the CSI7 topology for motor drive application.

In the framework of the More Electric Aircraft (MEA), weight reduction and energy efficiency constitute the key figures. In addition to these requirements, the safety and the continuity of operation is of critical importance. These sets of desired feature are in disagreement, because the redundancy needed to guarantee the safety of operation implies necessarily in additional weight. Several concepts of the electrical power distribution systems have been proposed, in this manuscript, an approach based on the widespread use of multi-port power converters both for the DC/DC and for the DC/AC stages is proposed. These two technologies allows for a ring distribution of the electrical power whereas the galvanic isolation is still kept. Simulation and experimental results show the feasibility of the concept in common and fault operation conditions.

This paper proposes a semi-flooded cooling concept for a high speed machine design. The electrical machine considered is for an aircraft starter-generator system where power density and efficiency are crucial. In order to achieve the high power density permanent magnet machine, a direct oil cooling strategy for the machine stator is adopted. A stator oil sleeve is designed to separate the machine into an oil-flooded stator chamber and an oil-free rotor chamber to avoid windage loss due to the high rotor speed. Different materials, Carbon Fiber (CF) and E-glass fiber (GF) are considered for the oil-sleeve design. Implications of the aforementioned materials on the structural design are investigated and optimized accordingly using finite element methods. It is shown that the oil sleeve made of CF provides structural capability with a minimum sleeve thickness. However the sleeve made from GF has the benefit of having no electrical conductivity. Both oil sleeves are made and the GF sleeve is successfully applied to the machine and tested.

This paper presents the trade-off analysis and design of a high power-density machine for industrial pump applications. The developed permanent magnet synchronous machine drives an electric, oil flooded pump. Different slot/pole combination and winding configuration have been investigated in order to identify the optimal combination that satisfies the electromagnetic and thermal constraint while keeping the losses as small as possible. Several strategies such as the use of the Cobalt iron material for the stator core lamination and the adoption of Halbach array have been investigated in this work to improve the performance capabilities of the designed machine. The electromagnetic performances have been evaluated by using a finite element method. Thermal behaviour has been determined using a lumped parameter network. The outcome of the thermal analysis helped to identify the optimal cooling configurations. The final results are presented highlighting the achieved design targets.

Higher voltage DC distribution systems are being used or considered for aircraft, ship and EV/HEV automotive applications and are required for photovoltaic (PV) systems. Fault detection and location in these systems can be very challenging and electrical arcs can cause significant damage such as electrical fires. Therefore, detecting arc faults for DC systems is receiving considerable attention in the research community. Non-contact arc characteristics and arc detection mechanisms in DC systems are addressed in this paper through theoretical development and experimental tests.