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This paper proposes a design methodology for power-dense and high-efficient electrohydraulic units (EHUs) that can be used to select design specifications for the electric machine (EM) for a given hydraulic machine (HM) architecture. The proposed method evaluates EHU performance considering both electric and hydraulic power losses. The compactness of the EHU is achieved by integrating an axial piston unit as HM inside a permanent magnet EM. The paper provides a sensitivity analysis for important EHU design specifications and discusses the best choices for reducing total mass and energy loss. The study finds that greater aspect ratios promote power-to-weight ratio, while high voltage promotes energy efficiency. The paper also discusses the choice of fixed versus variable displacement HMs, with the finding that a variable displacement unit helps address low efficiency limits of low-speed operation, particularly for low voltage electric machines. Additionally, variable displacement can also be used to reduce EM losses when meeting a flow-pressure demand. The proposed methodology has applications in fields such as off-road vehicles.

Common-mode inductors are generally designed so that their operation is in the magnetically linear region of the core material. Very few works consider magnetic hysteresis in the core in terms of the common-mode current waveform. This work validates one such magnetic model and enhances it by including the common-mode current due to the inductor's parasitic capacitance. This work establishes the considerable impact of hysteresis and parasitic capacitance on the ability of a common-mode inductor to reduce the common-mode current. (Statement A: Approved for Release. Distribution is unlimited #2022-0227)

The design of a dc distribution system is posed as an optimization problem, which simultaneously utilizes time-domain analysis, distortion analysis, and stability analysis. The complete power distribution system is taken into consideration in the design process, capturing the interaction between various system components. Multiobjective optimization of mass and power loss metrics subject to transient performance constraints, distortion constraints (voltage and current ripple constraints), and stability constraints is carried out in the proposed design paradigm. This provides an organized framework for the design of dc power distribution systems. The approach is demonstrated through the design of a representative system that consists of a generation system, two isolating peak current controlled dc–dc converter modules, and two constant power loads. A sample design is chosen and verified using a detailed waveform level simulation.