It should be noticed that the hydrostatic-driven electric generators aforementioned are mostly composed of independent hydrostatic motors and coaxially coupled generators. This configuration usually has large volume and is prone to suffering difficulties when there is limited space such as mobile machinery and vehicles. Therefore, it is necessary to develop more compact components. There have been several literatures about integrated energy conversion devices between hydrostatic energy and electrical energy. The shaft of a permanent magnet electric machine is directly operated on the shaft of a hydrostatic pump/motor so that a coupling is eliminated, and losses analysis and efficiency measurements are also presented in detail [20], [21]. The literature [22] studies a compact machine where an induction motor and a vane pump are integrated together,