Hydrostatic transmission has been paid much attention in renewable energy exploitation including wind energy and wave energy. In a wind power system with hydrostatic transmission,the generation device which is just the hydrostatic-driven electric generator can be separated from the wind turbine and installed at the ground level. Therefore, the system requires lessmaintenance and cost and makes installation more convenient in comparison with the conventional gearbox transmission system [13], [14]. In addition, design and manufacturing difficulties can be further alleviated by using hybrid transmission technology [15]. As to wave energy generation, the kinetic
energy generated by the translational movements of irregular
waves can be absorbed and converted to hydrostatic energy by
using a hydrostatic energy converter with an oscillating buoyant
body [16]–[19]. Then, the hydrostatic-driven electric generator
is used to realize electricity generation, which is similar to the
wind power system.