ELECTRICAL HYBRIDIZATION OF HYDROMECHANICAL VARIABLE TRANSMISSION

Methods and systems for a hybrid hydromechanical variable transmission (HVT) are provided. In one example, a transmission system includes a hydraulic pump rotationally coupled to an input shaft; a hydraulic motor rotationally coupled to an output shaft via a first drive range clutch; a planetary gear set including a sun gear rotationally coupled to the hydraulic motor, a carrier rotationally coupled to the output shaft, and a ring gear rotationally coupled to one or more clutches connected to the input shaft; a prime power source rotationally coupled to the input shaft; and an electric machine that is selectively rotationally coupled to the input shaft or to the output shaft, or is mechanically isolated from the input shaft and the output shaft, via actuation of a dog clutch.