Hybrid electric transmission for hydraulic fracturing

A hybrid hydraulic fracturing system comprising:

• an internal combustion engine;
• a hydraulic fracturing pump;
• a transmission assembly having a first driveshaft, a second driveshaft with at least one of the first or second driveshafts extending along a transmission primary axis, a primary drivetrain gear assembly having at least three gear ratios, the primary drivetrain gear assembly coupling the first driveshaft to the second driveshaft;
• an electric drive gearset separate from the primary drivetrain gear assembly and mounted on one of the first driveshaft or the second driveshaft apart from the primary drivetrain gear assembly;
• and a transmission housing having a first end and a second end and enclosing the primary drivetrain gear assembly, with the first driveshaft extending from the first end of the housing and operatively coupled to the internal combustion engine, and the second driveshaft extending from the second end of the housing and operatively coupled to the hydraulic fracturing pump;
• and
• a plurality of electric motors disposed externally of the transmission housing, each of the plurality of electric motors having an output gearset disposed along an electric motor axis with each output gearset couplable to the electric drive gearset, wherein the electric motor axis of each of the plurality of electric motors is parallel with but spaced radially outward from the transmission primary axis and the transmission housing, and wherein each output gearset is separate from the primary drivetrain gear assembly.