Dual path electromechanical transmission for off-highway vehicles

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Hydraulic motors have been used in off-highway vehicle transmission systems. Recently, many industrial manufacturers have adopted electrical motors to provide propulsion for off-highway vehicles such as excavation machines and dozers. In this work, a comprehensive comparison is presented on the differences between a hydraulic motor and a permanent magnet synchronous motor (PMSM). An efficiency map, moment of inertia, and energy consumption, as well as dynamic behavior are used to present specific information about the two motors. Efficiency maps indicate that PMSMs are more efficient than hydraulic motors. The moment of inertia study gives an idea about the size difference between the two motors where it shows that the hydraulic motor is much smaller than the PMSM, even though they both have the same output torque. A load analysis was conducted to determine the dynamic behavior of the two motors, measuring each motor's response to the test loads and how much energy each motor consumes. This dissertation presents a new transmission system design by replacing all hydraulic components in a dual path hydrostatic transmission with electric components. The hydraulic motors are replaced with the PMSMs, and two pumps are replaced with one generator. Since all the components are now electric, the new design is called a dual path electromechanical transmission. The results showed that the new design with electromechanical can do the same task with less energy consumption and higher efficiency.