Regarding the present situation of freight elevators among vertical farms to meet the new demand for peculiar functions, an extensible cargo drive system structure was presented with the study object of cargo lift for feedstuff, poultry and garbage transportation in vertical farms. Different from common cargo lift, after elevator door and layer door opening, cargo trolley needed to finish the task of passing in and out of elevator car through coordination running of driving motors in the elevator and outside of layer doors. The dynamic mathematical model for internal and external motors of elevator car was established according to the motor groups driving system. On the basis, trolleys were controlled when they passed in and out. And a vector control method of multimotor along the direction of rotor magnetic field was proposed based on the model identification. The cost of driving system was taken into account and the hardware structure was simplified, the method omitted torque sensor. The multiparameter linear adding weight model was created by integration of torque of three phase asynchronous motor, rotor flux, and estimation of the rotor position in order to obtain feedback quantity. In the final experiment, through the root mean square error, the identified results of torque were very close to the nonlinearity of the reference model. The feedback loop of control system was composed of torque and other multiparameter identification results. The experimental results showed that the control method was effective and advanced.