Research Of Stepless Speed Regulating High-power Motor System Soft-start And Efficiency Based On Planetary Differential Technology

The power consumption of high-power motor accounts for a large proportion inindustrial electric power, which mainly is used to drive the heavy machinery, fan andpump and so on. However, most of them have stepless speed regulating requirement, andthe currently solution is variable frequency technology. Due to the high-power inverter isvery expensive and low efficiency in low-speed segment of variable frequency motor,which lead to have many difficulties to promote and apply for the majority of corporations,and the high energy consumption is wasted. In this paper according to the present situationof high-power motor, a project of stepless speed regulating high-power motor systembased on planetary differential technology aming to solve the above difficulties isproposed.First of all, based on the precious researches, a project of stepless speed regulatinghigh-power motor system based on planetary differential technology is proposed. Thedynamic and static mechanics of system are analyzed to verify that the system can realizefunctions of stepless speed regulation and soft start in theory; in addition, the power oftwo motor’s shafts of system are analyzed by mathematical method in order to study howto match their powers.Then, in this thesis the constant torque load and quadratic rate load as the engineeringbackground, the soft start of system is analyzed and the equation of soft start is established,and the condition of soft start is solved by using Matlab software. Using Matlab/Simulinksoftware established two kinds of simulation models of direct start and soft start of system,then starting current situation of high-power motor is analyzed under two kinds of startingmodels.Secondly, the internal power flows of system are studied and the working conditionsof the frequency control of motor undergoing the forward and reversion of speed areanalyzed, and the efficiency fitting formula of power generation of motor is obtained. Theefficiency of system is studied by the mathematical definition of efficiency. By usingMatlab software, the efficiency formula of system is visually analyzed. Combined with the cost of system, the system will have a comprehensive evaluation.Finally, through the theoretical analysis of energy consumption for an engineeringexample respectively applied this system and the variable frequency technology, theeconomic benefits of both are compared.