Research on the application of PFC technology in cascade speed control system

Poor line power factor is one of disadvantages of the cascade speed control in wound rotor induction motor drives. So a new method to improve the line power factor of cascade speed control system is proposed, which integrates power factor correction (PFC) and cascade speed control. Then the principle of cascade speed control (CSC) with PFC is analyzed in detail. For the low slip voltage frequency, a novel three-phase PFC is realized with the symmetrical balanced Scott transformer and single phase active PFC. Specific considerations and calculations of parameters of the single phase active PFC used in CSC are discussed. Simulation model of cascade speed control with PFC is established with MATLAB/SIMULINK. Results of simulation show that the new speed control method has advantages of both CSC and rotor resistance speed control. Furthermore, system efficiency and line power factor are improved.