Doubly-fed induction machine differential cascade. II. Verification by test

In this paper, the doubly-fed differential cascade (DFDC) analysis, in the steady state, given in Part I, is verified by tests. The DFDC consists of two similar doubly-fed machines having the corresponding phases of the two rotors connected. Two sources are used to supply the DFDC stators. One is the mains and the other is a variable frequency converter. The DFDC is loaded with two DC machines acting as brakes. Operations similar to the ones required to provide propulsion to a vehicle are simulated. Variable speed and direction, when the vehicle is moving on a straight course, is simulated by varying the frequency of the frequency converter. Vehicle turn is simulated by distributing the load on the two machines. A nonmoving vehicle, held on a ramp by the DFDC developed torque, is simulated by applying the same frequency to both machines. The experimental results are compared with the results from the analysis.