说明：  INDUCTION MOTOR RUN (Currents and speed as state variables) The motor is running at a specified load. After reaching steady state in an initialization first run, the initial conditions are established for a second run in which the load is pulsating. The dynamic equations are expressed in canonical first-order matrix form adopting currents and speed as state variables, and are solved using ODE45. The user has the choice of selecting one of three common (dq) reference frames: STATOR, ROTOR or SYNCHRONOUS. The torque, speed,and current responses are plotted.