Consider a permanent magnet dc servo motor with the following parameters:
Tem(rated) = 10Nm
Rated Speed in rpm Nrpm = 3700
kT = 0.5Nm/A
kE = 0.5V/rad/s
Ra = 0.37Ω
La/Ra = 4.05 × 10−3 s
Jeq = 0.0079kg-m2
The servo motor is driven by a full-bridge four-quadrant dc-dc converter operating from a 200V dc bus. The motor is delivering a torque of 5Nm at a speed of 1500rpm. The switching frequency is 20kHz.
1. Build the above dc motor and power electronic converter in Simulink.
Using the simulation model, determine the peak-peak ripple in the armature current for the above operating condition in open-loop?
2. Design the current loop for a crossover frequency of 1kHz and the speed controller for a crossover frequency of 100Hz.
3. Build the closed loop model in Simulink. In the model, For a step increase in load torque from 5Nm to 10Nm, with the speed reference at rated value, plot the response of the system speed and armature current.