EE 4420: Homework #4 Name ……………………….Due day: 10.25.20041.A 100 hp, 600 V, 1800 rpm, separately excited DC motor is supplied by a switch-mode PWM converter. The motor parameters are: Ra= 0.1 Ω, La= 5 mH, KE= KT= 2.86 V/(rad/s), J = 1.5ּ10-3kgּm2, B = 0.02 Nּm/(rad/s). The converter parameters are: Vd= 600 V, Vtri= 5 V., fs= 33 kHz.1)Design the current control loop with the unity feedback. Assume phase margin ΦPM,I= 90o, and the crossover frequency fcI= 1 kHz. Find the PI controller gain kp,Iand ki,Iignoring back EMF Ealoop.2)Design the speed control loop with the unity feedback. Assume phase margin ΦPM,Ω= 60o, and the crossover frequency fcΩ= 100 Hz. Find the PI controller gain kp,Ωand ki,Ωassuming the closed-current loop to be ideal.3)Build the block diagram of the motor with current and speed PI controllers and simulate starting of DC motor assuming the rated reference speed and zero load torque (initial conditions). After the motor reached the steady speed, load the rotor with the rated load torque and record the speed and current.
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