Consider a permanent-magnet dc-motor with the following parameters: Ra=0.35Ohms, La=1.5mH, Ke=0.5V/(rad/s), Kt=0.5Nm/A, and Jm=0.02kgm^2. The rated torque is 4Nm. This motor is supplies by a switch-mode dc-dc converter that has a dc-bus voltage of 200V. The switching frequency fs=25kHz. Calculate and plot the waveforms for va(t), ea, ia(t), and id(t) under the following conditions:
(a) Motoring in forward direction at 1,500rpm, supplying a load of 3Nm.
(b) Regenertive braking from conditions in (a), with a current of 10A.
(c) Motoring in reverse direction at 1,500rpm, supplying a load of 3Nm.
(d) Regenerative braking from conditions in (c), with a current of 10A.