(Solved): Please answer and explain Q4b) DC-DC Converter Machine Drive Consider the circuit diagram of the DC- ...
Please answer and explain Q4b)
DC-DC Converter Machine Drive Consider the circuit diagram of the DC-DC converter and separately excited DC machine in Figure 1. The parameters of this drive system are as follows: Vs=220VRA=2.45ΩLA=5mHKm=1.25V/rad/sfs=5kHz The converter can be considered as lossless. Take further the brush voltages as zero in the calculations. Figure 1: Circuit diagram of DC-DC converter and DC motor. 1. Calculate the highest shaft speed that can be obtained with this DC machine drive. 2. With a duty cycle of D=0.75 and armature current of IA=5A calculate the speeds of the DC motor drive with two-quadrant and four-quadrant switching. 3. Calculate the supply powers of the converter to the DC machine for the operating condition of (2) with two-quadrant and with four-quadrant switching. 4. With Q3 permanently switched off and Q4 permanently switched on answer the following questions: (a) With the DC-machine operating in steady state at 800r/min and the armature current equals to IA= -10 A (current flowing out at terminal A1 ), determine the switching duty cycle D at which the converter is switched. (b) For the condition of (a) determine the ripple in the armature current ΔiA. (c) For the condition of (a) draw the waveforms of the armature voltage, vA1−A2, and the armature current iA reasonable on scale on one graph.