(Solved): Please answer and explain Q4b) DC-DC Converter Machine Drive Consider the circuit diagram of the DC- ...

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: $V_{\mathrm{s}}=220\mathrm{V}{R}_{\mathrm{A}}=2.45\Omega L_{\mathrm{A}}=5\mathrm{mH}{K}_{\mathrm{m}}=1.25\mathrm{V}/\mathrm{rad}/\mathrm{s}{f}_{\mathrm{s}}=5\mathrm{kHz}$ 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 $I_A=5\mathrm{A}$ 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 $Q_3$ permanently switched off and $Q_4$ permanently switched on answer the following questions: (a) With the DC-machine operating in steady state at $800\mathrm{r}/\min$ and the armature current equals to $I_{\mathrm{A}}=$ -10 A (current flowing out at terminal $A_1$ ), 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 $\Delta i_{\mathrm{A}}$. (c) For the condition of (a) draw the waveforms of the armature voltage, $v_{\mathrm{A}1-\mathrm{A}2}$, and the armature current $i_{\mathrm{A}}$ reasonable on scale on one graph.