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Advanced Electric Drives: Analysis, Control, and Modeling Using MATLAB / Simulink

23 SOLVED PROBLEMS

Question: 7.2

A DFIG is operating in the generator mode at a supersynchronous speed at a leading power factor (supplying Qs to the grid). Calculate the signs of various quantities in this mode of operation (Fig. 7-5). ...

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\begin{aligned} \omega_{\text {slip }} &am...
Question: 7.1

A DFIG is operating in the motoring mode at a subsynchronous speed at a lagging power factor (drawing Qs from the grid). Calculate the signs of various quantities in this mode of operation. ...

Verified Answer:

\begin{aligned}\omega_{\text {slip }} &...
Question: 6.3

Consider the “test” machine described in Chapter 1 and considered in Example 5-4 of the previous chapter. Now consider that the estimated rotor resistance is incorrect and Rr_est = 1.1Rr. Modify your simulation in Example 5-4 and simulate the system without the compensation terms. Assume that the ...

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Question: 6.1

In an induction motor, with the nameplate data given below, under a blocked-rotor condition, the flux is initially built up to its rated value (with isd(0)=3.1 A). The toque is commanded to change as a step (isq^*=4.0 A) from zero to nearly 50% of its rated value. Plot the dynamics of isd, isq, ...

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Figure 6-4 shows the simulation diagram in Simulin...
Question: 5.1

The motor model developed earlier, with the d-axis aligned with λr, can be used to model induction machines where vector control is not the objective. To illustrate this, we will repeat the simulation of Example 3-3 of a line-fed motor using this new motor model (which is much simpler) and compare ...

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We need to recalculate initial flux values because...
Question: 5.4

Consider the “test” machine described in Chapter 1. This machine is operating in steady state under its rated conditions, supplying its rated torque. At t = 1 second, the load torque suddenly goes to onehalf of its initial value and stays there. The objective is to maintain the speed of this ...

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Question: 5.3

Repeat the vector control of Example 5-2 by replacing the CR-PWM inverter by a space vector pulse width-modulated inverter, which is assumed to be ideal. The speed loop specifications are the same as in Example 5-2. The current (torque) loop to generate reference voltage has 10 times the bandwidth ...

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Calculations for the initial conditions are repeat...
Question: 3.7

The machine in Example 3-5 is made to go into the generator mode. Make the load torque change linearly from its initial rated positive value to the rated negative value in 0.2 seconds. Plot various quantities as a function of time. ...

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Question: 3.6

Use the initial conditions calculated in Example 3-5 to simulate a sudden change in load torque to one-half of its initial value. Plot various quantities as a function of time. ...

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Question: 3.5

Consider the “test” machine described in Chapter 1. Assume that this machine is operating under its rated condition in steady state, supplying its rated torque. Calculate the initial values of the flux linkages of dq windings, the dq currents, the rotor speed, and the torque for the following three ...

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