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1. Which of the following is NOT the major motivation and benefit of AC modeling of switched mode power supply? (3 pts) a. Predict low-frequency (

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1. Which of the following is NOT the major motivation and benefit of AC modeling of switched mode power supply? (3 pts)
a. Predict low-frequency (. Controller design including feedback loop
c. Analyze input and output cu
ent switching harmonics
d. Analyze output voltage in response to the input voltage pertu
ation
2. Which of the following is TRUE regarding the above power conversion circuit? (3 pts)
a. Transfer function has left half plane zero
. The converter exhibits phase reversal at high frequency
c. Transfer function has left half plane pole
d. Right half plane zero can be eliminated by adjusting filter inductance
    
3. Which of the following statements is TRUE regarding the above power conversion circuit? (3 pts)
a. Transfer function has left half plane zero
. The converter exhibits phase reversal at low frequency
c. Right half plane zero can be eliminated by increasing output capacito
d. Transfer function has two left half plane poles
4. Which of the following statements is FALSE regarding the state-space representation? (3 pts)
a. State-space representation is useful when a system becomes complicated and there are multiple differential equations
. In power electronics circuits, the state vector is generally composed of inductor cu
ent and capacitor voltage
c. Eigenvalues of the state matrix are the poles of the system determining the stability of the converte
d. Eigenvalues of the state matrix are the zeros of the system determining the stability of the converte
5. Which of the following statements is FALSE regarding the solar PV panels and system? (3 pts)
a. Monocrystalline solar panels are generally more efficient than polycrystalline
. Series connected PV cells produces the total cu
ent equal to the sum of all the cu
ent produced by each cell
c. Parallel connected PV cells tend to perform better with shading compared to series connected PV cells
d. Microinverter can solve the partial PV cell shading issue effectively
6. Which of the following statements is TRUE regarding the wind power generation system? (3 pts)
a. The amount of power the wind generator can capture is proportional to the cube of the wind speed
. The amount of power the wind generator can capture is proportional to the square of the blade swept area
c. Controlling the speed of the generator is more important than the pitch and yaw controls in achieving MPP
d. Type 4 wind tu
ine system requires only 50% rated power converters of the electric generato
7. Which of the following statements is FALSE regarding the single-phase passive rectifiers? (3 pts)
a. Two out of four diodes are conducting for 180 degree of the fundamental period
. The peak output dc voltage is equal to the peak of the input AC voltage
c. The input AC cu
ent only flows when the input voltage is higher than the output DC voltage leading to high harmonics
d. The passive rectifier requires additional filter or active power converters to improve the input cu
ent quality
8. Which of the following statements is TRUE regarding the three-phase passive rectifiers? (3 pts)
a. Three out of six diodes are conducting for 60 degree of the fundamental period
. The peak output dc voltage is equal to the peak of the line-to-neutral voltage
c. Each diode needs to be rated to safely block the peak of the DC output voltage
d. Three-phase passive rectifier does not require any additional filter or active power converters to improve the input cu
ent quality
9. Which of the following statements is TRUE regarding the single-phase inverters? (3 pts)
a. There are two active switching states and four zero switching states
. The active switching states can generate both positive and negative peak of the dc-link voltages to the load
c. The single-phase inverter can only provide square wave output cu
ent to the load
d. The single-phase inverter switches do not require anti-parallel diode for four quadrants operation
10. Which of the following statements is FALSE regarding the three-phase inverters? (3 pts)
a. There are six active switching states and two zero switching states
. Three switching devices need to be in on state to create one switching vecto
c. Six-step operation is not used in practical application due to high harmonics in output cu
ent
d. Selective harmonic elimination is prefe
able when the switching frequency is limited to low value
11. A boost converter is used in hy
id electric vehicle for boosting the input battery voltage from 200 V to 800 V. The converter switching frequency is at 10 kHz. (15 pts)
(a) Find state-space representations of boost converter in switch positions 1 and 2 – hint: use capacitor voltage (vc) and inductor cu
ent (iL) as state vector, input voltage is the only input variable, and capacitor voltage is the only output variable). Include the switch conduction loss (Rdson) when the switch is in position 1.
(b) Find the averaged state-space representation of the boost converter.
(c) Redraw the above equivalent small-signal model to find the control-to-output transfer function with the switch conduction loss (Rdson = 5 m) (Vin = 200 V, Vout = 800 V, Iout = 50 A, f = 10 kHz, L = 300 F, C = 2000 F)?
(d) Draw pole and zero location of the above transfer function in the S-plane.
Bonus Question
(e) From the averaged state-space representation in (b), find the denominator of the control-to-output transfer function using det[Is – A]. (I is identity matrix, A is state matrix, det is determinant)
12. A boost converter is used in hy
id electric vehicle for boosting the input battery voltage from 350 V to 800 V. The converter switching frequency is at 20 kHz. (15 pts)

(a) Calculate the switching period (Ts) and duty cycle to keep the output voltage constant at 800 V for the given input voltage.
(b) Calculate the required inductance for achieving 10% inductor peak-to-peak cu
ent to keep the output voltage constant at 800 V for the nominal input voltage of 350 V and the average converter output cu
ent of 50 A assuming the efficiency of the converter is 100%.
(c) Calculate the required capacitance value of the output filter capacitor to ensure at the nominal input voltage of 350 V, the peak-to-peak output voltage ripple is less than 5% of the nominal output voltage (Vout).
(d) Using this specification from (b) and (c), derive the open-loop control-to-output (Gvd) and draw pole and zero location of the above transfer function in the S-plane.
(e) Using this specification from (b) and (c), derive the open-loop line-to-output (Gvg) and draw pole and zero location of the above transfer function in the S-plane.
13. A full-wave three-phase passive rectifier is given below: (20 pts)
    The input AC voltage of 480 V (line-to-line) at 60 Hz is supplied through delta-star transformer with the turn ration of 4:1.
    
(a) Calculate the line-to-line voltage of wye connected transformer (input voltage of the diode rectifier).
(b) Find the average dc-link voltage when there is no filter capacitor.
(c) Calculate the maximum dc-link voltage that this passive rectifier can reach.
(d) Assuming the phase AB, BC, and CA line-to-line voltage waveforms are given below:
    During the period from 210 to 270 degree, which diodes from the rectifier circuit will turn on?
(e) What is the frequency of the major harmonic content in the output dc voltage?
14. A three-phase inverter output voltage is shown below: (20 pts)


(a) Measured three-phase output voltage is shown in the above figure (Vpeak = XXXXXXXXXXV). Looking at the shape of the output voltage, is this line-to-line voltage or line-to-neutral voltage?
(b) What is the dc-link voltage (Vd)?
(c) If the above figure is line-to-neutral voltage, roughly draw line-to-line voltage (with peak voltage and shape). If the above figure is line-to-line voltage, roughly draw line-to-neutral voltage (with peak voltage and shape).
(d) Tesla EV model 3 is fed by 350 V lithium-ion battery. What is the maximum line-to-line voltage the three-phase inverter can produce from 350 V battery? What is the maximum line-to-neutral voltage that the inverter can produce (peak of the fundamental component)?
Answered Same Day Dec 16, 2022

Solution

Baljit answered on Dec 17 2022
31 Votes
1. Which of the following is NOT the major motivation and benefit of AC modeling of switched mode power supply? (3 pts)
a. Predict low-frequency (. Controller design including feedback loop
c. Analyze input and output cu
ent switching harmonics
d. Analyze output voltage in response to the input voltage pertu
ation
2. Which of the following is TRUE regarding the above power conversion circuit? (3 pts)
a. Transfer function has left half plane zero
. The converter exhibits phase reversal at high frequency
c. Transfer function has left half plane pole
d. Right half plane zero can be eliminated by adjusting filter inductance
    
3. Which of the following statements is TRUE regarding the above power conversion circuit? (3 pts)
a. Transfer function has left half plane zero
. The converter exhibits phase reversal at low frequency
c. Right half plane zero can be eliminated by increasing output capacito
d. Transfer function has two left half plane poles
4. Which of the following statements is FALSE regarding the state-space representation? (3 pts)
a. State-space representation is useful when a system becomes complicated and there are multiple differential equations
. In power electronics circuits, the state vector is generally composed of inductor cu
ent and capacitor voltage
c. Eigenvalues of the state matrix are the poles of the system determining the stability of the converte
d. Eigenvalues of the state matrix are the zeros of the system determining the stability of the converte
5. Which of the following statements is FALSE regarding the solar PV panels and system? (3 pts)
a. Monocrystalline solar panels are generally more efficient than polycrystalline
. Series connected PV cells produces the total cu
ent equal to the sum of all the cu
ent produced by each cell
c. Parallel connected PV cells tend to perform better with shading compared to series connected PV cells
d. Micro inverter can solve the partial PV cell shading issue effectively
6. Which of the following statements is TRUE regarding the wind power generation system? (3 pts)
a. The amount of power the wind generator can capture is proportional to the cube of the wind speed
. The amount of power the wind generator can capture is proportional to the square of the blade swept area
c. Controlling the speed of the generator is more important than the pitch and yaw controls in achieving MPP
d. Type 4 wind tu
ine system requires only 50% rated power converters of the electric generato
7. Which of the following statements is...
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