EE4161
Homework Assignment
Due April 30
100%
40%
I (A)
1. A 30 Ah battery has the following IV profile. Assume it is at a particular SOC (state of
charge) and is charged for a very short time at 0.1C. It is then discharged at 0.1C for the
same amount of t
EE4161
Homework Assignment
Due Feb 26
I (mA)
1. Three solar cells are connected in series with individual shunt diodes. The short circuit currents are 20, 10, and 2 mA. On the plot below, the IV characteristic of each diode and shunt
is shown separately.
Admin
Overview
Course Focus
1. Photovoltaic devices are being developed as an
important energy source. Though under development
for over 35 years, they still need improvement to be
economical. They are close. We will discuss the
physics of their operation
EE4161
Homework Assignment
Due April 30
A battery is discharged from 100% SOC at a rate of C/2 for 30 minutes. How long will it
take to fully recharge the battery at a rate of C/10? Assume that the battery follows the Peukert
equation with k=1.3, i.e.
ik
Homework_April_30
1 of 2
http:/127.0.0.1:8888/589d852e-6f15-4a2b-ad76-73ad29402618
In [17]: from _future_ import division
Prob 1
At each SOC the battery is charged and discharged for equal times. The energy required to charge is
trip efficiency is
=
Q V =
EE4161
Homework Assignment
Due Thurs, April 11
1. 1 mol of H2 SO4 completely dissociates into H+ and HSO4 in 1 liter of water. What is the
hydrogen ion concentration per cc?
2. For the nanowire battery electrode shown, estimate the effective surface area
Homework problems
Q1
In the power converter diagrammed below, plot ia from zero to 80 sec for three cases.
a) Pout = 50 W, steady state
b) Pout = 12.8 W, steady state
c) Pout = 8 W, steady state
How would this change if the switch was comprised of an uppe
Homework 1
1 of 3
http:/127.0.0.1:8888/4b46215f-416a-41cd-8deb-2f267ac33954
Solutions to homework set #1:
This uses python notebook software. It is like Matlab, free, and runs on platforms other than windows. I am using version 2.7. It is a package based
EE 4161 Spring 2013 HW6 Solutions
Q1
For the Buck converter shown below
minVin = 50 VDC
maxVin = 200 VDC
VO = 40 VDC
RL = 5 ohms
Vcr = 0.7 V
Rd,on = 0.1 ohms (FET equivalent resistance when on)
For the range of input voltages given above, plot the followi
Hmwk3
1 of 3
http:/127.0.0.1:8888/4281f8d9-6a92-4f22-93ca-6a1b41.
In [76]: from _future_ import division #python quirk
from IPython.core.display import Image
Prob 4:
It is easiest to do this in spice. There will be a voltage across and current through the
http:/www.currentresults.com/Weather/Minnesota/average-sunshinejanuary.php
From the data through the website that I gave, we can get this:
Month
Jan
Feb
Mar
Apr
May
Jun
July
Aug
Sep
Oct
Nov
Dec
Total days
with sun
15
15
14
15
16
17
22
21
18
17
11
12
From
2013-04-08
1 of 3
http:/127.0.0.1:8888/43cf2f3a-e260-4344-9fc8-6f3671bc635d
In [56]: from _future_ import division
#a python idiosyncracy;ignore
1) 1 mol of ions in a liter is an Avogadro number divided by 1000 cm3 to get the density in cm3
In [57]: NA=6.
EE4161
White Paper Guidelines
Due Feb 18
The main writing assignment for EE4161W is to be a proposal to a company to invest in a
new technology related to energy that (1) has a strong relation to electrical engineering, (2) you
are able to describe in tec
EE4161
Homework Assignment
Due Thurs, April 11
1. 1 mol of H2 SO4 completely dissociates into H+ and HSO4 in 1 liter of water. What is the
hydrogen ion concentration per cc?
2. For the nanowire battery electrode shown, estimate the effective surface area
EE4161
Homework Assignment
Due Jan 31
1. Download the solar spectrum for AM1.5 (google AM1.5 and xls). Plot the number of photons
per unit wavelength per second striking the earth per square meter vs wavelength. Use the
direct + circumsolar data.
2. From
EE4161
Homework Assignment
Due Thurs, Apr 4
.
Homework
problems
Q1
In the power converter diagrammed below, plot ia from zero to 80 sec for three cases.
a) Pout = 50 W, steady state
b) Pout = 12.8 W, steady state
c) Pout = 8 W, steady state
How w
EE4161
Homework Assignment
Due Mar12
Q1 .
For the Buck converter shown below
minVin = 50 VDC
maxVin = 200 VDC
VO = 40 VDC
RL = 5 ohms
Vcr = 0.7 V
Rd,on = 0.1 ohms (FET equivalent resistance when on)
For the range of input voltages given above, plot the fo
Hmwk4
1 of 2
http:/127.0.0.1:8888/4a261f17-e3ba-4f05-ac4e-1bb59dbe6142
In [40]: from _future_ import division
#python quirk
Prob 3
The figure is from Sunpower. The goal here is to understand the properties of their cells.
Since the short circuit current i
EE4161
Homework Assignment
Due Feb 19
1. Read Sec. 4 in PVCDROM at http:/pveducation.org/pvcdrom .
2. A 1400 word white paper is due on Monday, Feb 18. Detailed instructions are posted on
Moodle.
3. Sunpowers website shows the following data for one of it
EE4161
Homework Assignment
Due Feb 12
1. In the power system shown below, all lines are 1000 ohms, purely inductive. A generator at
V1 is supplying 250 kW of real power. Calculate the angles between the voltage busses,
Fig. 1: Grid problem 1
12 , 13 , 23
EE4161Exam 2 Spring 2013
Solutions
1. 3 mistakes in boost converter
Diode needs to be flipped back-to-front so current can actually flow
Capacitor at Output has the wrong polarity, flip this also.
Transistor control switch doesnt function as drawn. The NP
EE4161
Homework Assignment
Due Feb 5
1. A solar cell has a short circuit current density of 30 mA/cm2 and an open circuit voltage
of 0.60 V under one-sun illumination at room temperature. Use the ideal diode equation to
calculate the open circuit voltage
EE4161
Homework Assignment
Due Tues, May 7
1. The force on a vehicle on level ground is
m
dv
1
= Fapplied Crr FN ACd v2 .
dt
2
Here the coefficient of rolling resistance Crr = 0.013, FN is the normal force (down), Cd = 0.4
is the drag coefficient, = 1.3 k
EE4161 - Homework # 2 Solutions
1. Use the ideal diode equation to calculate the open circuit voltage which is expected
at 1000 suns.
iD = Io (eVD /VT 1) Isc
Rearrange under open circuit conditions:
iD = 0, Isc = 0.030 A/cm2 , VD = 0.6 V, VT = 0.0259 V.
I
Homework Due May 7
1 of 4
http:/127.0.0.1:8888/90737391-b9b9-4d4e-8398-834b0c5bbedd
Set due May 1, 2012:
The following uses python, which is very close in syntax to Matlab but is free, provides easier use of functions, and has a
"notebook" mode that works