Electrical Paper

In this activity, you will write the third part of your term paper.

Explain why we need a rectifier and a forward converter to make a DC power supply.


Please go through the given instructions and write a paper on switch-mode DC power supplies. Please see detailed instructions for requirements from the term paper document below. Use illustrations if necessary.


Your paper needs to answer the following questions along with your comments and discussion.

In this part of the term paper, design a single-phase switch-mode DC power supply with a forward converter. Provide answers to the questions below.

Please combine the single-phase full-wave rectifier from part two of your term paper with a forward converter to produce a switch-mode DC power supply, as shown below. The output of the bridge rectifier serves as input to the forward converter.

As explained, a forward converter is a popular switched mode power supply (SMPS) circuit that is used for producing isolated and controlled DC voltage from the unregulated DC input supply. It consists of a fast switching device ‘S’ along with its control circuitry, a transformer with its primary winding connected in series with switch ‘S’ to the input supply, and a rectification and filtering circuit for the transformer secondary winding. The load is connected across the rectified output of the transformer secondary. It is basically a DC-DC buck converter (as seen in part one of the term paper) with the addition of a transformer for output voltage isolation and scaling. When switch ‘S’ is turned on, input DC gets applied to the primary winding and simultaneously a scaled voltage appears across the transformer secondary. When switch ‘S’ is turned off, the primary as well as the secondary winding currents are suddenly brought down to zero. Current through the filter inductor and the load continues without any abrupt change. Diode ‘D2’ provides the freewheeling path for this current. The DC output is similar to that of a buck converter multiplied by the transformer winding ratio:

  

Assume all ideal components including the isolating transformer,    and switch frequency is 16.7 kHz as in part one of the term paper. Design this switch-mode DC power supply by doing the following:

·         Determine the duty ratio D so that the DC output to the load is 12 v. Draw the waveform of the input AC voltage V1, bridge rectifier output (see part two of the term paper; this is also the input to the forward converter), voltage after diode D1, and voltage at the load (with all harmonics blocked).

·         Explain why a transformer still works even with a DC input to the forward converter.

·         Explain the function of diode D1.

Please include all necessary circuit diagrams or block diagrams in your paper. Please also draw the necessary waveforms together with your comments or discussion.

Your paper should be at least two pages, typed single-spaced, using 12-point font and 1-inch margins on the top, bottom, right, and left. You should use the APA guidelines for writing and citations.

Keep the following points in mind:

·         The efficiency of a buck DC-DC converter.

·         The principle of a buck DC-DC converter.

 

 

Physics: Application of Newton’s Laws

The following questions ask you to solve problems involving Newton’s laws and forces

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Work out each problem and post an image of your work for each question along with a brief description of how you solved the problem.

 

Your scanned work should include a free body diagram showing all forces acting on the object(s), as well as a step-by-step solution to the problem.

 

Question 1

A 2 kg book resting on a flat table requires an applied force of 4 N to make it move. Draw a free body diagram illustrating this situation and find the coefficient of static friction between the book and the table.

 

Question 2

A 30 kg crate is pulled across a flat floor with 80 N of force. The coefficient of kinetic friction between the crate and the floor is 0.15. Draw a free body diagram illustrating this situation and find the acceleration of the crate.

 

Question 3

An applied force of 100 N causes a 20 kg crate to accelerate across a level floor at 2 m/s2. Draw a free body diagram illustrating this situation and find the coefficient of kinetic friction between the crate and the floor.

 

Question 4

60 N of force is applied to a 10 kg crate initially at rest on a level floor. The coefficient of friction between the crate and the floor is 0.4. Draw a free body diagram illustrating this situation and find the distance traveled and the velocity of the crate after 3 seconds.

 

 

Question 5

Sue and Bill are standing on a frictionless surface of ice. Sue, whose mass is 60 kg, pushes Bill, mass 100 kg, with 300 N of force. Draw a free body diagram illustrating this situation and find the acceleration of both Sue and Bill.

Design Project Assignment

Description:

The hottest band in the town of Sparkyville is “Maroon (and Gold) 4”.  They are known for their musical experimentation and unique instruments.  They plan to go on tour and would like to minimize the space required for their musical instruments.  Your company has been hired by Maroon (and Gold) 4 to design the instruments for their new tour. Your team must design 3 instruments (one for each part in the song) capable of playing at least one of their hit songs, “Ode to Joy”. Please note that a complete “design” is one that consists of the entire set of all 3 instruments. Each of the three types of instruments (wind, percussion, and string) must be represented in your design and they must be designed in such a way that they will all (i.e., your design) fit into ONE 2 ft x 2 ft x 2 ft stage box. Your design should cost as little as possible and be aesthetically pleasing and creativity is encouraged.  You will be required to demonstrate your design by playing one of their hit songs and combining (and possibly editing) audio files to create a cover track of the song so that they will know how it will sound before going on tour.  You will also be required to document and demonstrate each individual instrument as a part of the project.

Project Specifications:

 There should be one instrument per part in the musical scores.  One instrument in the design needs to be a wind instrument, at least one needs to be a percussion instrument (bar based percussion instrument), and at least one needs to be a string instrument. Physical principles and mathematical calculations (will be introduced in the Acoustics unit) should be used to guide your design decisions. Please note that drums are membrane based percussion instruments, which are beyond the scope of this course, thus, the physics behind drums will NOT be introduced. You must build your own instrument.  Using websites that contain instructions on how to build a specific instrument may be used to get ideas for your design; however, such sources MUST be cited and may lower the “creativity” of your design.  You must make sure that your designs do indeed meet the requirements of this particular project.

 You are required to create a track (song with all instruments playing their different parts) of the song mentioned in the Description.  Sheet music, a listing of the notes, and the individual parts will be provided for your reference. You may use the free program, Audacity (http://audacity.sourceforge.net/), to record, edit, process, export, play, and combine audio files.   

Resource Limitations:

your design should have 3 instruments, and you must be able to prove that your design (with all 4 instruments) will fit within the 2 ft x 2ft x 2ft stage box.  This will most likely be done with a sketch and packing instructions.  You cannot use any more than 10 ft of pipe (of any diameter or material) and 6 ft of strings (of any gauge or material) in the set of instruments. Even if the material is not being used for sound creation, it still must be considered in these constraints (for instance, if you are using PVC pipe for the structure of your string instrument, you must include that length in the pipe constraint). 

Your design should have 3 instruments and one of the 3 instruments will have to play two parts and this instrument will have to be duplicated such that all above mentioned limitations are applied to a total of 3 instruments (you are not required to build the duplicated instrument, just count it twice). Thus, you must prove that all these 3 instruments will fit within the 2ft x 2ft x 2ft box. This will most likely be done with a sketch and packing instructions. You cannot use any more than 10 ft of pipe (of any diameter or material) and 6 ft of strings (of any gauge or material) in the set of these 4 instruments.

Budget & Supplies:

You are required to track all expenses related to the construction of your instrument for inclusion in a budget.  Each instrument cannot have spending more than $15 and every material used (even if pulled from the trash) must have a value associated with it and be included in the budget.  Discuss value of recycled items with instructor before using them in your design.  Only materials used in the design need to be included in budget (for instance, if you buy 20 nails and only use 5 in your design take the total cost divided by 5 for the amount that will be in your budget).  Adhesives and tapes do not need to be included in budget unless the cost of the tapes/adhesives is the pre dominate expense of the design (if your entire instrument is made of duct tape, than you should take that into account).   There is a flat $1 painting fee, regardless of the amount of paint used.

 

Project Deliverable: Problem Definition 

It is very important that you understand the design problem you are solving, the requirements/constraints and your objectives. Defining the problem is often the most important step in a design process. For this project deliverable, you will identify all the requirements/constraints of this design project; identify your objectives; write up a problem definition statement; and create a prioritized list of criteria for success.  

Project Requirements and Problem Definition   

Carefully read the project document. Pay attention to the requirements of this project. List all the design requirements and constraints in bullet points. Identify the goals/objectives of this design project; and compare and combine your lists of requirements. When you consider and discuss the constraints, also think about the construction tools (e.g., hand saw, drills, etc.) and construction materials that are available to you. Then discuss and write down a problem definition statement of this design project. The problem definition statement should clearly identify the underlying problem that needs to be solved and summarize the important constraints. Be as specific as possible but try to avoid statements that lead to a particular solution. Create a list of all the project requirements.  Be specific and quantitative. Discuss and list criteria for a good design and prioritize the criteria.  You should also generate three different instrument ideas for “high”, “medium”, and “low” range (so 9 instrument ideas total).  Each of these designs should be viable, unique solutions to the problem (solve the problem, meet all of the design requirements, etc.).  For each conceptual design you should describe the form, function (a description of how it works), and finish (what materials…as best as possible at this point).  

Deliverables: 

Follow the format described below.   

• Your deliverable should be typed (single spaced) in paragraph form, with appropriately formatted section headings (use bold and/or underline, and/or larger font size). You should use consistent spacing, formatting, font, and style, as well as correct grammar and spelling. 

• A title ‘Problem Definition’ should be included at the top. 

Make sure to include the following in your document: 

• All requirements and constraints in bullet points

• Problem definition statement 

• Prioritized criteria with assigned weights

 • Description of your 9 instrument ideas

o  3 for “high” range

 o  3 for “medium” range

o  3 for “low” range

 

Project Deliverable: Project Schedule  

Completing a design project takes planning. As a part of the project you will be completing, you will need to create a plan to meet all of the project deliverables. During the project, many considerations will be taken into account, including budget concerns, size constraints, and building materials (among others). For this project deliverable, your must create a project schedule (Gantt Chart).   

Identifying Tasks:  

Identify all the tasks you will have for the project. Please be as specific as possible. You will need to consider the dependence of a task on another and consider tasks that may run simultaneously. Estimate time it may take your to complete each task. Make sure that all deadlines are met.

Creating a Gantt Chart:

You may create a Gantt chart in Excel, MS Project (this creates nice looking Gantt Charts). In a Gantt chart, tasks are listed in the left column (one task per row), and dates run along the top in increments of days, weeks, or months depending on the total length of the project. The expected duration of each task is represented by a horizontal colored bar, with the left end at the expected start date for that task, and the right end at the expected completion date. Some tasks may run simultaneously (in parallel), some may overlap in time, and some may occur sequentially (one task ends, then another starts).  If a task is dependent on another task, the two tasks are connected with an arrow to indicate that one cannot start until the other ends. For example, if Task A is to purchase materials, and Task C is to construct a component, Task C is dependent on Task A because you cannot construct a component until after you have purchased the necessary materials. 

It is often a good idea to include milestones or other events on your Gantt chart that indicate your progress but are not tasks. For example, you may want to include when the final prototype will be complete, when certain project deliverables are due, etc. These ‘milestone’ events are entered as a symbol (often a triangle or diamond) on a single date on the Gantt chart. 

Using your Gantt Chart:

 

You should check your Gantt chart regularly to identify what tasks need to be completed, and to ensure that you stays on track to successfully complete the project on time.  As you proceed through the design process, you may identify more specific tasks that should be added to your project schedule. The project schedule can be continually updated—when you identify additional tasks that need to be completed, you should add them.  The more detailed you can be early on in making your schedule, the easier it will be to complete the project on time (for instance, “Build prototype” is not as useful of a task as  “Build base,” “Cut holes,” etc.).  A revised project schedule will be due before you begin construction of your prototype (as a part of your proposal document), so the more detail you are able to add now, the less you will have to change later.     

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You have just started a bungy Jump business called Go Jump. A jump platform has been built that is 50 m above a river bend where the depth of the river is 4 m. The grand opening will be in two weeks’ time. As part of the grand opening, you are also demonstrating, for the first time, a new type of bungy cord made from an innovative ultra light material. The grand opening will be attended by the Victorian Minister for Tourism and Major Events to promote exciting tourism businesses and innovations in technology. The media will be a plenty.

As a precaution, you have decided that you will be first jumper to test the platform. You want to ensure that maximum wow factor is achieved by setting the jump such that you touch the water. Unfortunately, the new cord has not yet been tested and has no specs. How should you set up your jump to ensure that everything goes smoothly with no accidents or incidents with the first jump during the grand opening?

 

Learning Objectives:

After completion of this problem, students should be able to:

  1. Understand the concept of oscillatory motion.
  2. Understand elastic forces and elastic potential energy.
  3. Analyse a spring-mass system moving in vertical motion.

 

Learning Resources:

  • Lecture notes on Momentum
  • Chapters 15 of e-text book: “Fundamentals of Physics” 10th Edition, Halliday & Resnick.
  • Videos on VU Collaborate

 https://www.youtube.com/watch?v=DVtyRt0CSSw

Students must work in teams of 2 – 4 students

(This is to reinforce collaborative and peer learning, individual submissions will not be accepted)

 

Solutions Submission

Your submission needs to:

  • reference the source of any information that you use in your solution.
  • justify solutions with appropriate comments.
  • describe the physics involved to demonstrate that you understood the physics and achieved the learning objectives. No evidence of understanding of physics will not receive any marks.
  • Be typed or written in clearly and neatly.

On your submission,

  • clearly state the full names and IDs of the team members.
  • Indicate which tutorial group you belong to. 
  • include the Problem Identification worksheet.

This problem is worth 2 marks.

 
IMPORANT NOTICE

Additional spplementary information about this problem is required to solve this problem. This supplementary information will be only be released to groups who have completed the first 2 steps in the Defining Learning Issues worksheet. If you did not receive the supplementary materials in the first class, email your team’s Defining Learning Issues worksheet with steps 1 and 2 completed to the lecturer to receive the supplementary material.