Welcome This is a template to create an Instructional Design Document of the concept you have selected for creating animation. This will take you through a 5 section process to provide the necessary details to the animator before starting the animation. The legend on the left will indicate the current status of the document. The Black coloured number will denote the current section, the Turquoise color would denote the completed sections, and the Sky blue color would denote the remaining sections. The slides having 'Instructions' would have a Yellow box, as shown on the top of this slide

Write the Title of the concept here Add Instructor/Instructors name here Switched Mode Power Supplies Prof. Vivek Agarwal

Definitions and Keywords Add the keywords with definitions which are used in this concept Add more slides if required Duty cycle/ratio- The fraction of time for which the switch is ‘ON’ in one complete switching cycle DCM (Discontinuous Conduction Mode)- The operating mode of the converter when the current through the inductor is discontinuous with respect to time i.e. it is zero for some finite duration in a switching cycle. CCM (Continuous Conduction Mode)- The operating mode of the converter when the current through the inductor is continuous with respect to time i.e. it is never zero during the switching cycle. Critical Conduction Mode- The operating mode of the converter when the current through the inductor is just continuous (or just discontinuous) with respect to time

INSTRUCTIONS SLIDE Concept details: In this section, provide the stepwise detailed explanation of the concept. Please fill in the steps of the explanation of the concepts in the table format available in the slides to follow (see the sample below). Resize the table dimensions as per your requirements

Concept details Circuit diagram of a boost type dc- dc converter The switch ‘S’ should open and close with a time period of 0.5 sec 2 Operation of the circuit when the switch ‘S’ is closed The thickened arrows should continuously move in the direction of the “arrow heads” as shown in both the loops Hence current through the inductor increases. The diode D is reverse biased during this interval and does not conduct The current I L should rise slowly from its initial value (Ip - ) to its final value (Ip + )  current through the inductor decreases 3 Operation of the circuit when the switch ‘S’ is open The current I L should fall slowly from Ip + to Ip - value in the slot T OFF The thickened arrows should continuously move in the direction of the “arrow heads” as shown in both the loops As the switch ‘S’ closes and opens, the inductor stores and releases energy giving a boosted output voltage During this interval the diode ‘D’ is forward biased

Concept details Overall operation of the circuit The output voltage expression: Sequentially show the animation of both modes i.e. when the switch is ‘ON’ and when the switch is ‘OFF’ as in the previous two circuits – i.e. the animation toggles between the two states Average voltage across the inductor during a cycle = 0. Therefore: Case I Effect of duty cycle on the operation of the circuit keeping inductor value constant a) CCM operation b) Critical Conduction Mode of operation 5 where, d lies between 0 and 1. Hence, the output voltage gets boosted up Combination of operation when the switch is ‘ON’ and when the switch is ‘OFF’ as given previously The duty cycle needs to be animated here. Starting with a reasonably high duty cycle (as shown in the figure), the inductor current should rise from the initial value Ip - and reach a peak value Ip + at the end of the ON period then slowly decrease back to Ip - at the end of the OFF period as shown in the figure, thereby resulting in a continuous current mode of operation The duty cycle should then be slowly reduced till a point when the inductor current starts from the initial value of 0, reaches a peak Ip at the end of the ON period and then decreases slowly back to 0 exactly at the end of the OFF period as shown in the figure, thereby resulting in a just continuous (or critical) current mode of operation With the same inductor value, the duty cycle is now reduced such that the current through the inductor becomes just continuous – Critical Conduction Mode For a given inductor value and reasonably large duty cycle, the current through the inductor is continuous (as shown) i.e. CCM operation

Concept details Effect of inductor value on the operation of the circuit keeping duty cycle fixed a) CCM operation With the same (fixed) duty cycle, the inductor value is now reduced till the point when the inductor current becomes just continuous – Critical Conduction Mode b) Critical Conduction Mode of operation c) DCM operation Case II Next, the duty cycle should be further reduced till a point is reached when the inductor current starts from the initial value of 0, reaches a peak Ip + (new) at the end of the ON period and then decreases slowly back to 0 before the end of the OFF period as shown in the figure, thereby resulting in a discontinuous current mode of operation Without changing the inductor value, the duty cycle is further reduced till the inductor current becomes fully discontinuous i.e. DCM operation. Ip +( new) >Ip> Ip+ For a given (fixed) duty cycle and a reasonably large inductor value, the current through the inductor is continuous i.e. CCM operation Here, the inductor size needs to be animated giving the waveforms according to the size of the inductor used in the circuit. Starting with a high value of inductor (shown in the figure with a bigger size), the inductor current should rise from the initial value Ip - and reach a peak value Ip + at the end of the ON period then slowly decrease back to Ip - at the end of the OFF period as shown in the figure, thereby resulting in a continuous current mode of operation The inductor size should be slowly reduced till a point is reached when the inductor current starts from the initial value of 0, reaches a peak Ip at the end of the ON period and then decreases slowly back to 0 exactly at the end of the OFF period as shown in the figure, thereby resulting in a just continuous (or critical) current mode of operation

Concept details c) DCM operation With the same (fixed) duty cycle, as the inductor value is reduced there comes a point when the current through the inductor becomes discontinuous - DCM operation Next, the inductor size should be further reduced (as depicted in the figure) till a point when the inductor current starts from the initial value of 0, reaches a peak Ip + (new) at the end of the ON period and then decreases slowly back to 0 before the end of the OFF period as shown in the figure, thereby resulting in a discontinuous current mode of operation Ip+(new) >Ip> Ip+

INSTRUCTIONS SLIDE Interactivity and Boundary limits expected in the animation In this section provide, interactivity options for all the parameters/components of the concept. For example:  Numerical values to change the state of the component: By providing input boxes  Drag and drop of components: To test the comprehension of the users  Movement of objects: To explain the action of the components Provide the boundary limits of the parameters, which will enable correctness of the results of the experiment gas

Interactivity and Boundary limits

INSTRUCTIONS SLIDE Questionnaire to test the user A small, (5 questions) questionnaire can be created in the next slide, to test the user's comprehension. This can be an objective type questionnaire. It can also be an exercise, based on the concept taught in this animation

Questionnaire 1. For a Boost type DC-DC converter, V O (output voltage) is: Answers: a) V i c) =V i d)‏ 0 2. The range of duty cycle (d) for DC-DC converters is: Answers: a) b) c) d)‏ 3. For a given power output, the peak current in the inductor of a DCM operated DC-DC boost converter is: Answers: a) less than the peak current in case of CCM b)equal to the peak current in case of CCM c) greater than the peak current in case of CCMd)‏ none of the above

4. The ripple in the inductor current of a CCM operated DC-DC boost converter is: Answers: a) greater than the current ripple in case of DCM b) equal to the current ripple in case of DCMc) less than the current ripple in case of DCM d)‏ none of the above 5. The expression of the output voltage of the Boost DC-DC converter operating in DCM is : Answers: a) b) V o is a complex expression of R, L and d c) d)‏ none of the above Answer key: 1(b), 2(d), 3(c), 4(c), 5(b) Questionnaire

INSTRUCTIONS SLIDE Links for further reading In the subsequent slide, you can provide links, which can be relevant for the user to understand the concept further. Add more slides in necessary

Links for further reading [1] “DC-DC Switching Regulator Analysis”, by Daniel M. Mitchell, McGraw-Hill Book Company, [2] “Power Electronics: Converters, Applications and Design”, by Ned Mohan, Tore M. Undeland and William P. Robbins, Third edition, John Wiley & Sons.

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