Senior Design II Mid-Semester Presentation

Single Phase Inverter Team Members Team Leader Electrical Engineer Control System Design Power Electronics Programming Website Electrical Engineer Output Filter Design Hardware Implementation Power Electronics Electrical Engineer Output Filter Design Programming Enclosure Website Electrical Engineer Hardware Implementation Enclosure Control System Design Christopher Burge Michael Robertson Johnny Reed Bret Hariel Faculty Advisor: Dr. Masoud Karimi

Outline  Problem  Solution  Technical Constraints  Practical Constraints  System Overview  Design Refinements  Testing Plan  Packaging  Timeline  Questions

Example of an inverter used to connect a distributed resources to a load

Problem  Adaptability of system components to change in distributed resource system parameters

Solution  An inverter which is capable of accepting variable DC inputs

Technical Constraints Name Description Voltage Regulation The voltage must stay within a 10% range centered on 120V. EfficiencyThis device must have an efficiency greater than 95% Total Harmonic Distortion The THD must be less than 5% Power RatingThe device must be able to deliver 400W Input Voltage Range The device must be able to output a voltage of 120V with an input range from 200 to 300VDC

Practical Constraints TypeNameDescription EnvironmentalEnclosureThe inverter enclosure must be weather proof from sun and rain. ManufacturabilitySizeThe inverter must be compact and weight less than 25lbs.

System Overview DC Source Output Filter Load Voltage Sensor Microcontroller Power Electronic Circuit Control to Power Isolated Interface

Design Refinement

Improvements  Voltage Sensing Circuit  DC Source Replacement

DC Source Replacement  Buck Converter  VLA DC/DC 24V to15V  UA78L00 15V to 5V DC Regulator  TLE2426 to obtain -15V DC

Buck Converter  Purpose: To supply power to all the elements that are not in the power electronic circuit  Challenge: How to supply power to the MOSFET of the buck converter on start up  Solution: Put a passive component circuit in parallel with the buck converter to supply microcontroller power

Schematic of Buck Converter

Additional DC/DC Regulators  Purpose: To supply all power from a single source  VLA DC/DC 24V to15V  UA78L00 15V to 5V DC Regulator  TLE2426 to obtain -15V DC

Voltage Sensor Circuit (old)  Problem High power loss in the voltage divider and additional voltage buses

Voltage Sensor Circuit (new)  Solution A sensor network that requires less power and a less diversity of voltage buses

Product Testing

Power Quality, Voltage Regulation, and Efficiency Power Quality: The THD must be less than 5% Voltage Regulation: The device must be able to output a voltage of 120V with a no more than a 10% deviance regardless of the load within our operating range Efficiency: This device must have an efficiency greater than 95%

Power Quality, Voltage Regulation, and Efficiency Power Quality: Using the Fluke 43B Power Quality Analyzer we will measure the total harmonic distortion Voltage Regulation: Using the Agilent DSOX302A4 Oscilloscope we will monitor the output voltage and compare it to a central tendency value of 120V Efficiency: Using the Fluke 43B Power Quality Analyzer we will measure the output power and compare it to the input power of the Sorensen XHR DC source.

Voltage Regulation LoadExpected Output Voltage Expected THD R = V1.24% R = V1.43% R = V1.01% R = V1.93% R = V0.87% R = 100, L = 250µ120.54V1.94% R = 100, L = 500µ120.54V1.94% R = 100, L = 1m120.73V2.83% R = 100, C = 5µ120.37V1.29% R = 100, C = 10µ120.40V0.5% R = 100, C = 20µ120.50V1.54% R = 100, C = 10µ, L = 500µ117.88V 0.7%

Variable DC Input The output voltage must stay within a 10% range centered on 120V. Test Conditions: Test 1: Vary the input power of the Sorensen XHR DC source from 200V to 300V Test 2: Vary the input power of the Sorensen XHR DC source from 300V to 200V Results:  Output remains within voltage regulation constraint

Max Power Rating The device must be able to deliver 400W Test Conditions: Three 100Ω power resistors placed in parallel to give a total of 33Ω to draw 400W to the load Results:  Pass  Fail

PCB & Packaging

PCB  PCB Design Software Options:  Cadence Orcad  Eagle  PCB Design Choice:  Eagle 5.11 Professional  Customizable libraries and ease of making parts

PCB Schematic Microcontroller Interface Circuit Power Electronic Circuit DC Source Voltage Sensor Load

PCB Layout 6” 10”

Enclosure Requirements  Manufacturability  Must exceed 10”x 8”x 4”  Must weigh less than 15lbs  Environmental  Must be NEMA 3R

Enclosure Options 12”x 10”x 5” 13.45”x 11.83”x 6.31” 8.25lbs $180 6lbs $86 [1] [2]

Timeline JanuaryFebruaryMarchApril Voltage Feedback Design Refinement PCB Design PCB Implementation Enclosure

References [1] L-com Global Connectivity. 12X10X Inch 120 VAC Vented Weatherproof Enclosure. Available: [2] Automation Direct. Premier (6in. X 6in. to 16in. X 14in.). Available: atalog/Enclosures/Non-Metal_%28NEMA_4X_-a- _3R%29/Premier_%286_in._X_6_in._to_16_in._X _14_in.%29

Senior Design II Mid-Semester Presentation Questions?