Lafayette Photovoltaic Research and Development System 2010

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

What is the Lafayette Photovoltaic Research and Development System? PV Array Subject to a Statement of Work Commercial Grid Tie Inverter Requirements based team oriented capstone project 2kW solar energy system that converts high voltage DC to 120V AC RMS signal of 60Hz A test space for students to learn about energy issues and power engineering.

Main Requirements Automatic charge and discharge the LiFePO 4 batteries Delivery of 120V RMS, 60Hz ± 0.05% AC Monitor, store and display real time temperature, voltage, and current data from all subsystems Safety precautions to safely shut down the system if a fault is detected

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

Project Team Began in 2009 with a 22 student and 2 professor team 2010 team consists of 14 students along with the 2 original professors. Over 40 people have contributed to this project

Systems Engineering Exposure Much of today’s engineering is system engineering – System architecture issues – Interface design and documentation – Configuration management – Scheduling Opportunity to manage complexity

Other Engineering Exposure Exposure to mechanical issues – Most ECEs have little exposure to mechanical issues Board layout Subsystem Box layout Assembly drawings Exposure to safety issues – Safety lecture – Safety plan Students limited to 30V Lock out tag out – Must design with safety in mind! High voltage isolation HV/LV separation

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

System Block Diagram

System Block Diagram - PV PV Array converts solar energy to electrical energy

System Block Diagram - RPI The RPI Accepts high voltage DC from the PV array and delivers it to the rest of the system Main safety hub

System Block Diagram - ESS Battery Bank consisting of V Lithium Iron Phosphate Batteries Creates 12V for other systems

System Block Diagram - FIB Receives high voltage DC and converts it into a 120V RMS sinusoidal AC signal of 60 Hz

System Block Diagram - SC Regulates the high voltage path between the PV, batteries (ESS), and the filter/inverter (FIB)

System Block Diagram - SCADA Higher-level operation Data collection of the other subsystems.

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

2009 vs Subsystem Comparison Subsystem2009 Status2010 Status RPIMade complete subsystemReused 2009 subsystem with minor rework ESSMade complete subsystemReused 2009 subsystem with minor rework FIBPrototype made but explosion occurred and also did not meet frequency or THD specifications Using the same topology; made a new filter and inverter that meets specifications SCNot madeCreated a new subsystem to better enable battery and energy management SCADANot Integrated with rest of system, but made Data Acquisition boards Used 2009 Data Acquisition Boards with minor rework and used ~100 lines of last years code. Added ~5000 lines of code and working website monitoring and displaying both LPRDS and the Sunny Boy

2009 vs Miscellaneous Comparison 2009 Status2010 Status PCB Boards DesignedDesigned 7 (1 redesigned twice) Reused 1, redesigned 1, and designed 1 from scratch Demo App and Tower Aesthetics Had a poster with LEDs that was displayed on the tower; PicoLCD Commercially bought lettering; PicoLCD; bright LED’s; Demo App using LCD display monitor Cables kits1422 Subsystems4Reused 2, redesigned 1, designed 2 Subsystem Connectors2740

2009 to 2010 Major Changes Power management algorithm (SC) Working inverter/filter Integrated SCADA Demonstration application

2009 Top Level Diagram Comparison

2010 Top Level System Diagram

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

System Testing Subsystem QA Low Voltage Testing – Basic System Functionality – Battery Management High Voltage Testing Reliability and Maintainability

Switch Controller (SC) Regulates the high voltage path between the PV, batteries (ESS), and the filter/inverter (FIB) Student Designed Data Acquisition PCB Board Student Designed Box Layout and Wiring Scheme

SC ALGORITHM

BATT MGMT APP STATE TRANSITION DIAGRAM SoC Thresholds: 100% = 235V 65% = 205V 55% = 195V 20% = 165V

State of Charge

Low Voltage Testing Connect the system for DC Load Integration PV DC Source Disconnect FIB DC Load

Force LPRDS through all possible state transitions Attempt illegal state transitions Low Voltage Testing- Basic Functionality

Force the SC through all possible state transitions Two transitions should not occur Low Voltage Testing- Battery Management

Reliability and Maintainability Test Run the DC Load Integrated system for 24 hours No unexpected faults or failures occur No components overheat

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

Filter Inverter Box (FIB) Consists of: – H-Bridge – Low Pass Filter – Microcontroller FIB PICTURE Receives high voltage DC and converts it into a 120V RMS AC signal of 60 Hz Student Designed Low Pass Filter Student Designed H Bridge PCB Board Student Programmed Microcontroller Student Designed Box Layout and Wiring Scheme

AC Inverter Microcontroller controls IGBT inputs by Pulse Width Modulation 4 high power insulated gate bipolar transistors (IGBT’s) in H-bridge – Allows voltage to be alternated in opposite directions to create sine wave

Filter/Transformer Filter – Removes switching frequency – THD of less than 3% required Transformer – Reference output of FIB to building ground – Isolates the connection to the load

FIB Testing Requirements Frequency = 60Hz ±.05% Amplitude = 120Vrms ± 5% Total Harmonic Distortion (THD) < 3% Conducted emissions requirement of average Amplitude at 150KHz < -54dB and peak at 150KHz of < -41dB

Frequency Testing Test setup – Oscilloscope with inputs from: Signal generator Differential output of filter – Hold one waveform on scope and time a full cycle of the other waveform across the first waveform – The inverse of this time is the frequency difference

Frequency Results Time 204s Frequency difference 1/204s.0049Hz Spec: 60Hz±.05% Measured: % Result………..PASS

Amplitude Testing Set power supply to nominal battery voltage (205Vdc) Plug in wall transformer to output of system Measure the RMS voltage on oscilloscope Scale by factor of transformer Specification: 120VACrms ± 5% Result: 119VAC ….……………………………….. PASS

Capture waveform on digital oscilloscope Import data into MATLAB Write program to calculate THD Run program Specification: 3% THD THD Testing

THD Results THD calculated to be.157% PASS

Conducted Emissions Testing Capture data on a digital oscilloscope Import data into MATLAB Calculate the FFT from the output waveform Examine results above 150KHz

Conducted Emissions Results Peak at dB…………………………………………………………………………………Inconclusive

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

Supervisory Control and Data Acquisition (SCADA) Controls higher level operation and collects data from each subsystem – State Manager App – Battery Management App – Maintenance App – Demo App

Software Top Level Diagram

Data Acquisition Boards Reused from last year with a few minor changes. 4 boards total: RPI DAQ, ESS DAQ, SC DAQ, and FIB PCB. Serve as a hardware interface to sensors and switches.

Sunny Boy Communication Communication established with the Sunny Boy inverter using RS-485. Did not have to buy the Sunny Beam, saving $280 Available Sunny Boy Data: – Total energy saved – Voltage and current being delivered to the grid – voltage and current drawn from the PV array – AC output frequency

MySQL Database Stores system information – Sensor Readings – Fault and Event Logs – System State Allows for long term data analysis – Solar panel performance by month or season – energy generated per year Space to store over 5 years of data Provides the website with data

Website Directly interacts with the database using PHP. View data from any sensor over a specified date range. View logs stored in the database over a specified date range. lprds.aec.lafayette.edu

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

Tower Display LED indicator lights Demo App on LCD display Pico LCD indicating system state FIB & SC- digital meters for voltage, current, and temperature System output- Analog gauges showing voltage and frequency

Demo App Goal: educate passersby about LPRDS and demonstrate system capabilities Simple descriptions, diagrams and live data Simple user interface Coded in C++ using QT and the LPRDS API Upcoming Hardware Expansions – Touch sensor navigation – Demo outlet control

Demo App Screenshots

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

Safety Loop Safety is an integral part of our system – Each subsystem contains part of the safety loop – Safety loop must be closed in order enter and stay in the operational state Safety loop consists of 4 wires – Two for the loop itself – “Safety 12” which signals if the safety loop is closed – “Safety 12” ground

Safety Loop Diagram

Safety Loop Hardware SCADA Interface Box (SIB) – Purchased for USB controlled relay & digital input ports – Added feature of two RS485 ports Safety to Software Interface Board – Designed to control the alarm – Ends the safety loop with the big red emergency button ALARM

Presentation Outline System Introduction Project Team System Block Diagram 2009 vs Comparison 2010 System Focus – Switch Controller (SC) – Filter Inverter Box (FIB) – Supervisory Control and Data Acquisition (SCADA) – Demo App and Tower Design – Safety Loop and Hardware Project Status

Budget – Current Spending Section Breakdown SCADA$ Conn. & Cables$ FIB$ ESS$ SC$ DAQs$ Snubbers$ Andy Misc.$ AC Load$ TOTAL SPENT:$ 2, Remaining:$

Power Budget RPI: 3.89W ESS: 1.42W SC:.9W FIB: 6.03W SCADA: 7W Safety & Display: 1.29W DAQ Boards: 3.99W Total: 25W Amount Allowed: 37.5W

Major Requirements Achieved Raw Power Interface – Contains main logic for safety Energy Storage System – ESS provides LVDC power for all subsystems Filter-Inverter Box – Provide 120V RMS, 60Hz AC power Supervisory Control And Data Acquisition – Perform supervisory functions on all subsystems – Log system data (sensors, states) into the database, retrievable on the website Safety – All subsystems must be connected to the safety interface Demo and Display

Major Requirements to be Achieved Switch Controller – Switching algorithm Supervisory Control And Data Acquisition – Operational States Power Independence – FIT PC, display monitor Documentation – Must be complete and correct

Major Requirements Not Achieved Energy Storage System – Per-cell management – Standalone operation – Internally protected from excessive charge/discharge Filter-Inverter Box – Measure phase angle between voltage and current, and power factor Supervisory Control And Data Acquisition – Monitor voltage, current, and temperature in all subsystems HV PV Integration

Future Improvements Meet the requirements we are not meeting – Snubbers for when incorporating PV Array – Single Cell Battery Management – Power independence System Control via website Maximum Power Point Tracking Demo Touch Sensors

Special Thanks To: Dr. Jemison Professor Nadovich Andy Langoussis Nicolette Stavrovsky

Questions?