New ECE Building: Power Backup System

1. New ECE Building: Power Backup System ECE 445 Group #15 Neil Gebhardt Zach Reed Taylor Wu

2. Presentation Outline • Purpose and Goals • Design Overview • Hardware Design and Implementation • Software Design and Implementation • Analysis: Successes and Failures • Ethical and Other Considerations • Future Improvements

3. Purpose of the Project • To provide effective and efficient backup power to maintain operations during a power outage • To allow more time to properly shutdown any equipment to prevent damage or data loss. • Lower installation and operational costs for a backup generator system

4. Goals of Project • Immediate backup power to connected systems • Keep the primary systems powered with a battery for as long as possible • Intelligently manage the load so that the maximum amount of devices can remain powered

5. Hardware (Overview) • Uninterruptable Power Supply • Provides instantaneous power backup to outlets so that sensitive electronics remain on. • Switches and Outlets • Provide a means to disconnect an individual standard 120V 15A outlet from the UPS. • Controller • Allows interfacing of hardware with the software.

6. Block Diagram

7. Universal Power Supply • Uninterruptable Power Supply • Voltages were higher than expected on input side • 40V end-end, 20V from bridge, 14.1V from regulator • Voltage to outlets was normal at 120V

8. Bridge Implementation • Bridge with filter capacitor • Large Capacitor (2200µF) • Output voltage max: 5.59V min: 5.46V P-P: 0.13V

9. Block Diagram Voltage Regulator

10. Voltage Regulator Tests • Voltage Regulator • Smooth output max: 14.155V min:14.149 P-P: 0.0065V • Adjustable output with potentiometers

11. Relay Board • Relay Board to switch outlets • Use BJTs to drive coils with control chip

12. Relay Board Tests • Dual Coils • Each relay has two independent coils • Allows definitive switching • Switching with 3V puts 50mA across main coil

13. Sensing • 120V Power Indicator • Senses if the main voltage lines are on. • Backup Generator Current Indicator • Senses if backup generator is on • Battery Level Indicator • Allows reliable estimation of battery levels • Outlet Current Sensors • Allows measurement of power usage for each outlet

14. Block Diagram

15. Sensing – 120V Power Indicator • To help determine how the controller should be operating.

16. Backup Generator Current Indicator • ACT750-42L-F 250A current sensor • Output 0-10VDC depending on current • Was not implemented due to costs ($180) and lack of backup generator.

17. Battery Level Indicator • Battery used was 12V sealed lead acid from Embassy by Crown (12CE75). • 12.2V Fully charged and 10.5V being the End of Discharge Voltage for the battery.

18. Outlet Current Sensors • With a static voltage output, current draw determines power usage. • ACS715 Hall Effect Current Sensor, which can measure up to 20A. • Outputs 185mV/A.

19. Outlet Current Sensors 2A Input Test

20. Software (Overview) • Inputs • Determines controller Operation • Outputs • Opens or closes switches based on algorithm • Power Optimization • Deterministic algorithm that maximizes power usage.

21. MSP430 – Pin Diagram 1 – Dvcc – Digital voltage reference (high) 2 – A3 – Outlet 1 current 3 – A4 – Outlet 2 current 4 – A5 – Outlet 3 current 5 – A6 – Outlet 4 current 6 – A7 – Outlet 5 current 12 – P1.0 – Outlet 1 switch 1 13 – P1.1 – Outlet 2 switch 1 14 – P1.2 – Outlet 3 switch 1 15 – P1.3 – Outlet 4 switch 1 16 – P1.4 – Outlet 5 switch 1 20 – P2.0 – Outlet 1 switch 2 21 – P2.1 – Outlet 2 switch 2 22 – P2.2 – Outlet 3 switch 2 23 – P2.3 – Outlet 4 switch 2 24 – P2.4 – Outlet 5 switch 2 59 – A0 – UPS 60 – A1 – Main Voltage 61 – A2 – Generator Current 62 – AVss – Analog reference (0V) 63 – DVss – Digital voltage reference (low) 64 – AVcc - Analog reference (~3V)

22. Software Algorithm • Overview

23. Software Algorithm Tx = time outlet x is on. Wx = weighted value of outlet x (delivered from RS232) Px = power being dissipated at outlet x Total Weight = T1*W1+T2*W2+T3*W3+T4*W4+T5*W5 Battery Energy = T1*P1+T2*P2+T3*P3+T4*P4+T5*P5 • Want maximum value of Total Weight (TW) • Six dimensional equation (T1-T5 and TW )

24. Finding Maximum • Set a time cap • Generator starts after some time • Helps balance time each outlet is on • Start at origin • TW increases with time • Find the max in each direction • Recursive

25. Finding Maximum • Incrementally head in direction of max • Subtract power of direction from energy • Similar TWs: move in direction we've moved the least (balances times) • Zero weight: never move in that direction • Repeat until out of power • Time cap reached at all non-zeros • Give rest of time to outlet that gives most weight for time left • Balance similar TW

26. Software Algorithm Tests: Battery Energy = 200 Time cap = 20

27. Analysis: Successes and Failures • Success: Input side of UPS performs well, relay system is reliable • Failure: UPS inverter was not implemented • Success: Sensing for voltages and currents • Failure: Unable to interface to MSP320 • Success: Algorithm gives desired output signals from MSP430 • Failure: Bigger MSP430 did not work; lack of input analog signals

28. Ethical and Other Considerations • Actual vs Implied performance • Should not imply that the system can perform better than it does. • Accurate Sensing • Without accurate sensing, controller cannot have proper decision making. • Proper decision making • Able to operate as user intended

29. Future Improvements • Design sub-systems so that most can be independent of the control system. • Friendly graphics user-interface, especially to make weighting each outlet easier. • Higher grade equipment to supply at actual expected power, standard being 120V 15A.

30. Thank You For Your Time Questions?