Power Electronics

# Power Electronics

## Power Electronics

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
##### Presentation Transcript

1. Power Electronics • Battery • Charging System • Supplying Power to Ink

2. Choosing the Battery • Battery Type has to first be chosen “Batteries and Charge Control for Stand-Alone Photovoltaic Systems : Fundamentals and Applications” , James P. Dunlop

3. Battery Capacity • How much energy is stored in the battery measured in ampere hours • Ah will provide ‘X’ amps of current for ‘Y’ hrs • Ah = Device Wattage (W) * Time to run (hrs)/ Battery Voltage (V) • From previous calculation we assume the total amount of power that we can use is 29,000 Wh/m2 , are prototype is 3’x5’ (0.92m x 1.525m) • Therefore the total power used in a year can be about 40,600Wh • Assuming snowfall for 240hrs a year (59 days for 4hrs) the average amount of power of the device will be 170W (40,600Wh/240h) • Therefore Ah = (170W*4h)/ 12V = 56Ah • To increase battery performance and life the battery should not be consistently discharged below 60% capacity so to be safe the battery capacity should be about 90aH

4. Battery Options • Trojan Deep-Cycle AGM Battery can be used • 31-AGM could all be options with 5hr rate-capacity of 82Ah • Can be purchased from civicsolar for \$270

5. Battery Chargers • Controls incoming charge of the battery • AGM batteries are INTOLERANT to overcharge • Standard Solar Chargers or MPPT (Maximum power point tracking) charger • MPPT chargers are much more efficient • Standard chargers can lose between 20-60% of the rated solar panel wattage

6. Choosing a Battery Charger • Charger needs to be able to handle rated watt, voltage, and current rating of PV panel (charging source) • Charging source is still being determined (Full Panel or select number of cells) • For now we can base the charger chose off a SBM solar 150W panel with the following specs:

7. Possible MPPT Charge Controller • Morningstar SunSaver 15 Amp MPPT Solar Charge Controller (\$225) Power used from possible 150W: Power= PV Panel Power * Efficiency Power = 150W * 97.5% Power=146.25 Charge Current = Power/Battery Voltage Charge Current = 146.25W/12V Charge Current =12.2A Charging Time = Battery Ah / Charge Current = 100Ah/ (12.2A) Charging Time = 8.2 hrs

8. Possible Standard Charge Controller • Morningstar SS-20L 20 Amp PWM Solar Charge Controllers w/LVD (\$78) Power used from possible 150W: Power = Voltage *Charge Current Power = 12V *8A Power = 96W about 66% efficient Charging Time = Battery Ah / Charge Current = 100Ah/ (8A) Charging Time = 12.5 hrs

9. Ink Power Supply Rtrace1 RTotal Rtrace2 Regulating Circuit Battery Rtrace3 I out Rtrace4