1. Photovoltaic Systems Engineering Electronic Control Devices (ECDs)
SEC598F17
Photovoltaic Systems Engineering
Session 14
Electronic Control Devices (ECDs)
Charge Controllers
Inverters
October 05, 2017

2. Session 13 content Charge Controllers Inverters Purpose, utility
Operation, reliability, failure mechanisms

3. Learning Outcomes
Introduction to the power electronics used in PV systems
Recognition of the importance of controllers and inverters to the operation of certain PV systems

4. PV Systems – Charge Controllers
Pulse Width Modulation (PWM) – Duty Cycle Vm
v(t)
Vavg
ton
toff
time

5. PV Systems – Charge Controllers
Pulse Width Modulation (PWM) – Duty Cycle

6. PV Systems – Charge Controllers
Pulse Width Modulation (PWM) – Duty Cycle

7. PV Systems – DC-DC converters
Boost converter
The transfer characteristic is:
en.wikipedia.org/wiki/Boost_converter

8. PV Systems – DC-DC converters
Boost converter ON
OFF

9. PV Systems – DC-DC converters
Buck converter
The transfer characteristic is:
en.wikipedia.org/wiki/Buck_converter

10. PV Systems – DC-DC converters
Buck converter

11. PV Systems – DC-DC converters
Buck-Boost converter
The transfer characteristic is:
en.wikipedia.org/wiki/Buckboost_converter

12. PV Systems – DC-DC converters
Buck-Boost converter

13. PV Systems – DC-DC converters
Summary
Boost Converter
Buck Converter
Buck-boost Converter

14. PV Systems – DC-DC converters
Summary
Boost Converter
Toyota Prius
LED Lamps
Buck Converter
Impedance matching
Charge controllers
Buck-boost Converter

15. PV Systems – Charge Controllers
12V, 24V, 48V
45A, 70A, 100A
1600W, 3200W

16. PV Systems – Charge Controllers
Charge controller block diagram
Isolation of PV array
and battery
Protection from
overcharging
Protection from deep
discharging

17. PV Systems – Charge Controllers
Charge controller operation

18. PV Systems - Maximum Power Point Tracking
The PV system produces electrical power and is best
utilized when the maximum power produced can be
fully delivered to the electrical “load” – this can only
happen when the power source and the power load
“match”
C.S.Solanki, Solar Photovoltaic Technology and Systems

19. PV Systems - MPPT
Other representative electrical loads

20. PV Systems - MPPT An approach to assuring a better match is the use of
Maximum Power Point Tracking (MPPT) – an electronic technique
that moves the operating point along the maximum power
hyperbola (I*V = constant) associated with the PV array until it
intersects the electronic load IV characteristic

21. PV Systems - MPPT
IMPPT
Imp
VMPPT
Vmp

22. PV Systems - MPPT
Imp
IMPPT
MPPT
Vmp
VMPPT

23. PV Systems - MPPT Perturb and Observe
PV operating points from P&O algorithm
N.Fermia et al., Power Electronics and Control Techniques for Maximum
Harvesting in PV Systems

24. PV Systems - MPPT Perturb and Observe Time domain behavior
N.Fermia et al., Power Electronics and Control Techniques for Maximum
Harvesting in PV Systems

25. PV Systems - MPPT
Perturb and Observe
P&O flowchart

26. PV Systems - MPPT Perturb and Observe
N.Fermia et al., Power Electronics and Control Techniques for Maximum
Harvesting in PV Systems

27. PV Systems - Inverters
The inverter is the essential electronic system that converts the DC electrical output from the PV array into the AC electrical input for the residence, national electrical grid, and so on
INVERTER
DC input
AC output

28. PV Systems - Inverters
Heart of the inverter – the “H-bridge”

29. PV Systems - Inverters
The H-bridge in operation

30. PV Systems - Inverters The output of the inverter is controlled
by pulse width modulation (PWM)

31. PV Systems - Inverters State of the Art Inverters:
High efficiency – 98% or higher
Dual independent MPPT systems
Integrated DC disconnect and combiner inputs
No fans or electrolytic capacitors

32. PV Systems - Inverters
J.M.Jacob, Power Electronics: Principles and Applications