Electrical & Computer Engineering EECE 555 – Renewable & Efficient Electrical Power Systems
Homework 4 – Problem 1
Jennifer Johnson, November 8th 2017
Question: Search for a paper on maximum power point tracking and summarize its approach in
one paragraph. Comment on its comparison with the standard perturb and observe method
discussed in class.
Reference: Dallago, E., Liberale, A., Miotti, D., & Venchi, G. (2015). Direct MPPT Algorithm for
PV Sources with only Voltage Measurements. IEEE Transactions on Power Electronics, 30(12),
6742–6750. https://doi.org/10.1109/TPEL.2015.2389194
Answer: The paper explains a new method to track the maximum power point (MPP) of a
photovoltaic (PV) source with only voltage measurements. The authors performed numerical
simulations and experiments with a prototype involving a General Electric PV module. Using a
voltage sensor and other information available from the system, the MPPT voltage only method
reports better efficiency compared to the common perturb and observe (P&O) method. The
P&O method needs to calculate power, and therefore must measure both voltage and current.
The need to measure both voltage and current causes energy losses. Their MPPT method
incorporates an algorithm with an inverter interface to implement the proposed logic. Their
proposed inverter interface is called a double capacitor interface (as seen below) and includes a
circuit which tracks the MPP of the PV source and charges the dc link of the inverter. The
proposed inverter interface is made of two capacitors, two inductances and switches. The
control was implemented with a low-cost microcontroller and its internal ADC. In conclusion,
they found that in addition to being more energy efficient than the P&O method, that the
response time was also faster. They also found that it works in varying irradiance.
From analysis of the paper, I can see how it is probably a more advanced MPPT method than
current methods. But as it has only been tested in the lab, it would be interesting to understand
if a commercially available version would work and also what the comparative costs are.