FW15 MPPTs
- Aryan Kashem
Maximum Power Point Tracking (MPPTs). We are making our own board , this page will cover the firmware design decisions.
Perturb and Observe
The basic algorithm that constantly adjusts boost-converter switching frequency, and thus the voltage output to maximize power. This algorithm assumes that by maximizing the input power, it can maximize the output.
Incremental Conductance
Incremental conductance relies on the fact that the maximum power is when dP/dV = 0. The algorithm detects the slope of the P-V curve and searches for the peak of the P-V curve.
If dP/dV is positive, the nearest power maximum is at a higher voltage.
If dP/dV is negative the nearest maximum is at a lower voltage.
When dP/dV is 0, the maximum power has been reached
dP/dV = d(I x V)/dV = I dV/dV + V dI/dV = 0,
Therefore, dI/dV = -I/V,
where dI/dV is the incremental conductance and I/V is the instantaneous conductance.
We will use an improved incremental conductance algorithm as proposed in the following research paper:
Outer Control Loop
There is a maximum charge voltage for the pack. Make sure we don't reach that by pre-emptively taking the slope and ensuring our current dV/dT is not projected to surpass the max charge voltage.