Skip to content

Maxim optimizer

The "Maxim Integrated" optimizers are DC-DC converters, connected to each sub-module of a PV module.

Therefore these devices have to be mounted within the PV module, in place of the by-pass diode: the PV modules including Maxim Integrated optimizers are specific modules in the database (available from several PV module manufacturers).

These optimizers perform the MPP tracking of each sub-module (20 to 24 PV cells), and work in the "Buck only" mode, i.e:

  • Below the Vmpp voltage the current is "boosted" along an Pmpp= (Impp * Vmpp) curve (hyperbola), up to a maximum current. This is achieved, for a given current I, by a Voltage diminution corresponding to the available Pmpp (Vout = Pmpp / I). In this way, operating the full string at a voltage below the unperturbated Vmpp will draw the maximum power of each sub-module.
  • For voltages over Vmpp, the optimizer's output follows then I/V curve of the sub-module.

Sub-array and system sizing

When sizing the Sub-array (namely determining the number of modules in series), the "Maxim" PV modules behave exactly in the same way as usual PV modules, except that the associated Maxim optimizer should be defined.

If you choose such a "Maxim" equipped module in the database, the corresponding optimizer will automatically be associated. And inversely if you choose a "Maxim" device in the optimizer's list, the suited modules (from different manufacturers) will appear in the module's list.

Now the Mismatch between PV modules (initial and evolving along the long-term degradation) is compensated by these optimizers: the mismatch loss parameter should be set as null.

The Optimizing effect on the Shading mismatch calculations (electrical shading loss) will only be taken into account when you define the "Module Layout" option.

Simulation

Any DC-DC converter has unavoidable efficiency losses.

As the optimizer is included within the PV module, the flash-test at the certifying laboratory, as well as at the output of the factory, is performed with the optimizer. Therefore the Nominal power (STC values of the datasheets) of the PV module includes the inefficiency of the Maxim optimizer.

Therefore during the simulation, the loss due to the basic inefficiency is null. Now as the efficiency slightly evolves with the buck ratio, the corresponding inefficiency increase should be accounted for. However the hours when the buck-ratio is significant (shaded situation) are not numerous, so that this additional inefficiency remains about negligible.