Method and arrangement for tracking the maximum power point of a photovoltaic module

An arrangement for tracking a maximum power point of a photovoltaic module, the arrangement comprising:

• means for measuring output voltage (vC) of the photovoltaic module;
• means for determining output voltage (e) of an inverter connected to the photovoltaic module;
• means for measuring output current (i1) of the inverter connected to the photovoltaic module;
• means for defining a variable (z) relating to energy of a capacitor using the measured PV module output voltage;
• means for extracting a second harmonic component ({tilde over (z)}) from the defined variable (z);
• means for estimating a second harmonic component ({tilde over (p)}) of module output power (p) using the defined variable (z), measured output current (i1) of the inverter and the determined output voltage (e) of the inverter;
• means for multiplying the extracted ({tilde over (z)}) and the estimated ({tilde over (p)}) second harmonic components;
• means for extracting a DC component ({tilde over (p)}{tilde over (z)}DC) from a product ({tilde over (p)}{tilde over (z)}) of the multiplication of the second harmonic components;
• and
• means for forming a control signal (P;vref) for controlling the inverter connected to the photovoltaic module by using the extracted DC component in a PI algorithm.

A method of tracking a maximum power point of a photovoltaic module, comprising:

• measuring output voltage (vC) of the photovoltaic module;
• determining output voltage (e) of an inverter connected to the photovoltaic module;
• measuring output current (i1) of the inverter connected to the photovoltaic module;
• defining a variable (z) relating to energy of a capacitor using the measured PV module output voltage;
• processing the defined variable (z), measured output current (ii) of the inverter, and the determined output voltage (e) of the inverter to obtain second harmonic components ({tilde over (z)}), ({tilde over (p)}) of the defined variable and module output power (p), respectively;
• extracting a DC component ({tilde over (p)}{tilde over (z)}DC) from a product ({tilde over (p)}{tilde over (z)}) of the second harmonic components;
• and
• forming a control signal (P;vref) for controlling the inverter connected to the photovoltaic module based on the extracted DC component.