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Procedure and control device for photovoltaic pumping systems. Procedure and control device (4) for pumping systems that by means of a pid algorithm regulates the frequency of operation of the frequency inverters (2) connected between a photovoltaic generator (1) and the pumping unit (3), in order to maintain the generator voltage (1) in the environment of a set voltage and above the minimum supply voltage of the frequency inverters (2). When it detects a sudden fall of the dc voltage of the generator (1) below a first threshold, the control device (4) deactivates the pid algorithm to establish a frequency lower than the frequency of operation of the frequency inverters (2) and a minimum slope of abrupt deceleration for a rise in the voltage of the frequency inverters (2). When it is detected that the dc voltage returns above a second threshold, the pid controller of the control device (4) is reactivated. (Machine-translation by Google Translate, not legally binding)

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1. A control method for photovoltaic pumping systems comprising: - measuring an output voltage of a photovoltaic generator (1), - establishing a reference voltage corresponding to a maximum power point of the photovoltaic generator (1) for pumping systems with variable flow and pressure and corresponding to a power point demanded from the photovoltaic generator (1) by the pumping system for pumping systems with constant flow and pressure, - a proportional-integral-derivative (PID) algorithm, which acts on at least one variable-frequency drive (2) connected to the output of the photovoltaic generator (1) and which establishes an operating frequency, the PID control algorithm being configured for: - reducing the operating frequency of at least one variable-frequency drive (2) when the measured output voltage of the photovoltaic generator (1) is lower than the established reference voltage, - increasing the operating frequency of the at least one variable-frequency drive (2) when the measured output voltage of the photovoltaic generator (1) is greater than the established reference voltage; the control method characterised in that it further comprises the following steps: - establishing a first threshold voltage value that is greater than a minimum operating voltage of the at least one variable-frequency drive (2); - when the voltage measured at the output of the photovoltaic generator (1) drops below the first threshold voltage value, deactivating the PID control algorithm and establishing a reference frequency for the at least one variable-frequency drive (2) that is lower than the operating frequency, and establishing a minimum gradient of sudden deceleration to make the at least one variable-frequency drive (2) enter into a regenerative braking mode which produces an increase of the operating voltage of the at least one variable-frequency drive (2). 2. The method according to claim 1, characterised in that it further comprises establishing a second threshold voltage value that is greater than the first threshold voltage value and when the voltage in the photovoltaic generator (1) exceeds the second threshold voltage value, activating the PID control algorithm. 3. A control device (4) for photovoltaic pumping systems that comprise at least one pumping unit (3) connected to the output of at least one variable-frequency drive (2) which, in turn, is connected to the output of at least one photovoltaic generator (1), the control device comprising a proportional-integral-derivative (PID) controller, configured for: - reducing the operating frequency of the variable-frequency drive (2) when at the output of the photovoltaic generator (1) the PID controller measures a voltage lower than a reference voltage corresponding to a maximum power point of the photovoltaic generator (1) for pumping systems with variable flow and pressure and corresponding to a power point demanded from the photovoltaic generator (1) by the pumping unit for pumping systems (3) with constant flow and pressure, - increasing the operating frequency of the variable-frequency drive (2) when at the output of the photovoltaic generator (1) the PID controller measures a voltage that is greater than the reference voltage; the control device (4) characterised in that it also comprises processing means configured to deactivate the PID controller when at the output of the photovoltaic generator (1) the PID controller measures a voltage below a first threshold voltage value, the first value being greater than a minimum operating voltage of the variable-frequency drive (2); and, deactivating the PID controller, establishing a reference frequency for the variable-frequency drive (2) lower than the operating frequency thereof, and establishing a minimum gradient of sudden deceleration to make the variable-frequency drive (2) enter into a regenerative braking mode that produces an increase in the operating voltage of the variable-frequency drive.(2). 4. The control device (4) according to claim 3, characterised in that the processing means are configured to also activate the PID controller when at the output of the photovoltaic generator (1) the PID controller measures a voltage that is greater than a second threshold voltage value which, in turn, is greater than the first threshold voltage value. 5. The control device according to any of claims 3-4, characterised in that it is a programmable logic controller (PLC). 6. The control device according to claim 5, characterised in that it is connected to the control of the variable-frequency drive (2). 7. The control device according to claim 5, characterised in that it is integrated in the variable-frequency drive (2).

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