Abstract: A method and arrangement for operating a pump system are disclosed, the pump system including a pump arranged to be rotated with an AC motor, an inverter, the output of which is electrically connected to the AC motor, and a photovoltaic panel system electrically connected to feed DC power to the inverter. The method can include setting a voltage limit, and determining continuously voltage obtained from the photovoltaic panel system. When the determined voltage of the photovoltaic panel system is below the set voltage limit, frequency of the inverter can be controlled such that the ratio between output voltage of the inverter and the output frequency is substantially constant. When the determined voltage of the photovoltaic panel system exceeds the voltage limit, the inverter frequency can be controlled for keeping voltage of the photovoltaic panel system substantially at the voltage limit.

Abstract: A method and arrangement for operating a pump system are disclosed, the pump system including a pump arranged to be rotated with an AC motor, an inverter, the output of which is electrically connected to the AC motor, and a photovoltaic panel system electrically connected to feed DC power to the inverter. The method can include setting a voltage limit, and determining continuously voltage obtained from the photovoltaic panel system. When the determined voltage of the photovoltaic panel system is below the set voltage limit, frequency of the inverter can be controlled such that the ratio between output voltage of the inverter and the output frequency is substantially constant. When the determined voltage of the photovoltaic panel system exceeds the voltage limit, the inverter frequency can be controlled for keeping voltage of the photovoltaic panel system substantially at the voltage limit.

Abstract: A method and arrangement are disclosed for operating a pump in pump system having a photovoltaic panel system, an inverter electrically connected to the photovoltaic panel system, and a motor driving the pump and electrically connected to the output of the inverter. The method can include setting a voltage limit for the inverter, monitoring the voltage produced by the photovoltaic panel system, operating the inverter for rotating of the motor when the voltage produced by the photovoltaic panel system is above the voltage limit, and disabling use of the inverter when the voltage of the photovoltaic system remains below the voltage limit.