NOVELTY - The photovoltaic module is connected to a maximum power point tracker (MPT, MPP or MPPT) determining maximum module power and adjusting the working voltage-current point of the DC-AC inverter (14). The detector unit (40) determines the voltage of the solar cells and generates a control signal for the MPP unit (42). Reacting to a predetermined voltage change at a solar cell, relative to voltages of other cells of the photovoltaic module, the control signal causes power variation, especially power reduction, of the photovoltaic module. This is achieved by shifting the voltage-current working point.    USE - A controller for a photovoltaic solar power array.    ADVANTAGE - The new arrangement optimizes power output, whilst minimizing degradation of the solar cells. It prevents damage to individual cells caused by shading. The number of costly bypass diodes required is reduced, or they are eliminated entirely. Energy output during shading is increased in comparison with earlier designs. Performance is increased over the entire life of the cells.    DETAILED DESCRIPTION - The detector is designed to detect predetermined variation corresponding to shading of the cell. To measure the respective cell voltages, a corresponding number of analysis lines are provided and connected to the detector unit (40). The MPP unit has a parameter detector (40) determining illumination and temperature of the cells. A comparator is used to detect relative changes in relation to predetermined values. When such changes occur, the voltage-current working point is shifted accordingly. Non-volatile memory stores the comparison values. The detector has a temperature sensor determining the operating temperature of the solar cells. It includes a light sensor determining direct or partial light incidence on the photovoltaic module. The photovoltaic module and/or the solar cells have no bypass diodes. The solar cells are organic- or thin-film inorganic types. The voltage-current working point is shifted such that in the operating state, none of the solar cells has a negative electrical current passing through it. Cell-specific limiting tolerances are not exceeded.    DESCRIPTION OF DRAWING(S) - The drawing shows a simplified block schematic circuit diagram of the control circuitry.    DC-AC inverter (14)    detector unit (40)    MPP unit (42)