Fronius International Gmbh

Richard Grasböck

Christian Fasthuber

Harald Josef Kreuzer

Stefan Wieser

Roland Pieler

Michael Rothboeck

Johannes Graf

Method for optimizing a maximum power point of a solar cell stack having modules, each including an MLSD unit, and an inverter. The MLSD unit shuts down the module when module voltage falls below a first voltage threshold, and switches it on, when a predefined second voltage threshold is exceeded. For optimal performance, the solar cell stack carries out: Defining, changing an electrical control parameter to a first wait value so that the second voltage threshold is exceeded exceeded; maintaining first wait value for a first time period so the modules are switched on by the MLSD units; changing electrical control parameter to a threshold value in a variation range and determining current-voltage curves for the modules in variation range; determining maximum stack power from current-voltage curves of the modules in the variation range; and predefining the determined maximum stack power as the maximum performance point.

Controlling a solar power plant

To improve voltage balancing at the DC link capacitor voltages of a multi-level inverter with a split DC link a modulation signal with a modulation signal amplitude as even harmonic signal of the output voltage or output current of the inverter is calculated from an actual electric power difference of the actual electric powers at the DC link capacitors and is superimposed onto the setpoint value for setting an output voltage or output current of the inverter.

Method for controlling a multilevel inverter with a split DC link

Growing community of inventors

Wels-Thalheim, Austria

Richard Grasböck