Power-one Italy S.p.a.

Abb Technology Ag

Abb Schweiz Ag

Andrea Marcianesi

David Martini

Massimo Valiani

Simone Soldani

There is described an electrical energy conversion system comprising: at least a first inverter () and at least a second inverter (), whose outputs are connected in parallel; at least a first DC voltage source (PV) connected to the input of the first inverter () and a second DC voltage source (PV) connected to the input of the second inverter (); a ground connection of the first inverter () and a ground connection of the second inverter (). The ground connection of said inverters comprises a ground connection branch (G;G) with a current sensor () which supplies a signal proportional to a leakage grounding current (I) measured in said ground connection branch (G;G). Through the signal proportional to the leakage current measured a feedback signal is generated to control the leakage current (I).

Control of leakage currents in systems with a plurality of parallel inverters

An energy conversion system and method perform active control of leakage current in multi-level grounded inverters. First and second subsystems each include positive and negative DC source terminals, at least first and second capacitors coupled between the positive and negative terminals to define a common bulk node for the respective subsystem, a DC/DC converter for regulating voltages across the capacitors, and an inverter. The inverters are coupled in parallel to an AC load. First and second grounding branches are homogenously coupled to terminals in the first and second subsystems, respectively, and to the same ground terminal. Control circuitry detects a leakage current value through the ground terminal, generates leakage current control signals for the respective DC/DC converters based at least in part on the detected leakage current value and a reference current value, and communicates the control signals to the DC/DC converters.

Earth leakage current control for a multi-level grounded inverter

The system provides for one or more photovoltaic panels () or other energy sources, connected to a series of inverters () in parallel, the outputs of which are connected to a load (Z) and/or to an electricity distribution grid (). One of the inverters operates as master unit and generates a power control signal in order to track the maximum power point that can be obtained from the panels (). The other inverters operate as slave units. The control is performed so that all the inverters absorb a variable quantity of power according to the fluctuations in the power available at the output of the photovoltaic panels () or other source subject to fluctuations.

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Arezzo, Italy

Andrea Marcianesi