Power-one Italy S.p.a.

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David Martini

Sauro Macerini

Massimo Valiani

Andrea Marcianesi

Simone Soldani

Fabio Tombelli

Silvia Mastellone

Stefan Almer

Silvio Scaletti

Pietro Raboni

Antonio Canova

Ettore Marroni

A DC/AC converter is provided with a new control device and method for managing inrush current transients during operation without requiring additional external devices or emergency operating modes forcing the DC/AC converter to shut down. The present invention is particularly, but not exclusively, aimed at grid connected DC/AC, converters, often subject to inrush current phenomena due to perturbations in the grid.

DC/AC converter comprising control means for inrush current protection

Multi-level inverter introducing a new topology wherein standard IGBTs can be employed in place of common emitter IGBTs, wherein switching and conduction losses are minimized and wherein the number of implemented levels can be easily increased with the addition of a minimum number of components.

Multi level inverter

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

The multi-level DC/AC converter, comprising: an input () connectable to a direct voltage source (), with a first connection () and a second connection () between which can be applied an input voltage (Vi); a half-bridge with a first controlled switch () and a second controlled switch () between which is positioned an output (U) of the converter; a first connecting branch () between the first controlled switch () and the first connection () and a second connecting branch () between the second controlled switch () and the second connection (); a third controlled switch () associated to the first controlled switch (), connectable in series to the first controlled switch to generate an output voltage exceeding a first limit value (Vi/2); a fourth controlled switch () associated to the second controlled switch (), connectable in series to said second controlled switch to generate an output voltage below a second limit value (&#x2212;Vi/2).

Five-stage neutral point clamped inverter

The plant comprises: a DC-voltage electric power source (), whose operating conditions vary as a function of at least one uncontrollable quantity, for each value of the uncontrollable quantity the source presenting a characteristic curve of the supplied power as a function of a controlled quantity, wherein each characteristic curve presents a maximum for an optimal value of said controlled quantity; a power conditioning circuit (); a regulation loop () to adjust the controlled quantity maximizing the power supplied by the source when said uncontrollable quantity varies. The regulation loop is de-signed in such a way as to determine whether, for the actual value of said uncontrollable quantity, the actual value of the controlled quantity (V.in) is greater or lower than the optimal value and to generate a regulation signal (V.in-REF) to modify the actual value of the controlled quantity towards the optimal value.

Method and system for extracting electric power from a renewable power source

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.

Delivery of electric power by means of a plurality of parallel inverters and control method based on maximum power point tracking

A method of controlling an inverter to includes determining the components of a phasor representing the output current from the inverter in a fixed reference system; determining the components of the current phasor in a reference system rotating at a velocity equal to the velocity of rotation of the phasor representing the grid voltage; and comparing the components of the current phasor in the rotating reference system with a reference, again expressed in the rotating reference system, to determine an error signal, by means of which the inverter is controlled.

Method and device for the control of a three-phase inverter

A circuit for controlling the power supply voltage of an electric motor includes means for detecting the difference between a mains voltage and a reference voltage, and means for generating alternating correction voltage whose frequency is equal to the frequency of the mains voltage and which is phase-shifted with respect to the mains. The phase shift between the mains voltage and the correction voltage is proportional to the between the mains voltage and the reference voltage, and the correction voltage is added to the mains voltage.

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San Giovanni Valdarno, Italy

David Martini