Sma Solar Technology Ag

Sma Technologie Ag

Regine Mallwitz

Peter Zacharias

Bernd Engel

Jens Friebe

Klaus Rigbers

Benjamin Sahan

Samuel Vasconcelos Araújo

A transformerless inverter that serves to feed electricity from a DC current source into an AC power grid, has an inverter bridge and a DC/DC converter connected upstream of the inverter bridge. The DC/DC converter converts an input DC voltage that is present between two input lines of the inverter into a DC link voltage present between two input lines of the inverter bridge. The inverter bridge converts the DC link voltage present at the input lines thereof into an output AC voltage. The DC/DC converter includes at least one resonant circuit that has a resonance inductance and a resonance capacitance and is connected on its input side via at least two clocked switches to one of the two input lines of the inverter or an intermediate potential line carrying a potential in between. The input lines of the inverter and the input lines of the inverter bridge are galvanically isolated from one another by a capacitive method. The resonant circuit may be undivided and is connected alternately to the two input lines of the inverter bridge.

Transformerless inverter comprising a DC/DC converter

A circuitry arrangement includes several electronic parts mounted to a circuit board, at least one conductor section extending between the electronic parts within a first conductor layer, and a closed conductor loop comprising at least one loop section running in parallel to the at least one conductor section within a second conductor layer neighboring the first conductor layer. The closed conductor loop is configured to reduce a tendency towards oscillations of a current flowing through the conductor section in operation of the circuitry arrangement. The conductor loop is closed via at least one electronic component mounted to an outer surface of the circuit board.

Circuitry arrangement for reducing a tendency towards oscillations

In an inverter includes two input lines for connection to a DC voltage source, two half-bridges connecting the two input lines, and two output lines for connection to an alternating current load or an AC power grid. Each half-bridge includes two pulse-operated switches with reverse connected diodes, each output line is connected to a center point of one of the half-bridges via an inductance, and the two output lines are connected to the same one of the input lines via a further pulse-operated switch behind the inductance with respect to the associated half-bridge.

Inverter capable of providing reactive power

In a circuit apparatus for transformerless conversion of an electric direct voltage of a two-pole direct voltage source () connected to ground having a first voltage pole (+) and a second voltage pole (&#x2212;) into an alternating voltage, hazardous capacitive leakage currents are avoided by connecting the direct voltage source () to ground and the DC-AC converter () is operated at a controlled intermediate circuit voltage, a DC-DC converter stage () being connected between the direct voltage source () and the DC-AC converter (), said DC-DC converter stage providing at its output a +/&#x2212; voltage that is symmetrical with respect to the grounding point, two series-connected capacitors () having the same polarity and being connected to ground at their connecting point (V) and controlled are charged by two buck-boost choppers () connected one behind the other.

Circuit apparatus for transformerless conversion of an electric direct voltage into an alternating voltage

A direct current-direct current (DC/DC) converter operated in the resonant mode of operation for converting a direct input voltage into a direct output voltage with a bridge circuit located on the input side and incorporating switching elements, with a resonance circuit incorporating a resonance inductance and a resonance capacitance as well as with a high-frequency transformer for galvanic separation is disclosed, the transformer incorporates at least one primary winding and at least one secondary winding with at least two winding terminals each. The alternating current (AC) output of the bridge circuit is connected to the primary winding and a rectifier bridge with diodes to the secondary winding. A voltage boosting circuit array is connected downstream of the resonant circuit in such a manner that at least one additionally controllable switching element is contained, which is connected in parallel or in series to at least one additional diode or to at least one diode of the rectifier bridge on the secondary side, this array being connected in parallel to the high-frequency transformer so that the additional switching element short-circuits the resonance circuit in a triggered condition so that energy is stored in the resonance inductance and is delivered in the non-triggered condition.

System and method for a power converter having a resonant circuit

A three-phase inverter for converting DC power from a generator into three-phase AC power comprises a transformer for transforming two single phase alternating voltages with a fixed phase offset present at corresponding two primary windings into a three-phase alternating voltage present at secondary windings of the transformer. An inverter circuitry for receiving a direct voltage of the generator between two input lines and for supplying the two single phase alternating voltages to the two primary windings of the transformer is included in the three-phase inverter and comprises a split DC link having a center point connected to both input lines via corresponding capacitors and connected to a first terminal of each primary winding of the transformer, and two inverter half-bridges connected to both input lines, wherein a center point of each half bridge is connected to a second terminal of a corresponding one of the primary windings of the transformer.

Three-phase inverter for converting DC power from a generator into three-phase AC power

The object of the invention is a high-efficiency DC/DC converter, in particular for photovoltaic plants, incorporating a transformerless DC/DC converter operated in the resonant mode of operation for converting a unipolar direct input voltage with an associated positive pole (+) and with a negative pole (&#x2212;). There is imposed a resonance circuit incorporating at least one resonance inductance and at least one resonance capacitance, each resonance capacitance being connected to a respective one of the rectifier circuit arrangements in such a manner that the bipolar direct output voltage is provided, a voltage boosting circuit arrangement being connected to each resonance capacitance and to the rectifier circuit arrangement.

DC/DC converter

On an inverter for feeding power of a direct voltage source, in particular of a photovoltaic generator (PVG), into an alternating voltage mains (N), with an asymmetrically clocked bridge circuit with at least two first switches (S, S) clocked at mains frequency and with at least two second switches (S, S) clocked at a higher clock frequency, the efficiency is intended to be improved at low cost. This is achieved in that slow speed switches (S, S) of equal temperature stability are utilized for the mains frequency and that fast speed switches (S, S) with steeper switching slopes and higher temperature stability are utilized for the higher clock frequency, the fast speed switches (S, S) being locally separated from the slow speed switches (S, S).

Inverter with asymmetric clocking and thermally isolated modules

An inverter () for a grounded direct voltage source, in particular for a photovoltaic generator (), a battery or a fuel cell, for converting the direct voltage into an alternative voltage with a DC-DC converter () and a pulse inverter that is supplied by said DC-DC converter (), said DC-DC converter () being configured to be an oscillating circuit inverter and comprising a series resonant oscillating circuit, said DC-DC converter (), which is configured to be an oscillating circuit inverter, being configured to be a series-compensated oscillating circuit inverter with a choke (L) and a series-mounted capacitor array consisting of two or several oscillating circuit capacitors, a rectifier bridge branch including 2 diodes (D, D; D, D, . . . ), being connected to each of the partial oscillating circuit capacitors, said rectifier bridge branch being connected with its positive or its negative pole to output side intermediate circuit capacitors which are preferably connected in series so that said DC-DC converter () delivers at least two bipolar output voltages and is combined with the pulse inverter () with a divided voltage intermediate circuit that is supplied from the oscillating circuit inverter.

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Kassel, Germany

Regine Mallwitz