Sma Solar Technology Ag

Sma Solar Technologies Ag

Burkard Mueller

Jens Friebe

Markus Hopf

Oliver Prior

Torsten Leifert

Klaus Rigbers

Martin Putz

Wilfried Vogt

Andreas Jeppe

Hannes Knopf

A circuit arrangement for balancing a split DC link arranged between a first DC-voltage terminal and a second DC-voltage terminal is disclosed. The first DC-voltage terminal is connected via a first semiconductor switch to a first intermediate point that is connected via a second semiconductor switch to a bridge center point that is connected via a third semiconductor switch to a second intermediate point that is connected via a fourth semiconductor switch to the second DC-voltage terminal. A first terminal of a resonant capacitor is connected to the first intermediate point, and a second terminal of the resonant capacitor is connected to a DC-link center point via a connecting path, in which a resonant inductor is arranged in a series circuit with the third semiconductor switch, and which runs via the second intermediate point. An additional winding is magnetically coupled to the resonant inductor and a first terminal thereof is connected via a first diode to a first terminal of a countervoltage source, and a second terminal thereof is connected to a second terminal of the countervoltage source so that an energy coupled into the additional winding from the resonant inductor is discharged into the countervoltage source.

Circuit arrangement for balancing a split DC link

A power electronics device has a first power semiconductor switch and a driver circuit and enables a supply of electrical voltage to a driver circuit. An auxiliary circuit arrangement has a supply capacitor, an auxiliary capacitor, a normally off auxiliary semiconductor switch, a diode and a bootstrap diode. The auxiliary semiconductor switch is connected to a reference potential connection of the first power semiconductor switch via a connection point, starting from the connection point, a series connection of the diode, a second connection point and the auxiliary capacitor is arranged in parallel with the auxiliary semiconductor switch. When the auxiliary semiconductor switch is in the off state, the auxiliary capacitor is charged by the flow of current through the first power semiconductor switch.

Power electronics device and method for supplying electrical voltage to a driver circuit of a power semiconductor switch

A solar module includes a safety circuit, and a series circuit of bypass diodes, which is arranged between solar module connections, wherein the bypass diodes have bypass connections at both ends and all connecting points of the series circuit of bypass diodes. The solar module also includes a series circuit of solar partial modules having partial module terminals at both ends and all connecting points of the series circuit of solar partial modules, wherein each bypass diode is associated with precisely one solar partial module, and a plurality of semiconductor switches configured to disconnect the solar module connections from voltage at an associated partial module terminal when a disconnection signal is received by the safety circuit. Each of the plurality of semiconductor switches is configured to switch a solar partial module associated therewith into a voltage-free or current-free state, and at least one bypass connection is directly connected to an associated partial module terminal and at least one bypass connection is connected to an associated partial module terminal by means of one of the semiconductor switches.

Solar module and energy-generating system

The disclosure relates to a protective circuit for a photovoltaic (PV) module that includes an input having two input terminals for connecting the PV module, an output having two output terminals for connecting further PV modules of a series circuit comprising PV modules, a first switch for connecting one of the input terminals to one of the output terminals, and a controller configured to control the first switch, wherein the protective circuit further includes a series circuit including a first diode and an energy store, wherein the series circuit is arranged in parallel with the input of the protective circuit. The protective circuit also includes a second diode, which connects an output terminal of the protective circuit to a midpoint of the series circuit including the first diode and the energy store, and wherein a series circuit including the second diode and the energy store is connected in parallel with the first switch. The disclosure also relates to a method for operating a protective circuit according to the disclosure, and to a photovoltaic (PV) system including a series circuit comprising PV modules.

Protective circuit for a photovoltaic (PV) module, method for operating the protective circuit, and photovoltaic (PV) system having such a protective circuit

An inverter including a circuit arrangement configured to measure an insulation resistance is disclosed. The inverter includes at least one half-bridge including at least two switching elements extending between respective end points, and a grid disconnection point comprising a series circuit comprised of two disconnection devices. The series circuit is arranged between a center point of the half-bridge and an AC voltage terminal of the inverter, which AC voltage terminal is configured to connect to a phase conductor or a neutral conductor of an AC voltage grid. The circuit arrangement includes a resistor and a voltage measurement apparatus. The resistor is arranged electrically in parallel with one of the disconnection devices and the voltage measurement apparatus is arranged electrically between the output-side terminal of the resistor and one of the end points of the half-bridge.

Inverter having grid disconnection point and insulation resistance measurement and method for measuring an insulation resistance

A method for operating a transformerless inverter includes operating first and second half-bridges of the inverter using a unipolar clocking method as a first clocking method, determining a value of a grid-frequency stray current at the DC terminals of the inverter during the unipolar clocking method, and when a limit value is exceeded by the stray current value, operating the first and second half-bridges of the inverter using a stray-current-reducing clocking method as a second clocking method in which the first half-bridge provides an AC voltage at the first AC output, wherein an amplitude of the AC voltage is less than 50% of the amplitude of a voltage amplitude of the grid, and the second half-bridge provides a difference voltage between the grid voltage and the voltage provided by the first half-bridge at the first AC output.

Hybrid clocking method for single-phase transformer-free network inverters

A DC/DC converter includes a first low-voltage terminal point, a second low-voltage terminal point and a third low-voltage terminal point, and a first high-voltage terminal point and a second high-voltage terminal point. The first low-voltage terminal point and the first high-voltage terminal point are directly connected to one another, and an actively drivable switching element, a capacitor and a further switching element are connected in series between the first high-voltage terminal point and the second high-voltage terminal point. The capacitor is connected between the second low-voltage terminal point and the third low-voltage terminal point, a further capacitance is directly connected between the second low-voltage terminal point and the third low-voltage terminal point, and the further capacitance is decoupled from the capacitor at two terminals by two inductors, respectively.

DC/DC converter with a flying capacitor

A circuitry arrangement includes two-pole connectors for connecting a battery and a further voltage source. The plus pole of one connector and the minus pole of the other connector are directly connected to a plus pole and a minus pole of a DC voltage link. The plus and minus poles of the one connector are connected via a first parallel circuit of a switch and a diode and a first choke connected in series. The minus and plus poles of the other connector are connected via a second parallel circuit of a switch and a diode and a second choke connected in series. A connection between choke ends of the two parallel circuits is electrically conductive at least for alternating currents. The two chokes are magnetically coupled in that their winding senses on a common magnetic core are equal as viewed from the connection between the two parallel circuits.

Integrated solar and battery inverter

During measuring an insulation resistance for an inverter having at least one half-bridge including two active switching elements for driving an output current, and a DC link voltage, a center point of the half-bridge positioned between the switching elements is connected to a grounding point by closing a grounding switch, and the center point connected to the grounding point is connected, one after the other, to a first ungrounded terminal and a second ungrounded terminal of the DC link voltage of the inverter present at the half-bridge by means of the two active switching elements of the half-bridge to establish a connection between the first and second ungrounded terminals, respectively, and the grounding point. A current flowing via the connection to the grounding point is measured using a measuring device.

Insulation resistance measurement for inverters

The disclosure relates to a capacitor arrangement for an input circuit or intermediate circuit of a voltage transformer comprising at least two capacitors and two connection nodes. Switching elements are provided, by means of which the at least two capacitors are connected in parallel with each other in a first operating state and are connected in series with each other in a second operating state. The disclosure also relates to a voltage transformer arrangement comprising such a capacitor arrangement and an operating method for a capacitor arrangement.

Capacitor arrangement for an intermediate circuit of a voltage converter

A half-bridge of a bidirectional converter is divided into a first and a second conduction path connected in parallel. In each of the conduction paths a switching element and a freewheeling diode are connected in series, and the center points of the conduction paths are connected via a second inductor. The second inductor is connected in series with a first inductor which is connected to the center point of the second conduction path. The half-bridge has two operating modes. In each of the two operating modes the switching element in one of the two conduction paths is clocked at a high frequency to cause a flow of energy in one of two directions between a pair of high voltage-side connections and a pair of low voltage-side connections to the half-bridge. The two switching elements are of different types, the switching element in the first conduction path causing higher switching losses.

Bidirectional converter with preferential direction and reactive power-capable inverter having said converter

A circuitry includes first, second, and third switching elements, first and second storage inductors, two connector pairs, and first and second intermediate potential points. The second storage inductor includes first and second windings. The first intermediate potential point is connected to a first connector of the first connector pair via the first storage inductor, to the second connector of the first connector pair via the third switching element, and to the second intermediate potential point. The second intermediate potential point is connected to the first connector of the second connector pair via a series connection of the first switching element and the first winding of the second storage inductor, and to the second connector of the second connector pair via a series connection of the second switching element and the second winding of the second storage inductor.

Voltage converter comprising a storage inductor with one winding and a storage inductor with two windings

The invention is a method and electric circuitry for measuring a grounding current of a photovoltaic power system incorporating a photovoltaic inverter, a measurement current being led through two shunts disposed at different points. The measurement current is a current that may flow alternatively at two different points at different electric potentials, the current flowing at a potential that differs by at least 50 V from the potential of the point of evaluation. The shunts are inserted in such a manner in a current mirror circuit that the voltage drop caused by the measurement in the shunts generates an asymmetry in the current mirror the magnitude of which is proportional to the measurement current. The measurement current is the grounding current of the photovoltaic power system with optional positive or negative pole grounding.

Method for measuring a current, in particular by means of a grounding apparatus

A bidirectional inverter is disclosed, the inverter including DC terminals and being connectable to a grid via grid AC terminals. The inverter includes a first subinverter and a second subinverter, both subinverters being connected in parallel to the DC terminals, and being connected in parallel to the grid AC terminals by subinverter AC terminals. Each subinverter includes a full bridge and a switchable freewheel path, both being configured to drive current between the grid AC terminals in a driving direction, and configured to block a current between the grid AC terminals in a blocking direction opposite the driving direction. The driving direction of the first subinverter is the blocking direction of the second subinverter.

Bidirectional inverter for conversion between a direct current source and an alternating current grid

The invention is directed to a circuit array with a relay (K; K) incorporating a field coil (E) as well as a switch contact (), said switch contact () being provided as a switch point between a grid, in particular a mains supply (N), and an inverter (WR) fed by a direct voltage source, in particular by a photovoltaic generator (PVG), said relay (K; K) being configured to be a bistable relay.

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Kassel, Germany

Burkard Mueller