Sma Solar Technology Ag

Burkard Müller

Jens Friebe

Marcel Kratochvil

Alexander Unru

Lars Bethke

Bethke Lars

A power converter between an AC side and DC of the power converter is disclosed. The AC side is connected to an AC supply grid and the DC side is connected to a DC grid. The power converter includes a bridge circuit connected to the AC side of the power converter via AC switches and connected to the DC side of the power converter via circuit breakers, wherein a DC link circuit of the power converter is chargeable from the AC supply grid via an AC precharging circuit. The power converter has an insulation monitor to measure the insulation resistance of the DC side when the AC precharging circuit is connected to the DC link circuit. The disclosure also includes a related method.

Power converter for transferring power between an AC side and a DC side, and power supply method

The application describes a method for balancing voltages on a first and a second DC conductor in a DC grid using a balancing circuit with a first and second semiconductor switch connected in series between the first and second DC conductors, and a connection to a ground potential that is arranged between the first and second semiconductor switches. In the presence of an asymmetry in the voltages of the first and second DC conductors to ground potential, a compensation current is generated between at least one of the DC conductors ground potential via at least one of the semiconductor switches, with the asymmetry in the voltages being reduced by the compensation current (IA), with the voltages of the DC conductors to ground potential being balanced.

Method for balancing voltages in a DC grid and balancing unit for a DC grid

The disclosure relates to an inverter including a first bridge branch with a first phase output, a second bridge branch with a second phase output, a third bridge branch with a third phase output, wherein the phase outputs of the bridge branches can each be connected to a phase conductor of a three-phase power distribution network. The inverter is configured, in a normal operating mode of the three-phase power distribution network and/or of a higher-level power supply network connected thereto, to connect the phase outputs to the relevant phase conductor and, in the event of a fault in the three-phase power distribution network and/or in the higher-level power supply network connected thereto, to disconnect the three-phase power distribution network from the higher-level power supply network via a network disconnector, to disconnect the first phase output from the first phase conductor by means of a switching unit and to connect same to a neutral conductor of the three-phase power distribution network, and to establish a neutral potential for the neutral conductor via the first bridge branch. The disclosure further relates to a method for operating an inverter of this kind.

3-phase PV inverter with 2-phase isolated operation in the event of a network fault

An inverter includes a DC/AC converter connectable to a DC power grid, at least one DC/DC converter arranged upstream of the DC/AC converter and providing a galvanic isolation, and a DC voltage link at the input of the at least one DC/DC converter and connectable to at least one DC power source. The inverter also includes at least one further DC voltage link which is galvanically isolated from the first DC voltage link by the DC/DC converter, on-board voltage rails supplying a controller and other auxiliary devices of the inverter with electric energy; and an on-board supply unit. The on-board supply unit is configured and adapted to feed the electric energy into the on-board voltage rails both out of the first DC voltage link and out of the at least one further DC voltage link.

Growing community of inventors

Kassel, Germany

Burkard Müller