Dr. Johannes Heidenhain Gmbh

Markus Schoenlinner

Christian Von Le Suire

Norbert Huber

Michael Wichmann

A circuit arrangement is configured to supply an electromagnetic holding brake of an electric motor with an operating voltage for releasing the holding brake, and a voltage that is reduced relative to the operating voltage for holding the holding brake in the released position. The operating voltage is supplied from a higher-level control system disposed separately from the motor and the holding brake. The circuit arrangement is disposed in or on the motor or in or on the holding brake and includes a voltage regulator adapted to regulate, independently of the operating voltage, the reduced voltage to a fixed value after the holding brake is released.

Circuit arrangement for an electromagnetic holding brake

An inverter for the selective feeding of effective power and reactive power into a power grid has two serially connected intermediate circuit capacitors, the joint connection of which defines a median voltage level between a positive voltage level and a negative voltage level. It also has first, second, third, and fourth semiconductor switches having free-wheeling diodes respectively connected in parallel, which are arranged serially in this sequence between the positive and the negative voltage levels, the joint connection of the second and third semiconductor switches being connected to the power grid via a choke. The inverter also has serially connected first and second diodes, the joint connection of which is at the median voltage level, and whose second connection is connected to the joint connection of the first and second semiconductor switches and of the third and fourth semiconductor switches. Joint connections of two of the first to fourth semiconductor switches are connected to additional chokes, which by additional semiconductor switches form switchable paths for accepting free-wheeling currents. In this manner, it is possible to avoid putting stress on diodes as a result of the reverse recovery effect.

Inverter

In an inverter and a method for operating an inverter, the inverter includes a step-up converter circuit, a dynamic intermediate circuit, and a step-down converter circuit for converting a direct voltage of a direct voltage generator or string into an alternating voltage for supplying a network. The step-up converter circuit increases the direct voltage if the latter is lower than a peak-to-peak maximum of the network voltage, and the step-down converter circuit lowers a dynamic intermediate circuit voltage, as needed, to a lower voltage currently required in the network. The step-up converter circuit dynamically increases the direct voltage to the value currently required in the network and in the process temporarily supplies an approximately sinusoidal voltage curve for the intermediate circuit voltage.

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Tittmoning, Germany

Markus Schoenlinner