Siemens Aktiengesellschaft

Unify Gmbh Co. Kg

Ruxandra Scheiterer

Dragan Obradovic

Chongning Na

Günter Steindl

Philipp Wolfrum

Per Egedal

Franz-Josef Götz

Björn Andresen

Andrei Szabo

Michael Bernhard Buhl

Guenter Steindl

A method for estimating grid properties of a power grid coupled to a generator at a point of common coupling is provided. First, a voltage Vat the point of common coupling is measured. Second, a current Iat the point of common coupling is measured. Third, the grid properties are estimated by a grid model using as input parameters the measured voltage Vat the point of common coupling, the measured current Iat the point of common coupling and the determined phase angle. Advantageously, the absolute phases of the voltage and the current at the point of common coupling are not necessary, which makes the present method less prone to errors due to measurement noise. Further, a device and a computer program product are provided.

Method and device for estimating grid properties of a power grid

A method for time synchronization in a communication network comprising a multiplicity of network nodes, wherein synchronization messages are transmitted in the communication network and the synchronization message received in a slave node contains synchronization information for synchronizing the slave time of the slave node with the master time, i.e., synchronization messages are transmitted in a closed ring or line topology and the slave node receives first and second synchronization messages from different transmission directions, and wherein the slave node synchronizes a first time with the synchronization message from one transmission direction and a second time with the synchronization message from the other transmission direction.

Method for time synchronization in a communication network

A method for synchronizing clocks in a communication network includes a first clock of a first network element which is a master element is used for synchronizing second clocks of one or more second network dements which are slave elements. A first sequence of first messages transmitted from the first network element to the second network element and/or a second sequence of second messages transmitted from the second network element to the first network element is recorded. First messages and/or second messages out of those sequences are identified by using an appropriate threshold function with respect to the transmission delays of those messages. Those identified messages have the same constant minimum delay, and based on those messages clock synchronization between the first clock and the second clock is performed.

Method for synchronizing clocks in a communication network

A method for time synchronization in a communications network having multiple nodes, wherein the nodes comprise a first node and at least one second node, where the first node generates first cycle counter states according to a reference clock frequency and the second node or nodes each generate second cycle counter states according to an internal clock frequency, where a time synchronization is carried out in sequential synchronization cycles, in which synchronization messages originating from the first node are sequentially transmitted from one node to another node, and a synchronization message transmitted by a node contains information used for time synchronization in the at least one second node receiving the synchronization message such that a time synchronization is performed in a given second node based on an estimation of a first cycle counter state and a compensation factor in combination with a linear quadratic regulator.

Method for time synchronization in a communications network

A system and method for time synchronization in a communication network. The communication network includes a plurality of network nodes each having a respective internal clock, and a reference node having a reference clock and each configured transmits synchronization messages within the communication network. At least one network node is configured to determine an estimated reference clock time discretely upon arrival of a synchronization message at the at least one network node. To that end, the at least one network node includes a controller for determining a controlled time comprising a time-continuous estimate of the discreetly estimated reference clock time. The controller is configured to determine the controlled time based on an input that is extrapolated to an execution time instant of the controller, where the execution time instant is separated from the time instant of arrival of the synchronization message by a delay (&#x394;t).

System and method for time synchronization in a communication network

The invention refers to a method for synchronizing clocks in a communication network, wherein a first clock of a first network element (MA) which is a master element is used for synchronizing second clocks of one or more second network elements which are slave elements. According to the method of the invention, a first sequence of first messages transmitted from the first network element to the second network element and/or a second sequence of second messages transmitted from the second network element to the first network element is recorded. First messages and/or second messages out of those sequences are identified by using an appropriate threshold function with respect to the transmission delays of those messages. Those identified messages have the same constant minimum delay, and based on those messages clock synchronization between the first clock and the second clock is performed. The invention has the advantage that clock synchronization is possible even if an intermediate switch causing an unknown delay is located in the transmission path between the first and the second network element. This is because most of the messages are transmitted within a minimum constant delay via such an intermediate switch and, by identifying those messages, a line delay between the first network element and second network element can be estimated and used for synchronizing the second clock with the first clock. The synchronization method of the invention is preferably used for synchronizing clocks in a DECT network. Furthermore, in a preferred embodiment, the first and second messages are messages according to the standard IEEE 1588.

A device and method for time synchronization in a communication network, wherein a virtual clock is produced by a controller in each network node based on the PROFINET-Standard and/or the Precision Transparent Clock Protocol. In contrast to known methods for estimating the time, the time of the virtual clock does not undergo sudden changes. The virtual clock includes a controlled, continuous path. As a result, the virtual clock is particularly suitable for time-critical applications. Here, the estimation of the time of a reference clock is improved by 18-35%. Accordingly, a markedly greater number of network nodes may be synchronized with a predetermined level of accuracy for the time synchronization.

Device and method for time synchronization in a communication network

There is described a method for transmitting synchronization messages in a communication network, the communication network comprising a plurality of network nodes communicating with one another, each containing an internal clock, which is timed with a node clock frequency assigned to the respective network node. The synchronization messages transmitted in the communication network serve to synchronize the times of the internal clocks of the network nodes and contain the pulse counter status of a synchronization clock operating at a predefined synchronization clock frequency. The pulse counter status is estimated by each network node and updated in the synchronization message. Changes in the synchronization clock frequency are taken into account when estimating the pulse counter status. Precise determination of the pulse counter status is achieved with the aid of an approximation of the change over time in the pulse ratio between synchronization clock frequency and node clock frequency by means of a function, with the result that the pulse ratio on transmission of a new synchronization message can be predicted and a precise current pulse counter status can be determined on the basis of the predicted pulse ratio. The method is particularly suitable for use in a communication network of an industrial automation system, whose components communicate with one another for example according to the Profinet standard.

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Geretsried, Germany

Ruxandra Scheiterer