Danfoss A/s

Vestas Wind Systems A/s

Danfoss Micro Channel Heat Exchanger (jiaxing) Co., Ltd.

Lars Finn Sloth Larsen

Claus Thybo

Jan Prins

Honglian Thybo

Fabio Caponetti

Kenneth Bank Madsen

Thomas Scheel

Roozbeh Izadi-Zamanabadi

Martin Atzler

Martin Ansbjerg Kjær

Keld Hammerum

Robert Bowyer

Poul Brandt Christensen

Ian Couchman

Thomas Krüger

Eik Herbsleb

Leo Bram

Jes V Vogler

Torben Green

Asbjoern Leth Vonsild

Jakob Spangberg

Elk Herbsleb

Gunda Mader

Jesper Hoeyer

Fabiano Daher Adegas

Ejnar Luckmann

Asbjorn Leth Vonsild

Hans Moos

Roozbeh Izadi-Zamanabad

Jesper Hoyer

A method for controlling a vapour compression system () is disclosed. The vapour compression system () includes an ejector (), and has a non-return valve () arranged in the refrigerant path between an outlet () of an evaporator () and an inlet () of a compressor unit (), in such a manner that a refrigerant flow from the outlet () of the evaporator () towards the inlet () of the compressor unit () is allowed, while a fluid flow from the inlet () of the compressor unit () towards the outlet () of the evaporator () is prevented. A pressure, P, of refrigerant leaving the evaporator () is measured and a value being representative for a pressure, P, of refrigerant entering the compressor unit () is obtained. The pressures, Pand P, are compared to respective reference pressure values, Pand P. In the case that ε>ε, where ε=P−Pand ε=P−P, the compressor unit () is controlled based on P, and in the case that ε>ε, the compressor unit () is controlled based on P.

Method for controlling suction pressure of a vapour compression system

A method for controlling a vapour compression system () including a compressor unit () including one or more compressors (), a heat rejecting heat exchanger (), a receiver (), an expansion device () and an evaporator () arranged in a refrigerant path. A pressure value indicating a pressure prevailing inside the receiver () is obtained, and the obtained pressure value is compared to a first threshold pressure value. In the case that the obtained pressure value is below the first threshold pressure value, the compressor(s) () of the compressor unit () are controlled in order to reduce a suction pressure of the vapour compression system ().

Method for controlling a vapour compression system at a reduced suction pressure

A method for controlling a vapour compression system () including a compressor unit () including at least two compressors (), a heat rejecting heat exchanger (), a receiver (), an expansion device () and an evaporator () arranged in a refrigerant path is disclosed. At least one of the compressors is a main compressor () being fluidly connected to an outlet of the evaporator () and at least one of the compressors is a receiver compressor () being fluidly connected to a gaseous outlet () of the receiver (). A flow of vapour entering the receiver (), such as a mass flow of vapour entering the receiver () is estimated and compared to a first threshold value. In the case that the estimated flow is above the first threshold value, a pressure prevailing inside the receiver () is controlled by operating the receiver compressor ().

Method for controlling a vapour compression system based on estimated flow

A method for controlling ejector capacity in a vapour compression system () is disclosed. A parameter value being representative for a flow rate of liquid refrigerant from the evaporator(s) () and into a return pipe () is obtained, and the capacity of the ejector(s) () is adjusted based on the obtained parameter value. Ejector capacity may be shifted between low pressure ejectors (liquid ejectors) () and high pressure ejectors (gas ejectors) ().

Method for controlling ejector capacity in a vapour compression system

A method for estimating a wind speed at a wind turbine is disclosed, said wind turbine comprising a rotor carrying a set of wind turbine blades, each wind turbine blade having a variable pitch angle. A blade torsion contribution, representing torsion introduced in the wind turbine blades, is derived, based on an obtained rotational speed, &#x3c9;, of the rotor, and an obtaining a pitch angle, &#x3b8;, of the wind turbine blades. An adjusted pitch angle, &#x3b8;', is calculated as a sum of the obtained pitch angle, &#x3b8;, and the derived blade torsion contribution, and a wind speed, v, is estimated, based on the obtained rotational speed, &#x3c9;, and the calculated adjusted pitch angle, &#x3b8;&#x2032;. An accurate and reliable estimate for the wind speed is thereby obtained. The wind turbine may be controlled in accordance with the estimated wind speed, v.

Operating a wind turbine using estimated wind speed while accounting for blade torsion

A method for controlling suction pressure in a vapour compression system including one or more cooling entities is disclosed. For each cooling entity, a maximum required suction pressure and/or a required change in suction pressure for maintaining a target temperature in the refrigerated volume is obtained. A most loaded cooling entity among the one or more cooling entities is identified, based on the maximum required suction pressures and/or the required changes in suction pressure. The suction pressure of the vapour compression system is controlled in accordance with the maximum required suction pressure and/or required change in suction pressure for the identified most loaded cooling entity.

Method for controlling suction pressure based on a most loaded cooling entity

A fast-converging and reliable method for estimating a wind speed at, for example, a wind turbine comprising a rotor carrying a set of variable pitch angle wind turbine blades. The estimated wind speed is iteratively derived using a wind turbine rotor rotational speed, a turbine blade pitch angle, and a derived initial estimated wind speed. The initial estimated wind speed is based on the rotational speed and an initial tip speed ratio. The initial tip speed ratio is selected to be a value greater than a minimum tip speed ratio, wherein the minimum tip speed ratio defines a control region stability limit as a function of the pitch angle. Thus, for a given pitch angle, a minimum tip speed ratio is derived as a limit or boundary point between a stable control region and an unstable control region.

Method for estimating a wind speed at a wind turbine

The present invention relates to a method for operating a wind power plant in a wake situation, said wind power plant being connected to a power grid, the method comprising the steps of operating the wind power plant in a predetermined power mode of operation, terminating said predetermined power mode of operation, and increasing power generation of the wind power plant to a power level that exceeds an optimized wake power level of the wind power plant, and injecting the increased amount of power into the power grid as a power boost. Thus, the present invention is capable of generating a power boost to an associated power grid, said power boost exceeding the power level normally being available in a wake situation. The present invention further relates to a system for carrying out the method.

Active power boost during wake situation

The invention relates to a controller configured to determine one or more future values of blade control references and/or a generator control references for a wind turbine generator. The first of the future values of the control references are used for control purposes. The future control references are determined from a physical model of a system of the wind turbine generator by solving an optimization problem which includes at least one cost function and at least one constraint.

Model based controller for a wind turbine generator

The preset invention relates to wind turbines and, in particular inclining a wind turbine from the vertical position. A tower () of a wind turbine may be inclined from the vertical position in order to reduce the loads on the tower ().

Tilting wind turbine

A method for controlling a supply of refrigerant to an evaporator () of a vapor compression system (), such as a refrigeration system, an air condition system or a heat pump, is disclosed. The vapor compression system () comprises an evaporator (), a compressor (), a condenser () and an expansion device () arranged in a refrigerant circuit. The method comprises the steps of: Actuating a component, such as an expansion valve (), a fan or a compressor (), of the vapor compression system () in such a manner that a dry zone in the evaporator () is changed; measuring a temperature signal representing a temperature of refrigerant leaving the evaporator (); analyzing the measured temperature signal, e.g. including deriving a rate of change signal; determining a temperature value where a gain of a transfer function between the actuated component and the measured temperature drops from a maximum value to a minimum value, in a decreasing temperature direction; defining the determined temperature value as corresponding to a zero superheat (SH=0) value of refrigerant leaving the evaporator (), and controlling a supply of refrigerant to the evaporator () in accordance with the defined SH=0 temperature value, and on the basis of the measured temperature signal. The method steps may be repeated at certain time intervals in order to provide updated determinations of the SH=0 temperature value. The method allows the SH=0 point to be determined purely on the basis of the measured temperature signal. Subsequently, the supply of refrigerant to the evaporator () can be controlled purely on the basis of the measured temperature signal.

Method for controlling a supply of refrigerant to an evaporator

A method for determining wire connections in a vapor compression system () is disclosed. The vapor compression system comprises a compressor, a condenser, an expansion device () and an evaporator () being fluidly interconnected in a refrigerant path, and two or more sensor devices () arranged for measuring variables which are relevant for the operation of the vapor compression system (). The method comprises the steps of changing an operational setting, e.g. an opening degree of the expansion device () for the vapor compression system (), monitoring variable values, such as temperatures, being measured by at least two sensor devices (), e.g. arranged at various positions of the vapor compression system (), in response to said changed operational setting, comparing the measured variable values to expected behavior of at least one variable measured by a sensor device () in response to said changed operational setting, and based on the comparing step, determining at least one wire connection of the vapour compression system (). The method allows correct wire connections to be established without any special effort from the installing personnel, and without requiring rewiring of the system.

Method for determining wire connections in a vapour compression system

A refrigeration system includes an expansion valve and a compressor, the expansion valve, the evaporator and the compressor being arranged in a refrigerant flow path having refrigerant flowing therein. A method for controlling a flow of refrigerant to an evaporator includes steps of increasing an opening degree of the expansion valve, thereby increasing a flow of refrigerant to the evaporator sufficiently to substantially eliminate a dry zone of the evaporator, decreasing the opening degree of the expansion valve, and repeating the steps of increasing and decreasing. This causes the superheat value of refrigerant leaving the evaporator to 'toggle' between a zero level and a low, but positive, level. Thereby the refrigeration capacity is utilized more efficiently. Additionally, sufficiently low amount of liquid refrigerant is allowed to pass through the evaporator to prevent damage to the compressor.

Method for controlling a flow of refrigerant to an evaporator

A method of estimating a floor temperature of a solid floor that has a fluid conduit embedded in the floor. Provided is a control scheme that provides a sequence, where the concrete temperature can be estimated through the temperature of the fluid in the conduit embedded in the floor. After the concrete temperature is obtained, a heating sequence can be initiated for providing fast and accurate control of the floor temperature.

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Sydals, Denmark

Lars Finn Sloth Larsen