Siemens Aktiengesellschaft

Siemens Gamesa Renewable Energy A/s

Ge Energy Power Conversion Technology Gmbh

Converteam Technology Ltd.

Converteam UK Ltd.

Siemens Gamesa Renewable Energy Gmbh & Co. Kg

Robert Vernon Fulcher

Henrik Stiesdal

Paul Brian Brogan

Rodney Jones

Eric Anthony Lewis

Paul Godridge

Thomas Dreyer

Joseph Hartley

Philip Perry Waite

Fan Yue

Jerome Koenig

Christoph Nentwig

Provided is a method of controlling wind turbine converters of wind turbines parallel connected at a point of common coupling, the method including: generating for each converter within a same length of a pulse width modulation period a pulse, wherein the pulses start for different converters at different pulse start phases, wherein pulse start phase differences of the pulse start phases between at least two of adjacent converters are unequal.

Selecting switching times of wind turbine converters

A method of controlling a power unit having a plurality of converter modules coupled in parallel, is configured to convert DC into AC voltages or AC into DC voltage. The method includes (a) receiving a control value for each phase of each converter module, (b) obtaining a set of phase current values for each converter module, (c) generating a compensation value for each phase of each converter module based on the set of phase current values and a set of stored data, the set of data representative of non-linearity characteristics of the converter modules as functions of phase current value, (d) generating a compensated control value for each phase of each converter module based on the corresponding control value and compensation value, and (e) supplying the compensated control values to the respective converter modules. A controller, power unit, wind turbine, computer program and computer program product are similarly configured.

Controlling parallel converter systems for wind turbines

A method of controlling a plurality of power convertersandcan be used to interface to a supply network, ac busbar etc. Each power converter includes a network bridgeoperating in accordance with a pulse width modulation (PWM) strategy having the same switching period and which causes at least one unwanted harmonic in the supply network voltage. The method includes the step of providing the switching period of the PWM strategy of each network bridge with a different time offset relative to a time datum such that the at least one unwanted harmonic in the supply network voltage is at least partially cancelled. Two alternative ways of providing the time offset are described.

Control methods for the synchronization and phase shift of the pulse width modulation (PWM) strategy of power converters

A control system for controlling conversion of an input power into an output power in a converter module is provided. The control system includes an input power terminal, an output power terminal, and an active switching device. The control system further includes a master controller and a communication link interconnecting the master controller and the converter module. Also, the system has a timing generator generating a timing signal with a cycle time equal to or less than the shortest time constant of the converter module and immediate power circuit elements relating to the converter module. The timing generator is integrated in or interconnected with the master controller. Furthermore, the control system has a signal generator integrated in or interconnected with the master controller generating switching control signals, each switching control signal containing a control message defining a switching state for the active switching device.

Method and control system for controlling power conversion in a power converter

A method of controlling a power converter is used to interface to a power grid or supply network operating at a frequency (Fnet) that is nominally fixed (say at 50 Hz, for example) but which can be varied as a way of controlling power imbalanced within the network as a whole. The power converter can include a network bridge that operates in accordance with the pulse width modulation (PWM) strategy having a switching frequency (Fpwm), a nominal switching frequency (Fpwm_nom) and a number of pulses per period (Pulse_Number). The method includes the step of varying the switching frequency (Fpwm) of the PWM strategy in accordance with the time-varying frequency (Fnet) of the supply network to achieve only integer odd harmonics of the time-varying frequency (Fnet) and the step of adjusting the number of pulses per period (Pulse_Number) in accordance with the time-varying frequency (Fnet) of the supply network to maintain a switching frequency (Fpwm) that is less than, or equal to, the nominal switching frequency (Fpwm_nom).

Control methods for pulse width modulation (PWM)

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Stoke on Trent, United Kingdom

Robert Vernon Fulcher