Siemens Aktiengesellschaft

Converteam Gmbh

Converteam Technology Ltd.

Converteam UK Ltd.

Ge Energy Power Conversion Technology Gmbh

Rodney Jones

Paul Brian Brogan

Henrik Stiesdal

Robert Vernon Fulcher

Erik Grøndahl

Paul Godridge

Jan Sundvall

Christopher Newton

Philip Perry Waite

Peter Menke

Eric Anthony Lewis

Rainer Zurowski

Joseph Hartley

Fan Yue

Erik Grondahl

A self-commutated converter is connected to further self-commutated converters by its AC voltage connection via an inductive component using a coupling point, which is common to all the converters, in an AC voltage network. An active power P and a frequency fare determined from a network voltageat the coupling point and a converter currentflowing via the inductive component. An active power difference value &#x394;P is supplied to an orthogonal controller and to a parallel controller. The output value from the parallel controller is used to minimize the reactive power exchanged between converter and coupling point. The frequency difference value &#x394;f is supplied to a frequency controller and the output value from the frequency controller is logically combined with the output value from the orthogonal controller and the output value from the parallel controller, the frequency difference value &#x394;f being simultaneously minimized.

Control method for self-commutated converter for controlling power exchange

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 controller is provided for controlling a power converter that converts electrical input power of a wind turbine into electrical output power provided to a grid. The power converter includes grid-side and turbine-side converter parts. The controller comprises an input terminal for receiving a voltage reference signal associated with a predefined grid voltage and a frequency reference signal associated with a predefined grid frequency, and a network bridge controller adapted to control power conversion of the grid-side converter part. The network bridge controller includes a modulator for modulating gate drive command signals in the grid-side converter part based on a reference voltage and a reference angle derived from the voltage reference signal and the frequency reference signal. The modulator is adapted to modulate the gate drive command signals to maintain the predefined grid voltage and the predefined grid frequency in the power converter in case of failure within the grid.

Controller for controlling a power converter

An AC-to-AC-converter for converting a first frequency AC-voltage to a second frequency AC-voltage is disclosed. The converter includes: a first converter section which includes a first input terminal, a second input terminal, a first DC-output node, and a second DC-output node; a second converter section which includes a first DC-input node connected to the first DC-output node, a second DC-input node connected to the second DC-output node, and at least two second output terminals; a DC-link overvoltage clamp which is coupled between the first DC-output node and the second DC-output node; and a capacitor system. The first converter section, the second converter section, the DC-link overvoltage clamp, and the capacitor system are integrated into one assembly.

AC-to-AC converter and method for converting a first frequency AC-voltage to a second frequency AC-voltage

A circuit for protecting a controllable power switch is provided. The controllable power switch has a first power switch terminal connected to a first terminal, a second power switch terminal connected to a second terminal, and a power switch control terminal. Further, the circuit includes a diode with a first diode terminal and a second diode terminal, and a controllable control switch having a first control switch terminal connected to the first diode terminal, a second control switch terminal, and a control switch control terminal. A signal applied to the power switch control terminal is based on a signal at the second control switch terminal. Further a method for protecting a controllable power switch is described.

Circuit and method for protecting a controllable power switch

A current controller device using a vector control algorithm for controlling conversion of DC power into AC power is provided. The controller device has an open loop control loop gain and produces a first and a second voltage demand signals based on a first and a second current demand signals, a first and a second current feedback signals, a first and a second voltage feedback signals. The open loop control loop gain depends on frequencies of the first and second current feedback signals. A first and a second filters are provided at a first and a second current feedback inputs respectively. The first and second filters each have a filter characteristics to reduce the frequencies of the first and second current feedback signals at which the open loop control loop gain is greater than unity and has a phase less than or equal to minus 180&#xb0;.

Current controller device and vector control method for controlling power conversion

A method of operating an inverter for converting a DC power into AC power by use of a pulse width modulation switching scheme is provided is disclosed. The inverter is controlled by use of the pulse width modulation switching scheme to provide an alternating current based on a current demand signal defining an alternating current provided by the inverter. An upper current threshold and a lower current threshold are provided. An instantaneous value of the alternating current is measured. When the instantaneous value of the alternating current overshoots the upper current threshold or undershoots the lower current threshold, the pulse width modulation switching scheme is replaced by an amended switching scheme which controls the instantaneous value of the alternating current to be between the upper current threshold and the lower current threshold. The upper current threshold and the lower current threshold oscillate with at least one alternating phase.

Method of operating an inverter and inverter control arrangement

A saturation control unit for an interphase transforming unit is provided. The interphase transforming unit has a primary coil and a secondary coil which are magnetically coupled via a magnetic core member. The saturation control unit includes a minimum detecting unit and a maximum detecting unit. The minimum detecting unit detects a minimum value of a magnetizing current of the interphase transforming. The maximum detecting unit detects a maximum value of the magnetizing current. A saturation estimating unit is provided for estimating an offset value of the magnetizing current. A saturation control signal generating unit is provided for generating a saturation control signal for the interphase transforming unit based on the detected minimum value, the detected maximum value, and the estimated offset value.

Saturation control unit for an interphase transforming unit and PWM control apparatus for a voltage converting device

A method of adapting a configuration of a voltage converting device is provided. The voltage converting device includes a plurality of voltage converting units in parallel electrical connection to one another, and a plurality of inter-bridge transforming units. Each of the inter-bridge transforming units has a primary coil and a secondary coil. Each of the voltage converting units is electrically connected to a primary coil of a different one of the inter-bridge transforming units. The method includes detecting a status of at least one element of the group consisting of the voltage converting units and the inter-bridge transforming units. The method further includes adapting an activity state of the element based on the detected status of the element by moving the element from a first position to a second position.

Method of adapting a configuration of a voltage converting device and voltage converting unit for a voltage converting device

A circuit for regulating a DC voltage is provided. The circuit includes: a controllable switch system, a resistor, a first control circuit and a second control circuit. The controllable switch system includes a first terminal, a second terminal, a first control terminal, and a second control terminal. The controllable switch system is configured to establish an electrical connection between the first terminal and the second terminal, if a first control signal applied to the first control terminal satisfies a first criterion or if a second control signal applied to the second control terminal satisfies a second criterion; A method for regulating a DC voltage and an AC-to-AC-converter are described.

Circuit and method for regulating a DC voltage applied between a first and second DC voltage terminal

A power converter that interfaces a motor requiring variable voltage/frequency to a supply network providing a nominally fixed voltage/frequency includes a first rectifier/inverter connected to a stator and a second rectifier/inverter. Both rectifier/inverters are interconnected by a dc link and include switching devices. A filter is connected between the second rectifier/inverter and the network. A first controller for the first rectifier/inverter uses a dc link voltage demand signal indicative of a desired dc link voltage to control the switching devices of the first rectifier/inverter. A second controller for the second rectifier/inverter uses a power demand signal indicative of the level of power to be transferred to the dc link from the network through the second rectifier/inverter, and a voltage demand signal indicative of the voltage to be achieved at network terminals of the filter to control the switching devices of the second rectifier/inverter.

Power converters

Each voltage converting unit outputs a first signal at a first output and second signal at a second output. Each first transforming unit includes a magnetically coupled primary and secondary coil, the first output of each one of the converting units is connected to a primary coil of a different one of the first transforming units, the primary coil of each one of the first transforming units is electrically connected to one secondary coil of another one of the first transforming units. Each second transforming units includes a magnetically coupled primary and a secondary coil, the second output of each one of the voltage converting units is connected to a primary coil of a different one of the second transforming units, the primary coil of each one of the second transforming units is electrically connected to one secondary coil of another one of the second transforming units.

Power converting device and power supply apparatus

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.

Growing community of inventors

Stoke on Trent, United Kingdom

Rodney Jones