Patent application number | Description | Published |
20090284876 | Electric Power Converter - A voltage source converter including a string of series connected active semiconducting elements. The converter includes in case of an active semiconducting element failure a calculation element configured to calculate an operation dc voltage including a sum of dc ratings of each remaining active semiconducting element in the string, and a regulator configured to regulate the converter to assume the operation dc voltage over the converter. | 11-19-2009 |
20120063181 | Modular Voltage Source Converter - Voltage source converter based on a chain-link cell topology including one or more phases, each of the phases having one or more series-connected chain-link cell modules connected to each other. The output voltage of the voltage source converter is controlled by control signals applied to the series-connected chain-link cell modules. In case of failure of a chain-link cell module, that module is controlled, by the control signals, such that zero output voltage is provided at its output voltage AC terminal. | 03-15-2012 |
20120069612 | ARRANGEMENT FOR EXCHANGING POWER - An arrangement for exchanging power with a three-phase electric power network includes a Voltage Source Converter having three phase legs with each a series connection of switching cells. The three phase legs are interconnected in a neutral point by forming a wye-connection. The arrangement also includes a device connected to the neutral point of the converter and configured to provide a current path for a zero-sequence current. A control unit is configured to calculate a value for amplitude and phase position for a zero-sequence current for which, when added to said three phase legs upon generation of a negative-sequence current, the resulting energy stored in energy storing capacitors in each phase leg will be constant and to control semiconductor devices of said switching cells to add such a zero-sequence current to the currents of each phase leg of the converter. | 03-22-2012 |
20120081939 | Arrangement For Exchanging Power - An arrangement for exchanging power, in shunt connection, with a three-phase electric power network includes a Voltage Source Converter having at least three phase legs with each a series connection of switching cells. Each switching cell has at least two semiconductor assemblies connected in series and having each a semiconductor device of turn-off- type and a rectifying element connected in anti-parallel therewith and at least one energy storing capacitor. A control unit is configured to control the semiconductor devices of each switching cell and to deliver a voltage across the terminals thereof being zero or U, in which U is the voltage across the capacitor. The control unit is also configured to calculate a value for amplitude and phase position for a second negative sequence-current or a zero-sequence voltage or a value of a dc current. | 04-05-2012 |
20120086412 | Arrangement For Exchanging Power - Power exchanging arrangement, in shunt connection, with a three-phase electric power network including on one hand for each said phase a reactive impedance element and a Voltage Source Converter connected in series with said element, and on the other hand a control unit configured to control semiconductor devices of turn-off type of said converter for generating a voltage with a fundamental frequency being equal to the fundamental frequency of the voltage of the respective said phase and by that control a flow of reactive power between said arrangement and the respective phase of said electric power network. Each Voltage Source Converter includes a series connection of switching cells in the form of so-called H-bridges including two switching elements connected in parallel and each having at least two semiconductor assemblies connected in series. Each switching cell further comprises at least one energy storing capacitor connected in parallel with said switching elements. | 04-12-2012 |
20120092906 | ARRANGEMENT FOR EXCHANGING POWER - An arrangement for exchanging power with a three-phase electric power network comprises a Voltage Source Converter having three phase legs with each a series connection of switching cells. The three phase legs are interconnected by forming a delta-connection. The arrangement also includes a control unit configured to calculate a value for amplitude and phase position for a zero-sequence current for which, when circulated in the delta-connection circuit of the three phase legs, the balance of the total direct voltage of each of the three phase legs with respect to the other two phase legs is restored will there be an unbalance and control the semiconductor devices of switching cells of the phase legs to add such a zero-sequence current to the currents of each phase leg of the converter. | 04-19-2012 |
20120155130 | CONVERTER CELL MODULE, VOLTAGE SOURCE CONVERTER SYSTEM COMPRISING SUCH A MODULE AND A METHOD FOR CONTROLLING SUCH A SYSTEM - A converter cell module and a voltage source converter system. The converter cell module includes at least two switching elements, means for energy storage and an autotransformer. The autotransformer is arranged to bypass the converter cell module in the case of failure occurring in the converter cell module. | 06-21-2012 |
20140055116 | Method And Control Arrangement In A Power System - A method of controlling a magnitude of an electrical parameter in a power system via a high voltage electron tube. The method includes the steps of measuring the magnitude of the electrical parameter; generating a control signal based on the magnitude of the electrical parameter and on a reference magnitude of the electrical parameter; and switching the high voltage electron tube via the control signal such that the reference magnitude of the electrical parameter is essentially obtained. A control arrangement and a power system is also presented. | 02-27-2014 |
20140077767 | Methods For De-Energizing A Chain-Link Converter, Controller, Computer Programs And Computer Program Products - A method for de-energizing a chain-link converter including one or more phase legs each phase leg having a number of series-connected converter cells. The phase legs are connected to a respective charging resistor. The method includes the steps of: opening AC circuit breakers arranged between a power grid and the chain-link converter, opening charging resistors switches arranged in parallel with a respective one of charging resistors, and circulating a current within the chain-link converter through the charging resistors and each phase leg, whereby the DC capacitor are discharged. The invention also relates to a controller, computer program and computer program products. | 03-20-2014 |
20140084877 | Compensation System For Medium Or High Voltage Applications - A compensating system for a power system includes a compensator including semiconductor switch means, which compensator has phase legs which on a first side of the compensator defines AC inputs for connection to a respective phase of the power system. The phase legs are connected in wye connection at a second side of the compensator, which wye connection has a neutral point. A filter arrangement at a first side thereof is connected to the neutral point of the wye connection and at a second side is connected to the AC inputs to thereby form a circuit with the compensator. The filter arrangement is arranged such that the circuit acts essentially as an open circuit for positive sequence currents or voltages and negative sequence currents or voltages, and as a closed circuit for zero-sequence currents. | 03-27-2014 |
20140097804 | Method For Energizing A Chain-Link Converter, Controller, Computer Programs And Computer Program Products - A method in a controller for energizing a chain-link converter including one or more phase legs, each phase leg including a number of series-connected converter cells, each converter cell including four valves arranged in an H-bridge connection with a DC capacitor. Each valve in turn includes a semiconductor switch in parallel with a diode. The method includes the steps of: charging the DC capacitor of each converter cell to a voltage level at which the semiconductor switches are controllable but below their nominal voltage; diagnosing the converter cells so as to detect failed components thereof; bypassing faulty components in a controlled manner; charging the DC capacitors to their nominal voltage. The invention also relates to a controller, computer programs and computer program products. | 04-10-2014 |
20140112038 | Method And Controller For Protecting A Voltage Source Converter - A method in a controller for protection of a voltage source converter including one or more phases, each phase including one or more series-connected converter cells. Each converter cell has a by-pass switch for enabling by-pass thereof. The method includes the steps of detecting an over-voltage condition, and controlling simultaneously the by-pass switches of each converter cell, so as to bypass the converter cells upon detection of such over-voltage condition. The invention also encompasses a controller, computer programs and computer program products. | 04-24-2014 |
20140218986 | Multilevel Converter And A Method For Controlling Multilevel Converter Including Balancing Cell Voltages - A multilevel converter for controlling a multilevel converter is provided. The multilevel converter is a single phase converter with one phase leg, or a three phase converter with three phase legs, the phase legs of the three phase converter are interconnected in a star-configuration. The single phase converter with one phase leg, or each three phase converter with three phase legs, phase leg includes switching cells, and each switching cell includes semi-conductor switches arranged to selectively provide a connection to a corresponding energy storage element. The converter also includes a controller, which is provided to monitor the DC voltage of the energy storage elements, and the controller is provided to control the switching of each switching cell. The phase leg of the single phase converter, or each phase leg of the three phase converter, includes two parallel branches of switching cells, the branches being configured in a closed circuit. | 08-07-2014 |