Patent application number | Description | Published |
20090279328 | HVDC SYSTEM AND METHOD TO CONTROL A VOLTAGE SOURCE CONVERTER IN A HVDC SYSTEM - A method to control a voltage source converter in a HVDC system includes controlling a frequency and a voltage amplitude of an AC voltage generated by the voltage source converter independently of the conditions in an AC network connected to the voltage source converter. The method is performed by a control unit of an HVDC system. The method may form a basis of a method to black start an AC network. The AC network includes transmission lines and is connected to at least two AC power stations. One of the at least two AC power stations is connected via a HVDC system to the AC network. | 11-12-2009 |
20100085783 | METHOD AND SYSTEM TO INFLUENCE THE POWER GENERATION OF AN ADJUSTABLE SPEED GENERATOR - A method and a system to influence the power generation of at least one adjustable speed generator. The system includes a first voltage source converter connected to a local AC bus. The local AC bus is provided with power by the at least one adjustable speed generator. A second voltage source converter connected to an AC grid. A DC link is connected between the first and the second voltage source converter. At least one control unit controls the first and the second voltage source converters. The at least one control unit performs the method to control the AC voltage in the local AC bus via the first voltage source converter and to modify a reference value for the AC voltage magnitude of the local AC bus in dependence on the AC voltage magnitude of the AC grid. | 04-08-2010 |
20130063989 | INTERFACE ARRANGEMENT BETWEEN AC AND DC SYSTEMS USING GROUNDING SWITCH - An interface arrangement for connection between an AC system and a DC system and to a method of disconnecting a DC system from an AC system are disclosed. The arrangement includes a converter for conversion between AC and DC having a DC side for connection to the DC system and an AC side for being coupled to the AC system, a set of circuit breakers coupled between the AC side of the converter and the AC system and a breaker assisting unit including a set of branches connected between the AC side of the converter and ground, where each branch includes a switch in series with an impedance element. | 03-14-2013 |
20130070491 | INTERFACE ARRANGEMENT BETWEEN AC AND DC SYSTEMS INCLUDING FILTER AT TRANSFORMER NEUTRAL POINT - An interface arrangement is provided for coupling between an AC system and a DC system. The arrangement includes a converter for conversion between AC and DC and having a DC side and an AC side, a transformer having a primary side with primary windings for coupling to the AC system and a secondary side with secondary windings coupled to the converter, where the secondary windings are coupled to ground via a neutral point of the secondary side, and a filter with filter elements set for removing a frequency component of at three times the fundamental frequency of an AC voltage appearing on the AC side of the converter. The filter is connected between the neutral point of the secondary side of the transformer and ground. | 03-21-2013 |
20130088906 | Precision Switching For Carrier Based PWM - A voltage source converter station including a multilevel voltage source converter, for conversion of electrical power between AC and DC, and a control system. The voltage source converter includes a plurality of switching cells including switchable semiconductors, and the control system includes at least one main control unit for providing a voltage reference signal and a plurality of cell control units. Each cell control unit uses carrier based pulse width modulation for controlling the switching of a respective cell, where the main control unit is communicatively connected to the cell control units and provides the reference voltage signal to each cell control unit and each cell control unit creates a switching signal to each respective switching cell using the reference voltage signal and a carrier signal to effectuate the conversion. | 04-11-2013 |
20130200859 | CAPACITOR DISCHARGE IN A CELL BASED VOLTAGE SOURCE CONVERTER - A method and a device to discharge cell capacitors in a cell based voltage source converter. Each cell has switching elements in half bridge or full bridge configuration and a capacitor in parallel to the half or full bridge. Each cell has two terminals, whereof at least one is between two switching elements. The converter has AC and DC terminals, with the possibility to connect each of the terminals to ground, via a further switching element. A resistor is implemented into at least one of the ground connections. To discharge to capacitors, the switching elements in the respective cells are configured such, that the capacitor is in parallel connection to the terminals. The capacitors are thus discharged via the resistor to ground. | 08-08-2013 |
20130301313 | HVDC SYSTEM AND METHOD TO CONTROL A VOLTAGE SOURCE CONVERTER IN A HVDC SYSTEM - A method to control a voltage source converter (CON | 11-14-2013 |
20140191507 | METHOD FOR CONTROLLING POWER FLOW WITHIN A WIND PARK SYSTEM, CONTROLLER, COMPUTER PROGRAM AND COMPUTER PROGRAM PRODUCTS - The invention relates to a method for controlling power flow within a wind park system ( | 07-10-2014 |
20140268942 | INTERFACE ARRANGEMENT BETWEEN AC AND DC SYSTEMS FOR RELIABLE OPENING OF THE CIRCUIT BREAKER IN TIME - An interface arrangement for coupling between an AC system and a DC system. The arrangement includes a converter for conversion between AC and DC and having a DC side with a first and a second terminal for connection to the DC system and an AC side with a group of terminals for being coupled to the AC system, a transformer having a primary side with a first set of primary windings for being coupled to the AC system and a secondary side with a second set of secondary windings coupled to the converter, where the transformer is equipped with a third set of auxiliary windings and a short-circuiting device is connected between the third set of auxiliary windings and ground. | 09-18-2014 |