Abstract:
An interface arrangement is configured to couple an alternating current, AC, power system with a direct current, DC, power system, or vice versa. The interface arrangement includes a plurality of series-connected converter modules. Each converter module includes at least one multi-level converter cell configured to provide a voltage contribution to at least a portion of an AC waveform for example based on voltage of the DC power system. Each converter module includes at least one converter valve, electrically connected to the multi-level converter cells and including at least two anti-parallel thyristors. The converter valves are switchable between conducting states with a selected current conduction direction and a non-conducting state so as to selectively control polarity of any voltage contribution provided by the at least one multi-level converter cell. The converter valves can also serve as fault protection, e.g. to divert overcurrents.
Abstract:
A subsea unit includes a housing containing a dielectric liquid, a first heat generating component and a second heat generating component. The first heat generating component is arranged in thermal connection with the housing and the second heat generating component is arranged at a distance from the housing. A method of cooling heat generating components contained in a housing of a subsea unit is also presented.
Abstract:
A pressure plate for a friction coupling such as a clutch or brake system is disclosed in the present application. The pressure plate includes one or more pockets with a phase change material disposed therein. The phase change material operates to absorb and release heat when the friction coupling cycles between activation and deactivation so as to minimize a maximum temperature of the pressure plate.
Abstract:
The present invention provides a system and method for advising wireless computer networks on inter-network interferences during their life time. The method of the present invention initially observes initial channel utilization profiles along with corresponding time-slots of dynamic network elements and network characteristics of a first network and stores as historical channel utilization profiles. The initial transmission profiles an interfering second network are also recorded. The threshold transmission profiles are then recorded as historical transmission profiles. The aggregator determines interference patterns, by comparing historical channel utilization profiles with runtime threshold transmission profiles and advises and pre-warns appropriate network actions to a network manager of the first network on the interference prone zones. The system of the present invention includes a first network with a common multi-network interference observer, to advise on inter-network interferences.
Abstract:
A multilevel converter converting between AC and DC includes a phase arm with a number of cells between a DC pole and an AC terminal, the cells include at least one hybrid full bridge cell including a first cell connection terminal for coupling to the DC pole, a second cell connection terminal for coupling to the AC terminal, an energy storage element having a positive and a negative end, a first group of series connected semiconducting units in parallel with the energy storage element, where a junction between these forms one cell connection terminal, and a second group of series connected semiconducting units in parallel with the energy storage element and including a third semiconducting unit and a fourth semiconducting unit consisting of a number of unidirectional conducting elements including at least one unidirectional conducting element, where a junction between these forms a further cell connection terminal.
Abstract:
A simulation system to determine an optimal trajectory path for a robot with an attached implement includes a trajectory simulator which provides a simulated trajectory path for an implement, an implement model database which comprises motion data of the implement, and a logger that associates a time stamp of the implement's motion during the simulated trajectory path to generate logger data. A profile is determined by the logger data received from the logger which identifies implement motion that exceeds predetermined thresholds, and a tuner adjusts the simulated trajectory path so as to reduce the number of times predetermined thresholds are exceeded.
Abstract:
A unique electrical system includes a first electrical component and a second electrical component. A conductor electrically couples the first electrical component with the second electrical component. A sensor is constructed to sense an AC power flow in the conductor and output an AC signal proportional to the AC power flow. A band-pass filter is in electrical communication with the sensor and constructed to receive and filter the AC signal and to generate an AC voltage proportional on the AC signal. A controller is in electrical communication with the band-pass filter, and is operative to receive and sample the AC voltage. The controller is configured to execute program instructions to sum sequential AC voltage values received from the band-pass filter over a sample time period, and to determine whether an arc fault has occurred based on the summed AC voltage values.
Abstract:
A synchronous machine system comprising a synchronous motor including a stator, stator winding, rotor, and field winding; an AC power supply circuit structured to transmit current to or from the stator winding of the synchronous motor at a controlled frequency and transmit current to or from a power source at a controlled frequency; a DC exciter unit structured to receive power from a power source, convert the received power to DC power at a desired voltage, and supply the converted power across a DC bus to the field winding of the synchronous motor; and an energy storage circuit coupled to the DC bus of the DC exciter unit having at least one ultracapacitor, and structured to receive power from a power source, to charge the ultracapacitor, and to provide power to the field winding of the synchronous motor following a power failure.
Abstract:
One exemplary embodiment is method of operating an electrically excited synchronous machine (EESM) system. The system includes a converter operatively coupled with one or more stator windings, an exciter operatively coupled with one or more field windings, a controller operatively coupled with the converter and the exciter, and a power supply operatively coupled with the converter and the exciter. The controller determines whether a power supply fault condition exists and whether EESM system is operating in a motor mode or a generator mode. If the power supply fault condition exists and the EESM system is operating in the motor mode, entering one of a motor ride through control mode and a motor controlled braking control mode If the power supply fault condition exists and the EESM system is operating in the generator mode, entering one of a generator ride through control mode and a generator controlled braking control mode.
Abstract:
An arrangement for tapping power from a DC power line to an AC power line includes power transfer modules between two DC potentials, each including a first branch with a string of converter cells in parallel with a second branch including a capacitor and being connected to an AC phase. There is at least one control unit that controls the arrangement considering one or more of a) distributing appropriate AC and DC voltages in converter output voltages of all series connected modules, b) maintaining/setting cell capacitor voltages in specific range and allowing boost mode operation, c) performing possible balancing of the introduced capacitor and d) employing an alternate approach of using passive filters to mitigate low order harmonics.