NORTHERN POWER SYSTEMS, INC. Patent applications |
Patent application number | Title | Published |
20120147637 | Methods, Systems, and Software for Controlling a Power Converter During Low (Zero)-Voltage Ride-Through Conditions - A power converter control system having a phase tracker that is designed and configured to estimate the phase of the voltage on the power network that will be on the network when network recovers from a fault on the network. Such a power converter control system allows a power-network-connected power source to ride-through a fault event and continue supplying power thereto at the designed phase and frequency. In one embodiment, the phase tracker provides this estimate by having a response time slow enough that the voltage drop or sag caused by the fault substantially does not affect the control system. In another embodiment, the phase detector is designed and configured to freeze the frequency of its output upon detection of a fault event on the power network. | 06-14-2012 |
20120146335 | Wind Power Unit Having an Underslung Transformer - A wind power unit that includes a tower and a support structure that cantilevers from the upper end of the tower. The wind power unit includes an electrical transformer that is suspended from the support structure. In one embodiment, the transformer extends through an opening in the bottom portion of a nacelle that encloses the support structure and includes electrical connections on its upper end that are accessible from inside the nacelle via a service opening in a floor located above the transformer. | 06-14-2012 |
20120146333 | Systems for Load Reduction in a Tower of an Idled Wind-Power Unit and Methods Thereof - Systems and methods for reducing dynamic loading in an idled wind power unit include sensing at least one parameter indicative of dynamic loading and executing a reduced torque brake mode, which may comprise a controlled brake and brake-release sequence, with the turbine braking system when the sensed parameter exceeds a selected value. The reduced torque brake mode absorbs energy and reduces dynamic loading thereby. | 06-14-2012 |
20120075051 | Magnetic Devices and Transformer Circuits Made Therewith - A magnetic device producing a small amount of leakage flux and capable of substantially eliminating the amount of leakage flux that escapes the magnetic core of the device. The device includes at least a portion of an electronic circuit that includes an interphase transformer arranged on a magnetic core. The reactor windings on each leg of the magnetic core are disposed in close proximity to each other and can be wound concentrically or in a bifilar fashion. The resulting combination of the magnetic core and windings provides a high degree of magnetic coupling between reactor windings disposed on the same leg and between reactor windings disposed on differing legs. The high degree of magnetic coupling substantially reduces the amount of leakage flux that can affect other metal objects proximate the magnetic device. | 03-29-2012 |
20120074798 | Electromagnetic Rotary Machines Having Modular Active-Coil Portions and Modules For Such Machines - Electromagnetic rotary machines, such as electrical power generators and electric motors, that have one or more active portions modularized into a set of modules. Each of the modules is secured to a support frame via a sliding-interlock system that allows that module to be slidingly engaged with the support frame. In some embodiments, each module can include an integrated coolant conduit that carries a coolant to cool the active portion during operation. The modules can each be self-contained in the respect that essentially all that needs to be done to form the active portion and corresponding portion of the cooling system is to install the modules and make any remaining electrical and coolant conduit connections. | 03-29-2012 |
20120074797 | Sectionalized Electromechanical Machines Having Low Torque Ripple and Low Cogging Torque Characteristics - A method and apparatus for reducing or eliminating the effects of torque ripple and cogging torque and otherwise improving performance in an electromechanical machine such as a motor or generator. The rotor and/or stator is conceptually sectionalized and the sections spaced apart by amount sufficient to alleviate deleterious aspects of cogging torque and torque ripple. Positioning of the stator teeth or rotor magnets is determined based on the calculated spacing. Conceptual sections may be formed as physically individual segments. Unwound teeth may be disposed in end spaces between sections occupying less than the entire area of the end space. | 03-29-2012 |
20120074709 | Method and Apparatus for Rotor Cooling in an Electromechanical Machine - An apparatus and method for cooling the rotor in an electromechanical machine such as a wind turbine generator is disclosed. Fluid cooling passages may be formed in the rotor, defined at least in part by a support member for magnets mounted on the rotor. Cooling fluid intake may be through the stator surrounding the rotor. | 03-29-2012 |
20120073134 | Method and System for Servicing a Horizontal-Axis Wind Power Unit - A method and system for attaching a service device to a wind turbine of a wind power unit, using the wind turbine to rotate the service device into one or more service positions, and using the service device to perform servicing on the wind power unit. In some embodiments, a blade of the wind turbine is removed and the service device is mounted in its place. In other embodiments, the service device is mounted to a device mount approximately in a saddle region between adjacent blades. In one example, the service device is a crane. In another example, the service device is a stator module installation/removal tool. | 03-29-2012 |
20120073118 | Module-Handling Tool for Installing/Removing Modules Into/From an Electromagnetic Rotary Machine Having a Modularized Active Portion - A module-handling tool for facilitating installation, servicing, and/or dismantling of a electromagnetic rotary machine, such as an electrical power generator or electric motor, having a modularized active portion. In one embodiment, module-handling tool is configured for a machine having a modularized stator having a number of removable modules. In one example of such stator-module-handling tool, the tool is designed and configured to hold a stator module and be temporarily secured to the rotor of the machine during the process of installing the stator module into the machine or removing the module from the machine. In this example, the module-handling tool also acts as a module carrier for transporting a module to or from the machine. | 03-29-2012 |
20120073117 | Method and System for Maintaining a Machine Having a Rotor and A Stator - Methods of precisely positioning a rotor of a machine into one or more service positions for the purpose of servicing the machine. In some embodiments, the machine includes A rotor and a stator segmented into multiple removable stator modules. During servicing, a stator-module replacement tool is precisely located in any one or more of multiple service positions corresponding to the multiple stator modules by selectively energizing the machine. In other embodiments, the machine includes a stator and a rotor having multiple removable permanent magnets corresponding respectively to multiple service positions. During servicing, the rotor is precisely located in any one or more of multiple service positions corresponding to the permanent magnets by selectively energizing the machine. A servicing control system is disclosed for controlling the excitation of a machine stator in a manner that effects precise positioning of the rotor into a selected service position. | 03-29-2012 |
20120069619 | Modular Power Converters Usable Alone or In A Multiphase Power Converter - A power converter module for use alone or with other modules in a multiphase power converter. The power converter module has an enclosure that surrounds internal components to prevent radiation of electromagnetic energy, which internal components also limit conduction of electromagnetic energy. The internal components include an EMI filter, a ripple filter, a power converter, and a control interface that communicates with a control system of a power conversion system. The control interface includes a memory that stores information related to the power converter modules so as to improve interchangeability of similar power modules with the multiphase power converter. | 03-22-2012 |
20110241343 | Speed Setting System and Method for a Stall-Controlled Wind Turbine - A speed setting system that generates a speed control command for controlling the rotational speed of a stall-controlled wind turbine of a wind-powered machine. The speed setting system generates the speed command as a function of performance variation of the wind turbine due to environmental and/or other factors. The speed setting system utilizes a performance-compensation term that is slowly adjusted to compensate for relatively long-term performance variation. In one example, the performance-compensation term is adjusted only when the current power output of the wind turbine is at least 80% of the rated output power to ensure the wind speed is sufficiently high. | 10-06-2011 |
20110187121 | Wind Turbine/Generator Set and Method of Making Same - A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly. | 08-04-2011 |
20110187120 | Wind Turbine/Generator Set Having A Stator Cooling System Located Between Stator Frame and Active Coils - A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly. | 08-04-2011 |
20110043065 | Method and Apparatus For Permanent Magnet Attachment In An Electromechanical Machine - An apparatus and method for the installation and removal of permanent magnets in a permanent magnet electromechanical machine, for example a wind turbine power unit generator. A magnet holder is mounted on a magnet carrying structure such as a rotor. Permanent magnets may be inserted into and removed from the magnet holder after the electromechanical machine is assembled. In this manner, permanent magnets may be installed on the magnet carrying structure by an interference fit, without using bolts or adhesives, to facilitate both assembly and removal for maintenance and repair. | 02-24-2011 |
20100314936 | Interconnection Switching System and Method for Connecting a Distributed Energy Resource to an Electrical Power System - A distributed energy resource (DER) switching system and method for connecting a DER to an electrical power system (EPS) protector, wherein the DER has a reactance-to-resistance ratio higher than the reactance-to-resistance ratio of the EPS protector. The DER switching system includes an input for receiving power from the DER, and an output for providing power from the DER to the EPS protector. The DER switching system is designed to effectively lower the higher reactance-to-resistance ratio of the DER during an over-current fault so that, during the fault, the effective reactance-to-resistance ratio at the output of the DER switching system is lower than the reactance-to-resistance ratio of the EPS protector. The method includes effectively lowering the reactance-to-resistance ratio of the DER by varying the operating state of a switching device in a controlled manner during the fault. | 12-16-2010 |
20100253078 | Water Turbine System and Method of Operation - A system for providing electrical power from a current turbine is provided. The system includes a floatation device and a mooring. A water turbine structure is provided having an upper and lower portion wherein the lower portion includes a water fillable chamber. A plurality of cables are used to couple the system where a first cable couples the water turbine to the mooring and a second cable couples the floatation device to the first cable. The system is arranged to allow the turbine structure to be deployed and retrieved for service, repair, maintenance and redeployment. | 10-07-2010 |
20090079266 | Electrical Power Distribution System and Method Thereof - An auxiliary electrical power system for providing auxiliary power to an electrical power distribution system containing a plurality of loads and a plurality of primary power sources, wherein each of the primary power sources is electrically connected to one or more of the plurality of loads. In one embodiment, the auxiliary electrical power system includes a generator electrically connected to the plurality of loads. A plurality of power converters are electrically connected between the generator and corresponding respective ones of the plurality of loads. Other embodiments of the auxiliary electrical power system have multiple generators electrically connected to ones of the plurality of loads via corresponding power converters. Methods of implementing an auxiliary electrical power system are also disclosed, as is an arrangement for increasing the reliability of power to a load through a connection with a parallel utility. | 03-26-2009 |
20090026771 | Wind Turbine Having a Direct-Drive Drivetrain - A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly. | 01-29-2009 |