Abstract: An AC/DC conversion circuit of a power conversion apparatus receives an AC signal and has a switching element. A voltage sensing circuit generates a voltage reference signal according to an AC voltage signal. A harmonic generation circuit generates a harmonic injection signal according to the voltage reference signal. A subtraction circuit of a maximum power tracking circuit outputs a first DC signal and a second DC signal according to the voltage reference signal. An arithmetic circuit outputs a reference signal. A current sensing circuit outputs a feedforward signal according to one phase of an AC current signal. A current control circuit outputs an error signal according to the reference signal and the feedforward signal. A pulse width modulation circuit outputs a control signal to control the switching element according to the error signal and the harmonic injection signal, so that an aerogenerator operates at the maximum power approximation line.

Abstract: An energy harvesting apparatus is described that utilizes hydraulic actuation and creates a continuous, revolving motion of a chain of energy-producing elements within an energy-producing channel (the channel being in the form of a tube, for example). In particular, the arrangement of the present invention is based upon a specially-designed dual-loop channel topology that allows for efficient conversion of a unidirectional flow of a fluid entering the energy-producing channel into a smooth, continuous revolving motion of a chain of energy-producing elements within the channel.

Abstract: A wind powered apparatus (or wind turbine) comprising a stator blade assembly and a rotor blade assembly wherein said stator blades assembly and said rotor blade assembly have counter rotating blades. Both sets of blades assemblies are connected to a generator and are operable to rotate the stator and rotor thereof in opposite directions relative to one another due to the blade arrangement between assemblies. The blades assemblies comprise a hub connected to an outer ring, wherein said outer ring comprises inward blades. The win turbine, more particularly the blade arrangement co-operates to improve performance of the apparatus by affecting its orientation and the rotational speed of the blades.

Abstract: There is provided a control device for an internal combustion engine. An electricity generator is configured to be driven by the internal combustion engine. A battery is configured to store electricity generated by the electricity generator. A discharge amount detection section is configured to detect a discharge amount of the battery. An automatic stop control section is configured to automatically stop the internal combustion engine when the discharge amount is a first setting value or less. A continuous discharge amount detection section is configured to detect a continuous discharge amount of the battery based on the discharge amount. An automatic stop prohibition section is configured to prohibit an automatic stop when the continuous discharge amount is a second setting value or more, which is lower than the first setting value.

Abstract: A fluid-cooled wind turbine has at least one electric machine, in turn having a stator with a stator supporting structure and a plurality of active stator sectors supported by the stator supporting structure, and a rotor which rotates about an axis of rotation and has a rotor supporting structure and a plurality of active rotor sectors supported by the rotor supporting structure; and a cooling system having a cooling circuit extending partly along a plurality of through channels adjacent to at least the active rotor sectors or the active stator sectors.

Abstract: The invention relates to a wind turbine with internal transport devices which comprises: a power train including a generator (41) located in front of the rotor (15) and actuated directly by said rotor (15), a tower (11) and a supporting structure (13) mounted on the tower (11); the rotor (15), which is supported by a main non-rotating shaft (29) connected to the supporting structure (13) by means of at least one bearing, comprising a hub (17) and at least one blade; the generator rotor (45) being rigidly connected to the rotor hub (17) and the generator stator (43) being rigidly connected to the main shaft (29), the main shaft (29) being a hollow shaft which includes one or more transport devices, such as a device (61) for transporting hanging loads or a carriage (71) for making it easier to replace parts of the generator and/or to transport persons.

Abstract: Provided is a doubly-fed induction generator system and a self-test method for the active crowbar circuit of the doubly-fed induction generator system. The invention is featured by using the controller of the doubly-fed induction generator system to carry out a self-test procedure to detect the loop current of the active crowbar circuit for determining if the active crowbar circuit can be turned on and off normally. Also, the rotor-side converter and the active crowbar circuit of the doubly-fed induction generator system are forbidden to turn on simultaneously during the execution of the self-test procedure.

Abstract: A method is provided for operating a controller controlling an energy production plant including plural wind turbines each having an electrical output terminal connected to a common node. The method involves determining that a failure relating to the energy production plant has been overcome; receiving a first signal indicative of an actual value of an electrical quantity at the common node; receiving a second signal relating to a desired value of the electrical quantity at the common node; generating plural reference signals based on an intermediate value between the actual value and the desired value; and supplying the reference signals to the wind turbines, the reference signals controlling the wind turbines with respect to their electrical output at the output terminal such that the intermediate value of the electrical quantity at the common node is achieved.

Abstract: Transverse and longitudinal wave energy is transformed into useful mechanical energy. The basic unit is composed of a linkage body with a socket located at each end. A main bevel gear inserted into each socket engages with a bevel gear attached to a transverse power shaft. A one way clutch permits the bevel gear to move in one direction. A number of these units can be connected end on end to magnify the mechanical energy transformed from wave energy. The terminus of the transverse power shaft is connected to the rotor of an electrical generator. As the linkage bodies interact with the force of the waves, the transverse power shaft is rotated which then causes the rotor of the electric generator to spin creating electricity.

Abstract: An energy harvesting apparatus utilizes a modular structure to preserve the proper alignment between a chain of energy-producing elements and an energy-producing channel (within which the chain is located and free to slide along, creating electrical energy from mechanical movement). The channel includes a plurality of rigid modules that are separated by flexible segments of tubing. The rigid channel modules house the energy-producing electrodes and/or coils. The chain includes a plurality of rigid modules that are attached along a flexible string in a spaced-apart configuration. The rigid chain modules house the energy-producing magnets and/or conductive droplets. The combination of the flexible channel segments and chain string allow for freedom of motion of the apparatus (required for human locomotion, for example), while providing the desired “fixed” alignment between the rigid energy-producing modules.

Abstract: A DC power generating system includes a permanent magnet generator (PMG), an active rectifier in electrical communication with the PMG, and a controller in electrical communication with the active rectifier, wherein the controller is configured to regulate d-q components of a stator current of the PMG in a synchronous reference frame.

Abstract: A system for converting wind power to electrical energy has a peripheral frame, sails interconnected to the peripheral frame, radial struts extending from the hub to the peripheral frame, wheels mounted on the peripheral frame, electric generators interconnected with respective wheels, and a hub about which the peripheral frame is rotatable. The hub is in electrical communication with the electric generators. Sails may be interconnected with the peripheral frame on respective masts, each mast having a base and the mast being pivotable about the base. The electric generators may be mounted on a variety of locations, such as the peripheral frame. Each electric generator may be interconnected with a respective wheel via a belt, a chain or other mechanism. The system may include arrangements to generate electricity from sunlight.

Abstract: A double fed induction generator (DFIG) converter method are presented in which rotor side current spikes are attenuated using series-connected damping resistance in response to grid fault occurrences or grid fault clearances.

Abstract: Embodiments of the subject invention pertain to a method and apparatus for vibrational energy harvesting via electromagnetic induction using a magnet array. Specific embodiments of the subject invention incorporate at least one conductive coil and at least one magnet array. Magnets used in such magnet arrays can be permanent magnets of various shapes, such as arc-shaped, square, rectangular, wedge, or trapezoidal. These magnet arrays can then be, for example, circular, hexagonal, rectangular, or square in external shape and create various types of internal magnetic fields, such as dipole, quadrupole, hexapole, or octapole magnetic fields. Through use of a magnet array, embodiments of the invention can increase the strength of magnetic fields by approximately 10 times compared to typical vibrational energy harvesters. The 10 time increase in the strength of the magnetic fields can result in up to a 100-fold increase in power.

Abstract: Systems and methods for reducing current imbalance between parallel bridge circuits used in a power converter of a doubly fed induction generator (DFIG) system are provided. A control system can monitor the bridge current of each of the bridge circuits coupled in parallel and generate a feedback signal indicative of the difference in bridge current between the parallel bridge circuits. Command signals for controlling the bridge circuits can then be developed based on the feedback signal to reduce current imbalance between the bridge circuits. For instance, the pulse width modulation of switching devices (e.g. IGBTs) used in the bridge circuits can be modified to reduce current imbalance between the parallel bridge circuits.

Abstract: A cogeneration apparatus includes an electrical generator, an engine for driving the generator, and a heat exchanger for using waste heat of the engine as a heat source, which are housed in a housing. The apparatus is provided with an internal fuel line for supplying fuel to the engine from outside, and power wiring for supplying electrical power generated by the electrical generator to the outside. The housing has a substantially V-shaped lead-out part capable of leading the fuel line and the wiring to outside of the housing.

Abstract: A system, in one embodiment, may include a static starter subsystem having detection logic for indicating a conductive state of a solid state semiconductor device. The detection logic includes a first logic gate having a first input that receives a first input signal indicating a state of the static starter subsystem, a second input that receives a second input signal indicating a state of a gate firing command being applied to the solid state semiconductor device, and a third input that receives a third input signal indicating whether the solid state semiconductor device is conducting. The first logic gate may be configured to evaluate the first, second, and third input signals and provide a first output signal indicating conductivity of the solid state semiconductor device in response to the gate firing command.

Abstract: A DC motor assembly (10) with soft starting capability is provided. The assembly (10) comprises a DC motor (12) including an armature (14) and a field winding (16) adapted to be excited separately from the armature; and circuitry configured to controllably increase current flow through the field winding of the DC motor as a function of time during starting of the DC motor.

Abstract: A generator includes a permanent magnet generator, an exciter and a main generator mounted for rotation on a shaft. The main generator is configured to produce a voltage output. A generator control unit includes a circuit configured to provide current from the permanent magnet generator to the exciter. A switch is provided in the circuit and is configured to change between open and closed conditions. The switch is configured to flow current in the circuit in the closed condition and interrupt current flow in the open condition. An overvoltage limit controller is programmed to determine an amount of overvoltage of the output voltage exceeding a desired voltage.

Abstract: Some embodiments relate to a method of controlling speed of a variable speed generator. The method includes detecting a load of the variable speed generator and determining a target speed for the variable speed generator based on the load supplied by the variable speed generator. The method further includes using a controller to adjust the speed of the variable speed generator based on the target speed. The method may further include correcting the target speed by calculating a correction factor that corrects the target speed based on a voltage produced by the variable speed generator.