The present disclosure provides devices, methods and systems for enabling low cost, high quality education in under- resourced regions such as post disaster areas. The devices provided herein may be charged and used without the need of sustainable power resources or access to internet at all times.

An engine generator coupled to an external battery. The engine generator includes: an engine; a motor generator configured to apply a starting force to the engine at a start of the engine, and to perform power generation by a driving force of the engine during driving of the engine;

a first step-down section and an engine accessory, the first step-down section being configured to step down a voltage of the external battery to obtain a first stepped-down voltage, and supply the first stepped-down voltage to the engine accessory; and a power converter that converts power of the external battery and supplies the converted power to the motor generator.

A vehicle propulsion system comprises a combustion engine with a flywheel secured to a crank shaft of the engine. A starter motor and a generator are combined in one electric machine having a stator rigidly connected to a vehicle frame fixed part and provided with windings connected to an arrangement storing electric energy for being fed with electric energy from the arrangement in motor operation of the electric machine and feeding electric energy to the arrangement in generator operation of the electric machine and a rotor connected to the flywheel so as to make the rotor and flywheel rotating in dependence of each other. At least one of the stator and rotor has a member projecting into a recess portion of the other so as to form air gaps for magnetic flux between the rotor and the stator on both sides of the projecting member.

A method and an apparatus for controlling noise of a wind turbine. The method includes: determining a noise-influencing sector of the wind turbine based on a position of the wind turbine and a position of a noise-influencing site; acquiring a current wind direction; determining whether the wind turbine under the current wind direction operates in the noise-influencing sector; and limiting output power of the wind turbine, and increasing, after the wind turbine goes out from the noise-influencing sector and the output power reaches a rated power, the output power, in a case that the determination is positive.

An electronic timepiece, including: a motor having a rotor and at least two coils, the rotor being configured to rotate to a plurality of prescribed positions; and a driving processor for driving the motor, the driving processor being configured to: generate a detection pulse for detecting whether or not the rotor has rotated; cause the generated detection pulse to be applied to at least one of the at least two coils; receive a signal indicating a detected value of current flowing in the at least one of the at least two coils that is generated in response to the detection pulse outputted to the at least one of the at least two coils; and determine whether or not the rotor has rotated to one of the plurality of prescribed positions on the basis of the detected value of current.

A downhole system includes a drill string having a drilling fluid flow channel and at least one turbine alternator deployed in the flow channel. The turbine alternator is configured to convert flowing drilling fluid to electrical power. A voltage bus is configured to receive electrical power from the turbine alternator and at least one electrical motor is configured to receive electrical power from the voltage bus. An electronic controller is configured to provide active control of the turbine alternator via processing a desired speed of the electrical motor to generate a desired torque current and feeding the desired torque current forward to the turbine alternator. The turbine alternator is responsive to the desired torque current such that it modifies the electrical power provided to the voltage bus in response to the desired torque.

A modular wind turbine system and a method of use thereof are provided. The system comprises: a mounting frame; a fixed toroidal support structure attached to the mounting frame, the toroidal support structure having a concave portion and a convex portion; a wind turbine located proximal to the concave portion of the toroidal support structure, wherein the wind turbine travels about at least a portion of the concave portion of the toroidal support structure; and a first baffle, wherein the first baffle extends about the portion of the concave portion of the toroidal support structure about which the first turbine travels, wherein the baffle surrounds a portion of the wind turbine opposite the fixed toroidal support structure, and wherein the baffle includes at least one component selectively variably adjustable so as to vary the force, direction, or disruption of flow of fluid thereby, relative to the wind turbine.

A system and method are provided for controlling a wind turbine of a wind farm. Accordingly, a controller implements a first model to determine a modeled performance parameter for the first wind turbine. The modeled performance parameter is based, at least in part, on an operation of a designated grouping of wind turbines of the plurality of wind turbines, which is exclusive of the first wind turbine. The controller then determines a performance parameter differential for the first wind turbine at multiple sampling intervals. The performance parameter differential is indicative of a difference between the modeled performance parameter and a monitored performance parameter for the first wind turbine. A second model is implemented to determine a predicted performance parameter of the first wind turbine at each of a plurality of setpoint combinations based, at least in part, on the performance parameter differential the first wind turbine. A setpoint combination is then selected based on the predicted performance parameter and an operating state of the first wind turbine is changed based on the setpoint combination.

A converting device arranged to transfer thermodynamic energy of a compressed working fluid into electrical energy. The converting unit is comprised of at least one cylinder which encloses a piston. In an embodiment, said at least one piston is provided with a magnetic portion. A ferromagnetic coil surrounds the piston and is integrated with the cylinder. As the piston moves through the coil, electrical energy is generated.

A converting device arranged to transfer thermodynamic energy of a compressed working fluid into electrical energy. The converting unit is comprised of at least one cylinder which encloses a piston. In an embodiment, said at least one piston is provided with a magnetic portion. A ferromagnetic coil surrounds the piston and is integrated with the cylinder. As the piston moves through the coil, electrical energy is generated.