The invention relates to a system, method and device for changing a notional viewing location for a moving image on a device, depending on an orientation of the device. For the moving image management system, it comprises: a sensor; a movement detection module connected to the sensor providing movement data registering a notable signal from the sensor; and a moving image adjustment module determining a new viewing location of the moving image utilizing the movement data and generating a replacement moving image for the moving image representing the moving image as viewed from the new viewing location.

Generating a corrected electronic record of a locate and/or marking operation. The operation comprises locating and/or identifying, using a physical locate mark, presence or absence of an underground facility within a dig area. At least a portion of the dig area may be excavated or disturbed. First information relating to a location of the facility and/or the mark is received. Based at least in part on the first information, the location of the facility and/or the mark is represented to generate an electronic visual representation of the operation. Second information relating to a corrected location of the facility and/or the mark is received. Based at least in part on the second information, the corrected location is represented to generate a corrected electronic visual representation of the operation. Third information relating to the corrected representation of the operation is transmitted and/or stored to generate the corrected electronic record of the operation.

A method is disclosed for assessing an aspect relating to a locate and/or marking operation performed by a locate technician based on an electronic representation of the operation. The operation includes locating and/or identifying, using a physical locate mark, a presence or an absence of an underground facility within a dig area. A portion of the dig area may be excavated or disturbed during excavation activities. The method includes digitally representing, on a display device, the facility and/or the physical locate mark to generate an electronic visual representation of the operation. The method further includes determining a length associated with a portion of the digitally represented facility and/or physical locate mark in the electronic visual representation of the operation. The method further includes, based on the determined length, automatically assessing the aspect relating to the operation.

In one embodiment, a viewer executing on an electronic device having a touch sensitive display shows a three-dimensional (3D) model of a building created using computer aided design (CAD) software. A plurality of selectable interface nodes are provided at respective locations within the 3D model. Each interface node is linked to at least one corresponding two-dimensional (2D) construction drawing that shows a section view, a plan view, an elevation view or a detail view of the building related to the location of the interface node. In response to receiving input from a user indicating selection of a particular interface node, a menu is displayed with one or more selectable menu options. In response to receiving additional input from the user indicating selection of a particular menu option, a corresponding 2D construction drawing for the particular interface node is displayed in context of the 3D model of the building.

Generating a digital-media-enhanced electronic record of a locate and/or marking operation performed by a locate technician. The locate and/or marking operation comprises locating and/or identifying, using at least one physical locate mark, a presence or an absence of at least one underground facility within a dig area, wherein at least a portion of the dig area may be excavated or disturbed during excavation activities. A location of the at least one underground facility and/or the at least one physical locate mark is electronically rendered on a display device so as to generate an electronic visual representation of the locate and/or marking operation. At least one digital media file representation of a corresponding digital media file relating to at least one aspect of the locate and/or marking operation or an environment of the dig area is also electronically rendered on the display device, so as to generate a digital-media-annotated representation of the locate and/or marking operation. Information relating to the digital-media-annotated representation of the locate and/or marking operation is electronically transmitted and/or stored so as to generate the digital-media-enhanced electronic record of the locate and/or marking operation.

Embodiments of the technology involve apparatus and methods for control of displaying of images. In an example, an apparatus may include an image display, a sensor to detect posture of the image display and a processor to control sequentially displaying images of a group of images on the image display based on changes in the detected posture. The processor may control a display of a posture indicator on the image display such that the indicator may represent a relation between a change in the detected posture and an image of the group of images. Optionally, the indicator may be represented by a tilt meter. Moreover, in some embodiments, the sensor may be implemented with a gyroscopic sensor.

A balun including a first conductor winding, a first inductor, a second inductor, a third inductor, and a fourth inductor. The first conductor winding has a figure eight shape including a first loop and a second loop. The first inductor and the second inductor substantially surround the first loop. The third inductor and the fourth inductor substantially surround the second loop.

In an example embodiment, an electromagnetic interface can comprise: a first component comprising a first waveguide channel, a first interface surface, and a first force transfer feature; a second component comprising a second waveguide channel, a second interface surface, and a second force transfer feature; and a fastener that can be configured to force the first force transfer feature in sliding engagement with the second force transfer feature. The first and second force transfer features can be configured to interoperate to create an indirect force holding the first interface surface in contact with the second interface surface and holding the first waveguide channel in alignment with the second waveguide channel.

Mechanically short multi-carriage impedance tuners use meandering slabline structures. The meandering structure reduces the overall tuner length by a factor of 2.5 at 0.4 GHz. The critical issue of slabline bends is addressed with several low loss, low reflection alternatives. A preferred configuration comprises a vertical-horizontal slabline transition. Cable connections are discarded because of reflections and insertion loss. Measured results show acceptable performance. The tuner is mostly interesting for relatively lower microwave frequencies, such as 1 GHz.

Implementations for exciting two or more modes via modal decomposition of a pulse by a wave launcher are generally disclosed.

A paint dispensing nozzle arrangement for dispensing paint into a paint applicator, the paint applicator having a base plate, an interface material to allow the paint to adhere to the base plate, and a removable paint mold, the nozzle arrangement comprising a dispensing nozzle for dispensing paint into the paint mold, and a displacement member, the displacement member arranged relative to the dispensing nozzle such that the nozzle can dispense paint into the paint mold without coming into contact with the interface material.

In a method for transferring energy between at least two energy storage cells in a controllable energy store that serves to control and to supply electrical energy to an n-phase electric machine, which energy store has n power supply arms which each have at least two series-connected energy storage modules which each include at least one electrical energy storage cell with an associated controllable coupling unit, and are connected to one respective phase of the electric machine, in a charging phase, all coupling units of those energy storage modules which are to be used as an energy source are controlled in such a way that the respectively associated energy storage cells are connected into the respective power supply arm.

An energy management system has an integration control portion that performs control to charge a storage battery with a power of such an amount that a power consumption including a power supplied by a supply portion is equal to or smaller than a target value indicated by power consumption target information recorded in a recording portion when a power consumption detected by a detection portion is smaller than the target value, and to supply a building with a power with which the storage battery is charged such that the power consumption including the power supplied by the supply portion coincides in amount with a power equal to or smaller than the target value indicated by the power consumption target information recorded in the recording portion when the power consumption detected by the detection portion is larger than the target value.

State based full and empty control for rechargeable batteries that will assure a uniform battery empty condition, even in the presence of a load on the battery. A fuel gauge provides a prediction of the open circuit voltage of the battery, and when the predicted open circuit voltage of the battery reaches the predetermined open circuit voltage of an empty battery, the load is terminated, after which the battery will relax back to the predetermined open circuit voltage of an empty battery. A similar technique is disclosed for battery charging, allowing faster battery charging without overcharging. Preferably an RC battery model is used as the fuel gauge to provide the prediction, but as an alternative, a coulomb counter may be used to provide the prediction, with error correction between successive charge discharge cycles.

The present inventions, in one aspect, are directed to techniques and/or circuitry to adapt the charging of a battery using data which is representative of an overpotential or relaxation time (full or partial) of the battery. In another aspect the present inventions are directed to techniques and/or circuitry to calculate data which is representative of an overpotential or relaxation time (full or partial) of the battery. In yet another aspect the present inventions are directed to techniques and/or circuitry to calculate data which is representative of a state of charge of the battery using an overpotential or relaxation time (full or partial) of the battery.

A charging device with a battery management system which remains a rechargeable battery in full capacity during standby after being fully charged is disclosed. The charging device includes a charging module, electrically connected to a power source, for charging the rechargeable battery; a voltage detecting module, for detecting a voltage of the rechargeable battery; and a determination module, for instructing the charging module to charge the rechargeable battery with a supplementary current, when the voltage of the rechargeable battery detected by the voltage detecting module reduces to a first predetermined voltage, until the voltage of the rechargeable battery reaches a second predetermined voltage. A reduction of the voltage of the rechargeable battery is due to self-discharge of the rechargeable battery during standby after being fully charged.

According to an embodiment of the present invention, a recharging device includes a recharging port that receives a flameless candle and recharges a battery in the candle. The recharging device includes a first stacking structure that has a top portion and a bottom portion. There is a top stacking contact on the top portion. An electrical power bus is connected with the top stacking contact. The electrical power bus is also configured to provide electrical power to the flameless candle through the recharging port. The top portion of the first stacking structure is configured to mate with a bottom portion of a first stacking structure of another recharging device.

A battery system is disclosed. The battery system includes a plurality of battery cells, and a battery cell balancing unit, configured to adjust voltages across each of the battery cells to reduce variation among the voltages across the battery cells. The battery cell balancing unit includes a controller configured to receive a DC reference current and to generate an AC current based on the DC reference current, a transformer, a rectifier circuit including a rectifier connected to the output coil, and a switching unit including a plurality of switches, each configured to selectively connect the rectifier to one of the battery cells.

A charger includes a loading chamber into which a battery pack is insertably/removably loaded. An insertion opening into which the battery pack is inserted is formed on an upper surface of the main body. The loading chamber is forwardly inclined to a front surface of the main body, and a bottom surface of the insertion opening is inclined with respect to a horizontal direction so that one end of the front surface side is located at a lower end and the other end of the back surface side is located at an upper end. A connector for supplying power is disposed at the upper end side of the bottom surface. Even when the dust, rubbish or fluid entered from the insertion opening drops to the bottom surface, it flows down to the lower end side, so that less dirt adheres to the connector.

A belt battery charger includes a belt having a first end, a second end and an elongated central portion extending between the first and second ends. A plurality of electrically connected rechargeable batteries are carried by the central portion of the belt. A belt buckle located at the first end of the belt includes a frame that is secured to the central portion of the belt. The buckle further includes a prong in the form of an electrical connector electrically connected to the batteries and pivotally secured to the frame. The second end of the belt includes a number of spaced apart eyelets passing therethrough. The prong is shaped so as to be able to enter one of the eyelets to secure the second end of the belt to the buckle in the conventional manner. A second electrical connector is located adjacent the second end of the belt and is also connected to the batteries. One of said connectors is adapted to be connected to a cell phone for charging the same.

A battery fuel gauge apparatus comprises a current amplifier formed by a first transistor and a second transistor. Both transistors operate in the same operation conditions except that the second transistor has a smaller channel width in comparison with that of the first transistor. The first transistor is connected in series with a battery pack. The second transistor is connected in series with a sensing device. The sensing device comprises a first resistor and a second resistor connected in series. The first resistor has a positive temperature coefficient and the second resistor has a negative temperature coefficient.

An energy storage system and a method of controlling the same is provided. The energy storage system may directly provide generated DC power or DC power stored in a battery to a DC load without performing a DC/AC conversion or an AC/DC conversion. Furthermore, in the case where a grid operates abnormally (e.g. power interruption) and the energy storage system functions as an uninterruptible power supply (UPS), power stored in a battery may be selectively provided to loads according to power remaining in a battery, and thus stored power may be used stably.

According to some embodiments, battery charge management using a scheduling application is disclosed. A first parameter may be received from a scheduling application running on a mobile computing device having a battery pack. Based on at least the first parameter and battery pack data, a required charge percentage for the battery pack may be determined and the remaining capacity of the battery pack may be determined. If the remaining capacity of the battery pack is less than the required charge percentage, a charge termination voltage may be determined and the battery pack may be charged to the charge termination voltage.

An apparatus for minimizing self-discharge of a smart battery pack is provided. During initial storage of the smart battery pack (100), prior to be being charged, a self-discharge protection circuit (110) disables smart battery circuitry (130). A minimal current drain is maintained while the smart battery circuitry (130) is disabled. Upon coupling of the smart battery pack (100) to a charger, the protections circuit (110) enables the smart battery circuitry (130). Battery packs having to be shipped with partially drained cells as part of shipping precaution requirements are no longer faced with the additional drainage problem previously caused by the smart battery circuitry (130) during storage.

A discharge device actively discharges a main capacitor in an electric-power system of an electric-drive vehicle and comprises a discharge branch of a circuit connected in parallel to the capacitor and including a discharge transistor biased to “conduction” mode when the capacitor must be discharged. A control device is connected to a “gate/base” terminal of and controls the transistor, biasing the transistor to the mode when the capacitor is required to fee discharged. A control transistor maintains the discharge transistor in a “non-conductive” state when the control transistor is in the mode. The control transistor is in the state for the discharge transistor to be in the mode. A safety capacitor is interposed between the terminal and a power supply and charges when the discharge transistor is in the mode, causing a progressive decrease of current at the terminal, until the discharge transistor is biased to the state.

A battery voltage detector includes, but is not limited to: a voltage detection circuit; and a voltage processor. The voltage detection circuit includes, but is not limited to: a capacitor configured to be charged by a battery cell; a pair of output terminals; an output switch; and a voltage processor. While the capacitor is charged, the output switch is configured to be off-state and insulate the capacitor from the pair of the output terminals. After the capacitor is charged, the output switch is configured to be on-state and connect the capacitor to the pair of the output terminals. The voltage processor is configured to obtain, as a cell voltage, a voltage between the output terminals of the voltage detection circuit while the output switch is on-state. A high-potential output terminal of the pair of the output terminals is connected to a power line via a pull-up resistor.

An charging device includes: capacitors connected in series; a charging unit that charges the capacitors; bypass units, each respectively connects in parallel to each capacitors, wherein each bypass unit causes, when a charged voltage of any capacitor has reached a set voltage, a charging current to bypass the capacitor whose charged voltage has reached the set voltage; and a control unit that controls the charging unit to charge the capacitors in such a manner that, when a charging voltage of the any capacitor has reached the set voltage, the control unit causes the charging unit to reduce the charging current, and if a predetermined period has elapsed since the charging voltage has reached the set voltage, and if a charging voltage of any of the other capacitors has not reached the set voltage after the predetermined period, the control unit causes the charging unit to increase the charging current.

An electricity generation device includes a permanent-magnet electric generator with three or more phase windings each having an output terminal and connected to a neutral point, and bidirectional semiconductor switching circuits capable of interrupting connections between the respective phase windings and the neutral point. Each switching circuit allows current to flow in both directions. A gate signal generation circuit outputs to one of the switching circuits during a period including the time at which the AC voltage excited in the corresponding phase winding turns from positive to negative and during a period including the time at which the AC voltage excited in the corresponding phase winding turns from negative to positive. A startup gate signal output circuit outputs a startup gate signal to all of the bidirectional semiconductor switching circuits when the permanent-magnet electric generator is to be started.

Starting and stopping an engine is automatically controlled based on a load without using a relay. An inverter engine-driven power generator has an alternator, a rectifying circuit, a DC/DC converter, and an inverter circuit. A load detection circuit is connected to an output of the inverter circuit in parallel. A load detection line of the load detection circuit is connected to an output line of the inverter circuit in parallel via resistors. A power supply formed of a battery is connected to the load detection line. A decision circuit outputs a load detection signal when a current having a preset value or more flows through the load detection line. A drive/stop CPU starts the engine in response to the load detection. The resistors are set at a resistance value which does not influence a load to which a generator output is supplied.

The excitation overcurrent detection unit for the doubly-fed electric machine is provided with a function to determine an excitation current magnitude relationship among three phases. The firing pulse is held to on-state or off-state to cause the largest-current phase and the second-largest-current phase to charge the DC capacitor by the operation of diodes. The conduction ratio of the third-largest-current phase or minimum current phase is controlled according to the detected current value to protect against a possible short-circuit across the DC capacitor. When the voltage of the DC capacitor exceeds a preset value, the voltage is suppressed by operating active or passive power devices.

An electrical generator includes a stator having fractional-slot concentrated windings and a rotor having field windings. A drive is provided having a circuit to control current flow to the field windings and a controller to input an initial DC field current demand to the circuit to cause the circuit to output an initial DC field current representative of a DC field current demand that would cause an electrical generator having sinusoidal stator windings to output a desired AC power. The controller receives feedback on the magnetic field generated by the initial DC field current, isolates an ideal fundamental component of the magnetic field based on the feedback and to generate a modified DC field current demand, and inputs the modified DC field current demand to the circuit, thereby causing the circuit to output an instantaneous non-sinusoidal current to the field windings to generate a sinusoidal rotating air gap magnetic field.

A wind power generator generates power through a rotation of a rotor and is interconnected, and operated with its power generation output previously limited in order to be able to further supply the power to a power system in response to a decrease in system frequency. Thus, a concentrated control system derives a required restricted amount corresponding to a power generation output required to respond to the decrease in system frequency, derives a value by subtracting an amount corresponding to a latent power generation output with which the power generation output can be increased, from the required restricted amount, and sets a restricted amount of the power generation output in each wind power generator to perform the operation with the power generation output previously limited to respond to the decrease in system frequency, based on the above value.

A generator system includes a generator having a stationary portion and a rotating portion. The generator includes a permanent magnet based exciter with permanent magnets disposed on the stationary portion. A first channel includes a first main field winding and a first main field power converter disposed on a rotating portion. The first main field power converter selectively delivers voltage from the exciter winding to the first main field winding. A second channel includes a second main field winding and a second main field power converter disposed on the rotating portion. The second main field power converter selectively delivers voltage from the exciter winding to the second main field winding. A generator control unit is connected to the first channel and the second channel. The generator control unit monitors an output voltage at each of the first channel and the second channel and generates the first and second control signals based on the output voltage.

An inverter generator used in combination with a motor and an ECU generating a pulse at each predetermined rotation angle of the motor is comprised of: an electric generator driven by the motor configured to generate alternating current electric power; estimating means for estimating an electrical angle of alternating voltage of the alternating current electric power from the pulse, the estimating means being electrically connected with the ECU; a converter configured to convert the alternating current electric power into direct current electric power, the converter electrically connected with the electric generator and the estimating means; and an inverter configured to convert the direct current electric power into alternating current output electric power, the inverter electrically connected with the converter.

The control system of this floating wind turbine generator is a control system of a floating wind turbine generator in which the control system controls a pitch angle control section by a pitch angle instruction value calculated on the basis of signals detected by a second sensor detecting a relative angle between a nacelle and a tower and a third sensor detecting a yaw angle from a reference position of the tower so that a signal detected by a first sensor detecting wind direction deviation relative to a vertical direction of a rotation plane of wind turbine blades indicates an angle within a predetermined range from the vertical direction of the rotation plane of the wind turbine blades, and controls a yaw driving device by a yaw driving instruction value calculated on the basis of the signals detected by the second sensor and the third sensor.

A DC chopper comprising a control unit and a power circuit and a DC chopping method for a DFIG (doubly fed induction generator) system are provided. The input terminal of the control unit is coupled to a DC capacitor of a converter to detect a DC voltage. The power circuit includes input terminals, an overvoltage protection module, a rectifier module and output terminals. The overvoltage protection module comprises at least one discharge unit formed from a discharge resistor and a switch element, and the rectifier module is coupled in parallel to the overvoltage protection module. When a grid voltage drops, the control unit outputs a corresponding control signal to drive the switch element to be ON or OFF, and the output terminal of the power circuit absorbs a portion of rotor inrush current, so as to impose over-current protection.

An electric power generation system (EPGS) employs both a wild-source generator and a variable and/or constant frequency generator. The wild-source generator is coupled to receive mechanical power from a low-pressure spool on an aircraft engine and to generate in response a wild-source output for consumption by voltage and frequency-tolerant loads. The variable and/or constant frequency generator is coupled to receive mechanical power from a high-pressure spool on the aircraft engine and to generate in response a variable and/or constant frequency output for consumption by voltage and frequency-intolerant loads.

An integrated power system suitable for simultaneously powering marine propulsion and service loads. The system includes: (a) at least one generator configured with at least first and second armature windings configured to output respective first and second alternating current power signals of different voltages, the at least two armature windings positioned within the same stator slots so that they magnetically couple; (b) at least first and second rectifier circuits coupled to said generator to convert said first and second alternating current power signals into first and second direct current power signals; and (c) a first load to which said first direct current power signal is coupled and a second load to which said second direct current power signal is coupled.

An electrical machine includes a stator having a main armature winding, an exciter field winding, and a transformer primary winding. A rotor is operatively connected to rotate relative to the stator, wherein the rotor includes an exciter armature winding operatively connected to the exciter armature winding for field excitation therebetween, a main field winding operatively connected to the main armature winding for field excitation therebetween, and a transformer secondary winding operatively connected to the transformer primary winding to form a rotating transformer. A generator control unit is operatively connected to the main armature winding, exciter field winding, and transformer primary winding to control the main armature and exciter field windings based on excitation in the primary winding received from the transformer secondary winding.

A method for converting heat to electric energy is described which involves thermally cycling an electrically polarizable material sandwiched between electrodes. The material is heated by extracting thermal energy from a gas to condense the gas into a liquid and transferring the thermal energy to the electrically polarizable material. An apparatus is also described which includes an electrically polarizable material sandwiched between electrodes and a heat exchanger for heating the material in thermal communication with a heat source, wherein the heat source is a condenser. An apparatus is also described which comprises a chamber, one or more conduits inside the chamber for conveying a cooling fluid and an electrically polarizable material sandwiched between electrodes on an outer surface of the conduit. A gas introduced into the chamber condenses on the conduits and thermal energy is thereby transferred from the gas to the electrically polarizable material.

A magnetic controlled power generator provides a magnetic controlled loading device, power generator and flywheel device to form two independent modules which are easily assembled and disassembled for easy manufacture and maintenance. Besides, the magnetic controlled power generator has simple installation and lightweight components to generate a radial displacement for magnetic flux control, achieving continuous adjustment of the load resistance, thereby having the effect of reducing the cost and weight.

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.

A dip in the output voltage of a motor-vehicle alternator, owing to a connecting of a load or a change in speed, is compensated with the aid of an alternator regulator which provides a control signal that has a duty factor and increases the excitation current of the motor-vehicle alternator. After the occurrence of the voltage dip, in a first step, the duty factor of the control signal is increased by a differential amount, and in a subsequent second step, the rate of correction is limited. After the occurrence of the voltage dip, parameters describing the instantaneous working point of the motor-vehicle alternator are determined, and in the first step, the differential amount is set as a function of the working point.

Systems and methods for monitoring excitation of a generator based on a faulty status of a generator breaker are provided. According to one embodiment, a system may include a controller and a processor communicatively coupled to the controller. The processor may be configured to receive, from a contact associated with a generator breaker, a reported status of the generator breaker, receive operational data associated with one or more parameters of a generator associated with the generator breaker, and correlate the reported status of the generator breaker and the operational data. Based on the correlation, the processor may establish an actual status of the generator breaker, and, based on the actual status, selectively modify a mode of excitation of the generator.

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. Either a fixed reference threshold is used or a reference threshold voltage is calculated based upon the duration in over voltage condition, and the switch is modulated between the open and closed conditions according to error between the actual output voltage and the reference threshold voltage to limit the output voltage to the desired reference threshold voltage.

A method of controlling a generator (110) of an electric drive (104) associated with an engine (102) is provided. The method may determine an operational state of the electric drive (104) based on a speed of the engine (102), and selectively engage one of a map-lookup control scheme (150) and a fixed-theta off control scheme (152) for operating the generator (110) based on the operational state of the electric drive (104).

A power supply system for a motor vehicle includes a generator that includes a rotor having a field coil and a stator having an armature coil; a rectifier that rectifies AC power generated in the armature coil; an excitation control circuit that takes control of a voltage applied to the field coil; a capacitor that is connected to the DC side of the rectifier, and receives and transfers the rectified power; a battery connected to an electric load of the motor vehicle; a DC-DC converter that is connected between the capacitor and the battery and capable of converting unidirectionally or bidirectionally an input DC voltage into any DC voltage; and a selection switch which connects the capacitor or the battery to the excitation control circuit as a power supply source.

A method for converting heat to electric energy is described which involves thermally cycling an electrically polarizable material sandwiched between electrodes. The material is heated using thermal energy obtained from: a combustion reaction; solar energy; a nuclear reaction; ocean water; geothermal energy; or thermal energy recovered from an industrial process. An apparatus is also described which includes an electrically polarizable material sandwiched between electrodes and a heat exchanger for heating the material. The heat source used to heat the material can be: a combustion apparatus; a solar thermal collector; or a component of a furnace exhaust device. Alternatively, the heat exchanger can be a device for extracting thermal energy from the earth, the sun, ocean water, an industrial process, a combustion reaction or a nuclear reaction. A vehicle is also described which comprises an apparatus for converting heat to electrical energy connected to an electric motor.

A thermionic generator for converting thermal energy to electric energy includes: an emitter electrode for emitting thermal electrons from a thermal electron emitting surface when heat is applied to the emitter electrode; a collector electrode facing the emitter electrode spaced apart from the emitter electrode by a predetermined distance, and receiving the thermal electrons from the emitter electrode via a facing surface of the collector electrode; and a substrate having one surface. The emitter electrode and the collector electrode are disposed on the one surface of the substrate, and are electrically insulated from each other. The thermal electron emitting surface and the facing surface are perpendicular to the one surface.

A method of operating a converter of a wind turbine for providing electric energy to a utility grid includes determining a grid voltage. If the grid voltage is between a nominal voltage and a first voltage threshold, i.e. higher than the nominal voltage, a normal procedure for lowering the grid voltage is performed. If the grid voltage is above the first voltage threshold, another procedure for keeping the wind turbine connected is performed, wherein the other procedure is different from the normal procedure. Further a corresponding arrangement is described.