Abstract: An energy storage system includes a power source configured to generate power. The energy storage system also includes an induction machine coupled to an inertial flywheel, the induction machine configured to receive electrical energy from the power source, store the energy in the flywheel, and deliver a first portion of the energy to a first pulsed load. The energy storage system further includes a damping network configured to receive and absorb a second portion of the energy at a controlled rate to regulate torsional oscillations in a rotary motion of the flywheel caused by load swings or pulsations of the first pulsed load.

Abstract: Described are concepts, systems and methods for operating microgrid systems both during normal operation conditions and during sudden, unexpected occurrences of a fault which results in a source becoming disconnected from a primary supply. This is achieved through control systems and method based upon multi-layered modeling of system controllable components and their interactions. This approach results in controllable components capable of operation in a “plug-and-play” manner.

Abstract: A method to provide control for an alternating current generator. The method includes controlling the alternating current generator by modulating a three-phase wound rotor to counter-rotate the magnetic field relative to a shaft rotation, or alternatively to become synchronous to the shaft rotation. The three-phase wound rotor controls a frequency and a voltage of the alternating current generator.

Abstract: In one implementation, a voltage boost assembly including a boost converter having a capacitive element arranged at an output, and an inductive element connectable to an electrical supply. The voltage boost assembly also includes a sensor assembly provided to generate a quick-start enable signal in response to detecting that an electrical condition relative to an electrical output of the boost converter has breached a first threshold. The voltage boost assembly further includes a quick-start module responsive to the quick-start enable signal, and configured to drive the boost converter at a relatively high duty-cycle and so that the boost converter delivers an output current that satisfies a second threshold in order to charge the capacitive element arranged at the output.

Abstract: In a method of operating a stationary power plant connected to a power supply network, wherein upon the occurrence of a dynamic network fault in the power supply network, (in particular an electric short-circuit), at least one fault value is ascertained depending on a state value of at least one operating parameter of the power plant. The at least one fault value is associated with at least one component of the power plant, and a maintenance signal for the at least one component of the power plant is output depending on the at least one fault value.

Abstract: In a method of operating a generator connected to a power supply network, in particular a synchronous generator, during a network fault in the power supply network, in particular during an electric short-circuit, electric excitation of the generator is at least temporarily reduced based on the value of at least one operating parameter of the generator prior to the network fault and/or during the network fault.

Abstract: 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.

Abstract: The invention relates to a device and method for controlling a double-fed asynchronous machine (4), preferably for a power plant, in particular for a wind or water power plant. The device includes an indirect converter (6) which is connected on the rotor side to the double-fed asynchronous machine (4). The indirect converter (6) includes a rotor-side converter (20) and a line-side converter (24). At least one control element (8) is provided for controlling the indirect converter (6). At least one software-based and/or hardware-based damping element (40, 46, 48, 120) is provided which has changeable damping characteristics.

Abstract: A system to stabilize power supply includes a turbomachine synchronized to a grid. The system also includes a first controller configured to control field excitation of the turbomachine, and a second controller configured to block operation of the first controller based on a rate of the change in frequency of the grid.

Abstract: A method for the oscillation damping of a drive train in a wind turbine is proposed. The drive train connects a rotor to a generator. Parameter values representing an oscillation of the drive train are calculated and, on the basis of the calculated parameter values, damping forces which counteract the oscillation of the drive train are exerted in a controlled manner on the drive train by a braking device.

Abstract: A device and a method for inhibiting vibration of a superconducting magnetic suspension rotor. The device comprises a rotor cavity housing, lateral coils, a superconducting rotor with a rotor top plane, a copper plate, pole shoes, a z-axial vibration measuring sensor, an x-axial vibration measuring sensor, a y-axial vibration measuring sensor, and a copper ring, the pole shoes having a spherical inner surface and being arranged symmetrically up and down so as to form a rotor cavity; the annular lateral coils being closely adjacent to an outside cylindrical surface of the rotor cavity housing and fixed to the same; the z-axial vibration measuring sensor being fixed to a central region of the copper plate; the x-axial vibration measuring sensor being mounted along an x-coordinate axis and the y-axial vibration measuring sensor mounted on a on the copper ring which is mounted along an equatorial plane of the rotor.

Abstract: A method for damping power oscillation in a power system includes generating synchronized generator speed signals by time stamping a plurality of generator speed signals. The synchronized speed signals are transmitted to a control station for determining power oscillations in the power system. The control station provides damping control signals to a plurality of damping devices based on power oscillations in the power system.

Abstract: The present invention refers to a method of reducing torsional oscillations in the power train of a wind turbine in the event of grid loss. According to the method, after the grid loss, a braking torque is applied to the power train during a period of time and said period of time is determined as a function of the torsional resonance frequency of the power train.

Abstract: A control unit of a system stabilizing device uses a fluctuation detecting block 200 for determining current commands from a system current. A fluctuation detecting unit 300 determines, from an active component Isd of the system current, a common current command Irefd0 which is a fluctuation component of the active component Isd. A first current command creating unit 400 receives as an input the current command Irefd0, and outputs a current command Irefd1 whose signal width is as small as T4 and which instantaneously rises and then gradually decreases. A second current command creating unit 500 receives as an input the current command Irefd0, and outputs a current command Irefd2 which gradually increases for a time T4 and then gradually decreases for a time (T3-T4).

Abstract: Electromechanical arrangements are utilized widely whereby a prime mover in the form of a mechanical assembly such as a gas turbine engine is utilized to drive an electrical machine as an electrical generator. Unfortunately the loads applied to the electrical generator may vary creating oscillation across phases of the electrical generator. Such oscillations generally will be translated to the mechanical assembly in the form of torque oscillations which may cause stressing. Stressing of the mechanical assembly will reduce its life and may alter its performance as well as fuel consumption. By provision of appropriate mechanisms for balancing electrical loads across an electrical machine as well reducing the time decay period for stored charge within an electrical assembly associated with an electrical machine it is possible to reduce torque oscillations as presented to the mechanical assembly and therefore improve its operational performance.

Abstract: A method for controlling the operation of an electromechanical transducer is provided. The method includes (a) determining during a first period of time a first strength of the harmonic operational behavior of the transducer, (b) determining during a second period of time a second strength of the harmonic operational behavior of the transducer, wherein the second period of time is different from the first period of time, (c) calculating a harmonic control signal in response to both the determined first strength of the harmonic operational behavior and the determined second strength of the harmonic operational behavior, (d) generating a modified drive signal based on the calculated harmonic control signal, and (f) supplying the generated modified drive signal to electromagnetic coils of a stator of the transducer. Further, a corresponding control system for controlling the operation of an electromechanical transducer is provided.

Abstract: An electric power generation system has a synchronous machine, a starter excitation source and an exciter field driver. The starter excitation source is connected to the synchronous machine via multiple phase connections, and the exciter field driver is connected to the synchronous machine via a portion of the same phase connections. At least one of the phase connections is connected to each other phase connection via a transient voltage suppressor.

Abstract: A device for damping control of mechanical torsional oscillations of an electrical alternating current generator connected to a multi-phase power supply system, includes a controllable converter of an HVDC installation connected to the power supply system, a measurement and filter device for detection of a frequency-dependent signal in a frequency range of the torsional oscillations of the alternating current generator and a correction apparatus for correction of a control signal for the converter for the HVDC installation. The correction apparatus includes a single phase correction filter for correction of a phase frequency response of the frequency-dependent signal. The control signal is formed by a current nominal value of a current regulator of the converter or a triggering angle of the nominal valve and with the phase correction filter is configured to take a transfer function of the current regulator into account.

Abstract: Utilisation of a number of electrical machines such as generators all driven by a common prime mover, such as a gas turbine engine, are known. However, faults in one phase of one particular electrical machine may cause torque vibration and therefore stressing to mechanical linkages between the electrical machine and the prime mover. By determining torque vibration and then utilising a second electrical machine to introduce an anti-phase torque vibration a substantially balanced and steady torque loading to the mechanical linkages can be achieved.

Abstract: A propulsion arrangement for a marine vessel is disclosed. The propulsion arrangement comprises an engine (12, 14) for propelling the vessel and an electrical machine (26, 28) coupled to the engine. The electrical machine is arranged to supply onboard electrical power for the vessel. A control unit (44) controls the electrical machine such that the electrical machine is selectively operable as a generator or a motor. The control unit and the electrical machine are arranged such that the electrical machine when operating as a motor can supplement the power of the engine while the engine is in operation. In one embodiment, the control unit and the electrical machine are arranged to provide active damping of the engine torque.

Abstract: A system is provided for compensating a power transmission line having one or more non-conventional power generating sources connected to the power transmission line. At least one series compensation circuit is connected to a portion the power transmission line, and at least one damping circuit is connected in parallel with the series compensation circuit. The damping circuit reduces subsynchronous series resonance caused by the series compensation circuit on the power transmission line, and the series compensation circuit compensates the power transmission line.

Abstract: 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.

Abstract: The invention relates to a device and method for controlling a double-fed asynchronous machine (4), preferably for a power plant, in particular for a wind or water power plant. The device includes an indirect converter (6) which is connected on the rotor side to the double-fed asynchronous machine (4). The indirect converter (6) includes a rotor-side converter (20) and a line-side converter (24). At least one control element (8) is provided for controlling the indirect converter (6). At least one software-based and/or hardware-based damping element (40, 46, 48, 120) is provided which has changeable damping characteristics.

Abstract: A power system stabilizer includes: a sensor configured for sensing a signal representative of electromechanical oscillations of the power system; a controller configured for using the sensed signal for generating control signals for damping the electromechanical oscillations; and a damper including a damping converter and a resistor coupled to the damping converter, the damping converter being coupled to the power system through a power bus, the damping converter configured for using the control signals for damping the electro-mechanical oscillations.

Abstract: A torsional protection system and method is provided for protecting a wind turbine from undesired torsional oscillations. The torsional protection system includes a detection processing stage that isolates energy contained within a measured signal to a frequency band of interest. An input to the detection processing stage is obtained from at least one component in the wind turbine. A protection logic stage compares the energy to a threshold level to get an indication of an amount of the energy that is above a predetermined threshold. The torsional content of the signal can be measured and monitored so that if the torsional content exceeds the predetermined threshold for a predetermined time an alarm or trip signal can be generated.

Abstract: When a distortion of an output waveform of an alternating-current generator is improved, an output voltage control apparatus of a generator, which has versatility, is obtained. An output voltage control apparatus of a generator (1), including a generator winding (2) and an excitation winding (3) wound around a stator side, a field winding (5) wound around a rotor (4), and a rectifier (12) for rectifying a current generated by the excitation winding (3) and supplying the rectified current to the field winding (5), the output voltage control apparatus includes a field current drive means (20) for comparing an output voltage generated to the generator winding (2) with a reference wave whose distortion ratio is 0% and flowing a field current to the field winding (5) by adjusting a drive timing of a PWM signal output by a drive unit (24) based on a result of the comparison.

Abstract: A wind turbine hybrid braking system is presented. The system includes a generator coupled to a main shaft of the wind turbine for generating and transmitting power. A mechanical brake is coupled to the main shaft for applying reaction torque upon braking of the wind turbine. The system further includes an electrical braking circuit coupled to the generator for acting in conjunction with the mechanical brake and dissipating active power via controlled switching.

Abstract: Utilisation of a number of electrical machines such as generators all driven by a common prime mover, such as a gas turbine engine, are known. However, faults in one phase of one particular electrical machine may cause torque vibration and therefore stressing to mechanical linkages between the electrical machine and the prime mover. By determining torque vibration and then utilising a second electrical machine to introduce an anti-phase torque vibration a substantially balanced and steady torque loading to the mechanical linkages can be achieved.

Abstract: Electromechanical arrangements are utilised widely whereby a prime mover in the form of a mechanical assembly such as a gas turbine engine is utilised to drive an electrical machine as an electrical generator. Unfortunately the loads applied to the electrical generator may vary creating oscillation across phases of the electrical generator. Such oscillations generally will be translated to the mechanical assembly in the form of torque oscillations which may cause stressing. Stressing of the mechanical assembly will reduce its life and may alter its performance as well as fuel consumption. By provision of appropriate mechanisms for balancing electrical loads across an electrical machine as well reducing the time decay period for stored charge within an electrical assembly associated with an electrical machine it is possible to reduce torque oscillations as presented to the mechanical assembly and therefore improve its operational performance.

Abstract: In an inverter generator having an engine generator unit generating alternating current, a converter converting the alternating current to direct current, an inverter that converts the direct current to alternating current, an inverter driver that drives switching elements with a PWM signal generated using a reference sine wave of a desired output voltage waveform and a carrier and makes the alternating current to the alternating current of a predetermined frequency, the alternating current supplied to an electrical load is detected, gains Gn (n: 2, 3, 4, 5, 6, . . . m) of n-th harmonics of the reference sine wave and amplitudes An are calculated from the detected current, and the reference sine wave is corrected by a sum obtained by the calculated gains and amplitudes. With this, the reference sine wave is accurately corrected to reliably remove harmonic distortion components from the output voltage waveform.

Abstract: To estimate a fluctuation component of the torque generated at the motor accurately, a motor control device (3) which controls a motor with a stator having armature winding and a rotor having a permanent magnet is provided to include a torque fluctuation component estimation unit for estimating a torque fluctuation component generated at the motor based on flux-linkage of the armature winding and an armature current that flows the armature winding. The torque fluctuation component estimation unit estimates the torque fluctuation component, (Trp) based on an inner product (Fd·id+Fq·iq) of a flux-linkage vector which is a vectorial representation of the flux-linkage and a current vector which is a vectorial representation of the armature current.

Abstract: Methods and systems are disclosed for reducing alternating current ripples in direct current electrical power generation systems with one or more regulated permanent magnet machines. Ripple suppression is achieved, in one aspect, by modulating the control current of a regulated permanent magnet machine.

Abstract: A method and a damping device are proposed for damping a torsional oscillation in a rotating drive train. Arranged on the drive train is an electrical machine (13), which is connected to an electrical multipole (31). A damping torque is generated in the electrical machine (13) by an electrical damping member connected to the electrical machine (13). It is proposed that the damping torque has a predetermined damping frequency and is antiphase to the angular velocity of the torsional oscillation.

Abstract: A power system stabilizer includes: a sensor configured for sensing a signal representative of electromechanical oscillations of the power system; a controller configured for using the sensed signal for generating control signals for damping the electromechanical oscillations; and a damper including a damping converter and a resistor coupled to the damping converter, the damping converter being coupled to the power system through a power bus, the damping converter configured for using the control signals for damping the electromechanical oscillations.

Abstract: An electromechanical power transfer system that transfers power between a prime mover and a direct current (DC) electrical system, comprises: a permanent magnet machine (PMM) that has a permanent magnet (PM) rotor coupled to the prime mover, a stator with a multiphase alternating current (AC) winding coupled to an AC bus and a control coil with a winding that has a configuration to generate a magnetic field with flux that varies the reactance of the stator winding with the application of control coil current; a control coil current sensor for generating a control coil current signal that is representative of the level of electrical current in the control coil; an electrical current sensor for generating a DC bus current signal that is representative of the level of DC current through the DC bus; an electrical potential sensor for generating a DC bus potential signal that is representative of the level of DC potential on the DC bus; a fixed pattern active rectifier and inverter system coupled between the AC bu

Abstract: An electrical power generation system is provided, and a method of reducing undesired currents therein. The method includes the steps of delivering current via at least one variable frequency switching means, and adjusting a switching frequency of the at least one variable frequency switching means based on the power output of the system. The system may further include an electronic controller having a control algorithm recorded thereon, the control algorithm including means for adjusting the variable frequency switching means based on a power output of the system.

Abstract: A power electronic based DR (distributed resource e.g., a UPS (uninterrupted power supply), Fuel Cell or Microturbine) is controlled to emulate a voltage source behind an impedance and behave as a power system stabilizer. The impedance in the DR is emulated and an estimate of impedance at the power/electronic interface is derived and applied to the control of the DR in a manner wherein the power and voltage swings on systems (loads) that otherwise would have difficulty with dynamic loads, are stabilized. Damping and synchronizing power are provided measuring only voltage, current and frequency at the interface between the DR and the load. The DR may include some energy storage.

Abstract: Magnetic bodies for reducing electromagnetic wave noises are mounted to a battery voltage supplying terminal for supplying of an electric source power for the operation of circuits to an IC chip of a regulator or an internal electric source line for connection of the terminal to the regulator chip. The magnetic bodies are attached to an IG ON terminal for inputting into the regulator chip a voltage signal caused by opening and closing of an ignition switch or to an IG ON detection line for connection of the terminal to the regulator chip. A bypass capacitor is connected to a battery voltage detecting terminal for inputting a change of battery voltage into the regulator chip, or to an internal battery voltage detection line for connection of the terminal to a switching transistor control circuit unit.

Abstract: A microcomputer malfunction preventive apparatus that halts supplying of a clock signal to a microcomputer when fluctuations in a supply voltage deviate from an acceptable range, and resumes supplying of the clock signal to the microcomputer when the fluctuations return to the acceptable range.

Abstract: Devices, systems, methods and kits are provided for use in determining the concentration of chemical and biochemical components in aqueous fluids. The subject devices include test strips which define a longitudinal axis and include a distal edge configured for insertion into a measurement instrument and having an alignment notch formed in the distal edge for engagement with an alignment member of the measurement instrument. The alignment notch has opposing edges wherein at least a portion of the opposing edges is in substantially parallel relation to the longitudinal axis. In using the subject devices, the devices are inserted into a measurement instrument having an alignment pin. When operatively engaged with the alignment pin, the notch serves to maintain the device in a substantially motionless position. The invention is useful in a variety of applications, particularly in the determination of blood glucose concentrations.

Abstract: A power plant includes a gas turbine coupled to an electric generator. The electric generator can be connected to a high-voltage network through a generator switch and can be operated as a motor for the start-up of the gas turbine. The electric generator can also be connected to a static starting device for the run-up of the gas turbine. The static starting device is connected to a medium-voltage network which is provided for the auxiliary service of the power plant. The auxiliary voltage, provided in another way, of the medium-voltage network, produces a variable supply voltage for the generator operated as a motor. In such a plant, reduced circuit complexity is achieved by the fact that the static starting device is designed in such a way or can be activated in such a way that, after the run-up of the gas turbine, the static starting device itself produces the auxiliary voltage of the medium-voltage network from the voltage delivered by the generator.

Abstract: A system for controlling reactive currents in a generator is provided. A control system receives current and voltage feedback from the generator. The control system determines a phase angle based on the current and voltage feedback. The control system determines a compensation signal corresponding to the phase angle and current. The control system modifies a generator excitation signal based on the compensation signal and a bi-linear transformation technique.

Abstract: A charging system has an alternator, a battery, and a controlled rectifier bridge between the alternator and the battery. The controlled rectifier bridge has controllable elements. A controller is provided wherein the controller controls (a) the duty cycle of the alternator field winding and (b) the switching in the controllable elements to control the phase advance angle. By utilizing a half-wave controlled rectifier bridge and three controllable elements, power output can be increased at a low overall cost. In another embodiment, the controller determines switching points for the controllable elements through a third harmonic extraction device which employs a neural network for determining the zero crossings of the third harmonic voltage obtained from a single phase voltage.

Abstract: A marine power distribution arrangement utilizes generators driven at standard or higher than normal speeds and/or having a number of poles to produce electric power at a standard 50/60 Hz frequency or substantially higher than the standard 50/60 Hz frequency, such as 400 Hz. Each generator is a multi-phase, multi-circuit generator supplying isolated outputs on a plurality of lines to a propulsion power converter having isolated inputs to provide variable frequency, variable voltage power to a ship propulsion motor and to a service power converter to provide ship service power at a standard AC frequency or DC and at standard voltage for a service load. With this arrangement, power conversion transformers can, for the most part, be eliminated, thereby reducing the size and weight of the distribution system.

Abstract: A generator transfer function regulator incorporating two control loops. The first control loop produces a first generator excitation control signal (U) which varies to compensate for variations in the magnitude of the generator output voltage (V.sub.1) . The second generator loop produces a second generator excitation control signal (U.sub.e) which varies so as to maintain substantially constant the response of the generator system to variations in the generator output. The two control signals are combined and applied to a conventional generator exciter circuit (2). As a result, the generator terminal voltage (V.sub.1) control performance achieved by the AVR under open circuit conditions is effectively maintained when the generator is loaded over its range of operation, irrespective of the power system which the generator feeds.

Abstract: A control signal processor effects control to permit or inhibit the passage of an input signal, by a logic operation, based on a ratio of input and output signals of a filter circuit having a double differentiation function characteristic.

Abstract: A regulator for an alternator installed in a vehicle has a switching circuit in which a field current limiting transistor interruptibly controls a flow of current to a field coil of the alternator. A battery output voltage detection terminal is connected to the battery, and an alternator output voltage terminal is connected to the alternator. A diode connected to the battery output voltage detection terminal has a reverse recovery time of 20 ns-20 .mu.s, and a resistor is connected between the diode and the alternator output voltage terminal. A control circuit controls the switching circuit, in order to regulate the voltage at a connection point of the diode and the resistor so as to keep the voltage constant, and an alarm generating circuit illuminates a charge indicator lamp if the voltage at a junction of said diode and said resistor exceeds a reference voltage.

Abstract: A method for detecting islanding operation of a rotating-machine type dispersed generator. The dispersed generator is interconnected with a main electric source through a circuit breaker to constitute an electric power system. The estimating method is implemented as follows: (a) changing electric power of the electric power system; (b) detecting frequency component of the electric power; and (c) deciding that an islanding operation of the dispersed generator is executed if the change of the frequency component becomes greater than a predetermined value. With this method, it becomes possible to detect the islanding operation of the dispersed generator even if the power flow at the interconnecting circuit breaker is generally zero.

Abstract: A charge control system for an internal combustion engine which is capable of suppressing electromagnetic noise due to a control signal to a generator, and which prevents overcharging a battery even if an input terminal receiving the control signal is grounded. The charge control system is composed of a generator 1 driven by an engine of a motor vehicle and a battery 4 charged with the output of the generator 1. Also included in the system is a computer unit 2 comprising a microcomputer CPU for calculating a target voltage Vreg on the basis of the operational states of the motor vehicle for comparison with a battery voltage Vb so as to output a drive signal in accordance with the comparison result. This drive signal operates a transistor Tr, incorporated into the generator, to control a field current 1f of the generator 1 so that the quantity of the power generation of the generator 1 increases and decreases to control the quantity of the charge to the battery 4.

Abstract: A system information input means takes in system information and a system state determining means determines states of the system. A component operation state determination means determines operation states of system stabilizing components. A control plan deciding means decides a control plan of the system in consideration of operation states of the system and the system stabilizing components. In deciding the control plan, a swing mode analyzing means firstly analyzes the swing mode at each place of the system on the basis of waveforms of time domain response simulations. Then, a control allotment setting means determines control allotment for each of the system stabilizing components based on the mode analysis and a control parameter setting means control sets the control parameters of each of the system stabilizing components. If plural control plans are obtained, the optimal one is selected based on eigenvalues of dynamics of the system or by evaluating time domain system responses by simulation method.