Abstract: A load control device may control power delivered from a power source, such as an alternating-current (AC) power source, to at least two electrical loads, such as a lighting load and a motor load. The load control device may include multiple load control circuit, such as a dimmer circuit and a motor drive circuit, for controlling the power delivered to the lighting load and the motor load, respectively. The load control device may adjust the rotational speed of the motor load in a manner so as to minimize acoustic noise generated by the load control device and reduce the amount of time required to adjust the rotational speed of the motor load. The load control device may remain powered when one of the electrical loads (e.g., the lighting load) has been removed (e.g., electrically disconnected or uninstalled) and/or has failed in an open state (has “burnt out” or “blown out”).

Abstract: Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers.

Abstract: A power supply system includes a plurality of power conversion devices, a plurality of breakers, and a controller. The plurality of breakers are respectively connected to the plurality of power conversion devices and configured to perform switching of an electrical connection between the power conversion device and a power system, wherein the breaker switches an ON state and an OFF state. The controller is configured to control the breakers and switch connection states of the plurality of power conversion devices are switched, and the controller being configured to determine whether or not the connected breaker is in an ON state and electrically conducted to the power system and the number of the power conversion devices in a standby state reaches a predetermined number.

Abstract: An uninterruptible power supply (UPS) system includes an AC output, an inverter coupled to the AC output and configured to provide power at the AC output, and a switch configured to selectively couple a generator (e.g., an engine-generator set) to the AC output. The system further includes a control circuit configured to variably modulate the switch to gradually increase control power flow from the generator to the AC output while causing the inverter to concurrently provide power to the AC output. The switch may be a static switch that includes at least one silicon controlled rectifier (SCR), and the control circuit may be configured to control a conduction interval of the at least one SCR to control power flow from the generator to the AC output.

Abstract: Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers.

Abstract: A hybrid energy storage system is configured to control pulsed power. A first dynamo-electric machine is coupled to an inertial energy storage device and has multiple input stator windings configured to accept input power from a source. A polyphase output stator winding is configured to deliver electric power having a first response time to a DC bus. A secondary energy storage system is coupled to the DC bus and is configured to convert its stored energy to electric power in a bidirectional manner. A second dynamo-electric machine has an input stator winding and at least one polyphase output stator winding coupled to a converter, the converter coupled to a DC output. A polyphase boost exciter is configured to derive energy from the DC bus and excite the second machine input stator winding, wherein the second machine is configured to be excited at a faster rate than the first response time of the first machine.

Abstract: Modular dual power sources and corresponding systems include a common hybrid energy storage system, a high frequency DC-DC converter coupled between the common hybrid energy storage system, and an ultra-capacitor module for starting up a generator, and a two-level inverter coupled to the common hybrid energy storage system to provide power in case of an interruption in power supplied by a utility supply. The hybrid energy storage system includes an ultra-capacitor module and a battery module. A fast charger is coupled to the hybrid energy storage system to quickly charge the ultra-capacitor module and the battery module, which, in turn, charge the ultra-capacitor module for starting up a generator via a high frequency DC-DC converter. High frequency transformers are used to magnetically isolate electrical noise of the generator and UPS functions and operate independently. The modular dual power sources can be connected in parallel to provide large MW output power.

Abstract: An uninterruptible electric power system comprises a main power supply unit, an uninterruptible power supply unit receiving AC commercial power from the main power supply unit, and a slave power supply unit. The uninterruptible power supply unit converts the AC commercial power to stable AC power. The slave power supply unit is connected to the uninterruptible power supply unit. The slave power supply unit comprises a slave static transfer switch, which comprises a first input terminal connected to the uninterruptible power supply unit to receive the stable AC power, a second input terminal receiving the AC commercial power, and an output terminal configured to connect, when the uninterruptible power supply unit is in normal operation, to the first input terminal to receive the stable AC power, and connect, when the uninterruptible power supply unit operates abnormally, to the second input terminal to receive the AC commercial power.

Abstract: A power generation system is provided. The system includes a prime mover for transforming a first energy to a second energy. The system also includes an induction generator operatively coupled to the prime mover and configured to generate electrical power using the second energy. The system further includes an inverter electrically coupled to the induction generator for controlling a terminal voltage of the induction generator during a grid-loss condition. The system also includes a power dissipating device operatively coupled to the inverter for dissipating power generated by the induction generator during the grid-loss condition.

Abstract: A hybrid energy storage system is configured to control pulsed power. A first dynamo-electric machine is coupled to an inertial energy storage device and has multiple input stator windings configured to accept input power from a source. A polyphase output stator winding is configured to deliver electric power having a first response time to a DC bus. A secondary energy storage system is coupled to the DC bus and is configured to convert its stored energy to electric power in a bidirectional manner. A second dynamo-electric machine has an input stator winding and at least one polyphase output stator winding coupled to a converter, the converter coupled to a DC output. A polyphase boost exciter is configured to derive energy from the DC bus and excite the second machine input stator winding, wherein the second machine is configured to be excited at a faster rate than the first response time of the first machine.

Abstract: According to one aspect, embodiments of the invention provide a method of operating a UPS system having a first UPS and a second UPS, the method comprising powering on the first UPS, receiving power from a first input power source coupled to an input of the first UPS, providing power to a load coupled to an output of the first UPS, adjusting the power provided to the load by the first UPS in response to power characteristics of the first UPS and power characteristics of the second UPS.

Abstract: An energy storage system is disclosed. The system can supply DC power from a battery to a DC load or from the DC load to the battery without inverting an AC power to the DC power.

Abstract: A hybrid power system is disclosed. The hybrid power system may include a primary power source configured to provide a primary power, and an energy storage device coupled to the primary power source, the energy storage device configured to store excess primary power provided by the primary power source. The hybrid power system may further include a variable speed genset, the variable speed genset including a secondary power source configured to operate at a variable rotor speed to provide a secondary power responsive to power requirements of a load. The hybrid power system may also include a central controller communicatively coupled to the primary power source, the energy storage device, and the variable speed genset, the central controller configured to control the primary power source, the energy storage device, and the variable speed genset based on the power requirements of the load.

Abstract: A control system, method, and device for managing variable power sources in DC power systems, such as photovoltaic (PV) systems. An electrical component can be configured to condition power from a photovoltaic (PV) panel such that current is drawn from the PV panel at a peak power continuously, at all times, or irrespective of current flux.

Abstract: A method and apparatus for indicating a disconnection within a Distributed Generator (DG). In one embodiment, the apparatus comprises an alarm module electrically coupled to a conductive portion of a component within the DG, wherein the conductive portion is grounded via a ground rod system, and wherein the alarm module (i) is further coupled to a ground line, (ii) couples a monitoring current to the conductive portion, (iii) monitors flow of the monitoring current to determine a change in the flow, and (iv) generates, as a result of the change in the flow, a notification of the disconnection.

Abstract: Uninterruptible Power Supply system comprising motor generator means for conditioning electric power; backup generator means including an internal combustion engine having electrically driven starter, providing backup electric power; electrical switch means, said switch means being electrically connected to power mains and to the backup generator means' electrical output and the motor generator means' electrical input for selectively switching power from the electric means and the backup generator to the motor generator means; starter switch means electrically connected to the motor generator means' output and electrically connected to the input of the starter system of the backup generator means, for switchably connecting the motor generator means' electrical output to the starter system means' input.

Abstract: A control methodology for an engine-driven electric machine of a hybrid vehicle electrical system for enabling continued operation of the vehicle electrical system under failure mode conditions that require or result in disconnection of the battery pack from the electrical system. At the onset of a fault condition requiring battery disconnection, the electric machine is controlled to drive the battery pack current toward zero before disconnecting the battery pack. Once the battery pack is disconnected, whether by relay or fuse, the electric machine is controlled to maintain the bus voltage of the electrical system at a specified value. In both operating modes, the electric machine is controlled based on a synchronous vector current command that is determined directly as a function of the control objective (zero battery pack current or maintaining bus voltage) for improved response time compared to a traditional torque-based control.

Abstract: The present invention relates to an alternating-current power supply device which can improve a power factor of an alternating-current load, realizes low cost and miniaturization, and recovers magnetic energy. The alternating-current power supply device includes a bridge circuit composed of four reverse conducting semiconductor switches, a capacitor that is connected between direct-current terminals of the bridge circuit and absorbs the magnetic energy at the time of cutting off the current, an alternating-current voltage source that is connected to the induction load in series and is inserted between alternating-current terminals of the bridge circuit, and a control circuit that gives a control signal to gates of the respective reverse conducting semiconductor switches and controls on/off states of the respective reverse conducting semiconductor switches.

Abstract: The present invention provides a method, computer program product, and apparatus and control system and method for providing substantially uninterrupted power to a load. The apparatus includes a control system coupled with an electrical power storage subsystem and a electrical power generator. The control system is configured to provide a plurality of modes of operation including at least a static compensator (STATCOM) mode, an uninterruptible power supply (UPS) mode and a generator mode (gen set), and to control transitions between each of the plurality of modes. In one embodiment, the control system is an integrated closed loop control system that includes a current control system and a voltage control system. The apparatus is capable of operating at least two of the plurality of modes simultaneously, including ramping the gen set mode up and simultaneously ramping the UPS mode down as the gen set mode is ramped down.

Abstract: A vehicle electrical system includes at least one battery, at least one fan and a device for detecting a critical state in the vehicle electrical system. The fan is activated when a critical state of the vehicle electrical system is detected. In this context, use is made of the fan's ability to store mechanical energy in the form of inertias. The fan operates in a regenerative manner and electrically feeds the mechanically stored energy back into the on-board electrical system.

Abstract: A reconfigurable power system that includes a gas turbine, flywheel, a first electric machine coupled to the gas turbine, a second electric machine coupled to the flywheel, the first and second electric machines being substantially similar in configuration, a first power device for coupling power from the first electric machine to a power grid, a second power device coupled to the second electric machine for driving the flywheel and coupling power from the second electric machine to the power grid, and a switch for coupling either the power generated by the first electric machine or the second electric machine to the grid.

Abstract: A power generation system includes a first unit power generation system having a storage battery, a second unit power generation system having no storage battery and a controller, at a time of starting up of the power generation system, the controller first starts up the first unit power generation system and then starts up the second unit power generation system having no storage battery by supplying electric power generated by the first unit power generation system to the second unit power generation system.

Abstract: Apparatus and associated method and computer program products involve a highly efficient uninterruptible power distribution architecture to support modular processing units. As an illustrative example, a modular processing unit includes an integrated uninterruptible power system in which a PFC-boost AC-to-DC conversion occurs between the utility AC grid and the processing circuit (e.g., microprocessor) loads. In an illustrative data center facility, a power distribution architecture includes a modular array of rack-mountable processing units, each of which has processing circuitry to handle network-related processing tasks. Associated with each modular processing unit is an integrated uninterruptible power supply (UPS) to supply operating power to the network processing circuitry. Each UPS includes a battery selectively connectable across a DC bus, and a AC-to-DC rectifier that converts an AC input voltage to a single output voltage on the DC bus.

Abstract: An Automatic Transfer Switch (ATS) having a switch configured to connect one of two sources to a load, a mechanical drive, an actuator, and a solid state control relay is disclosed. The mechanical drive is configured to drive the switch between a first position and a second position, the first position connecting the switch to the first source, and the second position connecting the switch to the second source. The actuator is in mechanical communication with the mechanical drive to cause the mechanical drive to move on command. The solid state control relay is responsive to an external signal and productive of a control signal, wherein the actuator is responsive to the control signal to cause the mechanical drive to move.

Abstract: A wind powered turbine with low voltage ride-through capability. An inverter is connected to the output of a turbine generator. The generator output is conditioned by the inverter resulting in an output voltage and current at a frequency and phase angle appropriate for transmission to a three-phase utility grid. A frequency and phase angle sensor is connected to the utility grid operative during a fault on the grid. A control system is connected to the sensor and to the inverter. The control system output is a current command signal enabling the inverter to put out a current waveform, which is of the same phase and frequency as detected by the sensor. The control system synthesizes current waveform templates for all three-phases based on a sensed voltage on one phase and transmits currents to all three-phases of the electrical system based on the synthesized current waveforms.

Abstract: The invention relates to an energy storing method and apparatus for use by end-users of energy, such as commercial property owners and operators. The system differs from past systems, insofar as it is not intended to be used by and in connection with energy suppliers, such as large utility and power supply plants and grids. The system preferably relates to the manner in which an end-user of energy can implement energy and costs savings, by using energy storage and time-shifting methods, to control and regulate the consumption of energy in a manner that achieves a cost savings over a period of time.

Abstract: Several embodiments of an uninterruptible power supply (UPS) system, which system provides highly reliable output power to a load using a slip-ring induction machine and a flywheel combination, are disclosed as well as methods relating thereto. In a preferred embodiment, the UPS system comprises a back-up power source, e.g., an engine and generator, and a slip-ring, or wound-rotor, induction motor and flywheel combination, which are in parallel to a primary power source, e.g., a utility grid. During normal operation of the UPS, the primary power source supplies alternating current and voltage to the load and the UPS compensates for voltage drop across the isolating inductor. Moreover, the primary power source keeps the slip-ring induction machine and flywheel in an excited state, i.e., the rotor of the slip-ring induction machine, the shaft of which is shared by the flywheel, is excited above normal synchronous speed.

Abstract: The position-controlled stopping of rotating components of shaftless drive mechanisms, in the case of a loss of voltage, is accomplished by the provision of an external connectable network. That external connectable network supplies the process power which is missing due to a loss of rotational power in the event of a voltage loss.

Abstract: A portable power supply includes an engine-driven generator that generates a first AC power. A rectifier rectifies the first AC power to a first DC power. A DC/DC converter converts a second DC power from a storage unit to a third DC power. A controller selectively enables one or both of the rectifier and the DC/DC converter to provide one or both of the first DC power and the third DC power to the input of an inverter. The inverter converts the DC power at its input to a second AC power. Alternatively, the power supply advantageously includes a second generator and a second rectifier. The outputs of the two rectifiers are summed and the sum of the two outputs is provided as an input the inverter to extend the range over which a constant second AC power can be provided.

Abstract: A flywheel energy storage device, for producing electrical power in an allowable range of operating voltages for an output load, includes an energy storage flywheel supported for rotation on a bearing system, and a brushless motor and a brushless permanent magnet generator for accelerating and decelerating the flywheel for storing and retrieving energy. The generator has a multiplicity of windings for producing output power from the generator by a magnetic coupling that provides output power DC voltage. An out regulator circuit provides variable DC voltage that is maintained within the allowable range for connected loads as the flywheel slows during discharging. The output regulator circuit includes electronic switches for switching connections of the windings to change the number of windings connected to the output to maintain output power DC voltage within the allowable range. The switching occurs less than once per every 10 revolutions of the flywheel.

Abstract: A power controller for controlling an engine-driven generator includes a high voltage DC bus interconnecting various power modules. In electrical communication with the DC bus are: a bi-directional DC-DC converter constructed to transfer electrical power from the DC bus to a battery to charge the battery, and from the battery to the DC bus; a rectifier constructed to rectify electrical power from the generator and to supply the rectified power to the DC bus; an inverter constructed to convert DC bus electrical power to AC electrical power and to supply the AC power to an output connector; and an AC-DC constructed to convert AC electrical power, supplied via an input connector, to DC bus electrical power. The controller may be employed in a power supply on a mobile vehicle or boat, for example. The power modules of the controller cooperate in various combinations to provide a wide variety of power transfer functions.

Abstract: An exemplary embodiment of the invention is a power system including a first power source, a first DC bus coupled to the first power source and a second DC bus coupled to the first power source. A power conditioning device is coupled to the first DC bus and the second DC bus. A load receives power from the power conditioning device.

Abstract: An improved UPS/CPS system employs a high-efficiency uninterrupted power supply function integrated with an engine-generator set that combines both short term protection against momentary power interruptions with longer term power generation. Feedback from a controller provides for improved voltage regulation during abrupt load changes and flexibility of application. A number of features and operating modes are disclosed. In one embodiment, the system is useful as a kit to retrofit existing backup power facilities.

Abstract: An electrical system for use in isolation, the electrical system comprising a main engine (14), such as a gas turbine or a diesel engine, a generator (13) driven by the main engine (14) for generating a first alternating voltage (19), a first rectifier unit (12) for converting the first alternating voltage (19) generated by the generator (13) into a direct voltage on a DC bus (18), and at least one inverter unit (10, 15) for converting the direct voltage of the DC bus (18) into a second alternating voltage (20). The generator (13) driven by the main engine (14) for generating the first alternating voltage (19) is an asynchronous machine coupled directly to the shaft of the main engine (14), and the first rectifier unit (12) also comprises an inverter part for converting the direct voltage of the DC bus (18) into an alternating voltage with an adjustable frequency to said asynchronous machine (13) so as to use the machine as a motor.

Abstract: An ON-LINE uninterrupted power supply (UPS) of this invention serving as a long term high quality power supply for web, telecommunication, security system, etc is characterized in detecting a ring signal from far end for ON/OFF control of an output power and in permitting omni-range input civil power to avoid any unstable output power.

Abstract: The present invention relates to a control system of an auxiliary power system for a hybrid electric vehicle in which a circuit of the control system of the auxiliary power system is constructed by a digital method. The control system has a function for monitoring a battery charging state and a function for controlling an engine at a constant speed. The auxiliary power system for a hybrid electric vehicle includes an engine, a generator, a battery, and a load. The control system includes a rectifier, a first shunt circuit, a smoothing circuit, a contactor, a main control circuit portion, an engine constant-speed control portion, an auxiliary battery, DC/DC converter, a battery charge voltage monitoring portion, a control state display portion, and a second shunt circuit.

Abstract: In order to provide a system for stabilizing a power supply system comprising a choke, which connects the power supply system to a mains power feed, a converter system connected to the power supply system and having a converter machine with a rotor and at least one three-phase winding, which is in a position to stabilize the voltage in the power supply system to a specific value it is suggested that the converter system comprise a flywheel storage means with a synchronous machine and a flywheel coupled thereto, that the converter system have a static converter system, with which the flywheel storage means can be coupled to the converter machine such that the flywheel storage means can draw power from the converter machine or supply power to it, and that a control be provided which detects the voltage of the power supply system and controls the static converter system such that the converter machine stabilizes the voltage of the power supply system to a predeterminable value by drawing or supplying power.

Abstract: A power supply system and method provides for smooth transitions between a utility power, transitory instantaneous power, and backup power in the event of a utility power failure of a utility supplying power to a load. As the utility power weakens due to a failure of the normal utility power supply, a synchronous machine becomes immediately a generator and supplies the required instantaneous power to the load. In order to maintain a constant speed on the synchronous machine, a high speed flywheel rotating faster than the synchronous machine provide kinetic energy that is magnetically coupled to the synchronous machine through an electromagnetic clutch to provide the synchronous machine with the required energy until the utility recovers from its failure. The control means enable smooth transitions by phase synchronization when transiting between utility power, instantaneous power and backup power.

Abstract: An uninterruptible power supply (UPS) provides improved reliability by extending the useful life of a bank of batteries that provide backup power to the UPS in the event of an extended power outage. In the preferred embodiment, battery life is extended by switchably isolating the bank of batteries from the DC buss that is coupled to the critical load. Backup power for short duration outages, on the order of about ten seconds or less, is provided by a flywheel energy storage unit. Once the outage becomes extended, the isolation circuit is triggered to electrically connect the bank of batteries directly to the DC buss. In this manner, the bank of batteries does not experience AC ripple or the common, short duration outages that would otherwise cause the batteries to experience a discharge/recharge cycle.

Abstract: An uninterruptable power supply, operating normally under power supplied by a utility, has a main motor, a smaller induction motor, and a mechanical load such as a generator coaxially coupled together. A battery is connected to the smaller induction motor through an inverter. The induction motor is normally idled at a frequency lower than that of the utility, and therefore operates as an induction generator which is used to charge the battery through the inverter. Upon utility failure, the utility line is disconnected and the induction motor is powered by the battery through the inverter. The frequency of the inverter may be increased to maintain the rotational speed of the system at a nearly constant level.

Abstract: A craft, such as an aircraft, landcraft, watercraft, space craft, or the like, is provided with a power transfer system which ensures an uninterrupted supply of electrical power to on board electrical equipment during normal switching from one power supply to another i.e., switching which is not due to system failure, which switching may be initiated either manually by the pilot, or automatically by the system. The power transfer system can be used with separate DC power sources, and includes a split bus assembly which ensures a continuous electrical equipment supply from a first operating power source until after a second different power source has been energized and begun to supply operating power to the electrical equipment in question. Once the second power supply is brought on line, the first power supply can be shut down. The system can be used when switching between different on board power supplies or when switching between on board and external power supplies.

Abstract: A battery-less uninterruptable sequel power supply that converts mechanical rotation generated by a local power source to electrical power in the event of commercial line power distortion or failure is provided. The uninterruptable sequel power supply uses a voltage and frequency-tolerant rectifier-inverter combination that converts the decaying output of a de-accelerating synchronous alternating current machine to a stable alternating current voltage for driving a critical load. In the arrangement of the invention, there is no need to maintain rotary velocity of the synchronous alternating current machine during the transitory period between fault detection and connection of a prime mover.

Abstract: An UPS (uninterruptible power system) includes an UPS power conditioning unit that provides conditioned AC power to a critical load. The UPS power conditioning unit includes a variable speed drive that operates in response to AC utility power or to a standby DC input by providing a motor drive signal. The UPS power conditioning unit further includes a motor-generator that operates in response to the motor drive output by providing the conditioned AC power to the critical load. In response to an outage in the utility AC power, standby DC power is provided by a standby DC power source that includes a variable speed drive and a flywheel motor-generator connected to the variable speed drive. Both the UPS power conditioning unit and the standby DC power source are initially operated in response to the utility AC power, the flywheel motor-generator storing kinetic energy in a rotating flywheel.

Abstract: The system ensures electric feed for which purpose it has an alternating current motor (1) coupled to an alternator (2) which is coupled to a hydraulic motor (8) which in turn is coupled to a diesel engine (7.)The alternating current motor is coupled by means of a clutch (6) to a high pressure pump (5.)All the elements are governed by a control circuit (4) so that in the absence of network, it simultaneously drives the diesel engine (7) and the hydraulic motor (8) the latter initially maintaining the angular speed of the alternator, until the diesel engine (7) attains its normal working conditions; as of when it is mechanically coupled to the alternator (2), the hydraulic motor (8) remaining turned off.The high pressure pump is capable of being directly coupled to the diesel engine (7) with which the hydraulic motor (8) is the one which maintains the angular speed of the alternator (2) at all times.

Abstract: An auxiliary power supply system includes an internal combustion engine driving an alternator the output of which is rectified and supplied to DC bus lines across which a storage battery is connected. The DC bus lines may supply a consuming device such as an uninterruptible power supply or telecommunications system. The voltage across the bus lines is sensed and when the voltage drops below a selected value, indicating that the consuming devices is drawing power from the battery beyond a desired limit, the engine is turned on for a period of time to warm it up, during which the power from the generator is not supplied to the DC bus lines. Thereafter, the generator supplies power to the DC bus lines to supply the consuming device and partially recharge the battery until the consuming device is no longer drawing power, after which the engine is shut off.

Abstract: Each of at least two asynchronous generators connected to a common electrical load for uninterruptibility of the power supply is driven by a corresponding one of at least two drives in such a way that when any one of the generators is driven above synchronous speed by a slip fraction while its stator is electrically excited, its shaft mechanical power is converted to electrical output power at its output terminal. A control circuit is connected to the load, coupled to the output terminals of the generators and connected to the input terminals of the generators and provides an excitation voltage and controls the phase of the excitation voltage of each of the generators with respect to the load voltage. This controls the slip fraction of each of the generators loosely whereby load current from any source is completely controlled.

Abstract: An uninterruptible power source includes an induction motor/generator assembly and a continuously on line variable speed drive connected to inductively accelerate the motor/generator assembly to near rated speed. When the motor/generator assembly reaches rated speed, the motor/generator is switched to synchronous operation, while still under control of the variable speed drive. The variable speed drive includes slip compensation to maintain the motor at rated speed. The variable speed drive operates in response to a utility power signal and to a standby power signal. When the utility power signal fails, operation of the drive is maintained, without interruption, by the standby power.

Abstract: An uninterruptible power source is disclosed and claimed which includes a synchronous motor/generator assembly and a continuously on line variable speed drive connected to inductively accelerate the motor/generator assembly to near synchronous speed. When the motor/generator assembly reaches near synchronous speed, the motor/generator is switched to synchronous operation, while still under control of the variable speed drive. The variable speed drive is connected to maintain synchronicity with the motor/generator during acceleration. Resultantly, when switchover to synchronous operation occurs, no synchronization of the motor/generator to the variable speed drive is required. The variable speed drive operates in response to a utility power signal and to a standby power signal. When the utility power signal fails, operation of the drive is maintained, without interruption, by the standby power.

Abstract: An uninterruptible rotating power supply incorporates a sensor of motion and distortion of a stator during interruptions of normal power supply acting on the stator within a synchronous motor, which normally rotates an alternator supplying power to the electric load. When a distortion (unacceptable normal power supply) is sensed, transient power is supplied by a flywheel and hydraulic motor driven by hydraulic fluid stored under pressure in a reservoir. Long term emergency power is supplied by a diesel engine driving the generator or hydraulic pump. The dual supply of transient power allows redundancy for large amperage critical applications or downsizing of flywheel to minimum levels in less critical applications or where a portion of the load is not critical.

Abstract: In a system for detecting an angle of a joint coupled through a reduction mechanism to a drive motor, an absolute type rotation angle detector and an incremental-type rotation number detector are coupled to the motor for detecting the rotational angle and the rotation number of the motor, respectively. The detected rotational angle and the detected rotation number are used to calculate the rotational angle of the joint. The incremental-type rotation number detector is provided with a battery for energization during interruption of a power supply.