Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/04—Introducing corrections for particular operating conditions
  • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
  • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
  • F02B37/04—Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump
  • F02B37/10—Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump at least one pump being alternatively or simultaneously driven by exhaust and other drive, e.g. by pressurised fluid from a reservoir or an engine-driven pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B39/00—Component parts, details, or accessories relating to, driven charging or scavenging pumps, not provided for in groups F02B33/00 - F02B37/00
  • F02B39/02—Drives of pumps; Varying pump drive gear ratio
  • F02B39/08—Non-mechanical drives, e.g. fluid drives having variable gear ratio
  • F02B39/10—Non-mechanical drives, e.g. fluid drives having variable gear ratio electric
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D29/00—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto
  • F02D29/06—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto peculiar to engines driving electric generators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0002—Controlling intake air
  • F02D41/0007—Controlling intake air for control of turbo-charged or super-charged engines
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
  • H02P9/04—Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
  • H02P9/08—Control of generator circuit during starting or stopping of driving means, e.g. for initiating excitation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/18—Control of the engine output torque
  • F02D2250/24—Control of the engine output torque by using an external load, e.g. a generator
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D25/00—Controlling two or more co-operating engines
  • F02D25/02—Controlling two or more co-operating engines to synchronise speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
  • F02N11/00—Starting of engines by means of electric motors
  • F02N11/04—Starting of engines by means of electric motors the motors being associated with current generators
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• the present disclosure relates generally to controlling generator sets (gensets), especially to controlling gensets to produce power to supply to a utility grid or a load.
• Gensets are used extensively for power generation that starts when the power fails in buildings or sites, such as hospitals, data centers, shopping centers, factories, etc. Gensets are also used to provide power to power grids, used as capacity reserves, or as peak shaving mechanisms. Gensets normally include a prime mover such as an internal combustion (IC) engine that converts fuel into mechanical power to rotate an alternator, or generator. An alternator converts the mechanical energy into useable electrical energy at a line voltage and frequency most suitable for transmission and utilization.
• IC internal combustion
• FIG. 1 shows a typical electricity distribution system during a normal operating condition 100 and during a power outage 114, where the system during condition 100 includes a utility grid 102, also referred to as a power grid, providing electricity to a load 104 which includes for example computing devices 106, home appliances 108, and data centers 110.
• the grid 102 provides sufficient power to the load 104 with a genset 112 disconnected from the grid 102 and acting as a backup power generator.
• the system replaces the grid 102 with the genset 112 to provide power to the load 104 while the utility company addresses the problems which caused the power outage in the utility grid 102.
• the grid 102 is disconnected from the genset 112 to avoid electricity flowing into the utility grid 102 which could interfere with the repair efforts.
• the genset 112 can be connected to and actively providing power to the grid 102 as a capacity reserve, in which the power company operating the grid 102 may purchase electricity produced from the genset 112 at a predetermined price.
• the genset operates in a peak shaving mode to provide some of the electricity needed by the load 104 such that peak electricity demand is reduced for the grid 102.
• a user of the grid 102 is charged a “demand charge” which is based on the peak power consumed by the user, so the peak shaving supplements the power from the grid to suppress this peak, thereby lowering the utility bill for the user.
• FIG. 2 illustrates the components of a typical known genset 112 as shown in FIG.
• the main components of the genset 112 are: a generator 200, a controller 202, a fuel system 204, an intake system 206, a turbocharger system 208, an exhaust system 210, and one or more batteries 212.
• the components of the generator 200 are: an engine 214, a lubrication system 216, a speed control system 218, a coolant system 220, an ignition system 222, a starter motor 224, and an alternator 226.
• the genset 112 is coupled to a set of circuit breakers 228 which connects the genset 112 to the load 104, and the load 104 is coupled to another set of circuit breakers 230 which connects the load 104 to the power grid 102.
• the controller 202 detects that the load 104 is not receiving power from the grid 102 and activates the genset 112. Specifically, a start signal is sent to the genset 112, and the batteries 212 power the starter motor 224 to bring the engine 214 to a cranking speed, which is typically about 150 rpm. Once the engine 214 has reached the cranking speed, fuel is added from the fuel system 204 into the intake system 206, along with air intake as indicated by the arrow depicting airflow. For a synchronous motor, the engine 214 starts and is accelerated to a synchronous speed, i.e.
• FIG. 6 illustrates the engine speed curve 600 of the prior-art genset 112 from when the genset 112 is activated (i.e. at time “0”) to when the genset 112 reaches the synchronous speed at time “A”. [0008] When the engine 214 reaches synchronous speed, the engine speed is stabilized.
• FIG. 7 illustrates a power curve 700 of the power generated by the prior-art genset 112 in relation to time elapsed since the activation of the genset 112. Because gensets can generate power only after reaching synchronous speed, the point where the curve leaves the x-axis indicates the start of power generation by the genset.
• the power generation begins at time “A” on FIG. 7, and plateaus when it reaches 100%, i.e. the target power.
• This process can take several minutes for large spark-ignited engines, while some diesel engine- based gensets can complete this process in approximately 10 seconds.
• even this is too slow for some applications which require immediate backup power in case of a power outage, such as computers and data centers which could experience undesired shutdowns if no power is provided for even 10 seconds, let alone several minutes.
• Various embodiments of the present disclosure relate to methods and apparatuses to reduce a startup time of a genset for providing requested power to a utility grid or a load.
• the genset includes a generator, a turbocharger, and an energy storage device coupled to at least one of the generator and the turbocharger.
• the genset further includes a controller, and the generator includes an engine.
• the genset responds to a genset start signal which, in one example, is caused by a determination that the utility grid is not providing power to the load, and accelerates an engine speed of the generator to reach a synchronous speed by activating the energy storage device to supply power to the at least one of the generator and the turbocharger. Subsequently, the generator supplies power to the utility grid or load.
• the controller detects a condition that the utility grid is not providing power to the load, and then responds to the condition by activating the energy storage device to supply power to the at least one of the generator and the turbocharger and the load to accelerate the engine speed of the generator more rapidly to reach the synchronous speed.
• the energy storage provides power directly to the load.
• the generator further includes an alternator
• the turbocharger includes a shaft and a motor-generator.
• the energy storage device includes at least one of a battery and a supercapacitor which supplies electrical power to at least one of the alternator and the motor-generator.
• the at least one of the battery and the supercapacitor is pre-charged by the utility grid and maintained at a high-power state prior to being activated.
• the genset responds to the genset start signal by disconnecting the utility grid from the load prior to activating the at least one of the battery and the supercapacitor.
• the genset responds to the genset start signal by having the at least one of the battery and the supercapacitor supply power to the load after the utility grid is disconnected from the load.
• the at least one of the battery and the supercapacitor stabilizes the engine speed by: absorbing excess power supplied by the at least one of the alternator and the motor-generator if the engine speed is too high, or providing power to the at least one of the alternator and the motor-generator if the engine speed is too low.
• the at least one of the alternator, the motor-generator, and the utility grid recharges the at least one of the battery and the supercapacitor when the genset is operating at a desired power level.
• the motor-generator increases a turbocharger speed by supplying power to the shaft of the turbocharger.
• the motor-generator stabilizes a turbocharger speed by absorbing power from the shaft. The motor-generator then supplies electrical power by converting the absorbed power into the electrical power. Finally, the at least one of the battery and the supercapacitor absorbs the electrical power supplied by the motor-generator. In another example, at least one of the load and the grid absorbs the power supplied by the motor-generator.
• the turbocharger includes a shaft
• the energy storage device includes at least one flywheel configured to supply power to at least one of the engine and the shaft.
• the at least one flywheel is configured to supply power to the alternator or a coupling that connects the engine to the alternator.
• the at least one flywheel is maintained at a high-power state prior to being activated, and the genset responds to the genset start signal that the utility grid is not providing any power to the load by disconnecting the utility grid from the load prior to activating the at least one flywheel.
• a rate at which the engine speed increases i.e. an engine acceleration, is reduced when the engine speed is within a predetermined threshold from the synchronous speed.
• the energy storage device includes a pair of flywheels: a first flywheel coupled to the generator and a second flywheel coupled to the turbocharger. Both of these flywheels are maintained at a high- power state prior to being activated.
• the controller responds to the detected condition in which the utility grid is not providing power to the load by activating the first flywheel to supply power to the engine and the second flywheel to supply power to the shaft, in order to accelerate the engine speed of the generator to reach the synchronous speed. Also, in this case, the controller reduces the rate at which the engine speed increases when the engine speed is within a predetermined threshold from the synchronous speed by deactivating one or both of the first and second flywheels.
• the generator includes at least one of: a spark ignition engine and a compression ignition engine.
• the power is supplied by the energy storage device while the engine speed increases to approach the synchronous speed.
• the controller reduces a rate at which the engine speed increases when the engine speed is within a predetermined threshold from the synchronous speed by feeding the power back into the flywheels.
• the genset includes a controller which receives a signal from the utility grid requesting the genset to deliver electrical power to the utility grid. In response to receiving the signal, the controller accelerates an engine speed of the generator to reach a synchronous speed using electrical power supplied by the utility grid to at least one of the alternator and the motor-generator. Then, the alternator of the generator supplies the electrical power to the utility grid.
• the genset includes an energy storage device which stabilizes the engine speed by absorbing excess electrical power supplied by the alternator if the engine speed is too high, and/or providing power to the alternator if the engine speed is too low.
• the genset initiates a combustion process of the engine to occur using one or more engine systems based on comparing the engine speed with the synchronous speed.
• the genset supplies power to the utility grid or load based on initiating the one or more engine systems.
• the genset initiates the combustion process based on determining the engine speed is less than the synchronous speed by a pre-determined threshold and greater than the cranking speed.
• the genset initiates the combustion process based on determining the engine speed reaches the synchronous speed.
• the genset provides one or more signals to de-activate the drive motor based on the engine speed reaching the synchronous speed and initiating the combustion process.
• the drive motor is a high torque industrial electrical motor.
• a method and system of reducing a startup time of a genset system for providing requested power to a load includes an engine, one or more batteries, a controller and a drive motor.
• the controller is configured to determine a start condition for the genset system, activate the drive motor to ramp up an engine speed of the engine past a cranking speed and to a synchronous speed, and supply, using the genset system, power to the load based on using the drive motor to ramp the engine speed to the synchronous speed.
• the controller monitors, using an engine speed sensor, the engine speed of the engine, initiates a combustion process of the engine to occur using one or more engine systems based on comparing the engine speed with the synchronous speed, and supplies the power to the load is based on the initiating the combustion process.
• the controller de activates the drive motor based on the engine speed of the engine reaching the synchronous speed and initiating the combustion process.
• the controller initiates the combustion process based on determining the engine speed is less than the synchronous speed by a pre determined threshold and greater than the cranking speed.
• the controller initiates the combustion process based on determining the engine speed reaches the synchronous speed.
• the drive motor is a high torque industrial electrical motor.
• the controller activates the drive motor to ramp up the engine speed to the synchronous speed is based on determining a battery charge of the one or more batteries exceeds a threshold.
• the controller cancels a start request for the genset system and causing display of a prompt indicating the cancellation of the start request based on determining the battery charge of the one or more batteries fails to exceed the threshold.
• the genset system comprises a reserve genset.
• the controller activates the reserve genset to charge the one or more batteries based on determining the battery charge of the one or more batteries fails to exceed the threshold, determines whether the battery charge of the one or more batteries exceeds the threshold subsequent to activating the reserve genset, and supplies the power to the load in response to the battery charge of the one or more batteries exceeding the threshold.
• FIG. 1 is a set of schematic diagrams of a system with a load, grid, and genset in both a normal operation condition and during a power outage;
• FIG. 2 is a schematic diagram of a prior-art genset as shown in FIG. 1;
• FIG. 3 is a schematic diagram of a genset as disclosed herein, which uses an electrical energy storage;
• FIG. 4 is a schematic diagram of a genset as disclosed herein, which uses a pair of flywheels;
• FIG. 5 is a schematic diagram of a turbocharger as used in the genset disclosed in
• FIG. 6 is a graph comparing the startup engine speed curves of the prior-art genset as shown in FIGS. 1 and 2 with two embodiments of the genset as disclosed herein;
• FIG. 7 is a graph comparing the generated power curves of the prior-art genset as shown in FIGS. 1 and 2 with two embodiments of the genset as disclosed herein;
• FIG. 8 is a flow chart illustrating a method of reducing a startup time of a genset for providing requested power to a utility grid or a load as described herein;
• FIG. 9 is a flow chart illustrating a method of reducing a startup time of a genset for providing requested power to a utility grid as described herein;
• FIG. 10 is a schematic diagram of a genset as disclosed herein, which includes a drive motor
• FIG. 11 is a flow chart illustrating a method of reducing a startup time of a genset for providing power to a load as described herein;
• FIG. 12 is another schematic diagram of a genset as disclosed herein, which includes a drive motor.
• FIG. 13 is another flow chart illustrating a method of reducing a startup time of a genset for providing power to a load as described herein.
• FIG. 3 illustrates an example of a genset system 300 as disclosed herein.
• the genset
• the 300 includes a generator 200, a controller 202, a fuel system 204, an intake system 206, a turbocharger system 208, an exhaust system 210, and one or more batteries 212.
• the generator 200 includes an engine 214, a lubrication system 216, a speed control system 218, a coolant system 220, an ignition system 222, a starter motor 224, and an alternator 226.
• the genset 300 further includes an energy storage device 302 electrically coupled to the alternator 226 of the generator 200 and a motor-generator 304 of the turbocharger system 208, as well as to the controller 202 and the circuit breakers 228 and 230.
• the energy storage device 302 can be coupled to either one of the alternator 226 and the motor-generator 304.
• the engine 214 can be any appropriate engine to be used in a generator, such as a spark ignition-based engine and a compression ignition-based engine, among others.
• the fuel system 204 can use any appropriate type of fuel used in spark ignition-based engines, including but not limited to natural gas, propane, gasoline, hydrogen, and other gas phase fuels which includes digester gas, bio gas, producer gas, landfill gas, pipeline gas, etc.
• propane can be any fuel that consists of more than 50% propane, such as liquefied petroleum gas (LPG), for example.
• LPG liquefied petroleum gas
• the types of fuels that compression ignition-based engines can run on include, but are not limited to, diesel, kerosene, jet fuel, heavy fuel oil, etc.
• the energy storage device 302 is a battery or a set of batteries, or a set of supercapacitors, although any other suitable energy storage device medium can be employed as appropriate.
• the functions of the energy storage device 302 as well as the genset 300 are explained in detail below. Note that in FIGS. 3 and 4, the broken lines indicate electrical flow (for example, electrical signal and transfer of electrical energy), while the bold solid lines indicate other types of flow (for example, fluid flow and transfer of mechanical energy) as further explained herein.
• the power grid 102 is electrically connected to the energy storage device 302 such that the energy storage device 302 is maintained at a high charge level, e.g. near 100% of its capacity, by having electrical power supplied from the power grid 102 while the power grid 102 supplies power to the load 104.
• the controller 202 detects the outage using sensors, for example, that measure power within the system, and sends start signals to each of the components of the genset 300 to activate the genset 300. Collectively, these signals are referred to as a genset start signal.
• a start signal is sent to the controller 202 which activates the batteries 212 to provide power to activate the starter motor 224, as well as to each of the lubrication system 216, speed control system 218, coolant system 220, and ignition system 222 of the genset 300.
• a start signal is sent to the energy storage device 302 such that the energy storage device 302 is activated and sends electrical power to the genset 300.
• the energy storage device 302 acts as the uninterruptible power supply (UPS) to the load 104 by supplying electrical power to the load 104 immediately after the outage occurs, independently of the alternator 226.
• the energy storage device 302 is capable of providing as much power as the alternator 226 can deliver at full load, such as 1 megawatt (MW), for instance.
• the energy storage device 302 instantly begins supplying enough power to meet the power demand of the load 104 (i.e., 100% of the generated power) for an amount of time long enough for the engine 214 to reach synchronous speed, after which the alternator 226 takes over and provides the power to the load 104.
• the energy storage device 302 acts as the UPS for the load 104.
• the roles of the batteries 212 and the starter motor 224 are replaced with the energy storage device 302 and the alternator 226, respectively. That is, instead of using the power supplied by the batteries 212 to activate the starter motor 224 for the engine 214 to start building speed, the energy storage device 302 supplies power to the alternator 226 which in turn builds up speed in the engine 214.
• the energy storage device 302 provides electrical power to the alternator 226 of the generator 200 to power the engine 214 as the engine 214 builds speed, and the energy storage device 302 additionally provides power to the motor-generator 304 of the turbocharger system 208 to activate the turbocharger.
• the motor-generator 304 can be any suitable motor-generator used in a turbocharger, for example a permanent magnet alternator (PMA), such that the motor-generator can both supply mechanical power to the shaft of the turbocharger and absorb the mechanical power from the shaft to convert it to electrical power.
• PMA permanent magnet alternator
• the motor-generator 304 is replaced with a motor which supplies power to the shaft of the turbocharger in a unidirectional manner, or is configured such that the motor-generator can be used as just a motor, just a generator, or both depending on the implementation in the genset.
• the energy storage device 302 is coupled to the motor-generator 304 without being coupled to the alternator 226. In this embodiment, the energy storage device 302 provides power solely to the motor-generator 304 to activate the turbocharger, and the energy storage device 302 can also absorb power from the turbocharger, when that is advantageous, for example, to regulate the boost pressure of the engine.
• a turbocharger 208 includes a compressor 500 to deliver air from the atmosphere to the engine 214 through an intake pathway 504, a turbine 502 which rotates in response to the exhaust gas from the engine 214 passing from an exhaust pathway 506, through the turbine 502 to the exhaust system 210, a shaft 406 connecting the compressor 500 to the turbine 502, and the motor-generator 304 which provides mechanical torque to the shaft 406 to rotate.
• the motor-generator 304 receives electrical power from the energy storage device 302, the motor-generator 304 turns the shaft 406 so the turbocharger takes in more air from the atmosphere and delivers it to the engine 214, creating more boost.
• the motor- generator 304 is also capable of absorbing excess mechanical power from the shaft 406 to reduce the speed of the turbocharger 208.
• the RPM of the turbocharger can be modulated using sensors, for example, which detect the speed of the turbocharger so that a warning signal is sent to the controller when the turbocharger speed increases too rapidly, or is too high. Advantages in having such sensors include preventing excessive turbocharger speed which can damage the turbocharger.
• the controller 202 sends signals to the energy storage device 302 to reduce the amount of power supplied to the alternator 226 and the motor-generator 304, thereby decreasing the rate at which the engine speed is increasing (i.e. engine acceleration) to stabilize the engine speed when the synchronous speed is reached.
• the rate at which the engine speed is increasing i.e. engine acceleration
• such decrease in the engine acceleration occurs when the engine speed reaches a certain predetermined threshold.
• the threshold can be 1700 rpm, after which the engine acceleration decreases so that the engine speed reaches 1800 rpm without overshooting the target speed, although any other threshold value less than the synchronous speed can be used as appropriate for this purpose.
• a governor is implemented to determine the speed relative to a threshold, which uses factors such as (1) the difference between the actual speed and the target speed, (2) the rate at which the target speed is approached, or (3) the integral of the difference. Typically, all three of the above factors are combined in a “PID” controller.
• the engine speed curve 602 in FIG. 6 reflects this method of engine speed stabilization.
• the genset 300 begins to generate power after the engine speed reaches the synchronous speed.
• FIG. 7 illustrates the generated power curve 702 of the genset 300 for this embodiment.
• the genset 300 achieves synchronous speed and begins generating power, which is earlier than the prior art genset 112, which achieves the same speed at time “A”, much later than the genset 300.
• the genset 300 also achieves 100% power generation, also referred to herein as a target or desired power level, much earlier than does the prior art genset 112.
• the energy storage device 302 absorbs the excess power generated by the genset 300, essentially acting as a brake, to stabilize the engine speed and to match the phase of the alternator 226 with that of the load 104. Therefore, the controller 202 does not need to reduce the rate at which the engine speed is increasing, allowing the engine speed to reach the synchronous speed earlier than otherwise possible.
• This method of engine speed stabilization is reflected in the engine speed curve 604 in FIG. 6.
• the genset 300 quickly builds power and the motor-generator 304 absorbs the excess mechanical power from the turbocharger 208, converts it into electrical power, and supplies the electrical power to the energy storage device 302, thereby stabilizing the engine speed.
• the engine can be operated at the target speed with the throttle wide open, which improves efficiency of the engine.
• the speed would be controlled by modifying the charge mass flow through the engine, thus controlling the power. This would also prevent the turbocharger from over-speeding, especially if a smaller turbine is used. Moreover, this allows the use of a smaller turbine, which improves the ability of the turbocharger to spool up during transients.
• the circuit breakers 228 close to electrically couple the genset 300 with the load 104 for the genset 300 to provide electrical power to the load 104.
• the energy storage device 302 continues to fill the gap between the power provided by the genset 300 and the power demand from the load 104.
• the energy storage device 302 also continues to supply power to the motor-generator 304 of the turbocharger 208 to help reach target speed or to maintain at the target speed once it is reached, as load is applied to the genset.
• the engine 214 of the genset 300 can operate at a slightly higher power than is demanded so as to recharge the energy storage device 302 with the excess power generated by the genset 300, similar to how the energy storage device 302 is kept at high charge level from the power supplied by the grid 102 during normal operating conditions.
• the energy storage device 302 is charged to a predetermined level, e.g. 80% of its capacity, to allow the energy storage device 302 to act as a support power source for stabilizing engine speed, when necessary.
• the genset 300 experiences load shedding caused by a drop in the load applied to the genset.
• This load shedding event occurs when there is a sudden drop in the load applied to the genset, either because a load is intentionally removed (such as by opening a circuit breaker), or due to a failure in the grid.
• the latter is also referred to as “low voltage ride through” (LVRT).
• LVRT low voltage ride through
• the generator acts as a brake to absorb the excess electrical power generated by the alternator 226.
• the engine speed is then reduced using the motor-generator 304 to absorb mechanical power from the turbocharger 208, which is converted into electrical power to be absorbed by the energy storage device 302.
• the result is a stable engine speed and electrical frequency during the load shedding maneuver.
• the energy storage device 302 is at a higher charger level than before the load shedding event, which allows the energy storage device 302 to prepare for a possible load acceptance event that is anticipated in the future, i.e. when more load is added such that the power demand for the genset 300 increases.
• the energy storage device 302 in this case is kept at a predetermined target level, for example 90% of its capacity, to accommodate for any sudden increase in the amount of power demanded by the load 104.
• the energy storage device 302 supplies electrical power to the alternator 226 or directly to the load 104 to bridge the gap between the power provided by the genset 300 and the power demand from the load 104, while the engine 214 is building speed to achieve the synchronous speed needed to start generating power. Additionally, power is also added to the motor-generator 304 of the turbocharger 208 to allow the turbocharger to spool up quickly.
• Advantages of this approach include the genset having the ability to provide power almost instantaneously to the load while providing excellent transient response, i.e. load shedding and load acceptance, as well as excellent frequency stability.
• the aforementioned genset system can also handle the most demanding “low voltage ride through”, i.e. the capability to stay connected in short periods of lower electric network voltage, as well as other grid compliance requirements.
• FIG. 4 illustrates an example of a genset system 400 which includes a set of flywheels 402 and 404 mechanically coupled to the engine 214 of the generator 200 and a shaft 406 of the turbocharger system 208, respectively.
• the flywheels 402 and 404 are also electrically coupled to the controller 202 to be activated by the controller.
• the flywheels 402 and 404 are part of flywheel energy storages that use electricity to accelerate and decelerate the flywheel composed of rotors suspended by magnetic bearings in a vacuum enclosure, for example, although any other suitable flywheel energy storage device can be employed as appropriate.
• the functions of the flywheels 402 and 404 as well as the genset 400 are explained in detail below.
• the flywheel 402 supplies mechanical power to the engine 214, and the flywheel 404 supplies mechanical power to the shaft 406 (shown in FIG. 4 using solid bold unidirectional arrows).
• the flywheel can also generate electrical power to provide to the system.
• the turbocharger 208 uses the shaft 406 to drive the compressor 500 and the turbine 502 to deliver more air from the atmosphere into the engine 214.
• the engine speed experiences a dramatic increase initially when the genset 400 is activated and fuel is supplied to the engine 214 when the engine speed reaches the cranking speed.
• the controller 202 sends signals to the flywheels 402 and 404 to reduce the amount of power supplied to the turbocharger 208 and the engine 214, thereby decreasing the rate at which the engine speed is increasing to stabilize the engine speed when the synchronous speed is reached.
• the engine speed curve 602 in FIG. 6 illustrates this method of engine speed stabilization.
• the controller 202 prevents the engine speed from exceeding the synchronous speed.
• the genset system includes an additional compressor and electric motor.
• the additional compressor is connected in series with or in parallel to the turbocharger 208 such that the boost is created using the additional compressor until the turbocharger is up to speed.
• the electric motor is coupled to the additional compressor.
• the electric motor is coupled to the turbocharger 208 and a second separate electric motor is coupled to the compressor to assist with the boost.
• the electric motors can be motor-generators, as appropriate.
• the flywheels 402 and 404 are used in combination with a separate UPS to provide gapless power to the load 104.
• the UPS can be a set of supercapacitors which provide electrical power to the alternator 226 and the motor-generator 304, while the flywheels provide mechanical power to the engine 214 and the shaft 406.
• the UPS provides electrical power directly to the load, allowing the load to continue running without interruption. Advantages of this configuration include dramatically reducing the genset startup time, the time it takes for the engine to reach synchronous speed, and the time it takes for the load to receive 100% of its power demand.
• the energy storage device 302 includes supercapacitors which are used to supply the reactive power element of the load 104 during startup. Advantages in this method includes reducing the size and capacity of the system by approximately 20%. For example, starting up a motor, or providing the power to start up a transformer from a black start, requires a sudden in-rush (typically taking between 2 to 5 seconds) of reactive power, which require the genset 300 to be oversized. Using the supercapacitors to power the reactive elements of the load not only enables downsizing of the genset but also enables operation with a power factor close to 1.0, which means that almost all the supplied power is consumed by the load, therefore improving the efficiency of the genset.
• Advantages in having an energy storage device or flywheels to assist in the startup of the genset include reducing the time it takes for the genset to reach power generation of 100% to meet the power demand of the load, allowing for almost gapless, if not actually gapless, power to be supplied to the load during power outages, improving the efficiency of the engine, and reducing the size and capacity necessary for the system, without compromising on the performance.
• the genset as described herein is used as a capacity reserve for the utility grid or power grid 102. This may happen, for example, when the utility company has determined that the company is, or soon will be, unable to provide all the power that is requested from the grid.
• the controller 202 receives a signal indicating that the grid 102 needs the genset to generate power to supplement or support the grid 102 in meeting the demand from all the loads.
• the signal acts as the trigger for the controller 202 to activate the genset.
• the grid 102 then provides electrical power to the alternator 226 of the generator 200 and the motor-generator 304 of the turbocharger 208 to start the engine 214 to reach the synchronous speed.
• the motor-generator 304 can be used as a motor, a generator, or both.
• the genset in this case can be either the genset 300 or the genset 400.
• the energy storage device 302 and the flywheels 402 and 404 can remain deactivated, or omitted entirely from the system, because the power needed to speed up the engine 214 and the turbocharger 208 comes from the grid 102.
• the energy storage device 302 can be used as a brake to stabilize the engine speed, as explained previously herein, after the engine 214 achieves the synchronous speed and the alternator 226 starts generating electrical power. The generated power is then supplied to the grid 102 so that the grid 102 can meet the demand for the loads which receives power from the grid.
• the motor-generator 304 can also be used as the brake as well to stabilize the turbocharger RPM in one example.
• FIGs. 8 and 9 show a flow chart illustrating the steps in operating the genset as described herein.
• FIG. 8 pertains to a method of reducing a startup time of a genset for providing requested power to a utility grid or a load.
• the controller of the genset detects a condition in which the utility grid is not providing power to the load.
• the controller accelerates an engine speed of the generator to reach a synchronous speed by activating the energy storage to supply power to the at least one of the generator and the turbocharger.
• the generator supplies power to the utility grid or load.
• FIG. 9 pertains to a method of reducing a startup time of a genset for providing requested power to a utility grid.
• step 900 the controller receives a signal from the utility grid requesting the genset to deliver electrical power to the utility grid. Then, in step 902, the controller accelerates an engine speed of the generator to reach a synchronous speed using electrical power supplied by the utility grid to at least one of the alternator and the motor-generator. And finally, in step 904, the alternator supplies the electrical power to the utility grid.
• the signal comes from a remote controller handled by the owner of the genset such that the genset is used in a peak shaving mode to reduce the demand charge and run the genset only when the load is high enough to trigger the demand charge.
• FIG. 10 illustrates another example of a genset system 1000.
• the genset system
• the genset system 1000 includes similar components to the exemplary genset systems in FIGs. 2, 3, and 4. Furthermore, the genset system 1000 includes a drive motor 1002 that is operatively coupled to the batteries 212.
• the drive motor 1002 is the same as the starter motor 224.
• the starter motor 224 / the drive motor 1002 is an electric motor, a pneumatic motor, a hydraulic motor, and/or an internal combustion engine.
• the batteries 212 provide power to the drive motor 1002.
• the drive motor 1002 ramps up the engine 214 to a cranking speed (e.g., 150 rpm).
• the drive motor 1002 continues to ramp up the engine past the cranking speed and to the synchronous speed (e.g., 1500 rpm).
• the drive motor 1002 is a high torque industrial electrical motor.
• the high torque industrial electrical motor may be a 100 horsepower (HP) or greater motor.
• some starter motors may be smaller and/or less powerful since the starter motor only needs to ramp up the engine 214 to a cranking speed.
• a more powerful electrical motor such as a high torque industrial electrical motor, may be used to ramp up the engine 214 past the cranking speed and to the synchronous speed.
• the drive motor 1002 may be two or more motors.
• the drive motor 1002 may include a starter motor that ramps the engine 214 up to the crank speed and a second motor (e.g., a high torque industrial electrical motor) that ramps the engine 214 up to the synchronous speed.
• the drive motor 1002 may ramp up the engine 214 by being input directly to the crankshaft via a direct 1 : 1 coupling (e.g., the front of the engine 214), may be input to the crankshaft via a belt drive (e.g., crankshaft pulley), may be input to the crankshaft via a gear or chain drive (e.g., the front gear train), may be input directly to the crankshaft via a flywheel (e.g., flywheel gear).
• the final drive ratio involving pulleys and/or gears may be designed to coordinate with the engine/generator synchronization speed.
• the genset system 1000 also includes one or more additional electrical connections (e.g., dotted lines) between the power grid 102 to the batteries 212 and/or between the alternator 226 to the batteries 212.
• the additional electrical connections assist with charging the batteries 212 used to start / activate the drive motor 1002.
• the drive motor 1002 may use more power to ramp the engine 214 up to the synchronous speed.
• the additional electrical connections may assist in charging the batteries 212 up to a higher charge to assist with the increased power usage to ramp the engine 214 up to the synchronous speed.
• FIG. 11 shows a method 1100 illustrating the steps in operating the genset system
• the controller 202 may use method 1100 to ramp the engine 214 past the cranking speed and to the synchronous speed using the drive motor 1002.
• the controller 202 determines an engine and/or generator start condition. For example, as mentioned previously, the power grid 102 may cease providing power to the load 104. The controller 202 may detect this situation and the method 1100 may move to step 1104.
• the engine and/or generator start condition may be based on a user input. For instance, the controller 202 receives user input indicating to start the genset system 1000. Based on the user input, the controller 202 determines the start condition and the method 110 moves to step 1104.
• the controller 202 determines whether the battery charge (e.g., charge of the batteries 212) exceeds a threshold.
• the threshold may be user-defined (e.g., the controller 202 receives user input indicating the threshold) or pre-determined. If the controller 202 determines the battery charge exceeds the threshold, the method 1100 moves to step 1110. Otherwise, the method 1100 moves to step 1106.
• step 1106 the controller 202 cancels the start request for the genset system 1000
• the controller 202 causes display of a prompt indicating a system status (e.g., the battery charge fails to exceed the threshold). In other words, if the charge of the batteries 212 fails to exceed the threshold, the controller 202 cancels the start request and displays a prompt to the user indicating that the genset system 1000 has failed to start due to the low battery charge. [0065] If the charge of the batteries 212 exceeds the threshold, the method 1100 moves to step 1110. At step 1110, the controller 202 activates the drive motor 1002. For example, the controller 202 provides one or more signals to the batteries 212 to begin providing power to activate the drive motor 1002. The drive motor 1002 is used to rotate (e.g., crank) the engine 214 to a speed, such as the synchronous speed.
• the controller 202 based on comparing the engine speed of the engine 214 with the synchronous speed, the controller 202 initiates a combustion process using one or more engine systems (e.g., engine fueling systems and/or ignition systems).
• a sensor such as an engine speed sensor, may provide feedback to the controller 202.
• the controller 202 monitors the feedback from the engine speed sensor to determine the engine speed (e.g., rotations per minute).
• the controller 202 compares the engine speed from the engine speed sensor with a threshold (e.g., a synchronous speed threshold). Based on the engine speed reaching the synchronous speed threshold, the controller 202 initiates engine systems such as the engine fueling systems and/or the ignition systems.
• the drive motor 1002 continues ramping up the engine speed past the cranking speed and to the synchronous speed.
• the controller 202 initiates the engine systems, which will cause combustion.
• the controller 202 activates the fueling systems 204 to deliver fuel to the intake system 206 and/or control the intake system 206 to receive airflow.
• the engine 214 may use the fuel and airflow to begin the combustion process once the engine speed reaches the synchronous speed. Then, the method moves to step 1114.
• the controller 202 instead of activating the engine speeds to cause combustion to rotate the engine 214 after the engine 214 reaches the cranking speed, the controller 202 initiates the engine systems to cause combustion in response to the engine 214 reaching the synchronous speed.
• the operational time between the engine 214 reaching the synchronous speed from the cranking speed may be reduced by using the drive 1002 to ramp up the engine 214 up to the synchronous speed.
• the controller 202 initiates the combustion process based on determining the engine speed of the engine 214 is less than the synchronous speed and greater than the cranking speed. For example, the controller 202 compares the engine speed from the engine 214 with an engine speed threshold.
• the engine speed threshold may be greater than the cranking speed (e.g., 200 RPM), but less than the synchronous speed (e.g., 1800 RPM). For instance, the engine speed threshold may be 1500 RPM.
• the controller 202 initiates the combustion process using the engine systems. In other words, the controller 202 initiates the combustion process after the cranking speed has been reached by the engine 214, but prior to reaching the synchronous speed.
• the controller 202 may receive user input adjusting the engine speed threshold.
• the controller 202 transitions the load management to the engine 214 and/or de-activates the drive motor 1002. For example, after the engine 214 reaches the synchronous speed and/or initiates the combustion process, the controller 202 de-activates the drive motor 1002 (e.g., by providing one or more signals to the batteries 212 to cease providing power to the drive motor 1002). Additionally, and/or alternatively, since the engine 214 is at the synchronous speed, the controller 202 transitions the load management to the engine 214 to cause the engine 214 to use the combustion process to provide power to the load 104.
• transitioning the load management to the engine 214 may be gradual. For example, prior to reaching the synchronous speed (e.g., after the engine speed reaches a threshold such as the engine speed threshold), the controller 202 initiates the combustion process using one or more engine systems (e.g., begin providing fuel to the engine 214 to produce power). The controller 202 continuously reduces (e.g., ramps down) the power provided by the drive motor 1002 and continuously increases (e.g., ramps up) the amount of fuel to the engine 214. After a pre-determined period of time, the controller 202 may transition the engine 214 to use the combustion process for power and de-activate the drive motor 1002.
• the controller 202 may transition the engine 214 to use the combustion process for power and de-activate the drive motor 1002.
• the controller 202 stabilizes the engine speed and load at the synchronous speed. For example, the controller 202 stabilizes and ensures that the output shaft of the engine 214 and the input shaft of the load 104 are at the synchronous speed and/or do not fluctuate significantly from the synchronous speed. In other words, after de-activating the drive motor 1002, the engine speed may fluctuate for a period of time at the synchronous speed. The controller 202 may stabilize the engine speed and load at the synchronous speed prior to supplying power to the load using the engine 214.
• the controller 202 synchronizes and initiates power generation to the load 104 using the engine 214 (e.g., supplying power to the load 104). Additionally, and/or alternatively, after initiating power generation using the engine 214, the controller 202 may use the engine 214 (e.g., the alternator 226) to recharge the batteries 212. For example, the generator 200 and engine 214 may be running at different speeds. The controller 202 may use the engine speed sensor and/or one or more other sensors to synchronize the speeds of the generator 200 and the engine 214. After synchronizing the speeds, the controller 202 initiates power generation to the load 104 using the engine 214.
• the engine 214 e.g., the alternator 2266
• the energy storage device 302 is optional.
• the energy storage 302 which is described above, may replace the batteries 212.
• the controller 202 uses (e.g., provides one or more control signals to) the energy storage device 302 to provide power to the drive motor 1002 to ramp up the engine 214 to the synchronous speed.
• the controller 202 uses the energy storage 302, the batteries 212, the motor-generator 304, the turbocharger system 208, and/or the drive motor 1002 to ramp up the engine 214 to the synchronous speed.
• the controller 202 uses the method 1100 (e.g., the drive motor 1002) to ramp up the engine 214 to the synchronous speed.
• the controller 202 uses methods 800 and/or 900 described above to accelerate the engine speed to reach the synchronous speed by using the energy storage device 302 to provide electrical power to the alternator 226 of the generator 200 to power the engine 214 as the engine 214 builds speed. Additionally, and/or alternatively, the controller 202 uses the energy storage device 302 to provide power to the motor-generator 304 of the turbocharger system 208 to activate the turbocharger. [0075] In some variations and referring to the genset system 400, the controller 202 uses the flywheels 402 / 404, the batteries 212, the shaft 406 connecting the compressor 500 to the turbine 502, the turbocharger system 208, and/or the drive motor 1002 to ramp up the engine 214 to the synchronous speed.
• the controller 202 uses the method 1100 (e.g., the drive motor 1002) to ramp up the engine 214 to the synchronous speed. Furthermore, the controller 202 uses methods 800 and/or 900 described above to accelerate the engine speed to reach the synchronous speed by using the flywheels 402/404 to power the engine 214 as the engine 214 builds speed.
• the method 1100 e.g., the drive motor 1002
• the controller 202 uses methods 800 and/or 900 described above to accelerate the engine speed to reach the synchronous speed by using the flywheels 402/404 to power the engine 214 as the engine 214 builds speed.
• FIG. 12 illustrates another example of a genset system 1200.
• the genset system
• the genset system 1200 includes similar components to the exemplary genset systems in FIGs. 2, 3, 4, and/or 10. Furthermore, the genset system 1200 includes a reserve genset 1202. The reserve genset 1202 may be a smaller genset and may be operatively coupled to the batteries 212. The reserve genset 1202 may also receive fuel from the fueling system 204 and use a combustion process to provide power to the batteries 212. The controller 202 then uses the batteries 212 to provide power to the drive motor 1002 to ramp up the speed of the engine 214 to the synchronous speed as described above.
• FIG. 13 shows a method 1300 illustrating the steps in operating the genset system
• the controller 202 may use method 1300 to ramp the engine 214 past the cranking speed and to the synchronous speed using the drive motor 1002.
• Method 1300 has many similar steps to method 1100. However, if the controller 202 determines the battery charge fails to exceed the threshold at step 1304, the method 1300 moves to step 1306. At step 1306, the controller 202 activates the reserve genset 1202 and charges the batteries 212. In other words, the controller 202 provides one or more signals to initiate the combustion process for the reserve genset 1202 to recharge the batteries 212. Then, the method 1300 moves back to step 1304 and the controller 202 determines whether the charge of the batteries 212 exceeds the threshold.
• the reserve genset 1202 may be a manual start genset 1202.
• the user may manually start the reserve genset 1202.
• the controller 202 may provide a prompt on a display. The prompt may indicate for the user to manually start the reserve genset 1202 to recharge the batteries 212 based on the charge of the batteries 212 failing to exceed the threshold.
• the power grid 102, the circuit breakers 230, and/or the energy storage 302 are optional. When present, these components / systems may operate as described above to reduce the time required to ramp up the engine 214 to the synchronous speed.
• the reserve genset 1202 may charge the batteries 212 such that there is enough charge for the drive motor 1002 to ramp the engine 214 up to the synchronous speed.
• the genset system 1200 may be in a remote location that might not be connected to the power grid. As such, after determining an engine and/or generator start request, the controller 202 may use the reserve genset 1202 to charge the batteries 212 to a sufficient charge to power the drive motor 1002 to ramp up the engine 214 to the synchronous speed.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Supercharger (AREA)

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• 2020
  • 2020-08-21 CN CN202080070041.1A patent/CN114556772A/zh active Pending
  • 2020-08-21 EP EP20874887.1A patent/EP4042560A4/de active Pending
  • 2020-08-21 WO PCT/US2020/047417 patent/WO2021071596A1/en unknown

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