WO2023019418A1 - 一种备用电源及其运行方法 - Google Patents

一种备用电源及其运行方法 Download PDF

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Publication number
WO2023019418A1
WO2023019418A1 PCT/CN2021/112916 CN2021112916W WO2023019418A1 WO 2023019418 A1 WO2023019418 A1 WO 2023019418A1 CN 2021112916 W CN2021112916 W CN 2021112916W WO 2023019418 A1 WO2023019418 A1 WO 2023019418A1
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WO
WIPO (PCT)
Prior art keywords
power
power supply
sub
switch
converter
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PCT/CN2021/112916
Other languages
English (en)
French (fr)
Inventor
张忻庾
温进
徐其惠
胡子晨
顾伟
Original Assignee
远景能源有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 远景能源有限公司 filed Critical 远景能源有限公司
Priority to CN202180002378.3A priority Critical patent/CN114223105B/zh
Priority to AU2021460338A priority patent/AU2021460338A1/en
Priority to EP21953671.1A priority patent/EP4391295A1/en
Priority to PCT/CN2021/112916 priority patent/WO2023019418A1/zh
Publication of WO2023019418A1 publication Critical patent/WO2023019418A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
    • H02J3/0073—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources for providing alternative feeding paths between load and source when the main path fails, e.g. transformers, busbars
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects
    • 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
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems

Definitions

  • the present invention generally relates to the field of wind power generators, and more specifically relates to a backup power supply and an operating method thereof. Furthermore, the invention also relates to a wind generator with such a backup power source.
  • a wind turbine (or fan for short) has many important components that need to be powered, such as pitch bearings, yaw bearings, and control circuits.
  • the stable power supply of these important components directly determines the normal operation and operation safety of the fan.
  • these components are powered by the AC grid. But in the event of a failure of the AC grid, these components must be powered by a backup source.
  • the current backup power supply is difficult to adapt to the large power changes of the electric load. Therefore, there is a need for a backup power supply that has high reliability and can adapt to large load power changes such as wind turbines, and power consumption requirements under extreme conditions, especially when the grid is powered off.
  • the task of the present invention is to provide a backup power supply that integrates multiple power sources and its operation method.
  • the backup power supply and/or the operation method can provide high reliability and can adapt to the power requirements of wind turbines.
  • a backup power supply comprising:
  • a first sub-power supply configured to provide AC power, wherein the first sub-power supply is connected to an input terminal of an AC/DC converter;
  • an AC/DC converter configured to convert AC power to DC power, wherein an output of the AC/DC converter is connected to an output of a backup power supply;
  • a second sub-power supply configured to provide DC power, wherein the second sub-power supply is connected to the output terminal of the standby power supply.
  • alternating current power covers alternating current, alternating voltage and alternating power
  • direct current power covers direct current, direct voltage and direct power
  • AC/DC converter covers a variety of devices that convert AC power to DC power, such as diodes, half-wave rectifiers, full-wave rectifiers, thyristors, fully controlled bridges, and more.
  • sub-power supply refers to various electrical equipment that can provide AC or DC power, such as batteries, generators, etc., wherein the sub-power supply especially refers to a power supply outside the grid, that is, under extreme conditions, especially when the grid is powered off. put into use the power supply.
  • generators may cover various types of generators, especially fuel generators, including, for example: diesel generators, hydrogen generators, ethanol generators, fossil fuel generators and so on.
  • the backup power supply also includes:
  • a first switch wherein the first sub-power supply is connected to the input terminal of the AC/DC converter through the first switch.
  • the backup power supply also includes:
  • a DC/DC converter configured to convert DC power into DC power with different parameters, wherein the DC/DC converter is connected between the second sub-power supply and the output terminal of the backup power supply, and the DC/DC The output terminal of the converter is connected to the output terminal of the standby power supply through the second switch.
  • the DC/DC converter is not necessary.
  • the DC/DC converter is not required.
  • the output electric energy of the second sub-power supply cannot directly supply power to the load but needs to be converted (for example, the conversion of current and voltage)
  • a DC/DC converter is required.
  • the first sub-power supply includes one or more of the following:
  • the second sub-power supply includes one or more of the following:
  • the DC/DC converter is a bidirectional DC/DC converter, and wherein the backup power supply also includes:
  • a third switch wherein the AC grid is connected to the input terminal of the AC/DC converter through the third switch.
  • bidirectional DC/DC converter means that DC power can be input from the input terminal or output terminal of the bidirectional DC/DC converter, and converted DC power can be output at the output terminal or input terminal.
  • the first switch and/or the second switch and/or the third switch comprise one of the following: a power switch, a circuit breaker, a contactor, and a relay.
  • the backup power supply also includes:
  • An inverter configured to convert DC power into AC power, wherein the input of the inverter is connected to the output of the backup power supply, and the output of the inverter is connected to a load.
  • the backup power supply also includes a controller, and the controller is configured to perform the following actions:
  • the first switch and/or the second switch is closed to access the first sub-power supply and/or the second sub-power supply, wherein after closing the second In the case of a switch, the DC/DC converter works forward to discharge the second sub-supply, where:
  • the first switch and the second switch are closed to access the first sub-power supply and the second sub-power supply.
  • the average power and peak power requirements of the load can be met.
  • AC backup power sources such as diesel generators have high energy density and are therefore suitable for providing average power to the load
  • DC backup power sources such as fuel cells It has high response speed, parallel expansion capability and high power density, so it is suitable for providing peak power for loads. Therefore, when the load power requirement is low, that is, the power threshold is not exceeded, the AC backup power supply can be used to provide electric energy for the load to provide average power, and when the load power requirement is high, that is, the power threshold is exceeded, the DC backup power supply can be used To provide electrical energy to the load to provide peak power.
  • the power threshold can be determined according to a specific calculation method, so as to better meet the power demand of the load. It should be pointed out that the present invention is not only applicable to the field of wind power generators, but also applicable to other fields with electric loads, such as the field of photovoltaics (such as using the backup power of the present invention to supply power to components such as photovoltaic control circuits), the field of meteorological equipment, Lighting facilities and so on.
  • controller is further configured to perform the following actions:
  • the second switch When it is detected that the voltage of the AC power grid connected through the third switch is higher than the voltage threshold and the power of the second sub-power supply is lower than the power threshold, the second switch is closed, wherein the DC/DC converter works in reverse, so that the power from the AC grid Charge the second sub-power supply.
  • the second backup power supply can be charged when the second backup power supply is not in use, thereby realizing the availability of the second backup power supply at any time.
  • the first switch and the second switch are closed to access the first sub-power supply and the second sub-power supply, so that the first sub-power supply co-powered with the second sub-power supply, wherein the DC/DC converter operates forwardly to discharge the second sub-power supply;
  • the second switch When the grid voltage is higher than the voltage threshold and the electric quantity of the second sub-power supply is lower than the electric quantity threshold, the second switch is closed, wherein the DC/DC converter works in reverse so as to charge the second sub-power supply from the AC grid.
  • the method also includes the following steps:
  • P threshold P average * a + P peak * (1-a), where 0 ⁇ a ⁇ 1, where P average is the average power required by the power load, which can be counted according to minute-level load data; P peak is the power load The peak power can be counted according to the second-level load data; a is the proportional coefficient, through which the power threshold can be adjusted according to the actual system operating conditions.
  • the average value of P is 34kW
  • the peak value of P is 73kW
  • a is 0.6
  • the threshold value of P can be set to 57kW.
  • the inventor found through research that by adjusting a, the time point of transition from average power to peak power can be adjusted, that is, when the load power reaches a certain point between the average power and peak power, the power of the backup power supply is adjusted to the peak power or above. The smaller a is, the earlier the time point is, and vice versa. Research proves that when a takes 0.6 to 0.8, better power transition can be achieved.
  • the ratio between the power of the generator (such as a diesel generator) and the average power of the load of the power supply is greater than or equal to 1:1, and the ratio between the power of the generator and the peak power of the load of the power supply
  • the ratio of is less than or equal to 1:2 (that is, less than or equal to 0.5), in this case, the power of the generator (first sub-power supply) is less than or equal to the power of the battery pack (second sub-power supply).
  • the invention also relates to a wind generator with a backup power supply according to the invention, wherein the load connected at the output of the backup power supply comprises one or more of the following: yaw bearings, pitch bearings , and the control circuit.
  • the load may be a photovoltaic control circuit, or an active device in the photovoltaic device and the like.
  • the present invention has at least the following beneficial effects:
  • the inventors have found through research that, in the power consumption scene such as a fan, the power of the power load such as the pitch bearing and the yaw bearing may be between the average power and the like due to factors such as wind force.
  • AC backup power sources such as diesel generators have higher energy density, so they are suitable for providing average power for loads
  • DC backup power sources such as fuel cells and supercapacitors
  • the power supply has high response speed (connection means power supply), parallel expansion capacity (infinitely parallel battery expansion) and high power density, so it is suitable for providing peak power for the load, so the inventor found that if the backup power supply has mutual parallel connection
  • the AC backup power supply and the DC backup power supply can better take into account the average power and peak power of the load, thereby better meeting the power demand of the load.
  • the inventors also found that the switching from AC power supply to DC power supply or AC power supply + DC power supply can be achieved by reasonably setting the power threshold, so that the output power transient can be realized more quickly.
  • the inventor rationally arranges the circuit structure so that the second backup power can be charged from the AC grid when the second backup power is not in use, thereby realizing the availability of the second backup power at any time.
  • the present inventor has found surprisingly that, through the circuit arrangement of the present invention, the load is connected to the AC power grid through a converter (AC/DC converter, inverter), so that the load and the previous stage
  • the grid transformers are isolated from each other, so that the power consumption unit, that is, the load, is connected to the DC bus after being transformed by the converter, thereby improving the system efficiency of the backup power supply and reducing operation and maintenance costs and hardware investment.
  • Fig. 1 shows the schematic diagram of the applied wind generator of the present invention
  • Figure 2 shows a circuit diagram of a backup power supply that fuses multiple power supplies according to the present invention.
  • FIG. 3 shows the sequence of the method for operating the backup power supply according to the invention.
  • the quantifiers "a” and “an” do not exclude the scene of multiple elements.
  • connection may refer to the direct connection of the two, or the indirect connection of the two through intermediate elements.
  • the present invention is not only applicable to the field of wind power generators, but also suitable for other fields with electric loads, such as the field of photovoltaics (such as using the backup power of the present invention to supply power to components such as photovoltaic control circuits), meteorological Equipment areas, lighting facilities, etc.
  • the inventor found through long-term research in the field of wind power generators that in the power consumption scene of the wind turbine, the power loads such as pitch bearings and yaw bearings are affected by factors such as wind force, adjustment speed, and mechanical resistance. Its power may have an instantaneous or short-term jump on the basis of the average power, that is, peak power may appear. Therefore, under extreme conditions, especially when the grid is powered off, the backup power supply also needs to take into account the average power and peak power of the load.
  • AC backup power sources such as diesel generators have high energy density, so they are suitable for providing average power for loads
  • DC backup power sources such as fuel cells have high response speed (communication is power supply), parallel expansion capacity (infinitely parallel battery expansion) and high power density, so they are suitable for providing peak power for loads
  • the inventors found that , if the backup power supply has an AC backup power supply and a DC backup power supply connected in parallel with each other, the average power and peak power of the electric load can be well taken into account, thereby better meeting the power consumption needs of the load.
  • the inventors also found that the switching from AC power supply to DC power supply or AC power supply + DC power supply can be achieved by reasonably setting the power threshold, so that the output power transient can be realized more quickly.
  • the inventor rationally arranges the circuit structure so that the second backup power can be charged from the AC grid when the second backup power is not in use, thereby realizing the availability of the second backup power at any time.
  • the present inventor has found surprisingly that, through the circuit arrangement of the present invention, the load is connected to the AC power grid through a converter (AC/DC converter, inverter), so that the load and the previous stage
  • the grid transformers are isolated from each other, so that the power consumption unit, that is, the load, is connected to the DC bus after being transformed by the converter, thereby improving the system efficiency of the backup power supply and reducing operation and maintenance costs and hardware investment.
  • FIG. 1 shows a schematic diagram of a wind power generator 100 to which the present invention is applied.
  • the wind power generator 100 shown in FIG. 1 comprises a tower 101 , a nacelle 102 rotatably connected to the tower 101 and supporting a hub 103 .
  • Two or more blades 104 are arranged on the hub 103, wherein the blades 104 drive the rotor (not shown) arranged in the hub 108 to rotate around the axis (not shown) under the wind force, wherein the rotor of the generator is opposite to The rotation of the stator generates electricity.
  • the wind turbine 100 may include various loads that consume electric energy, such as pitch bearings, yaw bearings, and control circuits. Under normal circumstances, the loads of the wind power generator 100 are powered by the AC grid, but in the event of a fault or power outage in the AC grid, backup power must be used to supply power to these loads, otherwise, these loads cannot operate.
  • FIG. 2 shows a circuit diagram of a backup power supply 200 merging multiple power supplies according to the present invention.
  • the backup power supply 200 includes the following components, some of which are optional:
  • a first sub-power source 201 configured to provide AC power, including AC current, AC voltage, and AC power, for example.
  • the first sub-power supply is connected to the input terminal of the AC/DC converter 206 through the first switch 203 .
  • the first switch 201 may be, for example, a power switch, a circuit breaker, a contactor or a relay.
  • the first sub-power source 201 is preferably a diesel generator, such as an 80kW diesel generator. Due to its high energy density, fuel generators can provide average power for a long time.
  • only a single first sub-power supply 201 is shown. In other embodiments, multiple first sub-power supplies 201 may also be provided, and they are connected in parallel with each other.
  • AC/DC converter 206 configured to convert AC power into DC power, wherein the output of the AC/DC converter is connected to the output OUT of the backup power supply.
  • the AC/DC converter may include various devices for converting AC power into DC power, such as diodes, half-wave rectifiers, full-wave rectifiers, thyristors, fully-controlled bridges, and the like.
  • a second sub-power source 202 configured to provide DC power, including DC current, DC voltage, and DC power, for example.
  • the second sub-power supply 202 is connected to the input terminal of the DC-to-DC converter 213 or directly connected to the output terminal OUT of the standby power supply 200 without the DC/DC converter 213 .
  • two second sub-power supplies 202 are shown.
  • a single or more second sub-power sources 202 may also be provided, which are connected in series with corresponding DC/DC converters 213 and then connected in parallel with each other.
  • the second sub-power source 202 is a plurality of batteries (such as fuel cells or other batteries) connected in series, which can provide multiple battery voltages.
  • the first sub-power source 202 can also be a plurality of batteries (such as fuel cells or other batteries) connected in parallel to provide multiple battery currents.
  • the number of batteries connected in parallel or in series can be arbitrary, for example, can be determined according to the values of average power and peak power.
  • An optional DC/DC converter 213, which is configured to convert the DC power input from the second sub-power source 202 into DC power with different parameters, wherein the output terminal of the DC/DC converter passes through the second switch 204 is connected to the output of the backup power supply.
  • the second switch 204 may be, for example, a power switch, a circuit breaker, a contactor or a relay.
  • the DC/DC converter 213 converts the input DC power into DC power with different current or voltage values, and the magnitude of the current and voltage can be determined according to the required power or rated current or rated voltage of the load. In this embodiment, two DC/DC converters 213 are shown.
  • a single or more DC/DC converters 213 may also be provided, which are connected in series with the corresponding second sub-power sources 202 and then connected in parallel with each other.
  • the DC/DC converter 213 is especially a bidirectional DC/DC converter, wherein the bidirectional DC/DC converter refers to the direct current power (forward work) from the input terminal of the bidirectional DC/DC converter, and the output terminal Output converted DC power, or input DC power from the output terminal of the bidirectional DC/DC converter, and output converted DC power at the input terminal (reverse operation).
  • the third switch 205 may be, for example, a power switch, a circuit breaker, a contactor or a relay. Through corresponding control, the AC grid 208 can not only supply power to the load, but also charge the first and/or the second sub-power supply.
  • An optional inverter 207 configured to convert DC electrical energy to AC electrical energy.
  • the input terminal of the inverter 207 is connected to the output terminal OUT of the backup power supply, and the output terminal of the inverter is connected to the load.
  • a capacitor 210 can be connected between the two input terminals of the inverter 207 .
  • the capacitor 210 can, for example, suppress high-frequency clutter/harmonic waves in electric energy input from the grid or sub-power supply, and can also absorb reactive current of inductive loads in the circuit.
  • a pre-charging circuit 211 comprising a switch and a fuse connected in parallel with the switch.
  • the function of the pre-charging circuit 211 is to ensure that the pre-charging current does not exceed the threshold value during pre-charging (the switch is turned off), so as to avoid damage to components in the circuit.
  • Multiple inverters 207 can be provided to supply power to different AC loads 209 respectively.
  • the AC load 209 is, for example, a yaw motor and a control circuit.
  • the first switch 203 and/or the second switch 204 are closed to connect the first sub-power supply 203 and/or The second sub-power supply 204, wherein when the second switch 204 is closed, the DC/DC converter 213 works forward, so that the second sub-power supply 202 is discharged, wherein:
  • the expected output power of the standby power supply 200 (for example, the rated power of the load 209) is less than or equal to the power threshold, close the first switch 203 and open the second switch 204 to access the first sub-power supply 201; and
  • the first switch 203 and the second switch 204 are closed to access the first sub-power supply 201 and the second sub-power supply 202;
  • the second switch 204 When it is detected that the voltage of the AC grid 208 connected through the third switch 205 is higher than the voltage threshold and the electric quantity of the second sub-power supply 202 is lower than the electric quantity threshold, the second switch 204 is closed, wherein the DC/DC converter 213 works in reverse , so that the second sub-power source 202 is charged from the AC grid 208 .
  • the working flow of the standby power supply 200 according to the present invention is described below.
  • the third switch 205 When the AC grid 208 supplies power normally, the third switch 205 is closed, so that the AC power of the AC grid 208 is rectified by the rectifier 206 and inverted by the inverter 207 to supply power to the AC load 209 . Therefore, the AC load 209 and the AC grid 208 can be isolated from each other through the converter, thereby eliminating harmful electrical signals such as higher harmonics and clutter generated by the upper transformer, and avoiding damage to the AC load 209 .
  • the first switch 203 and/or the second switch 204 are closed, and the DC/DC The converter 213 works in reverse mode, so that the first sub-power source 202 is charged from the AC grid 208 .
  • the first switch 203 and/or the second switch 204 can be turned off. This reverse charging allows the sub-power supply to be charged at any time and be in a usable state at any time.
  • the operating method of the standby power supply of the present invention will be described below by taking an offshore wind power generator as an example.
  • Anti-typhoon yaw backup power application for offshore wind power generators
  • the offshore wind power generator When the offshore wind power generator encounters a typhoon power grid failure, it can switch to the backup power supply of the present invention to drive the yaw system to operate normally, reduce the load of the whole machine, and greatly improve the reliability of the offshore wind turbine.
  • the startup and shutdown status of the backup power supply is as follows:
  • Power grid power-off switching backup power supply 400Vac power failure, when Udc drops to the starting discharge threshold of the bidirectional DCDC converter, the battery and bidirectional DCDC converter supply power to the bus; the grid circuit breaker is disconnected, the backup AC power circuit breaker is closed, and the backup AC The power supply is connected to the system, and the general-purpose inverter performs power conversion to supply power to the system.
  • the switching and running time of the two backup power sources are allocated by the main controller to complete the automatic switching function of the power grid and the backup power source.
  • FIG. 3 shows a flow of a method 300 for operating a backup power supply according to the present invention, wherein dashed boxes show optional steps.
  • step 301 the grid voltage of the AC grid connected through the third switch is determined.
  • grid voltage can be measured by voltage sensors, voltmeters.
  • a power threshold is determined.
  • the power threshold P threshold can be determined according to the following formula:
  • P threshold P average * a + P peak * (1-a), where 0 ⁇ a ⁇ 1, where P average is the average power required by the power load, which can be counted according to minute-level load data; P peak is the power load The peak power can be counted according to the second-level load data; a is the proportional coefficient, through which the power threshold can be adjusted according to the actual system operating conditions. For example, in the fan auxiliary power supply system, the average value of P is 34kW, the peak value of P is 73kW, a is 0.6, and the threshold value of P can be set to 57kW.
  • the inventor found through research that by adjusting a, the time point of transition from average power to peak power can be adjusted, that is, when the load power reaches a certain point between the average power and peak power, the power of the backup power supply is adjusted to the peak power or above.
  • Research proves that when a takes 0.6 to 0.8, better power transition can be achieved.
  • the ratio between the power of the generator (such as a diesel generator) and the average power of the load of the power supply is greater than or equal to 1:1, and the ratio between the power of the generator and the peak power of the load of the power supply
  • the ratio of is less than or equal to 1:2 (that is, less than or equal to 0.5), in this case, the power of the generator (first sub-power supply) is less than or equal to the power of the battery pack (second sub-power supply).
  • step 303 when the grid voltage is lower than the voltage threshold and the expected output power of the backup power supply is less than or equal to the power threshold, close the first switch and open the second switch to access the first sub-power supply, so that the second A sub-power supply.
  • step 304 when the grid voltage is lower than the voltage threshold and the expected output power of the backup power supply is greater than the power threshold, the first switch and the second switch are closed to access the first sub-power supply and the second sub-power supply, so that the The first sub-power supply and the second sub-power supply jointly supply power, wherein the DC/DC converter works forward to discharge the second sub-power supply.
  • step 305 when the grid voltage is higher than the voltage threshold and the power of the second sub-power supply is lower than the power threshold, close the second switch, wherein the DC/DC converter works in reverse, so that the second sub-power supply is supplied from the AC power grid Charge.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Stand-By Power Supply Arrangements (AREA)
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Abstract

本发明涉及一种备用电源，包括：第一子电源，其被配置为提供交流电能，其中第一子电源连接到AC/DC转换器的输入端；AC/DC转换器，其被配置为将交流电能转换成直流电能，其中所述AC/DC转换器的输出端连接到备用电源的输出端；以及第二子电源，其被配置为提供直流电能，其中第二子电源连接到备用电源的输出端。此外，本发明还涉及该备用电源的运行方法。通过本发明，可以提供可靠性高且能适应风机等功率需求变化较大的负载的用电要求的备用电源方案。

Description

一种备用电源及其运行方法 技术领域
本发明总的来说涉及风力发电机领域，更具体而言，涉及一种备用电源及其运行方法。此外，本发明还涉及一种具有这样的备用电源的风力发电机。
背景技术
近年来，随着各国对环境的重视度提高，清洁能源领域呈现出快速发展的趋势。清洁能源作为一种新型能源，与传统化石燃料相比具有分布广泛、可再生、环境污染小等优点。作为清洁能源的代表，风力发电机的应用日益增长。另外，由于近年来因新冠疫情等不可抗力对人员流动的限制，诸如风力发电机之类无需人员操作亦可长期运行的发电装置的优势愈发凸显。
风力发电机(或简称风机)具有许多需要供电的重要部件，例如变桨轴承、偏航轴承和控制电路等。这些重要部件的稳定供电直接决定了风机的正常运行和运行安全性。通常，这些部件通过交流电网来供电。但是在交流电网发生故障时，必须由备用电源对这些部件进行供电。然而，目前的备用电源难以适应用电负载的较大功率变化。因此，需要一种可靠性高且能适应风机等负载功率变化大、以及在极端条件下、尤其是电网掉电时的用电要求的备用电源。
发明内容
从现有技术出发，本发明的任务是，提供一种融合多个电源的备用电源及其运行方法，通过该备用电源和/或该运行方法，可以提供可靠性高且能适应风机等功率需求波动较大的负载在极端条件下、尤其是电网掉电时的用电要求的备用电源方案。也就是说，本发明既可以适用于电网正常供电时的功率突变，也能适用于极端条件下的功率突变、尤其是电网掉电时的功率突变。
在本发明的第一方面，该任务通过一种备用电源来解决，该备用电源包括：
第一子电源，其被配置为提供交流电能，其中第一子电源连接到AC/DC转换器的输入端；
AC/DC转换器，其被配置为将交流电能转换成直流电能，其中所述AC/DC转换器的输出端连接到备用电源的输出端；以及
第二子电源，其被配置为提供直流电能，其中第二子电源连接到备用电源的输出端。
在本发明的范围内，术语“交流电能”涵盖了交流电流、交流电压和交流功率，并且术语“直流电能”涵盖了直流电流、直流电压和直流功率。术语“AC/DC转换器”涵盖了各种将交流电能转换成直流电能的设备，例如二极管、半波整流器、全波整流器、晶闸管、全控桥等等。术语“子电源”是指能够提供交流或直流电能的各种电设备、例如电池、发电机等，其中子电源尤其是指电网以外的电源、即在极端条件下、尤其是电网掉电时可投入使用的电源。在本发明中，发电机可以涵盖各种类型的发电机、尤其是燃料发电机，例如包括：柴油发电机、氢气发电机、乙醇发电机、化石燃料发电机等等。
在本发明的一个扩展方案中规定，该备用电源还包括：
第一开关，其中第一子电源通过第一开关连接到AC/DC转换器的输入端。
在本发明的另一扩展方案中规定，该备用电源还包括：
DC/DC变换器，其被配置为将直流电能转换成具有不同参数的直流电能，其中所述DC/DC变换器连接在第二子电源与备用电源输出端之间，并且所述DC/DC变换器的输出端通过第二开关连接到备用电源的输出端。
DC/DC变换器不是必需的，例如当第二子电源的输出电能在无需转换即可给负载供电时，不需要DC/DC变换器。相反，当第二子电源的输出电能不能直接给负载供电而是需要转换(例如电流、电压的转换)时，需要采用DC/DC变换器。
在本发明的又一扩展方案中规定：
第一子电源包括下列各项中的一个或多个：
发电机；以及
电池组和直流到交流变换器的组合；以及
第二子电源包括下列各项中的一个或多个：
电池组以及超级电容；以及
发电机和交流到直流变换器的组合。
在本发明的另一扩展方案中规定，所述DC/DC变换器为双向DC/DC变换器，并且其中该备用电源还包括：
第三开关，其中交流电网通过第三开关连接到AC/DC转换器的输入端。
在此，术语双向DC/DC变换器是指，可从该双向DC/DC变换器的输入端或输出端输入直流电能，并在输出端或输入端输出经转换的直流电能。
在本发明的另一扩展方案中规定，第一开关和/或第二开关和/或第三开关包括下列各项之一：功率开关、断路器、接触器、以及继电器。
在本发明的又一扩展方案中规定，该备用电源还包括：
逆变器，其被配置为将直流电能转换成交流电能，其中所述逆变器的输入端与备用电源的输出端连接，并且所述逆变器的输出端连接到负载。
在本发明的一个优选方案中规定，该备用电源还包括控制器，所述控制器被配置为执行下列动作：
在检测到通过第三开关接入的交流电网的电压低于电压阈值时，闭合第一开关和/或第二开关以接入第一子电源和/或第二子电源，其中在闭合第二开关的情况下，DC/DC变换器正向工作，使得第二子电源放电，其中：
在备用电源的所期望的输出功率小于或等于功率阈值时，闭合第一开关并断开第二开关以接入第一子电源；以及
在备用电源的所期望的输出功率大于功率阈值时，闭合第一开关和第二开关以接入第一子电源和第二子电源。
通过该优选方案，可以满足负载的平均功率和峰值功率要求。这基于发明人的如下洞察，发明人通过研究发现，诸如柴油发电机之类的交流备用电源具有较高的能量密度，因此适于为负载提供平均功率，而诸如燃料电池之类的直流备用电源具有较高的响应速度、并联扩容能力和高的功率密度，因此适于为负载提供峰值功率。因此，在负载功率要求较低、即不超过功率阈值时，可采用交流备用电源来为负载提供电能以提供平均功率，并且在负载功率要求较高、即超过功率阈值时，可采用 直流备用电源来为负载提供电能以提供峰值功率。功率阈值可以按照特定的计算方式来确定，以较好地满足负载的功率需求。应当指出，本发明不仅适用于风力发电机领域，而且还适于其它具有用电负载的领域、例如光伏领域(比如利用本发明的备用电源给光伏的控制电路等部件供电)、气象设备领域、照明设施等等。
在本发明的另一优选方案中规定，所述控制器还被配置为执行下列动作：
在检测到通过第三开关接入的交流电网的电压高于电压阈值且第二子电源的电量低于电量阈值时，闭合第二开关，其中DC/DC变换器反向工作，使得从交流电网给第二子电源充电。
通过该优选方案，可以在第二备用电源不使用时给第二备用电源充电，由此实现第二备用电源的随时可用性。
在本发明的第二方面，前述任务通过一种用于运行根据本发明的方法来解决，该方法包括下列步骤：
确定通过第三开关接入的交流电网的电网电压；
在所述电网电压低于电压阈值并且备用电源的所期望的输出功率小于或等于功率阈值时，闭合第一开关并断开第二开关以接入第一子电源，使得由第一子电源供电；
在所述电网电压低于电压阈值并且备用电源的所期望的输出功率大于功率阈值时，闭合第一开关和第二开关以接入第一子电源和第二子电源，使得由第一子电源和第二子电源共同供电，其中DC/DC变换器正向工作，使得第二子电源放电；以及
在所述电网电压高于电压阈值且第二子电源的电量低于电量阈值时，闭合第二开关，其中DC/DC变换器反向工作，使得从交流电网给第二子电源充电。
在本发明的一个优选方案中规定，该方法还包括下列步骤：
根据下列公式确定所述功率阈值P 阈值：
P 阈值＝P 平均*a+P 峰值*(1-a)，其中0≤a≤1，其中P 平均为电源负载所需平均功率，可按照分钟级负载数据进行统计；P 峰值为电源负载的峰值功率，可按照秒级负载数据进行统计；a为比例系数，通过该比例系数可按照实际***运行工况调整功率阈值。
例如，在风机辅助供电***中，P 平均取34kW，P 峰值取73kW，a取0.6， P阈值可设置为57kW。发明人通过研究发现，通过调节a，可以调节从平均功率过渡到峰值功率的时间点，即负载功率在达到平均功率与峰值功率之间的某个点时，即将备用电源的功率调节到峰值功率或以上。a越小，则时间点越提前，反之则越靠后。研究证明，a当a取0.6至0.8时，可实现较好的功率过渡。在一个优选实施例中，发电机(如柴油发电机)的功率与电源的负载的平均功率之间的比例为大于或等于1：1，并且发电机的功率与电源的负载的峰值功率之间的比例为小于或等于1：2(即小于或等于0.5)，在这种情况下，发电机(第一子电源)的功率小于或等于电池组(第二子电源)的功率。由此，无需配备大功率发电机，而是可以配备低功率发电机，由此降低备用电源的成本。
此外，本发明还涉及一种风力发电机，其具有根据本发明的备用电源，其中连接在备用电源的输出端处的负载包括下列各项中的一个或多个：偏航轴承、变桨轴承、以及控制电路。其它负载也是可设想的。例如，在光伏设备的情况下，所述负载可以是光伏控制电路、或者光伏设备中的有源器件等等。
本发明至少具有如下有益效果：本发明人通过研究发现，在诸如风机的用电场景中，如变桨轴承、偏航轴承之类的用电负载因风力等影响因素，其功率可能在平均功率的基础上具有一个跳变或波动、即可能频繁出现峰值功率，因此备用电源需要兼顾负载的平均功率和峰值功率二者，那么在极端条件下、尤其是电网掉电时这些突变的功率需求也应该被满足；本发明人通过进一步研究发现，诸如柴油发电机之类的交流备用电源具有较高的能量密度，因此适于为负载提供平均功率，而诸如燃料电池、超级电容之类的直流备用电源具有较高的响应速度(连通即供电)、并联扩容能力(可无限并联电池扩容)和高的功率密度，因此适于为负载提供峰值功率，因此发明人发现，如果备用电源具有彼此并联的交流备用电源和直流备用电源，则可以较好地兼顾用电负载的平均功率和峰值功率，由此较好地满足负载的用电需要。此外，本发明人还发现，通过合理设置功率阈值来实现从交流电源到直流电源或者交流电源+直流电源的切换，从而较好地、较迅速地实现输出功率瞬变。另外，本发明人通过合理设置电路结构，使得在第二备用电源不使用时能够从交流电网给第二备用电源充电，由此实现第二备用电源的随时可用性。此外，本发明人还令人意想不到地发现，通过本发明的电路设置，负载 是通过变换器(AC/DC转换器、逆变器)连接到交流电网的，这样一来，将负载与前级电网变压器彼此隔离，使得用电单元、即负载经变换器变换以后再连接在直流母线上，由此提高备用电源的***效率，降低了运维成本与硬件投入。
附图说明
下面结合具体实施方式参考附图进一步阐述本发明。
图1示出了本发明的所应用于的风力发电机的示意图；
图2示出了根据本发明的融合多个电源的备用电源的电路图；以及
图3示出了用于运行根据本发明的备用电源的方法的流程。
具体实施方式
应当指出，各附图中的各组件可能为了图解说明而被夸大地示出，而不一定是比例正确的。在各附图中，给相同或功能相同的组件配备了相同的附图标记。
在本发明中，除非特别指出，“布置在…上”、“布置在…上方”以及“布置在…之上”并未排除二者之间存在中间物的情况。此外，“布置在…上或上方”仅仅表示两个部件之间的相对位置关系，而在一定情况下、如在颠倒产品方向后，也可以转换为“布置在…下或下方”，反之亦然。
在本发明中，各实施例仅仅旨在说明本发明的方案，而不应被理解为限制性的。
在本发明中，除非特别指出，量词“一个”、“一”并未排除多个元素的场景。
在本发明中，术语“连接”既可以指两者直接连接，也可以指两者通过中间元件间接地连接。
在此还应当指出，在本发明的实施例中，为清楚、简单起见，可能示出了仅仅一部分部件或组件，但是本领域的普通技术人员能够理解，在本发明的教导下，可根据具体场景需要添加所需的部件或组件。另外，除非另行说明，本发明的不同实施例中的特征可以相互组合。例如，可以用第二实施例中的某特征替换第一实施例中相对应或功能相同或相似的特征，所得到的实施例同样落入本申请的公开范围或记载范围。
在此还应当指出，在本发明的范围内，“相同”、“相等”、“等于”等措辞并不意味着二者数值绝对相等，而是允许一定的合理误差，也就是说，所述措辞也涵盖了“基本上相同”、“基本上相等”、“基本上等于”。以此类推，在本发明中，表方向的术语“垂直于”、“平行于”等等同样涵盖了“基本上垂直于”、“基本上平行于”的含义。
另外，本发明的各方法的步骤的编号并未限定所述方法步骤的执行顺序。除非特别指出，各方法步骤可以以不同顺序执行。
此外，还应当指出，本发明不仅适用于风力发电机领域，而且还适于其它具有用电负载的领域、例如光伏领域(比如利用本发明的备用电源给光伏的控制电路等部件供电)、气象设备领域、照明设施等等。
首先阐述本发明所基于的原理。本发明人通过在风力发电机领域中的长期研究发现，在风机的用电场景中，诸如变桨轴承、偏航轴承之类的用电负载因受风力、调节速度、机械阻力等因素影响，其功率可能在平均功率的基础上具有一个瞬时或短时间跳变、即可能出现峰值功率，因此在极端条件下、尤其是电网掉电时，备用电源也需要兼顾负载的平均功率和峰值功率二者，否则可能出现负载不能正常工作甚至发生故障的情况；本发明人通过进一步研究发现，诸如柴油发电机之类的交流备用电源具有较高的能量密度，因此适于为负载提供平均功率，而诸如燃料电池之类的直流备用电源具有较高的响应速度(连通即供电)、并联扩容能力(可无限并联电池扩容)和高的功率密度，因此适于为负载提供峰值功率，因此发明人发现，如果备用电源具有彼此并联的交流备用电源和直流备用电源，则可以较好地兼顾用电负载的平均功率和峰值功率，由此较好地满足负载的用电需要。此外，本发明人还发现，通过合理设置功率阈值来实现从交流电源到直流电源或者交流电源+直流电源的切换，从而较好地、较迅速地实现输出功率瞬变。另外，本发明人通过合理设置电路结构，使得在第二备用电源不使用时能够从交流电网给第二备用电源充电，由此实现第二备用电源的随时可用性。此外，本发明人还令人意想不到地发现，通过本发明的电路设置，负载是通过变换器(AC/DC转换器、逆变器)连接到交流电网的，这样一来，将负载与前级电网变压器彼此隔离，使得用电单元、即负载经变换器变换以后再连接在直流母线上，由此提高备用电源的***效率，降低了运维成本与硬件投入。
下面结合具体实施方式参考附图进一步阐述本发明。
图1示出了本发明的所应用于的风力发电机100的示意图。图1所示风力发电机100包括塔架101、可旋转地连接到塔架101并且支承轮毂103的机舱102。在轮毂103上布置有两个或更多个叶片104，其中叶片104在风力作用下带动布置在轮毂108中的转子(未示出)绕轴线(未示出)旋转，其中发电机的转子相对于定子的旋转将生成电能。风力发电机100可以包括多种消耗电能的负载，例如变桨轴承、偏航轴承、以及控制电路等等。在正常情况下，风力发电机100的负载通过交流电网来供电，但是在交流电网发生故障或停电的情况下，需要使用备用电源来给这些负载供电，否则，这些负载无法运转。
图2示出了根据本发明的融合多个电源的备用电源200的电路图。
如图2所示，根据本发明的备用电源200包括下列部件，其中一些部件是可选的：
·第一子电源201，其被配置为提供交流电能，交流电能例如包括交流电流、交流电压、以及交流功率。第一子电源通过第一开关203连接到AC/DC转换器206的输入端。第一开关201例如可以是功率开关、断路器、接触器或者继电器。在本实施例中，第一子电源201优选为柴油发电机、例如80kW柴油发电机。燃料发电机由于具有较大的能量密度，因此能够持久地提供平均功率。在本实施例中，仅仅示出了单个第一子电源201。在其它实施例中，也可以设置多个第一子电源201，它们彼此并联。
·AC/DC转换器206，其被配置为将交流电能转换成直流电能，其中所述AC/DC转换器的输出端连接到备用电源的输出端OUT。在本发明中，AC/DC转换器可包括各种将交流电能转换成直流电能的设备，例如二极管、半波整流器、全波整流器、晶闸管、全控桥等等。
·第二子电源202，其被配置为提供直流电能，直流电能例如包括直流电流、直流电压、以及直流功率。第二子电源202连接到直流到直流DC/DC变换器213的输入端或者在无需DC/DC变换器213直接连接到备用电源200的输出端OUT。在本实施例中，示出了两个第二子电源202。在其它实施例中，也可以设置单个或更多个第二子电源202，它们与相应DC/DC变换器213串联后彼此并联。在本实施例中，第二子电源202为彼此串联的多个电池(例如燃料电池或其它电池)，它们可以提供多 倍的电池电压。在其他实施例中，第一子电源202也可以为彼此并联的多个电池(例如燃料电池或其它电池)，以提供多倍的电池电流。并联或串联的电池的数目可以是任意的，例如可以根据平均功率和峰值功率的数值来确定。
·可选的DC/DC变换器213，其被配置为将从第二子电源202输入的直流电能转换成具有不同参数的直流电能，其中所述DC/DC变换器的输出端通过第二开关204连接到备用电源的输出端。第二开关204例如可以是功率开关、断路器、接触器或者继电器。例如，DC/DC变换器213将所输入的直流电能转换成具有不同电流或电压值的直流电能，所述电流和电压的大小可以根据负载的所需功率或额定电流或额定电压来确定。在本实施例中，示出了两个DC/DC变换器213。在其它实施例中，也可以设置单个或更多个DC/DC变换器213，它们与相应第二子电源202串联后彼此并联。DC/DC变换器213尤其是双向DC/DC变换器，其中双向DC/DC变换器是指，既可以从该双向DC/DC变换器的输入端直流电能(正向工作)，并在输出端输出经转换的直流电能，也可以从该双向DC/DC变换器的输出端输入直流电能，并在输入端输出经转换的直流电能(反向工作)。
·可选的第三开关205，其中交流电网208通过第三开关205连接到AC/DC转换器206的输入端。第三开关205例如可以是功率开关、断路器、接触器或者继电器。通过相应的控制，交流电网208既可以给负载供电，也可以给第一和/或第二子电源充电。
·可选的逆变器207，其被配置为将直流电能转换成交流电能。所述逆变器207的输入端与备用电源的输出端OUT连接，并且所述逆变器的输出端连接到负载。在此，在逆变器207的两个输入端子之间可以连接电容210。电容210例如可以抑制从电网或子电源中输入的电能中的高频杂波/谐波，也可以吸收电路中的电感性负载的无功电流。此外，在AC/DC转换器206的输出端处可以设置预充电电路211，其包括开关和与该开关并联的保险装置。预充电电路211的作用是，在预充电时(该开关断开)确保预充电电流不超过阈值，以避免损坏电路中的部件。逆变器207可以设置多个，以分别为不同的交流负载209供电。在此，交流负载209例如为偏航电机和控制电路。
·可选的控制器(未示出)，所述控制器被配置为执行下列动作：
在检测到通过第三开关205接入的交流电网208的电压低于电压阈值时(例如停电时)，闭合第一开关203和/或第二开关204以接入第一子电源203和/或第二子电源204，其中在闭合第二开关204的情况下，DC/DC变换器213正向工作，使得第二子电源202放电，其中：
在备用电源200的所期望的输出功率(例如为负载209的额定功率)小于或等于功率阈值时，闭合第一开关203并断开第二开关204以接入第一子电源201；以及
在备用电源200的所期望的输出功率(例如为负载209的峰值功率)大于功率阈值时，闭合第一开关203和第二开关204以接入第一子电源201和第二子电源202；以及
在检测到通过第三开关205接入的交流电网208的电压高于电压阈值且第二子电源202的电量低于电量阈值时，闭合第二开关204，其中DC/DC变换器213反向工作，使得从交流电网208给第二子电源202充电。
下面阐述根据本发明的备用电源200的工作流程。
电网正常模式
在交流电网208正常供电时，闭合第三开关205，使得交流电网208的交流电能经整流器206整流和逆变器207逆变以后再给交流负载209供电。由此可将通过变换器将交流负载209与交流电网208彼此隔离，由此消除了上级变压器产生的高次谐波、杂波等有害电信号，避免交流负载209受损。
充电模式
当交流电网208正常供电且第一或第二子电源201和/或202需要充电时(例如其电量低于电量阈值)，闭合第一开关203和/或第二开关204，此时DC/DC转换器213工作在反向模式，使得从交流电网208给第一子电源202充电。当不需要充电时，可断开第一开关203和/或第二开关204。这种反向充电可使得子电源随时都可以被充电，并随时处于可用状态。
放电模式
在极端条件下、尤其是交流电网掉电时、即在交流电网208不能供电时，闭合第一开关203和/或第二开关204以接入第一子电源201和/或第二子电源202。当负载所需功率小于或等于功率阈值时，可仅接入 第一子电源201。当负载所需功率大于阈值功率时，可以接入第一和第二子电源201和202二者。
下面以海上风力发电机为例阐述本发明的备用电源的运行方法。
海上风电发电机的抗台风偏航后备电源应用：
当海上风力发电机遇上台风电网失电情况时，可切换到本发明的后备电源，以驱动偏航***正常运行，降低整机载荷，大幅提升海上风电机组可靠性。后备电源的启停机状态如下：
1)启机及运行：海上风机400Vac上电，变频器常闭软启为母线电压Udc预充电，Udc建立后，逆变电源自动启动为控制***供电，控制***上电启动后控制直流接触器闭合，完成母线电压建立过程，随后偏航***跟随主控指令正常偏航运行，双向DCDC变换器根据电池电压进行充电，在此可采用滞环控制方式，避免反复给电池充电。
2)电网掉电切换后备电源：400Vac断电，Udc下降至双向DCDC变换器启动放电阈值时，电池和双向DCDC变换器为母线供电；电网断路器断开，后备交流电源断路器闭合，后备交流电源接入***，由通用变频器进行电能变换给***供电。两种后备电源切换及运行时长由主控调配，完成电网和后备电源自动切换功能。
3)断电：400Vac断电，同时停止双向DCDC变换器放电功能，断开DC回路开关，实现***断电，注意后备电源依然有电。
图3示出了用于运行根据本发明的备用电源的方法300的流程，其中虚线框示出了可选步骤。
在步骤301，确定通过第三开关接入的交流电网的电网电压。例如，可以通过电压传感器、电压表来测量电网电压。
在可选步骤302，确定功率阈值。例如可以根据下列公式确定所述功率阈值P 阈值：
P 阈值＝P 平均*a+P 峰值*(1-a)，其中0≤a≤1，其中P 平均为电源负载所需平均功率，可按照分钟级负载数据进行统计；P 峰值为电源负载的峰值功率，可按照秒级负载数据进行统计；a为比例系数，通过该比例系数可按照实际***运行工况调整功率阈值。例如，在风机辅助供电***中，P 平均取34kW，P 峰值取73kW，a取0.6，P阈值可设置为57kW。发明人通过研究发现，通过调节a，可以调节从平均功率过渡到峰值功率的时间点，即负载功率在达到平均功率与峰值功率之间的某个点时，即将备用电源 的功率调节到峰值功率或以上。a越小，则时间点越提前，反之则越靠后。研究证明，a当a取0.6至0.8时，可实现较好的功率过渡。在一个优选实施例中，发电机(如柴油发电机)的功率与电源的负载的平均功率之间的比例为大于或等于1：1，并且发电机的功率与电源的负载的峰值功率之间的比例为小于或等于1：2(即小于或等于0.5)，在这种情况下，发电机(第一子电源)的功率小于或等于电池组(第二子电源)的功率。由此，无需配备大功率发电机，而是可以配备低功率发电机，由此降低备用电源的成本。
在步骤303，在所述电网电压低于电压阈值并且备用电源的所期望的输出功率小于或等于功率阈值时，闭合第一开关并断开第二开关以接入第一子电源，使得由第一子电源供电。
在步骤304，在所述电网电压低于电压阈值并且备用电源的所期望的输出功率大于功率阈值时，闭合第一开关和第二开关以接入第一子电源和第二子电源，使得由第一子电源和第二子电源共同供电，其中DC/DC变换器正向工作，使得第二子电源放电。
在步骤305，在所述电网电压高于电压阈值且第二子电源的电量低于电量阈值时，闭合第二开关，其中DC/DC变换器反向工作，使得从交流电网给第二子电源充电。
虽然本发明的一些实施方式已经在本申请文件中予以了描述，但是本领域技术人员能够理解，这些实施方式仅仅是作为示例示出的。本领域技术人员在本发明的教导下可以想到众多的变型方案、替代方案和改进方案而不超出本发明的范围。所附权利要求书旨在限定本发明的范围，并由此涵盖这些权利要求本身及其等同变换的范围内的方法和结构。

Claims (13)

  1. 一种备用电源，包括：
    第一子电源，其被配置为提供交流电能，其中第一子电源连接到AC/DC转换器的输入端；
    AC/DC转换器，其被配置为将交流电能转换成直流电能，其中所述AC/DC转换器的输出端连接到备用电源的输出端；以及
    第二子电源，其被配置为提供直流电能，其中第二子电源连接到备用电源的输出端。
  2. 根据权利要求1所述的备用电源，还包括：
    第一开关，其中第一子电源通过第一开关连接到AC/DC转换器的输入端。
  3. 根据权利要求2所述的备用电源，还包括：
    DC/DC变换器，其被配置为将直流电能转换成具有不同参数的直流电能，其中所述DC/DC变换器的输入端与第二子电源连接，并且所述DC/DC变换器的输出端通过第二开关连接到备用电源的输出端。
  4. 根据权利要求1所述的备用电源，其中：
    第一子电源包括下列各项中的一个或多个：
    发电机；以及
    电池组和直流到交流变换器的组合；以及
    第二子电源包括下列各项中的一个或多个：
    电池组、超级电容；以及
    发电机和交流到直流变换器的组合。
  5. 根据权利要求3所述的备用电源，其中所述DC/DC变换器为双向DC/DC变换器，并且其中该备用电源还包括：
    第三开关，其中交流电网通过第三开关连接到AC/DC转换器的输入端。
  6. 根据权利要求1所述的备用电源，其中第一开关和/或第二开关和/或第三开关包括下列各项之一：功率开关、断路器、接触器、以及继电器。
  7. 根据权利要求1所述的备用电源，还包括：
    逆变器，其被配置为将直流电能转换成交流电能，其中所述逆变器的输入端与备用电源的输出端连接，并且所述逆变器的输出端连接到负 载。
  8. 根据权利要求3所述的备用电源，还包括控制器，所述控制器被配置为执行下列动作：
    在检测到通过第三开关接入的交流电网的电压低于电压阈值时，闭合第一开关和/或第二开关以接入第一子电源和/或第二子电源，其中在闭合第二开关的情况下，DC/DC变换器正向工作，使得第二子电源放电，其中：
    在备用电源的所期望的输出功率小于或等于功率阈值时，闭合第一开关并断开第二开关以接入第一子电源；以及
    在备用电源的所期望的输出功率大于功率阈值时，闭合第一开关和第二开关以接入第一子电源和第二子电源。
  9. 根据权利要求8所述的备用电源，其中所述控制器还被配置为执行下列动作：
    在检测到通过第三开关接入的交流电网的电压高于电压阈值且第二子电源的电量低于电量阈值时，闭合第二开关，其中DC/DC变换器反向工作，使得从交流电网给第二子电源充电；和/或
    在检测到通过第三开关接入的交流电网的电压低于电压阈值且第二子电源的电量低于电量阈值时，闭合第一开关和第二开关，其中DC/DC变换器反向工作，使得从第一子电源给第二子电源充电。
  10. 一种用于运行根据权利要求1至9之一所述的备用电源的方法，包括下列步骤：
    确定通过第三开关接入的交流电网的电网电压；
    在所述电网电压低于电压阈值并且备用电源的所期望的输出功率小于或等于功率阈值时，闭合第一开关或第二开关以接入第一子电源或第二子电源，使得由第一子电源或第二子电源供电；
    在所述电网电压低于电压阈值并且备用电源的所期望的输出功率大于功率阈值时，闭合第一开关和第二开关以接入第一子电源和第二子电源，使得由第一子电源和第二子电源共同供电，其中DC/DC变换器正向工作，使得第二子电源放电；以及
    在所述电网电压高于电压阈值且第二子电源的电量低于电量阈值时，闭合第二开关，其中DC/DC变换器反向工作，使得从交流电网给第二子电源充电。
  11. 根据权利要求10所述的方法，还包括下列步骤：
    根据下列公式确定所述功率阈值P 阈值：
    P 阈值＝P 平均*a+P 峰值*(1-a)，其中0≤a≤1，其中P 平均为电源负载所需平均功率，按照分钟级负载数据进行统计；P 峰值为电源负载的峰值功率，按照秒级负载数据进行统计；a为比例系数，通过该比例系数调整功率阈值。
  12. 一种风力发电机，其具有根据权利要求1至9之一所述的备用电源，其中连接在备用电源的输出端处的负载包括下列各项中的一个或多个：偏航轴承、变桨轴承、以及控制电路。
  13. 一种新能源设备，其具有根据权利要求1至9之一所述的备用电源。
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