WO2012119300A1 - Hierarchical active and reactive power control system in electric vehicle charging stations and method thereof - Google Patents

Hierarchical active and reactive power control system in electric vehicle charging stations and method thereof Download PDF

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Publication number
WO2012119300A1
WO2012119300A1 PCT/CN2011/071567 CN2011071567W WO2012119300A1 WO 2012119300 A1 WO2012119300 A1 WO 2012119300A1 CN 2011071567 W CN2011071567 W CN 2011071567W WO 2012119300 A1 WO2012119300 A1 WO 2012119300A1
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WIPO (PCT)
Prior art keywords
reactive power
active
charging
voltage
charging unit
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PCT/CN2011/071567
Other languages
French (fr)
Inventor
Yao Chen
Qianjin Liu
Chengyan YUE
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Abb Research Ltd.
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Priority to PCT/CN2011/071567 priority Critical patent/WO2012119300A1/en
Publication of WO2012119300A1 publication Critical patent/WO2012119300A1/en

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Classifications

    • 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
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/14—Conductive energy transfer
    • 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
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
    • H02J3/1835—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control
    • H02J3/1842—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/20—Active power filtering [APF]
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • 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
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • 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
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • 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
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles

Definitions

  • the invention relates to the field of power system and more particularly to a power control system in electric vehicle (EV) charging stations and the method thereof.
  • EV electric vehicle
  • the electromotor also named as electric motor
  • rechargeable battery packs Compared with internal combustion engines (ICEs), the electromotor has several advantages as follows.
  • Electromotor provides quiet and smooth operation, stronger acceleration, and less maintenance than ICEs.
  • Fig.1 illustrates a typical circuit topology of a four-quadrant electric vehicle battery charger.
  • such topology consists of four-quadrant PWM rectifier and bi-directional DC/DC converter.
  • the active rectifier can achieve controllable power factor regulation in the whole operation range, which gives the possibilities of battery chargers to provide reactive power support to the grid.
  • the low-order harmonics can be well suppressed by PWM (Pulse-Width Modulation) controls, and thus improves the power quality of ordinary battery charger.
  • a hierarchical active and reactive power control system in electric vehicle charging stations comprises a plurality of charging units and a central controller configured to calculate the corresponding capacity margin of each charging unit based on the active and reactive power of each charging unit, calculate the active and reactive power increment of each charging unit based on the external dispatch command and the calculated capacity margin, and send said increment to each local controller; the system further comprises a local controller in each charging unit, configured to measure the active and reactive power of the relevant charging units and send the measuring results to the central controller, measure the line-side frequency and voltage, and adjust the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage as well as the increment from the central controller.
  • the central controller comprises a communication unit configured to receive the external dispatch command and communicate with local controllers; and a calculating unit configured to calculate the capacity margin of each charging unit and the active and reactive power increment of each charging unit.
  • each local controller comprises: a measuring unit configured to measure the active and reactive power of each charging unit and the line-side frequency and voltage; and a communication unit configured to send the active and reactive power of each charging unit to the central controller and receiving the active and reactive power increment; an adjusting unit configured to regulate the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage and the increment from the central controller.
  • the local controller is configured to balance the less and more frequent deviation about the frequency and/or voltage.
  • the deviation is caused by near-by charging units, the charging stations or the other loads.
  • the central controller is configured to utilize the available capacities of all charging units so as to regulate the power grid frequency and the voltage supply.
  • the system comprises a plurality of local controllers.
  • the system comprises no less than one central controller.
  • a hierarchical active and reactive power control method in electric vehicle charging stations comprises: measuring, by the local controller, the active and reactive power of the relevant charging units; and sending the measuring results to the central controller; measuring, by the local controller, the line-side frequency and voltage; calculating, by the central controller, the corresponding capacity margin of each charging unit based on the active and reactive power of each charging units; and calculating the active and reactive power increment of each charging unit based on the external dispatch command and the calculated capacity margin; sending the increment to each local controller; and adjusting, by the local controller, the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage and the increment from the central controller.
  • adjusting the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage comprising the following step: increasing the active power proportionally when frequency increases and vice-versa; increasing the inductive reactive power proportionally when voltage increases, and increasing the capacitive reactive power proportionally when voltage decreases.
  • the method further comprises allocating the active and reactive power increment proportionally to each charging unit based on its capacity margin.
  • the method further comprises allocating the active and reactive power increment to each charging unit based on its priority and its capacity margin.
  • the local controller is configured to balance less and more frequent deviation about the frequency and/or voltage.
  • the deviation is caused by near-by charging units, charging stations or other loads.
  • the central controller is configured to utilize the available capacities of all charging units so as to regulate the power grid frequency and the voltage supply.
  • Embodiments of the present invention provide a hierarchical active and reactive power control system in electric vehicle charging stations and method thereof, which realize hierarchical active and reactive power control based on four-quadrant battery charging units.
  • this invention can not only take fully utilization of the energy stored in batteries for power system frequency regulation, but also adopt the embedded power factor correction capability of four-quadrant battery chargers for power system reactive power compensation and voltage support.
  • Fig.1 illustrates a typical circuit topology of a four-quadrant electric vehicle battery charger
  • Fig.2 illustrates a representative radial network with EV charging station
  • Fig.3 illustrates a configuration of hierarchical active and reactive power control system in EV charging stations according to an embodiment of the present invention
  • Fig.4 illustrates the droop characteristics of a local controller P/Q regulation
  • Fig.5 illustrates a flowchart of the hierarchical active and reactive power control method in EV charging stations according to an embodiment of the present invention
  • Fig.6 illustrates a possible application configuration of load-side hierarchical active and reactive power control system according to an embodiment of the present invention.
  • Fig.2 illustrates a representative radial network with EV charging station.
  • each battery will be charged generally according to the desired charging approach, e.g. the rapid charging, the intermediate charging, the slow overnight charging, etc.
  • the chargers no critical requirement is needed on charging time, so that it's possible for the chargers to adjust their active power consumption within a certain range by grid-side frequency regulation.
  • a charging unit can always be configured for each battery with required capacity redundancy. Together with the stand-by chargers, such available capacities can be adopted for reactive power compensation and voltage support.
  • Fig.3 illustrates a configuration of hierarchical active and reactive power control system in EV charging stations according to an embodiment of the present invention.
  • the hierarchical active and reactive power control system in EV charging station is configured with four-quadrant battery charging units.
  • the hierarchical active and reactive power control system in comprises a plurality of charging units, a central controller, and a plurality of local controller, in which:
  • the local controller in each charging unit is configured to measure the active and reactive power (e.g. Pi , Q-i) of the relevant charging units and send the measuring results to the central controller, measure the line-side frequency (e.g. f) and voltage (e.g. U), and adjust the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage as well as the increment (e.g. ⁇ *, AQi*) from the central controller.
  • the active and reactive power e.g. Pi , Q-i
  • the local controller in each charging unit is configured to measure the active and reactive power (e.g. Pi , Q-i) of the relevant charging units and send the measuring results to the central controller, measure the line-side frequency (e.g. f) and voltage (e.g. U), and adjust the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage as well as the increment (e.g. ⁇ *, AQi*) from the central controller.
  • the increment e.g
  • the central controller is configured to calculate the corresponding capacity margin (e.g. P, Q) of each charging unit based on the active and reactive power of each charging unit, calculate the active and reactive power increment (e.g. ⁇ *, AQi*) of each charging unit based on the external dispatch command and the calculated capacity margin, and send said increment to each local controller.
  • the corresponding capacity margin e.g. P, Q
  • the active and reactive power increment e.g. ⁇ *, AQi*
  • Fig.4 illustrates the droop characteristics of a local controller P/Q regulation. Based on preset droop characteristics shown in Fig.4, incremental active and reactive power components ⁇ * and Aq* will be generated and added onto the previous control settings of battery chargers.
  • the local controller is configured to balance the less and more frequent deviation about the frequency and/or voltage, i.e. the diagonal region shown in Fig 4. The above mentioned deviation is caused by near-by chargers such as the charging units, charging stations or other loads. More details will be explained in the following regulation method shown in Fig.5
  • the central controller comprises: a communication unit and a calculating unit, in which the communication unit is configured to receive the external dispatch command and communicate with local controllers; and the calculating unit is configured to calculate the capacity margin of each charging unit and the active and reactive power increment of each charging unit.
  • each local controller comprises: a measuring unit, a communication unit and an adjusting unit; in which, the measuring unit is configured to measure the active and reactive power of each charging unit and the line-side frequency and voltage; the communication unit is configured to send the active and reactive power of each charging unit to the central controller and receiving the active and reactive power increment; and the adjusting unit is configured to regulate the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage and the increment from the central controller.
  • the hierarchical active and reactive power control system comprises a plurality of local controllers. What's more, the system comprises no less than one central controller.
  • the system may comprise only one central controller, which is configured to utilize the available capacities of all charging units so as to regulation the power grid frequency and voltage supply.
  • the system can contain more than one central controller in order to regulate so many charging units and fully take advantages of the energy supplied in electric grid.
  • Fig.5 illustrates a flowchart of the hierarchical active and reactive power control method in EV charging stations according to an embodiment of the present invention.
  • a hierarchical active and reactive power control method 500 in electric vehicle charging stations comprises:
  • Step 502 measuring the active and reactive power (e.g. Pi , Qi) of the relevant charging units; and sending the measuring results to the central controller by the local controller.
  • active and reactive power e.g. Pi , Qi
  • Step 504 measuring, by the local controller, the line-side frequency (e.g. f) and voltage (e.g. U).
  • the line-side frequency e.g. f
  • voltage e.g. U
  • Step 506 calculating, by the central controller, the corresponding capacity margin of each charging unit (P, Q, e.g. Mrg P,, Mrg Q,) based on the active and reactive power of each charging units.
  • Step 508 determining whether a dispatch command is received by the central controller? If so, perform the step 510; otherwise, jump to the step 502, i.e. continue to perform the real time data acquisition of P, Q out puts of each charging unit. Step 510, calculating the active and reactive power increment (e.g. ⁇ * ,
  • Step 512 sending the increment to each local controller.
  • Step 514 adjusting the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage and the increment from the central controller by the local controller.
  • the step 514 further comprises the following steps:
  • Step 514.1 increasing the active power proportionally when line-side frequency increases and vice-versa.
  • Step 514.2 increasing the inductive reactive power proportionally as the line-side voltage increases, and increasing the capacitive reactive power proportionally as the line-side voltage decreases.
  • the method allocates the active and reactive power increment to each charging unit based on the predefined criteria, e.g. allocating the active and reactive power increment proportionally to each charging unit base on its capacity margin; or allocating the active and reactive power increment to each charging unit based on its priority and its capacity margin.
  • An embodiment of the present invention provides a hierarchical active and reactive power control method in electric vehicle charging stations.
  • the local controller is configured to balance the less and more frequent deviation about the frequency and/or voltage. Such deviation is caused by near-by charging units, charging stations or other loads.
  • the central controller is configured to utilize the available capacities of all charging units so as to regulation the power grid frequency and voltage supply.
  • Fig.6 illustrates a possible application configuration of load-side hierarchical active and reactive power control system according to an embodiment of the present invention.
  • VFDs Variable Frequency Drives
  • the co-generators of industry power plants, large-scale industrial motors fed by Variable Frequency Drives (VFDs), and even some of the household appliances are feasible to realize active or reactive power regulation can all be integrated into such control system.
  • VFDs Variable Frequency Drives
  • both power grid and the equipment owners will benefit from the proposed solutions.
  • the proposed embodiments of the present invention provide the hierarchical active and reactive power control system and methods thereof. Adopt the spirit of the innovation, the Power grid, EV charging stations and EV owners can all benefit from the proposed solutions.
  • the dispersed energy storage devices can be fully utilized for primary/secondary frequency regulation; the embed power factor control capability of four-quadrant battery charging units can be further adopted to provide reactive power compensation and dynamic voltage support; furthermore, large-scale EV charging station can even contribute for peak shaving, grid stability enhancement and possibly proliferation of intermittent renewable energy generation integration.

Abstract

A hierarchical active and reactive power control system in electric vehicle charging stations and a method thereof. The system and the method take fully utilization of the energy stored in batteries, and compensate voltage or frequency deviations. The method comprises the following steps: measuring, by a local controller, the active and reactive power of relevant charging units; sending the measured results to a central controller; measuring, by the local controller, a line-side frequency and voltage; calculating, by the central controller, a corresponding capacity margin of each charging unit based on the active and reactive power of each charging units; calculating an active and reactive power increment of each charging unit based on an external dispatch command and the calculated capacity margin (510); sending the increment to each local controller; adjusting, by each local controller, the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage and the increment from the central controller.

Description

HIERARCHICAL ACTIVE AND REACTIVE POWER CONTROL SYSTEM IN ELECTRIC VEHICLE CHARGING STATIONS AND METHOD THEREOF
FIELD OF THE INVENTION
The invention relates to the field of power system and more particularly to a power control system in electric vehicle (EV) charging stations and the method thereof.
BACKGROUND OF THE INVENTION
Electric Vehicles are greatly propelled by the electromotor (also named as electric motor) powered by rechargeable battery packs. Compared with internal combustion engines (ICEs), the electromotor has several advantages as follows.
1 ) High energy efficiency: the electromotor converts about 75% of the chemical energy stored in the batteries to power the wheels, while ICEs convert 20% of the energy released from gasoline. 2) Environmental friendship: No tailpipe pollutant is emitted by EVs, although the power plant may emit when producing the electricity. However no air pollutant will be produced, if electricity generated from green energy such as from nuclear-, hydro-, solar-, or wind-powered plants.
3) Performance benefits: Electromotor provides quiet and smooth operation, stronger acceleration, and less maintenance than ICEs.
4) Reductive energy dependency: Electricity is a convenient energy source, which is available in each commercial construction or domestic apartment.
The significant limiting factors for EV development are battery-related challenges, e.g. duration period, driving range, recharge time, battery cost, bulk and weight, etc. With the development of energy storage technologies, batteries are gradually approaching practical cost and performance; what's more, charging properties strongly have stimulated the fast growth of EV business and made electricity a preferred energy source for new generations of road vehicles.
Unfortunately, a major new challenge in electric power systems gradually reveals itself, i.e. the future integration of a substantial number of EVs into the electric grid. With the wide applications of EV charging units, the impacts on power systems especially on distribution networks will gradually become the most attractive concerns, such as harmonic pollutions caused by AC-DC conversion, voltage drops caused by ultra fast charging, overload issues of existing power system facilities caused by simultaneous charging in residential areas.
Generically, standard diode bridges are adopted in EV battery chargers for AC-DC conversions, and then DC-DC converters will be used to match the desired voltage level of batteries. The advantages of such circuit topology include low cost, simple controlling system design, convenient maintenance, etc. However, it only allows mono-directional power flow from the electric grid to a battery. Besides, low-order harmonics are not avoidable by such topology and thus lead to a series of undesired problems.
If active rectifier and bi-directional DC-DC converter are adopted, four-quadrant operation of battery chargers can be realized. Fig.1 illustrates a typical circuit topology of a four-quadrant electric vehicle battery charger. As shown in Fig.1 , such topology consists of four-quadrant PWM rectifier and bi-directional DC/DC converter. Compared with diode bridges, such topology can realize bi-directional power flow regulation, which means the battery can not only absorb active power from the grid during charging process but also feed the energy back into the grid by discharging when needed. Moreover, the active rectifier can achieve controllable power factor regulation in the whole operation range, which gives the possibilities of battery chargers to provide reactive power support to the grid. Meanwhile, the low-order harmonics can be well suppressed by PWM (Pulse-Width Modulation) controls, and thus improves the power quality of ordinary battery charger.
According to the prior arts about the electric vehicle charging technique, existed solutions cannot take fully utilization of the energy stored in batteries for power system frequency regulation, furthermore cannot provide the correct capability of four-quadrant battery chargers for power system reactive power compensation and voltage support. Such drawbacks decrease the energy utilization efficiency, the charging reliability in desired charging period and performance benefits of the grid.
SUMMARY OF THE INVENTION
To overcome above mentioned shortcomings, the present invention provides a hierarchical active and reactive power control system in electric vehicle charging stations and the method thereof. According to one aspect of the present invention, a hierarchical active and reactive power control system in electric vehicle charging stations is provided. The system comprises a plurality of charging units and a central controller configured to calculate the corresponding capacity margin of each charging unit based on the active and reactive power of each charging unit, calculate the active and reactive power increment of each charging unit based on the external dispatch command and the calculated capacity margin, and send said increment to each local controller; the system further comprises a local controller in each charging unit, configured to measure the active and reactive power of the relevant charging units and send the measuring results to the central controller, measure the line-side frequency and voltage, and adjust the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage as well as the increment from the central controller.
According to a preferred embodiment of the present invention, the central controller comprises a communication unit configured to receive the external dispatch command and communicate with local controllers; and a calculating unit configured to calculate the capacity margin of each charging unit and the active and reactive power increment of each charging unit.
According to a preferred embodiment of the present invention, each local controller comprises: a measuring unit configured to measure the active and reactive power of each charging unit and the line-side frequency and voltage; and a communication unit configured to send the active and reactive power of each charging unit to the central controller and receiving the active and reactive power increment; an adjusting unit configured to regulate the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage and the increment from the central controller.
According to a preferred embodiment of the present invention, the local controller is configured to balance the less and more frequent deviation about the frequency and/or voltage.
According to a preferred embodiment of the present invention, the deviation is caused by near-by charging units, the charging stations or the other loads.
According to a preferred embodiment of the present invention, the central controller is configured to utilize the available capacities of all charging units so as to regulate the power grid frequency and the voltage supply. According to a preferred embodiment of the present invention, the system comprises a plurality of local controllers.
According to a preferred embodiment of the present invention, the system comprises no less than one central controller.
According to another aspect of the present invention, a hierarchical active and reactive power control method in electric vehicle charging stations is provided. The method comprises: measuring, by the local controller, the active and reactive power of the relevant charging units; and sending the measuring results to the central controller; measuring, by the local controller, the line-side frequency and voltage; calculating, by the central controller, the corresponding capacity margin of each charging unit based on the active and reactive power of each charging units; and calculating the active and reactive power increment of each charging unit based on the external dispatch command and the calculated capacity margin; sending the increment to each local controller; and adjusting, by the local controller, the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage and the increment from the central controller. According to a preferred embodiment of the present, adjusting the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage comprising the following step: increasing the active power proportionally when frequency increases and vice-versa; increasing the inductive reactive power proportionally when voltage increases, and increasing the capacitive reactive power proportionally when voltage decreases.
According to a preferred embodiment of the present, the method further comprises allocating the active and reactive power increment proportionally to each charging unit based on its capacity margin.
According to a preferred embodiment of the present invention, the method further comprises allocating the active and reactive power increment to each charging unit based on its priority and its capacity margin.
According to a preferred embodiment of the present invention, the local controller is configured to balance less and more frequent deviation about the frequency and/or voltage.
According to a preferred embodiment of the present invention, the deviation is caused by near-by charging units, charging stations or other loads.
According to a preferred embodiment of the present invention, the central controller is configured to utilize the available capacities of all charging units so as to regulate the power grid frequency and the voltage supply.
Embodiments of the present invention provide a hierarchical active and reactive power control system in electric vehicle charging stations and method thereof, which realize hierarchical active and reactive power control based on four-quadrant battery charging units. With the combination of both local and central controllers, this invention can not only take fully utilization of the energy stored in batteries for power system frequency regulation, but also adopt the embedded power factor correction capability of four-quadrant battery chargers for power system reactive power compensation and voltage support. BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter of the invention will be explained in more details in the following description with reference to preferred exemplary embodiments which are illustrated in the drawings, in which: Fig.1 illustrates a typical circuit topology of a four-quadrant electric vehicle battery charger;
Fig.2 illustrates a representative radial network with EV charging station;
Fig.3 illustrates a configuration of hierarchical active and reactive power control system in EV charging stations according to an embodiment of the present invention;
Fig.4 illustrates the droop characteristics of a local controller P/Q regulation;
Fig.5 illustrates a flowchart of the hierarchical active and reactive power control method in EV charging stations according to an embodiment of the present invention;
Fig.6 illustrates a possible application configuration of load-side hierarchical active and reactive power control system according to an embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Exemplary embodiments of the present invention are described in conjunction with the accompanying drawings hereinafter. For the sake of clarity and conciseness, not all the features of actual implementations are described in the specification.
Fig.2 illustrates a representative radial network with EV charging station. As shown in Fig.2, each battery will be charged generally according to the desired charging approach, e.g. the rapid charging, the intermediate charging, the slow overnight charging, etc. For batteries, no critical requirement is needed on charging time, so that it's possible for the chargers to adjust their active power consumption within a certain range by grid-side frequency regulation. By means of the standard design process, a charging unit can always be configured for each battery with required capacity redundancy. Together with the stand-by chargers, such available capacities can be adopted for reactive power compensation and voltage support. Fig.3 illustrates a configuration of hierarchical active and reactive power control system in EV charging stations according to an embodiment of the present invention. As shown in Fig.3, the hierarchical active and reactive power control system in EV charging station is configured with four-quadrant battery charging units. The hierarchical active and reactive power control system in comprises a plurality of charging units, a central controller, and a plurality of local controller, in which:
The local controller in each charging unit, is configured to measure the active and reactive power (e.g. Pi , Q-i) of the relevant charging units and send the measuring results to the central controller, measure the line-side frequency (e.g. f) and voltage (e.g. U), and adjust the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage as well as the increment (e.g. ΔΡί*, AQi*) from the central controller.
The central controller is configured to calculate the corresponding capacity margin (e.g. P, Q) of each charging unit based on the active and reactive power of each charging unit, calculate the active and reactive power increment (e.g. ΔΡί*, AQi*) of each charging unit based on the external dispatch command and the calculated capacity margin, and send said increment to each local controller.
According to a preferred embodiment of the present invention, in local controllers, the real-time measurement of line-side voltage will be carried out for frequency and voltage magnitude calculation. Fig.4 illustrates the droop characteristics of a local controller P/Q regulation. Based on preset droop characteristics shown in Fig.4, incremental active and reactive power components Δρ* and Aq* will be generated and added onto the previous control settings of battery chargers. In particular, the local controller is configured to balance the less and more frequent deviation about the frequency and/or voltage, i.e. the diagonal region shown in Fig 4. The above mentioned deviation is caused by near-by chargers such as the charging units, charging stations or other loads. More details will be explained in the following regulation method shown in Fig.5
According to a preferred embodiment of the present invention, the central controller comprises: a communication unit and a calculating unit, in which the communication unit is configured to receive the external dispatch command and communicate with local controllers; and the calculating unit is configured to calculate the capacity margin of each charging unit and the active and reactive power increment of each charging unit. According to a preferred embodiment of the present invention, each local controller comprises: a measuring unit, a communication unit and an adjusting unit; in which, the measuring unit is configured to measure the active and reactive power of each charging unit and the line-side frequency and voltage; the communication unit is configured to send the active and reactive power of each charging unit to the central controller and receiving the active and reactive power increment; and the adjusting unit is configured to regulate the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage and the increment from the central controller.
According to a preferred embodiment of the present invention, the hierarchical active and reactive power control system comprises a plurality of local controllers. What's more, the system comprises no less than one central controller.
For example, the system may comprise only one central controller, which is configured to utilize the available capacities of all charging units so as to regulation the power grid frequency and voltage supply. For some large scale and complex electric vehicle charging station, the system can contain more than one central controller in order to regulate so many charging units and fully take advantages of the energy supplied in electric grid.
Fig.5 illustrates a flowchart of the hierarchical active and reactive power control method in EV charging stations according to an embodiment of the present invention. As shown in Fig.5, a hierarchical active and reactive power control method 500 in electric vehicle charging stations comprises:
Step 502, measuring the active and reactive power (e.g. Pi , Qi) of the relevant charging units; and sending the measuring results to the central controller by the local controller.
Step 504, measuring, by the local controller, the line-side frequency (e.g. f) and voltage (e.g. U).
Step 506, calculating, by the central controller, the corresponding capacity margin of each charging unit (P, Q, e.g. Mrg P,, Mrg Q,) based on the active and reactive power of each charging units.
Step 508, determining whether a dispatch command is received by the central controller? If so, perform the step 510; otherwise, jump to the step 502, i.e. continue to perform the real time data acquisition of P, Q out puts of each charging unit. Step 510, calculating the active and reactive power increment (e.g. ΔΡί*,
AQi*) of each charging unit based on the external dispatch command and the calculated capacity margin.
Step 512, sending the increment to each local controller.
Step 514, adjusting the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage and the increment from the central controller by the local controller.
According to an embodiment of the present invention, the step 514 further comprises the following steps:
Step 514.1 , increasing the active power proportionally when line-side frequency increases and vice-versa; and
Step 514.2, increasing the inductive reactive power proportionally as the line-side voltage increases, and increasing the capacitive reactive power proportionally as the line-side voltage decreases.
According to an embodiment of the present invention, the method allocates the active and reactive power increment to each charging unit based on the predefined criteria, e.g. allocating the active and reactive power increment proportionally to each charging unit base on its capacity margin; or allocating the active and reactive power increment to each charging unit based on its priority and its capacity margin.
An embodiment of the present invention provides a hierarchical active and reactive power control method in electric vehicle charging stations. The local controller is configured to balance the less and more frequent deviation about the frequency and/or voltage. Such deviation is caused by near-by charging units, charging stations or other loads. The central controller is configured to utilize the available capacities of all charging units so as to regulation the power grid frequency and voltage supply.
Besides the EV charging station, the proposed solutions can be further applied to other controllable equipments in power systems. Fig.6 illustrates a possible application configuration of load-side hierarchical active and reactive power control system according to an embodiment of the present invention. As shown in Fig.6, the co-generators of industry power plants, large-scale industrial motors fed by Variable Frequency Drives (VFDs), and even some of the household appliances are feasible to realize active or reactive power regulation can all be integrated into such control system. As analyzed above, both power grid and the equipment owners will benefit from the proposed solutions.
The proposed embodiments of the present invention provide the hierarchical active and reactive power control system and methods thereof. Adopt the spirit of the innovation, the Power grid, EV charging stations and EV owners can all benefit from the proposed solutions. For power grid, the dispersed energy storage devices can be fully utilized for primary/secondary frequency regulation; the embed power factor control capability of four-quadrant battery charging units can be further adopted to provide reactive power compensation and dynamic voltage support; furthermore, large-scale EV charging station can even contribute for peak shaving, grid stability enhancement and possibly proliferation of intermittent renewable energy generation integration.
For EV charging stations, they can get additional economic benefits from utilities by providing such ancillary active/reactive power support services, so as to reduce the payback time of their investments for EV charging infrastructures.
For EV owners, if they accept such Vehicle to Grid concept and join such control system, they can choose to sell electricity back to grid during peak hours so as to obtain additional revenue stream.
Though the present invention has been described on the basis of some preferred embodiments, those skilled in the art should appreciate that those embodiments should by no means limit the scope of the present invention. Without departing from the spirit and concept of the present invention, any variations and modifications to the embodiments should be within the apprehension of those with ordinary knowledge and skills in the art, and therefore fall in the scope of the present invention which is defined by the accompanied claims.

Claims

1 . A hierarchical active and reactive power control system in electric vehicle charging stations comprising a plurality of charging units, characterized in that said system further comprises:
a central controller configured to calculate the corresponding capacity margin of each charging unit based on the active and reactive power of each charging unit, calculate the active and reactive power increment of each charging unit based on the external dispatch command and the calculated capacity margin, and send said increment to each local controller; and
a local controller in each charging unit, configured to measure the active and reactive power of the relevant charging units and send the measuring results to the central controller, measure the line-side frequency and voltage, and adjust the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage as well as the increment from the central controller.
2. The system according to claim 1 , characterized in that said central controller comprises:
a communication unit configured to receive the external dispatch command and communicate with local controllers;
a calculating unit configured to calculate the capacity margin of each charging unit and the active and reactive power increment of each charging unit.
3. The system according to claim 1 , characterized in that each said local controller comprises:
a measuring unit configured to measure the active and reactive power of each charging unit and the line-side frequency and voltage;
a communication unit configured to send the active and reactive power of each charging unit to the central controller and receiving the active and reactive power increment;
an adjusting unit configured to regulate the active and reactive power of each charging unit based on the measurement of line-side frequency and voltage and the increment from the central controller.
4. The system according to claim 1 , characterized in that said local controller is configured to balance less and more frequent deviation about the frequency and/or voltage.
5. The system according to claim 4, characterized in that said deviation is caused by near-by charging units, the charging stations or the other loads.
6. The system according to claim 1 , characterized in that said central controller is configured to utilize the available capacities of all charging units so as to regulate the power grid frequency and the voltage supply.
7. The system according to claim 1 , characterized in that said system comprises a plurality of local controllers.
8. The system according to claim 1 , characterized in that said system comprises no less than one central controller.
9. A hierarchical active and reactive power control method in electric vehicle charging stations, characterized in that said method comprises:
measuring, by the local controller, the active and reactive power of the relevant charging units; and sending the measuring results to the central controller;
measuring, by the local controller, the line-side frequency and voltage; calculating, by the central controller, the corresponding capacity margin of each charging unit based on the active and reactive power of each charging units; and calculating the active and reactive power increment of each charging unit based on the external dispatch command and the calculated capacity margin;
sending the increment to each local controller; and
adjusting, by the local controller, the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage and the increment from the central controller.
10. The method according to claim 9, characterized in that said adjusting the active and reactive power of each charging unit based on the measurement of the line-side frequency and voltage comprising the following steps:
increasing the active power proportionally when frequency increases and vice-versa;
increasing the inductive reactive power proportionally when voltage increases, and increasing the capacitive reactive power proportionally when voltage decreases.
11 . The method according to claim 9 or 10, characterized in that said method further comprises allocating the active and reactive power increment proportionally to each charging unit based on its capacity margin.
12. The method according to claim 9 or 10, characterized in that said method further comprises allocating the active and reactive power increment to each charging unit based on its priority and its capacity margin.
13. The method according to claim 9 or 10, characterized in that said local controller is configured to balance the less and more frequent deviation about the frequency and/or voltage.
14. The method according to claim 9 or 10, characterized in that said deviation is caused by near-by charging units, the charging stations or the other loads.
15. The method according to claim 9 or 10, characterized in that said central controller is configured to utilize the available capacities of all charging units so as to regulate the power grid frequency and the voltage supply.
PCT/CN2011/071567 2011-03-07 2011-03-07 Hierarchical active and reactive power control system in electric vehicle charging stations and method thereof WO2012119300A1 (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130110304A1 (en) * 2010-04-12 2013-05-02 Hitachi, Ltd. Electric-power management system, electric-power management method, and section controller
DE102014005089A1 (en) * 2014-04-08 2015-10-08 Rwe Deutschland Ag Method and device for detecting an electrical variable of an electrical distribution network
WO2015196193A1 (en) * 2014-06-20 2015-12-23 General Electric Company System and method of power control for an energy storage charging station
WO2016015281A1 (en) * 2014-07-31 2016-02-04 Abb Technology Ltd System for charging battery of electric vehicle
EP3213388A4 (en) * 2014-10-31 2017-11-22 ABB Schweiz AG Control system for electric vehicle charging station and method thereof
WO2018193097A1 (en) * 2017-04-21 2018-10-25 Wobben Properties Gmbh Charging station for charging multiple electric vehicles, in particular electric cars
DE102019121848A1 (en) * 2019-08-14 2021-02-18 Wobben Properties Gmbh Method for operating a charging station for electric vehicles
CN113131514A (en) * 2021-03-31 2021-07-16 国电南瑞科技股份有限公司 Multi-source active control method and system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1877952A (en) * 2005-06-10 2006-12-13 北京机电研究所 Electric automobile charging station
CN201374569Y (en) * 2008-12-09 2009-12-30 剩沅科技股份有限公司 Charging station
CN101882802A (en) * 2010-05-18 2010-11-10 浙江工业大学 Distributed flywheel energy storage electric vehicle charging station
KR20100130452A (en) * 2009-06-03 2010-12-13 한전케이디엔주식회사 Charging station management system for an electric vehicle with load sharing algorithm

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1877952A (en) * 2005-06-10 2006-12-13 北京机电研究所 Electric automobile charging station
CN201374569Y (en) * 2008-12-09 2009-12-30 剩沅科技股份有限公司 Charging station
KR20100130452A (en) * 2009-06-03 2010-12-13 한전케이디엔주식회사 Charging station management system for an electric vehicle with load sharing algorithm
CN101882802A (en) * 2010-05-18 2010-11-10 浙江工业大学 Distributed flywheel energy storage electric vehicle charging station

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
YAN, HUI ET AL.: "Development of Supervisory Control System for Electric Vehicle Charging Station.", POWER SYSTEM TECHNOLOGY, vol. 33, no. 12, June 2009 (2009-06-01), pages 15 - 19 *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9395741B2 (en) * 2010-04-12 2016-07-19 Hitachi, Ltd. Electric-power management system, electric-power management method, and section controller
US20130110304A1 (en) * 2010-04-12 2013-05-02 Hitachi, Ltd. Electric-power management system, electric-power management method, and section controller
DE102014005089A1 (en) * 2014-04-08 2015-10-08 Rwe Deutschland Ag Method and device for detecting an electrical variable of an electrical distribution network
CN106660461B (en) * 2014-06-20 2019-08-02 通用电气公司 The system and method for power control for energy stores charging station
US10520966B2 (en) 2014-06-20 2019-12-31 General Electric Company System and method of power control for an energy storage charging station
CN106660461A (en) * 2014-06-20 2017-05-10 通用电气公司 System and method of power control for an energy storage charging station
US20170155253A1 (en) 2014-06-20 2017-06-01 General Electric Company System and method of power control for an energy storage charging station
JP2017518725A (en) * 2014-06-20 2017-07-06 ゼネラル・エレクトリック・カンパニイ Power control system and method for energy storage and charging station
WO2015196193A1 (en) * 2014-06-20 2015-12-23 General Electric Company System and method of power control for an energy storage charging station
US10179515B2 (en) 2014-07-31 2019-01-15 Abb Schweiz Ag System for charging battery of electric vehicle including a controller connected to at least one switch
WO2016015281A1 (en) * 2014-07-31 2016-02-04 Abb Technology Ltd System for charging battery of electric vehicle
US10137796B2 (en) 2014-10-31 2018-11-27 Abb Schweiz Ag Control system for electric vehicle charging station and method thereof
EP3213388A4 (en) * 2014-10-31 2017-11-22 ABB Schweiz AG Control system for electric vehicle charging station and method thereof
WO2018193097A1 (en) * 2017-04-21 2018-10-25 Wobben Properties Gmbh Charging station for charging multiple electric vehicles, in particular electric cars
US11192465B2 (en) 2017-04-21 2021-12-07 Wobben Properties Gmbh Charging station for charging multiple electric vehicles, in particular electric cars
DE102019121848A1 (en) * 2019-08-14 2021-02-18 Wobben Properties Gmbh Method for operating a charging station for electric vehicles
CN113131514A (en) * 2021-03-31 2021-07-16 国电南瑞科技股份有限公司 Multi-source active control method and system

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