SE2251298A1 - Frequency regulation of grid - Google Patents

Abstract

A method of frequency regulation support of an electrically coupled power grid (110), the method comprising measuring a frequency (f-meas) of alternating current, AC, power provided by the coupled power grid (110), controlling charging or discharging behavior of an electric vehicle (130) electrically coupled to the unit (120), using the measured frequency (f-meas), by sending a control signal, wherein the signal is indicative of at least one command to control the electric vehicle (130) to receive a charging current from the unit (120, 320, 700) if the measured frequency (f-meas) is above a first threshold value (FTH1), or at least one command to control the electric vehicle (130) provide a discharging current to the unit (120, 320, 700) if the measured frequency (f-meas) is below a second threshold value (FTH2).(Figure 1)

Description

TECHNICAL FIELD The present invention relates to method of local frequency regulation support of an electrically coupled power grid.

BACKGROUND Electrical generation in utility power grids is today moving away from large, centralized generation, and toward distributed systems with many distributed generators. This makes achieving frequency stability in the grid considerably more challenging.

Ancillary services to provide frequency stability are required, in particular, services that can handle the more dynamic behavior of distributed generators, such as solar and wind power generators. These type types of generators typically lack the characteristics of rotating inertia that traditional rotating generators provide.

Conventional solutions typically rely on communication with central nodes, e.g., as shown in document US8478452B2.However, they suffer from delays in response time when performing the regulation. ln fact, there is an inherent risk that a message from a central node to one or many distributed frequency stability servicing nodes never reaches its destination.

Thus, there is a need for an improved method for regulating frequency in a utility power grid.

OBJECTS OF THE INVENTION An objective of embodiments of the present invention is to provide a solution which mitigates or solves the drawbacks described above.

SUMMARY The above objective is achieved by the subject matter described herein. Further advantageous implementation forms of the invention are described herein.

According to a first aspect of the invention the object of the invention is achieved by a method of frequency regulation support of an electrically coup|ed power grid, the method comprising measuring a frequency of a|ternating current, AC, power provided by the coup|ed power grid , contro||ing charging or discharging behavior of an electric vehicle electrically coup|ed to the unit, using the measured frequency, by sending a control signal, wherein the signal is indicative of at least one command to control the electric vehicle to receive a charging current from the unit if the measured frequency is above a first threshold value, or at least one command to control the electric vehicle provide a discharging current to the unit if the measured frequency is below a second threshold value.

The advantage of this first aspect includes at least that activation/response time for frequency regulation is improved. A further advantage is that adaptation to local distributed power generation is facilitated.

According to a second aspect of the invention the object of the invention is achieved by a unit configured to provide local frequency regulation support of an electrically coup|ed power grid, the unit comprising a processor, and a memory, said memory containing instructions executable by said processor, wherein said control unit is configured to perform the method according to the first aspect.

According to a third aspect of the invention the object of the invention is achieved by a central control unit configured to provide local frequency regulation support of an electrically coup|ed power grid, the central control unit being coup|ed to the grid and one or more units according to the second aspect, the central control unit comprising a processor, and a memory, said memory containing instructions executable by said processor, wherein said control unit is configured to perform the method according to the first aspect.

According to a fourth aspect of the invention the object of the invention is achieved by an electric vehicle electrically coup|ed to the unit according to the second aspect, the vehicle comprising a processor, and a memory, said memory containing instructions 2 executable by said processor, wherein said control vehicle is configured to receive a control signal, wherein the signal is indicative of at least one command to control the electric vehicle to receive a charging current from the unit, or at least one command to control the electric vehicle provide a discharging current to the unit, wherein the electric vehicle is configured to receive a charging current or to provide a discharging current to the unit using the received control signal.

According to a fifth aspect of the invention a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to the first aspect.

According to a sixth aspect of the invention a computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method according to the first aspect.

The scope of the invention is defined by the claims, which are incorporated into this section by reference. Reference will be made to the appended sheets of drawings that will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates a vehicle to grid, V2G, scenario.

Fig. 2 shows a V2G scenario with multiple units according to one or more embodiments of the present disclosure.

Fig. 3 shows a V2G scenario with multiple units and a central control unit according to one or more embodiments of the present disclosure.

Fig. 4 illustrates a scenario where the measured frequency exceeds a first threshold value according to one or more embodiments of the present disclosure.

Fig. 5 illustrates a scenario where the measured frequency subceeds/is below a second threshold value according to one or more embodiments of the present disclosure.

Fig. 6 illustrates a flowchart of frequency regulation support of an electrically coupled power grid 110 according to one or more embodiments of the present disclosure.

Fig. 7 shows the unit according to one or more embodiments of the present disclosure. Fig. 8 illustrates a system for performing frequency regulation.

Fig. 9 shows how controlling charging or discharging behavior of an electric vehicle is performed dependent on time.

Fig. 10 shows how controlling charging or discharging behavior depends on a desired frequency regulation service according to one or more embodiments of the present disclosure.

A more complete understanding of embodiments of the invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. lt should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures.

DETAILED DESCRIPTION Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated othen/vise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

An "or" in this description and the corresponding claims is to be understood as a mathematical OR which covers "and" and "or", and is not to be understand as an XOR (exclusive OR). The indefinite article "a" in this disclosure and claims is not limited to "one" and can also be understood as "one or more", i.e., plural. ln the present disclosure the term "frequency regulation" denotes balancing of electricity power supply and demand (load) over a defined time frame. Examples of frequency regulation services are Fast Frequency Reserve, FFR, Automatic Frequency Restoration Reserve, aFRR, Balancing energy and balancing capacity markets, mFRR, Frequency Containment Reserve - Normal, FCR-N, Frequency Containment Reserve - Disturbance, FCR-D. ln the present disclosure the term "grid" or "power grid" denotes a network of synchronized power generators and consumers/loads that are connected by electrical transmission and distribution lines. The grid may be a local grid/micro-grid or a national grid.

The present disclosure relates to frequency regulation of an electrically coupled power grid. ln particular, providing frequency regulation support of an electrically coupled power grid performed by a unit, such as electric vehicle supply equipment, EVSE or a central control unit coordinating charging/discharging of a plurality of vehicles each electrically coupled to a respective unit/EVSE.

The grid supplying electrical energy to the unit and/or central control unit is part of a system for performing frequency regulation. Such a system is further described in relation to Fig. 8. The local grid supplying the electrical energy is operated by a Distribution System Operator or DSO.

Each of the plurality of vehicles typically have an operator/owner/driver with the authority to decide over the right to control charging/discharging of the vehicle and how and to which extent the battery in the vehicle can be used.

A plurality of units and/or central control units may have an operator/entity called Electric Vehicle Aggregator or EVA.

The present disclosure requires that there are at least arrangements/contracts between the DSO and the EVA, and the EVA and the vehicle operators/owners/drivers.

The EVA may e.g., commit to the DSO to provide a desired frequency regulation service.

The vehicle operators/owners/drivers may e.g., commit to the EVA that the respective vehicle and the battery/energy storage therein may be used for frequency regulation of the coup|ed grid and to which extent/how much of the total capacity of the battery that may be used for the purpose of frequency regulation of the coup|ed grid. Further, the vehicle operators/owners/drivers may e.g., commit to the EVA a maximum effect that can be received or provided to the grid, E.g., 11 kW and 5-10% of the maximum battery capacity.

The arrangements/contracts between the DSO and the EVA, and the EVA and the vehicle operators/owners/drivers may e.g., be performed by digitally signing consent in an application, e.g., in a general-purpose computer or a smartphone.

The unit and/or the central unit then monitors the frequency of the coup|ed alternating current, AC, provided by the utility grid Fig. 1 illustrates a vehicle to grid, V2G, scenario. A utility electrical grid 110 is electrically coup|ed to a unit 120, e.g., electrical vehicle supply equipment, EVSE, and is configured to provide to or receive from the unit 120 alternating current, AC. Power.

The AC power provided by the grid 110 has a frequency f (not shown) and varies with the load of the grid 110. The grid 110 has a nominal frequency reference that is maintained over time. When the grid 110 generates more power than what is required by the electrically connected loads, the frequencyftypically increases from the nominal frequency reference. When the grid 110 generates less power than what is required by the electrically connected loads, the frequency f typically decreases from the nominal reference. The nominal frequency reference may e.g., be 50 Hz or 60 Hz.

To correct these variations, additional equipment is connected to the grid 110. These are often of the type of rotational inertia units, such as heavy rotating generators. However, the response time is relatively slow, and the use of solar/wind power generate relatively quick variations in particular local areas, leading to frequent and unpredictable variation in the generated power.

The present disclosure aims to improve response time and support the grid 110 in a de-centralized manner. ln other words, the present disclosure attempts to support distributed frequency regulation of the coupled grid 110 by allowing one or more units to individually measure the frequency f of the grid 110 and make a distributed decision to alter its behavior to support the grid 110.

This has significant advantages when it comes to response time and adaptation to local distributed power generation, e.g., by solar or wind power.

The unit 120 is typically electrically coupled to a vehicle 130 and is configured to provide or control the provision of a charging current to the vehicle or receive or control reception of a discharging current from the vehicle 130.

The unit 120 may in embodiments be configured to receive AC power from the grid 110 and provide AC power to the vehicle 130. E.g., an AC/AC EVSE. Alternatively, unit may in embodiments be configured to receive AC power from the grid 110 and provide direct current, DC, power to the vehicle 130. E.g., an AC/DC EVSE.

The vehicle 130 may e.g., be an electric vehicle or a hybrid combustion/electrically powered vehicle.

The vehicle 130 typically have an operator/owner/driver with the authority to decide over the right to control charging/discharging of the vehicle and to which extent the battery in the vehicle can be used. The operator/owner/driver further typically have a user device 140, such as a smartphone, that can be used to provide user input indicating the right to control charging/discharging of the vehicle, a maximum effect that may be provided/received to the vehicle and to which extent the battery in the vehicle can be used. Typically, the operator/owner/driver may indicate that a maximum effect of 11 kW may be provided/received to the vehicle and that 5-10% of the battery capacity of the vehicle may be used for frequency regulation of the grid 110.The operator/owner/driver may further indicate a target State Of Charge, SoC, and a target time when the target SoC should be achieved in the vehicle.

The unit 120 may then use these indications to control charging/discharging of the vehicle 130 and ensure that the requirements of the operator/owner/driver is complied with.

Fig. 2 shows a V2G scenario with multiple units 120-124 according to one or more embodiments of the present disclosure. This could in one example be a commercial parking lot where multiple units 120-124 supply power to multiple vehicles 130-134.

As mentioned in relation to Fig. 1, each unit 120-124 makes a distributed decision on if power should be received from or provided to the grid 110.

Each unit 120-124 measures locally the frequency fof alternating current, AC, power provided by the coupled power grid 110. ln embodiments, the frequency f is measured at points in time using a unique random delay. ln other words, each unit 120-124 will measure the frequency f at slightly different points in time to avoid simultaneous control of the vehicles 130-134. ln other words, introducing the random delay mitigates toggling effects that could occur if a large number of vehicles are controlled simultaneously and are causing large addition or removal of load to the grid 110. This could be ensured by providing each unit 120-124 with a unique seed used in a respective random number generator. Alternatively, each unit 120-124 will measure the frequencyfat predetermined points in time and/or scheduled points in time to avoid simultaneous control of the vehicles 130-134. The predetermined points in time and/or schedule may be stored in a memory of each unit 120-124.

Another alternative to ensuring randomness would be to introduce a random delay before an action is taken, i.e., measuring is made constantly and when a decision to act has been made a random delay in time is needed to pass before the action is executed, e.g., an action of sending a control signal.

Each unit 120-124 then controls charging or discharging behavior of the respective electric vehicle 130-134 electrically coupled to the unit 120-124, using the measured frequency f by sending a control signal S1-S5 to the respective electric vehicle 130- 134. ln Fig. 2, the signal is indicated by the dotted arrow and the current flow by the solid GFFOW. lf the respective measured frequency f-meas is above a first threshold value FTH1 (not shown), the signal (S1-S5) is indicative of at least one command to control the electric vehicle 130-134 to receive a charging current from the unit 120-124. This will increase the load on the grid 110, and contribute to lower the grid frequency f. 8 lf the measured frequency f-meas is below a second threshold value FTH2 (not shown), the signal (S1-S5) is indicative of at least one command to control the electric vehicle 130-134 to provide a discharging current to the unit 120-124. This will reduce the load on the grid 110/increase the generation of power in the grid 110, and contribute to increase the grid frequency f. ln some embodiments, the control signal S1-S5 is sent using a unique random delay. ln other words, each unit 120-124 will control the respective vehicle 130-134 at slightly different times to avoid transferring interference, e.g., voltage transients or spikes, to the grid 110. Alternatively, each unit 120-124 will control the respective vehicle at predetermined points in time and/or at scheduled points in time to avoid simultaneous control of the vehicles 130-134. The predetermined points in time and/or schedule may be stored in a memory of each unit 120-124.

Fig. 3 shows a V2G scenario with multiple units 120-124 and a central control unit 320 according to one or more embodiments of the present disclosure. This could in one example be a residence parking lot where multiple units 120-124 supply power to multiple vehicles 130-134. The central control unit 320 may e.g., be responsible to distribute power between the multiple units 120-124 to ensure that the total power can be supported by the grid 110, e.g., not to exceed the maximum current supported by the fuse protecting the power supply from a local grid.

The central control unit 320 measures locally the frequency f of alternating current, AC, power provided by the coupled power grid 110. central control unit 320 then controls charging or discharging behavior of the respective electric vehicle 130-134 electrically coupled to the unit 120-124, using the measured frequency f by sending a control signal S1-S5 to the respective electric vehicle 130- 134 via the respective vehicle connection unit, e.g., an AV/AC EVSE or AC/DC EVSE.

The central control unit 320 may e.g., select a set or a subset of electric vehicle 130- 134 where the operator/owner/driver has given consent to use the respective vehicle if certain requirements are met. ln Fig. 2, the respective control signal (S1-S5) is indicated by the dotted arrow and the current flow by the solid arrow. lf the respective measured frequency is above a first threshold value FTH1 (not shown), the respective signal (S1-S5) is indicative of at least one command to control the respective electric vehicle 130-134 to receive a charging current from the unit 120- 124. This will increase the load on the grid 110, and contribute to lower the grid frequency f. lf the measured frequency is below a second threshold value FTH2 (not shown), the signal (S1 -S5) is indicative of at least one command to control the electric vehicle 130- 134 to provide a discharging current to the unit 120-124. This will reduce the load on the grid 110/increase the generation of power in the grid 110, and contribute to increase the grid frequency f. ln some embodiments, the control signal S1-S5 is each sent using a unique random delay. ln other words, the central control unit 320 will control the respective vehicle 130-134 at slightly different times to avoid transferring interference, e.g., voltage transients or spikes, to the grid 110. Alternatively, the central control unit 320 will control the respective vehicle at predetermined points in time and/or at scheduled points in time to avoid simultaneous control of the vehicles 130-134. The predetermined points in time and/or schedule may be stored in a memory of the central control unit 320.

Fig. 4 illustrates a scenario where the measured frequency f-meas exceeds a first threshold value FTH1 according to one or more embodiments of the present disclosure. This is illustrated by a measured AC power period time of t and a reference period time of T1, which can be converted to respective frequency values.

Fig. 4 illustrates in the top part a diagram of the grid voltage. As can be seen from the diagram the time of a period or between two zero crossings is measured to a time value t. The measured time t is shorter than a first time threshold T1. A measured frequency f-meas can then be determined as: f-meas=1/t The first frequency threshold FTH1 can optionally be determined as 1/T1. ln this example, the measured frequency f-meas is higher than the first frequency threshold FTH1.

Fig. 4 illustrates in the bottom part the behavior of the controlled vehicle 120. The controlled vehicle 120 receives a charging current from the unit 120 and/or the central control unit 320. This will increase the load on the grid 110, and contribute to lower the grid frequency f.

Fig. 5 illustrates a scenario where the measured frequency f-meas subceeds/is below a second threshold value FTH2 according to one or more embodiments of the present disclosure.

Fig. 5 illustrates in the top part a diagram of the grid voltage U. As can be seen from the diagram the time of a period or between two zero crossings is measured to a time value t. The measured time t is longer than a second time threshold T2. A measured frequency f-meas can then be determined as: f-meas=1/t The second frequency threshold FTH2 can optionally be determined as 1/T2. ln this example, the measured frequency f-meas is lower than/subceeds the second frequency threshold FTH2.

Fig. 5 illustrates in the bottom part the behavior of the controlled vehicle 120. The controlled vehicle 120 provides a discharging current from the controlled vehicle 130 to the unit 120 and/or the central control unit 320. This will reduce the load on the grid 110, and contribute to increase the grid frequency f.

Fig. 6 illustrates a flowchart of frequency regulation support of an electrically coupled power grid 110 according to one or more embodiments of the present disclosure. ln embodiments, the method is performed by a unit 120, a central control unit 320 or a combination of both the unit 120 and the central control unit 320.

Step 610: measuring a frequency f-meas of alternating current power provided by the coupled power grid 110. As mentioned above, the utility grid provides AC power with a frequency f varying over time around the nominal frequency reference. The measured frequency f-meas may in embodiments be determined using a time of a period or between two zero crossings of the grid voltage is measured to a time value t. One example includes zero-crossing measurement techniques conforming to the IEC 61000-4-30:2015 standard. 11 ln one embodiment, measuring the frequency f-meas of alternating current power provided by the coupled power grid 110 is performed at a point in time dependent on a random delay. This has the advantage of mitigating toggling effects that could occur if a large number of vehicles are controlled simultaneously and are causing large addition or removal of load to the grid 110, e.g., causing voltage transients/spikes and/or interference to the grid 110.

The measured frequency f-meas is analyzed to determine if the measured frequency f-meas is above a first threshold value FTH1, or the measured frequency f-meas is below a second threshold value FTH2. lf the measured frequency f-meas is determined to be above a first threshold value FTH1, the method performs: Step 620(i): controlling charging or discharging behavior of the electric vehicle/s 130- 134 electrically coupled to the (respective) unit 120-124, 320 using the measured frequency f-meas by sending a control signal S1 -S5, wherein the signal/s S1 -S5 is/are indicative of at least one command to control the electric vehicle/s 120-124 to receive a charging current from the (respective) unit 120-124 if the measured frequency-meas is above the first threshold value FTH1. ln one embodiment, the measured frequency f-meas is aggregated using a statistical measure to an aggregated frequency, wherein the aggregated frequency is then compared below to the first threshold value FTH1 and the second threshold value FTH2, respectively. This has the effect of providing a measured frequency value of higher quality by removing transient effects and interference. ln one example, a plurality of frequency measurements is performed over time and an average is calculated as the aggregated frequency using the plurality of frequency meaSUfementS. ln one embodiment, the statistical measure is selected from an arithmetic mean, a median, a mode, a geometric mean, a harmonic mean, a quadratic mean, a cubic mean, or a weighted mean.

Alternatively, if the analysis shows that the measured frequency f-meas is below a second threshold value FTH2, the method performs: 12 Step 620(ii): controlling charging or discharging behavior of an electric vehicle electrically coupled to the (respective) unit 120-124, 320 using the measured frequency f-meas by sending a control signal/s S1-S5, wherein the signal/s S1-S5 is/are indicative of at least one command to control the electric vehicle 130-134 to provide a discharging current to the (respective) unit 120-124, 320 if the measured frequency f- meas is below the second threshold value FTH2. lf the measured frequency f-meas is determined to be between the first threshold value FTH1 and the second threshold value FTH2, the method repeats step 610 of measuring the frequency f-meas of alternating current power provided by the coupled power grid. ln one embodiment, the control signal is sent using a random delay.

Additionally, or alternatively, the control signal is sent only if a first parameter indicates that the electric vehicle 130 is enabled to provide frequency regulation support of an electrically coupled power grid 110. ln one example, the owner of the vehicle indicates in his app/application that he agrees to allow the owner's electric vehicle 130 to be used to provide frequency regulation support. This approval is then saved as the first parameter in a central database and/or in the unit/s 120.

Additionally, or alternatively, the control signal is sent only if a second parameter indicates that a state of charge, SoC, of a battery electric vehicle 130, is within a predetermined range. ln one example, the owner of the vehicle indicates in his app/application that he agrees to allow the owner's electric vehicle 130 to be used to provide frequency regulation support only of the SoC is within a predetermined range, e.g., 40-60%.

Additionally, or alternatively, the predetermined range comprises a SoC of 75-95% or 85-100% or 90-95%.

Additionally, or alternatively, the control signal is sent only if a third parameter indicates how much of the electric vehicle's battery capacity that is allowed to use to be used to provide frequency regulation support. 13 ln one example, the owner of the vehicle indicates in his app/application how much of the electric vehicle's battery capacity that is allowed to use to be used to provide frequency regulation support, e.g., 5-10% of the total battery capacity. This indication is then saved as the third parameter in a central database and/or in the unit/s 120.

Additionally, or alternatively, the control signal is sent only if a fourth parameter indicates a minimum value of SoC that is required to provide frequency regulation support. ln one example, the owner of the vehicle may indicate a minimum value of SoC that is required to provide frequency regulation support. This indication is then saved as the fourth parameter in a central database and/or in the unit/s 120.

Additionally, or alternatively, the control signal is sent only if a fifth parameter indicates maximum power that may be used to provide frequency regulation support. ln one example, the owner of the vehicle may indicate a maximum power that may be used to provide frequency regulation support. This indication is then saved as a fifth parameter in a central database and/or in the unit/s 120. ln one example, a matrix of parameters is provided. The matrix of parameters indicates e.g., F-low, F-high, maximum power kW, duration of frequency regulation (minutes).

An example of a matrix is further described in Fig. 9. ln one example, messages are sent to an aggregator server that are indicative of charging/discharging currents received/provided, or the power that is received from or provided to the grid 110. ln one example, pre-heating or cooling of the batteries are initiated after a request to regulate the frequency. ln one embodiment, the unit 120 comprises an EVSE providing alternating current, AC, or an EVSE providing direct current, DC. ln one embodiment, the central control unit 320 comprises a grid controller.

As mentioned above, the functionality of the method may be distributed between the unit 120 and the central control unit 320 without departing from the present disclosure. 14 ln one example, the unit 120 performs the frequency measurement of the grid and sends the control signal S1-S5 to the coupled vehicle. ln one further example, the unit 120 performs the frequency measurement of the grid and sends a control message to the central control unit 320. The central control unit 320 then sends the control signal S1-S5 to coupled vehicles. ln one further example, the central control unit 320 performs the frequency measurement of the grid. The central control unit 320 then sends the control signal S1 - S5 to vehicles 120-124 via the units 120-124.

Fig. 7 shows the unit 700 according to one or more embodiments of the present disclosure. The battery charger 700 may be in the form of e.g., a central control unit 320, an EVSE, a battery charger, an Electronic Control unit, a server, an on-board computer, a stationary computing device, a laptop computer, a tablet computer, a handheld computer, a wrist-worn computer, a smart watch, a smartphone or a smart TV. The battery charger 700 may comprise a processor/processing circuitry 712, optionally communicatively coupled to a communications interface 704, e.g., a transceiver configured for wired or wireless communication. ln one example, the processing circuitry 712 may be any of a selection of processing circuitry and/or a central processing unit and/or processor modules and/or multiple processors configured to cooperate with each-other.

Further, the unit 700 may further comprise a memory 715. The memory 715 may e.g., comprise a selection of a hard RAM, disk drive, a floppy disk drive, a flash drive or other removable or fixed media drive or any other suitable memory known in the art. The memory 715 may contain instructions executable by the processing circuitry to perform any of the steps or methods described herein.

The processing circuitry 712 may optionally be communicatively coupled to a selection of any of the communications interface 704, the memory 715, one or more sensors, such as battery/charging voltage sensors measuring battery/charging voltage over poles of the battery. The battery charger 700 may be configured to send/receive control signals directly to any of the above-mentioned units or to external nodes. E.g., to send control signals S1-S5 over electrical coupling means, such as a charging cable, to a vehicle 130.

The communications interface 704, such as a wired network adapter and/or a wired, may be configured to send and/or receive data values or parameters as a signal to or from the processing circuitry 712 to or from other external nodes. E.g., measured battery/charging voltage values. ln an embodiment, the communications interface 804 communicates directly to external nodes. ln one or more embodiments the unit 700 may further comprise an input device 717, configured to receive input or indications from a user and send a user input signal indicative of the user input or indications to the processing circuitry 712. ln one or more embodiments the unit 700 may further comprise a display 718 configured to receive a display signal indicative of rendered objects, such as text or graphical user input objects, from the processing circuitry 712 and to display the received signal as objects, such as text or graphical user input objects. ln one embodiment the display 718 is integrated with the user input device 717 and is configured to receive a display signal indicative of rendered objects, such as text or graphical user input objects, from the processing circuitry 712 and to display the received signal as objects, such as text or graphical user input objects, and/or configured to receive input or indications from a user and send a user-input signal indicative of the user input or indications to the processing circuitry 712. ln a further embodiment, the battery charger 700 may further comprise and/or be coupled to one or more additional sensors (not shown in the figure) configured to receive and/or obtain and/or measure physical properties pertaining to the unit 700, the central control unit 320 or the grid 110, and send one or more sensor signals indicative of the physical properties of the unit 700 or the coupled grid 110 to the processing circuitry 712. E.g., an external voltage sensor measuring power grid voltage/frequency/current and/or ambient temperature. ln one or more embodiments, the unit 700 further comprises a controllable power exchange unit 719 configured to be electrically coupled to the vehicle 130, e.g., via a charging cable. The controllable power exchange unit 719 may be configured to provide AC and/or DC power having particular characteristics in response to a control signal received from the processing circuitry 712. The controllable power exchange 16 unit 719 may further be configured to receive AC and/or DC power having particular characteristics from the electrically coupled vehicle 130-134. ln one or more embodiments, the processing circuitry 712 is further communicatively coupled to the communications interface 704 and/or the input device 717 and/or the display 718 and/or the controllable power exchange unit 719 and/or the sensors and/or the additional sensors and/or any of the units described herein. ln one embodiment, a unit/EVSE 700 is provided, the battery charger 700 comprising a processor 712, and a memory 715, said memory containing instructions executable by said processor, whereby said EVSE 700 is operative and/ or configured to perform any of the method steps described herein.

Moreover, it is realized by the skilled person that the unit/EVSE 700 may comprise the necessary communication capabilities in the form of e.g., functions, means, units, elements, etc., for performing the present solution. Examples of other such means, units, elements and functions are: processors, memory, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selecting units, switches, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiver units, transmitter units, DSPs, MSDs, TCM encoder, TCM decoder, power supply units, power feeders, communication interfaces, communication protocols, etc. which are suitably arranged together for performing the present solution.

Especially, the processing circuitry and/or processing means of the present disclosure may comprise one or more instances of processing circuitry, processor modules and multiple processors configured to cooperate with each-other, Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, a Field-Programmable Gate Array (FPGA) or other processing logic that may interpret and execute instructions. The expression "processing circuitry" and/or "processing means" may thus represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above. The processing means may further perform data processing functions for inputting, outputting, and processing of data comprising data buffering and device control functions, such as user interface control, or the like. 17 ln one embodiment, a unit 120, 320, 700 is provided and is configured to provide local frequency regulation support of an electrically coupled power grid 110. The unit comprises a processor, and a memory, said memory containing instructions executable by said processor, wherein said control unit is configured to perform the method described herein. ln one embodiment, the unit 700 comprises a grid controller, an EVSE providing alternating current, AC, or an EVSE providing direct current, DC. ln one embodiment, an electric vehicle 130 is provided and is electrically coupled to the unit 120, the vehicle comprises a processor, and a memory, said memory containing instructions executable by said processor, wherein said control vehicle is configured to receive a control signal, wherein the signal is indicative of at least one command to control the electric vehicle 130 to receive a charging current from the unit 120, 320, 700, or at least one command to control the electric vehicle 130 provide a discharging current to the unit 120, 320, 700, wherein the electric vehicle 130 is configured to receive a charging current or to provide a discharging current to the unit 120, 320, 700 using the received control signal.

Additionally, or alternatively, the electric vehicle 130 is configured to receive a charging current or to provide a discharging current to the unit 120, 320, 700 only if a first parameter indicates that the electric vehicle 130 is enabled to provide frequency regulation support of an electrically coupled power grid 110.

Additionally, or alternatively, the electric vehicle 130 is configured to receive a charging current or to provide a discharging current to the unit 120, 320, 700 only if a second parameter indicates that a state of charge, SoC, of a battery electric vehicle 130, is within a predetermined range.

Additionally, or alternatively, the predetermined range comprises a SoC of 80-100%, more preferably a SoC of 90-100% and most preferably a SoC of 95-100%. ln one embodiment, a computer program product is provided and comprises instructions which, when the program is executed by a computer, cause the computer to carry out the methods described herein. 18 ln one embodiment, a computer-readable storage medium is provided and comprises instructions which, when executed by a computer, cause the computer to carry out the methods described herein.

Fig. 8 illustrates a system for performing frequency regulation. The vehicles 130 are coup|ed to respective units 120, and the units/EVSE are electrically coup|ed to the grid 110. A Distribution System Operator, DSO; is responsible for distributing and managing energy from the generation sources to the final consumers. An EV aggregator manages the charging of an EV fleet. lt is typically an Electric Vehicle aggregator, EVA, or charging station manager, or a company fleet manager is responsible for optimizing and coordinating charging of a plurality of vehicles. A Transmission System Operator, TSO, is entrusted with transporting energy on a national or regional level, using fixed infrastructure. Frequency regulation markets or electricity markets, MKTS, offers electric or regulation capacity. ln one example, the DSO is communicatively coup|ed to the units 120 via an IEC 61850-90-8 communication link. The EVA is communicatively coup|ed to the units 120 via an Open Charge Point Protocol, OCPP, communication link. The unit and/or central control unit 320 may then measure frequency of the grid and optionally send a message to the DSO and/or EVA.

Fig. 9 shows how controlling charging or discharging behavior of an electric vehicle is performed dependent on time. Fig. 9 shows a table with five columns. The first column represents time interval, e.g., 00.00-00.59, 01.00-01.59 etc. The third and second and third column represents the first and second threshold values, respectively. The fourth column indicates a desired or maximum power that should be received or provided. The fifth column indicates the duration that the desired power that should be received or provided by a respective unit 120.

Using a current time value and the data, a first and second threshold value can be denved. ln one example, a scenario shown in Fig. 2 is using the method described herein. Data indicative of charging or discharging behavior dependent on time, e.g., a representation of the table in Fig. 9, is received by the one or more units 120-124 or is stored in the one or more units 120-124. Each of the one or more units 120-124 will 19 then perform the method described in Fig. 6. Using a current time mapped to the table indicated by the data, a first threshold value can be derived from the second column. E.g., a current time of 08:04 can be mapped to a second threshold value of 49.85 Hz in the second column. ln a similar manner a desired charging power/current of 3 kW can be derived from the fourth column, a first threshold value of 50.15 Hz can be derived from the third column and a desired duration of the charging of 5 minutes can be derived from the firth column. Each of the one or more units 120-124 will then use the first threshold value of 50.15 Hz to determine that 3Kw will be provided to the electric vehicle for a duration of 5 minutes. ln one further example, a scenario shown in Fig. 3 is using the method described herein. Data indicative of charging or discharging behavior dependent on time, e.g., a representation of the table in Fig. 9, is received by the central control unit 320 or is stored in the central control unit 320. The central control unit 320 will then perform the method described in Fig. 6. Using a current time mapped to the table indicated by the data, a first threshold value can be derived from the second column. E.g., a current time of 08:04 can be mapped to a second threshold value of 49.85 Hz in the second column. ln a similar manner a desired charging power/current of 3 kW can be derived from the fourth column, a first threshold value of 50.15 Hz can be derived from the third column and a desired duration of the charging of 5 minutes can be derived from the firth column. The central control unit 320 will then use the first threshold value of 50.15 Hz to determine that 3Kw and a corresponding charging current will be provided to the electric vehicle for duration of 5 minutes. ln one further example, a scenario shown in Fig. 3 is using the method described herein. Data indicative of charging or discharging behavior dependent on time, e.g., a representation of the table in Fig. 9, is received by the central control unit 320 or is stored in the central control unit 320. The central control unit 320 and the one or more units 120-124 will then each perform parts of the method described in Fig. 6. Using a current time mapped to the table indicated by the data, a first and second threshold value can be derived. E.g., a current time of 08:04 can be mapped to a second threshold value of 49.85 Hz. A measured value of the frequency of alternating current power provided by the coupled power grid is received by the central control unit 320 from the one or more units 120-124. The measured value of the frequency may e.g., be received once every second. The central control unit 320 then sends the control signal to control the electric vehicle to provide a discharging current or receive a charging current dependent on the received data.

Optionally, the central control unit 320 further receives information on the temperature of the battery in the electric vehicle 130-134, and if the temperature is below a minimum temperature threshold, a battery heating action is initiated. This may involve to slowly ramp up the charging current to allow the battery to heat up before a higher desired charging current is received.

Fig. 10 shows how controlling charging or discharging behavior depends on a desired frequency regulation service according to one or more embodiments of the present disclosure. Fig. 10 shows a table with a first column indicating a name of the service and a second column indicating characteristics/requirements of that service.

The Fast Frequency Reserve, FFR, is a frequency regulation service procured to handle low-inertia situations in the grid 110. lnertia means the ability of the kinetic energy stored in the rotating masses in the electricity system to resist changes in grid frequency. The operation of the grid follows a dimensioning principle according to which e.g., the loss of a single electricity production unit or a HVDC link must not cause the frequency to fall below the second threshold. The magnitude of the transient frequency change following a disturbance depends on the magnitude of the power change caused by the disturbance, the system inertia, and the speed at which the reserves are activated. The required response time is 0.7 seconds at a network frequency of 49.5 Hz, 1.0 second at a network frequency of 49.6 Hz and 1.3 seconds at a network frequency of 49.7. ln other words, a quicker response is required when there is a larger frequency deviation from the nominal grid frequency.

Automatic Frequency Restoration Reserve, aFRR is a centralized automatically activated frequency regulation service. lt activates based on an activation request signal sent by the TSO, e.g., to the central control unit 320 and/or the one or more units 120-124. The minimum capacity of regulation is 1 MW and full activation time is 5 minutes maximum. Preferably activation time is 100% within 120 seconds. 21 Balancing energy and balancing capacity markets, mFRR, frequency regulation service is using an energy market for transmission system operators. Activation of 63% of desired power must be provided within 15 minutes.

Frequency Containment Reserve - Normal, FCR-N, is a frequency regulation service used at normal grid status. Activation of 63% of desired power must be provided within 60 seconds and 100% within 180 seconds.

Frequency Containment Reserve - Disturbance, FCR-D, is a frequency regulation service used at disturbed grid status. Activation of 50% of desired power must be provided within 5 seconds and 100% within 30 seconds. ln one further example, a scenario shown in Fig. 3 is using the method described herein. Data indicative of charging or discharging behavior dependent on a desired frequency regulation service, e.g., a representation of the table in Fig. 10, is received by the central control unit 320 or is stored in the central control unit 320. The central control unit 320 will then perform the method described in Fig. 6. A desired number of coupled electric vehicles will typically be selected and controlled to meet the characteristics/requirements of the desired frequency regulation service such as required activation time. An advantage of the present disclosure is that activation can be made with a relatively small delay, contrary to inertia-based frequency regulation methods.

Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims (20)

1. A method of frequency regulation support ofan electrically coupled power grid (110), the method comprising: measuring a frequency (f-meas) of alternating current, AC, power provided by the 5 coupled power grid (110), contro||ing charging or discharging behavior of an electric vehicle (130) electrically coupled to the unit (120), using the measured frequency (f-meas), by sending a control signal, wherein the signal is indicative of: at least one command to control the electric vehicle (130) to receive a 10 charging current from the unit (120, 320, 700) if the measured frequency (f-meas) is above a first threshold value (FTH1), or at least one command to control the electric vehicle (130) provide a discharging current to the unit (120, 320, 700) if the measured frequency (f-meas) is below a second threshold value (FTH2). 15 2. The method according to claim 1, wherein the frequency (f-meas) of the AC power is measured using a zero-crossing measurement technique conforming to the

2.IEC 61000-4-3022015 standard.

3. The method according to claim 1, further comprising aggregating the measured frequency (f-meas) using a statistical measure to an aggregated frequency, 20 wherein the aggregated frequency is compared to the first threshold value (FTH1) and the second threshold value (FTH2) respectively.

4. The method according to claim 3, wherein the statistical measure is selected from an arithmetic mean, a median, a mode, a geometric mean, a harmonic mean, a quadratic mean, a cubic mean or a weighted mean. 25

5. The method according to any of the preceding claims, wherein the control signal is sent using a random delay.

6. The method according to any of the preceding claims, wherein the unit comprises a grid controller, an EVSE providing alternating current, AC, or an EVSE providing direct current, DC.

7. The method according to any of the preceding claims, wherein the control signal is sent only if a first parameter indicates that the electric vehicle (130) is enabled to provide frequency regulation support of an electrically coupled power grid (110).

8. The method according to any of the preceding claims, wherein the control signal is sent only if a second parameter indicates that a state of charge, SoC, of a battery electric vehicle (130), is within a predetermined range.

9. The method according to claim 8, wherein the predetermined range comprises a SoC of 75-95% or 85-95% or 90-95%.

10. The method according to any of the preceding claims, wherein the control signal is sent only if a third parameter indicates that a current time is within one or more predetermined ranges.

11. The method according to claim 10, wherein the control signal is indicative is of a duration.

12. A unit (120) configured to provide local frequency regulation support of an electrically coupled power grid (110), the unit comprising: a processor, and a memory, said memory containing instructions executable by said processor, wherein said control unit is configured to perform the method according to any of claims 1-

13. The unit according to claim 12, wherein the unit (700) comprises an EVSE providing alternating current, AC, or an EVSE providing direct current, DC.

14. A central control unit (320) configured to provide local frequency regulation support of an electrically coupled power grid (110), the central control unit (320) being 5 coupled to the grid (110) and one or more units (120) according to claim 12, the central control unit (320) comprising: a processor, and a memory, said memory containing instructions executable by said processor, wherein said control unit is configured to perform the method according to any 10 ofclaims 1-

15. An electric vehicle (130) electrically coupled to the unit (120) according to any of claims 12-13, the vehicle comprising: a processor, and a memory, said memory containing instructions executable by said processor, 15 wherein said control vehicle is configured to: receive a control signal, wherein the signal is indicative of: at least one command to control the electric vehicle (130) to receive a charging current from the unit (120, 320, 700), or at least one command to control the electric vehicle (130) provide a 20 discharging current to the unit (120, 320, 700), wherein the electric vehicle (130) is configured to receive a charging current or to provide a discharging current to the unit (120, 320, 700) using the received control signal.

16. The electric vehicle (130) according to claim 15, wherein the electric vehicle (130) 25 is configured to receive a charging current or to provide a discharging current to the unit (120, 320, 700) only if a first parameter indicates that the electric vehicle (130) is enabled to provide frequency regulation support of an electrically coupled power grid (110).

17. The electric vehicle (130) according to any of the preceding claims, wherein the electric vehicle (130) is configured to receive a charging current or to provide a 5 discharging current to the unit (120, 320, 700) only if a second parameter indicates that a state of charge, SoC, of a battery electric vehicle (130), is within a predetermined range.

18. The electric vehicle (130) according to claim 17, wherein the predetermined range comprises a SoC of the predetermined range comprises a SoC of 75-95% or 10 85-100% Or 90-95%.

19. A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any of claims 1-

20. A computer-readable storage medium comprising instructions which, when 15 executed by a computer, cause the computer to carry out the steps of the method according to any of claims 1- 26