DE102019121387A1 - PROCEDURE AND UNIT FOR REDUCING A POWER REFERENCE DIFFERENCE - Google Patents

Abstract

A method for reducing a difference in power consumption during the charging process of an energy store of one or more vehicles, the vehicles being connected to one or more charging points of a charging device with multiple phases, comprising: determining phase-specific power consumption of the charging device; andreducing at least one difference in power consumption between the phase-specific power purchases by applying at least one equalizing load to at least one phase.

Description

Field of invention

The invention relates to a method for reducing a difference in power consumption during the charging process of an energy store in one or more vehicles and a unit for reducing a difference in power consumption.

Background of the invention

When charging single-phase electric vehicles (BEV's (Battery Electric Vehicle) and PHEV's (Plugin Hybrid Electric Vehicle)), for example, the phases in three-phase networks are usually loaded asymmetrically.

From the point of view of network operation, upper limits for the asymmetry of the phase load, the so-called phase imbalance or phase asymmetry, are defined in regulations, for example in connection conditions for systems on the low-voltage power grid, in order to ensure trouble-free network operation. The phase unbalance is limited, for example to a maximum of 3.7 kVA for a system behind a customer connection point (meter). The phase unbalance is defined as the greatest difference in power consumption between two phases (phase difference) of a multi-phase network. For example, three-phase networks are known.

But even in large charging facilities that are supplied by their own medium-voltage transformers, phase asymmetries must be kept within defined limits in order to be able to operate the transformers and associated systems within their specification limits.

Furthermore, a single-phase charging vehicle with a charging power above the applicable limit can exceed a specified limit for the unbalanced phase load. But especially in a charging situation with several vehicles, the limit for the phase unbalance can be exceeded: The vehicles randomly choose parking spaces with associated charging stations and their individual assignment to the connections of the phases of a three-phase supply network. This results in a random load situation on the individual phases with a possible exceeding of the unbalanced load limit, even if the charging capacity of the individual vehicle remains below the limit. For example, three single-phase vehicles with 3.7 kW charging power on phase result L1 and only one vehicle on each phase L2 and L3 an unbalanced load of 7.4 kW.

1. a) Phasendreh-Einrichtungen, die in Abhängigkeit der Phasenauslastung die Zuordnung der Ladephasen auf die Anschlussphasen mit Hilfe zusätzlicher Hardware-Umfänge wie Schütze oder Leistungselektronik erforderlichenfalls verändern können, und
2. b) lastbegrenzende Eingriffe auf die einzelnen Ladeprozesse, so dass die Schieflastgrenzen im Gesamtsystem eingehalten werden.

Well-known solutions for these problems are:

1. a) phase rotation devices that, depending on the phase load, can change the assignment of the charging phases to the connection phases with the help of additional hardware such as contactors or power electronics, and
2. b) Load-limiting interventions in the individual charging processes so that the unbalanced load limits in the overall system are observed.

1. a) Zusatzkosten in der Ladeinfrastruktur, da die Phasendreheinrichtung für jeden Ladepunkt vorhanden sein muss.
2. b) Verlängerung der Ladedauer einzelner Fahrzeuge bis hin zu der Situation, dass das Ladeziel des Nutzers in der verfügbaren Zeit bis zum Abstecken nicht mehr erreicht werden kann, das Fahrzeug also nicht ausreichend vollgeladen werden kann.

The following disadvantages result from these two approaches:

1. a) Additional costs in the charging infrastructure, as the phase rotation device must be available for each charging point.
2. b) Extension of the charging time of individual vehicles up to the situation that the user's charging destination can no longer be reached in the time available before unplugging, i.e. the vehicle cannot be fully charged.

In summary, either high additional costs for the charging hardware or restrictions in charging operation are associated with negative effects on the charging of the vehicles.

The object of the invention is therefore to provide an improved method for the method for reducing a power reference difference during the charging process of an energy store of one or more vehicles, an improved unit for reducing a power reference difference and an improved charging device.

Summary of the invention

The object is achieved according to the invention by the features of the independent claims. Advantageous further developments of the invention emerge from the subclaims.

According to the invention, this object is achieved by a method for reducing a difference in power consumption during the charging process of an energy store of one or more vehicles, the vehicles being connected to one or more charging points of a charging device with multiple phases, comprising: determining phase-specific power consumption of the charging device; and reducing at least one power consumption difference between the phase-specific power purchases by applying at least one equalizing load to at least one phase.

According to the invention, at least one additional electrical equalizing load is switched to at least one underutilized phase in order to reduce the difference in power consumption. In this way, charging can continue in the charging device without the expensive measures mentioned in a) and without the disadvantage of lengthening the charging time or charging interruption described in b).

According to the invention, a charging device can also be understood to mean a charging cluster with several charging points.

The inventive determination of phase-specific power purchases of the charging device preferably also includes ascertaining the at least one power purchase difference from the ascertained phase-specific power purchases.

It is conceivable that the additional load switching on the respective phases can in principle take place via any type of single-phase electrical loads that can be activated, for example, either on / off or controllably by a control unit and that are permanently assigned to a phase.

It is particularly preferable for the equalizing load to be applied to the phase with the lowest load. Since the difference in service consumption is greatest here, it is particularly advantageous to reduce the difference in service consumption in the phase with the lowest load.

In a particularly preferred embodiment, the method according to the invention further comprises determining if a limit value for the power consumption difference between the phase-specific power purchases is exceeded, the equalizing load when reducing the power consumption difference is such that the power consumption difference is reduced to a value less than or equal to the limit value. The charging operation of the charging device is thus ensured in an advantageous manner when the charging operation is regulated by limit values.

In one embodiment, each phase has at least one compensating load that can be added. In this way, it is possible to react flexibly to an unbalanced load.

In another embodiment, the equalizing load is switched on by means of a phase switch. As a result, only a balancing load needs to be provided.

In a particularly preferred embodiment, the equalizing load is designed such that electrical energy is converted into another form of energy. The equalizing load is advantageously formed by a heating element, a cooling element, a compressed air element, a hydraulic element, a storage element for kinetic energy, a storage element for positional energy and / or an element for conversion into chemical energy.

1. a) Umwandlung in Wärme über schalt- oder regelbare Heizstäbe und ggf. Speichern in Pufferspeichern von Heizsystemen oder Brauchwassersystemen;
2. b) Umwandlung in Kälte über Kältemaschinen und ggf. Nutzung Kältespeicher;
3. c) Umwandlung in Druckluftenergie und ggf. Speicherung in Druckspeichern;
4. d) Umwandlung in hydraulische Energie und ggf. Speicherung in Druckspeichern
5. e) Umwandlung in mechanische Bewegungsenergie (z.B. Schwungradspeicher etc.) - oder Lageenergie (z.B. Pumpspeicher); und/oder
6. f) Umwandlung in chemische Energie über Wasserstoffelektrolyse, power to gas oder power to liquid Verfahren.

In terms of energy economy, the additional load is advantageously designed so that as little or no energy loss as possible occurs. This leads to the application of the concept of sector coupling as an object of the invention in connection with the unbalanced load limitation of charging processes. This means that the additional electrical energy used in the charging device for unbalanced load compensation is used in such a way that it can be used for another application purpose. For example, the following applications come into consideration, in particular if the charging device is designed in connection with living spaces, business premises, factory buildings, etc.:

1. a) Conversion into heat via switchable or controllable heating elements and, if necessary, storage in buffer storage of heating systems or domestic water systems;
2. b) Conversion into cold via refrigeration machines and, if necessary, use of cold storage;
3. c) Conversion into compressed air energy and, if necessary, storage in pressure accumulators;
4. d) Conversion into hydraulic energy and possibly storage in pressure accumulators
5. e) Conversion into mechanical kinetic energy (e.g. flywheel storage etc.) - or position energy (e.g. pump storage); and or
6. f) Conversion into chemical energy via hydrogen electrolysis, power to gas or power to liquid processes.

In general, the converted energy is preferably stored in an energy store. But it is also conceivable that the converted energy is consumed immediately.

Depending on the operating context of the charging infrastructure, the most sensible of the above options can be selected. The simplest version of generating heat, for example using heating rods, is often the best option, since a charging infrastructure is often created in spatial connection with residential or commercial buildings.

In a further preferred embodiment, the method further comprises determining if a limit value for the power consumption difference between the phase-specific power purchases is exceeded, and if the equalization load is not sufficient for the power consumption difference to be reduced to a value less than or equal to the limit value, reducing one or more phase-specific power draws from charging processes in the charging cluster, so that the power draw difference is reduced to a value less than or equal to the limit value. By using the equalizing load, the known reduction of phase-specific power consumption can be reduced, resulting in overall reduced charging times for the charging device with the equalizing load according to the invention.

In a particularly preferred embodiment, the method also includes an additional connection of a further equalizing load to the second-weakest loaded phase.

According to the invention, a unit for reducing a difference in power consumption is provided for carrying out the method for reducing a difference in power consumption during the charging process of an energy store of one or more vehicles. This unit comprises a determination module for determining phase-specific power consumption of the charging device; and a control unit for reducing at least one power consumption difference between the phase-specific power purchases by applying the at least one equalizing load.

Furthermore, according to the invention, a charging device with a plurality of phases is provided, having one or more charging points for charging an energy store of one or more vehicles, the charging device having a previously described unit. The charging device is, for example, a fleet charging device that has several charging points to which one or more vehicles, in particular electric vehicles, are connected.

Figure list

• 1 eine schematische Ausführungsform des erfindungsgemäßen Verfahrens mit einer erfindungsgemäßen Einheit zur Reduktion einer Leistungsbezugsdifferenz bei einer Ladeeinrichtung, und
• 2 eine andere schematische Ausführungsform des erfindungsgemäßen Verfahrens mit einer erfindungsgemäßen Einheit zur Reduktion einer Leistungsbezugsdifferenz bei einer Ladeeinrichtung.

Embodiments of the invention are described below with reference to the figures. Show:

• 1 a schematic embodiment of the method according to the invention with a unit according to the invention for reducing a power reference difference in a charging device, and
• 2 Another schematic embodiment of the method according to the invention with a unit according to the invention for reducing a power consumption difference in a charging device.

Detailed description

1 shows a charging device 30th with a first phase L1 , a second phase L2 and a third phase L3 and a first charging point 20th , a second charging point 22nd and a third charging point 24 .

While at the first charging point, for example, a three-phase charging electric vehicle 10 connected for charging are, for example, at the second charging point 22nd and at the third charging point 24 a single-phase charging electric vehicle 12 and 14th connected for charging. This puts a strain on the electric vehicle 10 all three phases L1 , L2 and L3 . The electric vehicle 12 loads the phase, for example L2 and the electric vehicle 14th loads the phase, for example L3 .

In addition, other consumers can also participate in the individual phases 16.1 , 16.2 and 16.3 be connected. It is conceivable that the power consumption of these consumers cannot be controlled.

Depending on the power consumption of the electric vehicles 10 , 12 and 14th or the consumer 16.1 , 16.2 and 16.3 There can therefore be a difference in performance between the three phases L1 , L2 and L3 occur. The phase unbalanced load is calculated using the largest difference in power consumption between the phases, where P _{Li is} the sum of all power consumed by phase i. In the embodiment of 1 the phase unbalance can therefore be caused by the largest of the power reference differences | P _L1 - P _L2 |, | P _L1 - P _L3 | and / or | P _L3 - P _L2 | be determined.

• Die Ermittlung kann zum Beispiel am für die jeweilige Regulierung relevanten Bilanzierungspunkt ermittelt werden. In der Regel ist das z.B. der Anschluss an das Versorgungsnetz mit einem Stromzähler eines Energieversorgers. Dabei ist es vorstellbar, dass die erfindungsgemäße Ermittlung durch eine Messung der tatsächlichen phasenindividuellen Leistungsbezüge erfolgt.

Various embodiments are conceivable for the inventive determination of phase-specific power consumption of the charging device:

• The determination can be determined, for example, at the balancing point relevant for the respective regulation. Usually this is, for example, the connection to the supply network with an electricity meter from an energy supplier. It is conceivable that the determination according to the invention is carried out by measuring the actual phase-specific performance payments.

In 1 is shown, for example, that the phase-specific service payments with a determination module 60 be determined.

However, embodiments are also conceivable in which the determination according to the invention takes place by means of forward-looking planning, with the anticipated power consumption being determined in advance. This can be done using, for example Loading plans are made. Here it is conceivable that the determination module 60 is not required for measurement. It is also conceivable that the predictive planning in the determination module 60 he follows. The investigation module 60 does not have to be located at the balancing point for forward-looking planning (not shown).

For reducing a power consumption difference according to the invention between the phase-specific power purchases by applying at least one equalizing load 40 , 42 and or 44 for at least one phase L1 , L2 and or L3 is it conceivable that as in 1 shown a control unit 70 controls the activation of these equalizing loads.

In 1 are the results of the investigation module 60 to the control unit 70 transmitted. It is conceivable that the determination module 60 at least one service reference difference has already been determined from the phase-specific service payments and sent to the control unit 70 passes, or that the control unit 70 at least one difference in service receipts is determined from the phase-specific service receipts.

Thus form the determination module 60 and the control unit 70 one unity 50 to reduce a benefit receipt difference.

In 1 is shown that, for example, the equalizing load 40 the phase L1 , the balance load 42 the phase L2 and the balance load 44 the phase L3 assigned. Generally, a balance load 40 , 42 and or 44 also include several partial loads.

By applying the respective equalizing load to a phase, its power consumption is increased. If this phase had a lower power consumption than one of the other phases before the connection, the power reference difference is thus reduced after the inventive connection.

Preferably, the equalizing load is generally applied to the phase with the lowest load. In this way, the greatest difference in power reference, that is to say the phase unbalance, can be reduced in an advantageous manner.

Any consumer can be a balancing load within the meaning of the invention. Electrical energy is preferably converted into another form of energy. The converted energy can be stored in at least one energy store 48 get saved. It is also conceivable that the converted energy is used directly. For example, the equalization loads 40 , 42 and 44 formed by heating elements provided by the control unit 70 are controllable.

In 1 is also shown that an exchange of information between the energy storage 48 and the control unit 70 can be set up, for example, to prevent the energy store from overflowing 48 to prevent general feedback to the control unit 70 to give, and / or to the energy storage 48 to prepare for an energy intake.

2 FIG. 11 shows an embodiment similar to FIG 1 , in which only a single-phase equalizing load 40 all three phases L1 , L2 and L3 is controllably assigned. The balancing load 40 is by means of a phase switch 46 switched according to the invention.

In both figures, solid lines between the respective features illustrate a flow of information, control signals, etc., which can take place in both or in one direction. The reinforced solid lines illustrate the three phases L1 , L2 and L3 . The dashed lines show the flow of non-electrical energy.

In all embodiments, the method according to the invention also includes determining whether a limit value Pso is exceeded, which represents the upper unbalanced load limit for the power consumption difference between the phase-specific power purchases. When reducing the unbalanced load, the equalizing loads are dimensioned in such a way that the greatest difference in power consumption (unbalanced load) is reduced to a value less than or equal to the limit value Pso. Accordingly, equalization loads 40 , 42 , and or 44 switched according to the invention so that all of the following conditions are met: | P _L1 -P _L2 | <= P _SO , | P _L1 - P _L3 | <= P _SO and / or | P _L3 - P _L2 | <= P _SO .

It is conceivable that the method according to the invention carries out the following steps in this case: If there is a violation of the unbalanced load criterion (limit value Pso) or a safety distance to the limit Pso is exceeded, the level of an additional equalizing load is applied for the weakest loaded phase 40 which is at least so large that the unbalanced load criterion for the difference in power consumption between this phase and the most heavily loaded phase is complied with. The maximum load is to be dimensioned in such a way that the difference in power consumption is zero. Depending on which phase was identified as the least loaded, the additional load is activated by activating the equalizing load on the respective phase 40 , 42 or 44 realized.

Furthermore, the method can be carried out in the same way for the phase that previously had the second weakest load.

However, the following case is also conceivable: If the above measures do not lead to the unbalanced load criterion being met because the available equalizing loads are limited, load management measures must also be used to intervene in the charging processes of the vehicles. This means that the power consumption of the phases that are still too heavily loaded must be reduced by actively reducing at least one charging power of one or more electric vehicles charging on this phase, in particular of single-phase charging electric vehicles.

According to the invention, the method provides for determining that the limit value Pso for the power consumption difference between the phase-specific power purchases is exceeded, and if the at least one equalizing load 40 , 42 and or 44 is not sufficient so that the power consumption difference is reduced to a value less than or equal to the limit value Pso, reducing one or more phase-specific power purchases, so that the power consumption difference is reduced to a value less than or less than or equal to the limit value Pso.

The reduction of one or more phase-specific service purchases is preferably carried out via a load management unit 72 controlled.

Between the control unit 70 and the load management unit 72 an exchange of information is preferably set up via which the load management unit 72 can see that the control options of the control unit 70 the additional loads have been exhausted. This can for example be caused by the design performance limits of the at least one equalizing load 40 , 42 and or 44 be conditioned or by operating conditions of the system. It is conceivable that the energy store 48 is not capable of receiving the converted electrical energy. In order to be able to recognize this, it is also conceivable that an exchange of information between the energy store 48 and the control unit 70 is set up.

It is also conceivable that the control unit 70 the at least one equalizing load 40 one from the load management unit 72 be an independent unit or be combined with it.

As mentioned above, a planning process can be used in addition to and in parallel to the reactive approach described, for example if the energy requirement and / or the planned departure time of the charging vehicles are known and if the usable performance potential of the equalizing loads can be planned in advance (e.g. on the basis of constructive Parameters, storage capacity).

In a planning mode of operation, depending on the potential energy consumption per phase, it is possible to plan in advance which contribution the at least one equalizing load will make 40 , 42 and or 44 can deliver for unbalanced load reduction.

In this case, it is possible, in the case of the advance planning reduction of a power reference difference via the charging power control according to the invention, that the contribution of the at least one equalizing load that is possible in planning 40 , 42 and or 44 can be taken into account as a reduction in the unbalanced loads to be expected in planning. As with reactive intervention, this reduces the need or level of charging power reductions as a means of control with their potential negative consequences.

In summary, the use according to the invention enables at least one equalizing load 40 , 42 and or 44 the disadvantages mentioned above can be avoided or alleviated. In many cases, simple and inexpensive means can be used and energetic use in other sectors can be ensured.

List of reference symbols

10

first vehicle

12

second vehicle

14th

third vehicle

16.1

first consumer

16.2

second consumer

16.3

third consumer

20th

first charging point

22nd

second charging point

24

third charging point

30th

Charging device

40

first equalizing load

42

second equalizing load

44

third balancing load

46

Phase switch

48

Energy storage

50

Unit for reducing a difference in benefit receipts

60

Investigation module

70

Control unit

72

Load management unit

L1

first phase

L2

second phase

L3

third phase

Claims (11)

Method for reducing a difference in power consumption during the charging process of an energy store of one or more vehicles (10, 12, 14), with the vehicles at one or more charging points (20, 22, 24) of a charging device (30) with several phases (L1, L2, L3 ) are connected, including: Determining phase-specific power consumption of the charging device; and reducing at least one power consumption difference between the phase-specific power purchases by applying at least one equalizing load (40) to at least one phase (L1, L2, L3). Procedure according to Claim 1 , whereby the equalizing load is applied to the phase with the lowest load. Procedure according to Claim 1 or 2 , further comprising: determining if a limit value for the power consumption difference between the phase-specific power purchases is exceeded, the equalizing load (40) when reducing the power consumption difference is dimensioned such that the power consumption difference is reduced to a value less than or equal to the limit value. Method according to one of the preceding claims, wherein each phase has at least one compensating load (40, 42, 44) that can be added. Method according to one of the Claims 1 to 3 , wherein the equalizing load (40) is switched on by means of a phase switch (46). Method according to one of the preceding claims, wherein the equalizing load is designed such that electrical energy is converted into another form of energy. Procedure according to Claim 6 , the equalizing load being formed by a heating element, a cooling element, a compressed air element, a hydraulic element, a storage element for kinetic energy, a storage element for position energy and / or an element for conversion into chemical energy. Method according to one of the Claims 1 , 2 or 4th to 7th , further comprising: determining if a limit value for the power purchase difference between the phase-specific power purchases is exceeded, and if the equalization load (40) is not sufficient for the power purchase difference to be reduced to a value less than or less than or equal to the limit value, reducing one or more phase-specific power purchases, so that the difference in power consumption is reduced to a value less than or equal to the limit value. The method according to any one of the preceding claims, further comprising: additional connection of a further equalizing load (42, 44) to the phase with the second weakest load. Unit (50) for reducing a power consumption difference for carrying out the method according to one of the preceding claims, comprising a determination module (60) for determining phase-specific power consumption of the charging device; and a control unit (70) for reducing at least one power consumption difference between the phase-specific power purchases by switching on the at least one equalizing load. Charging device (30) with several phases (L1, L2, L3), having one or more charging points (20, 22, 24) for charging an energy store of one or more vehicles (10, 12, 14), the charging device (30) being a Unit (50) according to Claim 10 having.

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