DE102017212785A1 - Phase unbalance minimization - Google Patents

Abstract

Phase unbalance minimization unit, a method for phase unbalance minimization during charging of an energy storage of one or more vehicles, and an associated charging cluster. The phase unbalance minimizing unit includes a stationary storage system, a terminal unit connecting the stationary storage system to a charging cluster for charging one or more vehicles, and a control unit configured to reduce or increase the load of the individual phases by storing or storing energy from the stationary storage system, so that during the charging of an energy storage of the one or more vehicles a phase unbalance criterion is met.

Description

The invention relates to a phase unbalance minimization unit, a method for phase unbalance minimization during the charging process of an energy store of one or more vehicles, and an associated charging cluster.

When charging single-phase charging electric vehicles, the phases can be loaded asymmetrically in three-phase networks. From the point of view of network operation, upper limits for the asymmetry of the phase load in regulations, e.g. Connection conditions for systems on the power grid, defined to ensure trouble-free network operation.

It is an object of the present invention to provide an improved apparatus and method for phase unbalance minimization.

The achievement of the object of the invention is achieved by the features of the independent claims. Advantageous developments of the invention will become apparent from the dependent claims.

The invention is based on the following knowledge: When charging single-phase charging electric vehicles (BEV's and PHEV's), the phases can be loaded asymmetrically in three-phase networks. Upper limits for the asymmetry of the phase load, the so-called phase unbalance or phase unbalance, are defined. Usually, the difference of the powers on the outer conductors is limited, e.g. on max. 3.7kVAfor a system behind a connection point, also called counter.

It may happen that a single-phase charging vehicle with a charging capacity above the applicable limit exceeds it. Even in a charging situation with multiple vehicles on a charging cluster, this limit can be exceeded. This happens when the vehicles for loading randomly select places with associated charging points and thus the individual assignment of the terminals of the charging station or charging points to the phases of the three-phase supply network, so that it may come to exceed the limit. This results in a random load situation on the individual phases with a possible exceeding of the asymmetry limit even if the charging power of the individual vehicle remains below the limit. For example, three single-phase vehicles with 3.7KW charging power on a first phase L1 and only one vehicle on the second phase L2 and third phase L3 give a unbalanced load of 7.4 kW.

By phase rotation devices that can switch the assignment of the charging phases to the connection phases with the help of additional hardware such as contactors or power electronics depending on the phase utilization, can be tried to prevent exceeding the unbalanced load limit. These measures, however, lead to additional costs in the charging infrastructure.

Furthermore, it can be ensured by load-limiting interventions on the individual charging processes, for example by a control device, that the unbalanced load limits in the overall system are maintained. However, this may extend the charging time of individual vehicles, for example, up to the situation that the charging target of the customer of the vehicle in the available time can no longer be achieved, so the vehicle can not be fully charged.

The reason for this is that there is always a phase whose power consumption goes from very low to zero or zero as the vehicles have finished loading. As a consequence, only services that correspond to the maximum unbalanced load limit on the other phases may be used, no matter how many vehicles still have to be completed on the respective phase. Since it is only possible to control the charging power via a controllable charging infrastructure, this means can only intervene via this means, so that a situation results for the remaining vehicles that can only be charged with very low power. Since the base standard for charging IEC61851 also provides a minimum charging power, which corresponds to approximately half of a load unbalance limit of 3.7kVA in the example, only two vehicles can be loaded per phase, while the others have to pause.

It can then happen that the charging infrastructure is used inefficiently, charging processes can be extended and even the risk that vehicles will not be fully charged until the user puts the vehicle out again.

The measures according to the invention specify a phase unbalance minimization unit comprising a stationary storage system, a connection unit which connects the stationary storage system with a charging cluster for charging one or more vehicles, a control unit which is set up by storing or storing energy from the stationary storage system reduce or increase the individual phases, so when charging an energy storage of one or of the multiple vehicles, a phase unbalance criterion is met.

In a further development of the phase unbalanced load minimizing unit, it is provided that the control unit can reduce or increase the charging power of vehicles. This also leads to compliance with the phase unbalance criterion is guaranteed.

The phase unbalance minimization unit provides in a further development of a stationary storage system which comprises three single-phase connected inverters each having a battery. The respective inverter of the three batteries or its power electronics is designed so that the respective battery can be controlled separately via a common control unit for storing or storing energy.

In another development, the stationary storage system of the phase unbalance minimization unit comprises a three-phase connected inverter with a battery. The power electronics of the inverter of the battery is designed so that the inverter for storing or storing energy can be controlled separately per phase via a control device.

The inverters controlled by the control unit are arranged so that the setpoint specifications of the control unit for drawing energy or supplying energy are converted into the respective phase.

The stationary storage system is further adapted for caching solar energy. In a further development, the stationary storage system for load peak limitation is set up in connection with charging processes. In a further development, the stationary storage system is for the provision of energy or network related services such. Control energy or reactive power provision set up. The stationary storage system may comprise a combination of two or all three of these mentioned developments.

The stationary storage system is designed to carry out the intermediate storage of solar energy in parallel with the storage or withdrawal of energy for the unbalanced load control. This also applies to the peak load limitation in connection with charging processes or for the provision of energy-related or network-related services. The control unit is set up in parallel to the unbalanced load control, to carry out the temporary storage of solar energy, the peak load limitation or the provision of energy-related or network-related services.

The storage capacity of the stationary storage system is set up in a further development both for the maintenance of the phase unbalance criterion and / or for the temporary storage of solar energy and / or the provision of energy-related or network-related services. The proportion of the storage capacity for compliance with the phase unbalance criterion as well as the proportion of the storage capacity for the storage of solar energy, for load peak reduction or energy-related interactions can be determined adaptively. For this purpose, measurements are made and data is determined, after which it is determined how much unbalanced load is required in the battery capacity in a charging cluster or charging device experience has shown. However, it is also possible to proportionally set the division of the storage capacity, e.g. to provide half for the unbalanced load limit and the remaining half as a buffer for solar energy and / or load peak reduction and / or energy-related interactions.

The measures according to the invention furthermore specify a method for phase unbalance minimization 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 cluster. The method comprises the steps:
Determining the phase-specific power reference of the charging cluster at a connection point of the charging cluster. Determining a phase unbalance. Determining a phase individually reducing or increasing the respective reference power at the connection point of the charging cluster by storing or storing energy in or out of a stationary storage system, so that during the charging process of the energy storage of the one or more vehicles, a phase unbalance criterion is met. When determining the phase-specific power consumption of the charging cluster, the current services at the connection point are determined. From this, the resulting phase unbalance is determined.

In a further development of the method, the influencing of the charging power of individual vehicles is provided to ensure compliance with the unbalanced load limit, so that the phase unbalanced load criterion is met.

The method according to the invention enables phase-specific determination of the power reference of the charging cluster at the connection point of the charging cluster. It is first determined the power received by the one or more vehicles to charge its energy storage becomes. If the method is carried out in a control device of a charging cluster, or in the control unit of the phase unbalance minimization unit, the current power reference of the system (charging cluster or charging device) is determined by phase-specific measurement. This determines whether a load unbalance is to be regulated. In other words, it is determined whether, during the charging process of an energy store of the one or more vehicles, which are connected to charging points of the charging cluster, a phase unbalance criterion is met or an intervention is required. If intervention is required, the reference power at a connection point of the charging cluster is reduced or increased by storing or discharging energy into or out of the stationary storage system.

The measurement of the benefit is based on the relevant accounting point for the respective regulation. As a rule, the connection point to the supply network with one of the electricity meters of an energy supplier.

The method for phase unbalance minimization also provides that regulatory interventions on the stationary storage system or changes in charging power only take place when the phase unbalance criterion for the respective connection phase is exceeded.

In a further development of the method, in the case of three connection phases it is determined which two connection phases have a higher charging power than a third connection phase and energy is fed from the stationary storage system to the two connection phases with a higher charging power if the phase unbalance criterion for the respective phase is exceeded. It is fed at least as much power as the difference of the current phase power to the power of the weakest loaded phase. The maximum amount of power is fed in as the stationary storage system provides due to the design or due to the state of charge.

If the phase unbalance criterion continues to be violated after energy has been fed to the respective phase, an additional load is generated by charging the stationary storage system to the weakest terminal phase. This again complies with the phase unbalance criterion. The measure of the additional load is defined by the necessary compensation power and is possibly limited by the system parameters and the battery condition.

In a further development of the method, it is provided that load management measures are also provided for maintaining the phase unbalance criterion. In this case, the power consumption of a phase under excessive load is reduced by actively reducing the charging power of single-phase charging vehicles on this phase. First, the respective phase is determined, which is loaded at one or more charging points of the charging cluster. The respective charging power at the associated connection phase is determined. A charging or loading schedule for each of the one or more vehicles is established based on the determined number of phases and / or loaded phases and their utilization and the prevailing unbalanced load. The charging or charge planning is done in such a way so that the charging process of the energy storage of one or more vehicles a unbalanced load criterion is met.

With such a load management, the predetermined maximum unbalanced load of a charging infrastructure with a plurality of charging clusters behind a connection point, for example the connection point to a power grid, of, for example, 3.7 kVA can be ensured. The predetermined unbalanced load limit may be specified by a network operator or by an operator of the charging cluster or may be specified in other ways. By connection point to the network is meant the point of connection of the charging cluster to the electrical energy supply network. The number of phases that are charged at one or more charging points of the charging cluster is determined by measuring the power during the charging process, during an initialization phase at the beginning of the charging process via counters or power meters. The measured values can be used to determine the number of loaded or used phases. Furthermore, the phase connections of the individual charging points (assignment of the power-transmitting contacts to the phases of the connection point) can be stored in a database, so that the information on which connection phase is loaded, for example, in single-phase charging already exists. In a later repeated single-phase charging for charging the energy storage of the vehicle, the information of the connection phase can be used directly from the database and a re-determination of the connection phase can be omitted.

The loading plan includes the specification of a maximum charging power over a given or calculated period of time. It is created for each vehicle whose energy storage is to be charged. The charging schedule of each vehicle includes a load default (power demand) for the current time or a load schedule for the presence of the vehicle at the charging point while its energy store is being charged. In load planning for one or more vehicles, an anticipated unbalanced load is preventively prevented. Of the Loading plan for each individual vehicle can be implemented in different ways: As a performance target by communication means to a charging point, which is adapted to limit the charging power, possibly in conjunction with the vehicle. Or by communication with the vehicle, which itself implements the power limitation (eg using ISO15118)

In addition, a pre-planning method can be used if the charging requirements of the charging vehicles and the planned departure time are known and the stationary storage system is aware of the energy content available for phase-specific interventions.

In a pre-planning operating mode, depending on the usable energy content or the potential energy consumption of the stationary storage system, it can be planned in advance for each phase what contribution the stationary storage system can make to the unbalanced load limitation.

In the method of the pre-planning unbalanced load limitation via the charging power control, the planned contribution of the stationary storage system can be taken into account as a reduction of the planning-related unbalanced loads. This reduces the need for charging power reductions as a means of control with their potential negative consequences.

The measures according to the invention furthermore specify a charging cluster, comprising one or more charging points for connecting one or more vehicles, a phase unbalance minimization unit, wherein a phase unbalance criterion is maintained during the charging process of an energy store of the one or more vehicles.

The phase unbalance minimization unit may be connected at a connection point to a three-phase network. The method according to the invention is carried out by the phase unbalance minimization unit.

By integrating a stationary storage system in the charging cluster or charging device with multiple charging points, a method can be applied, with which one can actively ensure compliance with the load unbalance loading. In other words, the presence of a phase unbalance minimization unit in a charging cluster ensures that the phase unbalance criterion is met when charging an energy store of the one or more vehicles.

In a further development, the charging cluster comprises a device for storing solar energy, for reducing load peaks and / or for providing energy-related or network-related services.

A charging cluster has several charging points connected at a common reference point in terms of power cap and unbalanced load. In addition to charging points, a charging cluster can also contain control functions. These can be arranged both in a separate unit, as well as in a charging point or in a backend.

A charging point is a charging device for charging a single electric or plug-in hybrid vehicle (all statements regarding electric vehicles relating to the invention also apply to plug-in hybrid vehicles and vice versa). The charging point is in the context of this invention set up so that it can be addressed via communication means and set by interaction with the connected vehicle a predetermined charging power.

Specific embodiments of the invention will now be described with reference to the accompanying drawings. However, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully disclose the scope of the invention to a person skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like characters refer to like elements.

• 1: ein Ausführungsbeispiel einer Phasen-Schieflastminimierungseinheit;
• 2A: ein Ausführungsbeispiel eines Stationärspeichersystems;
• 2B: ein Ausführungsbeispiel eines anderen Stationärspeichersystems;
• 3: ein Ausführungsbeispiel eines Verfahrens zur Phasen-Schieflastminimierung;
• 4: ein Ausführungsbeispiel eines Ladeclusters.

Show it:

• 1 an embodiment of a phase unbalance minimizing unit;
• 2A an embodiment of a stationary storage system;
• 2 B an embodiment of another stationary storage system;
• 3 an embodiment of a method for phase unbalanced load minimization;
• 4 : an embodiment of a charging cluster.

1 shows a phase unbalance minimization unit 1 with a stationary storage system 2 , a connection unit 3 and a control unit 4 , The connection unit 3 connects that Stationary storage system 2 with a loading cluster 10 for charging energy storage 8a . 8b one or more vehicles 5a . 5b , The loading cluster 10 is via a connection point (reference point) 11 with a three-phase supply network 12 connected. For a better overview, the phase unbalance minimization unit 1 Larger than the load cluster 10 , The vehicles 5a . 5b are with the load cluster 10 each connected via a charging point.

The control unit 4 is designed to reduce or increase the load on individual phases by storing or removing energy from the stationary storage system 2 , The control unit 4 may be the charging power of the one or more vehicles 5a . 5b decrease or increase.

2A shows an embodiment of a stationary storage system 2 , The stationary storage system 2 has three single-phase connected batteries 6a . 6b . 6c on each with a single-phase inverter 7a . 7b . 7c ,

2 B shows an embodiment of another stationary storage system 2 , which is a three-phase connected battery 6 with a three-phase inverter 7 includes.

The stationary storage system 2 is set up for caching solar energy. For example, storing solar energy in one of the batteries 6a . 6b . 6c out 2 respectively. Alternatively, the storage capacity of the stationary storage system 2 out 2 or 3 For example, 50% for solar energy provided. The solar storage system 2 may also be set up to limit peak loads in connection with charging or to provide energy or network related services. Also, this is a certain storage capacity of the stationary storage system 2 intended. The storage capacity for solar energy, load peak limitation and grid related services can also be provided adaptively based on empirical data. The injection / withdrawal of energy into the stationary storage system 2 takes place parallel to the procedure for compliance with the phase unbalance criterion.

3 shows an embodiment of a method for phase unbalanced load minimization. Initially, the benefit reference is at a connection point 12 of the load cluster 11 determined phase-individually S1 , From this, the resulting phase unbalance is determined S2. In the next step S3 For example, a need for phase-individually decreasing or increasing the respective reference power at a connection point of the charging cluster is determined and this by storing or storing energy in or out of a stationary storage system 2 implemented as a corrective intervention, so when charging the energy storage 8a . 8b one or more vehicles 5a . 5b , a phase unbalance criterion is met.

At three connection phases, in step S4 Determines whether two connection phases have a higher charging power than the third connection phase. Energy can then be transferred from the stationary storage system to the two connection phases with a higher charging power 2 be fed.

If the phase unbalance criterion continues to be violated after energy is applied to the respective phase, step S5 , may, in a further development of the method, on the weakest busy connection phase, an additional load by loading the stationary storage system 2 be generated, step S6 ,

In a further development of the method, a load management measure is provided for maintaining the phase unbalanced load criterion, step S7 , In this case, the power consumption of a too high-loaded phase by active reduction of the charging power of on this phase single-phase charging vehicles 5a . 5b reduced.

4 shows an embodiment of a charging cluster 10 , The loading cluster 10 is via a connection point (reference point) 11 with a three-phase supply network 12 connected. The loading cluster 10 has several charging points 9a . 9b . 9c . 9d to connect one or more vehicles 5a . 5b . 5c . 5d and a phase unbalance minimization unit 1 on. The charging cluster is set up so that when charging an energy storage 8a . 8b . 8c . 8d one or more vehicles 5a . 5b . 5c . 5d , a phase unbalance criterion is met.

The phase unbalance minimization unit 1 is connected at a connection point to a three-phase network. The inventive method is of the phase unbalance minimization unit 1 of the load cluster 10 executed. Through the integration of the stationary storage system 2 the phase unbalance minimization unit 1 into the charging cluster with several charging points 9a . 9b . 9c . 9d Active compliance with the unbalance limitation during loading is effected.

In summary, devices and methods are given by which the previously known disadvantages of the unbalance limitation can be avoided or mitigated using a stationary storage system. At the same time, a stationary storage system can be used by said storage of solar energy and load peak limitation or energy / network services in conjunction with charging, so that synergies can be generated in terms of investment costs.

It should be understood that the methods, devices and systems described herein may be used alone as well as in combination with other methods, devices and systems described in this document. Furthermore, any aspects of the methods, apparatus, and systems described herein may be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways.

Claims (10)

Phase unbalance minimization unit (1) comprising a stationary storage system (2), - A terminal unit (3), which connects the stationary storage system with a charging cluster (10) for charging one or more vehicles (5a, 5b), and a control unit (4) which is set up to reduce or increase the load on the individual phases by storing or storing energy from the stationary storage system, so that a phase unbalance criterion is met during the charging process of an energy store of the one or more vehicles. Phase unbalance minimization unit after Claim 1 wherein the control unit is further configured to decrease or increase the charging power of the one or more vehicles. Phase unbalance minimization unit after Claim 1 or 2 , wherein the stationary storage system comprises three single-phase connected inverters (7a, 7b, 7c) each having a battery (6a, 6b, 6c). Phase unbalance minimization unit after Claim 1 or 2 , wherein the stationary storage system comprises a three-phase connected inverter (7) with a battery (6). A phase unbalance minimization unit according to any one of the preceding claims, wherein the stationary storage system is adapted for caching solar energy. Phase unbalanced load minimization unit according to one of the preceding claims, wherein the stationary storage system for load peak limitation in connection with charging operations or for the provision of energy or network-related services is set up. A method for phase unbalance minimization during the charging process of an energy storage device of one or more vehicles, the vehicles being connected to one or more charging points of a charging cluster, comprising the steps of: - phase-individual determination (S1) of the services related to a connection point of the charging cluster, - determining (S2) a phase unbalance, and Determining (S3) phase-individually reducing or increasing the respective reference power at a connection point of the charging cluster by storing or storing energy in or out of a stationary storage system, so that the charging process of the energy storage of the one or more vehicles, a phase unbalance criterion is met. Method for phase-unbalance minimization after Claim 7 , wherein at three connection phases, is determined (S4), which two connection phases have a higher charging power than a third connection phase and is fed to the two connection phases with higher charging power energy from the stationary storage system. Method for phase-unbalance minimization after Claim 8 in which, on the weakest loaded connection phase, an additional load is generated by charging the stationary memory system (S6) if the phase unbalance criterion is violated after energy has been applied to the respective phase (S5). Loading cluster, comprising - one or more charging points for connecting one or more vehicles, and - A phase unbalanced load minimization unit, wherein during the charging of an energy storage of the one or more vehicles, a phase unbalance criterion is met.

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