DE102019214768A1 - Method and device for using free network capacities for charging electric vehicles - Google Patents

Abstract

Method and corresponding devices for operating a network line for charging batteries, the current or predicted energy consumption or profile being aggregated, the remaining free capacity of the network line being aggregated, and the remaining free capacity being distributed. The charging strategy is adapted accordingly for each battery.

Description

The invention relates to a method for the improved use of free network capacities for charging processes of electric vehicles. The existing network capacity may appear to be insufficient if only single connections or only one household connection is considered, but there is sufficient capacity when viewed globally. This improved result can be implemented using the inventive method. The invention also relates to a corresponding device in order to better utilize existing current capacity.

Network capacities are typically determined rigidly using simultaneity factors and permanently allocated capacities. Dynamic distributions are not provided and are not possible with the existing system.

Intelligent energy management, also known as “Smart Grid”, can be used to better balance energy consumption and to better utilize the existing network capacities. At the same time, this ensures better system stability. Decentralized control of generating units, storage systems and consumers can help to increase the utilization and security of the energy network. In the best case scenario, controllable consumers can mainly obtain electricity when, for example, regenerative energy is available in abundance or offer storage options for excess electricity from renewable energy sources and ensure system stability by stabilizing voltage fluctuations (or reactive power) through targeted local feeds, for example, which is beneficial to the grid support local network.

This requires a high-performance communication protocol between the electric car, charging station, network connection point or network operator / energy supplier (and the systems behind it). For example, the ISO / IEC 15118 standard “Road Vehicles - Vehicle-to-Grid Communication Interface” or “OCCP” offers such an interface.

The parameters relevant for the charging process can be negotiated via such an interface. These include, among others. the amount of energy required, the departure time foreseen by the user, maximum and minimum charging currents, and possibly tariff tables that allow cost optimization of the charging process. A personalized user profile can also support comfort and mobility.

A load limit curve specifies what the maximum charge current limit for mains power is at any given time. The load limitation is mostly based on the local technical restrictions of the network, house connection and charging points. In emergency situations, the network operator intervenes to stabilize and is forced to switch off large feeds or switch off consumers (streets, districts ...). It can be assumed that such interventions will increase in the future due to the fluctuating power supply due to the introduction of renewable energies.

Free network capacities are determined at different levels or levels. Single household, multi-family household, network line, etc. In principle, a network with network capacity can be determined for every possible measuring point if the measurement technology is installed there (in the future, for example, “smart meters”). This can be used to determine the free network capacities. You know the connected load or the protection, and the current consumption in certain time slices or at certain points in time. This results in unused connection loads at a connection point. If one then looks at the performance of the different levels, free capacity from levels above can be released or switched off for the lowest level.
Thus, viewed in a household, the connection can be used to the maximum for a charging process without creating disadvantages (such as undesired shutdowns, network destabilizations, etc.) that are necessary for normal consumption of energy. This freely available charging power can then be made available with a suitable safety discount (eg 10%) for charging management of EVs as a maximum target value.

The free remaining capacity can be determined currently or predictively, then it results from the sum of the current or predicted consumption from several connection points or end points of the network line.

Predictive charging power estimates the required charging power for the near future in advance. For a prediction of the charging power, of course, data from the past is necessary. Alternatively, extrapolations based on simulations or classifications / groupings can be used. These are saved in order to predict future behavior.

This system can also be scaled up to the network line. The maximum limiting value is then not the house connection power, but the feed-in power of the transformer. The maximum voltage drop on the last household should also be taken into account if possible.

The charging strategy of the individual vehicle adapts to the information provided. During this process, additional capacities can be distributed if
For example, a vehicle does not need the additional services made available because either a higher-level charging strategy has no need or the battery is full.

One aspect of the invention is regulation. In the electrical path, as much as possible of the necessary energy is introduced into a battery in order to be able to withdraw it again at a later point in time. The time of charging is often irrelevant as long as the battery is fully or sufficiently charged at a certain point in time.

With an improved strategy, an unneeded capacity at one end point or connection point of the network line, a user at another connection point of the line, is credited, of course for a limited time or only with immediate effect. For example, capacity is not required at a connection point in the network line if the electric car is fully charged or charging can take place at a later time. In this way, the maximum current capacity at another connection point of the network line can be adapted for a limited time according to a charging strategy. This means that the full (remaining) power of the network line can be made available at a connection point.

This strategy can also have a positive effect on network stability. This means that user profiles are not fluctuating and fluctuations in demand or in the reported demand are largely excluded. In the best case scenario, the fluctuation is "regulated" by an adapted charging management system so that there is a constant energy requirement. This energy requirement can then have a network stabilizing effect.

The free network capacities can be distributed on the basis of various strategies. A points-based system, a traffic light-triggered system, a personalized one
System, a uniformly distributed system, a demand-driven system, etc.

Advantages include a reduction in the investment requirement in the infrastructure side, increased charging power for the end customer (for example beyond the connection power) and better utilization of the existing network capacities. Furthermore, a more constant usage profile and controllability also result in improved network stability (e.g. cosPHI).

Figure list

Embodiments of the invention are explained in more detail below with reference to schematic drawings.

• 1a und 1b ein Netzstrang und seine freie Restkapazität;
• 2a, 2b, 2c, 2d, 2e Haushaltsanschlüsse samt Absicherungen;
• 3 einen Ablauf der Adaption einer Ladestrategie;
• 4a und 4b das Aufteilen von zusätzlicher Kapazität;
• 5 die maximale Leistung der einzelnen Anschlüsse; und
• 6 die erhöhte Anschlussleistung.

Show it:

• 1a and 1b a network line and its remaining free capacity;
• 2a , 2 B , 2c , 2d , 2e Household connections including safeguards;
• 3 a sequence of adapting a charging strategy;
• 4a and 4b sharing additional capacity;
• 5 the maximum power of each connector; and
• 6th the increased connected load.

In 1a is a house connection plan 100 pictured. The capacity of the network strand 120 is determined by the maximum power of the transformer 110 limited. The end points or connection points of the line are the allocated house connection services 131 , 132 , 133 , 134 . The endpoints can be 8 kW or 11 kW, for example. The total consumption of the network line through all assigned house connections must remain below the maximum power of the transformer for this network line. This state is ensured by appropriate fuses at the endpoints as assigned house connections.

In 1b the remaining free capacity of an endpoint or household is displayed, which enables individual consumers to be aggregated and the remaining free capacity to be determined. The household has a total capacity, 140, of a total of 11 kW, but no use is made of this total capacity, only part of it 141 is used. This leaves a remaining free capacity 142. This free capacity can be "borrowed" (by switching over) or used by other households through intelligent distribution to other households in the same network line. When 141 The diagram shows the varying electricity or energy consumption over time, resulting in a varying remaining free capacity 142 results.

In the 2a to 2e Different endpoint or household backup configurations are shown. In 2a is a normal backup 110 shown which is connected to a household 119. In typical configurations, 30 such fuses are used per household connection. Any backup 110 can be designed for 40 A, for example.

In 2 B is a backup 120 shown, which is suitable for charging an electric vehicle. The backup is also at a connection point or endpoint or household 129 connected, whereby the household can also charge the battery from an electric vehicle. The backup 120 can be rated for 120 A, for example, and three are used per household with a typical three-phase connection.

Sometimes a security concept like in the 2a used, no vehicle battery should be foreseen for charging, and a connection with a fuse concept should be used 2 B charging of vehicle batteries should be desired.

In 2c a switchable fuse is shown. In such a configuration, for example, the backup 130 be determined with 120 A, the fuse by switch 131 can be switched on. Such a connection either permanently has the increased power, which must be constantly taken into account in the overall load distribution, or it draws no power.

There are three such fuse connections per household connection 139 necessary for three-phase current.

In 2d a switchable fuse is shown. Either is the backup 140 available alone, or the backup 140 comes along with the backup 145 connected in parallel. In such a configuration, for example, the backup 140 The fuse must be determined with 40 A 145 be determined with 80 A, and both together give a nominal value of 120 A. There are three such fuse connections per household connection 149 necessary for three-phase current. In principle, this is a parallel connection, applicable for a maximum of twice the power increase.

In 2e another switchable fuse is shown. Either the backup 150 , or the backup 155 , or both can be switched on in parallel. In such a configuration, for example, the backup 150 The fuse must be determined with 40 A 155 be determined with 80 A, and both together give a nominal value of 120 A. There are three such fuse connections per household connection 159 necessary for three-phase current. A suitable time delay is necessary for opening and closing, i.e. for connecting or disconnecting the fuse 150 through the switch 151 , and for switching on and off the fuse 155 through the switch 156 .

A security concept according to 2d or 2e could be used when the household connection is either used for charging (e.g. three times fuse 145 ), or is not used for loading (e.g. three backups 140 ), or used for fast loading (e.g. three backups 140 and three backups 145 ). Sufficient remaining capacity must always be secured in the network line in order to be able to increase the power at the household connection or network end point.

In 3 shows the sequence of a process for operating a power line that can be used to charge batteries. In step 310 the current or predicted energy consumption or profile is aggregated or determined. This can be determined on the basis of a current measurement, a prediction, or a combination of both. In step 320 the remaining free capacity is aggregated or determined. The remaining free capacity of the network line corresponds to the capacity of the network line in normal operation, minus the current or expected consumption. In step 330 the remaining free capacity is distributed. For this purpose, the maximum power of the individual connection can be increased for a limited period of time.

The maximum current capacity at at least one connection point or end point of the network line is adapted for a limited period according to the charging strategy. There can also be further increases at further end points or connection points, staggered in time or - if there is sufficient excess capacity in the network line - in parallel. The sum of the maximum power of all connections must not exceed the maximum power of the network line. The increase in performance of the individual connection should be withdrawn permanently if other connections want to draw more power.

In step 340 the charging strategy is adjusted accordingly for each battery on the network string. The steps are then repeated 310 to 340 as often as desired, or periodically, or as needed.

In 4a and 4b the calculation of a method for operating a network line is shown, whereby free remaining capacity is divided among users. The one at the entry point 410 determined free residual capacity or free energy to be distributed 442 is made from the excess of available energy 440 , less actual usage 441 , determined. It can be distributed to all users connected to the system. The connection services of the individual users are increased through approval (expansion of the house connection capacity). In this way, for example, the connection load of an end point 431 , 434 , can be increased from 11 kW to 22 kW (431) or 44 kW (434). For all the rest remaining users, i.e. users about whom no information is available, the simultaneity factor is used for the number in this area and an additional buffer is calculated. If this limit is exceeded, the increased feed-in power will be withdrawn.

In 5 the maximum performance of the individual connections is shown on a time axis as an example. The drivers come home from work at similar times and plug their vehicle into the power grid; the individual connections each have a limited charging power of 11 kW (531, 534) or 8 kW (532, 533). Therefore, every car will have its own typical charging curve ( 521 , 524 ) drive through (a lot of performance at the beginning with flattening behavior). The transformer on the grid feeder sees the total power from all vehicles, i.e. a peak load at certain times. As a result, the network is temporarily loaded at or possibly over its limits. This load can be counteracted with more network expansion or with a charging strategy.

In 6th a regulated system is shown. The drivers come home from work at similar times and plug their vehicle into the power grid, time 660 . In the regulated system, different information is taken into account, such as departure time, network utilization, stability, price and vehicle constraints. In this way, the current or predicted energy consumption or profile of the network line can be aggregated. The individual connections that are used for charging 631, 634 each have a limited charging power of 11 kW at the respective charging time 621 , 624 is increased to 22 kW. Therefore, every car will have its own typical charging curve ( 621 , 624 ) drive through on the basis of 22 kW available power (a lot of power at the beginning with flattening behavior). However, the transformer at the mains supply only sees the total power from all vehicles that are charged at different times. This relieves the network or does not exceed its limits 611 burdened.

In a further embodiment, the charging power can be assigned to time ranges in which the costs are too low 612 (whereby costs can also be useful for the network) can be charged and the charging power is increased at the same time. As a result, the grid line and grid feed-in point sees less load at certain times, although the individual connection limitation or end point maximum power is increased. This load is placed on times when capacity is free. For this, however, higher endpoint loads are released there.

Under certain conditions, certain indicators can be omitted if they are taken into account. If, for example, fast loading is required because the user is in a hurry and the price does not matter, it may be possible to regulate differently. In this case, regulation can only take place according to conventional distribution and only to a limited extent with increased network connection power.

In one embodiment of the invention, an evenly distributed system can be used: the capacities are evenly distributed in the first step to all participants in the system. An adaptation takes place via the "not acceptance" and feedback to the system that the "participant" does not need any capacities.

In the second step, this means that the remaining capacity is distributed to all remaining "subscriber 1".

In one embodiment of the invention, the energy profile is determined or aggregated from the sum of the current or predicted consumption from several end points of the network line.

In one embodiment of the invention, the energy profile is determined from the sum of the current or predicted consumption from several endpoints, without calculating the charging of batteries. This can be used to differentiate between consumption that is or can be determined by a charging strategy, that is to say is controllable, and other consumption that is not controllable or at least not controllable via a charging strategy.

In one embodiment of the invention, the current or predicted energy consumption is determined on the basis of reports on consumption to be expected in the future from one or more households in the same network line. The charging strategy can also be adjusted accordingly based on the time and / or day of the week. The charging strategy can also be adapted accordingly based on a personalized profile.

In one embodiment of the invention, the charging strategy is also adapted on the basis of a predicted energy consumption or profile. The energy consumption can be predicted based on past consumption or based on expected events or both. It can preferably be provided that the charging strategy is adapted on the basis of local and temporal conditions. The charging strategy can be optimized, especially in the case of electric vehicles with batteries. For example, if the vehicle is parked in the evening and at home, it is likely that it will not be used again until the next morning. In one version, the remaining free capacity is only used during the night due to the charging strategy.

In one embodiment of the invention, the charging strategy is carried out by a central charging system. The data for the various connection points or end points is collected, and a charging strategy for each battery is drawn up and carried out.

In a further embodiment of the invention, the charging strategy is carried out in a distributed or networked manner. The data for the various endpoints are exchanged, and a charging strategy for each battery is worked out and executed in a distributed manner, with individual charging systems continuing to communicate with other charging systems in order to carry out the method.

In a further embodiment of the invention, the calculation is expanded to include the degree of freedom of feeding back energy from the electric vehicle into the energy network. With this expansion, the activated capacity of the individual connection acts as an increase in the total output of the feed-in transformer in the line. This means that services that exceed the total feed-in capacity can be called up.

In a further embodiment of the invention, the increased feedback is used specifically for network stabilization.

If a charging strategy is mentioned, it includes the aspects of charging an electric vehicle, as well as the possible feedback capability of an electric vehicle.

Claims (11)

Method for operating a power line (120) for charging batteries, wherein the current or predicted energy consumption or profile of the network line is aggregated (310); the remaining free capacity of the network line is aggregated (320); the remaining free capacity is distributed (330); and the charging strategy is adapted accordingly (340) for each battery. Procedure according to Claim 1 , wherein the maximum current capacity at at least one connection point of the network line (120) is adapted for a limited time in accordance with the charging strategy. Method according to one of the preceding claims, wherein the energy profile results from the sum of the current or predicted consumption from several connection points (120) of the network line. Method according to one of the preceding claims, wherein the energy profile is calculated from the sum of the current or predicted consumption from several connection points (120) without charging batteries. Method according to one of the preceding claims, wherein the current or predicted energy consumption is determined on the basis of reports on expected future consumption from one or more connection points (131, 132, 133, 134, 431, 432, 433, 434) of the same network line (120, 420) becomes. Method according to one of the preceding claims, wherein the charging strategy is also adapted accordingly on the basis of the time and / or day of the week. Method according to one of the preceding claims, wherein the charging strategy is also adapted accordingly on the basis of a personalized profile. Method according to one of the preceding claims, wherein the charging strategy is also adapted on the basis of a predicted energy consumption or profile. Charging system for batteries which is set up to carry out the method according to one of the preceding claims. Charging system for batteries that is set up and intended to communicate with other charging systems in order to use the method according to one of the Claims 1 to 7th to execute. Electric vehicle with batteries that is set up and intended to use the method according to any of the Claims 1 to 7th to execute.

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