DE102017127302A1 - Charging an electric vehicle - Google Patents

Abstract

A method is described for controlling the charging of an electric vehicle (4) from a charger (2) which is connected to an electrical AC supply network (6), wherein a current actual mains frequency (Fa) of the electrical supply network (6) is detected, a comfort value (K) is specified, which relates to a permissible extension of a charging duration (t-ch-max), during charging, a value (B) of an operating parameter is determined, which is based on a current state of charge of the electric vehicle ( 4), and a charging current (I-ch) output from the charger (2) to the electric vehicle (4) is set depending on the actual grid frequency (Fa), the values (B) of the operating parameter and the comfort value (K).

Description

The invention relates to a charging device for charging an electric vehicle, the charging device comprising: a connection to an electrical AC supply network, a delivery point for charging current to the electric vehicle and a control device for controlling the charging, wherein the control device is designed to charge a charging current, set the charger to the electric vehicle.

The invention further relates to a method for controlling the charging of an electric vehicle from a charger connected to an electric AC supply network, wherein a value of an operating parameter is specified, which specifies a current state of charge of the electric vehicle, and taking into account the value of the Operating parameters is delivered to the electric vehicle charging current.

For electrical AC power grids the mains frequency is an essential parameter. In the European supply network, the frequency setpoint is 50 Hz. In the event of an oversupply of electricity, the actual grid frequency rises above this value; in the case of a sub-supply, it falls below it. In particular, with the increasing use of renewable energy generation systems, such as wind power plants or solar power plants, the proportion of power generation facilities, which are subject to external influences in terms of their power output and are therefore difficult to control increases. A compensatory intervention in controllable power generation plants, such as hydroelectric power plants, gas power plants, etc., is not favorable in terms of the distribution network load and in terms of efficiency and environmental considerations. Therefore, people are increasingly looking for solutions in which the load is acted on to stabilize the grid frequency. In such solutions, the current actual grid frequency of the supply network is detected and, taking these values into account, the utility grid temporarily shuts off the grid.

There are also approaches that the consumer reduces and controls his load to stabilize the grid. Examples of such a network stabilizing approach can be found in the DE 102009041726 A1 , which provides the network stabilization at the level of a gateway, and the DE 102011122656 A1 , which proposes a junction box for an electrical consumer, which shuts off the load when the actual mains frequency is below the frequency setpoint. Such shutdown can usually be tolerated in consumers who operate a thermal load, usually due to the inertia of the thermal load. The DE 102011122656 A1 As a consumer who can be connected to the controlled junction box, he sees a refrigerator. In the publication S. Williams et al., "Evaluating the role of building thermal inertia for the provision of decentralized demand-side primary electrical frequency regulation services", Conference Paper, June 2017, Conference: Sustainable Thermal Energy Management International Conference (SusTEM2017) , in Alkmaar, The Netherlands, it is proposed to operate the heating of a building block network frequency dependent. In the publication S. Wang and T. Rui, "Supply-based feedback control strategy for air-conditioning systems for direct load control of buildings responding to urgent requests for smart grids", DOI: 10.1016 / j.apenergy.2016.10.067 , this is done with an air conditioning system.

In the case of the aforementioned approaches, it is therefore assumed that a short-term shutdown of the energy supply can be tolerated due to the inertia of the thermal load. However, this does not apply to the charging of electric vehicles for which a greater spread is desired. Here this approach would be disadvantageous.

The invention is therefore based on the object to provide an improved method for charging an electric vehicle and an improved charger, with which a network stabilizing operation without loss of comfort for the user can be realized.

The invention is defined in the independent claims. The dependent claims relate to preferred developments of the invention.

The method for controlling the charging of an electric vehicle uses a charger connected to an electric AC power supply. A current actual network frequency of the electrical supply network is detected. Furthermore, a comfort value is specified which indicates a permissible extension of a charging duration. The term "comfort" is based on an objective understanding. For a longer charging time, objectively, the comfort of the store is lower. Subjectively, however, a longer charging time can also be without loss of comfort for a user, for example if a longer period of time, for example the whole night, is available to him for charging the electric vehicle. During charging, a value of an operating parameter is determined, which relates to a current state of charge of the electric vehicle. This may be the actual level of charge or a quantity of energy still missing and to be charged, if such is deducible from the available data. However, it may also be an indirect or direct measure of the amount of energy already supplied to the electric vehicle during charging, which also relates to the state of charge, For example, a ratio of actual duration in the charging current was given to the total duration of the previous charging. A charging current supplied by the charger to the electric vehicle is set depending on the actual mains frequency, the value of the operating parameter and the comfort value.

Similarly, the charger for charging an electric vehicle provides a connection to an electrical AC supply network. Further, the charger has a discharge point for charging current to the electric vehicle and a control device for controlling the charging. The control device has an input device for inputting a comfort value, which relates to a permissible extension of a charging duration. The control device is further embodied to detect the current actual network frequency at the connection. Further, it is designed to detect a value of an operating parameter during charging, which relates to a current state of charge of the electric vehicle. Finally, the control device is also designed to set a charging current, which the charger delivers to the electric vehicle, taking into account the actual network frequency, the value of the operating parameter and the comfort value. The charger thus carries out the said method for controlling the charging of the electric vehicle or is designed for this purpose.

The network frequency stabilizing effect of the method for charging or the charger is that depending on the state of charge and depending on the comfort parameter, the actual grid frequency is more or less taken into account when setting the charging current. If the user wishes a high level of comfort by loading as fast as possible, the net frequency-stabilizing effect of the charging is accordingly more or less dispensed with. If the user is satisfied with a longer charging time, ie an objectively low comfort value, then the mains frequency stabilization is high. In this way, a user without complex programming techniques by a simple specification of the desired comfort value influence on whether the mains frequency stabilizing effect is large, small or not available. For the consideration of the actual network frequency, it is preferable to set a threshold value of the network frequency below which the charger emits no or only a reduced charging current. The threshold value in embodiments depends on the selected comfort value. If an objectively high comfort value is given, ie if the charge is to take place as quickly as possible, the threshold value is set permanently or temporarily so that a charge is carried out even if there is a lack of power in the supply network and the actual mains frequency is below the frequency setpoint. With a low comfort value, that is, a user-tolerated large charging time extension, the threshold is, however, at least temporarily selected so that only at times of oversupply of electricity, the electric vehicle is charged. Depending on the threshold value and thus with the increasing value of the comfort parameter, time shares increase in which the electrical appliance is supplied with energy from the supply network and at the same time the actual mains frequency is below the frequency setpoint. Supplying the electrical appliance at times when the actual mains frequency is below the frequency setpoint is actually to be avoided for mains frequency stabilization reasons. A power supply at these times depends on the value of the comfort parameter.

The comfort value may indicate, for example, the permissible charging time until reaching a certain charging level, for example 80%, 90% or 100%. In this case, in embodiments no exact knowledge of the battery capacity or the current state of charge is necessary. The method or charger is therefore also in so-called. Type 2 Connection systems possible in which the electric vehicle reports only the maximum allowable charging current, but not the current state of charge and / or battery capacity. The comfort value then specifies, for example, a factor for the extension compared to the technically shortest charging duration, which would be achieved with the maximum permissible charging current, regardless of the specific length of this charging duration. If the user selects the highest comfort level, a full charge is carried out with the battery completely discharged, for example in 1 hour. With the lowest comfort value, the charge can be limited to phases in which the actual mains frequency is above the frequency setpoint, ie de facto an oversupply of electricity is given and then takes up to eg 8 times as long.

A particularly simple implementation provides for the control of the charging current before a manipulated variable, which only specifies a switching on and off of the electrical appliance. In a refinement, the controller is given a manipulated variable which specifies which charge current is to be allocated. Instead of a two-point behavior, the manipulated variable then has a proportional behavior.

Especially with high-performance electrical appliances, a three-phase power supply is common. In such cases it is preferred that the manipulated variable contains three components, each component being valid for exactly one of the three phases.

In order to make the user the selection of the comfort value as simple as possible, a display is appropriate, which visualizes the selected comfort parameters, for example in a level display. A particularly simple design sees for example, a color code, the z. B. changes from blue to green and yellow to red. The lengthening of the charging time optionally does not refer to the charging time until fully charged (100%), but until reaching a specified and optionally user-adjustable charging level, for example 80% or 90%. The value of the operating parameter refers to the current state of charge of the electric vehicle. In the case of electric vehicles, which provide appropriate information about the charging level, the value of the absolute amount of energy required for the desired charging (eg full charging) of the electric vehicle can be switched off. It is then continuously determined by subtracting from the amount of energy required at the start of charging the amount of energy that was supplied during charging. So it is known at any time, which amount of energy is still needed.

In some embodiments, the charger receives no information from the electric vehicle about the current state of charge. Then, it is possible for the user to inform the controller of the charging degree of the electric vehicle that was present at the start of charging, for example via an input device. The same applies if the electric vehicle reports only the degree of charge, but not the battery capacity, so that the amount of energy actually required for full charging or reaching a certain charging level of the control device or in the implementation of the method is not known.

However, the method or the charger can also work entirely without knowledge of the current charging level and / or the battery capacity of the electric vehicle. The extension of the charging time then refers to a multiplicative factor by which the charging time is prolonged compared to the minimum duration which would be achieved with constant current supply. In such cases, it is useful in a development to determine a duty cycle. The duty cycle is defined by the percentage of charge phases in which a (e.g., maximum) charge current was delivered to phases in which no charge current was delivered. The multiplicative extension of the charging duration indicated by the comfort value then corresponds to the reciprocal of the duty cycle. Thus, with a mean duty cycle of 0.5, the charging time compared to the minimum technical duration doubled. In embodiments, therefore, during operation of the charging, the threshold is varied so as to achieve, within a predetermined time interval, an average duty cycle resulting from the reciprocal of the charging duration specified by the comfort value. For this purpose, e.g. the threshold value can be set as a function of a deviation between the current and the desired average duty cycle, or switched to continuous power supply at a certain time in the time interval. In this way, care is taken that essentially the extension of the charging duration specified by the comfort value is achieved. In fact, it will be undercut in most cases, as the electric vehicle will seldom have a charge of zero. The term "essentially" also refers to the fact that deviations can occur if at the beginning of the last interval extraordinarily few phases with delivery of charge current are, so that only at the end of the interval by a continuous current, the average duty cycle is reached. In this case, there may be a slight extension beyond the desired factor. This deviation is the smaller, the shorter one chooses the time intervals within which the average duty value is to be achieved. This principle can also be used when charging with fluctuating charging current. In the duty cycle, the charging phases are then evaluated accordingly.

In a further development of the method, it is expedient that, starting from a point in time after the start of the charge, a charging current which is as large as possible for the electric vehicle is delivered permanently. This embodiment is useful both in the variant with the consideration of the duty cycle, as well as in versions in which the battery capacity and / or the degree of charge are known. The time from which the maximum possible charging current is permanently delivered is ultimately determined by the comfort value. It is present if and only if the remaining charging time is just sufficient to achieve a desired end-of-charge state with continuous current. To initiate such continuous power phases, for example, the threshold value for the network frequency can be set to a value which is below the permissible range of fluctuation for the network frequency. In this way, a continuous power is automatically achieved. The time can be chosen in particular depending on the previously supplied amount of energy.

Of course, the above-described variants for the method for charging equally affect the charger, which may be designed in particular as a charging station. The charger is then designed to perform the described method during charging.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention.

• 1 eine Schemadarstellung einer Ladesäule zum Laden eines Elektrofahrzeugs aus einem elektrischen Wechselspannungsversorgungsnetz,
• 2 eine Schemadarstellung eines Reglers in der Ladesäule der 1 und
• 3 bis 8 Diagramme zur Veranschaulichung eines Steuerverhaltens und Ladeverlaufs.

The invention will be explained in more detail by means of embodiments with reference to the accompanying drawings, which also disclose features essential to the invention. These embodiments are merely illustrative and are not to be construed as limiting. For example, a description of an embodiment having a plurality of elements or components is not to be construed as requiring all of these elements or components for implementation. Rather, other embodiments may include alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of various embodiments may be combined with each other unless otherwise specified. Modifications and modifications described for one of the embodiments may also be applicable to other embodiments. To avoid repetition, the same or corresponding elements in different figures are denoted by the same reference numerals and not explained several times. From the figures show:

• 1 a schematic representation of a charging station for charging an electric vehicle from an electrical AC power supply network,
• 2 a schematic representation of a regulator in the charging station of the 1 and
• 3 to 8th Diagrams to illustrate a control behavior and charge history.

1 schematically shows a designed as a charging station charger 2 for charging an electric vehicle 4 from an AC electrical supply network 6 , The supply network 6 is powered by electricity generating facilities operating in a distribution network 8th are merged; in the example schematically from a wind turbine 10 and a gas power plant 12 , The supply network 6 is an alternating voltage network, for which a frequency setpoint fs is pretend. In Europe, this value is 50 Hz. If there is a supply of power, the mains frequency rises above the frequency setpoint. This can for example be the case when the wind turbine 10 works with high performance. Is on the other hand in the distribution network 8th If there is a shortage of electricity, the grid frequency in the grid drops 6 below the frequency setpoint Fs.

The charger 2 is connected to the supply network 6 shot and has a control unit 14 , which controls the operation of the charger. The control unit 14 Optionally has an input and / or output interface, eg for radio communication. The charger 14 puts on a junction box 16 Charging current ready. About a charging cable 18 is the electric vehicle 4 with the junction box 16 connected.

The control unit 14 measures a current actual grid frequency fa in the supply network 6 and take them into account when loading. The charger 2 Optionally has an input device 20 that have multiple buttons 22 or has a slider. The user presses one of the buttons to indicate his or her desire for the charging time, thereby selecting a comfort value. This may possibly also be done by radio. An optional display 24 shows about corresponding differently colored lights 26 the selected comfort level. For example, the lights can have four different colors, in particular from blue to green and yellow to red. Equally, it is also possible to display the default for the comfort parameter by a single luminous field that changes color or a numerical value, etc. A step display can be realized in various ways.

To control the charging, the control unit 14 a load regulator 28 on that in 2 is shown schematically. Input variables for the load controller 28 is next to the actual grid frequency fa also the comfort value K , Another input for the load regulator 28 is a value B an operating parameter, which refers to a current state of charge of the motor vehicle. It may, for example, the current state of charge of the drive battery of the electric vehicle 4 act. From the three input sizes mentioned, value B the operating parameter, comfort K and actual network frequency fa , determines the charge controller 28 a manipulated variable S. The manipulated variable S indicates in a simple embodiment, whether the electric vehicle 4 should be loaded or not. The manipulated variable S can therefore have a two-point behavior. In a refinement gives the manipulated variable S a varying value, for example a proportional value, which indicates which charging current to the electric vehicle 4 should be supplied.

The value of the manipulated variable S depends on all input quantities. In this case, a link is made such that with increasing comfort value to the actual network frequency fa less and less consideration is taken. So take time shares in which the manipulated variable S specifies a charge, although the actual mains frequency Fa is below the frequency setpoint fs is due, with increasing comfort requirement. In a simple case, the manipulated variable is 0 or 1 (2-point behavior), ie it is charged or not. In a refinement you get as a manipulated variable S an indication of which charging current is supplied (proportional behavior).

The operating parameter for which the value B may be different in embodiments. In embodiments in which the Electric vehicle to the charger indicates the charging level, battery capacity and maximum charging current, the operating parameter includes the calculated amount of energy, which is necessary up to an input or predetermined final charging result, such as a final charge. Alternatively, it is also possible to calculate the charging duration over which the charging current must be delivered in order to obtain the end-of-charge result. The value B of the operating parameter is then combined with the comfort value K so that the end-of-loading result is achieved within the extension of the technically minimum possible charging duration derived from the comfort value. Depending on this result, then a threshold value for the mains frequency is set, wherein at actual mains frequencies below the threshold no charge current is delivered, but only at mains frequencies that exceed the threshold. The threshold value thus provides the presetting for the manipulated variable S. For 2-point behavior according to On / Off - for proportional behavior, for example, a value that depends on the degree of the threshold value overshoot.

The effect of this threshold, which, as will be explained by way of example below, also come into consideration for other embodiments with regard to the operating parameter, is for a two-point behavior in the 3 and 4 shown. The curve in 3 shows an example of the course of the actual network frequency Fa and different thresholds SF1 and SF2 , The threshold SF1 corresponds to the frequency setpoint Fs. The charging current is then always switched on at the times t1 in which the actual mains frequency Fa exceeds the threshold value SF1 rises, and at times t2 off, in which the actual grid frequency fa below the threshold SF1 falls. At a higher threshold SF2 the charging current is switched on at the times t3 and switching off at the times t4 So if there is a noticeable oversupply of electricity in the distribution network 8th consists.

4 shows a case where the threshold SF3 is below the frequency setpoint Fs. Then, the charging current is switched on at the time t5 , At the time t6 he is turned off. This will be the electric vehicle 4 even in sections where there is actually a shortage of electricity in the distribution network 8th present, loaded. Such states can manifest themselves by linking value B the operating parameter and comfort value K result. An example is a situation in which the charge history has had very few phases in which charge current has been delivered, and the end of the desired charge duration extension resulting from the comfort value K derived, is approaching. Then, for the remaining duration of the loading on the actual mains frequency fa little or no consideration to the specification of the comfort value K to fulfill.

With regard to the most stable behavior possible, it is preferable to select the proportional behavior or specify a minimum duration for which the charging current is maintained after exceeding the threshold value and / or provide a minimum duration for which the charging current remains switched off after the threshold value has been undershot , In this way vibrations in the system are avoided. Alternatively or additionally, hysteresis may also be provided for 2-point behavior, i. select the threshold value for switching on the charging current slightly higher than the threshold value for switching off the charging current.

It is provided in embodiments, the threshold SF the grid frequency depending on the state of charge to move, for example, if it is recognized that due to the amount of energy supplied so far in terms of comfort value, the remaining time must be used to a higher proportion to the charge. The 5 and 6 show exemplarily, as the threshold SF the mains frequency as a function of the value B of the operating parameter and the comfort value K can be chosen. 5 shows a straight-line curve that is shifted depending on the comfort value. At a low default K1 the curve is higher; it only becomes higher actual network frequencies fa switched on. For a higher comfort requirement and correspondingly higher specification K2 or K3 the curve is lower so that it switches on earlier. An analogous approach, however, with pivoting instead of shifting the curve shows 6 , The pivoting takes place here around the point which is given at an extreme value Bmin of the operating state. At this value the energy requirement is urgent, so that a store must take place in any case. Starting from this value, the curves for SF with different gradients, depending on the specification K1 . K2 or K3 , Of course, the approaches of the 5 and 6 can also be combined. In addition, the influences of B and K be swapped in the curves as well. Similarly, a development is possible in which a map or a table is provided, in / the said sizes B . K and fa enter, and the / a value for the manipulated variable S and / or the threshold SF supplies.

The control unit 14 In embodiments, it is provided with a feedback interface which provides feedback to the electricity supplier and thereby compensates for the power frequency stabilizing consumption behavior, for example by discounting amounts of current taken at times above the frequency setpoint. Such feedback can be done in the usual way by radio, for example by mobile network, or even by physical disk. Alternatively or In addition, a logging electricity meter is provided (so-called smart meter), which measures and logs the respective consumption in certain time units (for example 15 min.). Based on these protocols, the utility can easily determine at which grid frequencies energy has been drawn, thereby providing compensation for grid frequency stabilizing and ultimately environmentally friendly behavior.

7 shows an embodiment for determining the value B for the operating parameter, here in the form of the stored amount of energy due to the charging current I was fed. 7 shows in an upper curve the time course of the charging current I which is always emitted when a threshold value SF for the mains frequency falls below. In these phases will be with that for the electric vehicle 4 maximum possible charging current I-ch-max loaded. There are charging pulses 30 , At times when the actual grid frequency fa below the selected threshold SF lies, there are gaps 32 in the charging process. The interval T-ch-min refers to the charging time, the constant current with I-ch-max would be expected to achieve a desired state of charge due to the Ausgangsladezustandes. This would correspond to the maximum comfort value. The comfort value K is set, for example, to a doubling of this technically minimal charging time. The charger 14 adds or integrates the charging current I over time and logs the amount of energy stored thereby E-ch , This is in the lower illustration of 4 shown the stored energy amount E-ch as a function of time t shows. At the beginning of the charging process ts the stored energy amount E-ch is inevitably zero. Every time a charge pulse 30 is discharged, the curve rises 34 in a ramp 38 , During the gaps 32 does not change the stored amount of energy E-ch; the curve 34 has a plateau 40 , It is easy to see that the ramps 38 due to the fact that the charging pulses 30 all with the same charging current I-ch-max be discharged, have the same slope. With varying peak charging current, the ramps would be 38 inclined or there are gradients with a different form than ramp shape.

At a time tp puts the control unit 14 determined that the amount of energy stored so far E-tp of the desired amount of energy E-ch-max by a difference value dE deviates, which can only be achieved if from now on with constant I-ch-max is loaded. At the time tp Therefore, it is switched to a constant continuous charge, so that it can be ensured that after 2 * T-ch-min ≤ T-ch-max the charging process is completed with the desired result. This can be achieved by the manipulated variable S from the time tp until the time te constant to a value 1 is set. This can also be achieved by setting the threshold SF is set to a value lower than the minimum frequency guaranteed by the utility. In this way, the continuous current with the charging current automatically I-ch-max reached.

The determination of the value I-ch-max is for the charging technology of motor vehicles 4 The person skilled in the art, for example, shares the electric vehicle 4 over the charging cable 18 the maximum permissible charging current with.

The basis of the 7 described embodiment relates the operating parameters on the amount of energy actually stored and takes into account the amount of energy to be stored. In other words, the value E-ch-max is known. It may, for example, from a degree of charge at the beginning of charging, that is to ts, a desired charge level at the end of charging and a battery capacity of the electric vehicle 4 be calculated. However, there are also cases in which the charge level and / or the battery capacity is not known. In such cases, the method may in another embodiment, the 8th shows to be executed. Instead of the amount of energy E-ch occurs a duty cycle V that is to be achieved. The current duty cycle V is calculated by the cumulative time the charging current was given, divided by the total charging time that was covered. The duty cycle to be achieved results from the comfort value, in the exemplary embodiment of a multiplicative factor, which is assigned to the comfort value. For example, this multiplicative factor increases from 1, which corresponds to the highest comfort value and thus the minimum charging time. At a comfort level of 1, the duty cycle must be between charge pulses 30 and gaps 32 One, ie there are no gaps 30 , The curve 42 the 8th shows how the current duty cycle develops over a certain considered interval T-int. With every charge pulse 30 , the current duty cycle increases in a ramp 44 on. During the gaps 32 it remains on a plateau 46 , The loading process is now carried out so that within the time interval T-int a desired duty cycle is achieved, which results from the comfort value.

If the comfort value specifies a multiplicative factor n in relation to the minimum charging duration, the desired duty cycle of 0.5 results, for example, for a comfort value to which the multiplication factor n = 2 is assigned. This case is in 8th shown as an example. At a time tp, the achieved duty cycle V-tp is below 0.5 and the remaining time remaining until the end of the interval T-int is the difference dV between the current duty cycle V-tp and the target value of 0, 5 can only be bridged when constant with the maximum possible charging current I-ch-max is loaded. It happens therefore at the time tp the same thing at the same time in the embodiment of the 6 took place. The car 4 is constantly charged with the maximum current. In contrast to the embodiment of 7 denotes the interval T-int but not the entire charging time, but is shorter than the entire charging time. When the time tp is in an interval depends on the course of the actual grid frequency and the threshold value. If one sets the threshold equal to or slightly larger than the frequency setpoint, it may well happen that the time tp does not occur, because the charging pulses 30 sufficient to achieve the desired duty cycle. In this case, starting in a first variant tp loading for the remaining duration of the interval T-int be exposed when the desired duty cycle has already been achieved. Charging accelerates a second variant, in which an interval at tp is aborted prematurely when the desired duty cycle has already been reached. It then immediately starts the next interval. In this way, the lengths of the gaps become 32 minimized during charging. Instead of waiting until a time tp is present, from which only with continuous power the desired end-of-charge result can be achieved, it is equally possible to make the threshold for the grid frequency depending on the difference between the desired final charge result and the current state and the elapsed time. For example, in the construction of the 8th with increasing difference, which sets within T-int of the desired duty cycle, the threshold will be lowered. In this way it is ensured that within a time interval of the length T-int the desired average duty cycle is achieved as far as possible without having to make a continuous charge towards the end of the interval. It repeats several intervals T-int , ie the length of the interval is usually chosen smaller than the expected minimum charging time. For these assumptions about battery capacity and state of charge can be made. For example, a minimum battery capacity may be used, which is the lower limit of the range for which the charger is specified. Preferred is T-int only a fraction, such as 1/2, 1/3, 1/4, 1/5 or 1/10 of a charge time under optimal conditions (actual battery capacity at the bottom of the range for which the charger 2 specified). For example T-int 15 minutes. or shorter, or 10 min. or shorter, or max. 5 min. During loading, intervals of length are repeated T-int within which care is taken to achieve the desired duty cycle, which resulted from the comfort value. In this way, the actual grid frequency may be at least in part of each interval of length T-int Be considered.

Which of the two approaches is more favorable also depends on the length of the time interval T-int from. If you choose it briefly, for example five minutes, the approach can be more favorable with the determination of the time tp. If one chooses it longer, the variation of the threshold value of the network frequency can provide the network-related behavior overall.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009041726 A1 [0004]
• DE 102011122656 A1 [0004]

Cited non-patent literature

• S. Williams et al., "Evaluating the role of building thermal inertia for the provision of decentralized demand-side primary electrical frequency regulation services", Conference Paper, June 2017, Conference: Sustainable Thermal Energy Management International Conference (SusTEM2017) [0004]
• S. Wang and T. Rui, "Supply-based feedback control strategy for air-conditioning systems for direct load control of buildings responding to urgent requests for smart grids", DOI: 10.1016 / j.apenergy.2016.10.067 [0004]

Claims (10)

A method of controlling the charging of an electric vehicle (4) from a charger (2) connected to an electrical AC supply network (6), wherein a current actual network frequency (F-a) of the electrical supply network (6) is detected, a comfort value (K) is specified, which relates to a permissible extension of a charging duration (T-ch-max), - During charging, a value (B) of an operating parameter is determined, which refers to a current state of charge of the electric vehicle (4), and - A from the charger (2) to the electric vehicle (4) output charging current (I-ch) depending on the actual grid frequency (F-a), the values (B) of the operating parameter and the comfort value (K) is set. Method according to Claim 1 , characterized in that depending on the comfort value (K), a threshold value (SF1-SF3) of the network frequency is set, below which the charger (2) no or a reduced charging current (I-ch) outputs. Method according to Claim 1 or 2 , characterized in that the manipulated variable (S) is generated, which specifies a switching on and off of the charging current (I-ch) and / or indicates how high the charging current (I-ch) should be. Method according to Claim 3 , characterized in that the charger (2) to a three-phase supply network (6) is connected and the manipulated variable (S) contains three components, which apply in each case for exactly one of the three phases. Method according to one of the above claims, characterized in that the operating parameter relates to the amount of energy (E-ch) supplied since the beginning of a charging process (ts), in particular in the form of an average duty cycle (V) of the duration of phases (30), where a charging current (I-ch-max) was delivered to the previous charging time. Method according to one of Claims 1 to 5 , characterized in that the value (B) of the operating parameter comprises the battery capacity, a grid connection power value and / or a state of charge. Method according to one of the above claims, characterized in that starting from a time (tp) after the beginning of the charge a maximum possible charging current (I-ch-max) is permanently emitted. Method according to Claim 7 , characterized in that during charging over a time interval (T-ch-max, T-int) the amount of energy supplied (E-ch) or a mean duty cycle (V) of the duration of phases in which a charging current was delivered to the is determined and the time (tp) depending on the amount of energy supplied (E-ch) or the duty cycle (V) is chosen so that within the comfort value (K) dependent extension of the charging time, the electric vehicle (4) to a desired Load completion state loaded, in particular fully charged. Method according to Claim 1 or any of the above claims, as far as related to Claim 1 , characterized in that the threshold value (SF) depends on a difference (dE) between an amount of energy (E-ch) supplied during the charge and a desired amount of energy (E-ch-max) or a deviation (dV) from a derived from the comfort value (K) setpoint value for a mean duty cycle (V), which is selected by the duration of phases in which a charge current (I-ch) was delivered to the previous charging time, is selected, in particular with increasing charging time is lowered , Charger (2) for charging an electric vehicle (4), the charger (2) comprising: a connection to an electrical AC supply network (6), - A discharge point (16) for charging current to the electric vehicle (4) and - A control device (14) for controlling the loading, wherein - the control device (14) has an input device for inputting a comfort value (K), which relates to a permissible extension of a maximum charging time (T-ch-max), - The control device (14) is adapted to detect the current actual network frequency (F-a), - The control device (14) is designed to detect during charging a value (B) of an operating parameter, which relates to a current state of charge of the electric vehicle (4), and - The control device (14) is formed, a charging current (I-ch), the charger (2) to the electric vehicle (4) outputs, taking into account the actual mains frequency (Fa), the value (B) of the operating parameter and to set the comfort value (K), - wherein the charger (2) is optionally configured to carry out a method according to one of the above claims.

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