TWI711243B - Charging point, charging device and charging system for the inductive charging of an energy store, and method for the inductive charging of an energy store - Google Patents

Abstract

The present invention relates to the checking of a magnetic coupling and safety-related components prior to an inductive energy transfer for charging an electrical energy store. To do this, the secondary-side oscillating circuit of an inductive energy transfer system is first short-circuited and current and voltage are then evaluated on both the primary side and the secondary side. The coupling factor and secondary-side safety functions can thus be checked simultaneously without measured values having to be exchanged between the primary side and the secondary side for this purpose.

Description

Charging station, charging device, charging system for inductive charging of energy storage, and method for inductive charging of energy storage

The present invention relates to a charging station and charging device for inductive charging of energy storage, a charging system for inductive charging of energy storage in a vehicle, and an induction for energy storage Charging method.

German patent application 10 2012 219 985 A1 discloses a device for inductive energy transfer to an electrically drivable vehicle. The device for inductive energy transfer in this document includes a first coil with a shield made of ferromagnetic material for reducing a stray magnetic field.

For the inductive charging of electrical vehicles, a primary coil is typically inserted into the floor or a charging panel placed on the floor. A secondary coil system is usually permanently installed under the floor of a carrier. The two coils thus form a transformer with a large air gap. For energy transfer, the primary coil generates a high-frequency AC magnetic field, which penetrates the secondary coil and induces a corresponding current there. In order to transfer the smallest possible reactive power through the air gap, a resonant operating system is provided in an oscillating circuit. This is by the The primary coil consists of an inductor and a resonant capacitor. The coil inductor, together with another capacitor, also forms an oscillating circuit on the secondary side. The two oscillator circuits are both designed and operated at the same resonance frequency.

For a safe and efficient energy transfer from the primary coil to the secondary coil, the two coil systems must be aligned with each other as accurately as possible. Before the start of the charging process, it must be ensured for this purpose that a proper and sufficient magnetic coupling system exists between the primary coil and the secondary coil. In addition, an inspection system must be performed at the beginning of the charging process to determine whether the necessary safety-related components are operational.

Therefore, there is a need for a charging station and a charging device for inductive charging of energy storage, which enables an inspection in an inductive charging system to be implemented in a simple manner. In particular, there is a need for a low-cost, efficient and safe inspection of a system for inductive energy transfer to charge energy storage.

According to the first point of view, the device of the present invention proposes a charging station for inductive charging of electric energy storage, which has the characteristics of independent item 1 of the scope of patent application.

Therefore, the present invention provides a charging station for inductive charging of electric energy storage, which has a primary coil, a feed-in device, a measuring device, and a release device. The feeding device is designed to apply a predetermined test voltage to the primary coil or feed a predetermined test current to the primary coil. The measuring device is designed to measure the feed current generated in one of the primary coils or the feed voltage generated in one of the primary coils. The cancellation device is designed to resolve if the measured feed current drops below the predetermined first primary threshold value or the measured feed voltage exceeds the predetermined first primary threshold value. In addition to a charging process for inductive charging.

According to another viewpoint, the present invention proposes a charging device for inductive charging of energy storage, which has the characteristics of independent item 4 of the scope of patent application.

Therefore, the present invention provides a charging device for inductive charging of energy storage, which has an oscillating circuit, a switching device, a current measuring device, and a control device. The oscillation circuit includes a secondary coil. In particular, the oscillation circuit may include a series circuit composed of the secondary coil and a resonance capacitor. The switching device has a first connection and a second connection. The switching device is further designed to electrically interconnect the two connection points of the oscillating circuit. In particular, the switching device can short-circuit its series circuit composed of a secondary coil and a resonant capacitor. The current measuring device is designed to measure an electrical test current in the secondary coil or in its oscillating circuit with the secondary coil. The control device is designed to control the switching device. In particular, the control device is designed to control the switching device only for the electrical connection or disconnection of the two connection points of the oscillation circuit. The control device is further designed to cancel the charging process for inductive charging if the test current measured in the secondary coil exceeds a predetermined secondary side threshold. The measurement of the electrical test current by the current measuring device and the release by the control device are carried out especially if the switching device has electrically interconnected the two connection points of the oscillating circuit.

According to another point of view, the present invention proposes a method for inductive charging of energy storage, which has the characteristics of independent item 9 of the scope of patent application.

Therefore, the present invention provides a method for inductive charging of an energy storage device, which has the steps of: short-circuiting an oscillating circuit with a secondary coil by a switching device; and setting a predetermined test voltage Or a predetermined test current is fed to a Primary coil. This method further includes a step of measuring a feed current generated in one of the primary coils or a feed voltage generated in one of the primary coils. The method further includes a step of measuring the test current generated in the secondary coil or in one of the oscillating circuits having the secondary coil. This method further includes a step: if the measured test current in the secondary coil exceeds a predetermined secondary side threshold and the measured feed current into the primary coil drops below one The predetermined threshold value or the measured feed-in voltage above the primary coil exceeds the predetermined first primary side threshold value, and the inductive charging is cancelled.

Advantages of the invention

The present invention is based on the concept of checking the coupling of a system for inductive energy transfer by applying a defined, time-controlled sequence when the system is activated. In particular, this sequence can be performed before energy transfer. The magnetic coupling of this system can be checked by the sequence according to the invention. Moreover, such as, for example, the short circuit of the secondary side oscillating circuit or the secondary coil, the safety shutdown function can be checked at the same time. A reproducible load in the form of an electrical short circuit is applied to the secondary side for inspection at the beginning of inductive energy transfer. The function of the secondary side short circuit as a safety feature and the magnetic coupling factor for inductive energy transfer can therefore be checked at the same time, without the need to exchange measured values between the primary side and the secondary side for this test. It is therefore possible to conduct an independent inspection system for potential faults based on the known system characteristics on both sides.

Since there is no safety-related information that must be exchanged between the primary side and the secondary side for this inspection, an unprotected and simple transmission channel is sufficient for the synchronization of the primary side and the secondary side. The moderate requirements for this transmission channel enable a low-cost implementation, and the price of the overall system is also reduced due to it.

In addition, various systems can be implemented simply and quickly with regard to protection requirements. Interactive inspection, such as, for example, secondary side shutdown through a short circuit of the secondary side oscillating circuit.

Since the necessary system components (such as measuring devices for measuring primary current and secondary current) for short circuits on the primary side and the secondary side for current or voltage feeding similarly exist, the inspection system according to the present invention It can be implemented at low cost by making few modifications to the charging station and the charging device.

According to one embodiment, the release device of this kind of charging station is designed to classify a fault based on the measured feed-in current or the measured feed-in voltage. In particular, the measured feed-in current or measured feed-in voltage can be compared with the other primary side threshold value for this purpose. In this way, it is also possible to distinguish between faults due to improper magnetic coupling and faults due to bad short-circuit effects on the secondary side. In view of the fact that a safety-related defect occurs in the event of a fault due to a bad short circuit on the secondary side and the inductive energy transfer system cannot be released, if necessary, insufficient magnetic coupling can be transmitted through the primary The alignment between the coil and the secondary coil is corrected and then corrected.

According to another embodiment, the feeding device of the charging station for inductive charging is designed to increase the current in the primary coil or the voltage across the primary coil until the voltage across the primary coil or through A pre-defined limit value of the primary coil current is reached. If the predefined limit value for voltage or current is not reached, even with a maximum predefined current or a maximum predefined voltage, a fault system can also be inferred in this situation. If necessary, the operating capability can be inspected with a relatively low current or voltage by passing a ramp to the current or voltage during the inspection.

According to another embodiment, a charging device for inductive charging of an energy storage device includes a voltage measurement device designed to measure the first connection and the switching device An electrical test voltage between the second connection. If the voltage measuring device can detect a significant voltage when the switching device is closed, the voltage is generated by the voltage induced in the secondary coil, a fault system of the safety-related switching device can be inferred from this. The control device of the charging device releases the charging process for inductive charging only if the measured test voltage drops below a predetermined limit value for the test voltage when the switching device is closed.

According to still another embodiment, the charging device includes a communication device designed to transmit a signal to the charging station if the first connection and the second connection of the switching device are electrically interconnected. In particular, what can be signaled by the communication device is that the necessary requirements for the inspection are met on the secondary side, and an inspection and (if necessary) a subsequent energy transfer for inductive charging will be performed.

According to another embodiment, the communication device of the charging device is designed to transmit the cancellation information of the charging process to the charging station if the control device has cancelled the charging process for inductive charging. In this way, the results of the secondary side inspection of the system components can also be transmitted to the primary side. If the cancellation system occurs on the primary side and the secondary side, the energy transfer system for charging an energy storage device can therefore start on the primary side.

According to yet another embodiment, the charging device includes a communication device designed to receive a signal from a charging station for the initialization of a charging process.

According to another viewpoint, the present invention proposes a charging system for inductive charging of energy storage in a vehicle, which has a charging station according to the present invention and a charging device according to the present invention. vehicle.

According to another embodiment of the method for inductive charging, the step of releasing the inductive charging is only if the voltage across the short-circuited oscillating circuit with the secondary coil drops as The inductive charging is cancelled when the voltage is lower than a predefined limit voltage.

Further embodiments and advantages of the present invention can be seen in the following description with reference to the accompanying drawings.

1‧‧‧Charging station

2‧‧‧Charging device

3‧‧‧Vehicle

10‧‧‧Disarm device

11‧‧‧Feeding device

12‧‧‧ Primary coil

13‧‧‧Current measuring device on the primary side

14‧‧‧Voltage measuring device on the primary side

15‧‧‧Communication device on the primary side

20‧‧‧Control device

21‧‧‧Switching device

22‧‧‧Secondary coil

23‧‧‧Current measuring device on the secondary side

24‧‧‧Voltage measuring device on the secondary side

25‧‧‧Secondary side communication device

26‧‧‧rectifier

27‧‧‧Battery protection circuit

28‧‧‧Energy Storage

In the drawings: FIG. 1 shows a schematic diagram of a charging system for inductive charging of an energy storage in a vehicle according to an embodiment; FIG. 2 shows a charging station and a charging system according to an embodiment The charging system of the charging device is a schematic diagram of a circuit diagram based on its type; and FIG. 3 is a diagram showing a flow chart of a method for inductive charging of an energy storage based on its type.

Figure 1 shows a schematic diagram of a charging system for inductive charging of energy storage devices. The charging system includes a charging station 1. The charging station 1 for inductive charging is essentially known. The principle of action for inductive energy transfer, and especially the control of the primary coil with a high switching frequency by a corresponding inverter, will therefore not be discussed in detail in this article. For energy transfer, the charging station 1 generates a high frequency AC magnetic field, which is coupled to a secondary coil of a charging device 2. For example, the charging device 2 may have a secondary coil installed on the floor, or any other components on the outside of the carrier 3. A voltage is therefore induced in the secondary coil of the charging device 2 by the high frequency AC field of the charging station 1. This voltage can be rectified and used to charge an electrical energy storage device, such as, for example, a traction battery for electrical vehicles.

FIG. 2 is a schematic diagram showing a circuit diagram of the charging station 1 and the charging device 2 according to an embodiment. The charging station 1 includes a primary coil 12. Can together with a capacitor C _P of the primary side series resonant circuit formed by a primary winding 12 of this system. The series oscillation circuit is fed by a feeding device 11. During the normal charging operation, the feeding device 11 supplies a high frequency voltage, and the series oscillating circuit is excited thereby. This system may involve excitation at approximately 85 Hz, for example. However, higher or lower frequencies used to excite the oscillator circuit are also possible. However, the voltage supplied by the feeding device 11 usually has a frequency tuned to the resonance frequency of the series oscillating circuit of the charging station 1. The resistor R _P shown in the figure represents the parasitic ohmic loss on the primary side.

At the beginning of an energy transfer from the charging station 1 to the charging device 2, an inspection system regarding the magnetic coupling and the necessary safety shutdown function on the secondary side is implemented. To do this, the secondary coil 22 of the charging device must first be positioned as accurately as possible in relation to the primary coil 12 of the charging station. For the charging of the traction battery of the electric vehicle 3, the electric vehicle 3 is arranged as accurately as possible on a primary coil 12 arranged on the floor or a floor panel for this purpose. If necessary, data can then be exchanged between the vehicle 3 and the charging station 1. Such data may include the following information: for example, information about expected energy demand, parameters used in the charging process, authorization information, or data on billing for the amount of energy consumed. These data can be transmitted from a communication device 25 of the charging device to a corresponding communication device 15 of the charging station, for example. In particular, any wireless transmission method such as, for example, WLAN, Bluetooth, mobile radio (GSM or the like), and infrared transmission or the like is possible.

Based charging apparatus 2 comprises in particular an oscillator circuit, which is formed out of one of the capacitor C _S is connected in series to a secondary side 22 of the secondary coil. If a magnetic field is coupled from the primary coil 12 to the secondary coil 22, an AC voltage is induced thereby, which can be rectified by a rectifier 26 at the output of the secondary side oscillating circuit. The output of the rectifier 26 is connected to an electrical energy storage 28 via a battery protection circuit 27, such as, for example, a traction battery or the like. If necessary, the charging device 2 may also include further components to control the charging current or charging voltage for charging the energy storage 28.

In order to avoid dangerous voltage rise or current at the output of the secondary side oscillating circuit in the event of a malfunction or dangerous situation, the charging device 2 includes a switching device 21. If necessary, the switching device 21 enables the safe shutdown of the secondary side oscillating circuit. For this purpose, the switching device 21 can electrically interconnect the two connection points A1 and A2 of the oscillating circuit on the secondary side and thus short-circuit them. The switching device 21 may be, for example, a semiconductor switching element, such as, for example, an IGBT or a MOSFET. However, other switching elements such as, for example, electrically controlled mechanical switching elements are similarly possible.

If the secondary coil 22 is arranged above the primary coil 12 and the inductive energy transfer system for charging the energy storage 28 is about to start, an initialization phase is implemented first, in which it is used to oscillate the secondary side The operating capability of the switching device 21 with a short circuit and the magnetic coupling between the primary coil 12 and the secondary coil 22 are checked. To do this, the switching device 21 is first closed, that is, an electrical connection is established between the first connection point A1 and the second connection point A2. For this, the switching device 21 may be controlled by the control device 20, for example. After the switching device 21 has thus been controlled to establish an electrical connection between the first connection point A1 and the second connection point A2, the control device 20 transmits a signal to the charging station 1. For example, an existing communication path between the communication device 25 on the secondary side of the charging device and the communication device 15 on the primary side of the charging station 1 can be used for this purpose. Since this is a simple message for the beginning of the initialization phase, there is no special data connection, especially Data connection without special protection is necessary.

As described above, the charging station 1 receives a signal for the start of an initialization phase via the communication device 15 on the primary side. A predetermined test voltage is applied to the system and then the primary coil 12 or primary coil 12 by the primary side of the capacitor C _P consisting of primary side oscillation circuit 11 by the feeding means. The test voltage is preferably an AC voltage that also uses the same frequency during the actual energy transfer period. In particular, the test voltage is an AC voltage in the resonance frequency range of the primary side oscillation circuit. However, the amplitude of this test voltage is usually smaller than the amplitude supplied by the feeding device during the charging process. For example, a test voltage having an amplitude or effective value of about 10 volts can be supplied by the feeding device during the initialization phase.

Although the predetermined test voltage is supplied by the feeding device 11, the current in the circuit composed of the feeding device and the primary side oscillating circuit having the primary coil 12 is measured by a primary side current measuring device 13 . The current value measured by the current measuring device 13 on the primary side can be evaluated by the releasing device 10. If the current measured by the current measuring device 13 on the primary side is quite low, that is, if the measured current on the primary side, especially the effective value of the measured current, drops below a pre-defined first threshold, you can The inference is that the magnetic coupling between the primary coil 12 and the secondary coil 22 and the short circuit on the secondary side generated by the switching device 21 are sufficiently good. In this case, the release device 10 can release the charging process and especially the inductive energy transfer from the charging station 1 to the charging device 2.

Conversely, if the current measured by the current measuring device 13 on the primary side is very high, no sufficiently high magnetic coupling system exists between the primary coil 12 and the secondary coil 22, and the release device 10 is not released for use Inductive energy transfer during the charging process. If the current measured by the current measuring device 13 on the primary side is between the threshold of the first primary side and the higher second primary side Between the threshold values, there is no sufficient magnetic coupling system or the switching device 21 in the charging device 2 has failed. Also in this case, the release device 10 can prevent the release of the inductive energy transfer from the charging station to the charging device 2. If the measured feed current is higher than the second threshold, an insufficient magnetic coupling system exists.

If the release device 10 of the charging station 1 can classify the insufficient magnetic coupling between the primary coil 12 and the secondary coil 22 based on the evaluation of the current measured by the current measuring device 13 on the primary side, a corresponding sender The signal can be displayed to the user. If necessary, the user can then readjust the carrier 3 with the secondary coil 22 so as to optimize the positioning of the secondary coil 22 relative to the primary coil 12.

As an alternative to the aforementioned feeding by a predefined test voltage of the feeding device 11, it is also possible for a predefined test current to be fed by the feeding device 11 to the primary coil 12 and An oscillating circuit composed of a capacitor C _P on the primary side. In this case, the generated feed-in voltage can be measured by a voltage measuring device 14 on the primary side. The measured feed-in voltage can be similarly supplied to the release device 10 for evaluation. For example, the releasing device 10 can control the feeding device 11 so that, for example, a pre-defined test current having an effective value of about 1 ampere is fed. The release device 10 can evaluate the feed-in voltage determined by the voltage measuring device 14 on the primary side, and from this, can infer the magnetic coupling and the operating capability of the switching device in the charging device 2. If the predefined test current system has been reached by a feed voltage that is below a predefined threshold, then an insufficient magnetic coupling system exists. Conversely, if the feed-in voltage with the pre-defined test current exceeds the threshold of the first primary side, a sufficient magnetic coupling system exists and the switching device 21 in the charging device 2 can be judged to be operating . If the generated feed voltage with a predefined test current is between the threshold of the first primary side and the threshold of the second primary side, there is no sufficient magnetic coupling system or the charging device 2 The switching device 21 has a fault.

After a signal used for the beginning of an initialization phase, no further communication with the charging device 2 is required, and the aforementioned charging station 1 can therefore be implemented regarding a sufficient magnetic coupling and safety-related A check of the operating capability of the switching device 21 and then the release of the inductive energy transfer is achieved.

Similarly, after the beginning of the initialization phase, regardless of and without further communication with the charging station 1, the charging device 2 can also check the operating capability of the switching device 21 and the connection between the primary coil 12 and the secondary coil 22 The full magnetic coupling. For this purpose, a secondary-side electrical test current is measured by a secondary-side current measuring device 23 in the current path of the secondary-side oscillating circuit. The test current on the secondary side is evaluated by the control device 20. If the test current on the secondary side exceeds a pre-defined secondary side threshold, then a sufficient magnetic coupling system exists in this situation. A voltage drop across the two connections of the switching device 21 can be simultaneously measured by a voltage measuring device 24 on the secondary side. If the voltage drop across the switching device 21 exceeds a predefined limit value, no sufficiently good short-circuit system can be achieved by the switching device 21. In this case, if there is a danger, it may be a safe shutdown not by the switching device 21. If the switching device 21 is closed and the voltage drop of more than a predefined limit value is exceeded, a fault is therefore confirmed during the initialization phase.

If the failure of the switching device 21 or the insufficiently good magnetic coupling between the primary coil 12 and the secondary coil 22 is confirmed, the charging process cannot be cancelled by the control device 20. However, if a sufficiently high magnetic coupling (i.e., a current in the primary side oscillating circuit more than a predefined limit value) and at the same time across the switching device 21 is less than the predefined limit value A voltage drop is detected during the initialization phase, and the charging process of the electric energy storage 28 can be cancelled by the control device 20.

In order to ensure the safety-related parameters during the entire charging process and the inductive energy transfer period associated with it, short-circuit the oscillating circuit of the secondary side and evaluate the application of a predefined test voltage or a predefined test current on The aforementioned sequence of the current or voltage generated during the side period can be periodically repeated. For example, this sequence can be repeated periodically at predefined time intervals, for example: every 15, 30 or 60 minutes. For this purpose, a brief interruption of the inductive energy transfer by a short circuit on the secondary side of the switching device 21 and the application of a test current or a test voltage on the primary side are necessary. After the magnetic coupling and safety shutdown have been successfully checked, the inductive energy transfer system for charging the energy storage 28 can continue. For this type of inspection during the charging process, an interruption of the inductive energy transfer must first be a signal. After that, the switching device 21 can be closed on the secondary side and the inspection can be performed as described above . The synchronization of this sequence can be implemented, for example, via the communication connection between the communication devices 25 and 15 on the secondary side and the primary side or by short-circuiting the switching device 21.

As an alternative to the application of a predefined test current or a predetermined test voltage fed into the device 11 during the initialization phase, it is also possible to continuously increase the test voltage or test current and evaluate the generated voltage or current. When the pre-defined limit value is reached, the generated feed current and the generated feed voltage are determined, and the operating capability of the switching device 21 or the magnetic coupling can be deduced from this in the same manner as previously described. The continuous increase in test current or test voltage is based on safety and can be limited to a predefined limit value.

FIG. 3 is a schematic diagram showing an embodiment of the present invention as a method for inductive charging of energy storage based on its type. In step S1, there is a secondary line An oscillating circuit of the ring 22 is first short-circuited by a switching device 21. In step S2, a predetermined test voltage or a predetermined test current is then fed into the primary coil. Next, in step S3, a generated feed current is measured in the primary coil or a generated feed voltage is measured in the primary coil. In parallel with this, in step S4, a generated test current is measured in the secondary coil. Next, in step S5, if the measured test current exceeds a predetermined secondary-side threshold and the measured feed-in current falls below a predetermined primary-side threshold or the measured feed-in voltage at the same time If the system exceeds a predetermined threshold for the primary side, the inductive charging system is released. In step S5, the inductive charging system can also only be used if a voltage across the short-circuited oscillating circuit with the secondary coil 22 (ie, across the switching device 21 of the charging device 2) drops below a predefined value The limit voltage is released.

In order to take into account any time delays during the sequence of the initialization phase, the current and voltage evaluations in the charging station 1 and the charging device 2 are only after the initialization has been initiated by the charging device 2 to the charging station 1 Performed for a predetermined period of time. For example, the signaling by the charging device 2 can be followed by a 2-second wait until the required system state is set and the check is performed.

The initialization phase can be further carried out by sending a signal from one of the communication device 15 on the primary side of the charging station to the communication device 25 on the secondary side of the charging device. If the communication device 25 on the secondary side receives a corresponding signal for initialization, the aforementioned sequence of short-circuiting the secondary coil 22 and evaluating current and voltage can be followed.

In summary, the present invention relates to the inspection of a magnetic coupling and safety-related components prior to inductive energy transfer for charging an electrical energy storage. For this purpose, the oscillating circuit on the secondary side of an inductive energy transfer system is short-circuited first, and the current and voltage are Then evaluate on the primary and secondary sides. The coupling factor and the safety function of the secondary side can therefore be checked simultaneously, and the measured value does not need to be exchanged between the primary side and the secondary side for this purpose.

10‧‧‧Disarm device

11‧‧‧Feeding device

12‧‧‧ Primary coil

15‧‧‧Communication device on the primary side

20‧‧‧Control device

21‧‧‧Switching device

22‧‧‧Secondary coil

25‧‧‧Secondary side communication device

26‧‧‧rectifier

27‧‧‧Battery protection circuit

28‧‧‧Energy Storage

Claims (10)

A charging station (1) for inductive charging of an electric energy storage (28), which includes: a primary coil (12); a feeding device (11), which is designed to feed a predetermined test voltage or a predetermined test current Into the primary coil (12); measuring devices (13, 14), which are designed to measure the feed current generated in the primary coil or the feed voltage generated in the primary coil; and the release device (10) It is designed to cancel the charging process for the inductive charging if the measured feed-in voltage exceeds the predetermined primary side threshold. For example, the charging station (1) of item 1 in the scope of the patent application, wherein the release device is designed to classify the fault based on the measured feeding current or the measured feeding voltage. For example, the charging station (1) of item 1 or 2 of the scope of patent application, wherein the feeding device (11) is designed to continuously increase the current in the primary coil (12) or the voltage across the primary coil (12) , Until the predefined limit value for the voltage across the primary coil (12) or the current through the primary coil (12) is reached. A charging device (2) for inductive charging of an energy storage (28), comprising: an oscillating circuit with a secondary coil (22); a switching device (21), which is designed to electrically interconnect the oscillation Two connection points (A1, A2) of the circuit; voltage measuring device (24), which is designed to measure the electrical test voltage between the first connection point (A1) and the second connection point (A2) of the oscillation circuit ; And a control device (20), which is designed to control the switching device (21), only if the measured electrical test voltage across the secondary coil is lower than when the switching device (21) is closed The electricity When the gas test voltage has a predefined limit value, the charging process for the inductive charging is cancelled. For example, the charging device (2) of item 4 of the scope of patent application further includes a communication device (25), and the communication device (25) is designed so that if the first connection point (A1) of the oscillation circuit is connected to the second connection When point (A2) is electrical interconnection, the signal is sent to the charging station (1). For example, the charging device (2) of item 5 of the scope of patent application, wherein the communication device (25) is further designed so that if the control device (20) has cancelled the charging process for inductive charging, the charging process will be The release information is sent to the charging station (1). For example, the charging device (2) of item 5 of the scope of patent application, wherein the communication device (25) is further designed to receive the signal from the charging station (1) for the initialization of the charging process. A charging system for inductive charging of an energy storage (28) in a vehicle (3), which includes: a charging station (1) for one of items 1 to 3 in the scope of the patent application; and A device (3), which has a charging device (2) as one of items 4 to 6 in the scope of the patent application. A method for inductive charging of an energy storage device (28), which includes the steps: in step S1, a switching device (21) is used to short-circuit an oscillating circuit with a secondary coil (22); in step S2, Feed a predetermined test voltage or a predetermined test current to the primary coil (12); in step S3, measure the feed current generated in the primary coil (12) or the feed voltage generated on the primary coil (12); In step S4, measure the test current generated in the secondary coil (22); in step S5, if the measured test current exceeds a predetermined secondary side threshold and the measured feed voltage exceeds a predetermined When the primary side threshold is reached, the inductive charging is cancelled. Such as the method of item 9 of the scope of patent application, wherein the step S5 of releasing the inductive charging is only when the voltage across the short-circuited oscillating circuit with the secondary coil (22) drops below the predefined limit voltage, Then the inductive charging is cancelled.

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