DE102013215785B4 - Vehicle-side charging module, inductive charging system and method for inductively charging an energy storage device - Google Patents

Abstract

A vehicle-side charging module for inductively charging an energy store (140) of a motor vehicle with an inductive energy transfer device (120) is described. The charging module (131) comprises (a) a power line (206) extending between an input and an output of the charging module (131), (b) an electrical measuring device associated with the power line (206) for measuring an electrical charging quantity, ( c) an evaluation unit (230) coupled to the electrical measuring device for generating a trigger signal, if the measured electrical quantity exceeds a predetermined limit in a comparison; and (d) a safety device coupled to the evaluation unit (230) for receiving the triggering signal and for reducing power when the triggering signal occurs. Furthermore, an inductive charging system for charging an energy store (140) of an electromobile motor vehicle is described, which has a charging system with such a charging module (131), and a method for inductive charging.

Description

The invention generally relates to the technical field of electromobile motor vehicles having an electrical energy storage which must be charged from time to time. The invention relates to a vehicle-side charging module for inductively charging an energy storage device of an electromobile motor vehicle using an inductive energy transfer device. The invention further relates to an inductive charging system for charging an energy store of an electromobile motor vehicle. Furthermore, the invention relates to a method for inductively charging an energy storage device of an electromobile motor vehicle using an inductive energy transfer device.

The energy storage of electric cars and plug-in hybrid vehicles are usually charged on a power grid. A convenient option is the so-called inductive charging dar. This power is provided from the power grid. After appropriate rectification and stabilization, the power provided is transmitted wirelessly by means of an inductive transmission device into a high-voltage architecture of the electric vehicle. Typically, inductive energy transfer has the advantages of being a robust and convenient energy transfer compared to other energy transfer methods, such as conductive charging or wired charging.

Inductive power transmission devices for vehicles are usually operated with transmission frequencies between 20 kHz and 200 kHz. Thus, the power can be supplied to the downstream charger, which can be operated, for example, at frequencies up to 60 Hz, or the energy storage can be supplied, which accepts, for example, only DC power and / or voltage must be rectified.

The coupling factor of a primary coil providing energy and a secondary coil receiving the energy of the inductive energy transmission device is subject to fluctuations and possible errors. One possible cause of fluctuations is, for example, the spacing of the coils or the orientation of the coils relative to one another. As the coupling factor decreases, the efficiency of the energy transfer and thus the voltage to be rectified in the charging system generally also decreases.

It is also conceivable that the primary coil of the inductive energy transmission due to "misunderstandings" or misconduct provides too much or too little power. In the case of power transmission that is too low, the energy storage of the vehicle will not be charged and charging will be aborted if necessary. In the case of an excessively high power transmission, undesirably high voltages can occur at the components of the charging system or the current carrying capacity of the components can be overloaded. As a result, the components downstream of the energy transmission device, for example rectifier module, charger or the energy store, can be irreversibly damaged.

Safety systems are known in which the vehicle communicates with the energy transmission device and can transmit information relating to the power requirements of the charging system. This solution is not fundamentally trouble-free and has the disadvantage that large amounts of data can arise, which must be transmitted. In the transmission, there are delays, so that can not be intervened in time via a communication interface to avert damage to the vehicle.

Simple overvoltage mechanisms have the disadvantage that they have to be installed and carried separately and represent an additional cost factor.

The publication US 2013/057082 A1 describes a non-contact power transmission system in which motor-driven capacitors detune a resonant circuit in the power transmission path. The detuning of the receiving circuit leads to a reduction in the transmitted power, so as to avoid damage in the event of a fault. However, engagement in the power reduction circuit depends on the function of the motor and on the mobility of the tunable capacitor shaft.

The invention has for its object to improve the safety when inductive charging an electric car.

This object is solved by the subject matters of the independent claims. Advantageous embodiments, further features and details of the present invention will become apparent from the dependent claims, the description and the drawings. In this case, features and details that are described in connection with the loading module, of course, also in connection with the method and the charging system, and vice versa, so that with respect to the disclosure of this invention to the individual aspects of the invention always reciprocal reference can be made.

According to a first aspect of the invention, a vehicle-side charging module for inductively charging an energy store of an electromobile motor vehicle using an inductive energy transfer device is described. The vehicle-side charging module has (a) a power line which extends between an input and an output of the charging module, (b) an electrical measuring device which is assigned to the power line and which is set up for measuring an electrical variable of a charging process of the energy store, c) an evaluation unit which is coupled to the electrical measuring device and which is set up to (i) compare the measured electrical variable with a predetermined limit value and (ii) if the measured electrical variable exceeds the predetermined limit value, generate a triggering signal, and (d) a safety device which is coupled to the evaluation unit and which is configured to (i) receive the generated readout signal and (ii) to effect a power reduction of the charging process in response to the reception of the triggering signal.

The invention is based on the finding that the safety of inductive charging of the energy store can be improved by detecting undesirably high currents and voltages during the charging process by means of the measuring device and the evaluation unit in the case of undesirably high measured values of current and / or voltage, the trigger signal can generate. In response to the trigger signal, the safety device immediately causes a reduction in the charging process.

In particular, the electrical measuring device can detect how high the voltage and / or the current that occur during the charging process of the energy storage. For example, in the case of an unfavorable alignment of the energy-transmitting primary coil relative to the energy-receiving secondary coil, an undesirably high power transmission can take place, which is found in particular in undesirably high current intensities and voltage levels in the downstream charging module. By means of the electrical measuring device, the value of the current intensity and / or the voltage level can be measured and then fed to the evaluation unit. In the evaluation unit, a comparison of the measured value with the predetermined limit value can be made. In the event that the measured value exceeds the predetermined limit value, the evaluation unit can generate the trigger signal and send it to the safety device. In response to the reception of the triggering signal, the safety device may take protective measures that reduce the current intensity and / or voltage level of the charging process; in particular, the safety device may bring about a termination of the charging process.

According to a further aspect of the invention, an inductive charging system for charging an energy store of an electromobile motor vehicle is described. The inductive charging system comprises (a) a primary coil coupled to a power feed system, (b) a secondary coil configured to inductively receive power from the primary coil, (c) a vehicle-side charging module of the type described above Secondary coil is coupled, and (d) an energy storage, which is coupled to the vehicle-side charging module.

In particular, the primary coil may be installed in the floor of a parking lot and inductively send energy to the secondary coil in the vehicle. The transmitted energy can be supplied to the energy storage device by means of the vehicle-side charging module.

According to a further aspect of the invention, a method is described for inductively charging an energy store of an electromobile motor vehicle using an inductive energy transfer device. The described method comprises (a) measuring, by means of a measuring device, an electrical quantity of a charging process of the energy store in a power line which connects the inductive energy transfer device with the energy store, (b) comparing the measured electrical size of the charging process with a predetermined limit value by means of a (c) generating a trigger signal if the measured electrical quantity exceeds the predetermined limit, (d) receiving the generated trigger signal from a safety device, and (e) reducing a power of the charging by the safety device in response to receiving the triggering signal. Reducing power, in particular, serves as an emergency power reduction to avoid damage due to overload, but may also be performed as part of a control process.

The described method is also based on the finding that the safety of the inductive charging of the energy store can be improved by detecting undesirably high currents and voltages during the charging process by means of the measuring device and the evaluation unit in the case of undesirably high measured values of current and / or voltage can generate the trigger signal. In response to the trigger signal, the safety device immediately causes a reduction in the charging process. The term "charge module" can be understood as a circuit which is connected downstream of the inductive energy transfer and can modulate energy into a form suitable for the downstream energy store. By way of example, the charging module can modulate a high-frequency signal transmitted via an inductive transmission link into a direct current which is suitable for being transmitted to the energy store of an electromobile.

The term "energy storage" can be understood to mean a rechargeable storage of electrical energy, in particular a rechargeable battery or accumulator, which can serve as a source of energy for a motor vehicle with an electric motor.

The term "inductive energy transmission device" can be understood as a device for the non-contact transmission of energy. In this case, the energy can be transmitted by means of the transformer principle over distances of, for example, up to about 25 cm. By means of the current-carrying primary coil, a time-varying magnetic field is generated. The corresponding secondary coil is traversed by at least part of the magnetic field and thereby induces a current flow in the secondary coil. For example, the primary coil may be integrated in the floor of a parking space, the secondary coil may be located in the underbody of the motor vehicle. If the motor vehicle with the secondary coil is parked in the parking lot with the primary coil, it is possible to inductively transfer energy between the primary and secondary coil and thus charge the vehicle's energy store.

The term "electrical measuring device" can be understood to mean a device which can detect the value of an electrical quantity, for example a current intensity, a voltage level or a non-electrical quantity, such as the temperature.

The term "evaluation unit" can be understood to mean a component, for example a microcontroller, which can receive measured values and can output a signal based on the received values. In particular, the evaluation unit can receive measured values that are indicative of a voltage or a current during the charging process and, in the case of increased voltage or current measured values, output the triggering signal to the safety device, which causes a reduction of the corresponding current and voltage values.

The "predetermined limit value" can be understood in particular to be the value of the current and / or the voltage in the charging system, up to which the charging process is possible without danger. If the limit value is exceeded, current and / or voltage are increased in such a way that damage to the components can result.

The term "triggering signal" can in particular be understood to mean an information signal which is generated by the evaluation unit in response to undesirably increased voltage and current measured values during the charging process. For example, it may have a "distress signal", which is sent to the safety device to effect a power reduction or a termination of the power transmission there. In particular, the trigger signal may comprise a plurality of sub-signals that may be sent to a plurality of actuators.

The term "safety device" can be understood to mean a device which can take measures to maintain and / or restore a safe state, for example in the charging module. In particular, after receipt of the triggering signal of the evaluation unit, the safety device can in response switch on or bypass resistors, detune coils and / or take further regulating measures to reduce currents and / or voltages to a desired level or to completely abort a charging process for safety reasons. Furthermore, this term is understood to mean a power control unit, current control unit, power control unit or current control unit which determines the amount of power, of the current or, in general, of the energy which is transmitted to the energy store. This power control unit, power control unit, power control unit, or current control unit is configured as described herein to reduce said amount upon receipt of the trip signal, such as until the electrical variable is within a threshold or within a threshold interval. In the case of a control unit, a regulation of the amount is provided with the value as the actual value, with a predetermined desired value and with the control objective to minimize the difference between the actual value and the desired value, whereby the amount is changed as a manipulated variable, in particular as described here ( in the sense of the power reduction described here). Since the protection according to the invention from overload is also realized by these control and regulating operations, such a power control unit, current control unit, power control unit or current control unit is described as a safety device.

The term "power reduction" can be understood as a reduction of the current intensity and / or the voltage level of the charging process. In particular, this can be understood as a complete interruption of the energy transfer and thus of the charging process, or even a Reduction to an amount below a threshold or to a value within a threshold interval. This power reduction can be carried out, in particular, in the context of a power control method or a power control method, which in particular comprises at least one step of the method described here.

The provision of the charging module can have the advantage that the components involved in the charging process, for example rectifier, charger and energy storage, are protected against damage by excessively high voltages and currents through rapid intervention of the safety device, without manual intervention in the charging process being necessary , Another advantage may be that the safety device already has existing components, such as resistors, and therefore no additional equipment expense is required. In addition, the charging module offers protection against touching for workshop personnel, even if the charging module is open. Another advantage of the charging module can be seen as assisting in diagnosing faulty power transfer.

According to one exemplary embodiment of the invention, the measuring device has a current sensor and the electrical variable is a current intensity of a charging current for the energy store through the power line.

The current sensor may in particular have a low-impedance measuring resistor in the power line of the charging module. The low-impedance measuring resistor can z. B. have a resistance of 0.01 mΩ to 1.0 mΩ. At the measuring resistor then a voltage drop takes place, which can be measured by means of tapping points in front of and behind the measuring resistor. The measured value is indicative of a current intensity in the power line and can be fed to the evaluation unit, which can then initiate a power reduction of the charging process, if the measured value exceeds a predetermined limit value. In addition, a communication module coupled to the evaluation unit can reduce the power transmission on the side of the primary coil.

According to a further embodiment, the measuring device has a voltage sensor and the electrical variable is a voltage level of a charging voltage for the energy store, which is applied to the power line.

In particular, the voltage sensor can have a voltage divider which has two series-connected electrical resistors. By means of a tapping point between the two resistors, a partial voltage can be measured, which is indicative of the voltage in the charging module. The measured value can be fed to the evaluation unit, which then initiates a power reduction of the charging process if the measured value exceeds a predetermined limit value. In addition, a communication module coupled to the evaluation unit can reduce the power transmission on the side of the primary coil.

According to a further exemplary embodiment, the safety device (i) has a precharging resistor in the power line and (ii) an electrical bridge bridging the precharging resistor with a first switching element, wherein in a first switching state of the first switching element the precharging resistor is bridged by means of the electrical bridge and the first switching element is arranged to interrupt the bridge in response to a first sub-signal of the triggering signal.

The precharge resistor can in particular limit the current which precharges a capacitor when the charging process is activated. This precharge can serve to protect the components by preventing sparking. If the components are precharged, the precharge resistance can be bridged for operation by the first switching element assuming a second switching state in which the precharge resistor is bridged.

In addition, the precharge resistor can be switched on in the event of an undesired voltage increase. For example, in the case of an undesired voltage increase in response to the receipt of the first partial signal of the triggering signal, the first switching element can be switched from the first switching state to the second switching state, whereby the electrical bridge is interrupted or the precharging resistor is switched into the power line, thereby reducing the power the charging process contributes.

The provision of the precharge resistor may have the advantage that undesirably high voltages and undesirably high currents can be rapidly reduced without requiring manual intervention in the charging process. In addition, the same components can serve both the pre-charging of the components and the power reduction in case of unwanted voltage increase. Due to the redundant use of the precharge resistor can be dispensed with additional safety components with the same function, whereby the loading module can be realized space and reduced weight.

According to a further embodiment, the safety device has a shunt line with (i) a discharge resistor and (ii) a second switching element, wherein in a first switching state of the second switching element, the bypass line is interrupted and wherein the second switching element is arranged to close in response to a second partial signal of the trigger signal, the shunt line.

In particular, the second switching element can switch to the second switching state in response to the reception of the second partial signal of the trigger signal, whereby the bypass line is closed with the discharge resistor. As a result, the connected discharge resistor contributes to the power reduction of the charging process.

In addition, in the case of a separation of the charging module from the high-voltage network, the same discharge resistor can be connected in order to discharge the output voltage of the charging module.

The closing of the shunt line by means of the second switching element at undesirably increased voltages may in particular have the advantage that the output voltage of the charging module is safely discharged. A further advantage can be seen in the fact that resonant circuits located in the charging system, for example an input-side resonant circuit, are loaded, which would run free without switching on the discharge resistor. Due to the redundant use of the discharge resistor to reduce voltage at undesirably increased voltage and a separation of the charging module from the high-voltage network can be dispensed with additional safety components with the same function, whereby the loading module can be realized space and weight reduced.

According to a further exemplary embodiment, the safety device has a tapping line with a third switching element, wherein an input-side end of the tapping line is electrically connectable to a tapping point of a secondary coil or a compensation capacitor of the inductive energy transmission device and wherein in response to a third partial signal of the triggering signal an electrical resonance circuit, which includes the secondary coil and the compensation capacitor is tunable.

In particular, in the case of an undesirably high voltage during the charging process, the third switching element can assume a switching state in response to the reception of the third partial signal of the trigger signal, in which case the secondary coil is partially bridged. The bridging can lead to an intentional detuning of the secondary coil, which results in a deviation from the resonance of the secondary coil and thus a voltage reduction. Alternatively or in combination, in addition, a capacitor in the input-side resonant circuit may be tunable. Furthermore, the input-side resonant circuit may have a plurality of capacitors, which are tunable individually or jointly. The provision of multiple coils is possible. In these cases, the third switching element can be duplicated to detune the coils and capacitors individually.

• – Zuschalten zumindest eines Kondensators und/oder einer Induktivität zu dem Resonanzkreis, entweder seriell oder parallel;
• – Überbrücken eines zusätzlichen (Serien-)Kondensators und/oder einer zusätzlichen (Serien-)Induktivität innerhalb des Resonanzkreises
• – Abtrennen eines zusätzlichen (Parallel-)Kondensators und/oder einer zusätzlichen (Parallel-)Induktivität innerhalb des Resonanzkreises und/oder
• – Ändern eines Induktivitätswerts einer Induktivität oder eines Kapazitätswerts einer Kapazität innerhalb des Resonanzkreises durch Verschieben eines Dielektrikums oder zumindest einer Elektrode des Kondensators oder durch Verschieben eines Kerns relativ zu einer Wicklung der Induktivität bzw. einer Wicklung relativ zum Kern der Induktivität. (Es kann auch zum Zwecke des Verstimmens der Abstand zwischen einem zusätzlichen magnetischen Material (paramagnetisch oder ferromagnetisch) und mindestens einer der Induktivitäten des Resonanzkreises verändert werden. Das Material kann dem Material des Kerns entsprechen.)

The detuning may include:

• - connecting at least one capacitor and / or an inductance to the resonant circuit, either serially or in parallel;
• - Bridging an additional (series) capacitor and / or an additional (series) inductance within the resonant circuit
• - Separating an additional (parallel) capacitor and / or an additional (parallel) inductance within the resonant circuit and / or
• - Changing an inductance value of an inductance or a capacitance value of a capacitance within the resonant circuit by shifting a dielectric or at least one electrode of the capacitor or by shifting a core relative to a winding of the inductance or a winding relative to the core of the inductance. (Also, for detuning purposes, the distance between an additional magnetic material (paramagnetic or ferromagnetic) and at least one of the inductances of the resonant circuit may be varied.) The material may correspond to the material of the core.)

As a capacitor or inductor of the resonant circuit capacitors or inductors are referred to, which are provided in the input-side resonant circuit (primary resonant circuit) or in the vehicle-side resonant circuit (secondary resonant circuit). The capacitor or the inductance have an influence on the resonant frequency of the relevant resonant circuit.

While the first three of the above-mentioned possibilities of detuning relate to an electrical / electronic change in an impedance of the resonant circuit, the fourth of the aforementioned possibilities relates to a mechanical change in an impedance of the resonant circuit. The detuning provides that at least one impedance, the imaginary part of an impedance (ie, an inductive or capacitive reactance) is changed. In other words, detuning is provided by changing the resonant frequency of the resonant circuit (ie, the secondary or primary coil), particularly by increasing the difference between the resonant frequency of the primary coil and the resonant frequency of the secondary coil. For resonant circuits higher Goodness can be generated by a very slight detuning a strong change in performance.

In particular, one or more capacitors may be located in the power line and / or in shunt lines, which may be associated with one or more tunable resonant circuits.

The advantage of tunable resonant circuits is, in particular, that undesirably high voltages and undesirably high currents can be rapidly reduced without requiring manual intervention in the charging process. A further advantage can be seen in that existing components, for example the secondary coil, which is part of the inductive energy transmission device, can contribute redundantly to the voltage reduction in the charging module. Thus, the charging system can be realized space and weight reduced.

According to a further embodiment, the vehicle-side charging module further comprises a part of a Überwachungsleitungssytems, which is electrically connected by means of plug connections with another part of the monitoring line system. In this case, a first plug connection of the plug connections of the inductive energy transmission device is assigned. A second plug-in connection of the plug connections is assigned to the energy store.

In particular, current or an alternating signal can be fed into the monitoring line at an input of the monitoring line. In the event that the first plug-in connection and the second plug-in connection are plugged in, the current can flow through the monitoring line system and be detected at an output of the monitoring line. In the alternative case that at least one of the plug-in connections is not plugged in, for example because the charging module has been removed from the charging system, the monitoring line is interrupted and the fed-in current can not be detected at the output of the monitoring line. In the case of an interrupted monitoring line, the inductive charging process can be aborted.

The provision of a monitoring line system in the charging module can in particular have the advantage that it can be detected by simple means whether the charging module is located in the charging system and, if appropriate, the inductive charging process can be interrupted.

According to a further exemplary embodiment, the evaluation unit is set up to receive a measured value from a magnetic field sensor and to effect the power reduction of the charging process in response to the reception of the measured value.

In particular, at least one magnetic field sensor can be located on the vehicle floor, which can measure the field strength of the primary coil and can send the result to the evaluation unit. In the case of too high a field strength, the evaluation unit can send the triggering signal to the safety device, whereby a power reduction of the charging process is initiated.

The provision of magnetic field sensors can in particular have the advantage that a diagnosis of faulty energy provision on the side of the primary coil is possible.

According to a further embodiment, the vehicle-side charging module further comprises a rectifier for rectifying an AC power signal provided by the inductive power transmission device.

In particular, a rectifier may be located in the power line, which connects the inductive energy transfer device with the energy storage.

In accordance with a further exemplary embodiment, the evaluation unit is set up to send the triggering signal to a power supply system connected upstream of the inductive power transmission device in order to effect a reduction in the power of the charging process.

In particular, the evaluation unit can be coupled to a communication module. With an undesirably high power transmission, the communication module can send a signal to the primary-side power supply system.

The term "power supply system" can be understood as a power electronics connected to the power supply network, which has, for example, a drive unit which is superordinate to the primary-side rectifier module and the primary coil of the inductive energy transmission device coupled thereto.

According to one embodiment, reducing the power of the charging process has an interruption of the charging process.

In particular, when too high voltages, currents or temperatures occur, the charging process can be completely interrupted in order to avoid damage to the components.

It should be noted that embodiments of the invention have been described with reference to different subject matters. In particular, some embodiments of the invention are described with apparatus claims and other embodiments of the invention with method claims. However, it will be readily apparent to those skilled in the art upon reading this application that, unless explicitly stated otherwise, in addition to a combination of features belonging to a type of subject matter, any combination of features that may result in different types of features is also possible Subject matters belong.

Further advantages and features of the present invention will become apparent from the following exemplary description of presently preferred embodiments. The individual figures of the drawing of this application are merely to be regarded as schematic and not to scale.

1 shows a schematic representation of an inductive charging device.

2 shows a schematic representation of the vehicle-side loading module

3 shows a schematic representation of the vehicle-side loading module

It should be noted that features of different embodiments, which are the same or at least functionally identical to the corresponding features or components of the embodiment, are provided with the same reference numerals or with other reference numerals, which are only in their first digit of the reference number of a (functionally) corresponding feature or a (functional) corresponding component. In order to avoid unnecessary repetitions, features or components already explained on the basis of a previously described embodiment will not be explained in detail later.

It should also be noted that the embodiments described below represent only a limited selection of possible embodiments of the invention. In particular, it is possible to suitably combine the features of individual embodiments with one another, so that a multiplicity of different embodiments are to be regarded as obviously disclosed to the person skilled in the art with the embodiment variants explicitly illustrated here.

1 shows a schematic representation of an inductive charging device 100 , From the power grid is a 3-phase voltage 150 won. After rectification and conversion by means of a primary-side rectifier module 110 becomes a pulse width modulated high frequency energy 151 to an inductive energy transfer device 120 transfer. Here, the energy becomes inductive from a primary coil 121 to a secondary coil 122 transfer. Subsequently, the high-frequency energy 152 in a vehicle-side module 130 transfer. Here takes place by means of the vehicle-side charging module 131 a rectification takes place. After stabilization, a corresponding direct current 153 to the energy storage 140 transfer.

2 shows a schematic representation of the vehicle-side loading module 131 in which by means of a rectifier 205 in a power line 206 a rectification of the charging current takes place. The secondary coil 122 is part of the inductive energy transfer device.

By means of a measuring resistor 220 , where a voltage drop occurs, finds a current measurement 280 instead, the result is sent to an evaluation unit 230 is transmitted. By means of a voltage divider 260 finds a voltage measurement 270 instead, the result to the evaluation unit 230 is transmitted. Are they at the evaluation unit 230 received measured values of the current and / or the voltage undesirably high, so sends the evaluation 230 a trigger signal, which may consist of a plurality of sub-signals. The sub-signals can at the switching elements 201 . 202 . 203 . 204 be received. A circuit control of the elements 201 . 202 . 203 and 204 is not explicitly shown here for reasons of clarity. The first switching element 201 bridges a precharge resistor in response to receiving a first sub-signal 240 , which causes a performance reduction of the charging process. The second switching element 202 In response to the receipt of a second sub-signal, a shunt line with a discharge resistor is switched 250 to, which causes a performance reduction of the charging process. The third switching element 203 detunes the coil in response to receiving a third sub-signal 122 and thus an input-side resonant circuit, which is a capacitor 210 assigned. The detuning effects a performance reduction of the charging process. The fourth switching element 204 opens the input side resonant circuit in response to receiving a fourth sub-signal. In addition, the evaluation unit 230 with undesirably high current and / or voltage values a message to a communication module 290 which causes a power reduction on the power feeding side.

In the event that the currents and voltages in the charging process in the normal range, so no security measures are required, a combination of switching states, for example, as follows: (i) The first switching element 201 is switched to a closed state, so that the precharge resistance 240 is bridged. There is no voltage drop on the pre-charge resistor 240 instead of. (ii) The second switching element 202 is switched to an open state, so that the shunt line with the discharge resistor 250 not closed. The discharge resistance 250 does not contribute to reducing voltages and currents. (iii) The third switching element 203 is switched to an open state so that the secondary coil 122 or the resonant circuit is not detuned. The secondary coil is not detuned and the coupling between the primary coil and the secondary coil is not reduced, so that there is no power reduction of the charging process.

In the event that the voltages and / or currents are undesirably high in the charging process, a power reduction can be effected, for example, by the following combination of the switching states: (i) The first switching element 201 is switched to an open state, whereby the electrical bridge is interrupted or the pre-charging resistor is switched into the power line, whereby it contributes to reducing the power of the charging process. (ii) The second switching element 202 is switched to a closed state, whereby the shunt line with the discharge resistor 250 is closed. As a result, the connected discharge resistor contributes to the power reduction of the charging process. (iii) The third switching element 203 is in a closed state, so that the secondary coil is partially bridged. This results in a change in the resonance frequency of the secondary coil, so that the above-mentioned magnetic coupling between the primary coil and the detuned secondary coil is reduced.

3 shows a schematic representation of the vehicle-side loading module 131 , A first part 320 a monitoring line system is through the charging module 131 laid. A second part 321 of the monitoring line system is through a plug connection 310 through which of the secondary coil 122 assigned. A third part 322 of the monitoring line system is through a plug connection 311 through which the energy storage 140 assigned. The second and third part of the monitoring line system is electrically connectable to the first part when the respective plug connections 310 . 311 are plugged in. One at the entrance 340 the monitoring line system fed current can at an output 350 be detected when both plug connections 310 . 311 are plugged in.

LIST OF REFERENCE NUMBERS

100

Inductive charging device

110

Primary rectifier module

120

Inductive energy transfer device

121

primary coil

122

secondary coil

130

Vehicle-side module

131

Vehicle-side charging module

140

energy storage

150

Head of a 3-phase voltage

151

Pulse width modulated high frequency voltage

152

Pulse width modulated high frequency voltage

153

direct current

201

First switching element

202

Second switching element

203

Third switching element

204

Fourth switching element

205

rectifier

206

power line

210

capacitor

220

measuring resistor

230

evaluation

240

precharging

250

discharge

260

voltage divider

270

Tap for voltage measurement

280

Tap for current measurement

290

communication module

310

Secondary coil side plug connection

311

Energy storage side connector

320

First part of the monitoring system

321

Second part of the monitoring system

322

Third part of the monitoring system

340

Entrance of the monitoring system

350

Output of the monitoring system

Claims (11)

Vehicle-side charging module for inductive charging of an energy storage device ( 140 ) of an electromobile motor vehicle using an inductive energy transfer device ( 120 ), the on-board charging module ( 131 ) having a power line ( 206 ) located between an input and an output of the charging module ( 131 ), an electrical measuring device, which the power line ( 206 ) and which are used to measure an electrical quantity of a charging process of the energy store ( 140 ) is set up, an evaluation unit ( 230 ) which is coupled to the electrical measuring device and which is arranged to (i) compare the measured electrical quantity with a predetermined limit value and (ii) if the measured electrical quantity exceeds the predetermined limit value, generate a triggering signal, and a safety device, which with the evaluation unit ( 230 (i) receiving the generated triggering signal; and (ii) in response to receiving the triggering signal, reducing the charging by means of detuning a resonant circuit having a secondary coil ( 122 ) of the energy transmission device ( 120 ) and a compensation capacitor ( 210 ), the safety device being based on a switching element ( 203 ) is configured to partially bridge the secondary coil. Vehicle-side charging module according to the preceding claim, wherein the measuring device has a current sensor and the electrical variable has a current intensity of a charging current for the energy store ( 140 ) through the power line ( 206 ). Vehicle-side charging module according to one of the preceding claims, wherein the measuring device has a voltage sensor and the electrical variable is a voltage level of a charging voltage for the energy store ( 140 ), which on the power line ( 206 ) is present. Vehicle-side charging module according to one of the preceding claims, wherein the safety device (i) has one in the power line ( 206 ) precharging resistance ( 240 ) and (ii) a precharge resistance ( 240 ) bridging electrical bridge with a first switching element ( 201 ), wherein in a first switching state of the first switching element of the pre-charging resistor ( 240 ) is bridged by means of the electrical bridge and wherein the first switching element is arranged to interrupt the bridge in response to a first partial signal of the trigger signal. Vehicle-side charging module according to one of the preceding claims, wherein the safety device has a bypass line with (i) a discharge resistor ( 250 ) and (ii) a second switching element ( 202 ), wherein in a first switching state of the second switching element ( 202 ) the shunt line is interrupted and wherein the second switching element ( 202 ) is arranged to close the shunt line in response to a second sub-signal of the trigger signal. Vehicle-side charging module according to one of the preceding claims, wherein the safety device has a tapping line with a third switching element ( 203 ), wherein an input-side end of the tap line with a tapping point of a secondary coil ( 122 ) or a compensation capacitor ( 210 ) of the inductive energy transmission device ( 120 ) is electrically connectable and wherein in response to a third partial signal of the triggering signal of the electrical resonance circuit, which the secondary coil ( 122 ) and the compensation capacitor ( 210 ) is detunable. Vehicle-side charging module according to one of the preceding claims, further comprising a part of a monitoring line system ( 320 ), which by means of plug connections ( 310 . 311 ) with another part of the monitoring system ( 321 . 322 ) is electrically conductively connectable, wherein a first plug connection ( 310 ) of the plug connections ( 310 . 311 ) is associated with the inductive energy transmission device and wherein a second plug connection ( 311 ) of the plug connections ( 310 . 311 ) the energy storage ( 140 ) assigned. Vehicle-side charging module according to one of the preceding claims, wherein the evaluation unit ( 230 ) is arranged to receive a reading from a magnetic field sensor and to effect the power reduction of the charging in response to receiving the reading. Vehicle-side charging module according to one of the preceding claims, further comprising a rectifier ( 205 ) for rectifying one of the inductive energy transfer device ( 120 ) provided AC power signal. Vehicle-side charging module according to one of the preceding claims, wherein the evaluation unit ( 230 ) is arranged to transmit the triggering signal to one of the inductive energy transfer devices ( 120 ) upstream power supply system to effect a power reduction of the charging process. Method for inductively charging an energy store ( 140 ) of an electromobile motor vehicle using an inductive energy transfer device ( 120 ), the method comprising measuring, by means of a measuring device, an electrical quantity of a charging process of the energy store ( 140 ) in a power line ( 206 ), which the inductive energy transfer device ( 120 ) with the energy store ( 140 ), comparing the measured electrical quantity of the charging process with a predetermined limit value by means of an evaluation unit coupled to the electrical measuring device ( 230 ), Generating a trigger signal if the measured electrical quantity exceeds the predetermined limit, receiving the generated trigger signal from a safety device, and reducing a power of the charging by means of the safety device in response to receiving the trigger signal, the power by detuning a resonant circuit ( 122 ), which is a secondary coil ( 122 ) of the energy transmission device ( 120 ) is reduced, and the detuning is carried out by partially bridging the secondary coil ( 122 ).

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