DE102021003579A1 - Device and system for non-contact energy transfer - Google Patents

Abstract

The invention relates to a device (20) for contactless energy transfer to a mobile consumer, comprising an energy source (40) which generates a primary current (I1) and a primary conductor (11) which is laid in the form of a primary loop (21) and a first inductance (L1), wherein the primary conductor (11) is connected to the energy source (40) and the primary current (I1) flows through it. The device (20) comprises a secondary conductor (12) which is laid in the form of a secondary loop (22) and has a second inductance (L2) and a capacitance (C2), the secondary conductor (12) having the capacitance (C2) is connected in such a way that the second inductance (L2) and the capacitance (C2) form an oscillating circuit, and the primary loop (21) and the secondary loop (22) are laid in such a way that the primary conductor (11) and the secondary conductor (12) run parallel over a coupling area with a coupling length (D), and that the primary conductor (11) and the secondary conductor (12) are inductively coupled in the coupling area in such a way that a secondary current (I2) flows through the secondary conductor (12). The invention also relates to a system for contactless energy transmission, comprising a device (20) according to the invention and a mobile consumer which has a pick-up (50) for receiving energy, the pick-up (50) including a tertiary winding (31) and being arranged in this way that the tertiary winding (31) is inductively coupled to the primary conductor (11).

Description

The invention relates to a device for contactless energy transmission to a mobile consumer, comprising an energy source which generates a primary current and a primary conductor which is laid in the form of a primary loop and has a first inductance, the primary conductor being connected to the energy source and from which Primary current is traversed. The invention also relates to a system for contactless energy transmission, comprising a device according to the invention and a mobile consumer, which has a transmitter head for receiving energy.

From the DE 100 53 373 B4 a system for contactless energy transfer is known. The system includes a feed that injects a medium frequency alternating current into an elongated primary conductor. Mobile loads can be moved along the primary conductor and each have a coil that is inductively coupled to the primary conductor. This inductive coupling means that energy can be transmitted from the primary conductor to the consumer.

Also from the DE 10 2006 013 004 A1 a system for contactless energy transmission is known which comprises a feeder which feeds a medium-frequency alternating current into an elongate primary conductor.

From the DE 10 2004 055 1543 B4 a system for contactless energy transfer is known. The system includes a power source connected to an elongate primary conductor. A mobile consumer, which can be moved along the primary conductor, has a pick-up. The pick-up has a winding which is inductively coupled to the primary conductor. This inductive coupling means that energy can be transmitted from the primary conductor to the consumer's pick-up.

From the DE 10 2007 024 293 A1 a system is known which comprises a primary conductor system and at least one device arranged to be movable along it.

From the U.S. 2012/0001497 A1 a system for the wireless transmission of power is known. Said system comprises a power transmitting section and a power receiving section.

From the US 2018/0278095 A1 a system for electromagnetic energy transmission is known which has a primary coil and a secondary coil.

From the EP 2 700 140 B1 a system for inductive energy transfer to a consumer is known. The system includes a primary conductor system to which a secondary winding of the load is inductively coupled.

From the DE 692 27 242 T2 an inductive power distribution system is known. The power distribution system includes a power source, a primary conductive path, and multiple electrical devices.

The invention is based on the object of further developing a device and a system for contactless energy transmission.

The object is achieved according to the invention by a device for contactless energy transmission with the features specified in claim 1. Advantageous refinements and developments are the subject of the dependent claims. The object is also achieved by a system for contactless energy transmission with the features specified in claim 13. Advantageous refinements and developments are the subject of the dependent claims.

A device according to the invention for contactless energy transmission to a mobile consumer comprises an energy source, which generates a primary current, and a primary conductor, which is laid in the form of a primary loop and has a first inductance, the primary conductor being connected to the energy source and having the primary current flow through it . The device comprises a secondary conductor, which is laid in the form of a secondary loop and has a second inductance, and a capacitance, the secondary conductor being connected to the capacitance in such a way that the second inductance and the capacitance form an oscillating circuit, and the primary loop and the Secondary loop are placed such that the primary conductor and the secondary conductor over a coupling area with a coupling length run parallel, and that the primary conductor and the secondary conductor are inductively coupled such that the secondary conductor is traversed by a secondary current.

The primary current in the primary conductor, which preferably has a constant fundamental frequency and a constant current intensity, generates a first magnetic field. The secondary current in the secondary conductor, which has the same fundamental frequency and whose current strength depends on the primary current and on the dimensioning of the oscillating circuit, generates a second magnetic field. The first magnetic field and the second magnetic field are superimposed to form an overall magnetic field. Energy is transferred from the device to the consumer inductively via the overall magnetic field. The power that can be transmitted to the consumer depends in particular on a field strength of the overall magnetic field. The intensity of the secondary current can be adjusted by means of the secondary conductor, in particular by suitable dimensioning of the oscillating circuit. The field strength of the overall magnetic field can thus be adjusted. The power that can be transmitted to the consumer can thus be adjusted. The device according to the invention thus allows the power that can be transmitted to the consumer to be set while the current strength of the primary current remains the same.

According to an advantageous embodiment of the invention, the secondary loop is arranged inside the primary loop. This results in an effective inductive coupling between the primary conductor and the secondary conductor with a small space requirement.

According to a preferred embodiment of the invention, the primary loop has exactly one turn. Said design of the primary loop with exactly one turn requires a short length of the primary conductor and thus a small material requirement.

According to an advantageous embodiment of the invention, the secondary loop has exactly one turn. Said design of the secondary loop with exactly one turn requires a small length of the secondary conductor and thus a small material requirement.

According to another advantageous embodiment of the invention, the secondary loop has a plurality of turns. Said configuration of the secondary loop with a plurality of windings allows adjustment of the second inductance and thus dimensioning of the oscillating circuit. Furthermore, with a plurality of turns, a mutual inductance, which describes the inductive coupling between the primary conductor and the secondary conductor, is increased.

According to an advantageous embodiment of the invention, the resonant circuit is designed in such a way that the primary current and the secondary current flow in phase in the coupling region. The first magnetic field generated by the primary current and the second magnetic field generated by the secondary current are then also in phase. The overall magnetic field generated thus has a field strength that is greater than the field strength of the first magnetic field. In the coupling area, therefore, greater power can be transmitted from the device to the consumer than in an area in which only the primary conductor is located.

According to another advantageous embodiment of the invention, the resonant circuit is designed in such a way that the primary current and the secondary current flow in phase opposition in the coupling region. The first magnetic field generated by the primary current and the second magnetic field generated by the secondary current are then also in antiphase. Assuming that the magnitude of the secondary current is smaller than the primary current, the overall magnetic field generated thus has a field strength that is smaller than the field strength of the first magnetic field. A lower power can therefore be transmitted by the device in the coupling area than in an area in which only the primary conductor is located.

According to an advantageous embodiment of the invention, the intensity of the secondary current is at least approximately the same as the intensity of the primary current. If the primary current and the secondary current flow in phase opposition in the coupling region, the first magnetic field generated by the primary current and the second magnetic field generated by the secondary current cancel each other out and the overall magnetic field is equal to zero. A coupling area designed in this way can be used particularly advantageously in places where there are sources of interference that draw undesired energy from the device. Such sources of interference are, for example, steel reinforcements in a concrete floor, in which the primary conductor and the secondary conductor are laid. In a coupling area designed in this way, energy transfer to the consumer is not possible.

According to another advantageous embodiment of the invention, the current intensity of the secondary current is at least approximately half the current intensity of the primary current. If the primary current and the secondary current flow in phase in the coupling region, the first magnetic field generated by the primary current and the second magnetic field generated by the secondary current increase to form a total magnetic field with a field strength of 150% of the field strength of the first magnetic field. The power that can be transmitted in the coupling area from the device to the consumer thus corresponds to 150% of the power that can be transmitted in an area in which only the primary conductor is located.

According to an advantageous embodiment of the invention, the primary loop has a loop width that is greater than the coupling length. The coupling length and the space requirement of the coupling area are therefore relatively small. Such a coupling area can advantageously be used in places where sources of interference are present, which draw undesired energy from the device when the first magnetic field and the second magnetic field cancel each other out in the coupling area.

According to another advantageous embodiment of the invention, the primary loop has a loop width that is smaller than the coupling length. The coupling length of the coupling area is therefore relatively large. As a result, energy can be transmitted to the consumer over a large coupling area.

Preferably, the primary loop and the secondary loop have approximately the same loop width. As a result, a mutual inductance, which describes the inductive coupling between the primary conductor and the secondary conductor, is increased.

A system according to the invention for contactless energy transmission comprises a device according to the invention for contactless energy transmission and a mobile consumer, which has a pick-up for receiving energy, the pick-up including a tertiary winding and being arranged such that the tertiary winding is inductively coupled to the primary conductor.

Contactless energy transmission from the device to the consumer is thus possible in the system according to the invention. The energy is transmitted inductively via the tertiary winding of the pick-up to the mobile consumer.

According to an advantageous embodiment of the invention, the pick-up is arranged, at least temporarily, in such a way that the tertiary winding is inductively coupled to the primary conductor and to the secondary conductor in the coupling region. Energy is transmitted from the device to the consumer inductively via the overall magnetic field, the field strength of which can be adjusted. The power that can be transmitted to the consumer can thus be adjusted.

According to a preferred embodiment of the invention, the pick-up can be moved along the primary conductor. The consumer is thus able to inductively absorb energy from the device while traveling along the primary conductor.

The invention is not limited to the combination of features of the claims. For the person skilled in the art, there are further meaningful combinations of claims and/or individual claim features and/or features of the description and/or the figures, in particular from the task and/or the task arising from comparison with the prior art.

• 1: eine schematische Darstellung eines Systems zur berührungslosen Energieübertragung,
• 2: ein vereinfachtes elektrisches Ersatzschaltbild einer Vorrichtung zur berührungslosen Energieübertragung und
• 3: qualitativ eine Abhängigkeit eines Sekundärstroms von einer Kapazität eines Kondensators.

The invention will now be explained in more detail with reference to figures. The invention is not limited to the exemplary embodiments shown in the figures. The figures represent the subject matter of the invention only schematically. It shows:

• 1 : a schematic representation of a system for contactless energy transmission,
• 2 : a simplified electrical equivalent circuit diagram of a device for contactless energy transmission and
• 3 : qualitatively a dependency of a secondary current on a capacitance of a capacitor.

1 shows a schematic representation of a system for contactless energy transmission. The system includes a device 20 for contactless energy transmission and a mobile consumer. The mobile consumer is, for example, an autonomously driving vehicle. The mobile consumer has a pick-up 50 for receiving energy. The pick-up 50 includes a tertiary winding 31.

The device 20 is used for contactless energy transmission to the mobile consumer. The device 20 comprises an energy source 40, which generates a primary current I1, and a primary conductor 11. The primary conductor 11 is laid in the form of a primary loop 21 and has a first inductance L1. The primary conductor 11 is electrically connected to the energy source 40 and has the primary current I1 flowing through it. In the present case, the primary loop 21 has exactly one turn.

The energy source 40 has a current source 42 which supplies the primary current I1. The primary current I1 is a medium-frequency alternating current and has a fundamental frequency F0 of 25 kHz or 50 kHz, for example. A current intensity of the primary current I1 is 60 A or 90 A, for example.

The primary conductor 11 is laid, for example, in a floor on which the mobile consumer moves. The primary conductor 11 is laid close to the surface of the floor. The pick-up 50 of the mobile consumer is located in the immediate vicinity of the ground above the primary conductor 11. In particular, the pick-up 50 is arranged in such a way that the tertiary winding 31 is inductively coupled to the primary conductor 11. Energy can thus be transmitted from the energy source 40 via the primary conductor 11 to the tertiary winding 31 and thus to the consumer.

The mobile consumer drives on the floor, for example in a technical installation such as a production plant. In this case, the pick-up 50 can be moved in particular along the primary conductor 11 . Thus, while the mobile consumer is driving, energy can be transmitted from the device 20 to the consumer.

The device 20 for contactless energy transmission also includes a secondary conductor 12. The secondary conductor 12 is laid in the form of a secondary loop 22 and has a second inductance L2. The device 20 for contactless energy transmission also includes a capacitance C2. The secondary conductor 12 is electrically connected to the capacitance C2 in such a way that the second inductance L2 and the capacitance C2 form an oscillating circuit. The secondary conductor 12 is also laid, for example, in the floor on which the mobile consumer is moving. The secondary conductor 12 is laid close to the surface of the floor.

The primary loop 21 and the secondary loop 22 are laid in such a way that the primary conductor 11 and the secondary conductor 12 run parallel over a coupling region with a coupling length D. The primary conductor 11 and the secondary conductor 12 are inductively coupled in the coupling region in such a way that a secondary current I2 flows through the secondary conductor 12 . The primary current I1 in the primary conductor 11 induces the secondary current I2 in the secondary conductor 12 via said inductive coupling.

In the representation shown here, the pick-up 50 of the mobile consumer is in the coupling area and in the immediate vicinity of the ground above the secondary conductor 12. In particular, the pick-up 50 is arranged in such a way that the tertiary winding 31 is also inductively coupled to the secondary conductor 12. The pickup 50 is thus arranged in the coupling region in such a way that the tertiary winding 31 is inductively coupled to the primary conductor 11 and to the secondary conductor 12 .

In the present case, the secondary loop 22 is arranged inside the primary loop 21 . In this case, the primary conductor 11 and the secondary conductor 12 are laid directly next to one another in the coupling region. The primary loop 21 and the secondary loop 22 thus have an approximately equal loop width B. The loop width B is an extension of the primary loop 21 and the secondary loop 22 perpendicular to the coupling length D. In the present case, the loop width B is smaller than the coupling length D. It is also conceivable that the loop width B is greater than the coupling length D.

In the coupling area, the primary conductor 11 and the secondary conductor 12 are laid approximately in a plane which extends parallel to the surface of the floor. In the present case, the secondary loop 22 has exactly one turn. It is also conceivable that the secondary loop 22 has a plurality of turns.

The primary current I1 in the primary conductor 11 generates a first magnetic field. The secondary current I2 in the secondary conductor 12 creates a second magnetic field. The first magnetic field and the second magnetic field are superimposed to form an overall magnetic field. In an energy transfer from the device 20 to the Consumer penetrates the total magnetic field, the tertiary winding 31 of the pick-up 50. The power that can be transmitted to the consumer depends in particular on a field strength of the total magnetic field.

2 shows a simplified electrical equivalent circuit diagram of in 1 device 20 shown for contactless energy transmission. As already mentioned, the device 20 comprises the energy source 40 which has a current source 42 . The current source 42 supplies the primary current I1 with the fundamental frequency F0. The primary current I1 flows through the primary conductor 11 with the first inductance L1. In this case, a first voltage U1 drops across the energy source 40 .

The secondary current I2 flows through the secondary conductor 12 with the second inductance L2 and through the capacitance C2. A second voltage U2 drops across the capacitance C2. As already mentioned, the second inductor L2 and the capacitor C2 form an oscillating circuit. The inductive coupling between the primary conductor 11 and the secondary conductor 12 is represented by a mutual inductance M.

In the primary loop 21, the following applies approximately, with the angular frequency ω=2π F0: $$\text{u}1=\text{l}1*\text{L}1*\mathrm{\omega }+\text{l}2*\text{M}*\mathrm{\omega }$$

In the secondary loop 22, with the angular frequency ω = 2 π F0, the following applies approximately: $$\text{u}2=\text{l}1*\text{M}*\mathrm{\omega }+\text{l}2*\text{L}2*\mathrm{\omega }\mathrm{=}\text{l}2\text{/}\left(\text{C}2*\mathrm{\omega }\right)$$

From [Eq. 2] follows: $$\begin{array}{c}\text{l}1*\text{M}*\mathrm{\omega }=\text{l}2\text{/}\left(\text{C}2*\mathrm{\omega }\right)-\text{l}2*\text{L}2*\mathrm{\omega }\\ \left(\text{l}1\text{/l}2\right)*\text{M}=1\text{/}\left(\text{C}2*\mathrm{\omega }2\right)-\text{L}2\end{array}$$

The second inductance L2 and the mutual inductance M are largely determined by the configuration of the primary conductor 11 and the secondary conductor 12 and the geometric arrangement of the primary loop 21 and the secondary loop 22. The capacitance C2 can be selected depending on the desired application.

From [Eq. 3] follows: When L2 < 1 / (C2 * ω2) then I1 / I2 > 0 C2 < 1 / (L2 * ω2) then I1 / I2 > 0

If I1/I2 > 0 then the primary current I1 and the secondary current I2 flow in phase. The first magnetic field generated by the primary current I1 and the second magnetic field generated by the secondary current I2 are then also in phase. The overall magnetic field generated thus has a field strength that is greater than the field strength of the first magnetic field. A greater power can thus be transmitted to the consumer in the coupling area than in an area in which only the primary conductor 11 is located.

From [Eq. 3] also follows: When L2 > 1 / (C2 * ω2) then I1 / I2 < 0 C2 > 1 / (L2 * ω2) then I1 / I2 < 0

If I1 / I2 < 0, the primary current I1 and the secondary current I2 flow in phase opposition. The first magnetic field generated by the primary current I1 and the second magnetic field generated by the secondary current I2 are then also in antiphase. Assuming that the magnitude of the secondary current I2 is smaller than that of the primary current I1, the total magnetic field generated thus has a field strength that is smaller than the field strength of the first magnetic field. In the coupling area, therefore, less power can be transmitted to the consumer than in an area in which only the primary conductor 11 is located.

From [Eq. 3] follows further: When L2 = 1 / (C2 * ω2) then I1 / I2 = 0 C2 = 1 / (L2 * ω2) then I1 / I2 = 0

If I1 / I2 = 0 then ω2 = 1 / (C2 * L2). In this case, the oscillating circuit therefore has a resonant frequency FR which corresponds to the fundamental frequency F0. $$\text{FR}=1\text{/}\left(2\mathrm{\pi }\left(\text{square}(\text{L}2*\text{C}2\right)\right)=\text{<figure-callout id="0" label="f" filenames="DE102021003579A1\_0007.png" state="{{state}}">f</figure-callout>}0$$

If the resonant frequency FR of the oscillating circuit corresponds to the fundamental frequency F0, a relatively large secondary current I2 flows, which may cause the device 20 to be destroyed.

3 12 qualitatively shows a dependency of the secondary current I2 on the capacitance C2 of the capacitor. The capacitance C2 of the capacitor is plotted on the abscissa, and the secondary current I2 is plotted on the ordinate. The second inductance L2 and the mutual inductance M are assumed to be constant. The capacitance C2 of the capacitor is variable.

If C2 < 1/(L2 * ω2) then the primary current I1 and the secondary current I2 flow in phase. At the correspondingly marked point, the amperage of the secondary current I2 is half the amperage of the primary current I1. In this case, the power that can be transmitted to the load in the coupling region corresponds to 150% of the power that can be transmitted in a region in which only the primary conductor 11 is located.

If C2 = 1 / (L2 * ω2) then the secondary current I2 becomes infinitely large. In this case, the resonant frequency FR of the resonant circuit corresponds to the fundamental frequency F0.

If C2 > 1/(L2 * ω2) then the primary current I1 and the secondary current I2 flow in opposite phase. At the correspondingly marked point, the intensity of the secondary current I2 is the same as the intensity of the primary current I1. In the coupling region, the first magnetic field generated by the primary current and the second magnetic field generated by the secondary current cancel each other out and the total magnetic field is equal to zero.

Reference List

11

primary conductor

12

secondary conductor

20

Device for contactless energy transfer

21

primary loop

22

secondary loop

31

tertiary winding

40

energy source

42

power source

50

pick-up

D

coupling length

B

loop width

F0

fundamental frequency

ω

angular frequency

FR

resonant frequency

C2

capacity

I1

primary current

I2

secondary current

L1

first inductance

L2

second inductance

M

mutual inductance

U1

first tension

U2

second tension

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was 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.

Patent Literature Cited

• DE 10053373 B4 [0002]
• DE 102006013004 A1 [0003]
• DE 1020040551543 B4 [0004]
• DE 102007024293 A1 [0005]
• US 2012/0001497 A1 [0006]
• US 2018/0278095 A1 [0007]
• EP 2700140 B1 [0008]
• DE 69227242 T2 [0009]

Claims (15)

Device (20) for contactless energy transmission to a mobile consumer, comprising an energy source (40) which generates a primary current (I1) and a primary conductor (11) which is laid in the form of a primary loop (21) and a first inductance (L1 ), wherein the primary conductor (11) is connected to the energy source (40) and the primary current (I1) flows through it, characterized in that the device (20) has a secondary conductor (12) which in the form of a secondary loop (22) is laid and has a second inductance (L2), and a capacitance (C2), wherein the secondary conductor (12) is connected to the capacitance (C2) in such a way that the second inductance (L2) and the capacitance (C2) form an oscillating circuit form, and wherein the primary loop (21) and the secondary loop (22) are laid such that the primary conductor (11) and the secondary conductor (12) run parallel over a coupling region with a coupling length (D), and that the The primary conductor (11) and the secondary conductor (12) are inductively coupled in the coupling region in such a way that a secondary current (I2) flows through the secondary conductor (12). Device (20) after claim 1 , characterized in that the secondary loop (22) is arranged inside the primary loop (21). Device (20) according to at least one of the preceding claims, characterized in that the primary loop (21) has exactly one turn. Device (20) according to at least one of the preceding claims, characterized in that the secondary loop (22) has exactly one turn. Device (20) according to at least one of Claims 1 until 3 , characterized in that the secondary loop (22) has a plurality of turns. Device (20) according to at least one of the preceding claims, characterized in that the resonant circuit is designed in such a way that the primary current (I1) and the secondary current (I2) flow in phase in the coupling region. Device (20) according to at least one of Claims 1 until 5 , characterized in that the resonant circuit is designed in such a way that the primary current (I1) and the secondary current (I2) flow in phase opposition in the coupling region. Device (20) according to at least one of the preceding claims, characterized in that the intensity of the secondary current (I2) is at least approximately the same as the intensity of the primary current (I1). Device (20) according to at least one of Claims 1 until 7 , characterized in that a current of the secondary current (I2) is at least approximately half as large as a current of the primary current (I1). Device (20) according to at least one of the preceding claims, characterized in that the primary loop (21) has a loop width (B) which is greater than the coupling length (D). Device (20) according to at least one of the preceding claims, characterized in that the primary loop (21) has a loop width (B) which is smaller than the coupling length (D). Device (20) according to at least one of the preceding claims, characterized in that the primary loop (21) and the secondary loop (22) have approximately the same loop width (B). System for non-contact energy transmission, comprising a device (20) according to at least one of the preceding claims, and a mobile consumer, which has a transmitter head (50) for receiving energy, wherein the pick-up (50) comprises a tertiary winding (31) and is arranged such that the tertiary winding (31) is inductively coupled to the primary conductor (11). system after Claim 13 , characterized in that the pick-up (50) is arranged such that the tertiary winding (31) is inductively coupled to the primary conductor (11) and to the secondary conductor (12) in the coupling region. system according to one of the Claims 13 until 14 , characterized in that the pick-up (50) is movable along the primary conductor (11).

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