CN103390937A

CN103390937A - Wireless energy transfer

Info

Publication number: CN103390937A
Application number: CN201310162809XA
Authority: CN
Inventors: J·马克
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2012-05-08
Filing date: 2013-05-06
Publication date: 2013-11-13
Anticipated expiration: 2033-05-06
Also published as: CN103390937B; FR2990575A1; DE102012207585A1

Abstract

A transmitter for a wireless energy transfer includes a resonant circuit, which in turn comprises a transmitter coil for providing an alternating electromagnetic field and a drive for providing an oscillating current through the transmitter coil, and control means for controlling an amplitude of the oscillating current as a function of a change in the inductance of the coil.

Description

Wireless energy transfer

Technical field

The present invention relates to a kind of wireless energy transfer.The invention particularly relates to a kind of wireless energy transfer between transmitter and receiver, to the receiver electric energy of feeding.

Background technology

For example for charging, do not use by the battery of giving small electrical equipment the wireline interface that leads to charging device for this reason, known inductively intercoupling as the charging device of transmitter with as the small electrical equipment of receiver, thus can the electromagnetic ground electric energy transmitting.At this, transmitter comprises the transmission coil for generation of the electromagnetism alternating field, and receiver comprises for the electromagnetism alternating field being converted to the receiving coil of electric current.

Whether the transmitter None-identified receiver commonly used that is used for the electric flux transmission is positioned at the electromagnetic effect scope.Transmitter is not taken described situation ground into account and is produced alternating field, may produce thus unnecessary energy consumption.Can be in the situation that there be receiver in object that can conduct electricity or magnetizable or do not exist receiver to be arranged in the electromagnetic effect scope of transmitter, and described object can heat and therefore endanger security of operation by alternating field.Advise, by transmitter by exchanging messages to realize the identification of receiver, yet the expense of this solution is considerable.

US4,942,352 illustrate a kind of wireless energy transfer system, wherein are provided with magnetic switch, and the state of described magnetic switch notifies the existence of receiver to transmitter, thus transmitter is only in the situation that exist receiver that the electromagnetism alternating field is provided.

US5,536, but 979 illustrate a kind of charging device of the equipment of the small electrical for recharge, wherein the receiving coil of the transmission coil of charging device and mini-plant is by means of the armature magnetic coupling, the part of wherein said armature is retained in mini-plant, thereby it can be with mini-plant together away from charging device.If mini-plant is not arranged in the electromagnetic effect scope that sends coil, by away from the alternating field that is provided by charging device can be provided.

Summary of the invention

The present invention is based on following task: propose to be used for transmitter and the system of wireless energy transfer, described transmitter and described system allow to reduce simply when not having receiver to be arranged in the electromagnetic effect scope of transmitter the electromagnetism alternating field that is provided by transmitter.Another task of the present invention is to propose to be used for for control the correlation method of the transmitter of wireless energy transfer.

The present invention solves these tasks by means of transmitter, the system and method for the feature with independent claims.Dependent claims provides again preferred implementation.

Transmitter for wireless energy transfer according to the present invention comprises resonant tank, and described resonant tank comprises be used to the transmission coil that the electromagnetism alternating field is provided and is used for providing the trigger equipment that flows through the oscillating current that sends coil and the control appliance that is used for controlling according to the change of the inductance that sends coil the amplitude of described oscillating current.

Can easily and with larger reliability determine to send the inductance of coil or the change of described inductance on circuit engineering.Do not need to realize the active system that exchanges messages between transmitter and receiver.Thus for example can be by transmitter to following receiver feed: described receiver comprises battery, and described battery discharges so deeply, makes and can't realize and the communicating by letter of transmitter.

Can infer in the coverage that sends coil and have receiver by determined inductance or its change, thus can be in the situation that do not exist receiver to reduce to be converted to by sending coil the electrical power of electromagnetism alternating field.Advantageously, can transmitter and the commercial receiver that is used for wireless energy transfer commonly used is combined, and need not the change of receiver aspect.Neither need to, for detection of the mechanical organ of the existence of transmitter, not need the equipment for the message between transmitter and receiver yet.Can be in the situation that do not exist receiver to reduce the energy consumption of transmitter, and can reduce by in the situation that exist or danger that the heating that do not exist receiver to be arranged in the magnetizable object that maybe can conduct electricity of the electromagnetic effect scope that sends coil causes.In addition, describedly determine to be sane and to be jamproof for the electromagnetic interference in another source.

Preferably, resonant tank also comprises that resonant capacitance and control appliance comprise the equipment for the cross-over connection resonant capacitance, in order to reduce the amplitude of oscillating current.Sort circuit can be reduced to the amplitude that flows through the oscillating current that sends coil simply and approach zero value.Thus, can be in the situation that do not exist receiver to make during transmitter is transitioned into energy saver mode, described receiver can easily be transitioned into again normally in service by opening jumper device from described energy saver mode.

In a kind of particularly preferred execution mode, control appliance is provided for: if determined inductance or determined inductance change, indicate the receiver that does not exist for wireless energy transfer, cross-over connection resonant capacitance in the electromagnetic effect scope that sends coil.

In one embodiment, control appliance is provided for determining to send based on the change of the frequency of oscillating current the change of the inductance of coil.For this reason, can determine frequency and itself and predetermined threshold value are compared.

In another embodiment, control appliance is provided for determining based on the change of the damping that sends coil the change of the inductance of transmission coil.Can determine damping and determined value and a threshold value are compared according to electrical quantity.In other embodiments, also can determine to send other electrical quantitys at coil place and it is compared with a threshold value individually or after association, in order to determine how to control the amplitude of oscillating current.At this, preferably make every effort to the decision of binary, thus control appliance or do not limit oscillating current or oscillating current is restricted to minimum value.

In another embodiment, transmitter comprises the separation equipment that resonant tank is separated with the external circuit electricity for during the resonant capacitor cross-over connection.Thus, resonant tank can be during jump time electric loading less, thereby its vibration ability unimpaired or in the situation that further the reducing of the oscillating current that does not exist receiver also can realize flowing through to send coil.

Separation equipment can comprise gate-controlled switch, and described gate-controlled switch preferably can be with above-described jumper device by co-operate.Alternatively, separation equipment can comprise diode, and described diode is guided resonant tank into from external circuit on conducting direction, thus described separation equipment blocking-up when the voltage on the voltage ratio resonant tank on external circuit is enough low.Can realize thus simple and self-activating separation equipment.

System for wireless energy transfer according to the present invention comprises described transmitter and for the electromagnetism alternating field being converted to the receiver of electric energy, wherein said system is provided for when receiver is arranged in the electromagnetic effect scope of described transmitter, energy being transferred on receiver from transmitter.

Comprise the change of inductance of transmission coil of the resonant tank that detects transmitter and the step of controlling the amplitude of the oscillating current that flows through the transmission coil according to described change according to the method for the transmitter for control being used for wireless energy transfer according to the present invention.

Described method can be easily in the situation that realize by means of electronic technology structural detail commonly used.In a kind of flexible program, described method also can be passed through the equipment of control appliance, especially programmable little processing controls and realize.

Description of drawings

Describe in more detail the present invention referring now to accompanying drawing, accompanying drawing illustrates:

Fig. 1: the system that is used for wireless energy transfer;

Fig. 2: in the situation that the equivalent circuit diagram of the transmitter in resonant capacitor cross-over connection Fig. 1;

Fig. 3: the flow chart of method that is used for the transmitter of control chart 1 and Fig. 2.

Embodiment

Fig. 1 illustrates the system 100 for wireless energy transfer.System 100 comprises transmitter 105 and receiver 110, and described transmitter and described receiver can inductively intercouple.Transmitter 105 comprises resonant tank 115, and described resonant tank forms by sending coil 120 and trigger equipment 125.In the example shown execution mode, trigger equipment 125 comprises two gate-controlled switches 135 and 140, for example transistor, consists of, and described two gate-controlled switches dispose two

diodes

145 and 150 in couples.Each switch 135,140 with a diode 145,150 in parallel.In addition, trigger equipment 125 comprises control device 155, so that Closing Switch 135 and 140 alternately.

Resonant tank 115 preferably also comprises resonant capacitor 160.Control appliance 165 is provided for controlling the electric current that flows through transmission coil 120.Shown in preferred implementation, control appliance 165 is connected with gate-controlled switch 170, described gate-controlled switch and resonant capacitor 160 are connected in parallel.

Resonant tank 115 is by the voltage feed that applies on optional intermediate circuit capacitor 175.By switch 180 or alternatively also by diode 185, intermediate circuit capacitor 175 or resonant tank 115 can be connected or with it, separate with the (not shown) circuit of outside.At this, when switch 170 was closed, switch 180 was preferably opened.Switch 170,180 for example can consist of transistor.

Receiver 110 comprises receiving coil 190 and electrical appliance 195, and described electrical appliance exemplarily comprises chargeable storage battery and charging regulator in the diagram of Fig. 1.Receiver 110 for example can consist of small electrical equipment, and its storage battery can wirelessly charge at transmitter 105 places, and its mode is, receiving coil 190 is placed in the electromagnetic effect scope of transmission coil 120 of transmitter 105.Transmitter 105 preferably is used for and the feed part of the power supply unit that network is connected of electric energy.

Resonant tank 115 preferably is provided for the natural frequency vibration, and described natural frequency depends primarily on the inductance of transmission coil 120 and the electric capacity of resonant capacitor 160.For excited oscillation, control device 155 is Closing Switch 135 or 140 alternately.For this reason, control device 155 can be sampled and itself and one or two threshold value is compared the voltage that applies on transmission coil 120.By being alternately closed switch 135 or 140, with the electric energy that applies on intermediate circuit capacitor 175 to resonant tank 115 feeds.Resonant tank 115 produces and flows through the intimate sine-shaped oscillating current that sends coil 120, and transmission coil 120 provides the electromagnetism alternating field in environment in its vicinity.Near described, environment is here also referred to as the electromagnetic effect scope.

If the receiving coil 190 of receiver 110 is arranged in the electromagnetic effect scope that sends coil 120, induce oscillating current in receiving coil 190, described oscillating current can be consumed by electrical appliance 195.Provide the required energy of described electric current to obtain from the electromagnetism alternating field that sends coil 120.

The inductance that sends coil 120 changes with the distance that sends coil 120 along with receiving coil 190 or by existing receiving coil 190 to change in the electromagnetic effect scope.If inductance changes, the resonance frequency of resonant tank 115 also changes.Control appliance 165 is provided for when receiving coil 190 is not arranged in the electromagnetic effect scope that sends coil 120 changing or in the situation that the frequency shift of the voltage that applies on resonant capacitor 110 reduces to flow through the electric current that sends coil 120 in resonance frequency.For this reason, control appliance Closing Switch 170, thereby resonant capacitor 160 short circuits.This causes following effect on the one hand: large value of the resonance frequency shift of resonant tank 115, and send on the other hand voltage on coil 120 and no longer reach one or more threshold values of control device 155, thereby switch 135 and 140 is forever opened.

Fig. 2 illustrates beyond receiver 110 is arranged in the coverage that sends coil 120 and the equivalent circuit diagram of resonant capacitor 160 transmitter 105 of Fig. 1 during by switch 170 cross-over connection.In this case, switch 180 be also open or diode 185 block, thereby save this two elements and connected parts in diagram.

Direct voltage on intermediate circuit capacitor 175 is by voltage source 205 modelings.Two switches 135 and 140 and control their control device 155 have been saved.Keep the

diode

145 and 150 with parasitic capacitance 210 and 215.Switch 170 and the control appliance 165 of intermediate circuit capacitor 160, cross-over connection intermediate circuit capacitor have been saved equally.Send coil 120 and have parasitic capacitance 220.The inductance that sends coil 120 can be by receiving coil 190 and the distance affects that sends coil 120, and wherein consider: distance is excessive in the illustrated case, in order to the inductance that sends coil is produced the impact of being worth mentioning.

Circuit is corresponding to typical circuit power parts shown in figure 2.Remaining resonant tank 115 tends to vibrate by parasitic capacitance 210,215 and 220.Yet formed vibration is because the little effective capacitance 210 to 220 of comparing of the electric capacity of resonant capacitor 160 with in Fig. 1 has much higher resonance frequency, and the vibration that causes has much smaller amplitude.

The higher-order of oscillation of the resonant tank 115 by having the excitation that reduces, the amplitude that flows through on the one hand the electric current that sends coil 120 reduces, thus on the other hand resonant tank 115 preferably keep resonant tank 115 places in vibration electrical characteristics---the frequency of oscillation or the damping that especially send coil 120 places can be used in determining of inductance 120.Change again by the receiving coil 190 near receiver 110 if send the inductance of coil 120, can open the switch 170 in Fig. 1, in order at normal resonant capacitor 160 with activation in service, rerun transmitter 105.

Fig. 3 illustrates the flow chart for the method 300 of the transmitter 105 of control chart 1 and Fig. 2.Method 300 starts in one of step 305 or 310.The change of the frequency of the resonant tank 115 of definite transmitter 105 in step 305, determine the change of the damping of transmission coil 120 in step 310.Two steps all have the purpose of the change of the inductance of determining transmission coil 120.In the execution mode that substitutes, also can send based on another electrical quantity the determining of inductance of coil 120.

Check in following step 315: change and whether surpass predetermined threshold value.In a kind of alternate embodiments, can also indicate the absolute of parameter of the inductance that sends coil 120 to determine in

step

305 or 310, wherein carry out the comparison of determined value and predetermined threshold value in step 315.

According to comparative result, method 300 or with step 320, continue or with step 325, continue, by switch 170 cross-over connection resonant capacitors 160 and open alternatively switch 180, discharge resonant capacitors 160 and Closing Switch 180 alternatively by switch 170 in step 325 in step 320.

Method 300 turns back to initially subsequently, and can be with the new flow process at the beginning of

step

305 or 310.

Claims

1. transmitter (105) that is used for wireless energy transfer, it comprises:

Resonant tank (115), described resonant tank comprise be used to the transmission coil (120) that the electromagnetism alternating field is provided and be used for providing the trigger equipment (125) of the oscillating current that flows through described transmission coil (120),

It is characterized in that control appliance (165), it is used for controlling according to the change of the inductance of described transmission coil (120) amplitude of described oscillating current.

2. transmitter according to claim 1 (105), wherein, described resonant tank (115) also comprises resonant capacitance (160), and described control appliance (165) comprises for the equipment (170) of the described resonant capacitance of cross-over connection (160) with the amplitude that reduces described oscillating current.

3. transmitter according to claim 2 (105), wherein, described control appliance (165) is provided for: if the change of described inductance prompting does not exist the receiver (110) for wireless energy transfer, the described resonant capacitance of cross-over connection (160) in the electromagnetic effect scope of described transmission coil (120).

4. transmitter described according to any one in the claims (105), wherein, described control appliance (165) is provided for determining based on the change of the frequency of described oscillating current the change of the inductance of described transmission coil (120).

5. transmitter described according to any one in the claims (105), wherein, described control appliance (165) is provided for determining based on the change of the damping of described transmission coil (120) change of the inductance of described transmission coil (120).

6. transmitter described according to any one in the claims (105), wherein, described transmitter also comprises for the separation equipment (180,185) that during described resonant capacitor cross-over connection, described resonant tank (115) is separated with the external circuit electricity.

7. according to claim 6 transmitter (105), wherein, described separation equipment comprises gate-controlled switch (180).

8. transmitter according to claim 6 (105), wherein, described separation equipment comprises diode (185), described diode is guided described resonant tank (115) into from external circuit on conducting direction.

9. system (100) that is used for wireless energy transfer, it comprises according to the described transmitter of any one (105) in aforementioned claim and receiver (110), described receiver is used for the electromagnetism alternating field is converted to electric energy, while with the described receiver of box lunch (110), being arranged in the electromagnetic effect scope of described transmitter (105), energy is transferred to described receiver (110) from described transmitter (105).

10. one kind is used for the method (300) of control for the transmitter (105) of wireless energy transfer, said method comprising the steps of:

The change of the inductance of the transmission coil (120) of the resonant tank (115) of detection (305,310) described transmitter (105);

Control (320,325) according to described change and flow through the amplitude of the oscillating current of described transmission coil (120).