SYSTEM FOR INDUCTIVE TRANSMISSION OF ELECTRICAL POWER TO VEHICLES AND METHOD FOR OPERATING A SYSTEM

Description

[0001] The invention relates to a system for the inductive transmission of electrical power to vehicles and a method for operating a system.

[0002] It is generally known that electrical energy can be transmitted inductively.

[0003] From the EP 0 289 868 A2 The closest state of the art is a system for the inductive transmission of electrical power in which serially arranged charging sections can be switched on or off.

[0004] From the US 5 821 728 A The inductive charging of a road vehicle is known.

[0005] From the GB 2 502 820 A Inductive power supply for rail vehicles is known.

[0006] From the US 7 164 211 B1 A vehicle-assisted power generator is known.

[0007] From the EP 2 873 132 A1 A tuning circuit is known.

[0008] From the GB 2 496 433 A Inductive transfer of electrical energy to a vehicle is known.

[0009] From the FR 2 998 427 A1 is a known inductive charging system for a vehicle battery.

[0010] The invention is therefore based on the objective of further developing a system for contactless energy transmission in an environmentally friendly manner.

[0011] According to the invention, the problem is solved in the system according to the features specified in claim 1 and in the method according to the features specified in claim 6.

[0012] The advantage of this system is that it conserves resources and thus protects the environment by saving energy. If no vehicle is present in one of the charging areas, the switch closes, short-circuiting the primary conductor section in that area and thus de-energizing it. This prevents ohmic losses in the primary conductor section.

[0013] According to the invention Is the respective switch of the respective charging area controllable by a sensor device?

[0014] The sensor device detects the presence of a vehicle in the charging area associated with the sensor device, and in particular, depending on whether a threshold value of inductive coupling between the primary conductor section of the charging area and a secondary winding arranged on the vehicle is exceeded or fallen below, the controllable switch is actuated, in particular opened or closed. It is advantageous that the vehicle is detected when the threshold value is exceeded. However, if the threshold value has not yet been exceeded, the vehicle is either not present or so far away that the inductive coupling is still too weak for the transmission of relevant power.

[0015] A capacitor is also connected in parallel and / or in series to the secondary winding located on the vehicle, so that the associated resonant frequency essentially corresponds to the frequency of the current component impressed into the primary conductor by the AC power source. In this way, the threshold value for determining the coupling strength between the primary conductor section and the secondary winding can be undercut by short-circuiting the secondary winding with a controllable switch on the vehicle. This is also useful, for example, when the vehicle's energy storage system is fully charged and therefore no energy can be absorbed. With the switch open, the vehicle's resonant circuit is active, and therefore inductive coupling is present, provided the vehicle's secondary winding is located close enough to the primary conductor section.

[0016] In an advantageous embodiment, the sensor device is connected to a power supply unit, particularly an electrical device, comprising the AC power source, via a communication channel, in particular a data transmission channel. An advantage of this is that the detection of a vehicle can be forwarded to a centrally located control unit.

[0017] In an advantageous embodiment, the communication channel is implemented using signal lines, wherein data can be transmitted from the power supply unit to the sensor device via the signal lines, in particular wherein the power supply unit and the sensor device are bus participants of a data bus. An advantage of this is that wired and therefore interference-free transmission is possible.

[0018] In an advantageous embodiment, the communication channel comprises signals modulated onto the primary conductor, which are modulated onto the primary conductor by the power supply unit and / or the sensor device, in particular wherein the frequency of the modulated signals is higher than the frequency of the alternating current impressed into the primary conductor by the AC power source, in particular which has a frequency between 10 and 1000 kHz. An advantage of this is that no additional lines are required. The existing cabling necessary for power transmission can therefore be used. This is because the primary conductor and the primary conductor section are suitable for transmitting high current, for example, more than 10 amperes.

[0019] According to the invention The sensor devices are inductively powered from the primary conductor, with each sensor device having a secondary winding inductively coupled to the primary conductor. The advantage of this is that no separate power supply is required, thus reducing wiring effort.

[0020] According to the invention Each sensor device incorporates an energy storage system to buffer interrupted electrical power supplies. The advantage here is that the sensor device's energy consumption during these interruptions is lower than the amount of energy that can be stored in the energy storage system.

[0021] Key features of the procedure for operating a the aforementioned The systems are such that the respective sensor device causes the closing of the switch assigned to the respective sensor device when the vehicle is not detected, particularly in the charging area assigned to the sensor device, or particularly when the vehicle is not present.

[0022] The advantage here is that power losses can be reduced, thus protecting the environment.

[0023] In a preferred embodiment, when a vehicle is detected within the charging area assigned to the sensor device, the switch associated with that charging area is opened. An advantage of this is that the vehicle can be inductively charged with energy.

[0024] In a preferred embodiment, the amount of current impressed into the primary conductor by the AC power source is controlled depending on the number of closed switches in the system. An advantage of this is that the power loss can be reduced even further.

[0025] Further advantages arise from the sub-claims.

[0026] The invention will now be explained in more detail with the help of illustrations: In the Figure 1 A first system according to the invention is schematically sketched. In the Figure 2 Another system according to the invention is schematically sketched.

[0027] As in Figure 1As shown, the system has an AC power source 1 that supplies several stationary charging areas in series, which are intended for the inductive transfer of electrical power to vehicles.

[0028] The alternating current source 1 feeds a medium-frequency current into a primary conductor loop 4, which has a forward conductor and a return conductor that are essentially parallel to each other.

[0029] Each charging zone can be switched on or off using the switches (S1, S2, S3). Each charging zone also has a primary conductor section which is electrically connected in parallel to the respective switch (S1, S2, S3).

[0030] By closing the respective switch (S1, S2, S3), the respective charging area can be short-circuited and the current flowing in the primary conductor 4 is bypassed.

[0031] Since AC source 1 is a current source, the same current can be made available to all charging areas.

[0032] With each switch (S1, S2, S3) open, the current flows through the respective primary conductor section (5, 6, 7) laid in the charging area.

[0033] The primary conductor section 5 of a first charging area is again designed as an elongated conductor loop, preferably arranged on the ground or along a rail. Thus, a vehicle with a secondary winding to which a capacitor is connected in parallel and / or in series can be inductively powered. The resonant frequency of the resulting resonant circuit is essentially the same as the frequency of the alternating current impressed into the primary conductor 4. In this way, high efficiency in power transmission can be achieved even with large and / or fluctuating distances. The vehicle has electrical consumers, such as an electric traction drive and control electronics, which can be supplied from an energy storage device within the vehicle, which can be charged via the inductive power transmission. This also compensates for fluctuations in the transmitted power.

[0034] When the primary conductor section 5 is arranged on the ground, the secondary winding is preferably attached to the underside of the vehicle and the vehicle has a guidance device to move along a path defined by the elongated primary conductor section.

[0035] When the primary conductor section 5 is arranged along a rail, a rail vehicle can be supplied.

[0036] The system in which it is installed has a transport surface on the floor, on which not only the primary conductor section 5 is located, but also the additional charging areas 6 and 7. Each of these charging areas (6, 7) is less extensive than the primary conductor section 5. The primary conductor section assigned to each of these charging areas (6, 7) is configured as a primary winding (6, 7). Thus, a vehicle with a secondary winding on its underside can be inductively charged with high power. This is because the inductive coupling is higher in the charging areas (6, 7) than in the charging area with the elongated primary conductor section 5.

[0037] Each of the charging areas (5, 6, 7) has a capacitor (C1, C2, C3) connected in series to the respective primary conductor section (5, 6, 7) of the charging area (5, 6, 7), wherein the capacitor (C1, C2, C3) is dimensioned such that the resonant frequency of the resonant circuit formed from the inductance of the respective primary conductor section (5, 6, 7) and the capacitor connected in series (C1, C2, C3) is essentially equal to the frequency of the alternating current impressed into the primary conductor 4.

[0038] Each charging area (5, 6, 7) is assigned a sensor device 3, which is designed to detect a vehicle. The sensor device 3 provides an output signal that can be used to control the respective switch (S1, S2, S3). Therefore, if no vehicle is present, and consequently no inductive load such as a secondary winding, and thus no sufficient inductive coupling between the respective primary conductor section (5, 6, 7) and a secondary winding of a vehicle being charged, the switch (S1, S2, S3) remains closed, so that the charging area assigned to the respective sensor device 3 remains short-circuited and therefore de-energized.

[0039] However, if a vehicle is detected by the respective sensor device 3 and thus a secondary winding of the vehicle is inductively coupled to the primary conductor section 5, 6, or 7, the corresponding switch (S1, S2, S3) is opened and thus the respective associated primary conductor section (5, 6, 7) is energized.

[0040] Each sensor device 3 is connected to a data bus, which is also connected to the power supply unit comprising the AC power source 1. This allows data to be transmitted between the power supply unit and the sensor devices 3. In particular, the arrival of a vehicle in one of the charging areas can be reported to the power supply unit. The power required by the power supply unit can then be adjusted accordingly.

[0041] The sensor devices 3 can be supplied with power via the signal lines 2, which also include power supply lines or data bus lines that can also be used as power supply lines. In this way, the sensor devices 3 can be supplied with electrical power independently of the power impressed on the primary conductor 4. Therefore, if no vehicle is detectable in any of the charging areas (5, 6, 7), the current impressed on the primary conductor 4 can be switched off, thus saving energy. As soon as one of the sensor devices 3 detects a vehicle, the current is impressed on the primary conductor 4.

[0042] In a further embodiment of the invention, the sensor devices 3 are not supplied from the signal lines 2, but from the primary conductor 4, wherein each sensor device 3 has a secondary winding which is inductively coupled to the primary conductor 4. Thus, a reliable supply to the sensor devices 3 can be ensured regardless of the switch position (S1, S2, S3). However, even when no vehicles are present in the charging area, a current, i.e., alternating current, is still injected into the primary conductor section 4 by the power supply unit.

[0043] As in Figure 2 As shown, data transmission is also possible by modulating higher-frequency current signal components onto the alternating current impressed into the primary conductor 4 by the feed-in unit. Thus, the signal lines 2 of the Figure 1The feed-in unit has a data coupler 20, with which the data can be modulated onto the primary conductor 4 as higher-frequency current components. Likewise, each sensor device 3 is connected to a data coupler 21, with which the sensor signals can be modulated onto the primary conductor 4 as higher-frequency current components.

[0044] Furthermore, with each of the aforementioned data couplers, the modulated current components 20 and / or 21 can be demodulated, and thus the contained information can be decoded and forwarded to perform an action, such as switching off or reducing the imprinting of the lower frequency current component or the like.

[0045] In a further embodiment of the invention, the electrical supply is provided by the higher-frequency AC component, which transmits power and is modulated by the power supply unit. Thus, even when the medium-frequency AC component modulated by the power supply unit is switched off, the sensor devices are still supplied with power. However, a corresponding current component must be modulated by the power supply unit. If interruptions of this current component are also to be permitted, the respective data coupler 20 or 21 must have a correspondingly dimensioned energy storage device to buffer the electrical supply of the sensor devices 3 and the data couplers (20, 21).

[0046] When a vehicle enters a charging area (5, 6, 7) and is detected by the associated sensor device 3, a corresponding signal is transmitted via the associated data coupler 20 or 21 to the power supply unit with AC power source 1. Similarly, when a vehicle leaves the charging area (5, 6, 7), corresponding information is transmitted to the power supply unit. Depending on the number of vehicles currently detected, the power supply unit then controls the medium-frequency current component that determines the power output.

[0047] The AC power source 1 of the feed-in unit generates the medium-frequency current component, which has a frequency between 10 and 1000 kHz and a current strength of over 1 ampere, in particular between 10 and 100 amperes.

[0048] The signal line 2 preferably includes not only lines of the data bus but also low-voltage supply lines, in particular 24 volt lines.

[0049] The primary conductor 4 is designed as a current loop, which has a forward conductor and a return conductor. The primary conductor 4 is preferably arranged as an elongated conductor loop.

[0050] The primary conductor section 5 of this comprehensive charging area is also laid in an elongated shape. Reference symbol list

[0051] 1 AC power source 2 Signal line, in particular data bus and low-voltage supply lines, in particular 24-volt lines, 3 Sensor device 4 Primary conductor, in particular comprising the forward and return conductors of the primary conductor loop 5 Extended primary conductor section 6 Primary winding 7 Primary winding 20 Data coupler 21 Data coupler S1 Controllable switch, in particular circuit breaker S2 Controllable switch, in particular circuit breaker S3 Controllable switch, in particular circuit breaker C1 Capacitance C2 Capacitance C3 Capacitance

Claims

1. System for inductively transmitting electrical power to vehicles, wherein the system comprises an alternating current source (1) which supplies power to a plurality of stationarily arranged charging areas in series, wherein each charging area comprises a respective primary conductor section having a respective series-connected capacitor (C1, C2, C3), each primary conductor section having a controllable switch connected in parallel therewith, such that the primary conductor section is short-circuited when the switch is closed, and is supplied with power from a primary conductor (4), which is fed from the alternating current source (1), when the switch is open, wherein a parallel circuit formed of the respective primary conductor section of the charging area and the respective switch is assigned to each charging area, and these parallel circuits of the charging areas are connected in series and thus are supplied with power in series from the alternating current source (1) by means of the primary conductor (4), wherein the respective switch of the respective charging area can be controlled by a sensor device (3), wherein the sensor device (3) detects the presence of a vehicle in the charging area assigned to the sensor device (3), wherein the respective series-connected capacitor (C1, C2, C3) is dimensioned such that the resonant frequency of the resonant circuit formed of the inductor of the respective primary conductor section (5, 6, 7) and the respective series-connected capacitor (C1, C2, C3) corresponds to the frequency of the alternating current impressed in the primary conductor (4), characterized in that the sensor devices (3) are inductively supplied with power from the primary conductor (4), wherein to this end the respective sensor device (3) has in each case a secondary winding inductively coupled to the primary conductor (4), wherein the respective sensor device (3) has an energy store for buffering a temporarily interrupted power supply with electrical energy.

2. System according to claim 1, characterized in that the controllable switch is actuated, in particular opened or closed, as a function of the exceeding or undershooting of a threshold value of inductive coupling between the primary conductor section of the charging area and a secondary winding arranged on the vehicle.

3. System according to at least one of the preceding claims, characterized in that the sensor device (3) is connected for data transmission purposes by means of a communication channel, in particular a data transmission channel, to a feed-in unit, in particular an electrical device, which comprises the alternating current source (1).

4. System according to at least one of the preceding claims, characterized in that the communication channel is embodied by means of signal lines, wherein data can be transmitted from the feed-in unit to the sensor device (3) by means of the signal lines, in particular wherein the feed-in unit and the sensor device (3) are bus subscribers on a data bus.

5. System according to at least one of the preceding claims, characterized in that the communication channel comprises signals modulated onto the primary conductor (4), which are modulated onto the primary conductor (4) by the feed-in unit and / or by the sensor device (3), in particular wherein the frequency of the modulated signals is higher than the frequency of the alternating current impressed in the primary conductor (4) by the alternating current source (1), in particular which has a frequency between 10 and 1000 kHz.

6. Method for operating a system according to at least one of the preceding claims, characterized in that the respective sensor device (3) brings about the closing of the switch assigned to the respective sensor device (3) when no vehicle is detected, in particular in the charging area assigned to the sensor device (3), in particular when no vehicle is present, and in that the switch associated with the charging area is opened when a vehicle is detected in the charging area assigned to the sensor device (3).

7. Method according to claim 6, characterized in that the magnitude of the current impressed in the primary conductor (4) by the alternating current source (1) is controlled as a function of the number of closed switches of the system.