CHARGING DEVICE

Abstract

A charging device includes a passive auxiliary circuit and a rectifier which is connected downstream of the auxiliary circuit. The passive auxiliary circuit includes input nodes and output nodes. Between the input node and the output nodes, two impedances are connected. Here, an imaginary component of the first impedance has a positive non-zero value and an imaginary component of the second impedance a negative non-zero value or vice versa.

Claims

1. A charging device for the wireless reception of energy, the charging device comprising: a passive auxiliary circuit; and a rectifier connected downstream of the auxiliary circuit, wherein the passive auxiliary circuit comprises a first and a second input node and a first, a second, and a third output node, wherein between the first input node and the first output node a first impedance is connected and between the first input node and the second output node a second impedance is connected, and wherein an imaginary component of the first impedance has a positive non-zero value and an imaginary component of the second impedance has a negative non-zero value or vice versa.

2. The charging device according to claim 1, wherein the positive or negative value of the imaginary component of the first impedance and the negative or positive value of the imaginary component of the second impedance are equal in the amount.

3. The charging device according to claim 1, wherein: between the second input node and the third output node of the auxiliary circuit a third impedance is connected, and an imaginary component of the third impedance has a positive or negative non-zero value or in a resonance case a value equal to zero.

4. The charging device according to claim 1, wherein: the respective impedance is formed by a coil, or the respective impedance is formed by a coil and a capacitor which are connected in series.

5. The charging device according to claim 1, wherein: the charging device comprises a commutation circuit which is connected between the passive auxiliary circuit and the rectifier, the commutation circuit comprises at least one commutation capacitor, and the at least one commutation capacitor is connected between two of the respective output nodes of the auxiliary circuit.

6. The charging device according to claim 1, wherein: the rectifier comprises a first, a second, and a third input node and a first and a second output node, and the respective input node of the rectifier is connected in each case to the respective output node of the auxiliary circuit.

7. The charging device according to claim 6, wherein: the rectifier comprises three diode half bridges, and the respective diode half bridge in each case is connected between one of the respective input nodes of the rectifier and two of the respective output nodes of the rectifier.

8. The charging device according to claim 6, wherein: the rectifier comprises a compensation capacitor, and the compensation capacitor is connected between the output nodes of the rectifier.

9. The charging device according to claim 1, wherein: the charging device comprises a secondary charging coil for the wireless reception of energy and a reactive power compensation network for offsetting reactive power, and the charging coil is connected upstream of the reactive power compensation network and the reactive power compensation network is connected upstream of the auxiliary circuit.

10. The charging device according to claim 1, wherein: the charging device comprises a battery for storing energy received, and the battery is connected downstream of the rectifier.

11. The charging device according to claim 1, wherein the charging device is provided for the inductive charging of motor vehicles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The disclosure will now be described with reference to the drawings wherein:

[0024] FIG. 1 shows a circuit diagram of a charging device according to the disclosure;

[0025] FIG. 2 shows a comparative diagram of a real component of an input impedance in the respective charging device of distinct configuration as a function of a battery voltage of a battery;

[0026] FIG. 3 shows a comparative diagram of an imaginary component of the input impedance in the respective charging device of different configuration as a function of the battery voltage of the battery;

[0027] FIGS. 4 to 7 show diagrams with a time profile of two component currents and of two component voltages in the charging device according to the disclosure with different battery voltages;

[0028] FIGS. 8 and 9 show comparative diagrams of two component currents in the respective charging device configured differently as a function of the battery voltage of the battery;

[0029] FIG. 10 shows a diagram of a phase angle difference between two component currents in the respective charging device configured differently as a function of the battery voltage of the battery; and

[0030] FIGS. 11 and 12 show comparative diagrams with a time profile of two component currents and two component voltages in the respective charging device configured differently.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0031] FIG.1 shows a circuit diagram of a charging device 1 according to the disclosure. Here, the charging device 1 includes an auxiliary circuit 2, a commutation circuit 3 and a rectifier 4. Here, the commutation circuit 3 is connected downstream of the auxiliary circuit 2 and upstream of the rectifier 4. In addition, the charging device 1 comprises a battery Rb which is connected downstream of the rectifier 4.

[0032] The auxiliary circuit 2 is passive. The auxiliary circuit 2 comprises exactly two input nodes—here a first and a second input node H-EK1 and H-EK2—and exactly three output nodes—here a first, a second and a third output node H-AK1, H-AK2 and H-AK3. Between the first input node H-EK1 and the first output node H-AK1 a first impedance with a coil Lrec1 and a capacitor Crec1 is connected. Here, the first impedance comprises an imaginary component X1. Between the first input node H-EK1 and the second output node H-AK2 a second impedance with a coil Lrec2 and a capacitor Crec2 is connected. Here, the second impedance comprises an imaginary component X2. Between the second input node H-EK2 and the third output node H-AK3 a third impedance with a coil Lrec3 and a capacitor Crec3 is connected. Here, the third impedance comprises an imaginary component X3.

[0033] The commutation circuit 3 is connected downstream of the auxiliary circuit 2 and comprises a first, a second and a third commutation capacitor Cc1, Cc2 and Cc3. The first commutation capacitor Ccl is connected between the first output node H-AK1 and the second output node H-AK2 of the auxiliary circuit 2. The second commutation capacitor Cc2 is connected between the second output node H-AK2 and the third output node H-AK3 of the auxiliary circuit 2. The third commutation capacitor Cc3 is connected between the first output node H-AK1 and the third output node H-AK3 of the auxiliary circuit 2.

[0034] The rectifier 4 comprises a first, a second and a third input node G-EK1, G-EK2, G-EK3. The input nodes G-EK1, G-EK2, G-EK3 coincide with the respective output nodes H-AK1, H-AK2 and H-AK3 of the auxiliary circuit 2. In addition, the rectifier 4 comprises a first and a second output node G-AK1 and G-AK2. In addition, the rectifier 4 comprises six diodes D1, D2, D3, D4, D5, D6 which are connected as diode half bridges each between the input nodes H-EK1, H-EK2, H-EK3 of the rectifier 4 and the output nodes G-AK1, G-AK2 of the rectifier 4. In addition, the rectifier 4 comprises a compensation capacitor C0, which is connected between the output nodes G-AK1 and G-AK2 of the rectifier 4. The compensation capacitor C0 is connected downstream of the diode half bridges. The battery Rb between the output nodes G-AK1 and G-AK2 of the rectifier 4 is connected downstream of the compensation capacitor C0.

[0035] Here, the charging device 1 comprises a secondary charging coil and a reactive power compensation network, both of which are not shown here. The secondary charging coil is connected upstream of the reactive power compensation network and the reactive power compensation network is connected upstream of the auxiliary circuit 2. Here, a coil alternating voltage is initiated in the secondary charging coil and an alternating voltage UAC is present at the input nodes H-EK1 and H-EK2 of the auxiliary circuit 2. Because of the reactive power compensation network connected upstream, the coil alternating voltage and the alternating voltage UAC are not identical. Here, the charging device 1 has an input impedance with a real component Rin and with an imaginary component Xin. In the auxiliary circuit 2 of the charging device 1 a first component current irec1 flows between the first input node H-EK1 and the first output node H-AK1 and a second component current irec2 flows between the first input node H-EK1 and the second output node H-AK2. A first component voltage urecl drops between the output nodes H-AK1 and H-AK3 and a second component voltage urec2 drops between the output nodes H-AK2 and H-AK3. On the battery Rb, the battery current lb flows and a battery voltage Ub drops.

[0036] In the charging device 1, the imaginary component X1 of the first impedance has a positive value and the imaginary component X2 of the second impedance a negative value or vice versa. This leads to a phase shift between the first component current irecl and the second component current irec2. Here, the mentioned phase shift varies with the battery voltage Ub. Because of this, the variation range of the real component Rin of the input impedance with the rising battery voltage Ub is greatly compressed. Apart from this, the imaginary component Xin of the input impedance can be reduced through the commutation capacitors Cc1, Cc2 and Cc3 of the commutation circuit 3. The commutation circuit 3 leads to a symmetrical loading of the branches between the input nodes H-EK1 and the output nodes H-AK1, H-AK2. The commutation circuit 3 is optional. Advantageously, the imaginary component X1 of the first impedance and the imaginary component X2 of the second impedance can be the same in the amount. The imaginary component X3 of the third impedance can advantageously have a value equal to zero. Accordingly, the coil Lrec3 and the capacitor Crec3 can be omitted.

[0037] The advantage of the charging device 1 according to the disclosure lies in the optimized component selection as a result of which costs, weight and installation space can be saved.

[0038] In FIGS. 2 to 10, characteristics of the charging device according to the disclosure are illustrated on the basis of a simulation. The values of the respective imaginary components X1, X2, X3 of the respective impedances defined in the simulation are based on a given fixed operating frequency of 85 kHz. The following exemplary values were employed for the simulation:

[0039] Lrec1=19.48 μH UAC=449.7 V

[0040] Lrec2=19.27 Mh P to 10,000 W

[0041] Lrec3=18.12 μH Ub=280V to 450V

[0042] Crec1=1817.9 nF Cc1=137 pF

[0043] Crec2=90.89 nF Cc2=263 pF

[0044] Crec3=193.48 nF Cc3=415 pF

[0045] FIG. 2 shows a comparative diagram of the real component Rin of the input impedance in the charging device 1 as a function of the battery voltage Ub of the battery Rb. The profile of the real component Rin of the input impedance in the charging device 1 according to FIG. 1 with the commutation circuit 3 is shown with a continuous line. Here, the profile of the real component Rin of the input impedance in the charging device 1 according to FIG. 1 without the commutation circuit 3 is shown with a dashed line.

[0046] FIG. 3 shows a comparative diagram of the imaginary component Xin of the input impedance in the charging device 1 as a function of the battery voltage Ub of the battery Rb. Here, the profile of the imaginary component Xin of the input impedance in the charging device 1 according to FIG. 1 with the commutation circuit 3 is shown with a continuous line. Here, the profile of the imaginary component Xin of the input impedance in the charging device 1 according to FIG. 1 without the commutation circuit 3 is shown with a dashed line.

[0047] FIG. 4 shows a diagram with a time profile of the component currents irec1 and irec2 and of the two component voltages urecl and urec2 in the charging device 1 according to the disclosure with the battery voltage Ub of 280V without the commutation circuit 3. In the upper part diagram, the component current irec1 is plotted with the dotted line and the component voltage urec1 with the continuous line. In the lower part diagram, the component current irec2 is plotted with the dotted line and the component voltage urec2 with the continuous line.

[0048] FIG. 5 shows a diagram with a time profile of the component currents irec1 and irec2 and of the two component voltages urec1 and urec2 in the charging device 1 according to the disclosure with the battery voltage Ub of 350V without the commutation circuit 3. In the upper part diagram, the component current irecl is plotted with the dotted line and the component voltage urec1 with the continuous line. In the lower part diagram, the component current irec2 is plotted with the dotted line and the component voltage urec2 with the continuous line.

[0049] FIG. 6 shows a diagram with a time profile of the component currents irec1 and irec2 and of the component voltages urec1 and urec2 in the charging device 1 according to the disclosure with the battery voltage Ub of 400V without the commutation circuit 3. In the upper part diagram, the component current irec1 is plotted with the dotted line and the component voltage urec1 with the continuous line. In the lower part diagram, the component current irec2 is plotted with the dotted line and the component voltage urec2 with the continuous line.

[0050] FIG. 7 shows a diagram with a time profile of the component currents irec1 and irec2 and of the two component voltages urecl and urec2 in the charging device 1 according to the disclosure with the battery voltage Ub of 450V without the commutation circuit 3. In the upper part diagram, the component current irecl is plotted with the dotted line and the component voltage urec1 with the continuous line. In the lower part diagram, the component current irec2 is plotted with the dotted line and the component voltage urec2 with the continuous line.

[0051] From FIGS. 4 to 7, it is evident that there is a phase angle difference between the component currents irec1 and irec2 and that the phase angle θ decreases with the rising battery voltage Ub. In the charging device 1 according to the disclosure—for example in FIG. 4—there is a timespan in which the component voltages urec1 and urec2 are equal to zero. There is thus a freewheel. The reason for this is that the moment of the commutation for the diode half bridges of the rectifier 4 in the charging device 1 according to the disclosure is different.

[0052] FIG. 8 shows a comparative diagram of effective values of the component currents irec1 and irec2 in the charging device 1 from FIG. 1 without the commutation circuit 3 as a function of the battery voltage Ub of the battery Rb. Here, the profile of the first component current irec1 is shown with a continuous line and the profile of the second component current irec2 with the dashed line.

[0053] FIG. 9 shows a comparative diagram of effective values of the component currents irec1 and irec2 in the charging device 1 from FIG. 1 with the commutation circuit 3 as a function of the battery voltage Ub of the battery Rb. Here, the profile of the first component current irecl is shown with a continuous line and the profile of the second component current irec2 with a dashed line.

[0054] FIG. 10 shows a diagram of a phase angle difference between the component currents irec1 and irec2 in the charging device 1 from FIG. 1 with and without the commutation circuit 3 as a function of the battery voltage Ub of the battery Rb. Here, the phase angle difference with the commutation circuit 3 is shown with a continuous line and the phase angle difference without the commutation circuit 3 with a dashed line.

[0055] FIG. 11 shows a comparative diagram with a time profile of the two component currents irecl and irec2 in the charging device 1 according to the disclosure with the battery voltage Ub of 450V with the commutation circuit 3. Here, the component current irec1 is plotted with the continuous line and the component current irec2 with the dotted line.

[0056] FIG. 12 shows a comparative diagram with a time profile of the two component currents irec1 and irec2 in the charging device 1 according to the disclosure with the battery voltage Ub of 450V without the commutation circuit 3. Here, the component current irec1 is plotted with the continuous line and the component current irec2 with the dotted line.

[0057] It is understood that the foregoing description is that of the exemplary embodiments of the disclosure and that various changes and modifications may be made thereto without departing from the spirit and scope of the disclosure as defined in the appended claims.