System for inductive energy transfer to a mobile device and method for operating an electrical device

Abstract

System for inductive energy transfer to a mobile device, wherein the system comprises an electrical device (5) with a display unit, which includes an inverter (1), wherein the voltage supplied at the AC-side terminal of the inverter (1) feeds the input of a four-terminal network, from the output of which a current is impressed into a primary conductor arrangement, wherein a signal electronics of the electrical device (5) comprises a means (3) for detecting the zero crossings of the current and for detecting the zero crossings of the voltage applied to the output of the four-terminal network, wherein the signal electronics comprise a means (4) for detecting the RMS or peak value of the current and for detecting the RMS or peak value of the voltage applied to the output of the four-terminal network, wherein the means (3, 4) are connected to a computing unit (2) which determines the actual value of the impedance of the primary conductor arrangement and the difference between the actual value and a setpoint value, wherein the computing unit (2) supplies a control signal representing the difference to the display unit, which displays the difference by means of a pointer whose rotational position and length are controlled by the control signal where the primary conductor arrangement consists of a series circuit of an matching capacitor, primary conductor sections and capacitors, wherein the primary conductor sections and capacitors are arranged alternately, wherein the display unit has a good range, wherein the limit of the good range corresponds to the setting limit of a controllable inductance of the handset.

Description

[0001] The invention relates to a system for inductive energy transfer to a mobile device and a method for operating an electrical device.

[0002] It is generally known to supply a handset of a system inductively, wherein a primary conductor arrangement is supplied with an alternating current on the stationary side of the system and a secondary winding is arranged on the underside of the handset, which can be inductively coupled to the primary conductor arrangement on the stationary side.

[0003] From US 2012 / 0 184 338 A1, a system for inductive energy transfer is known as the closest state of the art.

[0004] From DE 10 2006 022 223 A1 a protection module for a system for inductive energy transfer is known.

[0005] From the publication MFJ Enterprises, Inc.: “HF / VHF SWR Analyzer -Model MFJ-259C”, operating instructions, version C1, 2013, an electrical device with analog and digital display means became officially known on the Internet on 10.7.2018.

[0006] An analog display unit became known from the publication Hewlett-Packard Co.: “Rapid, Direct, Measurement of Complex Impedance in a Circuit / Methods of Measuring Impedance”, Hewlett-Packard Journal, issue: January 1967, via the internet on July 10, 2018.

[0007] The invention is therefore based on the objective of further developing a system for inductive energy transfer to a mobile device, wherein the system can be easily optimized and the function can be monitored.

[0008] According to the invention, the problem is solved in the system for inductive energy transfer to a mobile device according to the features specified in claim 1 and in the method for operating an electrical device according to the features specified in claim 8.

[0009] Key features of the invention for the inductive energy transfer system to a mobile device are that the system comprises an electrical device with a display unit, which includes an inverter, wherein the voltage provided at the AC-side connection of the inverter feeds the input of a four-terminal network, from whose output a current is impressed into a primary conductor arrangement. wherein a signal electronics of the electrical device includes a means for detecting the zero crossings of the current and for detecting the zero crossings of the voltage applied to the output of the four-terminal network, wherein the signal electronics comprise a means for detecting the RMS or peak value of the current and for detecting the RMS or peak value of the voltage applied to the output of the four-terminal network, wherein the means are connected to a computing unit which determines the actual value of the impedance of the primary conductor arrangement and the difference between the actual value and a target value, wherein the computing unit supplies a control signal representing the difference to the display unit, which displays the difference, in particular by means of a pointer whose rotational position and length are controlled by the control signal.

[0010] A key advantage is that the display indicates whether the system is tuned to resonance or not. It even shows the magnitude of the deviation, i.e., the difference from the target value. Additionally, the display can be used as a monitoring tool, as it changes when large metallic foreign objects enter the inductive transmission area. Furthermore, system monitoring is possible even with automated resonance adjustment. This allows for easy optimization and monitoring of a power supply unit for an inductive energy transfer system. In particular, the matching capacitance can be adjusted based on the display, thus optimizing the system's resonance tuning.

[0011] In an advantageous design, the display unit functions as an analog display device, In particular, the display unit also digitally displays the difference, thus functioning as a digital display device. A key advantage is that the deviation can be displayed very precisely quantitatively, allowing the value of the capacitance to be used as an adjustment capacitance to be calculated. Therefore, a single adjustment of the adjustment capacitance is sufficient.

[0012] According to the invention, the primary conductor arrangement consists of a series circuit of an matching capacitor, primary conductor sections and capacitors, In particular, the primary conductor sections and capacitors are arranged consecutively and / or alternately, especially for voltage reduction. It is advantageous that the primary conductor sections can be arranged segment by segment along the line, and that one of the capacitors can be placed between each pair of adjacent primary conductor sections. This avoids voltage spikes along the line. The matching capacitor is located at one pole of the output side of the four-terminal network.

[0013] According to the invention, the display unit has a "good" range, in particular wherein the boundary of the "good" range corresponds to the setpoint limit of a controllable inductor of the handset. It is advantageous that the display takes into account the setpoint range available on the secondary side. Thus, a display is arranged on the primary side that indicates the setpoint limit of a controllable inductor arranged on the secondary side, either with color and / or with lines.

[0014] In an advantageous embodiment, the computer unit of the electrical device's signal electronics controls the controllable semiconductor switches of the inverter. A key advantage is that the frequency of the input voltage at the four-terminal network is determined by the computer unit and is therefore known to it. This allows the frequency value to be additionally considered when determining the capacitance, which must be added to the matching capacitor.

[0015] In an advantageous embodiment, the four-terminal network has a capacitor arranged between the poles of its output terminal. and an inductor is arranged between a first pole of its input-side terminal, which is connected to the AC-side terminal of the inverter, and a first pole of its output-side terminal, In particular, the second pole of the input terminal and the second pole of the output terminal are directly electrically connected. An advantage of this is that the four-terminal network can be tuned to the frequency of the voltage supplying the four-terminal network to its input.

[0016] In an advantageous embodiment, the display unit shows a pointer whose rotation indicates the magnitude of the imaginary part of the impedance, i.e., reactance, and / or whose length represents the magnitude of the impedance. The advantage here is that the missing value can be displayed quickly and easily.

[0017] Key features of the invention are that the method is provided for operating an electrical device, wherein the alternating voltage provided by an inverter is supplied to the input side of a four-terminal network, the output side of which feeds a primary conductor arrangement, where the times of the zero crossings of the voltage applied to the output side and the times of the zero crossings of the current impressed from the output side into the primary conductor arrangement are recorded. and the RMS values ​​or peak values ​​of the voltage applied to the output side and the current impressed from the output side into the primary conductor arrangement are recorded, The impedance of the primary conductor arrangement is determined from the time points and the RMS values. where the difference between the impedance and a target impedance is determined, The difference, in particular the magnitude of the imaginary part of the difference, i.e., reactance, is displayed. A key advantage is that a high efficiency can be achieved with inductive transmission. Therefore, the system can be operated with high efficiency.

[0018] In an advantageous embodiment, the difference is indicated by a pointer whose length represents the magnitude of the difference and / or whose rotation indicates the imaginary part of the difference, i.e., reactance. The advantage here is that the deviation from the desired optimal value can be displayed quickly and easily.

[0019] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0020] The invention will now be explained in more detail with reference to schematic illustrations: In the Fig. Figure 1 schematically shows a system according to the invention for inductive energy transfer to a mobile device.

[0021] In this case, an electrical device 5 has an analog display 6 and / or a digital display 7.

[0022] The electrical device 5 also includes an inverter which provides an alternating voltage U_a that supplies the two input terminals of a four-terminal network, in particular a gyrator. The inverter 1 exhibits voltage source-like behavior.

[0023] The four-terminal network exhibits current source-like behavior at its two output terminals.

[0024] The frequency of the alternating voltage U_a provided by the inverter is as constant as possible.

[0025] The four-terminal network is, according to the exemplary embodiment, according to Fig. 1. Composed of an inductance L_g and a capacitance C_g. The inductance L_g is arranged between a first of the two input-side terminals and a first of the two output-side terminals.

[0026] The capacitance C_g is located between the two output terminals of the four-terminal network.

[0027] The second of the input terminals is directly connected to the second of the output terminals of the four-pole network.

[0028] The inductance L_g and the capacitance C_g are dimensioned such that the four-terminal network is resonantly tuned to the frequency of the alternating voltage U_a provided by the inverter.

[0029] Inverter 1 has power semiconductors arranged in half-bridges, which are controlled by pulse-width modulated control signals from a signal electronics unit, in particular computer unit 2 of the signal electronics. Thus, the signal electronics unit 2, in particular computer unit 2 of the signal electronics, also specifies the frequency of the alternating voltage provided by the inverter.

[0030] Furthermore, the voltage V and the current I supplied by the four-terminal network are measured. A primary conductor arrangement is supplied from the output side; this arrangement comprises a primary line laid out over a long distance within the system, with a capacitor provided at each section of the line for voltage reduction and balancing.

[0031] The primary conductor arrangement is a series connection of primary conductor sections, each having an inductance (L_L1, L_L2, ..., L_LN), and capacitors (C_L1, L_C_L2, ..., C_LN) arranged between the primary conductor sections, whereby high voltages can be avoided by this alternating series connection.

[0032] Thus, the primary conductor laid along the route of the handset is divided into primary conductor sections, between which the capacitors (C_L1, L_C_L2, ..., C_LN) are arranged. The resulting line impedance jX_L, obtained from the capacitors (C_L1, L_C_L2, ..., C_LN) and inductances (L_L1, L_L2, ..., L_LN) while neglecting the ohmic resistance, is matched by an matching capacitor jX_Korr, which is connected in series with the line impedance jX_L and consists of pure capacitance, thus enabling additional adjustment to the frequency of the impressed alternating current.

[0033] The series circuit of matching capacitance jX_Korr and line impedance jX_L is supplied by the voltage U_cg provided at the capacitance C_g of the four-terminal network, so that a current I_L is impressed into the series circuit of matching capacitance jX_Korr and line impedance jX_L.

[0034] The signal electronics of the electrical device 5 include a means 3 for detecting the zero crossings of the supplied voltage U_cg and the current I_L. Thus, the respective times of the zero crossings are recorded in the time series of the values ​​of these two measured quantities (I_L, U_cg), and the phase shift between the voltage U_cg and current I_L is determined from this by a computer unit 2 of the signal electronics. Furthermore, the time series of the measured values ​​of the voltage U_cg and current I_L are fed to a means 4 for determining the respective RMS value. The RMS values, as well as the times of the zero crossings, are fed to the computer unit 2. In this way, the amplitude and phase shift of current I_L and voltage U_cg are determined.

[0035] The electrical device 5 has a display unit with which the deviation from the resonant tuning of the primary conductor arrangement can be shown. Preferably, an analog display is implemented. A pointer is used, and the displayed values ​​are divided into weighted value ranges by means of a scale. In particular, the area around the optimal tuning to resonance is designated as the "good range," for example, with a first color, such as green, and further apart areas with a different color, such as orange and / or red.

[0036] Thus, the need to change the adjustment capacity jX_Korr is easily recognizable.

[0037] Additionally, a digital display 7 is also installed on the electrical appliance.

[0038] In one version, the pointer, with a constant length, only indicates the reactance deviation from a predefined target value. Thus, the pointer's angle indicates the reactance deviation. In another version, the pointer length is additionally displayed, corresponding to the magnitude of the difference between the measured impedance and a predefined target impedance.

[0039] The electrical device 5 includes not only the signal electronics and the display unit, but also the inverter 1 including the four-pole connector.

[0040] In this way, the electrical device 5 according to the invention is designed as a feed-in device for the primary conductor arrangement of a system for inductive power transfer to a mobile device, and the adjustment of the matching capacitance jX_Korr can be performed manually depending on the display or, in a further development, automatically. With automated adjustment, the display serves for quality control and for the detection of disturbances, such as the ingress of large metallic objects into the area of ​​inductive transmission.

[0041] The handset has a secondary winding on its underside, which can be inductively coupled to a respective primary conductor section. A capacitor from the handset is connected in parallel and / or in series with the secondary winding, the capacitor being dimensioned such that the resonant frequency of the resulting resonant circuit corresponds to the frequency of the current impressed into the primary conductor arrangement.

[0042] Preferably, a controllable inductance of the secondary winding is connected in parallel or in series within the resonant circuit, so that the resonant frequency on the secondary side can be finely tuned to the frequency impressed on the primary side.

[0043] In further embodiments of the invention, instead of the four-terminal network, a Fig. 1 Another four-terminal network acting as a gyrator is used, so that the input-side voltage source-like behavior is again converted into an output-side current source-like behavior by tuning the inductance and capacitance to resonance.

[0044] In a further embodiment according to the invention, the peak value or a corresponding value from the mean 4 is determined and used instead of the RMS value.

[0045] In a further embodiment of the invention, the matching capacitance jX_Korr is controllable, thus enabling automated adjustment. For this purpose, electronic semiconductor switches are provided, allowing additional capacitances to be connected in parallel and / or in series with the matching capacitance jX_Korr. This enables at least a staged adjustment to the resonance condition. By means of this controllable inductance, a predetermined frequency range can be set as the resonance frequency, whereby the good range indicated on the primary side in the analog display 6 is adapted to this frequency range. Reference symbol list 1 inverter 2 computer units 3 methods for detecting the zero crossing 4. Means of determining the effective value 5 Electrical appliance 6 Display, especially analog 7 Display, especially digital U_a Voltage at the AC-side connection of the inverter 1 I_a Current from the AC-side connection of the inverter 1 L_g Inductance of the four-terminal network C_g capacitance of the four-terminal network U_cg voltage at the output terminal of the gyrator jX_Korr adjustment capacity jX_L line impedance R_L Last

Claims

[1] System for inductive power transfer to a mobile device, wherein the system comprises an electrical device (5) with a display unit, which includes an inverter (1), wherein the voltage supplied at the AC-side terminal of the inverter (1) feeds the input of a four-terminal network, from the output of which a current is impressed into a primary conductor arrangement, wherein a signal electronics of the electrical device (5) comprises a means (3) for detecting the zero crossings of the current and for detecting the zero crossings of the voltage applied to the output of the four-terminal network, wherein the signal electronics comprise a means (4) for detecting the RMS or peak value of the current and for detecting the RMS or peak value of the voltage applied to the output of the four-terminal network, wherein the means (3, 4) are connected to a computing unit (2) which determines the actual value of the impedance of the primary conductor arrangement and the difference between the actual value and a setpoint value, wherein the computing unit (2) supplies a control signal representing the difference to the display unit, which displays the difference by means of a pointer whose rotational position and length are controlled by the control signal where the primary conductor arrangement consists of a series circuit of an matching capacitor, primary conductor sections and capacitors, wherein the primary conductor sections and capacitors are arranged alternately, wherein the display unit has a good range, wherein the limit of the good range corresponds to the setting limit of a controllable inductance of the handset. [2] System according to claim 1, characterized by that the display unit functions as an analog display device. [3] System according to at least one of the preceding claims, characterized by , that the computer unit (2) of the signal electronics of the electrical device (5) controls the controllable semiconductor switches of the inverter (1). [4] System according to at least one of the preceding claims, characterized by , that The four-terminal network has a capacitance arranged between the poles of its output terminal. and an inductor is arranged between a first pole of its input-side terminal, which is connected to the AC-side terminal of the inverter (1), and a first pole of its output-side terminal. [5] System according to at least one of the preceding claims, characterized by , that the display unit shows a pointer whose rotational position indicates the magnitude of the imaginary part of the impedance, i.e., reactance. [6] System according to claim 5, characterized by, that the length of the displayed pointer represents the magnitude of the impedance. [7] System according to at least one of the preceding claims, characterized by , that the handset has a secondary winding on its underside which can be inductively coupled to a respective primary conductor section of the primary conductor arrangement. [8] Method for operating an electrical appliance (5) for a system according to at least one of the preceding claims, wherein the alternating voltage provided by an inverter (1) is supplied to the input side of a four-terminal network, the output side of which feeds a primary conductor arrangement, where the times of the zero crossings of the voltage applied to the output side and The times of the zero crossings of the current impressed from the output side into the primary conductor arrangement are recorded. and the RMS values ​​or peak values ​​of the voltage applied to the output side and the current impressed from the output side into the primary conductor arrangement are recorded, the impedance of the primary conductor arrangement is determined from the time points and the RMS values, where the difference between the impedance and a target impedance is determined, where the difference is displayed, wherein the primary conductor arrangement consists of a series connection of an matching capacitor, primary conductor sections and capacitors, wherein the primary conductor sections and capacitors are arranged alternately, wherein the display unit has a good range, wherein the limit of the good range corresponds to the setting limit of a controllable inductance of the handset. [9] Method according to claim 8, characterized by, that the difference is indicated by a pointer whose length indicates the magnitude of the difference and / or whose rotational position indicates the imaginary part of the difference, i.e., reactance. [10] Method according to claim 8 or 9, characterized by , that the difference is indicated by a pointer whose rotational position indicates the imaginary part of the difference, i.e., reactance.

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