Tandem AC / DC converter with intermediate circuit voltage adaptation converter and LLC output converter and spread spectrum operation by means of modulation of intermediate circuit voltage

Abstract

According to a first aspect, a device (200-1) for a stable DC voltage supply (220) is provided. The device (200-1) comprises: an adapter converter (206), which is or can be connected in an electrically conductive manner to the DC voltage source (202, 204) or the AC voltage source (202) on the input side of the adapter converter (206); and an LLC converter (100), the input side of which is connected or can be connected to the output side of the adapter converter (206) in an electrically conductive manner. The LLC converter (100) is designed to provide a stable DC voltage supply (220) on the output side, wherein the DC voltage of the stable DC voltage supply (220) on the output side is a function of the switching frequency of the LLC converter (100). The adapter converter (206) comprises a control unit (208) which is configured to superimpose an output DC voltage of the adapter converter (206) with an AC voltage (218). The amplitude of the superimposed AC voltage (218) is smaller than that of the output DC voltage. The frequency of the superimposed alternating voltage (218) is less than the switching frequency of the LLC converter (100).

Description

Technical Field

[0001] The present invention relates to a technology for realizing a stable DC voltage supply using an LLC converter (also referred to as LLC converter in English and professional terms). The present invention particularly includes a device and a method in which a time clock jitter (professional term: jitter "Jitter") of the LLC converter is generated in order to avoid narrowband spikes in the spectrum of the LLC converter. Background Art

[0002] LLC converters are increasingly used in modern devices for energy supply (also referred to in English and technical terms as power supplies), since LLC converters can achieve very high efficiencies and small overall dimensions. In the case of LLC converters, the output voltage is varied by varying the switching frequency of the LLC converter. If the LLC converter is supplied with a stable, fixed input voltage (especially with a small voltage ripple), this results in a defined switching frequency of the LLC converter.

[0003] In LLC converters fed by direct current voltage (also known in technical terms as “direct current” voltage, DC voltage for short) or three-phase (also known in technical terms as 3-phase) alternating current voltage (also known in technical terms as “alternating current” voltage, AC voltage for short) (possibly with an additional step-up or step-down adaptor between the DC or 3-phase input voltage and the LLC converter), the voltage across the LLC converter is usually so stable that the switching frequency of the LLC converter fluctuates only slightly. There is actually a fixed frequency.

[0004] Regarding the interference radiation conducted by the wires at the input and output of such LLC converters, this causes the switching frequency of the LLC converter and its harmonics to appear in the frequency spectrum as narrowband peaks. Since the frequency changes are very small, the average value of these peaks (also known as the Average value in professional terms) is almost as high as their quasi-peak value (also known as the Quasi-Peak value in professional terms). Although there is a limit value for the quasi-peak value that is significantly higher than the average value, for example, a limit value of about 10 decibels (10 dB) or more, such strong electromagnetic compatibility (EMC) measures must be taken so that even the quasi-peak value is reduced below the limit value of the average value. This is very costly and disadvantageous in terms of equipment costs and equipment size.

[0005] The conventional characteristics described above occur especially in the case of DC or 3-phase device input voltages. In the case of single-phase (1-phase) input voltages, the input voltage on the LLC converter is usually less stable, e.g. with a large voltage ripple, and the switching frequency of the LLC converter is therefore also more variable, which is why problems do not occur or occur to a lesser extent here.

[0006] If the frequency variation of the LLC converter is larger, lower quasi-peak values ​​and average values ​​will be generated, because the energy will be distributed over a larger frequency range. In addition, the average value will be significantly lower than the quasi-peak value, and therefore less expenditure on EMC measures will be required. In other conventional converter types (such as flyback converters), this is achieved by targeted time clock jittering (technical term: jitter) of the switching frequency in order to thus generate a wider frequency spectrum. Since the switching frequency is the regulating variable of the output voltage in the LLC converter, this cannot be converted in a simulated manner in a stable DC voltage supply. Changing the switching frequency of the LLC converter will interfere with the output voltage. Summary of the invention

[0007] The object of the present invention is therefore to provide a technique for realizing a stable DC voltage supply by means of an LLC converter, which is fed by a low-ripple input voltage, in particular a DC voltage or a three-phase AC voltage connected to a rectifier. Alternatively or additionally, the object of the present invention is to avoid narrowband peaks in the spectrum of the LLC converter in the case of a low-ripple input voltage. Furthermore, alternatively or additionally, the object is to generate a time clock jitter (technical term: jitter) of the switching frequency of the LLC converter without disturbing the output voltage of the LLC converter.

[0008] This object or these objects are achieved by the features of the independent claim. Advantageous embodiments and advantageous developments of the invention are given in the dependent claims.

[0009] Embodiments of the present invention are described below, in part with reference to the accompanying drawings.

[0010] According to a first aspect, a device for a stable DC voltage supply is provided. The device includes an adaptive converter, which is conductively connected or connectable to a DC voltage source or an AC voltage source on the input side of the adaptive converter. The device also includes an LLC converter, which is conductively connected or connectable to the output side of the adaptive converter on the input side. The LLC converter is configured to provide a stable DC voltage supply on the output side. The DC voltage of the stable DC voltage supply on the output side is a function of the switching frequency of the LLC converter. The adaptive converter includes a control unit (English and professional terminology: controller "Controller"), which is configured to superimpose the output DC voltage (e.g., low-voltage ripple) of the adaptive converter with the AC voltage. The amplitude of the superimposed AC voltage is less than the output DC voltage of the adaptive converter. The frequency of the superimposed AC voltage is less than the switching frequency of the LLC converter.

[0011] The LLC converter may be a resonant converter. Alternatively or additionally, the LLC converter may include a transformer on the output side. The primary side of the transformer may be the primary inductor (L P , i.e. a larger output inductor). The leakage inductance of the transformer (L S ) can be the coupled inductor of the LLC converter.

[0012] Alternatively or additionally, the LLC converter may comprise a rectifier on the output side.The DC voltage of the output-side stabilized DC voltage supply (which is a function of the switching frequency of the LLC converter) may be this rectified (and optionally capacitively smoothed) DC voltage.

[0013] The LLC converter may include a switching unit (also referred to as a regulator). The switching unit of the LLC converter may generate a switching frequency of the LLC converter.

[0014] A stable DC voltage supply on the output side of the LLC converter may depend on the switching frequency of the switching units of the LLC converter.

[0015] The adapter converter may include a boost converter (also known as a boost converter; English: Boost Converter, also known as Step-Up Converter), a buck converter (also known as a buck converter; English: Buck Converter, also known as Step-Down Converter) and / or a boost-buck converter (also known as a boost / buck converter; English: Buck Boost Converter).

[0016] Alternatively or additionally, the adapted converter may include a flyback converter (English: Flyback Converter), a SEPIC converter (SEPIC is the abbreviation of Single Ended Primary Inductance Converter), a flow converter and / or a bridge converter. In addition, alternatively or additionally, a flyback converter (English: Flyback Converter) and / or a SEPIC converter can be classified as a boost-buck converter. In addition, alternatively or additionally, the flow converter and / or the bridge converter may be implemented and / or classified as a buck converter or a boost-buck converter. For example, by a transformer in the circuit of the flow converter and / or the bridge converter, the output voltage may be higher than the input voltage.

[0017] Furthermore, alternatively or additionally, the adaptor can include a bridgeless rectifier, for example a Vienna rectifier. For example, the bridgeless rectifier can be connected or connectable to an AC voltage source on the input side. The adaptor, which includes a bridgeless rectifier, can provide, for example, an adjustable output DC voltage.

[0018] For example, the adaptor converter may comprise a rectifier, in particular a bridgeless one, for the AC voltage source and / or the output voltage of the adaptor converter and / or the output voltage of the device comprising an LLC converter in the high power range, in particular greater than or equal to one kilowatt (1 kW). Alternatively or additionally, in the case of high powers, power factor correction (PFC) may be important and / or applied. For example, conventional rectifiers connected in series or in series between the AC voltage source and the input side of the adaptor converter are not suitable for high-power PFC.

[0019] The DC voltage source on the input side of the adaptive converter can comprise a rectification of a three-phase AC voltage.

[0020] The frequency of the superimposed AC voltage may be a low-frequency AC voltage. Alternatively or additionally, the frequency of the superimposed AC voltage is (particularly to a large extent or multiple times, for example at least an integer multiple times) smaller than the switching frequency of the LLC converter and / or (particularly to a large extent, for example an integer multiple times) smaller than the bandwidth of the switching unit (i.e., the regulator) of the LLC converter. If the frequency of the superimposed AC voltage is (particularly to a large extent or multiple times, for example at least an integer multiple times) smaller than the switching frequency of the LLC converter and (particularly to a large extent or multiple times, for example at least an integer multiple times) smaller than the bandwidth of the switching unit of the LLC converter, the output voltage can be kept stable in particular.

[0021] The amplitude of the (eg superimposed) alternating voltage may be the maximum absolute value of the (eg superimposed) alternating voltage.

[0022] A time clock jitter (also called frequency jitter) of the LLC converter can be generated by means of the superimposed AC voltage.

[0023] The input voltage of the LLC converter can be varied (also referred to as controlled) by means of a (especially small) superimposed AC voltage. Alternatively or additionally, the frequency of the LLC converter and its jitters are not necessarily visible only at the input voltage. The clock frequency of the LLC converter can be observable and / or detectable in the input current and / or the output current (and the voltage ripple generated thereby, for example, on the input and output sides of the LLC converter) and / or in the transformer voltage of the LLC converter.

[0024] By means of a changing input voltage, the LLC converter can or must adjust its frequency (for example by means of a switching unit, also referred to as a regulator). Jitter can therefore be produced and / or generated directly in the LLC converter.

[0025] For example, an LLC converter may have an input DC voltage of 800 V (also denoted by Vdc for DC voltage), an output DC voltage of 24 V (also referred to as Vdc) and a switching frequency of 95 kHz. The input voltage may be increased to, for example, 815 V (also referred to as Vdc) by means of a superimposed AC voltage (for example, in the positive phase of the AC voltage). In order to keep the output voltage at 24 V (also referred to as Vdc), the switching unit (also referred to as the regulator) of the LLC converter in this embodiment increases the switching frequency to, for example, 100 kHz. The input voltage may then be reduced to 785 V (also referred to as Vdc) (for example, in the negative phase of the AC voltage). In order to keep the output voltage at 24 V (also referred to as Vdc), the switching unit (also referred to as the regulator) of the LLC converter in this embodiment reduces the switching frequency to, for example, 90 kHz.

[0026] The switching frequency of the LLC converter is visible in the input current and / or the output current of the LLC converter.Alternatively or additionally, the switching frequency of the LLC converter is visible in the voltage at the transformer of the LLC converter.

[0027] With regard to electromagnetic compatibility (EMC), the switching frequency of the LLC converter may be observable (also referred to as detectable or visible) in (e.g., the entire) device including the LLC converter. The switching frequency of the LLC converter may be transmitted to (e.g., all possible) locations, for example, through parasitic coupling, so that the switching frequency of the LLC converter may be detected at both the input side and the output side of the device.

[0028] The switching unit of the LLC converter may be configured to change a switching frequency in response to an AC voltage superimposed on an input DC voltage.

[0029] The output DC voltage of the adaptation converter may correspond to the input DC voltage of the LLC converter.

[0030] By jittering the time clock of the LLC converter, high peak values ​​can be avoided, suppressed and / or spread out in the frequency range of the LLC converter. Alternatively or additionally, high peak values ​​in the frequency range of the LLC converter can be distributed and / or eliminated over a frequency range that is spread out by the frequency of the superimposed AC voltage, rather than in a narrow frequency range of the switching frequency.

[0031] By means of the superimposed AC voltage, changes in the magnitude of the DC voltage on the input side of the LLC converter and changes in the switching frequency can be compensated in the switching unit of the LLC converter, so that the DC voltage supply on the output side of the LLC converter is stable.

[0032] By means of the device, an improved electromagnetic compatibility of an LLC converter can be achieved with simple components and / or with a small overall size.

[0033] The DC voltage source may include a (for example three-phase) AC voltage source and a rectifier arranged between the (for example three-phase) AC voltage source and the input side of the adaptive converter.

[0034] The superimposed AC voltage may include, for example, a triangular voltage (also called a triangle voltage), a sinusoidal voltage (also called a sine-shaped voltage), a sawtooth voltage (also called a sawtooth-shaped voltage) and / or a rectangular voltage (also called a rectangular wave voltage). Alternatively or additionally, the superimposed AC voltage may include a trapezoidal voltage (also called a trapezoidal wave voltage).

[0035] The superimposed AC voltage, for example a triangular voltage and / or a sinusoidal voltage, can include a continuous profile. A continuous profile of the superimposed AC voltage can enable and / or improve a rapid response of the switching cells of the LLC converter.

[0036] The device may also include two resistors, which are connected in series to form a voltage divider. The voltage divider may be connected between two poles on the output side of the adaptive converter and / or between two poles on the input side of the LLC converter. The control unit may be configured to adjust the output DC voltage of the adaptive converter as a function of the voltage tapped at a node between the first resistor and the second resistor of the voltage divider.

[0037] The voltage tapped between the first resistor and the second resistor of the voltage divider may include an actual voltage (also referred to as an actual value of the voltage).

[0038] Furthermore, the device may include a signal generator that couples a control signal of the superimposed AC voltage into the tapped voltage. The coupling may optionally be performed via a third resistor that is conductively connected to a node between the first resistor and the second resistor of the voltage divider via a first terminal. The third resistor may be conductively connected to the signal generator at a second terminal.

[0039] The superimposed AC voltage can be coupled to the control unit of the adaptive converter via a voltage divider on the input side of the LLC converter for voltage actual value detection.

[0040] Alternatively or additionally, an analog coupling-in (signal coupling-in) of a control signal of a superimposed AC voltage can be realized by means of a third resistor.

[0041] Furthermore, the signal generator can be electrically conductively connected to one of the two poles on the output side of the adaptive converter and / or to one of the two poles on the input side of the LLC converter. Alternatively or additionally, the signal generator can be arranged outside the adaptive converter.

[0042] Alternatively or additionally, the control signal of the superimposed AC voltage can be added to the voltage tapped off via the voltage divider.

[0043] The addition of the voltages on the input side of the control unit can include analog and / or digital coupling-in of control signals (signal coupling-in for short).

[0044] The control unit can be configured to adjust the output DC voltage of the adapter converter according to the actual voltage. The signal generator can couple the control signal of the superimposed AC voltage into the actual voltage. Optionally, the control signal can be added to the actual value in the control unit.

[0045] Alternatively or additionally, the control unit can be configured to adjust the output DC voltage of the adapter converter according to the rated voltage. The signal generator can couple the control signal of the superimposed AC voltage into the rated voltage. Optionally, the control signal can be added to a constant rated value in the control unit.

[0046] The device can include a signal generator coupled to a setpoint voltage and / or a signal generator coupled to an actual voltage.

[0047] The addition of the superimposed AC voltage to the constant desired value in the control unit can include analog and / or digital coupling in of control signals (signal coupling in for short).

[0048] The superposition of the output voltage of the adaptive converter with the AC voltage can include an analog signal coupling-in and / or a digital signal coupling-in in the control unit.

[0049] The voltage frequency on the input side of the adapter converter can include zero Hertz (Hz) of the DC voltage source. Alternatively or additionally, the frequency of the voltage on the input side of the adapter converter (before its rectification) for an input-side (e.g. three-phase) AC voltage source with a connected rectifier can be between 50 Hz and 60 Hz. Furthermore, alternatively or additionally, the frequency of the voltage on the input side of the adapter converter for the (e.g. aircraft) electrical network (before its rectification) can be between 100 Hz and 1000 Hz, in particular 400 Hz.

[0050] The frequency of the superimposed AC voltage can be between 0.5 Hz and 2 Hz, for example in the case of an AC voltage source with a connected rectifier on the input side of the adaptive converter and / or in the adaptive converter. The frequency of the superimposed AC voltage can be, in particular, 1 Hz.

[0051] Alternatively or additionally, the frequency of the superimposed AC voltage can be (for example slightly or slightly) greater than 2 Hz, for example in the case of a DC voltage source on the input side of an adaptive converter.

[0052] The input-side (e.g. three-phase) AC voltage source may, for example, include an AC voltage amplitude of 400 volts (V) to 500 V. Alternatively or additionally, the input-side DC voltage of the adaptive converter may, for example, include a DC voltage between 12 V and 800 V. For example, the AC voltage of the input-side (e.g. three-phase) AC voltage source may be rectified before being input to the adaptive converter.

[0053] The output DC voltage of the adaptive converter may be at least an integer multiple of the amplitude of the superimposed AC voltage, for example at least three times to at least 40 times.

[0054] Alternatively or additionally, the output DC voltage of the adaptive converter can be 800 V. Furthermore, alternatively or additionally, the amplitude of the superimposed AC voltage can be between 10V and 20V.

[0055] According to a second aspect, a method for providing a stable DC voltage supply is provided. The method includes the step of adapting a DC voltage from a DC voltage source or adapting an AC voltage from an AC voltage source by means of an adapting converter. In addition, the method includes the step of superimposing the output DC voltage of the adapting converter with an AC voltage, wherein the amplitude of the superimposed AC voltage is less than the output DC voltage of the adapting converter. The method also includes the step of converting (also referred to as transforming) the output DC voltage of the adapting converter superimposed with the AC voltage by means of an LLC converter. The LLC converter is configured to provide a stable DC voltage supply on the output side, wherein the DC voltage of the stable DC voltage supply on the output side is a function of the switching frequency of the LLC converter. According to the method, the frequency of the superimposed AC voltage is less than the switching frequency of the LLC converter. The method also includes the step of providing a stable DC voltage on the output side of the LLC converter.

[0056] The method may include the step of rectifying the (eg three-phase) AC voltage of the AC voltage source by means of a rectifier. Furthermore, the method may include the step of providing the rectified voltage as the DC voltage of the DC voltage source at the input side of the adaptive converter.

[0057] The method of the second aspect may also be referred to as a method for frequency jittering of an input voltage with low ripple in an LLC converter (English: LLC converter), or simply referred to as an LLC jittering method.

[0058] The method of the second aspect can be implemented with the aid of the apparatus of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The present invention is described in detail below according to preferred embodiments with reference to the accompanying drawings.

[0060] Figure 1 An illustrative embodiment of an LLC converter is shown;

[0061] Figure 2A and 2B A schematic first embodiment of the device according to the invention for a stable DC voltage supply is shown, which comprises an LLC converter, for example Figure 1 The LLC converter has Figure 2A The DC voltage source shown in Figure 2B The AC voltage source shown in;

[0062] Figure 3 A schematic diagram showing a second embodiment of the device for stabilizing a DC voltage supply according to the present invention comprises an LLC converter, for example Figure 1 LLC converter;

[0063] Figure 4A schematic diagram showing a third embodiment of the device for stabilizing a DC voltage supply according to the present invention comprises an LLC converter, e.g. Figure 1 LLC converter;

[0064] Figure 5 shows a schematic frequency spectrum variation curve of the output voltage of a conventional LLC converter as a function of the switching frequency; and

[0065] Figure 6 The device for stable DC voltage supply according to the present invention is shown, for example according to Figure 2A , 2B , 3 or 4, the output voltage of the device is the same as that of the LLC converter, e.g. Figure 1 Schematic spectrum variation curve of the LLC converter as a function of the switching frequency. DETAILED DESCRIPTION

[0066] Figure 1 1 shows an exemplary embodiment of an LLC converter 100. The LLC converter 100 includes a first inductor ( Figure 1 "L" or "Ls") 104-1, a second inductor ("L") 104-2 and a capacitor ( Figure 1 "C" or "Cr" in)106-1.

[0067] Figure 1 The exemplary LLC converter 100 further includes a third inductor 104-3 inductively coupled to the second inductor 104-2. The second inductor 104-2 and the third inductor 104-3 preferably form a transformer (T1) 102.

[0068] On the input side of the exemplary LLC converter 100, there is a smoothing capacitor (C1) 106-2 and two semiconductor switches (S1, S2) 108. The semiconductor switches (S1, S2) 108 can be switched by means of a schematically shown switching unit 112 according to the switching frequency of the LLC converter 100. For example, the first semiconductor switch (S1) 108 can be switched to be conductive, while the second semiconductor switch (S2) 108 is switched to be non-conductive, or vice versa.

[0069] The output side of the LLC converter 100 includes a rectifier, such as a plurality of diodes 110 (D1, D2, D3, D4) for rectifying the output voltage of the LLC converter 100. In addition, the output side of the exemplary LLC converter 100 includes a smoothing capacitor 106-3 (C2).

[0070] Figure 2A and 2B, 3 and 4 respectively show an embodiment of the device for stable DC voltage supply according to the present invention. The device of the first embodiment is generally represented by the reference numeral 200-1. The device of the second embodiment is generally represented by the reference numeral 200-2. The device of the third embodiment is generally represented by the reference numeral 200-3.

[0071] exist Figure 2A , 2B , 3 and 4, the same or equivalent components are represented by the same figure marks respectively.

[0072] exist Figure 2A , 3 4 show, by way of example, a three-phase AC voltage source 202 and a downstream rectifier 204 , via which the DC voltage is fed to an adaptation converter 206 , for a DC voltage source.

[0073] Figure 2B The exemplary embodiment of FIG. 2 shows a three-phase AC voltage source 202 which is directly connected to the input side of an adaptation converter 206 .

[0074] Devices 200-1; 200-2; 200-3 are respectively included in Figure 2A , 2B , 3 and 4 and denoted by reference numeral 100 . Figure 2A , 2B , 3 and 4 of the LLC converter 100 may correspond to Figure 1 LLC converter 100. Alternatively or additionally, Figure 2A , 2B The LLC converter 100 in , 3 and 4 may also include other embodiments of the LLC converter (not shown).

[0075] The devices 200-1, 200-2, and 200-3 also each include an adaptor 206 having a control unit 208. The control unit 208 is designed to receive both a setpoint value 210 of the output DC voltage and an actual value 212 of the output DC voltage of the adaptor 206. The actual value 212 of the output DC voltage is Figure 2A , 2B In the embodiments 200-1; 200-2; 200-3 of the embodiments 3 and 4, respectively, it is determined between the first resistor (R1) 214 and the second resistor (R2) 216 of the voltage bridge.

[0076] In various embodiments, the apparatus 200-1; 200-2; 200-3 includes a signal generator 219 for the superimposed AC voltage 218. The superimposed AC voltage 218 is low frequency. Here, low frequency means low enough to make the switching unit (e.g. Figure 1 The frequency at which the switching unit 112 in can respond to voltage changes.

[0077] Furthermore, the amplitude of the superimposed AC voltage 218 is smaller, for example, multiple times smaller, than the amplitude of the output DC voltage of the adaptive converter 206. For example, the amplitude of the superimposed AC voltage can be at most 20V, in particular between 10V and 20V.

[0078] The LLC converter 100 can have a response time of, for example, 0.5 ms to 1 ms, within which it can adjust to disturbances on the output voltage (for example by means of the switching unit 112). However, for large devices (for example the device 200-1; 200-2; 200-3), higher values ​​of the response time of the LLC converter 100, up to about 5 ms, are also possible. Another characteristic value that can be described in principle in the same way as the response time of the LLC converter is the bandwidth of the switching unit (also called regulator) 112 in the LLC converter 100. It can also be said that the switching unit (also called regulator) 112 of the LLC converter 100 has a bandwidth of about 5 kHz to 8 kHz. However, for larger devices (for example the device 200-1; 200-2; 200-3), values ​​of only 1 kHz are also conceivable.

[0079] An exemplary switching frequency of the LLC converter 100 may be between 80 kHz and 120 kHz. Alternatively or additionally, in (particularly larger) devices (e.g., devices 200-1; 200-2; 200-3), the switching frequency may tend to be lower (e.g., to only 30 kHz to 40 kHz). Furthermore, alternatively or additionally, in (particularly smaller) devices (e.g., devices 200-1; 200-2; 200-3), the switching frequency may also be higher (e.g., in the range of 150 kHz).

[0080] The switching frequency of the LLC converter 100 and the response time of the LLC converter 100 do not have to be directly and / or functionally related to one another. Alternatively or additionally, the switching frequency of the LLC converter 100 is significantly higher than the bandwidth of the switching unit (also referred to as the regulator) 112 in an embodiment in order to prevent the switching frequency from interferingly coupling into the circuit (also referred to as the regulating device).

[0081] Alternatively or additionally, the bandwidth limitation of the switching unit (also referred to as the regulator) 112 may be a parameter of the components used in the device (e.g., the device 200-1; 200-2; 200-3), such as a parameter of the inductance (especially of the transformer) and / or the output capacitance. Furthermore, alternatively or additionally (e.g., in most cases), the switching frequency of the LLC converter 100 is not a limiting parameter of the response time of the switching unit (also referred to as the regulator) 112.

[0082] According to the invention, the superimposed (also modulated) AC voltage 218 on the input voltage of the LLC converter 100 changes more slowly (in particular by a large or multiple, for example at least an integer multiple) than the response time of the switching unit (also called regulator) 112. Alternatively or additionally, according to the invention, the frequency of the superimposed AC voltage 218 is (in particular significantly, for example at least an integer multiple) smaller than the bandwidth of the switching unit (also called regulator) 112 in order to prevent the superimposed AC voltage 218 from also being observable (i.e. visible) on the output voltage of the LLC converter 100.

[0083] The frequency of the AC voltage 218 superimposed on the input voltage of the LLC converter 100 may be selected to be low, for example in the range of 1 Hz, for the following reasons:

[0084] 1) The AC voltage 218 can also provide a modulation of the input current of the adaptive converter 206. Conventionally, when a 3-phase AC voltage (also referred to as a network voltage) is provided to the input current of the adaptive converter 206, the AC voltage (also referred to as a network voltage) has a frequency of 50 Hz. In one embodiment, the control unit (also referred to as a regulator) 208 of the adaptive converter 206 can be designed to be very slow (e.g. corresponding to a bandwidth of about 10 Hz) so as to prevent the control unit (also referred to as a regulator) 208 from causing asymmetry in the network current (e.g. at the output side of the adaptive converter 206) (e.g., the positive half-wave of the network voltage is greater than the negative half-wave of the network voltage). According to this embodiment, the frequency of the (also referred to as modulated) AC voltage 218 superimposed on the output voltage of the adaptive converter 206 is (especially) significantly smaller than the bandwidth of the control unit 208 of the adaptive converter 206 (and / or the switching unit 112 of the LLC converter 100) so as not to interfere with and / or over-demand the control unit (also referred to as a regulator) 208 (and / or the switching unit 112).

[0085] 2) Experiments have shown that modulation frequencies between 1 Hz and 2 Hz (and / or the frequency of the superimposed AC voltage 218) can produce a good form of a flattened peak in the spectrum. Depending on the modulation frequency (and / or the frequency of the superimposed AC voltage 218), the form can also look different, in particular deviating from the flattened peak (e.g. including two large "horn-shaped peaks" to the right and left of the platform). According to some (or all) embodiments, the modulation frequency (and / or the frequency of the superimposed AC voltage 218) therefore has an influence on the shape of the peak rather than its width.

[0086] The width of the peak in the spectrum of the LLC converter 100 may be related to the amplitude of the superimposed (also called modulated) AC voltage 218. The higher the amplitude, the more the LLC converter 100 according to an embodiment of the present invention must adjust its frequency to keep the output voltage stable. The maximum and minimum switching frequencies of the LLC converter 100 may determine the width of the peak.

[0087] exist Figure 2A and 2B In each of the embodiments of the devices 200-1; 200-2; 200-3 in , 3 or 4, a connection 220 for a stable DC voltage supply is also shown on the output side of the LLC converter 100, which DC voltage supply can be electrically conductively connected to a load (not shown), for example.

[0088] exist Figure 2A and 2B In the embodiment of the device 200-1 in FIG. 1 , the AC voltage 218 is coupled to the voltage divider (R1; R2) 214; 216 via a third resistor (Rk) 222. Figure 2A and 2B In the exemplary embodiment, the coupling is performed by an actual value detection 212 of the output DC voltage of the adaptation converter 206 and / or the input DC voltage (Vzk) of the LLC converter 100 .

[0089] The input DC voltage (Vzk) of the LLC converter 100 may correspond to the output DC voltage of the adaptation converter 206 .

[0090] exist Figure 2A and 2B In the embodiment of the present invention, the signal coupling of the AC voltage 218 is performed in an analog manner (referred to as analog signal coupling for short).

[0091] exist Figure 2A In the exemplary embodiment of FIG. 2 , the adaptive converter 206 is fed by a three-phase AC voltage 202 , which is converted into a DC voltage by means of a rectifier 204 before being input to the adaptive converter 206 .

[0092] exist Figure 2BIn the exemplary embodiment of FIG. 2 , the adaptation converter 206 is fed (in particular directly) by the three-phase AC voltage 202 .

[0093] exist Figure 2B In an embodiment of the invention, the adaptation converter 206 can, for example, include a bridgeless rectifier, in particular a Vienna rectifier, and is (for example directly) connected to the AC voltage 202 and provides an output DC voltage, in particular an adjustable one.

[0094] exist Figure 3 and 4 The following embodiments of the invention each show a circuit with a rectifier 204 between an AC voltage source 202 and an adaptation converter 206. Figure 2B In addition to the embodiments of the present invention, further embodiments (not shown) may include integrating the rectifier 204 into the adaptation converter 206.

[0095] exist Figure 3 In the embodiment of the device 200-2 in FIG. 1 , the superimposed AC voltage 218 is coupled in between the voltage divider (R1; R2) 214; 216 and the control unit 208. Alternatively or additionally, the superimposed AC voltage 218 is coupled in between Figure 3 In the embodiment of the present invention, it can be performed in the control unit 208. Figure 3 In FIG. 2 , the coupling-in of the superimposed AC voltage 218 is schematically shown as being added (“+”) to the actual value 212. The superimposed AC voltage 218 is Figure 3 The signal coupling into the output DC voltage of the adaptation converter 206 and / or the input DC voltage (Vzk) of the LLC converter 100 can be performed in an analog and / or digital manner.

[0096] exist Figure 4 In the embodiment of the device 200-3 in FIG. 1 , the superimposed AC voltage 218 is coupled in via a setpoint value detection 210 of a control unit 208 of the adapter converter 206. Figure 4 As schematically shown in FIG. 2 , a superimposed AC voltage 218 can be added (“+”) to the particularly constant rated voltage 210. The superimposed AC voltage 218 Figure 4 The signal coupling in the embodiments of can be performed analogously and / or digitally. Figure 4 In the embodiment of FIG. 2 , the signal coupling may be performed in the control unit 208 .

[0097] exist Figure 2A , 2BIn each of the embodiments of the devices 200-1; 200-2; 200-3 in , 3 or 4, a triangular voltage is shown as an example as the AC voltage 218. However, other embodiments of the AC voltage 218 can also be realized, in particular as a sinusoidal voltage, a sawtooth voltage and / or a rectangular voltage (also called a rectangular wave voltage). The shape of the frequency spectrum on the output side of the LLC converter depends on the respective embodiment of the AC voltage 218.

[0098] The triangular voltages shown as well as sinusoidal voltages (and / or trapezoidal voltages, for example) have the advantage of a continuous voltage curve.

[0099] When the input voltage of the LLC converter 100 changes in a stepwise manner, if the output voltage is to remain stable, the LLC converter 100 must also change its switching frequency in a stepwise manner. However, due to the response time of the switching unit (also referred to as the regulator) 112, the LLC converter 100 is generally not able to adjust its frequency arbitrarily fast. Therefore, interferences on the output voltage can be seen, especially in the case of high frequencies of the superimposed AC voltage 218 and / or in the case of discontinuous voltage variation curves of the superimposed AC voltage 218. It is therefore advantageous that the AC voltage 218 on the input voltage of the LLC converter 100 has a continuous variation curve. Alternatively or additionally, the switching unit (also referred to as the regulator) 112 of the LLC converter 100 can well adjust continuous voltage variations.

[0100] Alternatively or additionally, a superimposed AC voltage (also called modulation signal) 218 ​​with discontinuities (eg rectangular, sawtooth) may be advantageous. The shape of the superimposed AC voltage (also called modulation signal) influences, for example, the shape of the peaks in the frequency spectrum.

[0101] Furthermore, as an alternative or in addition, small disturbances in the output voltage of LLC converter 100 may also be tolerated, depending on the application, so that the superimposed AC voltage (also referred to as modulation signal) 218 ​​with the step is not too much of a problem.

[0102] In principle, any desired form of superimposed AC voltage 218 with a suitable (and / or determined) amplitude and frequency can be used. Figure 2A , 2B In each of the embodiments of the apparatus 200-1; 200-2; 200-3 in , 3 or 4, the adaptive converter 206 is exemplarily configured as a boost converter. However, other embodiments of the adaptive converter 206, in particular as a buck converter and / or a boost-buck converter, are also possible.

[0103] Figure 5 The conventional output spectrum of an LLC converter is shown as an example. Figure 1LLC converter 100. Figure 5 The spectrum in is also called the example spectrum without LLC jitter.

[0104] exist Figure 5 At reference numeral 502 in FIG. 1 , the abscissa is plotted as the corresponding frequency in Hertz (Hz). The logarithmic unit of the voltage measure in decibel-microvolt (dBμV) is plotted on the ordinate at reference numeral 504. The quasi-peak limit value (also called quasi-peak limit or quasi-peak characteristic value) is plotted at reference numeral 506, and the average limit value (also called average limit or average characteristic value) is depicted at reference numeral 508. The quasi-peak limit value and / or the average limit value may be determined by an LLC converter (e.g. Figure 1 The EMV of the LLC converter 100 in the embodiment is predetermined.

[0105] At reference numeral 510, a spectrum of quasi-peak measurements (also referred to as Quasi-Peak measurements) of a conventional LLC converter having an input voltage with low voltage ripple is depicted. Figure 5 As can be seen, for example, in the frequency range at 300 kHz and 500 kHz, a conventional quasi-peak spectrum includes narrowband peaks that may exceed one of the limit values, for example the average limit value at reference numeral 508 .

[0106] At reference numeral 512, a spectrum of average measurements (also referred to as Average measurements) of a conventional LLC converter with an input voltage having low voltage ripple is plotted. In this conventional spectrum, narrowband spikes are also evident.

[0107] Figure 6 Shows Figure 2A , 2B , 3 or 4. The output spectrum is provided at the tap denoted by reference numeral 220, for example. Figure 6 The spectrum in can also be referred to as an example spectrum with LLC jitter.

[0108] The same parameters (e.g. coordinate axes, characteristic values ​​and / or limit values) are Figure 5 and Figure 6 The same reference numerals are used in the drawings.

[0109] exist Figure 6 At reference numeral 610 in FIG. 1 is the spectrum of the quasi-peak measured values ​​(also called quasi-peak measured values) at the output end (e.g., the connection 220 for the stable DC voltage supply) of the LLC converter 100 of the device 200 - 1 ; 200 - 2 ; 200 - 3 according to the present invention. Figure 5 Compared with the conventional spectrum, Figure 6 The spectrum of φ includes broadened and flattened peaks, as can be seen, for example, in the frequency range at about 300 kHz and about 500 kHz.

[0110] At reference numeral 612 is the spectrum of the average measured value (also referred to as Average measured value) at the output of the LLC converter 100 (eg, the connection 220 of the stable DC voltage supply) of the device 200-1; 200-2; 200-3 according to the present invention. Figure 5 compared to, Figure 6 The broadening and flattening of the peaks can also be seen in this spectrum.

[0111] For example, according to Figure 5 and Figure 6 It can be seen from the comparison that since the energy is distributed over a larger frequency range, a stronger change in the switching frequency of the LLC converter 100 than the conventional one will produce a lower quasi-peak value (also called quasi-peak value) and average value (also called Average value) in the spectrum.

[0112] Alternatively or additionally, the device according to the invention (e.g. Figure 3 , 4 Or the average value (also called Average value) of the device 200-1; 200-2; 200-3 in 5 can be significantly lower than the quasi-peak value (also called quasi-peak value).

[0113] Therefore, when using the device according to the present invention (e.g. Figure 2A and 2B , 3 or 4 of the device 200-1; 200-2; 200-3) and / or the superimposed AC voltage 281 is fed into the input DC voltage of the LLC converter 100, less expenditure is required than conventionally for EMC measures, in particular EMC measures of the LLC converter 100.

[0114] Through LLC converter, for example Figure 1 The input DC voltage and the output DC voltage of the LLC converter 100 determine its switching frequency. If the input DC voltage of the LLC converter 100 is now changed, then according to the invention its switching frequency must also be changed in order to produce an equally high output DC voltage (e.g. at the connection 220 of the stable DC voltage supply). If the input DC voltage according to the invention is changed only slowly, the switching unit 112 (also called the regulating device) of the LLC converter 100 can readjust the output DC voltage quickly enough so that disturbances (especially in terms of the frequency and amplitude of the input DC voltage) do not penetrate into the output DC voltage.

[0115] According to the invention, the technical solution is that an adapting converter 206 is present between the input DC voltage and the LLC converter 100 , which supplies the LLC converter 100 with its output DC voltage.

[0116] Furthermore, according to the invention, the technical solution is to change (i.e. manipulate) the output DC voltage of the adaptive converter 206 in such a way that the AC voltage 218 is superimposed on it in a targeted manner. Due to the change in the output DC voltage of the adaptive converter 206, the switching frequency of the LLC converter 100 must also be changed (especially in the case of a constant output DC voltage of the LLC converter 100, for example at the connection 220 of the stable DC voltage supply).

[0117] According to one embodiment, the device for a stable DC voltage supply according to the invention is fed by a three-phase (also called 3-phase) AC voltage source (also called network voltage) 202, which is then rectified 204. A boost converter (also called boost converter, English: Boost-Converter) is then connected as an adaptation converter 206. An AC voltage (e.g., a triangular voltage or sawtooth voltage) 218 ​​is superimposed on the actual value of the output DC voltage of the boost converter 206, which causes the output DC voltage of the boost converter 206 to fluctuate accordingly (e.g., at an average value of 805 volts, at a frequency of 1.2 Hz, with an amplitude of ±7 V). The fluctuating input DC voltage causes jitter (also called frequency jitter) of the time clock of the LLC converter 100.

[0118] The device of this embodiment or any embodiment can provide an adjustable output DC voltage of 22.5V to 29.5V, in particular an adjustable output DC voltage of 24V (for example, in Figure 2A , 2B , 3 or 4). The output current can be in the range of 2.5 amperes (A) to 40 A. In particular, the output current can include 2.5 A, 5 A, 10 A, 20 A and / or 40 A.

[0119] According to further exemplary embodiments, output DC voltage values ​​of 12 V, 48 V, 120 V or 250 V are possible. Alternatively or additionally, the output current can be in the range of several hundred amperes, for example 200 A or 1000 A.

[0120] The present invention is not limited to the voltage values ​​or current values ​​(collectively referred to as characteristic values) of the above-described embodiments, but is also applicable to other combinations of characteristic values.

[0121] According to another embodiment, the adaptation converter 206 includes a step-down converter (also called a buck converter, English: Buck-Converter), a step-up converter (English: Buck-Boost-Converter), a flyback converter (English: Flyback Converter), a SEPIC converter, a flow converter and / or a bridge converter.

[0122] In each embodiment, the LLC converter 100 may include its own regulating circuit, for example integrated in the switching unit 112 (or including the switching unit). Alternatively or additionally, the superimposed AC voltage 218 may influence the control unit 208 of the adaptive converter 206 .

[0123] Furthermore, alternatively or additionally, the regulating circuit of LLC converter 100 is not intervened directly, but only indirectly, for example by changing the amplitude and frequency of the input DC voltage at the input of LLC converter 100 (in particular by superimposing the output DC voltage of adapter converter 206 with AC voltage 218).

[0124] Due to the change of the input DC voltage, the LLC converter 100 according to the embodiment of the present invention must change its switching frequency in order to make the output DC voltage (for example, Figure 2A , 2B , 3 or 4) is kept stable. This is done by the (eg already existing) switching unit 112 (ie the control circuit) of the LLC converter 100.

[0125] Therefore, according to the present invention, a change in the switching frequency of the LLC converter 100 can be forced indirectly by adapting the converter 206 without having to directly intervene in the switching unit 112 (ie, the regulating circuit) of the LLC converter 100 .

[0126] According to one embodiment, the device 200 - 1 ; 200 - 2 ; 200 - 3 according to the invention is fed by a DC voltage source, ie an input DC voltage with a frequency of 0 Hz.

[0127] According to a further exemplary embodiment, the device 200 - 1 ; 200 - 2 ; 200 - 3 according to the invention is fed by a (for example three-phase) AC voltage 202 , which has a frequency of 50 Hz to 60 Hz and is subsequently rectified 204 .

[0128] According to a further exemplary embodiment, the device 200 - 1 ; 200 - 2 ; 200 - 3 according to the invention is fed by an AC voltage 202 (for example, in particular from the electrical network of an aircraft) having a frequency of 400 Hz and subsequently rectified 204 .

[0129] According to a further exemplary embodiment, frequencies of more than 400 Hz of the AC voltage source 202 with subsequent rectification 204 are possible.

[0130] Alternatively or additionally, the higher the frequency of the voltage source 202 (eg with subsequent rectification 204 ), from which the adapted converter 206 is fed, the smaller the voltage ripple can be.

[0131] According to one embodiment, the frequency of the superimposed AC voltage 218, for example the frequency of the triangular voltage or the sawtooth voltage, can be between 0.5 Hz and 2 Hz. Alternatively or additionally, other frequencies of the superimposed AC voltage 218 are also possible, which correspond to a significantly slower change of the output DC voltage of the adaptation converter 206 and / or the input DC voltage of the LLC converter 100 than the reaction capacity of the switching unit (also referred to as LLC regulator) 112 of the LLC converter. Thus, the switching unit (also referred to as LLC regulator) 112 of the LLC converter 112 can keep the output DC voltage stable (for example, in Figure 2A , 2B , 3 or 4 in the joint 220).

[0132] According to further embodiments, the input DC voltage of the voltage source (also referred to as network) may be between 12 V and 800 V. Alternatively or additionally, an input AC voltage of the voltage source 202 (e.g. with subsequent rectification 204) between 100 V and 500 V, in particular between 400 V and 500 V, may be included. For example, Figure 2A , 2B The three-phase AC voltage source 202 in , 3 and 4 can provide a voltage between 400V and 500V to the rectifier 204 respectively.

[0133] According to another embodiment, in Figure 2A , 2B The input DC voltage Vzk of the LLC converter 100 in , 3 or 4 is 800 V, which is superimposed with a low-frequency AC voltage 218 having an amplitude of ±10 V to ±20 V and a frequency of 1 Hz.

[0134] The voltage values ​​and / or amplitudes mentioned in the exemplary embodiments, in particular (eg input and / or output) DC voltages, are exemplary. According to the invention, other voltage values ​​and / or amplitudes can be superimposed on the respectively appropriately selected AC voltage.

[0135] If the spectrum is completely unimportant, the input voltage of the LLC converter 100 will usually be kept as stable as possible. Now the AC voltage 218 is superimposed (i.e. modulated) for frequency jitter, which is intuitively contrary to the conventional requirements because it interferes with the switching unit (i.e. regulator) 112 of the LLC converter 100. Alternatively or additionally, the components may be subjected to a stronger load than in the conventional manner. For example, the input capacitor according to the present invention can be designed for a higher voltage than conventional (e.g., the amplitude of the DC voltage plus the AC voltage). These adverse effects can, in particular, limit the characteristic parameters of the superimposed AC voltage 218 in proportion to the characteristic parameters of the output voltage of the adaptation converter 206.

[0136] For example, in the case of an AC voltage 218 superimposed with 20V (i.e., ±20V peak voltage, abbreviated as ±20Vpk), a DC voltage of 800V (i.e., Vdc) can achieve a strong broadening of the peak in the spectrum while still allowing the device (e.g., device 200-1; 200-2; 200-3) to operate well and without overloading the components.

[0137] According to another embodiment, the AC voltage 218 superimposed with 10V (i.e., ±10V peak voltage, abbreviated as ±10Vpk) is suitable for strongly broadening the peaks in the spectrum for the DC voltage (i.e., Vdc) of 400V without overloading the components of the device (e.g., device 200-1; 200-2; 200-3).

[0138] According to another embodiment, a superimposed AC voltage 218 of 4V (i.e., ±4V peak voltage, abbreviated as ±4Vpk) is suitable for strongly broadening the peaks in the spectrum for a DC voltage (i.e., Vdc) of 160V without overloading the components of the device (e.g., device 200-1; 200-2; 200-3). For example, starting from the embodiment of a DC voltage of 800V superimposed with a 20V AC voltage 218, the ratio can be calculated as: (DC voltage value in V) / 800V×20V=(value of the allowed and / or suitable superimposed AC voltage in V).

[0139] Unless stated otherwise, all exemplary embodiments can be combined with one another.

[0140] Although the present invention has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be used instead. In addition, many modifications may be made to adapt specific situations or electrical power requirements to the teachings of the present invention. Therefore, the present invention is not limited to the disclosed embodiments, but includes all embodiments falling within the scope of the appended claims.

[0141] Description of Reference Numerals

[0142] LLC Converter 100

[0143] Transformer 102

[0144] Inductor 104-1; 104-2; 104-3

[0145] Capacitor 106-1; 106-2; 106-3

[0146] Semiconductor switch 108

[0147] Diode 110

[0148] Switch unit 112

[0149] Device 200-1; 200-2; 200-3 for stable DC voltage supply

[0150] Voltage source 202

[0151] Rectifier 204

[0152] Adaptor 206

[0153] Control unit 208

[0154] Voltage rating 210

[0155] The actual value of voltage 212

[0156] The first resistor 214 of the resistor bridge

[0157] The second resistor 216 of the resistor bridge

[0158] Superimposed AC voltage 218

[0159] Signal generator for superimposed AC voltage 219

[0160] Connector 220 for stable DC voltage supply

[0161] Resistor 222

[0162] Frequency (horizontal axis) 502

[0163] Voltage value (vertical axis) 504

[0164] Quasi-peak eigenvalue 506

[0165] Average eigenvalue 508

[0166] Quasi-peak measurement value 510 in the prior art

[0167] Average measurement value in the prior art 512

[0168] Quasi-peak measurement value 610 according to an embodiment of the present invention

[0169] Average measurement value 612 according to an embodiment of the present invention

Claims

1. A device (200-1; 200-2; 200-3) for supplying a stable DC voltage, comprising: an adapter (206) which is or can be connected in an electrically conductive manner to a DC voltage source (202, 204) or an AC voltage source (202) on the input side of the adapter (206); and an LLC converter (100) which is electrically conductively connected or connectable to the output side of the adaptation converter (206) on the input side, wherein the LLC converter (100) is designed to provide a stable DC voltage supply (220) on the output side, wherein the DC voltage of the stable DC voltage supply (220) on the output side is a function of the switching frequency of the LLC converter (100); The adaptor (206) comprises a control unit (208), wherein the control unit is configured to superimpose an output DC voltage of the adaptor (206) with an AC voltage (218); wherein the amplitude of the superimposed AC voltage (218) is smaller than the output DC voltage; and The frequency of the superimposed AC voltage (218) is less than the switching frequency of the LLC converter (100).

2. The device (200-1; 200-2; 200-3) according to claim 1, wherein: The DC voltage source (202, 204) comprises a three-phase AC voltage source (202) and a rectifier (204) arranged between the three-phase AC voltage source (204) and an input side of the adaptive converter (206).

3. The device (200-1; 200-2; 200-3) according to claim 1 or 2, wherein the adapted converter (206) comprises a boost converter, a buck converter and / or a boost-buck converter.

4. The device (200-1; 200-2; 200-3) according to any one of claims 1 to 3, wherein: The superimposed AC voltage (218) includes a triangular voltage, a sinusoidal voltage, a sawtooth voltage, and / or a rectangular voltage.

5. The device (200-1; 200-2; 200-3) according to any one of claims 1 to 4, further comprising two resistors (214; 216) connected in series to form a voltage divider, wherein the voltage divider is connected between two poles on the output side of the adaptive converter (206) and / or between two poles on the input side of the LLC converter (100), and wherein the control unit (208) of the adaptive converter (206) is constructed to adjust the output DC voltage of the adaptive converter (206) according to the voltage tapped at the node between the first resistor (214) and the second resistor (216) of the voltage divider.

6. The device (200-1; 200-2) according to claim 5, further comprising a signal generator (219) which couples a control signal of the superimposed alternating voltage (218) into the tapped voltage, The input is optionally coupled via a third resistor (222), which is electrically conductively connected via a first connection to a node between a first resistor (214) and a second resistor (216) of the voltage divider, wherein the third resistor (222) is electrically conductively connected to a signal generator (219) at a second connection.

7. The device (200-1) according to claim 6, wherein: The signal generator (219) is also electrically conductively connected to one of the two poles on the output side of the adaptation converter (206) and / or to one of the two poles on the input side of the LLC converter (100), and / or The signal generator (219) is arranged outside the adaptor (206).

8. The device (200-1; 200-2) according to claim 6 or 7, wherein a control signal of a superimposed alternating voltage (218) is added to the voltage tapped off via the voltage divider.

9. The device (200-1; 200-2) according to any one of claims 5 to 8, wherein: The control unit (208) is designed to adjust the output DC voltage of the adaptive converter (206) according to an actual voltage, wherein the signal generator (219) couples a control signal of a superimposed AC voltage (218) into the actual voltage. Optionally, the control signal is added to the actual value in the control unit (208).

10. The device (200-3) according to any one of claims 5 to 8, wherein: The control unit (208) is designed to adjust the output DC voltage of the adaptive converter (206) according to a setpoint voltage, wherein the signal generator (219) couples a control signal of a superimposed AC voltage (218) into the setpoint voltage. Optionally, the control signal is added to a constant setpoint value in the control unit (208).

11. The device (200-1; 200-2; 200-3) according to any one of claims 1 to 10, wherein: The superposition of the output voltage of the adaptive converter (206) with the superimposed AC voltage (218) comprises an analog signal coupling-in and / or a digital signal coupling-in in the control unit (208).

12. The device (200-1; 200-2; 200-3) according to any one of claims 1 to 11, wherein: The frequency of the superimposed AC voltage (218) is between 0.5 Hz and 2 Hz, Optionally, the frequency of the superimposed AC voltage (218) is 1 Hz.

13. The device (200-1; 200-2; 200-3) according to any one of claims 1 to 12, wherein: The output DC voltage of the adaptive converter is at least an integer multiple of the amplitude of the superimposed AC voltage (218); and / or Wherein, the output DC voltage of the adapter converter is between 400V and 800V; and / or The amplitude of the superimposed AC voltage (218) is between 10V and 20V.

14. A method for providing a stable DC voltage supply (220), comprising the following steps: Adapting a DC voltage from a DC voltage source (202, 204) or an AC voltage from an AC voltage source (202) by means of an adaptor (206); superimposing the output DC voltage of the adaptor converter (206) and the AC voltage (218); wherein the amplitude of the superimposed AC voltage (218) is smaller than the output DC voltage of the adaptive converter (206); An output DC voltage of the adaptation converter (206) superimposed on the AC voltage (218) is converted by means of an LLC converter (100), wherein the LLC converter (100) is designed to provide a stable DC voltage supply (220) on the output side, wherein the DC voltage of the stable DC voltage supply on the output side is a function of the switching frequency of the LLC converter (100); wherein the frequency of the superimposed AC voltage (218) is less than the switching frequency of the LLC converter (100); and A stable DC voltage is provided at the output side of the LLC converter (100).

15. The method according to claim 14, further comprising the steps of: rectifying the AC voltage of the AC voltage source (202) by means of a rectifier (204); and The rectified voltage is provided on the input side of the adaptation converter (206) as the DC voltage of the DC voltage source.

Images