DC voltage converter system and method for controlling multiple DC voltage converters

Abstract

This invention presents a DC-DC converter system, wherein said DC-DC converter system comprises: several DC-DC converters, each DC-DC converter comprising one input and one output, wherein the inputs of said several DC-DC converters are all connected in series or in parallel with each other, and the outputs of said several DC-DC converters are all connected in series or in parallel with each other;and a central control device configured to generate a unified control signal using one of the DC-DC converters as a control reference or using the unit formed by the multiple DC-DC converters as a control reference, in order to control the multiple DC-DC converters jointly based on the unified control signal, so that the total output voltage of the multiple DC-DC converters approaches the total setpoint voltage. Furthermore, this invention provides a method for controlling multiple DC-DC converters and a computer program product.

Description

AREA OF INVENTION

[0001] This invention relates to a DC-DC converter system, furthermore to a method for controlling several DC-DC converters and a computer program product. STATE OF THE ART

[0002] Due to the diverse power supply requirements of the various electronic devices in the vehicle, a combination of several DC / DC converters is sometimes used in the electrical system of vehicles.

[0003] Currently, each DC-DC converter is typically assigned an independent local controller. These local controllers are responsible for the independent management of each converter's operation. While this approach can meet the system's essential control requirements to a certain extent, it also has limitations. For example, a separate control scheme often needs to be designed for each circuit topology, and if the circuit topology changes, the control mode of each controller must be adjusted accordingly. This not only makes the design more complex and the control more difficult, but can also negatively impact overall efficiency and performance. Furthermore, if the number of converters in the system needs to be increased, an additional controller must be planned and implemented for each newly added converter, resulting in poor system scalability.

[0004] Consequently, the current state of the art still has shortcomings with regard to the control of multiple DC-DC converters. REVELATION OF THE INVENTION

[0005] The objective of this invention is to provide a DC-DC converter system, a method for controlling multiple DC-DC converters, and a computer program product to solve at least some of the problems existing according to the current state of the art.

[0006] According to a first aspect of this invention, a DC-DC converter system is provided, wherein said DC-DC converter system comprises the following: Several DC-DC converters, each DC-DC converter comprising one input and one output, wherein the inputs of said several DC-DC converters are all connected in series or in parallel with each other, and the outputs of said several DC-DC converters are all connected in series or in parallel with each other; and a central control device configured to generate a unified control signal using one of the DC-DC converters as a control reference or using the unit formed by the multiple DC-DC converters as a control reference, in order to control the said multiple DC-DC converters jointly based on the unified control signal, so that the total output voltage of the said multiple DC-DC converters approaches the total setpoint voltage.

[0007] This invention incorporates the following technical concept: By generating a uniform control signal based on a single DC-DC converter or the entire system as a control basis, and applying this uniform control signal to each DC-DC converter, the passive balancing capability of the system is fully utilized, thereby reducing the system's inherent instability. This effectively simplifies the control of a combination of multiple DC-DC converters. Thanks to this centralized control architecture, a uniform control scheme can be used for different circuit topologies, and the system can respond quickly to changes in the circuit topology and varying setpoint voltage requirements, which in turn ensures a more stable and reliable voltage output.Furthermore, this type of design also significantly reduces the complexity of system expansion, as newly added converters can be seamlessly integrated into the existing control system without the need to plan and arrange additional local controllers, thus increasing the system's flexibility.

[0008] According to a second aspect of this invention, a method for controlling multiple DC-DC converters is provided, wherein said method is carried out using said DC-DC converter system according to the first aspect of this invention, and said method comprises the following steps: generating a unified control signal using one of the DC-DC converters as a control reference or using the unit formed by the multiple DC-DC converters as a control reference; and jointly controlling said multiple DC-DC converters based on the unified control signal, such that the total output voltage of said multiple DC-DC converters approaches the total setpoint voltage.

[0009] According to the third aspect of the present invention, a computer program product is provided with program code units, wherein the program code units are configured to cause the computer, when the computer program product is executed on a computer or when stored on a computer-readable storage medium, to execute the method according to the second aspect of the present invention. DESCRIPTION OF THE FIGURES

[0010] The present invention is described in more detail below with reference to the figures, so that its principles, features, and advantages become even clearer. The figures include the following: Fig. Figure 1A shows a block diagram of the DC-DC converter system according to an exemplary embodiment of this invention; Fig. Figure 1B shows a block diagram of the DC-DC converter system according to another exemplary embodiment of this invention; Fig. Figure 1C shows a schematic representation of a DC / DC flyback converter with active clamp according to an exemplary embodiment of this invention; The Fig. 2A, Fig. 2B, Fig. 2C and Fig. Figures 2D show, in schematic representation, the ISOS, ISOP, IPOS and IPOP topologies of the multiple DC-DC converters; Fig. Figure 3 shows a block diagram of the central control device according to an exemplary embodiment of this invention; Fig. Figure 4 shows a block diagram of the voltage feedback control module of the central control device according to an exemplary embodiment of this invention; Fig. Figure 5 shows a block diagram of the feedforward control module of the central control device according to an exemplary embodiment of this invention; Fig. Figure 6 shows a block diagram of the current feedback control module of the central control device according to an exemplary embodiment of this invention; Fig. 7A and Fig. Figure 7B shows a block diagram of the voltage equalization module according to an exemplary embodiment of this invention; Fig. Figure 8 shows a block diagram of the current balancing module according to an exemplary embodiment of this invention; Fig. Figure 9 shows a block diagram of the temperature compensation module according to an exemplary embodiment of this invention; Fig. Figure 10 shows a flowchart of the method for controlling several DC-DC converters according to an exemplary embodiment of this invention; and Fig. Figure 11 shows in schematic form the process of passive compensation of the input voltages of the several DC voltage converters according to an exemplary embodiment of this invention. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0011] To better illustrate the technical problems, solutions, and advantageous effects to be solved by the present invention, the present invention will be explained in more detail below with reference to the figures and exemplary embodiments. It is understood that the specific embodiments described here serve only to illustrate the present invention and not to limit its scope of protection.

[0012] Fig. Figure 1A shows a block diagram of the DC voltage converter system 1 according to an exemplary embodiment of this invention.

[0013] See Fig. 1A, the DC-DC converter system 1, can, for example, be installed in a vehicle. "Vehicle" includes, for example, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), range-extended electric vehicles (EREVs), and battery electric vehicles (BEVs).

[0014] The DC / DC converter system 1 comprises several DC / DC converters 51, 52, 53, 5n. These converters are installed between the vehicle's high-voltage (HV) and low-voltage (LV) systems. The high-voltage (HV) system refers to the high-voltage section of a vehicle's electrical system, responsible for supplying power to the critical electric drive components and driver assistance systems. The voltage range of this system can be designed to be relatively broad (e.g., from 200 V to 1,000 V) to accommodate various operating conditions and load requirements. The low-voltage (LV) system in the vehicle's electrical system is responsible for supplying power to accessory devices. To meet the specific supply voltage requirements of these accessories, the low-voltage system can provide 12 V or 24 V auxiliary voltage as needed.For example, some conventional vehicle electronics may be designed to operate at 12V, whereas some commercial or special vehicles may require a 24V power supply.

[0015] Each DC-DC converter 51, 52, 53, 5n comprises one input and one output. The inputs of the multiple DC-DC converters can all be connected in series or in parallel, and the outputs of the multiple DC-DC converters can also all be connected in series or in parallel. Fig. Figure 1A further illustrates the input nodes 121, 122 on the high-voltage side and the output nodes 131, 132 on the low-voltage side of the unit formed by the several DC-DC converters, wherein the total input voltage (DC current) between the input nodes 121, 122 V INis and the total output voltage (DC) between the output nodes is 131, 132 V OUT Furthermore, the individual input voltage V is also present. IN_1 , V IN_2 , V IN_3 and V IN_4 of the individual DC-DC converters and also the individual output voltage V of each OUT_1 , V OUT_2 , V OUT_3 and V OUT_4 The individual DC-DC converters are shown. The inputs and outputs of the multiple DC-DC converters 51, 52, 53, 5n can have a fixed or a flexible connection type.

[0016] The DC-DC converter system 1 further comprises a central control device 20, wherein the central control device 20 can generate a uniform control signal using one of the DC-DC converters as a control reference or using the unit formed by the several DC-DC converters as a control reference, in order to jointly control the said several DC-DC converters 51, 52, 53, 5n based on the uniform control signal, so that the total output voltage V OUT the aforementioned several DC voltage converters 51, 52, 53, 5n approach the total target voltage V OUT_SET approaches.

[0017] In this context, "controlling several DC-DC converters together" is to be understood as causing all DC-DC converters 51, 52, 53, 5n to operate in a corresponding and correlated manner. In one embodiment, the central control device 20 can directly provide the uniform control signal to each DC-DC converter 51, 52, 53, 5n in order to control all DC-DC converters 51, 52, 53, 5n together.

[0018] In another embodiment, the central control device 20 can fine-tune the unified control signal before directly supplying it to each DC-DC converter. This fine-tuning can be performed based on the deviation between the operating states of the individual DC-DC converters 51, 52, 53, 5n, in order to compensate for the operating states of the multiple DC-DC converters 51, 52, 53, 5n. Subsequently, the modified unified control signal is supplied to at least one DC-DC converter 5n, and either the unmodified or the modified signal is supplied to the remaining DC-DC converters 51, 52, 53. The core of this control method consists of generating a common control signal, which is then simultaneously applied directly or indirectly to each DC-DC converter.Since all converters share the same basic rule logic, the coordination and coherence of the overall system is ensured.

[0019] In one embodiment, the central control device 20 can designate only one of the DC-DC converters 5n as the "control reference" and generate the uniform control signal with respect to this reference using a corresponding control loop. For this purpose, the central control device 20 can be connected to the sensors V1, A1, V2, A2 of one of the DC-DC converters 5n to receive the operating parameters (e.g., individual input voltage, individual input current, individual output voltage, and individual output current) of that DC-DC converter 5n. Based on these operating parameters, it then assesses the performance of the overall system and thus generates the uniform control signal. In another embodiment, the unit formed by the multiple DC-DC converters 51, 52, 53, 5n can also be considered as the control reference.For this purpose, the central control device 20 is connected to the sensors for measuring the total output / input voltage or the total output / input current of the several DC-DC converters (not shown in detail for simplicity). In this context, "control reference" can also be understood as a synonym for "controlled object," whereby the state (the operating parameters) of the object designated as the "control reference" is used as the basis for generating a control signal or setting operating parameters, and the control activities of all other objects are based on this.

[0020] In one embodiment, the uniform control signal is the duty cycle and / or frequency of the switching signal to be applied to the main switch of each DC-DC converter 51, 52, 53, 5n, and the central control device 20 is configured to dynamically adjust the duty cycle and / or frequency of said switching signal. Consequently, the central control device 20 can be connected to the main switch (for example, the control electrode of the power transistor) of each DC-DC converter 51, 52, 53, 5n so that the appropriate switching signal is applied to the main switch of each DC-DC converter 51, 52, 53, 5n.

[0021] Fig. Figure 1B shows a block diagram of the DC-DC converter system 1 according to another exemplary embodiment of this invention. For clarity, only two DC-DC converters 51 and 52 are shown in this embodiment.

[0022] As in Fig. As shown in Figure 1B, the DC-DC converter system 1 can further comprise a switching unit 30, wherein the switching unit 30 can change its switching state according to system requirements or operating conditions in order to switch the inputs of the multiple DC-DC converters 51, 52 so that they are connected in series or all in parallel to each other, and / or to switch the outputs of the multiple DC-DC converters 51, 52 so that they are connected in series or all in parallel to each other. As shown in Fig. As shown in Figure 1B as an example, the switching unit 30 can comprise a first switching component S21, a second switching component S22, and a third switching component S23. The first switching component S21 can be arranged between the second input node 152 of the first DC-DC converter 51 and the third input node 153 of the second DC-DC converter 52, the second switching component S22 can be arranged between the first input node 151 of the first DC-DC converter 51 and the third input node 153 of the second DC-DC converter 52, and the third switching component S23 can be arranged between the second input node 152 of the first DC-DC converter 51 and the fourth input node 154 of the second DC-DC converter 52.When the second switching component S22 and the third switching component S23 are switched on and the first switching component S21 is switched off, the inputs of the first DC-DC converter 51 and the second DC-DC converter 52 are connected in parallel. When the second switching component S22 and the third switching component S23 are switched off and the first switching component S21 is switched on, the inputs of the first DC-DC converter 51 and the second DC-DC converter 52 are connected in series. These switching components can be, for example, designed as a power MOSFET, bipolar transistor IGBT, power diode, and relay. It should be noted that in . Fig. Although Figure 1 B only shows the case where the switching unit 30 controls the connection between the inputs of the individual DC voltage converters 51, 52, it is also possible to place a corresponding switching unit on the output side of the DC voltage converters 51, 52 to control the connection between their outputs.

[0023] In one embodiment, the central control device 20 can be connected to the switching unit 30 to monitor the real-time switching state of the switching unit 30 and to determine the current topology of the multiple DC-DC converters 51, 52. This topology can then be taken into account when generating the unified control signal (for example, by considering the total setpoint voltage of each topology). For instance, the central control device 20 can receive the switching state of each switching component S21, S22, S23 from the switching unit 30 and, based on the combination of the switching states of these components S21, S22, S23, determine whether the inputs and outputs of all DC-DC converters 51, 52 are connected in parallel or in series.In another embodiment, if the connection method of the inputs and / or outputs of all DC voltage converters 51, 52 is fixed (i.e., no change can be made using a switching unit), the central control device 20 can generate the uniform control signal according to the standard topology.

[0024] For example, switching unit 30 switches when the total input voltage V INIf the input voltage is greater than 500 V, the inputs of the multiple DC-DC converters 51, 52 are connected in series. In this way, the high voltage can be distributed across the individual converters 51, 52, thus reducing the voltage stress on each converter. With a relatively low input voltage (up to 500 V), the switching unit 30 can connect the inputs of the multiple DC-DC converters 51, 52 in parallel. For example, if a voltage of 24 V is to be supplied to the low-voltage network, the switching unit 30 can connect the outputs of the multiple DC-DC converters 51, 52 in series so that their output voltages add up. Conversely, if the system is only to supply 12 V to the low-voltage network, the switching unit 30 can connect the outputs of these converters in parallel.

[0025] Fig. Figure 1C shows a schematic representation of a DC / DC flyback converter with active clamp according to an exemplary embodiment of this invention.

[0026] In one embodiment, the several DC-DC converters 51, 52, 53, 5n each have the same specifications, meaning that, within the permissible manufacturing tolerances, they have essentially identical structural parameters and stress ratios. In the embodiment described in Fig. In the embodiment shown in Figure 1C, each DC-DC converter is designed as a DC / DC flyback converter with active clamp, although for the sake of simplicity only one DC-DC converter 51 is shown here. The DC-DC converter 51 comprises a transformer 510, the transformer 510 having a primary winding 511 and a secondary winding 512. On the primary side, the DC-DC converter 51 comprises an input capacitor C1, a main switch S31, a clamp capacitor C2, and a clamp switch S32. On the secondary side, the DC-DC converter 51 comprises a synchronous rectifier switch S33, a snubber capacitor C3, a snubber switch S36, a safety switch S35, and an output capacitor C4.In this embodiment, all switches S31, S32, S33, S35, S36 are, for example, n-channel metal oxide semiconductor field-effect transistors (MOSFETs), but in practice other types of transistors or switches can also be used.

[0027] On the primary side, one end of the primary winding 511 is connected to the first input node 15 of the DC-DC converter 51, and the other end is connected to the drain of the main switch S31. The source of the main switch S31 is connected to the second input node 152, and the drain is connected to the drain of the clamp switch S32. The clamp capacitor C2 is connected in series with the clamp switch S32 between the first input node 151 and the drain of the main switch S31, and this series circuit is connected in parallel with the primary winding 511. The gate of the main switch S31 is connected to the central control device 20, allowing the uniform control signal generated by the central control device 20, or the modified uniform control signal, to be applied to the gate of the main switch S31.

[0028] On the secondary side, the safety switch S35 is connected by bridging between one end of the secondary winding 512 and the second output node 162. The other end of the secondary winding 512 is connected to the source of the synchronous rectifier switch S33, and the source of the synchronous rectifier switch S33 is connected to the first output node 161. The snubber capacitor C3 and the snubber switch S36 are connected in series to form a snubber circuit. This snubber circuit is connected in parallel to both ends of the secondary winding 512 to absorb voltage spikes caused by parasitic parameters of the circuit at the ends of S31 and S33. The output capacitor C4 is connected between the first output node 161 and one end of the secondary winding 512.

[0029] When this DC-DC converter 51 is in operation, the main switch S31 is cyclically switched on and off according to the control of the central control device 20. When the main switch S31 is switched on, current flows through the primary winding 511 and stores energy in the transformer 510. At this time, the synchronous rectifier switch S33 on the secondary side is switched off (or, if a diode is used as the synchronous rectifier switch, the diode does not conduct). When the main switch S31 is switched off, the current in the primary winding 511 drops rapidly, the synchronous rectifier switch S33 is switched on, and the secondary winding 512 generates a flyback voltage. While the main switch S31 is off, the clamp switch S32 is switched on, which causes the clamp capacitor C2 and the transformer to resonate, thus transferring energy to the secondary winding.In the next cycle, when the main switch S31 is switched on again, the clamp switch S32 is switched off and the energy stored in the clamp capacitor C2 is released back to the primary winding 511. This allows the main switch S31 to switch on at zero voltage, reducing switching losses. The signals from the main switch S31 and the clamp switch S32 are complementary, and a dead zone remains between them to prevent a short circuit caused by simultaneous switching.

[0030] The central control device 20 can output the unified control signal to the gate of the main switch S31 and output auxiliary drive signals to the gates of the other auxiliary switches S32, S33, S36. These auxiliary drive signals are adapted based on the unified control signal to precisely control each auxiliary switch S32, S33, S36, enabling synchronous or asynchronous operation with the main switch S31. As a functional safety switch, S35 is normally in the on (normally conducting) state.

[0031] Although in Fig. The DC / DC converter 51 is designed as a DC / DC flyback converter with active clamp, however, this solution is equally applicable to other types of DC / DC converters (such as buck converters, boost converters, inverse converters, phase-shifted full bridge converters, resonant half bridge converters and DAB converters (Dual Active Bridge) etc.).

[0032] The Fig. 2A, Fig. 2B, Fig. 2C and Fig. Figure 2D shows, in schematic representation, the ISOS, ISOP, IPOS and IPOP topologies of the multiple DC-DC converters.

[0033] In Fig. Figure 2A shows several DC-DC converters 51, 52, 53, 5n in an ISOS topology (inputs in series - outputs in series). The inputs of the individual DC-DC converters 51, 52, 53, 5n are all connected in series, and the outputs of the multiple DC-DC converters 51, 52, 53, 5n are also all connected in series. The individual input currents of all DC-DC converters 51, 52, 53, 5n are identical and also correspond to the total input current, and the individual output currents are identical and correspond to the total output current. The sum of the individual input voltages V IN_1 , V IN_2 , V IN_3 , V IN_4 The total input voltage V of all DC-DC converters 51, 52, 53, 5n INand the sum of the individual output voltages V OUT_1 , V OUT_2 , V OUT_3 , V OUT_4 corresponds to the total output voltage V OUT In this topology, the total target voltage V is OUT_SET On the output side, a first preset value is used (for example, 24 V); accordingly, the individual target voltages on the output side are V OUT_1SET , V OUT_2SET , V OUT_3SET , V OUT_4SET each DC-DC converter 51, 52, 53, 5n by the portions of the total target voltage V that are evenly distributed among all DC-DC converters 51, 52, 53, 5n OUT_SET (in the case of only two DC-DC converters, these are, for example, 12 V), so that consequently, by dividing the total target voltage V OUT_SET The individual target voltages V are determined by the number of DC-DC converters 51, 52, 53, 5n. OUT_1SET , V OUT_2SET , V OUT_3SET , V OUT_4SET Have it calculated.

[0034] In Fig. Figure 2B shows several DC-DC converters 51, 52, 53, 5n in an ISOP topology (inputs in series, outputs in parallel). The inputs of the individual DC-DC converters 51, 52, 53, 5n are all connected in series, and the outputs of the multiple DC-DC converters are all connected in parallel. The individual input currents of all DC-DC converters 51, 52, 53, 5n are identical. The sum of the individual input voltages V IN_1 , V IN_2 , V IN_3 , V IN_4 The total input voltage V of all DC-DC converters 51, 52, 53, 5n IN and the individual output voltages V OUT_1 , V OUT_2 , V OUT_3 , V OUT_4 are identical and correspond to the total output voltage V OUT In this topology, the total target voltage V is OUT_SETon the output side by a second preset value (for example 12 V), accordingly the individual setpoint voltages on the output side V OUT_1SET , V OUT_2SET , V OUT_3SET , V OUT_4SET The total set voltage V of all DC-DC converters is equal to the total set voltage. OUT_SET and consequently also the second preset value.

[0035] In Fig. Figure 2C shows several DC-DC converters 51, 52, 53, 5n in an IPOS topology (inputs in parallel, outputs in series). The inputs of the individual DC-DC converters 51, 52, 53, 5n are all connected in parallel, and the outputs of the multiple DC-DC converters are all connected in series. The sum of the individual input currents of all DC-DC converters 51, 52, 53, 5n yields the total input current, and the individual output currents are identical and correspond to the total output current. The individual input voltages V IN_1 , V IN_2 , V IN_3, V IN_4 All DC-DC converters 51, 52, 53, 5n are identical and correspond to the total input voltage V. IN and the sum of the individual output voltages V OUT_1 , V OUT_2 , V OUT_3 , V OUT_4 corresponds to the total output voltage V OUT In this topology, the total target voltage V is OUT_SET On the output side, a first preset value is used (for example, 24 V); accordingly, the individual target voltages on the output side are V OUT_1SET , V OUT_2SET , V OUT_3SET , V OUT_4SET each DC-DC converter 51, 52, 53, 5n by the portions of the total target voltage V that are evenly distributed among all DC-DC converters OUT_SET (that is, for example, 12 V).

[0036] In Fig. Figure 2D shows several DC-DC converters 51, 52, 53, 5n in an IPOP topology (inputs in parallel - outputs in parallel). The inputs of the individual DC-DC converters 51, 52, 53, 5n are all connected in parallel, and the outputs of the multiple DC-DC converters are all connected in parallel. The sum of the individual input currents of all DC-DC converters 51, 52, 53, 5n yields the total input current, and the sum of the individual output currents of all branch circuits yields the total output current. The individual input voltages V IN_1 , V IN_2 , V IN_3 , V IN_4 All DC-DC converters 51, 52, 53, 5n are identical and correspond to the total input voltage V. IN and the individual output voltages V OUT_1 , V OUT_2 , V OUT_3 , V OUT_4 are identical and correspond to the total output voltage V OUT In this topology, the total target voltage V is OUT_SETon the output side by a second preset value (for example 12 V), accordingly the individual setpoint voltages on the output side V OUT_1SET , V OUT_2SET , V OUT_3SET , V OUT_4SET All DC-DC converters 51, 52, 53, 5n equal to the total set voltage V OUT_SET and therefore also correspond to the second preset value.

[0037] In a comprehensive analysis of the Fig. From 2A to 2D, it can be seen that the individual DC-DC converters in each of the aforementioned topologies all have the same input / output characteristics, so that they react in the same way to the uniform control signal under identical conditions. Therefore, the individual DC-DC converters can, when the total output voltage V OUT the total target voltage V OUT_SETThe converters are approximated, passively adjust themselves, and reach a stable state. Consequently, a single DC-DC converter can be used as a control reference to generate a uniform control signal. This reduces the dependence on complex control algorithms, and the fundamental control of all converters is achieved via this uniform control signal.

[0038] In the aforementioned ISOS or IPOP typology, the inputs and outputs of all DC-DC converters are connected in the same way, so that the input / output characteristics of the entire system correspond to the input / output characteristics of a single DC-DC converter. Consequently, the state of a single DC-DC converter can be derived from the state of the entire system, making it possible to use either the unit formed by all DC-DC converters or one of the DC-DC converters as a control reference.

[0039] In the aforementioned IPOS or ISOP typology, the input / output characteristics of the overall system no longer directly correspond to those of the DC-DC converters, but rather change in a specific ratio to the input / output characteristics of the individual DC-DC converters. Consequently, in the IPOS or ISOP typology, one of the DC-DC converters can be selected as a control reference for generating the uniform control signal.

[0040] Fig. Figure 3 shows a block diagram of the central control device 20 according to an exemplary embodiment of this invention.

[0041] As in Fig. As shown in Figure 3, the central control device 20 comprises a main control unit 21 and a compensation unit 22. The main control unit 21 is responsible for collecting information on the state of a single DC-DC converter or the unit formed by all DC-DC converters and generating a uniform control signal using one of the DC-DC converters as a control reference or using the unit formed by the multiple DC-DC converters as a control reference. In one embodiment, the main control unit 21 can provide the uniform control signal directly to each DC-DC converter. In another embodiment, the main control unit 21 can be connected to the compensation unit 22 to provide the uniform control signal to the compensation unit 22.The compensation unit 22 can modify the uniform control signal based on the state deviation between at least two DC voltage converters and then apply the modified and / or the unmodified uniform control signal to the main switch of each DC voltage converter in order to stop the operation of each DC voltage converter.

[0042] The main control unit 21 can comprise a voltage feedback control module 211, a feedforward control module 212, and / or a current feedback control module 213. The voltage feedback control module 211 is responsible for monitoring the individual output voltage of one of the DC-DC converters, comparing it with the defined individual setpoint voltage, and generating a voltage deviation signal. Based on this voltage deviation signal, a voltage feedback control signal UCtrl is then generated, which is used to adjust the individual output voltage of this DC-DC converter to the individual setpoint voltage.Optionally, the voltage feedback control module 211 can also generate the voltage feedback control signal UCtrl based on the deviation between the total output voltage of the unit formed by all DC voltage converters and the total setpoint voltage, whereby this voltage feedback control signal UCtrl serves to adjust the total output voltage of the unit formed by the multiple DC voltage converters to the total setpoint voltage.

[0043] The feedforward control module 212 is used to generate a feedforward control signal (PreCtrl) based on the expected input-output relationship of the individual DC-DC converter or system unit. Using the feedforward control module 212, a rapid response to load changes or current fluctuations is possible, resulting in a significant improvement in the dynamic responsiveness and interference protection capabilities of the system.

[0044] The current feedback control module 213 is responsible for monitoring the individual input and / or output current of a single DC-DC converter and generating a current feedback control signal ICtrl by comparing it to the current limit. This current feedback control signal ICtrl ensures that the individual input and / or output current of one of the DC-DC converters does not exceed the limit current. This ensures that the operating current of each DC-DC converter remains within a safe range, thus preventing overload or short circuits.

[0045] The main control unit 21 can further comprise a combination module 214, wherein this combination module 214 combines the voltage feedback control signal UCtrl, the current feedback control signal ICtrl, and the feedforward control signal PreCtrl to generate the unified control signal Ctrl. For example, the combination module 214 can superimpose the signals from the various modules to generate the unified control signal Ctrl, which reflects the combined effect of all signals. Optionally, the combination module 214 can also subject each signal to weighting and dynamic adjustment of the weights in order to optimize the control effect. Optionally, the combination module 214 can also subject the signals of the different control modules to tuning in order to avoid control conflicts.Optionally, the combination module 214 can also function as a PWM generator to generate a main switch switching signal based on a uniform control signal Ctrl in the form of a duty cycle signal and / or switching frequency signal.

[0046] As in Fig. As shown in Figure 3, the central control device 20 can also include a compensation unit 22. Ideally, the structural / operating parameters of all DC-DC converters are identical, so that they respond in the same way to the uniform control signal. However, since manufacturing processes result in differences between the components, the load distribution is not uniform, or the environmental conditions change, imbalances may occur between the states of the individual converters, affecting the overall performance and reliability of the system. The compensation unit 22 can advantageously account for these differences between the operating states in order to compensate for imbalances between the operating states of the individual DC-DC converters.

[0047] The compensation unit 22 further comprises a voltage compensation module 221, a current compensation module 222, or a temperature compensation module 223, wherein each compensation module 221, 222, 223 can generate a compensation control signal Crr, and this compensation control signal Crr can be provided to modify the unified control signal Ctrl. Their respective structures and operating principles are explained in more detail in the following description. Furthermore, the compensation unit 22 can also include a modification module 224 to superimpose the unified control signal with the compensation control signals Crr output by the compensation modules 221, 222, 223 in order to modify it. It should be noted that the modification module 224 in Fig. Although shown independently of the individual compensation modules 221, 222, 223, the compensation unit 22 can also be part of the compensation modules 221, 222, 223 or can be integrated into them. Optionally, the compensation unit 22 of the central control device 20 can select the appropriate compensation strategy based on the topology between the multiple DC-DC converters to modify the uniform control signal Ctrl. This is particularly advantageous if the topology of the multiple DC-DC converters can be dynamically adjusted using the switching unit, as the compensation strategy can be adapted to several topologies, thus achieving balanced operation of the DC-DC converters in each topology through compensation measures.If the topology of the multiple DC-DC converters is, for example, an ISOS or ISOP topology, the voltage balancing module 221 is selected to modify the unified control signal. If the topology of the multiple DC-DC converters is, for example, an IPOS or IPOP topology, the current balancing module 222 is selected to modify the unified control signal.

[0048] In one embodiment, the unified control signal Ctrl is a duty cycle signal that indicates the proportion of time the main switch must be open within a specific period. Consequently, the duty cycle signal must be converted into a PWM signal using a PWM generator and then applied to the main switch. The central control device 20 can include this PWM generator or be connected to it. In another embodiment, the unified control signal Ctrl can also be the switching signal itself, so that the unified control signal Ctrl can be applied directly to the main switch of each DC-DC converter to control its switching operation.

[0049] In another embodiment, the uniform control signal Ctrl is a switching frequency signal. With certain types of DC-DC converters (for example, LLC or CLLC converters), the gain of the DC-DC converter can also be adjusted by setting the switching frequency, thereby influencing the output voltage.

[0050] Fig. Figure 4 shows a block diagram of the voltage feedback control module 211 of the central control device 20 according to an exemplary embodiment of this invention.

[0051] The voltage feedback control module 211 comprises a subtractor 2111 and a first proportional-integral controller 2113. The subtractor 2111 receives the measured individual output voltage V from the voltage sensor of one of the DC-DC converters. OUT_1 and also receives the individual setpoint voltage V defined in the current circuit topology. OUT_1setConsequently, the subtractor 2111 can supply the single output voltage V OUT_1 with the individual target voltage V OUT_1set The voltage deviation signal ΔV is compared to obtain the voltage deviation signal ΔV, which can then be provided to the first PL controller 2113. The first PL controller 2113 uses this voltage deviation signal ΔV to calculate the required duty cycle signal Uctrl. This duty cycle signal Uctrl is then provided, for example, to the PWM generator to convert it into a switching signal suitable for actuating the main switch of the DC-DC converters.

[0052] In this embodiment, the voltage feedback control module 211 optionally includes a voltage-to-duty-rate converter 2112, wherein this voltage-to-duty-rate converter 2112, for example, uses the formula for the relationship between input and output voltage to convert the voltage deviation signal ΔV into the duty-rate difference ΔD and then uses this duty-rate difference ΔD as input for the first PI controller 2113. This preliminary conversion is advantageous for the parameter optimization process of the first PI controller 2113 and reduces the setup time.

[0053] In this embodiment, the voltage feedback control module 211 can optionally include an anti-windup component 2114. The anti-windup component 2114 serves, for example, to limit the output of the first PL controller 2113 in response to the activation of a current feedback control module 213 in the central control device 20. For example, the anti-windup component 2114 can receive the status signal Trig from the current feedback control module 213 and, if this status signal Trig reflects that the current feedback control module 213 is activated, the anti-windup component 2114 can consequently dynamically adjust the output of the first PL controller 2113 by resetting the integral component, suspending the updating of the integral component, and / or limiting the integral component.For example, the anti-windup component 2114 can set the output Uctrl of the first PL controller 2113 to the last calculated output Limt, so that the newly calculated output Uctrl is limited to this value Limt. This prevents the integral component of the first PL controller 2113 from increasing further due to the current feedback control and thus avoids integral windup. In this way, a conflict with the goal of the current feedback control is avoided. Once the current feedback control module 213 is no longer active, the anti-windup component 2114 can allow the output of the first PL controller 2113 to be adjusted based on the new voltage deviation signal ΔV (or the duty cycle difference ΔD) to continue performing the control task.

[0054] In this embodiment, the integral component of the first PL controller 2113 in the voltage feedback control module 211 can be assigned a negative initial value (for example, -1). This allows the duty cycle to be caused to increase slowly from a relatively low value when the system starts, effectively limiting the current flow through the individual DC-DC converters and thus reducing the risk of overcurrent.

[0055] It should be noted that this is done using Fig. 4 presented voltage feedback control module 211, although based on the single output voltage V OUT_1 one of the DC-DC converters and the individual setpoint voltage V OUT_1setthe voltage feedback control signal is generated. However, given a suitable topology (for example, an IPOP or ISOS topology of the multiple DC-DC converters), the voltage feedback control module 211 can also use the unit formed by the multiple DC-DC converters as a control reference and, based on the total output voltage V, OUT and the total target voltage V OUT_set generate the voltage feedback control signal, whereby the structural design of the control loop with the from Fig. 4 is essentially comparable and is therefore not described again here.

[0056] In this embodiment, the function of the voltage feedback control module 211 was explained using a voltage feedback control signal in the form of a duty cycle signal. However, the voltage feedback control module 211 is not limited to generating only one specific type of voltage feedback control signal; it can also be used, for example, to generate a voltage feedback control signal in the form of a frequency signal for a switching signal.

[0057] Fig. Figure 5 shows a block diagram of the feedforward control module 212 of the central control device 20 according to an exemplary embodiment of this invention.

[0058] The feedforward control module 212 can, for example, use the measured individual input voltage V from the voltage sensor of one of the DC-DC converters. IN_1 received, the individual target voltage V OUT_1setCapture the values ​​and use these two as inputs. To capture the individual target voltage V OUT_1set The feedforward control module 212 receives the total target voltage V (for example, via an ECU query from the vehicle). OUT_set on the output side, where in certain topologies this total set voltage V OUT_set into the individual setpoint voltage V OUT_1set can be converted from a single DC-DC converter.

[0059] Subsequently, the feedforward control module 212 can generate the feedforward control signal PreCtrl according to the transfer function component 2120. The transfer function component 2120 can include a calibration function f(x) that describes the desired input-output relationship. In one embodiment, this transfer function can be as follows: f(x)=VIN_1VIN_1+Vout_1setTr where V IN _1 the single input voltage of one of the DC-DC converters is, V out_1setThe individual setpoint voltage of one of the DC-DC converters is , and Tr is the turns ratio of one of the DC-DC converters. In other cases, this transfer function f(x) can also take into account the compensation of the voltage drop caused by the internal resistance in the DC-DC converter. Depending on the specific type of DC-DC converter used, the aforementioned transfer function may differ.

[0060] It should be noted that this is done using Fig. 5 presented feedforward control module 212, although based on the single input voltage V IN_1 one of the DC-DC converters and the individual setpoint voltage V OUT_1setthe feedforward control signal is generated. However, given a suitable topology (for example, an IPOP or ISOS topology of the multiple DC-DC converters), the feedforward control module 212 can also use the unit formed by the multiple DC-DC converters as a control reference and, based on the total input voltage V, IN and the total target voltage V OUT_set generate the feedforward control signal, whereby the structural design of the control loop is based on the one from Fig. 5 is essentially comparable and is therefore not described again here.

[0061] Fig. Figure 6 shows a block diagram of the current feedback control module 213 of the central control device 20 according to an exemplary embodiment of this invention.

[0062] The current feedback control module 213 comprises a first subtractor 2131 and a second subtractor 2132. The first subtractor 2131 calculates the first difference between the output limit current I OUT_lim and the individual output current I OUT_1 One of the DC-DC converters. The second subtractor, 2132, calculates the second difference between the input limiting current I. IN_lim and the single input current I IN_1 one of the DC-DC converters. Furthermore, the first difference and the second difference can be amplified by a proportional amplifier (not shown). A comparison and selection component 2133 compares the two differences and selects the smaller one. The selected difference is input to the second PI controller 2134, whereupon the second PI controller 2134 outputs a corresponding current feedback control signal Ictrl to ensure that the individual input current I IN_1and / or the individual output current I OUT_1 the corresponding limiting current I IN_lim and I OUT-lim do not exceed.

[0063] In this embodiment, the current feedback control module 213 can further comprise an integral component limiter 2135. The integral component limiter 2135 serves to set the upper limit of the integral component of the second PL controller 2134 to zero. Optionally, the integral component limiter 2135 also serves to set the lower limit of the integral component of the second PL controller 2134 to a negative value, whereby the specific value of this lower limit can be determined, for example, based on empirical values, or determined based on the specific design parameters of the voltage feedback control module 211 and the feedforward control module 212, or dynamically determined based on the output results of the voltage feedback control module 211 and the feedforward control module 212.For example, the lower limit of the integral component here is the sum of the duty cycle generated by the feedforward control module 212 and the duty cycle generated by the voltage feedback control module 211, which is then multiplied by -1 to ensure that when superimposed with the duty cycle of the current loop, the value of the output total duty cycle is not less than 0. Consequently, the integral component limiter 2135 limits the output when the single input current I. IN_1 and / or the individual output current I OUT_1 , smaller than their respective limiting currents I IN_lim , I OUT_lim are the upward integration of the integral part of the second PL controller 2134, where the output of the second PL controller 2134 is zero at this time. Are the single input current I IN_1 and / or the individual output current I OUT_1 greater than their respective limiting currents I IN_lim , I OUT_limIt allows the second PL controller 2134 to integrate downwards and output a negative value, as long as this value does not fall below the lower limit of the integral component. The integral component limiter 2135 ensures that the current feedback control module 213 is only activated when the current of the DC-DC converters exceeds the limit value. This allows the system to react more precisely to current changes and, to a certain extent, prevents conflicts between the current feedback control module 213 and the voltage feedback control module 211.

[0064] Fig. 7A and Fig. Figure 7B shows a block diagram of the voltage equalization module 221 according to an exemplary embodiment of this invention.

[0065] In the Fig. 7A and Fig. 7B is the voltage equalization module as a unit with the one in Fig. The modification module 224 shown in Figure 3 is constructed. This means that the voltage balancing module 221 is configured to adjust based on the deviation ΔV0 between the individual input voltages V. IN_1 , V IN_2 A voltage compensation control signal Crr is generated by at least two DC voltage converters, and the unified control signal Ctrl generated by the main control module 21 is superimposed with the voltage compensation control signal Crr to modify the unified control signal Ctrl.

[0066] In the embodiment from Fig. For example, the voltage balancing module 221 comprises two subtractors 2211 and 2213, a PL controller 2212, and an adder 2214. The first subtractor 2211 is used to calculate the deviation ΔV0 between the individual input voltages V. IN_1 , V IN_2of at least two DC-DC converters. Ideally, this deviation ΔV0 is zero. In systems with only two DC-DC converters, if the deviation ΔV0 is zero, it means that the "midpoint voltage" of the two DC-DC converters on the input side is exactly half of the total input voltage V. IN This corresponds to the following. Here, at least two DC-DC converters can, for example, comprise a single DC-DC converter serving as a "control reference" for generating the uniform control signal and another DC-DC converter. The at least two DC-DC converters can also comprise any two DC-DC converters. The PL controller 2212 receives the deviation ΔV0 output by the first subtractor 2211 and generates the voltage compensation control signal Crr based on this deviation ΔV0.

[0067] In the embodiment from Fig. In section 7A, the output of the PL controller 2212 is divided into two independent paths, each performing different mathematical operations to achieve specific control objectives. The voltage compensation control signal Crr output on one path is superimposed with the uniform control signal Ctrl by the adder 2214 and then supplied to DC-DC converters with relatively high single-input voltages to reduce their output power. The voltage compensation control signal Crr output on the other path is subtracted from the uniform control signal Ctrl by the second subtractor 2213 and then supplied to DC-DC converters with relatively low single-input voltages to increase their output power.This allows the unified control signal Ctrl to be modified in different directions for various DC-DC converters. A negatively compensated unified control signal Ctrl" can be applied to at least one DC-DC converter, and a positively compensated unified control signal Ctrl' can be applied to at least one other DC-DC converter. In this way, only the duty cycle and / or frequency of a converter's switching signal needs to be adjusted based on a single unified control signal, thus simplifying the control logic and reducing complexity. This reduces the system instability caused by applying different duty cycles and / or switching frequencies to the individual DC-DC converters.

[0068] In the embodiment from Fig. 7B uses the adder 2214 to directly perform an addition (or subtraction) process between the voltage compensation control signal Crr output by the PI controller 2212 and the unified control signal Ctrl. The modified unified control signal Ctrl' (or Ctrl") is then used to control one of the DC-DC converters, while the unmodified unified control signal Ctrl continues to be used to control the other DC-DC converter. In this way, the operating state of each DC-DC converter can be fine-tuned based on a single unified control signal, thereby improving the overall system efficiency.

[0069] Fig. Figure 8 shows a block diagram of the current balancing module 222 according to an exemplary embodiment of this invention. The voltage balancing module 222 is configured to adjust the voltage based on the deviation ΔI0 between the individual input currents I IN_1 , I IN_2 A current compensation control signal Crr is generated by at least two DC voltage converters and the uniform control signal Ctrl is modified by superimposing the uniform control signal Ctrl generated by the main control module 21 with the current compensation control signal Crr.

[0070] Similar to the stress balancing strategy from the Fig. 7A and Fig. 7B, the current balancing module 222 can also include two subtractors 2221, 2223, a PL controller 2222, and an adder 2224. The first subtractor 2221 is used to calculate the deviation ΔI0 between the individual input currents I IN_1 , I IN_2of at least two DC-DC converters. The PI controller 2222 receives the deviation ΔI0 output by the first subtractor 2221 and generates the current compensation control signal Crr based on this deviation ΔI0.

[0071] In the embodiment from Fig. In section 8, the output of the PI controller 2222 is divided into two independent paths, each performing different mathematical operations to achieve specific control objectives. The Crr output on one path is superimposed with the unified control signal Ctrl by the adder 2224 and then supplied to DC-DC converters with relatively low single-input currents to increase their output power. The Crr output on the other path is subtracted from the unified control signal Ctrl by the subtractor 2223 and then supplied to DC-DC converters with relatively high single-input currents to decrease their output power.In an embodiment not shown, only an addition (or subtraction) method can be used between the current compensation control signal Crr output by the PI controller 2222 and the unified control signal, whereupon the modified unified control signal Ctrl' (or Ctrl") is provided to one of the DC-DC converters, while the unmodified unified control signal Ctrl continues to be applied to the other DC-DC converter.

[0072] Fig. Figure 9 shows a block diagram of the temperature compensation module 223 according to an exemplary embodiment of this invention.

[0073] The temperature compensation module 223 is configured to generate a temperature compensation control signal Crr based on the deviation ΔT0 between the operating temperatures T1 and T2 of at least two DC-DC converters. By superimposing the uniform control signal Ctrl generated by the main control module 21 with the temperature compensation control signal Crr, the uniform control signal Ctrl is modified. The temperature compensation module 223 can also generate a temperature compensation control signal Crr using two subtractors 2231 and 2233, a PI controller 2232, and a corresponding adder 2234. By superimposing this uniform control signal Ctrl with the uniform control signal Ctrl, the modified uniform control signals Ctrl' and Ctrl" are generated.For DC-DC converters with relatively low temperatures, the temperature compensation module 223 can provide a negatively compensated uniform control signal Ctrl"; for DC-DC converters with relatively high temperatures, it can provide a positively compensated uniform control signal Ctrl'. In an embodiment not shown, an addition (or subtraction) process can also be performed between the temperature compensation control signal Crr output by the PI controller 2232 and the uniform control signal. The modified uniform control signal Ctrl' (or Ctrl") is then provided to one of the DC-DC converters, while the unmodified uniform control signal Ctrl continues to be applied to the other DC-DC converter.

[0074] Unlike the compensation strategy from the Fig. 7A, Fig. 7B and Fig. Unlike the 8 (where a uniform power distribution is achieved by adjusting the input voltage or input current), the temperature compensation module 223 does not directly achieve a uniform power distribution. Instead, it takes into account the differences between the components caused by the manufacturing processes and performs the power distribution based on the device's own power output capability as reflected in its operating temperature. This prevents the heat load from concentrating in a DC-DC converter and thus avoids excessive heat loss. The temperature compensation module 223 ensures that two DC-DC converters reach their maximum operating temperature simultaneously, thereby achieving the maximum power output of the overall system.

[0075] Due to the difference between the aforementioned compensation strategy and the control objective, the temperature compensation module 223 cannot operate simultaneously with the voltage or current compensation module 222 in order to avoid conflicts regarding the control objective. Consequently, the central control device 20 can further be configured such that, while it modifies the unified control signal using the temperature compensation module 223, modification of the unified control signal using the voltage compensation module 221 and / or the current compensation module 222 is disabled.

[0076] Fig. Figure 10 shows a flowchart of the method for controlling several DC-DC converters according to an exemplary embodiment of this invention. This method comprises step S1 and step S2 and can be used, for example, when employing the [missing information] Fig. The DC voltage converter system 1 shown in 1A will be implemented.

[0077] In step S1, a uniform control signal is generated by the central control device 20 using one of the DC voltage converters as a control reference or using the unit formed by the several DC voltage converters as a control reference.

[0078] In step S2, the central control device 20 is used to jointly control the aforementioned multiple DC voltage converters based on the uniform control signal, so that the total output voltage of the aforementioned multiple DC voltage converters approaches the total setpoint voltage.

[0079] The process of executing each step has already been explained in detail in the preceding description with regard to the system and will not be repeated here. Furthermore, the details, features, advantageous designs, and technical benefits discussed in the preceding description in connection with the system can also be implemented in the computer program product and / or method presented here, and vice versa.

[0080] Fig. Figure 11 shows in schematic form the process of passive compensation of the input voltages of the several DC voltage converters according to an exemplary embodiment of this invention.

[0081] In this embodiment, two DC-DC converters have a topology in which the inputs are connected in series, the time course of the change of their respective individual input voltage V IN_1 , V IN_2 is in Fig.Figure 11 is shown in curve form. In the initial phase of the system's control, the duty cycle of the DC-DC converters is relatively low and the equivalent impedance is relatively high, and at this point, the effect of the internal resistance of the voltage sampling circuit on the overall system cannot be neglected. Consequently, the difference between the individual input voltages V IN_1 , V IN_2 The voltages of the first and second DC-DC converters are initially relatively large. As the regulation progresses, after a certain period of passive system stabilization, the individual input voltages V approach each other. IN_1 , V IN_2The two DC-DC converters gradually reach a stable state and eventually maintain similar voltage levels. Once stable, the voltage deviation ΔV0 between the two is possibly caused by manufacturing tolerances and can be compensated for using the previously described equalization process.

[0082] It is understandable that the methods of the individual embodiments of this disclosure can be implemented by computer programs / software. This software can be loaded into the working memory of a processor and, when executed, perform a method according to the embodiments of this disclosure.

[0083] According to a further embodiment of the present disclosure, a computer program product is provided with program code units, wherein the program code units are configured to execute a method according to the embodiments of the present disclosure when the computer program product is executed on a computer or when stored on a computer-readable storage medium (for example, CD-ROM). This machine-readable storage medium is, for example, an optical storage medium or a solid-state storage medium that is integrated into other hardware or supplied as part of other hardware.

[0084] Although the specific embodiments of the present invention have been described in detail herein, they are given only for the purpose of interpretation and should not be regarded as limiting the scope of the present invention. Various substitutions, modifications, and variants can be conceived without departing from the spirit and scope of the invention.

Claims

[1] DC-DC converter system (1), wherein said DC-DC converter system (1) comprises the following: Several DC-DC converters (51, 52), each DC-DC converter comprising one input and one output, wherein the inputs of said several DC-DC converters (51, 52) are all connected in series or in parallel with each other, and the outputs of said several DC-DC converters (51, 52) are all connected in series or in parallel with each other; and a central control device (20) configured to generate a uniform control signal using one of the DC voltage converters (51) as a control reference or using the unit formed by the multiple DC voltage converters (51, 52) as a control reference, in order to control the said multiple DC voltage converters (51, 52) jointly on the basis of the uniform control signal, so that the total output voltage of the said multiple DC voltage converters (51, 52) approaches the total setpoint voltage. [2] DC-DC converter system (1) according to claim 1, wherein said unified control signal is the duty cycle and / or frequency of the switching signal to be applied to the main switch of each DC-DC converter and the central control device (20) is configured to dynamically adjust the duty cycle and / or frequency of said switching signal. [3] DC-DC converter system (1), according to claim 1 or 2, wherein: • in an ISOS or IPOP topology of the multiple DC-DC converters (51, 52) using one of the DC-DC converters (51) as a control reference or using the unit formed by the multiple DC-DC converters (51, 52) as a control reference, the uniform control signal is generated; • in an ISOP or IPOS topology of multiple DC-DC converters (51, 52) using one of the DC-DC converters (51) as a control reference, the uniform control signal is generated. [4] DC-DC converter system (1) according to any one of claims 1 to 3, wherein the central control device (20) is configured such that: it provides the uniform control signal directly to the aforementioned multiple DC-DC converters in order to control the individual DC-DC converters together; or It modifies the uniform control signal based on the state deviation between at least two DC-DC converters, provides the modified uniform control signal to at least one DC-DC converter (51) and provides the modified or the unmodified uniform control signal to the remaining DC-DC converters (52). [5] DC-DC converter system (1) according to claim 4, wherein the central control device (20) is configured such that: they modify the uniform control signal for different DC voltage converters in different directions and apply a negatively compensated uniform control signal to at least one DC voltage converter (51) and apply a positively compensated uniform control signal to at least one other DC voltage converter (52). [6] DC-DC converter system (1) according to any one of claims 1 to 5, wherein the central control device (20) comprises a voltage feedback control module (211) and the voltage feedback control module (211) is configured to generate a voltage feedback control signal based on the deviation between the individual output voltage of one of the DC-DC converters (51) and the individual setpoint voltage or based on the deviation between the total output voltage of the unit formed by the multiple DC-DC converters (51, 52) and the total setpoint voltage, and the central control device (20) is configured to generate the unified control signal based on the voltage feedback control signal. [7] DC-DC converter system (1) according to claim 6, wherein the voltage feedback control module (211) comprises a first PI controller (2113) and an anti-windup component (2114), the first PI controller (2113) serving to output the voltage feedback control signal, and the anti-windup component (2114) serving to limit the output of the first PI controller (2113) in response to the activation of a current feedback control module (213) in the central control device (20); and / or wherein the integral part of the first PI controller (2113) in the voltage feedback control module (211) is assigned a negative initial value. [8] DC-DC converter system (1) according to any one of claims 1 to 7, wherein the central control device (20) comprises a feedforward control module (212) and the feedforward control module (212) is configured to generate a feedforward control signal based on the individual input voltage of one of the DC-DC converters (51) and the individual setpoint voltage or based on the total input voltage of the unit formed by the multiple DC-DC converters (51, 52) and the total setpoint voltage, and the central control device (20) is configured to generate the unified control signal based on the feedforward control signal. [9] DC voltage converter system (1) according to any one of claims 6 to 8, wherein the individual setpoint voltage and the total setpoint voltage correlate with the topology of the multiple DC voltage converters (51, 52), wherein: • in an ISOS or IPOS topology of multiple DC voltage transformers (51, 52) the total setpoint voltage is a first preset value and the individual setpoint voltage corresponds to the total setpoint voltage divided by the number of DC voltage transformers; • in an ISOP or IPOP topology of the multiple DC voltage converters (51, 52) the total setpoint voltage is a second preset value and the individual setpoint voltage corresponds to the total setpoint voltage. [10] DC-DC converter system (1) according to any one of claims 1 to 9, wherein the central control device (20) comprises a current feedback control module (213) and the current feedback control module (213) is configured to generate a current feedback control signal based on the deviation between the individual input current and / or the individual output current of one of the DC-DC converters (51) and the limit current, and the central control device (20) is configured to generate the unified control signal based on the current feedback control signal. [11] DC-DC converter system (1) according to claim 10, wherein the current feedback control module (213) comprises a second PI controller (2134) and an integral component limiter (2135), the second PI controller (2134) serving to output the current feedback control signal, and the integral component limiter (2135) serving to set the upper limit of the integral component of the second PI controller (2134) to zero, so that if the single input current and / or if the single output current is less than the limit current, the output of the second PI controller (2134) is zero, and if the single input current and / or if the single output current is greater than the limit current, it is possible for the second PI controller (2134) to integrate downwards and generate a negative output. [12] DC-DC converter system (1) according to any one of claims 1 to 11, wherein the central control device (20) comprises: a voltage compensation module (221) configured such that: it generates a voltage compensation control signal based on the deviation between the individual input voltages of at least two DC-DC converters and by superimposing the uniform control signal with the voltage compensation control signal, the uniform control signal is modified; or a current balancing module (222) configured such that: it generates a current compensation control signal based on the deviation between the individual input currents of at least two DC-DC converters, and modifies the unified control signal by superimposing the unified control signal with the current compensation control signal; or a temperature compensation module (223) configured such that: it generates a temperature compensation control signal based on the deviation between the operating temperatures of at least two DC-DC converters, and The uniform control signal is modified by superimposing the uniform control signal with the temperature compensation control signal. [13] DC-DC converter system (1) according to claim 12, wherein the central control device (20) selects the compensation strategy based on the topology of the multiple DC-DC converters (51, 52) to modify the uniform control signal, wherein: • if the topology of the multiple DC-DC converters (51, 52) is an ISOS or ISOP topology, it selects the voltage equalization module (221) to modify the uniform control signal, and / or • if the topology of the multiple DC-DC converters (51, 52) is an IPOS or IPOP topology, it selects the current balancing module (222) to modify the unified control signal; wherein the central control device (20) is configured such that, while it modifies the uniform control signal using the temperature compensation module (223), the modification of the uniform control signal using the voltage compensation module (221) and / or the current compensation module (222) is disabled. [14] DC-DC converter system (1) according to any one of claims 1 to 13, wherein said DC-DC converter system (1) further comprises: a switching unit (30) configured such that by changing the switching state the inputs of the multiple DC voltage converters (51, 52) are switched so that they are all connected in series or all in parallel to each other, and / or the outputs of the multiple DC voltage converters (51, 52) are switched so that they are all connected in series or all in parallel to each other; wherein the central control device (20) is further configured to determine the topology of the multiple DC voltage converters (51, 52) based on the current switching state of the switching unit (30) and to generate the uniform control signal based on the determined topology. [15] DC / DC converter system (1) according to any one of claims 1 to 14, wherein said multiple DC / DC converters (51, 52) are all designed as DC / DC flyback converters with active clamp. [16] Method for controlling multiple DC-DC converters (51, 52), wherein said method is carried out using a DC-DC converter system (1) according to any one of claims 1 to 15 and said method comprises the following steps: Generating a uniform control signal using one of the DC-DC converters (51) as a control reference or using the unit formed by the multiple DC-DC converters (51, 52) as a control reference; and common control of the said multiple DC voltage converters (51, 52) based on the unified control signal, so that the total output voltage of the said multiple DC voltage converters (51, 52) approaches the total set voltage. [17] Computer program product comprising program code units, wherein said program code units are configured to cause said computer to execute the method according to claim 16 when the computer program product is executed on a computer or when stored on a computer-readable storage medium.

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