Energy system and configurable energy system with heterogeneous energy storage and associated control

Abstract

The invention relates to an energy system (30) and a control unit (10) for an energy system (30) for controlling various operating modes of the energy system (30), having two energy modules (22) and at least two switching units (24), comprising a clock generator (12) for generating a plurality of temporally offset carrier signals (121), a signal generator (14) for generating a reference signal (141), an energy generator (16) for generating an offset signal (161) and an output interface (18) for outputting a control signal for switching at least one of the switching units (24) of the energy system (30) in such a way that the energy modules (22) are switched into a predetermined operating mode. The control unit (10) is designed and configured to generate the control signal on the basis of at least the reference signal (141) of the signal generator (14). The invention also relates to a corresponding method.

Description

[0001] Rhineland-Palatinate University of Technology Kaiserslautern-Landau (RPTU)

[0002] Energy system and configurable energy system with heterogeneous energy storage and associated control

[0003] The present invention relates to a control unit for controlling different operating modes of an energy system with two energy modules and two switching units, as well as to a configurable energy system with two energy modules, two switching units and two lines connecting the switching units and with an inductance arranged between the energy modules.

[0004] Dynamically configurable batteries or dynamic reconfigurable batteries, also known as smart batteries, have evolved significantly in recent years. Numerous topologies and control mechanisms exist for these batteries, enabling parallel connection of individual modules, sensorless balancing, improved output quality, and higher efficiency than previous generation batteries. Smart batteries make them an interesting alternative for many applications in electromobility, but also for grid storage applications. Such batteries are usually modular in design, meaning they comprise multiple battery modules interconnected accordingly. The battery modules, which themselves usually contain one or more battery cells, are typically connected in series and / or parallel.Batteries or energy systems are an expensive component of a system, such as an electric vehicle; it is therefore desirable to be able to use battery units with different configurations, chemical compositions, or parameters while still retaining the typical advantages of smart batteries. Current battery systems require all battery modules to be of the same type and have the same parameters, configurations, and chemical compositions. For this reason, the applicability of the modular batteries known to date is limited.

[0005] Some topologies and controllers based on asymmetrically modular multilevel converters (AMMCs) allow the use of modules and battery modules with different voltages and voltage levels, as well as different capacities. However, such topologies require relatively large inductors to limit the energy transfer rate between the battery modules in parallel operation. This increases the cost, size, and output bandwidth of the converter. Furthermore, the control of the energy transfer is coupled to the output regulator, making the development of a stable regulator very difficult.

[0006] While known smart DC batteries offer many desirable advantages, such as improved flexibility, higher controllability due to additional degrees of freedom, better output quality, and easy scalability, they are nevertheless limited to either series mode and / or bypass mode without energy transfer between the individual battery modules and / or to identical battery modules. In particular, the use of identical battery cells in the battery modules with the same energy content, same performance, and same aging results in suboptimal and difficult solutions for many applications with highly fluctuating loads. Mixing different battery types with their different properties would be highly desirable, but due to the different discharge curves in state-of-the-art solutions, this is either not possible or completely uncontrolled in charging and discharging.

[0007] However, in many use cases, it is desirable to reduce the cost, volume, and weight of batteries and battery modules while maximizing their capabilities and performance. This is particularly important in electric vehicles or large-scale network storage applications, where the battery represents a large and expensive part of the system.

[0008] The current state of the art therefore indicates a need for energy modules or battery modules that can be used with different configurations, different chemistries, or parameters without losing the typical advantages of smart DC batteries. This creates a need for improved configurable energy systems and corresponding controllers.

[0009] The present objects are achieved by a control unit having the features of claim 1, as well as by a configurable energy system having the features of claims 9 and 10 and by a method for controlling different operating modes of an energy system having the features of claim 19.

[0010] In a first aspect, the invention relates to a control unit for an energy system for controlling different operating modes of the energy system having two energy modules and two switching units. The control unit is designed and configured to generate the control signal based on at least the reference signal of the signal generator. The control unit has the advantage that it can control and influence the energy system having two energy modules and two switching units such that different operating modes can be adopted. The operating modes of the energy system can therefore be changed. This allows, on the one hand, the energy provided to be changed, for example by adjusting the external voltage or the output current by changing the operating modes, and to exchange energy between the energy modules. On the other hand, this makes it possible to control an energy system that has different energy modules.

[0011] A typical example of a controlled energy system could be a battery comprising multiple energy modules or battery modules. Using the control unit, it is possible to construct a battery with different battery modules. The individual energy modules can therefore differ in their parameters, for example, they can be based on different chemical compositions. For example, it is possible to combine a lithium cobalt oxide battery module with a lithium manganese oxide battery module. Furthermore, it is possible to use lithium iron phosphate and mixed types of the aforementioned, metallic lithium cells (instead of intercalation electrodes), solid-state electrolyte cells (with very different discharge curves), sodium battery types, and in the future, aluminum battery types (high capacity but, at least for the time being, significantly lower performance).If the energy system includes multiple energy modules, other energy modules or energy storage modules can be used in addition to battery modules. An energy module is defined as an active energy element that can be a source or sink of electrical energy, or both. The energy module offers the possibility of storing several watt-hours of energy, with storage possible over a longer period of at least several hours or days.

[0012] Heterogeneous modules offer the possibility of using battery modules with high energy density but low power in combination with modules with high power density but low energy density. The combination of several energy modules with different parameters such as power density (parameter A), energy density (parameter B), different temporal aging depending on the voltage, e.g., in the form of a time constant and / or critical voltage (so-called calendar aging, parameter C), different cyclic aging profiles (parameter D), different voltage profiles (parameter E), costs (parameter F), etc. would be possible according to the invention. To describe the modules and parameters A, B, C,..., the parameters can be represented as vectors, where the first indices (a1, b1, c1,...) represent the characteristics / parameters of the first type of energy module, and the second indices (a2, b2, c2,...) represent the characteristics / parameters of the first type of energy module.) denote the characteristics of the second type of energy modules, and so on. Therefore, vector A should be a vector with NT. YP indices, where N typ is the number of different types of energy elements.

[0013] This allows the behavior of the energy system to be adjusted according to the desired behavior or performance profiles (here defined as G op t) can be optimized without the typical disadvantages of the state of the art. Here, Go P t is a vector with N typ Indices, where the first index (g op i) corresponds to the parameter or characteristics relevant to A, the second index (g 0P 2) corresponds to the parameter or features relevant to B, and so on. The vector G op t defines the preferred or ideal properties of the energy module for the specific application.

[0014] Preferably, in addition to the above-mentioned parameters, the different energy modules each have a different voltage or a different voltage profile, wherein the voltage profile preferably represents the voltage over the charge state or the voltage influence of current and / or temperature.

[0015] Therefore, an energy system can be designed from these heterogeneous energy modules, which can balance and compensate the different properties against each other in order to optimize at least one of these parameters beyond the properties that a single energy type can offer.

[0016] The resulting system with modules having the above-mentioned parameters may preferably have the following properties. where Wi is the vector of the quantities of the individual types of energy modules used. Accordingly, the vector Wi can be controlled or optimized according to the invention to achieve a specific combination of parameters or properties defined by the vector G op t are defined. Here, Gsys is the vector of parameters and properties of the resulting energy system using each type of energy module with the quantities specified in W1.

[0017] The optimization function can be formed, for example, by: where the value of the vector W1 is determined to be the difference between G op t and Gsys to be determined. G sys is the above system function. W2 is the priority of each parameter to be optimized.

[0018] According to a further aspect, the present invention relates to a configurable energy system having at least two energy modules, at least two switching units, two connections connecting the switching units, and an inductance arranged between the energy modules. The energy system further comprises a control unit for controlling different operating modes of the energy system. The control unit has a clock generator for generating a plurality of time-offset carrier signals, a signal generator for generating a reference signal, and an energy generator for generating an offset signal. The control unit is designed to generate a control signal, which is output to at least one of the switching units of the energy system via an output interface of the control unit in order to control or switch the switching unit.The control signal is designed such that the two energy modules can be switched to a predetermined operating mode or that an operating mode of the energy system can be changed by switching from a first operating mode to a second operating mode. The control signal generated by the control unit is based on the carrier signal, the reference signal, the offset signal and / or a combination of reference signal and offset signal or a combination of the three signals, wherein a combination of the three signals is also understood to mean the comparison of two or a combination of two signals with a third signal. Switching the switching unit comprises switching a switch of the switching unit or changing a switching state of the switching unit.Controlling the switching unit includes changing the state of the switching unit, controlling elements or switches of the switching unit or switching several switches of the switching unit, even to different switching states.

[0019] The control signal is used to connect the two energy modules to each other in different operating modes, thereby switching the entire energy system to a single operating mode. For example, it is possible to connect the two energy modules in a serial mode using the control signal, so that the two energy modules are connected in series. Connecting the two energy modules in series in this way is referred to as the series mode of the energy system. The same applies, for example, to a parallel mode of the energy system.

[0020] The control unit is preferably designed and configured to switch the energy modules of the energy system into the operating modes bypass mode, series mode and parallel mode as well as into a hybrid mode comprising a combination of parallel mode and series mode, boost mode or bypass mode.

[0021] The invention has the advantage that different energy modules can be combined with one another in a system. Energy modules in this sense also include battery modules or energy modules with battery cells. Different battery types can be used in the combinable modules in an energy system. In this case, the energy system contains one or more heterogeneous batteries with different modules or energy modules.

[0022] Different battery types can also be: lead-acid (low energy and power density, cheap, environmentally hazardous, high abuse tolerance), nickel-cadmium, nickel-metal hydride, Li-ferrous sulfate (LFP for short, power, hardly any capacity, low fire hazard, high charge and discharge rate, lower energy density, low abuse tolerance), Li-nickel-manganese-cobalt (high energy density, fire hazard), lithium-cobalt oxide (LCO for short, good energy density, good voltage, expensive), metallic Li, sodium-ion batteries (abundant raw material, low voltage, low energy density, potentially cheaper), solid-state electrolyte cells (higher safety, low flammability, non-volatility, mechanical and thermal stability), mixed types, other admixtures in electrodes, cathode and anode chemistry, etc.

[0023] A further aspect of the invention relates to an energy system with at least two energy modules, two switching units, two connections connecting the switching units, and at least one inductor arranged between the energy modules. The energy system is characterized in that the (at least) two energy modules can be battery modules that are different and, in addition to a different voltage or a different voltage profile, have at least one other different parameter. The parameter belongs to the following group of elements or features and preferably includes at least: discharge curve, power density, chemical composition, energy density, predetermined aging voltage, cyclic aging profile, or battery type.This energy system or battery system therefore also has the advantages mentioned above and can, for example, be constructed from the battery types mentioned above or comprise modules of these battery types. The same applies to energy modules that are not battery modules. Further aspects of the invention relate to a corresponding method for controlling different operating modes of an energy system with two energy modules and two switching units coupled to the energy modules, as well as to a computer program product with program code for carrying out the steps of the method when the program code is executed on a computer. Further aspects relate to a storage medium on which a computer program is stored which, when executed on a computer, effects execution of the method described therein. A further aspect relates to a vehicle with an energy system described above.

[0024] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or even individually, without departing from the scope of the present invention. In particular, the method and the computer program product can be implemented according to the embodiments described for the control unit and for the energy system in the dependent claims.

[0025] The control unit according to the invention and the method enable complete control of the power system's performance as well as the energy transfer between the energy modules of the energy system. The energy system topology presented here can offer all the advantages of smart batteries. However, unlike conventional battery systems, the energy system does not rely on all energy modules being identical, i.e., of the same type and having the same parameters.

[0026] Within the scope of the invention, it was recognized that in batteries in energy systems with at least two energy modules and at least one, preferably at least two switching units, a connection exists between the two energy modules. Typically, the connection between the two modules is designed such that a connection exists between the two switching units and the switching units are each connected to the associated energy modules. The connection between the switching units has an inductance, which is formed either by the parasitic line capacitance or via inductors or other inductive components, which offers the advantage that the inductance can be determined and specified.It has been recognized that mutual inductances, also called mutual or push-pull inductances, can store energy and establish a relationship between the current, or more precisely, the temporal change in the current, and the voltage difference between two (particularly adjacent) modules in certain module states. The invention utilizes this relationship to specifically control the energy transfer between two energy modules and, through suitable control, to maintain or specifically adjust desired constant voltage differences, e.g., due to different discharge curves of batteries or battery types. Although the inductors used represent a significantly lower, sometimes negligible, common-mode inductance, they also exhibit a non-negligible differential inductance (mutual inductance).The control unit according to the invention thus enables energy transfer between the individual energy modules and can control them independently of one another without influencing the output behavior of the energy system.

[0027] In contrast to known energy systems, the energy system according to the invention enables the use of storage modules or energy modules with different properties, in particular different energy or a different energy-to-power ratio. The energy system according to the invention also allows parallel operation with a mixture of different energy modules, in which the energy of the load is distributed among the modules.

[0028] Previously known energy systems with a form of energy exchange between modules either require different methods for controlling the energy exchange or have separate energy exchange circuits. The inventive energy system proposes a modulation method combined with topologies that combines the advantages of both parallel circuits (the load energy is shared between the modules, resulting in better efficiency and a lower need for energy balancing) and structures in which the modules can readily exchange energy with each other (not in buck-boost mode, but in boost-boost mode). The energy system is thus suitable for energy modules with different characteristics, not only in terms of voltage, but also in terms of power limit, energy capacity, and impedance, among others.

[0029] In the prior art, for example, from FANG, J. et al., A Review of Multilevel Converters With Parallel Connectivity; IEEE on Power Electronics; 2021, ol. 36, Issue 11; Journal Article, a power system designed as a step-down cascade boost converter is known which, with switched chokes between the modules, can operate switched inductors as DC-DC converters independently of the main current path of the load. This means that the switches used ultimately have different switching speeds. In contrast, according to the invention, the two processes (controlling the output voltage, distributing the load current between the modules and simultaneous controlling the energy transfer rate) are preferably combined in a single process. The switching rate of the modules is not changed.

[0030] In a preferred embodiment of the invention, the switching pattern, which differs significantly from all power systems known in the prior art, is changed. While normally only the parallel and boost modes are present, the invention also includes a bypass mode, which enables lower induction requirements and / or reduces current ripple. While the power systems known in the prior art, such as those described in FANG, J. et al., in CN 110912405 B or in RIVERA, Z. et al.; Modular Multilevel Series / Parallel Converter With Switched-Inductor Energy Transfer Between Modules; IEEE Transaction on Power Electronics, 2019, Vol. 34 Issue 5, Journal Article, essentially relate to identical modules with different voltages, other characteristics, e.g. age, chemistry, energy density, battery type, etc., are not addressed. However, according to the invention, energy exchange between the modules can be achieved.The control unit according to the invention and the corresponding method can generate predefined switching patterns.

[0031] For example, topologies with multiple modules are disclosed in FANG, J. et al. However, these only allow balancing via the load current, not directly controlling the energy exchange between the modules. Furthermore, optimization as described above is neither planned nor possible.

[0032] CN 110912405 B is limited to unidirectional operation. It discloses only a fixed buck / boost converter with an inductor, in which an intermediate state (similar to a buck-boost mode) can only be achieved in a short transition time between buck and boost operation. A bias voltage is set according to the voltage of the two modules. It is neither intended nor possible to regulate the bias voltage between the modules. In contrast, the invention provides for bidirectional boost operation (boost mode) without buck operation.

[0033] The present invention makes it possible to realize different control and switching patterns and to carry out their optimization.

[0034] In contrast to the invention, the prior art does not allow for control of the load voltage and the energy transfer rate between two modules. It only attempts to replace the bypass modes of the modules with a parallel mode. However, there is no way to control the energy transfer rate between the modules as described in the invention.

[0035] In a preferred embodiment of the control unit, the output interface has two outputs to which the control signal is applied and output. Particularly preferably, a plurality of control signals are generated so that each of the outputs outputs a control signal. Very preferably, different control signals are generated so that each of the outputs can output a different control signal. A particularly preferred embodiment provides that one of the outputs is coupled to one of the switching units and another output to another switching unit. In this way, a switching unit can be switched with each of the outputs. In preferred embodiments, the control signal output via the output interface can have a plurality of signal components so that a plurality of switches in a switching unit can be controlled.In this way, it is possible to address and switch individual switches in switching units using the control signals generated in the control unit.

[0036] In a preferred embodiment of the energy system, the switches of the switching unit are designed as a switching circuit, wherein the switching circuit has at least one low-resistance state with an impedance of less than 1 ohm, preferably less than 0.1 ohm, particularly preferably less than 0.01 ohm, and a high-resistance state in which the impedance is more than 1 megaohm, preferably more than 10 megaohms, particularly preferably more than 100 megaohms. Another preferred embodiment of the switching units of the energy system provides switches that are transistors. Very preferably, FET transistors, MOSFET transistors, bipolar transistors, IGBTs, GaN transistors, or thyristors are used. Alternatively, these transistors can also be combined. In an advantageous embodiment of the switching units, the switching unit comprises at least one diode. In some applications, it is expedient for at least one diode to be combined with a switch in the switching unit.Of course, several diodes and several switches can also be provided in one switching unit.

[0037] In a preferred embodiment, the control unit has an output interface with at least three outputs. The first output of the output interface is preferably configured to output control signals to switch the energy modules of the energy system into a series mode. The second output of the output interface is preferably configured to switch the energy modules into a parallel mode, so that at least two energy modules are connected in parallel. The third output is preferably configured to switch the energy system into a boost mode, in which energy can be transferred from one of the energy modules of the energy system to an inductor (i.e., charging the inductor in a specific direction, i.e., from a predetermined energy module), which can then be transferred to an adjacent module in parallel mode.Boost mode is therefore a mode that, at least temporarily, resembles a charging mode, and in which the inductance between two adjacent power modules can be charged. During a subsequent period (e.g., the remaining time while boost mode is active), the inductance can then be discharged, which can occur, for example, in a parallel mode of the modules via the charged inductance and / or in a charge hold mode. Preferably, a voltage increase or step-up conversion occurs in boost mode.

[0038] With the combination of boost mode and parallel mode (a possible variant of hybrid mode), energy is transferred from one energy module with a higher energy level to another with a lower energy level, for example, to equalize the energy levels of the two modules. This makes it possible to shift energy between the energy modules within the energy system. This is useful in some applications, for example, when an energy module needs to be charged that can quickly release its energy to the outside, so that a consumer connected to the energy system can be supplied with a lot of energy in a short time.This can be the case, for example, if one of the energy modules is a certain type of battery or one of the modules can only supply energy, for example a PV module, which must be able to operate at maximum power, which may be higher than the load of the energy system.

[0039] Preferably, one or more energy modules can be PV modules of a photovoltaic system.

[0040] The predetermined operating modes that can be switched by means of the control signal include at least the series mode, in which the energy modules of the energy system are connected in series, and the parallel mode, in which the energy modules or battery modules are connected in parallel, as well as the boost mode, in which energy can be transferred from an energy module or battery module to an inductor, for example, to compensate for different voltage levels between the individual modules. Furthermore, an operating mode can be a bypass mode, in which the energy or battery modules are connected in such a way that, for example, one of the energy or battery modules is "bypassed," i.e., excluded from the power flow.

[0041] In a preferred embodiment, the control unit is designed and configured to switch the energy modules of the energy system into at least one of the desired operating modes, preferably into several operating modes, particularly preferably into all operating modes, despite different voltages in the individual energy modules.

[0042] Preferably, the hybrid mode comprises a combination of parallel mode and boost mode, a combination of parallel mode and series mode and / or a combination of parallel mode and bypass mode and / or another combination of two modes.

[0043] In the following, the terms energy system and battery are sometimes used synonymously, as are energy module, module, and battery module. While the battery is a special case of an energy system, within the scope of the invention, the terms battery and battery module should not be understood in a restrictive sense.

[0044] A preferred embodiment of the control unit is designed such that the control signal in the control unit is generated from the comparison of the carrier signal of the clock generator with the sum of the modulation signal and the reference signal. For example, the control signal can be formed from the carrier signal if the carrier signal is greater than the sum of the modulation signal and the reference signal. Of course, a selection the other way around is also possible. Alternatively and likewise preferably, the control signal can be formed from the comparison of the carrier signal with the modulation signal alone. For example, the control signal can be formed from the signal that is the larger of the two signals. It is also conceivable for the control signal to be formed from a weighted combination of the modulation signal, the reference signal and / or the carrier signal.For example, the control signal can be generated depending on the energy modules used in the energy system to be controlled.

[0045] A preferred embodiment of the control unit provides for the control of the energy modules using symmetrical dual modulation. Within the context of the invention, symmetrical dual modulation means that the reference signals corresponding to a specific module, which are compared with the corresponding carrier to determine the operating modes, are symmetrical with respect to the average modulation signal controlling the series mode. This is achieved by adding and subtracting the offset signal generated by the energy regulator (generator) from the modulation signal generated by the power regulator.

[0046] Alternatively, and equally preferred, a control unit is provided in which the energy modules are controlled using asymmetric dual modulation of the energy modules. A preferred embodiment of the control unit provides that a circular current is used as the controlled variable to generate the offset signal. The circular current is a measured current flowing between the energy modules. The circular current is a push-pull current flowing in the connections between the switching units or between two adjacent switching units. The circular current accordingly transports energy from at least one energy module to at least one other energy module.

[0047] In a preferred embodiment, the generation of the offset signal is based on the minimization of an error function, by means of which, for example, a difference between the measured circulating current and a reference current for the circulating current, a so-called reference circulating current, is minimized. Thus, the generation of the offset signal is preferably based on the measured circulating current and a reference current or reference circulating current, which can be predetermined and / or adjustable. The reference current or reference circulating current can be used, for example, to change the operating mode of the energy module, for example, to compensate for an energy imbalance between them, or to operate a PV module at maximum power.

[0048] In a preferred embodiment of the control unit, the reference signal is generated based on an output voltage measured across an energy module to be controlled. Alternatively, the output voltage measured across the energy system to be controlled can also be used. The energy system output voltage comprises all voltages of the energy modules connected together in the system, preferably those connected in series mode. Preferably, the generation of the reference signal and the determination of the reference signal are based on the minimization of an error function, wherein the generation of the reference signal is particularly preferably based on the measured output voltage as a controlled variable and a reference voltage or reference output voltage. In a preferred embodiment of the energy system, the energy system has multiple energy modules.At least two of the energy modules of the energy system are preferably different and have a different voltage or voltage profile. At least one additional parameter is different for the energy modules, with the parameters being selected from the group of the following: power density, energy density, predetermined aging voltage, cyclic aging profile, chemical composition, and different battery types. This list is not exhaustive; other parameters are conceivable.

[0049] In a preferred embodiment of the energy system, at least one of the energy modules is a rechargeable battery. Energy modules with non-rechargeable batteries are also preferred. If the energy modules are battery modules or batteries, one of the parameters for determining the type of energy module can also be the chemical composition and chemical elements of the battery, as well as the battery types.

[0050] An energy system with battery modules is also called a battery, smart battery, or configurable battery. In this case, different battery modules are interconnected (dynamically).

[0051] In a preferred embodiment of an energy system or battery system, the individual modules (energy module, battery module) can be connected in different operating modes; for example, two modules can be connected in parallel or in series. It is also possible to implement a bypass circuit so that one of the modules is electrically bypassed.

[0052] In a preferred embodiment of the energy system, at least one of the switching units comprises two switches. Preferably, several or all switching units each comprise two or more switches. Switching units with two switches each are preferred, with the switches very preferably being connected in series. Particularly preferably, a switch is connected in parallel to an energy module. Likewise preferably, a switch is connected between the two common-mode inductances of the lines between the energy modules. Further embodiments and arrangements of the switches in the switching units arise for specific applications. Some examples are explained in more detail with reference to the figures.

[0053] A preferred energy system has a control unit with an output interface that has multiple output ports. Very preferably, each output port is connected to a switch of the switching units, so that each output port controls and switches a switch of the switching units. In this way, the individual switches in the switching units can be controlled and switched individually. This makes it possible to switch different operating modes on, off, and toggle through an individual configuration of switching states. Some examples of this are explained using the figures. The necessary switching processes and switch combinations are familiar to those skilled in the art.

[0054] A preferred embodiment of an energy system provides that the at least two energy modules are connected in 2-quadrant mode. In a likewise preferred embodiment of the energy system, at least two energy modules are included, with the energy modules preferably being connected in 4-quadrant mode.

[0055] According to a further preferred embodiment of the energy system, the energy modules are different in that they have different parameters, different voltage levels, or, in the case of battery modules, are different battery types and / or comprise different chemical elements. Preferably, an energy module designed as a battery module comprises a rechargeable storage element, a non-rechargeable storage element, or a combination of both. Likewise preferred is an energy system with energy modules that comprise a PV module, a fuel cell, a supercapacitor, or a capacitor bank comprising multiple capacitors or capacitors, or a combination thereof or with battery modules.

[0056] The present invention therefore shows a solution that enables the use of different energy modules or battery modules with different properties without negatively affecting the applicability and / or feasibility of the energy system. Different properties here include different (usually fixed) series and parallel configurations of cells within modules and thus, for example, different voltages, chemistry types of the battery modules and / or internal parameters such as voltage, power or energy. The energy system or battery system according to the invention is based on mutual inductances that have a significantly low inductance for common-mode currents and thus also the output current on the one hand, and a high inductance for differential or differential mode currents. These differential mode currents are also referred to as circulating currents (circulating currents orCirculating currents (also referred to by those skilled in the art as circulating currents) between adjacent modules are generated by controlling the energy system for energy transfer between the modules. This makes it possible to adjust the output currents (common-mode currents) and the circulating currents (circulating current, differential-mode current) to desired configurations that enable controlled charge or energy transfer between adjacent modules. At the same time, at least one fully controlled output is generated by modulating the output voltage of the energy modules or battery module.

[0057] The circulating current can be measured from the difference between the currents of the two coupled inductors, which are passed through a bandpass or low-pass filter, e.g., a third- or fourth-order filter. The currents can be estimated from the voltage steps across the ohmic resistances of the storage elements. The voltage fluctuation (AV) across the storage module can be analyzed preferentially when two modules are in parallel mode and their ohmic resistance (Z) is known. The instantaneous current can then be easily calculated. by: i = The voltage variation is preferably determined from the voltage profile of the memory module is calculated immediately before and immediately after the state transition to parallel mode, preferably within 0.1 ms before and after the transition. Preferably, the voltage variation is also subjected to a function that can (substantially) compensate for the nonlinear effects of the voltage sensor.

[0058] The estimated current corresponds to the instantaneous load current (common-mode current) and the circulating current. The instantaneous (noisy) circulating current is estimated by subtracting the load current from the estimated current (instantaneous load current). Cir , noisy = i ~ oaa) and then passed through a low-pass filter to obtain a low-noise circular current.

[0059] The energy system or battery system according to the invention has similar or the same advantages as known smart batteries, which, however, require identical battery modules, i.e., preferably battery modules with (essentially) identical parameters or features. The advantages of the energy system according to the invention include high flexibility and wide scalability. The output quality of the energy system is particularly high, generally higher than in known energy systems with hard-wired batteries. A higher effective switching frequency is also achieved. Furthermore, the energy system according to the invention offers the possibility of sensorless operation and balancing with similar battery modules or energy modules by connecting them in a parallel mode.A further advantage is that components with the same or lower voltage (preferably less than, for example, 12 V, 24 V, 48 V, 60 V, 100 V, or 150 V) or current (preferably less than half or one-tenth of the load current) can be used to construct larger systems. The energy system according to the invention also has a similar or identical number of semiconductors and requires a similarly large chip area as known batteries.

[0060] In addition to the ability to use energy modules or battery modules with significantly different properties, the energy system or battery system offers the advantage of achieving a higher output bandwidth and optimized response times. The influence of inductances is also significantly reduced when voltage differences between different battery modules are similar.

[0061] By controlling the energy system with the control unit, the energy system's output control loop is decoupled from the energy transfer loop (internal loop). This enables active bidirectional energy transfer between energy modules or battery modules with different voltage levels. It is therefore not a requirement that the energy modules have the same voltage level or voltage levels. The decoupling also has no negative impact on the energy system's output voltage. Furthermore, the control can be easily implemented in gate drivers or in a modulation stage. It is possible to use both a centralized control system and a distributed control approach. The method according to the invention does not require optimization, look-up tables, and / or complex control systems. It is a simple control system in which the switching frequency remains constant.

[0062] The inventive method for controlling the different operating modes of an energy system comprises the following steps: generating a plurality of temporally offset carrier signals, for example, by means of a clock generator or a controller or control module; generating a reference signal, sometimes also called a modulation control signal, for example, by means of a generator or a controller or control module; and generating an offset signal, for example, by means of an energy generator or a controller or control module. A control signal is generated from the carrier signal, the reference signal, and / or the offset signal and transmitted to one of the switching units of the energy system for switching the switching unit.The switching unit is influenced in such a way and the switches in the switching unit are switched in such a way that the energy modules of the energy system are switched in a predetermined operating mode or switched from a first operating mode to a second operating mode.

[0063] The method according to the invention can also be implemented as software, wherein different measurement signals are processed and an output signal, the control signal, is delivered to a generator, which influences the switching units of the energy system via an output interface and switches them to a predetermined state (mode) resulting from the program sequence and the input data or the input signals.

[0064] The present invention also relates to a vehicle, for example a motor vehicle, an electric vehicle, a hybrid vehicle or automobile, a passenger car, a truck, electric truck, a boat, a watercraft, an aircraft, a motorcycle or bicycle. A vehicle is any vehicle that can retrieve energy from an energy storage device and convert it into a translational movement and can preferably be used to transport people and / or goods. The vehicle according to the invention has an energy system with several different energy modules and at least two switching units. It comprises a control unit that is designed and configured to switch the energy modules into different operating modes. The operating modes include a parallel mode, a series mode, a bypass mode, a boost mode and a hybrid mode.Hybrid mode represents a partial parallel mode that includes a mode between parallel and series, bypass, or boost, or a combination of parallel and series, boost, or bypass. Regardless of the vehicle, the energy system described above may preferably include the operating modes listed here, including parallel, series, bypass, boost, and hybrid.

[0065] The generators disclosed here, in particular the clock generator, the signal generator and the energy generator, can be controllers or control units, for example energy controllers, power controllers, etc. The controllers or control units can generate a signal that is suitable for controlling a switching unit or a switch or element of the switching unit or that can be amplified by means of an amplifier or generator or converted into a desired signal form or strength.

[0066] The invention is described and explained in more detail below using selected embodiments in conjunction with the accompanying drawings. They show:

[0067] Fig. 1 is a schematic diagram of the control unit according to the invention;

[0068] Fig. 2 a schematic diagram of an energy system or battery;

[0069] Fig. 3 shows a basic circuit of the energy system according to the invention with control unit;

[0070] Fig. 4a to c schematic diagrams for an asymmetric dual modulation for controlling a bidirectional energy transfer between two adjacent energy modules or within the energy system;

[0071] Fig. 5a to c show a schematic diagram of a symmetrical dual modulation for bidirectional energy transmission between two adjacent energy modules or within an energy system; Fig. 6a to c show a first embodiment of a 2-quadrant energy system with mutual inductance for heterogeneous energy modules, as well as the control unit and a switching table;

[0072] Fig. 7a to f an intelligent 4-quadrant energy system with mutual inductance for heterogeneous energy modules with control and switching table;

[0073] Fig. 8a, b a 4-quadrant energy system with mutual inductance for heterogeneous energy modules and split energy module as well as switching table;

[0074] Fig. 9a to e a simplified representation of an energy system with mutual inductance for heterogeneous energy modules with switching units with diodes;

[0075] Fig. 10a, b a 4-quadrant energy system with mutual inductance for heterogeneous energy modules with modified H-bridge; and

[0076] Fig. 11 a schematic diagram of an energy system with mutual inductances and mixed energy modules.

[0077] Figures 1 to 3 show the control unit 10 according to the invention, an energy storage system 20 and an energy system 30, respectively.

[0078] The control unit 10 is configured to switch an energy storage system or an energy system 30 into different operating modes. The control unit 10 comprises a clock generator 12 that generates a plurality of time-offset carrier signals. A signal generator 14 generates a reference signal, also referred to as a modulation control signal. An energy generator 16 of the control unit 10 generates an offset signal. The control unit 10 is designed and configured to generate a control signal based on at least the reference signal of the signal generator. The control signal is output to a switching unit of an energy system 30 or an energy storage system 20 via an output interface 18 of the control unit 10. The control signal enables the switching unit to be switched, so that energy modules of the energy system or energy storage system 20 are switched to a predetermined operating mode.The control signal can therefore preferably comprise several signal components or partial signals (hereinafter also referred to as control signal), so that several switching units or switches can be switched independently of one another.

[0079] Figure 2 shows an energy storage system 20 comprising two energy modules 22 and two switching units 24, which are preferably arranged between the two energy modules 22. The two switching units 24 are connected to one another by at least one inductance 26. The inductance 26 can be a parasitic inductance of a connection 28 between the two switching units 24. The parasitic inductance can preferably be increased by an inductance as a component, by adding magnetic material and / or by enlarging the loop between the energy modules. Preferably, an inductance 26 is connected as a component between each of the two switching units 24, which inductance includes a mutual inductance. Further connections are provided between the energy modules 22 and the switching units 24, wherein their parasitic inductance is included in the inductance 26 in the circuit diagram.An external current through the energy storage system 20, which is referred to as i. ou t, splits into the two connections 28 and flows through the two inductances 26 shown here.

[0080] Due to the mutual inductance that exists between the two switching units 24, a current flows through the two inductances 26. The current has two components that affect the external output current i ou t and a circulating current or circular current i Cjrsplit. While the output current is a common-mode current, the circular current is a differential-mode current. The mutual inductance is designed to have a low common-mode inductance and a high differential-mode inductance. The mutual inductance is preferably a factor of 10, very preferably a factor of 100, and most preferably a factor of 1000 greater than the common-mode inductance. The output current should therefore be distributed approximately evenly between the two inductances or the two connections.

[0081] While currents with the same sign (e.g., the output current) experience almost no inductance in the connections, currents with opposite signs (circular current, differential current) experience significant inductance. Since the output current is the main component of the current through the inductors or coils, it is preferably divided equally between the two inductors. This effectively neutralizes their magnetization. This makes it possible to use relatively small magnetic cores, which also do not saturate.

[0082] On the other hand, the current used and required for energy transfer between the energy modules 22, the circulating current, is limited by the large equivalent mutual inductance. However, since this current has much lower amplitudes than the output current, typically at least a factor of 10 lower, small magnetic cores with small dimensions are sufficient to enable energy transfer between the modules. For a circulating current that is at least 10 times smaller than the load current, the magnetic core is preferably 10 times, particularly preferably 100 times, smaller than conventional solutions suitable for energy transfer. Magnetic conductors around the electrical conductors, for example, with an outer edge length 10 mm, preferably 20 mm, larger than the conductor edge length in the corresponding direction (for busbars; for round arrangements, a correspondingly larger diameter).The length is preferably at least 10 mm, very preferably 20 mm, particularly preferably at least 1 / 3 of the conductor length.

[0083] The energy system 30 according to Figure 3 comprises, in addition to the energy modules 22, the switching units 24 and the inductors 26, as already shown in Figure 2, also the control unit 10 from Figure 1. The output current i ou t is determined only by the load of the energy system 30 and by the output voltage of the energy system 30. The circulating current i Cjr or circulating current is, however, influenced by the operating modes or connection states of the individual energy modules 22.

[0084] Preferably, two adjacent energy modules 22, as shown in Figures 2 and 3, can assume different operating modes within the energy system 30. The operating mode is understood to be the manner in which the two energy modules 22 are interconnected with their switching units 24. An operating mode (series mode) is a series connection in which the two energy modules 22 are connected in series. There is (practically) no energy transfer between the two energy modules 22; however, the amplitude of the output voltage increases. The effective inductance for the output current is preferably determined from the difference between the inductance 26 of the first connection minus the mutual inductance in parallel and the difference between the second inductance of the second line minus the mutual inductance.

[0085] In parallel mode, two adjacent power modules 22 are connected in parallel. In this mode, energy is only transferred from the power module with the higher voltage to the power module with the lower voltage. However, only negligible effects on the output voltage are observed on the output side. The same applies to a bypass mode, in which the output voltage is neither increased nor decreased.

[0086] To switch between the various operating modes, at least one control signal is output by means of the control unit 10, which switches the switching units 24. Preferably, a plurality of control signals are output. Particularly preferably, each of the switching units 24 comprises one or more switches, which can preferably be individually controlled by control signals from the control unit 10. To generate the control signals, for example, a comparison of several carrier signals with control references, such as a reference signal, can be carried out. An additional delay interval between the switching of one switching unit 24 and the other switching unit 24 can be caused by an offset signal, so that a state can be brought about in which an inductance of at least one of the energy modules 22 can be charged. Such a state is also referred to as charging mode. The energy is thus "temporarily parked."In the next step, the energy from the inductance can then be specifically discharged and transferred to another energy module.

[0087] Although the energy system 30 can assume different operating states or modes in which the energy modules are interconnected differently, the output behavior of the energy system 30 is preferably nearly identical. This makes it possible to control energy transfer between adjacent energy modules 22 entirely internally without affecting the output voltage of the energy system 30. Therefore, separate and largely decoupled control units 10 can be implemented.

[0088] A suitable control unit 10 can preferably operate adjacent power modules 22 even with a constant voltage difference between the two power modules 22 and still exchange power in both directions between the power modules. It may even be possible to transfer power from a power module with a lower voltage to a power module with a higher voltage.

[0089] Within the scope of the invention, it was recognized that phase-shifted carrier signals can be used for switching, as well as for controlling and generating switching pulses for modular, nested, or cascaded converters. Such interleaved carriers are one of the most frequently used modulation methods for controlling and generating converter switching pulses. This principle can, in principle, also be used in the energy system or control unit according to the invention. Uniformly phase-shifted carrier signals or temporally shifted carrier signals with a single reference signal do guarantee a uniform distribution of the transit times between the individual modules. However, they are merely suboptimal with regard to several balancing aspects.

[0090] Deviating from this, according to the invention, a clock generator 12 is used to generate several time-shifted carrier signals to control the switching units and generate the corresponding switching pulses or control signals. This signal is compared with a reference signal from a signal generator 14, which preferably takes place in a comparator 32.

[0091] The output current i out of the energy system 30 is preferably determined only by the output regulator responsible for regulating the load and / or the voltage, i.e., the signal generator 14 and its signal. The circular current (push-pull current) of the mutual inductance is preferably controlled by the energy generator 16 (also called an energy regulator) and its output signal. Figure 4a shows the time-shifted carrier signals 121 of the clock generator 12. The reference signal 141 of the signal generator 14 is shown, as is the offset signal 161 of the energy generator 16 of the control unit 10 according to the invention. For each energy module 22 to be controlled, different reference signals 141 and offset signals 161 can be generated, which can be both positive and negative. Preferably, the sum of the reference signal 141 and the offset signal 161 is neither greater nor less than the maximum or minimum value of the respective carrier signal 112.

[0092] While Figure 4a shows the corresponding signals in the control unit 10, Figure 4b shows a circuit diagram of the control unit 10, with which an asymmetric dual modulation for controlling a bidirectional energy transfer between two energy modules 22 is implemented. In a comparator 32a, the reference signal 141 is compared with the carrier signal 121. The output signal of the comparator 32a is fed to a switching logic 34, from which the corresponding control signals for a switching unit 24a are generated. In the second comparator 32b, the carrier signal 121 is compared with the sum formed from the reference signal 141 and the offset signal 161. The comparison signal is also fed to a switching logic, in which control signals for the switching unit 24b are generated.

[0093] The signal generator 14 used can preferably be any modern regulator, such as those used for smart batteries, to regulate the output voltage, current, or power. For example, the signal generator 14 can comprise a PI controller that minimizes the feedback error. Another more complex controller incorporated into the signal generator is also possible.

[0094] Figure 4c shows the temporal connection of the various operating modes of the energy system 30. PM denotes parallel mode, SM denotes series mode, and BM denotes boost mode, in which energy is transferred from one module to an inductor between two adjacent modules. Mo denotes the duration or relative duration of the series connection or series mode with respect to the switching time, which specifies the duration of the entire switching cycle cy. Mo is therefore the relative time within the switching cycle cy during which the reference signal is output.

[0095] Md is the relative time for the application of the offset signal 161, which can specify the proportion of boost mode or parallel mode times during the remaining interval within the switching cycle. For example, the time period Md x cycle time = (1 - Mo) x cycle time. For Md = 0, the steady-state circular current (push-pull current) is determined by the voltage difference between two adjacent power modules 22 relative to the equivalent impedance of the power system 30.

[0096] By masking out non-ideal conditions, energy transfer between two adjacent energy modules 22 can preferably be prevented if the average voltage across the two energy modules 22 is zero. This is the case if, preferably, the average voltage across the inductors and the mutual inductance during series mode is zero, or more preferably, the average voltage across the inductors during parallel mode is equal to the voltage differences between the two energy modules multiplied by the time the parallel mode is switched on, or more preferably, the average voltage across the inductors during boost mode corresponds to the magnitude of the respective voltage across one of the energy modules times the time the boost mode is applied. Essentially, the value Md corresponds to the ratio of boost time to cycle time orSwitching time corresponds to the switching time and the ratio of time for parallel mode to the switching time or cycle time is equal to (1 - Mo - Md). Without a voltage difference between the modules and a value of Md = 0, the energy system 30 with different energy modules 22 would behave similarly to a smart battery, which, however, requires identical energy modules.

[0097] Figure 4c shows that a relative time period for the series mode is determined by the reference signal 141, while the time period for which the boost mode is activated is determined by the offset signal 161. In asymmetric dual modulation, the boost mode follows the series mode. If no reference signal 141 and no offset signal 161 are present, the power system 30 is in parallel mode.

[0098] Figures 5a to 5c show a symmetrical dual modulation for controlling bidirectional energy transfer. In contrast to the embodiment according to Figures 4a to 4c (asymmetrical dual modulation), Figures 5a to 5c show an alternative in which bidirectional energy transfer control is implemented symmetrically. The general behavior of symmetrical dual modulation corresponds to that of asymmetrical dual modulation.

[0099] According to Figure 5b, the signals used for comparison in comparator 32 are formed by summing or subtracting the reference signal and the offset signal, with the switching duration of the offset signal being adjusted if necessary. The signals are described in Figure 5a as "141 + 161" and "141 - 161," respectively. Alternatively, it is possible to use different carrier signals for each of the two modulation signals (preferably reference signal, offset signal).

[0100] Figure 5c shows that a parallel mode is followed by a boost mode, which is then followed by a series mode. The series mode is followed by a boost mode, which in turn is followed by a parallel mode. The changed modulation signals can also change the series mode, potentially affecting the output voltage of the power system. However, the general behavior of this control concept is similar to that of asymmetric dual modulation.

[0101] The operating modes described above for energy modules preferably also occur in energy systems that are a battery system and whose energy modules are battery modules. As an alternative to pure battery systems, other types of energy storage and / or supply can be considered, wherein the additional operating modes can be used to control secondary functions. In energy systems 30 with mixed energy modules 22, for example in a battery PV system, it is possible to supply the load both via the PV module as an energy module and via a battery module. The energy generator 16 can operate the PV modules at maximum power, for example to charge exhausted batteries. In this case, the energy generator 16 comprises, for example, a control module that is a maximum power point tracking module.It is also possible to integrate the energy generator 16 as a constant voltage regulator in order to improve the quality of the output voltage.

[0102] It is also possible to provide an energy system that is a battery fuel cell system, in which both batteries and fuel cells can be used as the energy module 22, supplying the load via the power regulator. However, to reduce aging, the battery modules would preferentially supply the power peaks, while the energy generator would use the energy regulator as a power supply with constant or low dynamic output power, preferentially replenishing the energy of the discharged batteries during low-charge conditions or times. It is also possible for energy modules to be used as super / ultra / capacitors instead of and / or in parallel with battery modules to form the required power or energy curves of each module depending on the requirements.

[0103] Figures 6a to 6c relate to a preferred embodiment of an energy system 30 for heterogeneous energy modules or heterogeneous battery modules. Within the scope of the invention, heterogeneous energy modules or battery modules of an energy or battery system are modules that are or can be different in their features, characteristics, properties, or type. Heterogeneous battery modules are, for example, modules that are different battery types or are based on different chemical elements.

[0104] The energy system 30 according to Figure 6a has two energy modules 22 designed as battery modules 42 and two switching units 24 which comprise the switches S1 and S2 or S3 and S4.

[0105] Figure 6c shows a table with the most important operating modes depending on the gate signals S1 to S4 generated by the controller or control unit 10. A "1" means that the switch is closed, while a "0" symbolizes an open switch. This applies to all tables in the text that represent switching states.

[0106] By appropriately controlling switches S1 to S4 according to the control loop shown in Figure 6b, the energy system 30 can be switched to the various modes. It is also possible to transfer energy from the energy module 22 designated EM1 to the energy module 22 designated EM2 and vice versa. The energy modules 22 can be different. It is possible to control the energy transfer between the energy modules 22 through asymmetric (Figure 6b) or symmetric dual modulation by switching back and forth between the parallel mode and one of the boost modes without noticeable effects on the performance. The ratio between series mode and parallel mode or boost mode and their respective durations preferably determines the main performance of the energy system 30. The ratio between the durations for the parallel mode and the boost mode preferably determines the magnitude and direction of the circulating current.The switching frequency remains unaffected in all cases.

[0107] Figures 7a to 7f relate to a further embodiment of an energy system 30 according to the invention with two energy modules 22, which are designed as a battery module 42. The preferred energy system 30 is designed as a 4-quadrant energy system with mutual inductance and is suitable for heterogeneous energy modules 22 or heterogeneous battery modules 42, i.e., the modules differ in their type, design, chemical composition, and / or typical parameters. The switching unit 24 each comprises four switches S1 to S4 and S5 to S8, respectively.

[0108] In this embodiment, it is not necessary to transfer energy from a module 22 with a higher voltage to an energy module 22 with a lower voltage and to switch the energy system 30 to boot mode. Energy transfer can preferably take place in a boost mode and / or a parallel mode. To transfer energy from an energy module with a lower voltage to an energy module with a higher voltage, one of the possible boost modes and one of the possible parallel modes can be selected. Preferably, the energy system 30 is first switched to boost mode in order to charge the inductance between the adjacent energy modules 22. In a further step, the energy system 30 is switched to parallel mode in order to transfer the energy from the inductance, for example, to the energy module 22 with the lower energy, thus bringing about energy equalization.The corresponding configurations for switches S1 to S8 are shown in the table in Figure 7d.

[0109] The control unit 10 is shown in Figure 7b, along with the possible switching states at the outputs: SM = series mode, BM = boost mode, and PM = parallel mode. The topology provided here for the control unit 10 is again an asymmetric dual modulation for bidirectional control of the power transfer.

[0110] The entire switching cycle cy, as known from Figures 4c and 5c, is again divided between parallel mode, series mode, and boost mode to control the main output of the power system 30. The interval in which the power modules are not connected in series mode SM is divided between boost mode and parallel mode according to the amplitude of the voltages.

[0111] Alternatively, the topology of the control unit 10 according to Figure 7b can also be operated such that a parallel mode is present at the BM output and a bypass mode is implemented at the PM output, but no boost mode. The interval in which the energy modules are not connected in series mode SM is divided between the bypass mode and the parallel mode according to the amplitude of the voltages. In this way, it is possible to implement energy transfer between two energy modules 22 without providing a boost mode.

[0112] For a large voltage difference between the two energy modules 22, the time for the series mode SM is preferably determined by the reference signal 141 and its duration, while the time for the parallel mode PM is preferably determined by the offset signal 161 and its duration. The overall switching frequency of the energy system can increase slightly in this case. In this embodiment, it is only possible to transfer energy from the energy module 22 with the higher voltage to the energy module with the lower voltage. The offset signal 161 can only determine and influence the energy transfer rate.

[0113] Although Figure 7b shows an asymmetric dual modulation technique, a symmetric dual modulation can also be implemented accordingly. This embodiment has the advantage that, without a boost mode, the voltage difference of the mutual inductance is formed only by the voltage difference between the two adjacent power modules 22. Therefore, the size of the inductance can be designed smaller.

[0114] If the control unit 10 is operated according to Figure 7b without bypass mode, an additional interval or a delay can be introduced between the switching state of the switching unit 24a designed as a full bridge and the switching unit 24b also designed as a full bridge according to Figure 7a, whereby the switching frequency of the individual energy modules 22 or the switching units 24 remains unchanged.

[0115] The delay of the signal generator can be controlled, for example, by comparing the measured circulating current between two energy modules 22 with a reference circulating current, see Figure 7c. The offset signal 161 of the energy generator 16 can be identical for each of the adjacent energy modules 22, or it can be uniquely controlled. However, the operating principle and control would be the same in both cases. The controller implemented in the energy generator 16 can, for example, be a PI controller.

[0116] Possible switching states for the switches S1 to S8 of the topology of the control unit 10 from Figure 7b are shown as an example in Figure 7d.

[0117] Figure 7e shows a further embodiment of a control unit 10, in which a parallel generator 17 is additionally present, the signal of which is added to the sum of the reference signal 141 and the offset signal 161 and compared with the carrier signal 121. As shown in Figure 7e, it is possible to implement a control unit 10 that can switch between both a boost mode and a bypass mode. Such an implementation is particularly suitable if the operating interval for the boost mode is specified at the hardware level, or if the current load is to be reduced, or if the voltage difference between two adjacent power modules is too large. The power generator 16 and the parallel generator 17 ensure a balance between the boost mode and the parallel mode in order to control the power transfer between the two power modules 22.

[0118] Figure 7f shows an example of the variation of the circulating current (push-pull current of the inductance) over time. In an alternative embodiment, sigma-delta controllers and / or hysteresis controllers can be combined with the proposed dual modulation technique to switch back and forth between the operating modes of boost mode, parallel mode, and bypass mode. Within the switching cycle cy, the energy system 30 is initially in series mode, as can be set according to the control units 10 described above. This is followed by a boost mode until the current reaches an upper limit of the inductance 26 or an upper limit of a reference current. This is followed by a parallel mode until the current drops to a lower limit, which can be zero amperes, for example. This is followed by a bypass mode for the remainder of the switching cycle cy.

[0119] In this operating mode, the switching frequency of the modules increases slightly, but the rated current through the inductors can be limited.

[0120] If charge balancing functions or load balancing functions need to be created in an energy system 30 that affect the entire energy system 30 without impairing performance, an energy transfer function can preferably be used. For example, a controller as shown in Figure 7c can be used for this purpose, in which the measured current through an energy module 22 is compared as an input variable with the average current across all energy modules 22 of the energy system 30. Such a control can also be implemented in a distributed form at the energy module level, with each energy module 22 being supplied only with the average reference signal or its specific signal, which it must follow.

[0121] Similar controls can be used to balance energy, temperature, power, etc. Alternatively, it is also possible to introduce hierarchical structures for the control unit 10 in order to optimize and, if necessary, reduce energy transfer in the entire energy system 30.

[0122] Figures 8a and b relate to a 4-quadrant energy system 30 with mutual inductance for heterogeneous energy modules 22, wherein the energy modules 22 are preferably composed of split energy modules EM11, EM12, EM21, and EM22. Figure 8a shows a corresponding wiring of two energy modules 22 at each end of the inductance 26 and the corresponding switching units 24, which are composed of several switches.

[0123] This embodiment can be considered a more limited version of the embodiments described in Figure 7. A person skilled in the art can adapt and apply the control units 10 described in detail above to this embodiment of the energy system 30.

[0124] In a preferred embodiment, if one of the energy modules is the last module in the energy system 30, the half-bridge with the switches S7 and S8 can be removed.

[0125] In parallel operation, for example, energy is transferred from an energy module 22 with the higher voltage to the energy module 22 with the lower voltage. It is possible for the split energy modules on each side of the inductance 26 to have different voltage levels. In practice, however, it has been shown that, due to symmetry, largely similar energy modules on both sides of the inductance are preferable. Figure 8b shows the most important switching states of the switches S1 to S8 from Figure 8a for setting the different operating modes. Energy transfer options preferably arise from the combination of boost mode and parallel mode, in which energy is transferred from the energy modules (EM11) 22a, 42a and (EM21) 22b, 42b, as well as from the second combination of boost mode and parallel mode with energy transfer from the energy module (EM12) 22c, 42c and energy module (EM22) 22d, 42d.

[0126] Furthermore, energy transfer is possible in the two parallel modes, namely with a parallel connection between EM11 22a, 42a and EM22 22b, 42b, and in the second parallel mode with a parallel connection between EM12, 22c, 42c and EM22, 22d, 42d. Therefore, energy can be preferentially transferred from each of the four energy modules 22 or battery modules 42 to the other modules. During operation, the output current is preferably distributed evenly between the two mutual inductances 26. Switches S1 to S4 determine whether there is a positive, a negative, or no voltage step.

[0127] Switching between the two boost modes is a way to maintain a controlled energy transfer between the two energy modules EM11 22a, 42a and EM21 22b, 42b and the two lower energy modules EM12 22c, 42c and EM22 22d, 42d.

[0128] The two boost modes, in combination with the other parallel modes and the correct selection of the voltages of the energy modules 22 or battery modules 42, enable the transfer of energy from one energy module 22 or battery module 42 to another module in any direction. For example, a transfer of energy from the energy module EM11 22a, 42a to the energy module EM21 22b, 42b is possible if appropriate intervals of the first boost mode, the first parallel mode, the second boost mode, and finally the second parallel mode, preferably in exactly this order, are enabled. This ensures energy transfer. Similar patterns can be developed by those skilled in the art for other energy transfer directions.

[0129] Figure 9a shows the topology of an energy system 30 according to the invention with mutual inductance for heterogeneous energy modules 22 or heterogeneous battery modules 42, wherein two diodes are used in each of the bridge circuits of the divided energy modules 22. Such a topology with diodes and switches is shown in Figure 9a. A person skilled in the art can develop control patterns based on the preceding explanations. A preferred option is shown in Figure 9b as a switching table for the switches S2, S4, S6, S8 and the diodes D1, D3, D5, and D7.

[0130] Figure 9c shows a preferred energy system 30 according to the invention, in which four diodes are also used in the bridge circuits of the switching units. However, the diodes are positioned in the lower strings instead of the upper strings as in Figure 9a. A corresponding, preferred switching pattern for setting the different operating modes is shown in Figure 9d.

[0131] Figure 9e shows another embodiment of an energy system 30 with distributed energy modules 22 or distributed battery modules 42 and two full-bridge circuits, each comprising two switches and two diodes. In this embodiment of the energy system 30, a boost mode cannot be enabled. Nevertheless, with the correct design of the energy modules 22 or battery module 42, a one-way energy transfer using parallel modes is possible. A person skilled in the art can easily implement corresponding control patterns based on the preceding explanations.

[0132] Figure 10a shows an energy system 30 according to the invention, in which a 4-quadrant energy system with mutual inductance is used for heterogeneous energy modules 22. A modified H-bridge is used here. Similar to the previous embodiments, it is possible to exchange energy between the two energy modules 22 or battery modules 42 by combining the different parallel modes and boost modes. Figure 10b shows exemplary preferred switch positions required to adopt the individual modes.

[0133] If no energy exchange is required, only the series mode (with low inductance) and bypass mode operating modes can be used. In parallel modes, however, energy transfer occurs from a higher-voltage power module 22 to a lower-voltage power module. In combination with boost mode, energy transfer can be controlled in both directions without any noticeable impact on overall performance.

[0134] Figure 11 shows a schematic diagram of another alternative embodiment of an energy system 30, in which the switching units 24 are symbolically represented by a circuit. The energy modules 22 can be different and mixed energy storage devices. For example, batteries or battery modules, capacitors, capacity banks, and the like can also be used here. At the same time, an energy module 22 can also be replaced, for example, by a power supply such as a PV module or a fuel cell.

[0135] In combination with a PV system, it is possible to use the additional operating modes to operate the PV system at maximum power and / or in voltage regulation mode. The PV system supplies the load, and the other energy storage devices are charged or discharged to compensate for the difference between the power generated by the PV system and the power required by the load.

[0136] When using battery modules as energy modules, it is preferably possible to charge the energy modules both via the input / output terminal and via other energy sources, such as a PV system or fuel cell. Alternatively, it is possible to connect a fuel cell to the modules, with the energy modules 22, preferably in the form of battery modules 42 or capacitors, supplying the rapidly fluctuating power, and the fuel cell supplying the power at lower voltages, which leads to a lower load on the fuel cell.

[0137] It is also conceivable to use a mixture of PV system and / or fuel cell and battery module 42 and / or capacitor bank in an energy system 30.

[0138] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other embodiments and variations will become apparent to those skilled in the art upon use of the present invention and upon careful analysis of the drawings, the disclosure, and the following claims.

[0139] The energy modules or battery modules used are to be understood in a general sense. Even though the invention has been described based on the use of a battery module as the energy module and the energy system has been referred to as a battery system, this should not be understood as a restriction to batteries. A key point of the invention, however, is that the energy modules and / or battery modules do not have to be of the same type, as is necessary for previously known batteries. Rather, they can differ in relevant characteristics and features, such as voltage levels, aging times, cycle times, chemical composition, etc.

[0140] In the claims, the words "comprising" and "having" do not exclude the presence of additional elements or steps. The undefined article "a" or "an" does not exclude the presence of a plurality. A single element or unit may perform the functions of several of the units recited in the claims. An element, unit, interface, device, and system may be implemented partially or entirely in hardware and / or software.

[0141] For example, it is possible to implement the controls and control unit partially or entirely in software, whereby, when the software is executed on a computer, microcontroller, or similar electronic processor, output signals can be output, for example, a logical 1 or a logical 0. These output signals can be used to control and switch the switches S1 to S8 in the examples shown, as well as the switching units 24, in order to transfer the energy system into different operating modes. An amplifier or generator may be required to convert the processor's output signals into switching signals for the switching units or switches.

[0142] Of course, the described circuit logic can be implemented in both hardware and software. A combination of both is also possible.

[0143] The mere mention of some of the measures listed above in several different dependent claims should not be understood to mean that a combination of these measures cannot also be used advantageously. A computer program can be stored or distributed on a memory and / or non-volatile data carrier. A computer program can be distributed or executed together with hardware and / or as part of hardware. Reference signs in the claims are not to be understood as limiting.

Claims

Patent claims 1. A control unit for an energy system for controlling different operating modes of the energy system (30) having two energy modules (22) and at least two switching units (24), comprising a clock generator (12) for generating a plurality of time-offset carrier signals (121); a signal generator (14) for generating a reference signal (141); an energy generator (16) for generating an offset signal (161); and an output interface (18) for outputting a control signal for switching at least one of the switching units (24) of the energy system (30) such that the energy modules (22) are switched to a predetermined operating mode, wherein the control unit (10) is designed and configured to generate the control signal based on at least the offset signal (161) and the reference signal (141) of the signal generator (14).

2. Control unit according to claim 1, characterized in that the control unit (10) is designed and configured to switch the energy modules (22) of the energy system (30) into the operating modes bypass mode, series mode and parallel mode as well as into a hybrid mode which comprises a combination of parallel mode and series mode or bypass mode, wherein preferably the control unit (10) is designed and configured to switch the energy modules (22) of the energy system (30) into the desired operating modes despite different voltages in the individual energy modules (22).

3. Control unit according to one of the preceding claims, characterized in that the output interface (18) has two outputs to which the control signal is applied and output, wherein preferably a plurality of control signals are generated and each of the outputs outputs a different control signal and wherein particularly preferably one of the outputs is coupled to a switching unit (24) and another output is coupled to another switching unit (24).

4. Control unit according to one of the preceding claims, characterized in that the output interface (18) has at least three outputs, wherein the first output is configured to switch on a series mode of energy modules (22) of an energy system (30) and the second output is configured to switch on a parallel mode of energy modules (22) of an energy system (30) and the third output is configured to switch on a boost mode in which energy is transferred from one energy module (22) of the energy system (30) to another energy module (22) of the energy system (30) by a combination of boost mode and parallel mode.

5. Control unit according to one of the preceding claims, characterized in that the control signal is formed from the comparison of the carrier signal (121) with the sum of the offset signal (161) and the reference signal (141) or the control signal is formed from the comparison of the carrier signal (121) with the reference signal (141).

6. Control unit according to one of the preceding claims, characterized in that the control of the energy modules (22) is carried out with symmetrical or asymmetrical dual modulation of the energy modules (22).

7. Control unit according to one of the preceding claims, characterized in that for generating the offset signal (161) a circular current i flowing between the switching units (24) Cjr ,m and as controlled variable is used, wherein preferably an error function is minimized, particularly preferably based on the measured circular current icir.m and a reference current icir.ref- 8. Control unit according to one of the preceding claims, characterized in that the reference signal is based on an output voltage V measured across an energy module (22) ou t,m is generated, preferably by minimizing an error function, particularly preferably based on the measured output voltage V ou t,m as controlled variable and a reference voltage V ou t,ref.

9. Energy system with at least two energy modules (22), two switching units (24), two connections (28) connecting the switching units (24) and with an inductance (26) arranged between the energy modules (22), characterized in that the two energy modules are battery modules which are different and, in addition to a different voltage or voltage profile, have at least one further different parameter, wherein the parameter is from the group of discharge curve, power density, chemical composition, energy density, predetermined aging voltage, cyclic aging profile or different battery types.

10. Configurable energy system with two energy modules, two switching units (24), two connections (28) connecting the switching units (24) and with an inductance (26) arranged between the energy modules (22), comprising a control unit (10) for controlling different operating modes of the energy system (30), preferably a control unit according to one of claims 1 to 8, with a clock generator (12) for generating a plurality of time-shifted carrier signals (121); a signal generator (14) for generating a reference signal (141); an energy generator (16) for generating an offset signal (161); and an output interface (18) for outputting a control signal for switching at least one of the switching units (24) of the energy system (30), wherein the control signal is formed from the carrier signal (121), the reference signal (141), the offset signal (161) and / or a combination of the reference signal (141) and the offset signal (161); and the control signal is designed such that the two energy modules (22) are switched to a predetermined operating mode.

11. Energy system according to claim 10, characterized in that an operating mode comprises a hybrid mode comprising a combination of parallel mode and series mode or of parallel mode and bypass mode or of parallel mode and boost mode.

12. Energy system according to one of claims 10 to 11, characterized in that at least two of the energy modules (22) of the energy system (30) are different, wherein in addition to a different voltage profile or a different voltage, at least one further parameter for the energy modules (22) is different and the parameter is from the group of power density, chemical composition, energy density, predetermined aging voltage, cyclic aging profile or different battery types.

13. Energy system according to one of claims 10 to 12, characterized in that the switching units (24) each comprise two switches (S1, S2), which are preferably connected in series, wherein particularly preferably one switch is connected in parallel to an energy module (22), further Preferably a switch is connected between the two common-mode inductances of the lines.

14. Energy system according to one of claims 10 to 13, characterized in that the output interface (18) of the control unit (10) has a plurality of output ports, wherein preferably one output port each controls and switches a switch of the switching units (24).

15. Energy system according to one of claims 10 to 14, characterized in that the switches of the switching units (24) are circuits which can assume at least a low-resistance state with an impedance of less than 1 ohm and a high-resistance state with an impedance of more than one megaohm, wherein the switches are preferably transistors, very preferably FET transistors, MOSFETs, IGBTs, GANs or thyristors, wherein the switching units (24) particularly preferably comprise at least one diode.

16. Energy system according to one of the preceding claims 10 to 15, characterized in that the energy modules (22) are connected in two-quadrant mode, preferably the energy system (30) comprises at least 4 energy modules (22) and the energy modules are connected in four-quadrant mode.

17. Energy system according to one of the preceding claims 10 to 16, characterized in that the energy modules (22) are different in that they have different parameters, have different voltage levels, are different battery types and / or comprise different chemical elements.

18. Energy system according to one of the preceding claims 10 to 17, characterized in that one of the energy modules (22) comprises a battery module (42) with a rechargeable storage element, a non-rechargeable battery, a PV module, a fuel cell, a super cap or a capacity bank.

19. A method for controlling different operating modes of an energy system (30) with two energy modules (22) and two switching units (24) coupled to the energy modules (22), comprising the following steps: Generating a plurality of time-shifted carrier signals (121), preferably by means of a clock generator (12); Generating a reference signal (141), preferably by means of a signal generator (14); Generating an offset signal (161), preferably by means of an energy generator (16); Generating a control signal from the carrier signal (121), the reference signal (141) and / or the offset signal (161); and Outputting the control signal to one of the switching units (24) of the energy system (30) for switching the switching unit (24) such that the energy modules (22) of the energy system (30) are switched to a predetermined operating mode, wherein an operating mode comprises a hybrid mode comprising a combination of parallel mode and series mode, boost mode or bypass mode.

20. A computer program product comprising program code for performing the steps of the method according to claim 19 when the program code is executed on a computer.

21. Vehicle with an energy system with a plurality of different energy modules (22) and at least two switching units (24), and with a control unit which is designed and configured to switch the energy modules into different operating modes, wherein one of the operating modes comprises a hybrid mode with a combination of parallel mode and series mode or bypass mode.

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