DE102019212175A1 - Electronic device and method of operating an electronic device - Google Patents

Abstract

The invention relates to a method for operating an electronic device (1), the electronic device (1) having a plurality of dual-active-bridge converters (21-2N) connected in parallel, the dual-active-bridge converters (21 -2N) can be controlled with at least partially differing control parameters, the control parameters being selected in such a way that dead time ranges of the dual-active-bridge converters (21-2N) differ at least partially from one another in order to improve the controllability of the electronic device.

Description

The present invention relates to an electronic device and a method for operating an electronic device. The electronic device can in particular be a converter.

State of the art

Dual-active bridge converters are bidirectional DC / DC converters with two semiconductor full bridges, which, due to their compactness, are advantageous over two separate converters in applications with limited installation space. Further advantages are galvanic potential separation and good parallelization. A detection method using dual active bridge converters is known from US Pat EP 3 285 382 A1 known.

The parameters dependent on the operating point are influenced by dead time effects. A more detailed discussion of this effect can be found in Song et al., "Dead-time effect analysis of dual active bridge DC-DC converter with dual-phase-shift control", Proceedings of the 2017 Chinese Automation Congress (CAC), Jinan, China, October 20-22, 2017; pp. 6545-6550 .

Dead-time effects influence the controllability of the system. A dead time is to be understood here as the time span between a signal change at the system input and a signal response at the system output of a controlled system. With significant dead times, it can happen that an increase in the manipulated variable does not have the desired effect on the output variable. Such dead times occur for dual-active bridge converters in the transition area between hard-switching and soft-switching operation, so that this transition area can be described as a dead time area. This can lead to stagnation of the manipulated variable in the controlled system or self-amplification of the manipulated variable, depending on the operating point and the transition area. If several dual-active bridge converters are operated in parallel, this undesirable effect can be amplified. There is therefore a need to improve the operation of dual active bridge converters connected in parallel.

Disclosure of the invention

The invention provides a method for operating an electronic device having the features of claim 1 and an electronic device having the features of claim 9.

Preferred embodiments are the subject of the respective subclaims.

According to the first aspect, the invention accordingly relates to a method for operating an electronic device which has a plurality of dual-active-bridge converters connected in parallel. The dual-active bridge converters are controlled with at least partially different control parameters. The control parameters are selected in such a way that dead time ranges of the dual active bridge converters differ from one another at least partially.

According to a second aspect, the invention accordingly relates to an electronic device with a multiplicity of parallel-connected dual-active-bridge converters and a control device for controlling the parallel-connected dual-active-bridge converters. The control device controls the dual-active bridge converter with control parameters which at least partially differ from one another. The control device selects the control parameters in such a way that dead time ranges of the dual-active bridge converters differ from one another at least partially.

Advantages of the invention

One idea on which the invention is based is to prevent all dual-active bridge converters from being in a dead time range at the same time, which would result in a strong influence on the operating point-dependent parameters. Different activation of the various dual-active bridge converters ensures that at most a subset of the dual-active bridge converters is in the dead time range at the same time. This prevents or at least reduces the dead-time effects from adding up. The influence of dead-time effects on the control behavior in the case of controlled dual-active-bridge converters connected in parallel is reduced. The controllability of the dual active bridge converter is improved.

Control parameters are understood to mean variables which are used in the control method or which influence it. Control parameters include, in particular, reference variables, setpoints, manipulated variables and manipulated variables.

According to one embodiment of the method, the control parameters which at least partially differ from one another comprise setpoint values for output currents of the dual-active bridge converters. The output currents are thus divided asymmetrically. The dead time ranges depend on the output currents, so that when the output currents selected are sufficiently different, dead time ranges that differ from one another are achieved.

According to a further embodiment of the method, the setpoint values for the output currents of the dual-active bridge converters differ at least partially from one another in the entire operating range of the dual-active bridge converters.

According to a further embodiment of the method, the setpoints for the output currents of the dual-active bridge converters differ at least partially from one another in the respective dead time ranges, ie in the transition regions between hard-switching operation and soft-switching operation of the dual-active-bridge converters . With this operating strategy, an effect on the electromagnetic and thermal design of the individual dual-active bridge converters is avoided or at least reduced.

According to a further embodiment of the method, the at least partially differing control parameters include phase angles for controlling the dual-active bridge converter. The phase angles (also called control angle or control angle or “power angle”) are set by a control device in order to regulate to a specified setpoint for the output current of the dual-active bridge converter. The operating strategy, according to which different phase angles are set, makes use of the fact that different combinations of phase angles can be selected for a given setpoint value for the output current of a dual-active bridge converter. The choice of the phase angle influences the dead time range, so that by choosing different combinations of the phase angles for different dual active bridge converters for identical nominal values for the output current, it can be achieved that dead time ranges of the dual active bridge converters at least partially differ from each other.

According to one embodiment of the method, the phase angles for driving the dual-active-bridge converters include a time shift between voltage pulses on a primary side and a secondary side of the dual-active-bridge converters.

According to one embodiment of the invention, the phase angles of the dual-active bridge converters are set using at least partially different look-up tables. The settings of the phase angles are thus stored for predetermined output currents of the dual-active bridge converter in a large number of at least partially different look-up tables, which are accessed by a control device for controlling the dual-active bridge converter. In particular, the look-up tables can be stored in a memory of the control device.

According to a preferred development of the electronic device, the control parameters, which at least partially differ from one another, comprise setpoint values for output currents of the dual-active bridge converters and / or phase angles for controlling the dual-active bridge converters.

Figure list

• 1 ein schematisches Blockdiagramm eines elektronischen Geräts gemäß einer Ausführungsform der Erfindung;
• 2 ein schematisches Blockdiagramm von parallelgeschalteten Dual-Active-Bridge-Wandlern des elektronischen Geräts;
• 3 ein schematisches Blockdiagramm eines einzelnen Dual-Active-Bridge-Wandlers;
• 4 ein Schaltbild eines Dual-Active-Bridge-Wandlers;
• 5 schematische Spannungsverläufe beim Betreiben eines elektronischen Geräts;
• 6 schematische Zeitabhängigkeiten eines Phasenwinkels und Ausgangsstroms bei sich verändernder Last;
• 7 schematische Zeitabhängigkeiten des Ausgangsstroms bei sich verändernder Last bei asymmetrischer Aufteilung der Sollwerte für die Ausgangsströme der Dual-Active-Bridge-Wandler im gesamten Betriebsbereich;
• 8 schematische Zeitabhängigkeiten des Ausgangsstroms bei sich verändernder Last bei asymmetrischer Aufteilung der Sollwerte für die Ausgangsströme der Dual-Active-Bridge-Wandler im Totzeitbereich; und
• 9 ein Flussdiagramm eines Verfahrens zum Betreiben eines elektronischen Geräts gemäß einer Ausführungsform der Erfindung.

Show it:

• 1 a schematic block diagram of an electronic device according to an embodiment of the invention;
• 2 a schematic block diagram of parallel-connected dual active bridge converters of the electronic device;
• 3 a schematic block diagram of a single dual active bridge converter;
• 4th a circuit diagram of a dual active bridge converter;
• 5 schematic voltage curves when operating an electronic device;
• 6th schematic time dependencies of a phase angle and output current with a changing load;
• 7th Schematic time dependencies of the output current with changing load with asymmetrical distribution of the setpoints for the output currents of the dual-active-bridge converter in the entire operating range;
• 8th Schematic time dependencies of the output current with changing load with asymmetrical distribution of the setpoint values for the output currents of the dual-active-bridge converter in the dead time range; and
• 9 a flow diagram of a method for operating an electronic device according to an embodiment of the invention.

Identical or functionally identical elements and devices are provided with the same reference symbols in all figures.

Description of the exemplary embodiments

1 Figure 3 shows a schematic block diagram of an electronic device 1 , in particular a converter or converter, with a large number of parallel-connected dual-active-bridge converters 21st to 2N , where N is any natural number greater than 1.

The electronic device 1 includes a control device 3 , which is the dual active bridge converter 21st to 2N regulates. The control device 3 can be software and / or hardware components include CPUs (central processing unit), GPUs (graphics processing unit), microcontrollers, integrated circuits, ASICs (application-specific integrated circuits), FPGAs (field programmable gate array) or the like. The direction of calculation 12 can further comprise at least one volatile or non-volatile memory in which control parameters are stored, for example look-up tables in which the phase angles for controlling the dual-active bridge converter 21st to 2N for specified setpoints of the output currents of the dual active bridge converter 21st to 2N are filed.

The control device 3 regulates the dual-active bridge converter to specific setpoint values for output currents, the control parameters being selected in such a way that the dead time ranges of the dual-active bridge converter are 21st to 2N at least partially differ from one another. In particular, a setpoint value for an output current of the entire electronic device can be used 1 be specified, and the control device 3 assumes an asymmetrical distribution of the specified output current to the individual dual active bridge converters 21st to 2N in front.

wobei N die Gesamtanzahl der Dual-Active-Bridge-Wandler 21 bis 2N bezeichnet.The control device 3 thus divides the specified total output current I _{s, DC, tot} into partial currents: $${\mathrm{I.}}_{s,\mathrm{D.}\mathrm{C.},Ges}={\displaystyle \sum _{n=1}^N{\mathrm{I.}}_{s,\mathrm{D.}\mathrm{C.},n}}$$

where N is the total number of dual active bridge converters 21st to 2N designated.

The values of the output currents I _{s, DC, n of} the dual active bridge converter 21st to 2N are at least not all identical. Preferably, all values of the output currents I _{s, DC, n} differ from one another. The values can be found in a look-up table in a memory of the control device 3 be filed.

Additionally or alternatively, the control device 3 the phase angle for controlling the dual active bridge converter 21st to 2N for the different dual active bridge converters 21st to 2N select at least partially different.

2 FIG. 8 shows a schematic block diagram of dual active bridge converters connected in parallel 21st to 2N of the electronic device 1 .

In 3 Figure 3 is a schematic block diagram of a single dual active bridge converter 21st illustrated. All dual active bridge converters 21st to 2N can be constructed identically. The dual active bridge converter 21st to 2N however, they can also differ in their electronic configuration. The dual active bridge converter 21st comprises a first bridge on the primary side 211 which have a high frequency transformer area 212 with a second, secondary bridge 213 is coupled.

4th shows a circuit diagram of the dual active bridge converter 21st . The first bridge on the primary side 211 includes first to fourth switches S _{p, 1} to S _{p, 4} and the second, secondary bridge 213 includes fifth to eighth switches S _{s, 1} to S _{s, 4} which include semiconductor components such as MOSFETs. The transformer area 212 comprises a first primary-side inductor L _σ1 , a second primary-side inductor L _h as well as an inductance on the secondary side L _σ2 . There is an input voltage on the primary side V _{p, DC} provided by the bridges 211 , 213 and the transformer area 212 is converted so that an output voltage on the secondary side V _{s, DC} provided.

5 shows schematic voltage curves when operating an electronic device. As in the upper part of the 5 As shown, the primary-side voltage V _{p, DC is provided in the form of a} pulse with voltage values V _p or -V _p , with a time duration of a pulse being predetermined by a first phase angle α. On the secondary side, voltage pulses with voltage values V _s or -V _{s result} , the duration of the pulses being predetermined by a second phase angle β. A third phase angle δ is given by a time shift between central points of the voltage pulses on the primary side and the secondary side.

The output current I _{s, DC} is a function of the phase angle, I _{s, DC} (α, β, δ). The control device 3 selects the phase angles α _n , β _n , δ _n , n = 1 ... N for the individual dual active bridge converters 21st to 2N in such a way that the respectively specified output current I _{s, DC} results. $${\mathrm{I.}}_{s,\mathrm{D.}\mathrm{C.}}\left({\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="DE102019212175A1\_0005.png,DE102019212175A1\_0007.png"\; state="\{\{state\}\}">\alpha </figure-callout>}}_1,{\mathrm{<figure-callout\; id="1"\; label="\beta "\; filenames="DE102019212175A1\_0005.png,DE102019212175A1\_0007.png"\; state="\{\{state\}\}">\beta </figure-callout>}}_1,{\delta }_1\right)={\mathrm{I.}}_{s,\mathrm{D.}\mathrm{C.}}\left({\mathrm{<figure-callout\; id="2"\; label="\alpha "\; filenames="DE102019212175A1\_0005.png,DE102019212175A1\_0007.png"\; state="\{\{state\}\}">\alpha </figure-callout>}}_2,{\mathrm{<figure-callout\; id="2"\; label="\beta "\; filenames="DE102019212175A1\_0005.png,DE102019212175A1\_0007.png"\; state="\{\{state\}\}">\beta </figure-callout>}}_2,{\delta }_2\right)=\cdots ={\mathrm{I.}}_{s,\mathrm{D.}\mathrm{C.}}\left({\mathrm{<figure-callout\; id="3"\; label="\alpha "\; filenames="DE102019212175A1\_0003.png,DE102019212175A1\_0005.png"\; state="\{\{state\}\}">\alpha </figure-callout>}}_3,{\beta }_N,{\delta }_N\right).$$

Different phase angles α _n , β _n , δ _n can result in the same output current I _{s, DC} . For at least partially different combinations of phase angles α _n , β _n , δ _n for different dual active bridge converters 21st to 2N it can be achieved that the dead time ranges of the dual active bridge converter 21st to 2N at least partially differ from one another. While in the above equation the output currents I _{s, DC of} the individual dual-active-bridge converters 21st to 2N If all are chosen the same, this can also be applied to the electronic device at least for certain ones 1 differentiate between loads.

6th shows a schematic time dependency of the third phase angle 8th and the output current I _{s, DC} on the secondary side with a linearly increasing load on the electronic device 1 . In a hard-switching area A, the actually measured third phase angle δ increases linearly and differs from a predefined profile for the third phase angle δ _r only by a fixed offset, which has no effect on the regulation. In a soft-switching area C, the third phase angle δ actually measured corresponds to the predetermined profile for the third phase angle δ _r . The third phase angle δ actually measured increases up to a maximum value | δ | _max . An intermediate area or transition area B is problematic for the regulation, since in this dead time area the edge has no clear relationship to the control point. In the dead time range B, the value is the third phase angle 8th equal to a fixed value δ _ZVS , which is used to control the dual-active bridge converter 21st to 2N used zero-voltage switching procedure is specified. The output current I _{s, DC of} the dual-active bridge converter increases analogously 21st to 2N in the first and third area A, C, while it remains essentially constant in the dead time area B. The output current I _{s, DC} increases up to a maximum value | I _{s, Dc} | max on.

The phase angles α, β, δ and / or the output currents I _{s, DC of} the dual-active bridge converter 21st to 2N are controlled by the control device 3 regulated in such a way that the dead time ranges B of the dual-active bridge converter 21st to 2N at least not for all dual-active bridge converters 21st to 2N completely overlap. In particular, the dead time ranges can only partially overlap or only for subsets of the dual-active bridge converters 21st to 2N overlap. All dead time ranges are preferably the dual-active bridge converter 21st to 2N separated.

7th shows the time dependencies of the output current I _{s, DC} with a changing load with asymmetrical distribution of the setpoints for the output currents of two dual-active bridge converters 21st to 2N . A dead time range B _{1 of} the first dual active bridge converter 21st to 2N is disjoint to a dead time range B _{2 of} the second dual-active bridge converter 21st to 2N , therefore takes place at an earlier point in time. The control device 3 controls the dual active bridge converter here 21st to 2N in such a way that the setpoints for the output currents I _{s, DC, 1} , I _{s, DC, 2 of} the dual-active bridge converter 21st to 2N differentiate throughout the operating range.

8th likewise shows schematic time dependencies of the output currents I _{s, DC, 1} , I _{s, DC, 2} with changing load with asymmetrical distribution of the setpoint values for the output currents I _{s, DC of} two dual-active bridge converters 21st to 2N . In this case, however, the setpoint values for the output currents are essentially only within the dead time ranges B1 , B2 differently chosen. Outside of this, the setpoints for the output currents I _{s, DC are} identical.

9 FIG. 10 shows a flow diagram of a method for operating an electronic device 1 . The electronic device 1 includes a large number of dual active bridge converters connected in parallel 21st to 2N as well as a control device 3 for controlling the dual active bridge converter 21st to 2N .

In a first process step S1 become control parameters for controlling the dual active bridge converter 21st to 2N certainly. In particular, setpoint values for the output currents I _{s, DC of} the individual dual-active bridge converters can be used 21st to 2N can be specified. The setpoint values of the output currents I _{s, DC} can be derived from the on the electronic device 1 depend on the applied load, ie have a functional dependency. The setpoints for the output currents I _{s, DC of} different dual-active bridge converters 21st to 2N can differ at least partially, ie in particular for certain loads. Phase angles α, β, δ can also be used to control the dual-active bridge converter 21st to 2N can be specified. The phase angles α, β, δ can be specified using look-up tables. The phase angles α, β, δ of different dual-active bridge converters 21st to 2N can differ at least partially for given setpoint values of the output currents I _{s, DC} .

In a second process step S2 regulates the control device 3 the dual active bridge converter 21st to 2N using the specified control parameters.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 3285382 A1 [0002]

Non-patent literature cited

• Song et al., "Dead-time effect analysis of dual active bridge DC-DC converter with dual-phase-shift control", Proceedings of the 2017 Chinese Automation Congress (CAC), Jinan, China, October 20-22, 2017; pp. 6545-6550 [0003]

Claims (10)

Method for operating an electronic device (1), wherein the electronic device (1) has a plurality of dual-active-bridge converters (21-2N) connected in parallel, the dual-active-bridge converters (21-2N) having at least partially differing control parameters are controlled, the control parameters being selected in such a way that dead time ranges of the dual-active bridge converters (21-2N) differ from each other at least partially. Procedure according to Claim 1 , wherein the at least partially differing control parameters include setpoint values for output currents (I _{s, DC} ) of the dual active bridge converters (21-2N). Procedure according to Claim 2 , the setpoint values for the output currents (I _{s, DC} ) of the dual-active-bridge converters (21-2N) differing at least partially from one another in an entire operating range of the dual-active-bridge converters (21-2N). Procedure according to Claim 2 , the setpoint values for the output currents (I _{s, DC} ) of the dual-active bridge converters (21-2N) differing at least partially from one another in the dead time ranges of the dual-active bridge converters (21-2N). Method according to one of the preceding claims, wherein the at least partially differing control parameters include phase angles (α, β, 8) for driving the dual-active bridge converter (21-2N). Procedure according to Claim 5 , wherein the phase angles (α, β, δ) for controlling the dual-active-bridge-converter (21-2N) have a time shift (δ) between voltage pulses on a primary side and a secondary side of the dual-active-bridge-converter (21 -2N). Procedure according to Claim 5 or 6th , the phase angles (α, β, δ) of the dual-active bridge converter (21-2N) being set using at least partially different look-up tables. Method according to one of the preceding claims, wherein the control parameters are selected such that when the load on the electronic device (1) rises or falls, at most one or some of the dual-active bridge converters (21-2N) are in a dead time range is located. Electronic device (1), with a plurality of dual active bridge converters (21-2N) connected in parallel; and a control device (3) which is designed to control the dual active bridge converter (21-2N) with at least partially different control parameters, the control device (3) being designed to select the control parameters in such a way that that dead time ranges of the dual active bridge converters (21-2N) differ at least partially from one another. Electronic device (1) according to Claim 9 , the at least partially differing control parameters setpoint values for output currents (I _{s, DC} ) of the dual-active bridge converters (21-2N) and / or phase angles (α, β, δ) for controlling the dual-active bridge -Converters (21-2N) include.

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