Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/3353—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
  • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/0064—Magnetic structures combining different functions, e.g. storage, filtering or transformation
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/32—Means for protecting converters other than automatic disconnection
  • H02M1/322—Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
  • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
  • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
  • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
  • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
  • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
  • H02M3/33584—Bidirectional converters
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/337—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only in push-pull configuration
  • H02M3/3376—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only in push-pull configuration with automatic control of output voltage or current
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
  • H02M1/007—Plural converter units in cascade
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/0083—Converters characterised by their input or output configuration
  • H02M1/0093—Converters characterised by their input or output configuration wherein the output is created by adding a regulated voltage to or subtracting it from an unregulated input
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of dc power input into dc power output
  • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
  • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
  • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
  • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
  • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
  • H02M3/33573—Full-bridge at primary side of an isolation transformer

Definitions

• the present invention relates to a DC voltage converter.
• the present invention also relates to a method for controlling a DC voltage converter.
• DC converters are used in numerous areas. For example, electrical energy can be transmitted between a high-voltage network and a low-voltage network of an electric vehicle by means of a DC voltage converter.
• a DC voltage applied to an input connection of a DC voltage converter can be converted into a further DC voltage by means of the DC voltage converter, wherein the level of the electrical voltage at the input can be different from the level of the electrical voltage at the output of the DC voltage converter.
• phase-shifted full bridge topologies are known, for example.
• Such DC voltage converters comprise a transformer with a fixed transformation ratio.
• a variable setting of the output voltage is possible by means of an adjustable phase shift.
• the limits of the voltage ratio between input voltage and output voltage are limited, among other things, by the transformation ratio of a transformer in the DC voltage converter.
• the document DE 102016200 662 A1 describes a bidirectional DC voltage converter for transmitting electrical energy between a high-voltage network and a low-voltage network of an electric vehicle. By operating the DC voltage converter in the reverse direction, an intermediate circuit capacitor on the primary side of the DC voltage converter can be charged by the energy on the secondary side of the DC voltage converter.
• the present invention discloses a DC / DC converter and a method for operating a DC / DC converter having the features of the independent claims. Further embodiments are the subject of the dependent claims.
• a DC voltage converter with a first transformer, a first full bridge circuit, a second full bridge circuit and a second transformer.
• the first full bridge circuit is arranged electrically between a first connection of the DC voltage converter and a primary side of the first transformer.
• the second full bridge circuit is arranged electrically between a second connection of the DC voltage converter and a secondary side of the first transformer.
• a primary side of the second transformer is electrically arranged between the second full bridge circuit and a first connection element of the second connection of the DC voltage converter.
• a series circuit comprising the secondary side of the transformer, a first switching element and a first diode is also provided. This series circuit is electrically arranged between the first connection element of the second connection of the DC voltage converter and a second connection element of the second connection of the DC voltage converter.
• the first diode is in this case between the first connection element and the second connection element of the second connection of the DC voltage converter Arranged forward direction.
• an anode of the first diode points in the direction of the connection element with the positive polarity
• a cathode of the diode points in the direction of the connection element of the second connection with the negative polarity.
• a method for controlling a phase-shifted full bridge DC voltage converter with a step for charging a secondary side of a transformer, the transformer being arranged as a series inductance on the output side of the DC voltage converter.
• the method further comprises a step of discharging the electrical energy stored in the secondary side of the transformer via the primary side of the transformer.
• the present invention is based on the knowledge that the voltage range in which DC voltage converters, in particular DC voltage converters with a phase-shifted full bridge topology, generally only allow energy to be transmitted within a limited voltage range.
• This voltage range is limited, especially in the case of phase-shifted full bridge DC voltage converters, by the transformation ratio of the transformer between the primary side and the secondary side.
• the voltage on the primary side must be greater than the product of the transmission ratio N and the voltage on the secondary side.
• the topology according to the invention also enables energy to be transferred from the primary side to the secondary side, when the input voltage on the primary side is less than the above limit from the product of the transformation ratio and the secondary voltage.
• a transformer is provided instead of a simple series inductance on the secondary side.
• the primary side of the additional transformer can be connected between the secondary-side full bridge and an output connection of the DC voltage converter.
• the secondary side of the additional transformer together with a switching element and a diode arranged in the forward direction, forms a series circuit between the positive and negative connection of the secondary side of the DC voltage converter.
• the secondary side of the additional transformer can be charged by closing the switching element. By opening the switching element, the energy is transferred from the secondary side of the additional transformer to the primary side and enables energy to be transferred through the DC converter from the primary side to the secondary side, even if the electrical voltage on the primary side falls below the above-mentioned limitation.
• a second diode is arranged in parallel with the first switching element.
• the second diode is in particular arranged in antiparallel to the first diode.
• the cathode of the second diode points in the direction of the positive connection element of the second connection of the DC voltage converter.
• the second diode can be a so-called body diode of the first switching element.
• a second switching element is arranged parallel to the second diode.
• the functionality of the DC voltage converter can be increased even further.
• an energy flow in the reverse direction that is to say from the secondary side to the primary side of the DC voltage converter, can also be realized.
• the first connection of the DC voltage converter is designed to be electrically coupled to a first voltage source
• the second connection of the DC voltage converter is designed to be electrically coupled to a second voltage source.
• the electrical voltage of the first voltage source that is to say at the first input connection
• the first connection of the DC voltage converter can be coupled to a high-voltage network, such as the high-voltage network of an electric vehicle.
• the second connection of the DC voltage converter can be coupled, for example, to a low-voltage network, in particular a low-voltage network of an electric vehicle.
• the DC voltage converter is designed to transfer electrical energy from the first connection of the DC voltage converter in the direction of the second connection of the To transmit DC voltage converter.
• the DC voltage converter can also be designed to transfer electrical energy from the first connection to the second connection if the electrical voltage at the first connection of the DC voltage converter is less than the product of a transmission ratio of the first transformer and the electrical voltage at the second connection of the DC voltage converter .
• the first connection of the DC voltage converter is designed to be coupled to an intermediate circuit capacitor.
• the DC converter can be designed to discharge the intermediate circuit capacitor.
• the DC voltage converter can be designed to discharge the intermediate circuit capacitor below a predetermined electrical voltage threshold. In this way, the intermediate circuit capacitor can be discharged to a safe and harmless voltage level. Additional discharge circuits can be omitted.
• the intermediate circuit capacitor can be discharged here in particular to an electrical voltage which is smaller than the product of the transformation ratio of the first transformer and the voltage at the second connection of the DC voltage converter.
• the DC voltage converter can be designed to supply a load on the secondary side of the DC voltage converter (1) with the energy on the primary side, even if the voltage on the primary side is less than a predetermined minimum voltage.
• the predetermined minimum voltage is specified here by a transformation ratio of the transformer.
• the minimum voltage can result from the product of the electrical voltage on the secondary side and the transformation ratio of the transformer.
• the second full bridge circuit comprises two half bridges, each with two switching elements.
• the first full bridge circuit can also have two half bridges, each with two switching elements include.
• the DC voltage converter can be designed to control the switching elements of the first full-bridge circuit, the second full-bridge circuit and the first and optionally also the second switching element.
• the switching elements can be controlled, for example, by means of a suitable control device.
• the DC voltage converter in particular the control device of the DC voltage converter, can be designed to close the first switching element and to open the switching elements of the first full-bridge circuit in a first switching interval.
• the first switching element can be opened in a second switching interval and two switching elements can be closed in each case in a diagonal path of the first full-bridge circuit.
• the secondary side of the second transformer can be charged during the first switching interval.
• the electrical energy can then be transferred from the secondary side to the primary side of the second transformer. In this way, energy can be transferred from the primary side of the DC / DC converter to the secondary side of the DC / DC converter even if the electrical voltage on the primary side of the DC / DC converter falls below the product of the transmission ratio and voltage on the secondary side.
• the DC voltage converter in particular the control device of the DC voltage converter, can be designed to alternately open and close the switching elements of different diagonal paths in the first full bridge circuit in two successive second switching intervals. In this way, the DC voltage converter and the switching elements in the DC voltage converter can be controlled symmetrically.
• Fig. 2 a schematic representation of a time diagram for the
• FIG. 3 a schematic representation of a flowchart on the basis of a method for operating a DC voltage converter according to an embodiment.
• FIG. 1 shows a schematic representation of a basic circuit diagram on the basis of a DC voltage converter 1 according to an embodiment.
• the DC voltage converter 1 comprises, for example, a first connection Al with a first connection element Al-1 and a second connection element Al-2.
• the DC voltage converter 1 can be electrically coupled, for example, to a voltage source, such as, for example, a high-voltage network of an electric vehicle.
• the first connection A1 can be connected to the voltage source or separated from the voltage source, for example, by means of a suitable isolating switch.
• a capacitor such as an intermediate circuit capacitor CZ, can be arranged between the two connection elements Al-1 and Al-2.
• the DC voltage converter 1 comprises a second connection A2, which also has a first connection element A2-1 and a second connection element A2-2.
• the DC voltage converter 1 can be electrically coupled to a further voltage source, for example a low-voltage network of an electric vehicle or the like.
• a capacitor C can also be provided between the first connection element A2-1 and the second connection element A2-2.
• the DC voltage converter 1 comprises a first full bridge circuit 10.
• the first full bridge circuit 10 comprises two half bridges.
• the first half-bridge here comprises a series circuit of two switching elements 11 and 12, and the second half-bridge comprises a series circuit of the two switching elements 13 and 14.
• the DC converter 1 comprises a second full-bridge circuit 20.
• the second full-bridge circuit 20 can also have two half-bridges, each with two Switching elements 21-24 comprise.
• a first transformer TI is provided between the first full bridge circuit 10 and the second full bridge circuit 20. The primary side of the first transformer TI is connected at a connection to a first node of the first half bridge of the first full bridge circuit 10.
• a second connection of the primary side of the first transformer TI is connected to a further node point of the second half bridge of the first full bridge circuit 10.
• a first connection of the secondary side of the first transformer TI is connected to a node of the first half bridge of the second full bridge circuit 20
• a second connection of the secondary side of the first transformer TI is connected to a further node of the second half bridge of the second full bridge circuit 20.
• the turns ratio between the primary side and the secondary side of the first transformer TI is here, for example, N.
• N the turns ratio between the primary side and the secondary side of the first transformer TI
• the second full bridge circuit 20 is also coupled to the second connection A2 of the DC voltage converter 1.
• a connection element for example the second connection element A2-2, is connected directly to the second full bridge circuit 20.
• a series inductance is provided between the other connection element, for example the first connection element A2-1 of the second connection A2 and the second full bridge circuit 20.
• This series inductance can be implemented, for example, by means of a second transformer T2.
• a primary side of the second transformer T2 is arranged between the second full bridge circuit 20 and the first connection element A2-1 of the second connection A2.
• the secondary side of the second transformer T2 forms, together with a first switching element S1 and a first diode Dl, a series circuit which is arranged between the first connection element A2-1 and the second connection element A2-2 of the second connection A2.
• the first diode Dl is arranged in the forward direction, that is, the cathode of the first diode Dl points in the direction of negative polarity, and the anode of the first diode Dl points in the direction of positive polarity.
• the first switching element S1 is arranged between the first connection element A2-1 of the second connection and a first connection on the secondary side of the second transformer T2 and the first diode Dl between the second connection element A2-2 of the second connection A2 and a second connection on the secondary side of the second transformer T2 arranged.
• a second diode D2 can be provided in parallel with the first switching element S1.
• This second diode D2 can be arranged anti-parallel to the first diode D1, that is, the second diode D2 is arranged in the reverse direction, so that the cathode of the second diode D2 in the positive direction Has polarity at the second connection A2.
• a second switching element S2 can be provided in parallel with the first diode D1.
• the switching elements 21-24 of the second full bridge 20 as well as the first switching element S1 and possibly also the switching elements 11-14 of the first full bridge 10 and / or the second switching element S2 can be controlled, for example, by means of a suitable control device 30.
• the principle and the switching sequence in which the individual switching elements are activated will be explained in more detail below.
• energy can also be transferred when an electrical voltage U_prim is applied to the first connection A1 on the primary side, which is lower than the product of the transformation ratio N of the transformer and the voltage Ul_sek am second connection A2 of DC converter 1.
• FIG. 2 shows a schematic representation of the switching pattern and voltage / current curves of a control method for the DC voltage converter 1 according to one embodiment.
• the switching elements 21-24 of the second full bridge 20 and possibly also the switching elements 11-14 of the first full bridge 10 are open. Furthermore, the first switching element S1 is closed. Thus, an electric current I2_sek with an initially increasing current intensity flows through the first switching element S1, the secondary side of the second transformer T2 and the first diode D1. At time t1, the first switching element S1 is opened. Furthermore, the switching elements 11 and 14 of a diagonal branch are closed in the first full bridge circuit 10. The energy is transferred from the secondary side of the second transformer T2 to the primary side of the second transformer T2 and an electric current flows through the secondary side of the first transformer Tl.
• the electrical voltage Ul_sek across the secondary side of the first transformer leads to an energy transfer of the primary side of the DC converter 1 to the secondary side.
• the corresponding switching elements 21 and 24 of the second full bridge circuit 20 can be actively controlled for this purpose.
• the electrical current can also flow through the parallel body diodes.
• the switching elements 11-14 of the first full bridge circuit 10 and possibly the switching elements 21-24 of the second full bridge circuit 20 are opened. Furthermore, the first switching element S1 is closed and there is a renewed flow of current through the secondary side of the second transformer T2. At time t3, the first switching element S1 is opened again. Furthermore, the switching elements 12 and 13 in the second diagonal branch of the first full bridge circuit 10 are closed at time t3. Thus, the secondary side of the second transformer T2 is discharged again via the primary side of the second transformer T2 and there is now one via the secondary side of the first transformer T1 electrical voltage Ul_sek with reversed polarity. In this case, energy is also transferred from the primary side to the secondary side in this time interval.
• FIG. 3 shows a schematic representation of a flowchart on the basis of a method 100 for transferring energy from the primary side to the secondary side of a DC voltage converter according to one embodiment.
• a first step 110 the secondary side of the second transformer T2 is charged by closing the first switching element S1.
• the secondary side of the second transformer is discharged by opening the first Switching element and closing the switching elements in a diagonal branch of the first full-bridge circuit 10.
• the secondary side of the second transformer T2 is recharged by closing the first switching element S1.
• step 140 the secondary side of the second transformer T2 is again discharged, the first switching element S1 being opened again.
• the switching elements in the second diagonal branch of the first full bridge circuit 10 are closed.
• energy can be transferred from the primary side to the secondary side of the DC voltage converter 1.
• the energy transfer can in particular also take place when the electrical voltage at the first connection A1 on the primary side is less than the product of the transmission ratio and electrical voltage at the second connection on the secondary side of the DC voltage converter 1.
• the present invention relates to a circuit arrangement and a control method for a DC voltage converter, in particular a DC voltage converter with a phase-shifted fullbridge topology, with energy being transferred from the primary side to the secondary side even if the electrical voltage on the primary side is the product of electrical Voltage on the secondary side and transmission ratio of a transformer in the DC voltage converter falls below.
• a capacitor on the primary side of the DC voltage converter can be discharged to a safe, low voltage level.

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• Power Engineering (AREA)
• Dc-Dc Converters (AREA)

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• 2019
  • 2019-08-05 DE DE102019211692.2A patent/DE102019211692A1/de active Pending
• 2020
  • 2020-07-08 JP JP2022507421A patent/JP7291850B2/ja active Active
  • 2020-07-08 WO PCT/EP2020/069198 patent/WO2021023460A1/de unknown
  • 2020-07-08 US US17/632,269 patent/US11764695B2/en active Active
  • 2020-07-08 CN CN202080055735.8A patent/CN114175482A/zh active Pending
  • 2020-07-08 EP EP20739320.8A patent/EP4010973A1/de active Pending

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