CN215010058U

CN215010058U - DC-DC converter and power supply device

Info

Publication number: CN215010058U
Application number: CN202121328038.3U
Authority: CN
Inventors: 吴臻员
Original assignee: Shenzhen Xinsi Electric Energy Technology Co ltd
Current assignee: Shenzhen Xinsi Electric Energy Technology Co ltd
Priority date: 2021-06-15
Filing date: 2021-06-15
Publication date: 2021-12-03
Anticipated expiration: 2031-06-15

Abstract

The utility model discloses a DC-DC converter and power supply unit, this converter includes: the power supply input end is used for accessing a direct current power supply; the power supply output end is used for outputting a power supply; the input ends of the M bridge arm circuits are connected with the power supply input end; the primary coil connecting end of each transformer of the transformer assembly is connected with the central points of the M bridge arm circuits; the input end of the rectification filter circuit is connected with the secondary coil connecting end of the transformer assembly, and the output end of the rectification filter circuit is connected with the power supply output end; the M bridge arm circuits and the transformer assembly are used for converting an accessed direct-current power supply into required voltage at a secondary coil of the transformer assembly, and the required voltage is rectified and filtered by the rectifying and filtering circuit and then is output to a power supply output end; wherein M is more than or equal to 3. The utility model discloses the hindering nature loss of bridge arm circuit and transformer has been reduced, especially the afterflow loss.

Description

DC-DC converter and power supply device

Technical Field

The utility model relates to a power technical field, in particular to DC-DC converter and power supply unit.

Background

The traditional phase-shifted full-bridge architecture adjusts the output voltage by changing the duty ratio, refer to fig. 7 and 8, and fig. 7 is a circuit structure schematic of the phase-shifted full-bridge architecture DC-DC converterFIG. 8 is a timing diagram of the phase-shifted full-bridge DC-DC converter. The following analysis is based on the case where the inductance L1 minimum current is greater than zero. t0 free wheeling ends, Q₂₂And the leakage inductance of the transformer starts to enter a resonance state, and the voltage at the point V2 is charged. T1Q after the voltage at the point V2 reaches the highest point₂₁Soft on, Q₂₁And Q₁₂The transformer secondary side outputs energy after rectification. t2: Q₁₂And (6) turning off. The primary current of the transformer charges V1. T3Q after the voltage at the point V1 reaches the highest point₁₁Soft switching on. The transformer output voltage is 0. Transformers Tx, Q₁₁And Q₂₁And entering a freewheeling state. Energy is wasted on the transistor and transformer coils in this state. t4 free wheeling ends, Q₂₁And the leakage inductance of the transformer starts to enter a resonance state, and the voltage at the point V2 is discharged. T5Q after the voltage at V2 point reaches the lowest point₂₂Soft on, Q₂₂And Q₁₁The transformer secondary side outputs energy after rectification. t6: Q₁₁And (6) turning off. The primary current of the transformer discharges voltage at a point V1. T7Q after the voltage at V1 point reaches the lowest point₁₂Soft switching on. The transformer output voltage is 0. Transformers Tx, Q₁₂And Q₂₂And entering a freewheeling state. Energy is wasted on the transistor and transformer coils in this state. To cope with the transient variation of the load, the full duty cycle cannot be operated, and thus a freewheeling loss is introduced.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a DC-DC converter and power supply unit aims at reducing the hindering nature loss of bridge arm circuit and transformer, especially afterflow loss.

To achieve the above object, the present invention provides a DC-DC converter, including:

the power supply input end is used for accessing a direct current power supply;

the power supply output end is used for outputting a power supply;

the input ends of the M bridge arm circuits are connected with the power supply input end;

the primary coil connecting end of each transformer of the transformer assembly is connected with the central points of the M bridge arm circuits;

the input end of the rectification filter circuit is connected with the secondary coil connecting end of the transformer assembly, and the output end of the rectification filter circuit is connected with the power supply output end;

the M bridge arm circuits and the transformer assembly are used for converting the connected direct-current power supply into required voltage at a secondary coil of the transformer assembly, and the required voltage is rectified and filtered by the rectification filter circuit and then is output to the power output end; wherein M is more than or equal to 3.

Optionally, the transformer assembly includes M-1 transformers, each of the transformers includes two primary coil connection ends, and one of the primary coil connection ends of the nth transformer is connected to a bridge arm center point of the nth bridge arm circuit; the other primary coil connecting end of the Nth transformer is connected with the bridge arm central point of the (N + 1) th bridge arm circuit; wherein N is more than or equal to 1 and less than or equal to M-1.

Optionally, the DC-DC converter has an alternating phase-shifted full-bridge operation mode, a dual-mode operation mode, a semi-integrated operation mode, and a fully-integrated operation mode;

the DC-DC converter also comprises a main controller, and the main controller is respectively connected with the controlled ends of the bridge arm switches in the M bridge arm circuits; the main controller is used for controlling the on/off of corresponding bridge arm switches in the M bridge arm circuits when the DC-DC converter works so as to enable the transformer assembly to work in one or a combination of multiple modes of an alternate phase-shifted full-bridge working mode, a dual-mode working mode, a semi-integrated working mode and a fully-integrated working mode.

Optionally, when M is 3, the 3 bridge arm circuits include a first bridge arm switch, a second bridge arm switch, a third bridge arm switch, a fourth bridge arm switch, a fifth bridge arm switch, and a sixth bridge arm switch; wherein the content of the first and second substances,

the first bridge arm switch and the second bridge arm switch are connected in series to form a first bridge arm circuit;

the third bridge arm switch and the fourth bridge arm switch are connected in series to form a second bridge arm circuit;

and the fifth bridge arm switch and the sixth bridge arm switch are connected in series to form a third bridge arm circuit.

Optionally, in the alternating phase-shifted full-bridge operating mode, when the main controller controls the on/off of the two bridge arm switches of the second bridge arm circuit, the main controller controls the on/off of the two bridge arm switches of any one of the first bridge arm circuit and the third bridge arm circuit, and controls the two bridge arm switches of the other bridge arm circuit to be fully turned off.

Optionally, in the dual-mode working mode, the main controller controls the second bridge arm switch to be turned off first, and controls the fifth bridge arm switch to be turned on later; and controlling the first bridge arm switch to be turned off first, and controlling the sixth bridge arm switch to be turned on later.

The main controller controls the second bridge arm switch to be turned on first and controls the sixth bridge arm switch to be turned off later; and controlling the first bridge arm switch to be turned on first and controlling the fifth bridge arm switch to be turned off later.

Optionally, in the semi-integrated working mode or the fully integrated working mode, the main controller controls the third bridge arm switch to be turned on first and controls the first bridge arm switch to be turned off later; controlling the fourth bridge arm switch to be turned on first and controlling the second bridge arm switch to be turned off later;

the main controller controls the second bridge arm switch to be turned on first and controls the sixth bridge arm switch to be turned off later; controlling the first bridge arm switch to be turned on first and controlling the fifth bridge arm switch to be turned off later;

the main controller controls the fifth bridge arm switch to be switched on first and controls the fourth bridge arm switch to be switched on later; and controlling the sixth bridge arm switch to be switched on first and controlling the third bridge arm switch to be switched on later.

Optionally, the main controller controls on/off of corresponding bridge arm switches in the M bridge arm circuits, so that the transformer assembly works in a process of combining one or more of an alternate phase-shifted full-bridge working mode, a dual-mode working mode, a semi-integrated working mode and a fully-integrated working mode;

under an alternate phase-shifted full-bridge working mode, sequentially working M-1 transformers in turn for one or more control cycles in a phase-shifted full-bridge mode;

in a dual-mode working mode, after the 1 st to M-1 st transformers work with the voltage of the direct-current power supply in sequence in one control period, the M-1 st transformer continues current with zero voltage;

in a semi-integration working mode, after the 1 st to M-1 st transformers work with the direct-current power supply voltage in sequence in one control period, the M-1 transformers work simultaneously;

in a fully integrated operating mode, the 1 st to the M-1 st transformers are sequentially operated with the DC power supply voltage in one control period.

The utility model discloses still provide a power supply unit, include as above DC-DC converter.

The utility model discloses a DC-DC converter sets up M bridge arm circuits and transformer assembly and rectification filter circuit between power input end and power output end; the direct current power supply connected in is converted into required voltage through the M bridge arm circuits and the transformer assembly and then is output to the power supply output end through rectification and filtering, in the working process of the DC-DC converter, all transformers in the transformer assembly work in turn according to a certain time proportion and/or work simultaneously under the matching of the on/off of the bridge arm switches of all the bridge arm circuits in a corresponding time sequence, and the loss of the bridge arm switches during the on-state is reduced by utilizing the residual energy of the leakage inductance of the transformers and the charging/discharging of magnetizing current. The existing phase-shifted full-bridge architecture adjusts output voltage by changing duty ratio, but in order to deal with instant change of load, the full duty ratio can not work, and therefore follow current loss is introduced. The utility model reduces the resistive loss of the bridge arm circuit and the transformer, especially the follow current loss; and further, the size of the radiator of the DC-DC converter is reduced, and energy conservation and emission reduction are facilitated.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic circuit diagram of an embodiment of the DC-DC converter of the present invention;

fig. 2 is a schematic circuit diagram of another embodiment of the DC-DC converter of the present invention;

fig. 3 is a timing diagram of the DC-DC converter according to the present invention operating in the alternating phase-shifted full-bridge operating mode;

fig. 4 is a timing diagram illustrating the operation of the DC-DC converter in the dual-mode operation mode according to the present invention;

fig. 5 is a timing diagram illustrating the operation of the DC-DC converter in the semi-integration mode according to the present invention;

fig. 6 is a timing diagram illustrating the operation of the DC-DC converter in the fully integrated operation mode according to the present invention;

fig. 7 is a schematic circuit diagram of a conventional phase-shifted full-bridge DC-DC converter;

fig. 8 is a timing diagram of the phase-shifted full-bridge DC-DC converter of fig. 7.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				V-in	Power input terminal	20	Transformer assembly
V-out	Power supply output terminal	Tx₁～Tx_M-1	Transformer device
				10	Bridge arm circuit	Tx	Transformer device
11	First bridge arm circuit	Q₁₁，Q₁₂	First and second bridge arm switches
				12	Second bridge arm circuit	Q₂₁，Q₂₂	Third and fourth bridge arm switches
13	Third bridge arm circuit	Q₃₁，Q₃₂	Fifth and sixth bridge arm switch

The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that, if directional indications (such as upper, lower, left, right, front and rear … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The utility model provides a DC-DC converter.

Referring to fig. 1 to 6, in an embodiment of the present invention, the DC-DC converter includes:

the power supply input end V-in is used for connecting a direct current power supply;

the power output end V-out is used for outputting a power supply;

the bridge arm circuit comprises M bridge arm circuits 10, wherein the input ends of the M bridge arm circuits are connected with a power supply input end V-in, each bridge arm circuit comprises two switching tubes, the two switching tubes are connected in series, the bridge arm circuits are connected in parallel, and the switching tubes can be realized by power transistors such as an MOSFET (metal-oxide-semiconductor field effect transistor), an IGBT (insulated gate bipolar transistor), a GANFET (gate-induced field effect transistor), a SiFET (silicon-based field effect transistor) and the like;

a transformer assembly 20, wherein the primary coil connecting end of each transformer of the transformer assembly is connected with the central point of the M bridge arm circuits;

the transformer assembly 20 includes M-1 transformers Tx₁～Tx_M-1Each transformer comprises two primary coil connecting ends, and one primary coil connecting end of the Nth transformer is connected with the bridge arm central point of the Nth bridge arm circuit; the other primary coil connecting end of the Nth transformer is connected with the bridge arm central point of the (N + 1) th bridge arm circuit; wherein N is more than or equal to 1 and less than or equal to M-1.

Specifically, one primary coil connecting end of the 1 st transformer is connected with a bridge arm central point of the 1 st bridge arm circuit; the other primary coil connecting end of the 1 st transformer is connected with the bridge arm central point of the 2 nd bridge arm circuit; one primary coil connecting end of the 2 nd transformer is connected with the bridge arm central point of the 2 nd bridge arm circuit; the other primary coil connecting end of the 2 nd transformer is connected with the bridge arm central point of the 3 rd bridge arm circuit; by analogy, one primary coil connecting end of the M-1 th transformer is connected with the bridge arm central point of the M-1 th bridge arm circuit; the other primary coil connecting end of the M-1 th transformer is connected with the bridge arm central point of the Mth bridge arm circuit; the connection of the patent refers to electrical connection, and the patent does not limit a physical connection method of primary coil ends of two adjacent transformers and corresponding bridge arm central points.

The transformer coil of the transformer assembly 20 can be used for both step-down and step-up.

The input end of the rectifying and filtering circuit 30 is connected with the secondary coil connecting end of the transformer assembly 20, and the output end of the rectifying and filtering circuit 30 is connected with the power supply output end; the rectifying and filtering circuit 30 may be implemented by using elements such as a rectifying diode, an inductor, and a capacitor. Specifically, the DC-DC converter is provided with a diode for rectification on the secondary winding, i.e., the output side, of the transformer, and the diode may be a parasitic diode of the synchronous rectification transistor. The connection relationship of the diodes in the circuit can be adaptively adjusted according to the practical application, and is not limited herein. An inductor L1 and a capacitor C1 are arranged on the output side of the DC-DC converter, the inductor L1 is arranged between the secondary coil connecting end or the output end of the rectifier diode and the power output end V-out in series, and the capacitor C1 is arranged at the power output end V-out.

The M bridge arm circuits 10 and the transformer assembly 20 are configured to convert the connected dc power into a required voltage at a secondary winding of the transformer assembly 20, and output the required voltage to the power output terminal after being rectified and filtered by the rectification filter circuit 30; wherein M is more than or equal to 3.

The utility model discloses a DC-DC converter sets up M bridge arm circuits 10 and transformer assembly 20 and rectification filter circuit 30 between power input end V-in and power output end V-out; the connected dc power supply is converted into a required voltage through the M bridge arm circuits 10 and the transformer assembly 20, and the required voltage is output to the power output terminal V-out through the rectifier filter circuit 30. In the process of the operation of the DC-DC converter, each transformer in the transformer assembly 20 operates in turn according to a certain time proportion and/or operates simultaneously under the coordination of the on/off of the bridge arm switches of each bridge arm circuit in a corresponding time sequence, and the loss when the bridge arm switches are on is reduced by using the residual energy of the leakage inductance of the transformer and the magnetizing current for charging/discharging. The existing phase-shifted full-bridge architecture adjusts output voltage by changing duty ratio, but in order to deal with instant change of load, the full duty ratio can not work, and therefore follow current loss is introduced. The utility model reduces the resistive loss of the bridge arm circuit and the transformer, especially the follow current loss; further reducing the size of the radiator and being beneficial to energy conservation and emission reduction.

Referring to fig. 7 to 8, the number of turns of the primary winding and the secondary winding of the transformer Tx of the conventional phase-shifted full-bridge DC-DC converter is 2kN and 2k, respectively. Considering the situation of the positive and negative balance of the magnetic flux, the maximum magnetic flux B in the transformer Tx of the traditional phase-shifted full-bridge DC-DC converter_maxThe calculation formula of (2) is as follows:

VBUS is the DC power voltage, D is the equivalent duty cycle of the full-bridge transformer Tx, T is the switching period of the full-bridge DC-DC converter, 2kN is the number of turns of the primary winding of the full-bridge transformer Tx, and Ae is the equivalent cross-sectional area of the full-bridge transformer Tx.

Referring to fig. 1 to 6, in an embodiment, M is 3, a three-bridge architecture with three bridge arm circuits, and the number of adapted transformers is two. Two transformers Tx₁And Tx₂The transformer can work under the mode of having the same magnetic flux and also can work under the mode of asymmetric magnetic flux, and the maximum magnetic flux can be ensured not to exceed the maximum magnetic flux of the transformer material.

Three-bridge transformer Tx₁With the equivalent cross-sectional area of the new transformer core being maintained constant, i.e. Ae₁And (4) dividing the magnetic core of the full-bridge transformer into two parts (Ae), placing half of the primary coil and the secondary coil in half of the space, and supplementing the magnetic circuit along the cross section. Three-bridge transformer Tx₁The number of turns of the primary coil and the secondary coil is kN and k respectively, and compared with a full-bridge transformer, the resistance is reduced by half.

Three-bridge transformer Tx₂Using sum transformer Tx₁The number of turns of the same magnetic core, the primary winding and the secondary winding can be adjusted to pkN and k, wherein p is larger than or equal to 1.

Transformer Tx of three-bridge DC-DC converter with considering magnetic flux positive and negative balance₁Medium maximum magnetic flux B_1maxThe calculation formula of (2) is as follows:

wherein VBUS is the DC supply voltage, D₁For transformer Tx₁T is the switching period of the three-bridge DC-DC converter, kN is the transformer Tx₁Number of turns of primary winding, Ae and Ae₁For transformers Tx and Tx₁The equivalent cross-sectional area of (a).

When in use

When, B_1max＝B_maxThree-bridge transformer Tx₁Three-bridge transformer Tx, which is kept in agreement with the maximum flux of the full-bridge transformer Tx₁Normal operation can be maintained.

Considering the case where the steady-state inductor current is greater than zero, when D is small, Tx₂Only need to be at Tx₁After working D₂Duty ratio of D₂＝p(D-D₁) And satisfy D₁+D₂Less than or equal to 1, the sum equivalent output of the two transformers is identical to that of the traditional full-bridge transformer. When D is present₁+D₂When the value is equal to 1, the fully integrated working mode is entered. As D continues to increase, D maintains the same effect as a conventional full bridge₁Will be greater than

D₂＝1-D₁Whereby a transformer Tx appears₁And Tx₂The maximum magnetic fluxes are different, and the respective maximum magnetic fluxes must be controlled within the allowable range of the magnetic material of the transformer.

At steady state and same output voltage current, the three-bridge converter and the full-bridge converter have the same inductor current. For comparison, the three-bridge converter and the full-bridge converter use transistors of the same resistance.

Three-bridge transformer Tx₁The primary winding resistance of (a) is half of that of the full-bridge transformer Tx. The primary side current is the same as that of the full-bridge transformer in terms of inductive current and turn ratio when the transformer works independentlyAs well as the same. When the transformer works independently, the instantaneous resistive loss of the primary coil is half of that of a full-bridge transformer, and the instantaneous resistive loss of the transistor is the same as that of a full-bridge converter.

Three-bridge transformer Tx₂The coil space of the same primary side is filled by using p times of coil, the coil is necessarily thinned, and the sectional area is the former

The primary resistance is 0.5 × p of the primary resistance of the full-bridge transformer Tx²And (4) doubling. Since the three-bridge converter and the full-bridge converter have the same inductor current, the three-bridge transformer Tx₂Is p times that of the full-bridge transformer Tx, so that the three-bridge transformer Tx₂With primary current being full-bridge transformer Tx during independent operation

The instantaneous resistive loss of the primary winding being that of the full-bridge transformer Tx during its independent operation

And (4) doubling. With transistors having instantaneous losses of full-bridge converters

Multiple, less than 1 time.

Three-bridge transformer Tx₁And Tx₂Working simultaneously, Tx₁And Tx₂The primary winding of the transformer is connected in series, the secondary windings are connected in parallel, the sum of the secondary currents is an inductive current, and the primary current is calculated to be that of the full-bridge transformer Tx

Tx₁And Tx₂The total instantaneous loss of the primary winding being that of a full-bridge transformer Tx

Less than 0.25 times. With instantaneous loss of the primary transistor being that of a full-bridge converter

Less than 0.25 times.

Three-bridge transformer Tx₁And Tx₂The secondary winding resistance of (2) is half of the secondary winding resistance of the full-bridge transformer Tx. If Tx₁And Tx₂The transformer works independently, and the respective secondary instantaneous loss is half of that of the full-bridge transformer. If Tx₁And Tx₂Working simultaneously, Tx₁And Tx₂The secondary side coil is in parallel connection, and the total secondary side instantaneous loss is the secondary side instantaneous loss of the full-bridge transformer

Less than 0.25 times.

When the inductor current of the traditional full bridge architecture is larger than zero and the output voltage and current are steady, the balance of the inductor current can be obtained,

and VBUS is the direct-current power supply voltage, VOUT is the output power supply voltage, N is the primary side and secondary side turn ratio of the full-bridge transformer Tx, and D is the equivalent duty ratio of the transformer Tx.

When the inductor current is larger than zero in the full integration mode and the output voltage and the current are stable, the balance of the inductor current can be obtained,

D₂＝1-D₁

N₁＝N

N₂＝pN

wherein VBUS is the DC supply voltage, VOUT is the output power supply voltage, N₁And N₂Transformers Tx, respectively₁And Tx₂Primary side to secondary side winding turns ratio of D₁And D₂For transformer Tx₁And Tx₂The equivalent duty cycle of (a).

Through the simplification, the method can obtain the product,

the resistive loss of the phase-shifted full-bridge transistor is 1, the value of the phase-shifted full-bridge transistor after the follow current loss is removed is D, and the resistive loss of the transistor of the three-bridge transistor in the full integration mode is D

Simplified to obtain

Because D is less than 1, the resistive loss of the transistor of the three-bridge framework in the full integration mode is smaller than the value of the resistive loss of the transistor of the phase-shifted full-bridge framework after the follow current loss is removed.

In summary, under the condition that the total occupied space of the transformer is basically unchanged (the space of the transformer is doubled by the conventional Interleave architecture), compared with the full-bridge transformer, the three-bridge transformer Tx is adopted₁And Tx₂The total primary and secondary resistive losses are both reduced by at least half. If the skin effect and the proximity effect are considered, the total resistive loss of the two transformers of the three-bridge converter is reduced more after the number of coil turns is reduced. Under the dual-mode and semi-integrated working modes, the total resistance loss of bridge arm switching tubes in a primary bridge arm circuit of the three-bridge converter is reduced to a certain degree. In a fully integrated working mode, the total resistance loss of bridge arm switching tubes in a primary side bridge arm circuit of the three-bridge converter is smaller than the value of a phase-shifted full-bridge framework after the follow current loss is removed.

Referring to fig. 1 to 6, in an embodiment, the present invention provides a transformer Tx of a three-bridge DC-DC converter₁The number of turns of the primary coil and the secondary coil can be kept the same as that of the transformer of the full-bridge DC-DC converter2kN and 2k, respectively, in which case a core with a half-cross-sectional area, ie₁0.5 Ae. Considering the condition of positive and negative balance of magnetic flux, the utility model discloses transformer Tx of three-bridge framework DC-DC converter₁Maximum magnetic flux B of_1maxThe calculation formula of (2) is as follows:

wherein VBUS is the DC supply voltage, D₁For transformer Tx₁T is the switching period of the three-bridge DC-DC converter, 2kN is the transformer Tx₁Number of turns of primary winding, Ae and Ae₁For transformers Tx and Tx₁The equivalent cross-sectional area of (a).

When in use

When, B_1max＝B_max. The transformer Tx is reduced in area by half as compared to a full-bridge transformer₁The core coil perimeter is 0.707 of the full bridge transformer Tx, and the primary and secondary resistances can be reduced by about 29% using the same size coil. This example uses less magnetic material than the previous example.

Transformer Tx of this example₂Reference is made to the previous examples.

Referring to fig. 1 to 6, in an embodiment, the DC-DC converter has an alternating phase-shifted full-bridge operation mode, a dual-mode operation mode, a semi-integrated operation mode, and a fully integrated operation mode;

the DC-DC converter also comprises a main controller, and the main controller is respectively connected with the controlled ends of the bridge arm switches in the M bridge arm circuits; the main controller is configured to control on/off of corresponding bridge arm switches in the M bridge arm circuits when the DC-DC converter operates, so that the transformer assembly 20 operates in one or a combination of multiple modes of an alternate phase-shifted full-bridge operating mode, a dual-mode operating mode, a semi-integrated operating mode, and a fully integrated operating mode.

In this embodiment, when the DC-DC converter operates in the alternating phase-shifted full-bridge operation mode, the dual-mode operation mode, the semi-integrated operation mode, and the fully-integrated operation mode, the 4 modes have different timings and can be applied to different duty ratios. An alternate phase-shifted full-bridge mode of operation or a dual-mode of operation may be used when the equivalent full-bridge duty cycle (i.e., the duty cycle required using the conventional full-bridge approach) is relatively small. A semi-integral mode of operation or a fully integral mode of operation may be used when the equivalent full bridge duty cycle is relatively large.

Referring to fig. 1 to 6, in an embodiment, when M is 3, 3 bridge arm circuits include a first bridge arm switch Q₁₁And a second bridge arm switch Q₁₂And a third bridge arm switch Q₂₁And a fourth bridge arm switch Q₂₂And a fifth bridge arm switch Q₃₁And a sixth arm switch Q₃₂(ii) a Wherein the content of the first and second substances,

the first bridge arm switch Q₁₁And said second leg switch Q₁₂The first bridge arm circuit 11 is formed by series connection; the third bridge arm switch Q₂₁And said fourth leg switch Q₂₂The second bridge arm circuit 12 is formed by series connection; the fifth bridge arm switch Q₃₁And said sixth leg switch Q₃₂The series arrangement constitutes a third bridge arm circuit 13.

In the embodiment where the transformer assembly 20 includes M-1 transformers, when M is 3, 3 bridge arm circuits and 2 transformers constitute a three-bridge DC-DC converter, and each of the two transformers is a transformer Tx₁And Tx₂The transformer Tx₁One end of the primary coil of (a) is connected to the bridge arm center point of the first bridge arm circuit 11, and a transformer Tx₁The other end of the primary winding of (a) is connected with the bridge arm center point of the second bridge arm circuit 12, and a transformer Tx₂One end of the primary winding of (a) is connected to the bridge arm center point of the second bridge arm circuit 12, and a transformer Tx₂The other end of the primary coil is connected to the bridge arm center of the third bridge arm circuit 13. Each bridge arm switch is switched on or switched off according to the difference of high and low levels of the received driving signals, and each bridge arm switch can be switched on when receiving the driving signals with the high levels and can be switched on when receiving the driving signals with the low levelsCutting off; alternatively, the switch is turned on when a low-level driving signal is received and turned off when a high-level driving signal is received. In the embodiment, each bridge arm switch receives a high-level driving signal to be turned on, and is turned off when a low-level driving signal is received, when each bridge arm switch tube is turned on/off, the primary coil and the connected direct-current power supply form a current loop through the turned-on bridge arm switch tube, so that the current of the connected direct-current power supply flows through the primary coil, the electric energy is coupled to the secondary coil of the transformer assembly 20, and is rectified and filtered by the rectifying and filtering circuit 30 to be converted into a power supply which is then output to a power load, and the conversion and isolated output of the direct-current power supply are realized. When M is larger than 3, the M bridge arm circuits and the M-1 transformers form a transformer of the M-bridge DC-DC converter, wherein the M1 th bridge arm switch Q_M1And said M2 bridge arm switch Q_M2And the M bridge arm circuit 1M is formed by series connection.

Referring to fig. 1, 2 and 3, in an embodiment, in the alternating phase-shifted full-bridge operating mode, when the main controller controls the two bridge arm switches of the second bridge arm circuit 12 to be turned on/off, the main controller controls the two bridge arm switches of any one of the first bridge arm circuit 11 and the third bridge arm circuit 13 to be turned on/off, and controls the two bridge arm switches of the other bridge arm circuit to be turned off completely.

Referring to fig. 3, fig. 3 is a timing chart of the driving signal received by each bridge arm switch in the alternating phase-shifted full-bridge operating mode. The following analysis is based on the inductance L1 being greater than zero for minimum current.

time t0 fourth leg switch Q before time t0₂₂And a sixth arm switch Q₃₂And the other bridge arm switches are in an on state and in a stop state. When time t0 comes, fourth arm switch Q₂₂When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to increase in voltage.

At the moment t1, when the voltage of the bridge arm central point V2 of the second bridge arm circuit 12 reaches the highest point, the third bridge arm switch Q₂₁Soft switching on. At this time, the transformer Tx₂The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

At time t2, sixth leg switch Q₃₂And is turned off, the bridge arm center point V3 voltage of the third bridge arm circuit 13 starts to rise.

At the time t3, when the voltage of the bridge arm central point V3 of the third bridge arm circuit 13 reaches the highest point, the fifth bridge arm switch Q₃₁Soft switching on. Transformer Tx₂Third arm switch Q₂₁And a fifth leg switch Q₃₁The freewheeling state is started.

time t4, third arm switch Q₂₁When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to decrease in voltage.

At time t5, when the bridge arm center point V2 of the second bridge arm circuit 12 reaches the lowest point, the fourth bridge arm switch Q₂₂Soft switching on. At this time, the transformer Tx₂The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

At time t6, fifth leg switch Q₃₁And is turned off, and the bridge arm center point V3 of the third bridge arm circuit 13 starts to decrease in voltage.

Transformer Tx between time t6 to time t7₂Fourth leg switch Q₂₂And a sixth arm switch Q₃₂During freewheeling, the sixth arm switch Q₃₂The synchronous rectification may be turned on or off. If on, Q32 needs to be off before time t 8.

At time t7, arm center point V1 of first arm circuit 11 automatically reaches the lowest voltage due to the influence of the arm center point V2 voltage of second arm circuit 12 and the arm center point V3 voltage of third arm circuit 13. At this time, the second bridge arm switch Q₁₂Soft switching on.

Fourth leg switch Q at time t8₂₂When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to increase in voltage.

At the moment t9, when the voltage of the bridge arm central point V2 of the second bridge arm circuit 12 reaches the highest point, the third bridge arm switch Q₂₁Soft switching on. At this time, the transformer Tx₁The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

Second leg switch Q at time t10₁₂And is turned off, the bridge arm center point V1 of first bridge arm circuit 11 begins to rise in voltage.

At the time t11, when the voltage of the bridge arm center point V1 of the first bridge arm circuit 11 reaches the highest point, the first bridge arm switch Q₁₁Soft switching on. Transformer Tx₁Third arm switch Q₂₁And a first leg switch Q₁₁And entering a freewheeling state.

time t12, third arm switch Q₂₁When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to decrease in voltage.

At time t13, when the bridge arm center point V2 of the second bridge arm circuit 12 reaches the lowest point, the fourth bridge arm switch Q₂₂Soft switching on. At this time, the transformer Tx₁The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

time t14 first leg switch Q₁₁And is turned off, and the bridge arm center point V1 of first bridge arm circuit 11 starts to decrease in voltage.

Transformer Tx between time t14 to time t15₁Second leg switch Q₁₂And a fourth leg switch Q₂₂Second arm switch Q during freewheeling₁₂The synchronous rectification may be turned on or off. If on, Q is before time t0₁₂A shutdown is required.

At time t15, arm center point V3 of third arm circuit 13 automatically reaches the lowest voltage due to the influence of the arm center point V2 voltage of second arm circuit 12 and the arm center point V1 voltage of first arm circuit 11. Sixth bridge arm switch Q₃₂Soft switching on.

the time period t0-t15 is repeated in a cycle.

If satisfied, acts on the transformer Tx₂Is longer than the transformer Tx₁And the transformer can be automatically reset by the alternate operation of the residual magnetism reset time. No intervention of any other method (such as dc blocking capacitors Cb1, Cb2, current sampling, etc.) is required. Suppose transformer Tx₁Time product change of forward working voltage to VT₁Time product of negative working voltage is changed to VT₂The voltage-time product of the remanence is then (VT)₁-VT₂) In the positive and negative directionsVoltage-time product of remanence (VT) when driven symmetrically₁-VT₂) Time product variation VT with respect to forward operating voltage₁Or negative working voltage time product change VT₂Is a very small value. Transformer Tx₂When working in positive or negative direction, the transformer Tx can be used for more than a reasonable time₁Is reset, so that the transformer Tx₁Can always be reset. Transformer Tx for the same reason₂Will also be transformed by the transformer Tx₁And resetting.

In the above embodiment, the period t0-t7 is referred to as phase A. the time t8-t15 is referred to as phase B. The whole working time sequence can be the alternate working of A-B-A-B, and can also be the alternate working of a plurality of A continuously working and then a plurality of B continuously working. During the time period t0-t15, (third arm switch Q)₂₁Fourth leg switch Q₂₂) In operation, (first leg switch Q)₁₁Second leg switch Q₁₂) Or (fifth leg switch Q)₃₁The sixth arm switch Q₃₂) Only one pair is in operation and the other pair is fully off. The operation of the bridge arm switch refers to switching on/off at a certain duty ratio according to the time sequence of the driving signal.

Referring to fig. 1, 2 and 4, in an embodiment, in the dual-mode operation mode, the main controller controls the second bridge arm switch Q₁₂First, the switch is turned off to control the fifth bridge arm switch Q₃₁Then opening; controlling the first bridge arm switch Q₁₁First, the sixth bridge arm switch Q is controlled to be turned off₃₂Then opening;

the main controller controls the second bridge arm switch Q₁₂Firstly, the sixth bridge arm switch Q is controlled to be switched on₃₂Then the power is turned off; controlling the first bridge arm switch Q₁₁Firstly, the fifth bridge arm switch Q is controlled to be switched on₃₁And then is turned off.

Referring to fig. 4, fig. 4 is a timing diagram of the driving signal received by each bridge arm switch in the dual-mode operation mode. The following analysis is based on the case where the inductance L1 minimum current is greater than zero.

Second leg switch Q at time t0₁₂And a fourth leg switch Q₂₂When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to increase in voltage.

At the time t1, when the voltage of the bridge arm center point V2 of the second bridge arm circuit 12 reaches the highest point, the third bridge arm switch Q₂₁Open, transformer Tx₂The secondary coil outputs energy outwards after rectification.

Second leg switch Q at time t2₁₂Open, transformer Tx₁The secondary coil outputs energy outwards after rectification.

At time t3, sixth leg switch Q₃₂And (6) turning off. Sixth bridge arm switch Q₃₂After the turn-off, the residual energy of the leakage inductance and the magnetizing current charge the bridge arm center point V3 of the third bridge arm circuit 13.

Second leg switch Q at time t4₁₂And (6) turning off.

time t5: after passing through a dead zone, the first bridge arm switch Q₁₁And a fifth leg switch Q₃₁And (4) opening. Transformer Tx₁First leg switch Q11 and third leg switch Q21 enter a freewheeling state.

time t6 first leg switch Q₁₁And a third arm switch Q₂₁When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to decrease in voltage.

At time t7, when the bridge arm center point V2 of the second bridge arm circuit 12 reaches the lowest point, the fourth bridge arm switch Q₂₂Open, transformer Tx₂The secondary coil outputs energy outwards after rectification.

time t8 first leg switch Q₁₁Open, transformer Tx₁The secondary coil outputs energy outwards after rectification.

At time t9, fifth leg switch Q₃₁And (6) turning off. Fifth bridge arm switch Q₃₁After the turn-off, the residual energy of the leakage inductance and the magnetizing current discharge the bridge arm center point V3 of the third bridge arm circuit 13.

time t10 first leg switch Q₁₁And (6) turning off.

At time t11, after a dead zone, the second leg switch Q₁₂And a sixth arm switchQ₃₂And (4) opening. Transformer Tx₁Second leg switch Q₁₂And a fourth leg switch Q₂₂And entering a freewheeling state.

the time period t0-t11 is repeated in a cycle.

In the above embodiment, the main controller controls the timing of the driving signal in the above manner, and turns on/off at a certain duty ratio.

Referring to fig. 1, 2, 5 and 6, in an embodiment, the main controller controls the third bridge arm switch Q in the semi-integration operation mode or the full-integration operation mode₂₁Firstly, the first bridge arm switch Q is switched on and controlled₁₁Then the power is turned off; controlling the fourth leg switch Q₂₂Firstly, the second bridge arm switch Q is controlled to be switched on₁₂Then the power is turned off;

the main controller controls the second bridge arm switch Q₁₂Firstly, the sixth bridge arm switch Q is controlled to be switched on₃₂Then the power is turned off; controlling the first bridge arm switch Q₁₁Firstly, the fifth bridge arm switch Q is controlled to be switched on₃₁Then the power is turned off;

the main controller controls the fifth bridge arm switch Q₃₁Firstly, the fourth bridge arm switch Q is controlled to be switched on₂₂Then switching on to control the sixth bridge arm switch Q₃₂Firstly, the third bridge arm switch Q is controlled to be switched on₂₁Then the switch is turned on.

Referring to fig. 5, fig. 5 is a timing diagram of driving signals received by each bridge arm switch in the semi-integrated operation mode. The following analysis is based on the case where the inductance L1 minimum current is greater than zero.

time t0, third arm switch Q₂₁Opening, Tx₂After rectification, the energy is output separately.

time t1 first leg switch Q₁₁Off, the magnetizing current discharges leg center point V1 of first leg circuit 11.

Second leg switch Q at time t2₁₂Is turned on, at this time, the transformer Tx₁After rectification, the energy is output separately.

At time t3, sixth leg switch Q₃₂And (6) turning off.Tx is utilized between t3-t4₂Residual leakage inductance energy and magnetizing current charge the bridge arm central point V3 of the third bridge arm circuit 13, and the fifth bridge arm switch Q is reduced₃₁Loss at turn-on.

time t4, third arm switch Q₂₁And (6) turning off. Fifth bridge arm switch Q₃₁And (4) opening. Transformer Tx between t4-t5₁And a transformer Tx₂After rectification, the energy is output outwards together.

Fourth leg switch Q at time t5₂₂And (4) opening. At this time, the transformer Tx₂After rectification, the energy is output separately.

Second leg switch Q at time t6₁₂Off, the magnetizing current charges the leg center point V1 of first leg circuit 11.

time t7 first leg switch Q₁₁Open, transformer Tx₁After rectification, the energy is output separately.

At time t8, fifth leg switch Q₃₁And (6) turning off. Maximum utilization of transformer Tx in time period t8-t9₂The residual energy of leakage inductance and the magnetizing current discharge the bridge arm central point V3 of the third bridge arm circuit 13, and the sixth bridge arm switch Q is reduced₃₂Loss at turn-on.

Fourth leg switch Q at time t9₂₂And (6) turning off. Sixth bridge arm switch Q₃₂And (4) opening. Transformer Tx between t9-t0₁And a transformer Tx₂After rectification, the energy is output outwards together.

the time period t0-t9 is repeated in a cycle.

In this mode, Tx₂->Tx₁->(Tx₁And Tx₂Working together) there is no transformer both voltage output is zero and there is a freewheeling state where current is present, no freewheeling loss. In the above embodiment, the main controller controls the timing of the driving signal in the above manner, and turns on/off at a certain duty ratio.

Referring to fig. 6, fig. 6 is a timing chart of the driving signals received by each bridge arm switch in the full integration operation mode. The following analysis is based on the case where the inductance L1 minimum current is greater than zero.

time t0:when the bridge arm center point V2 voltage of the second bridge arm circuit 12 rises to the highest point, the third bridge arm switch Q₂₁And (4) opening. Transformer Tx₂After rectification, the energy is output separately.

Second leg switch Q at time t2₁₂Open, transformer Tx₁After rectification, the energy is output separately.

At time t3, sixth leg switch Q₃₂And (6) turning off. Maximum Tx utilization at time t3-t4₂Residual leakage inductance energy and magnetizing current charge the bridge arm central point V3 of the third bridge arm circuit 13, and the fifth bridge arm switch Q is reduced₃₁Loss at turn-on. Fifth bridge arm switch Q₃₁Turned on at some time between times t3-t 4.

time t4, third arm switch Q₂₁And (6) turning off. Resonance begins and the bridge leg center point V2 voltage of second bridge leg circuit 12 begins to decrease.

At time t5, the bridge arm center point V2 of the second bridge arm circuit 12 has its lowest voltage, and the fourth bridge arm switch Q has its lowest voltage₂₂And (4) opening. Transformer Tx₂After rectification, the energy is output separately.

At time t8, fifth leg switch Q₃₁And (6) turning off. Maximum utilization of transformer Tx at time t8-t9₂The residual energy of leakage inductance and the magnetizing current discharge the bridge arm central point V3 of the third bridge arm circuit 13, and the sixth bridge arm switch Q is reduced₃₂Loss at turn-on. Sixth bridge arm switch Q₃₂Turned on at some time between times t8-t 9.

Fourth leg switch Q at time t9₂₂Off, resonance begins and the bridge leg center point V2 of second bridge leg circuit 12 begins to rise in voltage.

the time period t0-t9 is repeated in a cycle.

In this mode, the transformer Tx₂And a transformer Tx₁The alternating DC power supply works with the voltage, no transformer is provided, the voltage output is zero, the current continues to flow, and no current continues loss exists. In the above embodiment, the main controller controls the timing of the driving signal in the above manner, and turns on/off at a certain duty ratio.

Referring to fig. 1-6, in one embodiment, the transformer assembly 20 includes M-1 transformers Tx₁～Tx_M-1More than 2 transformers with different turn ratios can be arranged in the M-1 transformers, and each transformer comprises two primary coil connecting ends;

one primary coil connecting end of the Nth transformer is connected with the bridge arm central point of the Nth bridge arm circuit; the other primary coil connecting end of the Nth transformer is connected with the bridge arm central point of the (N + 1) th bridge arm circuit in common; wherein N is more than or equal to 1 and less than or equal to M-1; the main controller controls the on/off of corresponding bridge arm switches in the M bridge arm circuits, so that the transformer assembly 20 works in one or a combination of a plurality of modes of an alternate phase-shifted full-bridge working mode, a dual-mode working mode, a semi-integrated working mode and a fully-integrated working mode;

in the alternative phase-shifted full-bridge mode of operation, M-1 transformers Tx₁～Tx_M-1Matched with M bridge arm circuits 10, M-1 transformers Tx₁～Tx_M-1And sequentially working one or more control cycles in a phase-shifted full-bridge mode in turn, specifically, in one cycle, after the 1 st transformer works one or more control cycles in the phase-shifted full-bridge mode, the 2 nd transformer works one or more control cycles again until the M-1 st transformer is completed. And in the next cycle, the 1 st transformer is connected with the M-1 st transformer in a seamless mode to work, and the cycle is carried out. Under a dual-mode working mode, after the 1 st to M-1 st transformers work with the DC power supply voltage in sequence in one control period, the M-1 st transformer Tx_M-1Follow current in zero voltage mode, next control cycle, 1 st changeThe transformer is connected with the M-1 th transformer in a seamless mode to start working. In a semi-integration working mode, after the 1 st to M-1 st transformers work with the DC power supply voltage in sequence in one control period, M-1 transformers Tx₁～Tx_M-1And simultaneously working (only the upper tube of the first bridge arm circuit and the lower tube of the last bridge arm circuit are switched on, or only the lower tube of the first bridge arm circuit and the upper tube of the last bridge arm circuit are switched on), starting working after the 1 st transformer is connected in a seamless mode in the next control period, and having no follow current loss in the mode. In a full integration working mode, the 1 st to M-1 st transformers work with the direct-current power supply voltage in sequence in one control period, and in the next control period, the 1 st transformer is connected with the M-1 st transformer in a seamless mode to start working, and no follow current loss exists in the mode.

Referring to fig. 1 to 6, in the above embodiment, in the M bridge structure, M is greater than or equal to three, the DC-DC converter may further include blocking capacitors, each blocking capacitor is connected in series with a primary winding of the transformer requiring magnetic balance, and the number of the blocking capacitors may be set according to the number of the transformers. In an embodiment where the DC-DC converter has M-1 transformers, for example, when M is 3, DC blocking capacitor Cb1 may be disposed at bridge arm center point V1 and transformer Tx of first bridge arm circuit 11₁May also be provided between the bridge arm center point V2 of second bridge arm circuit 12 and transformer Tx₁And the other of the primary coil connection terminals. In the same way, at the transformer Tx₂Between one of said primary coil connection terminals and the leg center point V2 of the second leg circuit 12 or at the transformer Tx₂A dc blocking capacitor may also be provided between the other primary coil connection end and the bridge arm center point V3 of the third bridge arm circuit 13. The M-1 transformers are connected to the M half-bridges with or without dc blocking capacitors.

The detailed structure of the DC-DC converter can refer to the above embodiments, and is not described herein; it can be understood that, because the utility model discloses above-mentioned DC-DC converter has been used in power supply unit, consequently, the embodiment of the utility model discloses power supply unit includes all technical scheme of the whole embodiments of above-mentioned DC-DC converter, and the technical effect that reaches is also identical, no longer explains herein.

The above is only the optional embodiment of the present invention, and not the scope of the present invention is limited thereby, all the equivalent structure changes made by the contents of the specification and the drawings are utilized under the inventive concept of the present invention, or the direct/indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A DC-DC converter, characterized in that the DC-DC converter comprises:

the power supply input end is used for accessing a direct current power supply;

the power supply output end is used for outputting a power supply;

2. The DC-DC converter of claim 1, wherein said transformer assembly comprises M-1 transformers, each of said transformers comprising two primary winding connections, one of said primary winding connections of an nth of said transformers being connected to a leg center of an nth of said leg circuits; the other primary coil connecting end of the Nth transformer is connected with the bridge arm central point of the (N + 1) th bridge arm circuit; wherein N is more than or equal to 1 and less than or equal to M-1.

3. The DC-DC converter of claim 1, wherein the DC-DC converter has an alternating phase-shifted full-bridge mode of operation, a dual-mode of operation, a semi-integrated mode of operation, and a fully integrated mode of operation;

4. The DC-DC converter according to claim 3, wherein when M is 3, 3 bridge arm circuits comprise a first bridge arm switch, a second bridge arm switch, a third bridge arm switch, a fourth bridge arm switch, a fifth bridge arm switch and a sixth bridge arm switch; wherein the content of the first and second substances,

5. The DC-DC converter according to claim 4, wherein in the alternating phase-shifted full-bridge operation mode, the main controller controls the two bridge arm switches of any one of the first bridge arm circuit and the third bridge arm circuit to be turned on/off and controls the two bridge arm switches of the other bridge arm circuit to be turned off completely while controlling the two bridge arm switches of the second bridge arm circuit to be turned on/off.

6. The DC-DC converter according to claim 4, wherein in the dual-mode operation mode, the main controller controls the second bridge arm switch to be turned off first and controls the fifth bridge arm switch to be turned on later; controlling the first bridge arm switch to be turned off first, and controlling the sixth bridge arm switch to be turned on later;

7. The DC-DC converter according to claim 4, wherein in the semi-integrated operation mode or the fully integrated operation mode, the main controller controls the third bridge arm switch to be turned on first and then turned off after controlling the first bridge arm switch; controlling the fourth bridge arm switch to be turned on first and controlling the second bridge arm switch to be turned off later;

8. The DC-DC converter according to claim 3, wherein the main controller controls the corresponding bridge arm switches of the M bridge arm circuits to be turned on/off, so that the transformer assembly operates in one or a combination of a plurality of alternating phase-shifted full-bridge operation mode, a dual-mode operation mode, a semi-integrated operation mode and a fully integrated operation mode;

9. A power supply apparatus comprising a DC-DC converter according to any one of claims 1 to 8.