CN115021576A

CN115021576A - DC-DC converter and power supply device

Info

Publication number: CN115021576A
Application number: CN202210670929.XA
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: 2022-06-14
Publication date: 2022-09-06
Also published as: CN118318382A; CN113258787A

Abstract

The invention discloses a DC-DC converter and a power supply device, the converter includes: the power supply input end is set to be connected with a direct current power supply; the power supply output end is arranged to output 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 arranged to convert 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 output to a power supply output end; wherein M is more than or equal to 3.

Description

DC-DC converter and power supply device

RELATED APPLICATIONS

The present invention claims priority from the chinese application No. 202110663929.2, filed on 15, 6/2021, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates to power supply technologies, and in particular, to a DC-DC converter and a power supply apparatus.

Background

The traditional phase-shifted full-bridge architecture adjusts the output voltage by changing the duty ratio, referring to fig. 7 and 8, fig. 7 is a schematic diagram of the circuit structure of the phase-shifted full-bridge architecture DC-DC converter, and fig. 8 is a timing diagram of the phase-shifted full-bridge architecture DC-DC converter. The following analysis is based on the case where the inductance L1 minimum current is greater than zero. t 0: afterflow is over, Q ₂₂ And when the voltage is turned off, the leakage inductance of the transformer starts to enter a resonance state, and the voltage at the point V2 is charged. t 1: q after voltage at point V2 reaches the maximum ₂₁ Soft on, Q ₂₁ And Q ₁₂ The transformer secondary side outputs energy after rectification. t 2: q ₁₂ And (6) turning off. The primary current of the transformer charges V1. t 3: q after voltage reaches the maximum point at V1 ₁₁ Soft switching on. The transformer output voltage is 0. Transformers Tx, Q ₁₁ And Q ₂₁ And entering a freewheeling state. Energy is wasted on the transistor and transformer coils in this state. t 4: afterflow is over, Q ₂₁ And the leakage inductance of the transformer starts to enter a resonance state, and the voltage at the point V2 is discharged. t 5: q after the voltage at the point V2 reaches the lowest point ₂₂ Soft on, Q ₂₂ And Q ₁₁ The transformer secondary side outputs energy to the outside after rectification. t 6: q ₁₁ And (6) turning off. The primary current of the transformer discharges voltage at a point V1. t 7: q after the voltage at the point V1 reaches the lowest point ₁₂ Soft switching on. The transformer output voltage is 0. Transformers Tx, Q ₁₂ And Q ₂₂ And 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.

Content of application

The invention mainly aims to provide a DC-DC converter and a power supply device, aiming at reducing the resistive loss, particularly the follow current loss, of a bridge arm circuit and a transformer.

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

the power supply input end is set to be connected with a direct current power supply;

the power supply output end is arranged to output a power supply;

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

the transformer assembly comprises M-1 transformers, and at least 2 transformers with different turn ratios are arranged in the M-1 transformers; each 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;

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 arranged to convert 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.

In one embodiment, the state of two adjacent transformers is changed simultaneously by changing the state of switches of the two adjacent transformers sharing the bridge arm circuit.

In one embodiment, when one of the M-1 transformers has a transformer with at least one end suspended, a lower tube of a bridge arm circuit from which a magnetizing current flows out of two bridge arm center points connected to a primary coil connection end is switched on, and an upper tube of the bridge arm circuit from which the magnetizing current flows in of the bridge arm center points is switched on, so that the switching loss of the bridge arm circuit is minimized.

In one embodiment, when one of the M-1 transformers has a transformer with at least one suspended end, a lower tube is connected to a bridge arm circuit from which a magnetizing current flows out in two bridge arm central points connected to a primary coil connecting end, and an upper tube is connected to a bridge arm circuit from which a magnetizing current flows in the bridge arm central points, so that switching loss of the bridge arm circuit is minimized; and the other transformer which is connected with the direct current power supply to work keeps the switching state of the bridge arm unchanged and continues to work, so that the two transformers are connected with the direct current power supply to work simultaneously.

In one embodiment, the DC-DC converter has an alternating phase-shifted full-bridge operation mode, in which M-1 primary sides of the transformers are sequentially operated with the DC power voltage and a zero voltage for one or more control cycles; or

In a control period, one of the transformers is firstly connected with the direct-current power supply through the corresponding bridge arm to work, then the two ends of the transformer are in short circuit work through the corresponding bridge arm, the transformer works in one or more control periods in this way, and M-1 transformers work in a circulating mode in sequence.

In one embodiment, the DC-DC converter has a dual-mode operation mode, and in the dual-mode operation mode, after the 1 st to M-1 st transformers operate with the DC power voltage in sequence in one control cycle, the M-1 st transformer continues current with zero voltage; or

When the last transformer is switched to work, the last two transformers are simultaneously connected with the direct-current power supply to work; or

Starting a cycle of the M-1 transformers from any transformer in a control period, sequentially connecting the direct-current power supply to work through corresponding bridge arms, and enabling the last transformer to carry out short-circuit follow current on two ends of the last transformer through the corresponding bridge arms after the cycle; or

When the last transformer is switched to work, the last two transformers are simultaneously connected with the direct current power supply to work.

In one embodiment, the DC-DC converter has a semi-integral operation mode, and in the semi-integral operation mode, after the 1 st to M-1 st transformers operate with the DC power voltage in sequence in one control period, the M-1 transformers operate simultaneously; or

In the semi-integration working mode, starting one cycle of the M-1 transformers from any transformer in one control period, sequentially connecting the direct-current power supplies to work through corresponding bridge arms, and simultaneously connecting the M-1 transformers in series after the cycle; or

In one embodiment, the DC-DC converter has a fully integrated operation mode in which the 1 st to M-1 st transformers are sequentially operated at the DC power voltage during one control cycle; or

Under the full-integration working mode, adjusting a control period according to the input voltage and the change of the duty ratio of each transformer, so that the maximum magnetic flux of any one of the M-1 transformers does not exceed the maximum allowable value of a magnetic material; or

In a control period, starting a cycle from any transformer by the M-1 transformers, and sequentially connecting the direct-current power supplies to work through corresponding bridge arms; or

In one 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;

under an alternate phase-shifted full-bridge working mode, the primary sides of the M-1 transformers sequentially work for one or more control cycles with the direct-current power supply voltage and zero voltage;

under a dual-mode working mode, after the primary sides of the 1 st to the 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 primary sides of 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 transformers work simultaneously;

under a full-integration working mode, the primary sides of the 1 st to the M-1 st transformers work with the voltage of the direct-current power supply in sequence in one control period;

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.

In one embodiment, in the dual-mode operation mode, or in the semi-integrated operation mode, or in the fully integrated operation mode, when the last transformer is switched to operate, the last two transformers are simultaneously connected to the direct-current power supply to operate.

In one embodiment, in the fully integrated operation mode, the control period is adjusted according to the input voltage and the duty ratio of each transformer, so that the maximum magnetic flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material.

In one embodiment, the switching between any two modes has a hysteresis of the change in the equivalent full-bridge duty cycle as the equivalent full-bridge duty cycle changes.

In one embodiment, the DC-DC converter has an alternate full-bridge operation mode, in which one of the M-1 transformers firstly switches on the DC power supply through a corresponding bridge arm during one control period, and then switches off the bridge arm connected to the transformer to suspend the input end of the transformer, the transformer operates in this way for one or more control periods, and the M-1 transformers sequentially operate in a cycle.

In an embodiment, the DC-DC converter has an individual full-bridge operation mode, in which only one of the M-1 transformers operates, and in a control cycle, the transformer first switches on the DC power supply through a corresponding bridge arm, and then switches off the bridge arm connected to the transformer, so that the input end of the transformer is suspended.

In an embodiment, the DC-DC converter has an individual phase-shifted full-bridge operating mode, in the individual phase-shifted full-bridge operating mode, only one of the M-1 transformers operates, and in a control period, the transformer first switches on the DC power supply to operate through a corresponding bridge arm, and then operates in a manner of short-circuiting both ends of the transformer through the corresponding bridge arm.

In another embodiment, the DC-DC converter has at least one of an individual phase-shifted full-bridge operating mode, an individual full-bridge operating mode, an alternating phase-shifted full-bridge operating mode, a dual-mode operating mode, a semi-integrated operating mode, and a fully-integrated operating mode;

in the single phase-shifted full-bridge working mode, only one transformer of the M-1 transformers works, and in a control period, the transformer is firstly connected with the direct-current power supply through a corresponding bridge arm and then works in a mode of short-circuiting two ends of the transformer through the corresponding bridge arm;

in the single full-bridge working mode, only one transformer of the M-1 transformers works, in a control period, the transformer is firstly connected with the direct-current power supply through a corresponding bridge arm, and then the bridge arm connected with the transformer is completely closed, so that the input end of the transformer is suspended;

in the alternating full-bridge working mode, in a control period, one transformer of the M-1 transformers is firstly connected with the direct-current power supply through a corresponding bridge arm, then the bridge arm connected with the transformer is completely closed, so that the input end of the transformer is suspended, the transformer works for one or more control periods in this way, and then the M-1 transformers work in a circulating mode in sequence;

in the alternative phase-shifted full-bridge working mode, in a control period, one of the transformers is firstly connected with the direct-current power supply through a corresponding bridge arm to work, then the two ends of the transformer are in short circuit work through the corresponding bridge arm, the transformer works in one or more control periods in this way, and the M-1 transformers work in a cycle mode in sequence;

in the dual-mode working mode, the M-1 transformers start a cycle from any transformer in a control period, the DC power supply is connected to work through corresponding bridge arms in sequence, and after the cycle, the last transformer enables the two ends of the last transformer to be in short-circuit follow current through the corresponding bridge arms;

in the semi-integration working mode, starting one cycle of the M-1 transformers from any transformer in one control period, sequentially connecting the direct-current power supplies to work through corresponding bridge arms, and then connecting the M-1 transformers in series to work simultaneously;

in the fully-integrated working mode, the M-1 transformers start a cycle from any transformer in a control period and are sequentially connected with the direct-current power supply through corresponding bridge arms to work;

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 set to control 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 independent phase-shifted full-bridge working mode, an independent full-bridge working mode, 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 one embodiment, in the fully integrated operation mode, according to the input voltage and the duty ratio change of each transformer, the control period is adjusted so that the maximum magnetic flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material.

In one embodiment, 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 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.

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 to be turned on/off, 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; or

Under the dual-mode working mode, the main controller controls the second bridge arm switch to be turned off firstly 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; the main controller controls the second bridge arm switch to be switched on first and controls the sixth bridge arm switch to be switched 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; or

In the semi-integration working mode or the full-integration working mode, the main controller controls the third bridge arm switch to be switched on first and controls the first bridge arm switch to be switched 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.

The invention also provides a power supply device comprising the DC-DC converter.

The DC-DC converter is provided with M bridge arm circuits, a transformer assembly and a rectification filter circuit between a power input end and a 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 invention 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 or technical solutions of the present invention, the drawings used in the embodiments or technical solutions of 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 a DC-DC converter according to the present invention;

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

FIG. 3 is a timing diagram of the DC-DC converter of the present invention operating in an alternate phase-shifted full-bridge mode;

FIG. 4 is a timing diagram of the DC-DC converter of the present invention operating in a dual mode operation mode;

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 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(s)
				V-in	Power input terminal	20	Transformer assembly
V-out	Power supply output terminal	Tx ₁ ～Tx _M-1	Transformer device
				10	Bridge arm circuit	Tx	Transformer device
11	First bridge arm circuit	Q ₁₁ ，Q ₁₂	First and second bridge arm switches
				12	Second bridge arm circuit	Q ₂₁ ，Q ₂₂	Third and fourth bridge arm switches
13	Third bridge arm circuit	Q ₃₁ ，Q ₃₂	Fifth and sixth bridge arm switch

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

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment 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, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination 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 invention 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 set to be connected with a direct current power supply;

the power output end V-out is set as an output 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 metal-oxide-semiconductor field effect transistors (MOSFET), Insulated Gate Bipolar Transistors (IGBT), gate-induced field effect transistors (GANFET), silicon field effect transistors (SiFET) 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 Tx ₁ ～Tx _M-1 The M-1 transformers Tx ₁ ～Tx _M-1 At least 2 transformers with different turn ratios are arranged in the bridge arm circuit, each 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 invention refers to electrical connection, and the invention does not limit the physical connection method of the primary coil ends of two adjacent transformers and the central points of corresponding bridge arms.

The transformer coil of the transformer assembly 20 may be configured to either step down or 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 this diode may also 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 supply into a required voltage at a secondary winding of the transformer assembly 20, and the required voltage is rectified and filtered by the rectification filter circuit 30 and then output to the power output terminal; wherein M is more than or equal to 3.

The DC-DC converter is provided with M bridge arm circuits 10, a transformer assembly 20 and a rectification filter circuit 30 between a power input end V-in and a 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 invention reduces the resistive loss, especially the follow current loss, of the bridge arm circuit and the transformer; further reducing the size of the radiator and being beneficial to energy conservation and emission reduction.

The state of two adjacent transformers is changed simultaneously by changing the state of the switches of the bridge arm circuit shared by the two adjacent transformers. Referring to fig. 1, in an embodiment, in an initial state, Q11 is turned on, Q12 is turned off, Q21 is turned off, Q22 is turned on, Q31 is turned off, and Q32 is turned on, in an ideal case, a voltage across Tx1 is the dc power voltage, and a voltage across Tx2 is zero. Without changing the state of Q11 and Q12, Q22 is turned off and Q21 is turned on after a dead time. Ideally, the voltage across Tx1 becomes zero and the voltage across Tx2 becomes the dc supply voltage.

When one of the M-1 transformers with at least one suspended end works in a switching mode, a lower tube is connected with a bridge arm circuit with a magnetizing current flowing out of two bridge arm central points connected with a primary coil connecting end, and an upper tube is connected with a bridge arm circuit with a magnetizing current flowing in of the bridge arm central points, so that the switching loss of the bridge arm circuit is minimum. Referring to fig. 1, in an embodiment, in an initial state, Q11 is turned off, Q12 is turned off, and a magnetization current of Tx1 flows from a point V1 and flows from a point V2. Since the associated Q11 and Q12 at point V1 are both off, the point V1 is in a floating state, and the voltage at point V1 is continuously reduced as the Tx1 magnetizing current is discharged. As the voltage at point V1 decreases, the switching losses due to turning on Q12 decrease.

When one of the M-1 transformers with at least one suspended end works in a switching mode, a lower tube is connected with a bridge arm circuit with a magnetizing current flowing out from the center point of two bridge arms connected with the connecting end of a primary coil, and an upper tube is connected with the bridge arm circuit with the magnetizing current flowing in from the center point of the bridge arm, so that the switching loss of the bridge arm circuit is minimum; and the other transformer which is connected with the direct current power supply to work keeps the switching state of the bridge arm unchanged and continues to work, so that the two transformers are connected with the direct current power supply to work simultaneously. Referring to fig. 1, in an embodiment, in an initial state, Q11 is turned off, Q12 is turned off, Q21 is turned on, Q22 is turned off, Q31 is turned off, Q32 is turned on, and Tx2 turns on the dc power supply to operate. The magnetization current of Tx1 flows out from point V1 and into point V2. Since the associated Q11 and Q12 at point V1 are both off, the point V1 is in a floating state, and the voltage at point V1 is continuously reduced as the Tx1 magnetizing current is discharged. As the voltage at point V1 decreases, the switching losses due to turning on Q12 decrease. After Q12 is turned on, transformers Tx1 and Tx2 operate simultaneously.

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 _max The 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 Tx ₁ And Tx ₂ The 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 Tx ₁ With the equivalent cross-sectional area of the new transformer core being maintained constant, i.e. Ae ₁ And (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 Tx ₁ The primary coil and the secondary coil have the turns kN and k respectively, and the resistance is reduced by half compared with a full-bridge transformer.

Three-bridge transformer Tx ₂ Using sum transformer Tx ₁ The 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 balance ₁ Medium maximum magnetic flux B _1max The calculation formula of (2) is as follows:

wherein VBUS is the DC supply voltage, D ₁ For transformer Tx ₁ T is the switching period of the three-bridge DC-DC converter, kN is the transformer Tx ₁ Number of turns of primary winding, Ae and Ae ₁ For transformers Tx and Tx ₁ The equivalent cross-sectional area of (a).

When in use

When, B _1max ＝B _max Three-bridge transformer Tx ₁ Three-bridge transformer Tx, which is kept in agreement with the maximum flux of the full-bridge transformer Tx ₁ Normal operation can be maintained.

Considering the case where the steady-state inductor current is greater than zero, when D is small, Tx ₂ Only need to be at Tx ₁ After working D ₂ Duty ratio of D ₂ ＝p(D-D ₁ ) And satisfy D ₁ +D ₂ Less 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 present ₁ +D ₂ When 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 bridge ₁ Will be greater than

D ₂ ＝1-D ₁ Whereby a transformer Tx appears ₁ And Tx ₂ The 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 Tx ₁ The primary winding resistance of (a) is half of that of the full-bridge transformer Tx. Because the inductive current and the turn ratio are equal to those of a full-bridge transformer when the transformer works independentlyAs well as the primary current. 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 Tx ₂ The 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 Tx ² And (4) doubling. Since the three-bridge converter and the full-bridge converter have the same inductor current, the three-bridge transformer Tx ₂ Is p times that of the full-bridge transformer Tx, so that the three-bridge transformer Tx ₂ With 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 Tx ₁ And Tx ₂ Working simultaneously, Tx ₁ And Tx ₂ The 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

Tx ₁ And Tx ₂ The 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 Tx ₁ And Tx ₂ The secondary winding resistance of (2) is half of the secondary winding resistance of the full-bridge transformer Tx. If Tx ₁ And Tx ₂ The transformer works independently, and the respective secondary instantaneous loss is half of that of the full-bridge transformer. If Tx ₁ And Tx ₂ Working simultaneously, Tx ₁ And Tx ₂ The 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,

D ₂ ＝1-D ₁

N ₁ ＝N

N ₂ ＝pN

wherein VBUS is the DC supply voltage, VOUT is the output power supply voltage, N ₁ And N ₂ Transformers Tx, respectively ₁ And Tx ₂ Primary side to secondary side winding turns ratio of D ₁ And D ₂ For transformer Tx ₁ And Tx ₂ The 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 adopted ₁ And Tx ₂ The 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, a transformer Tx of a three-bridge DC-DC converter of the present invention ₁ The number of turns of the primary coil can be kept the same as that of the transformer of the full-bridge DC-DC converterAnd the number of turns of the secondary side coil is 2kN and 2k respectively, and a magnetic core with half of the sectional area, namely Ae can be selected ₁ 0.5 Ae. Considering the condition of positive and negative balance of magnetic flux, the transformer Tx of the DC-DC converter with the three-bridge framework of the invention ₁ Maximum magnetic flux B of _1max The calculation formula of (2) is as follows:

wherein VBUS is the DC supply voltage, D ₁ For transformer Tx ₁ T is the switching period of the three-bridge DC-DC converter, 2kN is the transformer Tx ₁ Number of turns of primary winding, Ae and Ae ₁ For transformers Tx and Tx ₁ The 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 transformer ₁ The 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 example ₂ Reference 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 Q ₁₁ And a second bridge arm switch Q ₁₂ And a third bridge arm switch Q ₂₁ And a fourth bridge arm switch Q ₂₂ And a fifth bridge arm switch Q ₃₁ And a sixth arm switch Q ₃₂ (ii) a Wherein,

the first bridge arm switch Q ₁₁ And said second leg switch Q ₁₂ The first bridge arm circuit 11 is formed by series connection; the third bridge arm switch Q ₂₁ And said fourth leg switch Q ₂₂ The second bridge arm circuit 12 is formed by series connection; the fifth bridge arm switch Q ₃₁ And said sixth leg switch Q ₃₂ The 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 Tx ₁ And Tx ₂ The transformer Tx ₁ One 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 Tx ₁ The 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 Tx ₂ One 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 Tx ₂ The 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 signal, and each bridge arm switch can be switched on when receiving the driving signal of the high level and switched on when receiving the driving signal of the low levelIs turned off when the driving signal is turned 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 present embodiment, it is explained that each bridge arm switch receives a high-level driving signal to be turned on, and is turned off when receiving a low-level driving signal, when each bridge arm switching tube is turned on/off, the primary coil and the connected dc power supply form a current loop through the switched bridge arm switching tube, so that the current of the connected dc power supply flows through the primary coil, thereby coupling the energy of the electric energy to the secondary coil of the transformer assembly 20, and then the energy is rectified and filtered by the rectifying and filtering circuit 30 to be converted into a power supply, and then the power supply is output to the power load, thereby realizing the conversion and isolated output of the dc power supply. 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 _M1 And said M2 bridge arm switch Q _M2 And the M bridge arm circuit 1M is formed by series connection.

Referring to fig. 1, fig. 2 and fig. 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 having a minimum current greater than zero.

And under the alternative phase-shifted full-bridge working mode, the primary sides of the M-1 transformers sequentially work for one or more control cycles by the direct-current power supply voltage and zero voltage.

During the first part of a control period, one primary side voltage of the transformer is the direct current power supply voltage, and during the later part of the control period, the primary side voltage of the transformer is zero. The transformer operates in this manner for one or more cycles. And M-1 transformers circulate in sequence.

In the alternative phase-shifted full-bridge working mode, in a control period, one of the transformers is firstly connected with the direct-current power supply through the corresponding bridge arm to work, then the two ends of the transformer are in short circuit work through the corresponding bridge arm, the transformer works in one or more control periods in this way, and M-1 transformers work in a cycle mode in sequence.

time t0 fourth leg switch Q before time t0 ₂₂ And a sixth arm switch Q ₃₂ And the other bridge arm switches are in an on state and in a stop state. When time t0 comes, fourth arm switch Q ₂₂ When 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 Q ₂₁ Soft switching on. At this time, the transformer Tx ₂ The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

At time t2, sixth leg switch Q ₃₂ And 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 Q ₃₁ Soft switching on. Transformer Tx ₂ Third arm switch Q ₂₁ And a fifth leg switch Q ₃₁ The freewheeling state is initiated.

time t4, third arm switch Q ₂₁ When 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 Q ₂₂ Soft switching on. At this time, the transformer Tx ₂ The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

At time t6, fifth leg switch Q ₃₁ When the bridge is turned off, the bridge arm center point V3 voltage of the third bridge arm circuit 13 starts to decrease.

Transformer Tx between time t6 to time t7 ₂ Fourth leg switch Q ₂₂ And a sixth arm switch Q ₃₂ During freewheeling, the sixth arm is openOff Q ₃₂ The 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 Q ₁₂ Soft switching on.

Fourth leg switch Q at time t8 ₂₂ When 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 bridge arm central point V2 voltage of the second bridge arm circuit 12 reaches the highest point, the third bridge arm switch Q ₂₁ Soft switching on. At this time, the transformer Tx ₁ The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

Second leg switch Q at time t10 ₁₂ And is turned off, the bridge arm center point V1 of first bridge arm circuit 11 begins to rise in voltage.

At the moment t11, when the bridge arm central point V1 voltage of the first bridge arm circuit 11 reaches the highest point, the first bridge arm switch Q ₁₁ Soft switching on. Transformer Tx ₁ Third arm switch Q ₂₁ And a first leg switch Q ₁₁ And entering a freewheeling state.

time t12, third arm switch Q ₂₁ When 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 Q ₂₂ Soft switching on. At this time, the transformer Tx ₁ The primary coil couples the electric energy to the secondary coil so as to output energy outwards.

time t14 first leg switch Q ₁₁ And 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 t15 ₁ Second leg switch Q ₁₂ And a fourth leg switch Q ₂₂ Second arm switch Q during freewheeling ₁₂ The synchronous rectification may be turned on or off. If it is openedBefore time t0, Q ₁₂ A shutdown is required.

At the time t15, the bridge arm center point V3 of the third bridge arm circuit 13 automatically reaches the lowest voltage due to the influence of the bridge arm center point V2 voltage of the second bridge arm circuit 12 and the bridge arm center point V1 voltage of the first bridge arm circuit 11. Sixth bridge arm switch Q ₃₂ Soft switching on.

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

If satisfied, acts on the transformer Tx ₂ Is longer than the transformer Tx ₁ And when the residual magnetism is reset for time, the transformer can be automatically reset by alternative work. Without the intervention of any other method (such as dc blocking capacitors Cb1, Cb2, current sampling, etc.). Suppose transformer Tx ₁ Time product change of forward working voltage to VT ₁ Time product of negative working voltage is changed to VT ₂ The voltage-time product of the remanence is then (VT) ₁ -VT ₂ ) Voltage-time product of remanence (VT) in positive and negative symmetric driving ₁ -VT ₂ ) Time product variation VT with respect to forward operating voltage ₁ Or negative working voltage time product change VT ₂ Is a very small value. Transformer Tx ₂ When working in positive or negative direction, the transformer Tx can be used for more than a reasonable time ₁ Is reset, so that the transformer Tx ₁ Can always be reset. Transformer Tx for the same reason ₂ Will also be transformed by the transformer Tx ₁ And 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) ₂₁ Fourth leg switch Q ₂₂ ) In operation, (first leg switch Q) ₁₁ Second leg switch Q ₁₂ ) Or (fifth arm switch Q) ₃₁ The sixth arm switch Q ₃₂ ) 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 Q ₁₂ First, the switch is turned off to control the fifth bridge arm switch Q ₃₁ Then opening; controlling the first bridge arm switch Q ₁₁ First, the sixth bridge arm switch Q is controlled to be turned off ₃₂ Then opening;

the main controller controls the second bridge arm switch Q ₁₂ Firstly, the sixth bridge arm switch Q is controlled to be switched on ₃₂ Then the power is turned off; controlling the first bridge arm switch Q ₁₁ Firstly, the fifth bridge arm switch Q is controlled to be switched on ₃₁ And 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.

In the dual-mode 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 st transformer continues current with zero voltage. The transformers of this example are counted from right to left, and the 1 st transformer is the illustrated transformer Tx ₂ The 2 nd transformer is the illustrated transformer Tx ₁ 。

And under the dual-mode working mode, when the last transformer is switched to work, the last two transformers are simultaneously connected with the direct-current power supply to work.

In the dual-mode working mode, the M-1 transformers start a cycle from any transformer in a control period, the DC power supply is connected to work through corresponding bridge arms in sequence, and after the cycle, the last transformer enables the two ends of the last transformer to be in short-circuit follow current through the corresponding bridge arms.

Second leg switch Q at time t0 ₁₂ And a fourth leg switch Q ₂₂ When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to increase in voltage.

time t 1: third bridge arm switch Q in response to bridge arm center point V2 voltage of second bridge arm circuit 12 peaking ₂₁ Open, transformer Tx ₂ The secondary coil outputs energy outwards after rectification.

time t 2: second bridge arm switch Q ₁₂ Open, transformer Tx ₁ The secondary coil outputs energy outwards after rectification.

time t 3: sixth bridge arm switch Q ₃₂ And (6) turning off. Sixth bridge arm switch Q ₃₂ After the switch-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.

time t 4: second bridge arm switch Q ₁₂ And (6) turning off.

time t 5: after passing through a dead zone, the first bridge arm switch Q ₁₁ And a fifth leg switch Q ₃₁ And (4) opening. Transformer Tx ₁ First leg switch Q11 and third leg switch Q21 enter a freewheeling state.

time t 6: first bridge arm switch Q ₁₁ And a third arm switch Q ₂₁ When the leakage inductance resonance starts, the bridge arm center point V2 of second bridge arm circuit 12 starts to decrease in voltage.

time t 7: when the bridge arm center point V2 voltage of the second bridge arm circuit 12 reaches the lowest point, the fourth bridge arm switch Q ₂₂ Open, transformer Tx ₂ The secondary coil outputs energy outwards after rectification.

time t 8: first bridge arm switch Q ₁₁ Open, transformer Tx ₁ The secondary coil outputs energy outwards after rectification.

time t 9: fifth bridge arm switch Q ₃₁ And (4) turning off. Fifth bridge arm switch Q ₃₁ After 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 t 10: first bridge arm switch Q ₁₁ And (6) turning off.

time t 11: after passing through a dead zone, the second leg switch Q ₁₂ And a sixth arm switch Q ₃₂ And (4) opening. Transformer Tx ₁ Second leg switch Q ₁₂ And a fourth leg switch Q ₂₂ And 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 mode ₂₁ Firstly, the first bridge arm switch Q is switched on and controlled ₁₁ Then the power is cut off; controlling the fourth leg switch Q ₂₂ Firstly, the second bridge arm switch Q is controlled to be switched on ₁₂ Then the power is turned off;

the main controller controls the second bridge arm switch Q ₁₂ Firstly, the sixth bridge arm switch Q is controlled to be switched on ₃₂ Then the power is turned off; control the first bridge arm switch Q ₁₁ Firstly, the fifth bridge arm switch Q is controlled to be switched on ₃₁ Then the power is turned off;

the main controller controls the fifth bridge arm switch Q ₃₁ Firstly, the fourth bridge arm switch Q is controlled to be switched on ₂₂ Then switching on to control the sixth bridge arm switch Q ₃₂ Firstly, the third bridge arm switch Q is controlled to be switched on ₂₁ Then 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.

In the 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. The transformers of this example are counted from right to left, and the 1 st transformer is the illustrated transformer Tx ₂ The 2 nd transformer is the illustrated transformer Tx ₁ 。

And under the semi-integration working mode, when the last transformer is switched to work, the last two transformers are simultaneously connected with the direct current power supply to work.

In the semi-integration working mode, the M-1 transformers start a cycle from any transformer in a control period, are sequentially connected with the direct-current power supply through corresponding bridge arms to work, and then are connected in series to work simultaneously.

time t 0: third arm switch Q ₂₁ Opening, Tx ₂ After rectification, the energy is output separately.

time t 1: first bridge arm switch Q ₁₁ And is turned off, and the magnetizing current discharges arm center point V1 of first arm circuit 11.

time t 2: second bridge arm switch Q ₁₂ Is turned on, at this time, the transformer Tx ₁ And energy is output to the outside independently after rectification.

time t 3: sixth bridge arm switch Q ₃₂ And (6) turning off. Tx is utilized between t3-t4 ₂ Residual 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 reduced ₃₁ Loss at turn-on.

time t 4: third arm switch Q ₂₁ And (6) turning off. Fifth bridge arm switch Q ₃₁ And (4) opening. Transformer Tx between t4-t5 ₁ And a transformer Tx ₂ After rectification, the energy is output outwards together.

time t 5: fourth bridge arm switch Q ₂₂ And (4) opening. At this time, the transformer Tx ₂ After rectification, the energy is output separately.

time t 6: second bridge arm switch Q ₁₂ Off, the magnetizing current charges the leg center point V1 of first leg circuit 11.

time t 7: first bridge arm switch Q ₁₁ Open, transformer Tx ₁ After rectification, the energy is output separately.

time t 8: fifth bridge arm switch Q ₃₁ And (6) turning off. Maximum utilization of transformer Tx in time period t8-t9 ₂ The 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 reduced ₃₂ Loss at turn-on.

time t 9: fourth bridge arm switch Q ₂₂ And (6) turning off. Sixth bridge arm switch Q ₃₂ And (4) opening. Transformer Tx between t9-t0 ₁ And a transformer Tx ₂ After rectification, the energy is output outwards together.

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

In this mode, Tx ₂ ->Tx ₁ ->(Tx ₁ And Tx ₂ Working 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, the DC-DC converter has a fully integrated operation mode, and fig. 6 is a timing chart of driving signals received by each bridge arm switch in the fully integrated operation mode. The following analysis is based on the case where the inductance L1 minimum current is greater than zero.

And under the full integration working mode, the 1 st to the M-1 st transformers work with the direct-current power supply voltage in sequence in one control period.

And under the full-integration working mode, starting one cycle of the M-1 transformers from any transformer in one control period, and sequentially connecting the direct-current power supplies to work through corresponding bridge arms.

And under the fully-integrated working mode, adjusting a control period according to the input voltage and the change of the duty ratio of each transformer, so that the maximum magnetic flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material. As the product of the input voltage and the duty ratio increases, the control period is reduced so that the maximum magnetic flux of the magnetic material does not exceed an allowable value, preventing magnetic saturation from occurring.

And under the fully integrated working mode, when the last transformer is switched to work, the last two transformers are simultaneously connected with the direct-current power supply to work.

time t 0: third bridge arm switch Q in response to second bridge arm circuit 12 having bridge arm center point V2 voltage rising to the highest point ₂₁ And (4) opening. Transformer Tx ₂ Through a processAnd the energy is output outwards independently after flowing.

time t 1: first bridge arm switch Q ₁₁ Off, the magnetizing current discharges leg center point V1 of first leg circuit 11.

time t 2: second bridge arm switch Q ₁₂ Open, transformer Tx ₁ After rectification, the energy is output separately.

time t 3: sixth bridge arm switch Q ₃₂ And (6) turning off. Maximum Tx utilization at time t3-t4 ₂ Residual 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 reduced ₃₁ Loss at turn-on. Fifth bridge arm switch Q ₃₁ Turned on at some time between times t3-t 4.

time t 4: third arm switch Q ₂₁ And (6) turning off. Resonance begins and the bridge leg center point V2 voltage of second bridge leg circuit 12 begins to decrease.

time t 5: the bridge arm center point V2 voltage of the second bridge arm circuit 12 drops to the lowest point, and the fourth bridge arm switch Q ₂₂ And (4) opening. Transformer Tx ₂ And energy is output to the outside independently after rectification.

time t 8: fifth leg switch Q ₃₁ And (6) turning off. Maximum utilization of transformer Tx at time t8-t9 ₂ The 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 reduced ₃₂ Loss at turn-on. Sixth bridge arm switch Q ₃₂ Turned on at some time between times t8-t 9.

time t 9: fourth bridge arm switch Q ₂₂ Off, resonance begins and the leg center point V2 of second leg circuit 12 begins to rise in voltage.

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

In this mode, the transformer Tx ₂ And a transformer Tx ₁ The 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 Tx ₁ ～Tx _M-1 More 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 Tx ₁ ～Tx _M-1 Matched with M bridge arm circuits 10, M-1 transformers Tx ₁ ～Tx _M-1 And 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. In 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-1 And (4) freewheeling in a zero-voltage mode, and starting to work when the No. 1 transformer is connected with the No. M-1 transformer in a seamless mode in the next control period. 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 Tx ₁ ～Tx _M-1 And 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, under the M-bridge structure, M is greater than or equal to three, the DC-DC converter may further be provided with blocking capacitors, and each blocking capacitorThe DC blocking capacitor is connected with a primary coil of the transformer needing magnetic balance in series, and the number of the DC blocking capacitors can 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 11 ₁ May also be provided between the bridge arm center point V2 of second bridge arm circuit 12 and transformer Tx ₁ And the other of the primary coil connection terminals. In the same way, at the transformer Tx ₂ Between one of said primary coil connection terminals and the leg center point V2 of the second leg circuit 12 or at the transformer Tx ₂ A 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 DC-DC converter of the present invention is not limited to the above-mentioned working modes and the specific working modes of the working modes, for example, the DC-DC converter of the present invention has at least one mode of an individual phase-shifted full-bridge working mode, an individual full-bridge working mode, 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 single phase-shifted full-bridge working mode, only one of the M-1 transformers works, and in a control period, the transformer is firstly switched on to work by the direct-current power supply through a corresponding bridge arm and then works in a mode of short-circuiting two ends of the transformer through the corresponding bridge arm;

in the alternative full-bridge working mode, in a control period, one transformer of the M-1 transformers is firstly connected with the direct-current power supply through a corresponding bridge arm, then the bridge arm connected with the transformer is completely closed, so that the input end of the transformer is suspended, the transformer works for one or more control periods in this way, and the M-1 transformers sequentially work in a circulating mode;

in the semi-integration working mode, starting a cycle of the M-1 transformers from any transformer in a control period, sequentially connecting the direct-current power supplies to work through corresponding bridge arms, and simultaneously connecting the M-1 transformers in series to work after the cycle;

In this embodiment:

and in a dual-mode working mode, or in a semi-integrated working mode, or in a fully-integrated working mode, when the last transformer is switched to work, the last two transformers are simultaneously connected with the direct-current power supply to work.

And under the fully-integrated working mode, adjusting a control period according to the input voltage and the change of the duty ratio of each transformer, so that the maximum magnetic flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material.

The switching between any two modes has the hysteresis of the change of the equivalent full-bridge duty cycle as the equivalent full-bridge duty cycle changes. Wherein,

the equivalent full-bridge duty ratio of the alternating phase-shifted full-bridge working mode switched into the half-integrated working mode is larger than that of the alternating phase-shifted full-bridge working mode switched from the half-integrated working mode;

the equivalent full-bridge duty ratio switched from the dual-mode working mode to the half-integrated working mode is larger than that switched from the half-integrated working mode to the dual-mode working mode;

the equivalent full-bridge duty cycle for switching from the semi-integrated operating mode to the fully integrated operating mode is greater than the equivalent full-bridge duty cycle for switching from the integrated operating mode to the semi-integrated operating mode.

The detailed structure of the DC-DC converter can refer to the above embodiments, and is not described herein; it can be understood that, since the power supply apparatus of the present invention uses the DC-DC converter, the embodiments of the power supply apparatus of the present invention include all technical solutions of all embodiments of the DC-DC converter, and the achieved technical effects are also completely the same, and are not described herein again.

The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents made by the contents of the present specification and drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

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

the power supply output end is arranged to output a power supply;

the transformer assembly comprises M-1 transformers, at least 2 transformers with different turn ratios are arranged in the M-1 transformers, each 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;

2. The DC-DC converter of claim 1, wherein the states of two adjacent transformers are changed simultaneously by changing the state of a switch of a bridge arm circuit shared by the two adjacent transformers.

3. The DC-DC converter according to claim 1, wherein when at least one of M-1 transformers has a suspended end, the bridge arm circuit with the magnetizing current flowing out from the center point of the two bridge arms connected to the connection end of the primary coil is turned on the lower tube, and the bridge arm circuit with the magnetizing current flowing into the center point of the bridge arm is turned on the upper tube, so that the switching loss of the bridge arm circuit is minimized.

4. The DC-DC converter according to claim 1, wherein when one of the M-1 transformers has at least one end suspended, the bridge arm circuit from which the magnetizing current flows out in the center point of the two bridge arms connected to the connection end of the primary coil is turned on with the lower tube, and the bridge arm circuit from which the magnetizing current flows in the center point of the bridge arm is turned on with the upper tube, so that the switching loss of the bridge arm circuit is minimized; and the other transformer which is connected with the direct current power supply to work keeps the switching state of the bridge arm unchanged and continues to work, so that the two transformers are connected with the direct current power supply to work simultaneously.

5. The DC-DC converter according to claim 1, wherein the DC-DC converter has an alternating phase-shifted full-bridge mode of operation,

6. The DC-DC converter according to claim 1, wherein the DC-DC converter has an alternating phase-shifted full-bridge mode of operation,

7. The DC-DC converter according to claim 1, wherein the DC-DC converter has a dual mode operation mode,

in the dual-mode 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 st transformer continues current with zero voltage.

8. The DC-DC converter according to claim 7, wherein in the dual mode operation mode, when switching to the last transformer, the last two transformers are simultaneously switched on to operate the DC power source.

9. The DC-DC converter according to claim 1, wherein the DC-DC converter has a dual mode operation mode,

10. The DC-DC converter of claim 9, wherein in the dual mode operation mode, when switching to the last transformer, the last two transformers are simultaneously switched on the DC power supply to operate.

11. The DC-DC converter according to claim 1, wherein the DC-DC converter has a semi-integral mode of operation,

in the 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.

12. A DC-DC converter according to claim 11, wherein in the semi-integral mode of operation, the last two transformers are simultaneously switched on the DC power supply to operate when switching to the last transformer.

13. The DC-DC converter according to claim 1, wherein the DC-DC converter has a semi-integral mode of operation,

in the semi-integration working mode, the M-1 transformers start a cycle from any transformer in a control period, the DC power supply is connected to work sequentially through corresponding bridge arms, and the M-1 transformers are connected in series to work simultaneously after the cycle.

14. A DC-DC converter according to claim 13, wherein in the semi-integral mode of operation, the last two transformers are switched on the DC power supply to operate simultaneously when switching to the last transformer.

15. The DC-DC converter according to claim 1, wherein the DC-DC converter has a fully integrated mode of operation,

16. A DC-DC converter according to claim 15, wherein in the fully integrated mode of operation, the control period is adjusted according to the input voltage and the variation of the duty cycle of each transformer such that the maximum flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material.

17. A DC-DC converter according to claim 15, wherein in the fully integrated mode of operation, when the last transformer is switched to operate, the last two transformers are simultaneously switched on to operate from the DC power source.

18. The DC-DC converter according to claim 1, wherein the DC-DC converter has a fully integrated mode of operation,

19. A DC-DC converter according to claim 18, wherein in the fully integrated mode of operation, the control period is adjusted according to the input voltage and the variation of the duty cycle of each transformer such that the maximum flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material.

20. A DC-DC converter according to claim 18, wherein in the fully integrated mode of operation, the last two transformers are simultaneously switched on to operate the DC power supply when switching to operate the last transformer.

21. 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;

under an alternative phase-shifted full-bridge working mode, the primary sides of the M-1 transformers sequentially work for one or more control cycles by the direct-current power supply voltage and zero voltage;

22. A DC-DC converter according to claim 21, wherein in a dual mode operation mode, or in a semi-integrated operation mode, or in a fully integrated operation mode, the last two transformers are switched on the DC power supply to operate simultaneously when switching to the last transformer.

23. A DC-DC converter according to claim 21, wherein in the fully integrated mode of operation, the control period is adjusted according to the input voltage and the variation of the duty cycle of each transformer such that the maximum flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material.

24. A DC-DC converter according to claim 21, wherein the switching between any two modes has a hysteresis of the equivalent full-bridge duty cycle variation as the equivalent full-bridge duty cycle varies.

25. The DC-DC converter according to claim 1, wherein the DC-DC converter has an alternating full-bridge mode of operation,

in the alternative full-bridge working mode, in a control period, one transformer of the M-1 transformers is firstly connected with the direct-current power supply through a corresponding bridge arm to work, then the bridge arm connected with the transformer is completely closed, so that the input end of the transformer is suspended, the transformer works in one or more control periods in this way, and the M-1 transformers work in a cycle mode in sequence.

26. The DC-DC converter according to claim 1, wherein the DC-DC converter has a single full-bridge mode of operation,

in the independent full-bridge working mode, only one transformer of the M-1 transformers works, in a control period, the transformer is firstly connected with the direct-current power supply through a corresponding bridge arm to work, and then the bridge arm connected with the transformer is completely closed to enable the input end of the transformer to suspend.

27. The DC-DC converter according to claim 1, wherein the DC-DC converter has a single phase-shifted full-bridge mode of operation,

in the single phase-shifted full-bridge working mode, only one of the M-1 transformers works, and in a control period, the transformer is firstly switched on the direct-current power supply to work through a corresponding bridge arm and then works in a mode of short-circuiting two ends of the transformer through the corresponding bridge arm.

28. The DC-DC converter of claim 1, wherein the DC-DC converter has at least one of an individual phase-shifted full-bridge operating mode, an individual full-bridge operating mode, an alternating phase-shifted full-bridge operating mode, a dual-mode operating mode, a semi-integrated operating mode, and a fully integrated operating mode;

in the single phase-shifted full-bridge working mode, only one of the M-1 transformers works, and in a control period, the transformer is firstly switched on the direct-current power supply to work through a corresponding bridge arm and then works in a mode of short-circuiting two ends of the transformer through the corresponding bridge arm;

in the fully-integrated working mode, starting one cycle of the M-1 transformers from any transformer in one control period, and sequentially switching on the direct-current power supply to work through corresponding bridge arms;

29. A DC-DC converter according to claim 28, wherein in a dual mode operation mode, or in a semi-integrated operation mode, or in a fully integrated operation mode, the last two transformers are switched on the DC power supply to operate simultaneously when switching to the last transformer.

30. A DC-DC converter according to claim 28, wherein in the fully integrated mode of operation, the control period is adjusted according to the input voltage and the variation of the duty cycle of each transformer such that the maximum flux of any one of the M-1 transformers does not exceed the maximum allowable value of the magnetic material.

31. A DC-DC converter according to claim 28, wherein the switching between any two modes has a hysteresis of the equivalent full-bridge duty cycle variation as the equivalent full-bridge duty cycle varies.

32. The DC-DC converter of claim 28, wherein when M is 3, 3 of the leg circuits comprise a first leg switch, a second leg switch, a third leg switch, a fourth leg switch, a fifth leg switch, and a sixth leg switch; wherein,

33. The DC-DC converter of claim 32, wherein in the alternating phase-shifted full-bridge operating mode, the main controller controls 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 two bridge arm switches of the other bridge arm circuit to be turned off fully when controlling the two bridge arm switches of the second bridge arm circuit to be turned on/off.

34. The DC-DC converter of claim 32, wherein in the dual mode operating mode, the main controller controls the second leg switch to turn off first and controls the fifth leg switch to turn 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;

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.

35. The DC-DC converter of claim 32, wherein in the semi-integrated operating mode or the fully integrated operating mode, the main controller controls the third leg switch to turn on first and then turn off the first leg switch; 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.

36. A power supply apparatus comprising a DC-DC converter according to any one of claims 1 to 35.