CN109921634B

CN109921634B - Train and control method and device of bidirectional DC-DC converter of train

Info

Publication number: CN109921634B
Application number: CN201711318586.6A
Authority: CN
Inventors: 邬白贺; 王兴辉; 王超
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2017-12-12
Filing date: 2017-12-12
Publication date: 2021-04-20
Anticipated expiration: 2037-12-12
Also published as: CN109921634A

Abstract

The invention discloses a train and a control method and a control device of a bidirectional DC-DC converter thereof, wherein the bidirectional DC-DC converter comprises a first conversion branch, a second conversion branch and a third conversion branch which are mutually connected in parallel, each conversion branch comprises an upper bridge switching tube and a lower bridge switching tube which are connected in series and is provided with a node, a standby bridge arm comprises a standby upper bridge switching tube and a standby lower bridge switching tube which are connected in series and is provided with a first node, and the first node is correspondingly connected to the node of each conversion branch through a controllable switch respectively, and the control method comprises the following steps: acquiring power to be output; judging a power interval in which the power to be output is positioned; controlling an upper bridge switching tube and a lower bridge switching tube according to the power interval, and controlling the conversion branches to work in turn when the output power is smaller than the preset power; if any one conversion branch is identified to be in fault, the standby bridge arm is controlled to replace the bridge arm in the fault conversion branch to work in turn, so that the working time of the switching tube can be shortened, and the life cycle of the bidirectional DC-DC converter is prolonged.

Description

Train and control method and device of bidirectional DC-DC converter of train

Technical Field

The present invention relates to the field of vehicle technologies, and in particular, to a control method of a bidirectional DC-DC converter, a non-transitory computer-readable storage medium, a control apparatus of a bidirectional DC-DC converter, and a train.

Background

The bidirectional DC-DC converter has been an important component in the power electronics field, and with the development of the vehicle field, the DC-DC converter has also become one of the important parts on the train. In the related art, a bidirectional DC-DC converter usually adopts three Boost topological structures, namely, the output power of the bidirectional DC-DC converter is improved in a mode that three Boost conversion branches are connected in parallel, and the total power is divided equally by the three Boost conversion branches in the working process of the bidirectional DC-DC converter. Therefore, the related art has a problem that the three Boost conversion branches work simultaneously no matter the target output power, so that circuit elements are in a working state for a long time, and the working life of the switching tube is influenced.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the art described above. Therefore, a first object of the present invention is to provide a control method for a bidirectional DC-DC converter, which can enable three conversion branches to work in turn when the output power is smaller than the preset power, and enable a backup bridge arm to work in turn instead of a failed bridge arm when any one conversion branch fails, so as to prolong the life cycle of the bidirectional DC-DC converter.

A second object of the invention is to propose a non-transitory computer-readable storage medium. A third object of the present invention is to provide a bidirectional DC-DC converter. A fourth object of the present invention is to provide a control device for a bidirectional DC-DC converter. A fifth object of the present invention is to provide a bidirectional DC-DC converter. A sixth object of the invention is to propose a train.

In order to achieve the above object, a first aspect of the present invention provides a control method for a bidirectional DC-DC converter, where the bidirectional DC-DC converter includes a first conversion branch, a second conversion branch, a third conversion branch, and a spare bridge arm, the first conversion branch, the second conversion branch, and the third conversion branch are connected in parallel, each of the first conversion branch, the second conversion branch, and the third conversion branch includes an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and have a node as a node of each conversion branch, the spare bridge arm includes a spare upper bridge switching tube and a spare lower bridge switching tube, the spare upper bridge switching tube and the spare lower bridge switching tube are connected in series and have a first node, and the first node is correspondingly connected to a node of each conversion branch through a controllable switch, the control method comprises the following steps: acquiring the power to be output of the bidirectional DC-DC converter; judging a power interval in which the power to be output is positioned, wherein the output power of the bidirectional DC-DC converter is divided into a plurality of power intervals; controlling the upper bridge switching tube and the lower bridge switching tube according to the power interval of the power to be output so as to control the first conversion branch, the second conversion branch and the third conversion branch to work in turn when the power to be output is smaller than the preset power; in the process of alternately working the first conversion branch, the second conversion branch and the third conversion branch, if any one conversion branch of the first conversion branch, the second conversion branch and the third conversion branch is identified to have a fault, a controllable switch between the first node and the node of the fault conversion branch is controlled to be closed, so that the standby bridge arm replaces the bridge arm in the fault conversion branch to alternately work.

According to the control method of the bidirectional DC-DC converter provided by the embodiment of the invention, the bidirectional DC-DC converter comprises a first conversion branch, a second conversion branch, a third conversion branch and a standby bridge arm, wherein the first conversion branch, the second conversion branch and the third conversion branch are mutually connected in parallel, each conversion branch of the first conversion branch, the second conversion branch and the third conversion branch comprises an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and have a node as the node of each conversion branch, the standby bridge arm comprises a standby upper bridge switching tube and a standby lower bridge switching tube, the standby upper bridge switching tube and the standby lower bridge switching tube are connected in series and have a first node, the first nodes are respectively correspondingly connected to the node of each conversion branch through controllable switches, the control method obtains the power to be output of the bidirectional DC-DC converter, judging a power interval in which power to be output is positioned, controlling an upper bridge switching tube and a lower bridge switching tube according to the power interval in which the power to be output is positioned so as to control a first conversion branch, a second conversion branch and a third conversion branch to work in turn when the power to be output is smaller than preset power, and controlling a controllable switch between a first node and a node of a fault conversion branch to be closed if any one of the first conversion branch, the second conversion branch and the third conversion branch is identified to have a fault in the process of working in turn of the first conversion branch, the second conversion branch and the third conversion branch so as to enable a standby bridge arm to replace a bridge arm in the fault conversion branch to work in turn. Therefore, the control method provided by the embodiment of the invention can effectively reduce the working time of the switching tube, prolong the working life of the switching tube in the conversion branch, and access the standby bridge arm to work in turn when any conversion branch of the bidirectional DC-DC converter fails, so that the life cycle of the bidirectional DC-DC converter can be prolonged.

To achieve the above object, a non-transitory computer-readable storage medium is provided in an embodiment of a second aspect of the present invention, on which a computer program is stored, and the computer program realizes the control method of the bidirectional DC-DC converter when being executed by a processor.

According to the non-transitory computer readable storage medium provided by the embodiment of the invention, by realizing the control method of the bidirectional DC-DC converter, the working time of the switching tube can be effectively reduced, the working life of the switching tube in the conversion branch is prolonged, when any one conversion branch of the bidirectional DC-DC converter breaks down, the standby bridge arm is connected to work in turn, and further the life cycle of the bidirectional DC-DC converter can be prolonged.

In order to achieve the above object, a bidirectional DC-DC converter according to an embodiment of a third aspect of the present invention includes a first converting branch, a second converting branch, and a third converting branch, where the first converting branch, the second converting branch, and the third converting branch are connected in parallel, each of the first converting branch, the second converting branch, and the third converting branch includes an upper switching tube and a lower switching tube, the bidirectional DC-DC converter further includes a memory, a processor, and a control program of the bidirectional DC-DC converter stored in the memory and operable on the processor, and the control program of the bidirectional DC-DC converter, when executed by the processor, implements a control method of the bidirectional DC-DC converter.

According to the bidirectional DC-DC converter provided by the embodiment of the invention, by realizing the control method of the bidirectional DC-DC converter, the working time of the switching tube can be effectively reduced, the working life of the switching tube in the conversion branch is prolonged, when any one conversion branch of the bidirectional DC-DC converter breaks down, the standby bridge arm is connected to work in turn, and further the life cycle of the bidirectional DC-DC converter can be prolonged.

In order to achieve the above object, a control device for a bidirectional DC-DC converter according to a fourth aspect of the present invention includes a first conversion branch, a second conversion branch, a third conversion branch, and a spare bridge arm, where the first conversion branch, the second conversion branch, and the third conversion branch are connected in parallel, each of the first conversion branch, the second conversion branch, and the third conversion branch includes an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and have a node as a node of each conversion branch, the spare bridge arm includes a spare upper bridge switching tube and a spare lower bridge switching tube, the spare upper bridge switching tube and the spare lower bridge switching tube are connected in series and have a first node, and the first node is correspondingly connected to a node of each conversion branch through a controllable switch, the control device includes: the acquisition module is used for acquiring the power to be output of the bidirectional DC-DC converter; the judging module is used for judging a power interval where the power to be output is located, wherein the output power of the bidirectional DC-DC converter is divided into a plurality of power intervals; and the control module is used for controlling the upper bridge switching tube and the lower bridge switching tube according to the power interval where the power to be output is located so as to control the first conversion branch, the second conversion branch and the third conversion branch to work in turn when the power to be output is smaller than the preset power, wherein in the process of working in turn of the first conversion branch, the second conversion branch and the third conversion branch, if any one of the first conversion branch, the second conversion branch and the third conversion branch is identified to have a fault, a controllable switch between a first node and a node of the fault conversion branch is controlled to be closed so that the standby bridge arm replaces a bridge arm in the fault conversion branch to work in turn.

The control device of the bidirectional DC-DC converter comprises a first conversion branch, a second conversion branch, a third conversion branch and a standby bridge arm, wherein the first conversion branch, the second conversion branch and the third conversion branch are connected in parallel, each conversion branch comprises an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and provided with a node to serve as a node of each conversion branch, the standby bridge arm comprises a standby upper bridge switching tube and a standby lower bridge switching tube, the standby upper bridge switching tube and the standby lower bridge switching tube are connected in series and provided with a first node, the first nodes are respectively connected to the nodes of each conversion branch through controllable switches, and an acquisition module acquires power to be output of the bidirectional DC-DC converter, the judging module judges a power interval where power to be output is located, the control module controls the upper bridge switching tube and the lower bridge switching tube according to the power interval where the power to be output is located to control the first conversion branch, the second conversion branch and the third conversion branch to work in turn when the power to be output is smaller than preset power, and in the process of working in turn of the first conversion branch, the second conversion branch and the third conversion branch, if any one conversion branch among the first conversion branch, the second conversion branch and the third conversion branch is identified to be in fault, the controllable switch between the first node and the node of the fault conversion branch is controlled to be closed, so that a standby bridge arm replaces a bridge arm in the fault conversion branch to work in turn. Therefore, the control device provided by the embodiment of the invention can effectively reduce the working time of the switching tube, prolong the working life of the switching tube in the conversion branch, and access the standby bridge arm to work in turn when any conversion branch of the bidirectional DC-DC converter fails, so that the life cycle of the bidirectional DC-DC converter can be prolonged.

In order to achieve the above object, a bidirectional DC-DC converter according to an embodiment of a fifth aspect of the present invention includes the control device of the bidirectional DC-DC converter.

According to the bidirectional DC-DC converter provided by the embodiment of the invention, through the control device of the bidirectional DC-DC converter, the working time of the switching tube can be effectively reduced, the working life of the switching tube in the conversion branch is prolonged, when any one conversion branch of the bidirectional DC-DC converter breaks down, the standby bridge arm is connected to work in turn, and further the life cycle of the bidirectional DC-DC converter can be prolonged.

In order to achieve the above object, a sixth embodiment of the present invention provides a train, including the bidirectional DC-DC converter.

According to the train provided by the embodiment of the invention, the bidirectional DC-DC converter is utilized, the working time of the switching tube can be effectively reduced, the working life of the switching tube in the conversion branch is prolonged, when any one conversion branch of the bidirectional DC-DC converter breaks down, the standby bridge arm is connected to work in turn, and further the life cycle of the bidirectional DC-DC converter can be prolonged.

Drawings

FIG. 1 is a circuit schematic of a bi-directional DC-DC converter according to one embodiment of the present invention;

FIG. 2 is a flow chart of a method of controlling a bi-directional DC-DC converter according to an embodiment of the present invention;

FIG. 3 is a flow chart of a method of controlling a bi-directional DC-DC converter according to an embodiment of the present invention;

FIG. 4 is a block schematic diagram of a control arrangement for a bi-directional DC-DC converter according to an embodiment of the present invention;

FIG. 5 is a block schematic diagram of a bidirectional DC to DC converter according to an embodiment of the present invention;

fig. 6 is a block schematic diagram of a train according to an embodiment of the invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

A control method of a bidirectional DC-DC converter, a control device of a bidirectional DC-DC converter, and a train according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in fig. 1, a bidirectional DC-DC converter according to an embodiment of the present invention includes a first converting branch, a second converting branch and a third converting branch, the first converting branch, the second converting branch and the third converting branch are connected in parallel with each other, each of the first converting branch, the second converting branch and the third converting branch includes an upper bridge switching tube and a lower bridge switching tube, namely, the first conversion branch comprises a first upper bridge switching tube Q11 and a first lower bridge switching tube Q12, a second node J2 is arranged between the first upper bridge switching tube Q11 and the first lower bridge switching tube Q1, the second conversion branch comprises a second upper bridge switching tube Q21 and a second lower bridge switching tube Q22, a third node J3 is arranged between the second upper bridge switching tube Q21 and the second lower bridge switching tube Q22, the third conversion branch comprises a third upper bridge switching tube Q31 and a third lower bridge switching tube Q32, and a fourth node J4 is arranged between the third upper bridge switching tube Q31 and the third lower bridge switching tube Q32.

As shown in fig. 1, the bidirectional DC-DC converter further includes a first inductor L1, a second inductor L2, a third inductor L3, and a first capacitor C1, wherein one end of the first inductor L1 is connected to the second node J2, one end of the second inductor L2 is connected to the third node J3, one end of the third inductor L3 is connected to the fourth node J4, the other end of the third inductor L3 is connected to both the other end of the first inductor L1 and the other end of the second inductor L2, and the first capacitor C1 is connected to the output terminal of the bidirectional DC-DC converter.

When the bidirectional DC-DC converter works in a forward direction, the first upper bridge switching tube Q11, the second upper bridge switching tube Q21 and the third upper bridge switching tube Q31 are controlled to be switched on and off, when the first upper bridge switching tube Q11, the second upper bridge switching tube Q21 and the third upper bridge switching tube Q31 are controlled to be switched on, the first upper bridge switching tube Q11, the second upper bridge switching tube Q21 and the third upper bridge switching tube Q31 respectively charge the first inductor L1, the second inductor L2 and the third inductor L3, and when the first upper bridge switching tube Q11, the second upper bridge switching tube Q21 and the third upper bridge switching tube Q31 are controlled to be switched off, the first inductor L1, the second inductor L2 and the third inductor L3 respectively pass through the first lower bridge switching tube Q12, the second lower bridge switching tube Q22 and the third lower bridge switching tube Q32 to reduce voltage. On the contrary, when the bidirectional DC-DC converter works reversely, the first lower bridge switching tube Q12, the second lower bridge switching tube Q22 and the third lower bridge switching tube Q32 are controlled to be turned on and off, when the first lower bridge switching tube Q12, the second lower bridge switching tube Q22 and the third lower bridge switching tube Q32 are controlled to be turned on, the first lower bridge switching tube Q12, the second lower bridge switching tube Q22 and the third lower bridge switching tube Q32 are controlled to be turned on to respectively charge the first inductor L1, the second inductor L2 and the third inductor L3, and the first lower bridge switching tube Q12, the second lower bridge switching tube Q22 and the third lower bridge switching tube Q32 are controlled to be turned on, and the first inductor L1, the second inductor L2 and the third inductor L3 are respectively controlled to be turned on through the first upper bridge switching tube Q11, the second upper bridge switching tube Q21 and the third upper bridge switching tube Q31.

The bidirectional DC-DC converter further comprises a standby bridge arm, wherein the standby bridge arm comprises a standby upper bridge switching tube Q41 and a standby lower bridge switching tube Q42, the standby upper bridge switching tube Q41 and the standby lower bridge switching tube Q42 are connected in series and provided with a first node J1, and the first node J1 is correspondingly connected to nodes of each conversion branch, namely a second node J2, a third node J3 and a fourth node J4 through controllable switches.

In an embodiment of the present invention, as shown in fig. 2, the control method of the bidirectional DC-DC converter includes the following steps:

s1: and acquiring the power to be output of the bidirectional DC-DC converter.

S2: and judging a power interval in which the power to be output is positioned, wherein the output power of the bidirectional DC-DC converter is divided into a plurality of power intervals.

According to an embodiment of the present invention, the plurality of power intervals are a first power interval, a second power interval and a third power interval, the power corresponding to the second power interval is greater than the power corresponding to the first power interval, the power corresponding to the third power interval is greater than the power corresponding to the second power interval, and an upper limit value of the second power interval is a preset power. The preset power may be 200kw, specifically, the first power interval may be 0kw-100kw, the second power interval may be 100kw-200kw, and the third power interval may be 200kw-300 kw.

S3: and controlling the upper bridge switching tube and the lower bridge switching tube according to the power interval of the power to be output so as to control the first conversion branch, the second conversion branch and the third conversion branch to work in turn when the power to be output is smaller than the preset power.

According to one embodiment of the invention, when the power to be output is in the first power interval, the upper bridge switching tube and the lower bridge switching tube are controlled, so that the first conversion branch, the second conversion branch and the third conversion branch work in turn.

It should be noted that, when the power to be output is in the first power interval, the first conversion branch, the second conversion branch and the third conversion branch sequentially work in turn by controlling the upper bridge switching tube and the lower bridge switching tube. For example, when the first conversion branch circuit works, the first upper bridge switching tube and the first lower bridge switching tube of the first conversion branch circuit can be controlled to be switched on or switched off, so as to control the first conversion branch circuit to work, at the moment, the upper bridge switch tube and the lower bridge switch tube of the second conversion branch circuit and the third conversion branch circuit are both switched off, when the second conversion branch circuit is controlled to work, the second upper bridge switching tube and the second lower bridge switching tube of the second conversion branch circuit can be controlled to be switched on or switched off, to control the second conversion branch to work, at the moment, the upper bridge switch tube and the lower bridge switch tube of the first conversion branch and the third conversion branch are both switched off, and when controlling the third conversion branch circuit to work, controlling the third upper bridge switch tube and the third lower bridge switch tube of the third conversion branch circuit to be switched on or switched off, and controlling the third control branch to work, wherein the upper bridge switching tube and the lower bridge switching tube of the first conversion branch and the second conversion branch are both switched off. When the upper bridge switching tube and the lower bridge switching tube are controlled to be switched on or switched off, the upper bridge switching tube can be controlled to be switched on or switched off during forward work, and the lower bridge switching tube can be controlled to be switched on or switched off during reverse work. Specifically, the first conversion branch, the second conversion branch and the third conversion branch respectively have different flag bits when operating, wherein when the bidirectional DC-DC converter operates in a manner that the first conversion branch, the second conversion branch and the third conversion branch sequentially operate in turn each time, when the bidirectional DC-DC converter currently starts to operate, the conversion branch which operates first needs to be determined in a cyclic manner of the first conversion branch → the second conversion branch → the third conversion branch → the first conversion branch according to the flag bit of the conversion branch when the operation is finished last time.

That is, when the bidirectional DC-DC converter operates, the power interval in which the power to be output is determined after the power to be output is obtained, when the power interval in which the power to be output is located is the first power interval, the flag bit of the last conversion branch of the bidirectional DC-DC converter when the operation is ended is obtained, and the conversion branch of the last operation is determined according to the flag bit of the conversion branch when the operation is ended, for example, the conversion flag of the first power interval may be set to flag1, where the flag bit of the first conversion branch is a, the flag bit of the second conversion branch is b, and the flag bit of the third conversion branch is c, that is, when the flag bit of the conversion branch when the operation is ended is obtained, the conversion branch when the operation is ended is determined to be the first conversion branch, and when the flag bit of the conversion branch when the operation is ended is obtained to be b, determining that the conversion branch when the last work is finished is a second conversion branch, and when the flag bit of the conversion branch when the last work is finished is obtained to be c, determining that the conversion branch when the last work is finished is a third conversion branch.

Then, the bidirectional DC-DC converter determines the conversion branch which operates first in a cyclic manner of the first conversion branch → the second conversion branch → the third conversion branch → the first conversion branch according to the flag bit of the conversion branch at the last time of ending operation, for example, when the conversion branch at the last time of ending operation is determined to be the first conversion branch, the conversion branch which starts to operate at present is determined to be the second conversion branch, when the conversion branch at the last time of ending operation is determined to be the second conversion branch, the conversion branch which starts to operate at present is determined to be the third conversion branch, and when the conversion branch at the last time of ending operation is determined to be the third conversion branch, the conversion branch which starts to operate at present is determined to be the first conversion branch.

When the bidirectional DC-DC converter works in the first power interval for the first time, the conversion branch which works for the first time is the first conversion branch, and then when the bidirectional DC-DC converter works in the first power interval for each time, the bidirectional DC-DC converter works in a circulating mode of the first conversion branch → the second conversion branch → the third conversion branch → the first conversion branch.

S4: in the process that the first conversion branch, the second conversion branch and the third conversion branch work in turn, if any one conversion branch among the first conversion branch, the second conversion branch and the third conversion branch is identified to have a fault, a controllable switch between a first node and a node of the fault conversion branch is controlled to be closed, so that a standby bridge arm replaces a bridge arm in the fault conversion branch to work in turn.

According to one embodiment of the invention, in the process that the first conversion branch, the second conversion branch and the third conversion branch sequentially work in turn, whether the fault flag bit of the conversion branch to be switched is set is judged when the conversion branch is switched; and if the fault flag bit of the conversion branch to be switched is set, identifying the conversion branch to be switched as a fault conversion branch.

Further, when the conversion branch to be switched is identified as a fault conversion branch, the controllable switch between the first node and the node of the fault conversion branch is controlled to be closed, so that the standby bridge arm replaces the bridge arm of the fault conversion branch to work in turn.

Specifically, in the process that a first conversion branch, a second conversion branch and a third conversion branch sequentially work in turn, whether a fault flag bit of a conversion branch to be converted is set or not is judged when the conversion branches are switched, if the fault flag bit of the conversion branch to be converted is not set, the conversion branch to be converted is controlled to work, if the fault flag bit of the conversion branch to be converted is set, a controllable switch between a first node of a standby bridge arm and a node of the fault conversion branch is controlled to be closed, and the standby bridge arm replaces the fault conversion branch to work.

For example, when the conversion branch to be switched is identified as a fault conversion branch, for example, the first conversion branch is a fault conversion branch, the controllable switch between the first node and the node of the first conversion branch is controlled to be closed, so that when the first conversion branch is turned to work, the upper bridge switching tube and the lower bridge switching tube of the standby bridge arm are controlled to be switched on or off to replace the first conversion branch to work.

According to an embodiment of the invention, when the power to be output is in the second power interval, the upper bridge switching tube and the lower bridge switching tube are controlled, so that two of the first conversion branch, the second conversion branch and the third conversion branch are sequentially in group to work in turn.

It should be noted that the first conversion branch and the second conversion branch may form a first conversion branch group, the first conversion branch and the third conversion branch may form a second conversion branch group, and the second conversion branch and the third conversion branch may form a third conversion branch group. When the power to be output is in the second power interval, the upper bridge switching tube and the lower bridge switching tube of the conversion branch group are controlled, two of the first conversion branch, the second conversion branch and the third conversion branch can be sequentially in a group to work in turn, for example, when the first conversion branch group works, the first upper bridge switching tube and the lower bridge switching tube of the first conversion branch and the second upper bridge switching tube and the second lower bridge switching tube of the second conversion branch can be controlled to be switched on or off, so that the first conversion branch and the second conversion branch are controlled to work, and the upper bridge switching tube and the lower bridge switching tube of the third conversion branch are controlled to be switched off at the moment; when the second conversion branch group works, the first upper bridge switching tube and the first lower bridge switching tube of the first conversion branch and the third upper bridge switching tube and the third lower bridge switching tube of the third conversion branch can be controlled to be switched on or switched off to control the first conversion branch and the third conversion branch to work, and at the moment, the upper bridge switching tube and the lower bridge switching tube of the second conversion branch are switched off; when the third conversion branch group works, the second upper bridge switching tube and the second lower bridge switching tube of the second conversion branch and the third upper bridge switching tube and the third lower bridge switching tube of the third conversion branch can be controlled to be switched on or switched off to control the second conversion branch and the third conversion branch to work, and at the moment, the upper bridge switching tube and the lower bridge switching tube of the first conversion branch are switched off. When the upper bridge switching tube and the lower bridge switching tube are controlled to be switched on or switched off, the upper bridge switching tube can be controlled to be switched on or switched off during forward work, and the lower bridge switching tube can be controlled to be switched on or switched off during reverse work.

Specifically, when the bidirectional DC-DC converter works in a manner that every two of the first conversion branch, the second conversion branch and the third conversion branch sequentially work in turn, the first conversion branch, the second conversion branch → the first conversion branch and the third conversion branch → the second conversion branch and the third conversion branch → the first conversion branch and the second conversion branch are required to work first when the bidirectional DC-DC converter starts to work at present according to the flag bit of the last group of conversion branches when the bidirectional DC-DC converter finishes working.

That is, when the bidirectional DC-DC converter operates, the power interval in which the power to be output is determined after the power to be output is obtained, when the power interval in which the power to be output is located is the second power interval, the flag bits of the group of conversion branches when the bidirectional DC-DC converter finishes operating last time are obtained, and the group of conversion branches which operate last time is determined according to the flag bits of the group of conversion branches when the power to be output finishes operating last time, for example, the conversion flag of the second power interval may be set to flag2, where the flag bits of the first conversion branch and the second conversion branch are a ', the flag bits of the first conversion branch and the third conversion branch are b ', and the flag bits of the second conversion branch and the third conversion branch are c ', that is, when the flag bit of the group of conversion branches when the operation finishes last time is obtained, the group of conversion branches when the operation finishes operating last time is determined to be the first conversion branch and the second conversion branch, when the flag bit of the group of conversion branches when the last work is finished is acquired as b ', the group of conversion branches when the last work is finished is determined as a first conversion branch and a third conversion branch, and when the flag bit of the group of conversion branches when the last work is finished is acquired as c', the group of conversion branches when the last work is finished is determined as a second conversion branch and a third conversion branch.

Then, the bidirectional DC-DC converter determines the conversion branch group which operates first in a cyclic manner of the first conversion branch and the second conversion branch → the first conversion branch and the third conversion branch → the second conversion branch and the third conversion branch → the first conversion branch and the second conversion branch according to the flag bit of the group of conversion branches at the time of last completion of operation, for example, when the group of conversion branches at the time of last completion of operation is determined to be the first conversion branch and the second conversion branch, the conversion branch which currently starts to operate is determined to be the first conversion branch and the third conversion branch, when the group of conversion branches at the time of last completion of operation is determined to be the first conversion branch and the third conversion branch, the conversion branch which currently starts to operate is determined to be the second conversion branch and the third conversion branch, when the group of conversion branches at the time of last completion of operation is determined to be the second conversion branch and the third conversion branch, the conversion branches that are currently starting to operate are determined to be the first conversion branch and the second conversion branch.

When the bidirectional DC-DC converter works in the second power interval for the first time, the conversion branch which works for the first time is a first conversion branch and a second conversion branch, and then the bidirectional DC-DC converter works in a circulating mode of the first conversion branch and the second conversion branch → the first conversion branch and the third conversion branch → the second conversion branch and the third conversion branch → the first conversion branch and the second conversion branch each time. Specifically, each set of conversion branches equally divides the power to be output when in operation.

According to one embodiment of the invention, in the process of sequentially performing alternate work on a group of the first conversion branch, the second conversion branch and the third conversion branch pairwise, whether a fault flag bit of a conversion branch group to be switched is set is judged when the conversion branch group is switched; if the fault flag bit of the conversion branch group to be switched is set, judging that the conversion branch group to be switched is a fault conversion branch group, and continuously judging whether the fault flag bit of the next conversion branch group is set; if the fault flag bit of the next conversion branch group is set, judging that the next conversion branch group is a fault conversion branch group, and identifying repeated conversion branches in the conversion branch group to be switched and the next conversion branch group as fault conversion branches according to the conversion branch group to be switched and the next conversion branch group; and if the fault flag bit of the next conversion branch group is not set, identifying the fault conversion branch in the first conversion branch, the second conversion branch and the third conversion branch according to the fact that the next conversion branch group is not the fault conversion branch group.

That is, if the fault flag bit of the conversion branch group is determined twice continuously, the repeated conversion branch is identified according to the two groups of fault conversion branch groups, and the repeated conversion branch is determined to be a fault branch, so that the controllable switch between the first node of the standby bridge arm and the node of the fault conversion branch is controlled to be closed, and the standby bridge arm replaces the bridge arms in the fault conversion branch to work in turn; if only the fault flag bit of the conversion branch group to be switched is set and the conversion branch group of the next conversion branch group is not set, the fault conversion branch is identified according to the fact that the next conversion branch group is not the fault conversion branch group, and then the controllable switch between the first node of the standby bridge arm and the node of the fault conversion branch is controlled to be closed, so that the standby bridge arm replaces the bridge arm in the fault conversion branch to work in turn.

For example, when the bidirectional DC-DC converter works, the power interval where the power to be output is located is determined after the power to be output is obtained, if the power interval where the power to be output is located is the second power interval, the first converting branch and the second converting branch are controlled to work, when the DC-DC converter stops or jumps out of the second power interval and then works alternately in turn with each other in the first converting branch, the second converting branch and the third converting branch in turn, whether the fault flag bit of the converting branch group to be converted is set, that is, whether the flag bit of the branch group consisting of the first converting branch and the third converting branch is set, if the flag bit of the branch group consisting of the first converting branch and the third converting branch is set, whether the fault flag bit of the next converting branch group is set, that is, whether the flag bit of the branch group consisting of the second converting branch and the third converting branch is set is determined, if the flag bit of the branch group consisting of the second conversion branch and the third conversion branch is set, the third conversion branch overlapped in the two conversion branch groups is judged to be a fault conversion branch, and then the controllable switch between the first node of the standby bridge arm and the node of the third conversion branch is controlled to be closed, so that the standby bridge arm replaces the third conversion branch to work, namely the first conversion branch and the standby bridge arm are controlled to work, if the flag bit of the branch group consisting of the second conversion branch and the third conversion branch is not set, the first conversion branch is judged to be a fault branch, and the controllable switch between the first node of the standby bridge arm and the node of the first conversion branch is controlled to be closed, so that the standby bridge arm replaces the first conversion branch to work, namely the standby bridge arm and the third conversion branch are controlled to work.

According to one embodiment of the invention, when the power to be output is in a third power interval, the upper bridge switching tube and the lower bridge switching tube are controlled so that the first conversion branch, the second conversion branch and the third conversion branch work simultaneously, wherein in the process that the first conversion branch, the second conversion branch and the third conversion branch work simultaneously, if any one conversion branch is identified to be in fault, the controllable switch between the first node and the node of the fault conversion branch is controlled to be closed so that the standby bridge arm replaces the bridge arm in the fault conversion branch.

That is to say, when the power to be output is greater than the preset power, the first conversion branch, the second conversion branch and the third conversion branch of the bidirectional DC-DC conversion branch work simultaneously, wherein the first conversion branch, the second conversion branch and the third conversion branch equally divide the power to be output.

Specifically, when the power to be output is in a third power interval, the upper bridge switching tube and the lower bridge switching tube of the first conversion branch, the second conversion branch and the third conversion branch can be controlled to be switched on or switched off simultaneously, so that the first conversion branch, the second conversion branch and the third conversion branch work simultaneously. For example, the first upper bridge switching tube of the first conversion branch, the second upper bridge switching tube of the second conversion branch and the third upper bridge switching tube of the third conversion branch can be controlled to be switched on or switched off when the DC-DC converter works in the forward direction, and the first lower bridge switching tube of the first conversion branch, the second lower bridge switching tube of the second conversion branch and the lower bridge switching tube of the third conversion branch can be controlled to be switched on or switched off when the DC-DC converter works in the reverse direction. In the process that the first conversion branch, the second conversion branch and the third conversion branch work simultaneously, if any conversion branch is identified to have a fault, the controllable switch between the first node and the node of the fault conversion branch is controlled to be closed, so that the standby bridge arm replaces the bridge arm in the fault conversion branch.

According to an embodiment of the present invention, as shown in fig. 3, the control method of the bidirectional DC-DC converter includes the following steps:

s101: when the bidirectional DC-DC converter is started to work.

S102: and acquiring the power to be output of the bidirectional DC-DC converter.

S103: and judging the power interval where the power to be output is located.

If the power interval in which the power to be output is located is the first power interval, executing step S104;

if the power interval in which the power to be output is located is the second power interval, executing step S109;

if the power interval in which the power to be output is located is the third power interval, step S115 is executed.

S104: and acquiring the zone bit of the conversion branch when the last work is finished.

S105: determining the conversion branch to be switched.

S106: and judging whether the fault flag bit of the conversion branch to be switched is set.

If yes, go to step S107; if not, step S108 is performed.

S107: and controlling a standby bridge arm to work instead of a switching branch with switching.

S108: and controlling the conversion branch with switching to work.

S109: and acquiring the zone bits of the group of conversion branches when the work is finished last time.

S110: the set of conversion branches to be converted is determined.

S111: and judging whether the fault flag bit of the group of conversion branches to be converted is set.

If so, go to step S113; if not, step S112 is performed.

S112: and controlling the group of conversion branches to be converted to work.

S113: and judging whether the fault flag bit of the next conversion branch group is set.

S114: and determining a fault conversion branch and controlling a standby bridge arm to replace the fault conversion branch to work.

S115: and determining that the first transformation branch, the second transformation branch and the third transformation branch work simultaneously.

S116: and if any one conversion branch is identified to have a fault, controlling the standby bridge arm to replace the bridge arm in the fault conversion branch.

In summary, according to the control method of the bidirectional DC-DC converter provided by the embodiment of the present invention, the bidirectional DC-DC converter includes a first converting branch, a second converting branch, a third converting branch and a standby bridge arm, the first converting branch, the second converting branch and the third converting branch are connected in parallel, each of the first converting branch, the second converting branch and the third converting branch includes an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each converting branch are connected in series and have a node as a node of each converting branch, the standby bridge arm includes a standby upper bridge switching tube and a standby lower bridge switching tube, the standby upper bridge switching tube and the standby lower bridge switching tube are connected in series and have a first node, the first node is respectively connected to the node of each converting branch through a controllable switch, the control method obtains the power to be output of the bidirectional DC-DC converter, judging a power interval in which power to be output is positioned, controlling an upper bridge switching tube and a lower bridge switching tube according to the power interval in which the power to be output is positioned so as to control a first conversion branch, a second conversion branch and a third conversion branch to work in turn when the power to be output is smaller than preset power, and controlling a controllable switch between a first node and a node of a fault conversion branch to be closed if any one of the first conversion branch, the second conversion branch and the third conversion branch is identified to have a fault in the process of working in turn of the first conversion branch, the second conversion branch and the third conversion branch so as to enable a standby bridge arm to replace a bridge arm in the fault conversion branch to work in turn. Therefore, the control method provided by the embodiment of the invention can effectively reduce the working time of the switching tube, prolong the working life of the switching tube in the conversion branch, and access the standby bridge arm to work in turn when any conversion branch of the bidirectional DC-DC converter fails, so that the life cycle of the bidirectional DC-DC converter can be prolonged.

Embodiments of the present invention also provide a non-transitory computer-readable storage medium on which a computer program is stored, the program, when executed by a processor, implementing a method of controlling a bidirectional DC-DC converter.

The embodiment of the invention also provides a bidirectional DC-DC converter, which comprises a first conversion branch, a second conversion branch and a third conversion branch, wherein the first conversion branch, the second conversion branch and the third conversion branch are connected in parallel, each of the first conversion branch, the second conversion branch and the third conversion branch comprises an upper bridge switching tube and a lower bridge switching tube, the bidirectional DC-DC converter further comprises a memory, a processor and a control program of the bidirectional DC-DC converter, the control program of the bidirectional DC-DC converter is stored on the memory and can be operated on the processor, and when being executed by the processor, the control program of the bidirectional DC-DC converter realizes the control method of the bidirectional DC-DC converter.

Fig. 4 is a block schematic diagram of a control apparatus of a bidirectional DC-DC converter according to an embodiment of the present invention. The bidirectional DC-DC converter comprises a first conversion branch, a second conversion branch, a third conversion branch and a standby bridge arm, wherein the first conversion branch, the second conversion branch and the third conversion branch are connected in parallel, each conversion branch of the first conversion branch, the second conversion branch and the third conversion branch comprises an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and provided with a node to serve as the node of each conversion branch, the standby bridge arm comprises a standby upper bridge switching tube and a standby lower bridge switching tube, the standby upper bridge switching tube and the standby lower bridge switching tube are connected in series and provided with first nodes, and the first nodes are correspondingly connected to the nodes of each conversion branch through controllable switches respectively.

As shown in fig. 4, the control device of the bidirectional DC-DC converter according to the embodiment of the present invention includes: the device comprises an acquisition module 10, a judgment module 20 and a control module 30.

The obtaining module 10 is configured to obtain power to be output of the bidirectional DC-DC converter; the judging module 20 is configured to judge a power interval in which power to be output is located, where the output power of the bidirectional DC-DC converter is divided into a plurality of power intervals; the control module 30 is configured to control the upper bridge switching tube and the lower bridge switching tube according to a power interval in which power to be output is located, so as to control the first conversion branch, the second conversion branch and the third conversion branch to work in turn when the power to be output is smaller than a preset power, wherein in a process that the first conversion branch, the second conversion branch and the third conversion branch work in turn, if it is identified that any one of the first conversion branch, the second conversion branch and the third conversion branch fails, a controllable switch between a first node and a node of the failed conversion branch is controlled to be closed, so that a standby bridge arm replaces a bridge arm in the failed conversion branch to work in turn.

According to an embodiment of the present invention, the plurality of power intervals are a first power interval, a second power interval and a third power interval, the power corresponding to the second power interval is greater than the power corresponding to the first power interval, the power corresponding to the third power interval is greater than the power corresponding to the second power interval, and the upper limit value of the second power interval is a preset power, where the preset power may be 200kw, specifically, the first power interval may be 0kw-100kw, the second power interval may be 100kw-200kw, and the third power interval may be 200kw-300 kw.

The control module 30 is further configured to control the upper bridge switching tube and the lower bridge switching tube when the power to be output is in the first power interval, so that the first conversion branch, the second conversion branch and the third conversion branch work in turn.

Specifically, the first conversion branch, the second conversion branch and the third conversion branch respectively have different flag bits when operating, wherein when the bidirectional DC-DC converter operates in a manner that the first conversion branch, the second conversion branch and the third conversion branch sequentially operate in turn each time, the control module 30 is further configured to determine, when the bidirectional DC-DC converter currently starts operating, the conversion branch which operates first in a cyclic manner of the first conversion branch → the second conversion branch → the third conversion branch → the first conversion branch according to the flag bit of the conversion branch when the operation of the bidirectional DC-DC converter is finished last time.

That is, when the bidirectional DC-DC converter operates, after the obtaining module 10 obtains the power to be output, the determining module 20 determines the power interval in which the power to be output is located, and when the power interval in which the power to be output is located is the first power interval, obtains the flag bit of the last conversion branch of the bidirectional DC-DC converter when the operation is ended, and determines the last conversion branch according to the flag bit of the last conversion branch when the operation is ended, for example, the conversion flag of the first power interval may be set to flag1, where the flag bit of the first conversion branch is a, the flag bit of the second conversion branch is b, and the flag bit of the third conversion branch is c, that is, when the flag bit of the last conversion branch when the operation is ended is a, the conversion branch when the operation is ended is determined to be the first conversion branch, and when the flag bit of the last conversion branch when the operation is ended is b, determining that the conversion branch when the last work is finished is a second conversion branch, and when the flag bit of the conversion branch when the last work is finished is obtained to be c, determining that the conversion branch when the last work is finished is a third conversion branch.

Then, the bidirectional DC-DC converter determines the conversion branch which operates first in a cyclic manner of the first conversion branch → the second conversion branch → the third conversion branch → the first conversion branch according to the flag bit of the conversion branch at the time of last ending of operation, for example, when the conversion branch at the time of last ending of operation is determined to be the first conversion branch, the control module 30 determines the conversion branch which starts to operate currently to be the second conversion branch, when the conversion branch at the time of last ending of operation is determined to be the second conversion branch, the control module 30 determines the conversion branch which starts to operate currently to be the third conversion branch, and when the conversion branch at the time of last ending of operation is determined to be the third conversion branch, the control module 30 determines the conversion branch which starts to operate currently to be the first conversion branch.

According to an embodiment of the present invention, the control module 30 is further configured to, in a process that the first transforming branch, the second transforming branch and the third transforming branch sequentially perform alternate work, determine whether a fault flag bit of the transforming branch to be switched is set when the transforming branch is switched; and if the fault flag bit of the conversion branch to be switched is set, identifying the conversion branch to be switched as a fault conversion branch.

Further, when the conversion branch to be switched is identified as a fault conversion branch, the controllable switch between the first node J1 and the node of the fault conversion branch is controlled to be closed, so that the standby bridge arms replace the bridge arms of the fault conversion branch to work in turn.

Specifically, in the process that a first conversion branch, a second conversion branch and a third conversion branch sequentially work in turn, whether a fault flag bit of a conversion branch to be converted is set or not is judged when the conversion branches are switched, if the fault flag bit of the conversion branch to be converted is not set, the conversion branch to be converted is controlled to work, if the fault flag bit of the conversion branch to be converted is set, a controllable switch between a first node J1 of a standby bridge arm and a node of the fault conversion branch is controlled to be closed, and the standby bridge arm replaces the fault conversion branch to work.

According to an embodiment of the present invention, the control module 30 is further configured to control the upper bridge switching tube and the lower bridge switching tube when the power to be output is in the second power interval, so that two of the first conversion branch, the second conversion branch and the third conversion branch are a group and work in turn.

Specifically, the flag bits of the first, second, and third transformation branches when working in turn are different, wherein when the bidirectional DC-DC converter works in turn in each time in a manner that two of the first, second, and third transformation branches are in turn working, the control module 30 is further configured to determine the transformation branch group that works first in a cyclic manner of the first, second, and third transformation branches → the first and second transformation branches according to the flag bits of the last transformation branch when working is finished when the bidirectional DC-DC converter starts working.

That is, when the bidirectional DC-DC converter operates, after the obtaining module 10 obtains the power to be output, the determining module 20 determines the power interval in which the power to be output is located, and when the power interval in which the power to be output is located is the second power interval, obtains the flag bits of the group of converting branches when the bidirectional DC-DC converter last finishes operating, and determines the group of converting branches last operating according to the flag bits of the group of converting branches last finishing operating, for example, the converting flag of the second power interval may be set to flag2, where the flag bits of the first converting branch and the second converting branch are a ', the flag bits of the first converting branch and the third converting branch are b', and the flag bits of the second converting branch and the third converting branch are c ', that is, when the flag bit of the group of converting branches last finishing operating is a', the control module 30 determines that the group of conversion branches at the last time of finishing the operation are the first conversion branch and the second conversion branch, when the flag bit of the group of conversion branches at the last time of finishing the operation is obtained as b ', the control module 30 determines that the group of conversion branches at the last time of finishing the operation are the first conversion branch and the third conversion branch, and when the flag bit of the group of conversion branches at the last time of finishing the operation is obtained as c', the control module 30 determines that the group of conversion branches at the last time of finishing the operation are the second conversion branch and the third conversion branch.

Then, the bidirectional DC-DC converter determines the conversion branch group which operates first in a cyclic manner of the first conversion branch and the second conversion branch → the first conversion branch and the third conversion branch → the second conversion branch and the third conversion branch → the first conversion branch and the second conversion branch according to the flag bit of the group of conversion branches at the last time of ending operation, for example, when the group of conversion branches at the last time of ending operation is determined to be the first conversion branch and the second conversion branch, the control module 30 determines the conversion branch which starts to operate at present to be the first conversion branch and the third conversion branch, when the group of conversion branches at the last time of ending operation is determined to be the first conversion branch and the third conversion branch, the control module 30 determines the conversion branch which starts to operate at present to be the second conversion branch and the third conversion branch, when the group of conversion branches at the last time of ending operation is determined to be the second conversion branch and the third conversion branch, the control module 30 determines the currently active shift leg as the first shift leg and the second shift leg.

According to an embodiment of the present invention, the control module 30 is further configured to, in a process that two of the first transformation branch, the second transformation branch and the third transformation branch are grouped into one group and sequentially perform alternate work, determine whether a fault flag bit of the transformation branch group to be switched is set when the transformation branch group is switched; if the fault flag bit of the conversion branch group to be switched is set, judging that the conversion branch group to be switched is a fault conversion branch group, and continuously judging whether the fault flag bit of the next conversion branch group is set; if the fault flag bit of the next conversion branch group is set, judging that the next conversion branch group is a fault conversion branch group, and identifying repeated conversion branches in the conversion branch group to be switched and the next conversion branch group as fault conversion branches according to the conversion branch group to be switched and the next conversion branch group; and if the fault flag bit of the next conversion branch group is not set, identifying the fault conversion branch in the first conversion branch, the second conversion branch and the third conversion branch according to the fact that the next conversion branch group is not the fault conversion branch group.

According to an embodiment of the present invention, the control module 30 is further configured to, when the power to be output is in a third power interval, control the upper bridge switching tube and the lower bridge switching tube to enable the first conversion branch, the second conversion branch, and the third conversion branch to operate simultaneously, where in a process that the first conversion branch, the second conversion branch, and the third conversion branch operate simultaneously, if it is identified that any one conversion branch fails, the controllable switch between the first node and the node of the failed conversion branch is controlled to be closed, so that the standby bridge arm replaces the bridge arm in the failed conversion branch.

Wherein, the three transformation branches equally divide the power to be output.

The embodiment of the invention also provides a bidirectional DC-DC converter.

Fig. 5 is a block schematic diagram of a bidirectional DC-DC converter according to an embodiment of the invention. As shown in fig. 5, the bidirectional DC-DC converter 200 according to the embodiment of the present invention includes the control device 100 of the bidirectional DC-DC converter.

The embodiment of the invention also provides a train.

Fig. 6 is a block schematic diagram of a train according to an embodiment of the invention. As shown in fig. 6, the train 300 of the embodiment of the present invention includes a bidirectional DC-DC converter 200.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are 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 the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A control method of a bidirectional DC-DC converter is characterized in that the bidirectional DC-DC converter comprises a first conversion branch, a second conversion branch, a third conversion branch and a standby bridge arm, the first conversion branch, the second conversion branch and the third conversion branch are connected in parallel, each conversion branch of the first conversion branch, the second conversion branch and the third conversion branch comprises an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and provided with a node to serve as a node of each conversion branch, the standby bridge arm comprises a standby upper bridge switching tube and a standby lower bridge switching tube, the standby upper bridge switching tube and the standby lower bridge switching tube are connected in series and provided with a first node, and the first node is correspondingly connected to the node of each conversion branch through a controllable switch respectively, the control method comprises the following steps:

acquiring the power to be output of the bidirectional DC-DC converter;

judging a power interval in which the power to be output is positioned, wherein the output power of the bidirectional DC-DC converter is divided into a plurality of power intervals;

controlling the upper bridge switching tube and the lower bridge switching tube according to the power interval of the power to be output so as to control the first conversion branch, the second conversion branch and the third conversion branch to work in turn when the power to be output is smaller than the preset power;

in the process of alternately working the first conversion branch, the second conversion branch and the third conversion branch, if any one conversion branch in the first conversion branch, the second conversion branch and the third conversion branch is identified to have a fault, controlling a controllable switch between a first node and a node of the fault conversion branch to be closed so as to enable the standby bridge arm to replace a bridge arm in the fault conversion branch to alternately work;

the multiple power intervals are a first power interval, a second power interval and a third power interval, the power corresponding to the second power interval is greater than the power corresponding to the first power interval, the power corresponding to the third power interval is greater than the power corresponding to the second power interval, and the upper limit value of the second power interval is the preset power, wherein when the power to be output is in the second power interval, the upper bridge switching tube and the lower bridge switching tube are controlled, so that two of the first conversion branch, the second conversion branch and the third conversion branch work in turn;

the flag bits of the first conversion branch, the second conversion branch and the third conversion branch which are two by two in the first conversion branch, the second conversion branch and the third conversion branch which are sequentially operated in turn are different, wherein when the bidirectional DC-DC converter is operated in a mode that the first conversion branch, the second conversion branch and the third conversion branch which are two by two in the first conversion branch, the second conversion branch and the third conversion branch which are sequentially operated in turn each time, the bidirectional DC-DC converter needs to determine the conversion branch group which is operated firstly according to the cycle mode of the first conversion branch, the second conversion branch, the first conversion branch, the third conversion branch → the second conversion branch and the third conversion branch → the first conversion branch and the second conversion branch when the bidirectional DC-DC converter is started to operate at present.

2. The control method of a bidirectional DC-DC converter according to claim 1,

and when the power to be output is in the first power interval, controlling the upper bridge switching tube and the lower bridge switching tube so as to enable the first conversion branch, the second conversion branch and the third conversion branch to work in turn.

3. The method according to claim 2, wherein during the sequential alternate operation of the first, second and third conversion branches, it is determined whether the fault flag bit of the conversion branch to be switched is set when switching the conversion branch;

and if the fault flag bit of the conversion branch to be switched is set, identifying the conversion branch to be switched as a fault conversion branch.

4. The method according to claim 2, wherein in the process of sequentially performing alternate operation on two of the first, second and third conversion branches as a group, whether the fault flag bit of the conversion branch group to be switched is set is determined when the conversion branch group is switched;

if the fault flag bit of the conversion branch group to be switched is set, judging that the conversion branch group to be switched is a fault conversion branch group, and continuously judging whether the fault flag bit of the next conversion branch group is set;

if the fault flag bit of the next conversion branch group is set, judging that the next conversion branch group is a fault conversion branch group, and identifying repeated conversion branches in the conversion branch group to be switched and the next conversion branch group as fault conversion branches according to the conversion branch group to be switched and the next conversion branch group as the fault conversion branch group;

and if the fault flag bit of the next conversion branch group is not set, identifying the fault conversion branch in the first conversion branch, the second conversion branch and the third conversion branch according to the fact that the next conversion branch group is not the fault conversion branch group.

5. The method of claim 2, wherein when the power to be outputted is in the third power interval, the up-bridge switch tube and the down-bridge switch tube are controlled to operate the first conversion branch, the second conversion branch and the third conversion branch simultaneously, wherein,

in the process that the first conversion branch, the second conversion branch and the third conversion branch work simultaneously, if any conversion branch is identified to have a fault, the controllable switch between the first node and the node of the fault conversion branch is controlled to be closed, so that the standby bridge arm replaces the bridge arm in the fault conversion branch.

6. The method according to claim 2, wherein the first, second, and third conversion branches have different flag bits when operating, and wherein when the bidirectional DC-DC converter operates in a manner that the first, second, and third conversion branches sequentially operate in turn each time, the first conversion branch → the second conversion branch → the third conversion branch → the first conversion branch needs to be determined in a cyclic manner according to the flag bit of the conversion branch when the operation is finished last time when the bidirectional DC-DC converter starts to operate at present.

7. A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that the program, when executed by a processor, implements the control method of the bidirectional DC-DC converter according to any one of claims 1 to 6.

8. A bidirectional DC-DC converter is characterized by comprising a first conversion branch, a second conversion branch, a third conversion branch and a standby bridge arm, wherein the first conversion branch, the second conversion branch and the third conversion branch are connected in parallel, each of the first conversion branch, the second conversion branch and the third conversion branch comprises an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and provided with a node to serve as the node of each conversion branch, the standby bridge arm comprises a standby upper bridge switching tube and a standby lower bridge switching tube, the standby upper bridge switching tube and the standby lower bridge switching tube are connected in series and provided with first nodes, the first nodes are correspondingly connected to the nodes of each conversion branch through controllable switches, and the bidirectional DC-DC converter further comprises a memory, a first storage, a second conversion branch and a standby bridge arm, A processor and a control program for a bidirectional DC-DC converter stored on the memory and running on the processor, the control program for the bidirectional DC-DC converter, when executed by the processor, implementing a control method for the bidirectional DC-DC converter according to any one of claims 1 to 7.

9. A control device of a bidirectional DC-DC converter is characterized in that the bidirectional DC-DC converter comprises a first conversion branch, a second conversion branch, a third conversion branch and a standby bridge arm, the first conversion branch, the second conversion branch and the third conversion branch are connected in parallel, each conversion branch of the first conversion branch, the second conversion branch and the third conversion branch comprises an upper bridge switching tube and a lower bridge switching tube, the upper bridge switching tube and the lower bridge switching tube in each conversion branch are connected in series and provided with a node to serve as a node of each conversion branch, the standby bridge arm comprises a standby upper bridge switching tube and a standby lower bridge switching tube, the standby upper bridge switching tube and the standby lower bridge switching tube are connected in series and provided with a first node, and the first nodes are correspondingly connected to the nodes of each conversion branch through controllable switches respectively, the control device includes:

the acquisition module is used for acquiring the power to be output of the bidirectional DC-DC converter;

the judging module is used for judging a power interval where the power to be output is located, wherein the output power of the bidirectional DC-DC converter is divided into a plurality of power intervals;

a control module, configured to control the upper bridge switching tube and the lower bridge switching tube according to a power interval in which the power to be output is located, so as to control the first conversion branch, the second conversion branch, and the third conversion branch to work in turn when the power to be output is smaller than a preset power,

the plurality of power intervals are a first power interval, a second power interval and a third power interval, the power corresponding to the second power interval is greater than the power corresponding to the first power interval, the power corresponding to the third power interval is greater than the power corresponding to the second power interval, and the upper limit value of the second power interval is the preset power, wherein the control module is further configured to: when the power to be output is in the second power interval, controlling the upper bridge switching tube and the lower bridge switching tube so as to enable every two of the first conversion branch, the second conversion branch and the third conversion branch to be a group and to work in turn;

the control module is further configured to determine a conversion branch group which works first in a circulating manner of the first conversion branch, the second conversion branch, the third conversion branch → the second conversion branch and the third conversion branch → the first conversion branch and the third conversion branch → the second conversion branch and the third conversion branch → the first conversion branch and the second conversion branch.

10. The control device of a bidirectional DC-DC converter according to claim 9,

11. The control device of claim 10, wherein the control module is further configured to determine whether a fault flag bit of a switching branch to be switched is set when switching the switching branch during the sequential alternate operation of the first switching branch, the second switching branch and the third switching branch;

12. The control device of claim 9, wherein the control module is further configured to determine whether a fault flag bit of a to-be-switched switching branch group is set when switching the switching branch group during a process of performing a rotation operation on two of the first, second, and third switching branches in turn;

13. The apparatus of claim 10, wherein the control module is further configured to control the upper switching tube and the lower switching tube to operate the first converting branch, the second converting branch and the third converting branch simultaneously when the power to be outputted is in the third power interval, wherein,

14. The apparatus of claim 10, wherein the first, second and third transforming branches have different flags when operating, and wherein the control module is further configured to determine the first converting branch to operate first according to the flag of the last converting branch when the bidirectional DC-DC converter starts to operate at present, when the bidirectional DC-DC converter operates in a manner that the first, second and third transforming branches operate in turn each time, in a cyclic manner of first converting branch → second converting branch → third converting branch → first converting branch.

15. A bidirectional DC-DC converter, characterized by comprising a control device of the bidirectional DC-DC converter according to any one of claims 9 to 14.

16. Train, characterized in that it comprises a bidirectional DC-DC converter according to claim 8 or 15.