CN112448382B

CN112448382B - DC-DC converter and control method thereof

Info

Publication number: CN112448382B
Application number: CN201910818659.0A
Authority: CN
Inventors: 沈林; 梁树林
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2023-04-07
Anticipated expiration: 2039-08-30
Also published as: CN112448382A

Abstract

The present disclosure relates to a DC-DC converter and a control method thereof, the DC-DC converter including: the system comprises an input end, an output end, a plurality of parallel conversion modules and a main control board; the main control board is connected with each conversion module; the main control board is used for: according to the required output power, determining a target number of required conversion modules and a plurality of required module power ranges, selecting the conversion module with the lowest accumulated working time length in each required module power range according to the target number in the plurality of parallel conversion modules, and setting the power range of the selected conversion module as the corresponding required module power range. Therefore, the working time of each conversion module in each module power range can be ensured to be consistent, and the load of each conversion module is more balanced.

Description

DC-DC converter and control method thereof

Technical Field

The present disclosure relates to the field of power electronics, and in particular, to a DC-DC converter and a control method thereof.

Background

DC-DC converters are a type of power conversion devices that convert a DC voltage source into a DC voltage source required by a load. DC-DC converters are a fundamental component in the construction of many other types of power converters, which are widely used in electric locomotives, subways, city trolleys, battery cars, and switching power supplies.

At present, for a multi-module parallel DC-DC converter, because the modules are different in hardware model and the hardware parameters of the modules are greatly different, the loads of the modules of the DC-DC converter are unbalanced. For example, some modules operate in a fully loaded state for a long period of time, and some modules are lightly loaded or in an unloaded state for a long period of time.

Disclosure of Invention

The present disclosure is directed to a DC-DC converter and a control method thereof, so as to solve the problem of unbalanced load of each module in the DC-DC converter in the related art.

According to a first aspect of the embodiments of the present disclosure, there is provided a DC-DC converter, including an input terminal, an output terminal, a plurality of parallel conversion modules, and a main control board;

the main control board is connected with each conversion module;

the main control board is used for: according to the required output power, determining a target number of required conversion modules and a plurality of required module power ranges, selecting the conversion module with the lowest accumulated working time length in each required module power range according to the target number in the plurality of parallel conversion modules, and setting the power range of the selected conversion module as the corresponding required module power range.

Optionally, the main control board prestores a corresponding relationship between a required output power range and the number of conversion modules and the module power range, and is configured to:

determining a required output power range in which the required output power is located;

and determining the target number of the conversion modules corresponding to the required output power range and the module power range of each requirement according to the corresponding relation.

Optionally, the main control board is configured to: detecting whether a conversion module with a fault exists in the selected conversion modules;

if the conversion module with the fault exists, determining whether the sum of the maximum actual output power of the conversion modules without the fault is smaller than the required output power;

and if the sum of the maximum actual output power of the conversion modules without faults is less than the required output power, sending alarm information.

Optionally, the DC-DC converter is a bidirectional DC-DC converter, the input terminal includes a forward input terminal and a backward input terminal, and the output terminal includes a forward output terminal and a backward output terminal.

According to a second aspect of the embodiments of the present disclosure, there is provided a method for controlling a DC-DC converter, the DC-DC converter including an input terminal, an output terminal, a plurality of parallel conversion modules, and a main control board, the method including:

the main control board determines a target number of required conversion modules and a plurality of required module power ranges according to the required output power, selects the conversion module with the lowest accumulated working time length in each required module power range according to the target number in the plurality of parallel conversion modules, and sets the power range of the selected conversion module as the corresponding required module power range.

Optionally, the main control board prestores a corresponding relationship between a required output power range and the number of conversion modules and the module power range; determining a target number of required conversion modules and a plurality of required module power ranges according to the required output power, comprising:

Optionally, the method further comprises:

detecting whether a conversion module with a fault exists in the selected conversion modules;

Through the technical scheme, the following technical effects can be at least achieved:

the required output power is determined through the main control board, the target number of required conversion modules and a plurality of required module power ranges are determined according to the required output power, the conversion module with the lowest accumulated working time length in each required module power range is selected according to the target number in the plurality of parallel conversion modules, and the power range of the selected conversion module is set as the corresponding required module power range. By adopting the method, the conversion module with the lowest accumulated working time length in the range is selected in the power range of each demand module, and the required output power is distributed to the selected conversion module for output, so that the working time lengths of the conversion modules in the power range of each module can be ensured to be consistent, and the loads of the conversion modules are more balanced.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

fig. 1 is a schematic diagram illustrating a DC-DC converter according to an exemplary embodiment.

Fig. 2 is a schematic diagram of a bi-directional DC-DC converter shown in accordance with an exemplary embodiment.

Fig. 3 is a flow chart illustrating a method of controlling a DC-DC converter according to an exemplary embodiment.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The disclosed embodiment provides a DC-DC converter, as shown in fig. 1, the DC-DC converter 100 includes an input terminal 101, an output terminal 102, a plurality of parallel conversion modules 103 (such as the conversion modules 1 to N shown in fig. 1), and a main control board 104;

the main control board 104 is connected with each conversion module 103;

the main control board 104 is configured to: according to the required output power, determining a target number of required conversion modules 103 and a plurality of required module power ranges, selecting the conversion module 103 with the lowest accumulated working time length in each required module power range according to the target number from the plurality of parallel conversion modules 103, and setting the selected power range of the conversion module 103 as the corresponding required module power range.

The main control board 104 and each conversion module 103 may communicate by using a Controller Area Network (CAN), or may communicate by using RS485, ethernet, or the like. The disclosure is not limited thereto.

It is noted that a plurality of module power ranges may be set in the conversion modules in advance, and for example, if the DC-DC converter includes 20 conversion modules and the maximum output power of the DC-DC converter is 500W, the module power ranges of each conversion module in the converter may be set to 0 to 5W,5 to 10W,10 to 10 5W,15 to 20w, and 20 to 25W. In a possible case, since the model numbers, hardware parameters, and the like of the respective conversion modules may be different, and the maximum output powers of the respective conversion modules may be different, the module power ranges of each conversion module may be set individually, for example, if the maximum output power of a conversion module is 20W, the plurality of module power ranges of the conversion module may be set to 0 to 5W,5 to 10w,10 to 15w,15 to 20W. For example, when the maximum output power of the conversion module is 22W, the plurality of module power ranges of the conversion module may be set to 0 to 5w,5 to 10w,10 to 15w,15 to 20w, and 20w to 22W. For example, when the maximum output power of the conversion module is 30W, the plurality of module power ranges of the conversion module may be set to 0 to 5w,5 to 10w,10 to 15w,15 to 20w,20w to 25w, and 25w to 30W.

For each module power range of each conversion module 103, the accumulated operating time (i.e., the historical operating time) of each conversion module in each module power range may be recorded, so that the accumulated operating time of each conversion module 103 in each module power range may be known, and one or more conversion modules with the lowest accumulated operating time in each module power range may be known. The accumulated operating time of each conversion module 103 in each module power range may be recorded by each conversion module 103, or the operating state of each conversion module 103 may be monitored by the main control board 104.

Illustratively, if the module power range of each conversion module in the DC-DC converter is 0-5W, 5-10W, 10-15W, 15-20W, and 20-25W. The cumulative operating time of each conversion module in each module power range may be recorded for the module power ranges 0-5w, 5-10w, 10-15w, 15-20w, and 20-25W, respectively. For example, if the module power range is 0-5W, the cumulative operating time of the conversion module 1 is 10 hours; the accumulated working time of the conversion module 2 is 8 hours; if the accumulated operating time of the conversion module 3 is 6 hours, the conversion modules 1 to 3 may be sorted from small to large according to the accumulated operating time of the conversion modules, and the sorting result of the conversion modules is obtained as follows: conversion module 3, conversion module 2, conversion module 1. Thus, it is known that the conversion module 3 is the conversion module with the lowest accumulated operating time in the module power range of 0-5W.

For another example, if there are different conversion modules having the maximum output power among the conversion modules of the DC-DC converter, the module power ranges of the conversion modules are different. For example, if the module power range of the conversion module 1 is 0 to 5w,5 to 10w,10 to 15w,15 to 20W; the module power range of the conversion module 2 is 0-5W, 5-10W, 10-15W, 15-20W and 20W-22W; the module power ranges of the conversion module 3 are 0-5W, 5-10W, 10-15W, 15-20W and 20-25W. Then for a module power range of 20-25W the cumulative operating time of the conversion module 2 and the conversion module 3 need to be recorded, and the cumulative operating time of the conversion module 1 in this range need not be recorded. If the accumulated working time of the conversion module 2 is 5 hours and the accumulated working time of the conversion module 3 is 10 hours within the module power range of 20-25W, the conversion modules 2 and 3 can be sorted from large to small according to the accumulated working time of the conversion modules, and the sorting result of the conversion modules is obtained as follows: a conversion module 3 and a conversion module 2. Thus, it is known that the converter module 2 is the converter module with the lowest cumulative operating time in the module power range of 20 to 25W.

The module power ranges for the plurality of demands may be determined based on the demanded output power and the target number of corresponding demand conversion modules. And in the required module power range, respectively selecting one or more conversion modules with the lowest historical working time, and taking the module power range corresponding to the selected conversion module as the required module power range.

With the above-described DC-DC converter 100, one or more conversion modules having the lowest accumulated operating time period in each module power range are obtained by dividing the maximum output power of each conversion module 103 into a plurality of module power ranges and then determining the accumulated operating time period of each conversion module 103 in each module power range. And determining the target number of conversion modules needing to do work according to the current required output power, and determining the required module power range. The conversion module with the lowest accumulated working time length in the required module power range is selected to work according to the target number, so that the working time lengths of the conversion modules 103 in the module power ranges can be ensured to be consistent, and the loads of the conversion modules 103 can be more balanced.

Optionally, in the main control board 104 of the DC-DC converter 100, a correspondence relationship between the required output power range and the number of the conversion modules 103 and the module power range is pre-stored, and the main control board 104 may be configured to: determining a required output power range in which the required output power is located;

and determining the target number of the conversion modules 103 corresponding to the required output power range and the module power range of each requirement according to the corresponding relation.

The required output power range may be preset, and specifically, may be set according to a maximum output power corresponding to a model of the DC-DC converter. For example, if the maximum output power of the DC-DC converter is 500W, the power value of 500W may be divided according to the demand to obtain 5 ranges of demanded output power, which are 0 to 100w,100 to 200w,200 to 300w,300 to 400w, and 400 to 500W, respectively. Similarly, the power 500W may be divided into a plurality of other required output power ranges, for example, the required output power ranges may be 0-50W, 50-100W, 100-200W, 200-300W, 300-400W, and 400-500W.

In an implementation manner, a corresponding relationship between the required output power range and the number of the conversion modules 103 and the module power range may be pre-stored in the main control board 104, where the number of the conversion modules 103 in the corresponding relationship is the target number of the conversion modules corresponding to the required output power. Specifically, the required output power range may be determined according to the required output power, and then the number of the conversion modules corresponding to the required output power range and the required module power range may be determined. For example, if 20 conversion modules are connected in parallel in the DC-DC converter, the maximum output power of each conversion module is 20W, and the module power range corresponding to each conversion module is: 0 to 5W,5 to 10W,10 to 15W, and 15 to 20W. If the required output power is 80W, the required output power is within the required output power range of 50-100W. At this time, it may be determined that a maximum of 5 conversion modules are required to perform work within the required output power range according to the upper limit value 100W in the required output power range and the maximum output power 20W of each conversion module. Thus, the required output power range is set to be 50-100W, and the number of the corresponding conversion modules is 5. Therefore, the target number of conversion modules for the required output power 80W is 5.

Further, after determining the target number of conversion modules, the required module power range may be determined according to the required output power of 80W and the target number of 5. Illustratively, the conversion module with the lowest accumulated working time length in each module power range of 0-5W, 5-10W, 10-15W and 15-20W is searched. Assuming that the conversion module 1 and the conversion module 2 are the modules with the lowest accumulated working time length respectively queried in the module power range of 5-10W and the module power range of 10-15W, and the conversion module 3, the conversion module 4 and the conversion module 5 are the three conversion modules with the lowest accumulated working time length found in the module power range of 15-20W, then output power of 8W may be allocated to the conversion module 1, output power of 15W may be allocated to the conversion module 2, power of 18W may be allocated to the conversion module 3, power of 19W may be allocated to the conversion module 4, and power of 20W may be allocated to the conversion module 5. Thus, the total output power of the conversion modules 1-5 is 80W. In another possible allocation manner, the output power 5W may be allocated to the conversion module 1, the output power 15W may be allocated to the conversion module 2, the output power 20W may be allocated to the conversion module 3, the output power 20W may be allocated to the conversion module 4, and the output power 20W may be allocated to the conversion module 5.

It can be known that, if the module power ranges corresponding to the output powers respectively allocated to the selected conversion modules 1 to 5 are 5 to 10w,10 to 15w,15 to 20w, and 15 to 20W, the module power ranges of 5 to 10w,10 to 15w, and 15 to 20W are the above-mentioned required module power ranges.

By adopting the DC-DC converter 100, the corresponding relationship between the required output power range and the number of conversion modules and the module power range can be pre-stored in the main control board 104, so as to implement a method for determining the target number of the required conversion modules 103 and the plurality of required module power ranges according to the required output power, thereby distributing corresponding output power to each selected conversion module 103, and further enabling each conversion module 103 to carry loads within each module power range. This way, the load of each conversion module 103 in the DC-DC converter 100 can be more balanced.

Optionally, the main control board 104 in the DC-DC converter 100 may be configured to: detecting whether a conversion module with a fault exists in the selected conversion modules; if the conversion module with the fault exists, determining whether the sum of the maximum actual output power of the conversion modules without the fault is smaller than the required output power; and if the sum of the maximum actual output power of the conversion modules without faults is less than the required output power, sending alarm information.

In a possible case, there may be a faulty conversion module in the selected conversion module, and the faulty conversion module cannot output the allocated output power, so that the total output power output by the selected conversion module may not meet the required output power. For example, in the above example, the converter modules 1 to 5 output powers of 8W, 15W, 18W, 19W and 20W, respectively, and if the converter module 1 fails to output power due to a fault, the converter modules 2 to 5 in the selected converter modules 1 to 5 are respectively allocated with the power of 20W, so that the required output power of 80W can still be output.

For another example, if both of the converter modules 1 and 2 in the selected converter modules 1 to 5 fail, in this case, the maximum output power that can be output by the selected converter modules 1 to 5 is 60W, and the required output power is not 80W. In this case, in an implementation manner, according to a preset corresponding relationship between the required output power range and the number of conversion modules and the module power range, the faulty conversion module in the conversion module selected in the previous step may be removed, for example, the conversion module 1 and the conversion module 2 are removed, and then the conversion module without fault with the lowest accumulated operating time in each module power range is reselected to do work. It is worth noting that the range of module power that may be required may change after the conversion module is reselected. Therefore, when the correspondence relationship between the required output power range and the number of conversion modules and the module power range is set, the correspondence relationship between the required output power range and the number of conversion modules and the module power range is not limited to one-to-one, and may be a many-to-many relationship. Specifically, a plurality of possible correspondence relationships may be set by past data or experience, and an optimal correspondence relationship table may be set in one possible case.

In another possible case, if the sum of the maximum actual output powers of all the non-faulty conversion modules in the DC-DC converter is still smaller than the current required output power, the DC-DC converter sends an alarm message to prompt the user to control the DC-DC converter to stop the current operation. The alarm information can be character prompt information or alarm sound prompt.

By adopting the above DC-DC converter 100, when the selected conversion module 103 cannot output the required output power, it may be further determined whether the sum of the maximum actual output powers of all the conversion modules 103 that do not fail is smaller than the current required output power, and if the sum of the maximum actual output powers of the conversion modules 103 that do not fail is smaller than the current required output power, an alarm message may be sent to enable a user to timely turn off the DC-DC converter 100 or control the DC-DC converter 100 to automatically stop working, thereby preventing the DC-DC converter 100 from being lost. If the sum of the maximum actual output powers of the conversion modules 103 that do not have a fault is not less than the current required output power, the conversion module 103 that does not have a fault and has the lowest accumulated operating time within the power range of each module may be further reselected to do work.

Alternatively, the DC-DC converter may be a bidirectional DC-DC converter, such as the bidirectional DC-DC converter 200 in fig. 2, wherein the input terminals include a forward input 2011 and a reverse input 2012, and the output terminals include a forward output terminal 2021 and a reverse output terminal 2022.

That is to say, the load balance of each conversion module in the power range of each module can be controlled by adding the main control board regardless of the unidirectional DC-DC converter or the bidirectional DC-DC converter, so as to realize the load balance of each conversion module.

Specifically, the target number of the required conversion modules 103 and the plurality of required module power ranges may be determined according to the forward required output power, and the conversion module 103 with the lowest accumulated operating time in each required module power range is selected from the plurality of parallel conversion modules 103 according to the target number, so as to allocate the forward output power to the selected conversion module 103.

The target number of the required conversion modules 103 and the plurality of required module power ranges can also be determined according to the reverse required output power, the conversion module 103 with the lowest accumulated working time length in each required module power range is selected in the plurality of parallel conversion modules 103 according to the target number, and the main control board distributes the reverse output power to the selected conversion module 103.

An embodiment of the present disclosure further provides a method for controlling a DC-DC converter, as shown in fig. 3, where the DC-DC converter includes an input end, an output end, a plurality of parallel conversion modules, and a main control board, and the method may include the following steps:

s101, determining the target number of required conversion modules and a plurality of required module power ranges according to required output power;

s102, selecting the conversion module with the lowest accumulated working time length in each required module power range according to the target number in the plurality of parallel conversion modules, and setting the power range of the selected conversion module as the corresponding required module power range.

In this way, the one or more conversion modules with the lowest accumulated operating time within each module power range are obtained by dividing the maximum output power of each conversion module into a plurality of module power ranges and then determining the accumulated operating time of each conversion module within each module power range. And determining the target number of the conversion modules needing to do work according to the current required output power, and determining the required module power range. One or more conversion modules with the lowest accumulated working time length in the required module power range are selected to work according to the target number, so that the working time lengths of the conversion modules in the module power ranges can be ensured to be consistent, and the loads of the conversion modules can be balanced.

Optionally, the main control board pre-stores a corresponding relationship between a required output power range and the number of conversion modules and the module power range; determining a target number of required conversion modules and a plurality of required module power ranges according to the required output power may include the steps of:

By adopting the method, the corresponding relation between the required output power range and the number of the conversion modules and the module power range can be prestored in the main control panel, the required number of the conversion modules and the required module power range can be determined according to the required output power through the corresponding relation, and then the selected conversion modules are controlled to output corresponding power. According to the method, different conversion modules are selected when the required output power is different, and the selected conversion modules are controlled to work at the power values in different module power ranges, so that the working time of each conversion module in each module power range can be balanced, and the historical total load of each conversion module is more balanced.

Optionally, the method may further comprise the steps of:

By adopting the method, when the selected conversion module can not output the required output power, whether the sum of the maximum actual output powers of all the conversion modules which do not have faults is smaller than the current required output power or not can be further judged, and if the sum of the maximum actual output powers of the conversion modules which do not have faults is smaller than the current required output power, alarm information is sent out to enable a user to timely close the converter or control the converter to automatically stop working, so that the converter is prevented from being lost. If the sum of the maximum actual output powers of the conversion modules without faults is not less than the current required output power, the conversion module without faults with the lowest accumulated working time in the power range of each module can be further reselected to do work.

Alternatively, the above-described control method of the DC-DC converter is applicable to a unidirectional DC-DC converter as well as a bidirectional DC-DC converter. In a bidirectional DC-DC converter, the input terminals include a forward input terminal and a reverse input terminal, and the output terminals include a forward output terminal and a reverse output terminal.

Specifically, according to the forward required output power, a target number of required conversion modules and a plurality of required module power ranges are determined, and in the plurality of parallel conversion modules, the conversion module with the lowest accumulated working time in each required module power range is selected according to the target number, and the forward output power is distributed to the selected conversion module.

And determining the target quantity of the required conversion modules and the plurality of required module power ranges according to the reverse required output power, selecting the conversion module with the lowest accumulated working time length in each required module power range according to the target quantity from the plurality of parallel conversion modules, and distributing the reverse output power to the selected conversion module.

By adopting the method, the load of each conversion module in the bidirectional DC-DC converter can be more balanced regardless of whether the bidirectional DC-DC converter does work in the forward direction or in the reverse direction.

With regard to the method in the above-mentioned embodiment, the specific manner in which each step performs the operation has been described in detail in the embodiment related to the DC-DC converter, and is not described herein again.

The preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details in the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A DC-DC converter is characterized by comprising an input end, an output end, a plurality of conversion modules connected in parallel and a main control board;

the main control board is connected with each conversion module;

the main control board is used for: determining a target number of required conversion modules and a plurality of required module power ranges according to the required output power, selecting the conversion module with the lowest accumulated working time length in each required module power range according to the target number in the plurality of parallel conversion modules, and setting the power range of the selected conversion module as the corresponding required module power range;

the main control board prestores the corresponding relation between the required output power range and the number of the conversion modules and the module power range, and is used for:

2. The DC-DC converter of claim 1, wherein the main control board is configured to: detecting whether a conversion module with a fault exists in the selected conversion modules;

3. The DC-DC converter according to claim 1 or 2, wherein the DC-DC converter is a bidirectional DC-DC converter, the input terminals include a forward input terminal and a backward input terminal, and the output terminals include a forward output terminal and a backward output terminal.

4. A method for controlling a DC-DC converter, wherein the DC-DC converter includes an input terminal, an output terminal, a plurality of parallel conversion modules, and a main control board, the method comprising:

the main control board determines the target quantity of required conversion modules and a plurality of required module power ranges according to the required output power, selects the conversion module with the lowest accumulated working time length in each required module power range according to the target quantity from the plurality of parallel conversion modules, and sets the power range of the selected conversion module as the corresponding required module power range;

the main control board prestores the corresponding relation between the required output power range and the number of the conversion modules and the module power range; determining a target number of required conversion modules and a plurality of required module power ranges according to the required output power, including:

5. The method of claim 4, further comprising:

6. The method of claim 4 or 5, wherein the DC-DC converter is a bidirectional DC-DC converter, the input terminals comprise a forward input terminal and a reverse input terminal, and the output terminals comprise a forward output terminal and a reverse output terminal.