CN112305296A - Current detection method and device of DC-DC converter - Google Patents
Current detection method and device of DC-DC converter Download PDFInfo
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- CN112305296A CN112305296A CN202011298543.8A CN202011298543A CN112305296A CN 112305296 A CN112305296 A CN 112305296A CN 202011298543 A CN202011298543 A CN 202011298543A CN 112305296 A CN112305296 A CN 112305296A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/04—Measuring peak values or amplitude or envelope of ac or of pulses
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
- H02M3/1586—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel switched with a phase shift, i.e. interleaved
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention provides a current detection method and a current detection device of a DC-DC converter, which are used for determining the duty ratio of the DC-DC converter and collecting the total current by utilizing a current sensor arranged in the front position of an input end split phase of the DC-DC converter; determining the current peak value moment corresponding to each phase current of the DC-DC converter in each control period according to the duty ratio and the total current; in each control period, determining a target total current corresponding to the current peak time of each phase current in the total current; determining whether the DC-DC converter is current balanced in each control period; if not, each phase is respectively subjected to current loop control by using each peak point current in the total current. And if the DC-DC converter is not current balanced, the current loop control is performed on each phase by using the total current acquired by the acquisition, so that the circuit design difficulty and the design cost are reduced.
Description
Technical Field
The invention relates to the technical field of data processing, in particular to a current detection method and device of a DC-DC converter.
Background
In the application of the multiphase interleaving parallel DC-DC converter, the current of the DC-DC converter needs to be controlled in order to realize the multiphase interleaving parallel connection to achieve current balance.
The current of the DC-DC converter is currently controlled by: each phase of the DC-DC converter adopts a current sensor to collect current, and each phase of current is controlled by adopting an independent current loop so as to achieve the effect of current balance. However, each phase of the DC-DC converter is provided with one current sensor, and a large number of current sensors are required when the circuit of the DC-DC converter is designed, which increases the difficulty of circuit design and increases the design cost.
Disclosure of Invention
In view of this, embodiments of the present invention provide a method and an apparatus for detecting a current of a DC-DC converter, so as to solve the problems of high design difficulty and high design cost in the current control method for the DC-DC converter.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the first aspect of the embodiments of the present invention discloses a current detection method for a DC-DC converter, where the method includes:
determining the duty ratio of a DC-DC converter, and collecting the total current input into the DC-DC converter by utilizing a current sensor arranged in front of an input end split phase of the DC-DC converter;
determining a current peak value moment corresponding to each phase current of the DC-DC converter in each control period according to the duty ratio and the total current;
in each control period, determining a target total current corresponding to the current peak time of each phase current in the total current;
determining whether the DC-DC converter is current balanced by utilizing all the target total currents according to the duty ratio in each control period;
and if the DC-DC converter is not in current balance, respectively carrying out current loop control on each phase of the DC-DC converter by utilizing each peak point current in the total current.
Preferably, the duty ratio is less than 50%, and the determining whether the DC-DC converter is current balanced by using all of the target total currents according to the duty ratio in each of the control periods includes:
in each control period, if the duty ratio is less than 50%, determining the difference between every two target total currents;
if any difference value is larger than the current threshold value, determining that the DC-DC converter is not current balanced;
and if all the difference values are less than or equal to the current threshold value, determining that the current of the DC-DC converter is balanced.
Preferably, the duty ratio is greater than or equal to 50%, and the determining whether the DC-DC converter is current balanced by using all of the target total currents according to the duty ratio in each of the control periods includes:
in each control period, if the duty ratio is greater than or equal to 50%, determining whether each target total current is the same;
if each target total current is different, determining that the DC-DC converter is not current balanced;
and if each target total current is the same, determining the current balance of the DC-DC converter.
Preferably, if the DC-DC converter is not current-balanced, performing current loop control on each phase of the DC-DC converter by using each peak point current in the total current, respectively, includes:
if the DC-DC converter is not current balanced, estimating the phase current of each phase of the DC-DC converter by using each peak point current in the total current;
and respectively carrying out current loop control on each phase of the DC-DC converter by using the phase current of each phase.
Preferably, the determining the duty ratio of the DC-DC converter includes:
and calculating to obtain the corresponding Pulse Width Modulation (PWM) duty ratio by using a DC-DC converter control algorithm.
A second aspect of the embodiments of the present invention discloses a current detection device for a DC-DC converter, the device including:
the processing unit is used for determining the duty ratio of the DC-DC converter and collecting the total current input into the DC-DC converter by utilizing a current sensor arranged in a position in front of an input end split phase of the DC-DC converter;
a first determining unit, configured to determine, according to the duty ratio and the total current, a current peak time corresponding to each phase current of the DC-DC converter in each control period;
a second determining unit, configured to determine, in each of the control periods, a target total current corresponding to a current peak time of the each-phase current in the total current;
a third determining unit, configured to determine whether the DC-DC converter is current balanced by using all of the target total currents according to the duty ratio in each of the control periods;
and the control unit is used for respectively carrying out current loop control on each phase of the DC-DC converter by utilizing each peak point current in the total current if the DC-DC converter is not current balanced.
Preferably, the duty ratio is less than 50%, and the third determining unit is specifically configured to: in each control period, if the duty ratio is less than 50%, determining the difference between every two target total currents, if any difference is greater than a current threshold, determining that the current of the DC-DC converter is not balanced, and if all differences are less than or equal to the current threshold, determining that the current of the DC-DC converter is balanced.
Preferably, the duty ratio is greater than or equal to 50%, and the third determining unit is specifically configured to: in each control period, if the duty ratio is greater than or equal to 50%, determining whether each target total current is the same, if the target total currents are different, determining that the DC-DC converter is not current-balanced, and if the target total currents are the same, determining that the DC-DC converter is current-balanced.
Preferably, the control unit is specifically configured to: and if the DC-DC converter is not current balanced, estimating the phase current of each phase of the DC-DC converter by using each peak point current in the total current, and respectively performing current loop control on each phase of the DC-DC converter by using the phase current of each phase.
Preferably, the processing unit for determining the duty cycle of the DC-DC converter is specifically configured to: and calculating to obtain the corresponding Pulse Width Modulation (PWM) duty ratio by using a DC-DC converter control algorithm.
Based on the current detection method and the device of the DC-DC converter provided by the embodiment of the invention, the method comprises the following steps: determining the duty ratio of the DC-DC converter, and collecting the total current input into the DC-DC converter by using a current sensor arranged in front of an input end split phase of the DC-DC converter; determining the current peak value moment corresponding to each phase current of the DC-DC converter in each control period according to the duty ratio and the total current; in each control period, determining a target total current corresponding to the current peak time of each phase current in the total current; in each control period, determining whether the current of the DC-DC converter is balanced or not by utilizing all target total currents according to the duty ratio; and if the DC-DC converter is not balanced in current, respectively carrying out current loop control on each phase of the DC-DC converter by utilizing each peak point current in the total current. And if the DC-DC converter is not current balanced, the current loop control is performed on each phase of the DC-DC converter by using the total current acquired by the acquisition, so that the circuit design difficulty and the design cost are reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a topology diagram of a boost circuit of a DC-DC converter according to an embodiment of the present invention;
fig. 2 is a flowchart of a current detection method of a DC-DC converter according to an embodiment of the present invention;
fig. 3 is a current waveform diagram of current equalization of the DC-DC converter according to the embodiment of the present invention;
fig. 4 is another current waveform diagram for current equalization of the DC-DC converter according to the embodiment of the present invention;
fig. 5 is a current waveform diagram of a DC-DC converter provided by an embodiment of the present invention when the current is not equalized;
FIG. 6 is another current waveform diagram of the DC-DC converter of the embodiment of the present invention when it is not current balanced;
fig. 7 is a block diagram of a current detection device of a DC-DC converter according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
It can be known from the background art that, when current control is performed on a DC-DC converter, a current sensor needs to be arranged on each phase of the DC-DC converter to collect current, and each phase current is controlled independently to realize the effect of current balance, but this way increases the circuit design difficulty and design cost of the DC-DC converter.
The embodiment of the invention provides a current detection method and a current detection device for a DC-DC converter, wherein a current sensor is arranged in front of an input end phase splitting of the DC-DC converter, whether the current of the DC-DC converter is balanced is determined by only using the total current acquired by the current sensor, and if the current of the DC-DC converter is not balanced, the current loop control is performed on each phase of the DC-DC converter by using the acquired total current so as to reduce the circuit design difficulty and the design cost.
It is understood that, in the embodiment of the present invention, a current sensor is disposed before an input end of the DC-DC converter is split, and the total current (current when split is not performed) input to the DC-DC converter is collected by the current sensor, and the current detection method of the DC-DC converter provided in the embodiment of the present invention is applicable to various types of DC-DC converters, such as: the method is suitable for the multiphase interleaving parallel Buck or Boost type DC-DC converter.
For better explanation, the 2-interleaved parallel Boost circuit is exemplified as the content of "disposing a current sensor at a position before the input terminal of the DC-DC converter", and the specific content of the 2-interleaved parallel Boost circuit is shown in the Boost circuit topology of the DC-DC converter shown in fig. 1.
It is understood that, as shown in fig. 1, in the 2-phase interleaved parallel Boost circuit, the current sensor (a in fig. 1) is arranged in a position before the input end phase splitting of the DC-DC converter, and the total current of the non-phase splitting input to the DC-DC converter can be collected.
Referring to fig. 2, a flowchart of a current detection method of a DC-DC converter according to an embodiment of the present invention is shown, where the current detection method includes:
step S201: and determining the duty ratio of the DC-DC converter, and collecting the total current input into the DC-DC converter by using a current sensor arranged in a position before the input end phase splitting of the DC-DC converter.
In the process of implementing step S201 specifically, a DC-DC converter control algorithm is used to calculate and obtain a corresponding Pulse Width Modulation (PWM) duty ratio.
It should be noted that, the current sensor is disposed before the input end of the DC-DC converter, and specific contents can be referred to the contents in fig. 1 of the above embodiment of the present invention.
In a specific implementation, the current sensor is used for collecting the total current input into the DC-DC converter, and the total current is the sum of each phase current of the DC-DC converter.
Step S202: and determining the current peak value moment corresponding to each phase current of the DC-DC converter in each control period according to the duty ratio and the total current.
It can be understood that, in each control period, each phase current of the DC-DC converter has only one peak, and therefore, in the process of implementing step S202 specifically, for each control period, according to the duty ratio and the total current, a current peak time corresponding to the peak of each phase current of the DC-DC converter in the control period (a time corresponding to the peak of each phase current) is determined by using a preset algorithm.
And when the current peak value moment corresponding to the wave crest of each phase current is calculated, calculating a phase offset angle according to the staggered parallel split phase number, thereby calculating the current peak value moment of each phase current.
Such as: the DC-DC converter comprises an A-phase current and a C-phase current, and for one control period, the current peak value moment corresponding to the A-phase current in the control period is calculated and obtained by utilizing the duty ratio and the total current, and the current peak value moment corresponding to the C-phase current in the control period is calculated and obtained.
Step S203: in each control cycle, a target total current of the total currents corresponding to the current peak timing of each phase current is determined.
It will be appreciated that the current sensor is of a type which operates without interruption, i.e. the current sensor collects the total current input to the DC-DC converter without interruption.
In the process of specifically implementing step S203, for a control period, in the control period, a target total current corresponding to a current peak time of each phase current in the collected total currents is determined, that is, each current peak time corresponds to a target total current in the total currents, that is, the total current collected at each current peak time (the total current is the target total current) is obtained.
Such as: the DC-DC converter comprises an A-phase current and a C-phase current, and in a control period, the total current collected at the current peak moment of the A-phase current is obtained (the total current is the target total current at this time), and the total current collected at the current peak moment of the C-phase current is obtained (the total current is the target total current at this time).
Step S204: and in each control period, determining whether the DC-DC converter is current balanced or not by using all the target total currents according to the duty ratio. If the DC-DC converter is not current balanced, step S205 is executed. If the DC-DC converter current is balanced, the step S201 is executed to continue to collect the total current.
In the process of specifically implementing step S204, for each control period, according to the duty ratio, it is determined whether the DC-DC converter is current balanced by using all the target total currents in the control period, and if the DC-DC converter is not current balanced, current loop control is performed on each phase of the DC-DC converter, so that the DC-DC converter is current balanced. And if the current of the DC-DC converter is balanced, continuously acquiring the total current and continuously detecting whether the current of the DC-DC converter is balanced.
It can be understood that, when determining whether the DC-DC converter is current balanced, the determination manner is different according to the duty ratio, and specific determination manners are as follows.
The judgment method is as follows: in each control period, if the duty ratio is less than 50%, determining the difference (absolute value of the difference) between every two target total currents, if any difference is greater than a current threshold, determining that the current of the DC-DC converter is not balanced, and if all differences are less than or equal to the current threshold, determining that the current of the DC-DC converter is balanced.
That is, when the duty ratio is less than 50%, in each control period, the difference between every two target total currents is calculated, if all the differences are less than or equal to a current threshold (the current threshold can be determined according to the acquisition error of the current sensor), the current balance of the DC-DC converter is determined, and if any one difference is greater than the current threshold, the current balance of the DC-DC converter is determined.
To better explain the content of the first determination method, taking the example that the DC-DC converter includes 2-phase currents (a-phase current and C-phase current), the current waveform diagram of the DC-DC converter during current balancing shown in fig. 3 is taken as an example.
Fig. 3 is a current waveform diagram when the duty ratio is less than 50% and the DC-DC converter is in current balance, and fig. 3 is a waveform diagram of each phase current, a waveform diagram of each phase PWM output, and a waveform diagram of the total current in sequence from top to bottom, where 1 in the phase current waveform diagram and the PWM output waveform diagram is a waveform diagram corresponding to a, and 2 in the phase current waveform diagram and the PWM output waveform diagram is a waveform diagram corresponding to B.
It is understood that, in the phase current waveform diagram, reference numeral 1 is a current peak value of phase a in a control period, reference numeral 2 is a corresponding current peak value of phase C in the control period, and time instants corresponding to reference numerals 1 and 2 are a current peak time instant corresponding to phase a and a current peak time instant corresponding to phase C, respectively.
In the total current waveform chart, a total current (i.e., a target total current) corresponding to reference numeral 1 and a total current (i.e., a target total current) corresponding to reference numeral 2 are obtained.
As can be seen from the content shown in fig. 3, when the duty ratio is less than 50% and the DC-DC converter current is balanced, the difference between the target total current corresponding to reference numeral 1 and the target total current corresponding to reference numeral 2 is less than the current threshold.
And a second judgment mode: and in each control period, if the duty ratio is greater than or equal to 50%, determining whether each target total current is the same. And if the total target current is different, determining that the DC-DC converter is not current balanced. And if the total current of each target is the same, determining the current balance of the DC-DC converter.
That is, when the duty ratio is greater than or equal to 50%, in each control period, if all the target total currents are the same, it is determined that the current of the DC-DC converter is balanced, and if all the target total currents are different, it is determined that the current of the DC-DC converter is not balanced.
To better explain the second determination method, the DC-DC converter including 2-phase current (a-phase current and C-phase current) is taken as an example, and another current waveform diagram of the DC-DC converter during current balancing is illustrated in fig. 4.
Fig. 4 is a current waveform diagram when the DC-DC converter is in current balance with a duty ratio of 50% or more, and fig. 4 is a waveform diagram of a current of each phase, a PWM output waveform diagram of each phase, and a total current waveform diagram in the order from top to bottom, where a phase current waveform diagram and a PWM output waveform diagram are represented by a waveform diagram corresponding to reference numeral 1, and a phase current waveform diagram and a PWM output waveform diagram are represented by a waveform diagram corresponding to reference numeral 2.
It is understood that, in the phase current waveform diagram, reference numeral 1 is a current peak value of phase a in a control period, reference numeral 2 is a corresponding current peak value of phase C in the control period, and time instants corresponding to reference numerals 1 and 2 are a current peak time instant corresponding to phase a and a current peak time instant corresponding to phase C, respectively.
In the total current waveform chart, a total current (i.e., a target total current) corresponding to reference numeral 1 and a total current (i.e., a target total current) corresponding to reference numeral 2 are obtained.
As can be seen from the contents shown in fig. 4, when the duty ratio is 50% or more and the DC-DC converter currents are balanced, the target total current corresponding to reference numeral 1 is the same as the target total current corresponding to reference numeral 2.
That is, when the DC-DC converter is current-balanced, the total current is equal to the sum of the currents of each phase, and when the total current is not equal to the sum of the currents of each phase, that is, when the DC-DC converter is not current-balanced, the current loop control may be performed on the DC-DC converter, or the DC-DC converter may be stopped according to actual conditions.
Step S205: and respectively carrying out current loop control on each phase of the DC-DC converter by utilizing each peak point current in the total current.
In the process of implementing step S205 specifically, if the DC-DC converter is not current balanced, the phase current of each phase of the DC-DC converter is estimated by using each peak point current in the collected total current, and the current loop control is performed on each phase of the DC-DC converter by using the phase current of each phase.
That is, for each phase of the DC-DC converter, current loop control is performed on the phase using the estimated phase current of the phase, thereby equalizing the DC-DC converter current.
To better explain the current waveform diagram of the DC-DC converter when the DC-DC converter is not current-balanced, the current waveform diagram shown in fig. 5 and 6 is exemplified by taking the case where the DC-DC converter includes 2-phase currents (a-phase current and C-phase current).
Referring to fig. 5, a current waveform diagram of a DC-DC converter provided by the embodiment of the invention when the current is not balanced is shown.
Fig. 5 is a current waveform diagram when the duty ratio is less than 50% and the DC-DC converter is not current-balanced (a-phase current > C-phase current), fig. 5 is a waveform diagram of each phase current, a PWM output waveform diagram of each phase, and a total current waveform diagram in the order from top to bottom, where reference numeral 1 in the phase current waveform diagram and the PWM output waveform diagram is a waveform diagram corresponding to a, and reference numeral 2 in the phase current waveform diagram and the PWM output waveform diagram is a waveform diagram corresponding to B.
It is understood that, in the phase current waveform diagram, reference numeral 1 is a current peak value of phase a in a control period, reference numeral 2 is a corresponding current peak value of phase C in the control period, and time instants corresponding to reference numerals 1 and 2 are a current peak time instant corresponding to phase a and a current peak time instant corresponding to phase C, respectively.
In the total current waveform chart, a total current (i.e., a target total current) corresponding to reference numeral 1 and a total current (i.e., a target total current) corresponding to reference numeral 2 are obtained.
As can be seen from the illustration in fig. 5, in a control cycle, when the DC-DC converter is not current-balanced, the a-phase current is greater than the C-phase current, and the target total current corresponding to reference numeral 1 is greater than the target total current corresponding to reference numeral 2.
Referring to fig. 6, another current waveform diagram of the DC-DC converter provided by the embodiment of the invention when the current is not balanced is shown.
Fig. 6 is a current waveform diagram when the duty ratio is 50% or more and the DC-DC converter is not current-balanced (a-phase current > C-phase current), and fig. 6 is a waveform diagram of each phase current, a PWM output waveform diagram of each phase, and a total current waveform diagram in this order from top to bottom, where reference numeral 1 in the phase current waveform diagram and the PWM output waveform diagram is a waveform diagram corresponding to a, and reference numeral 2 in the phase current waveform diagram and the PWM output waveform diagram is a waveform diagram corresponding to B.
It is understood that, in the phase current waveform diagram, reference numeral 1 is a current peak value of phase a in a control period, reference numeral 2 is a corresponding current peak value of phase C in the control period, and time instants corresponding to reference numerals 1 and 2 are a current peak time instant corresponding to phase a and a current peak time instant corresponding to phase C, respectively.
In the total current waveform chart, a total current (i.e., a target total current) corresponding to reference numeral 1 and a total current (i.e., a target total current) corresponding to reference numeral 2 are obtained.
As can be seen from the illustration in fig. 6, when the DC-DC converter is not current-balanced in one control cycle, the a-phase current is greater than the C-phase current, and the target total current corresponding to reference numeral 1 is greater than the target total current corresponding to reference numeral 2.
In the embodiment of the invention, a current sensor is arranged in front of the input end phase splitting of the DC-DC converter, whether the current of the DC-DC converter is balanced is determined by only using the total current acquired by the current sensor, and if the current of the DC-DC converter is not balanced, the current loop control is carried out on each phase of the DC-DC converter by using the acquired total current, so that the circuit design difficulty is reduced and the design cost is reduced.
Corresponding to the current detection method of the DC-DC converter shown in the above embodiment of the present invention, referring to fig. 7, an embodiment of the present invention further provides a structural block diagram of a current detection apparatus of the DC-DC converter, where the current detection apparatus includes: a processing unit 701, a first determining unit 702, a second determining unit 703, a third determining unit 704, and a control unit 705;
and the processing unit 701 is used for determining the duty ratio of the DC-DC converter and collecting the total current input into the DC-DC converter by using a current sensor arranged in a position before the input end phase splitting of the DC-DC converter.
In a specific implementation, the processing unit 701 configured to determine a duty cycle of the DC-DC converter is specifically configured to: and calculating to obtain the corresponding PWM duty ratio by using a DC-DC converter control algorithm.
A first determining unit 702 is configured to determine a current peak time corresponding to each phase current of the DC-DC converter in each control period according to the duty ratio and the total current.
A second determining unit 703 is configured to determine, in each control cycle, a target total current corresponding to a current peak time of each phase current in the total current.
And a third determining unit 704, configured to determine whether the DC-DC converter is current balanced by using all the target total currents according to the duty ratio in each control period.
In a specific implementation, the duty ratio is less than 50%, and the third determining unit 704 is specifically configured to: and in each control period, if the duty ratio is less than 50%, determining the difference between every two target total currents, if any difference is greater than a current threshold, determining that the current of the DC-DC converter is not balanced, and if all differences are less than or equal to the current threshold, determining that the current of the DC-DC converter is balanced.
In a specific implementation, the duty ratio is greater than or equal to 50%, and the third determining unit 704 is specifically configured to: and in each control period, if the duty ratio is larger than or equal to 50%, determining whether each target total current is the same, if each target total current is different, determining that the DC-DC converter is not current balanced, and if each target total current is the same, determining that the DC-DC converter is current balanced.
And a control unit 705, configured to perform current loop control on each phase of the DC-DC converter by using each peak point current in the total current if the DC-DC converter is not current balanced.
In a specific implementation, the control unit 705 is specifically configured to: and if the DC-DC converter is not balanced in current, estimating the phase current of each phase of the DC-DC converter by using each peak point current in the total current, and respectively carrying out current loop control on each phase of the DC-DC converter by using the phase current of each phase.
In summary, embodiments of the present invention provide a method and an apparatus for detecting a current of a DC-DC converter, where a current sensor is disposed in front of an input end of the DC-DC converter, and a total current collected by only one current sensor is used to determine whether the current of the DC-DC converter is balanced, and if the current of the DC-DC converter is not balanced, the collected total current is used to perform current loop control on each phase of the DC-DC converter, so as to reduce circuit design difficulty and design cost.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method of detecting a current of a DC-DC converter, the method comprising:
determining the duty ratio of a DC-DC converter, and collecting the total current input into the DC-DC converter by utilizing a current sensor arranged in front of an input end split phase of the DC-DC converter;
determining a current peak value moment corresponding to each phase current of the DC-DC converter in each control period according to the duty ratio and the total current;
in each control period, determining a target total current corresponding to the current peak time of each phase current in the total current;
determining whether the DC-DC converter is current balanced by utilizing all the target total currents according to the duty ratio in each control period;
and if the DC-DC converter is not in current balance, respectively carrying out current loop control on each phase of the DC-DC converter by utilizing each peak point current in the total current.
2. The method of claim 1, wherein the duty cycle is less than 50%, and wherein determining whether the DC-DC converter is current balanced with all of the target total currents according to the duty cycle in each of the control periods comprises:
in each control period, if the duty ratio is less than 50%, determining the difference between every two target total currents;
if any difference value is larger than the current threshold value, determining that the DC-DC converter is not current balanced;
and if all the difference values are less than or equal to the current threshold value, determining that the current of the DC-DC converter is balanced.
3. The method of claim 1, wherein the duty ratio is greater than or equal to 50%, and wherein the determining whether the DC-DC converter is current balanced with all of the target total currents according to the duty ratio in each of the control periods comprises:
in each control period, if the duty ratio is greater than or equal to 50%, determining whether each target total current is the same;
if each target total current is different, determining that the DC-DC converter is not current balanced;
and if each target total current is the same, determining the current balance of the DC-DC converter.
4. The method of claim 1, wherein the separately performing current loop control on each phase of the DC-DC converter using each peak point current in the total current if the DC-DC converter is not current balanced comprises:
if the DC-DC converter is not current balanced, estimating the phase current of each phase of the DC-DC converter by using each peak point current in the total current;
and respectively carrying out current loop control on each phase of the DC-DC converter by using the phase current of each phase.
5. The method of claim 1, wherein determining the duty cycle of the DC-DC converter comprises:
and calculating to obtain the corresponding Pulse Width Modulation (PWM) duty ratio by using a DC-DC converter control algorithm.
6. A current detection device of a DC-DC converter, the device comprising:
the processing unit is used for determining the duty ratio of the DC-DC converter and collecting the total current input into the DC-DC converter by utilizing a current sensor arranged in a position in front of an input end split phase of the DC-DC converter;
a first determining unit, configured to determine, according to the duty ratio and the total current, a current peak time corresponding to each phase current of the DC-DC converter in each control period;
a second determining unit, configured to determine, in each of the control periods, a target total current corresponding to a current peak time of the each-phase current in the total current;
a third determining unit, configured to determine whether the DC-DC converter is current balanced by using all of the target total currents according to the duty ratio in each of the control periods;
and the control unit is used for respectively carrying out current loop control on each phase of the DC-DC converter by utilizing each peak point current in the total current if the DC-DC converter is not current balanced.
7. The apparatus according to claim 6, wherein the duty cycle is less than 50%, and the third determining unit is specifically configured to: in each control period, if the duty ratio is less than 50%, determining the difference between every two target total currents, if any difference is greater than a current threshold, determining that the current of the DC-DC converter is not balanced, and if all differences are less than or equal to the current threshold, determining that the current of the DC-DC converter is balanced.
8. The apparatus according to claim 6, wherein the duty cycle is greater than or equal to 50%, and the third determining unit is specifically configured to: in each control period, if the duty ratio is greater than or equal to 50%, determining whether each target total current is the same, if the target total currents are different, determining that the DC-DC converter is not current-balanced, and if the target total currents are the same, determining that the DC-DC converter is current-balanced.
9. The apparatus according to claim 6, wherein the control unit is specifically configured to: and if the DC-DC converter is not current balanced, estimating the phase current of each phase of the DC-DC converter by using each peak point current in the total current, and respectively performing current loop control on each phase of the DC-DC converter by using the phase current of each phase.
10. The apparatus according to claim 6, wherein the processing unit configured to determine a duty cycle of a DC-DC converter is specifically configured to: and calculating to obtain the corresponding Pulse Width Modulation (PWM) duty ratio by using a DC-DC converter control algorithm.
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