CN108155795B - Electric vehicle, DC-DC converter thereof and control method of DC-DC converter - Google Patents

Electric vehicle, DC-DC converter thereof and control method of DC-DC converter Download PDF

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Publication number
CN108155795B
CN108155795B CN201611099657.3A CN201611099657A CN108155795B CN 108155795 B CN108155795 B CN 108155795B CN 201611099657 A CN201611099657 A CN 201611099657A CN 108155795 B CN108155795 B CN 108155795B
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mode
bridge
control
switching tube
total time
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CN108155795A (en
Inventor
张妮
王兴辉
王超
沈晓峰
邬白贺
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BYD Co Ltd
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BYD Co Ltd
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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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/3353—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter

Abstract

The invention discloses an electric automobile, a DC-DC converter thereof and a control method of the DC-DC converter, wherein the DC-DC converter comprises an H bridge, the H bridge comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, and the control method comprises the following steps: in the whole life cycle of the DC-DC converter, a control mode of phase shift modulation and a control mode of lower tube modulation are alternately carried out, when the control mode of phase shift modulation is adopted, the H bridge is controlled in a first mode or a second mode based on total time TA and total time TB, and when the control mode of lower tube modulation is adopted, the H bridge is controlled in a third mode or a fourth mode based on total time TC and total time TD, so that the first switching tube, the second switching tube, the third switching tube and the fourth switching tube are subjected to temperature equalization control, the heating of the first switching tube to the fourth switching tube in the H bridge is relatively balanced, and the service life of the switching tubes in the H bridge is prolonged.

Description

Electric vehicle, DC-DC converter thereof and control method of DC-DC converter
Technical Field
The invention relates to the technical field of electric automobiles, in particular to a control method of a DC-DC converter, the DC-DC converter and an electric automobile.
Background
The DC-DC converter has been an important component in the field of power electronics, and along with the development of electric vehicle commercialization, the DC-DC converter has also become one of important parts of electric vehicles. The topology of the DC-DC converter is many, and in the medium and large power field, the full-bridge PWM converter is the most used topology.
The full-bridge PWM converter has many control modes, and the related art mostly adopts a phase-shift modulation control mode and a low-tube modulation control mode. However, when the phase shift modulation control mode is adopted, the leading arm is easy to realize soft switching, and the lagging arm is not easy to realize soft switching, so that the lagging arm is more serious in heat generation than the leading arm; when the control mode of the lower tube modulation is adopted, the upper tube is easy to realize soft switching, and the lower tube is not easy to realize soft switching, so that the lower tube generates heat more seriously than the upper tube.
Therefore, the above two control modes can cause the serious problem of heating of the switch tube, and the service life of the switch 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 method for controlling a DC-DC converter, which can relatively balance the heat generation of the first to fourth switching tubes in the H-bridge and improve the operating life of the switching tubes in the H-bridge.
A second object of the present invention is to provide a DC-DC converter. The third purpose of the invention is to provide an electric automobile.
In order to achieve the above object, an embodiment of an aspect of the present invention provides a control method of a DC-DC converter, where the DC-DC converter includes an H-bridge, and the H-bridge includes a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube, where the first switching tube and the second switching tube form a first bridge arm, and the third switching tube and the fourth switching tube form a second bridge arm, and the control method includes the following steps: when the DC-DC converter works, acquiring a control mode of the DC-DC converter during last working, and selecting the control mode during the current working according to the control mode of the DC-DC converter during the last working, wherein the control mode of the DC-DC converter comprises a phase-shift modulation control mode and a lower tube modulation control mode; when the control mode of the current work is selected to be the phase shift modulation control mode, acquiring total time TA for controlling the H bridge in a first mode and total time TB for controlling the H bridge in a second mode, and selecting the mode of controlling the H bridge by judging the relation between the total time TA and the total time TB to perform temperature balance control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, wherein when the H bridge is controlled in the first mode, the first bridge arm is used as an advance bridge arm, and the second bridge arm is used as a delay bridge arm; when the H bridge is controlled in the second mode, the second bridge arm is used as an advanced bridge arm, and the first bridge arm is used as a delayed bridge arm; when the control mode of the current work is selected to be the control mode of the lower tube modulation, acquiring total time TC for controlling the H bridge in a third mode and total time TD for controlling the H bridge in a fourth mode, and selecting the mode of controlling the H bridge by judging the relation between the total time TC and the total time TD so as to perform temperature equalization control on the first switching tube, the second switching tube, the third switching tube and the fourth switching tube, wherein when the H bridge is controlled in the third mode, the first switching tube and the third switching tube are used as upper tubes, the second switching tube and the fourth switching tube are used as lower tubes, and the control mode of the lower tube modulation is adopted to control the first switching tube to the fourth switching tube; and when the H bridge is controlled in the fourth mode, the first switching tube and the third switching tube are used as a lower tube, the second switching tube and the fourth switching tube are used as an upper tube, and the first switching tube to the fourth switching tube are controlled in a control mode of lower tube modulation.
According to the control method of the DC-DC converter, when the DC-DC converter works, the control mode of the DC-DC converter in the last working process is obtained, and the control mode in the current working process is selected according to the control mode of the DC-DC converter in the last working process, so that the control mode of phase shift modulation and the control mode of lower tube modulation in the whole life cycle of the DC-DC converter are alternately carried out. When the control mode of the current work is selected to be a phase shift modulation control mode, acquiring total time TA for controlling the H bridge in a first mode and total time TB for controlling the H bridge in a second mode, then judging the relation between the total time TA and the total time TB, and finally selecting a mode for controlling the H bridge according to the relation between the total time TA and the total time TB so as to perform temperature equalization control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube; when the control mode in the current work is selected to be a down tube modulation control mode, acquiring total time TC for controlling the H bridge in a third mode and total time TD for controlling the H bridge in a fourth mode, then judging the relation between the total time TC and the total time TD, finally selecting a mode for controlling the H bridge according to the relation between the total time TC and the total time TD, and performing temperature equalization control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, so that the total time TA and the total time TB are as equal as possible when the DC-DC converter adopts a phase-shifting modulation control mode in the whole life cycle, the total time TC and the total time TD are as equal as possible when the DC-DC converter adopts the down tube modulation control mode, the heating of each switch tube is relatively balanced, the working life of the H bridge switch tubes is prolonged under the condition of not increasing the cost, thereby the life cycle of the DC-DC converter can be extended.
In order to achieve the above object, according to another embodiment of the present invention, a DC-DC converter includes: the bridge comprises an H bridge and a bridge body, wherein the H bridge comprises a first switching tube, a second switching tube, a third switching tube and a fourth switching tube, the first switching tube and the second switching tube form a first bridge arm, and the third switching tube and the fourth switching tube form a second bridge arm; a control module, configured to obtain a control manner of the DC-DC converter during last operation when the DC-DC converter operates, and select a control manner of the DC-DC converter during the last operation according to the control manner of the DC-DC converter during the last operation, where the control manner of the DC-DC converter includes a control manner of phase shift modulation and a control manner of down tube modulation, and when the control manner of the current operation is selected as the control manner of phase shift modulation, the control module obtains a total time TA for controlling the H-bridge in a first manner and a total time TB for controlling the H-bridge in a second manner, and selects a manner of controlling the H-bridge by determining a relationship between the total time TA and the total time TB to perform temperature equalization control on the first switching tube, the second switching tube, the third switching tube, and the fourth switching tube, when the H bridge is controlled in the first mode, the first bridge arm is used as a leading bridge arm, and the second bridge arm is used as a lagging bridge arm; when the H bridge is controlled in the second mode, the second bridge arm is used as an advanced bridge arm, and the first bridge arm is used as a delayed bridge arm; when the control mode of the current work is selected to be the control mode of the lower tube modulation, the control module obtains total time TC for controlling the H bridge in a third mode and total time TD for controlling the H bridge in a fourth mode, and selects the mode of controlling the H bridge by judging the relation between the total time TC and the total time TD so as to perform temperature equalization control on the first switching tube, the second switching tube, the third switching tube and the fourth switching tube, wherein when the H bridge is controlled in the third mode, the first switching tube and the third switching tube are used as upper tubes, the second switching tube and the fourth switching tube are used as lower tubes, and the control mode of the lower tube modulation is adopted to control the first switching tube to the fourth switching tube; and when the H bridge is controlled in the fourth mode, the first switching tube and the third switching tube are used as a lower tube, the second switching tube and the fourth switching tube are used as an upper tube, and the first switching tube to the fourth switching tube are controlled in a control mode of lower tube modulation.
According to the DC-DC converter provided by the embodiment of the invention, when the DC-DC converter is started to work, the control mode of the DC-DC converter in the last working is obtained through the control module, and the control mode in the current working is selected according to the control mode of the DC-DC converter in the last working, so that the control mode of phase shift modulation and the control mode of lower tube modulation are alternately carried out in the whole life cycle of the DC-DC converter. When the control mode during the work is selected to be a phase shift modulation control mode, acquiring total time TA for controlling the H bridge in a first mode and total time TB for controlling the H bridge in a second mode through a control module, then judging the relation between the total time TA and the total time TB, and finally selecting a mode for controlling the H bridge according to the relation between the total time TA and the total time TB so as to perform temperature balance control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube; when the control mode of the current work is selected to be the control mode of the lower tube modulation, the total time TC for controlling the H bridge in the third mode and the total time TD for controlling the H bridge in the fourth mode are obtained through the control module, then judging the relation between the total time TC and the total time TD, finally selecting the mode of controlling the H bridge according to the relation between the total time TC and the total time TD, so as to carry out temperature equalization control on the first switching tube, the second switching tube, the third switching tube and the fourth switching tube, therefore, in the whole life cycle, the total time TA and the total time TB when the control mode of phase shift modulation is adopted are equal as much as possible, the total time TC and the total time TD when the control mode of lower tube modulation is adopted are equal as much as possible, so that the heat generation of each switching tube is relatively balanced, under the condition of not increasing the cost, the service life of the switching tube in the H bridge is prolonged, so that the life cycle can be prolonged.
In addition, the embodiment of the invention also provides an electric automobile which comprises the DC-DC converter.
The electric automobile provided by the embodiment of the invention can control the DC-DC converter to alternately perform a phase-shift modulation control mode and a lower tube modulation control mode in the whole life cycle, the total time TA and the total time TB when the phase-shift modulation control mode is adopted are equal to the greatest extent, and the total time TC and the total time TD when the lower tube modulation control mode is adopted are equal to the greatest extent, so that the temperature balance control of the first switching tube, the second switching tube, the third switching tube and the fourth switching tube in the H bridge can be realized, the heating of each switching tube is relatively balanced, the working life of the switching tubes in the H bridge is prolonged under the condition of not increasing the cost, and the life cycle of the DC-DC converter is prolonged.
Drawings
FIG. 1 is a circuit schematic of a DC-DC converter according to one embodiment of the present invention;
fig. 2 is a flowchart of a control method of a DC-DC converter according to an embodiment of the present invention;
fig. 3A is a schematic diagram of driving waveforms of four switching tubes when an H-bridge is controlled by a first manner according to an embodiment of the present invention;
fig. 3B is a schematic diagram of driving waveforms of four switching tubes when an H-bridge is controlled by a second method according to an embodiment of the present invention;
fig. 4A is a schematic diagram of driving waveforms of four switching tubes when an H-bridge is controlled by a third method according to an embodiment of the present invention;
fig. 4B is a schematic diagram of driving waveforms of four switching tubes when an H-bridge is controlled by a fourth method according to an embodiment of the present invention;
FIG. 5 is a flow chart of a method of controlling a DC-DC converter according to an embodiment of the present invention;
fig. 6 is a block diagram schematically illustrating an electric vehicle according to an embodiment of the present 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 DC-DC converter, and an electric vehicle having the DC-DC converter according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in fig. 1, the DC-DC converter according to an embodiment of the present invention includes an H-bridge, which may include a first switching tube Q1, a second switching tube Q2, a third switching tube Q3, and a fourth switching tube Q4. The first switching tube Q1 and the second switching tube Q2 form a first bridge arm, the third switching tube Q3 and the fourth switching tube Q4 form a second bridge arm, a first node a is arranged between the first switching tube Q1 and the second switching tube Q2, and a second node B is arranged between the third switching tube Q3 and the fourth switching tube Q4.
As shown in fig. 1, the DC-DC converter further includes a transformer, a first inductor L1, a first capacitor C1, a second inductor L2, a second capacitor C2, a fifth switch Q5, and a sixth switch Q6, wherein one end of the first inductor L1 is connected to the first node a, the other end of the first inductor L1 is connected to one end of the first capacitor C1, the other end of the first capacitor C1 is connected to one end of a primary winding of the transformer, and the other end of the primary winding of the transformer is connected to the second node B. The secondary winding of the transformer is respectively connected with a fifth switching tube Q5 and a sixth switching tube Q6, and a second inductor L2 and a second capacitor C2 are connected at the output end of the DC-DC converter.
In an embodiment of the present invention, as shown in fig. 2, the control method of the DC-DC converter includes the following steps:
and S1, when the DC-DC converter works, acquiring the control mode of the DC-DC converter during the last working, and selecting the control mode during the current working according to the control mode of the DC-DC converter during the last working, wherein the control mode of the DC-DC converter comprises a phase-shift modulation control mode and a lower tube modulation control mode.
That is, each time the DC-DC converter starts to operate, the control mode adopted last time is read, and if the control mode adopted last time operation is the control mode of phase shift modulation, the control mode of lower tube modulation is adopted in the current operation of the DC-DC converter; if the control mode adopted by the last work is the control mode of the lower tube modulation, the DC-DC converter adopts the control mode of the phase shift modulation in the work. Thus, the control mode of the phase shift modulation and the control mode of the lower tube modulation are alternately performed in the whole life cycle of the DC-DC converter.
And S2, when the control mode during the work is selected to be the phase shift modulation control mode, acquiring the total time TA for controlling the H bridge in the first mode and the total time TB for controlling the H bridge in the second mode, and selecting the mode for controlling the H bridge by judging the relation between the total time TA and the total time TB so as to perform temperature equalization control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube.
When the H bridge is controlled in the first mode, the first bridge arm is used as a leading bridge arm, and the second bridge arm is used as a lagging bridge arm; and when the H bridge is controlled in the second mode, taking the second bridge arm as a leading bridge arm and taking the first bridge arm as a lagging bridge arm.
According to an embodiment of the present invention, when the H-bridge is controlled in the first manner, the control signal output to the first switch Q1 is complementary to the control signal output to the second switch Q2, and the control signal output to the third switch Q3 is complementary to the control signal output to the fourth switch Q4, and the first switch Q1 is turned on one phase angle ahead of the fourth switch Q4, and the second switch Q2 is turned on one phase angle ahead of the third switch Q3.
Specifically, the driving waveform of the first switch tube Q1 and the driving waveform of the second switch tube Q2The dynamic waveform, the driving waveform of the third switching tube Q3, the driving waveform of the fourth switching tube Q4 and the voltage U between two bridge arms of the H bridgeABThe waveform is shown in fig. 3A. As can be seen from fig. 3A, the control signals of Q1 and Q2 of the four switching tubes of the H-bridge are complementary, the control signals of Q3 and Q4 are complementary, the diagonal switching tube Q1 is turned on one phase angle before Q4, and Q2 is turned on one phase angle before Q3. And the output voltage is adjusted by adjusting the magnitude of the phase angle.
When the H-bridge is controlled in the second mode, the control signal output to the first switching tube Q1 is complementary to the control signal output to the second switching tube Q2, and the control signal output to the third switching tube Q3 is complementary to the control signal output to the fourth switching tube Q4, and the fourth switching tube Q4 is turned on one phase angle ahead of the first switching tube Q1, and the third switching tube Q3 is turned on one phase angle ahead of the second switching tube Q2.
Specifically, the driving waveform of the first switching tube Q1, the driving waveform of the second switching tube Q2, the driving waveform of the third switching tube Q3, the driving waveform of the fourth switching tube Q4 and the voltage U between the two legs of the H-bridgeABThe waveform is shown in fig. 3B. It can be seen from fig. 4 that the control signals of Q1 and Q2 of the four switching tubes of the H-bridge are complementary, the control signals of Q3 and Q4 are complementary, the diagonal switching tube Q4 is turned on one phase angle before Q1, and Q3 is turned on one phase angle before Q2. Likewise, the output voltage is adjusted by adjusting the magnitude of the phase angle.
It should be noted that, in the operation process of the DC-DC converter using the phase shift modulation control method, if the H-bridge is controlled only by the first method a, it is difficult to realize soft switching, i.e., zero-voltage switching, as the switching tubes Q3 and Q4 in the hysteresis bridge arm, and therefore, the switching losses of the switching tubes Q3 and Q4 are large, which causes overheating.
Similarly, in the operation of the DC-DC converter using the phase shift modulation control method, if the H-bridge is controlled only by the second method B, it is difficult to realize soft switching, i.e., zero-voltage switching, of the switching tubes Q1 and Q2 in the hysteresis bridge arm, and therefore, the switching losses of the switching tubes Q1 and Q2 are large, which causes overheating.
Therefore, in an embodiment of the present invention, when the DC-DC converter operates in a phase shift modulation control manner and the H-bridge is controlled in the first manner a, the time for controlling the H-bridge in the first manner a is recorded, so that the total time TA for controlling the H-bridge in the first manner can be obtained and then stored; and when the H bridge is controlled by the second mode B, recording the time for controlling the H bridge by the second mode B, thereby obtaining the total time TB for controlling the H bridge by the second mode, and then storing the total time TB. Therefore, when the DC-DC converter works in a phase-shift modulation control mode each time, the relation between the total time TA and the total time TB is judged, and the mode for controlling the H bridge is selected according to the relation between the total time TA and the total time TB, so that the temperature balance control of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube can be realized.
Selecting a mode for controlling the H-bridge according to the relationship between the total time TA and the total time TB, specifically including: when the total time TA is greater than the total time TB, selecting the second mode to control the H bridge; when the total time TA is less than the total time TB, selecting the first mode to control the H bridge; and when the total time TA is equal to the total time TB, selecting the first mode or the second mode to control the H bridge.
That is, before the DC-DC converter starts operating in the phase shift modulation control mode, the total time TA for controlling the H-bridge in the first mode and the total time TB for controlling the H-bridge in the second mode are acquired from the storage area, and then the total time TA and the total time TB are determined, and it is determined whether to control the H-bridge in the first mode or to control the H-bridge in the second mode according to the determination result. For example, when the DC-DC converter works in the first mode to control the H bridge, the total time recorded when the DC-DC converter stops working is the sum of the total time obtained from the storage area when the work starts and the work time, namely the total time needs to be updated after the DC-DC converter works every time, so that the H bridge can be conveniently controlled by selecting which mode to work next time.
It should be noted that, in the embodiment of the present invention, the DC-DC converter adopts a control method of phase shift modulation regardless of whether the H-bridge is controlled in the first manner or the H-bridge is controlled in the second manner. The first to fourth switching tubes are driven by 50% duty ratio, the driving voltages of the same bridge arm are complementary, the phase difference is 180 degrees, the phase difference between the leading bridge arm and the lagging bridge arm is a phase angle, and the output voltage is adjusted by adjusting the phase angle.
In summary, when the DC-DC converter operates in the phase shift modulation control mode, the H-bridge is controlled by recording whether the DC-DC converter adopts the first mode or the second mode, recording the total time TA when the DC-DC converter adopts the first mode and the total time TB when the DC-DC converter adopts the second mode, and then determining the relationship between TA and TB, so as to select the mode of controlling the H-bridge, and it is possible to achieve the relative balance of the heat generation amounts of the switching tubes Q1, Q2, Q3, and Q4 in the H-bridge in the phase shift modulation control mode of the DC-DC converter, so that additional components are not required to be added, the cost is reduced, the service life of the DC-DC converter can be increased, and the failure rate is reduced.
And S3, when the control mode in the work is selected to be a lower tube modulation control mode, acquiring the total time TC for controlling the H bridge in a third mode and the total time TD for controlling the H bridge in a fourth mode, and selecting the mode for controlling the H bridge by judging the relation between the total time TC and the total time TD so as to perform temperature equalization control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube.
When the H-bridge is controlled in the third mode, the first switching tube Q1 and the third switching tube Q3 are used as upper tubes, the second switching tube Q2 and the fourth switching tube Q4 are used as lower tubes, and the first switching tube to the fourth switching tube are controlled in a lower tube modulation control mode; when the H-bridge is controlled in the fourth mode, the first switching tube Q1 and the third switching tube Q3 are used as a lower tube, the second switching tube Q2 and the fourth switching tube Q4 are used as an upper tube, and the first switching tube to the fourth switching tube are controlled in a control mode of lower tube modulation.
According to an embodiment of the present invention, when the H-bridge is controlled in the third manner, the control signal output to the first switching transistor Q1 is complementary to the control signal output to the third switching transistor Q3 and has a fixed duty ratio, and the falling edges of the control signals output to the second switching transistor Q2 and the fourth switching transistor Q4 are PWM controlled.
Specifically, the driving waveform of the first switching tube Q1, the driving waveform of the second switching tube Q2, the driving waveform of the third switching tube Q3, the driving waveform of the fourth switching tube Q4 and the voltage U between the two legs of the H-bridgeABThe waveform is shown in fig. 4A. As can be seen from fig. 4A, the control signals of Q1 and Q3 in the four switching tubes of the H-bridge are complementary and have a fixed 50% duty cycle, the falling edges of Q2 and Q4 are modulated according to the PWM rule, and the output voltage is adjusted by adjusting the falling edge of the driving voltage of the lower tube.
When the H-bridge is controlled in the fourth mode, the control signal output to the second switching transistor Q2 is complementary to the control signal output to the fourth switching transistor Q4, has a fixed duty ratio, and the falling edges of the control signals output to the first switching transistor Q1 and the third switching transistor Q3 are PWM controlled.
Specifically, the driving waveform of the first switching tube Q1, the driving waveform of the second switching tube Q2, the driving waveform of the third switching tube Q3, the driving waveform of the fourth switching tube Q4 and the voltage U between the two legs of the H-bridgeABThe waveform is shown in fig. 4B. As can be seen from fig. 4B, the control signals of Q2 and Q4 in the four switching tubes of the H-bridge are complementary and have a fixed 50% duty cycle, the falling edges of Q1 and Q3 are modulated according to the PWM rule, and the output voltage is adjusted by adjusting the falling edge of the driving voltage of the lower tube.
It should be noted that, in the working process of the DC-DC converter using the control method of the down tube modulation, if the H-bridge is controlled only by the third method C, since only the primary side resonant inductor can be used in the resonant discharge stage, it is difficult to realize soft switching, i.e., zero voltage switching, for the switching tubes Q2 and Q4 of the down tube, so that the switching losses of the switching tubes Q2 and Q4 are large, which causes overheating.
Similarly, in the operation process of the DC-DC converter using the down tube modulation control method, if the H-bridge is controlled only by the fourth method D, since only the primary side resonant inductor can be utilized in the resonant discharge stage, the switching tubes Q1 and Q3 as the down tubes are difficult to realize soft switching, i.e., zero voltage switching, and thus the switching losses of the switching tubes Q1 and Q3 are large, which leads to overheating.
Therefore, in an embodiment of the present invention, when the DC-DC converter operates in the down tube modulation control mode and the H-bridge is controlled in the third mode C, the time for controlling the H-bridge in the third mode C is recorded, so that the total time TC for controlling the H-bridge in the third mode can be obtained and then stored; when the H bridge is controlled by the fourth mode D, the time for controlling the H bridge by the fourth mode D is recorded, so that the total time TD for controlling the H bridge by the fourth mode can be obtained and then stored. Therefore, when the DC-DC converter works in a control mode of lower tube modulation each time, the relation between the total time TC and the total time TD is judged, and the mode of controlling the H bridge is selected according to the relation between the total time TC and the total time TD, so that the temperature balance control of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube can be realized.
Selecting a mode for controlling the H bridge according to the relation between the total time TC and the total time TD, specifically comprising: when the total time TC is greater than the total time TD, selecting the fourth mode to control the H bridge; when the total time TC is smaller than the total time TD, selecting the third mode to control the H bridge; and when the total time TC is equal to the total time TD, selecting the third mode or the fourth mode to control the H bridge.
That is, before the DC-DC converter starts operating in the down tube modulation control mode, the total time TC for controlling the H-bridge in the third mode and the total time TD for controlling the H-bridge in the fourth mode are acquired from the storage area, and then the total time TC and the total time TD are determined, and it is determined whether to control the H-bridge in the third mode or to control the H-bridge in the fourth mode according to the determination result. For example, when the DC-DC converter works in the third mode to control the H bridge, the total time recorded when the DC-DC converter stops working is the sum of the total time obtained from the storage area when the work is started and the work time, namely the total time needs to be updated after the DC-DC converter works every time, so that the H bridge can be conveniently controlled by selecting which mode to work next time.
In the embodiment of the present invention, the DC-DC converter adopts the control method of the down tube modulation regardless of whether the H-bridge is controlled in the third manner or the fourth manner. When the control mode of the lower tube modulation is adopted, the two switching tubes of the upper tube are alternately switched on according to the 50% duty ratio without dead time, and the regulation of the output voltage is realized by regulating the falling edges of the driving voltage of the two switching tubes of the lower tube.
In the control mode of the lower tube modulation, the two switching tubes of the upper tube are easy to realize soft switching, i.e. zero voltage switching, corresponding to the leading bridge arm in the control mode of the phase shift modulation, while the two switching tubes of the lower tube are corresponding to the lagging bridge arm in the control mode of the phase shift modulation, so that zero voltage switching is difficult to realize.
In the embodiment of the invention, when the DC-DC converter adopts a control mode of lower tube modulation in the whole life cycle, the first to fourth switching tubes can be alternately used as the upper tube and the lower tube, namely Q1, Q3, Q2 and Q4 are alternately used as the upper tube and the lower tube, so that the temperature stress is effectively and uniformly distributed in the four switching tubes of the H bridge, the heat generation of each switching tube is relatively balanced, the integral heat balance is realized, and the service life of the DC-DC converter is prolonged.
In summary, when the DC-DC converter operates in the down tube modulation control manner, the H-bridge is controlled by recording whether the DC-DC converter employs the third manner or the fourth manner, recording the total time TC when the DC-DC converter employs the third manner and the total time TD when the DC-DC converter employs the fourth manner, and then determining the relationship between TC and TD, so as to select the H-bridge control manner, and it is possible to achieve a relative balance of the heat generation amounts of the switching tubes Q1, Q2, Q3, and Q4 in the H-bridge in the DC-DC converter employing the down tube modulation control manner, so that additional components do not need to be added, the cost is reduced, the operating life of the DC-DC converter can be increased, and the failure rate is reduced.
Specifically, according to an embodiment of the present invention, as shown in fig. 5, the control method of the DC-DC converter includes the following steps:
s501, when the DC-DC converter starts to work, a control waveform needs to be output to control a switching tube in an H bridge.
S5011, reading a control mode adopted by the DC-DC converter in the last working.
S5011, determining whether the control mode of phase shift modulation was used last time. If yes, go to step S517; if not, step S502 is performed.
That is, if the control mode adopted in the last operation is the phase shift modulation control mode, the DC-DC converter will adopt the control mode of the lower tube modulation in the current operation; if the control mode adopted by the last work is not the phase-shift modulation control mode, the DC-DC converter adopts the phase-shift modulation control mode in the work.
And S502, reading the total time TA for controlling the H bridge in the first mode A and the total time TB for controlling the H bridge in the second mode B.
S503, judging whether TA is larger than TB. If yes, go to step S504; if not, step S508 is performed.
And S504, selecting the second mode B to control the H bridge.
And S505, the DC-DC converter is in the working process.
And S506, judging whether the working process of the DC-DC converter is finished or not. If yes, go to step S507; if not, return to step S505.
And S507, recording the current working time of the DC-DC converter, and updating the total time TB according to the total time TB acquired from the storage area when the current working of the DC-DC converter is started and the current working time.
S508, judging whether TA is smaller than TB. If yes, go to step S509; if not, step S513 is executed.
And S509, selecting the first mode A to control the H bridge.
And S510, the DC-DC converter is in the working process.
And S511, judging whether the working process of the DC-DC converter is finished or not. If yes, go to step S512; if not, return to step S510.
S512, recording the current working time of the DC-DC converter, and updating the total time TA according to the total time TA acquired from the storage area when the current working of the DC-DC converter is started and the current working time.
And S513, selecting the first mode A or the second mode B to control the H bridge.
And S514, the DC-DC converter is in the working process.
And S515, judging whether the working process of the DC-DC converter is finished or not. If yes, go to step S516; if not, return to step S514.
And S516, recording the current working time of the DC-DC converter. If the first mode A is selected to control the H bridge, updating the total time TA according to the total time TA acquired from the storage area when the DC-DC converter starts working at this time and the working time at this time; and if the second mode B is selected to control the H bridge, updating the total time TB according to the total time TB acquired from the storage area when the DC-DC converter starts to work at this time and the working time at this time.
And S517, reading the total time TC for controlling the H bridge in the third mode C and the total time TD for controlling the H bridge in the fourth mode D.
S518, judging whether TC is larger than TD. If so, go to step S519; if not, step S523 is performed.
And S519, selecting the fourth mode D to control the H bridge.
And S520, the DC-DC converter is in the working process.
And S521, judging whether the working process of the DC-DC converter is finished or not. If yes, go to step S522; if not, return to step S520.
And S522, recording the current working time of the DC-DC converter, and updating the total time TD according to the total time TD acquired from the storage area when the current working of the DC-DC converter is started and the current working time.
S523, judging whether TC is smaller than TD. If yes, go to step S524; if not, step S528 is performed.
And S524, selecting the third mode C to control the H bridge.
And S525, the DC-DC converter is in the working process.
And S526, judging whether the working process of the DC-DC converter is finished or not. If yes, go to step S527; if not, return to step S525.
And S527, recording the current working time of the DC-DC converter, and updating the total time TC according to the total time TC obtained from the storage area when the current working of the DC-DC converter starts and the current working time.
And S528, selecting the third mode C or the fourth mode D to control the H bridge.
And S529, the DC-DC converter is in the working process.
And S530, judging whether the working process of the DC-DC converter is finished or not. If yes, go to step S531; if not, return to step S529.
And S531, recording the working time of the DC-DC converter. If the third mode C is selected to control the H bridge, updating the total time TC according to the total time TC acquired from the storage area when the DC-DC converter starts working at this time and the working time at this time; and if the fourth mode D is selected to control the H bridge, updating the total time TD according to the total time TD acquired from the storage area when the DC-DC converter starts to work at this time and the working time at this time.
Therefore, in the embodiment of the invention, the control mode of the phase shift modulation and the control mode of the down tube modulation are alternately carried out in the whole life cycle of the DC-DC converter, and selects to control the H-bridge in the first or second way based on the total time TA and the total time TB when the control mode of phase shift modulation is adopted, and selecting to control the H-bridge in the third or fourth way based on the total time TC and the total time TD when the control mode of the down tube modulation is adopted, therefore, in the whole life cycle, the total time TA and the total time TB of the DC-DC converter adopting a phase-shift modulation control mode are equal to the greatest extent, and the total time TC and the total time TD of the DC-DC converter adopting a lower tube modulation control mode are equal to the greatest extent, so that the heating of each switching tube is relatively balanced, and the service life of the DC-DC converter is greatly prolonged.
According to the control method of the DC-DC converter, when the DC-DC converter works, the control mode of the DC-DC converter in the last working process is obtained, and the control mode in the current working process is selected according to the control mode of the DC-DC converter in the last working process, so that the control mode of phase shift modulation and the control mode of lower tube modulation in the whole life cycle of the DC-DC converter are alternately carried out. When the control mode of the current work is selected to be a phase shift modulation control mode, acquiring total time TA for controlling the H bridge in a first mode and total time TB for controlling the H bridge in a second mode, then judging the relation between the total time TA and the total time TB, and finally selecting a mode for controlling the H bridge according to the relation between the total time TA and the total time TB so as to perform temperature equalization control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube; when the control mode in the current work is selected to be a down tube modulation control mode, acquiring total time TC for controlling the H bridge in a third mode and total time TD for controlling the H bridge in a fourth mode, then judging the relation between the total time TC and the total time TD, finally selecting a mode for controlling the H bridge according to the relation between the total time TC and the total time TD, and performing temperature equalization control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, so that the total time TA and the total time TB are as equal as possible when the DC-DC converter adopts a phase-shifting modulation control mode in the whole life cycle, the total time TC and the total time TD are as equal as possible when the DC-DC converter adopts the down tube modulation control mode, the heating of each switch tube is relatively balanced, the working life of the H bridge switch tubes is prolonged under the condition of not increasing the cost, thereby the life cycle of the DC-DC converter can be extended.
As shown in fig. 1, the DC-DC converter according to an embodiment of the present invention includes an H-bridge and a Control module 100, such as an MCU (Micro Control Unit). The H-bridge comprises a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4, the first switch tube Q1 and the second switch tube Q2 form a first bridge arm, the third switch tube Q3 and the fourth switch tube Q4 form a second bridge arm, a first node A is arranged between the first switch tube Q1 and the second switch tube Q2, and a second node B is arranged between the third switch tube Q3 and the fourth switch tube Q4.
The control module 100 is configured to obtain a control mode of the DC-DC converter during the last operation when the DC-DC converter operates, and select a control mode of the DC-DC converter during the current operation according to the control mode of the DC-DC converter during the last operation, where the control mode of the DC-DC converter includes a phase shift modulation control mode and a lower tube modulation control mode.
When the control mode of the current operation is selected as the control mode of the phase shift modulation, the control module 100 obtains a total time TA for controlling the H-bridge in a first mode and a total time TB for controlling the H-bridge in a second mode, and determines a relationship between the total time TA and the total time TB to select a mode of controlling the H-bridge, so as to perform temperature equalization control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, wherein when the H-bridge is controlled in the first mode, the first bridge arm is used as an advance bridge arm, and the second bridge arm is used as a lag bridge arm; and when the H bridge is controlled in the second mode, taking the second bridge arm as a leading bridge arm and taking the first bridge arm as a lagging bridge arm. When the control mode during the current work is selected as the control mode of the lower tube modulation, the control module 100 obtains a total time TC for controlling the H bridge in a third mode and a total time TD for controlling the H bridge in a fourth mode, and determines a relationship between the total time TC and the total time TD to select a mode of controlling the H bridge, so as to perform temperature equalization control on the first switching tube, the second switching tube, the third switching tube and the fourth switching tube, wherein when the H bridge is controlled in the third mode, the first switching tube and the third switching tube are used as an upper tube and the second switching tube and the fourth switching tube are used as a lower tube, and the control mode of the lower tube modulation is used to control the first switching tube to the fourth switching tube; and when the H bridge is controlled in the fourth mode, the first switching tube and the third switching tube are used as a lower tube, the second switching tube and the fourth switching tube are used as an upper tube, and the first switching tube to the fourth switching tube are controlled in a control mode of lower tube modulation.
According to an embodiment of the present invention, when the control module selects a manner of controlling the H-bridge according to a relationship between the total time TA and the total time TB, when the total time TA is greater than the total time TB, the control module selects the second manner to control the H-bridge; when the total time TA is less than the total time TB, the control module selects the first mode to control the H bridge; and when the total time TA is equal to the total time TB, the control module selects the first mode or the second mode to control the H bridge.
That is to say, in an embodiment of the present invention, when the DC-DC converter operates in a phase shift modulation control manner, and the control module controls the H-bridge in the first manner a, the time for controlling the H-bridge in the first manner a is recorded, so that the total time TA for controlling the H-bridge in the first manner can be obtained and then stored; and when the control module controls the H bridge in the second mode B, recording the time for controlling the H bridge in the second mode B, so as to obtain the total time TB for controlling the H bridge in the second mode, and then storing the total time TB. Therefore, when the DC-DC converter works in a phase-shift modulation control mode every time, the control module judges the relation between the total time TA and the total time TB, and finally selects a mode for controlling the H bridge according to the relation between the total time TA and the total time TB, so that the temperature balance control of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube is realized.
According to an embodiment of the present invention, when the H-bridge is controlled in the first manner, the control signal output by the control module to the first switching tube is complementary to the control signal output by the second switching tube, and the control signal output by the control module to the third switching tube is complementary to the control signal output by the fourth switching tube, and the first switching tube is turned on with a phase angle ahead of the fourth switching tube, and the second switching tube is turned on with a phase angle ahead of the third switching tube.
When the H-bridge is controlled in the second mode, the control signal output by the control module to the first switching tube is complementary to the control signal output to the second switching tube, and the control signal output to the third switching tube is complementary to the control signal output to the fourth switching tube, and the fourth switching tube is turned on one phase angle ahead of the first switching tube, and the third switching tube is turned on one phase angle ahead of the second switching tube.
According to an embodiment of the present invention, when the control module selects a manner of controlling the H-bridge according to a relationship between the total time TC and the total time TD, the control module selects the fourth manner to control the H-bridge when the total time TC is greater than the total time TD; when the total time TC is smaller than the total time TD, the control module selects the third mode to control the H bridge; and when the total time TC is equal to the total time TD, the control module selects the third mode or the fourth mode to control the H bridge.
That is to say, in an embodiment of the present invention, when the DC-DC converter operates in a down tube modulation control manner, and the control module controls the H-bridge in the third manner C, the time for controlling the H-bridge in the third manner C is recorded, so that the total time TC for controlling the H-bridge in the third manner can be obtained and then stored; when the control module controls the H bridge by adopting the fourth mode D, the time for controlling the H bridge by adopting the fourth mode D is recorded, so that the total time TD for controlling the H bridge by adopting the fourth mode can be obtained and then stored. Therefore, when the DC-DC converter works in a control mode of lower tube modulation each time, the control module judges the relation between the total time TC and the total time TD, and selects a mode of controlling the H bridge according to the relation between the total time TC and the total time TD, so that the temperature balance control of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube can be realized.
According to an embodiment of the present invention, when the H-bridge is controlled in the third manner, the control signal output by the control module to the first switching tube is complementary to the control signal output by the third switching tube and has a fixed duty ratio, and the control module performs PWM control on the falling edges of the control signals output to the second switching tube and the fourth switching tube.
And when the H bridge is controlled in the fourth mode, the control signal output to the second switching tube by the control module is complementary to the control signal output to the fourth switching tube and has a fixed duty ratio, and the control module performs PWM control on the falling edges of the control signals output to the first switching tube and the third switching tube.
In the embodiment of the present invention, as shown in fig. 1, the first switching Transistor Q1, the second switching Transistor Q2, the third switching Transistor Q3 and the fourth switching Transistor Q4 are all IGBTs (Insulated Gate Bipolar transistors), but in another embodiment of the present invention, the first switching Transistor Q1, the second switching Transistor Q2, the third switching Transistor Q3 and the fourth switching Transistor Q4 may be MOS transistors.
According to the DC-DC converter provided by the embodiment of the invention, when the DC-DC converter is started to work, the control mode of the DC-DC converter in the last working is obtained through the control module, and the control mode in the current working is selected according to the control mode of the DC-DC converter in the last working, so that the control mode of phase shift modulation and the control mode of lower tube modulation are alternately carried out in the whole life cycle of the DC-DC converter. When the control mode during the work is selected to be a phase shift modulation control mode, acquiring total time TA for controlling the H bridge in a first mode and total time TB for controlling the H bridge in a second mode through a control module, then judging the relation between the total time TA and the total time TB, and finally selecting a mode for controlling the H bridge according to the relation between the total time TA and the total time TB so as to perform temperature balance control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube; when the control mode of the current work is selected to be the control mode of the lower tube modulation, the total time TC for controlling the H bridge in the third mode and the total time TD for controlling the H bridge in the fourth mode are obtained through the control module, then judging the relation between the total time TC and the total time TD, finally selecting the mode of controlling the H bridge according to the relation between the total time TC and the total time TD, so as to carry out temperature equalization control on the first switching tube, the second switching tube, the third switching tube and the fourth switching tube, therefore, in the whole life cycle, the total time TA and the total time TB when the control mode of phase shift modulation is adopted are equal as much as possible, the total time TC and the total time TD when the control mode of lower tube modulation is adopted are equal as much as possible, so that the heat generation of each switching tube is relatively balanced, under the condition of not increasing the cost, the service life of the switching tube in the H bridge is prolonged, so that the life cycle can be prolonged.
In addition, as shown in fig. 6, an embodiment of the present invention further provides an electric vehicle 10 including the above-described DC-DC converter 20.
The electric automobile provided by the embodiment of the invention can control the DC-DC converter to alternately perform a phase-shift modulation control mode and a lower tube modulation control mode in the whole life cycle, the total time TA and the total time TB when the phase-shift modulation control mode is adopted are equal to the greatest extent, and the total time TC and the total time TD when the lower tube modulation control mode is adopted are equal to the greatest extent, so that the temperature balance control of the first switching tube, the second switching tube, the third switching tube and the fourth switching tube in the H bridge can be realized, the heating of each switching tube is relatively balanced, the working life of the switching tubes in the H bridge is prolonged under the condition of not increasing the cost, and the life cycle of the DC-DC converter is prolonged.
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 (11)

1. A control method of a DC-DC converter is characterized in that the DC-DC converter comprises an H bridge, the H bridge comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the first switch tube and the second switch tube form a first bridge arm, and the third switch tube and the fourth switch tube form a second bridge arm, and the control method comprises the following steps:
when the DC-DC converter works, acquiring a control mode of the DC-DC converter during last working, and selecting the control mode during the current working according to the control mode of the DC-DC converter during the last working, wherein the control mode of the DC-DC converter comprises a phase-shift modulation control mode and a lower tube modulation control mode;
when the control mode of the current work is selected to be the phase shift modulation control mode, acquiring total time TA for controlling the H bridge in a first mode and total time TB for controlling the H bridge in a second mode, and selecting the mode of controlling the H bridge by judging the relation between the total time TA and the total time TB to perform temperature balance control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, wherein when the H bridge is controlled in the first mode, the first bridge arm is used as an advance bridge arm, and the second bridge arm is used as a delay bridge arm; when the H bridge is controlled in the second mode, the second bridge arm is used as an advanced bridge arm, and the first bridge arm is used as a delayed bridge arm;
when the control mode of the current work is selected to be the control mode of the lower tube modulation, acquiring total time TC for controlling the H bridge in a third mode and total time TD for controlling the H bridge in a fourth mode, and selecting the mode of controlling the H bridge by judging the relation between the total time TC and the total time TD so as to perform temperature equalization control on the first switching tube, the second switching tube, the third switching tube and the fourth switching tube, wherein when the H bridge is controlled in the third mode, the first switching tube and the third switching tube are used as upper tubes, the second switching tube and the fourth switching tube are used as lower tubes, and the control mode of the lower tube modulation is adopted to control the first switching tube to the fourth switching tube; when the H bridge is controlled in the fourth mode, the first switching tube and the third switching tube are used as a lower tube and the second switching tube and the fourth switching tube are used as an upper tube, and the first switching tube to the fourth switching tube are controlled in a control mode of lower tube modulation;
and the control mode of the phase-shift modulation and the control mode of the lower tube modulation are alternately carried out.
2. The method according to claim 1, wherein selecting a manner of controlling the H-bridge according to a relationship between the total time TA and the total time TB specifically comprises:
when the total time TA is greater than the total time TB, selecting the second mode to control the H bridge;
when the total time TA is less than the total time TB, selecting the first mode to control the H bridge;
and when the total time TA is equal to the total time TB, selecting the first mode or the second mode to control the H bridge.
3. The control method of a DC-DC converter according to claim 1 or 2, wherein,
when the H bridge is controlled in the first mode, a control signal output to the first switching tube is complementary to a control signal output to the second switching tube, a control signal output to the third switching tube is complementary to a control signal output to the fourth switching tube, the first switching tube is switched on by advancing a phase angle than the fourth switching tube, and the second switching tube is switched on by advancing a phase angle than the third switching tube;
when the H bridge is controlled in the second mode, the control signal output to the first switch tube is complementary to the control signal output to the second switch tube, the control signal output to the third switch tube is complementary to the control signal output to the fourth switch tube, the fourth switch tube is switched on by advancing one phase angle than the first switch tube, and the third switch tube is switched on by advancing one phase angle than the second switch tube.
4. The method according to claim 1, wherein selecting a manner of controlling the H-bridge according to a relationship between the total time TC and the total time TD comprises:
when the total time TC is greater than the total time TD, selecting the fourth mode to control the H bridge;
when the total time TC is smaller than the total time TD, selecting the third mode to control the H bridge;
and when the total time TC is equal to the total time TD, selecting the third mode or the fourth mode to control the H bridge.
5. The control method of a DC-DC converter according to claim 1 or 4, wherein,
when the H bridge is controlled in the third mode, the control signal output to the first switching tube is complementary to the control signal output to the third switching tube and has a fixed duty ratio, and the falling edges of the control signals output to the second switching tube and the fourth switching tube are subjected to PWM control;
when the H bridge is controlled in the fourth mode, the control signal output to the second switching tube is complementary to the control signal output to the fourth switching tube and has a fixed duty ratio, and PWM control is performed on the falling edges of the control signals output to the first switching tube and the third switching tube.
6. A DC-DC converter, comprising:
the bridge comprises an H bridge and a bridge body, wherein the H bridge comprises a first switching tube, a second switching tube, a third switching tube and a fourth switching tube, the first switching tube and the second switching tube form a first bridge arm, and the third switching tube and the fourth switching tube form a second bridge arm;
a control module, configured to obtain a control mode of the DC-DC converter during the last operation when the DC-DC converter operates, and select a control mode of the DC-DC converter during the current operation according to the control mode of the DC-DC converter during the last operation, where the control mode of the DC-DC converter includes a phase-shift modulation control mode and a lower tube modulation control mode, where,
when the control mode of the current work is selected to be the phase shift modulation control mode, the control module obtains total time TA for controlling the H bridge in a first mode and total time TB for controlling the H bridge in a second mode, and selects a mode for controlling the H bridge by judging the relation between the total time TA and the total time TB so as to perform temperature balance control on the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, wherein when the H bridge is controlled in the first mode, the first bridge arm is used as an advance bridge arm, and the second bridge arm is used as a lag bridge arm; when the H bridge is controlled in the second mode, the second bridge arm is used as an advanced bridge arm, and the first bridge arm is used as a delayed bridge arm;
when the control mode of the current work is selected to be the control mode of the lower tube modulation, the control module obtains total time TC for controlling the H bridge in a third mode and total time TD for controlling the H bridge in a fourth mode, and selects the mode of controlling the H bridge by judging the relation between the total time TC and the total time TD so as to perform temperature equalization control on the first switching tube, the second switching tube, the third switching tube and the fourth switching tube, wherein when the H bridge is controlled in the third mode, the first switching tube and the third switching tube are used as upper tubes, the second switching tube and the fourth switching tube are used as lower tubes, and the control mode of the lower tube modulation is adopted to control the first switching tube to the fourth switching tube; when the H bridge is controlled in the fourth mode, the first switching tube and the third switching tube are used as a lower tube and the second switching tube and the fourth switching tube are used as an upper tube, and the first switching tube to the fourth switching tube are controlled in a control mode of lower tube modulation;
and the control mode of the phase-shift modulation and the control mode of the lower tube modulation are alternately carried out.
7. The DC-DC converter of claim 6, wherein the control module selects a manner of controlling the H-bridge based on a relationship between the total time TA and the total time TB, wherein,
when the total time TA is greater than the total time TB, the control module selects the second mode to control the H bridge;
when the total time TA is less than the total time TB, the control module selects the first mode to control the H bridge;
and when the total time TA is equal to the total time TB, the control module selects the first mode or the second mode to control the H bridge.
8. The DC-DC converter according to claim 6 or 7, wherein,
when the H bridge is controlled in the first mode, the control signal output to the first switching tube by the control module is complementary with the control signal output to the second switching tube, and the control signal output to the third switching tube is complementary with the control signal output to the fourth switching tube, and the first switching tube is turned on by a phase angle before the fourth switching tube, and the second switching tube is turned on by a phase angle before the third switching tube;
when the H bridge is controlled in the second mode, the control signal output to the first switch tube by the control module is complementary to the control signal output to the second switch tube, and the control signal output to the third switch tube is complementary to the control signal output to the fourth switch tube, and the fourth switch tube is switched on by advancing the first switch tube by a phase angle, and the third switch tube is switched on by advancing the second switch tube by a phase angle.
9. The DC-DC converter of claim 6, wherein the control module selects a manner of controlling the H-bridge based on a relationship between the total time TC and the total time TD, wherein,
when the total time TC is greater than the total time TD, the control module selects the fourth mode to control the H bridge;
when the total time TC is smaller than the total time TD, the control module selects the third mode to control the H bridge;
and when the total time TC is equal to the total time TD, the control module selects the third mode or the fourth mode to control the H bridge.
10. The DC-DC converter according to claim 6 or 9, wherein,
when the H bridge is controlled in the third mode, the control signal output to the first switching tube by the control module is complementary with the control signal output to the third switching tube and has a fixed duty ratio, and the falling edges of the control signals output to the second switching tube and the fourth switching tube are subjected to PWM control;
when the H bridge is controlled in the fourth mode, the control signal output to the second switching tube by the control module is complementary with the control signal output to the fourth switching tube and has a fixed duty ratio, and PWM control is performed on the falling edges of the control signals output to the first switching tube and the third switching tube.
11. An electric vehicle comprising a DC-DC converter according to any one of claims 6 to 10.
CN201611099657.3A 2016-12-02 2016-12-02 Electric vehicle, DC-DC converter thereof and control method of DC-DC converter Active CN108155795B (en)

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Publication number Priority date Publication date Assignee Title
CN102791072A (en) * 2011-05-20 2012-11-21 东软飞利浦医疗设备系统有限责任公司 High power high voltage generator
CN104600998A (en) * 2015-02-10 2015-05-06 四川英杰电气股份有限公司 Method for controlling uniform heating of switch device of switch power source
US9214865B2 (en) * 2010-04-20 2015-12-15 Rf Micro Devices, Inc. Voltage compatible charge pump buck and buck power supplies

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9214865B2 (en) * 2010-04-20 2015-12-15 Rf Micro Devices, Inc. Voltage compatible charge pump buck and buck power supplies
CN102791072A (en) * 2011-05-20 2012-11-21 东软飞利浦医疗设备系统有限责任公司 High power high voltage generator
CN104600998A (en) * 2015-02-10 2015-05-06 四川英杰电气股份有限公司 Method for controlling uniform heating of switch device of switch power source

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