WO2022165814A1

WO2022165814A1 - Control method and apparatus for power converter, and storage medium

Info

Publication number: WO2022165814A1
Application number: PCT/CN2021/075879
Authority: WO
Inventors: 刘晓红; 刘鹏飞; 宋安国; 石炼之; 吴壬华
Original assignee: 深圳欣锐科技股份有限公司
Priority date: 2021-02-07
Filing date: 2021-02-07
Publication date: 2022-08-11
Also published as: CN113728543A

Abstract

Disclosed in the present application are a control method and apparatus for a power converter, and a storage medium. The method comprises: when the input voltage of a voltage input unit is greater than the output voltage of a voltage output unit, determining a target duty cycle of a second upper bridge arm switching transistor, and according to the target duty cycle, controlling the turn-on duration of a first upper bridge arm switching transistor to adjust the duty cycle of the first upper bridge arm switching transistor, wherein the duty cycle of a first lower bridge arm switching transistor is complementary to the duty cycle of the first upper bridge arm switching transistor, and the duty cycle of a second lower arm switching transistor is complementary to the duty cycle of the second upper bridge arm switching transistor; when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, fixing the duty cycle of the first upper bridge arm switching transistor, and controlling the turn-on duration of the second lower arm switching transistor until the input voltage is less than the output voltage and the output voltage no longer increases. By using the present application, seamless switching of a four-switch DC/DC power converter can be conveniently and efficiently implemented, and switching loss can be reduced.

Description

Control method, device and storage medium for power converter

technical field

The present application relates to the field of power electronic control, and in particular, to a control method, device and storage medium for a power converter.

Background technique

Four-switch DC/DC power converters are widely used in applications that do not require isolation because of their few switching devices and can realize bidirectional flow of energy. Although the four-switch DC/DC power converter has only four switching devices, the control strategy is very complicated. For example, the entire control area can be divided into three modes: BUCK, BUCK-BOOST, and BOOST according to the relationship between the input voltage and the output voltage. However, in this control strategy, there will be a cross section when the three modes are switched, resulting in a decrease in the control performance of the power converter. For another example, the four-switch DC/DC power converter can be regarded as a BUCK bridge arm and a BOOST bridge arm in series, and controlled according to the BUCK-BOOST (buck-boost) mode, and the output voltage can be achieved by adjusting the duty cycle. However, in this control strategy, the switching loss is large and the efficiency is low due to the large-scale switching action of the four switches.

SUMMARY OF THE INVENTION

Based on the above problems, embodiments of the present application provide a control method, device and storage medium for a power converter, which can conveniently and efficiently realize seamless switching of a four-switch DC/DC power converter and reduce switching losses.

A first aspect of an embodiment of the present application provides a control method for a power converter. The power converter includes a step-down unit, a step-up unit, a voltage input unit, and a voltage output unit, and one end of the step-down unit is connected to the voltage input unit. unit, the other end of the step-down unit is connected to the step-up unit through an inductor, the other end of the step-up unit is connected to the voltage output unit, and the step-down unit includes a first upper bridge arm switch tube and a first lower bridge arm connected in series A switch tube, the boosting unit includes a second upper bridge arm switch tube and a second lower bridge arm switch tube connected in series, and the above method includes:

When the input voltage of the voltage input unit is greater than the output voltage of the voltage output unit, determine the target duty cycle of the second upper arm switch tube, and control the first upper arm switch tube according to the target duty cycle The turn-on time is used to adjust the duty cycle of the first upper bridge arm switch tube, wherein the duty cycle of the first lower bridge arm switch tube is complementary to the duty cycle of the first upper bridge arm switch tube, and the second lower arm switch tube is complementary to the duty cycle of the first upper bridge arm switch tube. The duty cycle of the bridge arm switch is complementary to the duty cycle of the second upper bridge arm switch;

When the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the duty cycle of the first upper arm switch is fixed, and the on-time of the second lower arm switch is controlled until the input The voltage is less than the above-mentioned output voltage and the above-mentioned output voltage does not increase any more.

With reference to the first aspect, in a possible implementation manner, the on-time duration of the first high-side switch transistor is controlled according to the target duty cycle to adjust the duty cycle of the first high-side switch transistor, include:

The adjustment range of the duty cycle of the first high-arm switch tube is determined according to the target duty cycle, wherein the adjustment range of the duty cycle of the first high-arm switch tube is greater than 0 and less than or equal to the above-mentioned first The duty cycle of the switch tube of the second upper bridge arm;

According to the adjustment range of the duty ratio of the first upper arm switch tube, the on-time length of the first upper arm switch tube is controlled to adjust the duty ratio of the first upper arm switch tube.

With reference to the first aspect, in a possible implementation manner, the above-mentioned fixing the duty cycle of the first upper bridge arm switch tube includes:

The duty cycle of the first high-arm switch tube is fixed according to the target duty cycle, wherein the duty cycle of the first high-arm switch tube is the same as the target duty cycle.

With reference to the first aspect, in a possible implementation manner, the above-mentioned controlling the on-time duration of the switch tube of the second lower bridge arm includes:

The duty cycle of the second lower arm switch is determined according to the loop output duty cycle and duty cycle coefficient of the power converter, and when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the above The duty cycle factor is the difference between the duty cycle of the first upper bridge arm switch tube and the duty cycle of the first lower bridge arm switch tube, and the loop output duty cycle is equal to the first upper bridge arm switch tube. duty cycle;

The on-time duration of the second lower arm switch tube is controlled according to the duty cycle of the second lower arm switch tube.

With reference to the first aspect, in a possible implementation manner, the duty cycle of the second lower arm switch is smaller than the sum of the target duty cycle and the duty cycle coefficient, and is greater than or equal to the target duty cycle .

In conjunction with the first aspect, in a possible implementation, the above method further includes:

The voltage gain of the output voltage is determined according to the duty cycle of the first high-side switch and the duty cycle of the second high-side switch.

In a second aspect, the present application provides a control device for a power converter, the power converter includes a step-down unit, a step-up unit, a voltage input unit and a voltage output unit, and one end of the step-down unit is connected to the voltage an input unit, the other end of the step-down unit is connected to the step-up unit through an inductor, the other end of the step-up unit is connected to the voltage output unit, and the step-down unit includes a first upper bridge arm switch tube and a first lower bridge connected in series An arm switch tube, the boosting unit includes a second upper bridge arm switch tube and a second lower bridge arm switch tube connected in series, and the device includes:

a first determination module, configured to determine the target duty cycle of the second upper-bridge switch tube when the input voltage of the voltage input unit is greater than the output voltage of the voltage output unit;

a first control module, configured to control the on-time length of the first upper bridge arm switch tube according to the above target duty cycle to adjust the duty cycle of the above first upper bridge arm switch tube, wherein the first lower bridge arm switch tube The duty cycle of the first upper bridge arm switch tube is complementary to that of the first upper bridge arm switch tube, and the duty cycle of the second lower bridge arm switch tube is complementary to the duty cycle of the second upper bridge arm switch tube;

a fixing module, configured to fix the duty cycle of the first upper bridge arm switch tube when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit;

The second control module is configured to control the on-time duration of the second lower arm switch until the input voltage is less than the output voltage and the output voltage does not increase any more.

In combination with the second aspect, in a possible implementation manner, the above-mentioned first control module is also used for:

The adjustment range of the duty cycle of the first high-arm switch tube is determined according to the target duty cycle, wherein the adjustment range of the duty cycle of the first high-arm switch tube is greater than 0 and less than or equal to the second The duty cycle of the switch tube of the upper bridge arm;

The on-time length of the first high-arm switch tube is controlled according to the adjustment range of the duty cycle of the first high-arm switch tube to adjust the duty cycle of the first high-arm switch tube.

In combination with the second aspect, in a possible implementation manner, the above-mentioned fixing module is used for:

In combination with the second aspect, in a possible implementation manner, the above-mentioned second control module is also used for:

With reference to the second aspect, in a possible implementation manner, the duty cycle of the second lower arm switch tube is smaller than the sum of the target duty cycle and the duty cycle coefficient, and is greater than or equal to the target duty cycle .

In combination with the second aspect, in a possible implementation manner, the above-mentioned device further includes:

The second determination module is configured to determine the voltage gain of the output voltage according to the duty cycle of the first upper-bridge switch tube and the duty cycle of the second upper-bridge switch tube.

In a third aspect, the present application provides a computer device, including: a processor, a memory, and a network interface;

The processor is connected to a memory and a network interface, wherein the network interface is used to provide a data communication function, the memory is used to store program codes, and the processor is used to call the program codes to execute the above-mentioned first in this application. Aspects and methods performed by any of the possible implementations of the first aspect.

In a fourth aspect, the present application provides a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and the computer program includes program instructions that, when executed by a processor, execute the above-mentioned first step in the present application. A method performed by an aspect and any possible implementation of the first aspect.

In the present application, when the input voltage of the voltage input unit is greater than the output unit of the voltage output unit, the target duty cycle of the second upper arm switch is determined, and the first upper arm switch is controlled according to the above target duty cycle The on-time length of the transistor is used to adjust the duty cycle of the first upper bridge arm switch transistor. When the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the duty cycle of the switch tube of the first upper bridge arm is fixed, and the duty ratio of the switch tube of the second lower arm arm is determined according to the duty cycle coefficient of the loop output of the power converter. duty cycle, wherein the above duty cycle coefficient is the difference between the duty cycle of the first upper bridge arm switch tube and the duty cycle of the first lower bridge arm switch tube, and the above-mentioned loop output duty cycle is equal to the first the duty cycle of the switch tube of the upper bridge arm, and control the on-time length of the second lower bridge arm according to the duty cycle of the switch tube of the second lower bridge arm, until the input voltage is less than the output voltage and the output voltage No more increase, the function of boosting is realized. This control strategy has only BUCK (buck) mode and BOOST (boost) mode, but no BUCK-BOOST (buck-boost) mode, which reduces switching loss, improves the efficiency of energy transmission, and is simpler and more convenient to realize. Seamless switching of operating modes of a four-switch DC/DC power converter.

Description of drawings

1 is a schematic structural diagram of a four-switch DC/DC power converter provided by the present application;

Fig. 2 is the waveform simulation schematic diagram provided by the application;

3 is a schematic flowchart of a control method of a power converter provided by the present application;

4 is another schematic flowchart of a control method for a power converter provided by the present application;

5 is a schematic structural diagram of a control device for a power converter provided by the present application;

6 is another schematic structural diagram of a control device for a power converter provided by the present application;

FIG. 7 is a schematic structural diagram of a computer device provided by the present application.

Detailed ways

The technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

The control method of the power converter provided by the present application can be applied to a four-switch DC/DC power converter. When the above-mentioned four-switch DC/DC power converter is applied in an electric vehicle, it is mainly used to convert the frequently fluctuating battery pack voltage into A stable voltage provides electric power for the electric vehicle drive system, thereby enhancing the stability of the electric vehicle drive system. This is because the electric motor in the electric vehicle drive system is a typical active load, which can not only absorb the electrical energy of the battery pack and convert it into mechanical energy output, but also convert the mechanical energy into electrical energy and feed it back to the battery pack. However, due to the wide speed range of the electric motor in the electric vehicle, the battery voltage varies greatly during the operation of the electric vehicle. Under such conditions, if the electric motor is directly driven by the battery pack, the driving performance of the electric motor will deteriorate. . The use of the above four-switch DC/DC power converter can stabilize the voltage of the battery pack at a relatively high voltage value within a certain load range, thereby significantly enhancing the stability of the above electric vehicle drive system. The use of the above-mentioned four-switch DC/DC power converter in an electric vehicle can optimize the motor control and improve the overall driving performance of the electric vehicle. On this basis, the embodiment of the present application proposes a control method for a power converter, which is suitable for the above-mentioned four-switch DC/DC power converter, and can maintain the polarity of the DC voltage at both ends of the four-switch DC/DC power converter to be different. Under the changing circumstances, the two-way energy transmission is completed according to the actual needs, which reduces the switching loss, improves the efficiency of energy transmission, and realizes the seamless switching of the working mode of the four-switch DC/DC power converter more simply and conveniently.

Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of a four-switch DC/DC power converter. As shown in FIG. 1, the four-switch DC/DC power converter includes: a step-down unit 1, a step-up unit 2, a voltage For the input unit 3 and the voltage output unit 4, one end of the step-down unit is connected to the voltage input unit, the other end of the step-down unit is connected to the step-up unit through the inductor 04, and the other end of the step-up unit is connected to the voltage output unit. The step-down unit includes a first upper-arm switch 031 and a first lower-arm switch 032 connected in series, and the boost unit includes a second upper-arm switch 034 and a second lower-arm switch 034 connected in series 033. In an optional embodiment of the present application, the above-mentioned four-switch DC/DC power converter can realize bidirectional flow of energy, and there are two operating modes, including a battery discharge mode (that is, a buck (buck) mode) and a battery charging mode ( That is, BOOST (boost mode). Wherein, when the above-mentioned four-switch DC/DC power converter works in the BOOST mode, the above-mentioned voltage input unit may include a first DC power supply 011 and a first filter capacitor 021, and the above-mentioned voltage output unit may include a second DC power supply Power supply 012, second filter capacitor 022; when the above-mentioned four-switch DC/DC power converter works in BUCK (buck) mode, the above-mentioned voltage input unit may include a second DC power supply 012, a second filter capacitor 022, and the above-mentioned voltage output The unit may include a first DC power supply 011 and a first filter capacitor 021 . The above-mentioned first filter capacitor 021 and second filter capacitor 022 are respectively connected in parallel with the output end of the first DC power supply 011 and the output end of the second DC power supply 012 to reduce the AC ripple coefficient and smooth the DC output. In the DC power supply circuit, the filter capacitor not only stabilizes the DC output of the power supply and reduces the influence of the alternating ripple on the circuit, but also absorbs the current fluctuation generated during the operation of the circuit and the interference connected in series through the AC power supply, making the circuit more stable. Work performance is more stable.

Please continue to refer to FIG. 1. As shown in FIG. 1, when the above-mentioned four-switch DC/DC power converter works in the BUCK (buck) mode, the above-mentioned second DC power supply 012 acts as a voltage input unit to the above-mentioned step-down unit and the above-mentioned booster unit. The voltage applied by the voltage unit is greater than the steady-state voltage of the first DC power supply 011 in the voltage output unit. At this time, the current of the inductor 04 flows from the right end of the inductor 04 to the left end of the inductor 04, and the inductor 04 is in an energy storage state. When the four-switch DC/DC power converter operates in the BOOST mode, the voltage applied by the first DC power supply 011 as a voltage input unit to the step-down unit and the boost unit is smaller than the voltage output unit The steady-state voltage of the second DC power supply 012 in the middle, at this time, the current of the inductor 04 flows from the left end of the inductor 04 to the right end of the inductor 04, and the inductor 04 is in a discharging state.

In an optional embodiment of the present application, the first upper arm switch tube 031, the first lower arm switch tube 032 in the above-mentioned step-down unit, and the second upper arm switch tube 034, the first lower arm switch tube 032 in the above-mentioned step-up unit The second lower arm switch tube 033 may be an insulated gate bipolar transistor or a power field effect transistor. Insulated Gate Bipolar Transistor (IGBT) has high operating frequency, low required driving power, low switching loss and fast switching speed, which can make the DC buck-boost circuit quickly realize the conversion between buck and boost. . The power FET has fast switching speed, simple driving circuit and high operating frequency. Wherein, both the first upper bridge arm switch tube 031 in the aforementioned step-down unit and the second lower bridge arm switch tube 033 in the aforementioned step-up unit can be turned on respectively under the action of the pulse width modulation signal applied by the controller and shutdown. Optionally, the above-mentioned controller may be a pulse width modulation (Pulse Width Modulation, PWM) controller (or a pulse width modulator), which modulates the above-mentioned semiconductor power switching device (such as an insulated bipolar transistor according to the change of the corresponding load). ) of the base or gate bias to achieve the change of the on-time and thus the change of the duty cycle. The above-mentioned pulse width modulator is also a very effective controller that uses the digital signal of the microprocessor to control the analog circuit. A series of pulses of equal amplitude are obtained at the terminal, and these pulses are used to replace the sine wave or the desired waveform. That is, multiple pulses are generated in the half cycle of the output waveform, so that the equivalent voltage of each pulse is a sine waveform, and the obtained output waveform is smooth and has few low-order harmonics. By modulating the width of each pulse according to certain rules, the output voltage of the circuit can be changed, and the output frequency can also be changed.

It can be understood that, in an optional embodiment of the present application, the controller uses the pulse width modulation applied to the first high-side switch in the step-down unit and the second low-side switch in the step-up unit. The signal realizes that the above-mentioned switch tubes are turned on and off respectively to control the duty ratio of the above-mentioned first upper bridge arm switch tube and the above-mentioned second lower bridge arm switch tube, so as to realize the above-mentioned four-switch DC/DC power converter from BUCK ( The seamless switching from buck) mode to BOOST (boost) mode changes the flow direction of the inductor current, so that the inductor switches repeatedly between the energy storage state and the energy discharge state, completing the bidirectional transmission of energy, and the output voltage remains at In the steady state, the functions of stabilizing the voltage of the battery pack within a certain range and repeatedly charging the battery pack in the electric vehicle can be realized.

The control method of the power converter provided by the present application will be described below with reference to FIG. 2 . FIG. 2 is a schematic diagram of waveform simulation. As shown in FIG. 2 , the output voltage waveform and the inductor current waveform are sequentially from top to bottom. The above-mentioned output voltage waveform is a fixed value. In practical applications, the above-mentioned output voltage reference value can be set according to different situations, and the input voltage can be controlled by the step-down unit 1 in FIG. 1 and the step-up unit in FIG. 1 above. In 2, the on or off of the switch tubes of each bridge arm reaches the reference value of the output voltage, and the output voltage of the DC power supply is kept constant when the working conditions change. From the above inductor current waveform, it can be seen that the above pulse width modulator controls the above bridges by sending pulse width modulation signals to the buck unit 1 in FIG. The arm switch tube is turned on or off, realizing the function of repeatedly charging and discharging the inductor.

A method for controlling a power converter, a control device for a power converter, and a computer device of the present application will be described below with reference to FIGS. 3 to 7 .

Please refer to FIG. 3 , which is a schematic flowchart of a control method for a power converter provided by the present application. A method for controlling a power converter provided by an embodiment of the present application is applicable to a four-switch DC/DC power converter. For the structure of the above-mentioned four-switch DC/DC power converter, please refer to the schematic structural diagram described in FIG. 1 , here It will not be repeated here. A method for controlling a power converter provided by an embodiment of the present application may include the steps:

S101: Determine the target duty ratio of the second upper bridge arm switch tube.

In some possible implementations, when the input voltage of the voltage input unit is greater than the output voltage of the voltage output unit, the four-switch DC/DC power converter works in BUCK (buck) mode; When the DC/DC power converter operates in the BUCK (buck) mode, the target duty cycle of the second upper bridge arm is determined. The target duty cycle is the upper limit of the duty cycle of the first upper bridge arm switch tube adjusted by the subsequent pulse width modulator.

Specifically, in an optional embodiment of the present application, when the above-mentioned four-switch DC/DC power converter operates in the BUCK (buck) mode, the target of the second high-arm switch tube in the above-mentioned boost unit can be changed to The duty cycle is set to a certain threshold (such as 0.99), and 0.99 is set as the subsequent pulse width modulator to control the conduction time of the first upper bridge arm switch in the above-mentioned step-down unit to adjust the above-mentioned first upper bridge arm The upper limit of the duty cycle of the switch tube.

S102 , controlling the on-time duration of the first upper bridge arm according to the above target duty ratio to adjust the duty ratio of the above first upper bridge arm.

In some possible implementations, when the input voltage of the voltage input unit is greater than the output voltage of the voltage output unit, the four-switch power converter works in a buck (buck) mode, and the controller takes a duty cycle according to the target The ratio determines the adjustment range of the duty cycle of the first upper bridge arm switch tube. Wherein, the adjustment range of the duty cycle of the first high-arm switch tube is greater than 0 and less than or equal to the target duty cycle of the second high-arm switch tube. Within the adjustment range of the duty cycle of the first upper arm switch tube, the on-time duration of the first upper arm switch tube is controlled to adjust the duty cycle of the first upper arm switch tube.

Specifically, in an optional embodiment of the present application, when the above-mentioned four-switch DC/DC power converter operates in a buck (buck) mode, the pulse width modulator converts the above-mentioned first upper bridge arm according to the above-mentioned target duty cycle The duty cycle range of the switch tube is determined to be greater than 0 and less than or equal to 0.99. Optionally, the pulse width modulator sends a pulse width modulation signal to the first upper bridge arm switch tube to control the on-time length of the first upper bridge arm switch tube to adjust the duty cycle of the first upper bridge arm switch tube. The ratio increases from 0 to 0.99. When the pulse width modulator controls the duty cycle of the first high-arm switch to reach 0.99, the input voltage of the voltage input unit in the four-switch DC/DC power converter is equal to the output voltage of the voltage output unit. The wide modulator stops the control of the above-mentioned first upper bridge arm switch tube, the BUCK (buck) mode ends, and the above-mentioned four-switch DC/DC power converter also realizes the conversion of the working mode to the BOOST (boost) mode. .

S103, the duty ratio of the first upper bridge arm switch tube is fixed.

In some feasible implementation manners, when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the controller fixes the duty cycle of the first upper bridge arm switch tube according to the second upper bridge The duty cycle of the duty cycle adjustment of the arm switch tube. At this time, the BUCK (buck) mode ends, and the above-mentioned four-switch DC/DC power converter enters the BOOST (boost) mode.

Specifically, in an optional embodiment of the present application, when the above-mentioned four-switch DC/DC power converter operates in the BUCK (buck) mode, the above-mentioned pulse width modulator controls the conduction of the above-mentioned first high-arm switch tube The duration is adjusted to adjust the duty cycle of the first upper bridge arm switch tube to 0.99. And when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the duty cycle of the first upper bridge arm switch tube is fixed at 0.99, and the control of the first upper bridge arm switch tube is stopped, At this point, the BUCK (buck) mode ends.

S104: Control the on-time duration of the second lower arm switch until the input voltage is less than the output voltage and the output voltage does not increase any more.

In some possible implementations, when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the four-switch DC/DC power converter enters a BOOST (boost) mode. The duty cycle of the loop output of the /DC power converter and the duty cycle coefficient determine the duty cycle of the second lower arm switch tube. Wherein, when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the duty cycle factor is the duty cycle of the first upper arm switch tube and the duty ratio of the first lower arm switch tube The difference value of the above-mentioned loop output duty ratio is equal to the duty ratio of the above-mentioned first upper bridge arm switch tube, and the conduction of the above-mentioned second lower bridge arm switch tube is controlled according to the above-mentioned duty ratio of the above-mentioned second lower bridge arm switch tube until the input voltage is smaller than the output voltage and the output voltage does not increase any more. When the four-switch power DC/DC converter works in the BOOST mode, the controller controls the duty cycle adjustment range of the second lower arm switch tube to be smaller than the target duty cycle and the duty cycle factor The sum is greater than or equal to the above target duty cycle.

Specifically, in an optional embodiment of the present application, when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the four-switch DC/DC power converter enters the BOOST mode, and at this time The pulse width modulator starts to adjust the duty ratio of the switch tube of the second lower bridge arm. The duty cycle of the second lower arm switch tube is determined by the loop output duty cycle and the duty cycle coefficient. The duty cycle of the loop output here is 0.99 when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit. The above duty cycle factor is the difference between the duty cycle of the first upper arm switch tube and the duty cycle of the first lower arm switch tube when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit . Wherein, the duty cycle of the first upper bridge arm switch tube and the duty cycle of the first lower bridge arm switch tube are complementary. Therefore, when the duty cycle of the first upper bridge arm switch tube is 0.99, the above The duty ratio of the switch tube of the first lower arm is 0.01. It can be understood that the duty ratio here is 0.98. In an optional embodiment of the present application, when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the duty cycle of the switch tube of the second lower arm is the same as that of the four-switch DC/DC power converter. The difference between the loop output of 0.99 and the above duty cycle factor of 0.98 is 0.01. The pulse width modulator sends a pulse width modulation signal to the second lower arm switch tube according to the duty ratio of the second lower arm switch tube to control the on-time length of the second lower arm switch tube until the above The input voltage is smaller than the above-mentioned output voltage and the above-mentioned output voltage does not increase any more. When the pulse width modulator controls the duty cycle of the second lower arm switch tube to gradually increase from 0.01, and the on-time duration of the second lower arm switch tube gradually increases, the output voltage of the voltage output unit also gradually increases. Increase. The four-switch DC/DC power converter enters the BOOST (boost) mode, until the pulse width modulator reaches the upper limit of the adjustment range when operating in the BOOST (boost) mode, the pulse width modulator stops the second lower bridge arm. The control of the switch tube, at this time, the output voltage of the above-mentioned voltage output unit reaches the maximum value and does not increase any more. In an optional embodiment of the present application, when the pulse width modulator operates in a BOOST (boost) mode, the duty cycle adjustment range of the second lower arm switch tube is greater than or equal to 0.99 and less than 1.97.

In the present application, when the input voltage of the voltage input unit is greater than the output unit of the voltage output unit, the target duty cycle of the second upper arm switch is determined, and the first upper arm switch is controlled according to the above target duty cycle The on-time length of the transistor is used to adjust the duty cycle of the first upper bridge arm switch transistor. When the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the duty cycle of the switch tube of the first upper bridge arm is fixed, and the duty ratio of the switch tube of the second lower arm arm is determined according to the duty cycle coefficient of the loop output of the power converter. duty cycle, wherein the above duty cycle factor is the difference between the duty cycle of the first upper bridge arm switch tube and the duty cycle of the first lower bridge arm switch tube, and the above loop output duty cycle is equal to the first upper bridge arm The duty cycle of the switch tube of the arm switch, and control the on-time of the second lower arm according to the duty cycle of the switch tube of the second lower arm, until the input voltage is less than the output voltage and the output voltage is no longer Increase, to achieve the function of boost. This control strategy only has BUCK (buck) mode and BOOST (boost) mode, and there is no BUCK-BOOST (buck-boost) mode. The tube sends the pulse width modulation signal to quickly realize the seamless switching of the working mode of the four-switch DC/DC converter, which is simple to implement, reduces the switching loss and improves the efficiency of energy transmission.

Please refer to FIG. 4 , which is another schematic flowchart of a control method for a power converter provided by the present application. The method may be performed by a computer device. The method shown in Figure 4 may include the following steps:

S201 , determining the target duty cycle of the second upper bridge arm switch tube.

The specific implementation of this step S201 may refer to the description of step S101 in the embodiment corresponding to FIG. 3 above, which will not be repeated here.

S202 , controlling the on-time duration of the first upper bridge arm according to the above target duty ratio to adjust the duty ratio of the above first upper bridge arm.

The specific implementation of this step S202 may refer to the description of step S102 in the embodiment corresponding to FIG. 3 above, which will not be repeated here.

S203, the duty ratio of the first upper bridge arm switch tube is fixed.

The specific implementation of this step S203 may refer to the description of step S103 in the embodiment corresponding to FIG. 3 above, which will not be repeated here.

S204 , controlling the on-time duration of the second lower arm switch tube until the input voltage is less than the output voltage and the output voltage does not increase any more.

For the specific implementation of this step S204, reference may be made to the description of step S104 in the embodiment corresponding to FIG. 3 above, which will not be repeated here.

S205: Determine the voltage gain of the output voltage according to the duty cycle of the first high-arm switch tube and the duty cycle of the second high-arm switch tube.

It can be understood that the voltage gain of the output voltage is the voltage of the output voltage unit divided by the voltage of the input voltage unit, and the first bridge arm voltage is the duty cycle of the first upper bridge arm switch tube multiplied by the voltage of the input voltage unit; The voltage of the second bridge arm is the duty cycle of the second upper bridge arm switch tube multiplied by the voltage of the output voltage unit. To sum up, the voltage gain of the above-mentioned output voltage is the duty ratio of the above-mentioned first high-arm switch tube divided by the above-mentioned duty ratio of the above-mentioned second high-arm switch tube. Therefore, when the voltage of the above-mentioned input voltage unit is greater than the voltage of the above-mentioned output voltage unit, the duty cycle of the first high-side switch tube and the duty cycle of the second high-side switch tube are adjusted to make the output voltage The voltage gain is less than 1 and greater than 0; when the voltage of the input voltage unit is equal to the voltage of the output voltage unit, adjust the duty cycle of the first upper bridge arm switch tube and the duty cycle of the second upper bridge arm switch tube In order to make the voltage gain of the output voltage equal to 1; when the voltage of the input voltage unit is less than the voltage of the output voltage unit, adjust the duty cycle of the first upper bridge arm switch tube and the second upper bridge arm switch tube. duty cycle so that the voltage gain of the output voltage is greater than one.

Further, please refer to FIG. 5 , which is a schematic structural diagram of a control device for a power converter provided by the present application. The control device of the power converter can be a computer program (including program code) running in the computer equipment, for example, the control device of the power converter is an application software; the control device of the power converter can be used to execute the present invention. The corresponding steps in the method provided by the application. As shown in FIG. 5 , the power converter includes: a step-down unit, a step-up unit, a voltage input unit and a voltage output unit, one end of the step-down unit is connected to the voltage input unit, and the other end of the step-down unit is connected through an inductor The boosting unit, the other end of the boosting unit is connected to the voltage output unit, the step-down unit includes a first upper bridge arm switch tube and a first lower bridge arm switch tube connected in series, and the boost unit includes a second bridge arm switch tube connected in series. For the upper bridge arm switch tube and the second lower bridge arm switch tube, the above control device includes: a first determination module 10 , a first control module 20 , a fixing module 30 , and a second control module 40 .

a first determination module 10, configured to determine the target duty cycle of the second upper-bridge switch tube when the input voltage of the voltage input unit is greater than the output voltage of the voltage output unit;

The first control module 20 is configured to control the on-time length of the first high-arm switch tube according to the target duty cycle determined by the first determination module 10 to adjust the duty cycle of the first high-arm switch tube, wherein The duty ratio of the first lower arm switch is complementary to the duty ratio of the first upper arm switch, and the duty ratio of the second lower arm switch is the same as the duty ratio of the second upper arm switch. Complementary empty ratio;

The fixing module 30 is configured to fix the duty cycle of the first upper bridge arm switch tube when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit;

The second control module 40 is configured to control the conduction duration of the second lower arm switch until the input voltage is less than the output voltage and the output voltage does not increase any more.

In a possible implementation manner, the above-mentioned first control module 10 is further configured to:

In a possible implementation manner, the above-mentioned fixing module 30 is used for:

In a possible implementation manner, the above-mentioned second control module 40 is further configured to:

In a possible implementation manner, the duty cycle of the second lower arm switch tube is smaller than the sum of the target duty cycle and the duty cycle coefficient, and is greater than or equal to the target duty cycle.

In a possible implementation, please refer to FIG. 6 together, the above-mentioned device further includes:

The second determination module 50 is configured to determine the voltage gain of the output voltage according to the duty cycle of the first high-arm switch and the duty cycle of the second high-arm switch.

The specific implementation manner of the first determination module 10 , the first control module 20 , the fixing module 30 , the second control module 40 and the second determination module 50 can be referred to the steps S101 to S104 in the embodiment corresponding to FIG. 3 above. , and/or the description of step S201 to step S205 in the above-mentioned embodiment corresponding to FIG. 4 , which will not be repeated here. In addition, the description of the beneficial effects of using the same method will not be repeated.

Further, please refer to FIG. 7 , which is a schematic structural diagram of the computer device provided by the present application. As shown in FIG. 7 , the computer device 1000 may include: at least one processor 1001 , such as a CPU, at least one network interface 1003 , memory 1004 , and at least one communication bus 1002 . Among them, the communication bus 1002 is used to realize the connection and communication between these components. The network interface 1003 may optionally include a standard wired interface and a wireless interface (eg, a WI-FI interface). The memory 1004 may be a high-speed random access memory (RAM) memory, or may be a non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 1004 can optionally also be at least one storage device located remotely from the aforementioned processor 1001 . As shown in FIG. 6, the memory 1004, which is a computer storage medium, may include an operating system, a network communication module, and a device control application program.

In the computer device 1000 shown in FIG. 7, the processor 1001 can be used to call the device control application program stored in the memory 1004 to realize:

In a possible implementation manner, the above-mentioned controlling the on-time duration of the first upper bridge arm switch tube according to the target duty ratio to adjust the duty ratio of the aforementioned first upper bridge arm switch tube includes:

In a possible implementation manner, the above-mentioned fixing the duty cycle of the switch tube of the first upper bridge arm includes:

In a possible implementation manner, the above-mentioned controlling the on-time duration of the switch tube of the second lower bridge arm includes:

In a possible implementation, the above method further includes:

In addition, it should be pointed out here that: the present application also provides a computer-readable storage medium, and the computer-readable storage medium stores a computer program executed by a control device of the aforementioned power converter, and The computer program includes program instructions, and when the processor executes the program instructions, it can execute the description of the control method for a power converter in the embodiment corresponding to FIG. 3 and/or FIG. 4 . Let's go into details. In addition, the description of the beneficial effects of using the same method will not be repeated. For technical details not disclosed in the computer-readable storage medium embodiments involved in the present application, please refer to the description of the method embodiments of the present application. By way of example, program instructions may be deployed to be executed on one computing device, or on multiple computing devices located at one site.

Those of ordinary skill in the art can understand that all or part of the process in the method of the above embodiment can be implemented by instructing the relevant hardware through a computer program, and the above program can be stored in a computer-readable storage medium, and the program is in During execution, it may include the processes of the embodiments of the above-mentioned methods. The computer-readable storage medium may be a control device of a power converter provided in any of the foregoing embodiments or an internal storage unit of the above-mentioned device, such as a hard disk or a memory of an electronic device. The computer-readable storage medium can also be an external storage device of the electronic device, such as a pluggable hard disk, a smart media card (SMC), a secure digital (SD) card equipped on the electronic device, Flash card (flash card), etc. The above-mentioned computer-readable storage medium may also include a magnetic disk, an optical disk, a read-only memory (read-only memory, ROM) or a random access memory, and the like. Further, the computer-readable storage medium may also include both an internal storage unit of the electronic device and an external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by the electronic device. The computer-readable storage medium can also be used to temporarily store data that has been or will be output.

The terms "first", "second" and the like in the claims, description and drawings of the present invention are used to distinguish different objects, rather than to describe a specific order. Furthermore, the terms "comprising" and "having", and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally also includes For other steps or units inherent to these processes, methods, products or devices. Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification is not necessarily all referring to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments. As used in this specification and the appended claims, the term "and/or" refers to and including any and all possible combinations of one or more of the associated listed items.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. Interchangeability, the above description has generally described the components and steps of each example in terms of function. Skilled artisans may use different methods of implementing the described functionality for each particular application, but such implementations should not be considered beyond the scope of the present invention.

In the embodiments provided in this application, the disclosed circuits and methods may also be implemented in other manners. For example, the device embodiments described above are illustrative. For example, the division of circuit modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated. to another system, or some features can be ignored, or not implemented.

Each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

A control method for a power converter, the power converter includes a step-down unit, a step-up unit, a voltage input unit and a voltage output unit, one end of the step-down unit is connected to the voltage input unit, and the step-down unit is connected to the voltage input unit. The other end of the voltage unit is connected to the boost unit through an inductor, the other end of the boost unit is connected to the voltage output unit, and the step-down unit includes a first upper bridge arm switch tube and a first lower bridge arm connected in series A switch tube, the boosting unit includes a second upper bridge arm switch tube and a second lower bridge arm switch tube connected in series, wherein the method includes:

When the input voltage of the voltage input unit is greater than the output voltage of the voltage output unit, determine the target duty cycle of the second high-side switch, and control the first high-end switch according to the target duty cycle The on-time length of the bridge arm switch tube is used to adjust the duty cycle of the first upper bridge arm switch tube, wherein the duty cycle of the first lower bridge arm switch tube and the duty cycle of the first upper bridge arm switch tube Complementary duty cycle, the duty cycle of the second lower bridge arm switch tube is complementary to the duty cycle of the second upper bridge arm switch tube;

When the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit, the duty cycle of the first upper arm switch is fixed, and the on-time of the second lower arm switch is controlled , until the input voltage is less than the output voltage and the output voltage no longer increases.
The method according to claim 1, wherein the on-time duration of the first high-side switch transistor is controlled according to the target duty cycle to adjust the duty of the first high-side switch transistor than, including:

The adjustment range of the duty cycle of the first upper arm switch is determined according to the target duty cycle, wherein the adjustment range of the duty cycle of the first upper arm switch is greater than 0 and less than or equal to the duty cycle of the second upper bridge arm switch tube;

The on-time length of the first high-arm switch tube is controlled according to the adjustment range of the duty cycle of the first high-arm switch tube to adjust the duty cycle of the first high-arm switch tube.
The method according to claim 1, wherein the fixing the duty cycle of the first upper bridge arm switch tube comprises:

The duty cycle of the first high-arm switch tube is fixed according to the target duty cycle, wherein the duty cycle of the first high-arm switch tube is the same as the target duty cycle.
The method according to claim 1 or 3, wherein the controlling the on-time duration of the switch tube of the second lower bridge arm comprises:

The duty cycle of the second lower arm switch is determined according to the loop output duty cycle and the duty cycle coefficient of the power converter, wherein the input voltage of the voltage input unit is equal to the output of the voltage output unit voltage, the duty cycle factor is the difference between the duty cycle of the first upper arm switch and the duty cycle of the first lower arm switch, and the loop output duty cycle is equal to the duty cycle of the first upper bridge arm switch tube;

The on-time duration of the second lower arm switch tube is controlled according to the duty cycle of the second lower arm switch tube.
The method according to claim 4, wherein the duty cycle of the second lower arm switch is less than the sum of the target duty cycle and the duty cycle coefficient, and is greater than or equal to the target duty cycle.
The method according to claim 2 or 5, wherein the method further comprises:

The voltage gain of the output voltage is determined according to the duty cycle of the first high-side switch and the duty cycle of the second high-side switch.
A control device for a power converter, characterized in that the power converter includes: a step-down unit, a step-up unit, a voltage input unit and a voltage output unit, and one end of the step-down unit is connected to the voltage input unit , the other end of the step-down unit is connected to the step-up unit through an inductance, the other end of the step-up unit is connected to the voltage output unit, and the step-down unit includes a series-connected first high-arm switch tube and a second A lower bridge arm switch tube, the boosting unit includes a second upper bridge arm switch tube and a second lower bridge arm switch tube connected in series, and the device includes:

a first determining module, configured to determine a target duty cycle of the second upper-bridge switch tube when the input voltage of the voltage input unit is greater than the output voltage of the voltage output unit;

A first control module, configured to control the on-time length of the first upper bridge arm switch tube according to the target duty cycle to adjust the duty cycle of the first upper bridge arm switch tube, wherein the first lower arm switch tube is The duty cycle of the bridge arm switch tube is complementary to the duty cycle of the first upper bridge arm switch tube, and the duty cycle of the second lower bridge arm switch tube is the same as the duty cycle of the second upper bridge arm switch tube than complementary;

a fixing module, configured to fix the duty cycle of the first upper bridge arm switch tube when the input voltage of the voltage input unit is equal to the output voltage of the voltage output unit;

The second control module is configured to control the on-time duration of the second lower arm switch until the input voltage is less than the output voltage and the output voltage does not increase any more.
The device according to claim 7, wherein the first control module is used for:

The adjustment range of the duty cycle of the first upper arm switch is determined according to the target duty cycle, wherein the adjustment range of the duty cycle of the first upper arm switch is greater than 0 and less than or equal to the duty cycle of the switch tube of the second upper bridge arm;

The on-time length of the first high-arm switch tube is controlled according to the adjustment range of the duty cycle of the first high-arm switch tube to adjust the duty cycle of the first high-arm switch tube.
A computer device, characterized in that it includes: a processor, a memory, and a network interface;

The processor is connected to a memory and a network interface, wherein the network interface is used to provide a data communication function, the memory is used to store program codes, and the processor is used to call the program codes to execute any one of claims 1-6 method described in item.
A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, the computer program includes program instructions, and when the program instructions are executed by a processor, any one of claims 1-6 is executed. method described in item.