WO2021254534A2 - 同步buck电路的控制方法、装置、系统和电子装置 - Google Patents

同步buck电路的控制方法、装置、系统和电子装置 Download PDF

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Publication number
WO2021254534A2
WO2021254534A2 PCT/CN2021/110805 CN2021110805W WO2021254534A2 WO 2021254534 A2 WO2021254534 A2 WO 2021254534A2 CN 2021110805 W CN2021110805 W CN 2021110805W WO 2021254534 A2 WO2021254534 A2 WO 2021254534A2
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Prior art keywords
duty cycle
synchronous
buck circuit
synchronous buck
current
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PCT/CN2021/110805
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English (en)
French (fr)
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WO2021254534A3 (zh
Inventor
王雷
陈熙
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深圳市正浩创新科技股份有限公司
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Priority to JP2021562301A priority Critical patent/JP7106769B2/ja
Priority to KR1020217036453A priority patent/KR102572644B1/ko
Priority to EP21825519.8A priority patent/EP4307547A2/en
Publication of WO2021254534A2 publication Critical patent/WO2021254534A2/zh
Publication of WO2021254534A3 publication Critical patent/WO2021254534A3/zh
Priority to US17/949,838 priority patent/US20230011390A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1588—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load comprising at least one synchronous rectifier element
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0009—Devices or circuits for detecting current in a converter
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0032—Control circuits allowing low power mode operation, e.g. in standby mode
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

  • This application relates to the technical field of circuit control, and in particular to a method, device, system and electronic device for controlling a synchronous BUCK circuit.
  • BUCK circuit is a kind of step-down circuit, which adopts DC-DC circuit structure to realize the step-down conversion from DC to DC.
  • BUCK circuits are widely used in various circuits.
  • When large current is output synchronous tubes are often used for freewheeling in order to improve efficiency.
  • the switch tube will not work and use the diode for freewheeling, and when the current is small and the load is light, the BUCK circuit often works in the intermittent working mode.
  • the synchronous tube is switched in different working states, there is also a sudden switch between discontinuous mode and continuous mode. Due to the large difference in output/input gain of the BUCK circuit in the two modes, the BUCK circuit will generate a larger inrush current. , The output of the circuit will also appear transient overshoot or fall.
  • a method, device, system, and electronic device for controlling a synchronous BUCK circuit are provided.
  • the embodiment of the present application provides a method for controlling a synchronous BUCK circuit, including:
  • a corresponding drive signal is generated according to the duty cycle to control the synchronous BUCK circuit.
  • the embodiment of the present application provides a method for controlling a synchronous BUCK circuit, including:
  • the first duty cycle formula is:
  • D is the duty cycle of the main switch
  • V in is the currently sampled input voltage
  • V out is the currently sampled output voltage
  • L is the inductance of the inductor in the synchronous BUCK circuit
  • I x is all The turn-off current threshold
  • T s is the switching period of the main switch tube.
  • An embodiment of the present application also provides a control device for a synchronous BUCK circuit, including:
  • the acquisition module is used to acquire the sampled input voltage, output voltage, and output current of the synchronous BUCK circuit, and to acquire the current state of the synchronous switch in the synchronous BUCK circuit, and is also used to In the on state, obtain the shutdown current threshold;
  • a switching module configured to switch the synchronous switch tube to the off state when the output current is less than the turn-off current threshold
  • a calculation module configured to calculate the duty cycle of the main switch in the synchronous BUCK circuit according to the input voltage, the output voltage, and the turn-off current threshold;
  • the drive control module is used to generate a corresponding drive signal according to the duty cycle to control the synchronous BUCK circuit.
  • the embodiment of the present application provides a synchronous BUCK circuit system, including: a synchronous BUCK circuit and a control device, wherein the control device is used to execute a control method of the synchronous BUCK circuit;
  • the synchronous BUCK circuit includes a main switch tube, an inductor, Synchronous switch tube, energy storage capacitor and sampling circuit;
  • the sampling circuit is used to collect the input voltage, output voltage and output current of the synchronous BUCK circuit, and output to the control device;
  • the first end of the main switch tube is used to connect to the positive pole of the power supply, the second end is connected to the first end of the inductor, and the control end is used to connect to the control device;
  • the first end of the synchronous switch tube is respectively connected to the second end of the main switch tube and the first end of the inductor, the second end is used to connect to the negative electrode of the power supply, and the control end is used to connect to the control device ;
  • the second end of the inductor is connected to the positive electrode of the energy storage capacitor, the negative electrode of the energy storage capacitor is used to connect to the negative electrode of the power supply, and both ends of the energy storage capacitor are also used for parallel loads;
  • the control method of the synchronous BUCK circuit includes:
  • a corresponding drive signal is generated according to the duty cycle to control the synchronous BUCK circuit.
  • An embodiment of the present application provides an electronic device, and the electronic device includes the synchronous BUCK circuit system as described in the foregoing embodiment.
  • Fig. 1 shows a schematic structural diagram of a synchronous BUCK circuit in an embodiment of the present application.
  • Fig. 2 shows the first flow diagram of the control method of the synchronous BUCK circuit.
  • Fig. 3 shows a schematic structural diagram of a loop compensation module containing a synchronous BUCK circuit of the embodiment.
  • FIG. 4 shows a schematic diagram of a second flow of a method for controlling a synchronous BUCK circuit according to an embodiment of the present application.
  • FIG. 5 shows a schematic diagram of a third flow of a method for controlling a synchronous BUCK circuit according to an embodiment of the present application.
  • Fig. 6 shows a schematic structural diagram of a control device for a synchronous BUCK circuit in an embodiment of the present application.
  • this embodiment proposes a method for controlling a synchronous BUCK circuit, which can reduce the dynamic impact generated when the switch tube in the circuit is turned on/off, thereby improving the performance of the circuit.
  • the synchronous BUCK circuit 100 includes a main switching tube Q1, an inductor L, a synchronous switching tube Q2, and an energy storage capacitor C, wherein the first end of the main switching tube Q1 is used to connect to the power supply BAT Positive, the second end is connected to the first end of the inductor L, and the control end is used to connect to the control device; the first end of the synchronous switch Q2 is connected to the second end of the main switch Q1 and the first end of the inductor L, and the second end It is used to connect the negative pole of the power supply, and the control terminal is used to connect to the control device; the second end of the inductor L is connected to the positive pole of the energy storage capacitor C, and the negative pole of the energy storage capacitor C is used to connect to the negative pole of the power supply BAT. Both ends of the storage capacitor C is also used to parallel load R L, R L the load that provide energy and the like.
  • both the main switching tube Q1 and the synchronous switching tube Q2 can be implemented by MOS tubes. It can be understood that the synchronous switch tube Q2 in the above synchronous BUCK circuit uses a rectifier MOS tube with low on-resistance to replace the freewheeling diode in the general BUCK circuit to reduce the rectification loss in the circuit, which can greatly improve the conversion efficiency of the circuit.
  • the body diode in the synchronous switch tube Q2 shown in FIG. 1 can be used to realize the continuous current function of the synchronous BUCK circuit in the discontinuous mode.
  • the aforementioned synchronous switch tube Q2 has a parasitic diode (ie, a body diode).
  • the body diode in the synchronous switch tube Q2 can also be replaced by an external independent diode.
  • this embodiment combines the output current and the state of the synchronous switch Q2 to predict the duty cycle of the main switch Q1 at different times, so as to perform predictive control on the main switch Q1 and the synchronous switch Q2 according to the predicted value. Control to reduce the dynamic impact generated in the circuit.
  • the control method of the synchronous BUCK circuit will be described in detail below. It can be understood that the synchronous BUCK circuit in FIG. 1 is a basic circuit, and the control method in this embodiment can also be applied to other modified synchronous BUCK circuits.
  • Step S110 Obtain the input voltage, output voltage and output current of the synchronous BUCK circuit 100.
  • a corresponding sampling circuit can be arranged at a corresponding position, for example, a sampling unit can be arranged at the input end of the synchronous BUCK circuit 100 for sampling the connected power supply voltage V in .
  • the sampling unit can be It is composed of voltage divider resistors and analog-to-digital converter (ADC). Sampling the output current Iout and the output voltage V out, the sampling unit may be provided at the output of the other circuit, e.g., a current transformer or the like can be output current sampling. It can be understood that the specific structure of the sampling circuit here can be selected according to actual requirements and is not limited here.
  • Step S120 Obtain the current state of the synchronous switch Q2.
  • Step S130 when the synchronous switch Q2 is in the on state, obtain the turn-off current threshold.
  • this embodiment sets two current thresholds, namely the turn-off current threshold and the turn-on current threshold.
  • the turn-off current threshold is less than the turn-on current threshold, and the turn-on current threshold and the turn-off current threshold respectively determine the turn-on time and the turn-off time of the synchronous switch Q2.
  • the turn-off current threshold value is obtained, which is used to determine whether the synchronous switch tube Q2 needs to be turned off currently in combination with the output current. For example, if the current output current is less than the turn-off current threshold, the synchronous switch Q2 is controlled to switch from the current on state to the off state, that is, step S140, otherwise the current on state is maintained.
  • Step S140 when the output current is less than the turn-off current threshold, switch the synchronous switch Q2 to the off state.
  • Step S150 Calculate the duty cycle of the main switch Q1 according to the input voltage, the output voltage, and the turn-off current threshold.
  • the duty cycle of the main switch Q1 at this time can be calculated according to the following first duty cycle formula.
  • the first duty cycle formula is:
  • D is the duty cycle of the main switch
  • V in is the currently sampled input voltage
  • V out is the currently sampled output voltage
  • L is the inductance of the inductor in the synchronous BUCK circuit
  • I x is the turn-off current threshold
  • T s is the switching period of the main switching tube Q1.
  • step S160 a corresponding driving signal is generated according to the duty ratio to control the synchronous BUCK circuit 100.
  • the corresponding PWM drive signal can be generated according to the duty cycle to control the main switching tube Q1 and the synchronous switching tube Q2, because the duty cycle is based on the main switching tube Q1. If the working mode is predicted, the predicted duty cycle is directly used to control the main switching tube Q1, which can reduce the main switching tube Q1 in the CCM (continuous mode) and DCM (discontinuous mode) switching process. The resulting current impact improves the reliability and output performance of the main switching tube Q1.
  • the synchronous BUCK circuit 100 can be controlled by a variety of control techniques, such as voltage-type control, average current control, or peak current control. In actual engineering, suitable control methods can be selected for different requirements.
  • the synchronous BUCK circuit 100 further includes a loop compensation module, which uses the deviation E between the sampled output voltage V out and the preset reference voltage Vref as the loop compensation module The output voltage U is used to correct the adjustment amount of the deviation according to the need, so as to realize the adjustment of the output voltage.
  • the loop compensation module may also include a current loop structure, the output voltage U is used as a given value of the current loop, and the corresponding duty cycle control signal is generated after control and adjustment according to the given value and the output current. .
  • the loop compensation module is constructed with a corresponding discrete domain difference equation, through which the duty cycle of the main switch Q1 or an intermediate quantity that can be used to solve the duty cycle can be calculated.
  • the expression of the discrete domain difference equation is:
  • U represents the duty cycle or the intermediate value used to calculate the duty cycle
  • n represents the current sample
  • n-1 represents the previous sample
  • E represents the deviation between the output voltage and the reference voltage
  • i and j are both greater than Or an integer equal to 2
  • a 1 , A i , B 1 , B 2 and B j respectively represent the gain coefficients of the corresponding items. It can be understood that if one of the terms does not exist, it indicates that the gain coefficient of the corresponding term is 0, that is, the output of the differential equation is not affected by the term.
  • control method of the synchronous BUCK circuit further includes:
  • step S210 when the synchronous switch Q2 is in the on state and the output current is greater than or equal to the turn-off current threshold, the current state of the synchronous switch Q2 is maintained.
  • the duty cycle of the main switch Q1 can be calculated according to the aforementioned discrete domain difference equation, that is, the traditional duty cycle determination method is used to determine the duty cycle or to determine the intermediate quantity of the occupancy ratio.
  • Step S220 Calculate the duty cycle of the main switch Q1 or the intermediate value of the duty cycle according to the deviation between the output voltage and the reference voltage and the discrete domain differential equation.
  • the duty cycle can be calculated according to actual requirements or used to solve the intermediate value of the duty cycle. For example, taking a PID loop compensation structure of voltage type control mode as an example, the corresponding differential equation is expressed as:
  • U(n) represents the current output intermediate value used to calculate the duty cycle, which is the control voltage
  • U(n-1) represents the previous output, that is, the last historical intermediate value
  • E(n) represents The deviation value between the currently sampled output voltage and the reference voltage
  • E(n-1) and E(n-2) represent the historical deviation values of the previous and the previous two respectively.
  • the output of the corresponding differential equation can directly output the duty cycle of the PWM signal, which will not be described here.
  • the two switch tubes in the synchronous BUCK circuit 100 can be controlled accordingly. It can be understood that for different types of loop controllers, such as PI control, PD control, or PID control, the expressions of the corresponding differential equations are often different.
  • Step S230 Generate a corresponding drive signal according to the duty cycle to control the synchronous BUCK circuit 100, or after obtaining the duty cycle according to the intermediate quantity, use the duty cycle to generate a corresponding drive signal to control the synchronous BUCK circuit 100 for control.
  • the control device can generate a corresponding PWM drive signal according to the duty cycle to drive and control the main switch transistor Q1 and the synchronous switch transistor Q2. If the output in the differential direction is an intermediate quantity, such as the above-mentioned control voltage, etc., the control device can convert it to the duty cycle of the main switch Q1, and then output the corresponding PWM drive signal.
  • the control method of the synchronous BUCK circuit further includes:
  • step S310 when the synchronous switch Q2 is in the off state, the turn-on current threshold is acquired.
  • Step S320 when the output current is greater than the turn-on current threshold, switch the synchronous switch Q2 to the on state.
  • the turn-on current threshold is obtained, which is used to determine whether the synchronous switch tube Q2 needs to be turned on in combination with the magnitude of the output current. For example, if the current output current is greater than the turn-on current threshold, the synchronous switch Q2 is controlled to switch from the current off state to the on state, that is, step S320 is executed, otherwise the current off state is maintained.
  • Step S330 Calculate the duty cycle of the main switch Q1 according to the input voltage and the output voltage.
  • the duty cycle of the main switch Q1 can be calculated according to the following second duty cycle formula .
  • the second duty cycle formula is:
  • D represents the duty cycle of the main switch
  • V in is the current sampled input voltage
  • V out is the current sampled output voltage
  • step S340 a corresponding driving signal is generated according to the duty ratio to control the synchronous BUCK circuit 100.
  • the corresponding PWM drive signal can be generated according to the duty cycle to control the main switching tube Q1 and the synchronous switching tube Q2, because the duty cycle is based on the next of the main switching tube Q1
  • the predicted duty cycle is directly used to control the main switching tube Q1, which can reduce the current impact generated by the main switching tube Q1 during the mode switching process, thereby improving the reliability and reliability of the main switching tube Q1. Output performance.
  • control method of the synchronous BUCK circuit further includes:
  • step S410 when the synchronous switch Q2 is in the off state and the output current is less than or equal to the on-current threshold, the current state of the synchronous switch Q2 is maintained.
  • Step S420 Calculate the duty cycle of the main switch Q1 or the intermediate value of the duty cycle according to the deviation between the output voltage and the reference voltage and the discrete domain differential equation.
  • the synchronous switch Q2 is in the off state, and the output current at this time is less than or equal to the turn-on current threshold, it indicates that the timing of turning on the synchronous switch Q2 has not yet been reached, so it will maintain In its current off state, until the output current is greater than the turn-on current threshold, the synchronous switch Q2 is controlled to be turned on.
  • Step S430 Generate a corresponding drive signal according to the duty cycle to control the synchronous BUCK circuit 100; or, after obtaining the duty cycle according to the intermediate quantity, use the duty cycle to generate a corresponding drive signal to control the synchronous BUCK circuit.
  • the circuit 100 performs control.
  • step S230 the duty cycle is used to control the synchronous BUCK circuit 100.
  • the method further includes:
  • the duty cycle when the duty cycle is calculated using the above-mentioned first duty cycle formula or the second duty cycle formula, since the duty cycle at this time is directly calculated by the formula, the duty cycle will also be calculated according to the duty cycle.
  • the comparison adjustment assigns values to the adjustable variables of the discrete domain difference equation, such as historical output values U(n-1),..., U(ni), etc.
  • the synchronous BUCK circuit control method of this embodiment divides the control of the switch tube into multiple branches. , And use the corresponding duty cycle calculation formula to give the predictive control value of the duty cycle at different times, which can avoid large dynamic impacts, thereby affecting the reliability and output performance of the switch tube.
  • the synchronous BUCK circuit 100 includes a main switching tube Q1, an inductor L, a synchronous switching tube Q2, and an energy storage capacitor C, wherein the first end of the main switching tube Q1 is used to connect the positive electrode of the power supply BAT , The second end is connected to the first end of the inductor L, and the control end is used to connect to the control device 200; the first end of the synchronous switch Q2 is connected to the second end of the main switch Q1 and the first end of the inductor L, and the second end Used to connect the negative electrode of the power supply BAT, the control terminal is used to connect to the control device 200; the second end of the inductor L is connected to the positive electrode of the energy storage capacitor C, and the negative electrode of the energy storage capacitor C is used to connect to the negative electrode of the power supply BAT, Both ends are also used to connect loads
  • the control device 200 includes an acquisition module 210, a switching module 220, a calculation module 230, and a drive control module 240.
  • the acquisition module 210 is used to acquire the input voltage and output voltage of the synchronous BUCK circuit 100. And output current, and obtain the current state of the synchronous switch Q2.
  • the obtaining module 210 is also used to obtain the turn-off current threshold when the synchronous switch Q2 is in the on state.
  • the switching module 220 is configured to switch the synchronous switch Q2 to the off state when the output current is less than the turn-off current threshold.
  • the calculation module 230 is configured to calculate the duty cycle of the main switch Q1 according to the input voltage, the output voltage, and the turn-off current threshold.
  • the driving control module 240 is configured to generate a corresponding driving signal according to the duty cycle to control the synchronous BUCK circuit 100.
  • the acquiring module 210 is further configured to acquire the turn-on current threshold when the synchronous switch tube Q2 is in the off state; the switching module 220 is also configured to switch the synchronous switch when the output current is greater than the turn-on current threshold The tube Q2 is turned on; the calculation module 230 is also used to calculate the duty cycle of the main switching tube Q1 according to the input voltage and the output voltage.
  • the synchronous BUCK circuit 100 further includes a loop compensation module, and the loop compensation module is constructed with a corresponding discrete domain differential equation to determine the duty cycle of the main switch Q1 or to solve the duty cycle.
  • the middle volume of the ratio is constructed with a corresponding discrete domain differential equation to determine the duty cycle of the main switch Q1 or to solve the duty cycle.
  • the switching module 220 is also used for when the synchronous switch Q2 is in the on state and the output current is greater than or equal to the turn-off current threshold, or when the synchronous switch Q2 is in the off state and the output When the current is less than or equal to the turn-on current threshold, the current state of the synchronous switch Q2 is maintained.
  • the calculation module 230 is also used to calculate the duty cycle of the main switch Q1 or to calculate the intermediate value of the duty cycle according to the deviation between the output voltage and the reference voltage and the discrete domain differential equation.
  • the drive control module 240 is used to generate a corresponding drive signal according to the duty cycle to control the synchronous BUCK circuit 100, or to obtain the duty cycle according to the intermediate quantity, and then use the duty cycle to generate a corresponding drive signal.
  • the driving signal of controls the synchronous BUCK circuit 100.
  • the embodiment of the application also proposes a synchronous BUCK circuit system.
  • the synchronous BUCK circuit system includes: a synchronous BUCK circuit and a control device, wherein the control device can adopt the control of the synchronous BUCK circuit in the above-mentioned embodiment 2. ⁇ 200 ⁇ Device 200.
  • the synchronous BUCK circuit 100 includes a main switching tube Q1, an inductor L, a synchronous switching tube Q2, an energy storage capacitor C, and a sampling circuit, wherein the first end of the main switching tube Q1 is used to connect to a power supply
  • the positive terminal of BAT, the second terminal is connected to the first terminal of the inductor L, the control terminal is used to connect to the control device 200 in the control device;
  • the first terminal of the synchronous switch tube Q2 is connected to the second terminal of the main switch tube Q1 and the inductor, respectively
  • the first end and the second end of L are used to connect to the negative electrode of the power supply BAT, and the control end is used to connect to the control device 200;
  • the second end of the inductor L is connected to the positive electrode of the energy storage capacitor C, and the negative electrode of the energy storage capacitor C is used to connect to the power supply.
  • the negative pole of BAT and the two ends of the energy storage capacitor C are also used for parallel loads.
  • the sampling circuit is mainly used to sample the input voltage, output voltage, and output current of the synchronous BUCK circuit 100, and input these sampled electrical signals to the control device 200, so that the control device 200 performs the circuit based on the sampled data. control.
  • a voltage divider resistor can be used to sample the corresponding circuit input and output terminals; and for the output current, for example, a current transformer can be used for sampling.
  • an embodiment of the present application also provides an electronic device.
  • the electronic device includes the synchronous BUCK circuit system as in the foregoing embodiment.
  • the electronic device may be a power supply device or the like.
  • each block in the flowchart or block diagram may represent a module, program segment, or part of the code, and the module, program segment, or part of the code contains one or more modules for realizing the specified logical function.
  • Executable instructions may also occur in a different order from the order marked in the drawings.
  • each block in the structure diagram and/or flowchart, and the combination of the blocks in the structure diagram and/or flowchart can be used as a dedicated hardware-based system that performs specified functions or actions. , Or can be realized by a combination of dedicated hardware and computer instructions.
  • the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist alone, or two or more modules may be integrated to form an independent part.

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  • Engineering & Computer Science (AREA)
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Abstract

一种同步BUCK电路的控制方法，包括：获取同步BUCK电路的输入电压、输出电压和输出电流；获取同步开关管当前的状态；在同步开关管为导通状态时，获取关断电流阈值；在所输出电流小于关断电流阈值时，切换同步开关管至关闭状态；根据输入电压、输出电压和关断电流阈值计算主开关管的占空比；根据所述占空比生成相应的驱动信号对同步BUCK电路进行控制。

Description

同步BUCK电路的控制方法、装置、系统和电子装置 技术领域
本申请涉及电路控制技术领域，尤其涉及一种同步BUCK电路的控制方法、装置、系统和电子装置。
背景技术
这里的陈述仅提供与本申请有关的背景信息，而不必然地构成示例性技术。
BUCK电路是一种降压电路，其采用DC-DC电路结构，用于实现直流到直流的降压变换。BUCK电路广泛用在各种电路中，在大电流输出时，为提升效率往往会使用同步管进行续流，其中，在小电流轻载的情况下，为减少无功电流带来的损耗，同步开关管将不工作而使用二极管进行续流，并且小电流轻载时，BUCK电路往往工作在断续工作模式。尤其是当同步管在不同的工作状态切换时，还存在断续模式与连续模式的突然切换，由于两种模式下BUCK电路的输出/输入增益差较大，BUCK电路将产生较大的冲击电流，电路的输出也会出现暂态的过冲或下跌等现象。
发明内容
根据本申请的各种实施例，提供一种同步BUCK电路的控制方法、装置、系统和电子装置。
本申请的实施例提供一种同步BUCK电路的控制方法，包括：
获取所述同步BUCK电路的输入电压、输出电压和输出电流；
获取所述同步BUCK电路中的同步开关管当前的状态；
在所述同步开关管为导通状态时，获取关断电流阈值；
在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
根据所述输入电压、所述输出电压和所述关断电流阈值计算所述同步BUCK电路中的主开关管的占空比；
根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
本申请的实施例提供一种同步BUCK电路的控制方法，包括：
获取所述同步BUCK电路的输入电压、输出电压和输出电流；
获取所述同步BUCK电路中的同步开关管当前的状态；
在所述同步开关管为导通状态时，获取关断电流阈值；
在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
根据所述输入电压、所述输出电压和所述关断电流阈值按照第一占空比公式计算所述同步BUCK电路中的主开关管的占空比；
根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制；
所述第一占空比公式为：
Figure PCTCN2021110805-appb-000001
其中，D为所述主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压；L为所述同步BUCK电路中的电感的电感量；I x为所述关断电流阈值；T s为所述主开关管的开关周期。
本申请的实施例还提供一种同步BUCK电路的控制装置，包括：
获取模块，用于获取采样的所述同步BUCK电路的输入电压、输出电压和输出电流，以及获取所述同步BUCK电路中的同步开关管当前的状态，还用于在所述同步开关管为导通状态时，获取关断电流阈值；
切换模块，用于在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
计算模块，用于根据所述输入电压、所述输出电压和所述关断电流阈值计算所述同步BUCK电路中的主开关管的占空比；
驱动控制模块，用于根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
本申请的实施例提供一种同步BUCK电路系统，包括：同步BUCK电路和控制装置，其中，所述控制装置用于执行同步BUCK电路的控制方法；所述同步BUCK电路包括主开关管、电感、同步开关管、储能电容和采样电路；
所述采样电路用于采集所述同步BUCK电路的输入电压、输出电压和输出电流，并输出至所述控制装置；
所述主开关管的第一端用于连接电源的正极，第二端连接所述电感的第一端，控制端用于连接所述控制装置；
所述同步开关管的第一端分别连接所述主开关管的第二端和所述电感的第一端，第二端用于连接所述电源的负极，控制端用于连接所述控制装置；
所述电感的第二端连接所述储能电容的正极，所述储能电容的负极用于连接所述电源的负极，所述储能电容的两端还用于并联负载；
所述同步BUCK电路的控制方法，包括：
获取所述同步BUCK电路的输入电压、输出电压和输出电流；
获取所述同步BUCK电路中的同步开关管当前的状态；
在所述同步开关管为导通状态时，获取关断电流阈值；
在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
根据所述输入电压、所述输出电压和所述关断电流阈值计算所述同步BUCK电路中的主开关管的占空比；
根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
本申请的实施例提供一种电子装置，所述电子装置包括如前述实施例所述的同步BUCK电路系统。
本申请的一个或多个实施例的细节在下面的附图和描述中提出。本申请的其他特征、目的和优点将从说明书、附图以及权利要求书变得明显。
附图说明
为了更清楚地说明本申请的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本申请的某些实施例，因此不应被看作是对本申请保护范围的限定。在各个附图中，类似的构成部分采用类似的编号。
图1示出了本申请实施例同步BUCK电路的结构示意图。
图2示出了同步BUCK电路的控制方法的第一流程示意图。
图3示出了实施例同步BUCK电路的含环路补偿模块的结构示意图。
图4示出了本申请实施例同步BUCK电路的控制方法的第二流程示意图。
图5示出了本申请实施例同步BUCK电路的控制方法的第三流程示意图。
图6示出了本申请实施例同步BUCK电路的控制装置的结构示意图。
具体实施方式
下面将结合本申请实施例中附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。
通常在此处附图中描述和示出的本申请实施例的组件可以以各种不同的配置来布置和设计。因此，以下对在附图中提供的本申请的实施例的详细描述并非旨在限制要求保护的本申请的范围，而是仅仅表示本申请的选定实施例。基于本申请的实施例，本领域技术人员在没有做出创造性劳动的前提下所获得的所有其他实施例，都属于本申请保护的范围。
除非另有限定，否则在这里使用的所有术语(包括技术术语和科学术语)具有与本申请的各种实施例所属领域普通技术人员通常理解的含义相同的含义。所述术语(诸如在一般使用的词典中限定的术语)将被解释为具有与在相关技术领域中的语境含义相同的含义并且将不被解释为具有理想化的含义或过于正式的含义，除非在本申请的各种实施例中被清楚地限定。
请参照图1和2，本实施例提出一种同步BUCK电路的控制方法，该方法可减少电路中开关管开/关时产生的动态冲击，从而改善电路性能。
示例性地，如图1所示，该同步BUCK电路100包括主开关管Q1、电感L、同步开关管Q2和储能电容C，其中，主开关管Q1的第一端用于连接电源BAT的正极，第二端连接电感L的第一端，控制端用于连接控制装置；同步开关管Q2的第一端分别连接主开关管Q1的第二端和电感L的第一端，第二端用于连接电源的负极，控制端用于连接控制装置；电感L的第二端连接储能电容C的正极，储能电容C的负极用于连接所述电源BAT的负极。储能电容C的两端还用于并联负载R L，以为负载R L提供相应的能量等。
例如，主开关管Q1和同步开关管Q2均可采用MOS管实现。可以理解，上述同步BUCK电路中的同步开关管Q2采用具有低导通电阻的整流MOS管来替代通用BUCK电路中的续流二极管以降低电路中的整流损耗，可大大提高电路转换效率。
应当明白的是，在小电流轻载场合下，图1所示的同步开关管Q2中的体二极管可用于实现同步BUCK电路在断续模式下的续流作用。通常地，上述的同步开关管Q2具有寄生二极管(即体二极管)，在一些其他的情况下，同步开关管Q2中的体二极管还可以采用外置的独立二极管来替代。
考虑到传统的同步BUCK电路在开通与关断同步开关管Q2时，电路存在断续模式和连续模式的突然切换，导致容易产生较大的动态冲击。其中，在断续模式下，当BUCK电 路中流过电感的电流在主开关管Q1关断后的一段时间后逐渐降为0；而在连续模式下，流过电感的电流在每个周期不会降为0。为此，本实施例结合输出电流的大小和同步开关管Q2的状态，在不同的时刻对主开关管Q1的占空比进行预测控制，从而根据预测值对主开关管Q1以及同步开关管Q2进行控制以减少电路中产生的动态冲击。
如图2所示，下面对该同步BUCK电路的控制方法进行详细说明。可以理解，图1中的同步BUCK电路为基础电路，本实施例中的控制方法也可以适用于其他变形的同步BUCK电路。
步骤S110，获取同步BUCK电路100的输入电压、输出电压和输出电流。
示例性地，可通过在对应位置处设置相应的采样电路，如在同步BUCK电路100的输入端设置一采样单元以用于对接入的电源电压V in进行采样，具体地，该采样单元可采用分压电阻和模数转换器(ADC)等构成。对于输出电流Iout和输出电压V out，可在电路的输出端设置另一采样单元进行采样，例如，可采用电流互感器等进行输出电流采样。可以理解，此处的采样电路的具体结构可根据实际需求选取，在此并不作限定。
步骤S120，获取同步开关管Q2当前的状态。
步骤S130，在同步开关管Q2为导通状态时，获取关断电流阈值。
其中，同步开关管Q2的状态为两种，分别是导通状态和关闭状态。其中，导通状态也可以称之为开通状态，关闭状态也可以称之为截止状态或者关断状态。另外，本实施例设置了两个电流阈值，分别是关断电流阈值和开通电流阈值。其中，关断电流阈值小于开通电流阈值，开通电流阈值和关断电流阈值分别决定了同步开关管Q2的开通时刻与关断时刻。
示例性地，若同步开关管Q2当前处于导通状态，则获取关断电流阈值，以用于结合输出电流判断当前是否需要关断该同步开关管Q2。例如，若当前输出电流小于该关断电流阈值，则控制同步开关管Q2由当前的导通状态切换为关闭状态，即步骤S140，否则继续维持当前的导通状态。
步骤S140，在所述输出电流小于关断电流阈值时，切换同步开关管Q2至关闭状态。
步骤S150，根据所述输入电压、所述输出电压和所述关断电流阈值计算主开关管Q1的占空比。
示例性地，当关断同步开关管Q2后，同步BUCK电路进入断续工作模式。此时根据同步BUCK电路断续模式的增益特性，可按照如下的第一占空比公式计算出此时主开关管Q1的占空比。其中，该第一占空比公式为：
Figure PCTCN2021110805-appb-000002
其中，D为主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压；L为同步BUCK电路中电感的电感量；I x为关断电流阈值；T s为主开关管Q1的开关周期。
步骤S160，根据所述占空比生成相应的驱动信号对同步BUCK电路100进行控制。
在计算出主开关管Q1的占空比后，可根据该占空比生成相应的PWM驱动信号以控制主开关管Q1与同步开关管Q2，由于该占空比是根据主开关管Q1接下来的工作模式进行预测的，直接利用该预测的占空比对主开关管Q1进行控制，可以降低主开关管Q1在CCM(连续模式)和DCM(断续模式)两种工作模式切换过程中所产生的电流冲击，进而提高主开关管Q1的可靠性及输出性能。
可以理解，同步BUCK电路在工作在断续模式时，当主开关管Q1开通时，同步开关管Q2断开，此时电感L储能；而当主开关管Q1关断时，电感L上存储的电能通过同步开关管Q2中的体二极管或外置的二极管进行续流。
通常地，同步BUCK电路100可采用多种控制技术进行控制，如电压型控制、平均电流控制或峰值电流控制等，在实际工程中可针对不同的需求选择合适的控制方式。如图3所示，在一实施例中，该同步BUCK电路100还包括环路补偿模块，将采样得到的输出电压V out与预设的参考电压Vref之间的偏差值E作为环路补偿模块的输入，并根据需要输出的电压U用于校正偏差的调整量，从而实现对输出电压的调整。在其他的实施例中，环路补偿模块还可以包括电流环结构，输出电压U作为电流环的给定值，进而根据该给定值以及输出电流进行控制调节后生成相应的占空比控制信号。
其中，该环路补偿模块构建有对应的离散域差分方程，通过该离散域差分方程可以计算出主开关管Q1的占空比或者计算出能够用于求解占空比的中间量。示例性地，该离散域差分方程的表达式为：
U(n)＝A 1U(n-1)+…+A iU(n-i)+B 1E(n)+B 2E(n-1)+…+B jE(n-j)；
其中，U表示占空比或者用于计算得到占空比的中间量；n表示当前采样；n-1表示前一次采样；E表示输出电压与参考电压之间的偏差；i和j均为大于或等于2的整数；A 1、A i、B 1、B 2和B j分别表示对应项的增益系数。可以理解，若不存在其中的某项，则表明对应项的增益系数为0，即差分方程的输出不受该项影响。
如图4所示，进一步地，该同步BUCK电路的控制方法还包括：
步骤S210，在同步开关管Q2为导通状态且所述输出电流大于或者等于所述关断电流 阈值时，维持同步开关管Q2当前的状态。
示例性地，在当前的采样时刻，若同步开关管Q2处于导通状态，同时此时的输出电流大于或等于该关断电流阈值，则控制同步开关管Q2继续为导通状态。而在此阶段，则可根据上述的离散域差分方程计算主开关管Q1的占空比，也即采用传统的占空比确定方式来确定占空比或者用于确定该占用比的中间量。
步骤S220，根据所述输出电压与参考电压之间的偏差以及所述离散域差分方程计算主开关管Q1的占空比或者用于求解所述占空比的中间量。
由于不同的环路补偿结构具有不同的离散域差分方程，具体可根据实际需求来计算占空比或用于求解占空比的中间量。例如，以一电压型控制方式的PID环路补偿结构为例，其对应的差分方程表示为：
U(n)＝U(n-1)+B 1E(n)+B 2E(n-1)+B 3E(n-2)；
其中，U(n)表示当前输出的用于计算得到占空比的中间量，为控制电压；U(n-1)表示前一次的输出，即上一次的历史中间量；E(n)表示当前采样的输出电压与参考电压之间的偏差值；E(n-1)和E(n-2)分别表示前一次和前二次的历史偏差值。
又例如，在另一种电流环PI控制方式中，其对应的差分方程的输出即可直接输出PWM信号的占空比，在此不展开描述。通过计算出占空比后，则可对同步BUCK电路100中的两个开关管进行相应控制。可以理解，对于不同类型的环路控制器，如PI控制、PD控制或PID控制等，其对应的差分方程的表达式也往往不同。
步骤S230，根据所述占空比生成相应的驱动信号对同步BUCK电路100进行控制，或者根据所述中间量求解出占空比后，利用所述占空比生成相应的驱动信号对同步BUCK电路100进行控制。
示例性地，若差分方程能够直接输出占空比，则控制装置可以根据该占空比生成相应的PWM驱动信号，以用于驱动控制主开关管Q1和同步开关管Q2。若差分方向输出的是中间量，如上述的控制电压等，则控制装置可以将其转化为主开关管Q1的占空比，进而输出相应的PWM驱动信号。
进一步地，如图5所示，对于上述步骤S120，由于同步开关管Q2还存在关闭状态的情况，此时则以开通电流阈值为基准，针对不同大小的输出电流，本实施例也将采用不同的方式来计算主开关管Q1的占空比。在上述步骤S120之后，该同步BUCK电路的控制方法还包括：
步骤S310，在同步开关管Q2为关闭状态时，获取开通电流阈值。
步骤S320，在所述输出电流大于所述开通电流阈值时，切换同步开关管Q2至导通状 态。
示例性地，若同步开关管Q2当前处于关闭状态，则获取开通电流阈值，以用于结合输出电流的大小判断当前是否需要开通该同步开关管Q2。例如，若当前输出电流大于该开通电流阈值，则控制同步开关管Q2由当前的关闭状态切换为导通状态，即执行步骤S320，否则继续维持当前的关闭状态。
步骤S330，根据所述输入电压和所述输出电压计算主开关管Q1的占空比。
示例性地，当开通同步开关管Q2后，同步BUCK电路进入连续模式，此时根据BUCK电路的连续模式的增益特性，可按照如下的第二占空比公式计算主开关管Q1的占空比。其中，第二占空比公式为：
Figure PCTCN2021110805-appb-000003
其中，D表示主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压。
步骤S340，根据所述占空比生成相应的驱动信号对同步BUCK电路100进行控制。
在计算主开关管Q1的占空比后，可根据该占空比生成相应的PWM驱动信号以控制主开关管Q1与同步开关管Q2，由于该占空比是根据主开关管Q1接下来的工作模式进行预测的，直接利用该预测的占空比来对主开关管Q1进行控制，可以降低主开关管Q1在模式切换过程中所产生的电流冲击，进而提高主开关管Q1的可靠性及输出的性能。
进一步地，如图5所示，该同步BUCK电路的控制方法还包括：
步骤S410，在同步开关管Q2为关闭状态且所述输出电流小于或等于所述开通电流阈值时，维持同步开关管Q2当前的状态。
步骤S420，根据所述输出电压与参考电压之间的偏差以及所述离散域差分方程计算所述主开关管Q1的占空比或者用于求解所述占空比的中间量。
示例性地，在当前的采样时刻，若同步开关管Q2处于关闭状态，同时此时的输出电流小于或等于该开通电流阈值，则表明还未到开通该同步开关管Q2的时刻，故将维持其当前的关闭状态，直到输出电流大于开通电流阈值时，则控制同步开关管Q2导通。
步骤S430，根据所述占空比生成相应的驱动信号对同步BUCK电路100进行控制；或者，根据所述中间量求解出占空比后，利用所述占空比生成相应的驱动信号对同步BUCK电路100进行控制。
同理，计算出占空比后，则利用该占空比对同步BUCK电路100进行控制，该步骤与上述步骤S230相同，在此不再重复描述。
可选地，在根据上述的第一占空比公式或第二占空比公式计算得到主开关管Q1的占空比的步骤之后，该方法还包括：
根据计算得到的主开关管Q1的占空比调整上述的离散域差分方程中的变量，以使得调整后的离散域差分方程的输出值为所述占空比或用于计算得到所述占空比的中间量。
示例性地，在利用上述的第一占空比公式或第二占空比公式计算出占空比时，由于此时的占空比是由公式直接计算得到，因此，还将根据该占空比调整对离散域差分方程的可调变量进行赋值，如历史输出值U(n-1)、……、U(n-i)等。
可以理解，上述的同步开关管Q2通常在导通与关闭两种状态之间进行切换，而输出电流也在不断变化，本实施例的同步BUCK电路控制方法通过对开关管的控制进行多分支划分，并在不同时刻采用相应的占空比计算公式来给出占空比的预测控制值，可以避免出现大的动态冲击，从而影响开关管的可靠性及输出性能等。
请参照图6，本实施例提出一种同步BUCK电路的控制装置200，用于控制同步BUCK电路以实现功率变换。示例性地，如图1所示，同步BUCK电路100包括主开关管Q1、电感L、同步开关管Q2和储能电容C，其中，主开关管Q1的第一端用于连接电源BAT的正极，第二端连接电感L的第一端，控制端用于连接控制装置200；同步开关管Q2的第一端分别连接主开关管Q1的第二端和电感L的第一端，第二端用于连接电源BAT的负极，控制端用于连接控制装置200；电感L的第二端连接储能电容C的正极，储能电容C的负极用于连接电源BAT的负极，储能电容C的两端还用于并联负载。
示例性地，如图6所示，该控制装置200包括获取模块210、切换模块220、计算模块230和驱动控制模块240，其中，获取模块210用于获取同步BUCK电路100的输入电压、输出电压和输出电流，以及获取同步开关管Q2当前的状态。获取模块210还用于在同步开关管Q2为导通状态时，获取关断电流阈值。切换模块220用于在所述输出电流小于关断电流阈值时，切换同步开关管Q2至关闭状态。计算模块230用于根据所述输入电压、所述输出电压和所述关断电流阈值计算主开关管Q1的占空比。驱动控制模块240用于根据所述占空比生成相应的驱动信号对同步BUCK电路100进行控制。
进一步地，获取模块210还用于在所述同步开关管Q2为关闭状态时，获取开通电流阈值；切换模块220还用于在所述输出电流大于所述开通电流阈值时，切换所述同步开关管Q2至导通状态；计算模块230还用于根据所述输入电压和所述输出电压计算所述主开关管Q1的占空比。
进一步地，所述同步BUCK电路100还包括环路补偿模块，所述环路补偿模块构建有相应的离散域差分方程以确定所述主开关管Q1的占空比或者用于求解所述占空比的中间 量。
于是，切换模块220还用于在所述同步开关管Q2为导通状态且所述输出电流大于或者等于所述关断电流阈值时，或者在所述同步开关管Q2为关闭状态且所述输出电流小于或等于所述开通电流阈值时，维持所述同步开关管Q2当前的状态。计算模块230还用于根据所述输出电压与参考电压之间的偏差以及所述离散域差分方程计算所述主开关管Q1的占空比或者用于求解所述占空比的中间量。而驱动控制模块240则用于根据所述占空比生成相应的驱动信号对所述同步BUCK电路100进行控制，或者根据所述中间量求解出占空比后，利用所述占空比生成相应的驱动信号对所述同步BUCK电路100进行控制。
可以理解，上述实施例1中的可选项同样适用于本实施例，故在此不再重复描述。
本申请实施例还提出一种同步BUCK电路系统，示例性地，该同步BUCK电路系统包括：同步BUCK电路和控制装置，其中，所述控制装置可采用上述实施例2中的同步BUCK电路的控制装置200。
示例性地，如图3所示，同步BUCK电路100包括主开关管Q1、电感L、同步开关管Q2、储能电容C和采样电路，其中，主开关管Q1的第一端用于连接电源BAT的正极，第二端连接所述电感L的第一端，控制端用于连接控制装置中的控制装置200；同步开关管Q2的第一端分别连接主开关管Q1的第二端和电感L的第一端，第二端用于连接电源BAT的负极，控制端用于连接控制装置200；电感L的第二端连接储能电容C的正极，储能电容C的负极用于连接电源BAT的负极，储能电容C的两端还用于并联负载。
本实施例中，采样电路主要用于采样同步BUCK电路100的输入电压、输出电压和输出电流，并将采样得到的这些电信号输入至控制装置200，以使得控制装置200根据这些采样数据进行电路控制。在采样输入电压和输出电压时，例如，可通过分压电阻在对应的电路输入端和输出端采样；而对于输出电流，例如，可通过电流互感器等进行采样。
可以理解，上述实施例中的可选项同样适用于本实施例，故在此不再重复描述。
本申请实施例还提出一种电子装置，示例性地，该电子装置包括如上述实施例的同步BUCK电路系统。例如，该电子装置可以是电源设备等。
在本申请所提供的几个实施例中，应该理解到，所揭露的装置和方法，也可以通过其它的方式实现。以上所描述的装置实施例仅仅是示意性的，例如，附图中的流程图和结构图显示了根据本申请的多个实施例的装置、方法和计算机程序产品的可能实现的体系架构、功能和操作。在这点上，流程图或框图中的每个方框可以代表一个模块、程序段或代码的一部分，所述模块、程序段或代码的一部分包含一个或多个用于实现规定的逻辑功能的可执行指令。也应当注意，在作为替换的实现方式中，方框中所标注的功能也可以以不 同于附图中所标注的顺序发生。例如，两个连续的方框实际上可以基本并行地执行，它们有时也可以按相反的顺序执行，这依所涉及的功能而定。也要注意的是，结构图和/或流程图中的每个方框、以及结构图和/或流程图中的方框的组合，可以用执行规定的功能或动作的专用的基于硬件的系统来实现，或者可以用专用硬件与计算机指令的组合来实现。
另外，在本申请各个实施例中的各功能模块或单元可以集成在一起形成一个独立的部分，也可以是各个模块单独存在，也可以两个或更多个模块集成形成一个独立的部分。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。

Claims (20)

  1. 一种同步BUCK电路的控制方法，包括：
    获取所述同步BUCK电路的输入电压、输出电压和输出电流；
    获取所述同步BUCK电路中的同步开关管当前的状态；
    在所述同步开关管为导通状态时，获取关断电流阈值；
    在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
    根据所述输入电压、所述输出电压和所述关断电流阈值计算所述同步BUCK电路中的主开关管的占空比；
    根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  2. 根据权利要求1所述的方法，其特征在于，所述根据所述输入电压、所述输出电压和所述关断电流阈值计算所述主开关管的占空比时，按照第一占空比公式计算；所述第一占空比公式为：
    Figure PCTCN2021110805-appb-100001
    其中，D为所述主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压；L为所述同步BUCK电路中的电感的电感量；I x为所述关断电流阈值；T s为所述主开关管的开关周期。
  3. 根据权利要求1所述的方法，其特征在于，还包括：
    在所述同步开关管为关闭状态时，获取开通电流阈值；
    在所述输出电流大于所述开通电流阈值时，切换所述同步开关管至导通状态；
    根据所述输入电压和所述输出电压计算所述主开关管的占空比；
    根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  4. 根据权利要求3所述的方法，其特征在于，所述根据所述输入电压和所述输出电压计算所述主开关管的占空比时，按照第二占空比公式计算；所述第二占空比公式为：
    Figure PCTCN2021110805-appb-100002
    其中，D为所述主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压。
  5. 根据权利要求3所述的方法，其特征在于，所述同步BUCK电路还包括环路补偿模块，所述环路补偿模块构建有相应的离散域差分方程以确定所述主开关管的占空比或者用于求解所述占空比的中间量；所述方法还包括：
    在所述同步开关管为导通状态且所述输出电流大于或者等于所述关断电流阈值时，维持所述同步开关管当前的状态；
    根据所述输出电压与参考电压之间的偏差以及所述离散域差分方程计算所述主开关管的占空比或者用于求解所述占空比的中间量；
    根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制，或者根据所述中间量求解出占空比后，利用所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  6. 根据权利要求5所述的方法，其特征在于，所述方法还包括：
    在所述同步开关管为关闭状态且所述输出电流小于或等于所述开通电流阈值时，维持所述同步开关管当前的状态；
    根据所述输出电压与参考电压之间的偏差以及所述离散域差分方程计算所述主开关管的占空比或者用于求解所述占空比的中间量；
    根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制，或者根据所述中间量求解出占空比后，利用所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  7. 根据权利要求5所述的方法，其特征在于，所述离散域差分方程的表达式为：
    U(n)＝A 1U(n-1)+…+A iU(n-i)+B 1E(n)+B 2E(n-1)+…+B jE(n-j)；
    其中，U表示占空比或者用于计算得到所述占空比的中间量；n表示当前采样；n-1表示前一次采样；E表示输出电压与参考电压之间的偏差；i和j均为大于或等于2的整数；A 1、A i、B 1、B 2和B j分别表示对应项的增益系数。
  8. 根据权利要求5所述的方法，其特征在于，所述根据所述输入电压、所述输出电压和所述关断电流阈值计算所述主开关管的占空比的步骤之后，还包括：
    根据计算得到的所述主开关管的占空比调整所述离散域差分方程中的变量，以使得调整后的离散域差分方程的输出值为所述占空比或用于计算得到所述占空比的中间量。
  9. 根据权利要求5所述的方法，其特征在于，所述根据所述输入电压和所述输出电压计算所述主开关管的占空比的步骤之后，还包括：
    根据计算得到的所述主开关管的占空比调整所述离散域差分方程中的变量，以使得调整后的离散域差分方程的输出值为所述占空比或用于计算得到所述占空比的中间量。
  10. 根据权利要求5所述的方法，其特征在于，所述环路补偿模块包括采用PI控制、PD控制或者PID控制的环路控制器。
  11. 一种同步BUCK电路的控制方法，包括：
    获取所述同步BUCK电路的输入电压、输出电压和输出电流；
    获取所述同步BUCK电路中的同步开关管当前的状态；
    在所述同步开关管为导通状态时，获取关断电流阈值；
    在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
    根据所述输入电压、所述输出电压和所述关断电流阈值按照第一占空比公式计算所述同步BUCK电路中的主开关管的占空比；
    根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制；
    所述第一占空比公式为：
    Figure PCTCN2021110805-appb-100003
    其中，D为所述主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压；L为所述同步BUCK电路中的电感的电感量；I x为所述关断电流阈值；T s为所述主开关管的开关周期。
  12. 一种同步BUCK电路的控制装置，包括：
    获取模块，用于获取所述同步BUCK电路的输入电压、输出电压和输出电流，以及获取所述同步BUCK电路中的同步开关管当前的状态，还用于在所述同步开关管为导通状态时，获取关断电流阈值；
    切换模块，用于在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
    计算模块，用于根据所述输入电压、所述输出电压和所述关断电流阈值计算所述同步BUCK电路中的主开关管的占空比；
    驱动控制模块，用于根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  13. 根据权利要求12所述的控制装置，其特征在于，所述计算模块根据所述输入电压、所述输出电压和所述关断电流阈值计算所述主开关管的占空比时，按照第一占空比公式计算；所述第一占空比公式为：
    Figure PCTCN2021110805-appb-100004
    其中，D为所述主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压；L为所述同步BUCK电路中的电感的电感量；I x为所述关断电流阈值；T s为所述主开关管的开关周期。
  14. 根据权利要求12所述的控制装置，其特征在于，
    所述获取模块还用于在所述同步开关管为关闭状态时，获取开通电流阈值；
    所述切换模块还用于在所述输出电流大于所述开通电流阈值时，切换所述同步开关管至导通状态；
    所述计算模块还用于根据所述输入电压和所述输出电压计算所述主开关管的占空比；
    所述驱动控制模块还用于根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  15. 根据权利要求14所述的控制装置，其特征在于，所述计算模块所述根据所述输入电压和所述输出电压计算所述主开关管的占空比时，按照第二占空比公式计算；所述第二占空比公式为：
    Figure PCTCN2021110805-appb-100005
    其中，D为所述主开关管的占空比；V in为当前采样的输入电压；V out为当前采样的输出电压。
  16. 根据权利要求14所述的控制装置，其特征在于，所述同步BUCK电路还包括环路补偿模块，所述环路补偿模块构建有相应的离散域差分方程以确定所述主开关管的占空比或者用于求解所述占空比的中间量；
    所述切换模块还用于在所述同步开关管为导通状态且所述输出电流大于或者等于所述关断电流阈值时，维持所述同步开关管当前的状态；
    所述计算模块还用于根据所述输出电压与参考电压之间的偏差以及所述离散域差分方程计算所述主开关管的占空比或者用于求解所述占空比的中间量；
    所述驱动控制模块还用于根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制，或者根据所述中间量求解出占空比后，利用所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  17. 根据权利要求16所述的控制装置，其特征在于，所述离散域差分方程的表达式为：
    U(n)＝A 1U(n-1)+…+A iU(n-i)+B 1E(n)+B 2E(n-1)+…+B jE(n-j)；
    其中，U表示占空比或者用于计算得到所述占空比的中间量；n表示当前采样；n-1表示前一次采样；E表示输出电压与参考电压之间的偏差；i和j均为大于或等于2的整数；A 1、A i、B 1、B 2和B j分别表示对应项的增益系数。
  18. 根据权利要求16所述的控制装置，其特征在于，所述计算模块在所述根据所述输入电压、所述输出电压和所述关断电流阈值计算所述主开关管的占空比之后，或者在所述 根据所述输入电压和所述输出电压计算所述主开关管的占空比之后，还用于：
    根据计算得到的所述主开关管的占空比调整所述离散域差分方程中的变量，以使得调整后的离散域差分方程的输出值为所述占空比或用于计算得到所述占空比的中间量。
  19. 一种同步BUCK电路系统，包括：同步BUCK电路和控制装置，其中，所述控制装置用于执行同步BUCK电路的控制方法；所述同步BUCK电路包括主开关管、电感、同步开关管、储能电容和采样电路；
    所述采样电路用于采集所述同步BUCK电路的输入电压、输出电压和输出电流，并输出至所述控制装置；
    所述主开关管的第一端用于连接电源的正极，第二端连接所述电感的第一端，控制端用于连接所述控制装置；
    所述同步开关管的第一端分别连接所述主开关管的第二端和所述电感的第一端，第二端用于连接所述电源的负极，控制端用于连接所述控制装置；
    所述电感的第二端连接所述储能电容的正极，所述储能电容的负极用于连接所述电源的负极，所述储能电容的两端还用于并联负载；
    所述同步BUCK电路的控制方法，包括：
    获取所述同步BUCK电路的输入电压、输出电压和输出电流；
    获取所述同步BUCK电路中的同步开关管当前的状态；
    在所述同步开关管为导通状态时，获取关断电流阈值；
    在所述输出电流小于所述关断电流阈值时，切换所述同步开关管至关闭状态；
    根据所述输入电压、所述输出电压和所述关断电流阈值计算所述同步BUCK电路中的主开关管的占空比；
    根据所述占空比生成相应的驱动信号对所述同步BUCK电路进行控制。
  20. 一种电子装置，所述电子装置包括如权利要求19所述的同步BUCK电路系统。
PCT/CN2021/110805 2021-03-11 2021-08-05 同步buck电路的控制方法、装置、系统和电子装置 WO2021254534A2 (zh)

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