WO2017028500A1 - 一种提高开关电源动态响应的控制方法 - Google Patents

一种提高开关电源动态响应的控制方法 Download PDF

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Publication number
WO2017028500A1
WO2017028500A1 PCT/CN2016/072693 CN2016072693W WO2017028500A1 WO 2017028500 A1 WO2017028500 A1 WO 2017028500A1 CN 2016072693 W CN2016072693 W CN 2016072693W WO 2017028500 A1 WO2017028500 A1 WO 2017028500A1
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Prior art keywords
mode
module
output
voltage
dynamic
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PCT/CN2016/072693
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English (en)
French (fr)
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徐申
王冲
范献军
孙伟峰
陆生礼
时龙兴
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东南大学
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Priority to US15/751,136 priority Critical patent/US10097077B2/en
Publication of WO2017028500A1 publication Critical patent/WO2017028500A1/zh

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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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
    • G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/20—Pc systems
    • G05B2219/26—Pc applications
    • G05B2219/2639—Energy management, use maximum of cheap power, keep peak load low
    • 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
    • H02M1/0016—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters
    • H02M1/0019—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters the disturbance parameters being load current fluctuations
    • 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
    • H02M1/0025—Arrangements for modifying reference values, feedback values or error values in the control loop of 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
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33515—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with digital control
    • 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

  • the invention relates to a switching power supply, in particular to a control method for improving the dynamic response of a switching power supply.
  • Switching power supplies are typically used as power supplies for all types of electrical equipment to convert unregulated AC or DC input voltages into regulated AC or DC output voltages. Since the switching power supply needs to be adapted to different operating conditions, the performance requirements for the dynamic response of the power supply are getting higher and higher. Good dynamic effects require a small voltage change and voltage recovery time. For example, in home appliance applications, the power load of the washing machine changes very quickly, so that the output voltage of the power supply introduces overvoltage and undervoltage.
  • the general power supply selects the multi-mode control method, and the multi-mode control method introduces the problem of the dynamic performance degradation.
  • the switching frequency is usually reduced to reduce the circuit loss.
  • 1A load load A
  • switching frequency f A is 70kHz
  • circuit has high efficiency
  • 0.7A load is load B
  • switching frequency f B is 70kHz
  • 0.2A load load C
  • switching frequency f C is 20kHz
  • the 0.05A load is the load D
  • the switching frequency f D is 20 kHz
  • the switching frequency selection of the load point is selected according to the system efficiency requirement.
  • the PWM mode When the load is between AB, the PWM mode is adopted, the load is between BC, the PFM mode is adopted, the load is between CDs, the PWM mode is adopted, and the DPWM mode is used.
  • the load is less than the load D, the PWM mode is adopted.
  • DPFM mode the duty mode of the load from light to heavy is DPFM-DPWM-PFM-PWM. If the load is standby, according to the size of the dummy load, the standby frequency is assumed to be 2 kHz. At this time, the control mode is DPFM mode. If the load suddenly changes to full load, the output voltage drops at a very fast speed.
  • the control mode will be respectively After DPWM, PFM, PWM mode, when the compensation result does not reach the full load condition, the output voltage is always falling, which may cause a serious voltage drop, which can not be tolerated under certain conditions; the same is switched to full at full load.
  • the intermediate mode control process will cause the voltage to rise continuously, and the voltage will cause a large overshoot.
  • the control mode switches back and forth between the two modes, and switching from one mode to another requires several cycles to confirm that switching mode control is required. Under such conditions, the dynamic effect will be further reduced.
  • sampling can only be done once in one cycle.
  • the output voltage can only be sampled before the secondary current drops to zero. So when the load is lightly weighted, the DPWM switch The frequency is low, even if the PI adjustment is large, but the dynamic process is slower to ensure stability.
  • the present invention proposes a control method for improving the dynamic response of a switching power supply, which can limit the overshoot and undervoltage of the output voltage within a certain range, and reduce the dynamic response time and improve the dynamics. Performance, in the multi-mode control will not cause system instability, making the circuit design dynamic performance is better.
  • a control method for improving dynamic response of a switching power supply is characterized in that: the control system and the controlled switch are based on a control system including a sampling module, a dynamic control module, an error calculation module, a PID module, a mode control module, and a PWM module.
  • the power sources are connected to form a closed loop;
  • the sampling module comprises a sampling circuit and a sampling calculation module, and the sampling circuit obtains the information of the output voltage by dividing the output of the switching power supply, and the sampling calculation module calculates the signal Vo of the output voltage according to the result of the sampling circuit;
  • the dynamic control module comprises a voltage monitoring module and a slope calculation module; the voltage monitoring module receives the sampling result Vo output by the sampling module and according to the size of Vo and the set Vo upper limit value Vomax, Vo lower limit value Vomin and the reference voltage Vref Relationship, judging whether to adopt dynamic mode, wherein Vomin ⁇ Vref ⁇ Vomax; dynamic mode means that when the output voltage Vo changes greatly, the output voltage Vo is quickly returned to the stable voltage by inputting high power or low power, and the dynamic mode includes Constant frequency light load cut heavy load LTH mode and constant frequency heavy load cut light load HTL mode;
  • the voltage monitoring module outputs the mode selection result mode_F to the mode control module and the slope calculation module. If the voltage monitoring module determines that the system enters the dynamic mode, the slope calculation module calculates the slope of the voltage change; if the normal operation mode, controls the output lock of the slope calculation module.
  • the slope calculation module calculates the rising slope of Vo when the voltage monitoring module outputs the LTH mode; when the voltage monitoring module outputs the HTL mode, calculates the slope of the Vo drop; when the normal operating mode is used, the slope calculation module does not calculate the slope, the slope Kslope Keep unchanged; the result of the slope calculation module Kslope is output to the mode control module;
  • the voltage monitoring module contains three comparators COMP1, COMP2 and COMP3 and a logic unit.
  • the positive end of the comparator COMP1 is connected to the Vo upper limit value Vomax, the negative terminal is connected to Vo;
  • the positive terminal of the comparator COMP2 is connected to Vo, the negative terminal is connected to the set reference voltage Vref;
  • the positive terminal of the comparator COMP3 is connected to Vo, negative
  • the Vo lower limit value Vomin of the terminal connection setting, the logic unit unit outputs one of three modes of the LTH mode, the HTL mode, and the normal mode according to the results of the three comparators:
  • the logic unit When Vo is smaller than the lower limit voltage Vomin, the logic unit outputs a light-loaded heavy-duty LTH mode of constant frequency in the dynamic mode, and the output is quickly risen to the reference voltage Vref by inputting high power, and then jumps out of the mode, and enters the normal mode, starting from the normal mode.
  • the initial state is given by the mode control module;
  • the logic unit When Vo is larger than the upper limit voltage Vomax, the logic unit outputs a constant frequency heavy-duty switching light load HTL mode in the dynamic mode, and the output is quickly dropped to the reference voltage Vref by inputting a small power, and then jumps out of the mode to enter the normal mode, starting from the normal mode.
  • the initial state is given by the mode control module;
  • the input of the slope calculation module is the sampling result Vo and the output mode_F of the voltage monitoring module.
  • the mode_F is in the LTH mode
  • Vo(n) is the sampling result of the current period
  • Vo(n-N1) is the sampling result before N1 cycles
  • Kup is the result of the output slope calculation module Kslope
  • mode_F is the normal mode
  • the output result Kslope remains unchanged through the latch;
  • the input of the error calculation module is the output Vo of the sampling module, and the difference of the output voltage Vo is subtracted according to the calculated reference voltage Vref, that is, the current sampling error, denoted as e1, and output to the PID module;
  • the input of the mode control module is the output mode_F of the voltage monitoring module, the output Kslope of the slope calculation module, and the operation result V PI of the PID module.
  • the mode control module turns off the PID by outputting the control signal PI_ctrl.
  • the module controls the switching period of the dynamic mode of the PWM module receiving mode control module T s_LTH or T s_HTL and the duty ratio D LTH / current or D HTL / current information, and the PWM module is now switched according to the dynamic mode T s_LTH or T s_HTL and duty cycle D LTH / current or D HTL / current information to generate a duty cycle waveform; when the mode control module jumps out of the dynamic mode into the first switching cycle of the normal operating mode, the mode control module calculates the module according to the slope at this time The slope size Kslope obtains the corresponding output load size. Through the control signal PI_ctrl, the PID module is turned on and the current sampling result is assigned V PI0 before the PID calculation.
  • V PI0 is the output value of the PID module corresponding to the load in the steady state after the load change.
  • the PID module performs PID calculation based on the output error of the error module, PID operation If V PI feedback control module to the mode selection mode and the normal operation control mode; when the mode control module out in a dynamic mode to enter the normal operating mode and a second subsequent switching cycles, PI_ctrl turn calculates the PID module, according to the PID module The output error of the error module is PID-operated, and the operation result V PI is fed back to the mode control module for mode selection and control in the normal working mode.
  • the PWM module receives the compensation result of the PID output V PI and the mode control module gives The control mode of the normal working mode is recorded as mode_ctrl, and the switching period and the duty cycle/current information are obtained through calculation, and the PWM module generates a duty cycle waveform according to the switching period and the duty ratio signal;
  • the PID module input is the error signal e1 output by the error calculation module, the control signal PI_ctrl output by the mode control module, and the assignment V PI0 .
  • the PID module is turned off, and when the dynamic mode is switched to the first switching cycle of the normal operation mode, first The initial value V PI0 is assigned to the PID module operation, and then the PID operation is performed, and the compensation result V PI is output to the mode control module and the PWM module, and then the PID operation is performed every cycle of the normal operation mode, and the compensation result V PI is output to the mode control module.
  • PWM module PWM module
  • the input of the PWM module is the PI_ctrl control signal output by the mode control module, the switching period T s_LTH or T s_HTL of the LTH and HTL modes, the duty ratio D LTH or D HTL , the control mode result mode_ctrl of the mode control module in the normal operation mode, and
  • the compensation result of the PID module V PI is calculated by the PID module compensation result V PI and the control mode mode_ctrl signal of the normal operation mode given by the mode control module to obtain the information of the switching period and the duty ratio during normal control, and obtain the period and duty ratio.
  • the duty cycle waveform is outputted by the driving circuit to implement loop control on the gate of the switching power supply power tube; then the output voltage of the switching power supply is sampled again, and the above process is repeated to cyclically control the switching power supply power tube. Turning on and off to make the system more stable, resulting in a higher dynamic response.
  • the dynamic control method proposed by the invention can cut the light load mode by the heavy load of the small energy when the output voltage exceeds the upper limit voltage, so that the output is fast and stable, and when the output voltage is lower than the lower limit voltage, the light load is cut by the large energy.
  • the heavy-duty mode makes the output fast and stable, and the change of the output voltage during load switching is limited between the upper limit voltage and the lower limit voltage. The voltage change is greatly reduced, and the dynamic recovery time is greatly reduced.
  • the dynamic control method proposed by the present invention calculates the slope of the output voltage change in the heavy load cut light load mode and the light load cut heavy load mode, and obtains the load size according to the one-to-one monotonic relationship between the slope and the load. After jumping out of the above two modes, it jumps to the working state of the corresponding load point. After the jump, the energy and load steady-state consumption are not much different, eliminating subsequent voltage oscillations and reducing the dynamic recovery time.
  • the slope is used to determine the magnitude of the load after the jump, which can avoid the large voltage resonance caused by the large difference between the energy and the steady-state consumption of the load after the jump, so that the heavy load cut light load mode, the light load cut heavy load mode and the normal mode generate The oscillations make the circuit more stable.
  • the invention increases the two modes of operation of the heavy-duty cut light load mode and the light load-cut heavy load mode, and the method of determining the operating point by the slope does not affect the stability of the general multi-mode design loop.
  • the invention can improve the flexibility of the circuit design. Due to the slope and mode time relationship between the heavy load mode and the light load mode, the mode time can replace the voltage slope function, and the voltage slope and mode time can be applied. In analog design and digital design, the application control is more extensive, and the dynamic response of the circuit is improved.
  • the invention can be applied to all kinds of switching power supply circuit structures, and has universality, reusability and portability;
  • FIG. 1a is a block diagram of a system structure of a control method of the present invention
  • FIG. 1b is a block diagram of a voltage monitoring module of FIG. 1a
  • FIG. 1c is a block diagram of a slope calculation module of FIG. 1a;
  • FIG. 2 is a schematic diagram of an application of a heavy-duty cut light load HLT mode
  • Figure 3 is a schematic diagram of the application of the light load-cut heavy-duty LTH mode
  • FIG. 4a is a block diagram of a closed loop circuit configuration diagram of a multimode controlled flyback converter of the present invention
  • FIG. 4b is a diagram showing the relationship between the switching frequency and the load current when the flyback system operates in a normal operating mode in a steady state.
  • FIG. 5 is a graph showing the dynamic response of the flyback flyback circuit of FIG. 4 during multi-mode control at load switching, and FIG. 5a is a dynamic result before the load is switched from 700 ⁇ to 5 ⁇ without using the dynamic method of the present invention;
  • FIG. 5b is When the load is switched from 700 ⁇ to 5 ⁇ , the dynamic results of the dynamic method are used.
  • Figure 5c shows the dynamic results before the dynamic method is used when the load is switched from 5 ⁇ to 700 ⁇ .
  • Figure 5d shows the load switched from 5 ⁇ . When it reaches 700 ⁇ , the dynamic results after the dynamic method of this paper are adopted;
  • FIG. 6 is a flyback flyback circuit of FIG. 4, when the control method jumps out of the LTH mode, FIG. 6a shows the dynamic effect when the initial working state is fixed to full load, and FIG. 6b shows the dynamic effect of the initial working state by the slope Kup;
  • FIG. 7 is a flyback flyback circuit of FIG. 4.
  • FIG. 7a shows the dynamic effect when the initial working state is fixed to standby
  • FIG. 7b shows the dynamic effect of the initial working state with the slope Kdown.
  • the solid arrow is the signal flow used by the control loop in normal operation mode
  • the dashed arrow and solid arrow are the signal flow in the control loop in dynamic mode.
  • the invention improves the control method of the dynamic response of the switching power supply, and is based on a control system comprising a sampling module, a dynamic control module, an error calculation module, a PID module, a mode control module and a PWM module, and the control system is connected with the controlled switching power supply. a closed loop;
  • the sampling circuit in the sampling module samples the output voltage of the switching power supply, and the output voltage information is input to the sampling calculation module.
  • the sampling calculation module obtains the signal Vo of the output voltage according to the sampling algorithm, and inputs the current sampling voltage Vo into the dynamic control module.
  • the error calculation module calculates the current voltage error.
  • the dynamic control module includes a voltage monitoring module and a slope calculation module.
  • the voltage monitoring module determines whether to adopt the dynamic mode according to the sampling result Vo.
  • the so-called dynamic mode is that when the load voltage changes greatly, the upper limit voltage Vomax and the lower limit voltage Vomin are set here, and when Vo is greater than Vomax or Vo is less than Vomin, the voltage change is considered to be very high. Large, the input voltage needs to be quickly returned to the stable voltage by inputting high power or low power.
  • the output voltage is smaller than the lower limit voltage Vomin, the light-loaded heavy-duty mode (LTH) of constant frequency is introduced in the dynamic mode.
  • the input high power causes the output to rise rapidly to the reference voltage Vref and then jump out of the mode.
  • the heavy-duty cut light load mode (HTL) of the constant frequency in the dynamic mode is introduced, and the output is made by inputting low power. After falling rapidly to the reference voltage Vref, the mode is jumped.
  • the loop control by the normal PI control method and the mode control is called the normal operation mode; the voltage monitoring module
  • the output mode result (mode_F) is input to the mode control module and the slope calculation module. If the voltage monitoring module determines that the system enters the dynamic mode, the slope calculation module calculates the slope of the voltage change. If the operating mode is normal, the output latch of the control slope calculation module does not change.
  • the slope calculation module calculates the rising slope of the voltage when the voltage monitoring module outputs the LTH mode. When the HTL mode is output, the slope of the voltage drop is calculated. When the normal operating mode is used, the slope is not calculated and the output remains unchanged.
  • the result of the slope calculation module Kslope is input to the mode control module.
  • the input of the mode control module is the mode output (mode_F) of the voltage monitoring module, the output slope Kslope of the slope calculation module, and the operation result V PI of the PID module.
  • mode_F mode output
  • Kslope the output slope
  • V PI the operation result
  • the voltage monitoring module outputs mode_F to the dynamic mode (LTH mode or HTL mode)
  • the module outputs a control signal PI_ctrl to turn off the PID module, and controls the PWM module to receive the dynamic mode switching period T s_LTH or T s_HTL and the duty ratio of the module output.
  • the PWM module generates a duty cycle waveform according to the two signals at this time; when the mode control module jumps out of the dynamic mode to enter the first switching cycle of the normal working mode, the mode control module according to the The slope of the slope calculation module Kslope obtains the corresponding output load size.
  • the control signal PI_ctrl By outputting the control signal PI_ctrl, the PID module is turned on and the current sampling result is assigned V PI0 before the PID calculation, and V PI0 is the load after the load changes in the steady state.
  • the output value of the corresponding PID module after the assignment, the PID module performs PID calculation according to the output error of the error module, and the PID operation result V PI is fed back to the mode control module for mode selection and control in the normal working mode; when the mode control module is jumping out of the dynamic The mode enters the second switching cycle of the normal operating mode and after, the output control No.
  • PI_ctrl Open PID module operation, the PID module PID calculation based on an output error error module, the operation result V PI fed back to the mode control module mode selection and control of the normal operation mode, the normal operating mode, the PWM module receives PID
  • the output compensation result V PI and the control mode (mode_ctrl) selected by the mode control module for normal operation mode are calculated to obtain the switching period and duty cycle (or current) information, and the PWM module generates a duty according to the signals of the two at this time.
  • the PID module input is the error signal output by the error calculation module, and the control signal PI_ctrl output by the mode control module is assigned V PI0 .
  • PI_ctrl controls the PID module to be turned off.
  • the PID operation is first assigned to the initial value V PI0 , and then the PID operation is performed to compensate the calculation result.
  • the V PI input mode control module and The PWM module after each cycle of the normal operating mode, enters the PID operation, and the compensation result V PI is input to the mode control module and the PWM module.
  • the PWM module selects the switching period T s_LTH or T s_HTL and the duty ratio D LTH or D HTL (or current) information of the dynamic mode according to the control signal PI_ctrl outputted by the mode control module or compensates the result V PI and the mode control module by the PID module.
  • the mode signal mode_ctrl of the normal working mode is calculated to obtain the information of the switching period and the duty ratio during normal control, and after obtaining the period and duty ratio (or peak current) information, the duty cycle waveform is output through the driving circuit to realize loop control.
  • the dynamic control module when the load changes greatly, the dynamic response of the switching power supply is improved; then the output voltage of the switching power supply is sampled again, and the above process is repeated to cyclically control the opening and closing of the switching power supply power tube, so that The system is more stable, resulting in a higher dynamic response.
  • the sampling module includes a sampling circuit, a sampling calculation module, and the sampling circuit obtains information of the output voltage through output voltage division, and the sampling calculation module gives the sampling circuit control signal and the output voltage Vo according to the result of the sampling circuit.
  • the sampling here can be direct sampling or indirect sampling, and the sampling result can be analog or digital.
  • the dynamic control module includes a voltage monitoring module and a slope calculation module.
  • the voltage monitoring module determines whether to adopt the dynamic mode according to the sampling result Vo.
  • the voltage monitoring module includes three comparators and a logic unit to determine whether to adopt the dynamic mode, and the three comparators respectively determine the sampling voltage Vo and the lower limit voltage Vomin, and the sampling voltage Vo And the upper limit voltage Vomax, the relationship between the sampling voltage Vo and the reference voltage Vref, the logic unit outputs the mode selection result according to the comparator result, and the output result mode_F is the HTL mode (mode_LTH), the LTH mode (mode_HTL), the normal working mode (mode_normal) One of the three, when Vo is greater than Vomax, the output mode_F is mode_HTL, which starts the HTL mode.
  • the output mode_F is mode_LTH, that is, the LTH mode is started.
  • Vo is between Vomin and Vref
  • the period on the logic unit is LTH mode
  • the output of this cycle is LTH mode.
  • the upper cycle is HTL mode
  • the output of this cycle is Normal working mode
  • the upper cycle is the normal working mode
  • the output of this cycle is the normal working mode.
  • the upper cycle In the HTL mode
  • the output of this cycle is the HTL mode.
  • the output of this cycle is the normal working mode.
  • the mode selection result is input to the slope calculation module and the mode control module in the dynamic module.
  • the input of the slope calculation module is the sampling result Vo and the output mode mode_F of the voltage monitoring module. If the output is in the LTH mode, the rising slope Kup of Vo is calculated.
  • Kdown is the size of the output Kslope, when the voltage When the output mode of the monitoring module is normal operation mode, the module does not work, and the output result Kslope remains unchanged through the latch.
  • the output of this module, Kslope is input to the mode control module.
  • the error calculation module input is the output Vo of the sampling circuit, and the difference of the output voltage Vo is subtracted according to the calculated reference voltage Vref, that is, the current sampling error, denoted as e1, and input to the PID module. Or with duty cycle or
  • the input of the mode control module is the output mode mode_F of the voltage monitoring module and the output Kslope of the slope calculation module.
  • the output mode (mode_F) of the voltage monitoring module is LTH mode (mode_LTH)
  • the module outputs a control signal PI_ctrl, which is input to the PID module and the PWM module.
  • PI_ctrl turns off the PID module and controls the PWM signal to receive the LTH output by the module.
  • PI_ctrl is PI_off;
  • the module when the output mode (mode_F) of the voltage monitoring module is HTL mode (mode_HTL), the module outputs a control signal PI_ctrl, Input to the PID module and the PWM module, at this time PI_ctrl closes the PID module and controls the PWM signal to receive the HTL mode switching cycle size T s_HTL and the duty ratio D HTL (or current) of the module output, and note that PI_ctrl is PI_off;
  • the output mode (mode_F) of the voltage monitoring module is the normal operation mode (mode_normal)
  • the module outputs a control signal PI_ctrl, which is input to the PID module and the PWM module, at which time PI_ctrl is recorded as PI_set, start the PID module
  • the module outputs the control signal PI_ctrl, which is input to the PID module and the PWM module.
  • PI_ctrl is recorded as PI_on
  • the PID module is started to perform PID operation
  • the PWM module is controlled to receive the PID. results V PI compensation module, and receives a control V PI normal operation mode according to V PI, the normal operating mode of the mode selection result (mode_ctrl) is input to the PID parameter selection module and PWM module,
  • the PID module includes a PID calculation function and a PID parameter selection function.
  • the PID module operates under the control of the control signal (PI_ctrl) output by the mode control module and the mode selection result (mode_ctrl) of the normal operation mode.
  • PI_ctrl When PI_ctrl is PI_off, the PID module is closed;
  • PI_ctrl is PI_set, V PI is assigned by V PI0 output by the mode control module, and the PID operation parameter is selected according to the mode selection result (mode_ctrl) of the normal working mode, including the proportional parameter Kp, the integral parameter K i , and the differential parameter K d for PID.
  • the input of the PWM module is the control signal PI_ctrl output by the mode control module, the switching period T s_LTH or T s_HTL of the LTH and HTL modes and the duty ratio D LTH or D HTL , and the mode selection result (mode_ctrl) signal of the normal operation mode, PID
  • the compensation result of the module is V PI .
  • mode_ctrl and the compensation result V PI of the PID module, according to the result of mode_ctrl, select a reasonable method to obtain the switching period and duty cycle (or peak current) of the normal mode through V PI calculation; obtain the period and duty ratio (or peak current) After the information, the duty cycle waveform is obtained, and the output of the PWM unit is connected to the driving circuit.
  • the driving circuit selects a circuit with a small delay time as much as possible, and the output of the driving circuit is connected to the gate of the switching power supply power tube.
  • the LTH mode is adopted when the output voltage is lower than Vomin. If the PID adjustment is used, as indicated by the thick dotted line, the voltage will still drop after the output voltage drops to Vomin, and the dynamic recovery time is also very long.
  • LTH mode when the output voltage is lower than Vomin, the LTH mode is used immediately. Since the energy of this mode is generally greater than the full load energy, the output voltage starts to rise immediately and will not decrease any more.
  • the output load can be obtained by the slope size, so that the operating mode energy of the jump out of the LTH mode is similar to the load power consumption, and the resonance introduced by the subsequent energy is not matched, such as the solid line. It can be seen that if the LTH mode is jumped out, if the working state starts from full load, the input energy is too large, and the voltage resonance is introduced, as indicated by a thin dotted line.
  • the output load can be obtained by the slope size, so that the working mode energy of the HTL mode is similar to the load power consumption, and the resonance introduced by the subsequent energy mismatch is removed, as shown by the solid line; it can be seen that if the HTL mode is jumped out, if the working state is Standby starts, its input energy is low, and the voltage is induced to resonate as shown by the thin dotted line.
  • Fig. 4a is an embodiment in which a flyback circuit is targeted.
  • the method and system used in the present invention can also be applied to other types of switching power supply circuit structures.
  • the back-side feedback circuit is taken as an example.
  • the input of the flyback converter example is 90 ⁇ 265V, the output is 5V, the current is up to 1A, the inductance is 1.6mH, the transformer turns ratio is 104/6, and the output is constant voltage.
  • the converter adopts the DCM control method to realize digital control through multi-mode control method.
  • the working mode of the existing circuit under different loads is given below. On the basis of this mode, the working method of optimizing dynamic performance in this example is added.
  • the mode control method from light load to heavy load is DPFM-DPWM-PFM-PWM as shown in Figure 4b.
  • the switching frequency is 70kHz; the load is between BC, adopt PFM mode, the primary peak current is 0.255A; the load is between CD, adopt DPWM mode, denoted as DPWM Mode, the switching frequency is 20kHz; when the load is less than the load D, the PWM mode is adopted, which is recorded as DPFM mode, and the primary peak current is 0.151A.
  • the duty mode of the load from light to heavy is DPFM-DPWM-PFM-PWM.
  • the standby load is 700 ⁇ , and the standby circuit operates in DPFM mode.
  • the primary peak current is 0.151A and the switching frequency is 3kHz. When the load is 5 ⁇ , the primary peak current is 0.365A and the switching frequency is 70kHz.
  • LTH light load-cut heavy-duty mode
  • this condition needs to be given under the condition of minimum input voltage;
  • the primary side peak current takes a larger value, generally greater than or equal to the peak current of the full load And then meet the requirements of DCM work and calculation margins
  • increase the switching frequency In this example, the first method is taken as an example, and the primary side peak current is 0.4 A, and the switching period is 70 kHz.
  • HTL heavy-duty cut light load mode
  • this mode is a control method in which the period is fixed and the primary peak current is fixed.
  • the primary current is the same as the DPFM mode, and the switching frequency is as low as possible, but the system needs to be guaranteed.
  • the auxiliary winding waveform will not be deformed because the RCD clamp voltage is too low, which causes a large error in the sampling of the output voltage.
  • This condition needs to ensure that the clamping voltage of the RCD circuit at this time is sufficiently high; Yes, the primary peak current is less than the peak current of the DPFM, and the switching frequency is reduced as much as possible.
  • This method also requires a sufficiently high clamping voltage of the RCD circuit to enable accurate sampling of the light load.
  • the first method is taken as an example, and the primary side peak current is 0.151 A, and the switching period is 2 kHz.
  • the primary inductance L p 1.6mH
  • ⁇ is the system efficiency of 0.8
  • I o (n) is the output load current.
  • the sampling result V(n-5) before the five cycles is subtracted from the current period sampling result V(n) as the magnitude of the slope, and when the load is switched from light load to heavy load, LTH is called, the output load and its corresponding working state and slope relationship are shown in Table 1, so for example, when the light load is switched to the heavy load 7 ⁇ , when the output voltage reaches 5V, jump out of the LTH mode, enter the PFM mode, start
  • the working state is 350 clocks (57 kHz) and the primary peak current is 0.286 A, so that the output does not introduce large ripple.
  • the output voltage is digitally sampled, and the digital quantity corresponding to 5V is 583, and Kup is calculated by the digital value.
  • ⁇ is the system efficiency of 0.6
  • I o (n) is the output load current.
  • the current period sampling result V(n) is subtracted from the sampling result V(n-3) five cycles as the magnitude of the slope, and it can be obtained when the load is cut from heavy load to light load.
  • HTL is called, the output load and its corresponding working state and slope relationship are shown in Table 2, so for example, when the load is switched from heavy load to light load 500 ⁇ , when the output voltage reaches 5V, jump out of HTL mode and enter DPFM mode.
  • the initial operating state is a period of 4330 clocks (4.62 kHz) with a primary peak current of 0.151 A, so that the output does not introduce large ripple.
  • the output voltage is digitally sampled, and the digital quantity corresponding to 5V is 583, and Kdown is calculated by the digital value.
  • FIG. 5 is a graph showing dynamic response of a general multi-mode control method of the flyback flyback circuit of FIG. 4 during load switching; and a dynamic response curve using a technique for improving dynamic response; this is an embodiment of the present invention
  • Figure 5a shows the dynamic results before the load is switched from 700 ⁇ to 5 ⁇ without using the dynamic method of this paper.
  • Figure 5b shows the dynamic results of this example when the load is switched from 700 ⁇ to 5 ⁇ .
  • the output voltage undervoltage is 1.3V
  • the recovery time is 11.86ms.
  • the voltage undervoltage is 0.332V
  • the recovery time is 0.932ms
  • the dynamic performance is greatly improved.
  • Figure 5c shows the dynamic results before the load is switched from 5 ⁇ to 700 ⁇ .
  • Figure 5d shows that when the load is switched from 5 ⁇ to 700 ⁇ , the output voltage overvoltage is 0.584V and the recovery time is 126.3. Ms, after adopting this technology, the output voltage overvoltage is 0.152V, the recovery time is 43.4ms, and the dynamic performance is greatly improved. The dynamic results of this example have been greatly improved.
  • Figure 6 is a diagram showing that the operating state is fixed to full load and slope when the LTH mode is jumped out of the flyback flyback circuit of Figure 4. Kup to determine the comparison of the working states; this is an embodiment of the invention. It can be seen that when the load is switched from 700 ⁇ to 7 ⁇ , when the system output reaches 5V and jumps out of the LTH mode, in Figure 6a, the adjustment starts at the full load. At this time, the input power is greater than the load power consumption, and the output voltage will rise. Introducing voltage oscillation; in Figure 6b, when jumping out of LTH mode, kup is 6, and the corresponding load is about 7 ⁇ .
  • the working state starts from PFM mode, the period is 350 clocks (57kHz), and the primary peak current is 0.286A.
  • the voltage oscillation is introduced.
  • the output voltage can be considered to have stabilized, and the subsequent resonance voltage is removed, and the recovery time of the dynamic process is reduced.
  • FIG. 7 is a comparison of the working state to the standby state and the operating state with the slope Kdown when the HLT mode is jumped out of the flyback flyback circuit of FIG. 4, which is an embodiment of the present invention. It can be seen that when the load is switched from 5 ⁇ to 100 ⁇ , when the system output reaches 5V and jumps out of the HTL mode, in Figure 7a, the adjustment starts in the standby working state. At this time, the input power is less than the load power consumption, and the output voltage will drop. Voltage oscillation is introduced; in Figure 7b, when HTL mode is jumped, Kdown is 5, and the corresponding load is about 100 ⁇ .
  • the working state starts from DPWM mode, the cycle is 1000 clocks (20kHz), and the primary peak current is 0.151A.
  • the voltage oscillation is introduced.
  • the output voltage can be considered to have stabilized, and the subsequent resonance voltage is removed, and the recovery time of the dynamic process is reduced.

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Abstract

一种提高开关电源动态响应的控制方法，基于包括采样模块、动态控制模块、误差计算模块、PID模块、模式控制模块以及PWM模块构成的闭环控制系统，采样模块采样输出电压Vo，动态控制模块根据输出电压Vo的大小分别与设定的上限电压Vomax、下限电压Vomin以及参考电压Vref进行比较，判断是否采用动态模式，动态模式下当输出电压Vo变化很大时，通过输入大功率或小功率的方法使得输出电压Vo快速返回到稳定电压。

Description

一种提高开关电源动态响应的控制方法 技术领域
本发明涉及开关电源，尤其涉及一种提高开关电源动态响应的控制方法。
背景技术
开关电源通常作为各类用电设备的电源，起到将未调整的交流或直流输入电压变换为调整后的交流或直流输出电压。由于开关电源需要适应于不同的工作条件，对电源的动态响应的性能要求越来越高。好的动态效果要求与有小的电压变化以及电压恢复时间。举例而言在家电应用中，洗衣机的电源负载变化很快很大，这样电源输出电压引入过压与欠压，当过压与欠压过大时对洗衣机的负载伤害较大；另外在手机充电中，当充电器待机，手机突然加载，输出电压降低，当降低到电池的正常电压下，对电池有一定的伤害，因此动态性能需要提高。
在现在的电源管理中，为了使得电源有较高的效率，一般的电源选择多模式的控制方法，多模式控制方法会引入动态性能下降的问题。下面以5V，1A输出的反激变换器为例，当负载功耗减小时，为了减小电路损耗通常会减小开关频率。定义1A负载，为负载A，开关频率fA为70kHz，电路具有较高的效率，0.7A负载为负载B，开关频率fB为70kHz，0.2A负载为负载C，开关频率fC为20kHz，0.05A负载为负载D，开关频率fD为20kHz，负载点的开关频率选择是根据系统效率要求而选择的。当负载介于AB之间，采用PWM模式，负载介于BC之间，采用PFM模式，负载介于CD之间，采用PWM模式，记为DPWM模式，负载小于负载D时，采用PWM模式，记为DPFM模式，负载从轻到重的工作模式为DPFM-DPWM-PFM-PWM。若负载为待机时，根据假负载的大小，假定待机频率为2kHz，此时控制模式为DPFM模式，若负载突然改变为满载，输出电压以很快的速度下降，根据补偿结果控制模式将会分别经过DPWM，PFM，PWM模式，在补偿结果未达到满载的条件时，输出电压是一直在下降的，这可能造成严重电压下降，在有的条件下式无法忍受的；同样的在满载切换到轻载时，中间的模式控制过程会造成电压的持续上升，电压会产生很大的过冲。另外，在有的条件下，为了防止模式切换时，在切换点附近，控制模式在两个模式之间来回切换，从一个模式切换到另一个模式需要经过几个周期来确认需要切换模式控制，这种条件下，动态的效果会进一步降低。
此外，在一些控制中，只能在一个周期采样一次，例如在原边反馈的反激电源中，输出电压在只能在次级电流下降到零之前来采样。这样当负载由轻切重时，DPWM的开关 频率低，即使PI调整很大，但为了保证稳定性，动态过程更加缓慢。
另外，有的控制方法为了加快动态响应的速度，会提高PI参数来加快补偿，以此来提高动态效果，但在多模式控制对提高动态性能效果改善不大。
因此由于动态性能要求越来越高，多模式控制方法带来的动态问题，提出一种提高开关电源动态响应的控制方法。对减小电压过冲与欠压，减小动态回复时间有很好的效果，对提高电路的动态性能很有必要。
发明内容
为克服现有技术的局限和不足，本发明提出了一种提高开关电源动态响应的控制方法，可以限制输出电压的过冲与欠压在一定的范围内，并减小动态回复时间，提高动态性能，在多模式控制中不会引起系统的不稳定，使得电路的设计动态性能更优秀。
为了实现上述目的，本发明采用的技术方案是：
一种提高开关电源动态响应的控制方法，其特征在于：基于包括采样模块、动态控制模块、误差计算模块、PID模块、模式控制模块以及PWM模块构成的控制系统，该控制系统与受控的开关电源连接起来构成一个闭环；
采样模块包括采样电路和采样计算模块，采样电路通过开关电源输出分压得到输出电压的信息，采样计算模块根据采样电路的结果计算得到输出电压大小的信号Vo；
动态控制模块包括电压监测模块和斜率计算模块；电压监测模块接收采样模块输出的采样结果Vo并根据Vo的大小分别与设定的Vo上限值Vomax、Vo下限值Vomin以及参考电压Vref的大小关系，判断是否采用动态模式，其中Vomin＜Vref＜Vomax；动态模式是指当输出电压Vo变化很大时，通过输入大功率或小功率的方法使得输出电压Vo快速返回到稳定电压，动态模式包括恒定频率的轻载切重载LTH模式及恒定频率的重载切轻载HTL模式；
电压监测模块将模式选择结果mode_F输出到模式控制模块与斜率计算模块，若电压监测模块判断系统进入动态模式时，斜率计算模块计算电压变化斜率；若正常工作模式时，控制斜率计算模块的输出锁存不变；斜率计算模块在电压监测模块输出LTH模式时计算Vo的上升斜率；电压监测模块输出HTL模式时，计算Vo下降的斜率；采用正常工作模式时，斜率计算模块不计算斜率，斜率Kslope保持不变；斜率计算模块的结果Kslope输出给模式控制模块；
电压监测模块中包含三个比较器COMP1、COMP2和COMP3以及一个逻辑单元，比 较器COMP1的正端连接设定的Vo上限值Vomax，负端连接Vo；比较器COMP2的正端连接Vo，负端连接设定的参考电压Vref；比较器COMP3的正端连接Vo，负端连接设定的Vo下限值Vomin，逻辑单元单元根据三个比较器的结果，输出LTH模式、HTL模式及正常模式三种模式中的一种：
当Vo比下限电压Vomin小，逻辑单元输出动态模式中恒定频率的轻载切重载LTH模式，通过输入大功率使得输出快速上升到参考电压Vref后跳出该模式，进入正常模式，正常模式的起始状态由模式控制模块给定；
当Vo比上限电压Vomax大，逻辑单元输出动态模式中恒定频率的重载切轻载HTL模式，通过输入小功率使得输出快速下降到参考电压Vref后跳出该模式，进入正常模式，正常模式的起始状态由模式控制模块给定；
如果Vo变化不大，无需动态模式，通过正常的PI控制方法与模式控制实现环路控制称为正常工作模式；
当Vo介于Vomin与Vref之间，如果逻辑单元上周期输出为LTH模式，则本周期输出为LTH模式；若果逻辑单元上周期输出为HTL模式，本周期输出为正常模式；如果逻辑单元上周期输出为正常模式，则本周期输出为正常模式；当Vo介于Vref与Vomax之间，如果逻辑单元上周期输出为LTH模式，则本周期输出为正常模式；如果逻辑单元上周期输出为HTL模式，则本周期输出HTL模式；如果逻辑单元上周期输出为正常模式，则本周期输出为正常模式；
斜率计算模块的输入是采样结果Vo和电压监测模块的输出mode_F，当mode_F为LTH模式时，计算Vo的上升斜率Kup，采用N1个LTH模式开关周期电压变化等效代替，即Kup＝Vo(n)-Vo(n-N1)，Vo(n)为当前周期采样结果，Vo(n-N1)为N1个周期前的采样结果，Kup为输出斜率计算模块的结果Kslope的大小；当mode_F为HTL模式时，计算Vo的下降斜率Kdown，采用N2个HTL模式开关周期电压变化等效代替，即Kdown＝Vo(n-N2)-Vo(n)，Kdown为输出Kslope的大小；当mode_F为正常模式时，斜率计算模块不工作，输出结果Kslope通过锁存保持不变；
误差计算模块的输入是采样模块的输出Vo，根据计算参考电压Vref减去输出电压Vo的差，即为当前采样误差，记为e1，输出给PID模块；
模式控制模块的输入分别为电压监测模块的输出mode_F、斜率计算模块的输出Kslope以及PID模块的运算结果VPI；当电压监测模块输出mode_F为动态模式时，模式控制模块通过输出控制信号PI_ctrl关闭PID模块，控制PWM模块接收模式控制模块输 出的动态模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH/电流或DHTL/电流信息，PWM模块此时根据动态模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH/电流或DHTL/电流信息产生占空比波形；当模式控制模块在跳出动态模式进入正常工作模式的第一个开关周期，模式控制模块根据此时斜率计算模块的斜率大小Kslope得到对应的输出负载的大小，通过控制信号PI_ctrl，开启PID模块并在PID计算前将当前采样结果赋值VPI0，VPI0为负载变化后在稳定状态时负载对应的PID模块的输出值，赋值后PID模块根据误差模块的输出误差进行PID运算，PID运算结果VPI反馈给模式控制模块进行正常工作模式中的模式选择与控制；当模式控制模块在跳出动态模式进入正常工作模式的第二个开关周期以及以后，PI_ctrl开启PID模块进行运算，PID模块根据误差模块的输出误差进行PID运算，运算结果VPI反馈给模式控制模块进行正常工作模式中的模式选择与控制，在正常工作模式中，PWM模块接收PID输出的补偿结果VPI与模式控制模块给出的正常工作模式的控制模式，该控制模式记为mode_ctrl，通过计算得到开关周期与占空比/电流信息，PWM模块此时根据该开关周期与占空比信号产生占空比波形；
PID模块输入为误差计算模块输出的误差信号e1、模式控制模块输出的控制信号PI_ctrl以及赋值VPI0，动态模式时，PID模块关闭，动态模式切换到正常工作模式的第一个开关周期时，首先对PID模块运算赋初值VPI0，然后进PID运算，补偿计算结果VPI输出给模式控制模块和PWM模块，之后正常工作模式的每个周期进PID运算，补偿结果VPI输出给模式控制模块和PWM模块；
PWM模块的输入为模式控制模块输出的PI_ctrl控制信号、LTH与HTL模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH或DHTL、模式控制模块在正常工作模式时的控制模式结果mode_ctrl以及PID模块的补偿结果VPI；通过PID模块补偿结果VPI与模式控制模块给出的正常工作模式的控制模式mode_ctrl信号计算得到正常控制时开关周期与占空比的信息，得到周期与占空比/峰值电流信息后，通过驱动电路输出占空比波形，对开关电源功率管的栅极实现环路控制；然后再次对开关电源的输出电压进行采样，并重复上述过程进行循环控制开关电源功率管的开通和关断，以使系统更加稳定，从而获得更高的动态响应。
本发明的优点及显著效果：
1、本发明提出的动态控制方法，能够在输出电压超出上限电压时，通过小能量的重载切轻载模式使得输出快速稳定，在输出电压低于下限电压时，通过大能量的轻载切重载模式使得输出快速稳定，负载切换时输出电压的变化被限制在上限电压与下限电压之间， 电压变化大幅度减小，动态恢复时间大幅度减小。
2、本发明提出的动态控制方法在重载切轻载模式与轻载切重载模式中计算输出电压变化的斜率，并根据斜率与负载的一一对应单调性质的关系得到负载的大小，当跳出上面两种模式后，跳到对应负载点的工作状态，跳变后能量与负载稳态消耗相差不大，消除了后续的电压振荡，减小动态恢复时间。另外通过斜率来确定跳出后的负载大小，能够避免跳变后能量与负载稳态消耗相差较大引起的大的电压谐振，使得重载切轻载模式，轻载切重载模式与正常模式产生的振荡，电路更稳定。
3、本发明增加重载切轻载模式与轻载切重载模式两种工作模式，以及斜率判断工作点的方法对一般的多模式设计环路的稳定性不会产生影响。
4、本发明可以提高电路设计的灵活性，由于重载切轻载模式与轻载切重载模式的斜率与模式时间关系，模式时间可以代替电压斜率的功能，电压斜率与模式时间均可以适用于模拟设计与数字设计，使得应用控制更加广泛，提高电路动态响应。
5、本发明能适用于各类开关电源电路结构，具备通用性，可复用性和可移植性；
附图说明
图1a是本发明控制方法的系统结构框图；图1b是图1a中的电压监测模块结构框图；图1c是是图1a中的斜率计算模块结构框图；
图2是重载切轻载HLT模式的应用示意图；
图3是轻载切重载LTH模式的应用示意图；
图4a是具有本发明的多模式控制反激变换器的闭环电路结构图实施例；图4b是该反激系统在稳定状态时工作在正常工作模式时，开关频率与负载电流的关系。
图5是对图4的反激flyback电路在负载切换时多模式控制的动态响应的曲线，图5a为负载从700Ω切换到5Ω时，未采用本文的提高动态方法前的动态结果；图5b为负载从700Ω切换到5Ω时，采用了本文的提高动态方法后的动态结果；图5c为负载从5Ω切换到700Ω时，未采用本文的提高动态方法前的动态结果；图5d为负载从5Ω切换到700Ω时，采用了本文的提高动态方法后的动态结果；
图6是对图4的反激flyback电路，当控制方法跳出LTH模式时，图6a为初始工作状态固定为满载时的动态效果，图6b是以斜率Kup来确定初始工作状态的动态效果；
图7是对图4的反激flyback电路，当控制方法跳出HLT模式时，图7a为初始工作状态固定为待机时的动态效果，图7b是以斜率Kdown来确定初始工作状态的动态效果。
具体实施方式
参看图1，实线箭头是正常工作模式中控制环路使用的信号流程，虚线箭头与实线箭头是动态模式中控制环路中的信号流程。
本发明提高开关电源动态响应的控制方法，基于包括采样模块、动态控制模块、误差计算模块、PID模块、模式控制模块以及PWM模块构成的控制系统，该控制系统与受控的开关电源连接起来构成一个闭环；
采样模块中的采样电路对开关电源的输出电压进行采样，得到输出电压信息输入到采样计算模块，采样计算模块根据采样算法得到输出电压大小的信号Vo，将当前的采样电压Vo输入到动态控制模块与误差计算模块，误差计算模块计算当前的电压误差。
动态控制模块包括电压监测模块与斜率计算模块。电压监测模块根据采样结果Vo判断是否采用动态模式，所谓动态模式是当负载电压变化很大时，这里设定上限电压Vomax与下限电压Vomin，当Vo大于Vomax或Vo小于Vomin时，认为电压变化很大，需要通过输入大功率或小功率的方法使得输出电压快速返回到稳定电压，当输出电压比下限电压Vomin小，此时引入动态模式中恒定频率的轻载切重载模式(LTH)，通过输入大功率使得输出快速上升到参考电压Vref后跳出该模式，当输出电压比上限电压Vomax大，此时引入动态模式中恒定频率的重载切轻载模式(HTL)，通过输入小功率使得输出快速下降到参考电压Vref后跳出该模式，反之，如果输出电压突然变化但变化不大，无需动态模式时，通过正常的PI控制方法与模式控制实现环路控制称为正常工作模式；电压监测模块输出的模式结果(mode_F)输入到模式控制模块与斜率计算模块，若电压监测模块判断系统进入动态模式时，斜率计算模块计算电压变化斜率，若正常工作模式时，控制斜率计算模块的输出锁存不变。斜率计算模块在电压监测模块输出LTH模式时计算电压的上升斜率，输出HTL模式时，计算电压下降的斜率，采用正常工作模式时，不计算斜率，输出保持不变。斜率计算模块的结果Kslope输入到模式控制模块。
模式控制模块的输入分别为电压监测模块的模式输出(mode_F)，斜率计算模块的输出斜率Kslope以及PID模块的运算结果VPI。当电压监测模块输出mode_F为动态模式(LTH模式或HTL模式)时，该模块输出控制信号PI_ctrl关闭PID模块，控制PWM模块接收该模块输出的动态模式的开关周期Ts_LTH或Ts_HTL与占空比Ton_LTH或Ton_HTL(或电流)信息，PWM模块此时根据该两者信号产生占空比波形；当模式控制模块在跳出动态模式进入正常工作模式的第一个开关周期，模式控制模块根据此时的斜率计算模块的斜率大小Kslope得到对应的输出负载的大小，通过输出控制信号PI_ctrl，开启PID模块并在PID计算前将当前采样结果赋值VPI0，VPI0为负载变化后在稳定状态时负载对应的PID 模块的输出值，赋值后PID模块根据误差模块的输出误差进行PID运算，PID运算结果VPI反馈回模式控制模块进行正常工作模式中的模式选择与控制；当模式控制模块在跳出动态模式进入正常工作模式的第二个开关周期以及以后，输出控制信号PI_ctrl开启PID模块进行运算，PID模块根据误差模块的输出误差进行PID运算，运算结果VPI反馈回模式控制模块进行正常工作模式中的模式选择与控制，在正常工作模式中，PWM模块接收PID输出的补偿结果VPI与模式控制模块给出的正常工作模式选择的控制模式(mode_ctrl)通过计算得到开关周期与占空比(或电流)信息，PWM模块此时根据该两者信号产生占空比波形；
PID模块输入为误差计算模块输出的误差信号，模式控制模块输出的控制信号PI_ctrl与赋值VPI0。动态模式时，PI_ctrl控制PID模块关闭，动态模式切换到正常工作模式的第一个开关周期时，首先进行PID运算赋初值VPI0，然后进PID运算，补偿计算结果VPI输入模式控制模块与PWM模块，之后正常工作模式的每个周期进PID运算，补偿结果VPI输入模式控制模块与PWM模块。
PWM模块根据模式控制模块输出的控制信号PI_ctrl选择接受动态模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH或DHTL(或电流)信息或通过PID模块补偿结果VPI与模式控制模块给出的正常工作模式的模式信号mode_ctrl计算得到正常控制时开关周期与占空比的信息，得到周期与占空比(或峰值电流)信息后，通过驱动电路输出占空比波形，实现环路控制，通过动态控制模块，实现负载变化较大时，提高开关电源的动态响应；然后再次对开关电源的输出电压进行采样，并重复上述过程进行循环控制开关电源功率管的开通和关断，以使系统更加稳定，从而获得更高得动态响应。
采样模块包括采样电路，采样计算模块，采样电路通过输出分压得到输出电压的信息，采样计算模块根据采样电路的结果给出采样电路控制信号与输出电压Vo。这里的采样可以是直接采样或间接采样，采样结果可以是模拟量或数字量。
动态控制模块包括电压监测模块与斜率计算模块。
电压监测模块根据采样结果Vo判断是否采用动态模式，在电压监测模块中包含三个比较器以及一个逻辑单元判断是否采用动态模式，三个比较器分别判断采样电压Vo与下限电压Vomin，采样电压Vo与上限电压Vomax，采样电压Vo与参考电压Vref的大小关系，逻辑单元单元根据比较器结果输出模式选择结果，其输出结果mode_F为HTL模式(mode_LTH)，LTH模式(mode_HTL)，正常工作模式(mode_normal)三者之一，当Vo大于Vomax时，输出mode_F为mode_HTL，即启动HTL模式，当Vo小于Vomin时， 输出mode_F为mode_LTH，即启动LTH模式，当Vo介于Vomin与Vref之间，如果逻辑单元上周期为LTH模式，则本周期输出为LTH模式，如果上周期为HTL模式，则本周期输出为为正常工作模式，如果上周期为正常工作模式，则本周期输出为正常工作模式，当Vo介于Vref与Vomax之间，如果上周期为LTH模式，则本周期输出为正常工作模式，如果上周期为HTL模式，则本周期输出为HTL模式，如果上周期为正常工作模式，则本周期输出为正常工作模式。模式选择结果输入到动态模块中的斜率计算模块与模式控制模块。
斜率计算模块的输入是采样结果Vo与电压监测模块的输出模式mode_F，若输出为LTH模式时，计算Vo的上升斜率Kup，一般可以以N1个LTH模式开关周期电压变化等效代替即Kup＝Vo(n)-Vo(n-N1)，Vo(n)为当前周期采样结果，Vo(n-N1)为N1个周期前的采样结果，Kup为输出Kslope的大小，当电压监测模块的输出模式为HTL模式时，计算Vo的下降斜率Kdown，一般可以用N2个HTL模式开关周期电压变化等效代替即Kdown＝Vo(n-N2)-Vo(n)，Kdown为输出Kslope的大小，当电压监测模块的输出模式为正常工作模式时，该模块不工作，输出结果Kslope通过锁存保持不变。该模块的输出结果Kslope输入到模式控制模块。
误差计算模块输入是采样电路的输出Vo，根据计算参考电压Vref减去输出电压Vo的差，即为当前采样误差，记为e1，输入到PID模块。或与占空比或
模式控制模块的输入分别为电压监测模块的输出模式mode_F以及斜率计算模块的输出Kslope。当电压监测模块的输出模式(mode_F)为LTH模式(mode_LTH)时，该模块输出控制信号PI_ctrl，输入到PID模块与PWM模块，此时PI_ctrl关断PID模块并控制PWM信号接收该模块输出的LTH模式开关周期大小Ts_LTH与占空比DLTH(或电流)大小，记此时PI_ctrl为PI_off；当电压监测模块的输出模式(mode_F)为HTL模式(mode_HTL)时，该模块输出控制信号PI_ctrl，输入到PID模块与PWM模块，此时PI_ctrl关闭PID模块并控制PWM信号接收该模块输出的HTL模式开关周期大小Ts_HTL与占空比DHTL(或电流)大小，记此时PI_ctrl为为PI_off；当电压监测模块的输出模式(mode_F)为正常工作模式(mode_normal)，若上一个开关周期为LTH模式或HTL模式，该模块输出控制信号PI_ctrl，输入到PID模块与PWM模块，此时PI_ctrl记为PI_set，启动PID模块，先给PID模块运算结果赋值，赋值大小VPI0由mode_F与Kslope通过能量守恒计算得到负载后再根据正常工作模式计算得到，之后进行PID运算，控制PWM模块接收PI运算结果，并接收VPI根据PI计算结果进行正常工作模式的模式选择结果(mode_ctrl) 输入PID模块与PWM模块，若上一个开关周期电压监测模块的输出模式(mode_F)为正常工作模式(mode_normal)，该模块输出控制信号PI_ctrl，输入到PID模块与PWM模块，此时PI_ctrl记为PI_on，启动PID模块进行PID运算，控制PWM模块接收PID模块补偿结果VPI，并接收VPI根据VPI进行正常工作模式的控制，将正常工作模式的模式选择结果(mode_ctrl)输入到PID参数选择模块与PWM模块，
PID模块包括PID运算功能与PID参数选择功能，PID模块在模式控制模块输出的控制信号(PI_ctrl)与正常工作模式的模式选择结果(mode_ctrl)的控制下工作，PI_ctrl为PI_off时，PID模块关闭；PI_ctrl为PI_set时，VPI被模式控制模块输出的VPI0赋值后，根据正常工作模式的模式选择结果(mode_ctrl)选择PID运算参数，包括比例参数Kp，积分参数Ki，微分参数Kd进行PID运算，当PI_set为PI_on时，根据正常工作模式的模式选择结果(mode_ctrl)选择PID参数，包括比例参数Kp，积分参数Ki，微分参数Kd，进行PID运算，补偿结果VPI输入模式控制模块与PWM模块。
PWM模块的输入为模式控制模块输出的控制信号PI_ctrl，LTH与HTL模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH或DHTL，以及正常工作模式的模式选择结果(mode_ctrl)信号，PID模块的补偿结果VPI。当PI_ctrl为PI_off时，接收模式控制模块输出的LTH与HTL模式的开关周期与占空比(或峰值电流)，当PI_ctrl为PI_set或PI_on时，接收模式控制模块输出的正常工作模式的模式选择结果(mode_ctrl)与PID模块的补偿结果VPI，根据mode_ctrl的结果选择合理方法通过VPI计算得到正常模式的开关周期与占空比(或峰值电流)；得到周期与占空比(或峰值电流)信息后，得到占空比波形，PWM单元的输出连接驱动电路，驱动电路尽可能选择延迟时间小的电路，驱动电路的输出连接开关电源功率管的栅极。
参看图2，在轻载切重载时，从该示意图可以看到当输出电压低于Vomin时，采用LTH模式。若采用PID调节则如粗虚线所示，在输出电压下降到Vomin后电压任然会有所下降，动态恢复时间也很长。采用LTH模式，当输出电压低于Vomin时，立刻采用LTH模式，由于该模式的能量一般大于满载能量，输出电压立刻开始上升，不会再有所下降，在输出电压上升稳定值前，这是最快的动态方法，当输出电压与稳定电压相同时，可以通过斜率大小得到输出负载大小，使得跳出LTH模式的工作模式能量与负载功耗相近，去掉后续能量不吻合引入的谐振，如实线所示；可以看到若跳出LTH模式后，若工作状态从满载开始，其输入能量偏大，引入电压谐振，如细虚线所示。
参看图3，在重载切轻载时，从该示意图可以看到当输出电压大于Vomax时，采用 HTL模式。若采用PID调节则如粗虚线所示，在输出电压上升到Vomax后电压任然会有所上升，动态恢复时间也很长；采用HTL模式，当输出电压大于Vomax时，立刻采用HTL模式，由于该模式的输入功率一般小于于待机功率，输出电压立刻开始下降，不会再有所上升，在输出电压下降到稳定值前，这是最快的动态方法，当输出电压与稳定电压相同时，可以通过斜率大小得到输出负载大小，使得跳出HTL模式的工作模式能量与负载功耗相近，去掉后续能量不吻合引入的谐振，如实线所示；可以看到若跳出HTL模式后，若工作状态从待机开始，其输入能量偏低，引入电压谐振，如细虚线所示。
图4a为以反激电路作为对象的实施例。本发明使用的方法和系统也可用于其他类型的开关电源电路结构，此处以原边反馈的反激电路为例。反激变换器实例的输入为90～265V，输出为5V，电流最大为1A，电感大小为1.6mH，变压器匝比为104/6，输出恒压。变换器采用DCM的控制方法，通过多模式控制方法实现数字控制，下面给出已有电路的在不同负载下的工作模式，在该模式的基础上，增加本实例中优化动态性能的工作方法。
从轻载到重载的模式控制方法为DPFM-DPWM-PFM-PWM如图4b。下面分别定义多模式工作的方法。定义1A负载，为负载A，即为满载，开关频率fA为70kHz，电路具有较高的效率，0.7A负载为负载B，开关频率fB为70kHz，0.2A负载为负载C，开关频率fC为20kHz，0.05A负载为负载D，开关频率fD为20kHz，负载点的开关频率选择是根据系统效率要求而选择的。当负载介于AB之间，采用PWM模式，开关频率为70kHz；负载介于BC之间，采用PFM模式，原边峰值电流为0.255A；负载介于CD之间，采用DPWM模式，记为DPWM模式，开关频率为20kHz；负载小于负载D时，采用PWM模式，记为DPFM模式，原边峰值电流为0.151A。负载从轻到重的工作模式为DPFM-DPWM-PFM-PWM。这里待机时假负载700Ω，待机时电路工作在DPFM模式，原边峰值电流为0.151A，开关频率为3kHz；满载5Ω时，原边峰值电流为0.365A，开关频率为70kHz。
定义轻载切重载模式(LTH)，为了保证在任何条件下，当负载从轻载切到重载，输出能够很快上升到目标电压，LTH的输入功率需要尽可能的大，并且输入功率恒定，因此该模式是一种周期固定，原边峰值电流固定的控制方法。为了提高电压上升速度，需要加大该模式下输入功率，有两种方法，一是频率与70kHz的PWM模式相同，峰值电流尽可能取更大值，但需要保证系统需要工作在DCM模式下，并且有一定的时间裕量用于计算，这种条件需要在最小输入电压的条件下给定；二是在输入电压最低时，原边峰值电流取较大的值，一般大于等于满载的峰值电流，然后在满足DCM工作与计算裕量的要求 下，提高开关频率。本实例以第一种方法为例，取原边峰值电流为0.4A，开关周期为70kHz。定义重载切轻载模式(HTL)，为了保证在任何条件下，当负载从重载切到轻载，输出能够很快下降到目标电压，重载切轻载的输入功率需要尽可能的小，并且输入功率恒定，因此该模式是一种周期固定，原边峰值电流固定的控制方法。为了提高电压下降速度，需要减小该模式下输入功率，小于待机的功耗，一般有两种方法，一是原边电流与DPFM模式相同，开关频率尽可能的低，但需要保证系统从辅助绕组采样时，不会因为RCD钳位电压过低而使得辅助绕组波形变形，使得对输出电压的采样产生较大的误差，这种条件需要保证此时的RCD电路的钳位电压足够高；二是，原边峰值电流小于DPFM的峰值电流，同时尽可能降低开关频率，这种方法也需要满载RCD电路钳位电压足够高的要求，使得轻载能够准确采样。本实例重载切轻载模式以第一种方法为例，取原边峰值电流为0.151A，开关周期为2kHz。
根据方程
Figure PCTCN2016072693-appb-000001
原边电感Lp＝1.6mH，LTH模式的原边峰值电流为Ip_LTH＝0.4A，开关周期为TLTH＝14.3us，η为系统效率取0.8，Io(n)为输出负载电流。为了减小上升斜率的误差，由当前周期采样结果V(n)减去五个周期前的采样结果V(n-5)作为斜率的大小，可以得到当负载从轻载切到重载时，LTH被调用，输出负载及其对应工作状态与斜率的关系为表1，因此举例而言，当轻载切换到重载7Ω时，当输出电压达到5V，跳出LTH模式，进入PFM模式，起始的工作状态是周期350个时钟(57kHz)，原边峰值电流0.286A，这样输出不会引入大的纹波。输出电压通过数字采样，5V对应的数字量为583，Kup以该数字值来计算。
表1
Kup 负载 Mode Ts/clk Ip/A
0～3 5Ω PWM 286 0.363
4～5 6Ω PWM 286 0.286
6 7Ω PFM 350 0.286
7 10-12Ω PFM 513 0.286
8 12-15Ω PFM 602 0.286
9 15-20Ω PFM 961 0.286
10～ 20Ω～ DPWM 1000 0.231
根据方程
Figure PCTCN2016072693-appb-000002
HTL模式的原边峰值电流为Ip_HTL＝0.141A，开关周期为THTL＝500us，η为系统效率取0.6，Io(n)为输出负载电流。为了减小下降斜率的误差，由五个周期前的采样结果V(n-3)减去当前周期采样结果V(n)作为斜率的大小，可以得到当负载从重载切到轻载时，HTL被调用，输出负载及其对应工作状态与斜率的关系为表2，因此举例而言，当负载从重载切换到轻载500Ω时，当输出电压达到5V，跳出HTL模式，进入DPFM模式，起始的工作状态是周期4330个时钟(4.62kHz)，原边峰值电流0.151A，这样输出不会引入大的纹波。输出电压通过数字采样，5V对应的数字量为583，Kdown以该数字值来计算。
表2
Kdown 负载 Mode Ts/clk Ipeak/A
0～～1 500-700Ω DPFM 5650 0.151
2 400-500Ω DPFM 4330 0.151
3～4 200-400Ω DPFM 1690 0.151
5～6 120-200Ω DPWM 1000 0.151
7～ ～120Ω DPWM 1000 0.192
以上是该5V，1A的原边反馈反激电源的设计实例的具体参数。
图5为本发明对图4的反激flyback电路的一般多模式控制方法的负载切换时动态响应的曲线；以及采用了本文提高动态响应的技术的动态响应的曲线；此为本发明实施例；图5a为负载从700Ω切换到5Ω时，未采用本文的提高动态方法前的动态结果，图5b为负载从700Ω切换到5Ω时，本实例的动态结果。未采用前，输出电压欠压为1.3V，恢复时间为11.86ms，采用本技术后电压欠压为0.332V，恢复时间为0.932ms，动态性能大幅度提升。图5c为负载从5Ω切换到700Ω时，未采用本文的提高动态方法前的动态结果，图5d为负载从5Ω切换到700Ω时，未采用前，输出电压过压为0.584V，恢复时间为126.3ms，采用本技术后，输出电压过压为0.152V，恢复时间为43.4ms，动态性能大幅度提升。本实例的动态结果得到很大提升。
图6是对图4的反激flyback电路中跳出LTH模式时，工作状态固定为满载与以斜率 Kup来确定工作状态两者的对比；此为本发明实施例。可以看到当负载从700Ω切换到7Ω时，当系统输出达到5V，跳出LTH模式时，在图6a中，以满载的工作状态开始调整，此时输入功率大于负载功耗，输出电压会上升，引入电压振荡；在图6b中，跳出LTH模式时，kup为6，对应负载为7Ω左右，此时工作状态从PFM模式，周期350个时钟(57kHz)，原边峰值电流0.286A开始，不会引入电压振荡，此时输出电压可以认为已经稳定，去掉了后面的谐振电压，动态过程的恢复时间得到减小。
图7是对图4的反激flyback电路中跳出HLT模式时，工作状态固定为待机与工作状态以斜率Kdown来确定这两者的对比，此为本发明实施例。可以看到当负载从5Ω切换到100Ω时，当系统输出达到5V，跳出HTL模式时，在图7a中，以待机的工作状态开始调整，此时输入功率小于负载功耗，输出电压会下降，引入电压振荡；在图7b中，跳出HTL模式时，Kdown为5，对应负载为100Ω左右，此时工作状态从DPWM模式，周期1000个时钟(20kHz)，原边峰值电流0.151A开始，不会引入电压振荡，此时输出电压可以认为已经稳定，去掉了后面的谐振电压，动态过程的恢复时间得到减小。
从上面的实例中可以看出，采用本文的方法后，尤其对于多模式控制系统，动态性能得到了大幅度的提高。
以上内容是结合具体的优选实施方式对本发明所作的进一步详细说明，不能认定本发明的具体实施只局限于这些说明，在此描述的本发明可以有许多变化(斜率可以等效时间长度)，这种变化不能人为偏离本发明的精神和范围。因此，所有对本领域技术人员显而易见的改变，都包括在本权利要求书的涵盖范围之内。

Claims (1)

  1. 一种提高开关电源动态响应的控制方法，其特征在于：基于包括采样模块、动态控制模块、误差计算模块、PID模块、模式控制模块以及PWM模块构成的控制系统，该控制系统与受控的开关电源连接起来构成一个闭环；
    采样模块包括采样电路和采样计算模块，采样电路通过开关电源输出分压得到输出电压的信息，采样计算模块根据采样电路的结果计算得到输出电压大小的信号Vo；
    动态控制模块包括电压监测模块和斜率计算模块；电压监测模块接收采样模块输出的采样结果Vo并根据Vo的大小分别与设定的Vo上限值Vomax、Vo下限值Vomin以及参考电压Vref的大小关系，判断是否采用动态模式，其中Vomin＜Vref＜Vomax；动态模式是指当输出电压Vo变化很大时，通过输入大功率或小功率的方法使得输出电压Vo快速返回到稳定电压，动态模式包括恒定频率的轻载切重载LTH模式及恒定频率的重载切轻载HTL模式；
    电压监测模块将模式选择结果mode_F输出到模式控制模块与斜率计算模块，若电压监测模块判断系统进入动态模式时，斜率计算模块计算电压变化斜率；若正常工作模式时，控制斜率计算模块的输出锁存不变；斜率计算模块在电压监测模块输出LTH模式时计算Vo的上升斜率；电压监测模块输出HTL模式时，计算Vo下降的斜率；采用正常工作模式时，斜率计算模块不计算斜率，斜率Kslope保持不变；斜率计算模块的结果Kslope输出给模式控制模块；
    电压监测模块中包含三个比较器COMP1、COMP2和COMP3以及一个逻辑单元，比较器COMP1的正端连接设定的Vo上限值Vomax，负端连接Vo；比较器COMP2的正端连接Vo，负端连接设定的参考电压Vref；比较器COMP3的正端连接Vo，负端连接设定的Vo下限值Vomin，逻辑单元单元根据三个比较器的结果，输出LTH模式、HTL模式及正常模式三种模式中的一种：
    当Vo比下限电压Vomin小，逻辑单元输出动态模式中恒定频率的轻载切重载LTH模式，通过输入大功率使得输出快速上升到参考电压Vref后跳出该模式，进入正常模式，正常模式的起始状态由模式控制模块给定；
    当Vo比上限电压Vomax大，逻辑单元输出动态模式中恒定频率的重载切轻载HTL模式，通过输入小功率使得输出快速下降到参考电压Vref后跳出该模式，进入正常模式，正常模式的起始状态由模式控制模块给定；
    如果Vo变化不大，无需动态模式，通过正常的PI控制方法与模式控制实现环路控制称为正常工作模式；
    当Vo介于Vomin与Vref之间，如果逻辑单元上周期输出为LTH模式，则本周期输出为LTH模式；若果逻辑单元上周期输出为HTL模式，本周期输出为正常模式；如果逻辑单元上周期输出为正常模式，则本周期输出为正常模式；当Vo介于Vref与Vomax之间，如果逻辑单元上周期输出为LTH模式，则本周期输出为正常模式；如果逻辑单元上周期输出为HTL模式，则本周期输出HTL模式；如果逻辑单元上周期输出为正常模式，则本周期输出为正常模式；
    斜率计算模块的输入是采样结果Vo和电压监测模块的输出mode_F，当mode_F为LTH模式时，计算Vo的上升斜率Kup，采用N1个LTH模式开关周期电压变化等效代替，即Kup＝Vo(n)-Vo(n-N1)，Vo(n)为当前周期采样结果，Vo(n-N1)为N1个周期前的采样结果，Kup为输出斜率计算模块的结果Kslope的大小；当mode_F为HTL模式时，计算Vo的下降斜率Kdown，采用N2个HTL模式开关周期电压变化等效代替，即Kdown＝Vo(n-N2)-Vo(n)，Kdown为输出Kslope的大小；当mode_F为正常模式时，斜率计算模块不工作，输出结果Kslope通过锁存保持不变；
    误差计算模块的输入是采样模块的输出Vo，根据计算参考电压Vref减去输出电压Vo的差，即为当前采样误差，记为e1，输出给PID模块；
    模式控制模块的输入分别为电压监测模块的输出mode_F、斜率计算模块的输出Kslope以及PID模块的运算结果VPI；当电压监测模块输出mode_F为动态模式时，模式控制模块通过输出控制信号PI_ctrl关闭PID模块，控制PWM模块接收模式控制模块输出的动态模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH/电流或DHTL/电流信息，PWM模块此时根据动态模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH/电流或DHTL/电流信息产生占空比波形；当模式控制模块在跳出动态模式进入正常工作模式的第一个开关周期，模式控制模块根据此时斜率计算模块的斜率大小Kslope得到对应的输出负载的大小，通过控制信号PI_ctrl，开启PID模块并在PID计算前将当前采样结果赋值VPI0，VPI0为负载变化后在稳定状态时负载对应的PID模块的输出值，赋值后PID模块根据误差模块的输出误差进行PID运算，PID运算结果VPI反馈给模式控制模块进行正常工作模式中的模式选择与控制；当模式控制模块在跳出动态模式进入正常工作模式的第二个开关周期以及以后，PI_ctrl开启PID模块进行运算，PID模块根据误差模块的输出误差进行PID运算，运算结果VPI反馈给模式控制模块进行正常工作模式中的模式选择与控制，在正常工作模式中，PWM模块接收PID输出的补偿结果VPI与模式控制模块给出的正常工作模式的控制模式，该控制模式记为mode_ctrl，通过计算得到开关周期与占空比/电流信息，PWM 模块此时根据该开关周期与占空比信号产生占空比波形；
    PID模块输入为误差计算模块输出的误差信号e1、模式控制模块输出的控制信号PI_ctrl以及赋值VPI0，动态模式时，PID模块关闭，动态模式切换到正常工作模式的第一个开关周期时，首先对PID模块运算赋初值VPI0，然后进PID运算，补偿计算结果VPI输出给模式控制模块和PWM模块，之后正常工作模式的每个周期进PID运算，补偿结果VPI输出给模式控制模块和PWM模块；
    PWM模块的输入为模式控制模块输出的PI_ctrl控制信号、LTH与HTL模式的开关周期Ts_LTH或Ts_HTL与占空比DLTH或DHTL、模式控制模块在正常工作模式时的控制模式结果mode_ctrl以及PID模块的补偿结果VPI；通过PID模块补偿结果VPI与模式控制模块给出的正常工作模式的控制模式mode_ctrl信号计算得到正常控制时开关周期与占空比的信息，得到周期与占空比/峰值电流信息后，通过驱动电路输出占空比波形，对开关电源功率管的栅极实现环路控制；然后再次对开关电源的输出电压进行采样，并重复上述过程进行循环控制开关电源功率管的开通和关断，以使系统更加稳定，从而获得更高的动态响应。
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