CN112260524B - Digital power supply and synchronous rectification control method thereof - Google Patents

Digital power supply and synchronous rectification control method thereof Download PDF

Info

Publication number
CN112260524B
CN112260524B CN202011061909.XA CN202011061909A CN112260524B CN 112260524 B CN112260524 B CN 112260524B CN 202011061909 A CN202011061909 A CN 202011061909A CN 112260524 B CN112260524 B CN 112260524B
Authority
CN
China
Prior art keywords
time
current
turn
rectifier tube
power supply
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202011061909.XA
Other languages
Chinese (zh)
Other versions
CN112260524A (en
Inventor
夏生柱
师磊
郑许峰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leihua Electronic Technology Research Institute Aviation Industry Corp of China
Original Assignee
Leihua Electronic Technology Research Institute Aviation Industry Corp of China
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Leihua Electronic Technology Research Institute Aviation Industry Corp of China filed Critical Leihua Electronic Technology Research Institute Aviation Industry Corp of China
Priority to CN202011061909.XA priority Critical patent/CN112260524B/en
Publication of CN112260524A publication Critical patent/CN112260524A/en
Application granted granted Critical
Publication of CN112260524B publication Critical patent/CN112260524B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal 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
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal 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
    • 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
    • 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
    • H02M1/083—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the ignition at the zero crossing of the voltage or the current
    • 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
    • H02M1/0012—Control circuits using digital or numerical techniques
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Rectifiers (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application provides a synchronous rectification control method of a digital power supply, which comprises the steps of sampling currents before and after a rectifier tube is switched on/off once respectively, analyzing the currents twice before and after, if the currents twice are both 0 or negative, judging that the switching-on is too early, and adjusting the switching-on time of the rectifier tube in the next period to enable the switching-on time to be shifted backwards; if the voltage is 0 or negative before the switch-on and positive after the switch-on, the switch-on time is considered to be right, and the switch-on time of the rectifier tube in the next period is not adjusted; if the front and the back are positive, the switching-on time is considered to be too late, and the next switching period leads the switching-on time to move forward. After many times of correction, the turn-on time of the synchronous rectification rectifier tube can be converged to an ideal condition. The synchronous rectification method of the digital power supply can solve the problems that a rectification/follow current rectifier tube cannot be accurately controlled to be switched on when the current rises to the positive time, switched off when the current drops to zero and cannot adapt to load change in the prior art, so that the efficiency of the power supply converter is further improved and the cost is reduced.

Description

Digital power supply and synchronous rectification control method thereof
Technical Field
The application belongs to the technical field of digital power supplies, and particularly relates to a digital power supply and a synchronous rectification control method thereof.
Background
With the development of science and technology, switching power supplies are developed in the directions of high power density, high reliability and high efficiency. In an output converter of a high-current switching power supply, the power consumption of a rectifying/freewheeling diode accounts for 50-60% of the total power consumption of the converter. The MOSFET with low on-resistance replaces the conventional Schottky diode, so that the power consumption of the rectifying part can be greatly reduced, and the efficiency and the power density of the converter are improved. However, for discontinuous mode rectifier/freewheel MOSFET current, since the zero crossing of the current varies with the load, it is necessary to sense the current to accurately control the MOSFET to turn on when the current rises from zero to the forward direction and to turn off when the current falls to zero.
The current-mode self-driven synchronous rectification graph circuit collects current in a detection loop through an ADC (analog-digital converter, not shown), and turns on a MOSFET when a forward current is detected and turns off the MOSFET when the current drops to zero.
However, because a digital chip in the digital power supply needs time when acquiring and converting through an ADC (analog to digital converter), and there are turn-on and turn-off delays, the turn-on delay can cause that an MOSFET is not turned on when the current is in the forward direction, and follow current flows through a body diode of the MOSFET, so that the efficiency is reduced; and the turn-off delay can cause that the MOSFET is not turned off when the current is zero, the current can be a negative value at this time, the negative current can cause the output energy to be recharged to the primary, the efficiency is reduced, and the converter can be damaged under severe conditions.
In order to solve the above problem, the conventional control method sets a constant value, and turns on/off the MOSFET only when the current rises/falls to a certain value, so that the current is positive when the effective turn-on time of the MOSFET is ensured, but partial efficiency is sacrificed. In addition, the method needs to set the fixed value to be larger when the current slope is particularly steep, and can set the fixed value to be smaller when the current slope is more gentle, so that the method cannot cope with the situation that the load change is larger.
Disclosure of Invention
It is an object of the present application to provide a digital power supply and a synchronous rectification control method thereof to solve or mitigate at least one of the problems of the background art.
In one aspect, the technical solution provided by the present application is: a method for controlling synchronous rectification of a digital power supply, the method comprising:
determining the turn-on time t of the current period of the rectifier tube0And a turn-off time t1；
Constructing an offset time t to make the turn-on time of the rectifier tube be t0The current at + -t is i0-And i0+And the closing time of the rectifier tube is t1The current at + -t is i1-And i1+；
When the current i0-、i0+When the current is zero or negative, the turn-on time of the rectifier tube is judged to be too early, and the turn-on time t of the next period of the rectifier tube is adjusted2Make the turn-on time t2Backward shifting to delay turning on the rectifier tube; when the current i0-Is zero or negative and the current i0+If the current value is positive, judging that the turn-on time of the rectifier tube is proper, and not adjusting the turn-on time t of the next period of the rectifier tube2(ii) a When the current i0-、i0+When the current is positive, judging that the turn-on time of the rectifier tube is too late, and adjusting the turn-on time t of the next period of the rectifier tube2’Make the turn-on time t2Moving forward to open the rectifier tube in advance;
when the current i1-、i1+When the current is positive, the turn-off time of the rectifier tube is judged to be too early, and the turn-off of the rectifier tube in the next period is adjustedTime t3Make the turn-off time t3Backward shifting to delay the turn-off of the rectifier tube; when the current i1-Is positive and current i1+When the current value is zero or negative, judging that the turn-off time of the rectifier tube is proper, and not adjusting the turn-off time t of the next period of the rectifier tube3(ii) a When the current i1-、i1+When the current is zero or negative, judging that the turn-off time of the rectifier tube is too late, and adjusting the turn-off time t of the next period of the rectifier tube3Make the turn-off time t3The rectifier is turned off in advance.
Further, the offset time t is determined according to the sampling rate of the digital power supply.
In another aspect, the present application provides a digital power supply, which implements synchronous rectification control by using the digital power supply synchronous rectification control method as described in any one of the above.
The synchronous rectification method of the digital power supply can solve the problems that in the prior art, the rectification/follow current MOSFET cannot be accurately controlled to be switched on when the current rises to be positive, and switched off when the current drops to zero and cannot adapt to load change, so that the efficiency of the power supply converter is further improved and the cost is reduced.
Drawings
In order to more clearly illustrate the technical solutions provided by the present application, the following briefly introduces the accompanying drawings. It is to be expressly understood that the drawings described below are only illustrative of some embodiments of the invention.
Fig. 1 is a diagram of a conventional full-wave rectifier circuit.
Fig. 2 is a current waveform of the on/off full-wave rectifying circuit in an ideal state.
Fig. 3 is a current waveform when the rectifier is turned on too early or turned off too late.
Fig. 4 is a current waveform when the rectifier is turned on late or turned off early.
Detailed Description
In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application.
Fig. 1 shows a conventional full-wave rectification circuit, which is composed of a transformer T, a rectifier SR1, a rectifier SR2, an inductor L, a capacitor C, and a load R. FIG. 2 shows a current waveform i of an ideal ON/OFF full-wave rectifying circuitD1For the current waveform i flowing through the rectifier SR1D2Is the current waveform flowing through freewheeling tube SR 2. With iD1For example, the MOSFET is turned on at time t1 when the current rises from zero, and turned off at time t4 when the current drops to zero, whereby the current in the ideal state can be obtained. However, as stated in the background, there is a time delay in the opening of the rectifier due to the digital chip processing switching in the digital power supply. Fig. 3 shows the current waveform when the rectifier is turned on too early or turned off too late, wherein the current is reversed as shown in the X region, and energy is returned to the primary of the transformer, thereby reducing the efficiency of the power supply. Fig. 4 shows the current waveform when the rectifier is turned on late or turned off early, wherein as shown in the Y region, there is a portion of time when the rectifier is not being used effectively and current flows through the freewheeling diode, which also reduces power efficiency.
In order to solve the problems that the prior art can not accurately control the rectification/follow current MOSFET to be switched on when the current rises to be positive time, and switched off when the current drops to zero and can not adapt to the change of the load, thereby further improving the efficiency of the power supply converter and reducing the cost, the application provides a digital power supply and a synchronous rectification control method thereof.
Firstly, the synchronous rectification control method of the digital power supply provided by the application analyzes the current before and after the MOSFET is switched on/off by sampling the current once respectively, if the current of the two times is 0 or negative, the switching-on is considered to be too early, the switching-on time of the rectifier tube is adjusted in the next period, and the switching-on time is shifted backwards; if the voltage is 0 or negative before the switch-on and positive after the switch-on, the switch-on time is considered to be right, and the switch-on time of the rectifier tube in the next period is not adjusted; if the front and the back are positive, the switching-on time is considered to be too late, and the next switching period leads the switching-on time to move forward. After multiple corrections, the on-time of the synchronous rectifier MOSFET can be made to converge to an ideal condition. The same applies to the moment of switching off.
For example, in an embodiment, when the initial on/off time is a fixed proportion of the switching period, adjusting the on and off times by setting the offset time includes:
the method comprises the following steps: firstly, setting the initial time of switching on/off of a rectification/freewheeling MOSFET in a digital power supply, and in a switching period T, switching on a rectifier SR1 when the T is 15 percent, and switching off a rectifier SR1 when the T is 35 percent; the rectifier SR2 is turned on at 65% T, and the rectifier SR2 is turned off at 85% T.
Step two: the bias time T of one current sample is set, the current of SR1 is collected at 15% T +/-T and 35% T +/-T, and the current of SR2 is collected at 65% T +/-T and 85% T +/-T.
The on/off current waveform in the ideal state in fig. 2 is described with reference to the above time, where 15% T is time T1, 35% T is time T4, 65% T is time T7, and 85% T is time T10.
At this moment, the following situations can occur when the rectifier tube is switched on:
1) if the currents i0 and i2 are zero or negative, the MOSFET turn-on time can be considered to be too early;
2) the current i0 is zero or negative, while the current i2 is positive, the turn-on time is considered to be right;
3) if both currents i0 and i2 are positive, the on time is considered too late.
There are also three cases when the rectifier is off:
1: the currents i3, i5 are both positive, and the turn-off time is considered too early;
2: the current i3 is positive while the circuit i5 is 0 or negative, when the off-time is considered to be just;
3: the currents i3, i5 are both 0 or negative, and the turn-off time is considered too late.
Step three: in the interrupt routine of each switching cycle, it is determined whether the on/off is too early or too late. If the on/off is too early, then the on/off time is shifted backwards; if the on/off is too late, the on/off time is advanced. The on/off time is updated in the next switching cycle.
For example, if the on time t1 is too early, the on time is shifted backward, even if the time t1 shifts toward the time t 2. Similarly, when the on time t7 is too late, it is moved forward even if the time t7 is shifted toward the time t 6.
After a number of updates, the ideal on/off condition can be converged.
Finally, the application also provides a digital power supply which is realized by adopting the synchronous rectification control method.
Compared with the prior art, the power converter has the advantages that the efficiency of the power converter can be improved obviously on the basis of not increasing any hardware cost, the power density of the power converter is improved, the power converter is applicable to various load conditions, each load condition does not need to be dealt with, the cost is reduced, and the power converter can be applied to the fields of high power and large current.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (3)

1. A synchronous rectification control method for a digital power supply, the method comprising:
determining the turn-on time t of the current period of the rectifier tube0And a turn-off time t1；
Constructing an offset time t to make the turn-on time of the rectifier tube be t0The current at + -t is i0-And i0+And the closing time of the rectifier tube is t1The current at + -t is i1-And i1+；
When the current i is0-、i0+When the current is zero or negative, the turn-on time of the rectifier tube is judged to be too early, and the turn-on time t of the next period of the rectifier tube is adjusted2Make the turn-on time t2Backward shifting to delay turning on the rectifier tube; when it is at homeThe current i0-Is zero or negative and the current i0+If the current value is positive, judging that the turn-on time of the rectifier tube is proper, and not adjusting the turn-on time t of the next period of the rectifier tube2(ii) a When the current i0-、i0+When the current is positive, judging that the turn-on time of the rectifier tube is too late, and adjusting the turn-on time t of the next period of the rectifier tube2Make the turn-on time t0’Moving forward to open the rectifier tube in advance;
when the current i1-、i1+When the current is positive, the turn-off time of the rectifier tube is judged to be too early, and the turn-off time t of the next period of the rectifier tube is adjusted3Make the turn-off time t3Backward shifting to delay the turn-off of the rectifier tube; when the current i1-Is positive and current i1+When the current value is zero or negative, judging that the turn-off time of the rectifier tube is proper, and not adjusting the turn-off time t of the next period of the rectifier tube3(ii) a When the current i1-、i1+When the current is zero or negative, judging that the turn-off time of the rectifier tube is too late, and adjusting the turn-off time t of the next period of the rectifier tube3Make the turn-off time t3The rectifier is turned off in advance.
2. The digital power supply synchronous rectification control method of claim 1, wherein the offset time t is determined according to a rate of digital power supply sampling.
3. A digital power supply, characterized in that the digital power supply adopts the digital power supply synchronous rectification control method as claimed in any one of claims 1 or 2 to realize synchronous rectification control.
CN202011061909.XA 2020-09-30 2020-09-30 Digital power supply and synchronous rectification control method thereof Active CN112260524B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011061909.XA CN112260524B (en) 2020-09-30 2020-09-30 Digital power supply and synchronous rectification control method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011061909.XA CN112260524B (en) 2020-09-30 2020-09-30 Digital power supply and synchronous rectification control method thereof

Publications (2)

Publication Number Publication Date
CN112260524A CN112260524A (en) 2021-01-22
CN112260524B true CN112260524B (en) 2022-05-17

Family

ID=74234759

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011061909.XA Active CN112260524B (en) 2020-09-30 2020-09-30 Digital power supply and synchronous rectification control method thereof

Country Status (1)

Country Link
CN (1) CN112260524B (en)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107425728B (en) * 2017-02-28 2019-03-29 东南大学 A kind of digital optimal control method and its system of the synchronous rectification of LLC full-bridge converter
CN109194131B (en) * 2018-06-30 2020-04-14 东南大学 Self-adaptive synchronous rectification control system and control method of time division multiplexing hardware
CN108923625B (en) * 2018-07-23 2021-08-24 张正根 Synchronous rectifier control method and circuit

Also Published As

Publication number Publication date
CN112260524A (en) 2021-01-22

Similar Documents

Publication Publication Date Title
CN109995228B (en) Dead time automatic optimization system under primary side feedback flyback power supply CCM mode
CN109067181B (en) The adaptive synchronous commutating control system and control method of active clamp flyback converter
CN103326581B (en) LLC resonant converter, control circuit and driving method
US20060012348A1 (en) Coupled inductor DC/DC converter
US20190068068A1 (en) Resonant power converter and frequency tracking method for resonant power converter
US20200366211A1 (en) Control method of power conversion circuit, and related power conversion circuit
CN108418435B (en) Synchronous rectification flyback DC-DC power supply conversion device
AU2010319195A1 (en) Switching power supply circuit
JP6341247B2 (en) DC / DC converter
TWI697183B (en) Totem-pole bridgeless power factor corrector and power factor correction method
CN112087146B (en) Control method and circuit of asymmetric half-bridge flyback converter
CN113346750B (en) Soft-on Guan Tongxiang buck-boost converter based on coupling inductance and control method
CN112260524B (en) Digital power supply and synchronous rectification control method thereof
US20240195301A1 (en) Systems and methods for automatic determination of state of switches in power converters
WO2020007108A1 (en) Switching converter
Zhu et al. Adaptive Tuning Method for ZVS Control in GaN-based MHz CRM Totem-Pole PFC Rectifier
JP3755815B2 (en) Switching power supply
CN112152453B (en) Detection circuit, switching type voltage stabilizer with detection circuit and control method of switching type voltage stabilizer
CN113783402A (en) Self-adaptive control circuit and control method
CN112910259B (en) LLC conversion power supply, controller thereof and switching frequency tracking and adjusting method
JP3611794B2 (en) DC-DC converter circuit
CN211429196U (en) Synchronous rectifier control circuit and flyback voltage conversion circuit thereof
CN211791286U (en) Synchronous rectifier control circuit and flyback voltage conversion circuit
JP6645708B1 (en) Power converter
CN109962623B (en) Current type half-bridge DC converter control method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant