CN116633142A - Control method and control system of switching power supply - Google Patents
Control method and control system of switching power supply Download PDFInfo
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- CN116633142A CN116633142A CN202310048495.4A CN202310048495A CN116633142A CN 116633142 A CN116633142 A CN 116633142A CN 202310048495 A CN202310048495 A CN 202310048495A CN 116633142 A CN116633142 A CN 116633142A
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000005070 sampling Methods 0.000 claims abstract description 22
- 238000012545 processing Methods 0.000 claims description 6
- 230000001360 synchronised effect Effects 0.000 abstract description 3
- 208000031361 Hiccup Diseases 0.000 description 13
- 230000001276 controlling effect Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 4
- 238000012795 verification Methods 0.000 description 4
- 230000004044 response Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
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- 238000006467 substitution reaction Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—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
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- 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
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The application discloses a control method and a control system of a switching power supply, wherein the control method comprises the following steps: sampling the load current of the switching power supply in real time to obtain an output current sampling value signal; comparing the sampling value with a constant current threshold value, and if the sampling value of the output current is larger than the constant current threshold value, entering a constant current control mode by the system; and under the constant-current control mode, performing constant-current loop feedback loop operation and limiting the maximum output value of the constant-current loop control quantity so as to achieve the purpose of limiting the maximum output power of the system. The control method and the control system of the switching power supply have higher practicability and reliability, can realize accurate output current control, can effectively limit the output power of the converter when the output current is overlarge, avoid overstress and overheat damage risks of switching devices, and effectively improve the reliability of the system; meanwhile, synchronous startup of each switching power supply in the parallel operation capacity expansion system is guaranteed, and an implementation thought is provided for parallel operation capacity expansion application of the switching power supplies.
Description
Technical Field
The application belongs to the technical field of power electronics, and particularly relates to a control method and a control system of a switching power supply.
Background
At present, a switching power supply is a mainstream power supply in the market, and along with continuous updating and rapid development of a switching power supply technology and development of miniaturization, high frequency and high reliability of a semiconductor device, the high frequency switching power supply is involved in a plurality of industries, and the requirements of the industry on the switching power supply are more severe. Besides the performance requirements of high power, small volume, high efficiency and the like, more requirements are also put forward on the aspects of parallel operation capacity expansion, reliability and the like.
In the design of a switching power supply, short-circuit protection is an indispensable function, and common control methods such as short-circuit shutdown, short-circuit hiccup, short-circuit constant current and the like are adopted. The short-circuit turn-off protection is to directly turn off the output when detecting the output short circuit, and the mode generally requires the power supply system to be started first to load, because when the load is electrified, larger current can be generated at the moment of starting, the system can be considered to be in a short circuit state to stop starting, and meanwhile, the load carrying capacity of the switching power supply is reduced; short circuit hiccup protection, namely when short circuit is output, the system sequentially and repeatedly works in a sleep stage and a reset stage, and after short circuit fault elimination, the switching power supply resumes normal operation, which is the most common method for short circuit protection. Although the technical scheme plays a role in short circuit protection to a certain extent, the control mode of short circuit direct shutdown hiccup makes the switching power supply system difficult to realize parallel operation expansion and limits the application of the switching power supply. The short-circuit constant-current protection is to limit the output current when the output short circuit is detected, so that the output current works in a constant-current output state; the method provides a good solution for the parallel operation capacity expansion application of the switching power supply; however, the mode can generate larger short-circuit loss, thereby causing energy waste, and also causing the switch power supply to generate larger temperature rise, and serious potential safety hazard exists.
Therefore, aiming at the application situation of the switching power supply with the parallel operation capacity expansion requirement, when a short circuit fault occurs, the protection mode of 'constant current plus hiccup' is adopted, and the reliability of the system can be effectively improved.
Constant current protection is an accurate power control mode, generally uses a sampling resistor or a current transformer to detect the change of current, converts a current sampling signal into a voltage signal, performs differential comparison with a reference level, and obtains a feedback control signal of a constant current loop through operational amplifier proportional integration; or the sampling signal is directly sent to the controller, and the feedback control signal of the constant current loop is obtained by digital PID operation; further control the driving pulse of the power switch tube of the switch power supply to realize the accurate control of adjusting the output current.
When the output end of the switching power supply is short-circuited, the current is rapidly increased to trigger constant current protection, the feedback control of the constant current loop is enabled, the driving pulse width of the control converter is limited, and the output power of the system is greatly reduced. However, in practical application, due to factors such as sampling delay, loop bandwidth and the like, the response speed of constant current loop control is limited, and the damage risk caused by excessive instantaneous power still occurs in the system at the moment of short circuit.
Fig. 1 is a system waveform of a switching power supply at a short circuit moment in a conventional constant current protection mode, including: the power switch tube driving signal waveform 100, the output current waveform 200 and the power switch tube voltage waveform 300 of the bridge arm in the switch power supply can be seen that the output current rises rapidly at the moment of short circuit, the system enters the constant current loop at the moment of rising of the output current, but the system does not execute constant current feedback control in time due to slower regulating speed of the constant current loop, the output power continues to increase, and higher requirements are put forward on the current stress of the rectifying part device in the switch power supply. For a resonant converter in a switching power supply, the transient short-circuit output power surge causes the system working state to enter a capacitive region, the voltage stress of a power switching tube rises, and the phenomenon of overstress damage occurs.
Similarly, for other types of switching power supplies, voltage and current stress of the power tube can be threatened by sudden increase of output power caused by untimely short-circuit instant constant current control.
Disclosure of Invention
In order to overcome the defects of the prior art, the application aims to provide a control method and a control system of a switching power supply, so as to solve the problems of excessive instantaneous power and constant current protection failure caused by untimely response of a constant current loop.
In order to achieve the above purpose, the application adopts the following technical scheme: a control method of a switching power supply, comprising:
the voltage ring controls the switching power supply to output constant voltage through sampling the output voltage signal; the constant current loop controls the switching power supply to output constant current through sampling the output current signal; the voltage ring and the constant current ring can be realized through feedback loop operation;
determining the working mode of the switching power supply by judging the relation between the output voltage and the output current signals:
when the output voltage is larger than a set constant voltage threshold, the switching power supply works in a constant voltage control mode, and the voltage loop feedback operation unit acts to obtain voltage loop feedback control quantity information;
when the output voltage signal is smaller than a set constant voltage threshold value, the output current is further judged, and when the output current is detected to be larger than the set constant current threshold value, the switching power supply works in a constant current control mode, and at the moment, the constant current loop feedback operation unit acts to obtain constant current loop feedback control quantity information; otherwise, maintaining the control mode of the last state;
in the constant-current control mode, the maximum output power of the switching power supply is limited by limiting the maximum output value of the constant-current loop control quantity besides the conventional constant-current loop feedback operation, and the specific is that:
in the constant current control mode, the switching power supply executes constant current loop feedback operation to further judge the constant current loop feedback control quantity information; if the information of the constant-current loop feedback control quantity is smaller than the minimum threshold value of the constant-current loop control quantity, limiting the maximum output value of the constant-current loop to be the minimum threshold value of the constant-current loop control quantity; otherwise, the maximum output value of the limiting constant current ring is the set limiting control amount.
In one implementation, the setting of the minimum threshold of the constant current loop control amount can satisfy the gain requirement of the switching power supply in the constant current state, and the gain requirement of the switching power supply in the constant current state is determined by the topology characteristics of the specific converter of the switching power supply.
In one implementation, the set limit control amount may be equal to k times the normal constant current loop output control amount, where k < 1; the set limit control amount may also be equal to a fixed clipping value that varies with the input voltage, which may be measured from the power characteristics of the converter itself.
In one implementation, final voltage loop feedback control quantity information is obtained through judgment of a constant voltage control mode and loop operation; and obtaining the obtained constant current loop feedback control quantity information through judgment of the constant current control mode and loop operation.
In one implementation, when the switching power supply works in a constant voltage control mode, the voltage loop feedback control quantity information is converted into a driving signal for controlling a power switch tube of the switching power supply; when the switching power supply works in a constant-current control mode, the constant-current loop feedback control quantity information is converted into a driving signal for controlling a power switch tube of the switching power supply.
In one implementation, the constant current threshold may be set according to different application requirements of the switching power supply, and is typically set to 1.2 times the rated load current.
A control system for a switching power supply, comprising:
the voltage feedback unit is used for controlling the switching power supply to output constant voltage by sampling an output voltage signal of the switching power supply to perform constant voltage loop feedback operation;
the constant current feedback unit is used for controlling the switching power supply to output constant current by sampling an output current signal of the switching power supply to perform constant current loop feedback operation;
the control quantity operation unit is used for controlling the switching power supply to work in a constant voltage control mode or a constant current control mode according to the output voltage signal and the output current signal; when the switching power supply works in a constant voltage control mode, executing voltage loop operation processing to acquire voltage loop feedback control quantity information; when the switching power supply works in the constant current control mode, constant current loop operation processing is executed, and constant current loop feedback control quantity information is obtained;
the PWM pulse modulation unit is used for converting the feedback control quantity information of the voltage loop into a driving signal for controlling a power switch tube of the switching power supply when the switching power supply works in a constant voltage control mode; and the power switch tube is used for converting the information of the feedback control quantity of the constant current loop into a driving signal for controlling the power switch tube of the switching power supply when the switching power supply works in the constant current control mode.
Aiming at the switching power supply for parallel operation capacity expansion application, when the switching power supply has the fault conditions of overload, short circuit, over temperature and the like, in order to avoid the serious problems of energy waste and heating caused by long-time constant current operation of the switching power supply, a fault treatment mode of 'firstly carrying out constant current protection and then carrying out hiccup protection' can be adopted so as to improve the reliability of the switching power supply.
The fault processing mode of 'first constant current protection and then hiccup protection' is carried out, and the specific constant current protection is the control method of the switching power supply provided by the application; when the set constant current protection time is reached, the switching power supply is controlled to turn off the driving signal, the switching power supply enters a hiccup protection mode, and after the hiccup rest time is reached, the switching power supply tries to restart; if the fault continuously exists, the switching power supply is in a repeated protection mode of constant current and hiccup; and when the fault is eliminated, the switching power supply resumes normal operation.
Compared with the prior art, the application has the following beneficial effects:
1) Accurate output current control can be realized, and the current control precision is high;
2) When the output current is overlarge, the output power of the converter can be effectively limited, and the problem of high short-circuit power consumption of a high-power switching power supply is solved; meanwhile, overstress and overheat damage of the switching device are prevented, and the reliability of the switching power supply is effectively improved;
3) The synchronous start of each switching power supply in the parallel operation capacity expansion switching power supply is ensured, and an implementation thought is provided for parallel operation capacity expansion application of the switching power supply.
Drawings
FIG. 1 is a system waveform of a resonant converter switching power supply at a short circuit instant in a conventional protection mode;
FIG. 2 is a schematic block diagram of a switching power supply to which the control method according to the embodiment of the present application is applied;
FIG. 3 is a flow chart showing the implementation of constant voltage or constant current control mode selection in an embodiment of the present application;
FIG. 4 is a flowchart of a control method according to an embodiment of the present application;
FIG. 5 is a schematic block diagram of the execution of a constant voltage or constant current control mode in an embodiment of the present application;
FIG. 6 is an experimental waveform based on resonant converter verification for a conventional control method;
fig. 7 is an experimental waveform of the control method according to the present application based on the verification of the resonant converter.
Detailed Description
In order to ensure that the technical scheme of the application is clearer, the technical scheme of the application is described in detail below with reference to the accompanying drawings and the embodiments.
As shown in fig. 2, which is a schematic block diagram of a switching power supply to which the control method according to the embodiment of the present application is applied, an output current signal I reflecting the magnitude of an output current of the switching power supply is obtained by an output current sampling circuit o_samp The method comprises the steps of carrying out a first treatment on the surface of the Obtaining an output voltage signal V reflecting the output voltage of the switching power supply through an output voltage sampling circuit o_samp The method comprises the steps of carrying out a first treatment on the surface of the Output voltage signal V obtained by sampling o_samp Output current signal I o_samp Respectively sending the signals into a control system for feedback loop operation processing.
For the output current sampling circuit, a sampling resistor is connected in series between a switching power supply power converter and a load to convert the load current into a negative pressure signal representing the output current, and the negative pressure signal is further amplified by reverse operation to obtain an output current signal I which is fed into a control quantity operation unit in a control system o_samp The method comprises the steps of carrying out a first treatment on the surface of the The output voltage sampling circuit adopts a conventional resistor voltage division mode to obtain an output voltage signal V which is sent to a control quantity operation unit in a control system o_samp 。
Aiming at the schematic block diagram shown in fig. 2, the control method of the switching power supply provided by the application is mainly realized by a control system, and the specific control process is as follows:
control system samples output voltage signal V of switching power supply in real time o_samp And output current signal I o_samp The method comprises the steps of carrying out a first treatment on the surface of the Output voltage signal V o_samp The voltage feedback unit enters the control system, compares with a constant voltage threshold (voltage reference) in the voltage feedback unit, and realizes the output voltage stabilizing control of the switching power supply; output current signal I o_samp And the constant current feedback unit enters the control system and performs comparison operation with a constant current threshold value in the constant current feedback unit to realize the output constant current control of the switching power supply.
The control system outputs a voltage signal V o_samp Output current signal I o_samp Constant voltage or constant current control mode judgment (CC/CV control mode judgment) is carried out, and a specific control flow is shown in FIG. 3. When the sampled output voltage signal V o_samp When the voltage is larger than the set constant voltage threshold, the switching power supply works in a constant voltage control mode, and voltage loop feedback operation is executed at the moment; otherwise, the magnitude of the output current signal is further judged, when the output current signal is detected to be larger than the set constant current threshold value, the switching power supply works in the constant current control mode, the constant current loop feedback operation is executed, and otherwise, the control mode of the last state is maintained.
In the constant current control mode, besides the conventional constant current loop feedback operation, the maximum output value of the constant current loop control quantity is limited to limit the maximum output power of the switching power supply, and the specific control flow is shown in fig. 4. According to the output load information, the switching power supply works in a constant voltage control mode under normal conditions, and enters a constant current control mode when the load current is detected to be larger than a constant current threshold value; in a constant current control mode, the switching power supply executes constant current loop feedback operation and further judges a control output value fed back by the constant current loop; if the output value of the constant current loop is smaller than the minimum threshold value of the constant current loop control quantity, limiting the maximum output value of the constant current loop to be the minimum threshold value of the set constant current loop control quantity; otherwise, the maximum output value of the limiting constant current ring is the set limiting control amount.
The setting of the minimum threshold of the constant current loop control quantity can meet the gain requirement of the switching power supply in a constant current state, and the gain requirement of the switching power supply in the constant current state is determined by the topological characteristic of a specific converter of the switching power supply; the set limit control amount can be equal to k times of the normal constant current loop output control amount, wherein k is less than 1; alternatively, the set limit control amount may be equal to a fixed clipping value that varies with the input voltage, which may be measured based on the power characteristics of the power converter itself.
The schematic block diagram of the execution of the specific constant voltage or constant current control mode is shown in fig. 5, and is different from the voltage feedback unit in that the constant current feedback unit performs the limiting process on the feedback control amount output by the constant current loop in addition to the normal loop feedback operation. In general, the voltage loop and the constant current loop operate in parallel, and in any case, the switching power supply only works in one of the control modes, only selects one of the feedback loops for calculation, and then obtains final control quantity information, specifically: when the switching power supply works in a constant voltage control mode, the final control quantity information is voltage loop feedback control quantity information; when the switching power supply works in the constant-current control mode, the final control quantity information is constant-current loop feedback control quantity information.
After the final control quantity information is obtained, PWM pulse modulation is carried out inside the control switch power supply, a driving pulse signal for controlling the power converter is generated, and the required control state is finally realized.
When the switching power supply has the fault conditions of overload, short circuit, over-temperature and the like, in order to avoid the problems of energy waste and serious heating caused by long-time constant current operation of the switching power supply, the fault treatment mode of 'first performing constant current protection and then performing hiccup protection' can be adopted so as to improve the reliability of the parallel operation capacity-expansion switching power supply. The constant current protection firstly performed is the switching power supply control method provided by the application; when the set constant current protection time is reached, the switching power supply is controlled to turn off the driving signal, the switching power supply enters a hiccup protection mode, and after the hiccup rest time is reached, the switching power supply tries to restart; if the fault continuously exists, the switching power supply is in a repeated protection mode of constant current and hiccup; and when the fault is eliminated, the switching power supply resumes normal operation.
The experimental verification is carried out on the switching power supply of which the power converter is a resonant converter, and the short-circuit protection performance is verified according to a conventional control method, so that the experimental waveform shown in fig. 6 is obtained, wherein the experimental waveform comprises a load instantaneous power waveform A1, an output current waveform A2, an output voltage waveform A3, a bridge arm tube driving signal waveform A4 of the resonant converter and a bridge arm tube voltage stress waveform A5. It can be seen that the output current suddenly increases at the moment of short circuit, the loop control quantity is not enough to limit the output power because the response speed of the constant current loop is slower, and the reflected driving pulse width signal is wider all the time; eventually triggering primary side peak current protection to the resonant converter.
According to the short-circuit instantaneous output voltage and output current information displayed by the oscilloscope in fig. 6, calculating the instantaneous power absorbed by the load between the occurrence of the short circuit and the entering of the protection of the switching power supply to be 1.98kW, wherein the instantaneous power comprises the output capacitor discharge power and the instantaneous power born by the resonant converter; the output capacitor discharge power can be solved by the output voltage information: the output voltage is reduced from 23.5V to 11.94V, the total output capacitance is 1300uF, and therefore the power released on the output capacitance can be calculated to be 811.8W; the remaining power is the instantaneous power passing through the resonant converter itself in the short-circuit stage is 1168W/1ms, and the partial power is completely borne by the rectifying tube of the resonant converter, so that the performance requirement on the rectifying tube at the secondary side is higher, and the breakdown risk of the rectifying tube easily occurs.
The control method and the control system of the switching power supply are applied to the resonant converter for experimental verification, and experimental waveforms shown in fig. 7 are obtained under the same working condition, wherein the experimental waveforms comprise a load instantaneous power waveform B1, an output current waveform B2, an output voltage waveform B3 and a bridge arm tube driving signal waveform B4. It can be seen that when the secondary side is short-circuited, the output current is increased, once the condition of entering the constant current control is met, the loop feedback control quantity is subjected to amplitude limiting treatment, the reflected driving pulse width signal is obviously reduced, the output power is effectively limited, then the switching power supply enters a constant current control mode, and the output current is constant at a set threshold value after fluctuation adjustment.
Because the output power is effectively limited, the primary side peak current protection of the resonant converter is not triggered by the switching power supply, and the instantaneous power absorbed by the load between the short circuit and the entering of the constant current protection can be calculated to be 1.86kW according to the short circuit constant current instantaneous output voltage and output current information displayed by the oscilloscope in fig. 7, wherein the part comprises the power discharged by the output capacitor and the instantaneous power born by the converter; the output capacitor discharge power can be solved by the output voltage information: the output voltage is reduced from 23.5V to 11.12V, and the total output capacitance is 1300uF, so that the power released on the output capacitance can be calculated to be 931W; the remaining power is the instantaneous power which is short-circuited to enter the constant current protection stage and passes through the converter is 929W/1ms; compared with the conventional constant current control method, 239W/1ms is reduced, and the converter is more reliable.
The control method of the switching power supply and the control switching power supply thereof provided by the application have higher practicability and reliability, can realize accurate output current control, can effectively limit the output power of the converter when the output current is overlarge, avoid overstress and overheat damage risks of switching devices, and effectively improve the reliability of the switching power supply; meanwhile, synchronous startup of each switching power supply in the parallel operation capacity expansion system is guaranteed, and an implementation thought is provided for parallel operation capacity expansion application of the switching power supplies.
The above embodiments are only for aiding in understanding the inventive concept and are not intended to limit the application, and any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art without departing from the principles of the present application should be included in the scope of the present application.
Claims (6)
1. A control method of a switching power supply, characterized by comprising:
sampling an output current signal reflecting the magnitude of the output current of the switching power supply; sampling an output voltage signal reflecting the magnitude of the output voltage of the switching power supply;
judging the sizes of an output voltage signal and an output current signal, and determining the working mode of the switching power supply:
when the output voltage signal is larger than a set constant voltage threshold, the switching power supply works in a constant voltage control mode, and the voltage loop feedback operation unit acts to obtain voltage loop feedback control quantity information;
when the output voltage signal is smaller than the set constant voltage threshold, the magnitude of the output current signal is further judged, and when the output current signal is larger than the set constant current threshold, the switching power supply works in a constant current control mode, at the moment, the constant current loop feedback operation unit acts to obtain constant current loop feedback control quantity information, and otherwise, the control mode of the last state is maintained;
when the switching power supply works in a constant current control mode, constant current loop feedback operation is carried out, and the maximum output power of the switching power supply is limited by limiting the maximum output value of the constant current loop control quantity, and the switching power supply is specific:
in the constant current control mode, the switching power supply executes constant current loop feedback operation to further judge the constant current loop feedback control quantity information; if the information of the constant-current loop feedback control quantity is smaller than the minimum threshold value of the constant-current loop control quantity, limiting the maximum output value of the constant-current loop to be the minimum threshold value of the constant-current loop control quantity; otherwise, the maximum output value of the limiting constant current ring is the set limiting control amount.
2. The method according to claim 1, wherein the setting of the minimum threshold of the constant current loop control amount is capable of meeting a gain requirement of the switching power supply in a constant current state, and the gain requirement of the switching power supply in the constant current state is determined by a topology characteristic of a converter in the switching power supply.
3. The control method of a switching power supply according to claim 1, wherein the set limit control amount is equal to k times the normal constant current loop output control amount or equal to a fixed clipping value varying with an input voltage, where k < 1; the fixed limiting value which varies with the input voltage is measured according to the power characteristics of the switching power supply.
4. The control method of a switching power supply according to claim 1, wherein the voltage loop feedback control amount information is obtained by judgment of a constant voltage control mode and loop operation; and obtaining the obtained constant current loop feedback control quantity information through judgment of the constant current control mode and loop operation.
5. The method according to claim 4, wherein when the switching power supply is operated in the constant voltage control mode, the voltage loop feedback control amount information is converted into a driving signal for controlling a power switching transistor of the switching power supply; when the switching power supply works in a constant-current control mode, the constant-current loop feedback control quantity information is converted into a driving signal for controlling a power switch tube of the switching power supply.
6. A control system for a switching power supply, comprising:
the voltage feedback unit is used for controlling the switching power supply to output constant voltage by sampling an output voltage signal of the switching power supply to perform constant voltage loop feedback operation;
the constant current feedback unit is used for controlling the switching power supply to output constant current by sampling an output current signal of the switching power supply to perform constant current loop feedback operation;
the control quantity operation unit is used for controlling the switching power supply to work in a constant voltage control mode or a constant current control mode according to the output voltage signal and the output current signal; when the switching power supply works in a constant voltage control mode, executing voltage loop operation processing to acquire voltage loop feedback control quantity information; when the switching power supply works in the constant current control mode, constant current loop operation processing is executed, and constant current loop feedback control quantity information is obtained;
the PWM pulse modulation unit is used for converting the feedback control quantity information of the voltage loop into a driving signal for controlling a power switch tube of the switching power supply when the switching power supply works in a constant voltage control mode; and the power switch tube is used for converting the information of the feedback control quantity of the constant current loop into a driving signal for controlling the power switch tube of the switching power supply when the switching power supply works in the constant current control mode.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117463506A (en) * | 2023-12-26 | 2024-01-30 | 浙江佳环电子有限公司 | Self-adaptive constant-current constant-voltage control high-voltage power supply |
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2023
- 2023-01-31 CN CN202310048495.4A patent/CN116633142A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117463506A (en) * | 2023-12-26 | 2024-01-30 | 浙江佳环电子有限公司 | Self-adaptive constant-current constant-voltage control high-voltage power supply |
| CN117463506B (en) * | 2023-12-26 | 2024-03-22 | 浙江佳环电子有限公司 | Self-adaptive constant-current constant-voltage control high-voltage power supply |
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