CN113206591A - Overload protection method and overload protection device for load - Google Patents
Overload protection method and overload protection device for load Download PDFInfo
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- CN113206591A CN113206591A CN202110488648.8A CN202110488648A CN113206591A CN 113206591 A CN113206591 A CN 113206591A CN 202110488648 A CN202110488648 A CN 202110488648A CN 113206591 A CN113206591 A CN 113206591A
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- 238000000034 method Methods 0.000 title claims abstract description 10
- 238000001514 detection method Methods 0.000 claims abstract description 18
- 238000005070 sampling Methods 0.000 claims description 46
- 230000003287 optical effect Effects 0.000 claims description 9
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 2
- 230000000087 stabilizing effect Effects 0.000 claims description 2
- 238000013021 overheating Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000001012 protector Effects 0.000 description 1
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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
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1203—Circuits independent of the type of conversion
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention belongs to the technical field of loads, and particularly relates to a method for improving overload protection of a load and an overload protection device, which comprise a feedback control unit and a current loop unit, wherein the feedback control unit comprises a first detection unit, a control unit, a feedback unit and a voltage loop unit; the current loop unit is arranged between the feedback unit and the voltage loop unit and is configured to limit the output current of the power supply under the condition that the load of the power supply is overloaded or short-circuited; therefore, according to the scheme of the invention, as the duty ratio of the pulse width modulation signal generated by the control unit is changed from small to large, the conduction time of the voltage loop unit is changed from short to long, the current flowing into the load is changed from small to large, and the damage capability of the instantaneous power supply element generating large surge current when the load is connected with the current loop unit is weakened.
Description
Technical Field
The invention belongs to the technical field of loads, and particularly relates to a load overload protection method and a load overload protection device.
Background
The overload protection is overload protection equipment which is additionally arranged for preventing a protector from being damaged due to overheating caused by overload of a main power supply line, the current amount which is allowed to continuously pass through an electric line and can not cause overheating of an electric wire is called safe current-carrying capacity or safe current, when the current flowing through a lead is larger than the safe current-carrying capacity when the load is too large, the current flowing through the lead is larger than the safe current-carrying capacity, the lead is called overload, the temperature of the lead is increased due to overload of the lead, the maximum allowable working temperature of the lead is generally 65 ℃, when the lead is overloaded, the temperature of the lead is higher than the maximum allowable working temperature, the insulation layer of the lead is rapidly aged, even the line burns to cause fire, therefore, in an actual power supply line, the overload protection equipment is generally used for preventing the potential safety hazard caused by overload of the load.
Disclosure of Invention
In order to solve the above problems, the present invention provides a load overload protection method and an overload protection apparatus, and a load protection circuit for preventing load damage.
The technical scheme adopted by the invention is as follows:
a load overload protection device comprises a feedback control unit and a current loop unit, wherein the feedback control unit comprises a first detection unit, a control unit, a feedback unit and a voltage loop unit; the current loop unit is arranged between the feedback unit and the voltage loop unit and is configured to limit the output current of the power supply under the condition that the load of the power supply is overloaded or short-circuited; the first detection unit is used for generating a trigger signal when detecting that the load is connected with the current loop unit; the feedback unit is used for generating a pulse width modulation signal with a preset duty ratio to the control unit when receiving the trigger signal; the control unit is used for receiving the pulse width modulation signal and periodically controlling the voltage loop unit to switch on or off the electrical connection between the power supply and the load; wherein the duty ratio of the pulse width modulation signal is gradually increased; the on-time of the voltage loop unit is gradually increased, and the off-time is gradually reduced; the feedback control unit also comprises a second detection unit, one end of the second detection unit is connected with the control unit, and the other end of the second detection unit is connected between the feedback unit and the current loop unit; the second detection unit is used for detecting the voltage received by the feedback unit to generate a sampling voltage; the control unit is also used for starting timing and accumulating sampling time after receiving the trigger signal, and comparing the sampling time with the first preset time; if the current sampling time is less than the first preset time, the control unit compares the sampling voltage with each threshold voltage.
An overload protection method comprises the following steps:
acquiring current sampling voltage and accumulating sampling time:
judging whether the current sampling time is less than a first preset time or not;
if the current sampling voltage is not equal to the sampling voltage at the previous moment, resetting the detection time and sequentially comparing the current sampling voltage with a plurality of threshold voltages;
and outputting a pulse width modulation signal with a duty ratio corresponding to the threshold voltage.
In some embodiments, the current loop unit is further configured to disable the current loop unit itself and operate the voltage loop unit so that the power supply normally supplies power to the load, in a case where the load of the power supply is normal, or in a case where the load of the power supply is overloaded or the short circuit has been released.
In some embodiments, the feedback unit comprises an optical coupling element, and the voltage loop unit comprises a voltage regulator element and a filter element; the cathode of the voltage-stabilizing source element is connected to the cathode of a diode side in the optical coupler element and is also connected to the reference electrode of the voltage-stabilizing source element after passing through the filter element, and the anode of the voltage-stabilizing source element is connected to the sampling voltage.
In some embodiments, the control unit comprises a pulse control element, a power supply element, and a sampling element; the non-inverting input end of the feedback unit is connected to the sampling element and the power supply element; the inverting input end of the feedback unit is connected to a collector electrode on the transistor side in the optical coupling element; and the output end of the feedback unit is connected to the control end of the power supply element after passing through the pulse control element.
In some embodiments, the current loop unit disables itself and operates the voltage loop unit, and includes sampling a load voltage through the sampling element, comparing the sampled load voltage with a threshold voltage, and outputting a pulse width modulation signal having a duty ratio corresponding to the threshold voltage; by the power supply element, when the voltage of the control end of the power supply element is less than or equal to the threshold voltage of the power supply element, the power supply element is turned off, so that the current loop unit is turned off, and the voltage loop unit is operated.
Therefore, according to the scheme of the invention, as the duty ratio of the pulse width modulation signal generated by the control unit is changed from small to large, the conduction time of the voltage loop unit is changed from short to long, the current flowing into the load is changed from small to large, and the damage capability of the instantaneous power supply element generating large surge current when the load is connected with the current loop unit is weakened;
through setting up the current loop at power output end, restrict load current, when taking place output load overload trouble, protection circuit can be quick timely start protection, if solve the power and do not restrict load current, can influence the problem of load security when the load overloads even the short circuit.
Drawings
FIG. 1 is a functional block diagram of a load protection device according to a preferred embodiment;
FIG. 2 is a flow chart of a load protection method according to a preferred embodiment.
Detailed Description
As shown in fig. 1, a load overload protection device includes a feedback control unit and a current loop unit, where the feedback control unit includes a first detection unit 1, a control unit 3, a feedback unit 2, and a voltage loop unit 4; the current loop unit 6 is arranged between the feedback unit 2 and the voltage loop unit 4, and is configured to limit the output current of the power supply in case of overload or short circuit of the load of the power supply; the first detecting unit 1 is used for generating a trigger signal when detecting that the load is connected with the current loop unit 6; the feedback unit 2 is used for generating a pulse width modulation signal with a preset duty ratio to the control unit 3 when receiving a trigger signal; the control unit 3 is used for receiving the pulse width modulation signal and periodically controlling the voltage loop unit 4 to switch on or off the electrical connection between the power supply and the load; wherein the duty ratio of the pulse width modulation signal is gradually increased; the voltage loop unit 4 has gradually increased on-time and gradually decreased off-time; the feedback control unit further comprises a second detecting unit 5, one end of the second detecting unit 5 is connected with the control unit 3, and the other end is connected between the feedback unit 2 and the current loop unit 6; the second detecting unit 5 is configured to detect a voltage received by the feedback unit 2 to generate a sampling voltage; the control unit 3 is also used for starting timing and accumulating sampling time after receiving the trigger signal, and comparing the sampling time with the first preset time; if the current sampling time is less than the first predetermined time, the control unit 3 compares the sampling voltage with each threshold voltage.
As shown in fig. 2, an overload protection method includes the following steps:
s201 takes the current sample voltage and accumulates the sample time:
s202, judging whether the current sampling time is less than a first preset time;
s203 if the current sampling voltage is not equal to the previous sampling voltage;
s204, starting to accumulate the detection time;
s205 detecting that the time is greater than a second predetermined time;
s206 clearing the detection time and comparing the current sampling voltage with a plurality of threshold voltages in sequence;
s207 outputs a pulse width modulation signal having a duty ratio corresponding to the threshold voltage;
s208 whether the current sample voltage is equal to the reference voltage;
s209 controls the voltage ring unit to be continuously turned on.
The current loop unit 6 is further configured to disable the current loop unit 6 itself and operate the voltage loop unit 4 so that the power supply normally supplies power to the load, in a case where the load of the power supply is normal, or in a case where the load of the power supply is overloaded or the short circuit is released.
The feedback unit 2 comprises an optical coupling element, and the voltage loop unit 4 comprises a voltage stabilizing source element and a filtering element; the cathode of the voltage-stabilizing source element is connected to the cathode of a diode side in the optical coupler element and is also connected to the reference electrode of the voltage-stabilizing source element after passing through the filter element, and the anode of the voltage-stabilizing source element is connected to the sampling voltage.
The control unit 3 comprises a pulse control element, a power supply element and a sampling element; wherein, the non-inverting input terminal of the feedback unit 2 is connected to the sampling element and also connected to the power supply element; the inverting input end of the feedback unit 2 is connected to the collector electrode on the transistor side in the optical coupling element; the output end of the feedback unit 2 is connected to the control end of the power supply element after passing through the pulse control element.
The current loop unit 6 is used for forbidding the current loop unit 6 and enabling the voltage loop unit 4 to work, and comprises the steps of sampling load voltage through the sampling element, comparing the sampled load voltage with threshold voltage, and outputting a pulse width modulation signal with a duty ratio corresponding to the threshold voltage; through the power supply element, under the condition that the voltage of the control end of the power supply element is less than or equal to the threshold voltage of the power supply element, the power supply element is turned off, so that the current loop unit 6 is closed, and the voltage loop unit 4 works.
Claims (6)
1. A load overload protection device is characterized in that: the current loop control circuit comprises a feedback control unit and a current loop unit, wherein the feedback control unit comprises a first detection unit, a control unit, a feedback unit and a voltage loop unit; the current loop unit is arranged between the feedback unit and the voltage loop unit and is configured to limit the output current of the power supply under the condition that the load of the power supply is overloaded or short-circuited; the first detection unit is used for generating a trigger signal when detecting that the load is connected with the current loop unit; the feedback unit is used for generating a pulse width modulation signal with a preset duty ratio to the control unit when receiving the trigger signal; the control unit is used for receiving the pulse width modulation signal and periodically controlling the voltage loop unit to switch on or off the electrical connection between the power supply and the load; wherein the duty ratio of the pulse width modulation signal is gradually increased; the on-time of the voltage loop unit is gradually increased, and the off-time is gradually reduced; the feedback control unit also comprises a second detection unit, one end of the second detection unit is connected with the control unit, and the other end of the second detection unit is connected between the feedback unit and the current loop unit; the second detection unit is used for detecting the voltage received by the feedback unit to generate a sampling voltage; the control unit is also used for starting timing and accumulating sampling time after receiving the trigger signal, and comparing the sampling time with the first preset time; if the current sampling time is less than the first preset time, the control unit compares the sampling voltage with each threshold voltage.
2. An overload protection method according to claim 1, comprising the steps of:
acquiring current sampling voltage and accumulating sampling time:
judging whether the current sampling time is less than a first preset time or not;
if the current sampling voltage is not equal to the sampling voltage at the previous moment, resetting the detection time and sequentially comparing the current sampling voltage with a plurality of threshold voltages;
and outputting a pulse width modulation signal with a duty ratio corresponding to the threshold voltage.
3. A load overload protection apparatus according to claim 1, wherein: the current loop unit is also configured to disable the current loop unit itself and operate the voltage loop unit so that the power supply normally supplies power to the load, in a case where the load of the power supply is normal, or in a case where the load of the power supply is overloaded or the short circuit is released.
4. A load overload protection apparatus according to claim 1, wherein: the feedback unit comprises an optical coupling element, and the voltage loop unit comprises a voltage stabilizing source element and a filtering element; the cathode of the voltage-stabilizing source element is connected to the cathode of a diode side in the optical coupler element and is also connected to the reference electrode of the voltage-stabilizing source element after passing through the filter element, and the anode of the voltage-stabilizing source element is connected to the sampling voltage.
5. A load overload protection apparatus according to claim 1, wherein: the control unit comprises a pulse control element, a power supply element and a sampling element; the non-inverting input end of the feedback unit is connected to the sampling element and the power supply element; the inverting input end of the feedback unit is connected to a collector electrode on the transistor side in the optical coupling element; and the output end of the feedback unit is connected to the control end of the power supply element after passing through the pulse control element.
6. A load overload protection apparatus according to claim 1, wherein: the current loop unit enables the current loop unit to be forbidden and enables the voltage loop unit to work, and the method comprises the steps of sampling load voltage through the sampling element, comparing the sampled load voltage with threshold voltage, and outputting a pulse width modulation signal with a duty ratio corresponding to the threshold voltage; by the power supply element, when the voltage of the control end of the power supply element is less than or equal to the threshold voltage of the power supply element, the power supply element is turned off, so that the current loop unit is turned off, and the voltage loop unit is operated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110488648.8A CN113206591A (en) | 2021-04-30 | 2021-04-30 | Overload protection method and overload protection device for load |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110488648.8A CN113206591A (en) | 2021-04-30 | 2021-04-30 | Overload protection method and overload protection device for load |
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| CN113206591A true CN113206591A (en) | 2021-08-03 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202110488648.8A Pending CN113206591A (en) | 2021-04-30 | 2021-04-30 | Overload protection method and overload protection device for load |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683242A (en) * | 2012-09-25 | 2014-03-26 | 鸿富锦精密工业（深圳）有限公司 | Load protection circuit |
| CN104466886A (en) * | 2013-09-18 | 2015-03-25 | 鸿富锦精密工业（深圳）有限公司 | Load protection circuit and load protection method |
-
2021
- 2021-04-30 CN CN202110488648.8A patent/CN113206591A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683242A (en) * | 2012-09-25 | 2014-03-26 | 鸿富锦精密工业（深圳）有限公司 | Load protection circuit |
| CN104466886A (en) * | 2013-09-18 | 2015-03-25 | 鸿富锦精密工业（深圳）有限公司 | Load protection circuit and load protection method |
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Application publication date: 20210803 |
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