CN112072903A - Load protection device and method of flyback transformer switching power supply and electrical equipment - Google Patents

Load protection device and method of flyback transformer switching power supply and electrical equipment Download PDF

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Publication number
CN112072903A
CN112072903A CN202010885927.3A CN202010885927A CN112072903A CN 112072903 A CN112072903 A CN 112072903A CN 202010885927 A CN202010885927 A CN 202010885927A CN 112072903 A CN112072903 A CN 112072903A
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CN
China
Prior art keywords
module
voltage
power supply
load
switching power
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Pending
Application number
CN202010885927.3A
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Chinese (zh)
Inventor
冷正明
游健康
刘江
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Priority to CN202010885927.3A priority Critical patent/CN112072903A/en
Publication of CN112072903A publication Critical patent/CN112072903A/en
Pending legal-status Critical Current

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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
    • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
    • 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
    • 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
    • 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
    • H02M1/325—Means for protecting converters other than automatic disconnection with means for allowing continuous operation despite a fault, i.e. fault tolerant converters

Abstract

The invention discloses a load protection device, a method and electrical equipment of a flyback transformer switching power supply, wherein the device comprises: the flyback transformer switching power supply comprises: the system comprises an input power module, a transformer module and a feedback control module; the feedback control module includes: the device comprises a feedback module, a voltage loop module, a comparison module and a control module; the load protection device of the flyback transformer switching power supply comprises: a current loop module; the current loop module is arranged between the feedback module and the voltage loop module and is configured to limit the output current of the flyback transformer switching power supply under the condition that the load of the flyback transformer switching power supply is overloaded or short-circuited, so that the load protection of the flyback transformer switching power supply is realized. According to the scheme, the load current of the switching power supply of the flyback transformer is limited, and the influence on the load safety when the load is overloaded or even short-circuited can be avoided.

Description

Load protection device and method of flyback transformer switching power supply and electrical equipment
Technical Field
The invention belongs to the technical field of power protection, and particularly relates to a load protection device and method for a flyback transformer switching power supply and electrical equipment, in particular to a novel protection circuit and method for overload of a flyback power supply circuit output side load in an electric automobile and electrical equipment.
Background
Under the condition that the load current is not limited, the flyback transformer switching power supply can affect the load safety when the load is overloaded or even short-circuited.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention aims to provide a load protection device, a method and electrical equipment of a flyback transformer switching power supply, so as to solve the problem that if the flyback transformer switching power supply does not limit the load current, the load safety is affected when the load is overloaded or even short-circuited, and achieve the effect of avoiding the load safety from being affected when the load is overloaded or even short-circuited by limiting the load current.
The invention provides a load protection device of a flyback transformer switching power supply, which comprises: the system comprises an input power module, a transformer module and a feedback control module; the feedback control module includes: the device comprises a feedback module, a voltage loop module, a comparison module and a control module; the load protection device of the flyback transformer switching power supply comprises: a current loop module; the current loop module is arranged between the feedback module and the voltage loop module and is configured to limit the output current of the flyback transformer switching power supply under the condition that the load of the flyback transformer switching power supply is overloaded or short-circuited, so that the load protection of the flyback transformer switching power supply is realized.
In some embodiments, further comprising: the current loop module is further configured to disable the current loop module and enable the voltage loop module to operate under the condition that the load of the flyback transformer switching power supply is normal or the condition that the load overload or short circuit of the flyback transformer switching power supply is relieved, so that the flyback transformer switching power supply normally supplies power to the load.
In some embodiments, the feedback module comprises: an optocoupler module; the current loop module includes: the sampling device comprises a first switch module, a first voltage division module, a second voltage division module and a first sampling module; the first switch end of the first switch module is connected to a cathode of a diode side in the optical coupling module and is also connected to the voltage ring module; the control end of the first switch module is connected to the first end of the first sampling module after passing through the first voltage division module, and is also connected to the second end of the first sampling module after passing through the second voltage division module; the first end of the first sampling module is connected to a load, and the second end of the first sampling module is connected to the second switch end of the first switch module.
In some embodiments, the voltage ring module comprises: the voltage stabilizing source module, the filtering module, the third voltage dividing module and the fourth voltage dividing module; the cathode of the voltage stabilizing source module is connected to the cathode of a diode side in the optical coupling module and is also connected to the reference pole of the voltage stabilizing source module after passing through the filtering module; the third voltage division module and the fourth voltage division module are connected in series and then connected in parallel with a load, and the common end of the third voltage division module and the common end of the fourth voltage division module are connected to the reference electrode of the voltage stabilizing source module; and the anode of the voltage-stabilizing source module is connected to the first end of the first sampling module.
In some embodiments, the control module comprises: the pulse control module, the second switch module and the second sampling module; the non-inverting input end of the comparison module is connected to the second sampling module and is also connected to the second switch end of the second switch module; the inverting input end of the comparison module is connected to a collector electrode on the transistor side in the optical coupling module; the output end of the comparison module is connected to the control end of the second switch module after passing through the pulse control module; and the first switching end of the second switching tube is connected to the primary winding of the transformer module.
In some embodiments, the current loop module, limiting the output current of the flyback transformer switching power supply, includes: sampling, by the first sampling module, a load voltage; dividing the sampled load voltage through the first voltage division module and the second voltage division module to obtain divided voltage; by the first switch module, in the case that the divided voltage of the control terminal of the first switch module is greater than a threshold voltage of the first switch module: if the load is overloaded, the first switch module is conducted and replaces the voltage stabilizing source module, so that the current loop module replaces the voltage loop module to work, the duty ratio of the control end of the second switch module is reduced, and the output voltage of the switching power supply of the flyback transformer is controlled to be reduced; and if the load is short-circuited, the voltage loop module is short-circuited, and the first switch module is switched on, so that the flyback transformer switching power supply is used as a constant current generator.
In some embodiments, the current loop module, having the current loop module itself disabled, and having the voltage loop module operational, comprises: sampling, by the first sampling module, a load voltage; dividing the sampled load voltage through the first voltage division module and the second voltage division module to obtain divided voltage; through the first switch module, under the condition that the divided voltage at the control end of the first switch module is less than or equal to the threshold voltage of the first switch module, the first switch module is turned off, so that the current loop module is turned off, and the voltage loop module is enabled to work.
In accordance with another aspect of the present invention, there is provided an electrical apparatus, including: the load protection device of the flyback transformer switching power supply is described above.
In another aspect, the present invention provides a method for protecting a load of a flyback transformer switching power supply of an electrical device, the method comprising: through the current loop module, under the condition that the load of the flyback transformer switching power supply is overloaded or short-circuited, the output current of the flyback transformer switching power supply is limited, so that the load protection of the flyback transformer switching power supply is realized.
In some embodiments, further comprising: through the current loop module, under the condition that the load of the flyback transformer switching power supply is normal or the condition that the load overload or short circuit of the flyback transformer switching power supply is relieved, the current loop module is forbidden, and the voltage loop module works, so that the flyback transformer switching power supply normally supplies power to the load.
In some embodiments, limiting the output current of the flyback transformer switching power supply by a current loop module includes: sampling the load voltage through a first sampling module; dividing the sampled load voltage through a first voltage division module and a second voltage division module to obtain divided voltage; by a first switch module, in the case that the divided voltage at the control terminal of the first switch module is greater than a threshold voltage of the first switch module: if the load is overloaded, the first switch module is conducted and replaces a voltage stabilizing source module, the current loop module replaces a voltage loop module, the duty ratio of the second switch module is reduced, and therefore the output voltage of the flyback transformer switching power supply is controlled to be reduced; and if the load is short-circuited, the voltage loop module is short-circuited, and the first switch module is switched on, so that the flyback transformer switching power supply is used as a constant current generator.
In some embodiments, disabling the current loop module itself and operating the voltage loop module by the current loop module comprises: sampling the load voltage through a first sampling module; dividing the sampled load voltage through a first voltage division module and a second voltage division module to obtain divided voltage; through the first switch module, under the condition that the divided voltage at the control end of the first switch module is less than or equal to the threshold voltage of the first switch module, the first switch module is turned off, so that the current loop module is turned off, and the voltage loop module is operated.
Therefore, according to the scheme provided by the invention, the current loop is arranged at the output end of the switching power supply of the flyback transformer to limit the load current, when the output load overload fault occurs, the protection circuit can be started and protected quickly and timely, the problem that the load safety is influenced when the load is overloaded or even short-circuited if the switching power supply of the flyback transformer does not limit the load current is solved, and the effect of limiting the load current of the switching power supply of the flyback transformer to avoid the influence on the load safety when the load is overloaded or even short-circuited is achieved.
Specifically, through setting up the current loop at vehicle mounted power source (flyback transformer switching power supply promptly) output, restrict load current, when taking place output load overload trouble, protection circuit can be fast timely start protection, solve the automobile power source if not restricting load current, can influence the problem of whole car security when the load overloads even the short circuit, reach through restricting load current in order to avoid influencing the effect of whole car security when the load overloads even the short circuit.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of a load protection device of a flyback transformer switching power supply according to the present invention;
fig. 2 is a schematic structural diagram of an embodiment of an output load overload protection circuit of a power supply (i.e., a flyback transformer switching power supply);
FIG. 3 is a schematic diagram of the output characteristic curve of the power supply (i.e., the flyback transformer switching power supply);
fig. 4 is a schematic flowchart of an embodiment of limiting the output current of the flyback transformer switching power supply in the load protection method of the flyback transformer switching power supply of the present invention;
fig. 5 is a schematic flow chart illustrating an embodiment of disabling the current loop module in the load protection method for the flyback transformer switching power supply according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
According to an embodiment of the invention, a load protection device of a flyback transformer switching power supply is provided. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The load protection device of the flyback transformer switching power supply can be applied to the aspect of load overload or short-circuit protection of the flyback power supply (namely the flyback transformer switching power supply) of a pure electric vehicle. In load overload or short-circuit protection of a flyback power supply (i.e., a flyback transformer switching power supply) of a pure electric vehicle, the flyback transformer switching power supply may include: the power supply comprises an input power supply module (such as an input power supply A), a transformer module and a feedback control module. The feedback control module can include: the device comprises a feedback module, a voltage loop module (such as a voltage loop D), a comparison module and a control module. The input power supply module (such as an input power supply A) is connected to the primary winding of the transformer module, and the secondary winding of the transformer module is output to a load after passing through the feedback module and the voltage loop module. The secondary winding of the transformer module is fed back to the primary winding of the transformer module after passing through the feedback module, the comparison module and the control module.
In load overload or short-circuit protection of a flyback power supply (i.e., a flyback transformer switching power supply) of a pure electric vehicle, the load protection device of the flyback transformer switching power supply may include: a current loop module (e.g., current loop C).
Specifically, the current loop module is arranged between the feedback module and the voltage loop module, and can be configured to be in the case that the load at the output end of the flyback transformer switching power supply is overloaded or short-circuited, the voltage loop module is replaced to work or make the voltage loop module short-circuited, and the output current of the flyback transformer switching power supply is limited, so that the load protection of the flyback transformer switching power supply is realized, namely, the overload or short-circuit protection of the load of the flyback transformer switching power supply is realized.
Therefore, the current loop module is additionally arranged at the output end of the flyback transformer switching power supply, the load current can be limited, when an output load overload fault occurs, the protection circuit can be quickly and timely started and protected, the power supply fault is prevented from being expanded, the normal work of other power supplies cannot be influenced, the automobile can be safely parked, and the safety of personnel in the automobile is guaranteed.
In some embodiments, it can further include: and under the condition that the load is normal, namely the load is not overloaded and is not short-circuited, or under the condition that the fault of overload or short circuit of the load is relieved, controlling the control process of normally supplying power to the switching power supply of the flyback transformer.
The current loop module can be further configured to disable the current loop module and enable the voltage loop module to work under the condition that the load at the output end of the flyback transformer switching power supply is normal or the condition that the load overload or short circuit at the output end of the flyback transformer switching power supply is relieved, so that the flyback transformer switching power supply can normally supply power to the load.
Specifically, under the condition that the load is normal, namely the load is not overloaded and short-circuited, the current loop module is forbidden, and the voltage loop module works normally, so that the flyback transformer switching power supply supplies power to the load normally; and under the condition that the overload or short circuit condition of the load at the output end of the flyback transformer switching power supply is relieved, the current loop module is forbidden, and the voltage loop module is recovered to work so as to relieve the load protection of the flyback transformer switching power supply and recover the flyback transformer switching power supply to normally supply power to the load.
Therefore, the current loop module is additionally arranged at the output end of the flyback transformer switching power supply, so that after the fault is eliminated, the power supply can automatically remove the protection state and recover the normal output voltage.
In some embodiments, the input power module (e.g., input power a) can include: a direct current power supply DC, and a capacitor C1 connected in parallel between the positive and negative poles of the direct current power supply DC. The direct current power supply DC can provide a high-voltage direct current power supply, and the capacitor C1 can filter the high-voltage direct current power supply provided by the direct current power supply DC.
The transformer module can include: the isolation flyback transformer (such as a transformer T1), a diode D3 and a capacitor C2, wherein the anode of the direct current power supply DC is connected to the dotted terminal of the primary winding of the transformer T1, and the cathode of the direct current power supply DC is connected to the analog ground. The synonym terminal of the primary winding of the transformer T1 is connected to the control module. The synonym terminal of the secondary winding of the transformer T1 is connected to the anode of the diode D3. The cathode of the diode D3 is connected to the digital ground through the capacitor C2, the same name of the secondary winding of the transformer T1 is connected to the digital ground, the diode D3 can rectify the output side of the transformer, and the capacitor C2 can filter. The secondary winding of the transformer T2 passes through the output side of the capacitor C2, passes through the feedback module, then passes through the current loop module or the voltage loop module, then is output to a load, and further passes through the comparison module and the control module, and then is fed back to the primary winding of the transformer module.
The feedback module can include: and the optical coupling module (such as an optical coupler PC 817). Specifically, the feedback module can include: a current limiting module (such as a resistor R1) and an optocoupler module (such as an optocoupler PC 817); the current limiting module is connected to the anode of the diode side in the optical coupling module from the output side of the secondary winding of the transformer module; cathodes on the sides of diodes in the optical coupling module are respectively connected to the current loop module and the voltage loop module; and a collector electrode at the transistor side in the optical coupling module is connected to the inverting input end of the comparison module.
For example: a resistor R1 is connected from the cathode of the diode D3 to the anode of the diode side in the photocoupler PC 817. The cathodes of the diode sides in the photocoupler PC817 are connected to the current loop module and the voltage loop module, respectively. The collector of the transistor side of the photocoupler PC817 is connected to the inverting input of the comparison module (e.g., the comparator of the voltage comparison module G). The collector of the transistor side in the photoelectric coupler PC817 is also connected to the positive electrode of the direct current power supply Vcc through a pull-up resistor Rpullup, the negative electrode of the direct current power supply Vcc is connected to an analog ground, and the emitter of the transistor side in the photoelectric coupler PC817 is also connected to the analog ground.
The current loop module can include: the circuit comprises a first switching module (such as a transistor Q2), a first voltage division module (such as a resistor R2), a second voltage division module (such as a resistor R3) and a first sampling module (such as a resistor Rcs).
Wherein a first switch end (such as a collector of a transistor Q2) of the first switch module is connected to a cathode of a diode side in the optocoupler module and is also connected to the voltage loop module; a second switch terminal (e.g., an emitter of a transistor Q2) of the first switch module is coupled to a digital ground; a control terminal of the first switching module (e.g., a base of a transistor Q2) is connected to a first terminal of the first sampling module through the first voltage dividing module, and is also connected to a second terminal of the first sampling module through the second voltage dividing module; the first end of the first sampling module is connected to a load, and the second end of the first sampling module is connected to the second switch end of the first switch module.
For example: and a current loop C is added at the output end of the flyback power supply. In the current loop C, an NPN transistor diode Q2 is provided, and three resistors such as a voltage dividing resistor R2, a voltage dividing resistor R3, and a sampling resistor Rcs are provided. The sampling resistor Rcs is used for overload sampling, the voltage dividing resistor R2 and the voltage dividing resistor R3 are used for dividing voltage to control the on and off of the NPN triode Q2, when overload occurs, the NPN triode Q2 is turned on, and the current loop C replaces a voltage loop to work, so that the overload protection effect is achieved.
In some embodiments, the voltage loop module can include: a voltage regulator module (such as a voltage regulator TL431), a filter module (such as a capacitor C3), a third voltage division module (such as a resistor Rupper) and a fourth voltage division module (such as a resistor Rlower). The capacitor C3 also enables loop compensation.
The cathode of the voltage stabilizing source module is connected to the cathode of a diode side in the optical coupling module and is also connected to the reference pole of the voltage stabilizing source module after passing through the filtering module; the third voltage division module and the fourth voltage division module are connected in series and then connected in parallel with a load, and the common end of the third voltage division module and the common end of the fourth voltage division module are connected to the reference electrode of the voltage stabilizing source module; the anode of the regulator module is connected to a first terminal of the first sampling module (e.g., resistor Rcs).
For example: when the load normally works, the voltage Ucs generated at two ends of the resistor Rcs by the current Iout of the load Rout is lower than the threshold voltage of the NPN triode Q2 by the voltage value U3 after being divided by the voltage dividing resistor R2 and the voltage dividing resistor R3, and the power supply maintains the stability of the output voltage through a voltage loop feedback network formed by the photoelectric coupler PC817 and the voltage stabilizing source TL 431.
In some embodiments, the control module can include: the pulse control module (such as the PWM pulse controller H), the second switch module (such as the MOS transistor Q1) and the second sampling module (such as the sampling resistor Rsns).
Wherein the non-inverting input terminal of the comparing module is connected to the second sampling module (e.g. the sampling resistor Rsns) and also connected to the second switching terminal of the second switching module (e.g. the source of the MOS transistor Q1); the inverting input end of the comparison module is connected to a collector electrode on the transistor side in the optical coupling module; the output end of the comparing module is connected to the control end of the second switching module (e.g., the gate of the MOS transistor Q1) after passing through the pulse control module (e.g., the PWM pulse controller H). The first switch end of the second switch tube (for example, the drain of the MOS transistor Q1) is connected to the primary winding of the transformer module, and the drain of the MOS transistor Q1 is connected to the synonym end of the primary winding of the transformer T1.
In some embodiments, the current loop module, in the case of overload or short circuit of the load of the flyback transformer switching power supply, instead of operating or short-circuiting the voltage loop module, limiting the output current of the flyback transformer switching power supply may include: sampling, by the first sampling module, a load voltage; dividing the sampled load voltage through the first voltage division module and the second voltage division module to obtain divided voltage; by the first switch module, in the case that the divided voltage of the control terminal of the first switch module is greater than a threshold voltage of the first switch module:
firstly, if the load is overloaded, the first switch module is switched on and replaces the voltage stabilizing source module, so that the current loop module replaces the voltage loop module to work, the duty ratio of the control end of the second switch module is reduced, and the output voltage of the switching power supply of the flyback transformer is controlled to be reduced. For example: when the load Rout at the output end is overloaded, the current Iout passing through the load Rout is higher than the nominal output current, the voltage Ucs generated at the two ends of the resistor Rcs is increased, the voltage value U3 after voltage division by the voltage dividing resistor R2 and the voltage dividing resistor R3 is increased and is larger than the threshold voltage of the NPN triode Q2, the NPN triode Q2 is conducted and replaces a voltage ring formed by a voltage stabilizing source TL431 to work as a current ring, the current If is increased, the current Ic passing through the transistor side of the photoelectric coupler PC817 is increased, the voltage Ufb is reduced, the duty ratio of the MOS transistor is reduced, the output voltage is reduced, and the circuit is prevented from being damaged by overload of the load.
And secondly, if the load is short-circuited, the voltage ring module is short-circuited, and the first switch module is switched on, so that the flyback transformer switching power supply is used as a constant current generator. For example: when the load Rout is overloaded or even short-circuited, the voltage loop formed by the voltage stabilizing source TL431 is short-circuited and does not work, and the NPN triode Q2 enables the power supply to act as a constant current generator.
Therefore, a current loop is formed by adding devices such as NPN transistors and the like at the output end of the vehicle-mounted power supply, so that the problems that when abnormal overload or even short circuit occurs to a load, power supply faults are not enlarged, normal work of other power supplies is not influenced, and safe parking is not influenced, so that normal work of other functional modules in a vehicle is ensured, the vehicle can be parked safely, and safety of personnel in the vehicle is guaranteed.
In some embodiments, the current loop module, when the load at the output end of the flyback transformer switching power supply is normal or when the overload or short circuit at the output end of the flyback transformer switching power supply is removed, may disable the current loop module itself and operate the voltage loop module, and may include: sampling, by the first sampling module, a load voltage; dividing the sampled load voltage through the first voltage division module and the second voltage division module to obtain divided voltage; through the first switch module, under the condition that the divided voltage at the control end of the first switch module is less than or equal to the threshold voltage of the first switch module, the first switch module is turned off, so that the current loop module is turned off, and the voltage loop module is enabled to work.
For example: when the overload is eliminated, the current Iout is reduced, the voltage U3 is lower than the threshold voltage of the NPN triode Q2, the current loop C is closed, the voltage loop starts to play a control role, and the voltage returns to the normal working voltage.
When the actual output voltage Uout is higher than the nominal output voltage U, the voltage value Ulower of the actual output voltage Uout after voltage division through the resistor Rupper and the resistor Rlower is higher than the internal voltage reference value Uref of the voltage-stabilizing source TL431, the cathode voltage of the voltage-stabilizing source TL431 is reduced, the current If on the diode side through the photocoupler PC817 is increased, the current Ic on the transistor side through the photocoupler PC817 is increased, and the voltage Ufb is reduced. When the voltage Usns (Ip) Rsns at two ends of the primary sampling resistor Rsns of the transformer T1 is higher than the voltage Ufb, the voltage comparator outputs high level, the PWM pulse controller is reset and turned off, and the MOS tube Q1 is turned off; because the voltage Ufb decreases, the primary peak current Ip of the transformer T1, Usns/Rsns, decreases, i.e. the duty cycle of the MOS transistor Q1 decreases, the transfer energy of the transformer T1 decreases, and the secondary output voltage Uout of the transformer T1 decreases, so as to maintain the output voltage stable.
On the contrary, when the actual output voltage Uout is lower than the nominal output voltage U, the voltage value Ulower of the actual output voltage Uout after voltage division through the resistor Rupper and the resistor Rlower is lower than the internal voltage reference value Uref of the voltage stabilizing source TL431, the cathode of the voltage stabilizing source TL431 is disconnected, the current If on the diode side through the photocoupler PC817 is 0, the current Ic on the transistor side through the PC817 is 0, and the voltage Ufb is increased, so that the primary side peak current Ip of the transformer T1 is increased by us/Rsns, that is, the duty ratio of the MOS transistor is increased, the transfer energy of the transformer is increased, and the secondary side output voltage Uout is increased to maintain the output voltage stable and constant.
Through a large number of tests, the technical scheme of the invention is adopted, the load current is limited by arranging the current loop at the output end of the vehicle-mounted power supply, when the output load overload fault occurs, the protection circuit can be started and protected quickly and timely, the power supply fault is ensured not to be expanded, the normal work of other power supplies is not influenced, the automobile can be parked safely, and the safety of personnel in the automobile is ensured.
According to the embodiment of the invention, an electrical device (such as an automobile) corresponding to the load protection device of the flyback transformer switching power supply is also provided. The electrical device (e.g. an automobile) may be capable of comprising: the load protection device of the flyback transformer switching power supply is described above.
The load overload protection circuits of power supplies are various, but the protection purpose of these protection circuits is usually to solve the problem of burning out the power switch tube. The protection circuit generally does not strictly limit the load current so as to avoid the problem that the power supply cannot be started normally due to the fact that the protection circuit cannot adapt to the load circuit and is connected with the large-capacity filter capacitor in parallel.
With the development of the new energy electric automobile industry, the problem of functional safety of automobile electronic equipment is more and more emphasized by the industry. The electric automobile is different from the traditional automobile, the power of the electric automobile is only provided by a high-voltage direct-current storage battery, a three-phase alternating current is generated by an inverter formed by IGBT (insulated gate bipolar transistor) to drive a motor, the running of the automobile is completed, and the stable work of the power supply cannot be avoided when the whole control logic and the function of the electric automobile are realized.
In some embodiments, the present invention provides a good overload protection circuit for power supply, which can be used in electric vehicles, industrial applications, household appliances, and the like. For example: the utility model provides a novel a protection circuit that is arranged in electric automobile to swashs formula power supply circuit output side load overload, the design circuit practicality, and is ingenious, and is with low costs, has improved car security performance, is fit for the work occasion of controller power in all electric automobile. The circuit can limit load current, when an output load overload fault occurs, the protection circuit can be started and protected quickly and timely, power supply faults are not enlarged, normal work of other power supplies cannot be influenced, an automobile can be parked safely, and safety of personnel in the automobile is guaranteed. After the fault is eliminated, the power supply can automatically remove the protection state and recover the normal output voltage.
In the scheme of the invention, the NPN transistor and other devices are added at the output end of the vehicle-mounted power supply to form a current loop, so that the problems that when abnormal overload or even short circuit occurs to a load, the power supply fault is not enlarged, the normal work of other power supplies is not influenced, and the safe parking is not influenced, thereby ensuring the normal work of other functional modules in the vehicle, ensuring the safe parking of the vehicle and ensuring the safety of personnel in the vehicle. When the fault is eliminated, the current loop of the power supply is forbidden, the protection state is removed, the normal output voltage is recovered, the power-on reset is not needed, and the protection mode is more reliable and intelligent. The circuit is low in cost, and the safety performance of the automobile is improved only by adding the NPN transistor and the resistor device.
In the scheme of the invention, devices such as NPN transistors and the like are added at the output end of the flyback power supply to form a current loop, and a load overload protection circuit is designed, so that when abnormal overload or even short circuit occurs to a load, the output current can be limited, the load can be immediately protected, the power supply fault is prevented from being expanded, the normal work of other power supplies is not influenced, the normal work of other functional modules of the automobile is not influenced, the automobile can be safely parked, and the safety of personnel in the automobile is guaranteed. After the fault is eliminated, the power supply can automatically remove the protection state and recover the normal output voltage.
The following describes an exemplary implementation process of the scheme of the present invention with reference to the examples shown in fig. 2 and fig. 3.
Fig. 2 shows an output load overload protection circuit of a power supply (i.e., a flyback transformer switching power supply). As shown in fig. 2, the output load overload protection circuit of the power supply includes: the circuit comprises an input power supply A, an isolation flyback transformer B (such as a transformer T1), an MOS tube Q1, a pulse controller H (such as a PWM controller), a primary sampling resistor Rsns, a diode D3, a capacitor C2, a resistor R1, a photoelectric coupler PC817, a current loop C, a voltage loop D, a load E (such as a load resistor Rout), an optical coupler feedback module F and a voltage comparison module G. An input power supply A comprising: DC power supply DC and capacitor C1. A current loop C comprising: triode Q2, divider resistance R2, divider resistance R3 and overload sampling resistance Rcs. A voltage ring D comprising: voltage regulator TL431, capacitor C3, voltage dividing resistor Rupper and voltage dividing resistor Rlower. An optocoupler feedback module F, comprising: a direct current power supply Vcc, a transistor side of a photoelectric coupler PC817 and a resistor Rpulup. A voltage comparison module G comprising: a comparator.
The capacitor C1 is connected in parallel between the positive pole of the DC power supply DC and the negative pole of the DC power supply DC. The negative pole of the direct current power supply DC is connected with the analog ground. The positive electrode of the direct-current power supply DC is also connected to the dotted terminal of the primary winding of the transformer T1, the synonym terminal of the primary winding of the transformer T1 is connected to the drain electrode of the MOS tube Q1, and the grid electrode of the MOS tube Q1 is connected to the output end of the comparator after passing through the PWM controller. The source of the MOS transistor Q1 is connected with the analog ground after passing through the primary sampling resistor Rsns. The source of the MOS transistor Q1 is also connected to the non-inverting input of the comparator, whose inverting input is connected to the transistor-side collector of the photocoupler PC 817. The collector electrode of the transistor side of the photoelectric coupler PC817 is also connected with the positive electrode of the direct current power supply Vcc through a resistor Rpulup, the emitter electrode of the transistor side of the photoelectric coupler PC817 is connected with the analog ground, and the negative electrode of the direct current power supply Vcc is connected with the analog ground. The synonym terminal of the secondary winding of the transformer T1 is connected to the anode of the diode D3, the synonym terminal of the secondary winding of the transformer T1 is connected to the analog ground, and the cathode of the diode D3 is connected to the digital ground after passing through the capacitor C2. The cathode of the diode D3 is also connected to the anode of the diode side of the photoelectric coupler PC817 through the resistor R1, the cathode of the diode side of the photoelectric coupler PC817 is connected to the collector of the triode Q2, the emitter of the triode Q2 is connected to the digital ground, the base of the triode Q2 is connected to the anode through the voltage dividing resistor R2, the base of the triode Q2 is connected to the emitter of the triode Q2 through the voltage dividing resistor R3, and the emitter of the triode Q2 is connected to the anode of the voltage stabilizing source TL431 through the sampling resistor Rcs. The cathode of the diode side of the photoelectric coupler PC817 is also connected to the cathode of the voltage stabilizing source TL431, and the cathode of the voltage stabilizing source TL431 is connected with the reference electrode of the voltage stabilizing source TL431 after passing through a capacitor C3. The reference pole of the voltage-stabilizing source TL431 is connected to the first end of the load Rout, i.e., the Uout end, through the voltage-dividing resistor Rupper, and the reference pole of the voltage-stabilizing source TL431 is also connected to the second end of the load Rout through the voltage-dividing resistor Rlower.
In the example shown in fig. 2, at the output of the flyback power supply, a current loop C is added. In the current loop C, an NPN transistor diode Q2 is provided, and three resistors such as a voltage dividing resistor R2, a voltage dividing resistor R3, and a sampling resistor Rcs are provided. The sampling resistor Rcs is used for overload sampling, the voltage dividing resistor R2 and the voltage dividing resistor R3 are used for dividing voltage to control the on and off of the NPN triode Q2, when overload occurs, the NPN triode Q2 is turned on, and the current loop C replaces a voltage loop to work, so that the overload protection effect is achieved.
For the working principle of the output load overload protection circuit of the power supply shown in fig. 2, reference may be made to the following exemplary description.
When the load normally works, the voltage Ucs generated at two ends of the resistor Rcs by the current Iout of the load Rout is lower than the threshold voltage of the NPN triode Q2 by the voltage value U3 after being divided by the voltage dividing resistor R2 and the voltage dividing resistor R3, and the power supply maintains the stability of the output voltage through a voltage loop feedback network formed by the photoelectric coupler PC817 and the voltage stabilizing source TL 431. The specific realization principle is as follows:
when the actual output voltage Uout is higher than the nominal output voltage U, the voltage value Ulower of the actual output voltage Uout after voltage division through the resistor Rupper and the resistor Rlower is higher than the internal voltage reference value Uref of the voltage-stabilizing source TL431, the cathode voltage of the voltage-stabilizing source TL431 is reduced, the current If on the diode side through the photocoupler PC817 is increased, the current Ic on the transistor side through the photocoupler PC817 is increased, and the voltage Ufb is reduced. When the voltage Usns (Ip) Rsns at two ends of the primary sampling resistor Rsns of the transformer T1 is higher than the voltage Ufb, the voltage comparator outputs high level, the PWM pulse controller is reset and turned off, and the MOS tube Q1 is turned off; because the voltage Ufb decreases, the primary peak current Ip of the transformer T1, Usns/Rsns, decreases, i.e. the duty cycle of the MOS transistor Q1 decreases, the transfer energy of the transformer T1 decreases, and the secondary output voltage Uout of the transformer T1 decreases, so as to maintain the output voltage stable.
On the contrary, when the actual output voltage Uout is lower than the nominal output voltage U, the voltage value Ulower of the actual output voltage Uout after voltage division through the resistor Rupper and the resistor Rlower is lower than the internal voltage reference value Uref of the voltage stabilizing source TL431, the cathode of the voltage stabilizing source TL431 is disconnected, the current If on the diode side through the photocoupler PC817 is 0, the current Ic on the transistor side through the PC817 is 0, and the voltage Ufb is increased, so that the primary side peak current Ip of the transformer T1 is increased by us/Rsns, that is, the duty ratio of the MOS transistor is increased, the transfer energy of the transformer is increased, and the secondary side output voltage Uout is increased to maintain the output voltage stable and constant.
When the load Rout at the output end is overloaded, the current Iout passing through the load Rout is higher than the nominal output current, the voltage Ucs generated at the two ends of the resistor Rcs is increased, the voltage value U3 after voltage division by the voltage dividing resistor R2 and the voltage dividing resistor R3 is increased and is larger than the threshold voltage of the NPN triode Q2, the NPN triode Q2 is conducted and replaces a voltage ring formed by a voltage stabilizing source TL431 to work as a current ring, the current If is increased, the current Ic passing through the transistor side of the photoelectric coupler PC817 is increased, the voltage Ufb is reduced, the duty ratio of the MOS transistor is reduced, the output voltage is reduced, and the circuit is prevented from being damaged by overload of the load.
When the load Rout is overloaded or even short-circuited, the voltage loop formed by the voltage stabilizing source TL431 is short-circuited and does not work, and the NPN triode Q2 enables the power supply to act as a constant current generator. The output characteristic of the power supply can be seen in the example shown in fig. 3. When the overload is eliminated, the current Iout is reduced, the voltage U3 is lower than the threshold voltage of the NPN triode Q2, the current loop C is closed, the voltage loop starts to play a control role, and the voltage returns to the normal working voltage.
Since the processing and functions of the automobile of this embodiment are basically corresponding to the embodiment, principle and example of the device shown in fig. 1, the description of this embodiment is not given in detail, and reference may be made to the related description in the foregoing embodiment, which is not described herein again.
Through a large number of tests, the technical scheme of the invention is adopted, and the current loop is added at the output end of the vehicle-mounted power supply, so that after the fault is eliminated, the current loop of the power supply is forbidden, the protection state is removed, the normal output voltage is recovered, the power-on reset is not needed, and the protection mode is more reliable and intelligent.
According to the embodiment of the invention, the load protection method of the flyback transformer switching power supply of the electrical equipment corresponding to the automobile is also provided. The load protection method of the flyback transformer switching power supply of the automobile can be applied to the aspect of load overload or short circuit protection of the flyback transformer switching power supply (namely, the flyback transformer switching power supply) of the pure electric automobile. In load overload or short-circuit protection of a flyback power supply (i.e., a flyback transformer switching power supply) of a pure electric vehicle, the flyback transformer switching power supply may include: the power supply comprises an input power supply module (such as an input power supply A), a transformer module and a feedback control module. The feedback control module can include: the device comprises a feedback module, a voltage loop module (such as a voltage loop D), a comparison module and a control module. The input power supply module (such as an input power supply A) is connected to the primary winding of the transformer module, and the secondary winding of the transformer module is output to a load after passing through the feedback module and the voltage loop module. The secondary winding of the transformer module is fed back to the primary winding of the transformer module after passing through the feedback module, the comparison module and the control module.
In load overload or short-circuit protection of a flyback power supply (i.e., a flyback transformer switching power supply) of a pure electric vehicle, the load protection method of the flyback transformer switching power supply of the vehicle may include: through the current loop module, under the condition that the load of flyback transformer switching power supply's output is transshipped or the short circuit, replace voltage loop module work or make voltage loop module short circuit restricts flyback transformer switching power supply's output current, in order to realize right flyback transformer switching power supply's load protection, realize promptly right the overload or the short circuit protection of flyback transformer switching power supply's load.
Therefore, the current loop module is additionally arranged at the output end of the flyback transformer switching power supply, the load current can be limited, when an output load overload fault occurs, the protection circuit can be quickly and timely started and protected, the power supply fault is prevented from being expanded, the normal work of other power supplies cannot be influenced, the automobile can be safely parked, and the safety of personnel in the automobile is guaranteed.
In some embodiments, a specific process of limiting the output current of the flyback transformer switching power supply by the current loop module instead of operating or short-circuiting the voltage loop module in case of overload or short circuit of the load of the flyback transformer switching power supply can be seen in the following exemplary description.
With reference to the flowchart of fig. 4, a specific process of limiting the output current of the flyback transformer switching power supply is further described, where the specific process includes: step S110 to step S130.
At step S110, the load voltage is sampled by a first sampling module.
In step S120, the sampled load voltage is divided by the first voltage dividing module and the second voltage dividing module to obtain a divided voltage.
At step S130, by a first switch module, in case the divided voltage of the control terminal of the first switch module is greater than a threshold voltage of the first switch module:
firstly, if the load is overloaded, the first switch module is conducted and replaces a voltage stabilizing source module, the current loop module replaces a voltage loop module, the duty ratio of the second switch module is reduced, and therefore the output voltage of the flyback transformer switch power supply is controlled to be reduced. For example: when the load Rout at the output end is overloaded, the current Iout passing through the load Rout is higher than the nominal output current, the voltage Ucs generated at the two ends of the resistor Rcs is increased, the voltage value U3 after voltage division by the voltage dividing resistor R2 and the voltage dividing resistor R3 is increased and is larger than the threshold voltage of the NPN triode Q2, the NPN triode Q2 is conducted and replaces a voltage ring formed by a voltage stabilizing source TL431 to work as a current ring, the current If is increased, the current Ic passing through the transistor side of the photoelectric coupler PC817 is increased, the voltage Ufb is reduced, the duty ratio of the MOS transistor is reduced, the output voltage is reduced, and the circuit is prevented from being damaged by overload of the load.
And secondly, if the load is short-circuited, the voltage ring module is short-circuited, and the first switch module is switched on, so that the flyback transformer switching power supply is used as a constant current generator. For example: when the load Rout is overloaded or even short-circuited, the voltage loop formed by the voltage stabilizing source TL431 is short-circuited and does not work, and the NPN triode Q2 enables the power supply to act as a constant current generator.
Therefore, a current loop is formed by adding devices such as NPN transistors and the like at the output end of the vehicle-mounted power supply, so that the problems that when abnormal overload or even short circuit occurs to a load, power supply faults are not enlarged, normal work of other power supplies is not influenced, and safe parking is not influenced, so that normal work of other functional modules in a vehicle is ensured, the vehicle can be parked safely, and safety of personnel in the vehicle is guaranteed.
In some embodiments, it can further include: the control method for controlling the flyback transformer switching power supply to normally supply power under the condition that the load is normal, that is, the load is not overloaded and short-circuited, or under the condition that the fault of the overload or short-circuit of the load is relieved can specifically include: through the current loop module, under the condition that the load of the output end of the flyback transformer switching power supply is normal or the condition that the load overload or short circuit of the output end of the flyback transformer switching power supply is relieved, the current loop module is forbidden, and the voltage loop module works, so that the flyback transformer switching power supply normally supplies power to the load.
Specifically, under the condition that the load is normal, namely the load is not overloaded and short-circuited, the current loop module is forbidden, and the voltage loop module works normally, so that the flyback transformer switching power supply supplies power to the load normally; and under the condition that the overload or short circuit condition of the load at the output end of the flyback transformer switching power supply is relieved, the current loop module is forbidden, and the voltage loop module is recovered to work so as to relieve the load protection of the flyback transformer switching power supply and recover the flyback transformer switching power supply to normally supply power to the load.
Therefore, the current loop module is additionally arranged at the output end of the flyback transformer switching power supply, so that after the fault is eliminated, the power supply can automatically remove the protection state and recover the normal output voltage.
In some embodiments, the specific process of enabling the current loop module to be disabled and enabling the voltage loop module to operate under the condition that the load at the output end of the flyback transformer switching power supply is normal or under the condition that the load at the output end of the flyback transformer switching power supply is overloaded or short-circuited through the current loop module can include the following exemplary descriptions.
The following further describes a specific process of disabling the current loop module in combination with a schematic flow diagram of an embodiment of disabling the current loop module in the method of the present invention shown in fig. 5, and the specific process can include: step S210 to step S230.
In step S210, the load voltage is sampled by the first sampling module.
Step S220, the sampled load voltage is divided by the first voltage dividing module and the second voltage dividing module to obtain a divided voltage.
Step S230, by using a first switch module, under the condition that the divided voltage at the control end of the first switch module is less than or equal to the threshold voltage of the first switch module, turning off the first switch module to close the current loop module and operate the voltage loop module.
For example: when the overload is eliminated, the current Iout is reduced, the voltage U3 is lower than the threshold voltage of the NPN triode Q2, the current loop C is closed, the voltage loop starts to play a control role, and the voltage returns to the normal working voltage.
When the actual output voltage Uout is higher than the nominal output voltage U, the voltage value Ulower of the actual output voltage Uout after voltage division through the resistor Rupper and the resistor Rlower is higher than the internal voltage reference value Uref of the voltage-stabilizing source TL431, the cathode voltage of the voltage-stabilizing source TL431 is reduced, the current If on the diode side through the photocoupler PC817 is increased, the current Ic on the transistor side through the photocoupler PC817 is increased, and the voltage Ufb is reduced. When the voltage Usns (Ip) Rsns at two ends of the primary sampling resistor Rsns of the transformer T1 is higher than the voltage Ufb, the voltage comparator outputs high level, the PWM pulse controller is reset and turned off, and the MOS tube Q1 is turned off; because the voltage Ufb decreases, the primary peak current Ip of the transformer T1, Usns/Rsns, decreases, i.e. the duty cycle of the MOS transistor Q1 decreases, the transfer energy of the transformer T1 decreases, and the secondary output voltage Uout of the transformer T1 decreases, so as to maintain the output voltage stable.
On the contrary, when the actual output voltage Uout is lower than the nominal output voltage U, the voltage value Ulower of the actual output voltage Uout after voltage division through the resistor Rupper and the resistor Rlower is lower than the internal voltage reference value Uref of the voltage stabilizing source TL431, the cathode of the voltage stabilizing source TL431 is disconnected, the current If on the diode side through the photocoupler PC817 is 0, the current Ic on the transistor side through the PC817 is 0, and the voltage Ufb is increased, so that the primary side peak current Ip of the transformer T1 is increased by us/Rsns, that is, the duty ratio of the MOS transistor is increased, the transfer energy of the transformer is increased, and the secondary side output voltage Uout is increased to maintain the output voltage stable and constant.
Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the automobile, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment, which is not described herein.
Through a large number of tests, the technical scheme of the embodiment is adopted, and the current ring is added at the output end of the flyback power supply, so that when abnormal overload or even short circuit occurs to a load, the output current can be limited, the load is immediately protected, the power supply fault is prevented from being expanded, the normal work of other power supplies is prevented from being influenced, the normal work of other functional modules of the automobile is prevented from being influenced, the automobile can be safely parked, and the safety of personnel in the automobile is guaranteed.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (12)

1. A load protection device of a flyback transformer switching power supply is characterized in that the flyback transformer switching power supply comprises: the system comprises an input power module, a transformer module and a feedback control module; the feedback control module includes: the device comprises a feedback module, a voltage loop module, a comparison module and a control module;
the load protection device of the flyback transformer switching power supply comprises: a current loop module;
the current loop module is arranged between the feedback module and the voltage loop module and is configured to limit the output current of the flyback transformer switching power supply under the condition that the load of the flyback transformer switching power supply is overloaded or short-circuited, so that the load protection of the flyback transformer switching power supply is realized.
2. The load protection device of a flyback transformer switching power supply of claim 1, further comprising:
the current loop module is further configured to disable the current loop module and enable the voltage loop module to operate under the condition that the load of the flyback transformer switching power supply is normal or the condition that the load overload or short circuit of the flyback transformer switching power supply is relieved, so that the flyback transformer switching power supply normally supplies power to the load.
3. The load protection device of the flyback transformer switching power supply of claim 2, wherein the feedback module comprises: an optocoupler module; the current loop module includes: the sampling device comprises a first switch module, a first voltage division module, a second voltage division module and a first sampling module; wherein the content of the first and second substances,
the first switch end of the first switch module is connected to a cathode of a diode side in the optocoupler module and is also connected to the voltage ring module; the control end of the first switch module is connected to the first end of the first sampling module after passing through the first voltage division module, and is also connected to the second end of the first sampling module after passing through the second voltage division module; the first end of the first sampling module is connected to a load, and the second end of the first sampling module is connected to the second switch end of the first switch module.
4. The load protection device of the flyback transformer switching power supply of claim 3, wherein the voltage loop module comprises: the voltage stabilizing source module, the filtering module, the third voltage dividing module and the fourth voltage dividing module; wherein the content of the first and second substances,
the cathode of the voltage stabilizing source module is connected to the cathode of the diode side in the optical coupling module and is also connected to the reference pole of the voltage stabilizing source module after passing through the filtering module; the third voltage division module and the fourth voltage division module are connected in series and then connected in parallel with a load, and the common end of the third voltage division module and the common end of the fourth voltage division module are connected to the reference electrode of the voltage stabilizing source module; and the anode of the voltage-stabilizing source module is connected to the first end of the first sampling module.
5. The load protection device of the flyback transformer switching power supply as in claim 3 or 4, wherein the control module comprises: the pulse control module, the second switch module and the second sampling module; wherein the content of the first and second substances,
the non-inverting input end of the comparison module is connected to the second sampling module and is also connected to the second switch end of the second switch module; the inverting input end of the comparison module is connected to a collector electrode on the transistor side in the optical coupling module; the output end of the comparison module is connected to the control end of the second switch module after passing through the pulse control module;
and the first switching end of the second switching tube is connected to the primary winding of the transformer module.
6. The load protection device of the flyback transformer switching power supply of claim 5, wherein the current loop module limiting the output current of the flyback transformer switching power supply comprises:
sampling, by the first sampling module, a load voltage;
dividing the sampled load voltage through the first voltage division module and the second voltage division module to obtain divided voltage;
by the first switch module, in the case that the divided voltage of the control terminal of the first switch module is greater than a threshold voltage of the first switch module:
if the load is overloaded, the first switch module is conducted and replaces the voltage stabilizing source module, so that the current loop module replaces the voltage loop module to work, the duty ratio of the control end of the second switch module is reduced, and the output voltage of the switching power supply of the flyback transformer is controlled to be reduced;
and if the load is short-circuited, the voltage loop module is short-circuited, and the first switch module is switched on, so that the flyback transformer switching power supply is used as a constant current generator.
7. The load protection device of a flyback transformer switching power supply of claim 5, wherein the current loop module, causing the current loop module itself to be disabled and causing the voltage loop module to operate, comprises:
sampling, by the first sampling module, a load voltage;
dividing the sampled load voltage through the first voltage division module and the second voltage division module to obtain divided voltage;
through the first switch module, under the condition that the divided voltage at the control end of the first switch module is less than or equal to the threshold voltage of the first switch module, the first switch module is turned off, so that the current loop module is turned off, and the voltage loop module is enabled to work.
8. An electrical device, comprising: the load protection device of the flyback transformer switching power supply of any of claims 1-7.
9. A load protection method of a flyback transformer switching power supply of an automobile according to claim 8, comprising:
through the current loop module, under the condition that the load of the flyback transformer switching power supply is overloaded or short-circuited, the output current of the flyback transformer switching power supply is limited, so that the load protection of the flyback transformer switching power supply is realized.
10. The method of claim 9, further comprising:
through the current loop module, under the condition that the load of the flyback transformer switching power supply is normal or the condition that the load overload or short circuit of the flyback transformer switching power supply is relieved, the current loop module is forbidden, and the voltage loop module works, so that the flyback transformer switching power supply normally supplies power to the load.
11. The method of claim 9, wherein limiting the output current of the flyback transformer switching power supply via a current loop module comprises:
sampling the load voltage through a first sampling module;
dividing the sampled load voltage through a first voltage division module and a second voltage division module to obtain divided voltage;
by a first switch module, in the case that the divided voltage at the control terminal of the first switch module is greater than a threshold voltage of the first switch module:
if the load is overloaded, the first switch module is conducted and replaces a voltage stabilizing source module, the current loop module replaces a voltage loop module, the duty ratio of the second switch module is reduced, and therefore the output voltage of the flyback transformer switching power supply is controlled to be reduced;
and if the load is short-circuited, the voltage loop module is short-circuited, and the first switch module is switched on, so that the flyback transformer switching power supply is used as a constant current generator.
12. The method of claim 10, wherein the current loop module is disabled and the voltage loop module is enabled to operate by the current loop module, the method comprising:
sampling the load voltage through a first sampling module;
dividing the sampled load voltage through a first voltage division module and a second voltage division module to obtain divided voltage;
through the first switch module, under the condition that the divided voltage at the control end of the first switch module is less than or equal to the threshold voltage of the first switch module, the first switch module is turned off, so that the current loop module is turned off, and the voltage loop module is operated.
CN202010885927.3A 2020-08-28 2020-08-28 Load protection device and method of flyback transformer switching power supply and electrical equipment Pending CN112072903A (en)

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CN202010885927.3A CN112072903A (en) 2020-08-28 2020-08-28 Load protection device and method of flyback transformer switching power supply and electrical equipment

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112752374A (en) * 2021-01-29 2021-05-04 广东东菱电源科技有限公司 Potentiometer type constant power circuit, driving power supply and power supply constant power adjusting method

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101442260A (en) * 2007-11-23 2009-05-27 技领半导体(上海)有限公司 Secondary constant-current constant-voltage controller chip and converter thereof
CN101951135A (en) * 2010-08-26 2011-01-19 奇瑞汽车股份有限公司 Flyback switching power supply and over-current protection method thereof
CN203522512U (en) * 2013-11-01 2014-04-02 广州市爱浦电子科技有限公司 New type flyback converter constant-voltage and constant-current control circuit
CN203536942U (en) * 2013-11-01 2014-04-09 广州市爱浦电子科技有限公司 A novel ring choke converter output overvoltage protection circuit
CN105391305A (en) * 2015-12-29 2016-03-09 杭州茂力半导体技术有限公司 Insulation-type switch converter as well as secondary control circuit and control method thereof
JP2017175753A (en) * 2016-03-23 2017-09-28 ローム株式会社 Insulation synchronous rectification type dc/dc converter, synchronous rectification circuit, power supply adapter, electronic equipment, and control method
CN206595898U (en) * 2017-03-24 2017-10-27 无锡硅动力微电子股份有限公司 Secondary inverse-excitation type switch power-supply based on SP6650

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101442260A (en) * 2007-11-23 2009-05-27 技领半导体(上海)有限公司 Secondary constant-current constant-voltage controller chip and converter thereof
CN101951135A (en) * 2010-08-26 2011-01-19 奇瑞汽车股份有限公司 Flyback switching power supply and over-current protection method thereof
CN203522512U (en) * 2013-11-01 2014-04-02 广州市爱浦电子科技有限公司 New type flyback converter constant-voltage and constant-current control circuit
CN203536942U (en) * 2013-11-01 2014-04-09 广州市爱浦电子科技有限公司 A novel ring choke converter output overvoltage protection circuit
CN105391305A (en) * 2015-12-29 2016-03-09 杭州茂力半导体技术有限公司 Insulation-type switch converter as well as secondary control circuit and control method thereof
JP2017175753A (en) * 2016-03-23 2017-09-28 ローム株式会社 Insulation synchronous rectification type dc/dc converter, synchronous rectification circuit, power supply adapter, electronic equipment, and control method
CN206595898U (en) * 2017-03-24 2017-10-27 无锡硅动力微电子股份有限公司 Secondary inverse-excitation type switch power-supply based on SP6650

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112752374A (en) * 2021-01-29 2021-05-04 广东东菱电源科技有限公司 Potentiometer type constant power circuit, driving power supply and power supply constant power adjusting method
CN112752374B (en) * 2021-01-29 2024-04-09 广东东菱电源科技有限公司 Potentiometer type constant power circuit, driving power supply and power supply constant power regulating method

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