CN117294117B - Primary side current detection circuit and detection method for multi-winding series high-voltage flyback power supply - Google Patents
Primary side current detection circuit and detection method for multi-winding series high-voltage flyback power supply Download PDFInfo
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- CN117294117B CN117294117B CN202311585645.1A CN202311585645A CN117294117B CN 117294117 B CN117294117 B CN 117294117B CN 202311585645 A CN202311585645 A CN 202311585645A CN 117294117 B CN117294117 B CN 117294117B
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0009—Devices or circuits for detecting current in a converter
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
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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
- H02H7/1213—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 for DC-DC 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Dc-Dc Converters (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention relates to the technical field of power supply detection protection, in particular to a primary side current detection circuit and a detection method of a multi-winding serial high-voltage flyback power supply, wherein the detection protection circuit comprises a multi-winding flyback transformer, a two-in-one current transformer and a detection superposition circuit; the multi-winding flyback transformer comprises a first primary winding, a second primary winding and a third primary winding, wherein the first primary winding, the second primary winding and the third primary winding are respectively connected with a switch MOS tube in series to form a first series circuit, a second series circuit and a third series circuit, and voltage dividing capacitors are respectively connected in parallel on the first series circuit, the second series circuit and the third series circuit to respectively form a first primary winding power loop, a second primary winding power loop and a third primary winding power loop, and the first primary winding, the second primary winding and the third primary winding are respectively connected with a flyback power supply output end; the invention can realize the accurate detection of the current of each primary winding of the multi-winding flyback power supply.
Description
Technical Field
The invention relates to the technical field of power supply detection protection, in particular to a primary side current detection circuit and a primary side current detection method of a multi-winding serial high-voltage flyback power supply.
Background
Along with the high-speed development of energy storage technology, the voltage of a direct current bus is higher and higher, and can reach 1500V, and as the voltage of the direct current bus is higher, the voltage withstand value of a switching diode is improved, and the risk of breakdown of the switching diode is higher, so that the primary side switching diode of an auxiliary power supply of equipment is very difficult to select, and the voltage stress of a single switching diode is reduced by adopting a primary side multi-winding series connection mode.
In the prior art, the high-voltage flyback power supply adopts a multi-winding series connection mode, so that the current detection and summation of each winding are difficult to realize.
Therefore, a primary side current detection circuit of the multi-winding serial high-voltage flyback power supply is required to be designed, and accurate detection of current of each winding can be realized.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a primary side current detection circuit of a high-voltage flyback power supply.
The invention provides a primary side current detection circuit of a high-voltage flyback power supply, which comprises a multi-winding flyback transformer, a two-in-one current transformer and a detection superposition circuit, wherein the detection superposition circuit is connected with the primary side current detection circuit;
the multi-winding flyback transformer comprises a first primary winding, a second primary winding and a third primary winding, wherein the first primary winding is connected with the switch MOS tube in series to form a first series circuit, and a voltage dividing capacitor is connected in parallel on the first series circuit to form a first primary winding power loop; the second primary winding is connected with the switch MOS tube in series to form a second series circuit, and the voltage dividing capacitor is connected in parallel on the second series circuit to form a second primary winding power loop; the third primary winding is connected with the switch MOS tube in series to form a third series circuit, a voltage dividing capacitor is connected in parallel on the third series circuit to form a third primary winding power loop, and the first primary winding, the second primary winding and the third primary winding are respectively connected with the output end of the flyback power supply;
the two-in-one current transformer comprises two fourth primary windings and a secondary winding, wherein the two fourth primary windings are respectively connected in series with a first primary winding in the first primary winding power loop and a second primary winding in the second primary winding power loop and are used for obtaining the current sum of the two fourth primary windings; the output ends of the two fourth primary windings are connected with one end of the secondary winding and are used for sensing the sum of currents of the two fourth primary windings and outputting currents, the other end of the secondary winding is connected with the input end of the detection superposition circuit, the input end of the detection superposition circuit is also connected with the power loop of the third primary winding and is used for sending current signals output by the two-in-one current transformer and current signals output by the third primary winding into the detection superposition circuit to be converted into voltage signals;
the two-in-one current transformer is used for inducing the current sum of the two fourth primary windings to the secondary winding;
and the output end of the detection superposition circuit is connected with the current detection end of the control IC.
Further, the number of turns of the two fourth primary windings is the same.
Further, the detection superposition circuit comprises a first current detection resistor and a second current detection resistor;
one end of the first current detection resistor is connected with the current detection end of the control IC, the other end of the first current detection resistor is connected with one end of the second current detection resistor in series, the second current detection resistor is connected in the power loop of the third primary winding in series, and the other end of the second current detection resistor is connected with the primary reference ground and is used for converting a current signal of the third primary winding into a voltage signal through the second current detection resistor;
the detection superposition circuit is used for superposing the voltage signal converted from the output current signal of the two-in-one current transformer and the voltage signal converted from the output current signal of the third primary winding and outputting the voltage signal to the current detection end of the control IC.
Further, the first current detection resistor, the second current detection resistor and the two-in-one current transformer have the following parameter relation: the turns ratio of the two fourth primary windings to the secondary windings in the two-in-one current transformer is 1:1:n, and the n value is 200-500; the resistance value of the first current detection resistor is n times of that of the second current detection resistor.
Further, the detection superposition circuit further comprises a first diode and a second diode;
the first diode and the second diode which are connected in series are connected in parallel to the first current detection resistor, and are used for converting the sum of currents output by the two-in-one current transformer into voltage signals through detecting the first diode of the superposition circuit;
the secondary winding homonymous end of the two-in-one current transformer is connected with the first diode anode, the first diode cathode is connected with the first current detection resistor and used for blocking voltage signals of the first current detection resistor and the second current detection resistor, the second diode anode is connected with the first current detection resistor, the second diode cathode is connected with the secondary winding homonymous end of the two-in-one current transformer and used for blocking current signals of the first current detection resistor, and the midpoints of the first current detection resistor and the second current detection resistor which are connected in series are connected with the secondary winding heteronymous end of the two-in-one current transformer.
A primary side current detection method of a multi-winding series high-voltage flyback power supply comprises the following steps:
s1, acquiring currents of a first primary winding and a second primary winding of a flyback power supply;
s2, the current sum of the two fourth primary windings is sensed to the secondary winding through a two-in-one current transformer;
s31, converting a current signal output by the two-in-one current transformer into a voltage signal through a detection superposition circuit;
s32, converting a current signal of the third primary winding into a voltage signal through a second current detection resistor;
s4, superposing the voltage signals converted from the current signals output by the first primary winding and the second primary winding and the voltage signals converted from the current signals output by the third primary winding through a detection superposition circuit, and sending the voltage signals to a control IC current detection end;
compared with the prior art, the invention has the beneficial effects that:
the detection protection circuit can realize accurate detection of the current of each primary winding of the multi-winding flyback power supply by arranging the winding flyback transformer, the two-in-one current transformer, the detection superposition circuit and the control IC, sums the current of each winding, sends the summed current into the control IC for current control, and performs overcurrent protection on each winding.
Drawings
The following drawings are illustrative of the invention and are not intended to limit the scope of the invention, in which:
FIG. 1 is a schematic diagram of a current detection protection circuit according to the present application;
FIG. 2 is a schematic flow chart of the current detection protection method of the present application;
in the figure: the current transformer comprises a 1-first primary winding, a 2-second primary winding, a 3-third primary winding, a 4-fourth primary winding, a T2-two-in-one current transformer, a D1-first diode, a D2-second diode, a Rs 1-first current detection resistor, a Rs 2-second current detection resistor, a T1-multi-winding flyback transformer and a T3-detection superposition circuit.
Detailed Description
The present invention will be further described in detail with reference to the following specific examples, which are given by way of illustration, in order to make the objects, technical solutions, design methods and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1-2, the invention provides a primary side current detection circuit of a multi-winding serial high-voltage flyback power supply, which comprises a multi-winding flyback transformer T1, a two-in-one current transformer T2 and a detection superposition circuit T3;
the multi-winding flyback transformer T1 comprises a first primary winding 1, a second primary winding 2 and a third primary winding 3, wherein the first primary winding 1 and a switch MOS tube are connected in series to form a first series circuit, and a voltage dividing capacitor is connected in parallel on the first series circuit to form a first primary winding power loop; the second primary winding 2 and the switch MOS tube are connected in series to form a second series circuit, and a voltage dividing capacitor is connected in parallel on the second series circuit to form a second primary winding power loop; the third primary winding 3 is connected with the switch MOS tube in series to form a third series circuit, a voltage dividing capacitor is connected in parallel on the third series circuit to form a third primary winding power loop, and the first primary winding 1, the second primary winding 2 and the third primary winding 3 are respectively connected with the output end of the flyback power supply;
wherein, the English whole name of the switch MOS tube is MOSFET (Metal Oxide Semiconductor Field Effect Transistor);
the two-in-one current transformer T2 comprises two fourth primary windings 4 and a secondary winding, wherein the two fourth primary windings 4 are respectively connected in series with a first primary winding 1 in a first primary winding power loop and a second primary winding 2 in a second primary winding power loop, and are used for obtaining the current sum of the two fourth primary windings 4; the output ends of the two fourth primary windings 4 are connected with one end of a secondary winding, and are used for sensing the sum of currents of the two fourth primary windings 4 and outputting currents, the other end of the secondary winding is connected with the input end of the detection superposition circuit T3, the input end of the detection superposition circuit T3 is also connected with a third primary winding power loop, and the output current signals of the two-in-one current transformer T2 and the output current signals of the third primary winding 3 are sent into the detection superposition circuit T3 to be converted into voltage signals;
the two-in-one current transformer T2 is used for inducing the current sum of the two fourth primary windings 4 to the secondary windings through the two-in-one current transformer T2;
the output end of the detection superposition circuit T3 is connected with the current detection end of the control IC; IC is an integrated circuit (integrated circuit abbreviated IC);
further, the number of turns of the two fourth primary windings 4 is the same;
further, the detection superimposing circuit T3 includes a first current detection resistor Rs1 and a second current detection resistor Rs2;
one end of the first current detection resistor Rs1 is connected with the current detection end of the control IC, the other end of the first current detection resistor Rs1 is connected with one end of the second current detection resistor Rs2 in series, the second current detection resistor Rs2 is connected in series in the power loop of the third primary winding, and the other end of the second current detection resistor Rs2 is connected with the primary reference ground and is used for converting a current signal of the third primary winding into a voltage signal through the second current detection resistor Rs2;
the detection superposition circuit T3 is used for superposing and outputting the voltage converted by the output current of the two-in-one current transformer T2 and the voltage converted by the output current of the third primary winding 3 to a control IC current detection end;
further, the first current detection resistor Rs1, the second current detection resistor Rs2 and the two-in-one current transformer have the following parameter relationship: the turns ratio of the two fourth primary windings 4 to the secondary windings in the two-in-one current transformer is 1:1:n, and the n value is 200-500; the resistance value of the first current detection resistor Rs1 is n times of that of the second current detection resistor Rs2;
the detection superposition circuit T3 further comprises a first diode D1 and a second diode D2;
the first diode D1 and the second diode D2 connected in series are connected in parallel to the first current detection resistor Rs1, and are used for converting the sum of currents output by the two-in-one current transformer into voltage signals through detecting the first diode D1 of the superposition circuit T3;
the anode of the first diode D1 is connected to the same-name end of the secondary winding of the two-in-one current transformer, the cathode of the first diode D1 is connected to the first current detection resistor Rs1 and used for blocking voltage signals of the first current detection resistor Rs1 and the second current detection resistor Rs2, the anode of the second diode D2 is connected to the first current detection resistor Rs1, the cathode of the second diode D2 is connected to the same-name end of the secondary winding of the two-in-one current transformer and used for blocking current signals of the first current detection resistor Rs1, and the midpoints of the first current detection resistor Rs1 and the second current detection resistor Rs2 which are connected in series are connected to the different-name end of the secondary winding of the two-in-one current transformer;
when the flyback power source primary side switch diode is turned on, the currents of the first primary side winding 1, the second primary side winding 2 and the third primary side winding 3 are gradually increased; the currents of the first primary winding 1 and the second primary winding 2 respectively flow through two fourth primary windings 4 of the primary side of the two-in-one current transformer T2, magnetic flux Is generated in a magnetic core of the two-in-one current transformer T2, the magnetic flux generated by the two fourth primary windings 4 Is overlapped in the magnetic core, a detection current Is1 Is induced by a secondary winding of the two-in-one current transformer, the current Is1 and the two primary windings are in proportional relation, the ratio Is the primary and secondary turns ratio of the two-in-one current transformer T2, and the currents of the two fourth primary windings 4 of the two-in-one current transformer T2 are obtained according to the relation between the primary turns and the resistance of the two-in-one current transformer T2, so that the current of the primary winding of the flyback power supply Is obtained, and the accurate detection of the current of each primary winding of the multi-winding flyback power supply Is realized;
since the second diode D2 in the detection superimposing circuit T3 Is present, the current Is1 can only generate the voltage Vs1 across the resistor Rs1 through the first diode D1, since the second current detecting resistor Rs2 Is much smaller than the first current detecting resistor Rs1, the voltage across the resistor Rs2 of the current Is1 Is ignored, and the current of the third primary winding 3 directly generates the voltage Vs2 through the second current detecting resistor Rs2 in the detection superimposing circuit T3, since the first current detecting resistor Rs1 Is much larger than the second current detecting resistor Rs2, the current flowing across the first current detecting resistor Rs1 Is ignored. At this time, the voltage at the current detection end of the control IC is the voltage Vs1 plus the voltage Vs2;
the relation among the resistance value of the first current detection resistor Rs1, the resistance value of the second current detection resistor Rs2 and the parameters of the two-in-one current transformer T2 in the detection superposition circuit T3 is as follows: the primary and secondary side turn ratio of the two-in-one current transformer T2 is 1:1:n, and n is adjustable; the resistance value of the first current detection resistor Rs1 is n times of that of the second current detection resistor Rs2; the value of n is 200-500, the specific value of the second current detection resistor Rs2 is designed by combining flyback main power, and the specific value is smaller than 0.5 omega;
when the flyback power source primary side switch diode is turned off, the currents of the first primary side winding 1, the second primary side winding 2 and the third primary side winding 3 become zero, the two-in-one current transformer T2 realizes magnetic reset through the follow current of the second diode D2, and the first diode D1 blocks negative voltage from being applied to the current detection end of the control IC.
The resistance value of the second current detection resistor Rs2 is smaller than that of the first current detection resistor Rs1;
the control IC is used for controlling the flyback power supply by detecting a current signal output by the superposition circuit T3;
the control IC comprises a comparison unit, and a detection superposition circuit T3 voltage signal output end is connected with the comparison unit and is used for comparing with a reference voltage threshold in the control IC to judge whether to drive the switching diode;
it should be noted that, the final current signal (converted into voltage signal) of the detection and superposition circuit T3 is sent to the control IC, and compared with the reference voltage threshold in the control IC, if the current signal is greater than the reference voltage threshold, the control IC does not output the switching diode drive, so as to implement the overcurrent protection function.
The primary side current detection method of the multi-winding high-voltage flyback power supply comprises the following steps of:
s1, acquiring currents of a first primary winding 1 and a second primary winding 2 of a flyback power supply;
s2, the current sum of the two fourth primary windings 4 is sensed to the secondary windings through a two-in-one current transformer T2;
s31, converting a current signal output by the two-in-one current transformer T2 into a voltage signal through the detection superposition circuit T3;
s32, converting a current signal of the third primary winding 3 into a voltage signal through a second current detection resistor Rs2;
s4, the voltage signals converted from the current signals output by the first primary winding 1 and the second primary winding 2 are overlapped with the voltage signals converted from the current signals output by the third primary winding 3 through the detection overlapping circuit T3, and the voltage signals are sent to the control IC.
It is worth to say that, the primary side current detection circuit of the high-voltage flyback power supply is characterized in that through arranging a multi-winding flyback transformer T1, a two-in-one current transformer T2, a detection superposition circuit T3 and a control IC, the output current of the two-in-one current transformer T2 and the current of a third primary side winding 3 are converted into voltage signals and are superposed and output (converted into voltage signals) and sent into the control IC to perform current control, the output voltage of the detection superposition circuit T3 is compared with a reference voltage threshold in the control IC, and if the output voltage is larger than the reference voltage threshold, the control IC does not output a switching diode drive, so that the overcurrent protection function of each primary side winding is realized;
the secondary winding of the two-in-one current transformer T2 Is used for inducing to generate a detection current Is1, the two primary currents and the proportional relation, the proportion Is the primary-secondary turns ratio of the two-in-one current transformer T2, and the current of the fourth primary winding 4 of the two-in-one current transformer T2 Is obtained according to the relation between the primary turns and the resistance of the two-in-one current transformer T2, so that the current of the primary winding of the flyback power supply Is obtained.
Detection principle: the primary side current detection circuit of the multi-winding serial high-voltage flyback power supply accurately detects the current of each primary side winding of the multi-winding flyback power supply:
the current of the first primary winding 1, the second primary winding 2 and the third primary winding 3 of the multi-winding flyback transformer T1 in a normal working state is equal, and the current of each winding is set to be IP; the primary-secondary side turn ratio of the two-in-one current transformer T2 is 1:n;
the current of the first primary winding 1 and the second primary winding 2 of the multi-winding flyback transformer T1 flows into the primary side of the two-in-one current transformer T2 in parallel, the current flowing through the primary side of the two-in-one current transformer T2 is 2 xIP, the current induced at the secondary side of the two-in-one current transformer T2 is 2 xIP/n according to the ampere-turn conservation principle, the current represents the sum of the current of the first primary winding 1 and the second primary winding 2 of the multi-winding flyback transformer T1 divided by n times, and due to the reverse blocking effect of the first diode D1 and the second diode D2, the current can only flow through the first current detection resistor Rs1 through the first diode D1;
generating a voltage u1=2×r1×ip/n across the first current sense resistor Rs1, the voltage representing the sum of currents of the first primary winding 1 and the second primary winding 2 of the flyback transformer;
the current of the third primary winding 3 of the multi-winding flyback transformer T1 flows through the second current detection resistor Rs2, and the generated voltage is set to be u2=r2×ip, and the voltage represents the current of the third primary winding 3 of the multi-winding flyback transformer T1;
by setting the resistance value of the first current detection resistor Rs1 such that the first current detection resistor Rs 1=n×r2, the voltage of the sum of currents of the first primary winding 1 and the second primary winding 2 representing the multi-winding flyback transformer T1:
U1=2×n×Rs2×IP/n=2×Rs2×IP；
in addition, since the first current detection resistor Rs1 is connected in series with the second current detection resistor Rs2, the voltage signal representing the current sum of the first primary winding 1, the second primary winding 2 and the third primary winding 3 is u3=u1+u2=3×r2×ip;
the current ip=u3/(3×r2) of each of the first primary winding 1, the second primary winding 2, and the third primary winding 3 is known, so that the voltage value of the voltage signal U3 of the sum of the currents of the first primary winding 1, the second primary winding 2, and the third primary winding 3 is known, and the resistance value of the second current detection resistor Rs2 is known, so that the current IP of each winding can be obtained.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (4)
1. The primary side current detection circuit of the multi-winding series high-voltage flyback power supply is characterized by comprising a multi-winding flyback transformer, a two-in-one current transformer and a detection superposition circuit;
the multi-winding flyback transformer comprises a first primary winding, a second primary winding and a third primary winding, wherein the first primary winding is connected with the switch MOS tube in series to form a first series circuit, and a voltage dividing capacitor is connected in parallel on the first series circuit to form a first primary winding power loop; the second primary winding is connected with the switch MOS tube in series to form a second series circuit, and the voltage dividing capacitor is connected in parallel on the second series circuit to form a second primary winding power loop; the third primary winding is connected with the switch MOS tube in series to form a third series circuit, a voltage dividing capacitor is connected in parallel on the third series circuit to form a third primary winding power loop, and the first primary winding, the second primary winding and the third primary winding are respectively connected with the output end of the flyback power supply;
the two-in-one current transformer comprises two fourth primary windings and a secondary winding, wherein the two fourth primary windings are respectively connected in series with a first primary winding in the first primary winding power loop and a second primary winding in the second primary winding power loop and are used for obtaining the current sum of the two fourth primary windings; the output ends of the two fourth primary windings are connected with one end of the secondary winding and are used for sensing the sum of currents of the two fourth primary windings and outputting currents, the other end of the secondary winding is connected with the input end of the detection superposition circuit, the input end of the detection superposition circuit is also connected with the power loop of the third primary winding and is used for sending current signals output by the two-in-one current transformer and current signals output by the third primary winding into the detection superposition circuit to be converted into voltage signals;
the two-in-one current transformer is used for inducing the current sum of the two fourth primary windings to the secondary winding;
the output end of the detection superposition circuit is connected with the current detection end of the control IC;
the detection superposition circuit comprises a first current detection resistor and a second current detection resistor;
one end of the first current detection resistor is connected with the current detection end of the control IC, the other end of the first current detection resistor is connected with one end of the second current detection resistor in series, the second current detection resistor is connected in the power loop of the third primary winding in series, and the other end of the second current detection resistor is connected with the primary reference ground and is used for converting a current signal of the third primary winding into a voltage signal through the second current detection resistor;
the detection superposition circuit further comprises a first diode and a second diode;
the first diode and the second diode which are connected in series are connected in parallel to the first current detection resistor, and are used for converting the sum of currents output by the two-in-one current transformer into voltage signals through detecting the first diode of the superposition circuit;
the first diode anode is connected to the homonymous end of the secondary winding of the two-in-one current transformer, the first diode cathode is connected to the first current detection resistor and used for blocking voltage signals of the first current detection resistor and the second current detection resistor, the second diode anode is connected to the first current detection resistor, the second diode cathode is connected to the homonymous end of the secondary winding of the two-in-one current transformer and used for blocking current signals of the first current detection resistor, and midpoints of the first current detection resistor and the second current detection resistor which are connected in series are connected to the heteronymous end of the secondary winding of the two-in-one current transformer;
the detection superposition circuit is used for superposing the voltage signal converted from the output current signal of the two-in-one current transformer and the voltage signal converted from the output current signal of the third primary winding and outputting the voltage signal to the current detection end of the control IC.
2. The primary current detection circuit of a multi-winding series high-voltage flyback power supply of claim 1, wherein,
the number of turns of the two fourth primary windings is the same.
3. The primary current detection circuit of a multi-winding series high-voltage flyback power supply of claim 1, wherein,
the first current detection resistor, the second current detection resistor and the two-in-one current transformer have the parameter relation: the turns ratio of the two fourth primary windings to the secondary windings in the two-in-one current transformer is 1:1:n, and the n value is 200-500; the resistance value of the first current detection resistor is n times of that of the second current detection resistor.
4. A method for detecting the primary side current of a multi-winding serial high-voltage flyback power supply, which is characterized by using any one of the multi-winding serial high-voltage flyback power supply primary side current detection circuits as claimed in claims 1-3, and comprising the following steps:
s1, acquiring currents of a first primary winding and a second primary winding of a flyback power supply;
s2, the current sum of the two fourth primary windings is sensed to the secondary winding through a two-in-one current transformer;
s31, converting a current signal output by the two-in-one current transformer into a voltage signal through a detection superposition circuit;
s32, converting a current signal of the third primary winding into a voltage signal through a second current detection resistor;
s4, superposing the voltage signals converted from the current signals output by the first primary winding and the second primary winding and the voltage signals converted from the current signals output by the third primary winding through a detection superposition circuit, and sending the voltage signals to a control IC current detection end.
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|---|---|---|---|---|
| CN105517650A (en) * | 2014-08-01 | 2016-04-20 | 广州市浦来能源科技有限公司 | Fly-back dc/ac conversion circuit with plurality of windings |
| WO2019001217A1 (en) * | 2017-06-30 | 2019-01-03 | 广州金升阳科技有限公司 | Active clamping flyback switching power supply circuit |
| CN111969858A (en) * | 2020-08-25 | 2020-11-20 | 特变电工西安柔性输配电有限公司 | High-order energy-taking power circuit and control method thereof |
| WO2022033239A1 (en) * | 2020-08-10 | 2022-02-17 | 广州金升阳科技有限公司 | Current detection circuit, converter, and current detection method for converter |
| CN114336911A (en) * | 2022-02-16 | 2022-04-12 | 北京燕开新源科技有限公司 | Equalizing charge circuit for series batteries |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105517650A (en) * | 2014-08-01 | 2016-04-20 | 广州市浦来能源科技有限公司 | Fly-back dc/ac conversion circuit with plurality of windings |
| WO2019001217A1 (en) * | 2017-06-30 | 2019-01-03 | 广州金升阳科技有限公司 | Active clamping flyback switching power supply circuit |
| WO2022033239A1 (en) * | 2020-08-10 | 2022-02-17 | 广州金升阳科技有限公司 | Current detection circuit, converter, and current detection method for converter |
| CN111969858A (en) * | 2020-08-25 | 2020-11-20 | 特变电工西安柔性输配电有限公司 | High-order energy-taking power circuit and control method thereof |
| CN114336911A (en) * | 2022-02-16 | 2022-04-12 | 北京燕开新源科技有限公司 | Equalizing charge circuit for series batteries |
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