CN109142880B - Quasi-online monitoring device and method for output capacitor of CCM flyback converter - Google Patents

Quasi-online monitoring device and method for output capacitor of CCM flyback converter Download PDF

Info

Publication number
CN109142880B
CN109142880B CN201710508755.6A CN201710508755A CN109142880B CN 109142880 B CN109142880 B CN 109142880B CN 201710508755 A CN201710508755 A CN 201710508755A CN 109142880 B CN109142880 B CN 109142880B
Authority
CN
China
Prior art keywords
output
capacitor
unit
current
esr
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201710508755.6A
Other languages
Chinese (zh)
Other versions
CN109142880A (en
Inventor
曹诚
姚凯
周世林
韩旭芝
杨思文
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nanjing University of Science and Technology
Original Assignee
Nanjing University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanjing University of Science and Technology filed Critical Nanjing University of Science and Technology
Priority to CN201710508755.6A priority Critical patent/CN109142880B/en
Publication of CN109142880A publication Critical patent/CN109142880A/en
Application granted granted Critical
Publication of CN109142880B publication Critical patent/CN109142880B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G01R27/2605—Measuring capacitance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/16—Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/40—Testing power supplies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/64—Testing of capacitors

Abstract

The invention discloses a quasi-online monitoring device and a method for an output capacitor of a CCM flyback converter. The device comprises a Flyback converter main power circuit, a drive circuit, a display unit, a capacitor with known parameters, a current mutual inductance isolation amplification unit and a signal processing module, wherein the signal processing module comprises power circuit control and switching frequency fsThe method comprises six units of calculation, duty ratio D calculation, output voltage sampling, capacitor current trigger sampling and capacitor ESR and C calculation. The method comprises the following steps: detecting a PWM driving pulse signal of a switching tube, processing the PWM driving pulse signal by an open signal processing module to obtain switching frequency and duty ratio, detecting output average voltage, adding a parallel capacitor with known parameters, isolating and amplifying the parallel capacitor by a current transformer, sampling to obtain an instantaneous value of the current of the parallel capacitor, and processing the data to obtain the current ESR and C values of the output filter capacitor. The invention does not need to take down the capacitor in the converter, and provides a basis for predicting the service life of the capacitor and the power supply.

Description

Quasi-online monitoring device and method for output capacitor of CCM flyback converter
Technical Field
The invention belongs to the technical field of monitoring in an electric energy conversion device, and particularly relates to a quasi-online monitoring device and method for an output capacitor of a CCM flyback converter.
Background
Due to the advantages of high efficiency, small size and the like, the switching power supply is widely applied in daily production and life. Generally, in order to obtain a stable output voltage, a capacitor must be used to effectively filter high frequency noise. After the converter works for a period of time, the Capacitance (C) and the Equivalent Series Resistance (ESR) of the capacitor change, and when the change amount is larger than the initial Capacitance C and the Resistance ESR, the capacitor is considered to have failed, and the failure of the capacitor causes the operation failure of the power supply and the system. Buck (Buck), Boost (Boost) and Buck-Boost (Buck-Boost) converters are three basic switching power converters, and other converters can be derived from the three converters. Among them, a CCM (Continuous Current Mode) Flyback converter is widely used in the fields of computer power supplies, communication power supplies, aerospace and the like, so it is very important to monitor ESR and C of an output filter capacitor of the CCM Flyback converter and predict the life thereof. However, in the current method for monitoring the ESR and C of the output filter capacitor of the CCM Flyback converter, the capacitor in the converter is often required to be removed, and the ESR and C values of the capacitor cannot be monitored online efficiently in real time.
Disclosure of Invention
The invention aims to provide a quasi-online monitoring device and a quasi-online monitoring method for an output capacitor of a CCM flyback converter, which can monitor the Equivalent Series Resistance (ESR) and the capacitance value C of a capacitor in real time and accurately predict the service life of an electrolytic capacitor and the service life of a power supply.
The technical solution for realizing the purpose of the invention is as follows: a quasi-online monitoring device for output capacitance of CCM Flyback converter comprises a Flyback converter main power circuit, a driving circuit, a display unit, a capacitance with known parameters, a current mutual inductance isolation amplification unit and a signal processing module, wherein the signal processing module comprises a power circuit control unit, a switching frequency fsThe device comprises a calculating unit, a duty ratio D calculating unit, an output voltage sampling unit, a capacitance current trigger sampling unit and a capacitance ESR and C calculating unit;
the Flyback converter main power circuit comprises an input voltage source VinAnd a switching tube QbFreewheel diode DbCoupling inductor L, output filter capacitor and load RLThe output filter capacitor comprises an Equivalent Series Resistor (ESR) and a capacitor C, wherein a switching tube QbDrain electrode of and voltage source VinIs connected with the positive electrode of the coupling inductor L, one end of the primary side of the coupling inductor L is connected with the switching tube QbCoupled to the end of the inductor L and a freewheeling diode DbIs connected with the other end of the primary side of the coupling inductor L and a voltage source VinIs connected to the negative pole of the freewheeling diode DbRespectively with one end of an equivalent series resistance ESR and a load RLIs connected to equivalent series resistance ESRIs connected with one end of a capacitor C, the other end of the capacitor C and a load RLThe other end of the coupling inductor L is connected with the dotted end of the secondary side of the coupling inductor L, and a load RLWith an output average voltage V acrosso；
The input end of the power circuit control unit is respectively connected with a voltage source V of a Flyback converter main power circuitinAnd output average voltage VoThe PWM signals at the output end of the power circuit control unit are respectively connected with the switching frequency fsCalculating unit, duty ratio D calculating unit, output average voltage V of Flyback converter main power circuitoThe PWM signals connected to the output end of the output voltage sampling unit, the current mutual inductance isolation amplification unit and the output end of the power circuit control unit are connected to the capacitance current trigger sampling unit, and the switching frequency fsThe output ends of the calculation unit, the duty ratio D calculation unit, the output voltage sampling unit and the capacitance current trigger sampling unit are all connected to the capacitance ESR and C calculation unit, and the output ends of the capacitance ESR and C calculation unit are connected to the display unit;
the input end of the driving circuit is connected with the PWM signal of the output end of the power circuit control unit, and the output end of the driving circuit is connected with the switching tube QbA gate electrode of (2).
Further, the signal processing module is a DSP chip TMS320F 28335.
Further, the display unit is a 1602 liquid crystal display.
A quasi-online monitoring method for an output capacitor of a CCM flyback converter comprises the following steps:
step 1, connecting a capacitor with known parameters in parallel at an output end, and establishing a power circuit control unit and a switching frequency f in a signal processing modulesThe device comprises a calculating unit, a duty ratio D calculating unit, an output voltage sampling unit, a capacitance current trigger sampling unit and a capacitance ESR and C calculating unit;
step 2, the power circuit control unit of the signal processing module collects the output average voltage V of the Flyback converter main power circuitoAnd an input voltage VinObtaining PWM signal and driving the switch tube Q by the driving circuitb；
Step 3, the PWM signal output by the power circuit control unit is sent to the switching frequency fsA calculating unit and a duty ratio D calculating unit for calculating the duty ratio of the output signalsThe current switching frequency f of the converter is obtained through processing of the computing unitsProcessing the current duty ratio D of the converter by a duty ratio D calculation unit;
step 4, the output average voltage V of the Flyback converter main power circuitoSending the voltage to an output voltage sampling unit to obtain an output average voltage;
and 5, the PWM signal output by the power circuit control unit and the capacitance current i of the current mutual inductance isolation amplification unitxSending the current to a capacitive current trigger sampling unit, and processing the current through a time delay program to obtain an instantaneous value i of the capacitive currentx(DTs)、 ix[(1+9D)Ts/10]、ix[(2+8D)Ts/10]、ix[(3+7D)Ts/10]、ix[(4+6D)Ts/10]、ix[(5+5D)Ts/10]、 ix[(6+4D)Ts/10]、ix[(7+3D)Ts/10]、ix[(8+2D)Ts/10]、ix[(9+D)Ts/10]、ix(Ts) A total of 11 values, TsIs the converter switching period;
step 6, the obtained switching frequency fsDuty ratio D, output average voltage VoAnd instantaneous value i of the capacitive currentx(DTs)、ix[(1+9D)Ts/10]、ix[(2+8D)Ts/10]、ix[(3+7D)Ts/10]、ix[(4+6D)Ts/10]、ix[(5+5D)Ts/10]、 ix[(6+4D)Ts/10]、ix[(7+3D)Ts/10]、ix[(8+2D)Ts/10]、ix[(9+D)Ts/10]、ix(Ts) Sending the signal into a capacitor ESR and C calculation unit (10) for curve fitting and comprehensive processing to obtain the values of the current equivalent series resistance ESR and the current equivalent series resistance C of the output filter capacitor in the Flyback converter;
and 7, the capacitor ESR and C calculating unit sends the obtained equivalent series resistance ESR and capacitor C values to the display unit for real-time display.
Further, the ESR and C calculation unit curve fitting equation in step 6 should be as follows:
Figure BDA0001335268270000031
finding X1、X2、X3And iCx(0)；iCx(0) Is the initial instantaneous value of the capacitive current, t is the time;
then, the formula of the comprehensive processing of the ESR and C calculating unit in the step 6 is as follows:
Figure BDA0001335268270000032
Figure BDA0001335268270000033
wherein ESR is the resistance of the equivalent series resistor, C is the capacitance of the capacitor, and LsFor secondary inductance value, V, of the coupled inductoroFor outputting the average voltage, ESRx is the resistance value of the equivalent series resistor of the parallel capacitor, Cx is the capacitance value of the parallel capacitor, X1、X2、X3Are parameters of the fitted curve.
Compared with the prior art, the invention has the following remarkable advantages: (1) the capacitor in the converter does not need to be taken down; (2) and the ESR and C values of the capacitor are monitored on line, so that a basis is provided for predicting the service life of the capacitor and the power supply.
Drawings
Fig. 1 is an operation waveform in a switching period of a CCM Flyback converter.
Fig. 2 is a schematic diagram of a monitoring method of ESR and C of the output capacitance of the CCMFlyback converter of the present invention.
Wherein: vinInput voltage, Iin-an input current to be supplied to the power supply,
Figure BDA0001335268270000034
-a primary current of a coupling inductor,
Figure BDA0001335268270000035
secondary current of coupling inductor, iC-a capacitive current iCxParallel capacitor current, IoOutput current, Vo-output average voltage, Qb-a switching tube, Db-a diode, an L-coupling inductor, a C-output filter capacitance value, an ESR-equivalent series resistance value, a capacitance value of a Cx-parallel capacitor, an equivalent series resistance value of an ESRx-parallel capacitor, RL-load, Vgs-a switching tube QbDriving voltage, D-duty cycle, t-time, fsConverter switching frequency, Δ ILPeak-to-peak inductor current ripple, vESRVoltage across equivalent series resistance, vC-the voltage on the capacitor.
Detailed Description
The invention is described in further detail below with reference to the figures and the specific embodiments.
The invention designs a device and a method for quasi-online monitoring of ESR and C of output filter capacitors of a flyback (flyback) converter working in a Continuous Current Mode (CCM).
1. Theoretical derivation
Fig. 1 shows operating waveforms in a switching cycle of a CCM flyback converter. When the switch tube QbWhen conducting, the diode DbThe voltage at two ends of the primary side of the coupled inductor L is V when the coupled inductor is cut offinPrimary side current of coupled inductor
Figure BDA0001335268270000041
With Vin/LpThe slope of (c) rises linearly. When the switch tube QbWhen the inductor is turned off, the secondary current of the inductor is coupled
Figure BDA0001335268270000042
Through diode DbFollow current, the voltage at the two secondary sides of the coupling inductor L is-V at the momentoSecondary current of coupled inductor
Figure BDA0001335268270000043
With Vo/LsThe slope of (c) decreases. Since Flyback converters operate in CCM mode, the inductor current is coupled before the end of the switching cycle
Figure BDA0001335268270000044
Does not drop to zero. Current of coupled inductor
Figure BDA0001335268270000045
The average value in a switch off time is
Figure BDA0001335268270000046
Primary side current of coupled inductor
Figure BDA0001335268270000047
And secondary side current
Figure BDA0001335268270000048
The expression in one cycle is as follows:
Figure BDA0001335268270000049
Figure BDA00013352682700000410
wherein VoTo output an average voltage, LpPrimary inductance of the coupling inductor, LsFor coupling inductance secondary inductance value, fsThe switching frequency of the Flyback converter, D the duty ratio of the switching tube and t the time.
The current sum i of the two capacitors can be obtainedC+iCxThe expression of (a) is:
Figure BDA0001335268270000051
can assume that
a1＝0 (4)
b1＝-Io (5)
Figure BDA0001335268270000052
Figure BDA0001335268270000053
The voltage expressions of the two capacitors are respectively
Figure BDA0001335268270000054
Figure BDA0001335268270000055
Because the two capacitors are connected in parallel, the voltages of the two capacitors are equal
vC(t)＝vCx(t) (10)
When in use
Figure BDA0001335268270000056
When the temperature of the water is higher than the set temperature,
Figure BDA0001335268270000057
derived from formula (11)
Figure BDA0001335268270000058
Respectively subjecting the equal sign of formula (12) to Laplace transformation
Figure BDA0001335268270000059
Simple and available
Figure BDA0001335268270000061
The equal sign of the formula (14) is subjected to Laplace inverse transformation to obtain
Figure BDA0001335268270000062
Wherein
Figure BDA0001335268270000063
Figure BDA0001335268270000064
Figure BDA0001335268270000065
Fitting curves can be made according to 11 parallel capacitance values obtained by sampling to obtain X1、X2、X3And iCx(0)。
Substituting formulae (6) and (7) into formulae (16), (17), and (18) can yield:
Figure BDA0001335268270000066
Figure BDA0001335268270000067
in the formula, LsIs inductance value of inductor, ESR is resistance value of equivalent series resistor, C is capacitance value of capacitor, VoFor outputting the average voltage, ESRx is the resistance value of the equivalent series resistor of the parallel capacitor, Cx is the capacitance value of the capacitor of the parallel capacitor, X1、X2、X3Are parameters of the fitted curve.
Based on the equations (19) and (20), the monitoring method of ESR and C of the output filter capacitors of the CCM Flyback converter can be obtained.
2. The invention relates to a quasi-online monitoring device and a method for output capacitance of a CCMFlyback converter
With reference to fig. 2, the quasi-online monitoring device for the output capacitance of the CCM Flyback converter is characterized by comprising a Flyback converter main power circuit 1, a driving circuit 3, a display unit 11, a capacitance 7 with known parameters, a current mutual inductance isolation amplifying unit 8 and a signal processing module, wherein the signal processing module comprises a power circuit control unit 2, a switching frequency fsThe device comprises a calculating unit 4, a duty ratio D calculating unit 5, an output voltage sampling unit 6, a capacitance current trigger sampling unit 9 and a capacitance ESR and C calculating unit 10;
the Flyback converter main power circuit 1 comprises an input voltage source VinAnd a switching tube QbFreewheel diode DbCoupling inductor L, output filter capacitor and load RLThe output filter capacitor comprises an Equivalent Series Resistor (ESR) and a capacitor C, wherein a switching tube QbDrain electrode of and voltage source VinIs connected with the positive electrode of the coupling inductor L, one end of the primary side of the coupling inductor L is connected with the switching tube QbCoupled to the end of the inductor L and a freewheeling diode DbIs connected with the other end of the primary side of the coupling inductor L and a voltage source VinIs connected to the negative pole of the freewheeling diode DbRespectively with one end of an equivalent series resistance ESR and a load RLIs connected to one end of an equivalent series resistance ESR, the other end of the equivalent series resistance ESR is connected to one end of a capacitor C, the other end of the capacitor C and a load RLThe other end of the coupling inductor L is connected with the dotted end of the secondary side of the coupling inductor L, and a load RLWith an output average voltage V acrosso；
The input end of the power circuit control unit 2 is respectively connected with the voltage source V of the Flyback converter main power circuit 1inAnd output average voltage VoThe PWM signals at the output end of the power circuit control unit 2 are respectively connected with the switching frequency fsCalculating unit 4, duty ratio D calculating unit 5 and output average voltage V of Flyback converter main power circuit 1oPWM signals connected to the output ends of the output voltage sampling unit 6, the current mutual inductance isolation amplifying unit 8 and the power circuit control unit 2Are all connected into a capacitance current trigger sampling unit 9 with a switching frequency fsThe output ends of the calculating unit 4, the duty ratio D calculating unit 5, the output voltage sampling unit 6 and the capacitance current trigger sampling unit 9 are all connected to a capacitance ESR and C calculating unit 10, and the output end of the capacitance ESR and C calculating unit 10 is connected to a display unit 11;
the input end of the driving circuit 3 is connected with the PWM signal at the output end of the power circuit control unit 2, and the output end of the driving circuit 3 is connected with the switching tube QbA gate electrode of (2). The signal processing module is a DSP chip TMS320F 28335. The display unit 11 is a 1602 liquid crystal display.
The invention discloses a quasi-online monitoring method for an output capacitor of a CCM flyback converter, which comprises the following steps:
step 1, a capacitor 7 with known parameters is connected in parallel at the output end, a power circuit control unit 2 and a switching frequency f are established in a signal processing modulesThe device comprises a calculating unit 4, a duty ratio D calculating unit 5, an output voltage sampling unit 6, a capacitance current trigger sampling unit 9 and a capacitance ESR and C calculating unit 10;
step 2, the power circuit control unit 2 of the signal processing module collects the output average voltage V of the Flyback converter main power circuit 1oAnd an input voltage VinObtaining PWM signal and driving the switch tube Q by the driving circuit 3b；
Step 3, the PWM signal output by the power circuit control unit 2 is sent to the switching frequency fsA calculating unit 4 and a duty ratio D calculating unit 5 for calculating the duty ratio of the output signalsThe calculation unit 4 processes the current switching frequency f of the convertersThe current duty ratio D of the converter is obtained through the processing of the duty ratio D calculating unit 5;
step 4, the output average voltage V of the Flyback converter main power circuit 1oSending the voltage into an output voltage sampling unit 6 to obtain an output average voltage Vo；
Step 5, the PWM signal output by the power circuit control unit 2 and the capacitance current i of the current mutual inductance isolation amplifying unit 8xSending the current to a capacitive current trigger sampling unit 9, and obtaining an instantaneous value i of the capacitive current through time delay program processingxDTs、 ix[1+9DTs/10]、ix[2+8DTs/10]、ix[3+7DTs/10]、ix[4+6DTs/10]、ix[5+5DTs/10]、ix[6+4DTs/10]、 ix[7+3DTs/10]、ix[8+2DTs/10]、ix[9+DTs/10]、ixTsA total of 11 values, TsIs the converter switching period;
step 6, the obtained switching frequency fsDuty ratio D, output average voltage VoAnd instantaneous value i of the capacitive currentxDTs、ix[1+9DTs/10]、ix[2+8DTs/10]、ix[3+7DTs/10]、ix[4+6DTs/10]、ix[5+5DTs/10]、 ix[6+4DTs/10]、ix[7+3DTs/10]、ix[8+2DTs/10]、ix[9+DTs/10]、ixTsSending the signal into a capacitor ESR and C calculation unit 10 for curve fitting and comprehensive processing to obtain the current equivalent series resistance ESR and the current equivalent series resistance C of the output filter capacitor in the Flyback converter;
the ESR and C calculation unit 10 curve fitting equation should be as follows:
Figure BDA0001335268270000081
finding X1、X2、X3And iCx(0)；iCx(0) Is the initial instantaneous value of the capacitive current, t is the time;
the formula for the combined processing by the ESR and C calculation unit 10 in step 6 is then as follows:
Figure BDA0001335268270000082
Figure BDA0001335268270000083
wherein ESR is the resistance of the equivalent series resistor, C is the capacitance of the capacitor, and LsFor secondary inductance value, V, of the coupled inductoroFor outputting the average voltage, ESRx is the resistance value of the equivalent series resistor of the parallel capacitor, Cx is the capacitance value of the parallel capacitor, X1、X2、X3Are parameters of the fitted curve.
And 7, sending the obtained equivalent series resistance ESR and capacitance C values to a display unit 11 for real-time display by a capacitance ESR and C calculation unit 10.
The invention designs a high-efficiency and stable quasi-online monitoring device and method of Equivalent Series Resistance (ESR) and capacitance (C) of an output filter capacitor aiming at the output filter capacitor in a CCM Flyback converter.

Claims (4)

1. The quasi-online monitoring device for the output capacitance of the CCM Flyback converter is characterized by comprising a Flyback converter main power circuit (1), a driving circuit (3), a display unit (11), a capacitance (7) with known parameters, a current mutual inductance isolation amplification unit (8) and a signal processing module, wherein the signal processing module comprises a power circuit control unit (2), a switching frequency fsThe device comprises a calculating unit (4), a duty ratio D calculating unit (5), an output voltage sampling unit (6), a capacitance current trigger sampling unit (9) and a capacitance ESR and C calculating unit (10);
the Flyback converter main power circuit (1) comprises an input voltage source VinAnd a switching tube QbFreewheel diode DbCoupling inductor L, output filter capacitor and load RLThe output filter capacitor comprises an Equivalent Series Resistor (ESR) and a capacitor C, wherein a switching tube QbDrain electrode of and voltage source VinIs connected with the positive electrode of the coupling inductor L, one end of the primary side of the coupling inductor L is connected with the switching tube QbIs connected with the drain of the coupling inductor L, the synonym end of the secondary side of the coupling inductor L and the freewheeling diode DbIs connected with the other end of the primary side of the coupling inductor L and a voltage source VinIs connected to the negative pole of the freewheeling diode DbRespectively with one end of an equivalent series resistance ESR and a load RLIs connected to one end of an equivalent series resistance ESR, the other end of the equivalent series resistance ESR is connected to one end of a capacitor C, the other end of the capacitor C and a load RLThe other end of the coupling inductor L is connected with the dotted end of the secondary side of the coupling inductor L, and a load RLWith an output average voltage V acrosso；
The input end of the power circuit control unit (2) is respectively connected with a voltage source V of the Flyback converter main power circuit (1)inAnd output average voltage VoThe PWM signals at the output end of the power circuit control unit (2) are respectively connected with the switching frequency fsA calculating unit (4), a duty ratio D calculating unit (5), and an output average voltage V of the Flyback converter main power circuit (1)oPWM signals connected to the output end of the output voltage sampling unit (6), the output end of the current mutual inductance isolation amplification unit (8) and the output end of the power circuit control unit (2) are connected to the capacitance current trigger sampling unit (9), and the switching frequency fsThe output ends of the calculating unit (4), the duty ratio D calculating unit (5), the output voltage sampling unit (6) and the capacitance current trigger sampling unit (9) are all connected to a capacitance ESR and C calculating unit (10), and the output ends of the capacitance ESR and C calculating unit (10) are connected to a display unit (11);
the input end of the driving circuit (3) is connected with the PWM signal of the output end of the power circuit control unit (2), and the output end of the driving circuit (3) is connected with the switching tube QbA gate electrode of (a);
a capacitor (7) with known parameters is connected in parallel with the output end of a Flyback converter main power circuit (1), and a power circuit control unit (2) and a switching frequency f are established in a signal processing modulesThe device comprises a calculating unit (4), a duty ratio D calculating unit (5), an output voltage sampling unit (6), a capacitance current trigger sampling unit (9) and a capacitance ESR and C calculating unit (10);
the power circuit control unit (2) of the signal processing module acquires the output average voltage V of the Flyback converter main power circuit (1)oAnd an input voltage VinObtaining a PWM signal and driving a switch tube Q through a driving circuit (3)b；
The PWM signal output by the power circuit control unit (2) is sent to the switching frequency fsA calculating unit (4) and a duty ratio D calculating unit (5) for calculating the duty ratio through the switching frequency fsThe current switching frequency f of the converter is obtained by processing of a computing unit (4)sThe current duty ratio D of the converter is obtained through the processing of a duty ratio D calculating unit (5);
output average voltage V of Flyback converter main power circuit (1)oSending the voltage to an output voltage sampling unit (6) to obtain an output average voltage;
PWM signals output by the power circuit control unit (2) and capacitance current i of the current mutual inductance isolation amplification unit (8)xSending the current to a capacitive current trigger sampling unit (9), and obtaining an instantaneous value i of the capacitive current through time delay program processingx(DTs)、ix[(1+9D)Ts/10]、ix[(2+8D)Ts/10]、ix[(3+7D)Ts/10]、ix[(4+6D)Ts/10]、ix[(5+5D)Ts/10]、ix[(6+4D)Ts/10]、ix[(7+3D)Ts/10]、ix[(8+2D)Ts/10]、ix[(9+D)Ts/10]、ix(Ts) A total of 11 values, TsIs the converter switching period;
the obtained switching frequency fsDuty ratio D, output average voltage VoAnd instantaneous value i of the capacitive currentx(DTs)、ix[(1+9D)Ts/10]、ix[(2+8D)Ts/10]、ix[(3+7D)Ts/10]、ix[(4+6D)Ts/10]、ix[(5+5D)Ts/10]、ix[(6+4D)Ts/10]、ix[(7+3D)Ts/10]、ix[(8+2D)Ts/10]、ix[(9+D)Ts/10]、ix(Ts) Sending the signal into a capacitor ESR and C calculation unit (10) for curve fitting and comprehensive processing to obtain the values of the current equivalent series resistance ESR and the current equivalent series resistance C of the output filter capacitor in the Flyback converter;
the capacitor ESR and C calculating unit (10) sends the obtained equivalent series resistance ESR and capacitor C values to the display unit (11) for real-time display;
the ESR and C calculation unit (10) curve fitting equation should be as follows:
Figure FDA0002683746370000021
finding X1、X2、X3And iCx(0)；iCx(0) Is the initial instantaneous value of the capacitive current, t is the time;
the formula of ESR and C calculation unit (10) integrated processing is as follows:
Figure FDA0002683746370000022
Figure FDA0002683746370000023
wherein ESR is the resistance of the equivalent series resistor, C is the capacitance of the capacitor, and LsFor secondary inductance value, V, of the coupled inductoroFor outputting the average voltage, ESRx is the resistance value of the equivalent series resistor of the parallel capacitor, Cx is the capacitance value of the parallel capacitor, X1、X2、X3Are parameters of the fitted curve.
2. The device of claim 1, wherein the signal processing module is a DSP chip TMS320F 28335.
3. The device for quasi-online monitoring of the output capacitance of the CCM flyback converter according to claim 1, wherein the display unit (11) is a 1602 liquid crystal display.
4. A quasi-online monitoring method for an output capacitor of a CCM flyback converter is characterized by comprising the following steps:
step 1, connecting a capacitor (7) with known parameters in parallel at the output end of a Flyback converter main power circuit (1), and establishing a power circuit control unit (2) and a switching frequency f in a signal processing modulesThe device comprises a calculating unit (4), a duty ratio D calculating unit (5), an output voltage sampling unit (6), a capacitance current trigger sampling unit (9) and a capacitance ESR and C calculating unit (10);
step 2, a power circuit control unit (2) of the signal processing module collects the output average voltage V of a Flyback converter main power circuit (1)oAnd an input voltage VinObtaining a PWM signal and driving a switch tube Q through a driving circuit (3)b；
Step 3, sending the PWM signal output by the power circuit control unit (2) to a switching frequency fsA calculating unit (4) and a duty ratio D calculating unit (5) for calculating the duty ratio through the switching frequency fsThe current switching frequency f of the converter is obtained by processing of a computing unit (4)sThe current duty ratio D of the converter is obtained through the processing of a duty ratio D calculating unit (5);
step 4, outputting the average voltage V of the main power circuit (1) of the Flyback converteroSending the voltage to an output voltage sampling unit (6) to obtain an output average voltage;
and 5, isolating the PWM signal output by the power circuit control unit (2) and the capacitance current i of the current mutual inductance isolation amplifying unit (8)xSending the current to a capacitive current trigger sampling unit (9), and obtaining an instantaneous value i of the capacitive current through time delay program processingx(DTs)、ix[(1+9D)Ts/10]、ix[(2+8D)Ts/10]、ix[(3+7D)Ts/10]、ix[(4+6D)Ts/10]、ix[(5+5D)Ts/10]、ix[(6+4D)Ts/10]、ix[(7+3D)Ts/10]、ix[(8+2D)Ts/10]、ix[(9+D)Ts/10]、ix(Ts) A total of 11 values, TsIs the converter switching period;
step 6, the obtained switching frequency fsDuty ratio D, output average voltage VoAnd instantaneous value i of the capacitive currentx(DTs)、ix[(1+9D)Ts/10]、ix[(2+8D)Ts/10]、ix[(3+7D)Ts/10]、ix[(4+6D)Ts/10]、ix[(5+5D)Ts/10]、ix[(6+4D)Ts/10]、ix[(7+3D)Ts/10]、ix[(8+2D)Ts/10]、ix[(9+D)Ts/10]、ix(Ts) Sending the signal into a capacitor ESR and C calculation unit (10) for curve fitting and comprehensive processing to obtain the values of the current equivalent series resistance ESR and the current equivalent series resistance C of the output filter capacitor in the Flyback converter;
step 7, the capacitor ESR and C calculating unit (10) sends the obtained equivalent series resistance ESR and capacitor C values to the display unit (11) for real-time display;
the ESR and C calculation unit (10) curve fitting equation in step 6 should be as follows:
Figure FDA0002683746370000031
finding X1、X2、X3And iCx(0)；iCx(0) Is the initial instantaneous value of the capacitive current, t is the time;
then according to the formula of the ESR and C calculation unit (10) in the step 6, the comprehensive processing is as follows:
Figure FDA0002683746370000041
Figure FDA0002683746370000042
wherein ESR is the resistance of the equivalent series resistor, C is the capacitance of the capacitor, and LsFor secondary inductance value, V, of the coupled inductoroFor outputting the average voltage, ESRx is the resistance value of the equivalent series resistor of the parallel capacitor, Cx is the capacitance value of the parallel capacitor, X1、X2、X3Are parameters of the fitted curve.
CN201710508755.6A 2017-06-28 2017-06-28 Quasi-online monitoring device and method for output capacitor of CCM flyback converter Active CN109142880B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201710508755.6A CN109142880B (en) 2017-06-28 2017-06-28 Quasi-online monitoring device and method for output capacitor of CCM flyback converter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201710508755.6A CN109142880B (en) 2017-06-28 2017-06-28 Quasi-online monitoring device and method for output capacitor of CCM flyback converter

Publications (2)

Publication Number Publication Date
CN109142880A CN109142880A (en) 2019-01-04
CN109142880B true CN109142880B (en) 2020-12-04

Family

ID=64803024

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201710508755.6A Active CN109142880B (en) 2017-06-28 2017-06-28 Quasi-online monitoring device and method for output capacitor of CCM flyback converter

Country Status (1)

Country Link
CN (1) CN109142880B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111505524B (en) * 2019-01-30 2022-09-23 台达电子工业股份有限公司 On-line monitoring method of cascade converter and applicable cascade converter
CN112710963B (en) * 2020-12-28 2023-10-13 哈尔滨工业大学（深圳） Switching power supply fault detection method based on impulse response
CN113219257B (en) * 2021-04-29 2022-01-07 深圳市东昕科技有限公司 Parameter measuring circuit of capacitor and ESR capacity measuring instrument of capacitor
CN113315372B (en) * 2021-05-26 2023-02-10 南京矽力微电子技术有限公司 Power converter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104459338A (en) * 2014-12-26 2015-03-25 青岛歌尔声学科技有限公司 Capacitor capacitance value measuring device and measuring method
CN105162332A (en) * 2015-09-25 2015-12-16 南京理工大学 Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in CCM (Continuous Current Mode) flyback converter
CN105915049A (en) * 2016-04-06 2016-08-31 南京理工大学 Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in DCM boost converter

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9601997B2 (en) * 2013-03-29 2017-03-21 Virginia Tech Intellectual Properties, Inc. V^2 power converter control with capacitor current ramp compensation
US9893604B2 (en) * 2015-07-21 2018-02-13 Robert W. Horst Circuit with low DC bias storage capacitors for high density power conversion

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104459338A (en) * 2014-12-26 2015-03-25 青岛歌尔声学科技有限公司 Capacitor capacitance value measuring device and measuring method
CN105162332A (en) * 2015-09-25 2015-12-16 南京理工大学 Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in CCM (Continuous Current Mode) flyback converter
CN105915049A (en) * 2016-04-06 2016-08-31 南京理工大学 Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in DCM boost converter

Also Published As

Publication number Publication date
CN109142880A (en) 2019-01-04

Similar Documents

Publication Publication Date Title
CN107167747B (en) Device and method for monitoring inductor and output capacitor of CCM (continuous current mode continuous current) buck converter
CN109142880B (en) Quasi-online monitoring device and method for output capacitor of CCM flyback converter
CN107132422B (en) Device and method for monitoring ESR and C of output capacitor of CCM boost converter
CN103412265B (en) CCM buck converter output capacitance ESR and the monitoring device and method of C
CN107153137B (en) The monitoring device and method of DCM booster converter inductance and output capacitance
CN107121611A (en) The method for monitoring the failure of DCMBoostPFC converters output capacitance
CN105915049A (en) Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in DCM boost converter
CN111856145B (en) Device and method for monitoring ESR and L of boost DC/DC converter
CN109143110B (en) Device and method for monitoring inductance and output capacitance of DCM buck converter
CN104779790A (en) Switched inductance quasi-Z source DC-DC converter circuit
CN103633839A (en) Improved Z-source boosting DC (direct current)-DC converter
CN111555625A (en) Online monitoring device and method for output capacitor and secondary inductor of DCM flyback converter
CN104836445A (en) Device and method for monitoring ESR and C of output capacitor of flyback PFC converter
CN105162323A (en) Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in DCM (Discontinuous Current Mode) buck converter
CN103490622A (en) Single-switch high-gain boost converter
CN104009633A (en) Current continuous type high-gain DC-DC converter circuit
CN105162332A (en) Device and method for monitoring ESR (Equivalent Series Resistance) and C (Capacitance) of output capacitor in CCM (Continuous Current Mode) flyback converter
CN105137200A (en) Monitoring device of CCM Buck-Boost convertor output capacitor and method thereof
CN204068745U (en) A kind of transformer leakage inductance Energy harvesting type flyback sourse system
CN203722474U (en) Quasi-Z-source DC-DC boost converter circuit
CN103490635A (en) Improved H bridge buck-boost DC converter and control method thereof
CN203590025U (en) Single-switch high-gain boost converter
CN110618391A (en) Monitoring device and method for ESR and L of step-down DC/DC converter
CN202840953U (en) Three-grade voltage-multiplying DC-DC converter
CN202334349U (en) Direct current isolated grid-connected inversion circuit and photovoltaic inversion system

Legal Events

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