CN113726171B - Control method of LLC resonant converter based on forgetting filtering algorithm - Google Patents

Control method of LLC resonant converter based on forgetting filtering algorithm Download PDF

Info

Publication number
CN113726171B
CN113726171B CN202110795311.1A CN202110795311A CN113726171B CN 113726171 B CN113726171 B CN 113726171B CN 202110795311 A CN202110795311 A CN 202110795311A CN 113726171 B CN113726171 B CN 113726171B
Authority
CN
China
Prior art keywords
forgetting
llc resonant
output
filtering algorithm
regulator
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
CN202110795311.1A
Other languages
Chinese (zh)
Other versions
CN113726171A (en
Inventor
王金平
刘圣宇
姜浩然
季圣植
姜卫东
陈耀辉
蒋智
王纪琮
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.)
Tianchang Longyuan Electronics Co ltd
Hefei University of Technology
Original Assignee
Tianchang Longyuan Electronics Co ltd
Hefei University of 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 Tianchang Longyuan Electronics Co ltd, Hefei University of Technology filed Critical Tianchang Longyuan Electronics Co ltd
Priority to CN202110795311.1A priority Critical patent/CN113726171B/en
Publication of CN113726171A publication Critical patent/CN113726171A/en
Application granted granted Critical
Publication of CN113726171B publication Critical patent/CN113726171B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • H02M1/15—Arrangements for reducing ripples from dc input or output using active elements
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention relates to a control method of an LLC resonant converter based on a forgetting filtering algorithm, which comprises the following steps: collecting output current of an LLC resonant circuit; processing the output current sequentially through a PID controller and a forgetting filtering algorithm to obtain control parameters approaching to the state of the system; the switching frequency of the chopper of the LLC resonant circuit is controlled by combining the output parameters through the voltage-controlled oscillator, and the voltage ripple at the input end of the LLC resonant circuit is restrained; the control method can effectively inhibit the LLC resonant converter from outputting 2-frequency multiplication ripple with smaller algorithm complexity and higher flexibility.

Description

Control method of LLC resonant converter based on forgetting filtering algorithm
Technical Field
The invention belongs to the field of power electronics technology application, in particular to the field of LLC resonant converter control based on a forgetting filtering algorithm.
Background
In many of the existing LLC resonant converters, the problem of output 2-frequency doubling ripple occurs along with the access of the power grid through an uncontrolled rectifier bridge, and the frequency of the LLC resonant converters is about 100Hz, which affects the safe and stable operation of the device, and even causes the device to fail to work normally. Therefore, the limitation of the output ripple has become an important issue in the control research work of LLC resonant converters. In the prior related art application, the output ripple of the LLC resonant converter is reduced mainly by combining the adjustment of the resonant frequency in a feedback control manner. But inside the feedback control loop different algorithms will directly lead to different ripple suppression effects. How to optimize the internal algorithm of the feedback control loop becomes the difficulty of the LLC resonant converter output ripple suppression research.
Disclosure of Invention
In order to solve the problem of output current fluctuation caused by direct-current side voltage fluctuation, the invention realizes the aim through the following technical scheme:
a control method of LLC resonant converter based on forgetting filtering algorithm comprises the following steps,
s1, collecting output current of an LLC resonant circuit;
s2, the output current is processed through a PID controller and a forgetting filtering algorithm in sequence, and control parameters approaching to the state of the system are obtained; the control parameter is a frequency-controlled voltage signal;
s3, controlling the switching frequency of the LLC resonant circuit chopper by combining the output parameters through the voltage-controlled oscillator, and counteracting the ripple influence of the input end of the LLC resonant circuit.
As a further optimization scheme of the invention, the forgetting filtering algorithm in the step S2 comprises the following steps,
s21, obtaining an output parameter Out_PI (n) after the output current of the LLC resonant circuit is regulated by a PID controller under the n period;
s22, obtaining an estimated value parameter Out_PI' (n) after forgetting filtering processing of an output parameter Out_PI (n) of the PID controller under the n period;
s23, obtaining output values out_PI ' (n-1), out_PI ' (n-2) and out_PI ' (n-3) after n-1, n-2 and n-3 periodic forgetting filtering through periodic iteration; wherein n-1 represents the last cycle, n-2 represents the last two cycles, and n-3 represents the last three cycles;
s24, averaging the output values of the n-1, n-2 and n-3 cycles after iteration and the current n cycle forgetting filtering to obtain an input estimated value Out_PI "(n) required by an n cycle forgetting filtering algorithm;
s25, introducing forgetting factor k f And taking the output out_PI' (n) of the forgetting algorithm of the current period as the input value of the forgetting filtering algorithm of the next period to obtain other control parameters, wherein k is the same as the input value of the forgetting filtering algorithm of the next period f <1。
As a further optimization of the present invention, the output parameter out_pi (n) in the step S21 satisfies the expression out_pi (n) =k 0 *Out_Err(n)+k 1 Out_Err_Int(n)。
As a further optimization of the present invention, in the step S25, the forgetting factor k is set f The final output expression after introducing the forgetting filtering algorithm is:
Out_PI′(n)＝k f Out_PI(n)+(1-k f )Out_PI″(n)。
the invention has the beneficial effects that:
1) The control method can effectively inhibit the LLC resonant converter output 2 frequency multiplication ripple with smaller algorithm complexity and higher flexibility;
2) The control method of the invention can adjust the forgetting depth to a certain extent by introducing forgetting factors, and is applicable to LLC resonant converter systems with different parameter requirements.
Drawings
FIG. 1 is a schematic flow chart of a control method of the present invention;
FIG. 2 is a main circuit diagram of an LLC resonant converter;
FIG. 3 is a diagram of different resonant capacitor designs of the LLC resonant converter main circuit;
FIG. 4 is a schematic diagram of the LLC resonant converter main circuit and its control loop design;
FIG. 5 is a schematic diagram of the application of a forgetting filtering algorithm in an LLC resonant converter;
FIG. 6 is a waveform of LLC resonant converter output current based on a conventional algorithm;
FIG. 7 illustrates LLC resonant converter output current waveforms based on a forgetting filtering algorithm;
Detailed Description
The following detailed description of the present application is provided in conjunction with the accompanying drawings, and it is to be understood that the following detailed description is merely illustrative of the application and is not to be construed as limiting the scope of the application, since numerous insubstantial modifications and adaptations of the application will be to those skilled in the art in light of the foregoing disclosure.
A control method of an LLC resonant converter based on a forgetting filtering algorithm as shown in fig. 1 to 7, comprising the steps of,
s1, collecting output current of an LLC resonant circuit;
s2, the output current is processed through a PID controller and a forgetting filtering algorithm in sequence, and control parameters approaching to the state of the system are obtained; the control parameter refers to a frequency-controlled voltage signal, the frequency of the voltage signal is adjustable, and the value of the voltage signal is specific, and the voltage signal is obtained through processing of a PID controller and a forgetting filtering algorithm.
S3, controlling the switching frequency of the LLC resonant circuit chopper by combining the output parameters through the voltage-controlled oscillator, and counteracting the ripple influence of the input end of the LLC resonant circuit.
In order to facilitate an understanding of the control method of the present invention, a further description will be given below in connection with a specific LLC resonant converter main circuit; it should be noted that the algorithm of the present invention may be applied to, but is not limited to, the following specific LLC resonant converter forms;
the main circuit diagram of the classical LLC resonant converter is shown in fig. 2, which comprises a half-bridge or full-bridge chopper with a driving circuit, a resonant network formed by inductance and capacitance, an isolation transformer, a rectifying and filtering circuit and the like, wherein the half-bridge or full-bridge chopper is connected with a power grid;
the chopper can be composed of two MOSFET tubes and a driving circuit thereof, wherein driving signals of the two tubes are complementary, and each driving signal is 50%;
the series resonant network can be composed of resonant inductance and resonant capacitance, and the specific resonant network design is more than one, such as the LLC resonant converter main circuit shown in FIG. 3 with different resonant capacitance design diagrams;
the isolation transformer can realize an isolation function, and Lm is the excitation inductance thereof. The two terminals D1 and D2 and the capacitor Co together form a rectifying and filtering circuit;
FIG. 4 is a schematic diagram of a circuit including an LLC resonant converter and a controller; for convenience of analysis, specific device designs in the feedback control loop are omitted, and only descriptions of module functions are reserved; as can be seen from fig. 4, the feedback control loop comprises three parts, i.e. PID regulation, forgetting filtering and voltage controlled oscillator, wherein the input of the PID regulation is sampling of the output current in the main circuit, and the output is used as the input of the forgetting filtering algorithm; after the action of the forgetting filtering algorithm, the voltage-controlled oscillator obtains parameter information which is closer to the system state; then, the switching frequency of a chopper in a main circuit is controlled through an output driving circuit of the voltage-controlled oscillator, so that two MOSFET tubes are complementarily conducted under the action of a driving signal;
because the output voltage and the input voltage of the LLC resonant converter and the switching frequency of the chopper have great relation, the output parameters of the voltage-controlled oscillator are proper, and the influence of frequency multiplication ripple of the input voltage 2 can be counteracted by controlling the chopping frequency, so that the effective inhibition of the ripple of the output voltage is realized; meanwhile, in the process, the input of the voltage-controlled oscillator, namely the design of the adjustment parameters after forgetting the filtering function, plays an important role;
specifically, the principle of the forgetting filtering algorithm is shown in fig. 5, wherein, after the output current sample of the LLC resonant converter is subjected to PID adjustment, an output is obtained, which is denoted as out_pi (n), and the expression is shown in the formula (1):
Out_PI(n)＝k 0 *Out_Err(n)+k 1 Out_Err_Int(n) (1)
where n represents the current period, (n-1) represents the LST1 period, (n-2) represents the LST2 period, and so on;
Out_PI (n) is the output of the PI regulator, K 0 Is the "scale" adjustment factor of the PI regulator, out_err (n) refers to the PI regulator input, and the multiplication of K0 and out_err (n) is the "scale" adjustment of the PI regulator;
K 1 is the "integral" adjustment factor of the PI regulator, out_Err_Int (n) refers to the PI regulator performing "integral" processing based on Out_Err (n), and the multiplication of K1 and Out_Err (n) is performedPerforming an "integral" adjustment of the PI regulator; the adjustment of the PI regulator will generally be based on a reference value (denoted I herein ref ) This reference value will participate in the specific "proportional integral" adjustment of the input signal by the PI regulator; specifically, out_Err (n) refers to the PI regulator input, and in the present invention specifically refers to the output current sample value I 0 And reference value I ref A difference between;
the output after forgetting filtering is called as Out_PI '(n), and output values Out_PI' (n-1), out_PI '(n-2) and Out_PI' (n-3) after periodic filtering of LST1, LST2 and LST3 are obtained through periodic iteration;
averaging the output values of the iterated LST1, LST2 and LST3 periods after filtering with the current period, taking the averaged output values as an input estimated value of a forgetting filtering algorithm of the current period, and recording the averaged output values as out_PI "(n);
finally, introducing forgetting factor k f (k f <1) The final output expression after the forgetting factor is introduced into the forgetting filtering algorithm is shown as the formula (2):
Out_PI′(n)＝k f Out_PI(n)+(1-k f )Out_PI″(n) (2)
the final output value obtained by the relation is used as the input of a voltage-controlled oscillator, so that the control and adjustment of the switching frequency are carried out, the chopper frequency is controlled to counteract the influence of the frequency multiplication ripple of the input voltage 2, and the effective inhibition of the output voltage ripple is realized;
for easy understanding, the above forgetting filtering algorithm is described in detail as follows:
overall, the output expression of the current period (n period) forgetting filtering algorithm is:
Out_PI′(n)＝k f Out_PI(n)+(1-k f )Out_PI″(n)
wherein: k (k) f Is a forgetting filtering factor and can be specifically adjusted according to actual needs;
Out_PI (n) is the output of the PI regulator, which is one input of Out_PI' (n);
out_pi "(n) is an estimate of an n-cycle forgetting filter algorithm, which is another input to out_pi' (n), and which averages the output values of n-1, n-2, n-3 cycles and the current cycle forgetting filter algorithm, and its specific expression is:
Figure BDA0003162616620000061
out_PI' (n-1) is the output of the forgetting filtering algorithm in the last period, and the other analogy is that;
the formula is sequentially brought into an output Out_PI' (n) expression of an n-period forgetting filtering algorithm, and a final output value can be obtained; the method plays a key role in obtaining more proper parameters and stability for the system based on the thought of periodic iteration;
in order to verify the output characteristics of the control method in this embodiment, the control method based on the forgetting filtering algorithm and the control method according to the conventional algorithm in this embodiment are respectively used in an LLC converter system, and the LLC converter system is operated to obtain the following experimental results:
as can be seen from comparing fig. 6 and fig. 7, the output current controlled by the control method of the LLC resonant converter based on the forgetting filtering algorithm has a significantly smaller ripple than the output current waveform of the LLC resonant converter using the conventional algorithm.
The invention can effectively inhibit the LLC resonant converter from outputting 2-frequency ripple by only making related designs on the program on the premise of not increasing the system cost with smaller algorithm complexity and more practical flexibility; meanwhile, the invention has good compatibility, and from the control optimization view of the whole LLC resonant converter system, the invention can cooperate with other optimization strategies of the existing LLC resonant converter to furthest inhibit the output ripple problem of the LLC resonant converter;
in addition, the invention has good portability, and in the specific design details of a plurality of LLC resonant converters related to data processing, reference can be made to the idea of using the control method of the forgetting filtering algorithm in the invention.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.

Claims (1)

1. A control method of LLC resonant converter based on forgetting filtering algorithm includes the following steps:
s1, collecting output current of an LLC resonant circuit;
s2, processing the output current through a PI regulator and a forgetting filtering algorithm in sequence to obtain control parameters approaching to the state of the system, wherein the method comprises the following steps:
s21, obtaining an output parameter Out_PI (n) after the output current of the LLC resonant circuit is regulated by a PI regulator in n periods, wherein the output parameter Out_PI (n) meets the following expression: out_pi (n) =k 0 *Out_Err(n)+k 1 *Out_Err_Int(n)，k 0 Is the "proportional" regulator factor, k, of the PI regulator 1 Is the "integral" adjustment factor of the PI regulator, out_err (n) refers to the PI regulator input, out_err_int (n) refers to the PI regulator performing an "integral" process based on out_err (n);
s22, carrying Out forgetting filtering processing on an output parameter Out_PI (n) under n periods to obtain an output value Out_PI' (n) of an n-period forgetting filtering algorithm;
s23, respectively obtaining out_PI ' (n-1), out_PI ' (n-2) and out_PI ' (n-3) of n-1, n-2 and n-3 periodic forgetting filtering output values through periodic iteration; wherein n-1 represents the last cycle, n-2 represents the last two cycles, and n-3 represents the last three cycles;
s24, averaging the iterated n-1, n-2 and n-3 periods and the current n period forgetting filtering output value to obtain an estimated value Out-PI' (n) of the current period filtering algorithm;
s25, introducing forgetting factor k f Taking the output value out_PI '(n) of the current period filtering algorithm as the input value of the forgetting filtering algorithm of the next period to obtain the control parameter, wherein the expression of out_PI' (n) is out_PI′(n)＝k f Out_PI(n)+(1-k f ) Out_pi "(n), wherein the forgetting factor k f The control parameter is a voltage signal with controlled frequency;
s3, controlling the switching frequency of the LLC resonant circuit chopper by combining the control parameters through the voltage-controlled oscillator, and counteracting the ripple influence of the input end of the LLC resonant circuit.
CN202110795311.1A 2021-07-14 2021-07-14 Control method of LLC resonant converter based on forgetting filtering algorithm Active CN113726171B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110795311.1A CN113726171B (en) 2021-07-14 2021-07-14 Control method of LLC resonant converter based on forgetting filtering algorithm

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110795311.1A CN113726171B (en) 2021-07-14 2021-07-14 Control method of LLC resonant converter based on forgetting filtering algorithm

Publications (2)

Publication Number Publication Date
CN113726171A CN113726171A (en) 2021-11-30
CN113726171B true CN113726171B (en) 2023-05-02

Family

ID=78673281

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110795311.1A Active CN113726171B (en) 2021-07-14 2021-07-14 Control method of LLC resonant converter based on forgetting filtering algorithm

Country Status (1)

Country Link
CN (1) CN113726171B (en)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106329895B (en) * 2015-06-17 2020-10-27 雅达电子国际有限公司 LLC resonant converter and method for suppressing ripple in output voltage thereof
US11307261B2 (en) * 2017-03-31 2022-04-19 Mitsubishi Electric Corporation Rechargeable battery state estimation device

Also Published As

Publication number Publication date
CN113726171A (en) 2021-11-30

Similar Documents

Publication Publication Date Title
CN102684464B (en) Resonant converter device and the method for resonant converter device
US8861236B2 (en) Switching power supply with self-optimizing efficiency
TWI511431B (en) Dc/dc converter and method for controlling the same
US10819224B2 (en) Power factor correction circuit, control method and controller
US20050270813A1 (en) Parallel current mode control
CN110212767A (en) Realize the digital control method of LLC resonant converter multistep frequency modulation
US11114859B2 (en) Power conversion system, photovoltaic optimizer and power tracking method thereof
JP2001045763A (en) Converter circuit
CN112350565B (en) Cascade model-free predictive control system based on single-phase Boost PFC converter and control method thereof
CN110086336B (en) Power factor correction circuit, control method and controller
CN108880265B (en) A kind of LLC resonant converter automatic resonance frequency tracker method
CN112953250B (en) Power supply control method, power supply module and storage medium
EP2590307A2 (en) Power supply device and method for regulating dead time
Chen et al. Simplified hysteresis sliding-mode control for superbuck converter
CN113726171B (en) Control method of LLC resonant converter based on forgetting filtering algorithm
Sankaranarayanan et al. Online efficiency optimization of a closed-loop controlled SiC-based boost converter
US20240128860A1 (en) Apfc converter control method, apfc converter, and industrial power supply
CN107872072B (en) Current control system of L-type grid-connected inverter and active high-frequency damping method thereof
Bhardwaj et al. Online LCL filter compensation using embedded FRA
CN116961415A (en) Switching power supply, direct current power supply system and control method of switching power supply
CN113765414A (en) Wide-output ACDC conversion circuit and control method
JP5894870B2 (en) Solar power system
CN114513132B (en) Isolation half-bridge converter and modeling and loop parameter design method thereof
Pahlevaninezhad et al. An optimal Lyapunov-based control strategy for power factor correction AC/DC converters applicable to electric vehicles
CN112701890B (en) Device for reducing DC output low-frequency ripple

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