CN216490232U - LLC circuit frequency tracking circuit - Google Patents
LLC circuit frequency tracking circuit Download PDFInfo
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- CN216490232U CN216490232U CN202122176641.0U CN202122176641U CN216490232U CN 216490232 U CN216490232 U CN 216490232U CN 202122176641 U CN202122176641 U CN 202122176641U CN 216490232 U CN216490232 U CN 216490232U
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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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Abstract
The utility model provides a LLC circuit frequency tracking circuit, comprising a direct current power supply, an inverter circuit, a transformer and a rectification circuit; the direct-current power supply is electrically connected with the inverter circuit, one end of the middle point of a bridge arm of the inverter circuit is electrically connected with the resonant inductor Lr, the other end of the middle point of the bridge arm of the inverter circuit is electrically connected with the resonant capacitor Cr, the resonant inductor Lr and the other end of the resonant capacitor Cr are electrically connected with the primary side of the transformer, and the secondary side of the transformer is electrically connected with the rectifying circuit; the current sampling circuit is electrically connected with the control circuit and samples the current I on the primary side of the transformer T; the control circuit is electrically connected with the inverter circuit and the rectifying circuit through the driving circuit. The control circuit outputs PWM drive with gradually increasing frequency according to fixed step length, simultaneously samples primary side current I of a transformer T when the PWM drive is switched off at each frequency point, and sets the driving frequency f at the moment as switching frequency when the primary side current I of the transformer is equal to Iset; the LLC circuit can work near a resonance point when working in forward and reverse directions, and the efficiency is high.
Description
Technical Field
The utility model relates to the technical field of LLC circuits, in particular to an LLC circuit frequency tracking circuit.
Background
With the development of battery charging, a new challenge is provided for a high-efficiency bidirectional battery charging technology, and the working point of an LLC circuit is far away from a resonance point due to the difference between the parameters of a resonance device and the leakage inductance of a transformer in the traditional LLC circuit, so that the efficiency is low.
Disclosure of Invention
Aiming at the defects of the prior art, the utility model provides the LLC circuit frequency tracking circuit, which enables the LLC circuit to work near a resonance point when the LLC circuit works in forward and reverse directions.
The technical scheme of the utility model is as follows: a LLC circuit frequency tracking circuit comprises a direct current power supply VCC, an inverter circuit, a resonant inductor Lr, a resonant capacitor Cr, an excitation inductor Lm, a transformer T, a rectifying circuit, a drive circuit, a control circuit and a current sampling circuit;
the direct current power supply VCC is electrically connected to an inverter circuit, one end of a bridge arm midpoint of the inverter circuit is electrically connected to one end of a resonant inductor Lr, the other end of the bridge arm midpoint of the inverter circuit is electrically connected to one end of a resonant capacitor Cr, the other end of the resonant inductor Lr and the other end of the resonant capacitor Cr are electrically connected to a primary side of a transformer T, and a secondary side TD of the transformer is electrically connected to a rectifier circuit;
the current sampling circuit is electrically connected with the control circuit and samples the current I on the primary side of the transformer T;
the control circuit is electrically connected with the driving circuit, and the driving circuit is electrically connected with the inverter circuit and the rectifying circuit.
Preferably, the inverter circuit includes switches S3, S4, S5, and S6, and positive and negative terminals of the dc power VCC are connected to one terminals of the switches S5, S6, S3, and S4, respectively;
the other ends of the switches S3 and S5 are also electrically connected with the resonant inductor Lr;
the other ends of the switches S4 and S6 are also electrically connected with a resonance capacitor Cr.
Preferably, the rectifier circuit comprises a switch S1 and a switch S2, one end of each of the switch S1 and the switch S2 is electrically connected to the secondary side of the transformer T, and the other end of each of the switch S1 and the switch S2 is connected to the negative pole of Vbat;
the secondary side of the transformer T is also electrically connected with the positive electrode of the Vbat; and a capacitor C is also connected between the anode and the cathode of the Vbat.
Preferably, the current sampling circuit includes but is not limited to hall current sampling, or current transformer sampling, or series resistance sampling, and the current sampling circuit samples the primary side current I of the transformer at each frequency point and transmits the primary side current I to the control circuit.
Preferably, the control circuit is connected after the current sampling circuit, receives the sampling signal, and outputs PWM driving with gradually increasing frequency according to a fixed step length. Preferably, the current sampling circuit sets a threshold current Icset, and when the current sampling circuit detects that the primary current I of the transformer is equal to Icset, the control circuit sends a control signal to set the driving frequency f as the switching frequency.
The utility model has the beneficial effects that:
1. the control circuit outputs PWM drive with gradually increasing frequency according to fixed step length, simultaneously samples primary side current I of a transformer T when the PWM drive is switched off at each frequency point, and sets the driving frequency f at the moment as switching frequency when the primary side current I of the transformer is equal to Iset; the LLC circuit can work near a resonance point when working in forward and reverse directions, and the efficiency is high;
2. the utility model avoids the problems of high switching loss and high stress of the switching tube caused by non-zero current turn-off of the switching tube when the over-frequency work is carried out;
3. the utility model can be realized by only multiplexing the primary side overcurrent protection circuit without adding an additional circuit, and has simple control and low cost.
4、
Drawings
FIG. 1 is a circuit block diagram of the present invention;
FIG. 2 is a circuit diagram of an inverter circuit according to the present invention;
FIG. 3 is a circuit diagram of a rectifier circuit of the present invention;
FIG. 4 is a circuit diagram of a current sampling circuit of the present invention;
FIG. 5 is a circuit diagram of a secondary side driving circuit according to the present invention;
FIG. 6 is a circuit diagram of a primary side drive circuit of the present invention;
Detailed Description
The following further describes embodiments of the present invention with reference to the accompanying drawings:
as shown in fig. 1, the present embodiment provides a LLC circuit frequency tracking circuit, which includes a dc power supply VCC, an inverter circuit, a resonant inductor Lr, a resonant capacitor Cr, an excitation inductor Lm, a transformer T, a rectifier circuit, a driving circuit, a control circuit, and a current sampling circuit; the direct current power supply VCC is electrically connected to an inverter circuit, one end of a bridge arm midpoint of the inverter circuit is electrically connected to one end of a resonant inductor Lr, the other end of the bridge arm midpoint of the inverter circuit is electrically connected to one end of a resonant capacitor Cr, the other end of the resonant inductor Lr and the other end of the resonant capacitor Cr are electrically connected to a primary side of a transformer T, and a secondary side TD of the transformer is electrically connected to a rectifier circuit;
the current sampling circuit is electrically connected with the control circuit and samples the current I on the primary side of the transformer T;
the control circuit is electrically connected with the driving circuit, and the driving circuit is electrically connected with the inverter circuit and the rectifying circuit.
Preferably, as shown in fig. 2, the inverter circuit includes switches S3, S4, S5, and S6, and the positive and negative terminals of the dc power source VCC are connected to one terminals of the switches S5, S6, S3, and S4, respectively;
the other ends of the switches S3 and S5 are also electrically connected with the resonant inductor Lr;
the other ends of the switches S4 and S6 are also electrically connected with a resonance capacitor Cr.
Preferably, as shown in fig. 3, the rectifying circuit includes a switch S1 and a switch S2, one end of each of the switch S1 and the switch S2 is electrically connected to the secondary side of the transformer T, and the other end of each of the switch S1 and the switch S2 is connected to the negative electrode of Vbat;
the secondary side of the transformer T is also electrically connected with the positive electrode of the Vbat; and a capacitor C is also connected between the anode and the cathode of the Vbat.
Preferably, the current sampling circuit includes but is not limited to hall current sampling, or current transformer sampling, or series resistance sampling, and the current sampling circuit samples the primary side current I of the transformer at each frequency point and transmits the primary side current I to the control circuit.
IN this embodiment, as shown IN fig. 4, the current sampling circuit includes a chip INA225AQDGKRQ1, wherein input terminals VO1 and VO2 are connected to an "IN +" terminal and an "IN-" terminal of the chip INA225AQDGKRQ1, the "REF" terminal is connected to a reference voltage of 1.65V, a "GND" terminal, a "GS 0" terminal, and a "GS 1" terminal of the chip INA225AQDGKRQ1 are grounded, and a "Vs" terminal of the chip INA225AQDGKRQ1 is connected to a voltage of 5V.
Preferably, the control circuit is connected after the current sampling circuit, receives the sampling signal, and outputs PWM driving with gradually increasing frequency according to a fixed step length. Preferably, the selected control circuit is preferably a Texas Instruments (TI) C2000 series DSP.
Preferably, the current sampling circuit sets a threshold current Icset, and when the current sampling circuit detects that the primary current I of the transformer is equal to Icset, the control circuit sends a control signal to set the driving frequency f as the switching frequency.
Preferably, the driving circuit comprises a primary side driving circuit and a secondary side driving circuit, wherein as shown in fig. 5, the secondary side driving circuit comprises a chip UCC27524AQDRQ1, an "ENBA" terminal, an "ENBB" terminal and a "VDD" terminal of a chip UCC27524AQDRQ1 are connected with a 12V voltage, a "GND" terminal is connected with ground, and an "INA" terminal and an "INB" terminal are respectively connected with a 5VPWM signal, and a 12VPWM signal is output from an "OUTA" terminal and an "OUTB" terminal.
As shown in FIG. 6, the primary side driving circuit comprises a chip SI8233BB-D-IS1, a chip SI8233BB-D-IS1, wherein a voltage of 5V IS connected to a terminal "VDD 1", terminals "VDDA" and "VDDB" are respectively connected to a voltage of 12V, and terminals "GNDA", terminals "GNDB", terminals "GND 1", terminals "DISABLE" and "DT" are respectively grounded. Two 5V PWM signals are respectively input to an input end through a VIA end and a VIB end, and then 12V PWM signals are output at a VOA end and a VOB end.
Preferably, the control circuit is a C2000 series DSP from Texas Instruments (TI).
The foregoing embodiments and description have been presented only to illustrate the principles and preferred embodiments of the utility model, and various changes and modifications may be made therein without departing from the spirit and scope of the utility model as hereinafter claimed.
Claims (8)
1. An LLC circuit frequency tracking circuit is characterized by comprising a direct-current power supply VCC, an inverter circuit, a resonant inductor Lr, a resonant capacitor Cr, an excitation inductor Lm, a transformer T, a rectifying circuit, a driving circuit, a control circuit and a current sampling circuit;
the direct current power supply VCC is electrically connected to an inverter circuit, one end of a bridge arm midpoint of the inverter circuit is electrically connected to one end of a resonant inductor Lr, the other end of the bridge arm midpoint of the inverter circuit is electrically connected to one end of a resonant capacitor Cr, the other end of the resonant inductor Lr and the other end of the resonant capacitor Cr are electrically connected to a primary side of a transformer T, and a secondary side TD of the transformer is electrically connected to a rectifier circuit;
the current sampling circuit is electrically connected with the control circuit and samples the current I on the primary side of the transformer T;
the control circuit is electrically connected with the driving circuit, and the driving circuit is electrically connected with the inverter circuit and the rectifying circuit.
2. The LLC circuit frequency tracking circuit of claim 1, wherein: the inverter circuit comprises switches S3, S4, S5 and S6, wherein the positive end and the negative end of the direct-current power supply VCC are respectively connected with one ends of the switches S5, S6, S3 and S4;
the other ends of the switches S3 and S5 are also electrically connected with the resonant inductor Lr;
the other ends of the switches S4 and S6 are also electrically connected with a resonance capacitor Cr.
3. The LLC circuit frequency tracking circuit of claim 1, wherein: the rectifying circuit comprises a switch S1 and a switch S2, one ends of the switch S1 and the switch S2 are respectively and electrically connected with the secondary side of the transformer T, and the other ends of the switch S1 and the switch S2 are connected with the negative electrode of Vbat;
the secondary side of the transformer T is also electrically connected with the positive electrode of the Vbat; and a capacitor C is also connected between the anode and the cathode of the Vbat.
4. The LLC circuit frequency tracking circuit of claim 1, wherein: the control circuit is connected behind the current sampling circuit, receives the sampling signal and outputs PWM drive with gradually increased frequency according to fixed step length.
5. The LLC circuit frequency tracking circuit of claim 1, wherein: the current sampling circuit is provided with a threshold current Icset, when the current sampling circuit measures that the primary current I of the transformer is equal to the Icset, the control circuit sends a control signal, and the driving frequency f is set as the switching frequency at the moment.
6. The LLC circuit frequency tracking circuit of claim 1, wherein: the current sampling circuit comprises but is not limited to Hall current sampling, or current transformer sampling, or series resistance sampling, and samples the primary side current I of the transformer at each frequency point and transmits the primary side current I to the control circuit.
7. The LLC circuit frequency tracking circuit of claim 1, wherein: the current sampling circuit comprises a chip INA225AQDGKRQ1, wherein input ends VO1 and VO2 are connected to an 'IN +' end and an 'IN-' end of the chip INA225AQDGKRQ1, the 'REF' end is connected to a reference voltage of 1.65V, a 'GND' end, a 'GS 0' end and a 'GS 1' end of the chip INA225AQDGKRQ1 are grounded, and a 'Vs' end of the chip INA225AQDGKRQ1 is connected to a voltage of 5V.
8. The LLC circuit frequency tracking circuit of claim 1, wherein: the driving circuit comprises a primary side driving circuit and a secondary side driving circuit, wherein the secondary side driving circuit comprises a chip UCC27524AQDRQ1, an 'ENBA' end, an 'ENBB' end and a 'VDD' end of a chip UCC27524AQDRQ1 are connected with 12V voltage, a 'GND' end is grounded, 5VPWM signals are respectively connected with an 'INA' end and an 'INB' end, and 12VPWM signals are output from an 'OUTA' end and an 'OUTB' end;
the primary side driving circuit comprises a chip SI8233BB-D-IS1, a 'VDD 1' end of the chip SI8233BB-D-IS1 IS connected with a voltage of 5V, and a 'VDDA' end and a 'VDDB' end are respectively connected with a voltage of 12V, a 'GNDA' end, a 'GNDB' end, a 'GND 1' end, a 'DISABLE' end and a 'DT' end are respectively grounded; two 5V PWM signals are respectively input into an input end through a VIA end and a VIB end, and then 12V PWM signals are output at a VOA end and a VOB end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122176641.0U CN216490232U (en) | 2021-09-09 | 2021-09-09 | LLC circuit frequency tracking circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122176641.0U CN216490232U (en) | 2021-09-09 | 2021-09-09 | LLC circuit frequency tracking circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216490232U true CN216490232U (en) | 2022-05-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122176641.0U Active CN216490232U (en) | 2021-09-09 | 2021-09-09 | LLC circuit frequency tracking circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216490232U (en) |
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2021
- 2021-09-09 CN CN202122176641.0U patent/CN216490232U/en active Active
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