CN-122001226-A - LLC resonant converter controller, control method and resonant converter

CN122001226ACN 122001226 ACN122001226 ACN 122001226ACN-122001226-A

Abstract

The application relates to an LLC resonant converter controller, a control method and a resonant converter, wherein the LLC resonant converter controller comprises a level shift circuit, a voltage operation circuit, a charge integration circuit, a feedback voltage processing circuit, a comparator and a drive control logic circuit; the level shift circuit receives the resonant current sampling signal and outputs a second voltage signal and a third voltage signal, the voltage operation circuit receives the second voltage signal, the third voltage signal and the input voltage sampling signal and outputs a fifth voltage signal and a sixth voltage signal, the charge integration circuit receives the fifth voltage signal and the sixth voltage signal and outputs a slope voltage signal, the comparator compares the slope voltage with the feedback voltage and outputs a logic control signal, and the drive control logic circuit controls the on-off of a switching tube in the resonant converter. The scheme provided by the application can enable overload protection points of the resonant converter to be basically consistent under different input voltage conditions, and correct and adjust bias voltage in real time so as to enable driving pulse widths to be consistent.

Inventors

DENG TING
ZHAO ZHIWEI
LI YIJIAO

Assignees

广州博之源科技有限公司

Dates

Publication Date: 20260508
Application Date: 20251231

Claims (8)

1. An LLC resonant converter controller, comprising: the device comprises a level shift circuit, a voltage operation circuit, a charge integration circuit, a feedback voltage processing circuit, a comparator and a drive control logic circuit; The level shift circuit receives a first voltage signal representing the magnitude of resonant current of the resonant converter, performs level shift processing, generates a second voltage signal and a third voltage signal representing the magnitude of bias voltage of the second voltage signal, and outputs the output end to the input end of the voltage operation circuit; The input end of the voltage operation circuit also receives a fourth voltage signal representing the magnitude of input voltage, performs correlation operation on the received voltage signal, generates a fifth voltage signal and a sixth voltage signal related to input power, and outputs the fifth voltage signal and the sixth voltage signal to the input end of the charge integration circuit, and the voltage value of the sixth voltage signal is trimmed through bias voltage; The input end of the charge integration circuit is also connected with the output end of the drive control logic circuit, the received fifth voltage signal and the received sixth voltage signal are converted into integrated current, a slope voltage signal is generated, the conversion from power information to a time control signal is realized, and the slope voltage signal is output to the reverse input end of the comparator; the feedback voltage processing circuit converts the output feedback voltage signal into an internal feedback voltage signal, outputs the internal feedback voltage signal to the same-direction input end of the comparator, and outputs a first logic control voltage signal to the drive control logic circuit after the comparator compares the internal feedback voltage signal; The drive control logic circuit outputs a first drive control voltage signal and a second drive control voltage signal, and is used for controlling the on-off of a switching tube in the resonant converter, so that the closed-loop control of the resonant converter is realized.
2. The LLC resonant converter controller of claim 1, wherein: The voltage operation circuit comprises a driving control voltage signal pulse width configuration, and the pulse width deviation of the first driving control voltage signal and the second driving control voltage signal is controlled within a certain range by trimming the bias voltage.
3. The LLC resonant converter controller of claim 1, wherein the voltage operating circuit includes: multiplier M0, multiplier M1, subtractor A0, adder A1, and adder A2; An input end of the multiplier M0 is connected with an input end of the multiplier M1 and then receives a fourth voltage signal representing the input voltage of the resonant converter, the other input end of the multiplier M0 is connected with an output end of the level shift circuit for outputting a second voltage signal, and an output end of the multiplier M0 is connected with an input end of the subtracter A0; The other input end of the multiplier M1 is connected with the output end of the level shift circuit for outputting a third voltage signal, one input end of the adder A1 and one input end of the adder A2, and the output end of the multiplier M1 is connected with the other input end of the subtracter A0; The output end of the subtracter A0 is connected with the other input end of the adder A1, and the output end of the adder A1 outputs a fifth voltage signal to the first input end of the charge integration circuit; the other input end of the adder A2 receives the bias voltage signal Vdc, and the output end of the adder A2 outputs a sixth voltage signal to the second input end of the charge integration circuit.
4. The LLC resonant converter controller of claim 1, wherein the voltage operating circuit includes: multiplier M2, multiplier M3 and adder A3; an input end of the multiplier M2 is connected with an input end of the multiplier M3, and then receives a fourth voltage signal representing the input voltage of the vibration converter, the other input end of the multiplier M2 is connected with an output end of the level shift circuit for outputting a second voltage signal, and the multiplier M2 outputs a fifth voltage signal to a first input end of the charge integration circuit; The other input end of the multiplier M3 is connected with the output end of the level shift circuit for outputting a third voltage signal, the output end of the multiplier M3 is connected with one input end of the adder A3, the other input end of the adder A3 receives the bias voltage signal Vdc, and the output end of the adder A3 outputs a sixth voltage signal to the second input end of the charge integration circuit.
5. A method of controlling an LLC resonant converter, adapted for use in an LLC resonant converter controller according to any of claims 1-4, comprising: Receiving a first voltage signal representing the magnitude of resonant current output by a resonant current sampling circuit, performing level shift processing on the first voltage signal through a level shift circuit, converting an alternating current resonant current signal into a direct current bias signal suitable for subsequent circuit processing, and generating a second voltage signal and a third voltage signal representing the bias voltage magnitude of the second voltage signal; The second voltage signal, the third voltage signal and the fourth voltage signal representing the magnitude of the input voltage are subjected to mathematical operation through a voltage operation circuit, and a fifth voltage signal and a sixth voltage signal are output; Inputting the fifth voltage signal and the sixth voltage signal into a charge integration circuit, performing charge integration processing, converting power information into a time control signal, and outputting a slope voltage signal; Comparing the magnitudes of the slope voltage signal and the internal feedback voltage signal through a comparator, performing real-time comparison and decision of a power state and an output voltage requirement, and outputting a first logic control voltage signal; The driving control logic circuit converts the first logic control voltage signal into a physical driving pulse signal, generates the first driving control voltage signal and the second driving control voltage signal, controls the opening and closing of a driving tube in the resonant converter, and realizes closed-loop control of the resonant converter.
6. The LLC resonant converter control method according to claim 5, wherein the mathematical operation of the second voltage signal, the third voltage signal, and the fourth voltage signal indicative of the magnitude of the input voltage by means of a voltage operation circuit includes: The voltage operation circuit 101 includes a multiplier M0, a multiplier M1, a subtracter A0, an adder A1, and an adder A2; One input end of the multiplier M0 receives the fourth voltage signal UVP, the other input end receives the second voltage signal Vs, and the output end of the multiplier M0 outputs the voltage signal Vs1 to one input end of the subtractor A0, wherein the voltage signal Vs1 is expressed as: Vs1=Vs×UVP(2) Wherein, vs=Va+ -DeltaV, va is a third voltage signal output by the level shift circuit, deltaV=k1×IR, IR is a first voltage signal representing the magnitude of the resonant current of the resonant converter, k1 is a constant, UVP=k2×VIN, k2 is a constant, VIN is the input power supply voltage of the resonant converter; An input end of the multiplier M1 receives the fourth voltage signal UVP, another input end of the multiplier M1 receives the third voltage signal Va, and is connected with an input end of the adder A1 and an input end of the adder A2, an output end of the multiplier M1 outputs the voltage signal Va1 to another input end of the subtractor A0, and the voltage signal Va1 is expressed as: Va1=Va×UVP(3) The output of subtractor A0 outputs a voltage signal Vt to the other input of adder A1, which can be expressed as: Vt=Vs1-Va1(4) Vt=ΔV×UVP(5) The output terminal of A1 of the adder outputs a fifth voltage signal Vn to the first input terminal of the charge integrating circuit, the fifth voltage signal Vn being expressed as: Vn=Va+ΔV×UVP(6) the other end of the adder A2 inputs the bias voltage signal Vdc, and the adder A2 outputs a sixth voltage signal Vp to the charge integrating circuit, the sixth voltage signal Vp being shown as: Vp=Va+Vdc(7) Wherein Vdc is a tunable voltage; Trimming the Vdc voltage to make the voltage value of the output sixth voltage signal Vp of the adder A2 greater than, less than or equal to the voltage value of the fifth voltage signal Vn; From the formulae (6), (7): Vn-Vp=ΔV×UVP-Vdc(8) If the deviation of the pulse width of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL is within a reasonable range, vdc=0v can be obtained without adjusting the pulse width of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL: Vn-Vp=ΔV×UVP(9) When the pulse width of the first driving control voltage signal GH is larger than the pulse width of the second driving control voltage signal GL, the voltage of Vp is reduced by trimming the voltage of Vdc, the deviation of the pulse width of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL is reduced, and when the pulse widths of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL are basically consistent, the voltage of Vp is kept unchanged at the moment; If the pulse width of the first driving control voltage signal GH is smaller than that of the second driving control voltage signal GL, the voltage of Vp is raised by trimming the voltage Vdc, the deviation between the pulse width of the first driving control voltage signal GH and that of the second driving control voltage signal GL is reduced, and when the pulse widths are basically consistent, the Vp voltage is kept unchanged.
7. The LLC resonant converter control method according to claim 5, wherein the mathematical operation of the second voltage signal, the third voltage signal, and the fourth voltage signal indicative of the magnitude of the input voltage by means of a voltage operation circuit includes: the voltage operation circuit comprises a multiplier M2, a multiplier M3 and an adder A3; one input end of the multiplier M2 receives the fourth voltage signal UVP, the other input end of the multiplier M2 receives the second voltage signal Vs, the multiplier M2 outputs the fifth voltage signal Vn to the first input end of the charge integrating circuit 102, and the output fifth voltage signal Vn is expressed as: Vn=Vs×UVP(10) Vn=(Va+ΔV)×UVP(11) one input end of the multiplier M3 receives the fourth voltage signal UVP, the other input end of the multiplier M3 receives the third voltage signal Va, and the output signal Va2 of the multiplier M3 is expressed as: Va2=Va×UVP(12) The output end of the multiplier M3 is connected to one end of the adder A3, the other end of the adder A3 receives the bias voltage signal Vdc, and the output end of the adder A3 outputs a sixth voltage signal Vp to the second input end of the charge integration circuit 102, where the sixth voltage signal Vp is expressed as: Vp=Va2+Vdc(13) vp can be obtained from the formulas (12) and (13): Vp=Va×UVP+Vdc(14) Wherein Vdc is a tunable voltage; trimming Vdc voltage to make the voltage value of sixth voltage signal Vp output from adder A3 greater than, less than or equal to the voltage value of fifth voltage signal Vn; from formulae (11) - (14): Vn-Vp=ΔV×UVP-Vdc(15) If the deviation of the pulse width of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL is within a reasonable range, vdc=0v can be obtained without adjusting the pulse width of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL: Vn-Vp=ΔV×UVP(16) when the pulse width of the first driving control voltage signal GH is larger than the pulse width of the second driving control voltage signal GL, the voltage of Vdc is modified to reduce the voltage of Vp, the deviation between the pulse width of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL is reduced, and when the pulse widths of the first driving control voltage signal GH and the pulse width of the second driving control voltage signal GL are basically consistent, the voltage of Vp is fixed to be unchanged at the moment; if the pulse width of the first driving control voltage signal GH is smaller than that of the second driving control voltage signal GL, the Vp voltage starts to rise by trimming the voltage Vdc, the deviation between the pulse width of the first driving control voltage signal GH and that of the second driving control voltage signal GL is reduced, and when the pulse widths are basically consistent, the Vp voltage is kept unchanged.
8. A resonant converter, characterized by: a resonant converter comprising an LLC resonant converter controller employing any of claims 1 to 4, the resonant converter being a half-bridge resonant converter or a full-bridge resonant converter.

Description

LLC resonant converter controller, control method and resonant converter Technical Field The application relates to the technical field of LLC resonant converters, in particular to an LLC resonant converter controller, a control method and a resonant converter. Background The LLC resonant converter has the advantages of simple structure, high efficiency, soft switch support, high power density and the like, and is widely applied to occasions such as photovoltaic power generation, communication power supply, vehicle-mounted power supply and the like. In practical application, the traditional LLC resonant converter has the advantages of narrow working frequency range and limited voltage gain adjustment capability, so that the traditional LLC resonant converter is difficult to stably work under the condition of wide input voltage, poor consistency of driving signal pulse width, easy to cause asymmetrical conduction time of upper and lower pipes of a half bridge or a full bridge, drift of overload protection points along with input voltage change, inconsistent over-power protection during high-voltage or low-voltage input, and influence on system reliability. In the prior art, a Pulse Width Modulation (PWM) and Pulse Frequency Modulation (PFM) hybrid control strategy or a phase shift control scheme is mostly adopted, so that the resonant converter can stably work in a wide input voltage range. The problems of asymmetric driving pulse width and inconsistent overpower points are not solved, so that when the input voltage is greatly changed, the system can still have protection function abnormality, efficiency reduction or magnetic bias phenomenon, and the application of the resonant converter in high-reliability occasions is restricted. Therefore, there is a need for an LLC resonant converter controller and control scheme that can maintain the consistency of the overpower point over a wide input voltage range, and dynamically tune the drive pulse width symmetry, thereby improving the stability and reliability of the resonant converter. Disclosure of Invention In order to solve or partially solve the problems existing in the related art, the application provides an LLC resonant converter control method, a controller and a resonant converter, and aims to solve the problems of asymmetrical driving pulse width and inconsistent overpower points of the resonant converter. A first aspect of the application provides an LLC resonant converter controller comprising: the device comprises a level shift circuit, a voltage operation circuit, a charge integration circuit, a feedback voltage processing circuit, a comparator and a drive control logic circuit; The input end of the level shift circuit receives a first voltage signal representing the magnitude of the resonant current of the resonant converter, performs level shift processing on the first voltage signal, generates a second voltage signal and a third voltage signal representing the magnitude of the bias voltage of the second voltage signal, and the output end of the level shift circuit is connected with the input end of the voltage operation circuit; The input end of the voltage operation circuit also receives a fourth voltage signal representing the magnitude of input voltage, performs mathematical operation on the received second voltage signal, third voltage signal and fourth voltage signal to generate a fifth voltage signal and a sixth voltage signal, and the output end of the voltage operation circuit is connected with the input end of the charge integration circuit; the input end of the charge integration circuit is also connected with the output end of the drive control logic circuit, the received fifth voltage signal and the received sixth voltage signal are converted into integrated currents, the integrated currents are used for capacitor charging to generate slope voltage signals, and the charge integration circuit outputs the slope voltage signals to the reverse input end of the comparator; The input end of the feedback voltage processing circuit receives an output feedback voltage signal, converts the received output feedback voltage signal into an internal feedback voltage signal, outputs the internal feedback voltage signal to the same-direction input end of the comparator, and outputs a first logic control voltage signal to the input end of the drive control logic circuit after the comparator compares the internal feedback voltage signal; the first output end of the drive control logic circuit outputs a first drive control voltage signal, and the second output end outputs a second drive control voltage signal. Optionally, the voltage operation circuit includes a pulse width configuration of the driving control voltage signal, and the pulse width deviation of the first driving control voltage signal and the second driving control voltage signal is controlled within a certain range by trimming the bias voltage. Optionally, the voltage operation circuit in