LCC resonant converter

Abstract

The utility model discloses an LCC resonant converter, relates to the technical field of power electronics, and solves the problem that an existing device cannot further guarantee electric energy conversion efficiency and output stability and still needs to be solved at present. The device comprises a switch circuit module, a resonance network module, a detection control module and a compensation module, the resonance network module is connected with the switch circuit module, the switch circuit module and the resonance network module are respectively connected with the detection control module, the resonance network module comprises a series branch and a parallel branch, and the series branch is connected with the parallel branch. The series branch comprises an inductor and a first capacitor which are connected in series, the parallel branch comprises a second capacitor, the compensation module comprises a plurality of parallel compensation branches, one compensation branch comprises a redundant capacitor and a switch which are connected in series, the plurality of compensation branches are respectively connected with the second capacitor in parallel, and the redundant capacitor is connected with the switch in parallel. And the plurality of switches are respectively connected with the detection control module. The power supply has the advantages of stable output and the like.

Description

TECHNICAL FIELD

[0001] The utility model belongs to power electronics technical field, concretely relates to a LCC resonant converter. BACKGROUND

[0002] LCC resonant converter is a high frequency soft switching power supply topology, it realizes high efficiency, low loss energy conversion through the resonant characteristic of inductance and capacitance, the core of LCC resonant converter is the design of its resonant network, the network combines the characteristic of series resonance and parallel resonance, it is composed of two capacitors and an inductor, the common topology structure is that the input side series inductance and a capacitor, the output side parallel another capacitor.

[0003] When LCC resonant circuit works under high frequency, the alternating component of resonant current is big to cause the equivalent series resistance of inductance and capacitance to increase, serious Joule heat is produced, the dielectric constant of capacitor dielectric material changes with temperature, causes the capacitance value to deviate, further makes the resonant point deviate and increases switching loss, thereby makes the electric energy conversion efficiency reduce, and the output stability is poor.

[0004] Therefore, in view of the problems existing in the prior art LCC resonant converter, how to further ensure the electric energy conversion efficiency and the output stability is still a problem to be solved at present. UTILITY MODEL CONTENTS

[0005] The utility model provides a kind of LCC resonant converter, it is proposed to solve the problems that the prior art device cannot further ensure the electric energy conversion efficiency and the output stability still is the problem to be solved at present.

[0006] To solve the above-mentioned technical problems, the technical scheme adopted by the present application is as follows:

[0007] A kind of LCC resonant converter, including switching circuit module, resonant network module, detection control module and compensation module,

[0008] The resonant network module is connected with the switching circuit module, and the switching circuit module and the resonant network module are connected with the detection control module,

[0009] The resonant network module includes a series branch and a parallel branch, the series branch includes an inductor and a first capacitor in series, and the parallel branch includes a second capacitor,

[0010] The compensation module includes a plurality of parallel compensation branches, one compensation branch includes a redundant capacitor and a switch in series with each other, and a plurality of the compensation branches are connected with the second capacitor in parallel, and a plurality of the switches are connected with the detection control module.

[0011] In the utility model, when the resonance network module works under high frequency working condition, the second capacitor is easy to produce heat and accumulate, thereby causing the capacitance of the second capacitor to deviate, causing the resonance frequency to be unstable, thereby affecting the stability of the system, and through the parallel redundant capacitor, when the detection control module detects that the current changes, it means that the heat accumulation of the second capacitor causes the capacitance to decrease, according to the change of the current detected by the detection control module, the detection control module controls the switch on the corresponding compensation branch to be closed, thereby accessing the redundant capacitor of the corresponding capacitance, realizing the compensation of the capacitance and improving the stability of the system.

[0012] Preferably, the capacitances of the plurality of parallel redundant capacitors increase in turn, so as to access the appropriate redundant capacitor for compensation when the capacitance of the second capacitor deviates and decreases.

[0013] Preferably, the plurality of parallel compensation branches are a first compensation branch, a second compensation branch and a third compensation branch respectively, the first compensation branch comprises a first switch and a first redundant capacitor in parallel, the second compensation branch comprises a second switch and a second redundant capacitor in parallel, and the third compensation branch comprises a third switch and a third redundant capacitor in parallel.

[0014] Preferably, the detection control module comprises a detection circuit and a controller connected, the detection circuit is connected with the parallel branch, the controller is connected with the switch circuit module and the first switch, the second switch and the third switch respectively, and the controller is a single-chip microcomputer.

[0015] Preferably, the detection circuit comprises an operational amplifier, a resistor and a digital-to-analog conversion module, the operational amplifier is connected with the output end of the parallel branch, the operational amplifier is connected with the digital-to-analog conversion module through the resistor, and the digital-to-analog conversion module is connected with the controller.

[0016] Preferably, the resonance network module is sequentially connected with a transformer, a rectifier filter circuit and a load, the transformer comprises a primary winding and a secondary winding, the primary winding is connected in parallel across the second capacitor, the secondary winding is connected in parallel with the rectifier filter circuit, and the load is connected in parallel with the rectifier filter circuit.

[0017] Preferably, the switch circuit is connected with an input power supply.

[0018] As the above technical scheme is adopted, the utility model has the beneficial effects that:

[0019] The utility model provides a kind of LCC resonant converter, by setting compensation module, when resonant network module works under high frequency condition, detection control module real-time detection the output current of second capacitor, and when current fluctuation, single-chip microcontroller controls the switch of corresponding redundant capacitor to be closed and access, improve the stability of system;Second when second capacitor burst fault, it can also be redundant capacitor compensation, temporarily stabilize system. BRIEF DESCRIPTION OF DRAWINGS

[0020] The utility model will be explained by example and with reference to the drawings, wherein:

[0021] Fig. 1 It is the resonant network module circuit of the utility model;

[0022] Fig. 2 It is the LCC resonant converter circuit of the utility model;

[0023] Fig. 3 It is the overall circuit diagram of the utility model. DETAILED DESCRIPTION

[0024] To make the purpose, technical scheme and advantage of the embodiment of the application more clear, the technical scheme in the embodiment of the application will be clearly and completely described below in conjunction with the embodiment of the application and drawings. Obviously, the described embodiment is only a part of the embodiment of the application, not all. The components of the embodiment of the application described and indicated in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiment of the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0025] In the description of the embodiment of the application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the utility product is used, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second", "third" and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0026] As Figs. 1-3 shown, a kind of LCC resonant converter, including switching circuit module, resonant network module, detection control module and compensation module,

[0027] The resonant network module is connected with the switching circuit module, and the detection control module is connected with the switching circuit module and the resonant network module respectively,

[0028] The resonant network module comprises a series branch and a parallel branch, the series branch comprises an inductor Lr and a first capacitor Cr, and the parallel branch comprises a second capacitor Cp,

[0029] The compensation module comprises a plurality of parallel compensation branches, one compensation branch comprises a redundant capacitor and a switch connected in series with each other, the plurality of compensation branches are connected in parallel with the second capacitor Cp respectively, and the plurality of switches are connected with the detection control module respectively.

[0030] In the embodiment, when the resonant network module works in a high-frequency working condition, the second capacitor Cp is prone to generate heat and accumulate, thereby causing the capacitance of the second capacitor Cp to deviate, resulting in unstable resonant frequency, and thereby affecting the stability of the system. When the detection control module detects a change in current, it means that the heat accumulation of the second capacitor Cp causes the capacitance to decrease. According to the change in current detected by the detection control module, the detection control module controls the switch in the corresponding compensation branch to be closed, thereby connecting the redundant capacitor with the corresponding capacitance, so as to compensate the capacitance and improve the stability of the system.

[0031] In another embodiment, the capacitances of the plurality of parallel redundant capacitors increase in turn, the plurality of parallel compensation branches are a first compensation branch, a second compensation branch and a third compensation branch, the plurality of parallel redundant capacitors are a first redundant capacitor C3, a second redundant capacitor C4 and a third redundant capacitor C5, the switches are field effect tubes, which are a first field effect tube Q3, a second field effect tube Q4 and a third field effect tube Q5, the first redundant capacitor C3 and the first field effect tube Q3 are connected in series to form the first compensation branch, and the subsequent compensation branches are similar to the first compensation branch, the capacitances of the first redundant capacitor C3, the second redundant capacitor C4 and the third redundant capacitor C5 gradually increase, and the capacitance of the third redundant capacitor C5 is less than or equal to the capacitance of the second capacitor Cp, so as to connect the appropriate redundant capacitor to compensate when the capacitance of the second capacitor Cp deviates and decreases.

[0032] In the embodiment, the detection control module comprises a detection circuit and a controller connected with each other, the detection circuit is connected with the output end of the parallel branch, the controller is connected with the switching circuit module and the first field effect tube Q3, the second field effect tube Q4 and the third field effect tube Q5 respectively, and the controller is a single-chip microcomputer with a model of STM32F103C8T6.

[0033] In the embodiment, the switch circuit module is a half-bridge switch circuit, the half-bridge switch circuit comprises an upper switch tube Q1 and a lower switch tube Q2, a drain of the upper switch tube Q1 is connected to a positive pole VCC of an input power supply, a source of the upper switch tube Q1 is connected to a drain of the lower switch tube Q2, a source of the lower switch tube Q2 is connected to a negative pole GND of the input power supply, one end of a series branch is connected to the source of the upper switch tube Q1 and the drain of the lower switch tube Q2, and the other end of the series branch is connected to the source of the lower switch tube Q2, gates of the upper switch tube Q1 and the lower switch tube Q2 are connected to PA1 and PA2 ports of a single-chip microcomputer respectively, gates of a first field effect tube Q3, a second field effect tube Q4 and a third field effect tube Q5 are connected to PA3, PA4 and PA5 ports of the single-chip microcomputer respectively, the upper switch tube Q1, the lower switch tube Q2 and the field effect tubes are MOS tubes, and each of the MOS tubes comprises a body diode and a junction capacitor, and in the first field effect tube Q3, for example, a junction capacitor C6 is connected in parallel across the body diode D7, and by connecting the junction capacitor C6 in parallel, voltage spikes can be effectively reduced and switching characteristics can be improved, the upper switch tube Q1, the lower switch tube Q2 and the field effect tubes have the same structure as the first field effect tube Q1, and are prior art, and will not be described herein.

[0034] In the embodiment, the detection circuit comprises an operational amplifier U1, resistors and a digital-to-analog conversion module, the operational amplifier U1 is connected to an output end of the parallel branch, the operational amplifier U1 is connected to the digital-to-analog conversion module through resistors, and the digital-to-analog conversion module is connected to the controller.

[0035] In the embodiment, the detection circuit comprises an operational amplifier U1, resistors R5, R3, R4 and a capacitor C10, one end of the resistor R5 is connected to an output end of the second capacitor Cp, the other end of the resistor R5 is connected to a non-inverting input end of the operational amplifier U1, an inverting input end of the operational amplifier U1 is connected to an output end of the operational amplifier U1, one end of the resistor R3 is connected to the output end of the operational amplifier U1, the other end of the resistor R3, one end of the resistor R4 and one end of the capacitor C10 are connected to a PA0 port of a single-chip microcomputer, and the other end of the resistor R4 is connected to the other end of the capacitor C10.

[0036] In the embodiment, the resonance network module is sequentially connected to a transformer Tr, a rectification filter circuit and a load R2, the transformer Tr comprises a primary winding and a secondary winding, the primary winding is connected in parallel across the second capacitor Cp, the secondary winding is connected in parallel with the rectification filter circuit, and the load R2 is connected in parallel with the rectification filter circuit.

[0037] In the embodiment, the transformer Tr comprises a primary winding and a secondary winding, the second capacitor Cp is connected in parallel across the primary winding, the rectifying and filtering circuit is composed of diodes D3, D4, D5, D6, an inductor L1 and a capacitor C9, the diodes D3, D4, D5 and D6 are connected in series and then in parallel to form a full-bridge rectifying circuit, which is a prior art and will not be described here, the inductor L1 is connected in series across the output positive pole for suppressing current ripples, the capacitor C9 is connected in parallel between the output positive pole and the output negative pole, i.e. the capacitor C9 is connected in parallel between the output end of the inductor L1 and the negative pole of the full-bridge, for filtering out high-frequency components of the voltage and stabilizing the output voltage; the positive pole of the load R2 is connected to the output end of the inductor L1, and the negative pole of the load R2 is connected to the negative pole of the full-bridge.

[0038] In the embodiment, the switch circuit module is connected to an input power supply.

[0039] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An LCC resonant converter, characterized by, The switching circuit module, the resonance network module, the detection control module and the compensation module are included. The resonance network module is connected with the switching circuit module, and the switching circuit module and the resonance network module are connected with the detection control module respectively. The resonance network module includes a series branch and a parallel branch, the series branch includes an inductor and a first capacitor connected in series, and the parallel branch includes a second capacitor. The compensation module includes a plurality of parallel compensation branches, one compensation branch includes a redundant capacitor and a switch connected in series, the plurality of compensation branches are connected with the second capacitor in parallel respectively, and the plurality of switches are connected with the detection control module respectively.

2. The LCC resonant converter of claim 1, wherein: The capacitance of the plurality of parallel redundant capacitors increases in turn.

3. The LCC resonant converter of claim 1, wherein: The plurality of parallel compensation branches are a first compensation branch, a second compensation branch and a third compensation branch, the first compensation branch includes a first switch and a first redundant capacitor connected in parallel, the second compensation branch includes a second switch and a second redundant capacitor connected in parallel, and the third compensation branch includes a third switch and a third redundant capacitor connected in parallel.

4. The LCC resonant converter of claim 3, wherein: The detection control module includes a detection circuit and a controller connected, the detection circuit is connected with the parallel branch, and the controller is connected with the switching circuit module and the first switch, the second switch and the third switch respectively.

5. The LCC resonant converter of claim 4, wherein: The detection circuit includes an operational amplifier, a resistor and a digital-to-analog conversion module, the operational amplifier is connected with the parallel branch, the operational amplifier is connected with the digital-to-analog conversion module through the resistor, and the digital-to-analog conversion module is connected with the controller.

6. The LCC resonant converter of claim 1, wherein: The resonance network module is connected with a transformer, a rectifier filter circuit and a load in turn, the transformer includes a primary winding and a secondary winding, the primary winding is connected across the second capacitor in parallel, the secondary winding is connected with the rectifier filter circuit in parallel, and the load is connected with the rectifier filter circuit in parallel.

7. A LCC resonant converter according to any one of claims 1-6, characterized in that: The switching circuit is connected with an input power supply.

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