CN213585580U

CN213585580U - III type compensation circuit for improving large dynamic response of LLC resonant converter

Info

Publication number: CN213585580U
Application number: CN202022257371.1U
Authority: CN
Inventors: 杨新华; 朱伟贵
Original assignee: Zhuzhou Megmeet Electric Co ltd
Current assignee: Zhuzhou Megmeet Electric Co ltd
Priority date: 2020-10-12
Filing date: 2020-10-12
Publication date: 2021-06-29
Anticipated expiration: 2030-10-12

Abstract

The utility model discloses a III type compensating circuit for improving the large dynamic response of an LLC resonant converter, which comprises an operational amplifier, a first module and a second module, wherein the first module is connected with the reverse input end of the operational amplifier in series, and the second module is connected between the reverse input end and the output end of the operational amplifier in parallel; the first module comprises a first resistor R1 and a first capacitor C1 which are connected in series with each other, and a second resistor R2 which is connected with the first resistor R1 and the first capacitor C1 in parallel; the second module comprises a third resistor R3 and a second capacitor C2 which are connected in series with each other, a third capacitor C3 which is connected with the third resistor R3 and the second capacitor C2 in parallel, and a third module for overflow feedback, wherein the third module is connected between the inverting input end and the output end of the operational amplifier in parallel or connected with two ends of the first module in parallel. The utility model discloses an improve LLC resonant converter big dynamic response's III type compensating circuit has simple and practical, effectively reduces advantages such as overshoot and recovery time.

Description

III type compensation circuit for improving large dynamic response of LLC resonant converter

Technical Field

The utility model relates to a power electronics technical field especially relates to an improve III type compensating circuit of big dynamic response of LLC resonant converter.

Background

An LLC resonant converter, as a commonly used DC/DC topology, adjusts the magnitude of output voltage by changing the switching frequency, and the system is usually set to be in an intermittent operation state when no-load output is provided. When the load is light or no-load, the frequency of the system is high or in an intermittent wave-sending mode, and when the load is added from no-load to full-load, the output voltage overshoot is large and the recovery time is long.

Fig. 1 shows a type III compensation circuit of a currently-used LLC resonant converter, which has a good effect on a steady state and a loop, but the effect is not ideal when a load has a large dynamic change, and especially when a wide voltage output is provided, the dynamic response requirement of the load under multiple voltage conditions cannot be satisfied at the same time.

As shown in fig. 2 and fig. 3, the dynamic waveforms of the load from no load to full load when the LLC resonant converter outputs 24V and 28V based on the existing type III compensation circuit are tested, and as can be seen from fig. 2, when the system outputs 24V, the overshoot amount is 1.17/24-4.88%, and the recovery time is 0.8 ms; it can be seen from fig. 3 that when the system outputs 28V, the overshoot amount is 1.21/28-4.32%, the recovery time is 1.15ms, and there is about 3-4 cycles of oscillation. It can be seen that when such a type III compensation circuit is used, the response effect of large dynamic changes is not very good, particularly in terms of large overshoot and long recovery time.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to overcome prior art not enough, provide a simple and practical, effectively reduce overshoot and recovery time's the big dynamic response's of improvement LLC resonant converter type III compensating circuit.

In order to solve the technical problem, the utility model provides a technical scheme does:

a III-type compensation circuit for improving large dynamic response of an LLC resonant converter comprises an operational amplifier, a first module and a second module, wherein the first module is connected with the reverse input end of the operational amplifier in series, and the second module is connected between the reverse input end and the output end of the operational amplifier in parallel; the first module comprises a first resistor R1 and a first capacitor C1 which are connected in series with each other, and a second resistor R2 which is connected with the first resistor R1 and the first capacitor C1 in parallel; the second module comprises a third resistor R3 and a second capacitor C2 which are connected in series with each other, a third capacitor C3 which is connected with the third resistor R3 and the second capacitor C2 in parallel, and a third module for overflow feedback, wherein the third module is connected between the inverting input end and the output end of the operational amplifier in parallel or connected with two ends of the first module in parallel.

As a further improvement of the above technical solution:

the third module is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier, and comprises a first transistor D1 and a fourth resistor R4 which are connected in series, wherein the anode of the first transistor D1 is connected with the output terminal of the operational amplifier.

The third module is connected between the reverse input end and the output end of the operational amplifier in parallel, and comprises a voltage regulator tube Z1 and a fourth resistor R4 which are connected in series, wherein the negative electrode of the voltage regulator tube Z1 is connected with the output end of the operational amplifier.

The third module is connected in parallel to two ends of the first module, the third module comprises a first series assembly formed by connecting a fourth resistor R4 and a first transistor D1 in series, a second series assembly formed by connecting a fifth resistor R5 and a second transistor D2 in series, and a fourth capacitor C4, the first series assembly and the second series assembly are connected in parallel and then connected in series with the fourth capacitor C4 to form the third module, wherein opposite poles of the first transistor D1 and the second transistor D2 are connected.

Compared with the prior art, the utility model has the advantages of:

the utility model discloses an improve LLC resonant converter big dynamic response's III type compensating circuit, on current III type compensating circuit's basis, a third module has parallelly connected between operational amplifier's reverse input end and output, or a third module of parallelly connected at the both ends of first module, this third module can spill over the feedback, consequently when the load increases, can adjust in a flexible way, make operational amplifier's output voltage state such as saturation can not appear, thereby response speed has been accelerated, and then reduce output voltage's overshoot, the recovery time has been accelerated, overshoot is big when having solved the big dynamic change of load and the long problem of recovery time, the degree of difficulty of loop parameter debugging has also been reduced simultaneously.

Drawings

FIG. 1 is a schematic diagram of a conventional type III compensation circuit;

FIG. 2 is a dynamic waveform from no load to full load at 24V output of a prior art LLC resonant converter;

FIG. 3 is a dynamic waveform from no load to full load at 28V output for a prior art LLC resonant converter;

FIG. 4 is a schematic configuration diagram of a type III compensation circuit of embodiment 1;

FIG. 5 is a dynamic waveform from no load to full load at 24V output of an LLC resonant converter employing the type III compensation circuit of embodiment 1;

FIG. 6 is the dynamic waveform from no load to full load at 28V output of LLC resonant converter using the type III compensation circuit of embodiment 1

FIG. 7 is a schematic configuration diagram of a type III compensation circuit of embodiment 2;

fig. 8 is a schematic configuration diagram of a type III compensation circuit of embodiment 3.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully and specifically with reference to the accompanying drawings and preferred embodiments, but the scope of the present invention is not limited to the following specific embodiments.

Example 1:

as shown in fig. 4, the III-type compensation circuit for improving the large dynamic response of the LLC resonant converter of this embodiment includes an operational amplifier, a first module and a second module, the first module is connected in series with the inverting input terminal of the operational amplifier, and the second module is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier; the first module comprises a first resistor R1 and a first capacitor C1 which are connected in series with each other, and a second resistor R2 which is connected with the first resistor R1 and the first capacitor C1 in parallel; the second module comprises a third resistor R3 and a second capacitor C2 which are connected in series with each other, and a third capacitor C3 which is connected in parallel with the third resistor R3 and the second capacitor C2. The inverting input end of the operational amplifier is connected with the voltage value Vo sampled by the voltage division network through the first module, and the forward input end of the operational amplifier is connected with a reference voltage VDC1 with the amplitude of 2.5V.

In addition, on the basis of the existing type III compensation circuit, the third module for overflowing feedback is connected in parallel between the reverse input end and the output end of the operational amplifier, so that when the load is increased, the regulation can be flexibly performed, the output voltage of the operational amplifier cannot be in saturation and other states, the response speed is accelerated, the overshoot of the output voltage is reduced, the recovery time is accelerated, the problems of large overshoot and long recovery time during large dynamic change of the load are solved, and the difficulty in debugging the loop parameters is reduced.

The third module in this embodiment includes a first transistor D1 and a fourth resistor R4 connected in series, and the anode of the first transistor D1 is connected to the output terminal of the operational amplifier, so that the output terminal of the operational amplifier is fed back to the inverting input terminal through the first transistor D1 and the fourth resistor R4. The III type compensation circuit of the embodiment is small in change, the operation implementation process is simple and convenient, and the improvement of the system performance can be realized through simple transformation.

As shown in fig. 5, when the LLC resonant converter outputs at 24V, the type III compensation circuit of the present embodiment is adopted, so that the overshoot amount of the load is 1.17/24 to 3.38% during the load from no load to full load, the recovery time is 0.7ms, the overshoot amount is reduced by 1.5% compared with the previous one, and the recovery time is reduced by 0.1 ms.

As shown in fig. 6, when the LLC resonant converter outputs at 28V, the type III compensation circuit of the present embodiment is used, so that the overshoot of the load is 3.07% from no load to full load, the recovery time is 0.5ms, the overshoot is reduced by 1.25% compared to the previous one, and the recovery time is reduced by 0.65 ms.

Therefore, it can be seen that the type III compensation circuit of the present embodiment improves overshoot and recovery time of different output voltages to different degrees, thereby improving dynamic response performance of the system and enabling the system to stably operate under different dynamic conditions.

In this embodiment, the operational amplifier is LM2904A, the first resistor R1 is 1.5k Ω, the second resistor R2 is 24k Ω, the third resistor R3 is 5.1k Ω, and the fourth resistor R4 is 100k Ω; the first capacitor C1 is 4700pF, the second capacitor C2 is 0.022uF, the third capacitor C3 is 100pF, and the first transistor D1 is 1N4148 WS. In other embodiments, the size and model of each component may also be adaptively changed according to the use situation, which is not described herein.

Example 2:

this embodiment is substantially the same as embodiment 1, except that, as shown in fig. 7, in this embodiment, a third module is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier, and the third module includes a voltage regulator tube Z1 and a fourth resistor R4 connected in series with each other, where a negative electrode of the voltage regulator tube Z1 is connected to the output terminal of the operational amplifier. The zener tube Z1 stabilizes the voltage by its reverse breakdown characteristic and can achieve substantially the same effect as embodiment 1.

Example 3:

this embodiment is substantially the same as embodiment 1, except that, as shown in fig. 8, in this embodiment, a third module is connected in parallel to two ends of the first module, the third module includes a first series component formed by connecting a fourth resistor R4 and a first transistor D1 in series, a second series component formed by connecting a fifth resistor R5 and a second transistor D2 in series, and a fourth capacitor C4, the first series component is connected in parallel with the second series component and then connected in series with a fourth capacitor C4 to form the third module, wherein opposite poles of the first transistor D1 and the second transistor D2 are connected. When the load suddenly changes from no load to full load, the voltage value Vo sampled by the voltage division network drops, if the dropped voltage exceeds 0.3V (germanium diode), the second transistor D2 is turned on, and the change of the output voltage can be improved through the fifth resistor R5 and the fourth capacitor C4; when the load suddenly goes from full load to no load, Vo will rise, and if the rising voltage exceeds 0.3V (germanium diode), the first transistor D1 is turned on, and the variation of the output voltage can be improved through the fourth resistor R4 and the fourth capacitor C4.

The above description is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, the modifications and changes obtained without departing from the technical idea of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A III-type compensation circuit for improving large dynamic response of an LLC resonant converter comprises an operational amplifier, a first module and a second module, wherein the first module is connected with the reverse input end of the operational amplifier in series, and the second module is connected between the reverse input end and the output end of the operational amplifier in parallel; the first module comprises a first resistor R1 and a first capacitor C1 which are connected in series with each other, and a second resistor R2 which is connected with the first resistor R1 and the first capacitor C1 in parallel; the second module comprises a third resistor R3 and a second capacitor C2 which are connected in series with each other, and a third capacitor C3 which is connected with the third resistor R3 and the second capacitor C2 in parallel, and is characterized in that: the third module is connected in parallel between the inverting input end and the output end of the operational amplifier or connected in parallel at two ends of the first module.

2. The type III compensation circuit for improving large dynamic response of LLC resonant converter according to claim 1, characterized in that: the third module is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier, and comprises a first transistor D1 and a fourth resistor R4 which are connected in series, wherein the anode of the first transistor D1 is connected with the output terminal of the operational amplifier.

3. The type III compensation circuit for improving large dynamic response of LLC resonant converter according to claim 1, characterized in that: the third module is connected between the reverse input end and the output end of the operational amplifier in parallel, and comprises a voltage regulator tube Z1 and a fourth resistor R4 which are connected in series, wherein the negative electrode of the voltage regulator tube Z1 is connected with the output end of the operational amplifier.

4. The type III compensation circuit for improving large dynamic response of LLC resonant converter according to claim 1, characterized in that: the third module is connected in parallel to two ends of the first module, the third module comprises a first series assembly formed by connecting a fourth resistor R4 and a first transistor D1 in series, a second series assembly formed by connecting a fifth resistor R5 and a second transistor D2 in series, and a fourth capacitor C4, the first series assembly and the second series assembly are connected in parallel and then connected in series with the fourth capacitor C4 to form the third module, wherein opposite poles of the first transistor D1 and the second transistor D2 are connected.