Efficient boost chopper circuit

Abstract

The utility model relates to a high-efficiency boost chopper circuit, and belongs to the field of DC boost circuits. The high-efficiency boost chopper circuit comprises an energy conversion branch circuit, an energy storage branch circuit, a first switch branch circuit, a second switch branch circuit and a pulse width modulation chip, and the first switch branch circuit and the second switch branch circuit are controlled and connected through the pulse width modulation chip, so that the first switch branch circuit and the second switch branch circuit can be alternately connected and conducted. Therefore, the reaction time of waiting for the conduction of the diode after the first switch tube in the existing boost chopper circuit is turned off is avoided, the charging preparation time of the output filter capacitor is shortened, and the forward conduction voltage drop of the metal oxide semiconductor field effect transistor replacing the diode is obviously reduced compared with the conduction voltage drop of the diode. Therefore, the power loss in the boost conversion process of the boost chopper circuit can be remarkably reduced, and finally the boost conversion efficiency, namely the working efficiency, of the boost chopper circuit is remarkably improved.

Description

Technical Field

[0001] The utility model relates to the field of DC boost circuits, and particularly relates to an efficient boost chopper circuit. Background Art

[0002] The boost chopper circuit is one of the six basic chopper circuits and is a switched DC boost circuit. It can make the output voltage higher than the input voltage, thereby realizing the adjustment of the voltage to meet the equipment's demand for a higher voltage and ensuring the normal operation of the equipment.

[0003] Since the boost chopper circuit has simple control and low cost, it is widely used in electronic devices, photovoltaic power generation, wireless communication, and automotive electronics. Therefore, the working efficiency of the boost chopper circuit, that is, the boost conversion efficiency, directly affects the operating efficiency of the equipment or the working system where it is located. Therefore, how to further improve the working efficiency of the existing boost chopper circuit has become an urgent problem to be solved. Summary of the Utility Model

[0004] In view of the above technical problems, the utility model provides an efficient boost chopper circuit to solve the problem of how to further improve the working efficiency of the existing boost chopper circuit.

[0005] In a first aspect, the utility model provides an efficient boost chopper circuit, including: an energy conversion branch, an energy storage branch, a first switch branch, a second switch branch, and a pulse width modulation chip. The input end of the efficient boost chopper circuit is connected to the input end of the energy conversion branch. The output end of the energy conversion branch is connected to the input end of the first switch branch and the input end of the second switch branch. The output end of the first switch branch is grounded. The output end of the second switch branch is connected to the output end of the efficient boost chopper circuit and the input end of the energy storage branch. The output end of the energy storage branch is grounded. The pulse width modulation chip is controllably connected to the first switch branch and the second switch branch.

[0006] Optionally, the second switch branch includes a metal oxide semiconductor field effect transistor, and the first control output end of the pulse width modulation chip is connected to the gate of the metal oxide semiconductor field effect transistor.

[0007] Optionally, the energy conversion branch includes an inductor.

[0008] Optionally, the inductor is an iron core inductor.

[0009] Optionally, the energy storage branch includes an energy storage capacitor.

[0010] Optionally, the energy storage capacitor is a polarized capacitor. The positive electrode of the polarized capacitor is connected to the input end of the energy storage branch, and the negative electrode of the polarized capacitor is connected to the output end of the energy storage branch.

[0011] Optionally, an input filter branch is further included. The input end of the high-efficiency boost chopper circuit is connected to the input end of the input filter branch, and the output end of the input filter branch is grounded.

[0012] Optionally, the input filter branch includes an input filter capacitor.

[0013] Optionally, the input filter capacitor is a non-polarized capacitor.

[0014] Optionally, the first switch branch includes a controllable switch. The second control output end of the pulse width modulation chip is connected to the control end of the controllable switch.

[0015] The above solution has the following beneficial effects:

[0016] The high-efficiency boost chopper circuit of the present utility model includes an energy conversion branch, an energy storage branch, a first switch branch, a second switch branch, and a pulse width modulation chip. By controlling the connection of the first switch branch and the second switch branch through the pulse width modulation chip, the first switch branch and the second switch branch can be alternately connected and conducted, so as to avoid the reaction time required for the diode to conduct after the first switch tube in the existing boost chopper circuit is turned off and cut off, shorten the charging preparation time for the output filter capacitor, and since the forward conduction voltage drop of the metal oxide semiconductor field effect transistor replacing the diode is significantly smaller than the conduction voltage drop of the diode, the power loss during the boost conversion process of the boost chopper circuit can be significantly reduced, and finally the boost conversion efficiency of the boost chopper circuit, that is, the working efficiency, can be significantly improved. Description of the Drawings

[0017] Figure 1 is the circuit diagram of the existing boost chopper circuit;

[0018] Figure 2 is the circuit diagram of the high-efficiency boost chopper circuit provided in an embodiment of the present utility model. Detailed Embodiments

[0019] In order to make the technical problems, technical solutions, and beneficial effects solved by the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments.

[0020] It should be understood that the embodiments described below represent the necessary information enabling those skilled in the art to implement the embodiments and illustrate the best mode of implementing the embodiments. After reading the following description with reference to the drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications thereof not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of the present disclosure and the appended claims.

[0021] It should also be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element, without departing from the scope of the present disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0022] It should also be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. In contrast, when an element is referred to as "directly connected" or "directly coupled" to another element, there are no intermediate elements.

[0023] It should also be understood that terms such as "upper", "lower", "left", "right", "front", "rear", "bottom", "middle", "center", "top", etc. may be used herein to describe various elements, and the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, these elements should not be limited by these terms.

[0024] These terms are only used to distinguish one element from another. For example, the first element may be referred to as the "upper" element, and similarly, the second element may be referred to as the "upper" element according to the relative orientation of these elements, without departing from the scope of the present disclosure.

[0025] It is further understood that the terms "comprise", "comprising", "include" and / or "including" when used herein specify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0026] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0027] In one embodiment, there is provided a high-efficiency boost chopper circuit as shown in Figure 2 which is improved on the basis of the existing boost chopper circuit shown in Figure 1 Therefore, the existing boost chopper circuit will be introduced first.

[0028] The existing boost chopper circuit is as shown in Figure 1 The working process is as follows: First, the pulse width modulation chip (PWM IC) controls the switch tube to conduct. At this time, one end of the inductor is connected to the input voltage Vi on the input filter capacitor, and the other end is grounded through the switch tube. Since the anode of the diode is also grounded through the switch tube at this time, there is no voltage on the diode to satisfy its conduction, so the diode is in the cut-off state, and the input voltage Vi charges the inductor. Subsequently, the pulse width modulation chip controls the switch tube to cut off. At this time, the diode conducts under the combined action of the input voltage Vi and the voltage VL on the inductor. The input voltage Vi and the voltage VL on the inductor jointly charge the output filter capacitor connected in parallel with the load RL and supply power to the load RL at the same time. The pulse width modulation chip repeats the control process of turning the switch tube on and off, and the charging of the output filter capacitor can be completed. And because the charging process of the output filter capacitor is jointly completed by the input voltage Vi and the voltage VL on the inductor, the voltage Vo on the output filter capacitor can be greater than the input voltage Vi, thus completing the boost.

[0029] From the above introduction of the working process of the existing boost chopper circuit, it can be seen that during the process of completing the boost output, it is necessary to frequently repeat the control process of turning the switch tube on and off. And in each control process, it is necessary to charge the output filter capacitor through the diode to maintain the output voltage Vo. Since there is a voltage drop on the diode when it conducts, it is easy to understand that there is a voltage on the diode and there must also be a current during the process of charging the output filter capacitor. Then, there must be power loss on the diode during the process of charging the output filter capacitor. At the same time, the conduction process of the diode also requires a response time. Therefore, in the boost conversion process of the existing boost chopper circuit, there is power waste due to the existence of the diode, and because it is a passive device, that is, after the switch tube is turned off and a voltage is generated on it, it will conduct after a certain time after the switch tube is turned off. Therefore, the charging process of the output filter capacitor requires additional waiting time.

[0030] In summary, due to the on-state voltage drop and on-time of the diode in the existing boost chopper circuit, the working efficiency of the existing boost chopper circuit, that is, the boost conversion efficiency, is relatively low.

[0031] In view of the above reasons affecting the boost conversion efficiency of the boost chopper circuit, in this embodiment, an improved high-efficiency boost chopper circuit as shown in Figure 2 is obtained on the basis of the existing boost chopper circuit. It includes an energy conversion branch, an energy storage branch, a first switch branch, a second switch branch, and a pulse width modulation chip. In this embodiment, it is preferably that the energy conversion branch includes an inductor. In other embodiments, in order to improve the energy conversion efficiency, the inductor can be further preferably an iron core inductor. The input end of the high-efficiency boost chopper circuit is connected to the input end of the energy conversion branch. The output end of the energy conversion branch is connected to the input ends of the first switch branch and the second switch branch. In this embodiment, it is preferably that the first switch branch includes a first controllable switch Q1, and the second switch branch includes a second controllable switch Q2. The output end of the first switch branch is grounded. The output end of the second switch branch is connected to the output end of the high-efficiency boost chopper circuit and the input end of the energy storage branch. The output end of the energy storage branch is grounded. In this embodiment, it is preferably that the energy storage branch includes an energy storage capacitor. In other embodiments, in order to improve the energy storage capacity of the energy storage branch, the energy storage capacitor can be further preferably a polarized capacitor, and the positive electrode of the polarized capacitor is connected to the input end of the energy storage branch, and the negative electrode is connected to the output end of the energy storage branch. The pulse width modulation chip is controlled to be connected to the first switch branch and the second switch branch. Specifically, the control end of the second controllable switch Q2 in the second switch branch is connected through the first control output end, and the control end of the first controllable switch Q1 in the first switch branch is connected through the second control output end.

[0032] It should be noted that since the input filter capacitor C1 does not play a role in energy transmission and storage directly related to boosting, the circuit structure in this embodiment actually does not include the input filter capacitor C1 as shown in Figure 2 Considering that the function of the input filter capacitor C1 is to smooth the input voltage, in other embodiments, in order to achieve smoothing of the input voltage, the high-efficiency boost chopper circuit can further include an input filter branch. The input end of the high-efficiency boost chopper circuit is connected to the input end of the input filter branch, and the output end of the input filter branch is grounded. Specifically, in one embodiment, the input filter branch can be composed of the input filter capacitor C1 as shown in Figure 2 Considering better smoothing in such a high-frequency circuit of the boost chopper circuit, the input filter capacitor C1 can be further preferably a non-polar capacitor.

[0033] During the operation of this high-efficiency boost chopper circuit, as shown in Figure 2As shown, since the pulse width modulation chip controls the pulse timings of the first controllable switch Q1 and the second controllable switch Q2 to be opposite, that is, when controlling the first controllable switch Q1 to conduct, the second controllable switch Q2 is simultaneously controlled to cut off, alternately controlling the conduction of the first switching tube Q1 and the second switching tube Q2. By controlling the conduction and cut-off of the second switching tube Q2 through the pulse width modulation chip, the diode in the existing boost chopper circuit is replaced. And through this active control of the pulse width modulation chip, the conduction moment of the second switching tube Q2 can be made the same as the cut-off moment of the first switching tube Q1. Compared with the passive conduction of the diode in the existing boost chopper circuit, the waiting time for the diode to conduct in the existing boost chopper circuit is avoided, and time can be saved to a certain extent, thereby improving the boost conversion efficiency.

[0034] Furthermore, in another embodiment, the type of the second switching tube Q2 is specifically defined as a metal oxide semiconductor field effect transistor. The reason for such selection is that the conduction voltage drop of the power diode used in the current boost chopper circuit is basically a fixed value. The types of power diodes generally include silicon tubes, whose conduction voltage drop is about 0.7 - 1.0V, and also include Schottky tubes, whose conduction voltage drop is about 0.4 - 0.5V. While the forward conduction voltage drop of the power MOS tube, that is, the metal oxide semiconductor field effect transistor, can be significantly lower than the conduction voltage drop of the power diode used in the existing boost chopper circuit. Since the conduction voltage drop is significantly reduced, the power loss can be significantly reduced. That is, by defining the type of the second switching tube Q2 as a metal oxide semiconductor field effect transistor, on the basis of the previous embodiment, the boost conversion efficiency of the high-efficiency boost chopper circuit can be further improved by reducing the additional power loss during the charging of the energy storage branch, that is, improving the working efficiency, and finally realizing high-efficiency boost conversion.

[0035] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An efficient boost chopper circuit, characterized in that, Comprising: An energy conversion branch, an energy storage branch, a first switch branch, a second switch branch, and a pulse width modulation chip. The input end of the high-efficiency boost chopper circuit is connected to the input end of the energy conversion branch. The output end of the energy conversion branch is connected to the input end of the first switch branch and the input end of the second switch branch. The output end of the first switch branch is grounded. The output end of the second switch branch is connected to the output end of the high-efficiency boost chopper circuit and the input end of the energy storage branch. The output end of the energy storage branch is grounded. The pulse width modulation chip is controllably connected to the first switch branch and the second switch branch.

2. The high-efficiency boost chopper circuit according to claim 1, wherein The second switch branch includes a metal oxide semiconductor field effect transistor. The first control output end of the pulse width modulation chip is connected to the gate of the metal oxide semiconductor field effect transistor.

3. The high-efficiency boost chopper circuit according to claim 1, wherein The energy conversion branch includes an inductor.

4. The high-efficiency boost chopper circuit according to claim 3, wherein The inductor is an iron core inductor.

5. The high-efficiency boost chopper circuit according to claim 1, wherein The energy storage branch includes an energy storage capacitor.

6. The high-efficiency boost chopper circuit according to claim 5, wherein The energy storage capacitor is a polarized capacitor. The positive electrode of the polarized capacitor is connected to the input end of the energy storage branch, and the negative electrode of the polarized capacitor is connected to the output end of the energy storage branch.

7. The high-efficiency boost chopper circuit according to claim 1, characterized in that, It further includes an input filter branch. The input end of the high-efficiency boost chopper circuit is connected to the input end of the input filter branch, and the output end of the input filter branch is grounded.

8. The high-efficiency boost chopper circuit according to claim 7, wherein The input filter branch includes an input filter capacitor.

9. The high-efficiency boost chopper circuit according to claim 8, wherein The input filter capacitor is a non-polarized capacitor.

10. The high-efficiency boost chopper circuit according to claim 1, wherein The first switch branch includes a controllable switch. The second control output end of the pulse width modulation chip is connected to the control end of the controllable switch.

Images