CN112994449B - Three-state resonant switch capacitor power converter and control method thereof - Google Patents

Abstract

The invention discloses a three-state resonance switched capacitor power converter and a control method thereof, comprising a first flying capacitor, a second flying capacitor and a voltage output terminal. The first flying capacitor is connected to a positive voltage terminal through a first switch tube, and a third flying capacitor is A flying capacitor is connected to the voltage ground terminal through the second switch tube; the second flying capacitor is connected to the first flying capacitor through the third switch tube, and is connected to the first flying capacitor through the fourth switch tube, and the second flying capacitor is connected through the fifth switch tube. The switch tube is connected to the voltage ground terminal; the voltage output terminal is connected to the second flying capacitor through the sixth switch tube, and is connected to the second flying capacitor through the seventh switch tube, and the voltage output terminal is connected to the voltage ground terminal; A resonant inductor is also connected in series on the output current loop between the capacitor and the voltage output terminal. Under the same working conditions, fewer switching tubes, flying capacitors and resonant inductors are required, so it is beneficial to reduce the size of the converter, reduce losses, and improve power efficiency and power density.

Description

Three-state resonant switched capacitor power converter and control method thereof

technical field

The invention relates to the technical field of electric energy conversion, in particular to a three-state resonance switched capacitor power converter and a control method thereof.

Background technique

In the field of power conversion technology, DC-DC converters include inductive DC-DC converters, hybrid DC-DC converters and switched capacitor DC-DC converters. However, the traditional inductive DC-DC converter requires the switch to have a high withstand voltage capability, which brings reliability problems and increases the cost and power consumption of the converter; the hybrid type that uses switched capacitors to reduce the voltage drop at the switching node The DC-DC converter achieves small ripple through large inductance, but it will limit the power density; while the switched capacitor DC-DC converter composed of pure switched capacitors can solve the power density and withstand voltage problems, but has a large peak current , will lead to increased power consumption and withstand current.

Therefore, in order to meet the development trend of high-efficiency and high-power switching power supplies, resonant converters have become a research hotspot in the field of power conversion technology due to their soft-switching characteristics. However, most current resonant converters are based on isolated transformers, which generally limit the power density of the converter. Although there are some non-isolated resonant converters, most of these non-isolated resonant converters work in two-phase 4-state, while the resonant converters composed of two flying capacitors can only achieve 2:1 or 3:1 conversion Compare. For applications requiring a conversion ratio of 4:1, such as powering data centers, robots, drones, or handheld electronic devices, existing non-isolated converters require at least eight power transistors, at least two flying capacitors, and At least one resonant inductor, resulting in a limited power density of the converter.

SUMMARY OF THE INVENTION

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a three-state resonant switched capacitor power converter, which can reduce the number of switching tubes, thereby reducing the size of the converter, reducing losses, and improving power efficiency and power density.

The invention also provides a control method of the three-state resonance switched capacitor power converter.

In the first aspect, a tri-state resonant switched capacitor power converter according to an embodiment of the present invention includes a first flying capacitor, a first end of the first flying capacitor is connected with a first switch tube, and passes through the first switch tube Connected to the positive voltage terminal, the second terminal of the first flying capacitor is connected with a second switch tube, and is connected to the voltage ground terminal through the second switch tube; the second flying capacitor, the second terminal of the second flying capacitor One end is connected with a third switch tube and a fourth switch tube, and is connected with the first end of the first flying capacitor through the third switch tube, and is connected with the first flying capacitor through the fourth switch tube The second end of the second flying capacitor is connected to a fifth switch tube, and is connected to the voltage ground terminal through the fifth switch tube; the voltage output end is connected to the voltage output end. A sixth switch tube and a seventh switch tube are connected to the first end of the second flying capacitor through the sixth switch tube, and are connected to the second end of the second flying capacitor through the seventh switch tube A resonant inductor is also connected in series on the output current loop between the second flying capacitor and the voltage output end.

The tri-state resonant switched capacitor power converter according to the embodiment of the present invention has at least the following beneficial effects: the resonant circuit formed by the inductor and the capacitor can realize the use of energy exchange, the topology structure only needs seven switch tubes, the circuit topology is simple, and the Compared with existing resonant converters, less switching tubes, flying capacitors and resonant inductances are required under the same working conditions, so it is beneficial to reduce the size of the converter, reduce losses, and improve power efficiency and power density.

According to some embodiments of the present invention, the tri-state resonant switched capacitor power converter further includes an output capacitor, a first terminal of the output capacitor is connected to the voltage output terminal, and a second terminal of the output capacitor is connected to the voltage ground end connection.

According to some embodiments of the present invention, the first end of the resonant inductor is connected to the sixth switch tube and the seventh switch tube respectively, and is connected to the sixth switch tube of the second flying capacitor through the sixth switch tube One end is connected to the second end of the second flying capacitor through the seventh switch tube, and the second end of the resonant inductor is connected to the first end of the voltage output end.

According to some embodiments of the present invention, the first end of the resonant inductor is connected to the second end of the second flying capacitor, and the second end of the resonant inductor is connected to the fifth switch tube and the seventh switch, respectively. The switch tube is connected to the voltage ground terminal through the fifth switch tube, and is connected to the first end of the output capacitor through the seventh switch tube.

According to some embodiments of the present invention, the first switch transistor, the second switch transistor, the third switch transistor, the fourth switch transistor, the fifth switch transistor, the sixth switch transistor and The seventh switch tube adopts discrete or integrated power semiconductor devices.

According to some embodiments of the present invention, the first switch transistor, the second switch transistor, the third switch transistor, the fourth switch transistor, the fifth switch transistor, the sixth switch transistor and The seventh switch tube adopts MOSFET, IGBT or GaNFET.

According to some embodiments of the present invention, the three-state resonant switched capacitor power converter further includes an input power supply, the positive pole of the input power supply is the positive voltage terminal, and the negative pole of the input power supply is the voltage ground terminal.

According to some embodiments of the present invention, the input power source adopts a battery, a fuel cell or a photovoltaic cell.

According to some embodiments of the present invention, discrete or integrated capacitive elements are used for the first flying capacitor, the second flying capacitor and the output capacitor.

In a second aspect, according to a method for controlling a tri-state resonant switched capacitor power converter according to an embodiment of the present invention, based on the tri-state resonant switched capacitor power converter of the first aspect, the tri-state resonant switched capacitor power converter is configured with three working phase, including:

In the first phase, the first switching transistor, the fourth switching transistor and the seventh switching transistor are all turned on, the remaining switching transistors are all off, the first flying capacitor, the second flying capacitor and the the output capacitor is in a charged state;

In the second phase, the second switch transistor, the third switch transistor and the seventh switch transistor are all turned on, the remaining switch transistors are all off, the first flying capacitor is in a discharge state, the second both the flying capacitor and the output capacitor are in a charged state;

In the third phase, the second switch tube, the fifth switch tube and the sixth switch tube are all turned on, the rest of the switch tubes are turned off, the second flying capacitor is in a discharge state, and the output capacitor is charging.

The control method for a three-state resonant switched capacitor power converter according to an embodiment of the present invention has at least the following beneficial effects: using a resonant circuit formed by an inductor and a capacitor and turning on and off the first to seventh switch tubes at different phases The state can be used for energy exchange, and its topology requires only seven switches, and the circuit topology is simple. Therefore, it is beneficial to reduce the volume of the converter, reduce the loss, and improve the power efficiency and power density.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is one of the topological structure diagrams of the tri-state resonant switched capacitor power converter according to an embodiment of the present invention;

FIG. 2 is the second topological structure diagram of the three-state resonant switched capacitor power converter according to the embodiment of the present invention;

3a, 3b, and 3c are simplified circuit diagrams of the tri-state resonant switched capacitor power converter shown in FIG. 1 in the first phase, the second phase and the third phase, respectively;

4a, 4b, and 4c are simplified circuit diagrams of the tri-state resonant switched capacitor power converter shown in FIG. 2 in the first phase, the second phase and the third phase, respectively;

FIG. 5 is a partial waveform diagram of a three-state resonant switched capacitor power converter.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present invention, and should not be construed as a limitation of the present invention.

In the description of the present invention, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceeding, etc. are understood as not including this number, above, below, within, etc. are understood as including this number. If there is a description of "first", "second", etc., unless otherwise specified, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. The quantity or implicitly indicates the order of the indicated technical features.

In the description of the present invention, unless otherwise clearly defined, words such as connection and series connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

This embodiment discloses a three-state resonant switched capacitor power converter, which includes a first flying capacitor, a second flying capacitor and a voltage output terminal. The switch tube is connected to the positive voltage terminal, the second end of the first flying capacitor is connected to a second switch tube, and is connected to the voltage ground terminal through the second switch tube, and the first end of the second flying capacitor is connected to the third switch tube and The fourth switch tube is connected with the first end of the first flying capacitor through the third switch tube, and is connected with the second end of the first flying capacitor through the fourth switch tube, and the second end of the second flying capacitor is connected with the first Five switch tubes are connected to the voltage ground terminal through the fifth switch tube; the first end of the voltage output terminal is connected with the sixth switch tube and the seventh switch tube, and is connected to the first end of the second flying capacitor through the sixth switch tube , and the seventh switch tube is connected to the second end of the second flying capacitor, the second end of the voltage output end is connected to the voltage ground end, and the output current loop between the second flying capacitor and the voltage output end is also connected in series There are resonant inductors.

In this embodiment, the resonant circuit composed of inductors and capacitors can realize the use of energy exchange. The topology structure only needs seven switches, and the circuit topology is simple. Compared with the existing resonant converters, the required switches under the same working conditions There are fewer tubes, flying capacitors and resonant inductances, so it is beneficial to reduce the size of the converter, reduce losses, and improve power efficiency and power density. It should be noted that an output capacitor is connected to the voltage output end when in use, and it is worth understanding that the output capacitor can be built into the three-state resonant switched capacitor power converter or externally placed in the post-stage circuit. When the output capacitor is built in the three-state resonant switched capacitor power converter, the three-state resonant switched capacitor power converter further includes an output capacitor, the first terminal of the output capacitor is connected to the voltage output terminal, and the second terminal of the output capacitor is connected to the voltage ground terminal connect.

In order to further understand the topological structure of the three-state resonant switched capacitor power converter of the present embodiment, a detailed description is given below with reference to two topological examples in FIG. 1 and FIG. 2 .

Example 1

Please refer to FIG. 1 , the first flying capacitor, the second flying capacitor and the output capacitor correspond to the capacitor C1 , the capacitor C2 and the capacitor C _OUT respectively, the first to seventh switch tubes correspond to the switches S1 to S7 respectively, and the resonant inductor corresponds to the inductor _LR . In this embodiment, the first end of the resonant inductor is connected to the sixth switch tube and the seventh switch tube respectively, and is connected to the first end of the second flying capacitor through the sixth switch tube, and is connected to the sixth switch tube through the seventh switch tube. The second end of the two flying capacitors is connected, and the second end of the resonant inductor is connected to the first end of the output capacitor.

The three-state resonant switched capacitor power converter of this embodiment has three working phases during operation, and the corresponding switches are respectively controlled to be turned on or off under the three working phases. Different resonant circuits can be formed by using inductors and capacitors to Realize the use of energy exchange.

Please refer to FIG. 1 , FIG. 3 a , FIG. 3 b , FIG. 3 c and FIG. 5 , wherein FIG. 3 a , FIG. 3 b and FIG. 3 c show the first phase, the second phase and the third Phase-time simplified circuit, Figure 5 shows the waveform diagram of the three-state resonant switched capacitor power converter, where I _OUT is the current value flowing through the output capacitor, V _CF1 is the voltage value across the first flying capacitor, and V _CF2 is The voltage values across the second flying capacitor, φ ₁ , φ ₂ and φ ₃ respectively indicate that the converter is in the first phase, the second phase and the third phase.

Please refer to FIG. 3 a and FIG. 5 , in the first phase, the first switching transistor, the fourth switching transistor and the seventh switching transistor are all turned on, the remaining switching transistors are all off, the first flying capacitor, the second flying capacitor and the resonant inductor It is connected in series between the input voltage V _IN and the output voltage V _OUT , and the input voltage V _IN charges the first flying capacitor, the second flying capacitor and the output capacitor, that is, the first flying capacitor, the second flying capacitor and the output capacitor are all in charge state.

3b and 5, in the second phase, the second switch tube, the third switch tube and the seventh switch tube are turned on, the remaining switch tubes are all turned off, the second flying capacitor and the resonant inductor are connected in series at the first flying Between the capacitor and the output voltage V _OUT , the first flying capacitor is in a discharging state, and both the second flying capacitor and the output capacitor are in a charging state, so that the first flying capacitor charges the second flying capacitor and the output capacitor.

Please refer to FIG. 3c and FIG. 5 , in the third phase, the second switch tube, the fifth switch tube and the sixth switch tube are turned on, the remaining switch tubes are all turned off, and the second flying capacitor is connected in series between the resonant inductor and the output voltage V Between _OUT , the second terminal of the first flying capacitor is grounded, the first terminal of the first flying capacitor is open, the second flying capacitor is in a discharging state, and the output capacitor is in a charging state, so that the second flying capacitor can charge the output capacitor. .

Since the resonant inductor is always connected in series with the current output loop between the second flying capacitor and the output capacitor, the duration of the first phase, the second phase and the third phase can be controlled by adjusting the inductance value of the resonant inductor, so that the resonant current I _OUT , The waveforms of the voltage value V _CF1 and the voltage value V _CF2 are shown in FIG. 5 .

Example 2

Please refer to FIG. 2 , the first flying capacitor, the second flying capacitor and the output capacitor respectively correspond to the capacitor C1, the capacitor C2 and the capacitor C _OUT , the first to seventh switch tubes correspond to the switches S1 to S7 respectively, and the resonant inductor corresponds to the inductor _LR . The difference from Embodiment 1 is that in this embodiment, the first end of the resonant inductor is connected to the second end of the second flying capacitor, and the second end of the resonant inductor is connected to the fifth switch tube and the seventh switch tube respectively, and is The fifth switch tube is connected to the voltage ground terminal, and is connected to the first end of the output capacitor through the seventh switch tube.

Similar to Embodiment 1, the three-state resonant switched capacitor power converter of this embodiment also has three working phases during operation. same, i.e.:

Please refer to FIG. 1 , FIG. 4 a , FIG. 4 b , FIG. 4 c and FIG. 5 , wherein FIG. 4 a , FIG. 4 b and FIG. Phase-time simplified circuit, Figure 5 shows the waveform diagram of a three-state resonant switched capacitor power converter.

Referring to FIG. 4a and FIG. 5 , in the first phase, the first switch tube, the fourth switch tube and the seventh switch tube are all turned on, the remaining switch tubes are all turned off, the first flying capacitor, the second flying capacitor and the resonant inductor It is connected in series between the input voltage V _IN and the output voltage V _OUT , and the input voltage V _IN charges the first flying capacitor, the second flying capacitor and the output capacitor, that is, the first flying capacitor, the second flying capacitor and the output capacitor are all in charge state.

Referring to FIG. 4b and FIG. 5, in the second phase, the second switch tube, the third switch tube and the seventh switch tube are turned on, the remaining switch tubes are all turned off, and the second flying capacitor and the resonant inductor are connected in series at the first flying Between the capacitor and the output voltage V _OUT , the first flying capacitor is in a discharging state, and both the second flying capacitor and the output capacitor are in a charging state, so that the first flying capacitor charges the second flying capacitor and the output capacitor.

Please refer to FIG. 4c and FIG. 5 , in the third phase, the second switch tube, the fifth switch tube and the sixth switch tube are turned on, the rest of the switch tubes are turned off, and the second flying capacitor is connected in series between the resonant inductor and the output voltage V Between _OUT , the second terminal of the first flying capacitor is grounded, the first terminal of the first flying capacitor is open, the second flying capacitor is in a discharging state, and the output capacitor is in a charging state, so that the second flying capacitor can charge the output capacitor. .

Since the resonant inductor is always connected in series with the current output loop between the second flying capacitor and the output capacitor, the duration of the first phase, the second phase and the third phase can be controlled by adjusting the inductance value of the resonant inductor, so that the resonant current I _OUT , The waveforms of the voltage value V _CF1 and the voltage value V _CF2 are shown in FIG. 5 .

In the above embodiments, discrete or integrated power semiconductor devices are used for the first switch transistor, the second switch transistor, the third switch transistor, the fourth switch transistor, the fifth switch transistor, the sixth switch transistor and the seventh switch transistor. For example, the first switch transistor, the second switch transistor, the third switch transistor, the fourth switch transistor, the fifth switch transistor, the sixth switch transistor and the seventh switch transistor use MOSFET, IGBT or GaNFET. It should be understood that the first to seventh switches can use the same type of semiconductor devices, for example, only MOSFETs, or only IGBTs; the first to seventh switches can also use different types of semiconductor devices, for example, the first The switch tube adopts MOSFET, and the second switch tube adopts IGBT.

In practical applications, the positive voltage terminal and the voltage ground terminal in the tri-state resonant switched capacitor power converter can be provided by different power sources. For example, in some embodiments, the three-state resonant switched capacitor power converter further includes an input power supply, the positive pole of the input power supply is a positive voltage terminal, the negative pole of the input power supply is a voltage ground terminal, the input power supply adopts a battery, a fuel cell or a photovoltaic cell, and the input power supply is a battery, a fuel cell or a photovoltaic cell. The power supply can be compatible with battery power supply, which is conducive to the application of tri-state resonant switched capacitor power converters in scenarios such as power supply of data centers, robots, drones, and handheld electronic devices. For example, in some embodiments, the tri-state resonant switched capacitor power converter is powered by the voltage conversion circuit of the previous stage, and the positive voltage terminal and the voltage ground terminal are both interfaces adapted to the output terminal of the voltage conversion circuit.

The above embodiment shows the topology of the three-state resonant switched capacitor power converter, wherein the first flying capacitor, the second flying capacitor and the output capacitor use discrete capacitive elements, which is beneficial to reduce the number of capacitive elements. It should be understood that the first flying capacitor, the second flying capacitor, and the output capacitor may also adopt integrated capacitive elements, and the capacitive elements may be a single integrated capacitive element or a stack of multiple integrated capacitive elements.

The embodiment of the present invention also discloses a control method for a three-state resonant switched capacitor power converter. Based on the above-mentioned three-state resonant switched capacitor power converter, the three-state resonant switched capacitor power converter is configured with three working phases, including:

During the first phase, the first switch tube, the fourth switch tube and the seventh switch tube are all turned on, the remaining switch tubes are all turned off, and the first flying capacitor, the second flying capacitor and the output capacitor are in a charged state;

In the second phase, the second switch tube, the third switch tube and the seventh switch tube are all turned on, the remaining switch tubes are all turned off, the first flying capacitor is in a discharging state, and both the second flying capacitor and the output capacitor are in a charging state;

In the third phase, the second switch, the fifth switch and the sixth switch are all turned on, the rest of the switches are turned off, the second flying capacitor is in a discharging state, and the output capacitor is in a charging state.

The resonant circuit composed of inductors and capacitors and the on and off states of the first to seventh switches in different phases can realize energy exchange. The topology structure only needs seven switches, and the circuit topology is simple, which is different from the existing ones. Compared with the resonant converter with the same operating conditions, less switching tubes, flying capacitors and resonant inductance are required, so it is beneficial to reduce the size of the converter, reduce the loss, and improve the power efficiency and power density.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, and within the scope of knowledge possessed by those of ordinary skill in the art, various Variety.

Claims (10)

1. A three-state resonant switched capacitor power converter, comprising:

the first end of the first flying capacitor is connected with a first switching tube and is connected with a positive voltage end through the first switching tube, and the second end of the first flying capacitor is connected with a second switching tube and is connected with a voltage grounding end through the second switching tube;

the first end of the second flying capacitor is connected with a third switching tube and a fourth switching tube, and is connected with the first end of the first flying capacitor through the third switching tube and is connected with the second end of the first flying capacitor through the fourth switching tube, and the second end of the second flying capacitor is connected with a fifth switching tube and is connected with the voltage grounding end through the fifth switching tube;

the voltage output end is connected with a sixth switching tube and a seventh switching tube, connected with the first end of the second flying capacitor through the sixth switching tube and connected with the second end of the second flying capacitor through the seventh switching tube;

the output current loop between the second flying capacitor and the voltage output end is also connected with a resonant inductor in series;

when the first switch tube, the fourth switch tube and the seventh switch tube are all switched on, the rest switch tubes are all switched off;

when the second switching tube, the third switching tube and the seventh switching tube are all switched on, the rest switching tubes are all switched off;

when the second switch tube, the fifth switch tube and the sixth switch tube are all switched on, the rest switch tubes are all switched off.

2. The tri-state resonant switched capacitor power converter of claim 1 further comprising an output capacitor, a first terminal of the output capacitor being connected to the voltage output terminal and a second terminal of the output capacitor being connected to the voltage ground terminal.

3. The tri-state resonant switched-capacitor power converter as claimed in claim 2, wherein the first terminal of the resonant inductor is connected to the sixth switching transistor and the seventh switching transistor, respectively, and to the first terminal of the second flying capacitor through the sixth switching transistor, and to the second terminal of the second flying capacitor through the seventh switching transistor, and the second terminal of the resonant inductor is connected to the first terminal of the voltage output terminal.

4. The tri-state resonant switched capacitor power converter of claim 2, wherein a first terminal of the resonant inductor is connected to a second terminal of the second flying capacitor, and a second terminal of the resonant inductor is connected to the fifth switching transistor and the seventh switching transistor, respectively, and is connected to the voltage ground terminal through the fifth switching transistor, and is connected to the first terminal of the output capacitor through the seventh switching transistor.

5. The tri-state resonant switched capacitor power converter of claim 2, wherein the first switch transistor, the second switch transistor, the third switch transistor, the fourth switch transistor, the fifth switch transistor, the sixth switch transistor, and the seventh switch transistor are discrete or integrated power semiconductor devices.

6. The tri-state resonant switched capacitor power converter of claim 5, wherein the first, second, third, fourth, fifth, sixth and seventh switching transistors are MOSFETs, IGBTs or GaNFETs.

7. The tri-state resonant switched capacitor power converter of claim 2, further comprising an input power supply, wherein the positive pole of the input power supply is the positive voltage terminal and the negative pole of the input power supply is the voltage ground terminal.

8. The tri-state resonant switched capacitor power converter of claim 7, wherein the input power source is a battery, a fuel cell, or a photovoltaic cell.

9. The tri-state resonant switched capacitor power converter of claim 2, wherein the first flying capacitor, the second flying capacitor and the output capacitor employ discrete or integrated capacitive elements.

10. A method of controlling a three-state resonant switched-capacitor power converter, based on the three-state resonant switched-capacitor power converter of any of claims 2 to 8, wherein the three-state resonant switched-capacitor power converter is configured with three operating phases, comprising:

in a first phase, the first switch tube, the fourth switch tube and the seventh switch tube are all turned on, the rest switch tubes are all turned off, and the first flying capacitor, the second flying capacitor and the output capacitor are in a charging state;

in a second phase, the second switching tube, the third switching tube and the seventh switching tube are all switched on, the rest switching tubes are all switched off, the first flying capacitor is in a discharging state, and the second flying capacitor and the output capacitor are all in a charging state;

in a third phase, the second switching tube, the fifth switching tube and the sixth switching tube are all turned on, the rest switching tubes are all turned off, the second flying capacitor is in a discharging state, and the output capacitor is in a charging state.

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