Flying capacitor three-level boost circuit

Abstract

The utility model discloses a flying capacitor three-level boost circuit, which comprises a three-level boost module, an energy storage capacitor C1, an input capacitor Cin and a fifth one-way diversion piece, the three-level boosting module comprises an energy storage inductor L1, a first switch tube Q1 of a semiconductor, a second switch tube Q2 of the semiconductor, a first bus capacitor Cbus +, a second bus capacitor Cbus-, a first one-way diversion piece, a second one-way diversion piece, a third one-way diversion piece, a fourth one-way diversion piece and a flying capacitor Cfly. The head end of the energy storage inductor L1 is connected with the head end of the energy storage capacitor C1, the head end of the input capacitor Cin and the cut-off end of the fifth one-way diversion part, the tail end of the energy storage capacitor C1 is connected with the tail end of the energy storage inductor L1, the conduction end of the fifth one-way diversion part is used for being connected with the positive electrode of a power supply, and the tail end of the input capacitor Cin is used for being connected with the negative electrode of the power supply. The boost efficiency is improved, the element cost is reduced, the operation is stable and reliable, and the risk of damage to the input power supply is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of power equipment, especially to a flying capacitor three-level boost circuit. BACKGROUND

[0002] The flying capacitor three-level boost circuit is a common boost conversion circuit in the field of power electronics, which can make the output voltage higher than the input voltage, and is commonly used in the DC side part of a photovoltaic inverter. For the same output voltage level, the voltage stress of the power switching device in the flying capacitor three-level boost circuit is low when it is normally working, so a low-voltage power switching device can be used to achieve high-voltage and high-power output.

[0003] However, in actual use, the output voltage of the flying capacitor three-level boost circuit still cannot meet the needs of some loads, at which time the specifications of the power switching device, energy storage inductor, energy storage capacitor and other components need to be improved, which means a substantial increase in cost. In addition, the ripple generated by the flying capacitor three-level boost circuit during operation may impact the input power supply and cause damage to it. SUMMARY

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a flying capacitor three-level boost circuit, which improves the boost efficiency, reduces the component cost, is stable and reliable in operation, and reduces the risk of damage to the input power supply.

[0005] According to the first aspect embodiment of the utility model discloses a kind of flying capacitor three-level boost circuits, comprising: three-level boost module, including energy storage inductor L1, semiconductor's first switch tube Q1, semiconductor's second switch tube Q2, first bus capacitor Cbus+, second bus capacitor Cbus-, first one-way flow guide, second one-way flow guide, third one-way flow guide, fourth one-way flow guide and flying capacitor Cfly, the input end of the first switch tube Q1 is connected with the tail end of energy storage inductor L1 and the conducting end of the first one-way flow guide respectively, the cutoff end of the first one-way flow guide is connected with the head end of the flying capacitor Cfly, the conducting end of the second one-way flow guide and the cutoff end of the fourth one-way flow guide respectively, the output end of the first switch tube Q1 is connected with the input end of the second switch tube Q2, the tail end of the flying capacitor Cfly and the conducting end of the third one-way flow guide respectively, the cutoff end of the second one-way flow guide is connected with the head end of the first bus capacitor Cbus+, the tail end of the first bus capacitor Cbus+ is connected with the cutoff end of the third one-way flow guide, the conducting end of the fourth one-way flow guide and the head end of second bus capacitor Cbus- respectively, the output end of the second switch tube Q2 is connected with the tail end of second bus capacitor Cbus- and the negative pole of power supply respectively;Energy storage capacitor C1, input capacitor Cin and fifth one-way flow guide, the head end of energy storage inductor L1 is connected with the head end of the energy storage capacitor C1, the head end of the input capacitor Cin and the cutoff end of the fifth one-way flow guide respectively, the tail end of the energy storage capacitor C1 is connected with the tail end of energy storage inductor L1, the conducting end of the fifth one-way flow guide is used to be connected with the positive pole of power supply, the tail end of the input capacitor Cin is used to be connected with the negative pole of power supply;Wherein, in the first one-way flow guide, the second one-way flow guide, the third one-way flow guide, the fourth one-way flow guide and fifth one-way flow guide are all allowed to flow from conducting end to cutoff end and limit current from cutoff end to conducting end.

[0006] According to the utility model embodiment, a kind of flying capacitor three-level boost circuits at least has following beneficial effects:

[0007] The utility model discloses flying capacitor three-level boost circuit, input capacitor Cin filters the input voltage of power supply, so that output is more stable, power supply is energy storage capacitor C1, when the first switch tube Q1 and the second switch tube Q2 are off, energy storage capacitor C1 discharges to provide energy for output voltage, slow down the attenuation of output voltage, and fifth one-way flow guide can prevent voltage and current ripple to be transmitted to power supply, reduce the risk of power supply damage, compared with traditional flying capacitor three-level boost circuit, the design improves boost efficiency, reduces component cost, stable and reliable operation, reduce the risk of damage to input power supply.

[0008] According to some embodiments of the present application, the flying capacitor three-level boost circuit further comprises a control module, the control module is connected with the controlled end of the first switch tube Q1 and the controlled end of the second switch tube Q2 respectively.

[0009] According to some embodiments of the present application, the control module controls the first switch tube Q1 and the second switch tube Q2 to run to switch between at least the first on-off state, the second on-off state and the third on-off state, in the first on-off state, the first switch tube Q1 is turned on, and the second switch tube Q2 is turned off; in the second on-off state, the first switch tube Q1 is turned off, and the second switch tube Q2 is turned on; in the third on-off state, the first switch tube Q1 is turned off, and the second switch tube Q2 is turned off.

[0010] According to some embodiments of the present application, the flying capacitor three-level boost circuit further comprises a voltage equalizing component, the voltage equalizing component comprises a first voltage equalizing end, a second voltage equalizing end and a third voltage equalizing end, the first voltage equalizing end is connected with the cutoff end of the second unidirectional flow guide and the first bus capacitor Cbus+ first end respectively, the second voltage equalizing end is connected with the cutoff end of the first unidirectional flow guide, the first end of the flying capacitor Cfly, the conducting end of the second unidirectional flow guide and the cutoff end of the fourth unidirectional flow guide respectively, and the third voltage equalizing end is connected with the conducting end of the first unidirectional flow guide, the input end of the first switch tube Q1 and the tail end of the energy storage inductor L1 respectively, wherein the voltage division voltage between the first voltage equalizing end and the second voltage equalizing end is equal to the voltage division voltage between the second voltage equalizing end and the third voltage equalizing end.

[0011] According to some embodiments of the present application, the voltage equalizing component comprises resistors R1 and R2 with the same resistance, the first end of the resistor R1 forms the third voltage equalizing end, the tail end of the resistor R1 is connected with the first end of the resistor R2 to form the second voltage equalizing end, and the tail end of the resistor R2 forms the first voltage equalizing end.

[0012] According to some embodiments of the present application, the voltage equalizing component comprises two voltage stabilizing tubes.

[0013] According to some embodiments of the present application, the first unidirectional flow guide, the second unidirectional flow guide, the third unidirectional flow guide, the fourth unidirectional flow guide and the fifth unidirectional flow guide are all diodes, the conducting end is the positive electrode of the diode, and the cutoff end is the negative electrode of the diode.

[0014] According to some embodiments of the present application, the first unidirectional flow guide, the second unidirectional flow guide, the third unidirectional flow guide, the fourth unidirectional flow guide and the fifth unidirectional flow guide are all thyristors.

[0015] According to some embodiments of the present application, the first switch tube Q1 is an IGBT transistor, a triode or a MOS tube.

[0016] According to some embodiments of the present application, the second switch tube Q2 is an IGBT transistor, a triode or a MOS tube.

[0017] The additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter in the description of the application. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description of embodiments, given by way of example, and with reference to the following drawings, wherein:

[0019] Figure 1 It is a circuit schematic diagram of one embodiment of the flying capacitor three-level boost circuit of the present application.

[0020] REFERENCE NUMERALS

[0021] Control module 100; first one-way flow guide 210; second one-way flow guide 220; third one-way flow guide 230; fourth one-way flow guide 240; fifth one-way flow guide 250; voltage equalizing assembly 300. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0023] In the description of the present application, it should be understood that, in relation to the orientation description, for example, the orientation or position relationship indicated by the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation of the present application.

[0024] In the description of the utility model, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceed and the like are understood as not including the number, above, below, within and the like are understood as including the number.If there is a description to the first, the second is only used for distinguishing the technical features for the purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0025] In the description of the utility model, it needs to be explained that, unless there is explicit provision and limitation, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, can also be detachable connection, or integrally connected;It can be mechanical connection, or electrical connection;It can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication between two elements internally.For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0026] For example, Figure 1As shown, according to the first aspect embodiment of the utility model discloses a fly capacitor three -level boost circuit, including three -level boost module, energy storage capacitor C1, input capacitor Cin and fifth one -way flow guide piece 250, three -level boost module includes energy storage inductance L1, semiconductor's first switch tube Q1, semiconductor's second switch tube Q2, first bus capacitor Cbus+, second bus capacitor Cbus-, first one -way flow guide piece 210, second one -way flow guide piece 220, third one -way flow guide piece 230, fourth one -way flow guide piece 240 and fly capacitor Cfly, the input end of first switch tube Q1 is connected with the tail end of energy storage inductance L1 and the conducting end of first one -way flow guide piece 210 respectively, the cutoff end of first one -way flow guide piece 210 is connected with the first end of fly capacitor Cfly, the conducting end of second one -way flow guide piece 220 and the cutoff end of fourth one -way flow guide piece 240 respectively, the output end of first switch tube Q1 is connected with the input end of second switch tube Q2, the tail end of fly capacitor Cfly and the conducting end of third one -way flow guide piece 230 respectively, the cutoff end of second one -way flow guide piece 220 is connected with the first end of first bus capacitor Cbus+, the tail end of first bus capacitor Cbus+ is connected with the cutoff end of third one -way flow guide piece 230, the conducting end of fourth one -way flow guide piece 240 and the first end of second bus capacitor Cbus- respectively, the output end of second switch tube Q2 is connected with the tail end of second bus capacitor Cbus- and the negative pole of power supply respectively, the first end of energy storage inductance L1 is connected with the first end of energy storage capacitor C1, the first end of input capacitor Cin and the cutoff end of fifth one -way flow guide piece 250 respectively, the tail end of energy storage capacitor C1 is connected with the tail end of energy storage inductance L1, the conducting end of fifth one -way flow guide piece 250 is used to be connected with the positive pole of power supply, the tail end of input capacitor Cin is used to be connected with the negative pole of power supply, wherein, in first one -way flow guide piece 210, second one -way flow guide piece 220, third one -way flow guide piece 230, fourth one -way flow guide piece 240 and fifth one -way flow guide piece 250, current is allowed to flow from conducting end to cutoff end and current is limited to flow from cutoff end to conducting end.

[0027] Wherein, in some embodiments of the utility model, fly capacitor three -level boost circuit still includes control module 100, control module 100 is connected with the controlled end of first switch tube Q1 and the controlled end of second switch tube Q2 respectively.

[0028] The control module 100 can comprise a processor such as an MCU or a CPU and its associated circuit, and further comprises a PWM signal generating chip; the processor generates a first PWM signal and a second PWM signal in cooperation with the PWM signal generating chip; the first PWM signal is output to the controlled end of the first switch tube Q1, and the second PWM signal is output to the controlled end of the second switch tube Q2; the first PWM signal and the second PWM signal are 180 degrees out of phase; and the processor realizes the voltage sharing control of Vbus+, Vbus- and the output voltage by adjusting the duty cycle of the first PWM signal and the second PWM signal.

[0029] In some embodiments of the utility model, the first one-way flow guide 210, the second one-way flow guide 220, the third one-way flow guide 230, the fourth one-way flow guide 240 and the fifth one-way flow guide 250 are all diodes, the conducting end is the positive pole of the diode, and the cutoff end is the negative pole of the diode.

[0030] Current can flow from the positive pole of the diode to the negative pole of the diode, but cannot flow from the negative pole of the diode to the positive pole of the diode.

[0031] Alternatively, the first one-way flow guide 210, the second one-way flow guide 220, the third one-way flow guide 230, the fourth one-way flow guide 240 and the fifth one-way flow guide 250 are all thyristors, and a synchronization circuit is used to control the first one-way flow guide 210, the second one-way flow guide 220, the third one-way flow guide 230, the fourth one-way flow guide 240 and the fifth one-way flow guide 250 to conduct at the same time.

[0032] In some embodiments of the utility model, the first switch tube Q1 is an IGBT transistor, a triode or a MOS tube, and in some embodiments of the utility model, the second switch tube Q2 is an IGBT transistor, a triode or a MOS tube.

[0033] The utility model cross capacitor three level boost circuit, input capacitor Cin filters the input voltage of power supply, makes the output more stable, and the power supply charges the energy storage capacitor C1, when the first switch tube Q1 and the second switch tube Q2 are off, the energy storage capacitor C1 discharges and provides energy for the output voltage, slows down the attenuation of the output voltage, and the fifth one-way flow guide 250 can prevent voltage and current ripple from being transmitted to the power supply, reduce the risk of damaging the power supply, compared with the traditional cross capacitor three level boost circuit, the design improves the boost efficiency, reduces the component cost, and is stable and reliable in operation, reduces the risk of damaging the input power supply.

[0034] In some embodiments of the utility model, the control module 100 controls the first switch tube Q1 and the second switch tube Q2 to run to switch between at least the first on-off state, the second on-off state and the third on-off state, in the first on-off state, the first switch tube Q1 is turned on, and the second switch tube Q2 is turned off, in the second on-off state, the first switch tube Q1 is turned off, and the second switch tube Q2 is turned on, in the third on-off state, the first switch tube Q1 is turned off, and the second switch tube Q2 is turned off.

[0035] When the flying capacitor three-level boost circuit starts, the voltage of the first one-way flow guide 210 and the second one-way flow guide 220 is unbalanced, which may cause damage to the first one-way flow guide 210 and the second one-way flow guide 220, in some embodiments of the utility model, the flying capacitor three-level boost circuit further includes a voltage equalizing component 300, the voltage equalizing component 300 includes a first voltage equalizing end, a second voltage equalizing end and a third voltage equalizing end, the first voltage equalizing end is connected with the cutoff end of the second one-way flow guide 220 and the first bus capacitor Cbus+ first end respectively, the second voltage equalizing end is connected with the cutoff end of the first one-way flow guide 210, the first end of the flying capacitor Cfly, the conduction end of the second one-way flow guide 220 and the cutoff end of the fourth one-way flow guide 240 respectively, and the third voltage equalizing end is connected with the conduction end of the first one-way flow guide 210, the input end of the first switch tube Q1 and the tail end of the energy storage inductor L1 respectively, wherein the voltage division voltage between the first voltage equalizing end and the second voltage equalizing end is equal to the voltage division voltage between the second voltage equalizing end and the third voltage equalizing end.

[0036] The voltage division voltage between the first voltage equalizing end and the second voltage equalizing end is equal to the voltage division voltage between the second voltage equalizing end and the third voltage equalizing end, which can clamp the voltage of the first one-way flow guide 210 and the second one-way flow guide 220, and reduce the probability of damage to the first one-way flow guide 210 and the second one-way flow guide 220.

[0037] Specifically, the voltage equalizing component 300 includes resistors R1 and R2 with the same resistance, the first end of the resistor R1 forms the third voltage equalizing end, the tail end of the resistor R1 is connected with the first end of the resistor R2 to form the second voltage equalizing end, and the tail end of the resistor R2 forms the first voltage equalizing end.

[0038] Alternatively, the voltage equalizing component 300 includes two voltage stabilizing tubes, which can clamp the voltage to a set value.

[0039] Any technical features in the above-described embodiments can be combined, and for the sake of brevity, not all possible combinations are described, however, any combination of the technical features is considered to be within the scope of the present specification.

[0040] Although the embodiments of the present application have been shown and described, it should be understood by those ordinary skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A flying-capacitor three-level boost converter, characterized by, The application relates to a three-level boost module. The three-level boost module comprises an energy storage inductor L1, a first semiconductor switch Q1, a second semiconductor switch Q2, a first bus capacitor Cbus+, a second bus capacitor Cbus-, a first unidirectional current guide, a second unidirectional current guide, a third unidirectional current guide, a fourth unidirectional current guide and a flying capacitor Cfly, the input end of the first semiconductor switch Q1 is connected with the tail end of the energy storage inductor L1 and the conducting end of the first unidirectional current guide, the cutoff end of the first unidirectional current guide is connected with the head end of the flying capacitor Cfly, the conducting end of the second unidirectional current guide and the cutoff end of the fourth unidirectional current guide, the output end of the first semiconductor switch Q1 is connected with the input end of the second semiconductor switch Q2, the tail end of the flying capacitor Cfly and the conducting end of the third unidirectional current guide, the cutoff end of the second unidirectional current guide is connected with the head end of the first bus capacitor Cbus+, the tail end of the first bus capacitor Cbus+ is connected with the cutoff end of the third unidirectional current guide, the conducting end of the fourth unidirectional current guide and the head end of the second bus capacitor Cbus-, and the output end of the second semiconductor switch Q2 is connected with the tail end of the second bus capacitor Cbus- and the negative electrode of a power supply; The three-level boost module further comprises an energy storage capacitor C1, an input capacitor Cin and a fifth unidirectional current guide, the head end of the energy storage inductor L1 is connected with the head end of the energy storage capacitor C1, the head end of the input capacitor Cin and the cutoff end of the fifth unidirectional current guide, the tail end of the energy storage capacitor C1 is connected with the tail end of the energy storage inductor L1, the conducting end of the fifth unidirectional current guide is connected with the positive electrode of a power supply, and the tail end of the input capacitor Cin is connected with the negative electrode of a power supply. In the first unidirectional current guide, the second unidirectional current guide, the third unidirectional current guide, the fourth unidirectional current guide and the fifth unidirectional current guide, current is allowed to flow from the conducting end to the cutoff end and current is limited to flow from the cutoff end to the conducting end.

2. The flying-capacitor three-level boost circuit according to claim 1, wherein The three-level boost module further comprises a control module connected with the controlled end of the first semiconductor switch Q1 and the controlled end of the second semiconductor switch Q2.

3. The flying-capacitor three-level boost circuit according to claim 2, wherein The control module controls the first semiconductor switch Q1 and the second semiconductor switch Q2 to switch between at least a first on-off state, a second on-off state and a third on-off state, in the first on-off state, the first semiconductor switch Q1 is on and the second semiconductor switch Q2 is off, in the second on-off state, the first semiconductor switch Q1 is off and the second semiconductor switch Q2 is on, and in the third on-off state, the first semiconductor switch Q1 is off and the second semiconductor switch Q2 is off.

4. The flying capacitor three-level boost circuit according to claim 1, wherein The voltage equalizing assembly comprises a first voltage equalizing end, a second voltage equalizing end and a third voltage equalizing end, the first voltage equalizing end is connected with the cutoff end of the second one-way flow guide and the first bus capacitor Cbus+ respectively, the second voltage equalizing end is connected with the cutoff end of the first one-way flow guide, the first end of the flying capacitor Cfly, the conducting end of the second one-way flow guide and the cutoff end of the fourth one-way flow guide respectively, and the third voltage equalizing end is connected with the conducting end of the first one-way flow guide, the input end of the first switch Q1 and the tail end of the energy storage inductor L1 respectively, wherein the voltage between the first voltage equalizing end and the second voltage equalizing end is equal to the voltage between the second voltage equalizing end and the third voltage equalizing end.

5. The flying-capacitor three-level boost circuit according to claim 4, wherein The voltage equalizing assembly comprises resistors R1 and R2 with the same resistance, the first end of the resistor R1 forms the third voltage equalizing end, the tail end of the resistor R1 is connected with the first end of the resistor R2 to form the second voltage equalizing end, and the tail end of the resistor R2 forms the first voltage equalizing end.

6. The flying-capacitor three-level boost circuit according to claim 4, wherein The voltage equalizing assembly comprises two voltage stabilizing tubes.

7. The flying-capacitor three-level boost circuit according to claim 1, wherein The first one-way flow guide, the second one-way flow guide, the third one-way flow guide, the fourth one-way flow guide and the fifth one-way flow guide are diodes, the conducting end is the positive electrode of the diode, and the cutoff end is the negative electrode of the diode.

8. The flying capacitor three-level boost circuit according to claim 1, wherein The first one-way flow guide, the second one-way flow guide, the third one-way flow guide, the fourth one-way flow guide and the fifth one-way flow guide are thyristors.

9. The flying capacitor three-level boost circuit according to claim 1, wherein The first switch Q1 is an IGBT transistor, a triode or a MOS tube.

10. The flying capacitor three-level boost circuit according to claim 1, wherein The second switch Q2 is an IGBT transistor, a triode or a MOS tube.

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