Voltage equalization circuit

Abstract

The invention relates to a voltage balancing circuit which comprises a first capacitor, a second capacitor and a DCDC bidirectional converter. When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter works in a BUCK mode to balance the voltage between the first voltage line and the second voltage line; when the voltage value of the first voltage line is smaller than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter works in a BOOST mode to balance the voltage between the first voltage line and the second voltage line. According to the invention, voltage balance between different voltage lines can be realized without using a dummy load, so that the system efficiency can be effectively improved and the standby loss can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of charging modules, and more particularly to a voltage balancing circuit. Background Art

[0002] As the voltage resistance of switching tubes increases and the cost of switching tubes decreases, the auxiliary power source of three-phase input charging modules tends to use a single-winding auxiliary power source instead of the original dual-winding auxiliary power source and dual-tube flyback. However, a single-winding flyback often causes an imbalance in the positive and negative bus voltages, especially under light output load or no-load conditions. The conventional method to solve the imbalance in the positive and negative bus voltages is to add a dummy load, such as a pure resistor, to each of the positive and negative buses to improve and reduce the imbalance in the positive and negative bus voltages. However, the dummy load will cause standby loss and reduce system efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a voltage balancing circuit to address the above-mentioned defects of the prior art, which can achieve voltage balancing between different voltage lines without using a dummy load, thereby effectively improving system efficiency and reducing standby loss.

[0004] The technical solution adopted by the present invention to solve the technical problem is: constructing a voltage balancing circuit, including a first capacitor, a second capacitor and a DCDC bidirectional converter; The first capacitor is connected between a first voltage line and ground, the second capacitor is connected between a second voltage line and ground, a first end of the DCDC bidirectional converter is connected to the first voltage line, a second end is connected to the second voltage line, and a third end is grounded; When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a BUCK mode to balance the voltage between the first voltage line and the second voltage line; When the voltage value of the first voltage line is smaller than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a BOOST mode to balance the voltages between the first voltage line and the second voltage line.

[0005] In the voltage balancing circuit of the present invention, the DCDC bidirectional converter is composed of a first switching tube, a second switching tube and an inductor; The control ends of the first switching tube and the second switching tube respectively receive control signals; the first end of the first switching tube is connected to the first voltage line, and the second end is connected to the first end of the inductor and the first end of the second switching tube; the second end of the second switching tube is connected to the second voltage line; and the second end of the inductor is grounded.

[0006] In the voltage balancing circuit of the present invention, the DCDC bidirectional converter includes a first switching tube, a second switching tube and an inductor; The control ends of the first switching tube and the second switching tube respectively receive control signals; the first end of the first switching tube is connected to the first voltage line, and the second end is connected to the first end of the inductor and the first end of the second switching tube; the second end of the second switching tube is connected to the second voltage line; and the second end of the inductor is grounded.

[0007] In the voltage balancing circuit of the present invention, when the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a buck mode to balance the voltage between the first voltage line and the second voltage line, including: When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is turned on and the second switch tube is turned off to control the inductor to store energy, or the first switch tube is turned off and the second switch tube is turned on or off to control the inductor to release energy.

[0008] In the voltage balancing circuit of the present invention, in different modes, the first switch tube is turned on and the second switch tube is turned off to control the inductor to store energy, or the first switch tube is turned off and the second switch tube is turned on or off to control the inductor to release energy, including: In a first mode, the first switch is turned on and the second switch is turned off. At this time, the current in the voltage balancing circuit flows from the first voltage line through the first switch, the inductor, the ground, and the first capacitor in sequence and returns to the first voltage line. Therefore, the inductor stores energy. In the second mode, the first switch tube is turned off and the second switch tube is turned on. At this time, the current direction in the voltage balancing circuit is from the inductor through the ground, the second capacitor, the second voltage line, and the second switch tube in sequence and returns to the inductor. At this time, the inductor releases energy.

[0009] In the voltage balancing circuit of the present invention, in different modes, the first switch tube is turned on and the second switch tube is turned off to control the inductor to store energy, or the first switch tube is turned off and the second switch tube is turned on or off to control the inductor to release energy, including: In a first mode, the first switch is turned on and the second switch is turned off. At this time, the current in the voltage balancing circuit flows from the first voltage line through the first switch, the inductor, the ground, and the first capacitor in sequence and returns to the first voltage line. Therefore, the inductor stores energy. In the second mode, the first switch tube is turned off and the second switch tube is turned off. At this time, the current direction in the voltage balancing circuit is from the inductor through the ground, the second capacitor, the second voltage line, and the freewheeling diode of the second switch tube in sequence and returns to the inductor. At this time, the inductor releases energy.

[0010] In the voltage balancing circuit of the present invention, when the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a BOOST mode to balance the voltage between the first voltage line and the second voltage line, including: When the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is disconnected and the second switch tube is turned on to control the inductor to store energy, or the first switch tube is turned on or off and the second switch tube is disconnected to control the inductor to release energy.

[0011] In the voltage balancing circuit of the present invention, when the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is turned off and the second switch tube is turned on to control the inductor to store energy, or the first switch tube is turned on or off and the second switch tube is turned off to control the inductor to release energy, including: In a first mode, the first switch is off and the second switch is on. At this time, the current in the voltage balancing circuit flows from the ground through the inductor, the second switch, the second voltage line, and the second capacitor in sequence and returns to the ground, so that the inductor stores energy. In the second mode, the first switch tube is turned on and the second switch tube is turned off. At this time, the current direction in the voltage balancing circuit is from the inductor through the first switch tube, the first voltage line, the first capacitor and the ground in sequence and returns to the inductor. At this time, the inductor releases energy.

[0012] In the voltage balancing circuit of the present invention, when the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is turned off and the second switch tube is turned on to control the inductor to store energy, or the first switch tube is turned on or off and the second switch tube is turned off to control the inductor to release energy, including: In a first mode, the first switch is off and the second switch is on. At this time, the current in the voltage balancing circuit flows from the ground through the inductor, the second switch, the second voltage line, and the second capacitor in sequence and returns to the ground, so that the inductor stores energy. In the second mode, the first switch tube is turned off and the second switch tube is turned off. At this time, the current direction in the voltage balancing circuit is from the inductor through the freewheeling diode of the first switch tube, the first voltage line, the first capacitor and the ground in sequence and returns to the inductor. At this time, the inductor releases energy.

[0013] In the voltage balancing circuit of the present invention, the first voltage line is a positive busbar, and the second voltage line is a negative busbar; or the first voltage line is a positive output line of a battery, and the second voltage line is a negative output line of a battery.

[0014] A voltage balancing circuit according to the present invention includes a first capacitor, a second capacitor, and a DC-DC bidirectional converter disposed between a first voltage line, a second voltage line, and ground. When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, the DC-DC bidirectional converter operates in a BUCK mode. When the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, the DC-DC bidirectional converter operates in a BOOST mode. Therefore, voltage balancing between different voltage lines can be achieved without using a dummy load, thereby effectively improving system efficiency and reducing standby loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 is a principle block diagram of a preferred embodiment of the voltage balancing circuit of the present invention; Figure 2 A circuit diagram of another preferred embodiment of the voltage balancing circuit of the present invention; Figure 3 yes Figure 2 The current diagram of the voltage balancing circuit in BUCK mode is shown; Figure 4 yes Figure 2 The current diagram of the voltage balancing circuit in BOOST mode is shown; Figure 5 yes Figure 2 The control waveform diagram of the two switching tubes of the voltage balancing circuit shown in the figure under the synchronous rectification mode; Figure 6 yes Figure 2 The control waveform diagram of the two switching tubes of the voltage balancing circuit shown in the figure is in asynchronous rectification mode. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Figure 1 FIG. 1 is a block diagram of a preferred embodiment of the voltage balancing circuit of the present invention. Figure 1 As shown, the voltage balancing circuit of the present invention includes: a capacitor C1, a capacitor C2, and a DC-DC bidirectional converter 100. The capacitor C1 is connected between a voltage line V1 and ground AGND, and the capacitor C2 is connected between a voltage line V2 and ground AGND. The DC-DC bidirectional converter 100 has a first terminal connected to the voltage line V1, a second terminal connected to the voltage line V2, and a third terminal connected to ground AGND. When the voltage value of the voltage line V1 is greater than the absolute value of the voltage value of the voltage line V2, the DC-DC bidirectional converter 100 operates in a BUCK mode to balance the voltages between the voltage lines V1 and V2. When the voltage value of the voltage line V1 is less than the absolute value of the voltage value of the voltage line V2, the DC-DC bidirectional converter 100 operates in a BOOST mode to balance the voltages between the voltage lines V1 and V2.

[0018] The DC-DC bidirectional converter 100 does not contain any resistor components. Preferably, the DC-DC bidirectional converter 100 includes a switch Q1, a switch Q2, and an inductor L7. More preferably, the DC-DC bidirectional converter 100 comprises a switch Q1, a switch Q2, and an inductor L7. Of course, in other preferred embodiments of the present invention, other designs may be employed to construct the DC-DC bidirectional converter 100.

[0019] In a preferred embodiment of the present invention, the voltage line V1 is a positive busbar, and the voltage line V2 is a negative busbar. In this case, the voltage balancing circuit is a positive and negative busbar voltage balancing circuit, which is applicable to a three-phase input charging module.

[0020] In another preferred embodiment of the present invention, the voltage line V1 is the battery output positive line, and the voltage line V2 is the battery output negative line. In this case, the voltage balancing circuit is an output battery voltage balancing circuit, which can be used for series voltage balancing of output battery voltages.

[0021] In other preferred embodiments of the present invention, the voltage balancing circuit of the present invention may also be applied to any other suitable scenarios to balance the voltage between the first voltage line and the second voltage line.

[0022] A voltage balancing circuit according to the present invention includes a first capacitor, a second capacitor, and a DC-DC bidirectional converter disposed between a first voltage line, a second voltage line, and ground. When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, the DC-DC bidirectional converter operates in a BUCK mode. When the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, the DC-DC bidirectional converter operates in a BOOST mode. Therefore, voltage balancing between different voltage lines can be achieved without using a dummy load, thereby effectively improving system efficiency and reducing standby loss.

[0023] Figure 2 A circuit diagram of another preferred embodiment of the voltage balancing circuit of the present invention. Figure 2 The voltage balancing circuit shown is a positive and negative bus voltage balancing circuit, which is applicable to a three-phase input charging module. Figure 2 As shown, the voltage balancing circuit of the present invention includes: a capacitor C1, a capacitor C2 and a DCDC bidirectional converter 100; the capacitor C1 is connected between the positive bus +VBUS and the ground AGND, the capacitor C2 is connected between the negative bus -VBUS and the ground AGND, the first end of the DCDC bidirectional converter 100 is connected to the positive bus +VBUS, the second end is connected to the negative bus -VBUS, and the third end is connected to the ground AGND. Figure 2 As shown, the DC-DC bidirectional converter 100 comprises a switch Q1, a switch Q2, and an inductor L7. The control terminals of the switches Q1 and Q2 receive control signals, respectively. The first terminal of the switch Q1 is connected to the positive bus +VBUS and the first terminal of the capacitor C1, while the second terminal is connected to the first terminal of the inductor L7 and the first terminal of the switch Q2. The second terminal of the switch Q2 is connected to the negative bus -VBUS. The second terminal of the inductor L7 is grounded AGND. The first terminal of the capacitor C1 is grounded, and the second terminal is connected to the negative bus -VBUS.

[0024] When the voltage of the positive bus +VBUS is greater than the absolute value of the voltage of the negative bus -VBUS, in different modes, the switch Q1 is turned on and the switch Q2 is turned off, thereby controlling the inductor L7 to store energy, or the switch Q1 is turned off and the switch Q2 is turned on or off, thereby controlling the inductor L7 to release energy. When the voltage of the positive bus +VBUS is less than the absolute value of the voltage of the negative bus -VBUS, in different modes, the switch Q1 is turned off and the switch Q2 is turned on, thereby controlling the inductor L7 to store energy, or the switch Q1 is turned on or off and the switch Q2 is turned off, thereby controlling the inductor L7 to release energy.

[0025] Figure 2In the preferred embodiment shown, the switching transistors Q1 and Q2 are MOS transistors, with their control terminals being gates, their first terminals being sources, and their second terminals being drains. Those skilled in the art will appreciate that the switching transistors Q1 and Q2 may alternatively be triodes, IGBTs, or the like, all of which fall within the scope of protection of the present invention.

[0026] In this preferred embodiment, the DC-DC bidirectional converter 100, consisting solely of the switch tubes Q1, Q2, and inductor L7, can complete the transfer of the capacitive charge between capacitors C1 and C2, thereby regulating the voltages of the positive bus +VBUS and the negative bus -VBUS. In other preferred embodiments of the present invention, diodes and other devices may also be further provided in the circuit. However, it should be noted that the DC-DC bidirectional converter 100, consisting solely of the switch tubes Q1, Q2, and inductor L7, can achieve voltage balancing between the positive bus +VBUS and the negative bus -VBUS.

[0027] Figure 3 yes Figure 2 The current diagram of the voltage balancing circuit in BUCK mode is shown. Figure 4 yes Figure 2 The current diagram of the voltage balancing circuit in BOOST mode is shown. Figure 5 yes Figure 2 The control waveform diagram of the two switching tubes of the voltage balancing circuit shown in the figure under the synchronous rectification mode; Figure 6 yes Figure 2 The control waveforms of the two switching tubes of the voltage balancing circuit shown in the figure are in the asynchronous rectification mode. Figures 2 to 6 The principle of the voltage balancing circuit of the present invention is described as follows.

[0028] When the voltage value of the positive bus +VBUS is greater than the absolute value of the voltage value of the negative bus -VBUS, the DCDC bidirectional converter 100 operates in BUCK mode to balance the voltage between the positive bus +VBUS and the negative bus -VBUS. At this time, the voltage is transferred from the positive bus +VBUS to the negative bus -VBUS for balance. If the switch tube Q1 and the switch tube Q2 operate in synchronous rectification mode, their control waveforms are as follows: Figure 5 As shown, the switch tube Q1 serves as the master switch tube, and the switch tube Q2 serves as the slave switch tube.

[0029] In the first mode, the switch tube Q1 is turned on and the switch tube Q2 is turned off. At this time, the current direction in the voltage balancing circuit ( Figure 3 The current 1) in FIG1 is a current flowing from the positive bus +VBUS through the switch Q1, the inductor L7, the ground AGND, and the capacitor C1 in sequence and returns to the positive bus +VBUS. Therefore, the inductor L7 stores energy.

[0030] In the second mode, the switch tube Q1 is turned off and the switch tube Q2 is turned on. At this time, the current direction in the voltage balancing circuit ( Figure 3 The current 2) in the flow is from the inductor L7 through the ground AGND, the capacitor C2, the negative bus -VBUS, and the switch Q2 in sequence and returns to the inductor L7. At this time, the inductor L7 releases energy.

[0031] It should be noted that when the voltage value of the positive bus +VBUS is greater than the absolute value of the voltage value of the negative bus -VBUS, the DCDC bidirectional converter 100 operates in the BUCK mode. At this time, the switch tube Q1 and the switch tube Q2 can also operate in the asynchronous rectification mode, and the control waveform is as follows: Figure 6 As shown, the switch tube Q1 is used as the master switch tube, and the switch tube Q2 is used as the slave switch tube. At this time, the switch tube Q2 can be always turned off, and only the internal diode of the switch tube Q2 is used for freewheeling. The principle is as follows.

[0032] In the first mode, the switch tube Q1 is turned on and the switch tube Q2 is turned off. At this time, the current direction in the voltage balancing circuit ( Figure 3 The current 1) in the figure flows from the positive bus +VBUS through the switch Q1, the inductor L7, the ground AGND, and the capacitor C1 in sequence and returns to the positive bus +VBUS. Therefore, the inductor L7 stores energy. In the second mode, the switch tube Q1 is turned off and the switch tube Q2 is turned off. At this time, the current direction in the voltage balancing circuit is from the inductor L7 through the ground AGND, the capacitor C2, the negative bus -VBUS and the freewheeling diode of the switch tube Q2 in sequence and returns to the inductor L7. At this time, the inductor L7 releases energy.

[0033] When the voltage value of the positive bus +VBUS is less than the absolute value of the voltage value of the negative bus -VBUS, the DCDC bidirectional converter operates in BOOST mode to balance the voltage between the positive bus +VBUS and the negative bus -VBUS; at this time, the voltage is transferred from the negative bus -VBUS to the positive bus +VBUS for balance. If the switch tube Q1 and the switch tube Q2 operate in synchronous rectification mode, their control waveforms are as follows: Figure 5 As shown, the switch tube Q1 serves as the master switch tube, and the switch tube Q2 serves as the slave switch tube.

[0034] In the first mode, the switch tube Q1 is turned off and the switch tube Q2 is turned on. At this time, the current direction in the voltage balancing circuit ( Figure 4The current 2) in the circuit flows from the ground AGND through the inductor L7, the switch Q2, the negative bus -VBUS, and the capacitor C2 in sequence and returns to the ground AGND, so the inductor L7 stores energy. In the second mode, the switch tube Q1 is turned on and the switch tube Q2 is turned off. At this time, the current direction in the voltage balancing circuit ( Figure 4 The current 1) in FIG. 1 is a current flowing from the inductor L7 through the switch Q1, the positive bus +VBUS, the capacitor C1, and the ground AGND in sequence and returns to the inductor L7. At this time, the inductor L7 releases energy.

[0035] It should be noted that when the voltage value of the positive bus +VBUS is less than the absolute value of the voltage value of the negative bus -VBUS, the DCDC bidirectional converter operates in BOOST mode. At this time, the switch tube Q1 and the switch tube Q2 can also operate in asynchronous rectification mode, and the control waveform is as follows: Figure 6 As shown, the switch tube Q2 acts as the master switch tube, and the switch tube Q1 acts as the slave switch tube. At this time, the switch tube Q1 can be always off, and only the internal diode of the switch tube Q1 is used for freewheeling, and the principle is as follows.

[0036] In the first mode, the switch tube Q1 is turned off and the switch tube Q2 is turned on. At this time, the current direction in the voltage balancing circuit is from the ground AGND through the inductor L7, the switch tube Q2, the negative bus -VBUS and the capacitor C2 in sequence and returns to the ground AGND, so the inductor L7 stores energy.

[0037] In the second mode, the switch tube Q1 is turned off and the switch tube Q2 is turned off. At this time, the current direction in the voltage balancing circuit ( Figure 4 The current 1) in the figure flows from the inductor L7 through the freewheeling diode of the switch tube Q1, the positive bus +VBUS, the capacitor C1, and the ground AGND in sequence and returns to the inductor L7. At this time, the inductor L7 releases energy.

[0038] By implementing the voltage balancing circuit of the present invention, the DC-DC bidirectional converter 100 composed of the switch tubes Q1 and Q2 and the inductor L7 can complete the transfer of the capacitive charges of the capacitors C1 and C2, thereby adjusting the voltage of the positive bus +VBUS and the negative bus -VBUS, and achieving voltage conversion between the positive bus +VBUS and the negative bus -VBUS. Since this conversion efficiency can reach over 98%, it can be used to adjust applications with large VBUS voltage differences and large capacitor values, thereby improving system efficiency and system no-load standby loss.

[0039] Although the present invention is described by way of specific embodiments, it will be understood by those skilled in the art that various modifications and equivalent substitutions may be made to the present invention without departing from the scope of the present invention. Furthermore, various modifications may be made to the present invention for specific circumstances or materials without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but is intended to encompass all embodiments falling within the scope of the claims.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A voltage balancing circuit, characterized in that: include: A first capacitor, a second capacitor and a DCDC bidirectional converter; The first capacitor is connected between a first voltage line and ground, the second capacitor is connected between a second voltage line and ground, a first end of the DCDC bidirectional converter is connected to the first voltage line, a second end is connected to the second voltage line, and a third end is grounded; When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a BUCK mode to balance the voltage between the first voltage line and the second voltage line; When the voltage value of the first voltage line is smaller than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a BOOST mode to balance the voltages between the first voltage line and the second voltage line.

2. The voltage balancing circuit according to claim 1, wherein: The DCDC bidirectional converter is composed of a first switching tube, a second switching tube and an inductor; The control ends of the first switching tube and the second switching tube respectively receive control signals; the first end of the first switching tube is connected to the first voltage line, and the second end is connected to the first end of the inductor and the first end of the second switching tube; the second end of the second switching tube is connected to the second voltage line; and the second end of the inductor is grounded.

3. The voltage balancing circuit according to claim 1, wherein: The DCDC bidirectional converter comprises a first switching tube, a second switching tube and an inductor; The control ends of the first switching tube and the second switching tube respectively receive control signals; the first end of the first switching tube is connected to the first voltage line, and the second end is connected to the first end of the inductor and the first end of the second switching tube; the second end of the second switching tube is connected to the second voltage line; and the second end of the inductor is grounded.

4. The voltage equalization circuit according to claim 2 or 3, characterized in that: When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a BUCK mode to balance the voltage between the first voltage line and the second voltage line, including: When the voltage value of the first voltage line is greater than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is turned on and the second switch tube is turned off to control the inductor to store energy, or the first switch tube is turned off and the second switch tube is turned on or off to control the inductor to release energy.

5. The voltage balancing circuit according to claim 4, wherein: In different modes, the first switch tube is turned on and the second switch tube is turned off to control the inductor to store energy, or the first switch tube is turned off and the second switch tube is turned on or off to control the inductor to release energy, including: In a first mode, the first switch is turned on and the second switch is turned off. At this time, the current in the voltage balancing circuit flows from the first voltage line through the first switch, the inductor, the ground, and the first capacitor in sequence and returns to the first voltage line. Therefore, the inductor stores energy. In the second mode, the first switch tube is turned off and the second switch tube is turned on. At this time, the current direction in the voltage balancing circuit is from the inductor through the ground, the second capacitor, the second voltage line, and the second switch tube in sequence and returns to the inductor. At this time, the inductor releases energy.

6. The voltage balancing circuit according to claim 5, wherein: In different modes, the first switch tube is turned on and the second switch tube is turned off to control the inductor to store energy, or the first switch tube is turned off and the second switch tube is turned on or off to control the inductor to release energy, including: In a first mode, the first switch is turned on and the second switch is turned off. At this time, the current in the voltage balancing circuit flows from the first voltage line through the first switch, the inductor, the ground, and the first capacitor in sequence and returns to the first voltage line. Therefore, the inductor stores energy. In the second mode, the first switch tube is turned off and the second switch tube is turned off. At this time, the current direction in the voltage balancing circuit is from the inductor through the ground, the second capacitor, the second voltage line, and the freewheeling diode of the second switch tube in sequence and returns to the inductor. At this time, the inductor releases energy.

7. The voltage equalization circuit according to claim 2 or 3, characterized in that: When the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, the DCDC bidirectional converter operates in a BOOST mode to equalize the voltage between the first voltage line and the second voltage line, including: When the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is disconnected and the second switch tube is turned on to control the inductor to store energy, or the first switch tube is turned on or off and the second switch tube is disconnected to control the inductor to release energy.

8. The voltage balancing circuit according to claim 7, wherein: When the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is turned off and the second switch tube is turned on to control the inductor to store energy, or the first switch tube is turned on or off and the second switch tube is turned off to control the inductor to release energy, including: In a first mode, the first switch is off and the second switch is on. At this time, the current in the voltage balancing circuit flows from the ground through the inductor, the second switch, the second voltage line, and the second capacitor in sequence and returns to the ground, so that the inductor stores energy. In the second mode, the first switch tube is turned on and the second switch tube is turned off. At this time, the current direction in the voltage balancing circuit is from the inductor through the first switch tube, the first voltage line, the first capacitor and the ground in sequence and returns to the inductor. At this time, the inductor releases energy.

9. The voltage balancing circuit according to claim 8, wherein: When the voltage value of the first voltage line is less than the absolute value of the voltage value of the second voltage line, in different modes, the first switch tube is turned off and the second switch tube is turned on to control the inductor to store energy, or the first switch tube is turned on or off and the second switch tube is turned off to control the inductor to release energy, including: In a first mode, the first switch is off and the second switch is on. At this time, the current in the voltage balancing circuit flows from the ground through the inductor, the second switch, the second voltage line, and the second capacitor in sequence and returns to the ground, so that the inductor stores energy. In the second mode, the first switch tube is turned off and the second switch tube is turned off. At this time, the current direction in the voltage balancing circuit is from the inductor through the freewheeling diode of the first switch tube, the first voltage line, the first capacitor and the ground in sequence and returns to the inductor. At this time, the inductor releases energy.

10. The voltage balancing circuit according to any one of claims 1 to 9, wherein: The first voltage line is a positive busbar, and the second voltage line is a negative busbar; or The first voltage line is a positive output line of the battery, and the second voltage line is a negative output line of the battery.

Images