Multi-level battery active equalization circuit

Abstract

The invention discloses a multi-level battery active equalization circuit which is provided with a controller, a switch control unit and an energy transfer unit, the controller is connected with the switch control unit, and the energy transfer unit is connected with a first to-be-equalized target, a second to-be-equalized target and the switch control unit; the controller is used for collecting first voltage information of a first to-be-balanced target and second voltage information of a second to-be-balanced target and then controlling the working state of the switch control unit to transmit electric energy of the first to-be-balanced target to the second to-be-balanced target through the energy transfer unit. Or the electric energy of the second to-be-balanced target is transmitted to the first to-be-balanced target through the energy transfer unit, so that the preset states of the first to-be-balanced target and the second to-be-balanced target are the same, and the preset state balance between the first to-be-balanced target and the second to-be-balanced target is realized; the technical problems of high energy consumption, high cost and poor applicability during equalization between battery modules or between battery PACKs in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery balancing, and in particular to a multi-level battery active balancing circuit. Background Art

[0002] Battery balancing is an important means of safe battery use and maintaining battery life. In related technologies, when the power supply system is a multi-level battery system, the battery balancing methods include 1. resistor discharge balancing; 2. DCDC power supply charge (discharge) balancing. There are corresponding technical defects in the above two balancing methods. The first balancing method converts electric heat into heat energy and dissipates it, which has poor energy-saving effect; the second balancing method requires the introduction of an external power supply, and requires the power of the external power supply to adapt to the current battery system, resulting in poor standardization and applicability of the battery system.

[0003] Therefore, how to solve the technical problems of high energy consumption, high cost and poor applicability in battery balancing in the related art has become a technical problem that those skilled in the art need to solve. Summary of the invention

[0004] The present invention provides a multi-level active battery balancing circuit to solve the technical problems of high energy consumption, high cost and poor applicability of battery balancing in the related art.

[0005] A multi-level active battery balancing circuit in the present invention comprises:

[0006] a controller, configured to collect first voltage information of a first target to be balanced and second voltage information of a second target to be balanced; the first target to be balanced and the second target to be balanced are battery modules in the same battery PACK, or the first target to be balanced and the second target to be balanced are battery PACKs respectively;

[0007] A switch control unit, connected to the controller, whose working state is controlled by a control signal sent by the controller;

[0008] An energy transfer unit is connected to the first target to be balanced, the second target to be balanced, and the switch control unit respectively; and is used to receive the electric energy of the first target to be balanced and transfer it to the second target to be balanced, or receive the electric energy of the second target to be balanced and transfer it to the first target to be balanced, so that the preset states of the first target to be balanced and the second target to be balanced are the same.

[0009] A multi-level active battery balancing circuit according to an embodiment of the present invention has at least the following beneficial effects:

[0010] According to an embodiment of the present invention, a multi-level active battery balancing circuit is provided with a controller, a switch control unit and an energy transfer unit, wherein the controller is connected to the switch control unit, and the energy transfer unit is connected to a first target to be balanced, a second target to be balanced and the switch control unit respectively; wherein the controller is used to collect first voltage information of the first target to be balanced and second voltage information of the second target to be balanced, and then control the working state of the switch control unit to transmit the electric energy of the first target to be balanced to the second target to be balanced through the energy transfer unit, or to transmit the electric energy of the second target to be balanced to the first target to be balanced through the energy transfer unit, so that the preset states of the first target to be balanced and the second target to be balanced are the same, and the preset state balancing between the first target to be balanced and the second target to be balanced is achieved, and the technical problems of high energy consumption, high cost and poor applicability in the related art when balancing between battery modules or between battery PACKs are solved; the multi-level active battery balancing circuit provided by the embodiment of the present invention not only realizes low energy consumption balancing by energy transmission, but also realizes balancing between battery modules or between battery PACKs by directly introducing the control of the switch control unit by the controller, thereby improving the balancing efficiency. At the same time, the embodiment of the present invention reduces the battery balancing cost and improves the applicability of the circuit without introducing an external charging power supply.

[0011] According to some other embodiments of the multi-level battery active balancing circuit of the present invention, the energy transfer unit includes a current monitoring unit and an energy storage unit;

[0012] The first end of the current monitoring unit is respectively connected to the negative electrode of the first target to be balanced, the positive electrode of the second target to be balanced, and the first current monitoring interface of the controller, the second end of the current monitoring unit is respectively connected to the first end of the energy storage unit and the second current monitoring interface of the controller, and the second end of the energy storage unit is connected to the switch control unit.

[0013] According to some other embodiments of the multi-level battery active balancing circuit of the present invention, the current monitoring unit includes a first resistor; and the energy storage unit includes a first inductor.

[0014] According to some other embodiments of the multi-level battery active balancing circuit of the present invention, the switch control unit includes a first switch circuit and a second switch circuit;

[0015] The first end of the first switch circuit is connected to the positive electrode of the first target to be balanced, the second end of the first switch circuit is respectively connected to the first end of the second switch unit and the energy transfer unit, the second end of the second switch circuit is connected to the negative electrode of the second target to be balanced, and the control end of the first switch circuit and the control end of the second switch circuit are respectively connected to the controller.

[0016] According to some other embodiments of the multi-level battery active balancing circuit of the present invention, the first switch circuit includes a first switch tube and a second switch tube; the second switch circuit includes a third switch tube and a fourth switch tube;

[0017] The first end of the first switch tube is connected to the positive electrode of the first target to be balanced, the second end of the first switch tube is connected to the second end of the second switch tube, the first end of the second switch tube is connected to the connection point between the first end of the third switch tube and the energy storage unit, the second end of the third switch tube is connected to the second end of the fourth switch tube, and the first end of the fourth switch tube is connected to the negative electrode of the second target to be balanced; the control end of the first switch tube, the control end of the second switch tube, the control end of the third switch tube, and the control end of the fourth switch tube are respectively connected to the controller.

[0018] The multi-level battery active balancing circuit according to other embodiments of the present invention further includes a first overcurrent protection unit, a second overcurrent protection unit and a third overcurrent protection unit;

[0019] The first overcurrent protection unit is arranged between the first target to be balanced and the switch control unit;

[0020] A first end of the second overcurrent protection unit is connected to the energy transfer unit, and a second end of the second overcurrent protection circuit is connected to a connection point between the negative electrode of the first target to be balanced and the positive electrode of the second target to be balanced;

[0021] The third overcurrent protection unit is arranged between the second target to be balanced and the switch control unit.

[0022] The multi-level active battery balancing circuit according to other embodiments of the present invention further includes a first filtering and voltage stabilizing unit and a second filtering and voltage stabilizing unit;

[0023] A first end of the first filtering and stabilizing unit is connected to a connection point between the first overcurrent protection unit and the switch control unit, and a second end of the first filtering and stabilizing unit is connected to a connection point between the second overcurrent protection unit and the energy transfer unit;

[0024] The first end of the second filtering and stabilizing unit is connected to the connection point between the second overcurrent protection unit and the energy transfer unit, and the second end of the second filtering and stabilizing unit is connected to the connection point between the third overcurrent protection unit and the switch control unit.

[0025] According to the multi-level battery active balancing circuit of other embodiments of the present invention, the controller outputs a PWM control signal to control the working state of the switch control circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the module composition of a first embodiment of a multi-level battery active equalization circuit of the present invention;

[0027] Figure 2 This is a schematic diagram of the module composition of a second embodiment of a multi-level battery active equalization circuit of the present invention;

[0028] Figure 3 It is a schematic diagram of the module composition of a third embodiment of a multi-level battery active equalization circuit of the present invention;

[0029] Figure 4 It is a schematic diagram of the module composition of a fourth embodiment of a multi-level battery active balancing circuit of the present invention;

[0030] Figure 5 It is a schematic diagram of the module composition of a fifth embodiment of a multi-level battery active equalization circuit of the present invention;

[0031] Figure 6 It is a schematic diagram of the circuit composition structure of a specific embodiment of a multi-level battery active balancing circuit of the present invention;

[0032] Figure 7 The present invention is a schematic diagram of a multi-level battery active equalization circuit according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the concept of the invention and the technical effects produced in combination with the embodiments, so as to fully understand the purpose, characteristics and effects of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of them. Based on the embodiments of the invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the invention.

[0034] In the description of the embodiments of the present invention, if "several" is involved, it means more than one, if "multiple" is involved, it means more than two, if "greater than", "less than" or "exceed" is involved, it should be understood as not including the number itself, if "above", "below" or "within" is involved, it should be understood as including the number itself. If "first" or "second" is involved, it should be understood as being used to distinguish technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] Reference Figure 1, an embodiment of the present invention provides a multi-level battery active balancing circuit, which includes a controller, a switch control unit and an energy transfer unit; wherein the first target to be balanced and the second target to be balanced are two adjacent battery modules in the same battery PACK, or the first target to be balanced and the second target to be balanced are adjacent battery PACKs. In this embodiment, the controller is connected to the first target to be balanced, the second target to be balanced, and the switch control unit respectively, the energy transfer unit is connected to the first target to be balanced, the second target to be balanced, and the switch control unit respectively, and the switch control unit is connected to the first target to be balanced and the second target to be balanced respectively. In this embodiment, the controller is used to collect the first voltage information of the first target to be balanced and the second voltage information of the second target to be balanced, and determine the direction of energy transfer, that is, the balancing process is to transfer the electric energy of the first target to be balanced to the second target to be balanced, or to transfer the electric energy of the second target to be balanced to the first target to be balanced; after determining the direction of energy transfer, the controller controls the on-off of the switch control unit to realize the transmission of the electric energy of the first target to be balanced to the second target to be balanced through the energy transfer unit so that the preset states of the two are the same, thereby realizing the balancing process, or controls the on-off of the switch control unit to realize the transmission of the electric energy of the second target to be balanced to the first target to be balanced through the energy transfer unit so that the preset states of the two are the same, thereby realizing the balancing process. The multi-level active balancing circuit provided in the embodiment of the present invention avoids the high energy consumption of converting electric energy into heat energy in the related art by balancing through energy transfer, and realizes the balancing of the battery system without introducing an external power supply, thereby reducing the battery balancing cost and improving the applicability of the battery system.

[0036] In some embodiments, when equalization is completed, the first target to be equalized and the second target to be equalized have the same preset state, which includes any one or more of the following preset values ​​being the same: the same voltage value, the same SOC, the same SOE, etc.

[0037] Reference Figure 2In some embodiments, during the battery balancing process, it is necessary to monitor the charge / discharge current of the batteries at each level at all times to prevent the charge / discharge current from being too large and causing accidents that may cause safety accidents. To achieve current monitoring during the balancing process, the energy transfer unit includes a current monitoring unit and an energy storage unit; wherein the first end of the current monitoring unit is respectively connected to the negative pole of the first target to be balanced, the positive pole of the second target to be balanced, and the first current monitoring interface of the controller, and the second end of the current monitoring unit is respectively connected to the first end of the energy storage unit and the second current monitoring interface of the controller, and the second end of the energy storage unit is connected to the switch control unit. In this embodiment, a current monitoring unit is provided to monitor the charge / discharge current of the first target to be balanced and the second target to be balanced in real time during the balancing process through the controller, and then after monitoring that the charge / discharge current exceeds the preset value, the controller controls the working state of the switch control unit, stops the balancing process, and can be connected to an external device to realize an alarm prompt when the current exceeds the preset value, thereby ensuring the safety of the balancing process.

[0038] Reference Figure 3 In some embodiments, in order to accurately control the switch control unit to balance the first target to be balanced and the second target to be balanced, in this embodiment, the switch control unit includes a first switch circuit and a second switch circuit. Specifically, the first end of the first switch circuit is connected to the positive electrode of the first target to be balanced, the second end of the first switch circuit is respectively connected to the first end of the second switch circuit and the energy transfer unit, the second end of the second switch circuit is connected to the negative electrode of the second target to be balanced, and the control end of the first switch circuit and the control end of the second switch circuit are respectively connected to the controller. After the first switch circuit, the energy transfer unit, and the first target to be balanced form a loop, the first target to be balanced outputs energy to the energy transfer unit for storage, or the energy stored in the energy transfer unit charges the first target to be balanced. The second switch circuit, the energy transfer unit, and the second target to be balanced form a loop, and the energy stored in the energy transfer unit charges the second target to be balanced, or the second target to be balanced outputs energy to the energy transfer unit for storage.

[0039] Reference Figure 4In some embodiments, in order to prevent the instantaneous current from being too large during the balancing process and thus burning the components in the circuit, in this embodiment, a first overcurrent protection unit, a second overcurrent protection unit and a third overcurrent protection unit are provided; wherein the first overcurrent protection unit is provided between the first target to be balanced and the switch control unit, and is used to protect the first target to be balanced from being too large in the line current between the first target to be balanced and the switch control unit when charging or discharging, thereby burning the first target to be balanced or the components in the switch control unit; the first end of the second overcurrent protection unit is connected to the energy transfer unit, and the second end of the second overcurrent protection unit is connected to the connection point of the negative electrode of the first target to be balanced and the positive electrode of the second target to be balanced, and is used to prevent the line current between the energy transfer unit and the first target to be balanced, the second target to be balanced or the components in the energy transfer unit from being too large, thereby burning the first target to be balanced, the second target to be balanced or the components in the energy transfer unit; the third overcurrent protection unit is provided between the second target to be balanced and the switch control unit, and is used to prevent the line current between the second target to be balanced and the switch control unit from being too large, thereby burning the second target to be balanced or the components in the switch control unit.

[0040] Reference Figure 5 In some embodiments, in order to ensure the voltage stability of the first target to be balanced and the second target to be balanced during charging and discharging during the balancing period, a first filtering and voltage stabilizing unit and a second filtering and voltage stabilizing unit are further provided; specifically, the first end of the first filtering and voltage stabilizing unit is connected to the connection point between the first overcurrent protection unit and the switch control unit, and the second end of the first filtering and voltage stabilizing unit is connected to the connection point between the second overcurrent protection unit and the energy transfer unit, that is, the two ends of the first filtering and voltage stabilizing unit are respectively arranged at the positive and negative poles of the first target to be balanced, and then the first target to be balanced is charged / discharged after filtering and voltage stabilizing by the first filtering and voltage stabilizing unit during charging / discharging, which plays a protective role on the circuit; the first end of the second filtering and voltage stabilizing unit is connected to the connection point between the second overcurrent protection unit and the energy transfer unit, and the second end of the second filtering and voltage stabilizing unit is connected to the connection point between the third overcurrent protection unit and the switch control unit, that is, the two ends of the second filtering and voltage stabilizing unit are respectively arranged at the positive and negative poles of the second target to be balanced, and then the second target to be balanced is charged / discharged after filtering and voltage stabilizing by the second filtering and voltage stabilizing unit during charging / discharging, which plays a protective role on the circuit.

[0041] Reference Figure 6 The following is a specific implementation method of the multi-level active equalization circuit provided by the embodiment of the present invention. It should be noted that this embodiment is only a specific embodiment. No creative improvement is made on this embodiment. Only various simple changes are made and still fall within the protection scope of the multi-level active equalization circuit proposed in the embodiment of the present invention.

[0042] In this embodiment, U1 and U2 represent the first target to be balanced and the second target to be balanced, respectively, which may be adjacent battery modules or adjacent battery PACKs in the same battery PACK. The first switch circuit includes a first switch tube and a second switch tube, and the second switch circuit includes a third switch tube and a fourth switch tube. In this embodiment, each switch tube is implemented by a MOS tube, but it is obvious that each MOS tube can be replaced by other switch tubes with equivalent functions, such as IGBT, GaN, etc. Specifically, the first switch circuit includes a first MOS tube Q1 and a second MOS tube Q2, and the second switch circuit includes a third MOS tube Q3 and a fourth MOS tube Q4. The current monitoring unit includes a first resistor R, and the energy storage unit includes a first inductor L. The first overcurrent protection unit, the second overcurrent protection unit, and the third overcurrent protection unit correspond to fuses F1, F2, and F3, respectively. The first filter and voltage stabilization unit includes a first capacitor C1, and the second filter and voltage stabilization unit includes a second capacitor C2. In this embodiment, the controller is connected to the first target to be balanced U1 and the second target to be balanced U2, respectively, for collecting voltage information of the two. If the voltage value information of the two is inconsistent, electric energy balancing is required. In this implementation, energy transfer from the first target to be balanced to the second target to be balanced is used as an example for explanation. Specifically, in order to realize battery balancing by controlling the switch control unit, in this embodiment, the source of the first MOS tube Q1 (i.e., the second end of the first switch tube) is connected to the source of the second MOS tube Q2 (i.e., the second end of the second switch tube), and the drain of the first MOS tube (i.e., the first end of the first MOS tube) is connected to the positive electrode of the first target to be balanced U1. In order to protect the circuit, a first fuse F1 is provided on the connection line connecting the drain of the first MOS tube to the positive electrode of the first target to be balanced U1, and a first capacitor C1 is connected in parallel at both ends of the positive and negative electrodes of the first target to be balanced U1 for filtering and voltage stabilization. The drain of the second MOS tube Q2 (i.e., the first end of the second switch tube) is respectively connected to one end of the first inductor L and the drain of the third MOS tube Q3 (i.e., the first end of the third switch tube). The first end of the first inductor L is connected to one end of the first resistor R, and the other end of the first resistor R is connected to the connection point of the first target to be balanced U1 and the second target to be balanced U2. In order to protect the circuit, a second fuse F2 is arranged between the first resistor R and the first target to be balanced U1 and the second target to be balanced U2, and a second capacitor C2 is connected in parallel at both ends of the positive and negative electrodes of the second target to be balanced U2 for filtering and voltage stabilization. The source of the third MOS tube Q3 (that is, the second end of the third switch tube) is connected to the source of the fourth MOS tube Q4 (that is, the second end of the fourth switch tube), the drain of the fourth MOS tube Q4 (that is, the first end of the fourth switch tube) is connected to the negative electrode of the second target to be balanced U2, and a third fuse F3 is arranged on the connection line between the drain of the fourth MOS tube Q4 and the negative electrode of the second target to be balanced U2, for overcurrent protection of the circuit.The controller is respectively connected to the gate (control end) of the first MOS tube Q1, the gate (control end) of the second MOS tube Q2, the gate (control end) of the third MOS tube Q3, and the gate (control end) of the fourth MOS tube Q4. The controller controls the on-off state of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3, and the fourth MOS tube Q4 by outputting a PWM control signal. Normally, each MOS tube is in an off state. When the controller detects that the first target to be balanced U1 needs to transmit electric energy to the second target to be balanced U2 to achieve the balancing process, the controller outputs a PWM control signal to turn on the first MOS tube Q1 and the second MOS tube Q2. , at this time, the first target to be balanced U1 and the loop of the first inductor L are connected, and the electric energy on the first target to be balanced U1 is transmitted to the first inductor L, and then the first MOS tube Q1 and the second MOS tube Q2 are controlled to be disconnected, and the third MOS tube Q3 and the fourth MOS tube Q4 are turned on. At this time, the second target to be balanced U2 and the loop of the first inductor L are connected, and the electric energy on the first inductor L continues to flow to the second target to be balanced, and then by continuously controlling the on-off state of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3, and the fourth MOS tube Q4, the voltage value, SOC or SOE of the first target to be balanced U1 and the second target to be balanced U2 are finally achieved to be consistent, and the balancing process is completed. Among them, the two ends of the first resistor R are respectively connected to the current monitoring first interface and the current monitoring second interface of the controller, which are used to monitor the current size in real time during the balancing process. When the current is too large, the balancing process can be stopped by the controller, and an alarm prompt can be issued by communicating with the external device. In this embodiment, in order to ensure stable and safe operation of each device during the balancing process, the voltage withstand level of the first MOS transistor Q1, the second MOS transistor Q2, the third MOS transistor Q3, and the fourth MOS transistor Q4 is designed to be twice that of the first target to be balanced U1 or the second target to be balanced U2.

[0043] Reference Figure 7, the following is an example of a specific application of the multi-level battery active balancing circuit proposed in the embodiment of the present invention through a specific embodiment. In this embodiment, the multi-level battery active balancing circuit is applied to a battery system including multiple battery PACKs and battery modules, wherein each battery PACK includes multiple battery modules, and each battery module includes multiple battery cells. Furthermore, the multi-level battery active balancing circuit is connected to two adjacent battery modules and the multi-level battery active balancing circuit is connected to two adjacent battery PACKs. Furthermore, when performing battery balancing between adjacent battery modules or battery PACKs, active balancing is achieved by the multi-level battery active balancing circuit proposed in the embodiment of the present invention, and the balancing process between battery modules or battery PACKs is achieved without consuming a lot of energy, introducing an external power supply, or introducing devices with different isolation levels due to the high or low system operating voltage, thereby solving the technical problems of high energy consumption, high cost, complex electrical isolation, and poor applicability in the related art when performing balancing between battery modules or battery PACKs.

[0044] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A multi-level active battery balancing circuit, characterized in that: include: A controller, configured to collect first voltage information of a first target to be balanced and second voltage information of a second target to be balanced; The first target to be balanced and the second target to be balanced are battery modules in the same battery PACK, or the first target to be balanced and the second target to be balanced are battery PACKs respectively; A switch control unit, connected to the controller, whose working state is controlled by a control signal sent by the controller; an energy transfer unit, connected to the first target to be balanced, the second target to be balanced, and the switch control unit respectively; The device is used for receiving the electric energy of the first target to be balanced and transferring it to the second target to be balanced, or receiving the electric energy of the second target to be balanced and transferring it to the first target to be balanced, so that the preset states of the first target to be balanced and the second target to be balanced are the same.

2. The multi-level battery active balancing circuit according to claim 1, characterized in that: The energy transfer unit includes a current monitoring unit and an energy storage unit; The first end of the current monitoring unit is respectively connected to the negative electrode of the first target to be balanced, the positive electrode of the second target to be balanced, and the first current monitoring interface of the controller, the second end of the current monitoring unit is respectively connected to the first end of the energy storage unit and the second current monitoring interface of the controller, and the second end of the energy storage unit is connected to the switch control unit.

3. The multi-level active battery balancing circuit according to claim 2, characterized in that: The current monitoring unit includes a first resistor; and the energy storage unit includes a first inductor.

4. The multi-level active equalization circuit according to claim 2 or 3, characterized in that: The switch control unit includes a first switch circuit and a second switch circuit; The first end of the first switch circuit is connected to the positive electrode of the first target to be balanced, the second end of the first switch circuit is respectively connected to the first end of the second switch circuit and the energy transfer unit, the second end of the second switch circuit is connected to the negative electrode of the second target to be balanced, and the control end of the first switch circuit and the control end of the second switch circuit are respectively connected to the controller.

5. The multi-level active equalization circuit according to claim 4, characterized in that: The first switch circuit includes a first switch tube and a second switch tube; the second switch circuit includes a third switch tube and a fourth switch tube; The first end of the first switch tube is connected to the positive electrode of the first target to be balanced, the second end of the first switch tube is connected to the second end of the second switch tube, the first end of the second switch tube is connected to the connection point between the first end of the third switch tube and the energy storage unit, the second end of the third switch tube is connected to the second end of the fourth switch tube, and the first end of the fourth switch tube is connected to the negative electrode of the second target to be balanced; the control end of the first switch tube, the control end of the second switch tube, the control end of the third switch tube, and the control end of the fourth switch tube are respectively connected to the controller.

6. The multi-level active equalization circuit according to any one of claims 1 to 3, characterized in that: Also includes a first overcurrent protection unit, a second overcurrent protection unit and a third overcurrent protection unit; The first overcurrent protection unit is arranged between the first target to be balanced and the switch control unit; A first end of the second overcurrent protection unit is connected to the energy transfer unit, and a second end of the second overcurrent protection circuit is connected to a connection point between the negative electrode of the first target to be balanced and the positive electrode of the second target to be balanced; The third overcurrent protection unit is arranged between the second target to be balanced and the switch control unit.

7. The multi-level active equalization circuit according to claim 6, characterized in that: It also includes a first filtering and voltage stabilizing unit and a second filtering and voltage stabilizing unit; A first end of the first filtering and stabilizing unit is connected to a connection point between the first overcurrent protection unit and the switch control unit, and a second end of the first filtering and stabilizing unit is connected to a connection point between the second overcurrent protection unit and the energy transfer unit; The first end of the second filtering and stabilizing unit is connected to the connection point between the second overcurrent protection unit and the energy transfer unit, and the second end of the second filtering and stabilizing unit is connected to the connection point between the third overcurrent protection unit and the switch control unit.

8. The multi-level active equalization circuit according to any one of claims 1 to 3, characterized in that: The controller outputs a PWM control signal to control the working state of the switch control circuit.

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