Energy storage converter and power supply

Abstract

An energy storage converter comprises a first resonant converter, a first end and a second end of a first side of the first resonant converter are respectively configured to be electrically connected with a first terminal and a second terminal of a battery pack, and the first end of a second side of the first resonant converter is electrically connected with a direct current bus at a first node; the first end and the second end of the first side of the second resonant converter are respectively configured to be electrically connected with the first terminal and the second terminal of the battery pack, and the second end of the second side of the second resonant converter is electrically connected with the bus at a second node; the second end of the second side of the first resonant converter, the first end of the second side of the second resonant converter and the DC bus are electrically connected to a third node; the first resonant converter and the second resonant converter are configured to balance a first voltage difference between the first node and the third node and a second voltage difference between the third node and the second node.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to an energy storage converter and a power supply. Background Art

[0002] In the current three-level circuit design of power conversion system (PCS), it is usually necessary to maintain the midpoint potential balance between the positive and negative DC bus. The midpoint potential balance is related to the performance and reliability of the circuit. The unbalanced midpoint potential may increase the harmonic distortion rate of the output voltage and current, thereby affecting the power quality.

[0003] In traditional solutions, an independent midpoint balancing circuit is usually added between the positive and negative busbars. The midpoint balancing circuit is generally composed of an inductor and two switching tubes, and the midpoint balance is achieved by controlling the conduction or disconnection of the two switching tubes. However, although the midpoint balancing circuit plays a role in balancing the midpoint potential in a variety of circuit designs, it also increases the algorithm workload in the software, thereby causing losses to the overall system operation. Summary of the invention

[0004] The first aspect of the present application provides an energy storage converter. The energy storage converter includes: a first resonant converter, wherein the first end of the first side of the first resonant converter is configured to be electrically connected to the first terminal of the battery pack, the second end of the first side of the first resonant converter is configured to be electrically connected to the second terminal of the battery pack, and the first end of the second side of the first resonant converter is electrically connected to the DC bus at a first node; a second resonant converter, wherein the first end of the first side of the second resonant converter is configured to be electrically connected to the first terminal of the battery pack, the second end of the first side of the second resonant converter is configured to be electrically connected to the second terminal of the battery pack, and the second end of the second side of the second resonant converter is electrically connected to the DC bus at a second node; the second end of the second side of the first resonant converter, the first end of the second side of the second resonant converter, and the DC bus are electrically connected to a third node; the first resonant converter and the second resonant converter are configured to balance the first voltage difference and the second voltage difference; wherein the first voltage difference U is defined as 1 is the voltage difference between the first node and the third node, the second voltage difference U 2 is the voltage difference between the third node and the second node.

[0005] In one or more embodiments of the present application, the energy storage inverter also includes: a controller, which is configured to adjust the power of the first resonant converter and / or the power of the second resonant converter according to the difference between the first voltage difference and the second voltage difference to adjust the voltage of the third node.

[0006] In the above scheme, there is no need to set up a midpoint balancing circuit. The switching frequency of the switching tube in the first resonant converter and / or the second resonant converter is controlled by the controller, thereby regulating the power distribution and voltage output of the two resonant converters to maintain the potential balance of the third node between the positive and negative DC bus bars, thereby ensuring the stable operation and good performance of the energy storage inverter.

[0007] In one or more embodiments of the present application, the energy storage converter also includes: a first capacitor and a second capacitor arranged on a DC bus; the first capacitor is electrically connected between the first node and the third node, and the second capacitor is electrically connected between the third node and the second node; wherein the first voltage difference is the voltage difference between the two ends of the first capacitor, and the second voltage difference is the voltage difference between the two ends of the second capacitor.

[0008] The first capacitor and the second capacitor are arranged between the positive and negative DC bus bars, and the first capacitor and the second capacitor can play the role of maintaining the DC bus voltage stable, filtering ripples and providing instantaneous energy.

[0009] In one or more embodiments of the present application, a capacitance difference between the first capacitor and the second capacitor is less than or equal to a first threshold.

[0010] By properly selecting and configuring the capacitance values ​​of the first capacitor and the second capacitor, the performance and reliability of the power electronic system can be improved, and it also helps to maintain the midpoint potential balance between the positive and negative DC busbars.

[0011] In one or more embodiments of the present application, the controller is configured as follows: in response to the battery pack entering or being in a charging state, the difference between the first voltage difference and the second voltage difference is outside the first voltage range, and the controller controls to increase the charging power of the target resonant converter corresponding to the first target voltage difference; wherein the first target voltage difference is the larger of the first voltage difference and the second voltage difference, the first resonant converter corresponds to the first voltage difference, and the second resonant converter corresponds to the second voltage difference.

[0012] Taking into account the battery pack's own power demand for charging power, when the difference between the first voltage difference and the second voltage difference is outside the first voltage range, the resonant converter corresponding to the larger voltage difference is preferentially adjusted to ensure that the battery's own charging power demand is met, thereby achieving rapid charging of the battery pack.

[0013] In one or more embodiments of the present application, the controller is configured as follows: in response to the battery pack entering or being in a charging state, the difference between the first voltage difference and the second voltage difference is outside the first voltage range, and the controller controls the reduction of the charging power of the target resonant converter corresponding to the second target voltage difference; wherein the second target voltage difference is the smaller of the first voltage difference and the second voltage difference, the first resonant converter corresponds to the first voltage difference, and the second resonant converter corresponds to the second voltage difference.

[0014] If the difference between the first voltage difference and the second voltage difference is outside the first voltage interval, and the first voltage difference is greater than the second voltage difference. In this case, the controller increases the equivalent resistance of the second resonant converter by controlling to reduce the power of the second resonant converter. In this way, the equivalent resistance between the third node and the second node increases, and the voltage division ratio on the DC bus increases, so that the second voltage difference increases, so that the difference between the first voltage difference and the second voltage difference decreases, and the midpoint potential between the positive and negative DC buses is kept balanced. Conversely, if the difference between the first voltage difference and the second voltage difference is outside the first voltage interval, and the first voltage difference is less than the second voltage difference. In this case, the controller balances the potential of the third node by controlling to reduce the power of the first resonant converter, which is not elaborated here.

[0015] In one or more embodiments of the present application, the controller is configured to: in response to the battery pack entering or being in a charging state, a first voltage difference exceeds the withstand voltage of the first capacitor, and the controller controls to increase the charging power of the first resonant converter and / or reduce the charging power of the second resonant converter; and / or, the controller is also configured to, in response to the battery pack entering or being in a charging state, a second voltage difference exceeds the withstand voltage of the second capacitor, and the controller controls to reduce the charging power of the first resonant converter and / or increase the charging power of the second resonant converter.

[0016] If the first voltage difference exceeds the withstand voltage of the first capacitor, the controller controls to increase the charging power of the first resonant converter, and / or reduce the charging power of the second resonant converter. In this way, it is equivalent to reducing the equivalent resistance of the first resonant converter between the first node and the third node, and / or increasing the equivalent resistance of the second resonant converter between the third node and the second node. The first voltage difference between the first node and the third node is reduced due to the reduction of the equivalent resistance voltage divider ratio, and the first voltage difference is reduced to a value lower than the withstand voltage of the first capacitor, and the second voltage difference is also increased accordingly, thereby realizing overvoltage protection for the first capacitor. The overvoltage protection of the second capacitor is similar to this, which will not be elaborated here.

[0017] In one or more embodiments of the present application, the energy storage inverter also includes: a two-phase AC-DC converter; the first end of the first side of the two-phase AC-DC converter is electrically connected to the first node, the second end of the first side of the two-phase AC-DC converter is electrically connected to the second node, the first live wire terminal and the neutral wire terminal of the second side of the two-phase AC-DC converter are configured to be electrically connected to the first load, the second live wire terminal and the neutral wire terminal of the second side of the two-phase AC-DC converter are configured to be electrically connected to the second load, and the neutral wire terminal is electrically connected to the third node; the first live wire terminal and the second live wire terminal of the second side of the two-phase AC-DC converter are also configured to be electrically connected to an AC power source; the controller is configured to: in response to the battery pack entering or being in a charging state, the controller controls the two-phase AC-DC converter to operate in a rectification mode; in response to the battery pack entering or being in a discharging state, the controller controls the two-phase AC-DC converter to operate in an inversion mode.

[0018] When the battery pack enters or is in the charging state, the controller controls the two-phase AC-DC converter to operate in the rectification mode. The two-phase AC-DC converter converts the AC power of the AC power source into DC power on the DC bus to charge and store energy for the battery pack. When the battery pack enters or is in the discharging state, the controller controls the two-phase AC-DC converter to operate in the inverter mode. The two-phase AC-DC converter converts the DC power on the DC bus into split-phase AC power on the first live wire terminal and the second live wire terminal to power the first load and the second load respectively.

[0019] In one or more embodiments of the present application, the controller is configured to: in response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the second voltage difference is outside the second voltage range, and the controller adjusts the power of the first resonant converter and / or the discharge power of the second resonant converter to adjust the voltage of the third node.

[0020] The controller controls the switching frequency of the switch tube in the first resonant converter and / or the second resonant converter to adjust the power of the first resonant converter and / or the discharge power of the second resonant converter to achieve midpoint potential balance during discharge of the battery pack, thereby ensuring stable operation and good performance of the entire energy storage inverter.

[0021] In one or more embodiments of the present application, the controller is configured as follows: in response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the second voltage difference is outside the second voltage range, and the controller controls to increase the discharge power of the target resonant converter corresponding to the third target voltage difference; wherein the third target voltage difference is the smaller of the first voltage difference and the second voltage difference, the first resonant converter corresponds to the first voltage difference, and the second resonant converter corresponds to the second voltage difference.

[0022] When the battery pack enters or is in a discharging state, if the difference between the first voltage difference and the second voltage difference is outside the second voltage range, and the first voltage difference is less than the second voltage difference, the first capacitor consumes more power and the second capacitor consumes less power. The controller controls to increase the discharge power of the first resonant converter to compensate for the power consumed by the first capacitor, thereby increasing the first voltage difference. In this way, the difference between the first voltage difference and the second voltage difference is reduced, and the midpoint between the positive and negative DC buses is restored to balance.

[0023] In one or more embodiments of the present application, the controller is configured as follows: in response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the second voltage difference is outside the second voltage range, and the controller controls the reduction of the discharge power of the target resonant converter corresponding to the fourth target voltage difference; wherein the fourth target voltage difference is the larger of the first voltage difference and the second voltage difference, the first resonant converter corresponds to the first voltage difference, and the second resonant converter corresponds to the second voltage difference.

[0024] In one or more embodiments of the present application, the controller is configured to: in response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the target voltage value exceeds a first voltage threshold, and the controller controls to reduce the discharge power of the first resonant converter; or, in response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the target voltage value is less than a second voltage threshold, and the controller increases the discharge power of the first resonant converter. Target voltage value U 目标 and the third voltage difference U 3 Satisfy: |U 目标 -1 / 2*U 3 |≤the third voltage threshold, the third voltage difference U 3 It is the voltage difference between the first node and the second node which is expected to be stabilized when the battery pack is discharged.

[0025] In this way, the controller adjusts the first resonant converter separately so that the first voltage difference is close to or equal to the target voltage value U 目标 In this way, the total DC voltage on the DC bus is kept stable and the midpoint balance of the third node is guaranteed.

[0026] In one or more embodiments of the present application, the controller is configured to: in response to the battery pack entering or being in a discharging state, the difference between the second voltage difference and the target voltage value exceeds a fourth voltage threshold, and the controller controls to reduce the discharge power of the second resonant converter; or, in response to the battery pack entering or being in a discharging state, the difference between the second voltage difference and the target voltage value is less than a fifth voltage threshold, and the controller controls to increase the discharge power of the second resonant converter; the target voltage value U 目标 and the third voltage difference U3 Satisfy: |U 目标 -1 / 2*U 3 |≤sixth voltage threshold, third voltage difference U 3 It is the voltage difference between the first node and the second node which is expected to be stabilized when the battery pack is discharged.

[0027] In this way, the controller adjusts the second resonant converter separately so that the second voltage difference is close to or equal to the target voltage value U 目标 In this way, the total DC voltage on the DC bus is kept stable and the midpoint balance of the third node is guaranteed.

[0028] In one or more embodiments of the present application, the rated output power of the first resonant converter and the rated output power of the second resonant converter are both less than a second threshold; wherein the range of the second threshold is [3KW, 6KW].

[0029] When the circuit board of the actual energy storage converter is integrated, since the rated output power of the first resonant converter and the second resonant converter are both small and similar, on the one hand, the size of the first resonant converter and the second resonant converter can be similar and small, ensuring the process smoothness during the integration of the PCS circuit board. On the other hand, the cost of two low-power resonant converters is often lower than that of one high-power resonant converter, so it is also more conducive to controlling and reducing process manufacturing costs. In this way, it brings dual benefits in process smoothness and cost.

[0030] In one or more embodiments of the present application, the first resonant converter is a bidirectional DC-DC resonant converter; and the second resonant converter is a bidirectional DC-DC resonant converter.

[0031] In response to the battery pack entering or being in a charging state, the controller adjusts the first resonant converter and the second resonant converter to step down the DC power on the DC bus to charge the battery pack. In response to the battery pack entering or being in a discharging state, the controller adjusts the first resonant converter and the second resonant converter to step up the DC power of the battery pack and output it to the DC bus.

[0032] In a second aspect, the present application provides a power supply, which includes a battery pack and an energy storage inverter as provided in any embodiment of the first aspect of the present application, and the battery pack is electrically connected to the energy storage inverter.

[0033] In one or more embodiments of the present application, the battery pack includes a connector; the connector includes a first terminal and a second terminal, the first resonant converter is electrically connected to the first terminal and the second terminal, respectively, and the second resonant converter is electrically connected to the first terminal and the second terminal, respectively; the first terminal is defined as the positive output terminal of the battery pack, and the second terminal is defined as the negative output terminal of the battery pack.

[0034] Compared with the prior art, the energy storage converter and power supply provided in the embodiment of the present application cleverly split the original single-channel high-power resonant converter into the above-mentioned first resonant converter and second resonant converter. The first side of the first resonant converter and the first side of the second resonant converter are connected in parallel and respectively connected to the battery pack, and the second sides of the first resonant converter and the second resonant converter are arranged in series on the DC bus. The first resonant converter and the second resonant converter replace the original high-power single-channel resonant converter to meet the voltage conversion requirements. In addition, the two resonant converters can dynamically balance the first voltage difference and the second voltage difference, and have the function of maintaining the midpoint balance between the DC buses, so the midpoint balance circuit designed separately in the traditional technology can be cancelled. In this way, the midpoint balance circuit in the traditional technology is omitted, which reduces the complexity of the circuit and reduces the algorithm workload of the energy storage converter software, thereby reducing the overall system operation loss, and also brings dual benefits in efficiency and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. The drawings described below are only some embodiments of the present application.

[0036] Figure 1 A schematic diagram of the structure of an energy storage converter provided in one embodiment of the present application;

[0037] Figure 2 A schematic diagram of the structure of a midpoint balancing circuit of the related technology provided by an embodiment of the present application;

[0038] Figure 3 A schematic diagram of the structure of an energy storage converter provided in another embodiment of the present application;

[0039] Figure 4 A schematic diagram of the structure of an energy storage converter provided in another embodiment of the present application;

[0040] Figure 5 A schematic diagram of the structure of an energy storage converter provided in another embodiment of the present application;

[0041] Figure 6 A phase diagram of split-phase alternating current provided in one embodiment of the present application;

[0042] Figure 7 A schematic diagram of the structure of an energy storage converter provided in another embodiment of the present application;

[0043] Figure 8 A schematic diagram of the structure of a power supply provided in one embodiment of the present application;

[0044] Fig. 9A schematic diagram of the structure of a power supply provided in another embodiment of the present application.

[0045] In the attached figure:

[0046] 10, first resonant converter; 20, second resonant converter; C1, first capacitor; C2, second capacitor; BUS, DC bus; BUS+, positive DC bus; BUS-, negative DC bus; N1, first node; N2, second node; N3, third node; U 1 , the first voltage difference; U 2 , the second voltage difference; 30, the controller; 40, the two-phase AC-DC converter; L1, the first live wire terminal; L2, the second live wire terminal; N, the neutral wire terminal; load1, the first load; load2, the second load; K, the protection switch; C3, the voltage-stabilizing capacitor; 100, the energy storage inverter; 200, the battery pack; 50, the connector; P+ / P-, the first terminal / the second terminal of the battery pack; 1000, the power supply.

[0047] In the drawings, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and detailed described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0049] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating the existence of three relationships. For example, A and / or B means: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0050] In the description of this application, connection can be direct connection, indirect connection through an intermediate medium, or internal connection between two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] In the embodiment of the present application, the first node, the second node and the third node are only defined for the convenience of describing the circuit structure, and the first node, the second node and the third node are not actual circuit units.

[0052] The embodiment of the present application provides an energy storage converter and a control method for the energy storage converter. The specific implementation of the embodiment of the present application is further described below in conjunction with the accompanying drawings.

[0053] Figure 1A schematic diagram of the structure of an energy storage inverter provided by an embodiment of the present application is shown. The energy storage inverter in the present application, for example, a split-phase energy storage inverter, is used to process single-phase AC power (such as a 120V / 240V split-phase system) and convert it into DC power, or convert DC power into split-phase AC power (with a phase difference of 180°). The energy storage inverter provided by the present application can be widely used in energy storage systems, renewable energy systems, electric vehicle charging piles and other fields. For example, the energy storage system includes a portable power supply.

[0054] like Figure 1 As shown, the energy storage converter 100 provided in the embodiment of the present application includes a first resonant converter 10 and a second resonant converter 20 .

[0055] The first end of the first side of the first resonant converter 10 is configured to be electrically connected to the first terminal P+ of the battery pack 200, the second end of the first side of the first resonant converter 10 is configured to be electrically connected to the second terminal P- of the battery pack 200, and the first end of the second side of the first resonant converter 10 is electrically connected to the DC bus BUS at the first node N1.

[0056] The first end of the first side of the second resonant converter 20 is configured to be electrically connected to the first terminal P+ of the battery pack 200, the second end of the first side of the second resonant converter 20 is configured to be electrically connected to the second terminal P- of the battery pack 200, and the second end of the second side of the second resonant converter 20 is electrically connected to the DC bus BUS at the second node N2.

[0057] The second end of the second side of the first resonant converter 10 , the first end of the second side of the second resonant converter 20 , and the DC bus BUS are electrically connected to a third node N3 .

[0058] The first resonant converter 10 and the second resonant converter 20 are configured to balance the first voltage difference U 1 and the second voltage difference U 2 .

[0059] Wherein, the first voltage difference U is defined 1 is the voltage difference between the first node N1 and the third node N3, the second voltage difference U 2 is the voltage difference between the third node N3 and the second node N2.

[0060] The battery pack 200 operates in two working states: charging and discharging. When entering or being in the charging state, the battery pack 200 receives direct current for charging and energy storage; when entering or being in the discharging state, the battery pack 200 outputs direct current to power the load.

[0061] In some examples, the second terminal P- of the battery pack 200 is also electrically connected to the reference ground GND to provide a stable reference potential for the circuit, reduce external interference, ensure normal operation of the circuit, and improve circuit safety.

[0062] In some embodiments of the present application, the DC bus BUS includes a high-voltage DC bus and a low-voltage DC bus. The low-voltage DC bus is a DC bus that connects the first side of the first resonant converter 10, the first side of the second resonant converter 20, and the first terminal P+ and the second terminal P- of the battery pack 200. In actual products, the power harness connecting the battery pack 200 and the energy storage inverter 100 corresponds to the low-voltage DC bus. Generally speaking, the energy storage inverter 100 is connected to the first terminal P+ of the battery pack 200 with a red power harness, and the energy storage inverter 100 is connected to the second terminal P- of the battery pack 200 with a black power harness.

[0063] The high-voltage DC bus is a DC bus connected to the second side of the first resonant converter 10 and the second side of the second resonant converter 20. In actual products, it can be understood that the high-voltage DC bus is a conductive copper wire printed on a circuit board corresponding to the energy storage converter 100.

[0064] It is understandable that the high voltage and low voltage in this article are relative. Simply put, the first side of the first resonant converter 10 is the low voltage side, and the second side of the first resonant converter 10 is the high voltage side.

[0065] It is understandable that the DC bus BUS involved in this application and the drawings mainly refers to the above-mentioned high-voltage DC bus. The DC bus BUS in this application is an intermediate link between the battery pack 200 and the load, and is used for energy storage, voltage conversion or power transmission. Taking the first terminal P+ of the battery pack 200 as an output of a positive voltage and the second terminal P- as an output of a negative voltage or zero voltage as an example, the DC bus BUS specifically includes the following: Figure 1 The positive DC bus BUS+ and the negative DC bus BUS- are shown.

[0066] The above-mentioned first node N1 is the intersection of the positive DC bus BUS+ and the first end of the second side of the first resonant converter 10, the second node N2 is the intersection of the negative DC bus BUS- and the second end of the second side of the second resonant converter 20, and the third node N3 is the midpoint between the positive and negative DC bus BUS+ and BUS-.

[0067] The resonant converter is a high-efficiency, high-power density power electronic converter widely used in the energy storage converter 100. The resonant converter can be used to achieve conversion between different voltage levels in a DC system. During specific operation, the resonant converter can implement soft switching technology through a resonant circuit, thereby improving efficiency, reducing switching losses, and reducing electromagnetic interference.

[0068] In the related art, in the energy storage converter, in order to meet the DC voltage level conversion requirements during the battery pack charging and discharging process, it is usually necessary to adopt a single-channel resonant converter with a large rated output power to achieve DC-DC (Direct Current) conversion. And, in order to maintain the midpoint potential balance of the DC bus, such as Figure 2 As shown, a midpoint balancing circuit consisting of an inductor L1 and two switching tubes Q1 and Q2 needs to be provided.

[0069] In the present application, the original single-channel high-power resonant converter is cleverly split into the above-mentioned first resonant converter 10 and the second resonant converter 20. The first side of the first resonant converter 10 and the first side of the second resonant converter 20 are connected in parallel and are electrically connected to the two terminals of the battery pack 200 respectively. The second side of the first resonant converter 10 and the second side of the second resonant converter 20 are arranged in series between the positive DC bus BUS+ and the negative DC bus BUS-.

[0070] The first resonant converter 10 and the second resonant converter 20 are used to replace the original high-power single-channel resonant converter to meet the voltage conversion requirements. In addition, the two resonant converters dynamically balance the first voltage difference U 1 and the second voltage difference U 2 , which has the function of maintaining the balance of the midpoint (i.e., the third node N3) between the DC buses BUS, so the midpoint balancing circuit designed separately in the related art can be cancelled, reducing the complexity of the circuit and the algorithm workload of the energy storage converter 100 in software, thereby reducing the overall system operation loss and bringing dual benefits in efficiency and cost.

[0071] See also Figure 3 According to some embodiments of the present application, the energy storage converter 100 further includes:

[0072] The controller 30 is configured to 1 and the second voltage difference U 2 The controller 30 adjusts the power of the first resonant converter 10 and / or the power of the second resonant converter 20 to adjust the voltage of the third node N3.

[0073] As an example of the present application, the controller 30 is a microcontroller unit (MCU) or a digital signal processor (DSP), etc. The controller 30 is responsible for receiving external signals and performing corresponding control according to a program.

[0074] The controller 30 samples the first voltage difference U by setting a sensor or a voltage divider circuit.1 and the second voltage difference U 2 After the first voltage difference U is detected 1 and the second voltage difference U 2 When the fluctuation occurs, it means that the potential of the third node N3 fluctuates. 1 and the second voltage difference U 2 If the difference between the first and second voltage difference U is large, that is, the potential fluctuation of the third node N3 is obvious, the potential of the third node N3 needs to be adjusted to balance the first voltage difference U 1 and the second voltage difference U 2 .

[0075] In this case, the controller 30 controls the switching frequency of the switch tubes in the first resonant converter 10 and / or the second resonant converter 20 to regulate the power distribution and voltage output of the two resonant converters. In this way, the potential balance of the third node N3 between the positive and negative DC bus bars BUS+ and BUS- is maintained, thereby ensuring the stable operation and good performance of the entire energy storage converter 100.

[0076] In this embodiment, the voltage output and power distribution of the two resonant converters are regulated to dynamically adjust and balance the voltage distribution on the DC bus, thereby reducing the first voltage difference U 1 and the second voltage difference U 2 The voltage difference between the two reduces the DC component of the AC current when the battery pack 200 is discharging to the outside, thereby reducing the reactive power loss of the electrical equipment and improving the stability and operating efficiency of the energy storage inverter 100.

[0077] See also Figure 4 According to some embodiments of the present application, the energy storage converter 100 further includes: a first capacitor C1 and a second capacitor C2 disposed on the DC bus BUS.

[0078] The first capacitor C1 is electrically connected between the first node N1 and the third node N3 , and the second capacitor C2 is electrically connected between the third node N3 and the second node N2 .

[0079] Among them, the first voltage difference U 1 is the voltage difference between the two ends of the first capacitor C1, and the second voltage difference U 2 is the voltage difference across the second capacitor C2.

[0080] In this embodiment, the first capacitor C1 and the second capacitor C2 are disposed between the positive and negative DC bus bars BUS+ and BUS-. The first capacitor C1 and the second capacitor C2 play the role of maintaining the DC bus voltage stable, filtering ripples and providing instantaneous energy.

[0081] It is understandable that when selecting the first capacitor C1 and the second capacitor C2, appropriate capacitance values ​​are selected according to the power requirements and ripple requirements of the energy storage converter 100 to improve system reliability.

[0082] In this embodiment, the capacitor is in the form of a single capacitor. In other embodiments, the capacitor is integrated by series, parallel or mixed capacitors, which is not limited in this application.

[0083] According to some embodiments of the present application, a capacitance difference between the first capacitor C1 and the second capacitor C2 is less than or equal to a first threshold.

[0084] When selecting specific capacitors, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are limited to be similar. In this way, the stability and filtering effect of the system are improved. Exemplarily, the first capacitor C1 and the second capacitor C2 of the same model are selected so that the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are close, for example, the difference in capacitance values ​​of the first capacitor C1 and the second capacitor C2 does not exceed ±15%.

[0085] The voltage fluctuation on the DC bus BUS usually needs to be smoothed by the first capacitor C1 and the second capacitor C2. If the capacitance values ​​of the two capacitors are similar, the voltage fluctuation is shared more evenly, avoiding excessive voltage or current stress on one capacitor and avoiding the midpoint potential jitter between the DC bus BUS.

[0086] When supplying energy to the load, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are similar, and the two share the energy demand more evenly, avoiding voltage sag or overshoot, which affects the midpoint balance between the DC bus BUS. If the capacitance values ​​of the first capacitor C1 and the second capacitor C2 differ greatly, it may cause uneven energy distribution, thereby affecting the dynamic performance of the energy storage converter 100.

[0087] In this embodiment, by reasonably selecting and configuring the capacitance values ​​of the first capacitor C1 and the second capacitor C2, the performance and reliability of the power electronic system are improved, which helps to maintain the midpoint potential balance between the positive and negative DC busbars.

[0088] According to some embodiments of the present application, the controller 30 is configured to:

[0089] In response to the battery pack 200 entering or being in a charging state, the first voltage difference U 1 and the second voltage difference U 2 If the difference between the target voltage and the first target voltage is outside the first voltage interval, the controller 30 controls to increase the charging power of the target resonant converter corresponding to the first target voltage difference.

[0090] The first target voltage difference is the first voltage difference U 1 and the second voltage difference U 2The larger one of the first resonant converter 10 and the first voltage difference U 1 Correspondingly, the second resonant converter 20 and the second voltage difference U 2 correspond.

[0091] The first voltage interval is, for example, [-20V, 20V]. The first voltage interval is determined according to the performance requirements of the energy storage converter 100 and is not limited here.

[0092] In this embodiment, if the battery pack 200 enters or is in a charging state, the first voltage difference U 1 and the second voltage difference U 2 The difference between them is outside the first voltage interval, indicating that the first voltage difference U 1 and the second voltage difference U 2 The difference between them is large, and the potential balance of the third node N3 is affected.

[0093] For example, if the first voltage difference U 1 and the second voltage difference U 2 The difference between them exceeds 20V, that is, the first voltage difference U 1 Greater than the second voltage difference U 2 , the controller 30 controls to increase the charging power of the first resonant converter 10 to reduce the first voltage difference U 1 Thus, the first voltage difference U 1 and the second voltage difference U 2 The difference between them can be reduced, so as to achieve the purpose of balancing the potential of the third node N3.

[0094] If the first voltage difference U 1 and the second voltage difference U 2 The difference between them is less than -20V, that is, the first voltage difference U 1 Less than the second voltage difference U 2 , the controller 30 controls to increase the charging power of the second resonant converter 20 to reduce the second voltage difference U 2 Thus, the first voltage difference U 1 and the second voltage difference U 2 The difference between them can be reduced, so as to achieve the purpose of balancing the potential of the third node N3.

[0095] The battery pack 200 enters or is in a charging state, and the working principle of the power regulation is as follows:

[0096] When it is necessary to reduce the first voltage difference U 1 When the charging power of the first resonant converter 10 is increased, it is equivalent to reducing the equivalent resistance of the first resonant converter 10 between the first node N1 and the third node N3.

[0097] When the battery pack 200 is charged, the total DC voltage provided between the positive and negative DC busbars BUS+ and BUS- is substantially stable, for example, stable at about 500V, and the equivalent resistance between the first node N1 and the third node N3 is reduced, so that the voltage division ratio between the first node N1 and the third node N3 for 500V is reduced, so that the first voltage difference U 1 The opposite principle is also true, which will not be elaborated here.

[0098] In this embodiment, considering the power demand of the battery pack 200 for the charging power, at the first voltage difference U 1 and the second voltage difference U 2 When the difference between them is outside the first voltage interval, the resonant converter corresponding to the larger voltage difference is adjusted to meet the charging power requirement of the battery itself, thereby achieving fast charging of the battery pack 200.

[0099] According to some embodiments of the present application, the controller 30 is configured to:

[0100] In response to the battery pack 200 entering or being in a charging state, the first voltage difference U 1 and the second voltage difference U 2 If the difference between the target voltage and the second target voltage is outside the first voltage interval, the controller 30 controls to reduce the charging power of the target resonant converter corresponding to the second target voltage difference.

[0101] The second target voltage difference is the first voltage difference U 1 and the second voltage difference U 2 The smaller one of the first resonant converter and the first voltage difference U 1 Correspondingly, the second resonant converter and the second voltage difference U 2 correspond.

[0102] In this embodiment, if the first voltage difference U 1 and the second voltage difference U 2 The difference between the first voltage and the second voltage is outside the first voltage interval, and the first voltage difference U 1 Greater than the second voltage difference U 2 In this case, the controller increases the equivalent resistance of the second resonant converter 20 by controlling to reduce the power of the second resonant converter 20 .

[0103] In this way, the equivalent resistance between the third node N3 and the second node N2 increases, and the voltage division ratio on the DC bus BUS increases, so that the second voltage difference U 2 Increases so that the first voltage difference U 1 and the second voltage difference U 2The difference between them is reduced, and the potential of the midpoint N3 between the positive and negative DC bus bars is kept balanced.

[0104] On the contrary, if the first voltage difference U 1 and the second voltage difference U 2 The difference between the first voltage and the second voltage is outside the first voltage interval, and the first voltage difference U 1 Less than the second voltage difference U 2 In this case, the controller 30 balances the potential of the third node N3 by controlling to reduce the power of the first resonant converter 10, which will not be described in detail here.

[0105] In some examples, the battery pack 200 enters or is in a charging state, and the total DC voltage on the DC bus BUS is stabilized, for example, at 500 V. The first voltage difference U 1 and the second voltage difference U 2 The difference between the first voltage difference U and the second voltage difference U means the extent to which the voltage of the third node N3 deviates from half of the total DC voltage value (for example, 250V). 1 and the second voltage difference U 2 The difference between them is outside the first voltage interval, indicating that the deviation between the voltage of the third node N3 and half of the total DC voltage is large, and it is necessary to balance the voltage of the third node N3 to close to or approximately half of the total DC voltage.

[0106] For example, the battery pack 200 enters or is in a charging state, and the first voltage interval is, for example, [-20V, 20V]. 1 =255V, the second voltage difference U 2 =245V, the first voltage difference U 1 and the second voltage difference U 2 If the difference between the first voltage difference U and the second voltage difference U does not exceed [-20V, 20V], the first resonant converter 10 and the second resonant converter 20 do not need to be controlled. 1 =270V, the second voltage difference U 2 =230V, the first voltage difference U 1 and the second voltage difference U 2 The difference between them exceeds [-20V, 20V].

[0107] In this case, the controller 30 only controls to increase the charging power of the first resonant converter 10, so that the equivalent resistance between the first node N1 and the third node N3 is reduced, and the voltage division ratio on the DC bus BUS is reduced, so that the first voltage difference U 1 Reduced to about 250V. Due to the influence on the voltage division ratio of 500V, the second voltage difference U 2 will also increase to about 250V, making the first voltage difference U1 and the second voltage difference U 2 The difference between them is reduced, and the potential of the midpoint N3 between the positive and negative DC bus bars is kept balanced.

[0108] Alternatively, the controller 30 only controls to reduce the charging power of the second resonant converter 20, so that the equivalent resistance between the third node N3 and the second node N2 increases, and the voltage division ratio on the DC bus BUS increases, so that the second voltage difference U 2 Increases to about 250V. Due to the influence on the voltage division ratio of 500V, the first voltage difference U 1 will also decrease to about 250V, so that the first voltage difference U 1 and the second voltage difference U 2 The difference between them is reduced, and the potential of the midpoint N3 between the positive and negative DC bus bars is kept balanced.

[0109] Alternatively, the controller 30 simultaneously controls to increase the charging power of the first resonant converter 10 and controls to reduce the charging power of the second resonant converter 20, so that the equivalent resistance between the first node N1 and the third node N3 is reduced, and the equivalent resistance between the third node N3 and the second node N2 is increased. Under the action of the equivalent resistance voltage division, the first voltage difference U 1 Reduced to about 250V, the second voltage difference U 2 Increased to about 250V, the potential of the midpoint N3 between the positive and negative DC bus bars is kept balanced.

[0110] According to some embodiments of the present application, the controller 30 is configured to:

[0111] In response to the battery pack 200 entering or being in a charging state, the first voltage difference U 1 When the voltage exceeds the withstand voltage of the first capacitor C1, the controller 30 controls to increase the charging power of the first resonant converter 10 and / or reduce the charging power of the second resonant converter 20;

[0112] and / or,

[0113] The controller 30 is further configured to, in response to the battery pack 200 entering or being in a charging state, 2 When the voltage exceeds the withstand voltage of the second capacitor C2 , the controller 30 controls to reduce the charging power of the first resonant converter 10 and / or increase the charging power of the second resonant converter 20 .

[0114] When the energy storage converter is working, the voltage value on the first capacitor C1 and the second capacitor C2 is generally not allowed to exceed its withstand voltage value, which is the maximum voltage that the capacitor can safely withstand. If the voltage across the capacitor exceeds its withstand voltage value, the capacitor may be damaged and lose its energy storage capacity, which may cause circuit failure in severe cases.

[0115] Therefore, in this embodiment, when the battery pack 200 enters or is in the charging state, the controller 30 detects the first voltage difference U 1 Whether it exceeds the withstand voltage of the first capacitor C1, and the second voltage difference U 2 Whether it exceeds the withstand voltage of the second capacitor C2.

[0116] If the first voltage difference U 1 exceeds the withstand voltage of the first capacitor C1, for example, the first voltage difference U 1 The first voltage difference U between the first node N1 and the third node N3 is 350V, the withstand voltage value of the first capacitor C1 is 330V, and the controller 30 controls to increase the charging power of the first resonant converter 10, and / or reduce the charging power of the second resonant converter 20. In this way, the equivalent resistance of the first resonant converter 10 between the first node N1 and the third node N3 is reduced, and the equivalent resistance of the second resonant converter 20 between the third node N3 and the second node N2 is increased. 1 As the equivalent resistance voltage division ratio decreases, the first voltage difference U 1 The second voltage difference U 2 The voltage of the first capacitor C1 also increases accordingly, thereby achieving overvoltage protection for the components of the first capacitor C1.

[0117] If the second voltage difference U 2 If the voltage difference U between the third node N3 and the second node N2 exceeds the withstand voltage of the second capacitor C2, the controller 30 controls to increase the charging power of the second resonant converter 20 and / or reduce the charging power of the first resonant converter 10. In this way, the equivalent resistance of the second resonant converter 20 between the third node N3 and the second node N2 is reduced, and the equivalent resistance of the first resonant converter 10 between the first node N1 and the third node N3 is increased. 2 As the equivalent resistance voltage division ratio decreases, the second voltage difference U 2 The first voltage difference U 1 The voltage of the second capacitor C2 also increases accordingly, thereby achieving overvoltage protection for the components of the second capacitor C2.

[0118] See also Figure 5 (The controller 30 is not shown). According to some embodiments of the present application, the energy storage converter 100 further includes: a two-phase AC-DC converter 40 .

[0119] A first end of the first side of the two-phase AC-DC converter 40 is electrically connected to the first node N1 , and a second end of the first side of the two-phase AC-DC converter 40 is electrically connected to the second node N2 .

[0120] The first live terminal L1 and the neutral terminal N on the second side of the two-phase AC-DC converter 40 are configured to be electrically connected to the first load load1, the second live terminal L2 and the neutral terminal N on the second side of the two-phase AC-DC converter 40 are configured to be electrically connected to the second load load2, and the neutral terminal N is electrically connected to the third node N3.

[0121] The first live terminal L1 and the second live terminal L2 of the second side of the two-phase AC-DC converter 40 are also configured to be electrically connected to an AC power source.

[0122] The controller 30 is configured as follows: in response to the battery pack 200 entering or being in a charging state, the controller 30 controls the two-phase AC-DC converter 40 to operate in a rectification mode; in response to the battery pack 200 entering or being in a discharging state, the controller 30 controls the two-phase AC-DC converter 40 to operate in an inverter mode.

[0123] In this embodiment, the dual-phase AC-DC converter 40 is composed of two independent single-phase AC (Alternating Current)-DC converters, which process two phases of the AC power supply respectively. The dual-phase AC-DC converter 40 is used to convert AC power into DC power, or convert DC power into AC power.

[0124] The AC power supply is used to provide AC power. In this embodiment, the AC power supply is a mains power grid, or other power supply capable of outputting AC power, such as a generator, etc., which is not limited here.

[0125] In some embodiments of the present application, the battery pack 200 is provided in a portable power supply, and the portable power supply supplies power to a first load load1 and a second load load2. For example, the first load and the second load include: power tools, laptop computers, hair dryers, induction cookers, rice cookers, car refrigerators, hair dryers, microwave ovens, etc., which are not strictly limited here.

[0126] During specific operation: when the battery pack 200 enters or is in a charging state, the controller 30 controls the two-phase AC-DC converter 40 to operate in a rectification mode. The two-phase AC-DC converter 40 converts the AC power of the AC power source into DC power on the DC bus BUS to charge and store energy for the battery pack 200; when the battery pack 200 enters or is in a discharging state, the controller 30 controls the two-phase AC-DC converter 40 to operate in an inverter mode. The two-phase AC-DC converter 40 converts the DC power on the DC bus BUS into split-phase AC power (with a phase difference of 180°) on the first live wire terminal L1 and the second live wire terminal L2, and supplies power to the first load load1 and the second load load2 respectively.

[0127] Continue as Figure 5As shown, in this embodiment, the energy storage converter 100 is also configured to be electrically connected to the first AC output interface, the second AC output interface, and the AC input interface. For example, the energy storage converter 100 is electrically connected to the first AC output interface, the second AC output interface, and the AC input interface through power harnesses. The first AC output interface, the second AC output interface, and the AC input interface are provided on a portable power supply, which includes the energy storage converter 100. The first AC output interface, the second AC output interface, and the AC input interface are electrically connected to the energy storage converter 100 through the wires drawn from the energy storage converter 100.

[0128] The first AC output interface is used to connect the first load load1. The live terminal of the first AC output interface is electrically connected to the first live terminal L1 of the second side of the two-phase AC-DC converter 40, and the neutral terminal of the first AC output interface is electrically connected to the neutral terminal N of the second side of the two-phase AC-DC converter 40.

[0129] The second AC output interface is used to connect the second load load2. The live terminal of the second AC output interface is electrically connected to the second live terminal L2 of the second side of the two-phase AC-DC converter 40, and the neutral terminal of the second AC output interface is electrically connected to the neutral terminal N of the second side of the two-phase AC-DC converter 40.

[0130] The AC input interface is used to connect an AC power source. A first terminal of the AC input interface is electrically connected to a first live wire terminal L1 of a second side of the dual-phase AC-DC converter 40 , and a second terminal is electrically connected to a second live wire terminal L2 of a second side of the dual-phase AC-DC converter 40 .

[0131] The AC input interface also includes a ground terminal PE. Thus, when the AC power source provides the AC power source to the second side of the dual-phase AC-DC converter 40 through the AC input interface, the ground terminal PE is grounded to protect the AC input interface.

[0132] In order to ensure flexible switching of the load access power supply state and the AC power input charging state of the dual-phase AC-DC converter 40, in some embodiments of the present application, corresponding control switches are set on the connection paths between the first AC output interface, the second AC output interface and the AC input interface and the dual-phase AC-DC converter 40, for example Figure 5 As shown, the corresponding circuits can be flexibly connected or disconnected according to needs.

[0133] According to some embodiments of the present application, the controller 30 is configured to:

[0134] In response to the battery pack 200 entering or being in a discharge state, the first voltage difference U 1 and the second voltage difference U 2When the difference between the first and second nodes N3 is outside the second voltage interval, the controller 30 adjusts the power of the first resonant converter 10 and / or the discharge power of the second resonant converter 20 to adjust the voltage of the third node N3.

[0135] The second voltage range is, for example, [-20V, 20V] or [-25V, 25V]. The second voltage range may be determined according to the performance requirements of the energy storage converter 100 and is not limited here.

[0136] In this embodiment, when the battery pack 200 enters or is in the discharge state, the third node N3 is prone to potential oscillation and fluctuation in the scenario where the two loads connected to the second side of the two-phase AC-DC converter 40 have uneven power, or the first load load1 / the second load load2 is switched from full load to no load, etc. In this case, the controller 30 maintains the voltage balance of the third node N3 by adjusting the power of the first resonant converter 10 and / or the discharge power of the second resonant converter 20.

[0137] As an example, when the load powers of the first load load1 and the second load load2 are uneven, for example, the rated power of the first load load1 is 800 W, and the rated power of the second load load2 is 200 W. In this case, the first capacitor C1 and the second capacitor C2 are prone to uneven voltage, and the potential of the third node N3 oscillates and fluctuates, affecting the quality of the alternating current output by the two-phase AC-DC converter 40, and easily causing distortion of the output voltage.

[0138] In this example, the controller 30 adjusts the power of the first resonant converter 10 and / or the discharge power of the second resonant converter 20 by controlling the switching frequency of the switch tube in the first resonant converter 10 and / or the second resonant converter 20. In this way, the midpoint potential imbalance caused by uneven load during the discharge of the battery pack 200 is adjusted, thereby ensuring the stable operation and good performance of the entire energy storage converter 100.

[0139] According to some embodiments of the present application, the controller 30 is configured to:

[0140] In response to the battery pack 200 entering or being in a discharge state, the first voltage difference U 1 and the second voltage difference U 2 If the difference between the first and second voltage intervals is outside the second voltage interval, the controller 30 controls to increase the discharge power of the target resonant converter corresponding to the third target voltage difference. The third target voltage difference is the first voltage difference U 1 and the second voltage difference U 2 The smaller one of the first resonant converter 10 and the first voltage difference U 1 Correspondingly, the second resonant converter 20 and the second voltage difference U 2 correspond.

[0141] Specifically, when the battery pack 200 enters or is in a discharge state, if the first voltage difference U 1 and the second voltage difference U 2 The difference between the first voltage difference U 1 Less than the second voltage difference U 2 The first capacitor C1 consumes more power, and the second capacitor C2 consumes less power.

[0142] In this case, the controller 30 controls to increase the discharge power of the first resonant converter 10 to compensate for the electric energy consumed by the first capacitor C1, thereby increasing the first voltage difference U 1 In this way, the first voltage difference U is reduced. 1 and the second voltage difference U 2 The difference between the positive and negative DC busbars is restored to balance at the midpoint N3.

[0143] If the first voltage difference U 1 and the second voltage difference U 2 The difference between the first voltage difference U 1 Greater than the second voltage difference U 2 The first capacitor C1 consumes less power, and the second capacitor C2 consumes more power.

[0144] In this case, the controller 30 controls to increase the discharge power of the second resonant converter 20 to compensate for the energy loss of the second capacitor C2, thereby increasing the second voltage difference U 2 Thus, the first voltage difference U 1 and the second voltage difference U 2 The difference between them is reduced, and the potential of the midpoint N3 between the positive and negative DC bus bars is restored to balance.

[0145] According to some embodiments of the present application, the controller 30 is configured to:

[0146] In response to the battery pack 200 entering or being in a discharge state, the first voltage difference U 1 and the second voltage difference U 2 If the difference between the first and second voltage intervals is outside the second voltage interval, the controller 30 controls to reduce the discharge power of the target resonant converter corresponding to the fourth target voltage difference. The fourth target voltage difference is the first voltage difference U 1 and the second voltage difference U 2 The larger one of the first resonant converter 10 and the first voltage difference U 1 Correspondingly, the second resonant converter 20 and the second voltage difference U 2 correspond.

[0147] Specifically, when the battery pack 200 enters or is in a discharge state, if the first voltage difference U 1 and the second voltage difference U 2 The difference between the first voltage difference U 1 Less than the second voltage difference U 2 The first capacitor C1 consumes more power, and the second capacitor C2 consumes less power.

[0148] In this case, the controller 30 controls to reduce the discharge power of the second resonant converter 20, thereby reducing the second voltage difference U 2 In this way, the first voltage difference U is reduced. 1 and the second voltage difference U 2 The difference between the positive and negative DC busbars is restored to balance at the midpoint N3.

[0149] If the first voltage difference U 1 and the second voltage difference U 2 The difference between the first voltage difference U 1 Greater than the second voltage difference U 2 The first capacitor C1 consumes less power, and the second capacitor C2 consumes more power.

[0150] In this case, the controller 30 controls to reduce the discharge power of the first resonant converter 10, thereby reducing the first voltage difference U 1 Thus, the first voltage difference U 1 and the second voltage difference U 2 The difference between them is reduced, and the potential of the midpoint N3 between the positive and negative DC bus bars is restored to balance.

[0151] The midpoint balance principle under the discharge state is introduced in detail below.

[0152] As an example, a first load load1 is connected between the first live wire terminal L1 and the neutral wire terminal N on the second side of the two-phase AC-DC converter 40, and the rated power of the first load load1 is 800W; a second load load2 is connected between the second live wire terminal L2 and the neutral wire terminal N on the second side of the two-phase AC-DC converter 40, and the rated power of the second load load2 is 200W.

[0153] The phases of the single-phase AC power outputted from the first live wire terminal L1 and the second live wire terminal L2 of the second side of the two-phase AC-DC converter 40 are 180° apart. If the frequency of the AC power outputted from the first live wire terminal L1 and the second live wire terminal L2 is 50HZ, then one AC cycle is 0.02 seconds. In this example, the second voltage interval is [-20V, 20V].

[0154] Combination Figure 6 As shown, when the battery pack 200 enters or is in the discharge state, within 0.01 seconds of the first half cycle (such as t1), the first live wire terminal L1 draws power from the first capacitor C1 to supply the first load load1, and the second live wire terminal L2 draws power from the second capacitor C2 to supply the second load load2. Since the rated power of the first load load1 is greater than the rated power of the second load load2, the neutral terminal N, that is, the third node N3, may shift to the phase with a heavier load, resulting in a change in the midpoint voltage of N3 between the positive and negative DC busbars (upward deviation), thereby causing the first voltage difference U 1 and the second voltage difference U 2 The difference between them is less than -20V, which affects the power supply quality of the load.

[0155] In this case, since the electric energy Q of the first capacitor C1 is Q=C*U 1 When the battery pack 200 is discharged, the electric energy charged by the first resonant converter 10 to the first capacitor C1 is: W = P (LLC1) * t, and the controller 30 controls to increase the discharge power of the first resonant converter 10 to achieve compensation for the electric energy of the first capacitor C1, thereby increasing the first voltage difference U 1 effect.

[0156] Similarly, the controller 30 controls to reduce the discharge power of the second resonant converter 20, thereby reducing the second voltage difference U 2 The effect is that the first voltage difference U 1 and the second voltage difference U 2 The difference between them is reduced to [-20V, 20V], and the potential of the midpoint of N3 between the positive and negative DC bus bars is restored to balance.

[0157] In the second half of the cycle (such as t2), within 0.01 seconds, the first live wire terminal L1 draws power from the second capacitor C2 to supply the first load load1, and the second live wire terminal L2 draws power from the first capacitor C1 to supply the second load load2. Since the rated power of the first load load1 is greater than the rated power of the second load load2, the neutral terminal N, that is, the third node N3, will shift toward the phase with a heavier load, causing the midpoint voltage between the positive and negative DC busbars BUS+ and BUS- to change (downward), thereby causing the first voltage difference U 1 and the second voltage difference U 2 If it is greater than 20V, the power supply quality of the load will be affected.

[0158] In this case, since the electric energy Q of the first capacitor C1 is Q=C*U 1When the battery pack 200 is discharged, the electric energy charged by the first resonant converter 10 to the first capacitor C1 is: W = P (LLC1) * t. The controller 30 controls to reduce the discharge power of the first resonant converter 10, which can reduce the charging electric energy of the first capacitor C1, thereby reducing the first voltage difference U 1 effect.

[0159] Similarly, the controller 30 controls to increase the discharge power of the second resonant converter 20, thereby increasing the second voltage difference U 2 The effect is that the first voltage difference U 1 and the second voltage difference U 2 The difference between them is reduced, and the midpoint potential between the positive and negative DC bus bars is restored to balance.

[0160] As another example, a first load load1 is connected between the first live wire terminal L1 and the neutral wire terminal N on the second side of the two-phase AC-DC converter 40, and the rated power of the first load load1 is 500W. A second load load2 is connected between the second live wire terminal L2 and the neutral wire terminal N on the second side of the two-phase AC-DC converter 40, and the rated power of the second load load2 is 500W.

[0161] In the first half cycle (such as t1), within 0.01 seconds, if the first load load1 between the first live terminal L1 and the neutral terminal N of the second side of the two-phase AC-DC converter 40 is switched from full load to no load (no load connected), the first voltage difference U 1 Increase.

[0162] In this case, the controller 30 reduces the discharge power of the first resonant converter 10 by controlling to reduce the charging energy of the first capacitor C1, so that the first voltage difference U 1 The controller 30 controls to increase the discharge power of the second resonant converter 20 to increase the charging energy of the second capacitor C2, thereby making the second voltage difference U 2 The voltage of the third node N3 increases, and finally the effect of adjusting the potential balance of the third node N3 is achieved. The specific implementation principle can be found in the above example, which will not be elaborated here.

[0163] According to some embodiments of the present application, the controller 30 is configured to:

[0164] In response to the battery pack 200 entering or being in a discharge state, the first voltage difference U 1 When the difference between the voltage value and the target voltage value exceeds the first voltage threshold, the controller 30 controls to reduce the discharge power of the first resonant converter 10;

[0165] or,

[0166] In response to the battery pack 200 entering or being in a discharge state, the first voltage difference U 1 If the difference between the target voltage value and the target voltage value is smaller than the second voltage threshold, the controller 30 increases the discharge power of the first resonant converter 10 .

[0167] Target voltage value U 目标 and the third voltage difference U 3 Satisfy: |U 目标 -1 / 2*U 3 |≤the third voltage threshold, the third voltage difference U 3 It is the voltage difference between the first node N1 and the second node N2 which is expected to be stabilized when the battery pack 200 is discharged.

[0168] In practical applications, when the battery pack 200 enters or is in a discharge state, it is necessary to keep the total DC voltage on the DC bus BUS stable to ensure the normal operation of the load equipment and the smooth operation of the system. 1 and the second voltage difference U 2 On the basis of balance, a target voltage value U is further set 目标 , based on the target voltage value, adjust the first voltage difference U 1 Close to or equal to the target voltage value, adjust the second voltage difference U 2 Close to or equal to the target voltage value U 目标 , further maintaining the voltage stability on the DC bus BUS.

[0169] In some embodiments, the absolute value of the difference between the target voltage value and half of the total value of the DC voltage expected to be stable on the DC bus BUS is less than or equal to the third voltage threshold. The third voltage threshold is determined according to the performance requirements of the energy storage converter 100 and is not limited here. For example, if the voltage on the DC bus BUS is expected to be stable at 500V, and the third voltage threshold is set to 5V, then the range of the target voltage value is [245V, 255V]. It is understandable that when the battery pack 200 enters or is in a discharge state, the third voltage difference U 3 is the voltage expected to be stabilized on the DC bus BUS, that is, the voltage difference expected to be stabilized between the first node N1 and the second node N2. In some embodiments of the present application, when the second node N2 is at zero potential, the absolute value of the difference between the target voltage value and the voltage value of the third node N3 is less than or equal to the third voltage threshold.

[0170] In some embodiments, the controller 30 monitors the first voltage difference U 1 , calculate U 1 with U 目标 The difference, and respond to U 1 and U 目标The difference between U and V is greater than the first voltage threshold, and the controller 30 controls to reduce the discharge power of the first resonant converter 10. 1 and U 目标 When the difference between and is smaller than the second voltage threshold, the discharge power of the first resonant converter 10 is controlled to be increased.

[0171] For example, the battery pack 200 enters or is in a discharging state, and it is expected that the voltage on the DC bus BUS is stabilized at 500V, that is, the third voltage difference U 3 is 500V, U 目标 Set to the third voltage difference U 3 Half of that, i.e. 250V, the first voltage threshold is 20V, and the second voltage threshold is -20V. The present application includes the following embodiments:

[0172] 1) U 1 =265V, U 1 with U 目标 The difference does not exceed the first voltage threshold 20V, U 1 with U 目标 The difference of 15V does not exceed the first voltage threshold 20V, U 1 with U 目标 If the difference 15V is not less than the second voltage threshold −20V, the controller 30 maintains the original control of the first resonant converter 10 .

[0173] 2) U 1 =280V, U 1 with U 目标 The difference 30V exceeds the first voltage threshold 20V, and the controller 30 controls the discharge power of the first resonant converter 10 to decrease to reduce U 1 to close to or equal to 250V.

[0174] 3) U 1 =220V, U 1 with U 目标 The difference of -30V is less than the second voltage threshold -20V, and the controller 30 controls the discharge power of the first resonant converter 10 to increase U 1 to close to or equal to 250V.

[0175] In this way, the controller 30 adjusts the first resonant converter 10 separately so that the first voltage difference U 1 Close to or equal to the target voltage value U 目标 In this way, the total value of the DC voltage on the DC bus BUS is kept stable, and the midpoint balance of the third node N3 is ensured.

[0176] According to some embodiments of the present application, the controller 30 is configured to:

[0177] In response to the battery pack 200 entering or being in a discharge state, the second voltage difference U 2 When the difference between the voltage value and the target voltage value exceeds a fourth voltage threshold, the controller 30 controls to reduce the discharge power of the second resonant converter 20;

[0178] or,

[0179] In response to the battery pack 200 entering or being in a discharge state, the second voltage difference U 2 If the difference between the target voltage value and the target voltage value is smaller than the fifth voltage threshold, the controller 30 controls the discharge power of the second resonant converter 20 to increase.

[0180] Target voltage value U 目标 and the third voltage difference U 3 Satisfy: |U 目标 -1 / 2*U 3 |≤sixth voltage threshold, third voltage difference U 3 It is the voltage difference between the first node N1 and the second node N2 which is expected to be stabilized when the battery pack 200 is discharged.

[0181] In some embodiments, the absolute value of the difference between the target voltage value and half of the total value of the DC voltage expected to be stable on the DC bus BUS is less than or equal to the sixth voltage threshold, which is determined according to the performance requirements of the energy storage converter 100 and is not limited here. For example, if the voltage on the DC bus BUS is expected to be stable at 500V, and the sixth voltage threshold is set to 5V, then the range of the target voltage value is [245V, 255V]. It is understandable that when the battery pack 200 enters or is in a discharge state, the third voltage difference U 3 is the voltage that is expected to be stabilized on the DC bus BUS, that is, the voltage difference between the first node N1 and the second node N2 that is expected to be stabilized.

[0182] In some embodiments, the controller 30 monitors the second voltage difference U 2 , calculate U 2 with U 目标 The difference, and respond to U 2 and U 目标 The difference between U and V is greater than the fourth voltage threshold, and the controller 30 controls to reduce the discharge power of the second resonant converter 20. 2 and U 目标 When the difference between and is less than the fifth voltage threshold, the discharge power of the second resonant converter 20 is controlled to be increased.

[0183] For example, the battery pack 200 enters or is in a discharging state, and it is expected that the voltage on the DC bus BUS is stabilized at 500V, that is, the third voltage difference U 3 is 500V, U 目标Set to the third voltage difference U 3 The fourth voltage threshold is 20V, and the fifth voltage threshold is -20V. The present application includes the following embodiments:

[0184] 1) U 2 =265V, U 2 with U 目标 The difference of 15V does not exceed the fourth voltage threshold 20V, U 2 with U 目标 If the difference 15V is not less than the fifth voltage threshold −20V, the controller 30 maintains the original control of the second resonant converter 20 .

[0185] 2) U 2 =280V, U 2 with U 目标 The difference 30V exceeds the fourth voltage threshold 20V, and the controller 30 controls the discharge power of the second resonant converter 20 to decrease to reduce U 2 to close to or equal to 250V.

[0186] 3) U 2 =220V, U 2 with U 目标 The difference -30V is less than the fifth voltage threshold -20V, and the controller 30 controls the discharge power of the second resonant converter 20 to increase U 2 to close to or equal to 250V.

[0187] In this way, the controller 30 adjusts the second resonant converter 20 separately so that the second voltage difference U 2 Close to or equal to the target voltage value U 目标 In this way, the total value of the DC voltage on the DC bus BUS is kept stable, and the midpoint balance of the third node N3 is ensured.

[0188] According to some embodiments of the present application, the rated output power of the first resonant converter 10 and the rated output power of the second resonant converter 20 are both less than the second threshold. In some embodiments of the present application, the second threshold ranges from [3KW, 6KW].

[0189] In the energy storage converter of the related art, in order to meet the DC voltage level conversion requirements during the charging and discharging process of the battery pack 200, a single-channel resonant converter with a relatively large rated output power is adopted, and its rated output power, for example, is 7.2KW. In actual applications, the size of the resonant converter is often related to its rated output power. The larger its rated output power, the larger the corresponding size and the higher the price.

[0190] In this embodiment, after the original single-channel high-power resonant converter is cleverly split into two smaller-power resonant converters, the rated output powers of the first resonant converter 10 and the second resonant converter 20 are further limited to be in the range of [3KW, 6KW].

[0191] In this way, when the circuit board of the actual energy storage converter 100 is integrated and manufactured, since the rated output powers of the first resonant converter 10 and the second resonant converter 20 are both small and similar in power, on the one hand, the sizes of the first resonant converter 10 and the second resonant converter 20 can be similar and small, ensuring the process smoothness during the integrated manufacturing of the PCS circuit board. On the other hand, the cost of two low-power resonant converters is often lower than that of one high-power resonant converter, so it is also more conducive to controlling and reducing process manufacturing costs. In this way, it brings dual benefits in process smoothness and cost.

[0192] According to some embodiments of the present application, the first resonant converter 10 is a bidirectional DC-DC resonant converter, and the second resonant converter 20 is a bidirectional DC-DC resonant converter.

[0193] In response to the battery pack 200 entering or being in a charging state, the controller 30 adjusts the first resonant converter 10 and the second resonant converter 20 to step down the DC power on the DC bus BUS to charge the battery pack 200 .

[0194] More specifically, under the regulation of the controller 30, the first resonant converter 10 steps down the DC voltage between the first node N1 and the third node N3 and charges the battery pack 200, and the second resonant converter 20 steps down the DC voltage between the third node N3 and the second node N2 and charges the battery pack 200.

[0195] In response to the battery pack 200 entering or being in a discharge state, the controller 30 adjusts the first resonant converter 10 and the second resonant converter 20 to boost the DC power of the battery pack 200 and output the boosted DC power to the DC bus BUS.

[0196] More specifically, under the regulation of the controller 30, the first resonant converter 10 boosts the DC power at both ends of the battery pack 200 and outputs it to the first node N1 and the second node N2, and the second resonant converter 20 boosts the DC power at both ends of the battery pack 200 and outputs it to the third node N3 and the second node N2.

[0197] like Figure 7 As shown (controller 30 is not shown), in some examples, the energy storage converter 100 further includes a protection switch K.

[0198] The first end of the protection switch K is configured to be electrically connected to the first terminal P+ of the battery pack 200 , and the second end of the protection switch K is configured to be electrically connected to the first end of the first side of the first resonant converter 10 and the first end of the first side of the second resonant converter 20 .

[0199] In some examples, the protection switch K includes a fuse or a metal-oxide-semiconductor field-effect transistor (MOSFET). Of course, in other examples, the switch may also be other types of switches, which is not limited in the present application.

[0200] In this embodiment, the protective switch K is taken as a fuse. By setting the fuse, when an overcurrent or short circuit occurs in the circuit, the fuse is quickly blown to cut off the power supply, thereby protecting the circuit from damage caused by the overcurrent or short circuit. In normal operation, the fuse remains closed to ensure normal energy storage inverter operation.

[0201] Further, in some embodiments, continuing as Figure 7 As shown, the energy storage converter 100 further includes a voltage stabilizing capacitor C3.

[0202] The first electrode of the voltage-stabilizing capacitor C3 is configured to be electrically connected to the first terminal P+ of the battery pack 200 , and the second electrode of the voltage-stabilizing capacitor C3 is configured to be electrically connected to the second terminal P− of the battery pack 200 .

[0203] In this embodiment, a voltage stabilizing capacitor C3 is provided between the first terminal P+ and the second terminal P- of the battery pack 200. In this way, if the voltage of the battery pack 200 fluctuates (such as instantaneous voltage spikes or fluctuations) during the charging and discharging process, the voltage stabilizing capacitor C3 can absorb the instantaneous voltage fluctuation, making the voltage smoother and more stable, and also helps to ensure the midpoint balance between the DC buses.

[0204] In addition, high-frequency noise may be generated during the charging and discharging process of the battery pack 200. Setting the voltage-stabilizing capacitor C3 can effectively filter out the high-frequency noise, thereby helping to improve the overall electromagnetic compatibility (EMC) and stability of the system.

[0205] Based on the same inventive concept, Figure 8 As shown, the present application further provides a power supply 1000 , which includes a battery pack 200 and an energy storage converter 100 as described in any of the above embodiments of the present application. The battery pack 200 is electrically connected to the energy storage converter 100 .

[0206] For example, the power source is a portable power source, such as a small DC mobile power source or a medium AC / DC mobile power source, etc. There are many types of portable power sources, and different types of portable power sources often have different functions and powers, which can be determined according to their application scenarios and needs.

[0207] According to some embodiments of the present application, Fig. 9 As shown, the battery provided in the embodiment of the present application includes 200 including a connector 50 .

[0208] The connector 50 includes a first terminal P+ and a second terminal P-. The first resonant converter 10 is electrically connected to the first terminal P+ and the second terminal P-, respectively. The first resonant converter 10 is electrically connected to the first terminal P+ and the second terminal P-, respectively. The first terminal P+ is defined as the positive output terminal of the battery pack 200, and the second terminal P- is defined as the negative output terminal of the battery pack 200.

[0209] In some examples, the first resonant converter 10 is electrically connected to the first terminal P+ and the second terminal P- in the connector 50 through a power harness, and the second resonant converter 20 is electrically connected to the first terminal P+ and the second terminal P- in the connector 50 through a power harness.

[0210] More specifically, the first end of the first side of the first resonant converter 10 is electrically connected to the first terminal P+ in the connector 50 through the power harness, and the second end of the first side of the first resonant converter 10 is electrically connected to the second terminal P- in the connector 50 through the power harness. The first end of the first side of the second resonant converter 20 is electrically connected to the first terminal P+ in the connector 50 through the power harness, and the second end of the first side of the second resonant converter 20 is electrically connected to the second terminal P- in the connector 50 through the power harness.

[0211] It should be understood that the power supply 1000 provided in the embodiment of the present application includes the beneficial effects of the energy storage converter 100 provided in the embodiment of the present application. For details, reference may be made to the specific description of the energy storage converter 100 in the above embodiments, which will not be repeated in this embodiment.

[0212] In some examples, the battery pack 200 also includes a battery management system (BMS) and a battery module. The battery management system and the battery module are connected via a power harness and a communication harness. When the battery module is charging and discharging, current flows through the power harness, and the battery management system collects information from the battery module through the signal harness, such as the voltage and temperature of the battery module, the voltage of the battery cells in the battery module, and other information.

[0213] The battery module includes a plurality of battery cells connected in parallel, in series or in hybrid connection for storing and providing electric energy. The battery management system is used to manage and control the charging and discharging process of the battery cell module to improve the utilization efficiency of the battery cell module and reduce failures, etc. The hybrid connection of battery cells refers to the connection of battery cells in series and in parallel. Although the present application has been described with reference to the preferred embodiments, various improvements may be made thereto and components thereof may be replaced by equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An energy storage converter, characterized in that: include: A first resonant converter, wherein a first end of a first side of the first resonant converter is configured to be electrically connected to a first terminal of a battery pack, a second end of the first side of the first resonant converter is configured to be electrically connected to a second terminal of the battery pack, and a first end of a second side of the first resonant converter is electrically connected to a DC bus at a first node; a second resonant converter, wherein a first end of a first side of the second resonant converter is configured to be electrically connected to a first terminal of the battery pack, a second end of the first side of the second resonant converter is configured to be electrically connected to a second terminal of the battery pack, and a second end of a second side of the second resonant converter is electrically connected to the DC bus at a second node; The second end of the second side of the first resonant converter, the first end of the second side of the second resonant converter, and the DC bus are electrically connected to a third node; The first resonant converter and the second resonant converter are configured to balance a first voltage difference and a second voltage difference; The first voltage difference U1 is defined as the voltage difference between the first node and the third node, and the second voltage difference U2 is defined as the voltage difference between the third node and the second node.

2. The energy storage converter according to claim 1, characterized in that: The energy storage converter also includes: A controller is configured to adjust the power of the first resonant converter and / or the power of the second resonant converter according to a difference between the first voltage difference and the second voltage difference, so as to adjust the voltage of the third node.

3. The energy storage converter according to claim 2, characterized in that: The energy storage converter further includes: a first capacitor and a second capacitor disposed on the DC bus; The first capacitor is electrically connected between the first node and the third node, and the second capacitor is electrically connected between the third node and the second node; The first voltage difference is a voltage difference between the two ends of the first capacitor, and the second voltage difference is a voltage difference between the two ends of the second capacitor.

4. The energy storage converter according to claim 3, characterized in that: A capacitance difference between the first capacitance and the second capacitance is less than or equal to a first threshold.

5. The energy storage converter according to any one of claims 2 to 4, characterized in that: The controller is configured to: In response to the battery pack entering or being in a charging state, the difference between the first voltage difference and the second voltage difference is outside a first voltage interval, and the controller controls to increase the charging power of the target resonant converter corresponding to the first target voltage difference; The first target voltage difference is the larger one of the first voltage difference and the second voltage difference, the first resonant converter corresponds to the first voltage difference, and the second resonant converter corresponds to the second voltage difference.

6. The energy storage converter according to any one of claims 2 to 5, characterized in that: The controller is configured to: In response to the battery pack entering or being in a charging state, the difference between the first voltage difference and the second voltage difference is outside a first voltage interval, and the controller controls to reduce the charging power of the target resonant converter corresponding to the second target voltage difference; The second target voltage difference is the smaller one of the first voltage difference and the second voltage difference, the first resonant converter corresponds to the first voltage difference, and the second resonant converter corresponds to the second voltage difference.

7. The energy storage converter according to any one of claims 2 to 6, characterized in that: The controller is configured to: In response to the battery pack entering or being in a charging state, the first voltage difference exceeds the withstand voltage of the first capacitor, and the controller controls to increase the charging power of the first resonant converter and / or reduce the charging power of the second resonant converter; and / or, The controller is also configured to control reducing the charging power of the first resonant converter and / or increasing the charging power of the second resonant converter in response to the battery pack entering or being in a charging state and the second voltage difference exceeding the withstand voltage of the second capacitor.

8. The energy storage converter according to any one of claims 2 to 7, characterized in that: The energy storage converter also includes: a two-phase AC-DC converter; The first end of the first side of the two-phase AC-DC converter is electrically connected to the first node, the second end of the first side of the two-phase AC-DC converter is electrically connected to the second node, the first live wire terminal and the neutral wire terminal of the second side of the two-phase AC-DC converter are configured to be electrically connected to a first load, the second live wire terminal and the neutral wire terminal of the second side of the two-phase AC-DC converter are configured to be electrically connected to a second load, and the neutral wire terminal is electrically connected to the third node; The first live wire terminal and the second live wire terminal of the second side of the two-phase AC-DC converter are also configured to be electrically connected to an AC power source; The controller is configured to: In response to the battery pack entering or being in a charging state, the controller controls the two-phase AC-DC converter to operate in a rectification mode; In response to the battery pack entering or being in a discharging state, the controller controls the two-phase AC-DC converter to operate in an inverter mode.

9. The energy storage converter according to claim 8, characterized in that: The controller is configured to: In response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the second voltage difference is outside a second voltage range, and the controller adjusts the power of the first resonant converter and / or the discharge power of the second resonant converter to adjust the voltage of the third node.

10. The energy storage converter according to claim 9, characterized in that: The controller is configured to: In response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the second voltage difference is outside the second voltage interval, and the controller controls to increase the discharging power of the target resonant converter corresponding to a third target voltage difference; The third target voltage difference is the smaller one of the first voltage difference and the second voltage difference, the first resonant converter corresponds to the first voltage difference, and the second resonant converter corresponds to the second voltage difference.

11. The energy storage converter according to claim 9 or 10, characterized in that: The controller is configured to: In response to the battery pack entering or being in a discharging state, the difference between the first voltage difference and the fourth voltage difference is outside the second voltage interval, and the controller controls to reduce the discharging power of the target resonant converter corresponding to the fourth target voltage difference; The fourth target voltage difference value is a larger one of the first voltage difference value and the second voltage difference value, the first resonant converter corresponds to the first voltage difference value, and the second resonant converter corresponds to the second voltage difference value.

12. The energy storage converter according to claim 8, characterized in that: The controller is configured to: In response to the battery pack entering or being in a discharging state, the difference between the first voltage difference value and the target voltage value exceeds a first voltage threshold, and the controller controls to reduce the discharging power of the first resonant converter; or, In response to the battery pack entering or being in a discharging state, the difference between the first voltage difference value and the target voltage value is less than a second voltage threshold, and the controller increases the discharging power of the first resonant converter. The target voltage value U 目标 The third voltage difference U3 satisfies: 目标 -1 / 2*U3|≤third voltage threshold, the third voltage difference U3 is the voltage difference between the first node and the second node that are expected to be stabilized when the battery pack is discharged.

13. The energy storage converter according to claim 8, characterized in that: The controller is configured to: In response to the battery pack entering or being in a discharging state, the difference between the second voltage difference value and the target voltage value exceeds a fourth voltage threshold, and the controller controls to reduce the discharging power of the second resonant converter; or, In response to the battery pack entering or being in a discharging state, the difference between the second voltage difference value and the target voltage value is less than a fifth voltage threshold, the controller controls to increase the discharging power of the second resonant converter; The target voltage value U 目标 The third voltage difference U3 satisfies: 目标 -1 / 2*U3|≤sixth voltage threshold, the third voltage difference U3 is the voltage difference between the first node and the second node that are expected to be stabilized when the battery pack is discharged.

14. The energy storage converter according to any one of claims 1 to 13, characterized in that: The rated output power of the first resonant converter and the rated output power of the second resonant converter are both less than a second threshold; The range of the second threshold is [3KW, 6KW].

15. The energy storage converter according to any one of claims 1 to 14, characterized in that: The first resonant converter is a bidirectional DC-DC resonant converter; The second resonant converter is a bidirectional DC-DC resonant converter.

16. A power supply, characterized in that: The power source includes a battery pack and an energy storage converter as described in any one of claims 1 to 15, and the battery pack is electrically connected to the energy storage converter.

17. The power supply according to claim 16, characterized in that The battery pack includes a connector; The connector includes a first terminal and a second terminal, the first resonant converter is electrically connected to the first terminal and the second terminal respectively, and the second resonant converter is electrically connected to the first terminal and the second terminal respectively; The first terminal is defined as a positive output terminal of the battery pack, and the second terminal is defined as a negative output terminal of the battery pack.

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