BUCK-BOOST multistage half-bridge circuit series aging topological structure and control method

Abstract

The invention discloses a BUCK-BOOST multi-stage half-bridge circuit series aging topological structure and a control method, and in the topological structure, a front-stage BUCK circuit and a rear-stage BOOST circuit are symmetrically designed by taking a voltage-stabilizing energy-storage capacitor as a center; the pre-stage BUCK circuit comprises a plurality of BUCK half-bridge units which are cascaded in sequence, and the post-stage BOOST circuit comprises a plurality of BOOST half-bridge units which are cascaded in sequence; the BUCK half-bridge unit and the BOOST half-bridge unit have the same circuit structure and each comprise an upper bridge arm and a lower bridge arm; in the BUCK half-bridge unit, an upper bridge arm switch and a lower bridge arm switch are connected to the output end of the upper stage, and an inductor L and the negative end of a lower bridge arm are connected to the input end of the lower stage; in the BOOST half-bridge unit, the inductor L and the negative end of the lower bridge arm are connected to the output end of the upper stage, and the upper bridge arm switch and the lower bridge arm switch are connected to the input end of the lower stage. According to the invention, cascade aging of BUCK and BOOST is realized, the aging efficiency is greatly improved, the energy loss is reduced, the cost is saved, the cascade aging is closer to system operation, the verification is more sufficient, and the working condition coverage is larger.

Description

Technical Field

[0001] The present invention relates to the technical field of aging test of power electronic products, and in particular to a BUCK-BOOST multi-stage half-bridge circuit series aging topology structure and a control method. Background Art

[0002] During the factory testing of power electronic products, product aging testing is a key step in verifying their long-term operational reliability, stability, and safety, and is crucial for ensuring product quality and user safety. Half-bridge circuits, as the core power unit of mainstream topologies such as BUCK and BOOST, are widely used in various power supplies and converter products. The adequacy and effectiveness of their aging testing directly determine the quality of the final product. However, for half-bridge circuits, especially half-bridge power modules used in scenarios requiring high performance and high reliability, the current aging test methods have significant technical limitations, which are mainly manifested in the following aspects:

[0003] 1. Low burn-in efficiency and high power loss: Traditional burn-in methods (such as pure resistive load burn-in) typically use a dissipative load, converting electrical energy into heat and dissipating it. This results in significant power loss and high operating costs. Limited by the power capacity and heat dissipation capabilities of the test equipment, as well as the complexity of the test circuit, existing solutions often struggle to perform simultaneous burn-in of multiple half-bridge devices, resulting in low burn-in test throughput.

[0004] Second, lack of actual operating conditions or dynamic performance verification: Existing aging solutions overly rely on static current flow testing, which mainly verifies the device's conduction characteristics under continuous current. There is a lack of effective simulation and verification of the dynamic operating conditions frequently encountered by half-bridge circuits in actual operation, such as the dynamic performance during PWM switching. These dynamic performance defects are often the main risk points for power device failure in field applications, and existing aging methods are seriously insufficient to verify this.

[0005] 3. Insufficient aging verification for common-mode and interference issues: For half-bridge modules that require cascaded applications, existing aging is typically performed at the single-module level. The single-module aging environment differs significantly from the actual cascaded system operating environment. This makes the aging process inadequate in revealing potential issues that may arise in half-bridge modules under system-level applications, and lacks the ability to predict risks from a system-level perspective.

[0006] 4. Insufficient test coverage and high equipment redundancy: To simulate different load conditions (such as buck step-down and boost step-up), traditional solutions require dedicated test equipment or complex load switching networks for each operating condition. This high level of equipment redundancy, complex wiring, and poor flexibility make it difficult to quickly adapt to the testing requirements of half-bridge modules of different specifications or complex and changing operating conditions, further limiting the coverage of aging verification.

[0007] In summary, there is an urgent need to develop a new half-bridge circuit aging solution to solve the current problems of low aging efficiency of half-bridge cascade modules, large aging energy loss, high aging cost of complex platforms, lack of aging dynamic performance testing, and incomplete coverage of working conditions. Summary of the Invention

[0008] The purpose of the present invention is to provide a BUCK-BOOST multi-stage half-bridge circuit series aging topology and control method, which realizes cascade aging of BUCK and BOOST, greatly improves aging efficiency, reduces energy loss and saves costs. At the same time, the cascade aging can be closer to system operation, with more complete verification and wider operating condition coverage, thus solving the current problems of low aging efficiency, incomplete operating condition verification, and high aging cost.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] A BUCK-BOOST multi-stage half-bridge circuit series aging topology structure includes a front-stage BUCK circuit, a voltage-stabilizing energy storage capacitor, and a rear-stage BOOST circuit. The front-stage BUCK circuit and the rear-stage BOOST circuit are symmetrically designed with the voltage-stabilizing energy storage capacitor as the center.

[0011] The input end of the front-stage BUCK circuit is used to connect to a DC source, and the output end is connected in parallel to both ends of the voltage-stabilizing energy storage capacitor; the front-stage BUCK circuit includes a plurality of BUCK half-bridge units cascaded in sequence;

[0012] The input end of the post-stage BOOST circuit is connected in parallel to both ends of the voltage-stabilizing energy storage capacitor, and the output end is connected to the terminal load; the post-stage BOOST circuit includes a plurality of BOOST half-bridge units cascaded in sequence;

[0013] The BUCK half-bridge unit and the BOOST half-bridge unit have the same circuit structure, both including an upper bridge arm and a lower bridge arm. Both the upper bridge arm and the lower bridge arm include a capacitor C and a half-bridge module connected in parallel to both ends of the capacitor C. The half-bridge module includes two power switches connected in series. In the upper bridge arm, the positive and negative ends of the capacitor C are respectively connected to the upper bridge arm switch, and the midpoint of the half-bridge module is connected to the inductor L. In the lower bridge arm, the positive and negative ends of the capacitor C are respectively connected to the lower bridge arm switch, and the midpoint of the half-bridge module is connected to the negative end of the upper bridge arm. The BUCK half-bridge unit and the BOOST half-bridge unit are symmetrically arranged on both sides of the voltage-stabilizing energy storage capacitor.

[0014] The difference between the BUCK half-bridge unit and the BOOST half-bridge unit is that: in the BUCK half-bridge unit, the upper bridge arm switch and the lower bridge arm switch serve as input terminals for connecting to the output terminal of the previous stage, and the inductor L and the negative end of the lower bridge arm serve as output terminals for connecting to the input terminal of the next stage; in the BOOST half-bridge unit, the inductor L and the negative end of the lower bridge arm serve as input terminals for connecting to the output terminal of the previous stage, and the upper bridge arm switch and the lower bridge arm switch serve as output terminals for connecting to the input terminal of the next stage.

[0015] Furthermore, the power switch is MOSFET, IGBT or silicon carbide MOS.

[0016] Furthermore, the upper arm switch and the lower arm switch are relays.

[0017] Furthermore, in the front-stage buck circuit, the upper bridge arm switch and the lower bridge arm switch at the positive end of the first buck half-bridge unit are arranged from near to far in the direction of proximity to the DC source, and the upper bridge arm switch and the lower bridge arm switch at the negative end are used to connect to the negative end of the DC source; the upper bridge arm switch and the lower bridge arm switch at the positive end of the second buck half-bridge unit are connected to the inductor L of the first buck half-bridge unit, and the upper bridge arm switch and the lower bridge arm switch at the negative end are connected to the negative end of the lower bridge arm of the first buck half-bridge unit; and so on, the upper bridge arm switch and the lower bridge arm switch at the positive end of the last buck half-bridge unit are connected to the inductor L of the previous buck half-bridge unit, and the upper bridge arm switch and the lower bridge arm switch at the negative end are connected to the negative end of the lower bridge arm of the previous buck half-bridge unit;

[0018] The inductor L of the last BUCK half-bridge unit and the negative end of the lower bridge arm are connected in parallel to both ends of the voltage-stabilizing energy storage capacitor.

[0019] Furthermore, in the latter stage BOOST circuit, the inductor L of the first BOOST half-bridge unit and the negative end of the lower bridge arm are connected in parallel to the two ends of the voltage-stabilizing energy storage capacitor in the direction of proximity to the voltage-stabilizing energy storage capacitor; the inductor L of the second BOOST half-bridge unit is connected to the upper bridge arm switch and the lower bridge arm switch at the positive end of the first BOOST half-bridge unit, and the negative end of the lower bridge arm is connected to the upper bridge arm switch and the lower bridge arm switch at the negative end of the first BOOST half-bridge unit; and so on, the inductor L of the last BOOST half-bridge unit is connected to the upper bridge arm switch and the lower bridge arm switch at the positive end of the previous BOOST half-bridge unit, and the negative end of the lower bridge arm is connected to the upper bridge arm switch and the lower bridge arm switch at the negative end of the previous BOOST half-bridge unit;

[0020] The upper bridge arm switch and the lower bridge arm switch at the positive end of the last BOOST half-bridge unit are connected to one end of the end load, and the upper bridge arm switch and the lower bridge arm switch at the negative end are connected to the other end of the end load.

[0021] Furthermore, the terminal load is an energy-consuming load or a grid-feeding load.

[0022] Furthermore, the number of cascaded BUCK half-bridge units is the same as the number of cascaded BOOST half-bridge units, and both are greater than or equal to 2.

[0023] The present invention further provides a control method for a BUCK-BOOST multi-stage half-bridge circuit series aging topology structure, which is applied to the above-mentioned BUCK-BOOST multi-stage half-bridge circuit series aging topology structure, comprising:

[0024] Connect to a DC source;

[0025] Upper arm aging mode: Close all upper arm switches, open all lower arm switches, and perform circulation aging on all upper arm half-bridge modules. All upper arm half-bridge modules are in PWM mode.

[0026] Lower arm aging mode: Close all lower arm switches, open all upper arm switches, and perform flow aging on all lower arm half-bridge modules. All lower arm half-bridge modules are in PWM mode.

[0027] Furthermore, all upper arm switches and lower arm switches use relays and are electrically connected to the controller to achieve remote on-off control; the controller is also connected to each power switch to control the PWM signal.

[0028] Furthermore, it also includes:

[0029] When powered on, first turn on the control power, set the wave logic of each half-bridge module through the controller and start the wave, then turn on the power power, connect the DC source, set the source voltage and output it, close the corresponding switch according to the aging mode, and perform aging;

[0030] When power is turned off, the power supply is first turned off, the DC source is removed, and after a first delay, all half-bridge modules are blocked from sending wave instructions. After a second delay, the closed switches in the aging mode are opened. After a third delay, the control power is turned off.

[0031] When switching between different aging modes, after the previous aging mode ends, the fourth time period is delayed, and then the switch corresponding to the next aging mode is closed, and the DC source is turned on to start aging.

[0032] According to the specific embodiments provided by the present invention, the BUCK-BOOST multi-stage half-bridge circuit series aging topology structure and control method provided by the present invention disclose the following technical effects:

[0033] (1) Significantly improve the scalability and flexibility of cascade aging: Based on the BUCK circuit, the BOOST circuit is introduced to realize the boost mode cascade, which effectively overcomes the limitations of the pure BUCK cascade caused by the step-by-step reduction of input voltage and power level; any number of half-bridge modules can be cascaded for aging, and the single-batch aging capacity is greatly improved, breaking through the limitation of the number of traditional series connections.

[0034] (2) Achieve aging verification in the full range of operating conditions: With the voltage-stabilizing energy storage capacitor in the middle as the symmetrical center, half of the modules work in the BUCK step-down mode, and the other half work in the BOOST step-up mode. This can simultaneously verify the performance and reliability of the half-bridge topology in both the buck and boost working modes, covering its full range of operating conditions. The coupled operation of multiple modules and multiple working modes can more effectively verify the system-level reliability and interactive stability of the cascaded product as a whole.

[0035] (3) Improve energy utilization efficiency and reduce costs: The terminal load can be selected as energy consumption type or grid feeding type (energy feedback to the grid). The grid feeding type load can recycle most of the energy consumed during the aging process, greatly reducing the energy consumption cost of the aging test.

[0036] (4) Improve operational convenience and automation: A multi-level switch network is used to automatically switch on and off the aging bridge arm by controlling different switches, avoiding the tedious operation of repeated manual wiring in traditional solutions, reducing operational difficulty and error risks, and improving efficiency.

[0037] (5) Enhanced equipment safety and reliability: The control method innovatively adopts the "priority wave control" strategy, which controls the opening of the internal switch of the module before connection, so that the capacitor voltage inside the module rises slowly following the DC source voltage (soft start), effectively avoiding the surge current generated when the capacitor is directly connected in series, protecting the module from damage, and eliminating the need for an additional soft start circuit.

[0038] (6) Wide range of topology adaptability and scalability: This cascade aging solution is not only applicable to cascade half-bridge (H-Bridge), but also to series cascade aging scenarios such as cascade full-bridge (Full-Bridge) rectification and inverter. The solution is flexible in design and can be expanded and applied according to the specific needs of different power converter topologies (such as rectifiers and inverters).

[0039] (7) Supporting preliminary system-level verification: Through multi-bridge arm cascade aging, system-level interaction problems such as common-mode coupling that may exist when multiple modules are cascaded can be preliminarily verified before product-level testing, providing earlier reliability feedback for the final system integration.

[0040] In summary, the present invention uses BUCK and BOOST cascade for aging, aiming to increase the number of aging units in a single batch, reduce energy loss, improve aging efficiency, reduce labor costs, adapt to more working conditions, and improve product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 Schematic diagram of the aging topology structure of the BUCK multi-stage half-bridge circuit in series in Example 1 of the present invention;

[0043] Figure 2 Schematic diagram of the series aging topology of the BUCK-BOOST multi-stage half-bridge circuit in Example 2 of the present invention, wherein (a) is the front-stage BUCK circuit with the voltage-stabilizing energy storage capacitor as the dividing line, and (b) is the rear-stage BOOST circuit with the voltage-stabilizing energy storage capacitor as the dividing line;

[0044] Figure 3 Schematic diagram of the current loop of the BUCK-BOOST multi-stage half-bridge circuit series aging topology in Example 2 of the present invention, wherein (a) is the front-stage BUCK circuit with the voltage-stabilizing energy storage capacitor as the dividing line, and (b) is the rear-stage BOOST circuit with the voltage-stabilizing energy storage capacitor as the dividing line;

[0045] Figure 4 This is a flow chart of a control method for a BUCK-BOOST multi-stage half-bridge circuit series aging topology structure in Example 2 of the present invention;

[0046] Figure 5 This is a prior art through-aging circuit for power tubes;

[0047] Figure 6 This is the second existing technology for the aging solution of a single device. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] The purpose of the present invention is to provide a BUCK-BOOST multi-stage half-bridge circuit series aging topology and control method to solve the problems of high cost, low aging efficiency and incomplete working condition verification encountered in current half-bridge aging.

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] like Figure 1 As shown, the BUCK multi-stage half-bridge circuit series aging topology structure provided by Example 1 of the present invention has an input end connected to a DC source and an output end connected to a terminal load; it includes a plurality of BUCK half-bridge units cascaded in sequence;

[0053] The BUCK half-bridge unit includes an upper bridge arm and a lower bridge arm, and each of the upper bridge arm and the lower bridge arm includes a capacitor C( Figure 1 and Figure 2 C1-C16 in the figure) and a half-bridge module connected in parallel at both ends of the capacitor C, wherein the half-bridge module includes two power switches (such as MOS tubes, Figure 1 and Figure 2 Q1-Q32 in the upper bridge arm); in the upper bridge arm, the positive end and the negative end of the capacitor C are connected to the upper bridge arm switch, and the midpoint of the half bridge of the half bridge module is connected to the inductor L ( Figure 1 and Figure 2 L1-L8 in the lower bridge arm); in the lower bridge arm, the positive end and the negative end of the capacitor C are respectively connected to the lower bridge arm switch, and the midpoint of the half bridge of the half bridge module is connected to the negative end of the upper bridge arm; the BUCK half bridge unit and the BOOST half bridge unit are symmetrically arranged on both sides of the voltage stabilizing energy storage capacitor;

[0054] In the BUCK half-bridge unit, the upper arm switch and the lower arm switch serve as input terminals for connecting to the output terminal of the previous stage, and the inductor L and the negative end of the lower arm serve as output terminals for connecting to the input terminal of the next stage.

[0055] The upper bridge arm is connected to a battery module through BAT1+ and BAT1-, and the lower bridge arm is connected to another battery module through BAT2+ and BAT2-. Battery modules with different aging are switched respectively by controlling the upper and lower bridge arm switches.

[0056] The topology provided in this embodiment 1 adopts a 4-stage series aging method. Specifically, it works in the BUCK mode. The input voltage (input DC source) is remotely controlled to cut off different switches to confirm the aging direction and aging half-bridge. For example, the aging direction is uniformly closed. Figure 1 The lower bridge arm switch (K dn1 —K dn8), the half-bridge module in the lower bridge arm will be aged, and the power switches in the four groups of half-bridge modules will be in PWM operation mode (that is, the upper and lower MOS tubes of the lower bridge arm are turned on respectively and enter the chopping mode) to verify the dynamic performance parameters.

[0057] closure Figure 1 The upper arm switch (K up1 —K up8 ), then switch the aging circuit to age the upper bridge arm. It only needs to control the corresponding switch without involving wiring. At the same time, aging multiple half-bridge modules only requires one DC source. At the same time, the load end resistor can also be replaced with a grid-fed load to reduce loss and save costs.

[0058] However, Example 1 solely adopts a BUCK cascade aging solution. Since each stage adopts the BUCK-PWM chopping step-down mode, the voltage of the subsequent stage will continue to decrease, and the number of series connections will be limited, which cannot correspond to actual working conditions. Therefore, the present invention further improves and proposes a BUCK-BOOST multi-stage half-bridge circuit series aging topology as described in Example 2.

[0059] Example 2

[0060] like Figure 2-Figure 3 As shown, the BUCK-BOOST multi-stage half-bridge circuit series aging topology provided by Example 2 of the present invention includes a front-stage BUCK circuit, a voltage-stabilizing energy storage capacitor C_s, and a rear-stage BOOST circuit. The front-stage BUCK circuit and the rear-stage BOOST circuit are symmetrically designed with the voltage-stabilizing energy storage capacitor as the center;

[0061] like Figure 2 As shown in (a), the input end of the front-stage BUCK circuit is used to connect to a DC source, and the output end is connected in parallel to both ends of the voltage-stabilizing energy storage capacitor C_s; the front-stage BUCK circuit includes a plurality of BUCK half-bridge units cascaded in sequence;

[0062] like Figure 2 As shown in (b), the input end of the post-stage BOOST circuit is connected in parallel to the two ends of the voltage-stabilizing energy storage capacitor C_s, and the output end is connected to the end load R_load; the post-stage BOOST circuit includes a plurality of BOOST half-bridge units cascaded in sequence;

[0063] The BUCK half-bridge unit and the BOOST half-bridge unit have the same circuit structure, both including an upper bridge arm and a lower bridge arm. Both the upper bridge arm and the lower bridge arm include a capacitor C and a half-bridge module connected in parallel to both ends of the capacitor C. The half-bridge module includes two power switches connected in series. In the upper bridge arm, the positive and negative ends of the capacitor C are respectively connected to the upper bridge arm switch, and the midpoint of the half-bridge module is connected to the inductor L. In the lower bridge arm, the positive and negative ends of the capacitor C are respectively connected to the lower bridge arm switch, and the midpoint of the half-bridge module is connected to the negative end of the upper bridge arm. The BUCK half-bridge unit and the BOOST half-bridge unit are symmetrically arranged on both sides of the voltage-stabilizing energy storage capacitor.

[0064] The difference between the BUCK half-bridge unit and the BOOST half-bridge unit is that: in the BUCK half-bridge unit, the upper bridge arm switch and the lower bridge arm switch serve as input terminals for connecting to the output terminal of the previous stage, and the inductor L and the negative end of the lower bridge arm serve as output terminals for connecting to the input terminal of the next stage; in the BOOST half-bridge unit, the inductor L and the negative end of the lower bridge arm serve as input terminals for connecting to the output terminal of the previous stage, and the upper bridge arm switch and the lower bridge arm switch serve as output terminals for connecting to the input terminal of the next stage.

[0065] For example, the power switch may be a MOSFET, an IGBT, or a silicon carbide MOS. A MOSFET is specifically used in Embodiment 2 of the present invention. The upper arm switch and the lower arm switch are relays, which connect and disconnect contacts by controlling the on and off of the coil.

[0066] Specifically, in the front-stage buck circuit, the upper bridge arm switch and the lower bridge arm switch at the positive end of the first buck half-bridge unit are arranged from near to far in the direction of proximity to the DC source, and the upper bridge arm switch and the lower bridge arm switch at the negative end are used to connect to the negative end of the DC source; the upper bridge arm switch and the lower bridge arm switch at the positive end of the second buck half-bridge unit are connected to the inductor L of the first buck half-bridge unit, and the upper bridge arm switch and the lower bridge arm switch at the negative end are connected to the negative end of the lower bridge arm of the first buck half-bridge unit; and so on, the upper bridge arm switch and the lower bridge arm switch at the positive end of the last buck half-bridge unit are connected to the inductor L of the previous buck half-bridge unit, and the upper bridge arm switch and the lower bridge arm switch at the negative end are connected to the negative end of the lower bridge arm of the previous buck half-bridge unit;

[0067] The inductor L of the last BUCK half-bridge unit and the negative end of the lower bridge arm are connected in parallel to both ends of the voltage-stabilizing energy storage capacitor.

[0068] The positive end of the buck half-bridge unit includes the positive ends of the upper and lower half-bridge modules, and the negative end of the buck half-bridge unit includes the negative ends of the upper and lower half-bridge modules. The positive and negative ends of the half-bridge module in the upper arm are respectively connected to an upper arm switch, and the positive and negative ends of the half-bridge module in the lower arm are respectively connected to a lower arm switch.

[0069] In the latter stage BOOST circuit, the inductors L and the negative end of the lower bridge arm of the first BOOST half-bridge unit are arranged in order from near to far in the direction close to the voltage-stabilizing energy storage capacitor, and are connected in parallel to both ends of the voltage-stabilizing energy storage capacitor; the inductor L of the second BOOST half-bridge unit is connected to the upper bridge arm switch and the lower bridge arm switch at the positive end of the first BOOST half-bridge unit, and the negative end of the lower bridge arm is connected to the upper bridge arm switch and the lower bridge arm switch at the negative end of the first BOOST half-bridge unit; and so on, the inductor L of the last BOOST half-bridge unit is connected to the upper bridge arm switch and the lower bridge arm switch at the positive end of the previous BOOST half-bridge unit, and the negative end of the lower bridge arm is connected to the upper bridge arm switch and the lower bridge arm switch at the negative end of the previous BOOST half-bridge unit;

[0070] The upper bridge arm switch and the lower bridge arm switch at the positive end of the last BOOST half-bridge unit are connected to one end of the end load, and the upper bridge arm switch and the lower bridge arm switch at the negative end are connected to the other end of the end load.

[0071] Among them, the positive end of the BOOST half-bridge unit includes the positive end of the upper and lower half-bridge modules, the negative end of the BOOST half-bridge unit includes the negative end of the upper and lower half-bridge modules, the positive end and negative end of the half-bridge module in the upper bridge arm are respectively connected to an upper bridge arm switch, and the positive end and negative end of the half-bridge module in the lower bridge arm are respectively connected to a lower bridge arm switch.

[0072] For example, the terminal load is an energy-consuming load or a grid-fed load, preferably a grid-fed load, to reduce losses and save costs.

[0073] In the second embodiment, the number of cascaded BUCK half-bridge units is the same as the number of cascaded BOOST half-bridge units, both of which are 4.

[0074] like Figure 2 As shown, when the upper bridge arm is aging, only the upper bridge arm switch marked in black needs to be closed (including K Boost_up and K Buck_up) , at this time, the current path will flow through the upper bridge arm to age. Among them, BUCK half-bridge unit #1-BUCK half-bridge unit #4 is a half-bridge in BUCK mode; BOOST half-bridge unit #5-BOOST half-bridge unit #8 is a half-bridge in BOOST mode. If you need to switch the aged lower bridge arm, you need to open the upper bridge arm switch and close the lower bridge arm switch (including K Boost_dn and K Buck_dn ) is enough, at this time the current path will flow through the following bridge arms for aging. Figure 2As shown in the figure, the buck and boost circuit structures are designed symmetrically with the voltage-stabilizing energy storage capacitor as the center. This connection minimizes component usage. The chopped output of the first four buck half-bridge units (i.e., the output port of buck half-bridge unit #4) is filtered by inductors and capacitors and serves as the input of the subsequent boost circuit, entering boost mode. This symmetrical approach only requires the addition of a voltage-stabilizing energy storage capacitor in the center. If other approaches are used, such as staggered buck and boost circuits, additional capacitors are required at each stage for energy storage and voltage regulation. The voltage-stabilizing energy storage capacitor between buck half-bridge unit #4 and boost half-bridge unit #5 is essential for the buck and boost cascade. As a voltage-stabilizing energy storage device, this capacitor provides a stable DC input voltage for boost half-bridge unit #5, enabling the subsequent boost and buck cascade.

[0075] like Figure 3 As shown in the figure, a schematic diagram of the power flow of some half-bridge modules in the BUCK-BOOST multi-stage half-bridge circuit series aging topology is shown. In the front-stage BUCK circuit, the current output loop of unit #1 is as follows: Figure 3 As shown in the middle blue circuit: the current starts from the capacitor of unit #1, passes through the power tube and inductor, charges the capacitor of unit #2, and then returns to the capacitor of unit #1 through the circuit (only the output circuit is shown here, and the freewheeling circuit is not shown). The capacitor of unit #2 is equivalent to the load of unit #1; the green and blue circuits are cascade circuits, unit #1 outputs current to unit #2, and unit #2 continues to output current to unit #3. The cascade connection is successive, and the subsequent unit acts as the load of the previous unit. The chopped output of the previous unit charges the capacitor of the subsequent unit, and so on (the blue, green, and yellow current paths are the output circuits in buck mode).

[0076] The same applies to the BOOST mode. Here we only show the output current loop of unit #5 and unit #8 (the energy storage freewheeling loop is not shown). Figure 3 As shown in the figure, in the post-stage boost circuit, the dark blue diagram shows the output current of unit #5. The current is input into the voltage-stabilizing energy storage capacitor via unit #4, then PWM-modulated by the power transistor in unit #5, and then output to the capacitor in unit #5 for storage. Unit #5 then cascades the output to unit #6, and so on, ultimately dissipating the energy through a resistive load (or other type of load) in unit #8, completing the entire unit cascade aging process. If common-mode interference exists at each stage, it will cascade progressively, increasing the interference. This comparison further verifies product reliability.

[0077] In summary, the BUCK-BOOST multi-stage half-bridge circuit series aging topology provided in Example 2 of the present invention, compared with Example 1, expands the BOOST boost mode cascade, which can overcome the power level drop and input voltage insufficient problems caused by multi-stage series connection; at the same time, the BOOST and BUCK aging modes are verified, such as Figure 2 As shown, with the center capacitor as the symmetric element, cells #1-#4 operate in BUCK mode, and cells #5-#8 operate in BOOST mode, enabling full coverage and verification of the half-bridge's operating range. Once voltage and power flow drop issues are resolved, the number of half-bridges that can be cascaded for burn-in is unlimited and can be increased (depending on the designer's needs). Multi-cascade burn-in modes, coupled with various operating modes, further validate the overall reliability of the cascaded product. For end loads, which can be either energy-consuming or grid-feeding, this further reduces energy loss and saves costs.

[0078] In addition, if Figure 4 As shown, the present invention also provides a control method for a BUCK-BOOST multi-stage half-bridge circuit series aging topology structure, which is applied to the above-mentioned BUCK-BOOST multi-stage half-bridge circuit series aging topology structure, comprising:

[0079] Connect to a DC source;

[0080] Upper arm aging mode: Close all upper arm switches, open all lower arm switches, and perform circulation aging on all upper arm half-bridge modules. All upper arm half-bridge modules are in PWM mode.

[0081] Lower arm aging mode: Close all lower arm switches, open all upper arm switches, and perform flow aging on all lower arm half-bridge modules. All lower arm half-bridge modules are in PWM mode.

[0082] Among them, all upper arm switches and lower arm switches use relays and are electrically connected to a controller (such as a cluster controller of a battery module) to achieve remote on / off control; the controller is also connected to each power switch to control the PWM signal.

[0083] Specifically, the control method includes cascaded BUCK-BOOST half-bridge aging control and operation mode;

[0084] First, confirm the aging of the upper and lower bridge arms through the switch control. By default, after the installation is completed, the aging method is to first aging the upper bridge arm and then the lower bridge arm.

[0085] Upper / lower bridge arm aging:

[0086] 1) Place the half-bridge module in the designated location and connect the pipes and terminals as required;

[0087] 2) First turn on the control power to ensure that the single module control board and relays are working properly, and the relay switch is switched to the upper bridge arm (such as Figure 2 The upper bridge arm switch is closed);

[0088] 3) After a delay of 10 seconds, the controller issues a wave-generating instruction to each bridge arm of the cascaded half-bridge to perform wave-generating operation;

[0089] 4) After a delay of 10 seconds, the controller controls the DC source measurement relay to switch to the upper bridge arm aging switch. After a delay of 10 seconds, the DC source is turned on to set parameters and power on for aging.

[0090] 5) After the aging is completed after 40 minutes, the controller sends a command to remotely shut down the DC source first, and then issues a command to block the aging of the upper bridge arm 1 minute later. After 10 seconds, it issues a command to cut off the aging relay of the upper bridge arm;

[0091] 6) After 10 seconds, the controller issues a command to switch the module relay to the lower bridge arm;

[0092] 7) After 10 seconds, the controller issues the lower bridge arm aging wave instruction;

[0093] 8) After 10 seconds, the controller controls the source side relay to switch to the lower bridge arm aging switch;

[0094] 9) After 10 seconds, remotely set the DC source parameters and turn on the DC source to perform lower arm aging.

[0095] 10) After the aging is completed after 40 minutes, the DC source is remotely shut down first. One minute later, the controller issues a lower bridge arm aging wave blocking instruction. After 10 seconds, the lower bridge arm aging relay switch is disconnected.

[0096] 11) Power off the control side and manually shut down the liquid cooling unit to drain the liquid after 1 minute;

[0097] 12) Remove the module for the next batch of aging.

[0098] As mentioned above: in the above aging steps, the controller is used to uniformly issue instructions for the switching of the bridge arm switches and the wave generation of the module control board. This comprehensive control method is more efficient and safer than individually controlling the relays and single-board wave generation instructions. For example, if the relays are individually controlled, there is a possibility of mis-issuance, or some relay switching instructions may not be issued. At this time, there will be safety issues in disassembling the module. The controller issues instructions uniformly. It only needs to ensure that the line connection is normal, and then issue them according to the collective instructions, and return the instructions to verify whether they are completely issued. This can make the operation steps more safe and reliable, and the control efficiency is higher.

[0099] The existence of delay is mainly based on the RC discharge and safety perspectives. It takes the approach of first controlling the DC source to power off, and then issuing the wave blocking instruction to ensure that the energy stored in the module is consumed in time and that there are no safety issues when personnel disassemble. The delay control power is finally turned off mainly to check whether the instruction is issued successfully in each step. After ensuring that the entire aging step instruction is executed, the power is turned off and then disassembly is performed, which is safer and more reliable and reduces damage to personnel and equipment.

[0100] Comparative analysis with existing technologies:

[0101] 1. Comparison of device parameters on the aging platform:

[0102] like Figure 5 and Figure 6 As shown: Traditional aging mode is mainly divided into two types. Figure 5 To perform through aging on the power tube (the circuit here only shows the aging mode, and the aging quantity is not used as a reference), such as Figure 5 For the yellow and green circuits, only the upper transistors of the upper and lower bridge arms are directly aged during each aging process. This makes it impossible to perform aging tests under extreme operating conditions such as PWM. The operating condition coverage is low, and system-level interference cannot be tested in advance, resulting in incomplete equipment aging. From a usage perspective, this design only uses N (the number of cascaded modules) fewer reactors and 2N fewer relays than the newly designed aging solution.

[0103] Figure 6 The illustrated burn-in solution is for a single module. While single burn-in for the same number of modules can reduce the number of relay switches by 4, it requires an increase in the number of DC sources and load cabinets by (N-1), resulting in higher overall costs. Furthermore, using resistive loads for single-module burn-in results in further energy loss, increasing electricity costs. Furthermore, the functional performance of the solution does not preemptively verify the risk of cascading interference. While the operating condition coverage is improved on the left, it still has significant shortcomings compared to the new invention solution.

[0104] The BUCK-BOOST cascade aging solution provided by this invention can be expanded to a larger number of units. Considering installation costs, etc., the current batch aging is tentatively scheduled for 8 units. The aging power level remains unchanged. In this case, the DC source parameters must be consistent with the traditional method, and the load box is also consistent with the traditional method. However, 4*7=28 relay switches and 1*7=7 inductors are required. One water-cooling unit is still used, and only a few pipelines need to be added (which can be ignored). If a resistive load is used for the cascade aging of 8 units, the loss and electricity cost are basically the same as for a single unit (only the efficiency difference is negligible).

[0105] Based on the above analysis, relays and inductors are relatively inexpensive compared to DC sources and electricity costs, have fixed parameters, and are highly reliable and reusable. If the number of aging loads is consistent, multiple DC sources and loads can be omitted, reducing power loss and electricity costs. Furthermore, they cover a wider range of operating conditions, identify risks in advance, and increase reliability.

[0106] 2. Comparison from the perspective of labor cost:

[0107] If the traditional aging device removes the remote relay, manual closing is required and there is a risk of errors. In addition, if there is no relay, manual wiring and adjustment are required, which increases labor costs. The relay can be directly inserted in the form of a card position to avoid direct wiring. Only electrical connection at the terminal is required.

[0108] 3. Comparison of functional completeness and reliability

[0109] If a single module is used for aging, only the module itself can be verified. It is impossible to ensure the impact of common-mode coupling interference on the overall reliability of the system when the cascade system is running in multi-module PWM mode. Cascade series aging is used, and common-mode coupling between each other is closer to the entire cascade system than a single module, so it can be verified in advance, further reducing risks and improving reliability.

[0110] Therefore, in summary, the present invention solves the high cost, low efficiency, large loss and poor working condition coverage of single-module half-bridge aging, while effectively controlling the cost and greatly increasing the number of single-batch aging, which has great advantages in practicality.

[0111] Based on the above analysis, the present invention solves the contradiction between cost and balanced efficiency and operating condition coverage encountered in traditional half-bridge aging solutions. On the basis of the original cost device structure, by adding some low-cost devices such as relays and inductors, the aging efficiency is greatly improved, energy loss is reduced, and costs are saved. At the same time, the cascade aging can be closer to the system operation, the verification is more complete, and the operating condition coverage is greater.

[0112] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A BUCK-BOOST multi-stage half-bridge circuit series aging topology structure, characterized in that: It includes the front-stage BUCK circuit, the voltage-stabilizing energy storage capacitor and the rear-stage BOOST circuit. The front-stage BUCK circuit and the rear-stage BOOST circuit are symmetrically designed with the voltage-stabilizing energy storage capacitor as the center. The input end of the front-stage BUCK circuit is used to connect to a DC source, and the output end is connected in parallel to both ends of the voltage-stabilizing energy storage capacitor; the front-stage BUCK circuit includes a plurality of BUCK half-bridge units cascaded in sequence; The input end of the post-stage BOOST circuit is connected in parallel to both ends of the voltage-stabilizing energy storage capacitor, and the output end is connected to the terminal load; the post-stage BOOST circuit includes a plurality of BOOST half-bridge units cascaded in sequence; The BUCK half-bridge unit and the BOOST half-bridge unit have the same circuit structure, both including an upper bridge arm and a lower bridge arm. Both the upper bridge arm and the lower bridge arm include a capacitor C and a half-bridge module connected in parallel to both ends of the capacitor C. The half-bridge module includes two power switches connected in series. In the upper bridge arm, the positive and negative ends of the capacitor C are respectively connected to the upper bridge arm switch, and the midpoint of the half-bridge module is connected to the inductor L. In the lower bridge arm, the positive and negative ends of the capacitor C are respectively connected to the lower bridge arm switch, and the midpoint of the half-bridge module is connected to the negative end of the upper bridge arm. The BUCK half-bridge unit and the BOOST half-bridge unit are symmetrically arranged on both sides of the voltage-stabilizing energy storage capacitor. The difference between the BUCK half-bridge unit and the BOOST half-bridge unit is that: in the BUCK half-bridge unit, the upper bridge arm switch and the lower bridge arm switch serve as input terminals for connecting to the output terminal of the previous stage, and the inductor L and the negative end of the lower bridge arm serve as output terminals for connecting to the input terminal of the next stage; in the BOOST half-bridge unit, the inductor L and the negative end of the lower bridge arm serve as input terminals for connecting to the output terminal of the previous stage, and the upper bridge arm switch and the lower bridge arm switch serve as output terminals for connecting to the input terminal of the next stage.

2. The BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 1, characterized in that: The power switch is MOSFET, IGBT or silicon carbide MOS.

3. The BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 1, characterized in that: The upper bridge arm switch and the lower bridge arm switch are relays.

4. The BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 1, characterized in that: In the front-stage buck circuit, the upper and lower bridge arm switches at the positive end of the first buck half-bridge unit are arranged from near to far in the direction of proximity to the DC source, and the upper and lower bridge arm switches at the negative end are used to connect to the negative end of the DC source; the upper and lower bridge arm switches at the positive end of the second buck half-bridge unit are connected to the inductor L of the first buck half-bridge unit, and the upper and lower bridge arm switches at the negative end are connected to the negative end of the lower bridge arm of the first buck half-bridge unit; and so on, the upper and lower bridge arm switches at the positive end of the last buck half-bridge unit are connected to the inductor L of the previous buck half-bridge unit, and the upper and lower bridge arm switches at the negative end are connected to the negative end of the lower bridge arm of the previous buck half-bridge unit; The inductor L of the last BUCK half-bridge unit and the negative end of the lower bridge arm are connected in parallel to both ends of the voltage-stabilizing energy storage capacitor.

5. The BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 1, characterized in that: In the latter stage BOOST circuit, the inductors L and the negative end of the lower bridge arm of the first BOOST half-bridge unit are arranged in order from near to far in the direction close to the voltage-stabilizing energy storage capacitor, and are connected in parallel to both ends of the voltage-stabilizing energy storage capacitor; the inductor L of the second BOOST half-bridge unit is connected to the upper bridge arm switch and the lower bridge arm switch at the positive end of the first BOOST half-bridge unit, and the negative end of the lower bridge arm is connected to the upper bridge arm switch and the lower bridge arm switch at the negative end of the first BOOST half-bridge unit; and so on, the inductor L of the last BOOST half-bridge unit is connected to the upper bridge arm switch and the lower bridge arm switch at the positive end of the previous BOOST half-bridge unit, and the negative end of the lower bridge arm is connected to the upper bridge arm switch and the lower bridge arm switch at the negative end of the previous BOOST half-bridge unit; The upper bridge arm switch and the lower bridge arm switch at the positive end of the last BOOST half-bridge unit are connected to one end of the end load, and the upper bridge arm switch and the lower bridge arm switch at the negative end are connected to the other end of the end load.

6. The BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 1, characterized in that: The terminal load is an energy-consuming load or a grid-feeding load.

7. The BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 1, characterized in that: The number of cascaded BUCK half-bridge units is the same as the number of cascaded BOOST half-bridge units, and both are greater than or equal to 2.

8. A control method for a BUCK-BOOST multi-stage half-bridge circuit series aging topology structure, applied to the BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to any one of claims 1 to 7, characterized in that: include: Connect to a DC source; Upper arm aging mode: Close all upper arm switches, open all lower arm switches, and perform circulation aging on all upper arm half-bridge modules. All upper arm half-bridge modules are in PWM mode. Lower arm aging mode: Close all lower arm switches, open all upper arm switches, and perform flow aging on all lower arm half-bridge modules. All lower arm half-bridge modules are in PWM mode.

9. The control method for the BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 8, characterized in that: All upper and lower bridge arm switches use relays and are electrically connected to the controller to achieve remote on / off control; the controller is also connected to each power switch to control the PWM signal.

10. The control method for the BUCK-BOOST multi-stage half-bridge circuit series aging topology structure according to claim 9, characterized in that: Also includes: When powered on, first turn on the control power, set the wave logic of each half-bridge module through the controller and start the wave, then turn on the power power, connect the DC source, set the source voltage and output it, close the corresponding switch according to the aging mode, and perform aging; When power is turned off, the power supply is first turned off, the DC source is removed, and after a first delay, all half-bridge modules are blocked from sending wave instructions. After a second delay, the closed switches in the aging mode are opened. After a third delay, the control power is turned off. When switching between different aging modes, after the previous aging mode ends, the fourth time period is delayed, and then the switch corresponding to the next aging mode is closed, and the DC source is turned on to start aging.

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