Flywheel energy storage power module directly connected in parallel with igbt module

Abstract

The application discloses a flywheel energy storage power module directly connected in parallel with IGBT modules, which comprises a support frame, a switching power supply, a control panel, a voltage sensor, a current sensor, a first laminated busbar, a second laminated busbar, a support capacitor, an absorption capacitor, a water-cooled radiator, an IGBT module and an alternating-current output side copper bar, which are all arranged in the support frame. The application greatly improves the parameter consistency of parallel branches through the internal balanced and symmetrical heat dissipation design and the full symmetrical layout of the IGBT module, the laminated busbar and the alternating-current output side copper bar, so that a very high transient and steady-state current sharing coefficient is realized, and the transient and steady-state current sharing coefficients of all parallel devices are all above 0.97 in actual measurement.

Description

Technical Field

[0001] This application relates to the field of electronic power technology, and in particular to a flywheel energy storage power module with IGBT modules directly connected in parallel. Background Technology

[0002] Flywheel energy storage devices are high-power-density energy storage devices with power outputs reaching several megawatts. Existing single IGBT modules struggle to provide sufficient current and voltage to meet these high-power demands. Limited by the current-carrying capacity of a single IGBT module, adopting a multi-parallel IGBT architecture becomes an inevitable choice to break through the megawatt-level power barrier.

[0003] The most important electrical parameter of IGBT parallel technology is the current sharing coefficient. The current sharing coefficient refers to the ratio of the average current of each branch to the maximum current of the power branch in parallel operation. It is used to measure the uniformity of current distribution, and its ideal value is 1. To achieve a high current sharing coefficient, the currently common and consensus-based technical solutions need to consider the following points: (1) Use the same type of IGBT device in the parallel circuit, or ensure that the internal impedance parameters of the device are as consistent as possible; (2) Use uniform and symmetrical cooling equipment to ensure that the junction temperature of each IGBT device is similar; (3) Make the parasitic resistance and parasitic inductance of the power circuit symmetrical. Symmetrical design of the electrical circuit can greatly improve the parameter consistency of each branch, ensure the same line path length, and ensure the same impedance parameters; (4) Use the same driving unit and design the gate driving circuit symmetrically. The biggest difference between the current technical solutions is the implementation of the above points (3) and (4). These two points need to be achieved through structural design, and they are also the two most difficult points. The electrical circuit layout in the existing technical solution is difficult to provide a sufficiently small and uniform circuit impedance, resulting in a low current sharing coefficient in each branch of the parallel circuit. Although the total current at the parallel terminal can meet the load requirements, the uneven current in each branch causes inconsistent losses and junction temperatures of each power device, which can even be very different. Devices that carry large currents suffer higher losses and switching overvoltages, thus these devices bear a high risk of damage and reduced reliability. Application content

[0004] The purpose of this invention is to provide a flywheel energy storage power module with IGBT modules directly connected in parallel, thereby solving the problems mentioned in the background art.

[0005] A flywheel energy storage power module with IGBT modules directly connected in parallel includes a support frame, a switching power supply, a control board, a water-cooled radiator, a first stacked busbar, and a second stacked busbar. The switching power supply, control board, water-cooled radiator, first stacked busbar, and second stacked busbar are installed within the support frame. Its distinguishing feature is that... It also includes several discrete IGBT modules, each of which consists of an upper tube and a lower tube; the discrete IGBT modules are composed of DC-side IGBT modules and AC-side IGBT modules, and are evenly arranged on the water-cooled radiator. The first stacked busbar connects the AC side IGBT module and the DC side IGBT module, and the second stacked busbar connects the DC side IGBT module, the DC side support capacitor, and the absorption capacitor; each of the two AC outputs of the discrete IGBT module is equipped with an AC output side copper busbar and a current sensor.

[0006] Furthermore, the discrete IGBT modules are arranged in two rows, with the first row containing eight DC-side IGBT modules and the second row containing four AC-side IGBT modules, forming a triangular arrangement.

[0007] Furthermore, the switching power supply is connected to and supplies power to the control board, voltage sensor, and current sensor; The liquid cooling pipes of the water-cooled radiator are evenly laid at the bottom of the IGBT module according to the direction of the IGBT module.

[0008] Furthermore, a voltage sensor is also installed inside the support frame on one side of the current sensor.

[0009] Furthermore, the first stacked busbar consists of three layers of insulating boards and four copper plates. The upper and lower surfaces of the insulating boards are covered with insulating layers, and the four copper plates are connected in a symmetrical design on the insulating boards.

[0010] Furthermore, the second stacked busbar is composed of three layers of copper plates, and an insulating layer is provided between the copper plates and on the upper and lower surfaces of the second stacked busbar; the uppermost layer is connected to the neutral point, the middle layer is connected to the negative DC bus DC-, and the lowermost layer is connected to the positive DC bus DC+.

[0011] Furthermore, the power module circuit is composed of two single-phase ANPC three-level inverter circuits connected in parallel; it includes an IGBT module, an absorption capacitor, and a support capacitor; The twelve discrete IGBT modules are sequentially designated as VT1, VT2, VT3, VT4, VT5, VT6, VT7, VT8, VT9, VT10, VT11, and VT12; among them, VT1 and VT2 are connected in parallel, as are VT3 and VT4, VT5 and VT6, VT7 and VT8, VT9 and VT10, and VT11 and VT12. The midpoints of the upper and lower tubes of VT1 are connected to the collector of the upper tube of VT5; the midpoints of the upper and lower tubes of VT2 are connected to the collector of the upper tube of VT6; the midpoints of the upper and lower tubes of VT3 are connected to the emitter of the lower tube of VT5; the midpoints of the upper and lower tubes of VT4 are connected to the emitter of the lower tube of VT6; the midpoints of the upper and lower tubes of VT7 are connected to the collector of the upper tube of VT11; the midpoints of the upper and lower tubes of VT8 are connected to the collector of the upper tube of VT12; the midpoints of the upper and lower tubes of VT9 are connected to the emitter of the lower tube of VT11; and the midpoints of the upper and lower tubes of VT10 are connected to the emitter of the lower tube of VT12.

[0012] Furthermore, the supporting capacitors are sequentially named C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 and C12; Support capacitors C1, C2, C3, C7, C8, and C9 are connected from DC+ point to O point, and support capacitors C4, C5, C6, C10, C11, and C12 are installed from O point to DC- point. Furthermore, the absorption capacitors are sequentially designated as CS1, CS2, CS3, CS4, CS5, CS6, CS7, and CS8; CS1 and CS2 are located between the positive DC bus input DC+ and the neutral point O; CS3 and CS4 are located between the DC bus DC- and the neutral point O. CS5 and CS6 are located between the positive DC bus input DC+ and the neutral point O; CS7 and CS8 are located between the DC bus DC- and the neutral point O.

[0013] Furthermore, in one of the ANPC three-level inverter circuits, the equivalent RL parameter of the line from the upper end of the VT1 upper transistor to the positive DC bus input DC+ is the same as that of the line from the upper end of the VT2 upper transistor to the positive DC bus input DC+. The equivalent RL parameters of the line from the lower end of VT1 to the neutral point O are the same as those of the line from the lower end of VT2 to the neutral point O. The equivalent RL parameters of the line from the upper end of the VT3 tube to the neutral point O are the same as those of the line from the upper end of the VT4 tube to the neutral point O. The equivalent RL parameters of the line from the lower end of the VT3 tube to the negative DC bus DC- are the same as those of the line from the lower end of the VT4 tube to the negative DC bus DC-. The equivalent RL parameters of the line output from VT1 to the upper end of the upper tube of VT5 are the same as those of the line output from VT2 to the upper end of the upper tube of VT6. The equivalent RL parameters of the line from VT3 output to the lower end of VT5 are the same as those of the line from VT4 output to the lower end of VT6. Similarly, in another ANPC three-level inverter circuit, the equivalent RL parameter of the line from the upper end of the VT7 upper transistor to the positive DC bus input DC+ is the same as the equivalent RL parameter of the line from the upper end of the VT8 upper transistor to the positive DC bus input DC+. The equivalent RL parameters of the line from the lower end of the VT7 tube to the neutral point O are the same as those of the line from the lower end of the VT8 tube to the neutral point O. The equivalent RL parameters of the line from the upper end of the VT9 upper tube to the neutral point O are the same as those of the line from the upper end of the VT10 upper tube to the neutral point O. The equivalent RL parameter of the line from the lower end of the VT9 tube to the negative DC bus DC- is the same as that of the lower end of the VT10 tube to the negative DC bus DC-. The equivalent RL parameters of the line output from VT7 to the upper end of the upper tube of VT11 are the same as those of the line output from VT8 to the upper end of the upper tube of VT12. The equivalent RL parameters of the line output from VT9 to the lower end of the lower tube of VT11 are the same as those of the line output from VT10 to the lower end of the lower tube of VT12.

[0014] The present invention proposes an ANPC three-level flywheel energy storage power module with IGBT modules directly connected in parallel. Through the internal balanced and symmetrical heat dissipation design and the fully symmetrical layout of IGBT modules, stacked busbars and AC output copper busbars, the parameter consistency of each parallel branch is greatly improved, thereby achieving a very high transient and steady-state current sharing coefficient. In actual measurement, the transient and steady-state current sharing coefficients of all parallel devices are above 0.97.

[0015] The present invention adopts a symmetrical and uniform arrangement of water-cooled heat sinks with symmetrical flow channels and uniform heat dissipation inside the heat sink, which ensures that the junction temperature of all directly parallel IGBT modules is consistent during operation.

[0016] The driving circuit of this invention is installed on the IGBT module. The driving circuit cables are of uniform length and symmetrically laid out. Furthermore, it adopts a method of using one driving circuit to simultaneously control two parallel IGBT modules, which ensures the synchronization and consistency of the driving signals and can further improve the current sharing performance of the IGBT module.

[0017] Through the structural design described above, this invention makes the loop impedances of the two parallel branches in the power module closer in the forward current path, freewheeling current path, and negative current path. All IGBT devices on the four commutation loops of each of the two parallel branches are first connected in series and then in parallel, increasing the total resistance and inductance value on each commutation loop. This results in a smaller impedance deviation rate between the corresponding commutation loops of the two parallel branches and a higher current sharing coefficient. Attached Figure Description

[0018] Figure 1 A rear view of the invention is shown; Figure 2 A front view of the invention is shown; Figure 3 A layout diagram of the present invention is shown; Figure 4 The diagram shows the structure of the first stacked busbar of the present invention; Figure 5 A structural diagram of the second stacked busbar of the present invention is shown; Figure 6 The diagram shows the structure of the copper busbar on the AC output side of this invention; Figure 7 The circuit connection diagram of the present invention is shown. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Furthermore, in the application, the terms "first," "second," and other similar words are not intended to imply any order, quantity, or importance, but are merely used to distinguish different elements, and the terms "upper," "lower," "left," "right," and other similar words are merely positional relationships in the accompanying drawings.

[0021] like Figure 1 , 2 As shown in Figure 3, the present invention provides a flywheel energy storage power module with IGBT modules directly connected in parallel, including a support frame 1, a switching power supply 2, a control board 3, a voltage sensor 4, a current sensor 5, a first stacked busbar 6, a second stacked busbar 7, a support capacitor 8, an absorption capacitor 9, a water-cooled radiator 10, an IGBT module, and an AC output side copper busbar 11, all of which are placed inside the support frame 1.

[0022] There are twelve discrete IGBT modules, each consisting of an upper tube and a lower tube. The twelve discrete IGBT modules are arranged in two rows. VT1~VT4 and VT7~VT10 are DC-side IGBT modules, while VT5, VT6, VT11, and VT12 are AC-side IGBT modules. VT1~VT6 and VT7~VT12 are arranged in a triangular pattern and are evenly distributed on the liquid cooling pipes of the water-cooled radiator.

[0023] The switching power supply 2 supplies power to the control board 3, voltage sensor 4, and current sensor 5. The current sensor 5 is installed at the two AC output copper busbars 11, and the voltage sensor 4 measures the voltage between DC+ and the neutral point O, as well as the voltage between DC+ and DC-. The liquid cooling pipes of the water-cooled radiator 10 are evenly laid at the bottom of the 12 IGBT modules according to the direction of the IGBT modules.

[0024] The first stacked busbar 6 connects the AC-side IGBT module and the DC-side IGBT module. The first stacked busbar 6 consists of three insulating plates 61 and four copper plates 62. The upper and lower surfaces of the insulating plates are covered with insulating layers 63, and the four copper plates are symmetrically arranged on the insulating plates. The symmetrical and consistent design of the four copper plates within the first stacked busbar ensures consistency in stray inductance and equivalent resistance among the parallel IGBTs while minimizing stray inductance.

[0025] The second-layer busbar 7 connects the DC-side IGBT module to the DC-side support capacitor 8 and absorption capacitor 9. The second-layer busbar consists of three copper plates I, with insulating layers I71 between the copper plates I and on the upper and lower surfaces of the second-layer busbar 7. The top layer connects to the neutral point O, the middle layer connects to the negative DC bus DC-, and the bottom layer connects to the positive DC bus DC+. Twelve sets of support capacitors C1~C12 are installed between the positive and negative layers. Support capacitors C1~C3 and C7~C9 are installed from the DC+ point to the O point of the second-layer busbar, and support capacitors C4~C6 and C10~C12 are installed from the O point to the DC- point. The second-layer busbar adopts a symmetrical and consistent design for the connection of the two IGBTs, ensuring consistency in stray inductance and equivalent resistance between the parallel IGBTs while minimizing stray inductance.

[0026] In this invention, the AC output side copper busbar 11 is arranged at both AC output points, and the structure is symmetrical. The AC output side copper busbar summarizes and outputs the AC output current, and a current sensor 5 is installed at each AC output point.

[0027] like Figure 7 As shown, the circuit layout of the power module composed of discrete IGBT modules in this invention adopts a method of directly connecting two IGBT modules in parallel in an ANPC three-level inverter circuit to obtain a larger output current. The entire power module consists of twelve discrete IGBT elements, twelve sets of supporting capacitors, and eight sets of absorption capacitors.

[0028] The twelve discrete IGBT modules are sequentially labeled (VT1, VT2), (VT3, VT4), (VT5, VT6), (VT7, VT8), (VT9, VT10), and (VT11, VT12). These twelve discrete IGBT modules are connected in a first stacked busbar to form two identical bridge arms. All IGBT modules within parentheses are directly connected in parallel. In the power module, VT1, VT2, VT3, VT4, VT7, VT8, VT9, and VT10 are installed in the first row (DC side) from left to right; VT5, VT6, VT11, and VT12 are installed in the second row (AC side) from left to right. The midpoints of the upper and lower transistors of VT1 are connected to the collector of the upper transistor of VT5; the midpoints of the upper and lower transistors of VT2 are connected to the collector of the upper transistor of VT6; the midpoints of the upper and lower transistors of VT3 are connected to the emitter of the lower transistor of VT5; and the midpoints of the upper and lower transistors of VT4 are connected to the emitter of the lower transistor of VT6. Similarly, in the other phase of the ANPC three-level inverter circuit, the midpoint of the upper and lower transistors of VT7 is connected to the collector of the upper transistor of VT11, the midpoint of the upper and lower transistors of VT8 is connected to the collector of the upper transistor of VT12, the midpoint of the upper and lower transistors of VT9 is connected to the emitter of the lower transistor of VT11, and the midpoint of the upper and lower transistors of VT10 is connected to the emitter of the lower transistor of VT12.

[0029] The supporting capacitors are numbered C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, and C12. Supporting capacitors C1, C2, C3, C7, C8, and C9 are connected from DC+ point to O point, and supporting capacitors C4, C5, C6, C10, C11, and C12 are installed from O point to DC- point.

[0030] The absorption capacitors are named CS1, CS2, CS3, CS4, CS5, CS6, CS7 and CS8 in sequence; CS1 is connected in parallel across VT1, CS2 is connected in parallel across VT2, CS3 is connected in parallel across VT3, CS4 is connected in parallel across VT4, CS5 is connected in parallel across VT7, CS6 is connected in parallel across VT8, CS7 is connected in parallel across VT9 and CS8 is connected in parallel across VT10.

[0031] X11 is the equivalent RL parameter of the line from the upper end of the upper transistor of IGBT module VT1 to the positive DC bus input DC+; X12 is the equivalent RL parameter of the line from the upper end of the upper transistor of IGBT module VT2 to the positive DC bus input DC+; X21 is the equivalent RL parameter of the line from the lower end of the lower transistor of IGBT module VT1 to the neutral point O; X22 is the equivalent RL parameter of the line from the lower end of the lower transistor of IGBT module VT2 to the neutral point O. Since the collector and emitter terminals of the two corresponding IGBT modules are directly connected in parallel, the circuit impedance is equal. Therefore, the RL parameters of components X11 and X12 should be the same, and the RL parameters of components X21 and X22 should be the same. X31 is the equivalent RL parameter of the line from the upper end of the upper transistor of IGBT module VT3 to the neutral point O; X32 is the equivalent RL parameter of the line from the upper end of the upper transistor of IGBT module VT4 to the neutral point O; X41 is the equivalent RL parameter of the line from the lower end of the lower transistor of IGBT module VT3 to the negative DC bus DC-; X42 is the equivalent RL parameter of the line from the lower end of the lower transistor of IGBT module VT4 to the negative DC bus DC-. Since the collector and emitter ends of the two corresponding IGBT modules are directly connected in parallel, the loop impedances are equal. The RL parameters of components X31 and X32 should be the same, and the RL parameters of components X41 and X42 should be the same. X51 represents the equivalent RL parameter of the line output from IGBT module VT1 to the upper end of the upper tube of VT5; X52 represents the equivalent RL parameter of the line output from IGBT module VT2 to the upper end of the upper tube of VT6; X61 represents the equivalent RL parameter of the line output from IGBT module VT3 to the lower end of the lower tube of VT5; and X62 represents the equivalent RL parameter of the line output from IGBT module VT4 to the lower end of the lower tube of VT6.

[0032] Because the connection of the four copper plates in the first stacked busbar adopts a symmetrical and consistent design, and the collector and emitter terminals of the two corresponding IGBT modules are directly connected in parallel, the loop impedances are equal. Therefore, the RL parameters of components X51 and X52 should be the same, and the RL parameters of components X61 and X62 should be the same. Similarly, in another ANPC inverter circuit, the RL parameters of components X71 and X72 should be the same, the RL parameters of components X81 and X82 should be the same, the RL parameters of components X91 and X92 should be the same, the RL parameters of components X101 and X102 should be the same, the RL parameters of components X111 and X112 should be the same, and the RL parameters of components X121 and X122 should be the same.

[0033] X131 represents the equivalent RL parameter from VT5 output to L1, and X132 represents the equivalent RL parameter from VT6 output to L1. The AC output side copper busbar structure is as follows: Figure 7As shown, a recess 12 is cut in the middle of the copper busbar. The two sides of the recess 12 adopt a symmetrical design to converge the currents of the two branches into a total current, ensuring the consistency of the impedance parameters of the two AC branches X131 and X132. Similarly, in another ANPC three-level circuit, X141 is the equivalent RL parameter of the output of VT11 to L2, and X142 is the equivalent RL parameter of the output of VT12 to L2. The RL parameters of components X141 and X142 are the same.

[0034] The drive circuit is installed on the IGBT module. The drive circuit cables are of uniform length and symmetrically laid out. The method of using one drive circuit to control two parallel IGBT modules at the same time ensures the synchronization and consistency of the drive signal, which can further improve the current sharing performance of the IGBT module.

[0035] Twelve discrete IGBT modules share a single water-cooled heatsink. The heatsink has uniform internal flow channels, providing identical heat dissipation conditions for all twelve modules. This strengthens thermal coupling between the devices and ensures consistent junction temperatures across the modules during operation. Under these conditions, the symmetrical layout of the twelve discrete IGBT modules and the first stacked busbar achieves identical values ​​for X11 and X12, X51 and X52, and X131 and X132, with equal loop impedances for the forward current paths of the two parallel branches; identical values ​​for X21 and X22, X31 and X32, and equal loop impedances for the freewheeling current paths of the two parallel branches; identical values ​​for X41 and X42, and X61 and X62, with equal loop impedances for the negative current paths of the two parallel branches. Similarly, in another ANPC three-level inverter circuit, the loop impedance of each current path is equal.

[0036] Point O is the neutral point. Each supporting capacitor has the same model. The second stacked busbar adopts a symmetrical layout design, which ensures that the values ​​of X1, X2, X3, and X4 are consistent, and the values ​​of X5, X6, X7, and X8 are consistent, thus ensuring the equal voltage distribution at the neutral point O.

[0037] This invention employs a circuit layout of discrete IGBT modules to form a power module. The direct parallel connection of two IGBT modules ensures that the power module can output a larger current. The symmetrical layout of the drive circuit, the first stacked busbar, the second stacked busbar, and the AC side busbar greatly improves the parameter consistency of each branch, achieving a very high current sharing coefficient for the parallel circuit of this module.

[0038] This invention features 12 IGBTs evenly and symmetrically arranged in a bottom water-cooled heat sink, ensuring consistent heat transfer coefficients and thus guaranteeing the dynamic and static current sharing performance of the parallel IGBTs from a heat dissipation perspective. The parallel IGBT modules are simultaneously controlled by the same drive circuit, ensuring the synchronization and consistency of the drive signals, which further improves the current sharing performance of the IGBT modules.

[0039] The supporting frame of this invention is made of sheet metal, which can effectively resist external electromagnetic interference and also shield internal electromagnetic interference from the module. Sheet metal is universal, aesthetically pleasing, easy to manufacture, and cost-effective. The main circuit layout design makes full use of space, optimizes the circuit path, and results in a module with high power density, small overall size, simplicity, easy maintenance and installation, and excellent electrical characteristics.

[0040] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A flywheel energy storage power module with IGBT modules directly connected in parallel, comprising a support frame, a switching power supply, a control board, a water-cooled heat sink, a first stacked busbar, and a second stacked busbar, wherein the switching power supply, control board, water-cooled heat sink, first stacked busbar, and second stacked busbar are installed within the support frame; characterized in that... ； It also includes several discrete IGBT modules, each of which consists of an upper tube and a lower tube; the discrete IGBT modules are composed of DC-side IGBT modules and AC-side IGBT modules, and are evenly arranged on the water-cooled radiator. The first stacked busbar connects the AC side IGBT module and the DC side IGBT module, and the second stacked busbar connects the DC side IGBT module, the DC side support capacitor, and the absorption capacitor; each of the two AC outputs of the discrete IGBT module is equipped with an AC output side copper busbar and a current sensor.

2. The flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 1, characterized in that, The discrete IGBT modules are arranged in two rows, with the first row containing eight DC-side IGBT modules and the second row containing four AC-side IGBT modules, forming a triangular arrangement.

3. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 1, characterized in that, The switching power supply is connected to and supplies power to the control board, voltage sensor, and current sensor; The liquid cooling pipes of the water-cooled radiator are evenly laid at the bottom of the IGBT module according to the direction of the IGBT module.

4. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 1, characterized in that, A voltage sensor is also installed inside the support frame on one side of the current sensor.

5. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 1, characterized in that, The first stacked busbar consists of three layers of insulating boards and four copper plates. The upper and lower surfaces of the insulating boards are covered with insulating layers, and the four copper plates are connected in a symmetrical design on the insulating boards.

6. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 1, characterized in that, The second stacked busbar is composed of three layers of copper plates, and an insulating layer is provided between the copper plates and on the upper and lower surfaces of the second stacked busbar; the top layer is connected to the neutral point, the middle layer is connected to the negative DC bus DC-, and the bottom layer is connected to the positive DC bus DC+.

7. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 6, characterized in that, The power module circuit consists of two single-phase ANPC three-level inverter circuits connected in parallel; it includes an IGBT module, an absorption capacitor, and a support capacitor. The twelve discrete IGBT modules are sequentially designated as VT1, VT2, VT3, VT4, VT5, VT6, VT7, VT8, VT9, VT10, VT11, and VT12; among them, VT1 and VT2 are connected in parallel, as are VT3 and VT4, VT5 and VT6, VT7 and VT8, VT9 and VT10, and VT11 and VT12. The midpoints of the upper and lower tubes of VT1 are connected to the collector of the upper tube of VT5; the midpoints of the upper and lower tubes of VT2 are connected to the collector of the upper tube of VT6; the midpoints of the upper and lower tubes of VT3 are connected to the emitter of the lower tube of VT5; the midpoints of the upper and lower tubes of VT4 are connected to the emitter of the lower tube of VT6; the midpoints of the upper and lower tubes of VT7 are connected to the collector of the upper tube of VT11; the midpoints of the upper and lower tubes of VT8 are connected to the collector of the upper tube of VT12; the midpoints of the upper and lower tubes of VT9 are connected to the emitter of the lower tube of VT11; and the midpoints of the upper and lower tubes of VT10 are connected to the emitter of the lower tube of VT12.

8. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 7, characterized in that, The supporting capacitors are sequentially named C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 and C12; Support capacitors C1, C2, C3, C7, C8, and C9 are connected from DC+ point to O point, and support capacitors C4, C5, C6, C10, C11, and C12 are installed from O point to DC- point.

9. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 7, characterized in that, The absorption capacitors are sequentially designated as CS1, CS2, CS3, CS4, CS5, CS6, CS7, and CS8; CS1 and CS2 are located between the positive DC bus input DC+ and the neutral point O; CS3 and CS4 are located between the DC bus DC- and the neutral point O. CS5 and CS6 are located between the positive DC bus input DC+ and the neutral point O; CS7 and CS8 are located between the DC bus DC- and the neutral point O.

10. A flywheel energy storage power module with IGBT modules directly connected in parallel according to claim 9, characterized in that, In one of the ANPC three-level inverter circuits, the equivalent RL parameter of the line from the upper end of the VT1 upper transistor to the positive DC bus input DC+ is the same as that of the line from the upper end of the VT2 upper transistor to the positive DC bus input DC+. The equivalent RL parameters of the line from the lower end of VT1 to the neutral point O are the same as those of the line from the lower end of VT2 to the neutral point O. The equivalent RL parameters of the line from the upper end of the VT3 tube to the neutral point O are the same as those of the line from the upper end of the VT4 tube to the neutral point O. The equivalent RL parameters of the line from the lower end of the VT3 tube to the negative DC bus DC- are the same as those of the line from the lower end of the VT4 tube to the negative DC bus DC-. The equivalent RL parameters of the line output from VT1 to the upper end of the upper tube of VT5 are the same as those of the line output from VT2 to the upper end of the upper tube of VT6. The equivalent RL parameters of the line from VT3 output to the lower end of VT5 are the same as those of the line from VT4 output to the lower end of VT6. Similarly, in another ANPC three-level inverter circuit, the equivalent RL parameter of the line from the upper end of the VT7 upper transistor to the positive DC bus input DC+ is the same as the equivalent RL parameter of the line from the upper end of the VT8 upper transistor to the positive DC bus input DC+. The equivalent RL parameters of the line from the lower end of the VT7 tube to the neutral point O are the same as those of the line from the lower end of the VT8 tube to the neutral point O. The equivalent RL parameters of the line from the upper end of the VT9 upper tube to the neutral point O are the same as those of the line from the upper end of the VT10 upper tube to the neutral point O. The equivalent RL parameter of the line from the lower end of the VT9 tube to the negative DC bus DC- is the same as that of the lower end of the VT10 tube to the negative DC bus DC-. The equivalent RL parameters of the line output from VT7 to the upper end of the upper tube of VT11 are the same as those of the line output from VT8 to the upper end of the upper tube of VT12. The equivalent RL parameters of the line output from VT9 to the lower end of the lower tube of VT11 are the same as those of the line output from VT10 to the lower end of the lower tube of VT12.

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