A three-terminal two-switch energy storage sub-module and a transcranial magnetic stimulation circuit cascaded by the same

Abstract

This invention discloses a three-terminal, two-switch energy storage submodule and its cascaded transcranial magnetic stimulation (TMS) circuit. The energy storage submodule includes an energy storage capacitor, a first bridge arm, and a second bridge arm. The first and second bridge arms are respectively composed of a unidirectional power semiconductor device and a unidirectional actively controllable switch device. One bridge arm is configured as a split bridge arm, and the other as a common bridge arm. By leading out the middle connection terminals of the two power devices in the split bridge arm and leading out the connection nodes of the two power devices in the common bridge arm, an energy storage submodule with three external connection terminals is formed. Multiple energy storage submodules are cascaded through a fixed-port connection method, allowing the construction of a cascaded energy storage structure without changing the internal connection relationships of the energy storage submodules. This invention achieves modular expansion of the energy storage unit through the three-terminal, two-switch energy storage submodule, providing a cascaded energy storage topology with a fixed structure and easy expansion for transcranial magnetic stimulation pulse power supplies.

Description

Technical Field

[0001] This invention relates to the field of transcranial magnetic stimulation (TMS) technology, specifically to a three-terminal two-switch energy storage submodule and its cascaded transcranial magnetic stimulation circuit. Background Technology

[0002] Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique that uses pulsed current to generate a rapidly changing magnetic field in a coil, which in turn induces an electric field in brain tissue. To improve stimulation effectiveness and achieve different stimulation modes, TMS pulse power supplies typically need to have high output voltage, rapid current build-up capability, and flexible pulse waveform adjustment capability.

[0003] Existing transcranial magnetic stimulation (TMS) pulsed power supplies typically employ a discharge circuit composed of an energy storage capacitor and a power switch. A pulsed magnetic field is generated by controlling the energy storage capacitor to release energy to the stimulation coil. For a single energy storage unit structure, the output pulse amplitude is primarily limited by the voltage level of a single energy storage capacitor. When it is necessary to increase the stimulation intensity or expand the output capability, it is usually necessary to increase the energy storage voltage level, thereby increasing the voltage withstand requirements of the power devices and the complexity of the system design.

[0004] To improve output voltage levels and system scalability, modular energy storage structures are increasingly being applied to transcranial magnetic stimulation (TMS) pulse power supplies. By cascading multiple energy storage submodules, the stored voltages can be superimposed, increasing the terminal voltage during coil excitation. However, existing modular energy storage structures typically require changes to the connections between modules depending on different operating states, or rely on additional power switches for module reconfiguration. This results in complex submodule interfaces and necessitates additional control channels and drive circuits during module expansion, reducing the consistency and versatility of modular designs.

[0005] Furthermore, during transcranial magnetic stimulation (TMS), the coil current typically exhibits an asymmetrical operating characteristic of rapid current establishment and slow current decay. That is, a higher voltage is required to quickly establish the current during the excitation phase, while a lower reverse voltage is usually sufficient for current decay during the energy release phase. Therefore, not all applications require energy storage modules with complex bidirectional reconfiguration capabilities; instead, a simple, standardized, and easily cascaded energy storage module structure is needed.

[0006] Therefore, it is necessary to propose an energy storage submodule with a fixed external connection interface. By rationally designing the connection relationship of the power devices inside the module, multiple energy storage submodules can be cascaded without changing the internal topology, thereby meeting the modular expansion requirements of transcranial magnetic stimulation pulse power supply. Summary of the Invention

[0007] The present invention aims to provide a three-terminal two-switch energy storage submodule and its cascaded transcranial magnetic stimulation circuit to solve the problems of complex interfaces and difficulty in cascading expansion of existing modular energy storage structures.

[0008] The technical solution to achieve the purpose of this invention is as follows:

[0009] A three-terminal, two-switch energy storage submodule for cascading transcranial magnetic stimulation circuits includes an energy storage capacitor, a first bridge arm, and a second bridge arm, wherein the energy storage capacitor has a positive terminal and a negative terminal.

[0010] The first bridge arm includes a first unidirectional uncontrolled power semiconductor device and a first unidirectional active controllable switch device, wherein the cathode of the first unidirectional uncontrolled power semiconductor device is connected to the positive terminal node of the energy storage capacitor, and one end of the first unidirectional active controllable switch device is connected to the negative terminal node of the energy storage capacitor; the first unidirectional active controllable switch device has a unidirectional conduction direction from one end near the middle of the first bridge arm to the negative terminal node of the energy storage capacitor.

[0011] The second bridge arm includes a second unidirectional active controllable switch and a second unidirectional uncontrolled power semiconductor device, wherein one end of the second unidirectional active controllable switch is connected to the positive terminal of the energy storage capacitor, and the anode of the second unidirectional uncontrolled power semiconductor device is connected to the negative terminal of the energy storage capacitor; the second unidirectional active controllable switch has a unidirectional conduction direction from the positive terminal of the energy storage capacitor to one end of the second bridge arm near the middle.

[0012] One of the first bridge arm and the second bridge arm is a split bridge arm, and the other is a common bridge arm; the two power devices in the split bridge arm are led out at the ends near the middle of the bridge arm to form a first split end and a second split end, respectively; the two power devices in the common bridge arm are connected to each other at the ends near the middle of the bridge arm and are led out to form a common end.

[0013] The first split end, the second split end, and the common connection end constitute the three external connection ends of the energy storage submodule. The three external connection ends are set independently of each other. The three external connection ends are used to cascade with multiple energy storage submodules without changing the connection relationship between the power semiconductor devices inside the energy storage submodule.

[0014] Furthermore, the first bridge arm is a split bridge arm, and the second bridge arm is a common bridge arm;

[0015] The first unidirectional uncontrolled power semiconductor device in the first bridge arm is led out at one end near the middle of the first bridge arm to form a first split terminal; the first unidirectional active controllable switching device in the first bridge arm is led out at one end near the middle of the first bridge arm to form a second split terminal;

[0016] The second unidirectional active controllable switching device in the second bridge arm is connected in series with the second unidirectional uncontrolled power semiconductor device in the second bridge arm, and their connection nodes are led out to form a common terminal.

[0017] Furthermore, the first bridge arm is a common bridge arm, and the second bridge arm is a split bridge arm;

[0018] The first unidirectional uncontrolled power semiconductor device and the first unidirectional active controllable switch device in the first bridge arm are connected in series, and their connection nodes are led out to form a common terminal.

[0019] The second unidirectional uncontrolled power semiconductor device in the second bridge arm is led out at one end near the middle of the second bridge arm to form a first split terminal; the second unidirectional active controllable switch device in the second bridge arm is led out at one end near the middle of the second bridge arm to form a second split terminal.

[0020] Furthermore, the active controllable switching devices provided in each of the energy storage submodules include only the first unidirectional active controllable switching device and the second unidirectional active controllable switching device, and the energy storage submodules do not provide other active controllable switching devices for changing the electrical connection relationship between the first split terminal, the second split terminal and the common terminal.

[0021] Furthermore, both the first unidirectional active controllable switch and the second unidirectional active controllable switch are composed of power semiconductor switch devices that have reverse blocking capability or achieve unidirectional current blocking characteristics through device combination.

[0022] Furthermore, the first unidirectional active controllable switching device and the second unidirectional active controllable switching device include, but are not limited to, MOSFETs, IGBTs, IGCTs, and SiC power switching devices.

[0023] Furthermore, the first unidirectional uncontrolled power semiconductor device and the second unidirectional uncontrolled power semiconductor device are diodes, fast recovery diodes, Schottky diodes, or other power semiconductor devices with unidirectional conductivity characteristics.

[0024] A transcranial magnetic stimulation circuit includes a stimulation coil and N energy storage submodules SM1 to SM2 connected in series. N Where N≥2;

[0025] The energy storage submodule adopts the three-terminal two-switch energy storage submodule; adjacent energy storage submodules are cascaded according to a preset port connection relationship, wherein the second split end and the common connection end of adjacent energy storage submodules are connected to form a continuous cascaded energy storage structure; the energy storage submodules at both ends of the cascaded energy storage structure are respectively connected to the stimulation coil.

[0026] Furthermore, adjacent energy storage submodules are connected by fixed ports. The energy storage submodules do not have active reconfiguration switches inside them to change the electrical connection between the first split end, the second split end, and the common connection end. The port connection between each energy storage submodule and the connection between the energy storage submodule and the energy storage nodes of adjacent energy storage submodules remain fixed during operation.

[0027] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention adopts a three-terminal two-switch energy storage sub-module, and each sub-module is equipped with only two active controllable switching devices, which reduces the number of power switches, drive circuits and control channels, and simplifies the module structure; (2) The present invention has the characteristics of unified structure, simple control and convenient expansion. The output voltage and energy storage capacity can be changed by adjusting the number of energy storage sub-modules, and it is suitable for transcranial magnetic stimulation pulse power supplies of different power levels. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the basic components of a three-terminal, two-switch energy storage submodule.

[0029] Figure 2 This is a schematic diagram of the first type of three-terminal two-switch energy storage submodule. The first bridge arm is set as a split bridge arm, and the second bridge arm is set as a common bridge arm.

[0030] Figure 3 This is a schematic diagram of the second type of three-terminal two-switch energy storage submodule. The first bridge arm is set as a common bridge arm, and the second bridge arm is set as a split bridge arm.

[0031] Figure 4 The diagram shows a transcranial magnetic stimulation circuit cascaded using the first type of three-terminal two-switch energy storage submodule as the basic unit.

[0032] Figure 5 This is a circuit diagram of a transcranial magnetic stimulation system cascaded using the second type of three-terminal two-switch energy storage submodule as the basic unit.

[0033] Figure 6 This is a schematic diagram of the charging control of the stimulation coil under the cascading of four first-type three-terminal two-switch energy storage sub-modules.

[0034] Figure 7 This is a schematic diagram of the discharge control of the stimulation coil under the cascading of four first-type three-terminal two-switch energy storage sub-modules.

[0035] Figure 8 This is a schematic diagram of the charging control of the stimulation coil under the cascading of four second-type three-terminal two-switch energy storage sub-modules.

[0036] Figure 9 This is a schematic diagram of the discharge control of the stimulation coil under the cascading of four second-type three-terminal two-switch energy storage sub-modules.

[0037] Figure 10 This is a schematic diagram of the voltage on the stimulation coil during the charging and discharging process of four cascaded first-type three-terminal two-switch energy storage sub-modules.

[0038] Figure 11 This is a schematic diagram of the current in the stimulation coil during the charging and discharging process of four cascaded first-type three-terminal two-switch energy storage sub-modules.

[0039] Figure 12 This is a schematic diagram of the voltage across the four capacitors during the charging and discharging process of four cascaded first-type three-terminal two-switch energy storage submodules.

[0040] Figure 13 This is a schematic diagram of the current in the four capacitors during the charging and discharging process of four first-type three-terminal two-switch energy storage sub-modules cascaded together. Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the protection scope of the present invention.

[0042] Example 1

[0043] This invention proposes a transcranial magnetic stimulation (TMS) circuit, comprising multiple three-terminal, two-switch energy storage submodules and a stimulation coil. The multiple energy storage submodules are cascaded via fixed-port connections to form a modular energy storage structure, used to provide pulsed excitation energy to the TMS coil.

[0044] like Figure 1 As shown, the three-terminal two-switch energy storage submodule includes an energy storage capacitor, a first bridge arm, and a second bridge arm. The energy storage capacitor has a positive terminal P and a negative terminal N, and the first bridge arm and the second bridge arm are respectively connected between the positive terminal P and the negative terminal N of the energy storage capacitor.

[0045] The first bridge arm includes a first unidirectional uncontrolled power semiconductor device D1 (e.g., a power diode) and a first unidirectional actively controllable switch S1. The first unidirectional uncontrolled power semiconductor device D1 is connected between the positive node P of the energy storage capacitor and the middle of the first bridge arm, and the first unidirectional actively controllable switch S1 is connected between the middle of the first bridge arm and the negative node N of the energy storage capacitor. The first unidirectional actively controllable switch S1 has a unidirectional conduction direction pointing from one end near the middle of the first bridge arm to the negative node N of the energy storage capacitor.

[0046] The second bridge arm includes a second unidirectional active controllable switch S2 and a second unidirectional uncontrolled power semiconductor device D2. The second unidirectional active controllable switch S2 is connected between the positive node P of the energy storage capacitor and the middle of the second bridge arm, and the second unidirectional uncontrolled power semiconductor device D2 is connected between the middle of the second bridge arm and the negative node N of the energy storage capacitor. The second unidirectional active controllable switch S2 has a unidirectional conduction direction pointing from the positive node P of the energy storage capacitor towards one end near the middle of the second bridge arm.

[0047] The first unidirectional uncontrolled power semiconductor device D1 and the second unidirectional uncontrolled power semiconductor device D2 can be implemented using diodes, fast recovery diodes, Schottky diodes, or other power semiconductor devices with unidirectional conductivity characteristics; the first unidirectional active controllable switch device S1 and the second unidirectional active controllable switch device S2 can be power semiconductor devices with reverse blocking capability, or can be combined with active switch devices and series diodes, reverse series switch devices, etc. to form a switch unit with unidirectional current blocking characteristics.

[0048] Example 2

[0049] like Figure 2 As shown, in one embodiment, a three-port energy storage submodule is provided, wherein the first bridge arm of the submodule is configured as a split bridge arm and the second bridge arm is configured as a common bridge arm.

[0050] In the first bridge arm, one end of the first unidirectional uncontrolled power semiconductor device D1 is connected to the positive terminal P of the energy storage capacitor, and the other end is located in the middle of the first bridge arm, forming the first split terminal C; one end of the first unidirectional active controllable switch device S1 is connected to the negative terminal N of the energy storage capacitor, and the other end is located in the middle of the first bridge arm, forming the second split terminal A.

[0051] In the second bridge arm, one end of the second active controllable switching device S2 is connected to the positive terminal P of the energy storage capacitor; one end of the second unidirectional uncontrolled power semiconductor device D2 is connected to the negative terminal N of the energy storage capacitor; the other end of the second active controllable switching device S2 is connected to the other end of the second unidirectional uncontrolled power semiconductor device D2, and their connection nodes are led out to form a common terminal B.

[0052] Thus, the energy storage submodule forms three external connection terminals A, B and C.

[0053] Example 3

[0054] like Figure 3 As shown, in this embodiment, a second three-port energy storage submodule is provided, wherein the first bridge arm of the submodule is configured as a common bridge arm, and the second bridge arm is configured as a split bridge arm.

[0055] In the first bridge arm, one end of the first unidirectional uncontrolled power semiconductor device D1 is connected to the positive terminal P of the energy storage capacitor; one end of the first unidirectional active controllable switch device S1 is connected to the negative terminal N of the energy storage capacitor; the other end of the first active controllable switch device S1 is connected to the other end of the first unidirectional uncontrolled power semiconductor device D1, and their connection nodes are led out to form a common terminal B.

[0056] In the second bridge arm, one end of the second active controllable switching device S2 is connected to the positive terminal P of the energy storage capacitor, and the other end is located in the middle of the second bridge arm, forming the second split terminal A; one end of the second unidirectional uncontrolled power semiconductor device D2 is connected to the negative terminal N of the energy storage capacitor, and the other end is located in the middle of the second bridge arm, forming the first split terminal C.

[0057] Thus, the energy storage submodule forms three external connection terminals A, B and C.

[0058] This implementation method forms a mirror structure with Embodiment 1, but the functional definitions of the three external connection terminals remain consistent. That is, the second split terminal A corresponds to the connection terminal of the unidirectional active controllable switching device, the first split terminal C corresponds to the connection terminal of the unidirectional uncontrolled power semiconductor device, and the common connection terminal B corresponds to the connection node of the two devices.

[0059] like Figure 4 and Figure 5 As shown, multiple three-terminal, two-switch energy storage submodules are cascaded according to a preset port connection relationship to form a modular cascaded energy storage structure. The three-terminal, two-switch energy storage submodules can adopt the structural form described in Embodiment 2 or Embodiment 3 above.

[0060] Example 4

[0061] This embodiment provides a transcranial magnetic stimulation circuit cascaded with energy storage submodules from Embodiment 2, such as... Figure 4 As shown, the energy storage submodule adopts a structure where the first bridge arm is a split bridge arm and the second bridge arm is a common bridge arm. From the upper left, submodules are labeled counter-clockwise as SM1 to SM2. N Adjacent energy storage submodules are connected via fixed ports. The second split terminal A of the preceding energy storage submodule is connected to the common terminal B of the following energy storage submodule, forming a continuous cascaded energy storage structure. For example, the second split terminal A of the first-stage energy storage submodule SM1 is connected to the common terminal B of the second-stage energy storage submodule SM2, the second split terminal A of the second-stage energy storage submodule SM2 is connected to the common terminal B of the third-stage energy storage submodule SM3, and so on. The common terminal B of the first-stage energy storage submodule SM1 is connected to the starting terminal X1 of the stimulation coil, and the last-stage energy storage submodule SM... NThe first split terminal C is short-circuited with the second split terminal A and connected to the tail end X2 of the stimulation coil. The first split terminal C of the first-stage energy storage submodule SM1 is connected to the positive terminal of the capacitor of the second-stage energy storage submodule SM2, and the first split terminal C of the second-stage energy storage submodule SM2 is connected to the positive terminal of the capacitor of the third-stage energy storage submodule SM3, and so on. The first split terminal, the second split terminal, and the common terminal of each energy storage submodule each assume a fixed port connection function during the cascading process.

[0062] Example 5

[0063] This embodiment provides a transcranial magnetic stimulation circuit cascaded with the energy storage submodules of Embodiment 3. It is a mirror image of the implementation in Embodiment 4, with the functional definitions of the three external connection terminals remaining consistent. Figure 5 As shown. From the top left, the submodules are labeled counter-clockwise as SM1 to SM2. N In this structure, the functional definitions of each external connection terminal are consistent with those in Embodiment 4, namely, the first split terminal C corresponds to the connection terminal of the unidirectional uncontrolled power semiconductor device, the second split terminal A corresponds to the connection terminal of the unidirectional active controllable switching device, and the common connection terminal B corresponds to the connection node of the two power devices. Therefore, adjacent energy storage submodules are still cascaded according to the preset port connection relationship. The common connection terminal of the previous energy storage submodule is connected to the second split terminal A of the next energy storage submodule, forming a continuous cascaded energy storage structure: the common connection terminal B of the first-level energy storage submodule SM1 is connected to the second split terminal A of the second-level energy storage submodule SM2, the common connection terminal B of the second-level energy storage submodule SM2 is connected to the second split terminal A of the third-level energy storage submodule SM3, and so on. The first split terminal C of the first-level energy storage submodule SM1 is short-circuited with the second split terminal A and connected to the first end X1 of the stimulation coil, and the last-level energy storage submodule SM1 is connected to the second split terminal A of the third-level energy storage submodule SM3. N The common terminal is connected to the tail end X2 of the stimulation coil. The first split terminal C of the second-stage energy storage submodule SM2 is connected to the negative terminal of the capacitor of the third-stage energy storage submodule SM3, and the first split terminal C of the third-stage energy storage submodule SM3 is connected to the negative terminal of the capacitor of the fourth-stage energy storage submodule SM4, and so on. The first split terminal, second split terminal, and common terminal of each energy storage submodule respectively undertake fixed port connection functions during the cascading process.

[0064] In both cascading methods of Embodiments 4 and 5, the connection relationships between the first unidirectional uncontrolled power semiconductor device, the second unidirectional uncontrolled power semiconductor device, the first unidirectional active controllable switch device, and the second unidirectional active controllable switch device within each energy storage submodule remain fixed. During the cascading process, there is no need to change the power connection relationship between the first split terminal, the second split terminal, and the common terminal through an additional active switch.

[0065] The resulting cascaded energy storage structure is connected to stimulation coils at both ends. Through the series superposition of the energy storage voltages of multiple energy storage sub-modules, the applied voltage during the coil excitation stage is increased, thereby enabling the rapid establishment of the stimulation coil current.

[0066] In the cascaded transcranial magnetic stimulation circuit composed of the above-mentioned three-terminal two-switch energy storage submodules, by controlling the conduction state of the first unidirectional active controllable switch and the second unidirectional active controllable switch in each energy storage submodule, multiple energy storage submodules can work together to achieve pulse current excitation of the stimulation coil.

[0067] During the excitation phase, each energy storage submodule operates according to a preset control sequence, so that each energy storage capacitor is connected in series with the same polarity. The energy storage voltages of multiple energy storage submodules are superimposed and applied to both ends of the stimulation coil, thereby increasing the coil terminal voltage and realizing the rapid establishment of coil current.

[0068] During the coil current decay phase, the active controllable switching device is turned off, allowing the current to flow along the freewheeling path formed by the unidirectional power semiconductor devices inside the energy storage submodule. Since the energy storage submodules are connected via fixed ports, the internal connection structure of the energy storage module does not need to be altered to complete the energy transfer process.

[0069] To verify the effectiveness of the proposed three-terminal two-switch energy storage submodule and its cascaded transcranial magnetic stimulation circuit, a corresponding simulation model was established for verification.

[0070] like Figure 6 and Figure 7 As shown, the overall circuit simulation model of the cascaded four first-type three-terminal two-switch energy storage sub-modules is presented. Figure 6 In the process, all energy storage capacitors were pre-charged to 1000V, each energy storage submodule was connected according to the above fixed port connection method, and all the first and second unidirectional active controllable switching devices of all submodules were turned on, realizing the charging of the stimulation coil to 4000V. Figure 7 In this process, by changing the switching states of the first and second unidirectional active controllable switching devices of all sub-modules, a discharge of -1000V to the stimulation coil was achieved.

[0071] like Figure 8 and Figure 9 As shown, the overall circuit simulation model of the cascaded four second-type three-terminal two-switch energy storage sub-modules is presented. Figure 8 In the process, all energy storage capacitors were pre-charged to 1000V, each energy storage submodule was connected according to the above fixed port connection method, and all the first and second unidirectional active controllable switching devices of all submodules were turned on, realizing the charging of the stimulation coil to 4000V. Figure 9In this process, by changing the switching states of the first and second unidirectional active controllable switching devices of all sub-modules, a discharge of -1000V to the stimulation coil was achieved.

[0072] like Figure 10 As shown, the voltage change on the stimulation coil during the operation of the overall circuit after cascading four first-type three-terminal two-switch energy storage sub-modules is given. Among them, a 4000V excitation voltage of 2us is applied to the stimulation coil, and a 1000V voltage of 8us in the opposite direction is applied to the stimulation coil to cause the coil current to decay, which is defined as test mode one.

[0073] like Figure 11 As shown, the current change on the stimulation coil during the operation of the overall circuit after cascading four first-type three-terminal two-switch energy storage sub-modules is presented. In the test mode, the current enables fast charging and slow discharging.

[0074] like Figure 12 As shown, the waveforms of the terminal voltage changes for four of the first type of three-terminal two-switch energy storage submodules are presented. During the excitation phase, the output voltages of multiple energy storage submodules are superimposed, increasing the coil terminal voltage, but the capacitor voltage drops slightly due to the series discharge of the capacitors. During the coil energy release phase, the circuit forms a freewheeling loop through the fixed port, and the capacitor begins to charge. Due to the different number of diodes passing through the charging loop, there are differences in capacitor charging, but the overall difference is not significant.

[0075] like Figure 13 As shown, the current variation waveforms of four first-type three-terminal two-switch energy storage submodules are presented. During the excitation stage, the output voltages of multiple energy storage submodules are superimposed, which increases the coil terminal voltage. However, the capacitors discharge in series, and the current rises rapidly. During the coil energy release stage, the circuit forms a freewheeling loop through the fixed port, and the capacitors begin to charge. Due to the different number of diodes passing through the charging loop, the capacitors charge differently. The capacitors bearing the negative voltage charge quickly, while the other capacitors charge slowly.

[0076] The simulation results show that the proposed three-terminal two-switch energy storage submodule can achieve cascading of multiple modules without changing the connection relationship of internal power devices, and meet the requirements of transcranial magnetic stimulation pulse power supply for high-voltage pulse excitation.

[0077] The above embodiments illustrate the basic working principle of the present invention. It should be noted that the core of the present invention lies in utilizing a unidirectional power semiconductor device to naturally change its conduction state according to the circuit state, thereby achieving a natural transition between series output and parallel recycling of energy storage capacitors of the same polarity, rather than relying on an additional active reconfiguration switch to change the energy storage structure.

Claims

1. A three-terminal, two-switch energy storage submodule for cascading transcranial magnetic stimulation circuits, characterized in that, It includes an energy storage capacitor, a first bridge arm, and a second bridge arm, wherein the energy storage capacitor has a positive terminal and a negative terminal. The first bridge arm includes a first unidirectional uncontrolled power semiconductor device and a first unidirectional active controllable switch device, wherein the cathode of the first unidirectional uncontrolled power semiconductor device is connected to the positive terminal node of the energy storage capacitor, and one end of the first unidirectional active controllable switch device is connected to the negative terminal node of the energy storage capacitor; the first unidirectional active controllable switch device has a unidirectional conduction direction pointing from one end near the middle of the first bridge arm to the negative terminal node of the energy storage capacitor; The second bridge arm includes a second unidirectional active controllable switch and a second unidirectional uncontrolled power semiconductor device, wherein one end of the second unidirectional active controllable switch is connected to the positive terminal of the energy storage capacitor, and the anode of the second unidirectional uncontrolled power semiconductor device is connected to the negative terminal of the energy storage capacitor; the second unidirectional active controllable switch has a unidirectional conduction direction from the positive terminal of the energy storage capacitor to one end of the second bridge arm near the middle. One of the first bridge arm and the second bridge arm is a split bridge arm, and the other is a common bridge arm; the two power devices in the split bridge arm are led out at the ends near the middle of the bridge arm to form a first split end and a second split end, respectively; the two power devices in the common bridge arm are connected to each other at the ends near the middle of the bridge arm and are led out to form a common end. The first split end, the second split end, and the common connection end constitute the three external connection ends of the energy storage submodule. The three external connection ends are set independently and are used to cascade multiple energy storage submodules without changing the connection relationship between the unidirectional uncontrolled power semiconductor devices inside the energy storage submodule.

2. The three-terminal, two-switch energy storage submodule according to claim 1, characterized in that, The first bridge arm is a split bridge arm, and the second bridge arm is a common bridge arm; The first unidirectional uncontrolled power semiconductor device in the first bridge arm is led out at one end near the middle of the first bridge arm to form a first split terminal; the first unidirectional active controllable switching device in the first bridge arm is led out at one end near the middle of the first bridge arm to form a second split terminal; The second unidirectional active controllable switching device in the second bridge arm is connected in series with the second unidirectional uncontrolled power semiconductor device in the second bridge arm, and their connection nodes are led out to form a common terminal.

3. The three-terminal, two-switch energy storage submodule according to claim 1, characterized in that, The first bridge arm is a common bridge arm, and the second bridge arm is a split bridge arm; The first unidirectional uncontrolled power semiconductor device and the first unidirectional active controllable switch device in the first bridge arm are connected in series, and their connection nodes are led out to form a common terminal. The second unidirectional uncontrolled power semiconductor device in the second bridge arm is led out at one end near the middle of the second bridge arm to form a first split terminal; the second unidirectional active controllable switch device in the second bridge arm is led out at one end near the middle of the second bridge arm to form a second split terminal.

4. The three-terminal, two-switch energy storage submodule according to claim 1, characterized in that, The energy storage submodule does not include any other actively controllable switching devices for changing the electrical connection relationship between the first split terminal, the second split terminal, and the common terminal.

5. The three-terminal, two-switch energy storage submodule according to claim 1, characterized in that, Both the first unidirectional active controllable switching device and the second unidirectional active controllable switching device are composed of power semiconductor switching devices with reverse blocking capability or unidirectional current blocking characteristics achieved through device combination.

6. The three-terminal, two-switch energy storage submodule according to claim 5, characterized in that, The first unidirectional active controllable switching device and the second unidirectional active controllable switching device are MOSFET, IGBT, IGCT or SiC power switching devices.

7. The three-terminal, two-switch energy storage submodule according to claim 1, characterized in that, The first unidirectional uncontrolled power semiconductor device and the second unidirectional uncontrolled power semiconductor device are diodes, fast recovery diodes, Schottky diodes or other power semiconductor devices with unidirectional conductivity characteristics.

8. A transcranial magnetic stimulation circuit, characterized in that, Includes a stimulation coil and N energy storage submodules SM1 to SM2 connected in sequence. N Where N≥2; The energy storage submodule adopts the three-terminal two-switch energy storage submodule as described in any one of claims 1 to 7; Adjacent energy storage submodules are cascaded according to a preset port connection relationship, wherein the second split end and the common connection end of adjacent energy storage submodules are connected to form a cascaded energy storage structure; the energy storage submodules at both ends of the cascaded energy storage structure are respectively connected to the stimulation coil.

9. The transcranial magnetic stimulation circuit according to claim 8, characterized in that, Adjacent energy storage submodules are connected by fixed ports. The energy storage submodules do not have active reconfiguration switches inside them to change the electrical connection between the first split end, the second split end, and the common connection end. The port connection between each energy storage submodule and the connection between the energy storage submodule and the energy storage node of the adjacent energy storage submodule remain fixed during operation.

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