Dual load inverter module and inverter system

Abstract

The application relates to a dual-load inverter module and an inverter system. The dual-load inverter module comprises three bridge arms and a control module, wherein the bridge arm has a first end and a second end, and a first half-bridge and a second half-bridge are connected in series between the first end and the second end; the on-off state of the first half-bridge of any bridge arm is opposite to that of the second half-bridge on the bridge arm, so that the dual-load inverter module will not be in a straight-through short circuit state at any moment. The dual-load inverter module provides a circuit for independently controlling two polar field coils based on the three bridge arms, so that the cost is greatly reduced.

Description

Technical Field

[0001] This application relates to the field of inverter technology, and in particular to a dual-load inverter module and inverter system. Background Technology

[0002] In magnetically confined nuclear fusion devices, the power supply system of the poloidal field coils is a crucial component for generating, maintaining, and controlling plasma configuration and current. Advanced tokamak devices, exemplified by ITER (International Thermonuclear Experimental Reactor), typically have poloidal field power systems with rated capacities exceeding 300 MVA. This system, characterized by high pulsed power and fast dynamic response, is a core subsystem ensuring the safe and stable operation of the tokamak device. However, the electrical requirements of the main coils in this system remain physically coupled, preventing cost reduction while ensuring independent control of multiple coils. Summary of the Invention

[0003] Therefore, it is necessary to provide a low-cost dual-load inverter module and inverter system that can independently control multiple poloidal field coils.

[0004] A dual-load inverter module, used in a magnetic confinement nuclear fusion device, includes: three bridge arms, a poloidal field coil, and a control module;

[0005] The bridge arm has a first end and a second end, and a first half-bridge and a second half-bridge connected in series between the first end and the second end. The first end of the bridge arm is used to connect to the positive terminal of the DC bus, and the second end of the bridge arm is used to connect to the negative terminal of the DC bus.

[0006] The poloidal field coil is connected across the middle connection point of two adjacent bridge arms. The middle connection point is the connection point between the first half-bridge and the second half-bridge of the bridge arm.

[0007] The control module is connected to the first half-bridge and the second half-bridge of each bridge arm respectively; the control module is used to control the on / off state of each first half-bridge and each second half-bridge.

[0008] In one bridge arm, the on / off state of the first half-bridge is opposite to that of the second half-bridge.

[0009] In one embodiment, the first half-bridge includes:

[0010] The first switching circuit has a first terminal for connecting to the positive terminal of the DC bus, a second terminal for connecting to the poloidal field coil, and a third terminal for connecting to the first control terminal of the control module. The first switching circuit is used to receive the first conduction signal from the control module so that the current of the DC bus flows from the first terminal of the first switching circuit to the second terminal of the first switching circuit.

[0011] The first reverse freewheeling circuit is connected in reverse parallel with the first switching circuit.

[0012] The second half of the bridge includes:

[0013] The second switching circuit has its first terminal connected to the second terminal of the first switching circuit and the poloidal field coil, respectively. The second terminal of the second switching circuit is used to connect to the negative terminal of the DC bus, and the third terminal of the second switching circuit is connected to the second control terminal of the control module. The second switching circuit is used to receive the second conduction signal of the control module so that the current of the DC bus flows from the first terminal of the second switching circuit to the second terminal of the second switching circuit.

[0014] The second reverse freewheeling circuit is connected in parallel with the second switching circuit in reverse.

[0015] In one embodiment, the three bridge arms include a first bridge arm, a second bridge arm, and a third bridge arm, and the poloidal field coil includes a first poloidal field coil and a second poloidal field coil.

[0016] The first poloidal field coil is connected between the middle connection point of the first bridge arm and the middle connection point of the second bridge arm, and the second poloidal field coil is connected between the middle connection point of the second bridge arm and the middle connection point of the third bridge arm.

[0017] In one embodiment, the first switching circuit includes at least one first switching transistor, and the first reverse freewheeling circuit is a first diode;

[0018] The second switching circuit includes at least one second switching transistor, and the second reverse freewheeling circuit is a second diode.

[0019] In one embodiment, the control module is configured to output a first turn-on signal or a second turn-on signal, wherein the first turn-on signal is used to turn on the first switch of the second bridge arm, and the second turn-on signal is used to turn on the second switch of the second bridge arm.

[0020] In one embodiment, the first switching transistor is a first insulated gate bipolar transistor (IGBT), the collector of the IGBT is used to connect to the positive terminal of the DC bus, the emitter of the IGBT is connected to the poloidal field coil, and the gate of the IGBT is connected to the first control terminal of the control module.

[0021] The second switching transistor is a second insulated-gate bipolar transistor. The collector of the second insulated-gate bipolar transistor is connected to the second terminal of the first switching circuit and the poloidal field coil, respectively. The emitter of the second insulated-gate bipolar transistor is used to connect to the negative terminal of the DC bus. The gate of the second insulated-gate bipolar transistor is connected to the second control terminal of the control module.

[0022] In one embodiment, the first switching transistor is a first integrated gate commutated thyristor, the anode of the first integrated gate commutated thyristor is used to connect to the positive terminal of the DC bus, the cathode of the first integrated gate commutated thyristor is connected to the poloidal field coil, and the gate of the first integrated gate commutated thyristor is connected to the first control terminal of the control module.

[0023] The second switching transistor is a second integrated gate commutated thyristor. The anode of the second integrated gate commutated thyristor is connected to the second terminal of the first switching circuit and the poloidal field coil, respectively. The cathode of the second integrated gate commutated thyristor is used to connect to the negative terminal of the DC bus. The gate of the second integrated gate commutated thyristor is connected to the second control terminal of the control module.

[0024] In one embodiment, the first switching transistor is a first field-effect transistor, and the gate of the first field-effect transistor is connected to the first control terminal of the control module;

[0025] The second switch is a second field-effect transistor, and the gate of the second field-effect transistor is connected to the second control terminal of the control module.

[0026] In one embodiment, the dual-load inverter module further includes:

[0027] The protection module is connected to the first half-bridge and the second half-bridge of each bridge arm respectively. The protection module is used to disconnect the first half-bridge and the second half-bridge of each bridge arm in the event of a fault.

[0028] Secondly, an inverter system is also provided, including multiple dual-load inverter modules as described above, wherein each dual-load inverter module is connected in parallel and / or cascaded.

[0029] The aforementioned dual-load inverter module and inverter system include a dual-load inverter module comprising three bridge arms and a control module. Each bridge arm has a first end and a second end, and a first half-bridge and a second half-bridge connected in series between the first end and the second end. The on / off state of the first half-bridge of any bridge arm is opposite to the on / off state of the second half-bridge on that bridge arm. Therefore, the dual-load inverter module ensures that no bridge arm will experience a shoot-through or short circuit at any given time. This dual-load inverter module provides a circuit based on three bridge arms for independent control of two poloidal field coils, thereby significantly reducing costs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is one of the structural block diagrams of a dual-load inverter module according to an embodiment;

[0032] Figure 2 This is a second structural block diagram of a dual-load inverter module according to one embodiment;

[0033] Figure 3 This is one of the schematic diagrams showing the current flow of a dual-load inverter module according to an embodiment;

[0034] Figure 4 This is a second schematic diagram of the current flow direction of a dual-load inverter module according to one embodiment;

[0035] Figure 5 This is a block diagram of an inverter system according to one embodiment. Detailed Implementation

[0036] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0038] It is understood that the terms "first," "second," etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first half-bridge may be referred to as a second half-bridge, and similarly, a second half-bridge may be referred to as a first half-bridge. Both the first and second half-bridges are half-bridges, but they are not the same half-bridge.

[0039] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0040] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0041] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0042] Currently, the power supply system for poloidal field coils mainly adopts a single-coil independent power supply topology or a combined power supply topology based on the operating requirements of symmetrical coils.

[0043] In the single-coil independent power supply topology, each poloidal coil is powered by an independent power source, and all power sources converge on the AC side. This topology offers flexible control, but systems using it have a large total installed capacity. Most systems employing this topology utilize thyristor-controlled phase-controlled rectifiers without energy storage, offering advantages such as mature technology and high reliability. However, they suffer from inherent drawbacks such as low system power factor, high grid-side harmonic content, and poor power quality. More critically, due to the lack of energy storage, systems using this topology are susceptible to voltage loss in the event of grid fluctuations or short-term faults, potentially leading to interruptions in discharge experiments and damage to critical components. Furthermore, adopting a fully controlled device rectifier-DC bus-single-phase inverter architecture as an improvement to the above system has advantages such as high power factor, fast dynamic response, and good power quality. Moreover, its DC bus is easy to integrate energy storage modules to smooth grid fluctuations and reduce the coupling strength with the grid. However, there are still significant problems: each coil in this scheme needs to be equipped with an independent four-quadrant full-bridge inverter, which will increase the number of high-power fully controlled semiconductor devices required, resulting in high equipment costs and large operating losses. In addition, the high-current fully controlled technology is not yet fully mature.

[0044] In joint power supply topologies based on the operational requirements of symmetrical coils, a typical example is the vertically stabilized rectifier group scheme adopted by the ITER and EU-DEMO (European Demonstration Fusion Power Plant) devices. This scheme utilizes the similar current requirements of the spatially symmetrically distributed poloidal coils, establishing direct electrical connections between the poloidal coils and employing a smaller capacity, higher voltage common converter to improve plasma vertical stability. While maintaining equivalent control performance, this scheme also reduces the total installed capacity of the power system. In this scheme, due to the smaller current parameters, the common converter is more likely to adopt fully controlled inverter technology and achieve a higher dynamic response speed. However, although this scheme integrates the power supply of symmetrical coils at the system level, it does not fundamentally solve the common problems of high cost and high losses associated with fully controlled power supplies in poloidal field applications. In fact, in the vertically stabilized rectifier group scheme adopted by the ITER device, the converter modules supplying power to each series-connected coil still use the traditional thyristor rectifier architecture, rather than fully controlled inverters.

[0045] In-depth analysis of the operating characteristics of the tokamak poloidal field system reveals that the electrical requirements of the main coils (such as the central solenoid coil and the weak-field side balance field coil) are physically coupled. However, existing power supply schemes fail to fully utilize this power coupling potential.

[0046] Therefore, it can be seen that the existing power supply schemes for poloidal field coils, whether traditional thyristor phase-controlled rectification schemes or independent power supply schemes based on full-bridge or their improved combined power supply schemes, are all difficult to achieve an ideal balance between technological advancement, engineering economy and operational efficiency.

[0047] In a specific embodiment, such as Figure 1 As shown, a dual-load inverter module 10 is provided, including: three bridge arms 110 and a control module ( Figure 1 (Not shown).

[0048] The bridge arm 110 has a first end and a second end, and a first half-bridge 112 and a second half-bridge 114 connected in series between the first end and the second end. The first end of the bridge arm 110 is used to connect to the positive terminal of the DC bus, and the second end of the bridge arm 110 is used to connect to the negative terminal of the DC bus.

[0049] The poloidal field coil 140 is connected across the middle connection point of two adjacent bridge arms 110. The middle connection point is the connection point of the first half-bridge 112 and the second half-bridge 114 of the bridge arm 110.

[0050] The control module is connected to the first half-bridge 112 and the second half-bridge 114 of each bridge arm 110 respectively; the control module is used to control the on / off state of each first half-bridge 112 and each second half-bridge 114.

[0051] In one of the bridge arms 110, the on / off state of the first half-bridge 112 is opposite to that of the second half-bridge 114.

[0052] The dual-load inverter module 10 has two DC ports. One DC port is the port after the first ends of the first half-bridge 112 of each bridge arm 110 are connected at a common point, and is used to connect to the positive terminal of the DC bus. The other DC port is the port after the first ends of the second half-bridge 114 of each bridge arm 110 are connected at a common point, and is used to connect to the negative terminal of the DC bus. The dual-load inverter module 10 has three AC load ports, which are the ports for connecting the two poloidal field coils 140.

[0053] It should be noted that the poloidal field coil 140 bridging the intermediate connection point of two adjacent bridge arms 110 can be understood as the dual-load inverter module 10 including two poloidal field coils 140. Specifically, a poloidal field coil 140 is connected in series between the intermediate connection points of the two bridge arms 110, and another poloidal field coil 140 is connected in series between the intermediate connection point of the bridge arm 110 with the poloidal field coil 140 not connected in series. In one embodiment, the poloidal field coil 140 can be the poloidal field coil 140 of a tokamak device. Specifically, one of the poloidal field coils 140 can be a central solenoid coil, and the other poloidal field coil 140 can be a balanced field coil located on the weak field side.

[0054] In one bridge arm 110, the on / off state of the first half-bridge 112 is opposite to that of the second half-bridge 114. This can be understood as follows: at any given moment, if the first half-bridge 112 of a bridge arm 110 is in a conducting state, then the second half-bridge 114 of that bridge arm 110 is in a disconnected state; conversely, if the first half-bridge 112 of a bridge arm 110 is in a disconnected state, then the second half-bridge 114 of that bridge arm 110 is in a conducting state. Therefore, at any given moment, neither bridge arm 110 will experience a shoot-through short circuit, thereby improving the circuit reliability of the dual-load inverter module 10.

[0055] Since the control module can independently control the on / off state of the first half-bridge 112 and the second half-bridge 114 of the three bridge arms 110, it can independently control the voltage applied across the two poloidal field coils 140, thereby achieving four-quadrant operation of the two poloidal field coils 140. This four-quadrant operation includes independent positive and negative changes in voltage polarity and independent positive and negative changes in current polarity. Therefore, under long-term steady-state conditions, the dual-load inverter module 10 can simultaneously provide the required voltage to both poloidal field coils 140; when a sudden surge in voltage demand occurs in one of the poloidal field coils 140, the dual-load inverter module 10 can prioritize the output voltage to that poloidal field coil 140, thus satisfying its transient demand.

[0056] Furthermore, compared to traditional inverter modules with four bridge arms (including two independent H-bridges), this dual-load inverter module 10 adopts a three-bridge-arm topology, thereby achieving independent control of the two poloidal field coils 140 with three bridge arms 110. As a result, this dual-load inverter module 10 significantly reduces the number of required components and / or modules, thereby greatly reducing hardware costs, size, and losses.

[0057] The aforementioned dual-load inverter module 10 includes three bridge arms 110 and a control module. Each bridge arm 110 has a first end and a second end, and a first half-bridge 112 and a second half-bridge 114 connected in series between the first end and the second end. The on / off state of the first half-bridge 112 of any bridge arm 110 is opposite to the on / off state of the second half-bridge 114 on that bridge arm 110. Therefore, the dual-load inverter module 10 ensures that no bridge arm 110 will experience a shoot-through or short circuit at any time. This dual-load inverter module 10 provides a circuit for independently controlling two poloidal field coils 140 based on three bridge arms 110, thereby significantly reducing costs.

[0058] In a specific embodiment, such as Figure 2 As shown, the first half-bridge 112 includes: a first switching circuit and a first reverse freewheeling circuit.

[0059] The first terminal of the first switching circuit is used to connect to the positive terminal of the DC bus, the second terminal of the first switching circuit is connected to the poloidal field coil 140, and the third terminal of the first switching circuit is connected to the first control terminal of the control module. The first switching circuit is used to receive the first conduction signal of the control module so that the current of the DC bus flows from the first terminal of the first switching circuit to the second terminal of the first switching circuit.

[0060] The first reverse freewheeling circuit is connected in reverse parallel with the first switching circuit.

[0061] The second half-bridge 114 includes: a second switching circuit and a second reverse freewheeling circuit.

[0062] The first terminal of the second switching circuit is connected to the second terminal of the first switching circuit and the poloidal field coil 140, respectively. The second terminal of the second switching circuit is used to connect to the negative terminal of the DC bus. The third terminal of the second switching circuit is connected to the second control terminal of the control module. The second switching circuit is used to receive the second conduction signal of the control module so that the current of the DC bus flows from the first terminal of the second switching circuit to the second terminal of the second switching circuit.

[0063] The second reverse freewheeling circuit is connected in reverse parallel with the second switching circuit.

[0064] Taking one bridge arm 110 as an example, when the first switching circuit of bridge arm 110 receives the first conduction signal output by the control module, the first switching circuit of bridge arm 110 is turned on; when the first switching circuit of bridge arm 110 does not receive the first conduction signal output by the control module, the first switching circuit of bridge arm 110 is turned off, and at this time, current flows into the second switching circuit of bridge arm 110. The voltage polarity when the first switching circuit is turned on is opposite to the voltage polarity when current flows into the second switching circuit. Here, voltage polarity refers to the voltage polarity of the poloidal field coil 140.

[0065] It should be noted that when the first switching circuit of bridge arm 110 receives the first shutdown signal output by the control module, the first switching circuit of bridge arm 110 can also be disconnected. Similarly, when the second switching circuit of bridge arm 110 receives the second shutdown signal output by the control module, the second switching circuit of bridge arm 110 can also be disconnected.

[0066] The current flow direction on the first half-bridge 112 is related to the current polarity of the pole field coil 140. Specifically, when the first switching circuit of the first half-bridge 112 is turned on and the current flows from the first terminal of the first switching circuit to the second terminal of the first switching circuit, the current flowing into the pole field coil 140 is a positive current, and the current polarity of the pole field coil 140 is positive. When the first reverse freewheeling circuit of the first half-bridge 112 is turned on and the current flows from the pole field coil 140 to the first reverse freewheeling circuit and then to the positive terminal of the DC bus, the current flowing into the pole field coil 140 is a negative current, and the current polarity of the pole field coil 140 is negative.

[0067] Similarly, the current flow direction on the second half-bridge 114 is related to the current polarity of the pole-field coil 140. Specifically, when the second switching circuit of the second half-bridge 114 is turned on and the current flows from the second terminal of the second switching circuit to the first terminal of the second switching circuit, the current flowing into the pole-field coil 140 is a positive current, and the current polarity of the pole-field coil 140 is positive. When the second reverse freewheeling circuit of the second half-bridge 114 is turned on and the current flows from the negative terminal of the DC bus to the second reverse freewheeling circuit and then to the pole-field coil 140, the current flowing into the pole-field coil 140 is a negative current, and the current polarity of the pole-field coil 140 is negative.

[0068] In a specific embodiment, such as Figure 1 As shown, the three bridge arms 110 include a first bridge arm, a second bridge arm, and a third bridge arm, and the poloidal field coils include a first poloidal field coil and a second poloidal field coil.

[0069] The first poloidal field coil is connected between the middle connection point of the first bridge arm and the middle connection point of the second bridge arm, and the second poloidal field coil is connected between the middle connection point of the second bridge arm and the middle connection point of the third bridge arm.

[0070] The first poloidal field coil is turned on when the first half-bridge 112 of the first bridge arm and the second half-bridge 114 of the second bridge arm are both turned on, or when the first half-bridge 112 of the first bridge arm and the first half-bridge 112 of the second bridge arm are both turned on, or when the second half-bridge 114 of the first bridge arm and the first half-bridge 112 of the second bridge arm are both turned on.

[0071] The second pole-direction field coil is turned on when the first half-bridge 112 of the second bridge arm and the second half-bridge 114 of the third bridge arm are both turned on, or when the first half-bridge 112 of the second bridge arm and the first half-bridge 112 of the third bridge arm are both turned on, or when the second half-bridge 114 of the second bridge arm and the first half-bridge 112 of the third bridge arm are both turned on.

[0072] In one specific embodiment, the first switching circuit includes at least one first switching transistor, and the first reverse freewheeling circuit is a first diode.

[0073] The second switching circuit includes at least one second switching transistor, and the second reverse freewheeling circuit is a second diode.

[0074] The number of first switching transistors in the first switching circuit can be determined according to the preset current carrying capacity of the bridge arm in which the first switching circuit is located, and the first switching transistors are connected in parallel. Similarly, the number of second switching transistors in the second switching circuit can be determined according to the preset current carrying capacity of the bridge arm in which the second switching circuit is located, and the second switching transistors are connected in parallel.

[0075] For example, such as Figure 2As shown, the first switching circuit in the first bridge arm includes a first switching transistor S11, and the first reverse freewheeling circuit in the first bridge arm is a first diode D11. The second switching circuit in the first bridge arm includes a second switching transistor S12, and the second reverse freewheeling circuit in the first bridge arm is a second diode D12. The first switching circuit in the second bridge arm includes a first switching transistor S11, and the first reverse freewheeling circuit in the second bridge arm is a first diode D11. The second switching circuit in the second bridge arm includes a second switching transistor S12, and the second reverse freewheeling circuit in the second bridge arm is a second diode D12. The first switching circuit in the third bridge arm includes a first switching transistor S11, and the first reverse freewheeling circuit in the third bridge arm is a first diode D11. The second switching circuit in the third bridge arm includes a second switching transistor S12, and the second reverse freewheeling circuit in the third bridge arm is a second diode D12.

[0076] The voltage polarity across the first poloidal field coil is determined by the potential difference between the first switch S11 of the first bridge arm and the first switch S11 of the second bridge arm. Similarly, the voltage polarity across the second poloidal field coil is determined by the potential difference between the first switch S11 of the second bridge arm and the first switch S11 of the third bridge arm. The control module controls the voltage polarity across the first and second poloidal field coils by controlling the first switch S11, the second switch S12 of the first bridge arm, the first switch S11 of the second bridge arm, the second switch S12 of the second bridge arm, the first switch S11 of the third bridge arm, and the second switch S12 of the third bridge arm. The voltage polarity across the poloidal field coils can be positive, zero, or negative.

[0077] Turning on the first switch S11 of the first bridge arm and the second switch S12 of the second bridge arm, and ensuring that the current flowing through the first pole-field coil is greater than 0 (i.e., current flows from port A to port B), will establish a positive voltage across the first pole-field coil. At this time, the first pole-field coil exhibits a state of positive voltage and positive current.

[0078] The current flowing through the first polefactory coil is less than 0, meaning the current flows from port B to port A, and the current also flows through the first diode D11 of the first bridge arm and the second diode D12 of the second bridge arm. A positive voltage will also be established across the first polefactory coil. At this time, the first polefactory coil presents a state of positive voltage and negative current.

[0079] The first switch S11 of the first bridge arm and the first switch S11 of the second bridge arm are turned on, so that ports A and B are shorted to the same potential, providing a freewheeling path for the current in the pole-field coil. At this time, the voltage across the first pole-field coil is close to zero, thus the first pole-field coil presents a zero-voltage state. At this time, if the current flows through the first switch S11 of the first bridge arm and the first diode D11 of the second bridge arm, that is, the current flows from port A to port B, then the current flowing through the first pole-field coil is a positive current; if the current flows through the first switch S11 of the second bridge arm and the first diode D11 of the first bridge arm, that is, the current flows from port B to port A, then the current flowing through the first pole-field coil is a negative current.

[0080] Similarly, turning on the second switching transistors S12 of the first and second bridge arms can short-circuit ports A and B to the same potential, providing a freewheeling path for the current in the pole-field coil. At this time, the voltage across the first pole-field coil is close to zero, thus the first pole-field coil exhibits a zero-voltage state. If current flows through the second diode D12 of the first bridge arm and the second switching transistor S12 of the second bridge arm (i.e., current flows from port A to port B), the current flowing through the first pole-field coil is positive. If current flows through the second diode D12 of the second bridge arm and the second switching transistor S12 of the first bridge arm (i.e., current flows from port B to port A), the current flowing through the first pole-field coil is negative.

[0081] Turning on the second switch S12 of the first bridge arm and the first switch S11 of the second bridge arm, and ensuring that the current flowing through the first pole-field coil is greater than 0 (i.e., current flows from port B to port A), will establish a positive voltage across the first pole-field coil. At this time, the first pole-field coil exhibits a state of negative voltage and positive current.

[0082] The current flowing through the first pole-field coil is less than 0, meaning the current flows from port A to port B, and the current also flows through the second diode D12 of the first bridge arm and the first diode D11 of the second bridge arm. A negative voltage will also be established across the first pole-field coil. At this time, the first pole-field coil exhibits a state of negative voltage and negative current.

[0083] The control of the voltage and current states presented by the second pole-field coil can be referenced to the control of the voltage and current states presented by the first pole-field coil, and will not be repeated here. Therefore, by controlling the voltage and circuit states of the first and second pole-field coils separately, the four-quadrant operation requirements of both coils can be met. Specifically, in terms of control, if the current flowing through the first pole-field coil is flowing into the first switch S11 of the first bridge arm, then when the first switch S11 of the first bridge arm is turned off, the current can be forced to commutate to the second diode D12 of the first bridge arm, thereby achieving voltage polarity control of the first pole-field coil. The control module output to the switch can be a modulated wave or other types of switching signals.

[0084] Therefore, the basic switching combination corresponding to the specific voltage polarity applied to the first and second poloidal field coils is determined. The current path flowing through the first and second poloidal field coils will automatically select whether to flow through the switching transistor or the diode according to the current direction, realizing bidirectional energy flow.

[0085] It should be noted that when the current in the first pole-field coil is negative, i.e., the current flows from port B to port A, if a positive voltage needs to be applied to the first pole-field coil, the current needs to flow through the first diode D11 of the first bridge arm and the second diode D12 of the second bridge arm. In this case, the low-impedance reverse freewheeling path provided by the first diode D11 of the first bridge arm and the second diode D12 of the second bridge arm is required. This is because a unidirectional conducting switch can only conduct in reverse under a very high reverse voltage drop, i.e., the switch will break down or be damaged. To reduce the losses of the switch and protect the unidirectional conducting switch, and also to provide a low-impedance current freewheeling path under a certain pole-field coil voltage polarity, diodes are needed.

[0086] Furthermore, if a bidirectional switching transistor is used, a reverse diode will also be required in parallel in actual use. This is to provide a freewheeling path for the poloidal field coil when both the first and second switching transistors in the same bridge arm are turned off.

[0087] In one specific embodiment, the control module is used to turn on the first switch S11 of the second bridge arm, or to turn on the second switch S12 of the second bridge arm.

[0088] See Figure 3 and Figure 4When both the first and second field-directing coils have positive currents, the current in the first half-bridge 112 of the second bridge arm is the difference between the currents in the first and second field-directing coils. Therefore, within the first half-bridge 112 of the second bridge arm, the distribution of current flowing through the first and second field-directing coils needs to be considered. The currents flowing through the first and second field-directing coils have already converged before flowing through any device within the first half-bridge 112 of the second bridge arm. Specifically, if the current flowing through the first field-directing coil is greater than the current flowing through the second field-directing coil, then the total current in the first half-bridge 112 of the second bridge arm will flow through the first diode D11 of the second bridge arm; conversely, if the current flowing through the first field-directing coil is less than the current flowing through the second field-directing coil, then the total current in the first half-bridge 112 of the second bridge arm will flow through the first switching transistor S11 of the second bridge arm. In practice, the control module can apply a corresponding turn-on signal to the first switch S11 of the second bridge arm, but not to the second switch S12 of the second bridge arm. Then, regardless of the relationship between the current value flowing through the first pole-field coil and the current value flowing through the second pole-field coil, the total current will flow through the first switch S11 or the first diode D11 of the second bridge arm.

[0089] The above response corresponds to one switching state of the dual-load inverter module 10. In all switching states, when a negative voltage is applied to the first pole-field coil, a positive voltage or zero voltage is generally applied to the second pole-field coil, which is the original design intention. Specifically, the dual-load inverter module 10 can multiplex the two pole-field coils through a voltage source, without the need for two H-bridges (traditional solution). Thus, when the first pole-field coil requires a large voltage output (such as a positive voltage), the second pole-field coil mainly operates in a freewheeling state (zero voltage).

[0090] It should be noted that the voltage output of the second poloidal field coil is not uncontrollable. Even with the constraint that the on / off states of the first half-bridge of the target bridge arm are opposite to those of the second half-bridge (i.e., neither bridge arm can be directly connected), the second poloidal field coil can still output the maximum negative voltage. Although this dual-load inverter module 10 cannot simultaneously supply large voltage values ​​of the same polarity to both poloidal field coils, the high voltage demand periods for the two specific superconducting magnet poloidal field coils of the tokamak are significantly separated. This demonstrates the reuse of the required voltage capacity for the two poloidal field coils by the dual-load inverter module 10. Compared to this dual-load inverter module 10, using two independent H-bridges to supply power to the two poloidal field coils separately (the traditional solution) would require 1 / 3 more switching transistors. Therefore, this dual-load inverter module 10 significantly reduces the installed capacity for superconducting magnet poloidal field coils with extremely high current parameters (tens of kiloamperes). Furthermore, the dual-load inverter module 10 can simultaneously provide a large positive voltage to the first poloidal field coil and a large negative voltage to the second poloidal field coil, which is more in line with the operating conditions of the superconducting magnets in the tokamak.

[0091] Compared to two independent H-bridges (traditional solution), the additional constraint of this dual-load inverter module 10 is that it cannot output large voltages of the same polarity simultaneously, which can be expressed by the formula U1+U2≤U, where U1 is the voltage provided to the first pole field coil, U2 is the voltage provided to the second pole field coil, and U is the constant voltage on the DC side.

[0092] In one specific embodiment, the first switching transistor is a first insulated gate bipolar transistor (IGBT). The collector of the IGBT is used to connect to the positive terminal of the DC bus, the emitter of the IGBT is connected to the poloidal field coil, and the gate of the IGBT is connected to the first control terminal of the control module.

[0093] The second switching transistor is a second insulated-gate bipolar transistor. The collector of the second insulated-gate bipolar transistor is connected to the second terminal of the first switching circuit and the poloidal field coil, respectively. The emitter of the second insulated-gate bipolar transistor is used to connect to the negative terminal of the DC bus. The gate of the second insulated-gate bipolar transistor is connected to the second control terminal of the control module.

[0094] Insulated-gate bipolar transistors (IGBTs) offer the advantage of wide voltage and current coverage, enabling full coverage from medium-high voltage to high power, making them the most versatile. IGBTs are voltage-driven, resulting in low driving difficulty and mature, reliable driving circuits. Furthermore, IGBTs balance switching speed and losses, thus achieving a balance between efficiency and dynamic performance. Therefore, IGBTs are suitable for four-quadrant operation of the poloidal field coils in pulsed conditions, medium-high voltage, and medium-high power inverters, and are also suitable for medium-high voltage and medium-high power inverter scenarios.

[0095] In one specific embodiment, the first switching transistor is a first integrated gate commutated thyristor. The anode of the first integrated gate commutated thyristor is used to connect to the positive terminal of the DC bus, the cathode of the first integrated gate commutated thyristor is connected to the poloidal field coil, and the gate of the first integrated gate commutated thyristor is connected to the first control terminal of the control module.

[0096] The second switching transistor is a second integrated gate commutated thyristor. The anode of the second integrated gate commutated thyristor is connected to the second terminal of the first switching circuit and the poloidal field coil, respectively. The cathode of the second integrated gate commutated thyristor is used to connect to the negative terminal of the DC bus. The gate of the second integrated gate commutated thyristor is connected to the second control terminal of the control module.

[0097] Integrated gate-commutated thyristors (ICTs) exhibit extremely low on-state voltage drop and conduction losses lower than those of insulated-gate bipolar transistors (IGBTs) and field-effect transistors (FETs), resulting in significant efficiency advantages at ultra-high power levels. Furthermore, ICTs possess strong current capacity and surge current capability, enabling them to withstand the ultra-large pulse currents characteristic of fusion power supplies. ICTs also boast exceptional short-circuit and overcurrent withstand capabilities, ensuring extremely high reliability and suitability for demanding high-power applications. Therefore, ICTs are suitable for ultra-high voltage, ultra-high power, low-frequency inverter, and low-frequency converter applications.

[0098] In one specific embodiment, the first switching transistor is a first field-effect transistor, and the gate of the first field-effect transistor is connected to the first control terminal of the control module.

[0099] The second switch is a second field-effect transistor, and the gate of the second field-effect transistor is connected to the second control terminal of the control module.

[0100] Field-effect transistors (FETs) offer fast switching speeds and low switching losses, making them particularly suitable for high-frequency inversion. FETs are purely voltage-driven, requiring low drive power and simple drive circuitry. Furthermore, they exhibit low on-resistance and high efficiency under low voltage and high current conditions. Therefore, FETs are suitable for low-voltage, high-frequency, and low-to-medium power inverter applications.

[0101] It should be noted that field-effect transistors are bidirectional conductive devices. Taking the first switching transistor as the first field-effect transistor as an example, when the current flowing through the first terminal to the field coil is negative and the first switching transistor S11 of the first bridge arm is given a corresponding turn-on signal by the control module, part of the current may return to the positive terminal of the DC bus through the first switching transistor S11 of the first bridge arm, and part of the current may also return to the positive terminal of the DC bus through the first diode D11 of the first bridge arm.

[0102] In one embodiment, the first diode is a power diode; the second diode is a power diode.

[0103] In one specific embodiment, the dual-load inverter module 10 further includes a protection module.

[0104] The protection module is connected to the first half-bridge and the second half-bridge of each bridge arm respectively. The protection module is used to disconnect the first half-bridge and the second half-bridge of each bridge arm in the event of a fault.

[0105] The protection module is also used to monitor the voltage of the DC bus, the current of each bridge arm, and the switching status of the first and second switches of each bridge arm in real time. When a fault such as overcurrent, overvoltage, or short circuit is detected, the first and second half-bridges of each bridge arm are disconnected, that is, the first and second switches of each bridge arm are disconnected, to ensure the safety of the dual-load inverter module 10.

[0106] Compared with the existing traditional scheme of configuring a dual-arm full-bridge (H-bridge) inverter for each poloidal coil independently, the dual-load inverter module 10 of this application, with its three-arm shared topology and voltage multiplexing mechanism, has the following significant advantages while achieving independent, high-performance control of the two poloidal coils:

[0107] First, by using three bridge arms instead of the four bridge arms in the traditional solution, approximately 25% of the power semiconductor devices and their associated drive and protection circuits are reduced, resulting in a significant decrease in hardware cost, size, and power consumption.

[0108] Second, during the normal evolution phase of plasma (such as the current ramp-up phase, the flat-top phase, and the descent phase), the topology of this dual-load inverter module 10, through sharing a DC bus, can efficiently provide the required equal voltage of the same polarity to both poloidal field coils, achieving coordinated utilization of the bus voltage. When an unexpected transient event occurs in the plasma, and a poloidal field coil requires instantaneous full voltage, the topology of this dual-load inverter module 10 can, through the coordinated modulation of the bridge arms, "multiplex" the DC bus voltage and concentrate it on the poloidal field coil, thereby achieving the transient high-voltage output capability that traditionally requires two independent modules with a single module.

[0109] Third: This "one source, two uses" voltage reuse mechanism makes the dual-load inverter module 10 more adaptable to the specific operating conditions of the tokamak poloidal field coil (especially the scenario where steady state and transient state alternate), overcoming the shortcomings of traditional solutions in terms of structural redundancy, low device utilization and poor control coordination.

[0110] Fourth: Compared to the single-coil poloidal field power supply design, the dual-load inverter module 10 joint power supply design establishes a direct electrical connection between the poloidal field coils. By sharing a DC bus, the pulse power flow between the joint poloidal field coils cancels each other out in a more compact electrical architecture, thus significantly reducing the capacity of a single energy storage module.

[0111] In a specific embodiment, such as Figure 5 As shown, an inverter system 1 includes multiple dual-load inverter modules 10 as described above, with each dual-load inverter module 10 connected in parallel and / or cascaded.

[0112] Multiple dual-load inverter modules 10 can be connected in parallel to meet the current requirements of the poloidal field coil; multiple dual-load inverter modules can also be cascaded with each other or with other types of dual-load inverter modules (such as standard H-bridge modules) to form a multi-level inverter, improve the output voltage level, and adapt to poloidal field coil systems with diverse voltage requirements.

[0113] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0114] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A dual load inverter module, characterized by, It is used in magnetic confinement nuclear fusion devices and includes: three bridge arms, a poloidal field coil, and a control module; The bridge arm has a first end and a second end, and a first half-bridge and a second half-bridge connected in series between the first end and the second end. The first end of the bridge arm is used to connect to the positive terminal of the DC bus, and the second end of the bridge arm is used to connect to the negative terminal of the DC bus. The poloidal field coil is connected across the middle connection point of two adjacent bridge arms, and the middle connection point is the connection point of the first half-bridge and the second half-bridge of the bridge arm. The control module is connected to the first half-bridge and the second half-bridge of each of the bridge arms respectively; the control module is used to control the on / off state of each first half-bridge and each second half-bridge. In one of the bridge arms, the on / off state of the first half-bridge is opposite to that of the second half-bridge; The first half-bridge includes: A first switching circuit, wherein a first terminal of the first switching circuit is used to connect to the positive terminal of the DC bus, a second terminal of the first switching circuit is connected to the poloidal field coil, and a third terminal of the first switching circuit is connected to the first control terminal of the control module; the first switching circuit is used to receive a first conduction signal from the control module so that the current of the DC bus flows from the first terminal of the first switching circuit to the second terminal of the first switching circuit. The first reverse freewheeling circuit is connected in reverse parallel with the first switching circuit. The second half-bridge includes: The second switching circuit has a first terminal connected to the second terminal of the first switching circuit and the poloidal field coil, a second terminal connected to the negative terminal of the DC bus, and a third terminal connected to the second control terminal of the control module. The second switching circuit is used to receive the second conduction signal of the control module so that the current of the DC bus flows from the first terminal to the second terminal of the second switching circuit. The second reverse freewheeling circuit is connected in reverse parallel with the second switching circuit. The three bridge arms include a first bridge arm, a second bridge arm, and a third bridge arm, and the poloidal field coil includes a first poloidal field coil and a second poloidal field coil; The first poloidal field coil is connected between the middle connection point of the first bridge arm and the middle connection point of the second bridge arm, and the second poloidal field coil is connected between the middle connection point of the second bridge arm and the middle connection point of the third bridge arm.

2. The dual load inverter module of claim 1, wherein, The first switching circuit includes at least one first switching transistor, and the first reverse freewheeling circuit is a first diode; The second switching circuit includes at least one second switching transistor, and the second reverse freewheeling circuit is a second diode.

3. The dual load inverter module of claim 2, wherein, The control module is used to turn on the first switch of the second bridge arm, or to turn on the second switch of the second bridge arm.

4. The dual load inverter module of claim 2, wherein, The first switching transistor is a first insulated gate bipolar transistor (IGBT). The collector of the first IGBT is used to connect to the positive terminal of the DC bus. The emitter of the first IGBT is connected to the poloidal field coil. The gate of the first IGBT is connected to the first control terminal of the control module. The second switching transistor is a second insulated gate bipolar transistor. The collector of the second insulated gate bipolar transistor is connected to the second terminal of the first switching circuit and the poloidal field coil, respectively. The emitter of the second insulated gate bipolar transistor is used to connect to the negative terminal of the DC bus, and the gate of the second insulated gate bipolar transistor is connected to the second control terminal of the control module.

5. The dual-load inverter module according to claim 2, characterized in that, The first switching transistor is a first integrated gate commutated thyristor. The anode of the first integrated gate commutated thyristor is used to connect to the positive terminal of the DC bus, the cathode of the first integrated gate commutated thyristor is connected to the poloidal field coil, and the gate of the first integrated gate commutated thyristor is connected to the first control terminal of the control module. The second switching transistor is a second integrated gate commutated thyristor. The anode of the second integrated gate commutated thyristor is connected to the second terminal of the first switching circuit and the poloidal field coil, respectively. The cathode of the second integrated gate commutated thyristor is used to connect to the negative terminal of the DC bus. The gate of the second integrated gate commutated thyristor is connected to the second control terminal of the control module.

6. The dual load inverter module of claim 2, wherein, The first switching transistor is a first field-effect transistor, and the gate of the first field-effect transistor is connected to the first control terminal of the control module; The second switch is a second field-effect transistor, and the gate of the second field-effect transistor is connected to the second control terminal of the control module.

7. The dual load inverter module of claim 1, wherein, Also includes: A protection module is provided, which is connected to the first half-bridge and the second half-bridge of each of the bridge arms respectively. The protection module is used to disconnect the first half-bridge and the second half-bridge of each of the bridge arms in the event of a fault.

8. An inverter system, characterized in that, It includes multiple dual-load inverter modules as described in any one of claims 1-7, wherein each dual-load inverter module is connected in parallel and / or cascaded.

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