An improved gradient amplifier module

Abstract

The present invention discloses an improved gradient amplifier module, which includes a gradient control unit, a power conversion unit, a PWM driving unit, an output filtering unit, an energy storage unit, and a heat treatment unit; the power conversion unit is above the heat treatment unit, and the power electronic devices in the power conversion unit are fixed on the water-cooled plate of the heat treatment unit; the PWM driving unit is above the power conversion unit and is signal-connected to the power conversion unit; the gradient control unit is above the PWM driving unit and the power conversion unit and is signal-connected to the PWM driving unit and the power conversion unit; the filter inductor in the output filtering unit is connected to the power conversion unit and is placed on a metal component connected to the water-cooled plate in the heat treatment unit. Through reasonable layout, ingenious space utilization, and appropriate isolation and shielding, the present invention realizes the advantages of compact structure, high power density, good integration, optimal EMC, and low cost, occupying a small space and having a low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear magnetic resonance imaging, and particularly relates to an improved gradient amplifier module. Background Art

[0002] The gradient system is an important part of a nuclear magnetic resonance imaging system. Its function is to generate magnetic field gradients in the X-axis, Y-axis, and Z-axis directions of the magnetic resonance imaging spatial region, and use the magnetic field gradients for spatial encoding for imaging.

[0003] The above-mentioned "magnetic field gradient" is generated by the gradient system, which consists of a gradient amplifier and a gradient coil. The gradient amplifier drives the gradient coil to provide an accurate current with a fidelity that meets the requirements of nuclear magnetic resonance imaging, so that the gradient coil generates a linearly varying magnetic field, i.e., a gradient magnetic field, in the imaging space. For the gradient amplifier, the stability of its output current, high current change rate, low steady-state current fluctuation, and waveform tracking ability determine the quality of the gradient magnetic field performance, and the performance of the gradient magnetic field directly affects the imaging quality and the diagnostic results for the human body.

[0004] The gradient amplifier is an independent cabinet, including a set of gradient power supplies, three sets of gradient amplifier modules (in the X, Y, and Z directions), sensor components, water-cooling components and other accessories. The gradient power supply is an AC-DC voltage source, which converts the input AC mains power into a stable voltage source and supplies it to the gradient amplifier modules in three directions. The gradient amplifier module is the core key module of the gradient amplifier, including a gradient control unit, a power conversion unit, a PWM drive unit, an output filter unit, an energy storage unit, and a heat treatment unit. The gradient amplifier module receives the gradient control signal from the control unit of the nuclear magnetic resonance imaging system. The sensor detects the feedback signal of the output current. After signal processing and calculation by the gradient control unit, a corresponding PWM signal is generated and enters the PWM drive unit to generate the drive signal of the power electronic device, driving the orderly switching of the power electronic device in the power conversion unit. The power conversion unit simultaneously receives the high-voltage DC power supply from the energy storage unit, and then forms a high-voltage PWM pulse. The output filter unit filters the high-voltage pulse to form the expected accurate current and outputs it to the gradient coil. The energy storage unit is used to store the DC voltage from the gradient power supply and supply it to the power conversion unit. The heat treatment unit is generally a water-cooled plate assembly, which transfers the heat generated by the power conversion unit and / or the filter unit to the external heat exchange unit. The gradient amplifier module realizes the precise control of weak signals and the precise output of high-voltage power supplies in a compact space without mutual influence. For the gradient amplifiers of other manufacturers, in order to prevent weak signals from being affected by high-voltage switching signals, the gradient control unit is spatially separated from the power conversion unit and the output filter unit. Such a design has a large space occupation, low power density, complex connections between each unit, and low integration degree of the single-direction gradient amplifier module. Summary of the Invention

[0005] In order to solve the defects and deficiencies existing in the above-mentioned prior art, the present invention provides an improved gradient amplifier module which realizes the advantages of compact structure, high power density, good integration, optimal EMC and low cost through reasonable layout, ingenious space utilization and appropriate isolation and shielding. It solves the problem that it is difficult to have both high power density and excellent system performance, and at the same time occupies a small space and has low cost.

[0006] The technical solution of the present invention is an improved gradient amplifier module, including: a gradient control unit, a power conversion unit, a PWM drive unit, an output filter unit, an energy storage unit and a heat treatment unit; the power conversion unit is above the heat treatment unit, and the power electronic devices in the power conversion unit are fixed on the water-cooled plate of the heat treatment unit; the PWM drive unit is above the power conversion unit and is signal-connected to the power conversion unit; the gradient control unit is above the PWM drive unit and the power conversion unit and is signal-connected to the PWM drive unit and the power conversion unit; the filter inductor in the output filter unit is connected to the power conversion unit and is placed on the metal component connected to the water-cooled plate in the heat treatment unit.

[0007] Preferably, the PWM drive unit can be physically in one component with the gradient control unit or physically in one component with the power conversion unit.

[0008] Preferably, the PWM drive unit is composed of two drive boards, which are respectively inserted on the drive pins of the power electronic devices of the power conversion unit, and the other end is electrically connected to the gradient control unit through a connector.

[0009] Preferably, the gradient control unit is fixed on a metal plate and is shielded and isolated from the power conversion unit below.

[0010] Preferably, the power conversion unit is electrically connected to the output filter unit and the energy storage unit through a metal adapter; an electrical shielding isolation is made between the power conversion unit and the output filter unit through a metal plate.

[0011] Preferably, the filter inductor box body in the output filter unit is fixed on the same metal plate as the water-cooled plate or the heat sink in the heat treatment unit, so as to conduct the heat generated by the filter inductor to the water-cooled plate or the heat sink.

[0012] Preferably, the main heat conversion component in the heat treatment unit can be a water-cooled plate or an air-cooled heat sink.

[0013] Preferably, the output filter board assembly in the output filter unit is placed vertically at the rear of the gradient amplifier module box body and is isolated from the filter inductor in the output filter unit by a vertical metal plate.

[0014] Preferably, the filter inductor in the output filter unit is electrically connected to the metal connector of the output filter board in the output filter unit, and then electrically connected to the output connection terminal block.

[0015] Through reasonable layout, ingenious space utilization, and appropriate isolation and shielding, the gradient amplifier module of the present invention achieves the advantages of compact structure, high power density, good integration, optimal EMC, and low cost, solves the problem that it is difficult to have both high power density and excellent system performance, and at the same time occupies a small space and has a low cost. Brief Description of the Drawings

[0016] Figure 1 is the three-dimensional decomposition of the gradient amplifier module according to the embodiment of the present invention Figure 1 ;

[0017] Figure 2 is the three-dimensional decomposition of the gradient amplifier module according to the embodiment of the present invention Figure 2 ;

[0018] Figure 3 is the assembly of the gradient amplifier module according to the embodiment of the present invention Figure 1 , the front and rear panels, the upper cover plate and the side plates are not shown;

[0019] Figure 4 is the three-dimensional decomposition of the gradient amplifier module without the box housing according to the embodiment of the present invention Figure 3 ;

[0020] Figure 5 is the assembly drawing of the power conversion unit and the heat treatment unit according to the embodiment of the present invention;

[0021] Figure 6 is the three-dimensional decomposition drawing of the electrical connection between the power conversion unit and the output filter unit according to the embodiment of the present invention;

[0022] Figure 7 is the three-dimensional decomposition drawing of the high-power connector part according to the embodiment of the present invention. Detailed Description of the Embodiments

[0023] The technical solutions proposed by the present invention will be described in more detail below in conjunction with specific embodiments. Obviously, the described embodiments are only some of the embodiments described by the present invention and do not represent all the technical methods required by the present invention. All technical deformations based on the present invention fall within the scope of the technical protection of the present invention.

[0024] Embodiment

[0025] A gradient amplifier module, referring to Figures 1-4 , includes:

[0026] The gradient control unit 10 includes a gradient control board 12 placed on an isolation support metal plate 11. The gradient control board 12 processes and calculates the input control signal, the sensor detection signal, and the detection signal from the power conversion board 24 to generate corresponding PWM signals, which are output to the PWM drive unit 30. The isolation support metal plate 11 serves the functions of EMC isolation and support for the gradient control board 12.

[0027] The power conversion unit 20: The power conversion board 24 receives the switching signal from the PWM drive unit 30, converts the high-voltage signal from the energy storage unit 50 into high-voltage pulses, and is electrically connected to the filter inductor 41 through a power connection component 22 fixed on the isolation board 23. The power conversion board 24 transmits the power supply, output current detection signal, and status signal to the gradient control board 12. The power electronic device 21 in the power conversion unit 20 is fixed on a water-cooled plate 61 in the heat treatment unit 60, and the heat generated by the power electronic device 21 is transferred out through the liquid flowing through the water-cooled plate 61.

[0028] The PWM drive unit 30 is connected to and receives the PWM signal from the gradient control board 12, converts it into a drive signal for the power electronic device 21, and is connected to the drive pin of the power electronic device 21. At the same time, it detects the status of the power electronic device 21 and transmits it back to the gradient control board 12.

[0029] Optionally, the PWM drive unit 30 can be integrated within the gradient control board 12 or within the power conversion board 24.

[0030] The output filter unit 40 includes a filter inductor 41, an output filter board 42, a filter support board 43, a snubber resistor 44, and a filter inductor housing 45. The input end of the filter inductor 41 is electrically connected to the power connection component 22, and the output end is connected to the output filter board 42. Together with the output filter board 42, they filter the high-voltage pulse signal to generate an expected precise current in the gradient coil. The filter support board 43 can both support the output filter board 42 and isolate the electromagnetic energy generated by the filter inductor to avoid affecting the output stability. The snubber resistor 44, together with the output filter board 42, absorbs the energy of the switching pulse spikes. The filter inductor housing 45 houses and fixes the filter inductor 41, and transfers the heat generated by the filter inductor 41 to the support and heat conduction board 62 through the thermal conductive silicone inside it.

[0031] The energy storage unit 50 consists of an energy storage capacitor 51, a capacitor fixing plate 52, and a connection bar 53. The energy storage capacitor 51 is fixed on the capacitor fixing plate 52, and the capacitor fixing plate 52 is further fixed to the chassis. The connection bar 53 serves the function of series-parallel connection of the capacitors. The external high-voltage is electrically connected to the energy storage capacitor 51, and the energy storage capacitor 51 is then connected to the power input end of the power conversion board 24 through the connection power connection component 22.

[0032] Optionally, the energy storage unit 50 can be distributed in the power conversion unit 20, integrated in the gradient power supply, or separately provided outside.

[0033] The heat treatment unit 60 includes a water-cooled plate 61, a heat conduction plate 62, a water-cooled joint 63, and a water-cooled plate fixing member 64. The water-cooled plate 61 is fixed to the heat conduction plate 62 through the water-cooled plate fixing member 64, and at the same time, the filter inductor box body 45 is also fixed to the heat conduction plate 62. The liquid flowing in and out of the water-cooled plate 61 through the water-cooled joint 63 transfers heat, enabling each device to operate within a safe temperature range and ensuring the working safety of the power unit.

[0034] Optionally, the heat treatment unit 60 can also adopt an air-cooling form, replacing the water-cooled plate with a heat sink to transfer heat.

[0035] Optionally, in the heat treatment unit 60, the water-cooled joint 63 is placed Figure 3 in a vertical manner with respect to the water-cooled plate 61. This design and placement method are beneficial for saving space and preventing water from spraying into the gradient amplifier module in case of leakage. It is a relatively preferred form, and other forms and positions can also be used as the interface for the liquid to flow in and out of the water-cooled plate, such as different orientations or directly presenting in the form of a water pipe nozzle.

[0036] The optional component power connector 70, as an optional transfer connector for high-voltage power input and gradient current output, serves as a transfer for the electrical connection inside and outside the gradient amplifier module box, making the gradient amplifier module box more convenient for connection and maintenance. The insulating fixing block 72, inner fixing member 71, outer fixing member 76, connecting copper bar 73, and pressing plate 77 together form a gradient output connector, and the insulating fixing block 74, inner fixing member 71, outer fixing member 76, connecting copper bar 75, and pressing plate 78 together form a gradient high-voltage input connector. Through this design, on the premise of ensuring high-voltage insulation and passing large currents, a compact and delicate structure is achieved without occupying extra space.

[0037] The above power connector 70 is a relatively preferred design, and it can also be implemented in other ways, such as placing a finished high-power connector, or even not placing a connector and directly using the output filter board connector and energy storage capacitor as the connection end.

[0038] In this embodiment, referring to Figure 3 and Figure 4 , the gradient amplifier module is divided by the isolation plate 23. The front half part adopts a stacked structure of upper and lower layers. From bottom to top, there are a heat conduction plate 62, a water-cooled plate 61, power electronic devices 21, a power conversion board 24, a PWM drive unit 30, an isolation support metal plate 11, and a gradient control board 12. The functions are layered, the structure is compact, and the EMC requirements are met.

[0039] The filtering inductor 41 is placed inside the filtering box 45, and the layout is as Figure 3 shown to ensure that the two filtering inductors do not affect each other. At the same time, the isolation board 23 is used to isolate from the power conversion unit to ensure that the filtering inductor does not affect the signal of the power conversion unit.

[0040] Optionally, the specific implementation of the power connection component 22 is as Figure 6 shown, and it is composed of an isolation metal plate 23a, an insulating fixture 22d, a connecting metal part 22c, and an insulating pressing plate 22b.

[0041] As the power connection component 22, the above composition is only one relatively preferred implementation, and it can also be connected in other ways, such as soft copper wire or hard copper wire, etc.

[0042] The output filtering board 42 is placed vertically near the gradient output terminal, which saves space and reduces the connection distance and loop area of the output line, and is a relatively preferred solution. It can also be placed in other ways and positions.

[0043] In summary, the gradient amplifier module of the embodiment of the present invention realizes a design scheme with a compact structure, high power density, good integration, optimal EMC, and low cost through reasonable layout, ingenious space utilization, and appropriate isolation and shielding, solves the problem that it is difficult to have both high power density and excellent system performance, and at the same time, the preferred solution occupies a small space and has a low cost.

[0044] The embodiment of the present invention also provides a gradient amplifier, which includes the gradient amplifier module described in any one of the above.

[0045] The embodiment of the present invention also provides a gradient system, which includes the gradient amplifier described in any one of the above.

[0046] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. An improved gradient amplifier module, characterized in that: include: A gradient control unit, a power conversion unit, a PWM drive unit, an output filter unit, an energy storage unit and a heat treatment unit; the power conversion unit is located above the heat treatment unit, and the power electronic device in the power conversion unit is fixed on the heat treatment unit; the PWM drive unit is located above the power conversion unit and is connected to the power conversion unit signal; the gradient control unit is located above the PWM drive unit and the power conversion unit and is connected to the PWM drive unit and the power conversion unit signal; the filter inductor in the output filter unit is connected to the power conversion unit and is placed on a metal component connected to the water cooling plate in the heat treatment unit; The gradient control unit is fixed on a metal plate and is shielded and isolated from the power conversion unit below; The power conversion unit and the output filter unit are electrically shielded and isolated by a metal plate; The output filter unit includes a filter inductor, an output filter board, a filter support board, an absorption resistor and a filter inductor box body. The filter inductor input end is electrically connected to the power connection component, and the output end is connected to the output filter board. Together with the output filter board, the filter inductor filters the high-voltage pulse signal to generate the expected accurate current in the gradient coil. The filter support board can not only support the output filter board, but also isolate the electromagnetic energy generated by the filter inductor to avoid affecting the output stability. The absorption resistor and the output filter board absorb the switch pulse spike energy. The filter inductor box body carries and fixes the filter inductor, and transfers the heat generated by the filter inductor to the heat conduction plate through the thermal conductive silica gel therein. The output filter board assembly in the output filter unit is placed vertically at the rear of the gradient amplifier module box, and is isolated from the filter inductor in the output filter unit by a vertical metal plate; The PWM drive unit is composed of two drive boards, which are respectively inserted into the drive pins of the power electronic device of the power conversion unit, and the other end is electrically connected to the gradient control unit through a connector.

2. The improved gradient amplifier module according to claim 1, characterized in that: The PWM driving unit may be physically contained in one component together with the gradient control unit, or may be physically contained in one component together with the power conversion unit.

3. The improved gradient amplifier module according to claim 1, characterized in that: The power conversion unit is electrically connected to the output filter unit and the energy storage unit through a metal adapter.

4. The improved gradient amplifier module according to claim 1, characterized in that: The filter inductor box in the output filter unit is fixed on the same metal plate as the water cooling plate or heat sink in the heat treatment unit, so as to conduct the heat generated by the filter inductor to the water cooling plate or heat sink.

5. The improved gradient amplifier module according to claim 1, characterized in that: The main heat conversion component in the heat treatment unit can be a water-cooled plate or an air-cooled heat sink.

6. The improved gradient amplifier module according to claim 1, characterized in that: The filter inductor in the output filter unit is electrically connected to the metal connector of the output filter board in the output filter unit, and then electrically connected to the output connection terminal row.

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