Uniform field power supply device and magnetic resonance imaging equipment

Abstract

The invention discloses a shimming power supply device and a magnetic resonance imaging device. The shimming power supply device is used for the magnetic resonance imaging device. The magnetic resonance imaging device includes a gradient power amplifier device. The gradient power amplifier device includes an ACDC module. The shimming power supply device includes an inverter module. The first input end of the inverter module is connected to the first DC output end of the ACDC module. The second input end of the inverter module is connected to the second DC output end of the ACDC module. The first output end of the inverter module is connected to the first end of the shimming coil. The second output end of the inverter module is connected to the second end of the shimming coil. The shimming power supply device is used to receive a DC signal output by the ACDC module, invert the DC signal, and output a driving signal to drive the shimming coil to generate a uniform electric field. The shimming power supply device saves the ACDC rectifier module of the shimming power supply device by reusing the ACDC module in the gradient power amplifier device, thereby greatly saving the cost and volume of the shimming power supply device.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic resonance imaging equipment, and in particular to a uniform field power supply device and a magnetic resonance imaging equipment. Background Art

[0002] Since there are up to five output channels for the shim power supply, five groups of shim coils need to be compensated simultaneously, and additional fans are required to assist in heat dissipation, so the volume is relatively large.

[0003] Since the uniform field power supply is large in size, it needs to be installed independently inside the system cabinet, which not only takes up space but also has a high cost. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art to at least some extent. To this end, one object of the present invention is to provide a shim power supply device, which saves the ACDC rectifier module of the shim power supply device by reusing the ACDC module in the gradient power amplifier device, thereby greatly saving the cost and volume of the shim power supply device.

[0005] A second object of the present invention is to provide a magnetic resonance imaging device.

[0006] To achieve the above-mentioned purpose, a first aspect of the present invention provides a shim power supply device for a magnetic resonance imaging device, wherein the magnetic resonance imaging device includes a gradient power amplifier device, wherein the gradient power amplifier device includes an ACDC module, and the shim power supply device includes: an inverter module, wherein a first input end of the inverter module is connected to a first DC output end of the ACDC module, a second input end of the inverter module is connected to a second DC output end of the ACDC module, a first output end of the inverter module is connected to a first end of a shim coil, and a second output end of the inverter module is connected to a second end of the shim coil, and the shim power supply device is used to receive a DC signal output by the ACDC module, invert the DC signal, and output a drive signal to drive the shim coil to generate a uniform electric field.

[0007] According to the shimming power supply device of the embodiment of the present invention, the ACDC module in the gradient power amplifier device is reused to save the ACDC rectifier module of the shimming power supply device, and the DC signal output by the ACDC module is inverted by the inverter module to provide the driving current required by the shimming coil. The embodiment of the present invention greatly saves the cost and volume of the shimming power supply device.

[0008] In addition, the shim power supply device according to the above embodiment of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present invention, the shim power supply device further includes: a filter module, the filter module is connected between the inverter module and the shim coil, a first input end of the filter module is connected to a first output end of the inverter module, a second input end of the filter module is connected to a second output end of the inverter module, a first output end of the filter module is connected to a first end of the shim coil, and a second output end of the filter module is connected to a second end of the shim coil, for filtering the drive signal.

[0010] According to one embodiment of the present invention, the inverter module includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, the drain of the first switch tube is connected to the first input end of the inverter module, the source of the first switch tube is connected to the first output end of the inverter module, the source of the first switch tube is connected to the drain of the second switch tube, the source of the second switch tube is connected to the second input end of the inverter module, the drain of the third switch tube is connected to the first input end of the inverter module, the source of the third switch tube is connected to the second output end of the inverter module, the source of the third switch tube is connected to the drain of the fourth switch tube, and the source of the fourth switch tube is connected to the second input end of the inverter module.

[0011] According to an embodiment of the present invention, the four switch tubes in the inverter module are all N-type SIC MOSFETs, and the switching frequency of the SIC MOSFET is greater than 500 KHz.

[0012] According to one embodiment of the present invention, the filtering module includes: a first inductor, a first capacitor, a first resistor, a second resistor, a second capacitor and a second inductor, the first end of the first inductor is connected to the first input end of the filtering module, the second end of the first inductor is connected to the first end of the first capacitor to form a first node, the first node is connected to the first output end of the filtering module, the second end of the first capacitor is connected to the first end of the first resistor, the second end of the first resistor is grounded, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the second inductor to form a second node, the second node is connected to the second output end of the filtering module, and the second end of the second inductor is connected to the second input end of the filtering module.

[0013] According to one embodiment of the present invention, the uniform field power supply device also includes: a digital signal processing module, the output end of the digital signal processing module is connected to the gates of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube of the inverter module, and is used to control the on and off of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube to adjust the duty cycle of the inverter module.

[0014] According to one embodiment of the present invention, the uniform field power supply device further includes: a DCDC module, wherein a first DC input end of the DCDC module is connected to a first DC end of the ACDC module, a second DC input end of the DCDC module is connected to a second DC output end of the ACDC module, a first DC output end of the DCDC module is connected to a first input end of the digital signal processing module, and a second DC output end of the DCDC module is connected to a second input end of the digital signal processing module, for performing voltage reduction processing on a DC signal output by the ACDC module and providing voltage to the digital signal processing module.

[0015] According to one embodiment of the present invention, the ACDC module includes: a first rectifier diode, a second rectifier diode and an energy storage capacitor, the AC input end of the first rectifier diode is connected to the first AC input end of the ACDC module, the AC input end of the second rectifier diode is connected to the second AC input end of the ACDC module, the first DC output end of the first rectifier diode is connected to the first end of the energy storage capacitor, the second DC output end of the first rectifier diode is connected to the second end of the energy storage capacitor, the first DC output end of the second rectifier diode is connected to the first end of the energy storage capacitor, the second DC output end of the second rectifier diode is connected to the second end of the energy storage capacitor, the first end of the energy storage capacitor is connected to the first DC output end of the ACDC module, and the second end of the energy storage capacitor is connected to the second DC output end of the ACDC module, wherein the first AC input end and the second AC input end of the ACDC module are respectively connected to the secondary side of the transformer.

[0016] According to an embodiment of the present invention, the ACDC module is provided with a mechanical interface, and the shim power supply device is connected to the ACDC module via the mechanical interface.

[0017] To achieve the above-mentioned object, a second embodiment of the present invention proposes a magnetic resonance imaging device, which includes a gradient power amplifier device and a uniform field power supply device as proposed in the first embodiment of the present invention, wherein the gradient power amplifier device includes an ACDC module.

[0018] In addition, the magnetic resonance imaging device proposed in the above embodiment of the present invention may also have the following additional technical features:

[0019] According to an embodiment of the present invention, the device further comprises: a communication device, which is connected to the gradient power amplifier device and is used to provide a communication interface for the gradient power amplifier device and the shim power supply device.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a system cabinet when a conventional shim power supply device is installed in the system cabinet is shown;

[0022] Figure 2 Shows Figure 1 A three-dimensional diagram of a conventional shim power supply device;

[0023] Figure 3 is a schematic diagram of a gradient power amplifier device according to an embodiment of the present invention;

[0024] Figure 4 is a schematic diagram of a gradient current waveform according to an embodiment of the present invention;

[0025] Figure 5 It is a schematic diagram of the connection between a shim power supply device and an ACDC module in a gradient power amplifier device according to an embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of a group of channel shim power supply devices according to an embodiment of the present invention;

[0027] Figure 7 is a schematic diagram of a single-channel shim power supply device according to another embodiment of the present invention;

[0028] Figure 8 is a schematic diagram of an inverter module according to an embodiment of the present invention;

[0029] Fig. 9 is a schematic diagram of a filter module according to an embodiment of the present invention;

[0030] Fig.10 is a schematic diagram of an inductor installed on a PCB board in a filter module according to an embodiment of the present invention;

[0031] Fig.11 is a schematic diagram of a single-channel shim power supply device according to another embodiment of the present invention;

[0032] Fig.12 is a schematic diagram of the shimming control principle of an embodiment of the present invention;

[0033] Fig.13is a schematic diagram of a shim current waveform according to an embodiment of the present invention;

[0034] FIG. 14( a ) is a three-dimensional diagram of a DCDC module according to an embodiment of the present invention;

[0035] FIG14( b ) is a front view and a top view of the DCDC module in FIG14( a );

[0036] Fig.15 is a three-dimensional diagram of a single-channel shim power supply device according to an embodiment of the present invention;

[0037] Fig.16 It is a schematic diagram of an interface of a single-channel shim power supply device according to an embodiment of the present invention;

[0038] Fig.17 is a three-dimensional diagram of a gradient power amplifier device of an integrated shim power supply device according to an embodiment of the present invention;

[0039] Fig.18 It is a schematic diagram of the connection between a shim power supply device and a gradient power amplifier device according to another embodiment of the present invention;

[0040] Fig.19 is a schematic diagram of a magnetic resonance imaging apparatus according to an embodiment of the present invention;

[0041] FIG. 20( a ) is a schematic diagram showing the connection between a gradient power amplifier device and a communication device of a conventional shim power supply device;

[0042] FIG. 20( b ) is a schematic diagram showing the connection between the gradient power amplifier device and the communication device of the uniform field power supply device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0044] It should be noted that Figure 1 FIG. 1 shows a schematic diagram of a system cabinet when a conventional shim power supply device is installed in the system cabinet, wherein: Figure 1 The rectangular white box in the figure is the area occupied by the traditional uniform field power supply device. Figure 2 Shows Figure 1 Three-dimensional diagram of a conventional shim power supply device. Figure 2 The conventional uniform field power supply device is 400 mm long, 475 mm wide and 482 mm high.

[0045] In order to solve the problem that shimming power supplies occupy space and have high costs, the present invention provides a shimming power supply device and a magnetic resonance imaging device. The shimming power supply device and the magnetic resonance imaging device of the present invention are described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0046] The uniform field power supply device of the embodiment of the present invention is used in a magnetic resonance imaging device. The magnetic resonance imaging device includes a gradient power amplifier device. The gradient power amplifier device includes an ACDC module.

[0047] It should be noted that the gradient amplifier (GA) device used in MRI (Magnetic Resonance Imaging) equipment uses different circuit topologies to achieve precise control of the current of the gradient coil (GC) to achieve the purpose of imaging.

[0048] The gradient power amplifier device of each channel in the embodiment of the present invention adopts a CHB (Cohen-Hewitt-Bank) topology structure.

[0049] As a specific embodiment, Figure 3 As shown, the gradient power amplifier device of the CHB topology structure includes: an ACDC (Alternating Current / Direct Current, alternating current and direct current) module and a post-stage DCAC (Direct Current / Alternating Current, direct current and alternating current) module.

[0050] The ACDC module uses three-phase rectifier diodes to convert the AC input of the secondary side of transformer D (Y1 and D1, Y2 and D2, Y3 and D3) into DC output on the energy storage capacitor, and supplies power to the subsequent DCAC module. The DCAC module achieves precise current control of the gradient coil through high-frequency switching.

[0051] In this embodiment, the ACDC1 module converts the AC input of the transformer D secondary side Y1 and D1 into a DC output on the energy storage capacitor in the ACDC1 module, where the output voltage is VBUS1. The ACDC2 module converts the AC input of the transformer D secondary side Y2 and D2 into a DC output on the energy storage capacitor in the ACDC2 module, where the output voltage is VBUS2. The ACDC3 module converts the AC input of the transformer D secondary side Y3 and D3 into a DC output on the energy storage capacitor in the ACDC3 module, where the output voltage is VBUS3. Wherein, VBUS1=VBUS2=VBUS3. Figure 3 The Y and D marked on the secondary side of transformer D refer to different connection methods of the windings. Y connection represents star connection, and D connection represents triangle connection.

[0052] The typical gradient current Igc waveform is as follows: Figure 4 As shown, the relationship between the gradient coil voltage Vgc and the energy storage capacitor voltage (the voltage output by the ACDC1 module) VBUS is as follows: Vgc=3×(2D-1)×VBUS, where Vgc represents the gradient coil voltage, D represents the duty cycle, and VBUS represents the energy storage capacitor voltage.

[0053] The gradient coil in the embodiment of the present invention can be equivalent to an air inductor with an inductance L and a resistance R, and its voltage Vgc is: Wherein, Vgc represents the gradient coil voltage, Lgc represents the inductance, Igc represents the current, and Rgc represents the resistance.

[0054] The gradient coil in the magnetic resonance imaging device is composed of three main coils, X, Y, and Z, and is mainly used for human body position encoding. The corresponding magnetic resonance imaging device is equipped with a three-channel gradient power amplifier device, which is used to drive the three main coils, X, Y, and Z, respectively.

[0055] In some high-end applications, such as 3T (Tesla) MRI equipment, the gradient coil will have up to 5 sets of auxiliary coils, called shim coils, which are used to compensate for high-order distortion of the magnetic field and improve imaging quality. Each set of shim coils requires a set of shim power devices to drive the shim coils of the channel.

[0056] The shim coil in the embodiment of the present invention may be equivalent to an LR combination.

[0057] Figure 5 The present invention is a schematic diagram of the connection between a shim power supply device and an ACDC module in a gradient power amplifier device according to an embodiment of the present invention. The shim power supply device according to the embodiment of the present invention reuses the ACDC module in the gradient power amplifier device. The DC signal output by the ACDC module in the gradient power amplifier device is used as an input signal of the shim power supply device, and the shim coil is driven based on the input signal.

[0058] Figure 6 Schematic diagram of a group of channel shim power supply devices according to an embodiment of the present invention. Figure 6 As shown, the shim power supply device may include:

[0059] An inverter module, wherein a first input end of the inverter module is connected to a first DC output end of the ACDC module, a second input end of the inverter module is connected to a second DC output end of the ACDC module, a first output end of the inverter module is connected to a first end of the shim coil, and a second output end of the inverter module is connected to a second end of the shim coil, is used to receive a DC signal output by the ACDC module, invert the DC signal, and output a driving signal to drive the shim coil to generate a uniform electric field.

[0060] The shim power supply device in the embodiment of the present invention reuses the ACDC module in the gradient power amplifier device and directly draws power from the ACDC module. The ACDC module required by the shim power supply device can be directly omitted, thereby greatly saving cost and volume.

[0061] The voltage (VBUS) of the DC signal output by the ACDC module in the gradient power amplifier device in the embodiment of the present invention is close to 400V (volts), and the current is greater than 50A (amperes). In the embodiment of the present invention, the driving voltage Vshim of the shimming coil is less than 100V, and the driving current Ishim is generally less than 10A. Therefore, the DC signal output by the ACDC module in the gradient power amplifier device is used as the input signal of the shimming power supply device, which fully meets the requirement that the output voltage of the shimming power supply device is less than 100V.

[0062] The embodiment of the present invention uses an inverter module to invert the DC signal output by the ACDC module. Specifically, the input end of the inverter module is connected to the DC output end of the ACDC module, the inverter module receives the DC signal output by the ACDC module, and inverts the received DC signal to output the driving current required by the shim coil. The inverter module outputs the driving signal to drive the shim coil to generate a uniform electric field.

[0063] The shim power supply device of the embodiment of the present invention saves the ACDC rectifier module of the shim power supply device by reusing the ACDC module in the gradient power amplifier device, and uses the inverter module to invert the DC signal output by the ACDC module to provide the driving current required by the shim coil, thereby greatly saving the cost and volume of the shim power supply device.

[0064] In one embodiment of the present invention, Figure 6 As shown, the ACDC module includes: a first rectifier diode, a second rectifier diode and an energy storage capacitor, the AC input end of the first rectifier diode is connected to the first AC input end of the ACDC module, the AC input end of the second rectifier diode is connected to the second AC input end of the ACDC module, the first DC output end of the first rectifier diode is connected to the first end of the energy storage capacitor, the second DC output end of the first rectifier diode is connected to the second end of the energy storage capacitor, the first DC output end of the second rectifier diode is connected to the first end of the energy storage capacitor, the second DC output end of the second rectifier diode is connected to the second end of the energy storage capacitor, the first end of the energy storage capacitor is connected to the first DC output end of the ACDC module, and the second end of the energy storage capacitor is connected to the second DC output end of the ACDC module, wherein the first AC input end and the second AC input end of the ACDC module are respectively connected to the secondary side of the transformer.

[0065] In practice, the first rectifier diode is connected to the secondary triangle-connected winding of the transformer, and the second rectifier diode is connected to the secondary star-connected winding of the transformer. The ACDC module uses the first rectifier diode and the second rectifier diode to convert the AC power of the secondary side of the transformer into DC power and store it in the energy storage capacitor.

[0066] In an embodiment of the present invention, the rectifier diode may be a three-phase rectifier diode.

[0067] In one embodiment of the present invention, Figure 7 As shown, the shim power supply device also includes:

[0068] A filtering module is connected between the inverter module and the shim coil, a first input end of the filtering module is connected to a first output end of the inverter module, a second input end of the filtering module is connected to a second output end of the inverter module, a first output end of the filtering module is connected to a first end of the shim coil, and a second output end of the filtering module is connected to a second end of the shim coil, for filtering the driving signal.

[0069] In order to reduce the pulsation in the driving signal and smooth the inverted driving signal, the embodiment of the present invention provides a filtering module between the inversion module and the shim coil.

[0070] Specifically, the input end of the filter module is connected to the output end of the inverter module, and the output end of the filter module is connected to both ends of the shim coil. The filter module receives the drive signal output by the inverter module and filters the drive signal so that the drive signal received by the shim coil is smoother and closer to the drive signal required by the shim coil.

[0071] In one embodiment of the present invention, Figure 8 As shown, the inverter module includes a first switch tube NMOS1, a second switch tube NMOS2, a third switch tube NMOS3 and a fourth switch tube NMOS4, the drain of the first switch tube NMOS1 is connected to the first input end of the inverter module, the source of the first switch tube NMOS1 is connected to the first output end of the inverter module, the source of the first switch tube NMOS1 is connected to the drain of the second switch tube NMOS2, the source of the second switch tube NMOS2 is connected to the second input end of the inverter module, the drain of the third switch tube NMOS3 is connected to the first input end of the inverter module, the source of the third switch tube NMOS3 is connected to the second output end of the inverter module, the source of the third switch tube NMOS3 is connected to the drain of the fourth switch tube NMOS4, and the source of the fourth switch tube NMOS4 is connected to the second input end of the inverter module.

[0072] The inverter module in the embodiment of the present invention may include an H-bridge, and the H-bridge is used to invert the DC signal output by the ACDC module.

[0073] Specifically, by controlling the on-off duration of the first switch tube NMOS1, the second switch tube NMOS2, the third switch tube NMOS3 and the fourth switch tube NMOS4 in the H bridge, the duty cycle of the inverter module is adjusted so that the inverter module can invert the voltage of the DC signal output by the ACDC module to the driving voltage required by the shim coil.

[0074] In one embodiment of the present invention, the four switch tubes in the H bridge are all N-type SIC MOSFETs, and the switching frequency of the SIC MOSFET is greater than 500 KHz.

[0075] It should be noted that the conventional shim power supply device uses SIMOSFET, which has low cost but high loss, and the switching frequency is less than 100KHZ, and an external heat sink is required, such as using a fan to force air cooling to assist in heat dissipation.

[0076] In the embodiment of the present invention, the four switch tubes in the inverter module are all SIC MOSFET. The cost of SIC MOSFET is basically the same as that of SIMOSFET, but the loss is greatly reduced. The switching frequency of SIC MOSFET is above 500KHZ, and the heat dissipation requirements can be met by natural cooling of PCB (Printed Circuit Board).

[0077] It should be noted that the embodiment of the present invention does not limit the model of the switch tube, and it can also be a switch tube with other high-frequency switching frequencies (above 500KHZ).

[0078] The high switching frequency switch tube of the embodiment of the present invention reduces the power consumption of the device, so that the inverter module can use natural cooling without the need for a fan to assist in heat dissipation, further reducing costs and saving space.

[0079] In one embodiment of the present invention, Fig. 9 As shown, the filtering module includes: a first inductor L1, a first capacitor C1, a first resistor R1, a second resistor R2, a second capacitor C2 and a second inductor L2, the first end of the first inductor L1 is connected to the first input end of the filtering module, the second end of the first inductor L1 is connected to the first end of the first capacitor C1, and form a first node, the first node is connected to the first output end of the filtering module, the second end of the first capacitor C1 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is grounded, the second end of the first resistor R1 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the first end of the second capacitor C2, the second end of the second capacitor C2 is connected to the first end of the second inductor L2, and form a second node, the second node is connected to the second output end of the filtering module, and the second end of the second inductor L2 is connected to the second input end of the filtering module.

[0080] Specifically, the driving signal is filtered by a filtering module composed of the first inductor L1, the first capacitor C1, the first resistor R1, the second resistor R2, the second capacitor C2 and the second inductor L2, so that the driving signal received by the shim coil is smoother and closer to the ideal driving signal.

[0081] As the switching frequency of the four switching tubes in the inverter module increases, the volume of the post-stage filter module can be reduced accordingly, especially the inductor (the first inductor L1 and the second inductor L2). After the inductance value becomes smaller, the filter inductor can be integrated into the PCB to further save space and cost. The winding of the inductor (the first inductor L1 and the second inductor L2) is completed through PCB routing, and the heat is dissipated through the PCB, such as Fig.10 shown.

[0082] Since the uniform field power supply has low power, the output voltage of each channel is less than 100V and the current is less than 10A. With the emergence of a new generation of power semiconductors SIC and GaN, high-frequency power supply has become a reality. By increasing the switching frequency of the switch tube in the H-bridge (>500KHZ), the power consumption of the switch tube has not increased significantly, and the temperature is controlled. At the same time, the size of the components in the filter module can be greatly reduced and can be integrated into the PCB. The overall thermal performance requirements can be met through natural cooling, thus realizing a miniaturized modular design.

[0083] In one embodiment of the present invention, Fig.11 As shown, the uniform field power supply device also includes: a digital signal processing module, the output end of the digital signal processing module is connected to the gates of the first switch tube NMOS1, the second switch tube NMOS2, the third switch tube NMOS3 and the fourth switch tube NMOS4 of the inverter module, and is used to control the on and off of the first switch tube NMOS1, the second switch tube NMOS2, the third switch tube NMOS3 and the fourth switch tube NMOS4 to adjust the duty cycle of the inverter module.

[0084] Specifically, a digital signal processing module (DSP) is used to control the on and off of the first switch tube NMOS1, the second switch tube NMOS2, the third switch tube NMOS3 and the fourth switch tube NMOS4, and adjust the duty cycle of the inverter module, so that the inverter module can adjust the DC signal output by the ACDC module to the driving signal required by the shim coil.

[0085] In one embodiment of the present invention, Fig.11As shown, the uniform field power supply device also includes: a DCDC module, a first DC input end of the DCDC module is connected to a first DC output end of the ACDC module, a second DC input end of the DCDC module is connected to a second DC output end of the ACDC module, a first DC output end of the DCDC module is connected to a first input end of the digital signal processing module, and a second DC output end of the DCDC module is connected to a second input end of the digital signal processing module, for performing voltage reduction processing on a DC signal output by the ACDC module and providing voltage to the digital signal processing module.

[0086] The DSP module in the embodiment of the present invention is connected to the ACDC module via the DCDC module, and the DCDC module is used to reduce the voltage of the DC signal output by the ACDC module to provide a driving voltage for the DSP module.

[0087] Specifically, the DC input terminal of the DCDC module is connected to the DC output terminal of the ACDC module, and the DC output terminal of the DCDC module is connected to the input terminal of the DSP module to provide the DSP module with the required driving voltage.

[0088] The embodiment of the present invention uses a controller to control the PWM (Pulse Width Modulation) control signal output by the DSP module to adjust the duty cycle of the inverter module. The controller obtains the target current of the shim coil and the actual current of the shim coil, and uses a PID control algorithm to control the PWM control signal output by the DSP module to control the on and off and on and off duration of the first switch tube NMOS1, the second switch tube NMOS2, the third switch tube NMOS3 and the fourth switch tube NMOS4, adjust the duty cycle of the inverter module, and maintain the actual current of the shim coil at the target current, so that the shim coil generates a uniform electric field. It should be noted that Fig.11 The interface on one side of the DSP module is the communication interface of the DSP module, which is connected to the controller through the communication interface to receive the control signal input by the controller.

[0089] Specifically, Fig.12As shown, the controller obtains the target current Ierf of the shim coil and the real-time current Ishim of the shim coil collected by the HALL element. The ADC (Analog-to-Digital Converter) module converts the difference between the target current Ierf and the real-time current Ishim into a digital signal, and uses the PID control algorithm to control the transfer function Gid(s) of the input current to the control voltage to control the PWM control signal output by the DSP module. The PWM control signal drives the gates of the first switch tube NMOS1, the second switch tube NMOS2, the third switch tube NMOS3 and the fourth switch tube NMOS4 through optical coupling isolation to adjust the duty cycle of the inverter module so that the real-time current of the shim coil is maintained at the target current. Among them, the waveform of the shim coil is as follows Fig.13 shown.

[0090] In the embodiment of the present invention, the uniform field power supply device draws power from VBUS, isolates it through the DCDC module, and supplies +3.3V to the DSP module. Since the power consumption of the DSP control circuit is less than 5W, the DCDC isolation power supply module is very small. Figure 14 (a) shows a three-dimensional diagram of a DCDC module of an embodiment. Among them, Figure 14 (b) shows the front view and top view of the DCDC module in Figure 14 (a) and its size. It can be seen from Figure 14 (b) that the length of the DCDC module is 19.50mm, the width is 12.50mm, and the height is 9.80mm.

[0091] In the uniform field power supply device in the embodiment of the present invention, the switching frequency of the switch tube in the inverter module is increased to more than 500KHZ, the loss of the SIC switch tube is very low, and natural cooling can be used, and heat dissipation through the PCB can be satisfied, so the inverter module can be made very small. Since the switching frequency of the switch tube in the inverter module is increased, the inductance value in the filter module becomes smaller and can be integrated into the PCB. The DSP module of the uniform field power supply device needs to be powered by a high-frequency DCDC module. Since the power consumption is <5W, the volume can be made very small.

[0092] Since the shimming power supply device in the embodiment of the present invention reuses the ACDC module in the gradient power amplifier device, the ACDC rectifier module of the traditional shimming power supply device is saved. The volume of the inverter module, the filter module, the DCDC module, and the DSP module can be made very small. Therefore, the shimming power supply in the embodiment of the present invention is integrated.

[0093] The size of the single-channel integrated shim power supply device in the embodiment of the present invention is as follows: Fig.15 As shown. Fig.15It can be seen that the length of the shim power supply device in the embodiment of the present invention is 100 mm, the width is 60 mm, and the height is less than 12 mm. Compared with the traditional shim power supply device (length 400 mm, width 475 mm, height 482 mm), the embodiment of the present invention greatly reduces the volume of the shim power supply device.

[0094] In one embodiment of the present invention, Fig.16 As shown, the ACDC module is provided with a mechanical interface, and the uniform field power supply device is connected to the ACDC module via the mechanical interface.

[0095] Due to the modular design of the ACDC in the gradient power amplifier, the integrated shim power supply also adopts a modular design and is integrated on a PCB. Therefore, it can be directly installed inside the ACDC module in the gradient power amplifier through the mechanical interface to achieve integration. For the location of the mechanical interface of the shim power supply set on the ACDC module, see Fig.16 The black box in the middle. Once miniaturized and integrated into the gradient amplifier ACDC, the system cabinet volume will be further reduced, saving costs and installation space.

[0096] Each channel of the integrated shimming power supply device is modularized, which is very easy to expand and maintain. The integrated shimming power supply device in the embodiment of the present invention can be directly integrated into the ACDC module in the gradient power amplifier device.

[0097] The ACDC module in the gradient power amplifier device in the embodiment of the present invention adopts fan-forced air cooling to dissipate heat, and the integrated shim power supply can meet the heat dissipation through natural cooling. Once integrated into the gradient power amplifier ACDC module, the fan-forced air cooling is reused to dissipate heat, and the thermal performance will be further improved. The three-dimensional diagram of the gradient power amplifier device with integrated shim power supply is shown in FIG. Fig.17 shown.

[0098] The shim power supply device in the embodiment of the present invention saves the ACDC rectifier module of the shim power supply device by reusing the ACDC module in the gradient power amplifier device, and uses the inverter module to invert the DC signal output by the ACDC module to provide the driving current required by the shim coil, thereby greatly saving the cost and volume of the shim power supply device.

[0099] The uniform field power supply device in the magnetic resonance imaging device has at most 5 groups of channels, and the gradient power amplifier device has at least 3 channels. For a 1.5T gradient power amplifier, a gradient power amplifier device of one channel has at least 3 ACDC modules, and a gradient power amplifier device of one channel is used for the gradient coil of one axis. Since the magnetic resonance imaging device has three axes, X, Y, and Z, there are a total of 9 ACDC modules. For a 3T system, a gradient power amplifier device of one channel has at least 5 ACDC modules, see Fig.18, a total of 15 ACDC modules, can expand up to 15 channels of shim power supply. Can better meet the future ultra-high performance gradient system needs.

[0100] The integrated shimming power supply device of the embodiment of the present invention directly draws power from VBUS by reusing the gradient power amplifier ACDC module, saving its own ACDC module, effectively reducing costs and reducing volume. At the same time, by reusing the internal thermal management system of the gradient power amplifier ACDC module, its own thermal performance can be further improved to better meet the future ultra-high gradient performance requirements of the system.

[0101] It should be noted that the ACDC module in the gradient power amplifier device can use any ACDC technology, including controllable and uncontrollable ACDC technologies. The embodiment of the present invention does not limit the ACDC module.

[0102] The invention provides a magnetic resonance imaging device.

[0103] Fig.19 FIG. 1 is a schematic diagram of a magnetic resonance imaging device according to an embodiment of the present invention. Fig.19 As shown, the magnetic resonance imaging device 1000 includes a gradient power amplifier device 200 and the above-mentioned shim power supply device 100, wherein the gradient power amplifier device 200 includes an ACDC module.

[0104] The shimming power supply device in the magnetic resonance imaging device 1000 of the embodiment of the present invention has at most 5 channels. For a 1.5T magnetic resonance imaging device, a gradient power amplifier device of one channel has at least 3 ACDC modules, and a gradient power amplifier device of one channel is used for a gradient coil of one axis. Since the magnetic resonance imaging device has three axes, X, Y, and Z, there are a total of 9 ACDC modules. For a 3T magnetic resonance imaging device, a gradient power amplifier device of one channel has at least 5 ACDC modules, a total of 15 ACDC modules, and a maximum of 15 channels of shimming power supplies can be expanded, which can better meet the needs of future ultra-high performance magnetic resonance imaging devices 1000.

[0105] In the embodiment of the present invention, there are at least three groups of gradient power amplifier devices 200 and at least five groups of shim power supply devices 100 in the magnetic resonance imaging device 1000. The embodiment of the present invention does not limit the number of gradient power amplifier devices 200 and shim power supply devices 100 in the magnetic resonance imaging device 1000.

[0106] In one embodiment of the present invention, the magnetic resonance imaging device 1000 further includes:

[0107] The communication device is connected to the gradient power amplifier device and is used to provide a communication interface for the gradient power amplifier device and the uniform field power supply device.

[0108] Specifically, the spectrometer, gradient power amplifier device, and shim power device of the magnetic resonance imaging device 1000 are connected via a communication device. Taking optical fiber communication as an example, in a traditional architecture, the spectrometer requires two pairs of high-speed optical communication modules to control the gradient power amplifier device and the shim power device respectively, as shown in FIG20(a).

[0109] The integrated shim power supply in the embodiment of the present invention can be integrated into the gradient power amplifier, thereby saving a set of high-speed optical communication modules, see FIG. 20( b ).

[0110] The integrated shim power supply of the embodiment of the present invention is integrated into the gradient power amplifier, which can simplify the communication interface of the magnetic resonance imaging device 1000 and reduce the communication cost.

[0111] In one embodiment of the present invention, the communication device comprises an electrical communication module and / or an optical fiber communication module.

[0112] Specifically, the spectrometer and the gradient power amplifier and the uniform field power supply can be connected via an electrical or optical fiber communication module.

[0113] The magnetic resonance imaging device in the embodiment of the present invention has the advantages of low cost and small size.

[0114] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0115] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0116] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0117] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0118] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0119] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A shim power supply device, characterized in that: Used in a magnetic resonance imaging device, the magnetic resonance imaging device comprises a gradient power amplifier device, the gradient power amplifier device comprises an ACDC module, and the shim power supply device comprises: An inverter module, wherein a first input end of the inverter module is connected to a first DC output end of the ACDC module, a second input end of the inverter module is connected to a second DC output end of the ACDC module, a first output end of the inverter module is connected to a first end of a shim coil, and a second output end of the inverter module is connected to a second end of the shim coil, and is used to receive a DC signal output by the ACDC module, invert the DC signal, and output a driving signal to drive the shim coil to generate a uniform electric field.

2. The shim power supply device according to claim 1, characterized in that: The shim power supply device also includes: A filtering module, wherein the filtering module is connected between the inverter module and the shim coil, a first input end of the filtering module is connected to a first output end of the inverter module, a second input end of the filtering module is connected to a second output end of the inverter module, a first output end of the filtering module is connected to a first end of the shim coil, and a second output end of the filtering module is connected to a second end of the shim coil, for filtering the driving signal.

3. The shim power supply device according to claim 1, characterized in that: The inverter module includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube. The drain of the first switch tube is connected to the first input end of the inverter module, the source of the first switch tube is connected to the first output end of the inverter module, the source of the first switch tube is connected to the drain of the second switch tube, the source of the second switch tube is connected to the second input end of the inverter module, the drain of the third switch tube is connected to the first input end of the inverter module, the source of the third switch tube is connected to the second output end of the inverter module, the source of the third switch tube is connected to the drain of the fourth switch tube, and the source of the fourth switch tube is connected to the second input end of the inverter module.

4. The shim power supply device according to claim 2, characterized in that: The four switch tubes in the inverter module all adopt N-type SIC MOSFET, and the switching frequency of the SIC MOSFET is greater than 500KHz.

5. The shim power supply device according to claim 2, characterized in that: The filtering module includes: a first inductor, a first capacitor, a first resistor, a second resistor, a second capacitor and a second inductor, wherein the first end of the first inductor is connected to the first input end of the filtering module, the second end of the first inductor is connected to the first end of the first capacitor to form a first node, the first node is connected to the first output end of the filtering module, the second end of the first capacitor is connected to the first end of the first resistor, the second end of the first resistor is grounded, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the second inductor to form a second node, the second node is connected to the second output end of the filtering module, and the second end of the second inductor is connected to the second input end of the filtering module.

6. The shim power supply device according to claim 1, characterized in that: The shim power supply device also includes: A digital signal processing module, wherein the output end of the digital signal processing module is connected to the gates of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube of the inverter module, and is used to control the on and off of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube to adjust the duty cycle of the inverter module.

7. The shim power supply device according to claim 6, characterized in that: The shim power supply device also includes: A DCDC module, wherein a first DC input end of the DCDC module is connected to a first DC end of the ACDC module, a second DC input end of the DCDC module is connected to a second DC output end of the ACDC module, a first DC output end of the DCDC module is connected to a first input end of the digital signal processing module, and a second DC output end of the DCDC module is connected to a second input end of the digital signal processing module, and is used to perform voltage reduction processing on a DC signal output by the ACDC module and provide voltage to the digital signal processing module.

8. The shim power supply device according to claim 1, characterized in that: The ACDC module includes: a first rectifier diode, a second rectifier diode and an energy storage capacitor, wherein the AC input end of the first rectifier diode is connected to the first AC input end of the ACDC module, the AC input end of the second rectifier diode is connected to the second AC input end of the ACDC module, the first DC output end of the first rectifier diode is connected to the first end of the energy storage capacitor, the second DC output end of the first rectifier diode is connected to the second end of the energy storage capacitor, the first DC output end of the second rectifier diode is connected to the first end of the energy storage capacitor, the second DC output end of the second rectifier diode is connected to the second end of the energy storage capacitor, the first end of the energy storage capacitor is connected to the first DC output end of the ACDC module, and the second end of the energy storage capacitor is connected to the second DC output end of the ACDC module, wherein the first AC input end and the second AC input end of the ACDC module are respectively connected to the secondary side of the transformer.

9. The shim power supply device according to claim 1, characterized in that: The ACDC module is provided with a mechanical interface, and the shim power supply device is connected to the ACDC module via the mechanical interface.

10. A magnetic resonance imaging device, characterized in that: The device comprises a gradient power amplifier device and a uniform field power supply device as claimed in any one of claims 1 to 9, wherein the gradient power amplifier device comprises an ACDC module.

11. The magnetic resonance imaging device according to claim 10, characterized in that The device also includes: A communication device is connected to the gradient power amplifier device and is used to provide a communication interface for the gradient power amplifier device and the shim power supply device.

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