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Series compensation circuit of gradient amplifier and nuclear magnetic resonance imaging equipment

A gradient amplifier and series compensation technology, which is applied to sensors, electrical components, output power conversion devices, etc., can solve the problems of difficult selection of switching tubes, large losses, and poor switching characteristics.

Active Publication Date: 2017-02-01
NEUSOFT MEDICAL SYST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, the next generation of nuclear magnetic resonance equipment requires a higher voltage of the gradient coil, so the driving current required by the gradient amplifier is also larger, which makes it difficult to select the switching tube in the H bridge, because the withstand voltage of the switching tube is limited. Yes, when IGBT is used as the switch tube at present, the highest withstand voltage of IGBT is 3.2kV
And as the withstand voltage of the switch tube increases, the loss will increase and the switching characteristics will also deteriorate. Therefore, the gradient amplifier with this architecture in the prior art will not be suitable for the requirements of the next generation of nuclear magnetic resonance equipment.

Method used

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  • Series compensation circuit of gradient amplifier and nuclear magnetic resonance imaging equipment
  • Series compensation circuit of gradient amplifier and nuclear magnetic resonance imaging equipment
  • Series compensation circuit of gradient amplifier and nuclear magnetic resonance imaging equipment

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Experimental program
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Embodiment 1

[0057] see figure 2 , which is a schematic diagram of Embodiment 1 of the series compensation circuit of the gradient amplifier provided by the present invention.

[0058] The series compensation circuit of the gradient amplifier provided in this embodiment includes: a first step-up transformer T1 and at least the following two inverters, namely: a first inverter 100 and a second inverter 200;

[0059] The first inverter 100 is configured to invert the first DC voltage VBUS1 into a first AC voltage V1;

[0060] The second inverter 200 is configured to invert the second DC voltage VBUS2 and input it to the input terminal of the first step-up transformer;

[0061] It can be understood that VBUS1 and VBUS2 can be equal or not.

[0062] The first step-up transformer T1 is used to step up the voltage at its input terminal to a second AC voltage V2;

[0063] The transformation ratio of the first step-up transformer T1 is 1:N, that is, the output voltage of T1 is N times the input ...

Embodiment 2

[0076] see Figure 5 , which is a schematic diagram of Embodiment 2 of the series compensation circuit of the gradient amplifier provided by the present invention.

[0077] The series compensation circuit of the gradient amplifier provided in this embodiment further includes: a current sensor 300, a difference circuit (not shown in the figure), a first controller 400 and a second controller 500;

[0078] The current sensor 300 is configured to obtain the current of the gradient coil 600, and feed back the current of the gradient coil 600 to the difference circuit;

[0079] The difference circuit is used to obtain the difference between the current of the gradient coil and the reference current, and send the difference to the first controller 400 and the second controller 500;

[0080] As shown in the figure, the difference circuit compares the current igc of the gradient coil 600 with the reference current iref to obtain the difference between the two. It should be noted tha...

Embodiment 3

[0088] see Figure 6a , which is a schematic diagram of Embodiment 3 of the series compensation circuit of the gradient amplifier provided by the present invention.

[0089] The series compensation circuit of the gradient amplifier provided in this embodiment further includes: a first switch S1 and a second switch S2;

[0090] Both ends of the first switch S1 are respectively connected to the positive output terminal and the negative output terminal of the first inverter 100;

[0091] Both ends of the second switch S2 are respectively connected to the positive output terminal and the negative output terminal of the second inverter 200;

[0092] When the first inverter 100 fails, the first switch S1 is closed;

[0093] When the second inverter 200 fails, the second switch S2 is closed.

[0094] It can be understood that when both the first inverter 100 and the second inverter 200 are normal, V1 and V2 are connected in series to provide power to the gradient coils. However, w...

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Abstract

The invention provides a series compensation circuit of a gradient amplifier and nuclear magnetic resonance imaging equipment. The series compensation circuit comprises a first boosting transformer and at least two following inverters, wherein the two inverters are a first inverter and a second inverter respectively; the first inverter is used for inverting first DC voltage into first AC voltage; the second inverter is used for inverting the second DC voltage and then inputting the second DC voltage into an input end of the first boosting transformer; the first boosting transformer is used for boosting the voltage of the input end into second AC voltage; the first AC voltage and the second AC voltage are superposed and then a power supply is provided for a gradient coil. The boosting transformer can boost the voltage, so that the circuit meets the requirements of the gradient coil in the next generation of nuclear magnetic resonance imaging equipment on high voltage. Normal withstand voltage is selected as the withstand voltage of switch tubes in the first inverter and the second inverter, and the switch tube with a very high withstand voltage grade does not need to be selected, so that model selection of the switch tubes is facilitated, or else, a model selection difficulty of the switch tubes is caused.

Description

technical field [0001] The invention relates to the technical field of medical equipment, in particular to a series compensation circuit of a gradient amplifier and nuclear magnetic resonance imaging equipment. Background technique [0002] The main function of the gradient amplifier is to provide driving current for the gradient coil in the nuclear magnetic resonance equipment, and it can precisely control the current of the gradient coil. The gradient coil can be equivalently understood as an inductance, so when the coil current changes rapidly, the gradient amplifier needs an instant Output high voltage; when the coil current is DC, the gradient amplifier needs to quickly change from a high voltage to a low voltage. [0003] Currently, gradient amplifiers use a series H-bridge topology to meet the requirements of MRI. For details, please refer to Figure 1a and Figure 1b , which is a schematic diagram of a series H-bridge gradient amplifier provided in the prior art. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/5387A61B5/055
CPCA61B5/055H02M7/5387
Inventor 林应锋
Owner NEUSOFT MEDICAL SYST CO LTD