High-bandwidth high-power gradient driver for magnetic resonance imaging with digital control

Sabate, Juan; Garces, Luis; Szczesny, P.M.; Wirth, W.F.

doi:10.1109/apec.2005.1453131

Cited by 14 publications

(9 citation statements)

References 10 publications

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“…Inverters' ripple currents i Con1 and i Con2 can be shifted by phase, and ripple frequency of load current i Load can be increased, by applying interleave control 5,8 to each of two unit modules connected in parallel in SiC inverter. Therefore, one can expect that ripple current specifications are achieved due to interleave control, even at a reduced carrier frequency.…”

Section: Application Of Interleave Controlmentioning

confidence: 99%

“…4 In addition, slew rate over 1 A/μs is necessary for rapid formation of magnetic field. 3,5,7,8 There are techniques to output ripple current at a frequency sufficiently higher than carrier frequency to suppress ripple current superimposed on load current; parallel multi-inverters [4][5][6] and series multi-inverters 3,7 are employed in gradient drivers for this purpose. In Reference, 5 a four parallel-connected inverter is used to suppress ripple current by setting its principal component to quadruple carrier frequency (80 kHz).…”

Section: Introductionmentioning

confidence: 99%

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A proposal of a new gradient driver with a gradational voltage inverter for low power loss

Oishi

Kobayashi

Sakashita

2022

Electrical Engineering Japan

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This paper proposes a new gradient driver with a gradational voltage inverter for low power loss and downsized filter circuits. Gradient drivers produce direct current with low ripple amplitudes to achieve high image quality and high slew rates to obtain images rapidly. The proposed gradient driver is characterized by low ripple amplitude of the output current from the inverter composed of SiC‐MOSFETs and high output voltage from another inverter composed of IGBTs. This paper discusses both the principle of operation and control method of the new gradient driver. Experimental verification is performed on a full‐scale system. The results show the advantages of the proposed gradient driver based on loss analysis by calculations.

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Section: Application Of Interleave Controlmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A proposal of a new gradient driver with a gradational voltage inverter for low power loss

Oishi

Kobayashi

Sakashita

2022

Electrical Engineering Japan

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“…As the proposed power supply get worse output performance than the one in [2], the amplifier control part mentioned in [6] should get some modifications to deal with the dc bus voltage variation caused by load change.…”

Section: Gradient Amplifier Control Modificationmentioning

confidence: 99%

“…In practical system, the leakage of the multi-winding transformer should be designed as small as possible to get good voltage regulation performance and small cross-talking impact among the axes. Fig.9 presents the gradient amplifier [6] performance with the proposed power supply and control mentioned in Fig.6. The coil reference is trapezoidal EPI waveform and during the amplifier operation the dc bus voltage V350/650 will drop because of the power output.…”

Section: Gradient Amplifier Control Modificationmentioning

confidence: 99%

Multi-output power supply with series voltage compensation capability for Magnetic Resonance Imaging system

Zhu

Liu

Sabate

2009

2009 IEEE 6th International Power Electronics and Motion Control Conference

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In Magnetic Resonance Imaging system, the most powerful device is gradient driver, which is also one of the key components to realize fast imaging with high quality. To meet the requirements of high-end MRI products, the power rating of the gradient driver increase from several hundred-kVA to 1MVA and even higher in the future. Commonly the gradient driver applies full bridge cascade technology and needs a lot isolated DC source with high power capability. To provide solution to this requirement, several technology platforms have been developed. This paper presents one of the most attractive options. In the proposed power supply structure, an AC pre-regulator and a multi-winding transformer are combined together with diode rectifiers to provide multiple isolated DC outputs. The AC pre-regulator compensates the utility voltage variation by injecting voltage to the input line through a series transformer, and that make the multi-winding transformer get a stable input. With this solution, the DC outputs voltage is only determined by the transformer leakage inductance and load current. Compared with high frequency DC-DC conversion methods, this scheme does not need high frequency magnetic devices and capacitors, which are difficult to build and high cost for high power application. The switching devices (IGBTs) in this option can also operate at a much lower frequency (several kHz) to reduce the switching loss, and lower switching frequency also benefit the device selection. Beside that the rectifiers applied at the secondaries of the multi-winding transformer operate at line frequency and that benefits the device selection and cost too. Here in this paper, the control algorithm of the power supply is presented and discussed. Both its self-performance and co-operation with the amplifier are evaluated with Saber simulation. The results indicate the attractiveness of the proposed scheme.

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“…Solutions using parallel or stacked bridge structures have been reported [1][2][3][4][5][6][7][8]. The structure proposed in [9], as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

High performance gradient driver for magnetic resonance imaging system

Lai

Sabate

Chi

et al. 2011

2011 IEEE Energy Conversion Congress and Exposition

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In high performance magnetic resonance imaging (MRI) systems, the gradient driver is required to supply the gradient coil with large amplitude (>600A) and high slew rate (>2A/µs) current waveform. In addition, extremely high fidelity for reproducing the current command from the central system is very critical for imaging quality. This paper presents an improved gradient driver structure and a new modulation scheme, with which the switching frequency will vary according to the slew rate of the current command. The corresponding output filter design is also introduced. With the proposed technique the switching loss can be reduced and evenly distributed in all the bridges, therefore the utilization ratio of the semiconductor devices is improved and the number of devices in parallel can be reduced. A 2 MVA platform has been built and fully tested. The experimental results proved the validity of the proposed structure and modulation technique.

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High-bandwidth high-power gradient driver for magnetic resonance imaging with digital control

Cited by 14 publications

References 10 publications

A proposal of a new gradient driver with a gradational voltage inverter for low power loss

A proposal of a new gradient driver with a gradational voltage inverter for low power loss

Multi-output power supply with series voltage compensation capability for Magnetic Resonance Imaging system

High performance gradient driver for magnetic resonance imaging system

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