Switching type power source device and magneto-resonance imaging device using the same

Abstract

A switching type power source device used for magnetic field generation coils for an MRI device in which a switching power sources ( 9-11 ) are constituted by a first and a second multi level PWM inverter ( 12,13 ) having a same number of potential levels connected in parallel each other with respect to magnetic field generating coils ( 6-8 ) for the MRI device working as a load as well as a switching control circuit ( 19 ) for drive controlling the first and the second multi level PWM inverter ( 12,13 ) is constituted to drive control the first and the second multi level PWM inverter ( 12,13 ) in a manner to shift the switching phases thereof each other, thereby, ripple components in currents output from the first and the second multi level PWM inverter ( 12,13 ) are canceled out each other and a current with a further reduced ripple components as a whole can be supplied to the load ( 6-8 ).

Description

technical field [0001] The present invention relates to switching power supply equipment suitable for coils for magnetic field generation, that is, for magnetic resonance imaging equipment (hereinafter referred to as MRI equipment), a coil for generating a gradient magnetic field or a high-frequency magnetic field, and an MRI equipment using it. Background technique [0002] Switching power supplies have been widely used as power supply equipment for MRI equipment. Recently, in order to meet the demand for increased current, power supply equipment for coils for magnetic field generation in MRI equipment is constructed by connecting two stages of PWM inverters in parallel, as in JP-A -8-211139 as disclosed. Also, in the field of inverter power supplies for driving three-phase motors, multilevel inverter technology is used to boost voltage and boost current and measure higher harmonic components in the opposite direction, as in Jose Rodriguez et al. "Multilevel Inverters: A ...

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