公开(公告)号：US09780571B2

公开(公告)日：2017-10-03

申请号：US14471947

申请日：2014-08-28

Applicant: MOTOROLA SOLUTIONS, INC

Inventor： Edward W Brumley, Jr. ,  John E Herrmann ,  David W Wallis

IPC: H02J5/00 ,  H04B5/00 ,  H02J50/20 ,  H02J50/80

CPC classification number: H02J5/005 ,  H02J50/20 ,  H02J50/80 ,  H04B5/0037 ,  H04B5/0093

Abstract: Disclosed herein are methods and systems for providing a ballast load for a magnetic resonance power source. One embodiment takes the form of a magnetic resonance power source that includes a source coil, a load-detection module, a tunable ballast coil circuit, and a controller programmed to carry out a set of functions. The set of functions includes obtaining, via the load-detection module, an estimated load on the source coil. The set of functions also includes decreasing the power received by the tunable ballast coil circuit from the source coil when the estimated load on the source coil is greater than a desired load on the source coil. The set of functions also includes increasing the power received by the tunable ballast coil circuit from the source coil when the estimated load on the source coil is less than the desired load on the source coil.

公开(公告)号：US09231481B2

公开(公告)日：2016-01-05

申请号：US13871748

申请日：2013-04-26

Applicant: MOTOROLA SOLUTIONS, INC

Inventor： David W Wallis

IPC: H02M3/335 ,  H02J7/00 ,  H02J7/04 ,  H02M1/14 ,  H02M1/44 ,  H02M1/00

CPC classification number: H02M3/33507 ,  H02J7/0044 ,  H02J7/04 ,  H02M1/14 ,  H02M1/44 ,  H02M2001/0029

Abstract: A power converter having reduced switching transients includes a conversion inductance, a pulse width modulation (PWM) controller, a conversion inductance, and a switch transistor. A low pass filter is connected between the PWM controller and the switch transistor to filter a PWM signal produced by the PWM controller and produce a filtered PWM signal. The switching transistor switches current through the conversion inductance responsive to the filtered PWM signal. The low pass filter filters out harmonic content of the PWM signal that is above the fundamental frequency in a way that maintains most of the harmonic content of the PWM signal to substantially eliminate higher harmonic elements which are conventionally responsible for transients across the conversion inductance.

Abstract translation: 具有减小的开关瞬变的功率转换器包括转换电感，脉宽调制（PWM）控制器，转换电感和开关晶体管。 PWM控制器和开关晶体管之间连接有一个低通滤波器，以对由PWM控制器产生的PWM信号进行滤波，并产生滤波后的PWM信号。 开关晶体管响应于滤波的PWM信号而切换电流通过转换电感。 低通滤波器以维持PWM信号的大部分谐波含量的方式滤除高于基频的PWM信号的谐波含量，从而基本上消除了传统上负责转换电感瞬态的高次谐波元件。