Application of piezo technology to convert alternating current (AC) line power to isolated direct current (DC) power in high external magnetic fields

Patent metadata

Field	Value
Publication number	US-10096764-B2
Application number	US-201515108798-A
Country	US
Kind code	B2
Filing date	Jan 6, 2015
Priority date	Jan 6, 2014
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A system ( 10 ) and a method ( 200 ) supply power in high external magnetic fields. Alternating current (AC) line power is converted ( 202 ) to isolated power using one or more piezoelectric transformers ( 18 ). The flow of AC line power to the piezoelectric transformers ( 18 ) is regulated ( 204 ) to maintain the isolated power at a predetermined voltage.

First claim

The invention claimed is:

1. A power supply for supplying power in high external magnetic fields, the power supply comprising:
a piezoelectric core converter module configured for converting alternating current (AC) line power to isolated direct current (DC) power using one or more piezoelectric transformers; and
a regulator module configured for regulating the flow of AC line power to the piezoelectric core converter module to maintain the isolated power at a predetermined voltage;
wherein the regulator module includes a microcontroller module and a bias regulator module which provides a first regulated DC power sufficient to power the microprocessor module and a second regulated DC power;
wherein the piezoelectric core converter module includes an H-bridge module which receives the second regulated DC power from the bias regulator and generates a high frequency pulse train;

wherein a module determines a difference between the isolated DC power and an expected isolated DC power and the microcontroller controls the H-bridge module to adjust a duty cycle of the high frequency pulse train.

2. The power supply according to claim 1 , wherein the piezoelectric core converter module includes an air core inductor configured for generating from high frequency pulse train a sinusoidal input to the piezoelectric transformers at a frequency above the mechanical resonance of the piezoelectric transformers.

3. The power supply according to claim 1 , wherein the one or more piezoelectric transformers includes a plurality of piezoelectric transformers connected in parallel to increase power output of the power supply.

4. The power supply according to claim 1 , wherein the regulator module is further configured for:
monitoring the temperature of the piezoelectric transformers and/or monitoring the AC line power; and
protecting the piezoelectric transformers from damage based on the monitoring.

5. The power supply according to claim 1 , wherein the high magnetic field is greater than 2000 gauss (G).

6. A medical system comprising:
a magnetic resonance imaging (MRI) scanner including a main magnetic which generates a high external magnetic field; and
the power supply according to claim 1 positioned proximate to the main magnetic and providing power to an external load.

7. A method for supplying power in high external magnetic fields, the method comprising:
converting alternating current (AC) line power to isolated direct current (DC) power using one or more piezoelectric transformers; and
regulating the flow of AC line power to the piezoelectric transformers to maintain the isolated power at a predetermined voltage;
wherein the regulating includes providing a first regulated DC power; sufficient to power a microprocessor module and a second regulated DC power;
wherein the converting includes receiving the second regulated DC power and generating a high frequency pulse train;
wherein a difference between the isolated DC power and expected isolated DC power is determined and used by the microcontroller to adjust a duty cycle of the high frequency pulse train.

8. The method according to claim 7 , wherein the converting includes:
generating a sinusoidal input to the piezoelectric transformers at a frequency above the mechanical resonance of the piezoelectric transformers by an air core inductor.

9. The method according to claim 7 , wherein the regulating includes:
monitoring the temperature of the piezoelectric transformers and/or monitoring the AC line power; and
protecting the piezoelectric transformers from damage based on the monitoring.

10. The method according to claim 7 , further including:
positioning the piezoelectric transformers proximate a main magnetic of a magnetic resonance imaging (MRI) system, the main magnet generating the high external magnetic fields.

Assignees

• Koninklijke Philips Nv

Inventors

• Bailey Paul Wayne

Classifications

• H02M3/33523

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title

• H02M1/44

  Circuits or arrangements for compensating for electromagnetic interference in converters or inverters · CPC title

• G01R33/546

  Interface between the MR system and the user, e.g. for controlling the operation of the MR system or for the design of pulse sequences · CPC title

• G01R33/56

  Image enhancement or correction, e.g. subtraction or averaging techniques {, e.g. improvement of signal-to-noise ratio and resolution} · CPC title

• A61B2560/0214

  of power generation or supply · CPC title