System and method for stabilizing a voice coil

Patent metadata

Field	Value
Publication number	US-9712033-B2
Application number	US-201514869815-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Sep 30, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A device or method for stabilizing a voice coil is disclosed. The device comprises a voice coil for providing a motive force, and means for measuring a signal from said voice coil related to a motional electromotive force. The device further comprises a unit for controlling an amplification of said signal to create a force in said voice coil in a direction of said motional electromotive force.

First claim

The invention claimed is:

1. A device for stabilizing a voice coil that controls a respiration valve in a medical device, comprising:
a voice coil for providing a motive force;
means for measuring an error signal from said voice coil related to a motional electromotive force, said error signal being based on a difference between a measured signal and an estimated or calculated steady-state signal; and
a unit for controlling an amplification of said signal to create and induce an adjustable damping force in said voice coil in a direction of said motional electromotive force.

2. The device according to claim 1 , wherein said error signal is measured by measuring a current through said voice coil.

3. The device according to claim 2 , wherein a sense resistor is connected in series with said voice coil to measure a voltage, said current is calculated based on said voltage and a resistance of said sense resistor.

4. The device according to claim 2 , wherein said error signal is a current error based on a difference between an estimated or calculated current in steady state and a measured current when said voice coil or associated magnet moves.

5. The device according to claim 4 , wherein said current error is amplified by changing said set voltage resulting in a change of said current through said voice coil.

6. The device according to claim 5 , wherein said error signal is a voltage error based on a difference between a measured or estimated voltage across said voice coil in steady state and a measured voltage when said voice coil or an associated magnet moves.

7. The device according to claim 6 , wherein said voltage error is amplified by changing said set current resulting in a change of said voltage across said voice coil.

8. The device according to of claim 1 , wherein controlling a set voltage to said voice coil controls said amplified signal.

9. The device according to claim 1 , wherein said error signal is measured by measuring a voltage across said voice coil.

10. The device according to claim 1 , wherein controlling a set current to said voice coil controls said amplified signal.

11. The device according to claim 1 , wherein said controlling of said amplified signal is performed directly or by a pulse-width modulator.

12. The device according to claim 1 , wherein a negative gain is used to cancel out or lessen effects of inherent motional electromotive force in said voice coil.

13. The device according to claim 1 , wherein a high-pass filter is used to remove DC and low frequency components before amplification of said error signal.

14. The device according to claim 1 , wherein said voice coil is arranged to drive said voice coil motor.

15. A method of stabilizing a voice coil, comprising: measuring an error signal related to a motional electromotive force of a voice coil, said error signal being based on a difference between a measured signal and an estimated or calculated signal in steady state; controlling an amplification of said signal to create and induce an adjustable damping force in said voice coil in a direction of said motional electromotive force.

16. The method according to claim 15 , wherein said error signal is a current error based on a difference between an estimated or calculated current in steady state and a measured current when said voice coil or an associated magnet moves, or wherein said error signal is a voltage error based on a difference between an estimated or calculated voltage in steady state and a measured voltage when said voice coil or an associated magnet moves.

Assignees

• Mindray Medical Sweden Ab
• Shenzhen Mindray Biomedical Electronics Co Ltd

Inventors

• Eklund Mathias
• Cewers Göran

Classifications

• H02P25/034

  Voice coil motors (voice coil motors driven by DC H02P7/025) · CPC title

• F16K31/06

  using a magnet {, e.g. diaphragm valves, cutting off by means of a liquid} · CPC title

• F16F15/02

  Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems ({F16F15/005 takes precedence } ; layered products B32B; suppression of vibration in ships B63; {relieving load on bearings, using magnetic means F16C39/06}) · CPC title

• H02P25/028

  with four quadrant control · CPC title

• A61M16/20 Primary

  Valves specially adapted to medical respiratory devices · CPC title