Apparatus with motor winding resistance measurement and method for controlling such an apparatus

• US 10,065,001 B2
• Filed: 10/30/2014
• Issued: 09/04/2018
• Est. Priority Date: 10/30/2013
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Inventors: Nessel, Christian, Yates, Barry, Moore, David
• Primary Examiner(s): Chan, Kawing
• Application Number:
  US15/031,663
• Publication Number:
  US 20160263331A1
• Time in Patent Office: 1,405 Days
• Field of Search: 31856816
• CPC Class Codes: A61M 2005/31588 electrically driven
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3372 Temperature compensation
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/2448 comprising means for injection of two or more media, e.g. by mixing
• CPC Class Codes: A61M 5/31546 Electrically operated dose setting, e.g. input via touch screen or plus/minus buttons
• CPC Class Codes: A61M 5/31576 Constructional features or modes of drive mechanisms for piston rods
• CPC Class Codes: H02P 8/12 Control or stabilisation of current

Abstract

The invention relates to an apparatus, in particular for ejecting a fluid, having an electric motor (500), the motor comprising at least one motor winding (506a-d), having a control unit (656) for controlling the motor (500), wherein the apparatus further comprises an electronic detection circuitry (620) configured to determine an electrical quantity, the electrical quantity being a function of the electric resistance (Rw) of the motor winding (506a-d), and wherein the control unit (656) is configured to control the motor (500) as a function of the electrical quantity. The invention further relates to a method for controlling such an apparatus, comprising the steps of: determining an electrical quantity, the electrical quantity being a function of the electric resistance (Rw) of the motor winding (506a-d); and controlling the motor (500) as a function of the electrical quantity.

Claims

1. An apparatus for ejecting a fluid, the apparatus comprising:

an electric motor comprising at least one motor winding;

a control unit for controlling the motor; and

an electronic detection circuitry configured to determine an electrical quantity, the electrical quantity being a function of the electric resistance (R_w) of the motor winding, wherein the control unit is configured to control the motor as a function of the electrical quantity, wherein the electronic detection circuitry comprises an analogue digital converter configured to convert the electrical quantity from an analogue signal to a digital signal, wherein the analogue digital converter has a discrete number range of possible outputs and wherein the analogue digital converter is configured such that a middle number of the number range is output for an analogue signal of the electrical quantity for a motor winding temperature between 10°

C. and 40°

C.

2. The apparatus according to claim 1,

wherein the electric motor is a DC motor, and

wherein the apparatus comprises a DC voltage source configured to supply a voltage to the at least one motor winding.

3. The apparatus according to claim 2, wherein the DC motor is a DC stepper motor.

4. The apparatus according to claim 1, wherein the electrical quantity is a voltage.

5. The apparatus according to claim 1, wherein the detection circuitry comprises:

a first sub-circuitry configured to provide a first voltage being a function of a first voltage drop over the motor winding; and

a second sub-circuitry configured to provide a second voltage being a function of a voltage source, the voltage source being configured to supply voltage to the motor winding,

wherein the electrical quantity is a function of the difference between the first and the second voltage.

6. The apparatus according to claim 5,

wherein the detection circuitry comprises a differential amplifier having two input terminals and an output terminal,

wherein the first sub-circuitry comprises a first voltage divider connected in parallel to the motor winding, a central tap of the first voltage divider being connected to a first of the two input terminals of the differential amplifier, and

wherein the second sub-circuitry comprises a second voltage divider connected in parallel to the voltage source, a central tap of the second voltage divider connected to a second of the two input terminals of the differential amplifier.

7. The apparatus according to claim 1, further comprising:

a pulse width modulation (PWM) circuitry configured to control the motor torque by pulse width modulation, wherein the control unit is configured to control the PWM duty cycle as

a function of the electrical quantity.

8. The apparatus according to claim 1, wherein the control unit is configured to estimate the temperature of the at least one motor winding as a function of the electrical quantity.

9. The apparatus according to claim 1, wherein the control unit is configured to control the electronic detection circuitry to determine the electrical quantity when the motor is at rest.

10. The apparatus according to claim 1, wherein the apparatus is a medical device.

11. The apparatus according to claim 10, wherein the medical device is a medicament injection device.

12. The apparatus according to claim 1, wherein the apparatus is hand-held.

13. A method for controlling an apparatus, wherein the apparatus comprises:

an electric motor comprising at least one motor winding;

a control unit for controlling the motor; and

an electronic detection circuitry comprising an analogue digital converter configured to convert the electrical quantity from an analogue signal to a digital signal, wherein the analogue digital converter has a discrete number range of possible outputs and wherein the analogue digital converter is configured such that a middle number of the number range is output for an analogue signal of the electrical quantity for a motor winding temperature between 10°

C. and 40°

C.,

wherein the method comprises;

determining an electrical quantity, the electrical quantity being a function of the electric resistance (R_w) of the motor winding, the electrical quantity received as an analogue signal;

converting the analogue signal into a digital signal; and

controlling the motor as a function of the digital signal.

14. The method according to claim 13, wherein the electrical quantity is determined when the motor is at rest.