Claims
- 1. A method of driving a capacitive actuator, which comprises:
- charging a capacitive actuator with a charge voltage;
- calculating, from a charge quantity .DELTA.Q supplied to the actuator and from an actuator voltage U.sub.p applied to the actuator after the charging operation is terminated, an actuator capacitance by the equation C.sub.p =.DELTA.Q/U.sub.p ;
- calculating, from the actuator capacitance C.sub.p and the actuator voltage U.sub.p, an energy E.sub.actual supplied to the actuator during the charging step by the equation E.sub.actual =0.5*C.sub.p *U.sub.p.sup.2 =0.5*.DELTA.Q*U.sub.p ;
- comparing the energy E.sub.actual with a desired energy E.sub.setpoint ; and
- if the energy E.sub.actual is less than the desired energy E.sub.setpoint, increasing the charge voltage U.sub.L by a predetermined amount for a next charging operation; or
- if the energy E.sub.actual is greater than the desired energy E.sub.setpoint, decreasing the charge voltage U.sub.L by the predetermined amount for the next charging operation.
- 2. The method according to claim 1, which comprises determining the charge quantity .DELTA.Q supplied to the actuator by integrating the current I.sub.p flowing through the actuator during a charging operation according to the integration .DELTA.Q=.intg.I.sub.p dt.
- 3. The method according to claim 1, which comprises charging and discharging with a charging capacitor and a discharging capacitor connected in series, and applying a regulatable voltage to the charging capacitor, and determining the charge quantity .DELTA.Q supplied to the actuator by way of a difference .DELTA.U in voltages U.sub.before and U.sub.after present at the discharging capacitor before and after the charging operation, respectively, and ascertaining a capacitance C2 of the discharging capacitor by the equation .DELTA.Q C2*.DELTA.U=C2*(U.sub.before -U.sub.after).
- 4. The method according to claim 1, which comprises using the calculated actuator capacitance C.sub.p to determine an actuator temperature T.sub.p.
Priority Claims (1)
Number |
Date |
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Kind |
197 23 932 |
Jun 1997 |
DEX |
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CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of copending International Application PCT/DE98/01155, filed Apr. 24, 1998, which designated the United States.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
4688536 |
Mitsuyasu et al. |
Aug 1987 |
|
5387834 |
Suzuki |
Feb 1995 |
|
5543679 |
Morina et al. |
Aug 1996 |
|
6016040 |
Hoffmann et al. |
Feb 2000 |
|
Foreign Referenced Citations (4)
Number |
Date |
Country |
0611881A1 |
Aug 1994 |
EPX |
3621541A1 |
Jan 1987 |
DEX |
05029676 |
Feb 1993 |
JPX |
05344755 |
Dec 1993 |
JPX |
Continuations (1)
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Number |
Date |
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Parent |
PCTDE9801155 |
Apr 1998 |
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