| US 7,508,153 B2 | ||
| Method and device for determining the rotary speed of an electrical machine | ||
| Matthias Schanzenbach, Eberstadt (Germany); and Juergen Hachtel, Moeckmuehl (Germany) | ||
| Assigned to Robert Bosch GmbH, Stuttgart (Germany) | ||
| Filed on Dec. 05, 2006, as Appl. No. 11/634,445. | ||
| Claims priority of application No. 10 2005 059 585 (DE), filed on Dec. 14, 2005. | ||
| Prior Publication US 2007/0140669 A1, Jun. 21, 2007 | ||
| Int. Cl. G05B 11/28 (2006.01) | ||
| U.S. Cl. 318—599 [318/811; 388/928.1] | 19 Claims |
| 1. A method for determining a rotary speed of an electrical machine, which is controlled in PWM operation, the method comprising:
ascertaining the rotary speed from a tracking voltage, which is measured in a turnoff phase;
estimating the rotary speed in the PWM phase with the aid of a mathematical model, wherein the rotary speed is ascertained
in the PWM phase with the aid of a recursive function
ωi=ωi−1+Δω, where Δω=f(Uk,ωi−1);
and
controlling the electrical machine using a control signal, which has a PWM phase in which the electrical machine is periodically
switched on and off using a prespecified pulse duty factor, and which has a measuring phase in which the electrical machine
is switched off and the tracking voltage is measured.
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