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Control apparatus for electric motor

  • US 6,696,812 B2
  • Filed: 09/20/2001
  • Issued: 02/24/2004
  • Est. Priority Date: 04/11/2001
  • Status: Expired due to Term
First Claim
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1. A control apparatus for a motor that controls a voltage applied to an AC motor from a power converter by a PWM signal, wherein the control apparatus for the motor estimates a rotor magnetic pole position of the AC motor with at least two different magnetic pole position-estimating methods, estimates the rotor magnetic pole position of the AC motor with selectively switching the at least two magnetic pole position-estimating methods according to an operating state of the AC motor throughout an operating range of the AC motor,wherein, when the at least two magnetic pole position-estimating methods are switched, a rotor magnetic pole position of the AC motor is calculated on the basis of an operating state of the AC motor in a predetermined period.

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