US 6,492,788 B1 · Method and apparatus for encoderless operation of a permanent magnet synchronous motor in an elevator

Abstract

A permanent magnet synchronous motor is controlled using d-axis current and q-axis current along with respective d-current and q-current feedback loops. The speed and position of the motor are determined by injecting a first signal into the d-axis current and observing the response in the q-current feedback loop. Part of the q-current feedback signal is demodulated with a second signal which is 90 degrees out of phase from the first signal. The demodulated signal is preferably sent through a low pass filter before being received by an observer controller. The observer controller outputs a position estimate which is used to modify the d-current feedback signal and a speed estimate which is used to modify the q-axis current.

Claims20

Dependent claims

Apparatus for determining speed and position of a permanent magnet synchronous motor, comprising:

d-axis current means for providing d-axis current to said motor;
said d-axis current means including a d-current feedback loop;
q-axis current means for providing q-axis current to said motor;
said q-axis current means including a q-current feedback loop;
means for injecting a first signal into said d-axis current means;
position estimating means for measuring current feedback responsive to said injected first signal to determine an estimated position of said motor;
speed estimating means for measuring current feedback responsive to said injected first signal to determine an estimated speed of said motor;
sensing means for sensing currents in 3-phase control signals controlling said motor;
first transformation means for transforming said sensed currents to 2-phase stationary frame signals;
second transformation means for transforming said stationary frame signals to synchronous frame signals;
and
an observer controller receiving input from said q-current feedback loop and providing a position estimate to second transformation means.

9 more elements

Apparatus for determining speed and position of a permanent magnet synchronous motor, comprising:

d-axis current means for providing d-axis current to said motor;
said d-axis current means including a d-current feedback loop;
q-axis current means for providing q-axis current to said motor;
said q-axis current means including a q-current feedback loop;
means for injecting a first signal into said d-axis current means;
position estimating means for measuring current feedback responsive to said injected first signal to determine an estimated position of said motor;
speed estimating means for measuring current feedback responsive to said injected first signal to determine an estimated speed of said motor;
an observer controller receiving input from said q-current feedback loop and providing a speed estimate to said q-axis current means;
sensing means for sensing currents in 3-phase control signals controlling said motor;
first transformation means for transforming said sensed currents to 2-phase stationary frame signals;
second transformation means for transforming said stationary frame signals to synchronous frame signals;
and
said observer controller providing a position estimate to second transformation means.

10 more elements

A method for determining speed and position of a permanent magnet synchronous motor, comprising the steps of:

providing d-axis current to said motor, including providing a d-current feedback loop;
providing q-axis current to said motor, including providing a q-current feedback loop;
injecting a first signal into said d-axis current outside of said d-current feedback loop;
measuring current feedback responsive to said injected first signal to determine an estimated position of said motor;
measuring current feedback responsive to said injected first signal to determine an estimated speed of said motor;
receiving input from said q-current feedback loop;
providing a speed estimate based on said input from said q-current feedback loop;
combining said speed estimate with a reference frequency to be used in the step of providing q-axis current;
sensing currents in 3-phase control signals controlling said motor;
transforming said sensed currents to 2-phase stationary frame signals;
transforming said stationary frame signals to synchronous frame signals;
and
providing a position estimate, based on input from said q-current feedback loop, to be used in the step of transforming said stationary frame signals to synchronous frame signals.

10 more elements

Dependencies are inferred from the claim text.

Method and apparatus for encoderless operation of a permanent magnet synchronous motor in an elevator

Life of this patent

Method and apparatus for encoderless operation of a permanent magnet synchronous motor in an elevator

Life of this patent

Abstract

Claims20