Acceleration controller for laundry machine motor
AssigneeFisher & Paykel Limited
InventorDavid J. Ensor
Life of this patent
Estimating the term…
Abstract
A method of cyclically accelerating an electric motor particularly for use in a laundry machine. A desired speed, direction of rotation and acceleration time is set and power is applied to the motor in a series of incremental steps, each successive step corresponding to an increase in the level of power applied during the previous step. The steps are initially estimated to be sufficient to enable sufficient energy to be supplied to the motor for it to reach the desired speed in the desired acceleration time. The speed of the motor is monitored and the steps of accelerating the motor are repeated with the series of incremental steps adjusted to adjust the supply of energy to the motor dependant on the speed reached in the acceleration time of the previous cycle.
Claims14
An electronic control means for cyclically controlling the supply of power to an electric motor having a rotor and a stator to perform cycles of accelerating said rotor to a maximum speed and bringing said motor to rest, said control means including
- a. power supply means provided to supply power to said motor at a desired rate;
- b. speed setting means operable to set a desired speed of rotation of said rotor and a desired acceleration time for said motor from rest to said desired speed;
- c. incremental step setting means to set an initial series of incremental steps, each successive step corresponding to an increase in the level of power supplied to said motor over the level of power supply reached in the previous step, said steps being estimated to be sufficient to enable sufficient energy to be supplied to said motor to reach said desired speed in said acceleration time;
- d. speed determining means to determine the speed of said motor;
- e. switching means to switch off the power supply to said motor;
- f. adjusting means responsive to control signals from said speed determining means to adjust the number and/or size of said incremental steps to adjust the supply of energy to said motor to adjust the acceleration and thereby change said motor speed towards said desired speed during a next cycle of operations.
Dependencies are inferred from the claim text.