Vacuum pump
AssigneeShimadzu Corporation
InventorJunichiro KOZAKI
Life of this patent
Estimating the term…
Abstract
An estimating section detects a signal including counter electromotive voltage information of the motor, and estimating a magnetic pole electric angle and a rotational speed of the motor. A driving current controller repeats generation and cut-off of the driving current supplied from a power supply to the motor via the inverter circuit or regenerated from the motor to the power supply in a low-speed period between a stopped state and a predetermined rotational speed in an accelerating operation at a motor starting time or a decelerating operation at a motor stopping time. The estimating section detects the signal at the cut-off time so as to estimate the magnetic pole electric angle and the rotational speed in the low-speed period.
Claims9
A vacuum pump comprising:
- a motor for driving to rotate a pump rotor;
- a sine wave driving command generating section for generating a sine wave driving command;
- a PWM driving command generating section for generating a PWM driving command based on the sine wave driving command;
- an inverter circuit, having a plurality of switching elements controlled to be on/off based on the PWM driving command, for supplying, to the motor, a driving current to be generated by turning on/off the plurality of switching elements or regenerating the driving current from the motor;
- an estimating section for detecting a signal including counter electromotive voltage information of the motor, and estimating a magnetic pole electric angle and a rotational speed of the motor;
- and
- a driving current controller for repeating generation and cut-off of the driving current supplied from a power supply to the motor via the inverter circuit or regenerated from the motor to the power supply in a low-speed period between a stopped state and a predetermined rotational speed in an accelerating operation at a motor starting time or a decelerating operation at a motor stopping time, wherein
- the estimating section detects the signal at the cut-off time so as to estimate the magnetic pole electric angle and the rotational speed in the low-speed period.
Dependencies are inferred from the claim text.