US 6,204,627 B1 · Motor control apparatus

Abstract

A transformer outputs different (high or low) secondary voltages. A switch outputs high or low secondary voltage according to a mode signal. An electric power converter including a rectifying circuit and a switching circuit either charges a smoothing capacitor with an output of the switch or discharges the smoothing capacitor to supply a regenerative current toward the transformer with a power fact improved. An phase signal generation circuit generates PWM or PAM phase signals in accordance with the mode signal. An inverter circuit generates driving signals supplied to the motor in response to the phase signals from power from the smoothing capacitor. A mode determining circuit determines one of modes to generate the mode signal in accordance with a speed command signal and acceleration/deceleration which is indicated by the rotating speed signal and the rotating speed command signal.

Claims16

Dependent claims

A motor control apparatus for a centrifugal apparatus comprising:

an ac power source;
a transformer for converting a voltage of said ac power source;
an electric power converter connected to said transformer;
a smoothing capacitor;
power factor improving control means for controlling said electric power converter and adjusting a charge voltage of said smoothing capacitor;
an inverter converter for a motor connected to said smoothing capacitor;
switching means provided between a plurality of secondary voltage taps provided to said transformer and said electric power converter for switching among a plurality of secondary voltage taps;
and
inverter control means for controlling said inverter converter for said motor and switching between the pulse width modulation controlling and the pulse amplitude modulation.

6 more elements

A motor control apparatus for controlling a motor comprising:

a transformer for receiving an ac power and outputting different secondary voltages;
a switch for outputting one of different secondary voltages in accordance with a mode signal;
a smoothing capacitor;
an electric power converter including a rectifying circuit and a switching circuit for either charging said smoothing capacitor with an output of said switch or discharging said smoothing capacitor to supply a regenerative current from said motor to said transformer to control a voltage of said smoothing capacitor in accordance with said mode signal;
power factor improving means for controlling said electric power converter, adjusting a voltage of said smoothing capacitor, and improving a power factor of said motor control apparatus;
rotating speed detection means for detecting a rotating speed and a position of said motor to generate a rotating speed signal;
drive signal generation means including a pulse width modulation circuit and a pulse amplitude modulation circuit for generating either of first phase signals by said pulse width modulation circuit or second phase signals by said pulse amplitude modulation circuit in accordance with said mode signal, pulse widths of said first phase signals being controlled by said pulse amplitude modulation circuit in accordance with said rotating speed command signal and said rotating speed signal such that a difference between said rotating speed command signal and said rotating speed is reduced, said second phase signals being generated by said pulse amplitude modulation circuit such that a slip frequency between said second phase signals and rotation of a rotor of said motor is controlled in accordance with said rotating speed command signal and rotating speed signal;
an inverter circuit for generating driving signals supplied to said motor in response to an output of said drive signal generation means with power from said smoothing capacitor;
and
mode determining means for determining one of modes to generate said mode signal in accordance with a speed command signal and said rotating speed signal.

7 more elements

Dependencies are inferred from the claim text.

Motor control apparatus

Life of this patent

Motor control apparatus

Life of this patent

Abstract

Claims16