Motor control device

A device for controlling an AC motor, comprising:

• an electric power inverter which applies a voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals in synchronism with carrier waves;
• wherein the motor control device further comprises a position estimation unit which estimates a position of a rotor of the AC motor through shifting the PWM signals within one cycle of the carrier waves from current variation amount of the AC motor.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies a voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals in synchronism with carrier waves;
• wherein the motor control device further comprises a current variation amount detection unit which detects current variation amount of the AC motor for every predetermined time in synchronism with the carrier waves and a position estimation unit which estimates a rotor position of the AC motor from a relationship between a plurality of the current variation amounts and a plurality of the applied voltages corresponding thereto.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies a voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWIVL signals in synchronism with carrier waves;
• wherein the motor control device further comprises a voltage addition unit which adds a detection use voltage in a direction of estimated magnetic pole position (d-axis) in synchronism with the carrier waves, a current variation amount detection unit which detects current variation amount of the AC Motor for every predetermined time in synchronism with the carrier waves and a position estimation unit which estimates a rotor position of the AC motor from a plurality of the current variation amounts.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals;
• wherein the motor control device further comprises a position estimation unit which estimates a position of a rotor of the AC motor by applying applied voltages having different phases in vector, a plurality of times, and by detecting counter electromotive forces from current variation amounts of the AC motor for respective voltage applications.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals;
• wherein the motor control device further comprises a position estimation unit which estimates a position of a rotor of the AC motor by applying applied voltages having the same phase in vector and different magnitude, a plurality of times, and by detecting counter electromotive forces from the current variation amounts of the AC motor for the respective voltage applications.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals;
• wherein the motor control device further comprises a position estimation unit which estimates a position of a rotor of the AC motor by controlling phases of applied voltages so that a phase difference of the current variation amounts of the AC motor with respect to the applied voltages assumes either 0° or 180°.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals;
• wherein the motor control device further comprises a position estimation unit which estimates a position of a rotor of the AC motor by controlling applied voltages so that the current variation amounts of the AC motor with respect to the applied voltages assumes 0.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals;
• wherein the motor control device further comprises a current variation control unit which controls the voltage so that current variation amounts of the AC motor assumes a value of 0 in a predetermined section.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies a voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals;
• wherein the motor control device further comprises a phase shifting means which shifts the PWM signals within one cycle of carrier waves.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies a voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals in synchronism with carrier waves;
• wherein
• the motor control device further comprises a position estimation unit which estimates a position of a rotor of the AC motor based on a detection of current in the AC motor in synchronism with the carrier waves;
• and
• the PWM signals are shifted so that a section for detecting current assumes a 0 voltage vector state.

A device for controlling an AC motor, comprising:

• an electric power inverter which applies a voltage to the AC motor;
• and
• a control unit which controls the applied voltage with PWM signals in synchronism with carrier waves;
• wherein
• the motor control device further comprises a position estimation unit which estimates a position of a rotor of the AC motor based on a detection of current in the AC motor in synchronism with the carrier waves;
• and
• the rotor position is detected by controlling applied voltages so that a phase of a current variation amount difference vector coincides with a difference vector of the applied voltage.