초록 ▼

To provide a control system for a permanent magnet synchronous motor which can ensure stability of the current control system, even if the revolution frequency of the motor becomes higher and the terminal voltage of the motor exceeds the inverter maximum output voltage. In this method, when the revo

To provide a control system for a permanent magnet synchronous motor which can ensure stability of the current control system, even if the revolution frequency of the motor becomes higher and the terminal voltage of the motor exceeds the inverter maximum output voltage. In this method, when the revolution frequency of the motor exceeds a specified value, the size of the voltage vector is made a specified voltage vector, and a modulation factor based on its value is obtained. At the same time, a magnetic flux direction current correction value is found based on the size of a voltage vector from a polarity coordinates conversion unit and the above specified voltage vector size. Then, the magnetic flux direction current instruction is corrected by that value.

대표청구항 ▼

[ What is claimed is:] [1.] A control system which controls a permanent magnet synchronous motor via a power conversion system, comprising:a current instruction value operation unit having inputs including a torque instruction, an angular frequency of the motor and a magnetic flux direction current

[ What is claimed is:] [1.] A control system which controls a permanent magnet synchronous motor via a power conversion system, comprising:a current instruction value operation unit having inputs including a torque instruction, an angular frequency of the motor and a magnetic flux direction current correction value, and having outputs including a magnetic flux direction current instruction and a torque direction current instruction;a voltage instruction operation unit having inputs including the magnetic flux direction current instruction and the torque direction current instruction outputted by said current instruction value operation unit, and having outputs including a magnetic flux direction voltage instruction and a torque direction voltage instruction;a polar coordinates conversion unit having inputs including the magnetic flux direction voltage instruction and the torque direction voltage instruction outputted by said voltage instruction operation unit, and having outputs including a voltage vector size and a voltage vector angle to a magnetic flux axis direction;a voltage fixing unit having inputs including the voltage vector size outputted by said polar coordinates conversion unit, a voltage vector size instruction value and a voltage fixing instruction, and having an output including a fresh voltage vector size of one of the voltage vector size outputted by said polar coordinates conversion unit and the voltage vector size instruction value, said fresh voltage vector size is selected based on the voltage fixing instruction;a magnetic flux direction current correction value operation unit having inputs including the voltage vector size outputted by said polar coordinates conversion unit and the fresh voltage vector size outputted by said voltage fixing unit, and having an output including said magnetic flux direction current correction value;a modulation factor operation unit having inputs including the fresh voltage vector size outputted by said voltage fixing unit and a DC link voltage of said power conversion system, and having an output including a modulation factor of said power conversion system;a torque current control unit having inputs including the torque direction current instruction outputted by said current instruction value operation unit and a torque current actual value, and having an output including a torque angle correction value; anda PWM voltage generating unit having inputs including the modulation factor outputted by said modulation factor operation unit and a sum of the voltage vector angle outputted by said polar coordinates conversion unit, the torque angle correction value outputted by said torque current control unit and a permanent magnet magnetic flux angle, and having outputs including PWM voltage instructions for said power conversion system.