| 摘要 |
PURPOSE: To promptly discharge electric charge from a main circuit capacitor by limiting a speed command for a motor to zero while an inverter is operated. CONSTITUTION: While a speed command of a motor is limited to zero, an operation command for an inverter is turned on, and interlock in inverter operation is canceled. Thus, a vector control voltage-type transistor inverter is operated with an operation command in a zero state, so the motor is operated with only an excitation current factor and no torque current factor in a primary current as an output current from the inverter. A core loss is caused by an excitation current in motor, but electric charge accumulated in a main circuit capacitor is discharged to consume electrostatic energy and compensate the core loss. Next, a discharging timer is always used to check whether a previously calculated discharge time elapses or not. As a result, the inverter and the motor are put continuously in zero-speed operation until the discharge from the capacitor is finished. |
