| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive in which overload of an inverter can be prevented while ensuring power performance. <P>SOLUTION: When overload state of an AC motor is detected, a controller performs drive control of the motor to output a maximum torque T_max intermittently every predetermined period dt. Consequently, output torque T of the AC motor repeats such a pattern as it decreases to a sustainable torque T_std after exhibiting the maximum torque T_max for the predetermined period dt. The controller counts the number of times when the AC motor output the maximum torque T_max and when a decision is made that the count has reached a preset predetermined number N of permission, controls the AC motor to stop intermittent output of the maximum torque T_max and to deliver output torque reduced gradually from the maximum torque intermittently. Since the maximum torque T_max is utilized effectively within a range where the element temperature of the inverter does not reach an allowable temperature Th_lim, power performance of the motor is ensured. <P>COPYRIGHT: (C)2007,JPO&INPIT |
