| 摘要 |
PURPOSE:To safely and effectively actuate the regenerative braking by a method wherein a commutation allowance angle of a thyristor circuit is detected, and if if the allowance angle approaches to such a value as causes a commutation failure, a control phase angle is controlled to make the commutation allowance angle larger. CONSTITUTION:Since the commutation allowance angle delta0 detected by a detection device 15 is larger than a reference signal 18 in the range of a large control phase angle gamma, a comparison device 21 feeds no signal 22. If the signal 22 is fed as an output when the control phase angle is reduced and the commutation allowance angle delta0 becomes smaller than the reference signal 18, a control input of a magnetic phase shifter 23 becomes a difference between the signals 20 and 22, a magnetic phase shifter output 24 tends to take the control phase angle gamma large and the commutation allowance angle deltao increases to act so as to prevent the commutation failure from being caused before it decreases below a critical value. |
