| 摘要 |
PURPOSE:To reduce power loss in case of regeneration, and to obtain stable regenerative operation by controlling regenerative power in response to regenerative power detected by deviation between the phase difference of voltage and currents at the input terminal of a motor during regenerative operation and reference phase difference. CONSTITUTION:The phase difference of motor currentsIM to motor voltage VM is largely delayed on a regenerative mode of the motor 3. The waveforms of voltage VM and currentsIM are shaped (c,e) into rectangular-wave signals by comparators 13A, 13B, the phase of voltage VM is shifted (d) to phase curresponding to reference phase difference by a phase shifter 14, and a phase difference signal (f) is obtained by a phase difference detector 15. The phase difference signal integrated by an integrator 16 is converted into a signal VD, converted into a signal VF by a V-F converter 17, and counted by a counter 18. When count value reaches set value, a regenerative control signal (i) is outputted, and a semiconductor switch is turned ON. Regenerative currents to load 6 for regeneration are increased. |
