| 摘要 |
PROBLEM TO BE SOLVED: To operate an induction motor with high efficiency and energy saving by making input power of the induction motor adaptive to a load factor of the induction motor at all the time.SOLUTION: In a load follow-up control device 18, an operation load factor is acquired in real time by units 9 and 8 for calculating the load factor, a power factor PF is acquired by a power factor PF calculation 4 and a reactive current Is is acquired by an Is calculation algorithm 5, respectively. A controlled variable Isk of the reactive current is calculated by reactive current Is minimization control 2 and a controlled variable PFk of the power factor is calculated by PF control 3, respectively. A frequency (rotational speed) controlled variable Fq is inputted to a variation V/F calculation algorithm 6 by a V/F setter 1 and an optimal voltage controlled variable Ud is calculated. In accordance with the optimal voltage controlled variable Ud and the frequency (rotational speed) controlled variable Fq, a waveform of SPWM generation 7 is adjusted and input power of an induction motor 17 is automatically regulated to a minimum value in an energy saving state with high efficiency by a power regulation unit 14.SELECTED DRAWING: Figure 6 |
