交流变频调速系统中的能量反馈控制

Feedback Control of Energy in AC Variable Frequency Speed Governing System

在大、中型变频调速系统中，能耗制动已不足取。采用回馈能量的电磁制动可以达到节能的目的，而且，若能控制回馈电流大小，还可以灵活地调节制动转矩，达到精密制动。本文介绍采用有源逆变电路使直流电能回馈给交流电源，其途径是从电网取得控制信号，保证了有源逆变电路各晶体管导通规律，得以使逆变之交流电压和电网电压同步。同时，在逆变电路中，采用斩波电流控制，达到灵活控制回馈电流亦即制动转矩大小的目的。

Inlarge ormedlum variable frequency speed governingsystem,the braking with energy loss has been replaced by the magnetic braking with energy feedback because the later has good flexibility and precision and caneconomize on energy.In this paper,the line commutated inverting circuit is adopted to feed the DC power energy back to the AC power supply by the method of gettingcontrol signals from the electric netwith the network voltage.Meanwhile,the modeof wave- cutting current control is adopted to sensitively control the feedback currem and the braking torque in the inverting circuit.