Current-inverting power source of speed control in deceleration period of AC hoist in mines

The requirement of speed in deceleration and low-speed-drive period of AC hoist and some problems in equipment are introduced in the paper.It presents a new technique of AC-DC-DC current-inverting project to resolve the problem of dynamic braking power source, and AC-DC-AC frequency-variable power source to resolve the problem of requirement of low speed drive. Describing the structure of system, the authors analyze the theory of control circuits. At last its structure of control software and main-program flow diagram are given here.