The Research Of AC Motor Chop-wave Cascade Speed-regulation System Of Mine-well Hoist

Wound-rotor induction motors that adjust speed by connecting resistors in series to rotor circuits, have found a wide range of applications in the electrically controlled systems of mine-well hoists. This method regulates speed by changing the number of steps of the additional resistor in the rotor circuit, so it's hard to realize smooth speed-regulation, also its performance is poor. During the speed-regulating process, a great amount of slip power transforms to heat through rotor circuit resistor.This thesis presents utilizing chop-wave cascade speed-regulation system to reform wound induction motors that adjust speed by connecting resistors in series to rotor circuits. Compared with cascade speed-regulation system, the difference is that DC chopper is joined into rotor DC circuit. Chop-wave cascade speed-regulation system not only overcomes the disadvantages of step-speed-controlled, but also improves the system's performance by adopting close-loop control. Inverter capacity is decreased, the more important is that power factor is increased greatly.This paper investigates topology structure of main circuit, analyzes principle and induces mechanical characteristic of chop-wave cascade speed-regulation system. Then it presents selection of main circuit parameters and inverter capacity.Based on technical characteristic of mine-well hoists, IGCT is used to be chopper instead of thyristor, thus the chopping frequency can be increased one thousand Hz, and the disadvantage of thyristor's force-converter can be overcome, the economic benefit also can be raise with good quality.This paper uses TMS320LF2407A DSP processor as controller. It can achieve control functions and satisfy real-time control demands.At last using models in MATLAB and the system composed of these model, it realized the simulation. The result show that, it is a practical chop-wave cascade speed-regulation system.