Hard Axis Of The Dual Motor Drive Frequency Variable Speed And Power Balance Control

With the fast development of industry, people have more and more need to every machine capability and product quality. Now, in some occasion with heavy and big spanning frame load, only control one motor cannot meet the need of industry modernization, but request people control multi-motor, make them work harmony. Multi-motor fixed joint driving systems are widely used in the field of hoisting, such as longmen crane, winch hoist, sluice and so on. Because of designing of machine, such load are not suitably drive only by one motor, but use two motors to drive on two sides of the load. In order to keep speed the same of the two motors when they are working, people usually coupling two motors through a rigid axis on engineer. But by the influences of material, manufacture crafts and manufacture precision, two motors' electrical parameters can not be completely equal. This will easily course to destroy motor by distributing unbalance of load to each motor during working. So research the theory and methods of synchronization driving of fixed joint two motors, has large actual significance to assuring save and reliable working of this machine.This paper takes background of driving equipment of Hydropower station planar sluice, aim to the characteristic of fixed joint two-motor, researched load distribution and power balance of two motors during synchronization driving. Paper start at the need of wording reliable, start and stop steady, opening preciseness of the sluice, had investigated the research status of two motors synchronization driving. Produced development process detail of variable frequency speed regulation, analyzed principle of speed sensorless vector control and direct torque control, and analyzed their machine capability. Combine the advantage of widely speed regulation, small steady-status error of vector control and fast response of direct torque control, take vector control and direct torque control into synchronization driving of two motors, give a novel host-slave control method: the host motor take vector control, speed and torque are closed loop, tracking the giving speed value; the slave motor's speed loop is open, tracking host motor's torque value. Because traditional direct control method has disadvantage of switch frequency not fixed of inverter, big pulsation of current and torque, bed capability in low speed and so on, in the paper, slave motor take the method of space vector modulation base on PI, resolve the problem of voltage vector amount limit in switch table, at the same time resolve the problem of switch frequency not fixed of inverter, make pulsation of current and torque lower, prove the capability in low speed. The simulation result indicated the system has good steady and dynamic performance, verified the rationality of this design.