Key Technology Reasearch Of Explosion-Proof VFD Integration Motor

Coal mine explosion-proof VFD (Variable Frequency Drive) induction motor has the advantages of saving energy, low mechanical load and adjustable speed and torque comparing with traditional explosion-proof induction motor. The motor and converter of traditional VFD motor are discrete components. In the coal mine the motor is hundreds meters away from the switch cubicle, additionally, the work environment of the motor is complex. In order to maintain the motor normally running, reactors must be installed in the circuit; consequently, stability and reliability of the motor are reduced. This dissertation presents an explosion-proof VFD integration induction motor used in scraper conveyor. A series of key technological and design method for the explosion-proof VFD integration induction motor was formed.The contents of this dissertation can be divided into following parts.In the first part, the problems of loss, thermal field and cooling structure of the explosion-proof induction motor were studied. The seal performance of the explosion-proof induction motor shell is good, so it is hard for the explosion-proof induction motor to dissipate heat. The problem is even more serious for the explosion-proof VFD integration induction motor. This dissertation presents a new high strength type of water-cooling structure to adapt the high hydraulic pressure. The effectiveness of the design was proved by EMF analyze and the hydraulic pressure experiment.In the second part, an experiment to separate was presented, the temperature of rotor was measured and the loss of the rotor was calculated. A concept of quality for rotor loss and temperature was built. The3-D temperature of the explosion-proof VFD integration induction motor is calculated by using the finite element method. It is a powerful analytical tool in guiding the design of motor.In the third part, the EMI coupling path of the main power topology of the explosion-proof VFD integration induction motor speed control system was researched. In order to cut down the electric influence of IGBT, the suppression method is presented by breaking EMC coupling path. Theory analysis adopts the simulation of surface current and electrical field of heat sink. The disadvantage of traditional EMI filter, electric influence caused by PWM motor drive, was discovered. The improved design was done to restrain common-mode voltage and common-mode current. From the perspective of the EMC and low stray inductance bus bar, the terrace generatrix was developed to weaken the EMI.In the forth part, based on above achievements, an explosion-proof VFD integration induction motor used in scraper conveyor was developed. The experiment method of motors of this type was improved, and the experimental platform was constructed. Those all provided integrated design specification for the development of the explosion-proof VFD integration induction motor.