Research On Star Sealing Protection Technology Of Permanent Magnet Synchronous Elevator Drive

China is a big country in the production and use of elevators,ranking No.1 in the number of elevators,annual output and annual increment.By the end of 2018,elevators in use have reached 6.2 million units,and the production and new increment of elevators are 780,000 units and 680,000 units respectively,accounting for about 75% and 65% respectively in the world.Elevators have become an indispensable public transport in the cities.“The first step of leaving home and last step of coming back home.” According to conservative estimates,there are 1.5 billion people taking elevators every day all over the country.Elevators have become an essential vertical vehicle for the daily life of the people,and have drawn more and more attention of the society.The braking ability of the elevator traction machine is the key factor to ensure the safety of the elevator.This paper aims to study the short-circuit technology of the most widely used permanent magnet synchronous gearless traction machine,and provide references for elevator safety configuration.Firstly,this paper introduces the research status of the short-circuit technology of permanent magnet synchronous gearless traction machine both in China and abroad,then it gives a brief introduction of the braking system requirements in standards for the traction machine.It analyzes the failure conditions of current traction machine braking system,leading out the concept of the short-circuit braking technology of the permanent magnet synchronous gearless traction machine.According to the basic model of the short-circuit braking,this paper conducts formula deducing of the short-circuit braking,and gives the formula for calculating the slipping speed of short-circuit braking in the condition of stationary or low speed of the elevator,as well as the formula for calculating the current and reverse torque of short-circuit braking in case of traction machine's high speed travelling.Meanwhile,this paper introduces the static characteristic theory of short-circuit braking of permanent magnet synchronous traction machine,and adopts two test methods to verify this theory,thus determining the applicable scope of this calculation formula.According to the static characteristics theory of short-circuit braking of permanent magnet synchronous traction machine,this paper proposes an delay type short-circuit solution,by using delay function based on the traditional short-circuit scheme.For the conventional and delay type short-circuit scheme,firstly,the protection function of the short-circuit braking to the static elevator is verified,and then the differences in practical application between them are verified,providing demonstrations that the short-circuit braking has auxiliary protection functions to the permanent magnet synchronous gearless traction machine.