Research On Pure Electric Brake Strategy For Linear Induction Motor Drives

With the rapid growth of Linear Metro systems, LIM (Linear Induction Motor) is more and more applied all over the world. LIM drive has many advantages, but now most linear motor metros around the world use air and electric blended brake, shortcomings of which are switch between air and electric brake may lead to large Jerk, bring about bad ride comfort and inaccurate train locating stop. Pure electric brake without switch between air and electric brake is gradually used in rotary induction motor driven vehicles, while is not discussed in linear induction motor drives so far, not to mention experiments and applications. Referring to rotary induction motor control method, this paper concentrates on pure electric brake in LIM, and discusses the implementation viability in Guangzhou Subway Line 4.In this paper, a dynamic mathematical model of LIM considering end-effect is derived based on the eddy current loss. Then a field orientation control scheme is developed through the analysis of the difference of linear motor and rotary motor control. Giving speed instruction in traction condition and giving force instruction in brake condition to achieve pure electric brake in LIM, which is composed of regenerative brake and reverse brake. Jerk control is introduced at the final stage according to ride comfort requirements. This paper also discusses the switching mode from regenerative brake to reversal brake, and removal time of reversal brake.In order to authenticate the pure electric brake strategy, the simulation system is built based on Matlab/Simulink software. The simulative results validate the effectiveness of pure electric brake strategy. And set up the LIM drive system modeled the urban rail transit lines. The experimental results show that control methods realize pure electric brake in LIM and designed stop within the specified distance.