When system parameters falling into a certain area, the Synchronous Reluctance Motor drives (SynRM) will experience chaotic behavior, which threatens the secure and stable operation of drive system. To control the undesirable chaos or limit cycles in SynRM, a novel controller is proposed based on tridiagonal structure matrix stability theory. The proposed controller have some advantages: it is simple and easy to be implemented; the control transition time is very short and can be adjusted by change control parameters. Computer simulation results show that the presented controller is very effective. Our research results may help to maintain the SynRM drive system's secure operation.