A Novel Synchronous Switch Method Based on Kalman Filter

In order to create the idea of AC switch without electric arc and inrush voltage to the power system, the study of accurately catches AC zero crossing of a mechanical relay is put forward in this paper. It is the key to make the switch act at the right predicted time which realizes switch on or off exactly at the AC zero crossing point. However, the action time of a mechanical switch is affect by many factors such as driving voltage, ambient temperature, age of the mechanic structure. Aim at the discrete measurements of latching relay action time, the Kalman filter mathematic model is introduced in this paper to eliminate the dynamic noise and measurement noise which affects the bias time drift from the zero voltage or zero current point. Simulation result by matlab and group data get from experiments of a realized multichannel switch indicate that Kalman filter algorithm can overcome the discreteness of latching relay action time measurements. Also confirmed by statistical experiments that synchronous switch action precisely and reliably at AC zero point which can ensure the ability of suppress electric arc and high frequency inrush current.