Position Sensorless Control for DSEG with Bridge Semi-controlled Rectifier Based on Current Gradient

The controlled rectification power generation technology can effectively improve the output power density of the doubly salient electro-magnetic generator (DSEG). This paper proposes a novel position sensorless control method for sinusoidal DSEG with bridge semi-controlled rectifier (BSR) based on current gradient. By analyzing the operating mode of the sinusoidal DSEG with BSR, the corresponding relationship between phase inductive electromotive force (EMF) and current gradient is explored within the typical negative commutation region. On this base, to solve the problem of the difficult calculation for current gradient caused by PWM chopping in actual sinusoidal DSEG system, a current gradient acquisition method based on pulse triggering is put forward to identify three-phase back EMF information. Furthermore, a triggering information constraint method based on non-conductive phase judgment is established to avoid the possible error trigging caused by the reverse freewheeling. Finally, the estimated rotor position through the whole electrical cycle is obtained according to the three basic reference angular positions as well as the estimated angular velocity. No extra hardware is required for the proposed methods, and the multiple experiments validate the correctness and flexibility of the proposed methods.