Sensorless PM brushless DC motor drives

Sensorless Control of PMSM by a Four-Switch Inverter with Compensation of Voltage Distortion and Adjustment of Position Estimation Gain

“…In order to help understanding the gain adjustment scheme, speed and position estimation algorithm and stability of the current model-based sensorless control proposed by Matsui [2,13] are explained in this section.…”

“…The schemes in [3,16] are for twophase conduction method, and the method presented in [17] by a Kalman filter is relatively complex. Hence, this paper presents a simple sensorless scheme implemented with a B4 inverter, which is based on the back-EMF detection method reported in Matsui's papers [2,13]. Where, in the sensorless schemes of [2,13] for home appliances application, B6 inverters are involved for power conversion.…”

“…Sensors and power switches are relatively expensive, so that cost-effective driving schemes have been widely researched [1][2][3]. In order to reduce total number of power switches, the B4 topology that uses only 4 switches instead of six switches (B6 topology) was introduced [1].…”

“…On the other hand, the back-EMF based sensorless method [2,13] estimates the rotor position by using stator voltages and currents. The back-EMF based scheme cannot get reliable rotor position in the low-speed region because of relatively small back-EMF in that region.…”

“…To drive PMSM with cost-effective way, this paper applies B4 topology as well as sensorless scheme to PMSM controller. Sensorless control methods [2,10] are researched widely to have cost reduction, to cope with the application under the environment having the difficulty of using sensors, and/or to provide an alternative for the emergency operation against sensor failures. Sensorless schemes can be classified into two categories as the signal injection method and the back-EMF detection method.…”