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

Abstract

-This paper proposes performance improvement schemes for sensorless PMSM control drive using a four-switch three-phase inverter (so-called B4 inverter). In the proposed scheme, the back-EMF estimation-based sensorless control algorithm is used to control the brushless PMSM without position sensors. In order to have stable operation, this paper presents a gain adjustment scheme that compensates the reduction of stable sensorless operation range as long as the rotor speed increases. In B4 topology, the center point of dc-link capacitors is connected to 3-phase load, and it is prone to have the load current distortion. Hence, to mitigate this problem, a distortion compensation scheme by modifying voltage commands using measured dc-link potentials is proposed in this paper. The validity of the proposed method is evaluated by simulations and experiments.

A Reference Voltage Self-Correction Method for Capacitor Voltage Offset Suppression of Three-Phase Four-Switch Inverter-Fed PMSM Drives

“…To reduce the computational effort of TPFS inverter-fed PMSM drive systems and to reduce the current ripple, the capacitor voltage offset suppression methods based on vector control are proposed in [12][13][14][15]. The capacitor voltage offset is eliminated by introducing a DC component compensation to the midpoint of the capacitor bank in [12], but the method introduces a second-order low-pass filter to extract the capacitor voltage deviation, which limits the dynamic and steady-state performance of the control system.…”

“…Although this method avoids the use of filters, the system adds a proportional-integral (PI) controller and requires the adjustment of parameters. In [15], the authors propose to directly measure the capacitor voltage using voltage sensors and then compensate the reference voltage using the difference between the capacitor voltage. This method requires no filter and no complex parameter adjustment and is easier to implement than the above methods.…”

Rotor Position Alignment of FSTPI Based PMSM Drive Using Low Frequency Signal Injection

“…Therefore, in this study, no details have been given on the encoder type or about the initial rotor position detection methodology. A study in the literature given in [15] discusses the initial rotor position alignment issue of the FSTP inverters. The solution to this problem explained in [8], which is locking the rotor with line-to-line voltage is possible but does not acquire zero angle alignment.…”