Open AccessImproved position signal demodulation method for sensorless control based on HF sinusoidal pulsating voltage injection
Author(s) -
Liu Jiali,
Zhang Yongchang,
Yang Haitao
Publication year - 2020
Publication title -
iet electric power applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.815
H-Index - 97
eISSN - 1751-8679
pISSN - 1751-8660
DOI - 10.1049/iet-epa.2020.0500
Subject(s) - control theory (sociology) , demodulation , harmonics , phase locked loop , low pass filter , bandwidth (computing) , voltage , settling time , signal (programming language) , position (finance) , step response , physics , computer science , phase (matter) , engineering , telecommunications , electrical engineering , channel (broadcasting) , control (management) , quantum mechanics , artificial intelligence , control engineering , finance , economics , programming language
High frequency (HF) sinusoidal pulsating voltage injection is a reliable method for position sensorless control in low speed range. For HF voltage injection based methods, position signal demodulation plays a key role. However, the conventional sinusoidal demodulation suffers from long settling time and limited bandwidth because of requirement of a low‐pass filter (LPF) to suppress HF harmonics in the estimated position. Additionally, the overall performance is deteriorated due to the characteristic of linear demodulation. To address these issues, the cube of q ‐axis HF current instead of itself is used as the carrier of position estimation error. In this way, the input variable for phase‐locked loop (PLL) is the cube function with respect to the position deviation. During steady state, the equivalent gain in PLL is very small and thus the estimated position is non‐sensitive against high‐frequency harmonics, thereby the LPF is no longer required in the proposed method. While during dynamic process, the equivalent gain is increased leading to a fast converging rate when compared with the conventional method. The stability and dynamic performance are theoretically analysed by the magnitude–frequency diagram. The superiority of the proposed method was experimentally justified and the obtained results show that both steady‐state and dynamic performance are improved when compared with the prior art.