Self-Learning Direct Flux Vector Control of Interior Permanent-Magnet Machine Drives

Abstract

This paper proposes a novel self-learning control scheme for interior permanent magnet synchronous machine (IPMSM) drives to achieve maximum torque per ampere (MTPA) operation in constant torque region and voltage constraint maximum torque per ampere (VCMTPA) operation in field weakening region. The proposed self-learning control scheme (SLC) is based on the newly reported virtual signal injection aided direct flux vector control. However, other searching based optimal control schemes in the flux-torque (f-t) reference frame are also possible. Initially the reference flux amplitudes for MTPA operations are tracked by virtual signal injection and the data are used by the proposed self-learning control scheme to train the reference flux map online. After training, the proposed control scheme generates the optimal reference flux amplitude with fast dynamic response. The proposed control scheme can achieve MTPA or VCMTPA control fast and accurately without accurate prior knowledge of machine parameters and can adapt to machine parameter changes during operation. The proposed control scheme is verified by experiments under various operation conditions on a prototype 10 kW IPMSM drive. Index Terms-Maximum torque per Ampere (MTPA) operation, Permanent magnet synchronous machine (IPMSM), Self-learning control, Signal injection. Tianfu Sun (S'15) was born in China. He received B.Eng. degree in mechanical engineering, M.Sc. degree in civil engineering

Novel MTPA control strategy for IPMSM based on multiple virtual signals injection

“…The conventional method eliminates the cos( h t) term with the help of the LPF despite of its phase delay. If the two opposite small high-frequency signals about cos( h t) expressed as (17) are virtually injected into the current angle, respectively, the instantaneous input power P ivir2 and P ivir3 can be calculated as (18) and (19) similarly…”

“…Although the MTPA methods based on signals injection are independent of machine parameters, they would entail the torque ripples and the additional power losses owing to the injection of signals. In order to eliminate these problems in the utilisation of real signal injection, the virtual signal injection methods emerge to enhance efficiency in [16][17][18][19]. When a small high-frequency signal is injected into the measured stator current angle mathematically, there exists high-frequency disturbance in the corresponding calculated instantaneous power.…”

MTPA Control of IPMSM Drives Based on Virtual Signal Injection Considering Machine Parameter Variations

“…(6) (7) However, it is highly important to note that even though the machine parameters employed in (6) and (7) are accurate, precise MTPA operation still cannot be achieved. This is due to the neglect of the derivative terms ( , , ) in (5). The influence of these derivatives in (5), namely, , , increases with load or current amplitude .…”

“…temperature [5]. Therefore, to achieve the accurate MTPA operation is one of the significant challenges associated with the IPMSM control techniques and a large number of studies have been reported in the literature to improve the efficiency of the IPMSM drives.…”

Performance improvement of direct torque controlled permanent magnet synchronous motor drives

“…Plenty of research papers have been published to investigate the FW operations of direct torque controlled electric machines [73][74][75][76][77][78][79]. Unfortunately, many of them focus on the field-weakening operation of direct torque controlled induction motors and thus are not readily applicable to the PMSMs [73,77,79].…”