Research on sensorless and advanced angle control strategies for doubly salient electro‐magnetic motor

A starter generator is a core technology of the more-electric aircraft and all-electric aircraft. The traditional switched reluctance machine (SRM) requires a high accuracy position sensor and high-speed processor while generating power. Therefore, the cost of the controller is high and the maximum speed of the machine is limited. A dual-mode doubly salient starter/generator is proposed in the study. In the process of starting and generating power, the machine operates based on the SRM principle and the doubly salient electromagnetic machine principle, respectively. In order to realise the transformation of the operating principle, the machine uses a winding switching device, and half of the windings are replaced as field winding that provide DC excitation in the generator mode. A suitable power converter is proposed based on introducing the structure and working principle of the machine. A winding switching device is designed, and the conversion process is explained in detail. A finite-element method is simultaneously used to analyse the motor-driven performance and the power-generation performance of the machine. A 12/8-pole prototype machine is developed. Additionally, the effectiveness of the starting, generating, and dualmode conversion is verified by experiments.

Section: Starting Characteristics Of Dmdss/gmentioning

confidence: 99%

Investigation of the working mechanism and characteristics of dual‐mode doubly salient starter generator with variable winding

Xiao

Shi

Guo

et al. 2018

“…The proposed sensorless control strategy based on line-voltage is inapplicable at standstill or very low speeds due to the small magnitude of back EMFs. In this paper, the sensorless start-up method 'align and go' is applied [5,18]. Fig.…”

Section: Start-up Techniquementioning

confidence: 99%

Position sensorless control for doubly salient electro‐magnetic motor based on line‐to‐line voltage

Zhou

Zhang

Liu

2017

Self Cite

This study first proposes a novel position sensorless control method for doubly salient electromagnetic motor (DSEM) based on line-to-line voltage. The commutation instants are estimated by comparing the proper line-to-line voltage with a commutation threshold value, which is preset according to motor speed and field current. Since only line-voltage is required, the negative influence of DSEM neutral point voltage variation is eliminated. Moreover in addition, line-to-line voltage has a gain of phase back-electromotive force (EMF), so the application speed range is desired to be extended. Then, the sensorless commutation lags introduced by reluctance back EMFs and low-pass filters are analysed in detail, with the obtained mathematic expressions, a uniform compensation strategy by adjusting the commutation threshold value is proposed. With no need for extra hardware, the compensation strategy has the merit of easy implementation. What is more, to overcome the restriction of the distorted commutation signal arising in freewheeling process, a constraint of three-phase currents is developed to avoid false commutation. Finally, the experiments on a 12/8-pole DSEM validate the correctness and feasibility of the proposed techniques.

“…However, this method does not take the effect of armature reaction into account and it is not applicable under loaded condition. Based on the characteristics of the back EMF, the back EMF of non-conducting phase is directly detected and compared with a threshold value to obtain the commutation points in [17]. However, the neutral point needs to be extracted to obtain the phase voltage.…”

Section: Introductionmentioning

confidence: 99%

“…The commutation error introduced by reluctance back EMFs and LPFs are analysed and compensated. However, the threshold value in the two methods mentioned in [17,18] is affected by many factors, such as the speed, the excitation current and the structure parameter, which brings low universality.…”

Section: Introductionmentioning

confidence: 99%

“…The methods in [12,18] are not applicable to the TSSAC due to the change in the waveforms of the terminal voltage and line-to-line voltage. The method in [17] needs to rebuild the relationship between the threshold values of the back EMF of nonconducting phase and the advanced commutation points. However, this method has the same disadvantage of the need for the neutral point.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sensorless control strategy for doubly salient electro‐magnetic machine based on the line‐to‐line excitation flux linkage

Liu

Wang

et al. 2019

This article presents a sensorless control strategy based on the line-to-line excitation flux linkage for doubly salient electromagnetic machine. The negative-going zero-crossing points of the line-to-line excitation flux linkage are detected to estimate the position and speed. To solve the problems of direct current (DC) bias and error accumulation in pure integrator, a combination of first-order low-pass filter and first-order high-pass filter is adopted to estimate the line-to-line flux linkage. Considering that the self-inductance obviously varies with the position and the phase current, an equivalent inductance is introduced to calculate the line-to-line excitation flux linkage in the whole period. The commutation error caused by the filter and the armature reaction is analysed and proved to be within ±6°. The proposed method can be applied to either the three-state standard angle control or the six-state advanced angle control. The experiment platform based on a 9-kW/3000-rpm DSEM is built, and the validity and feasibility of the proposed strategy are proved.