http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Liu Liu,Pan Luo,Junjie Zhao,Yuechen Rui 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.11
The rotating high-frequency (RHF) signal injection method is widely adopted for the initial position estimation in sensorless permanent magnet-assisted synchronous reluctance motor (PMa-SynRM) drives due to its simple implementation. However, the position estimation accuracy of the conventional method may be seriously deteriorated by the dead-zone effects of the inverter and the cross-saturation effects of the machine. Thus, to improve initial position estimation accuracy, a strategy to apply dual RHF signals is proposed in this paper. Different from the traditional solution, the proposed method sequentially injects dual RHF carrier voltages with the same frequencies but different amplitudes into the machine. Objective equations that consider the dead-zone and cross-coupling effects can be extracted from high-frequency response currents in turn. After the simple calculation, the initial position can be obtained directly and accurately, which effectively minimizes the influences of machine cross-saturation and inverter nonlinearities. The influence of the system delay on the rotor position estimation is also analyzed and deduced in detail. Finally, experimental results on a 5.5-kW PMa-SynRM indicate that the proposed method can achieve precise initial position estimation under any rotation position.
Van-Tinh Nguyen,Thanh-Tung Bui,Hai-Yen Pham 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.11
This paper expresses a novel adaptive fault-tolerant control (FTC) method for a robotic manipulator with dead zones and actuator faults in the task space. To specify, the actuator faults are the partial loss of effectiveness of actuators. The partial loss of effectiveness and the break-points of dead zone are estimated by the novel adaptive laws. Establishing an anti-singularity terminal sliding surface ensures the finite time convergence of the tracking errors to zero. The correctness of this method is proved by the Lyapunov criterion. Despite the fact that the proposed adaptive FTC method belongs to the passive group, it does not require any robust component which makes largemagnitude chattering phenomena to deal with the actuator faults. Instead, they are handled by a unique technique. The comparative simulation results illustrate the merit and efficiency of the proposed method.
71% Common‑mode voltage suppression modulation strategy for indirect matrix converters
Shanhu Li,Zijing Lu,Sunpeng Cao,Xu Liu,Zhaoyang Jin,Weitao Deng 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.2
Common-mode voltage (CMV) with a high amplitude and frequency is generated when an indirect matrix converter (IMC) is operating, which damages the motor winding insulation and accelerates motor aging. Existing IMC modulation methods can only suppress the CMV by 42.3%. However, this paper proposes a modulation strategy with a 71% reduction in the peak CMV. The proposed method selects active vectors based on the characteristics of the CMV amplitude under each of the active vectors. The rectifier stage selects two active vectors within each modulation sector. According to the sector where the input reference current vector is located, the inverter stage chooses active-voltage vectors whose corresponding peak CMV is 1/3 the minimum peak line voltage for modulation. Moreover, the CMV spikes caused by the dead zone effect are eliminated by reasonably arranging the switching sequence of the voltage vectors in the inverter stage. The proposed approach considerably lowers the peak CMV and has a good suppression effect on the amplitude of high-frequency CMV. Finally, experimental results illustrate the CMV reduction efficiency of the modulation strategy.