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RISS 인기검색어
- 검색키워드
- 저자 : Zhou Shuihua (검색결과 4 건)
- 무료
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Multiple reference frame-based current harmonic control for interior PMSMs considering motional EMF
Zhong, Zaimin,Zhou, Shuihua,Shao, Zhongshu The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.6
For permanent magnet synchronous machines (PMSMs), current harmonics need to be controlled under two kinds of conditions. Under the first condition, the current harmonics caused by the non-sinusoidal back-electromotive force (EMF) and the dead time of inverters should be suppressed. Under the second condition, specific current harmonics should be injected to suppress the torque ripple of motors. Therefore, the accurate control of current harmonics is critical. It has been found that the original multiple reference frame (MRF)-based control algorithm cannot effectively achieve the control of current harmonics at high speeds. For the currents in MRFs, motional EMF was dominant rather than induced EMF at higher speeds. As a result, the original MRF-based control algorithm does not work at high speeds. To solve this problem, this paper proposed a novel MRF-based control algorithm that considers motional EMF. Furthermore, this paper achieved decoupling control of the current harmonics in MRFs for interior PMSMs. With the proposed control algorithm, the current harmonics of interior PMSMs can be controlled at both high and low speeds. Under the influence of non-sinusoidal back EMF and the dead time of the inverter, the effect of current harmonic control was verified on a laboratory test bench.
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Current harmonic selection for torque ripple suppression based on analytical torque model of PMSMs
Zhong, Zaimin,Zhou, Shuihua,Hu, Chengyu,You, Junming The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4
For permanent magnet synchronous motors (PMSMs) without sufficient design optimization, it is necessary to inject current harmonics to suppress torque ripple. Due to the influence of magnetic saturation, the current harmonics for torque ripple suppression changes with the electrical loads. Based on an existing analytical torque model of a PMSM considering spatial harmonics and magnetic saturation, this paper established a torque harmonic coupling model through a Taylor expansion and a harmonic balance method. Then, based on the torque harmonic coupling model, current harmonic selection for torque ripple minimization was proposed. The validity of the torque harmonic coupling model and current harmonic selection was verified by a finite element analysis (FEA) and experiments on a laboratory PMSM drive system.
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Zhong, Zaimin,Shao, Zhongshu,Zhou, Shuihua The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.10
Pulsating high-frequency voltage injection is an effective method for estimating the initial rotor position for interior permanent magnet synchronous motors (IPMSMs). This method is based on the magnetic saliency of a motor rather than a back-electromotive-force (back-EMF) model. In addition, it is feasible when the motor is static or in low-speed operations. However, accurate estimation of the rotor position is realized on the assumption that the direct-axis and quadrature-axis of the motor are completely decoupled, which is not always satisfied. Then, the mutual inductance between the two axes introduces a theoretical error into the rotor position estimation. In this paper, the theoretical error of the rotor position estimation caused by mutual inductance is deduced. An improved initial rotor position estimation method is proposed to eliminate harmonic theoretical errors by injecting high-frequency voltage in the decoupling coordinate system. Finally, the effectiveness of this method is verified by experimental results.
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Probability Evaluation of Hydrodynamic Shear Damage for Fish Passing through Jet Fish Pumps
Maosen Xu,Jiegang Mou,Denghao Wu,Peijian Zhou,Yunqing Gu,Shuihua Zheng 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2
Jet fish pump is an efficient tool to transport fish. Due to the operation principle, shear flow cannot be avoided in jet fish pumps. Shear flow is a potential risk for fish damage in the fluid machinery. Therefore, it is valuable to evaluate the probability of hydrodynamic shear damage for fish passing through jet fish pumps. In the present study, the numerical investigation was performed on the distribution of dangerous region, where exposure strain rate was above 500 s-1, and probability of hydrodynamic shear damage for fish. Experiments were conducted to check the damage probability calculated by numerical simulation and the injury of fish was analyzed. The results showed that the dangerous region is usually distributed in the near wall region. As the rise of flow ratio, the range of dangerous region gradually became wider and the dangerous region extended into the throat. In the same inlet boundary conditions, the damage probability is lower for a jet fish pump with a bigger area ratio. With the increase of flow ratio, both probability of hydrodynamic shear damage and effect of area ratio grow. Compared with the results of experiments, the probability of hydrodynamic shear damage can be overestimated. The main reasons lie in the extremely short transit time for fish, independent movement of fish and the velocity difference between fish and flow.
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