The Experts below are selected from a list of 40536 Experts worldwide ranked by ideXlab platform
Kyo-beum Lee - One of the best experts on this subject based on the ideXlab platform.
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Sinusoidal Harmonic Voltage Injection PWM Method for Vienna Rectifier With an LCL Filter
IEEE Transactions on Power Electronics, 2021Co-Authors: Jin-hyuk Park, June-seok Lee, Kyo-beum LeeAbstract:This article proposes a Harmonic Voltage injection pulsewidth modulation (PWM) method for a Vienna rectifier with an LCL filter. Existing PWM methods for Vienna rectifiers with full power factor can lead to resonance problems. It generates current oscillation at the resonant frequency. It is analyzed that why the resonance problem occurs in Vienna rectifier with the existing PWM methods. To solve these resonance problems, the proposed method injects a sinusoidal Harmonic Voltage into the sinusoidal reference Voltage. The magnitude and phase of the injection Voltage are determined by the power factor of the rectifier-side. Compared to other PWM methods, the proposed PWM method eliminates the possibility of resonant problems. Considering the operation characteristics of the proposed PWM method, this article suggests a design process for an LCL filter. The effectiveness and performance of the proposed PWM method and the design process for an LCL filter are verified by simulation and experiment.
Y. Nakagawa - One of the best experts on this subject based on the ideXlab platform.
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Inductive measurements of third-Harmonic Voltage and critical current density in bulk superconductors
Applied Physics Letters, 2003Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:We propose an inductive method to measure critical current density $J_c$ in bulk superconductors. In this method, an ac magnetic field is generated by a drive current $I_0$ flowing in a small coil mounted just above the flat surface of superconductors, and the third-Harmonic Voltage $V_3$ induced in the coil is detected. We present theoretical calculation based on the critical state model for the ac response of bulk superconductors, and we show that the third-Harmonic Voltage detected in the inductive measurements is expressed as $V_3= G_3\omega I_0^2/J_c$, where $\omega/2\pi$ is the frequency of the drive current, and $G_3$ is a factor determined by the configuration of the coil. We measured the $I_0$-$V_3$ curves of a melt-textured $\rm YBa_2Cu_3O_{7-\delta}$ bulk sample, and evaluated the $J_c$ by using the theoretical results.
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inductive measurements of third Harmonic Voltage and critical current density in bulk superconductors
Applied Physics Letters, 2003Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:We propose an inductive method to measure critical current density Jc in bulk superconductors. In this method, an ac magnetic field is generated by a drive current I0 flowing in a small coil mounted just above the flat surface of superconductors, and the third-Harmonic Voltage V3 induced in the coil is detected. We present theoretical calculation based on the critical state model for the ac response of bulk superconductors, and we show that the third-Harmonic Voltage detected in the inductive measurements is expressed as V3=G3ωI02/Jc, where ω/2π is the frequency of the drive current, and G3 is a factor determined by the configuration of the coil. We measured the I0–V3 curves of a melt-textured YBa2Cu3O7−δ bulk sample, and evaluated the Jc by using the theoretical results.
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Numerical calculation of critical current density and third Harmonic Voltage in superconducting films
Physica C-superconductivity and Its Applications, 2003Co-Authors: H Wada, Y. Mawatari, H. Yamasaki, Edmund Soji Otabe, Masaru Kiuchi, Teruo Matsushita, M Migita, Y. NakagawaAbstract:Abstract When an AC magnetic field of a suitable magnitude is applied locally to a wide surface of a superconducting film, a third Harmonic Voltage is induced in a pick-up coil. This measurement is used for an evaluation of the critical current density of the film. Mawatari et al. analyzed the relationship between the third Harmonic Voltage amplitude (V3) and the driving current amplitude for the field (I0) by using the critical state model and a simple assumption that the magnetic field is locally parallel to a flat surface. In this study, this relationship is numerically analyzed by finite element method (FEM) for a condition similar to the experiment by Mawatari et al. This result is compared with the above theoretical and experimental results. Some deviations from theory are found. However, the scaling of V3–I0 curves holds and I0 at which V3 starts to appear is proportional to the critical current density.
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Theoretical investigation on 3rd Harmonic Voltage in inductive measurements of critical current density in superconducting films
IEEE Transactions on Appiled Superconductivity, 2003Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:We have theoretically investigated third-Harmonic Voltage detected in a widely-used inductive measurement of critical current density J/sub c/ in superconducting films. In the inductive measurement, an ac drive current I/sub 0/ cos /spl omega/t flows in a small coil close to the surface of a superconducting film, and third-Harmonic Voltage V/sub 3/ cos(3/spl omega/t + /spl theta//sub 3/) induced in the coil is detected. The relationships among the ac drive current I/sub 0/, the amplitude V/sub 3/, and the phase /spl theta//sub 3/ of the third-Harmonic Voltage are derived on the bases of the critical state model. When the drive current is smaller than a threshold value I/sub c0/, the third-Harmonic Voltage is near zero, V/sub 3/ /spl ap/ 0 for I/sub 0/ I/sub c0/, on the other hand, the third-Harmonic Voltage is expressed as V/sub 3/ exp(-i/spl theta//sub 3/) = /spl omega/I/sub c0/ G/sub 3/(I/sub 0//I/sub c0/), where G/sub 3/(/spl gamma/) is a scaling function determined by the configuration of the coil. The predicted scaling law of V/sub 3//I/sub c0/ and /spl theta//sub 3/ as functions of I/sub 0//I/sub c0/ is clearly observed in an YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// film.
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critical current density and third Harmonic Voltage in superconducting films
Applied Physics Letters, 2002Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:When a sinusoidal drive current I0 cos ωt flows in a small coil close to the surface of a superconducting film, third-Harmonic Voltage V3 cos(3ωt+θ3) is induced in the coil if the film causes a nonlinear response. We have developed an approximate theoretical method yielding the relationships among I0, V3, and θ3, thus providing the scientific basis for a widely used inductive method for measuring the critical current density Jc in large-area superconducting films. Our results show that V3 is near zero when I0 is smaller than a threshold value Ic0∝Jcd, where d is the film thickness. When I0>Ic0, on the other hand, the third-Harmonic Voltage is expressed as V3 exp(−iθ3)=ωIc0G(I0/Ic0), where G(x) is a scaling function determined by the configuration of the coil. We demonstrate the scaling law of V3/Ic0 vs I0/Ic0 in a YBa2Cu3O7−δ film.
Jin-hyuk Park - One of the best experts on this subject based on the ideXlab platform.
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Sinusoidal Harmonic Voltage Injection PWM Method for Vienna Rectifier With an LCL Filter
IEEE Transactions on Power Electronics, 2021Co-Authors: Jin-hyuk Park, June-seok Lee, Kyo-beum LeeAbstract:This article proposes a Harmonic Voltage injection pulsewidth modulation (PWM) method for a Vienna rectifier with an LCL filter. Existing PWM methods for Vienna rectifiers with full power factor can lead to resonance problems. It generates current oscillation at the resonant frequency. It is analyzed that why the resonance problem occurs in Vienna rectifier with the existing PWM methods. To solve these resonance problems, the proposed method injects a sinusoidal Harmonic Voltage into the sinusoidal reference Voltage. The magnitude and phase of the injection Voltage are determined by the power factor of the rectifier-side. Compared to other PWM methods, the proposed PWM method eliminates the possibility of resonant problems. Considering the operation characteristics of the proposed PWM method, this article suggests a design process for an LCL filter. The effectiveness and performance of the proposed PWM method and the design process for an LCL filter are verified by simulation and experiment.
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Sinusoidal Third Harmonic Voltage Injection PWM Method for Applying the LCL Filter to Vienna Rectifiers
2019Co-Authors: Jin-hyuk Park, June-seok Lee, Ui-min ChoiAbstract:This paper proposes the sinusoidal third Harmonic Voltage injection pulse-width modulation method for applying the LCL filter to Vienna rectifiers. The LCL filter can lead to the resonant problem in the CL part of LCL filter. This problem generates the current oscillation at the resonant frequency; therefore, the system using LCL filter becomes unstable. To overcome this problem, the controller bandwidth, switching frequency, PWM method, and active damping method are considered in design process. However, the existing PWM methods for the full power factor operation generates the resonant current. The proposed method injects the sinusoidal third Harmonic Voltage to the sinusoidal reference Voltages. The magnitude and phase of the injection Voltage are determined depending on the modulation index, power factor, filter impedances, and grid magnitude. Compared to other PWM methods, the probability of the resonant problem due to the PWM method is eliminated by using the proposed method. The effectiveness and performance of the proposed sinusoidal third Harmonic Voltage injection method are verified by simulation.
Y. Mawatari - One of the best experts on this subject based on the ideXlab platform.
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Inductive measurements of third-Harmonic Voltage and critical current density in bulk superconductors
Applied Physics Letters, 2003Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:We propose an inductive method to measure critical current density $J_c$ in bulk superconductors. In this method, an ac magnetic field is generated by a drive current $I_0$ flowing in a small coil mounted just above the flat surface of superconductors, and the third-Harmonic Voltage $V_3$ induced in the coil is detected. We present theoretical calculation based on the critical state model for the ac response of bulk superconductors, and we show that the third-Harmonic Voltage detected in the inductive measurements is expressed as $V_3= G_3\omega I_0^2/J_c$, where $\omega/2\pi$ is the frequency of the drive current, and $G_3$ is a factor determined by the configuration of the coil. We measured the $I_0$-$V_3$ curves of a melt-textured $\rm YBa_2Cu_3O_{7-\delta}$ bulk sample, and evaluated the $J_c$ by using the theoretical results.
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inductive measurements of third Harmonic Voltage and critical current density in bulk superconductors
Applied Physics Letters, 2003Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:We propose an inductive method to measure critical current density Jc in bulk superconductors. In this method, an ac magnetic field is generated by a drive current I0 flowing in a small coil mounted just above the flat surface of superconductors, and the third-Harmonic Voltage V3 induced in the coil is detected. We present theoretical calculation based on the critical state model for the ac response of bulk superconductors, and we show that the third-Harmonic Voltage detected in the inductive measurements is expressed as V3=G3ωI02/Jc, where ω/2π is the frequency of the drive current, and G3 is a factor determined by the configuration of the coil. We measured the I0–V3 curves of a melt-textured YBa2Cu3O7−δ bulk sample, and evaluated the Jc by using the theoretical results.
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Numerical calculation of critical current density and third Harmonic Voltage in superconducting films
Physica C-superconductivity and Its Applications, 2003Co-Authors: H Wada, Y. Mawatari, H. Yamasaki, Edmund Soji Otabe, Masaru Kiuchi, Teruo Matsushita, M Migita, Y. NakagawaAbstract:Abstract When an AC magnetic field of a suitable magnitude is applied locally to a wide surface of a superconducting film, a third Harmonic Voltage is induced in a pick-up coil. This measurement is used for an evaluation of the critical current density of the film. Mawatari et al. analyzed the relationship between the third Harmonic Voltage amplitude (V3) and the driving current amplitude for the field (I0) by using the critical state model and a simple assumption that the magnetic field is locally parallel to a flat surface. In this study, this relationship is numerically analyzed by finite element method (FEM) for a condition similar to the experiment by Mawatari et al. This result is compared with the above theoretical and experimental results. Some deviations from theory are found. However, the scaling of V3–I0 curves holds and I0 at which V3 starts to appear is proportional to the critical current density.
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Theoretical investigation on 3rd Harmonic Voltage in inductive measurements of critical current density in superconducting films
IEEE Transactions on Appiled Superconductivity, 2003Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:We have theoretically investigated third-Harmonic Voltage detected in a widely-used inductive measurement of critical current density J/sub c/ in superconducting films. In the inductive measurement, an ac drive current I/sub 0/ cos /spl omega/t flows in a small coil close to the surface of a superconducting film, and third-Harmonic Voltage V/sub 3/ cos(3/spl omega/t + /spl theta//sub 3/) induced in the coil is detected. The relationships among the ac drive current I/sub 0/, the amplitude V/sub 3/, and the phase /spl theta//sub 3/ of the third-Harmonic Voltage are derived on the bases of the critical state model. When the drive current is smaller than a threshold value I/sub c0/, the third-Harmonic Voltage is near zero, V/sub 3/ /spl ap/ 0 for I/sub 0/ I/sub c0/, on the other hand, the third-Harmonic Voltage is expressed as V/sub 3/ exp(-i/spl theta//sub 3/) = /spl omega/I/sub c0/ G/sub 3/(I/sub 0//I/sub c0/), where G/sub 3/(/spl gamma/) is a scaling function determined by the configuration of the coil. The predicted scaling law of V/sub 3//I/sub c0/ and /spl theta//sub 3/ as functions of I/sub 0//I/sub c0/ is clearly observed in an YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// film.
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critical current density and third Harmonic Voltage in superconducting films
Applied Physics Letters, 2002Co-Authors: Y. Mawatari, H. Yamasaki, Y. NakagawaAbstract:When a sinusoidal drive current I0 cos ωt flows in a small coil close to the surface of a superconducting film, third-Harmonic Voltage V3 cos(3ωt+θ3) is induced in the coil if the film causes a nonlinear response. We have developed an approximate theoretical method yielding the relationships among I0, V3, and θ3, thus providing the scientific basis for a widely used inductive method for measuring the critical current density Jc in large-area superconducting films. Our results show that V3 is near zero when I0 is smaller than a threshold value Ic0∝Jcd, where d is the film thickness. When I0>Ic0, on the other hand, the third-Harmonic Voltage is expressed as V3 exp(−iθ3)=ωIc0G(I0/Ic0), where G(x) is a scaling function determined by the configuration of the coil. We demonstrate the scaling law of V3/Ic0 vs I0/Ic0 in a YBa2Cu3O7−δ film.
June-seok Lee - One of the best experts on this subject based on the ideXlab platform.
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Sinusoidal Harmonic Voltage Injection PWM Method for Vienna Rectifier With an LCL Filter
IEEE Transactions on Power Electronics, 2021Co-Authors: Jin-hyuk Park, June-seok Lee, Kyo-beum LeeAbstract:This article proposes a Harmonic Voltage injection pulsewidth modulation (PWM) method for a Vienna rectifier with an LCL filter. Existing PWM methods for Vienna rectifiers with full power factor can lead to resonance problems. It generates current oscillation at the resonant frequency. It is analyzed that why the resonance problem occurs in Vienna rectifier with the existing PWM methods. To solve these resonance problems, the proposed method injects a sinusoidal Harmonic Voltage into the sinusoidal reference Voltage. The magnitude and phase of the injection Voltage are determined by the power factor of the rectifier-side. Compared to other PWM methods, the proposed PWM method eliminates the possibility of resonant problems. Considering the operation characteristics of the proposed PWM method, this article suggests a design process for an LCL filter. The effectiveness and performance of the proposed PWM method and the design process for an LCL filter are verified by simulation and experiment.
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Sinusoidal Third Harmonic Voltage Injection PWM Method for Applying the LCL Filter to Vienna Rectifiers
2019Co-Authors: Jin-hyuk Park, June-seok Lee, Ui-min ChoiAbstract:This paper proposes the sinusoidal third Harmonic Voltage injection pulse-width modulation method for applying the LCL filter to Vienna rectifiers. The LCL filter can lead to the resonant problem in the CL part of LCL filter. This problem generates the current oscillation at the resonant frequency; therefore, the system using LCL filter becomes unstable. To overcome this problem, the controller bandwidth, switching frequency, PWM method, and active damping method are considered in design process. However, the existing PWM methods for the full power factor operation generates the resonant current. The proposed method injects the sinusoidal third Harmonic Voltage to the sinusoidal reference Voltages. The magnitude and phase of the injection Voltage are determined depending on the modulation index, power factor, filter impedances, and grid magnitude. Compared to other PWM methods, the probability of the resonant problem due to the PWM method is eliminated by using the proposed method. The effectiveness and performance of the proposed sinusoidal third Harmonic Voltage injection method are verified by simulation.
