Sinusoidal Injection Research Articles

Acoustic Noise Reduction for Low-Speed Sensorless Operation of Dual Three-Phase PMSM With Random Winding Injection

This paper proposes a pseudorandom sinusoidal voltage signal with random winding injection method to improve the acoustic noise reduction performance for the dual three-phase permanent magnet synchronous motor (DTP-PMSM). Compared to the conventional pseudorandom frequency sinusoidal injection method, the proposed method achieves better noise reduction with similar performance in position estimation. Two fixed frequency signals are randomly selected as injection signals. Then, one of the two sets of windings of the DTP-PMSM is randomly chosen for injection. Due to this unique injection scheme, the injected frequency component in the response current can be reduced. Two pseudorandom numbers are generated synchronously by the digital signal system. The first random number selects two voltage signals with different frequencies. Meanwhile, one of the two sets of windings is chosen by the second random number. Thus, there is only one winding with the injection signal at a certain time. In addition, the power spectral density of the response current caused by the injected signal is analyzed. Finally, the experimental results verify the proposed method.

Effect of sinusoidal injection velocity on miscible viscous fingering of a finite sample: Nonlinear simulation

The effect of a sinusoidal injection on the fingering instability in a miscible displacement in the application of liquid chromatography, pollutant contamination in aquifers, etc., is investigated. The injection velocity, U(t) is characterized by its amplitude of Γ and time-period of T. The solute transport, flow in porous media, and mass conservation in a two-dimensional porous media is modeled by the convection-diffusion equation, Darcy's equation, and the continuity equation, respectively. The numerical simulation is performed in COMSOL Multiphysics utilizing a finite-element based approach. The fingering dynamics for various time-period have been studied for two scenarios namely, injection-extraction (Γ>1) and extraction-injection (Γ<−1). The onset of fingers and vigorous mixing is observed for Γ>1, whereas for Γ<−1, the onset gets delayed. The viscosity contrast between the sample and the surrounding fluid is characterized by the log-mobility ratio R. When R>0 the rare interface becomes unstable, while for R<0 the frontal interface deformed. In the case of R<0, the extraction-injection process attenuates the fingering dynamics, which is beneficial in chromatographic separations or pollutant dispersion in underground aquifers. The injection-extraction process is observed to have a longer mixing length, indicating early interaction between both interfaces. The degree of mixing χ(t) is more pronounced for injection-extraction scenario and least for extraction-injection R<0,Γ=−2. The average convective forces are more dominant for Γ>1,R=2 till the deformed rare interface interact with diffusive frontal interface. The average diffusive forces are significant for Γ<−1,R=−2 which can be helpful in separation of chemicals in chromatography. This study therefore provided new insights into the role of alternate injection-extraction injections in altering the fingering dynamics of the miscible sample.

정현파 주입 방안 적용에 따른 HAPF용 패시브 필터 설계 방안의 역률 보상 정확성 개선

This paper proposes a method to compensate for the power factor error existing in the passive filter design method for HAPF by applying the sinusoidal wave injection method to the LC design method of the passive filter for HAPF. As the LC design method of the passive filter for HAPF assumes that is 1[p.u], it is necessary to completely compensate the harmonics included in the system to accurately compensate the power factor. This is a result of assuming an ideal case, and in practical terms, harmonics cannot be completely eliminated. Therefore, since is not 1[p.u], an error may occur in reactive power compensation. Accordingly, in this paper, we propose a method to reduce the power factor error by applying the sinusoidal injection method based on the default value used in the LC design method of the passive filter for HAPF for MI. The power factor error that appears when the sinusoidal wave injection method is applied to the LC design method of the passive filter for HAPF was precisely compared and analyzed, and the error and effect were analyzed through simulation. As a result, it was possible to see the result of reducing the error from 0.296 [%], which is the power factor error of the passive design method for HAPF, to about 0.04 [%] by applying the sinusoidal injection method.

Stabilization of periodically forced Hele-Shaw flows by means of a nonmonotonic viscosity profile.

The onset of viscous fingering in the presence of a viscosity profile is investigated theoretically for two immiscible fluids undergoing a time-dependent injection. Here, we show that the presence of a positive viscosity gradient at the interface between both fluids stabilizes the interface facilitating the spread of the perturbation. This effect is much more pronounced in the case of sinusoidal injection flows. The influence of the viscosity gradient on the dispersion relation is analyzed. Numerical simulations of the Navier-Stokes equationconfirm the linear stability analysis.

MTPA Control for IPMSM Drives Based on Pseudorandom Frequency-Switching Sinusoidal Signal Injection

Among various maximum torque per ampere (MTPA) control schemes for interior permanent magnet synchronous motor (IPMSM) drives, the signal-injection-based methods exhibit relatively high overall performance due to their high control accuracy and satisfactory dynamic performance. However, the high current spectrum peaks induced by the fixed-frequency signal injection may cause electromagnetic interference and even audible noise problems in applications, such as electric vehicles, vessels, and aircraft. To address this problem, an MTPA control method using pseudorandom frequency-switching sinusoidal signal injection is proposed in this paper. The sinusoidal signals with two different frequencies are randomly injected into the d- and q-axis currents and the MTPA points can be tracked according to the resultant system response. In this way, a high-performance MTPA control can be achieved regardless of motor parameter variations. Since the injection frequency of the proposed method varies randomly, the induced harmonic components in phase currents no longer concentrate at certain frequencies, and the current spectrum peaks caused by signal injection can be reduced accordingly. The experimental results demonstrate the validity of the presented method.

Computation of Phase Noise Spectrum in Optoelectronic Oscillator

A method for the phase noise characterization of single-loop optoelectronic oscillators (OEO) is presented. Based on the injection-pulling dynamics of OEO under radio frequency (RF) signal injection, this method is used to compute the phase noise spectrum of a free-running single-loop OEO. From the injection locking equation, the expression for the output RF spectrum of single-loop OEO under the influence of a single sinusoidal RF signal injection is derived and this analysis is then utilized to study the RF output power spectrum of the single-loop OEO when injected by two weak and equally strong RF sinusoidal signals with mirror frequencies with respect to the free-running frequency of the OEO. An expression for the far-out phase noise spectrum of a free-running single-loop OEO is presented to capture the far-out phase noise characteristics of the OEO. Also, we derive the expression for the close-in phase noise spectrum of the free-running single-loop OEO by considering the multiplicative noise as the overall loop-gain perturbation in the OEO loop. The experimental results are also given in partial support to the conclusions of the analysis.

Accuracy Improvement of Stator Inductance Identification Method Based on Low-Frequency Current Injection for Three-Level NPC Inverter-Fed IM Drives in Locked-Rotor Standstill Condition

In this paper, a stator inductance identification process is proposed. The process is based on a three-level neutral-point-clamped (NPC) inverter-fed induction motor (IM) drive with a standstill condition. Previously, a low-speed alternating current (AC) injection test for stator inductance identification was proposed to overcome practical problems in conventional identification methods for three-level NPC inverter-based IM drives. However, the low-speed AC injection test-based identification method has some problems if a heavy load or mechanical brake is connected, as these can forcibly bring the rotor to a standstill during parameter identification. Since this low-speed testing-based identification assumes the motor torque is considerably lower in low-speed operations, some inaccuracy is inevitable in this kind of standstill condition. In this paper, the proposed current injection speed generator is based on the previously studied low-speed test-based stator inductance identification method, but the proposed approach gives more accurate estimates under the aforementioned standstill conditions. The proposed method regulates the speed for sinusoidal low-frequency AC injection on the basis of the instantaneous reactive and air-gap active power ratio. This proposed stator inductance identification method is more accurate than conventional fixed low-frequency AC signal injection identification method for three-level NPC inverter-fed IM drive systems with a locked-rotor standstill condition. The proposed method’s accuracy and reliability were verified by simulation and experiment using an 18.5 kW induction motor.

NUMERICAL INVESTIGATION OF THE EFFECT OF PULSED INJECTION ON FILM COOLING EFFECTIVENESS OF TURBINE BLADE UNDER ROTATION

The effect of rotation on temperature distribution and film cooling effectiveness for turbine blade with sinusoidal and square pulsating coolant flow is numerically investigated. The RNG k−ε turbulent model is used to simulate the turbulence effects. Four rotation speeds of 0, 500, 800 and 1000 rpm are considered. Pulsed air coolant flow at three frequencies of 2, 50, and 500 Hz is injected to the turbine blade surface. It is to consider the combined effect of both rotation and pulsation parameters on film cooling performance simultaneously. The results show that pulsed film cooling effectiveness on pressure side and around the leading edge is reduced with increasing the rotational speed. On the suction side, with increasing rotational speed, film cooling effectiveness is decreased up to a distance of near the downstream of injection hole, but the behavior is reversed for further distances. In general, the pulsed film cooling effectiveness on the pressure side is greater than that on the suction side for different rotational speeds and frequencies. For sinusoidal and square pulsation, the deviation angle was almost the same but with increasing the rotational speed and pulsation frequency, the deflection increased. For various rotational speeds and frequencies, the film cooling effectiveness for sinusoidal injection flow is higher than for square wave flow.

Line Impedance Estimation

Line impedance estimation provides crucial information for power-line communication (PLC), power quality estimation, and grid-connected power electronics applications. Online techniques are particularly useful as the line impedance is time-dependent. This work uses a phase-controlled switch to generate a turn-on transient, which provides information about the line. Previous switching-based approaches focus on fitting line characteristics to a model. This article extends previous work by using a common electrical load in place of previously used capacitors, inductors, and short circuits. Nonparametric line impedance estimation is also demonstrated. An inrush transient generates a current with a wide-bandwidth spectral content to replace a sinusoidal injection sweep. Good estimation performance is demonstrated from dc up to 200 kHz.

Comparative Study on Performance Improvement of SPWM/THIPWM based DCMLI Grid Connected DFIG

Multi-level voltage source converter is integrated in various fields in renewable energy power generation technologies such as wind and solar sources for applications that need higher voltage and higher power. In wind power generation market, doubly fed induction generator (DFIG) based on wind power generation is now the leading technology as they are economically feasible, they do offer a variable speed and efficient substitute to the fossil fuel. This paper proposes a DFIG based on a back to back diode clamped multilevel converter systems (DCMLI) fired comparatively by sinusoidal pulse width modulation (SPWM) and third harmonic injection pulse width modulation (THIPWM) techniques. By using these technologies, the DFIG performance is compared for different wind speeds under normal operation condition. The proposed approach shows that the DCMLI systems generate a near sinusoidal voltage with lower values in total harmonic distortion (THD) thus, upgrading the power quality that is produced by DFIG. Lastly, the variation of frequency of induced rotor voltage and the active power flow due to the wind speed changes when the rotor speed changes from super synchronous to sub synchronous speeds is investigated.

Pseudorandom-Frequency Sinusoidal Injection for Position Sensorless IPMSM Drives Considering Sample and Hold Effect

The acoustic noises caused by the fixed-frequency signal injection scheme limit the applications of saliency tracking based sensorless control methods for interior permanent magnet synchronous machine (IPMSM) drives at low-speed operation. In this paper, a pseudorandom-frequency sinusoidal injection (PRFSI) considering the sample and hold effect in practical applications is proposed to reduce the undesired acoustic noises. Since the power spectral density (PSD) of the excited high-frequency (HF) current could be dispersed and continuously distributed with PRFSI, the additional HF acoustic noises can be reduced. Through the comparative analysis of HF response currents PSD results for PRFSI and fixed-frequency sinusoidal injection (FFSI), the principle of acoustic noises reduction with PRFSI is analyzed theoretically. Furthermore, the optimal selection of the injection signals is derived considering the sample and hold effect. Whereby, a comparative evaluation of the proposed PRFSI versus FFSI is carried out on a 2.2-kW position sensorless IPMSM drive, in terms of position estimation and PSD results, which verifies the effectiveness of the proposed scheme.

Pseudorandom-Frequency Sinusoidal Injection Based Sensorless IPMSM Drives With Tolerance for System Delays

This paper proposes an enhanced system-delay-tolerant signal processing method for high-frequency (HF) signal injection based position sensorless interior permanent magnet synchronous machine (IPMSM) drives. To reduce the acoustic noises induced by the HF response current using the conventional fixed-frequency sinusoidal injection based method, the pseudorandom-frequency sinusoidal injection strategy is proposed and comparatively evaluated in terms of the power spectral density of the phase current. Furthermore, the position estimation degradation caused by the system delay effects due to the pulsewidth modulation (PWM) update delay and the hardware delay using the common signal processing method, especially with the injection frequency increasing, is analyzed. On this basis, an enhanced system-delay-tolerant signal processing strategy is proposed. Through the normalization process for the HF response current and coordinate transform, the terms related to plant parameters and system delays can be cancelled. Therefore, the reliable saliency based method with a higher injection frequency can be achieved. The comparative evaluation on a 2.2-kW position sensorless IPMSM drive is carried out, which verifies the effectiveness of the proposed scheme.

A Phasor-Based Analysis of Sinusoidal Injection Locking in LC and Ring Oscillators

A new perspective into the locking behavior of LC and ring oscillators is presented. By decomposing a sinusoidal injection current into in-phase and quadrature-phase components, exact expressions for the amplitude and phase of an injection-locked LC oscillator which hold for any injection strength and frequency are derived and confirmed by simulation. The analysis, which can be naturally extended to an arbitrary LC resonator topology, leads to a rigorous understanding of the fundamental physics underlying the locking phenomenon. Furthermore, an investigation of the different necessary and sufficient conditions for injection locking to occur is carried out, leading to a more precise notion of the lock range. The ring oscillator is also analyzed in an analogous fashion, resulting in simple yet accurate closed-form expressions for the fractional lock range in the small-injection and long-ring regimes; the expressions are validated by simulations of single-ended inverter-based ring oscillators in 65-nm CMOS. The mathematics behind how the injection modifies the phase delay contributed by each stage in the ring is discussed. A corollary that generalizes the small-injection lock range to any feedback-based oscillator topology is established. Conceptual and analytical connections to the existing literature are reviewed.

Magnetohydrodynamic Three-Dimensional Couette Flow of a Second-Grade Fluid with Sinusoidal Injection/Suction

A mathematical model for magnetohydrodynamic (MHD) three-dimensional Couette flow of an incompressible second-grade fluid is developed and analyzed theoretically. The application of normal sinusoidal injection at the lower fixed plate and its equivalent deduction by suction through the uniformlymoving upper plate leads to three-dimensional flow.Approximate solutions for components of velocity, pressure and skin friction are obtained. The effects of flow parameters such as Hartmann number, Reynolds number, suction/injection parameter, non-Newtonian parameter on velocity components, skin friction factors along main flow direction and transverse direction, and pressure through parallel porous plates are discussed graphically. It is noted that Hartmann number provides a mechanism to stable the skin friction component along the main flow direction.

Couette flow of an incompressible fluid in a porous channel with mass transfer

The present discussion deals with the study of couette flow through a porous medium of a viscous incompressible fluid between two infinite horizontal parallel porous flat plates with heat and mass transfer. The stationary plate and the plate in uniform motion are subjected to transverse sinusoidal injection and uniform suction of the fluid. Due to this type of injection velocity, the flow becomes three dimensional. The analytical solutions of the nonlinear partial differential equations of this problem are obtained by using perturbation technique. Expressions for the velocity, temperature fields and the rate of heat and mass transfers are obtained. Effects of the following parameters Schmidt number (Sc), Modified Grashof number (Gm) on the velocity, temperature and concentration fields are obtained numerically and depicted through graphs. The rate of heat and mass transfer are also analyzed.

Resonance-like dynamics in radial cyclic injection flows of immiscible fluids in homogeneous porous media

Interfacial instabilities of immiscible radial displacements in homogeneous porous media are analysed in the case of sinusoidal injection flows. The analysis is carried out through numerical simulations based on the immersed interface and level set methods. Investigations of the effects of the period of the sinusoidal injection flows revealed a novel resonance effect where, for a critical period, the number of fingers as well as their structures are considerably changed. The resonance in the flow development is clearly identified through the abrupt changes in the Fourier spectrum of the interface as well as quantitative characteristics of the flow in the form of the minimum and maximum radii of the interface. For the range of parameters examined in this study that correspond to instabilities dominated by viscous forces, the resonance period was found to correlate with a characteristic time of the flow and the fluids mobility ratio. This new physical phenomenon offers new perspectives for using the flow instability to determine important physical properties such as the viscosity and the surface tension of fluids.

Magnetohydrodynamic Three-Dimensional Couette Flow of a Maxwell Fluid with Periodic Injection/Suction

A mathematical model for magnetohydrodynamic (MHD) three-dimensional Couette flow of an incompressible Maxwell fluid is developed and analyzed theoretically. The application of transverse sinusoidal injection at the lower stationary plate and its equivalent removal by suction through the uniformly moving upper plate lead to three-dimensional flow. Approximate solutions for velocity field, pressure, and skin friction are obtained. The effects of flow parameters such as Hartmann number, Reynolds number, suction/injection parameter, and the Deborah number on velocity components, skin friction factors along main flow direction and transverse direction, and pressure through parallel porous plates are discussed graphically. It is noted that Hartmann number provides a mechanism to control the skin friction component along the main flow direction.

Capacitance measurement method using sinusoidal voltage injection in isolating phase‐shifted full‐bridge DC–DC converter output stage

When it comes to the reliability of power electronics, wear-out caused by ageing of electrolytic capacitors is a major concern. The capacitor ageing presents indicators such as a decrease in the capacitance and an increase in the equivalent series resistance, the detection of which can be used for capacitor health monitoring. In this study, the measurement of the output stage capacitance in an isolating DC–DC converter output stage is shown, which is used to assess the capacitor condition. In addition to presenting the method, fundamental issues related to the traditional capacitor ageing detection are discussed. The proposed method uses a sinusoidal voltage injection into the output voltage, which generates a current through the output stage capacitor. The capacitance is evaluated by the capacitor impedance, which is defined by the amplitudes of the applied voltage and the resulting capacitor current with the injection signal frequency. The method does not require hardware modifications to the converter or the measurement system, and it is executed online during the converter operation. The results show that the method is able to detect changes in the output stage capacitance regardless of the load.

Stereophonic channel decorrelation using a binaural masking model

Traditional methods often only use monaural masking models to decorrelate input signals for stereo acoustic echo cancellation. Whereas, it seems more reasonable to use binaural masking models for the following two reasons. First, stereo signals are heard by two ears rather than just one. Second, psychoacoustic researchers have already shown that there are obvious masking level differences between binaural masking models and monaural masking models. By studying binaural masking level difference models, we first introduce a simplified binaural masking model for stereo acoustic echo cancellation. Considering that the interaural time difference is dominant at low frequencies (⩽1.5 kHz) and the interaural level difference is a major cue at higher frequencies, we propose to use different signal decorrelation schemes at these two frequency bands. In the low-frequency band, a pitch-driven sinusoidal injection scheme is proposed to maintain the interaural time difference, where the amount of injection is determined by the proposed binaural masking model. In the high-frequency band, a modified sinusoidal phase modulation scheme is applied to make a trade-off between preserving the interaural level difference and decorrelating the stereophonic input signals. Assessment results show that the proposed method can effectively improve the non-unique problem and retain good speech quality.

Implementation of a sensorless interior permanent magnet synchronous drive based on current deviations of pulse‐width modulation switching

This study proposes a rotor position estimating method by detecting the stator currents under each pulse-width modulation switching state for an interior permanent magnet synchronous motor drive system. The proposed sensorless motor drive system can be applied in an air conditioner without injecting any high-frequency sinusoidal or cosine voltage signal. The operating speed range can be effectively extended because the maximum available voltage is increased when compared to the high-frequency sinusoidal or cosine voltage injection method. The detailed analysis is discussed here. A digital signal processor, TMS-320-F-2812, is used to execute the rotor position estimator and controller. Several experimental results are included to evaluate the theoretical analysis. The experimental results show that the proposed sensorless method can provide satisfactory performance for a closed-loop interior permanent magnet synchronous motor drive system applied in an air conditioner.