Evaluation of the steady state performance of a squirrel cage induction motor using per-phase equivalent circuit

The performance evaluation of cage induction motor continues to receive tremendous attention because of its vital effect on the overall system stability. The model has predicted the behavior of cage induction motor under different operating conditions and in selecting the appropriate motor for a specific load application. There is often a challenge when a squirrel cage induction motor is connected to a time-varying load, particularly when the motor is selected without considering the effects of pulsating torques. The usual method used for steady state analysis of induction motors is the equivalent circuit method. Using the per phase equivalent circuit of the induction motor, stator current and referred rotor current were computed using simple circuit analysis. Once the currents are available, then power can be computed because the voltage is already known.

Equivalent circuit of a ferrite-wound inductor in a wide frequency range (0 Hz – 500 MHz)

Based on the measured impedance of the inductors wound on various ferrite cores and with a different number of turns, an equivalent high frequency (0 Hz 500 MHz) circuit model was built. The equivalent circuit model was built taking into account the physical processes occurring in the inductor: effect of wire resistance, effect of core material, mutual effect of wire and core material. The attempt explaining why the frequency characteristics (modulus and phase) of the inductor complex impedance have such a character in a wide frequency band (up to 500 MHz) was made. It was shown that for constructing an equivalent circuit model (structure and parameters), measuring only the inductors resistance modulus is not enough. It is also necessary to measure the phase of the inductor complex resistance, which is ignored in many works on the synthesis of an e inductor equivalent circuit.

Evaluation of Fano resonance and phase analysis of plasma induced transparency in photonic nanostructure based on equivalent circuit analysis

Fano resonance and plasma induced transparency (PIT) have been widely observed in various plasmonic nanostructures. Fano resonance takes place in weak coupling regime where coupling constant between two electromagnetic modes is lower than damping constant of system. Hence, extracting coupling and damping coefficients from resonance spectrum is the key to distinguish between Fano resonance and other resonances. In this paper, we propose a simple and realizable coupled LC circuit to analyze Fano resonance and PIT. Weak and strong coupling regime are distinguished by comparing coupling constant with damping constant. Meanwhile, we gain deep insight into Fano resonance and PIT in circuit by analyzing circuit phase and understand their connection with resonance in photonic structure. Furthermore, we extend the equivalent circuit model to the field involved short-range plasmon polarization or multi-orders dark modes. Since there are no specific parameters associated with photonic nanostructure, the proposed equivalent circuit can be used in most plasmonic resonance system as an universal model.

Establishing an Equivalent Circuit of a Quasihomogeneous Discharge Atmospheric-Pressure Plasma Jet with a Breakdown-Voltage-Controlled Breaker and Power-Supply Circuit

To simulate the I-V diagram of plasma homogeneous and filamentary discharge with equivalent circuit model more accurately, this study employed a breaker and passive circuit components and calculated the discharge parameters, such as equivalent discharge resistances and potential distribution etc., in atmospheric-pressure plasma jet (APPJ). In addition, this study calculated the gas-gap and dielectric capacitances of the APPJ and added a power supply equivalent circuit. Compared with other circuit models that adopted switches or a time-controlled current source to simulate the discharges, our present circuit model used a breakdown-voltage-controlled breaker for the homogeneous discharge and resistors with high-frequency switches for the filamentary discharge. We employed potential simulation to obtain the equivalent dielectric capacitance in the APPJ and then derived the gas-gap capacitance. We also replaced the ideal sine wave power supply with the equivalent circuit of the common double-peak-waveform power supply. The MATLAB Simulink was used to construct an equivalent circuit model and the discharge area ratio, breakdown voltage and filamentary equivalent resistance were obtained via I-V waveform fitting. We measured the plasma I-V waveform with a 20-kHz frequency, various voltages (6, 12, and 15 kV), a gas flow rate of 30 SLM, and two types of gas (Ar and He). The simulated and experimental I-V waveforms were very close under different conditions. In summary, the proposed equivalent circuit model more meaningfully describes the plasma physics to simulate homogenous and filamentary discharge, achieving results that were compatible with our experimental observations. The findings can help with investigating plasma discharge mechanisms and full-model simulations of plasma.