• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.77-79
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• 2007

The phase angle of the utility voltage is used in current control of grid-tied fuel cell power converter. Therefore if the detection of phase angle is a problem, Current control is affected by the distorted phase angle. This paper presents a problem of synchronous reference frame PLL algorithm for single-phase systems and proposes compensated synchronous reference frame PLL algorithm. The proposed method helps power quality improvement of grid-tied fuel cell power converter under distorted utility conditions. Simulation and experimental results are presented to demonstrate the validity of the proposed method.

• Journal of Power Electronics
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• v.16 no.1
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• pp.18-26
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• 2016

This paper proposes a compensation algorithm for reducing a specific ripple component on synchronous reference frame phase locked loop (SRF-PLL) in grid-tied single-phase inverters. In general, SRF-PLL, which is based on all-pass filter to generate virtual voltage, is widely used to estimate the grid phase angle in a single-phase system. In reality, the estimated grid phase angle might be distorted because the phase difference between actual and virtual voltages is not 90 degrees. That is, the phase error is caused by the difference between cut-off frequency of all-pass filter and grid frequency under grid frequency variation. Therefore, the effects on phase angle and output current attributed to the phase error are mathematically analyzed in this paper. In addition, the proportional resonant (PR) controller is adapted to reduce the effects of phase error. The validity of the proposed algorithm is verified through several simulations and experiments.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.1
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• pp.70-76
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• 2000

This paper describes a one-chip micom controller and phase angle control method for self-starting and energy saving of single-phase induction motor. The proposed method is based on the optimal efficiency control which is running by variable phase angle of main winding current such as to maintain the maximum efficiency characteristics of the motor, in voltage control with TRIAC. Experiments are focused on a capacitor starting single-phase induction motor. The optimal energy saving by variable phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.120-130
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• 1999

In this paper, we show that the instantaneous phase current of the bifiler-wound hybrid stepping motor is dependent of lead angle and that the information of motor position is obtained from the instantaneous phase current at ${\pi}/2$ by the theoretical formular and its computer simulation results. From the facts, we design the microcontroller-based motor position sensorless controller of optimal lead angle, which generates the excitation pulses for the closed-loop drives. The controller is consist of microcontroller which has the function of A/D converter, programmable input/output timer, and the transfer table which has the values of optimal lead angle depending on motor velocity, and ROM which has the transfer table of the values of lead angle depending on velocity of motor and the values of instantaneous phase current at ${\pi}/2$. From the design of microcontroller-based controller, we minimize the external interface circuit and obtain flexibility by changing the contents of ROM transfer tables and the control software. We confirm that the designed controller drives the bifilar-wound hybrid stepping motor is the mode of optimal lead angle by comparing the instananeous phase current experimental results and computer simulation results.

• Journal of IKEEE
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• v.22 no.3
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• pp.716-722
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• 2018

This paper presents a voltage angle control strategy for surface permanent magnet synchronous motor (SPMSM) drives used in low-cost applications, wherein a current vector control is not employed. In the proposed method, the current vector control scheme, which requires high precision phase-current sensing units and a fast calculation capability of a motor drive controller, is replaced with the voltage angle controller. The proposed voltage angle controller calculates a d-axis voltage command to make the d-axis current zero by using a simple equation obtained from the voltage equation of SPMSM. The proposed method shows performance similar to the current vector controlled SPMSM drive during steady-states and its structure is very simple and thus it can be easily implemented with a low-cost microcontroller. The effectiveness of the proposed method is verified through simulations and experiments.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.2
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• pp.53-60
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• 2003

This paper deals with steady-state analysis of a single-phase line-start permanent magnet synchronous motor. In order to analyze the steady-state characteristics, the asymmetric single-phase line-start synchronous motor is converted to the symmetric two-phase synchronous motor, that is, the asymmetric magnetic field is separated from the positive and the negative symmetric components using symmetrical-component theory. The analysis method of the synchronous motor on the d-q axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Moreover, d-q axis inductance considering current phase angle is applied to positive component analysis for precise characteristic analysis. In order to validate the proposed analysis method, the analysis results are compared with the experimental results.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.350-352
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• 1995

The starting characteristics of single phase induction motor(SPIM) is described by control of phase and voltage. Auxiliary winding voltage is controlled by DC amplifier and phase is integrator. These processes enable comparison of torque with slip in each voltage and phase angle variations. Simulation and experimentation results of the motor's torque-slip characteristics using the controlled auxiliary winding voltage and phase angle arc shown and discussed. As a results, starting time is fast and main winding current is small when auxiliary winding voltage is low than rating voltage and starting characteristics is good in phase angle $90^{\circ}$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.11
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• pp.68-76
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• 2014

This paper presents an offset error compensation algorithm for the accurate phase angle of the grid voltage in single-phase grid-connected inverters. The offset error generated from the grid voltage measurement process cause the fundamental harmonic component with grid frequency in the synchronous reference frame phase lock loop (PLL). As a result, the grid angle is distorted and the power quality in power systems is degraded. In addition, the dq-axis currents in the synchronous reference frame and phase current have the dc component, first and second order ripples compared with the grid frequency under the distorted grid angle. In this paper, the effects of the offset and scaling errors are analyzed based on the synchronous reference frame PLL. Particularly, the offset error can be estimated from the integrator output of the synchronous reference frame PLL and compensated by using proportional-integral controller. Moreover, the RMS (Root Mean Square) function is proposed to detect the offset error component. The effectiveness of the proposed algorithm is verified through simulation and experiment results.

• Proceedings of the KIEE Conference
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• summer
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• pp.791-793
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• 2004

Voltage unbalance is generated by the load and impedance mismatching at the 3-phase 4-wire system of customer load. Voltage unbalance factor can be changed by the voltage amplitude or phase angle, and both. A small voltage unbalance is connected to high current unbalance. If the voltage unbalance is generated at the joint system of 1-phase and 3-phase load, Induction motor due to the current unbalance increase is generated loss, noise and torque ripple. In order to analyze the effect by voltage unbalance, it is necessary to the consideration of amplitude and phase angle. In this paper, We analyzed the effects that induction motor is affected by asymmetric voltage unbalance

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2526-2528
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• 1999

Parameters of equivalent circuit of IPMSM are varied according to current magnitude and current phase angle. Especially, Parameter variation of IPMSM for an electric vehicle(EV) is critical. Because current magnitude is very large. and current phase angle range also is wide. So, variation characteristics of $L_d$ and $L_q$ of the IPMSM are analyzed and verified through experiments. And then new parameter estimator of $L_d$ and $L_q$ that is constructed by neural network technique is suggested Using numerical method, the advanced characteristics of current controller of vector control algorithm is verified.