• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.357-359
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• 1995

In this paper, vector control of induction motor drives using space current vector PWM is presented. The scheme gives advantages, besides robustness to inverter arm-shoot, sinusoidal input current and voltage for induction motors. In addition, space vector PWM for CSI produces faster transient response than conventional pattern PWM. Also, a modulation index control is proposed.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.6
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• pp.488-493
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• 2014

This paper presents a carrier-based pulse-width modulation(PWM) method for reducing the common-mode voltage of a three-level four-leg converter. The idea of the proposed PWM method is intuitive and easy to be implemented in digital signal processor-based converter control systems. On the basis of the analysis of space-vector PWM(SVPWM) and sinusoidal PWM(SPWM) switching patterns, the fourth leg pole voltage of the three-phase converter called "f leg pole voltage" is manipulated to reduce the common-mode voltage. To synthesize f leg pole voltage for the suppression of the common-mode voltage, positive and negative pole voltage references of f leg are calculated. An offset voltage is also deduced to prevent the distortion of a, b, and c phase voltages. The feasibility of the proposed PWM method is verified by simulation and experimental results. The common-mode voltage of the proposed PWM method in peak-to-peak value is 33% in comparison with that of the conventional SVPWM method. The transition number of the common-mode voltage is also reduced to 25%.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.4
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• pp.356-362
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• 2015

This paper presents a current control strategy in the synchronous reference frame for a single-phase PWM converter, which ensures sinusoidal input current control under the distorted source voltage and frequency condition. Given that the distorted source voltage distorts the phase angle for PWM converter control, the input current contains the same harmonics as the source voltage. Aside from the distorted voltage, the variation in source frequency reduces the performance of input current control. To achieve sinusoidal input current control under the distorted source voltage and frequency condition, this paper proposes a compensation strategy of current reference with the distortion component extracted from the phase angle and a detection strategy of frequency variation from the output of a synchronous reference frame phase-lock loop. The experimental results confirm the validity of the proposed method under the distorted source voltage and frequency condition.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.466-476
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• 2011

In this paper, a high-performance current control for the single-phase PWM converter under distorted source voltages is proposed using a composite observer. By applying the composite observer, the fundamental and high-order harmonic components of the source voltage and current are extracted without a delay. The extracted fundamental component is used for a phase-lock loop (PLL) system to detect the phase angle of the source voltage. A multi-PR (proportional-resonant) controller is employed to regulate the single-phase line current. The high-order harmonic components of the line current are easily eliminated, resulting in the sinusoidal line current. The simulation and experimental results have verified the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.71-73
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• 1995

For the accurate analysis of induction motors driven by PWM-type inverter, a time-stepping finite element method is presented in this paper. Since the PWM-type source voltage is not sinusoidal, the time harmonic method can not be used. Therefore, we used a time-stepping method, where the space harmonics due to the slot structure can be analyzed and each time-step size is determined from each increase of rotor position. As a numerical example, an induction motor of 20 Hp, 3 phase and 6 pole is analyzed. First, numerical results of the time-stepping finite element analysis are compared to those of conventional equivated circuit analysts. Next, the stator current characteristic obtained from PWM voltage source is compared to that from sinusoidal voltage source.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.928-933
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• 1998

This paper presents a novel current control system to eliminate the steady state control error and to improve the transient characteristics for PWM AC-DC converter. A general mathematical model of the converter that is represented as a state-space model is first established. The state-space model is used for the simulation of PWM switching converter with the proposed current control system. The proposed sinusoidal tracking control system that does not require coordinate transformations using principle of the integral controller is described. It is proved that the steady state deviation reduces to zero through a transfer function of source current control system. Finally, it is seen that simulations agree with the experimental results in source current and reference of controlled ac current loop.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1076-1078
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• 2001

In this paper, we studies PWM control method for 400kVA inverter. This method is compared with the conventional sinusoidal modulation method applying to the power converter with large capacity. The inverter controls a PWM modulation using a DSP processor.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.518-521
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• 1989

Recently, PWM cycloconverters that are frequency conversion system have been studied for eliminating do links of conventional converter and inverter systems. A new real-time method for generating PWM patterns is proposed in this paper. This method realizes sinusoidal input and output currents, controllable input displacement factor regardless of load power factor, and maximum output voltage range. Finally, feasibility of the proposed method is confirmed by simulation and experiments.

• Journal of Advanced Marine Engineering and Technology
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• v.11 no.2
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• pp.37-50
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• 1987

In an effort to conserve electric power, variable voltage variable frequency pulse width modulated (PWM) inverters are being applied increasingly to the variable speed control of the induction motors. The use of the PWM technique in motor drive applications is considered advantageous in many ways. For industrial applications, the PWM drive obtains its DC input through simple uncontrolled rectification of the commercial AC line and is favored for its good power factor, good efficiency, its relative freedom regulation problem, and mainly for its ability to operate the motor with nearly sinusoidal current waveforms. The purpose of this paper is to design a three phase natural sampled PWM inverter using microprocessor with simple control algorithm and hybrid control circuit has been built to implement this PWM scheme. In this system, the microprocessor can be used only for calculations directly related to motor control tasks by the design of hybrid circuit which sends PWM signals to the motor.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.214-218
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• 1991

This paper presents a PWM controlled cycloconverter with a DC resonant circuit for Induction heating. This cycloconverter converts commercial frequency power to high frequency power directly. So conversion efficiency improved. Controlling a input reactive power regardless of load power, it has sinusoidal input current waveforms as well as a input. displacement factor at 1.