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A current mode analysis on ground leakage current noise generation in unbalanced and balanced switching converters
(2010-01-01)
Intachot, Terdsak
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Chuladaycha, Nontawat
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Prempraneerach, Yothin
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Nitta, Shuichi
This paper presents the new switching converter model used for analyzing the generation mechanism of ringing ground leakage (GL) current, generated during the transient, at switch on/off of any switching converter. By applying the Norton model, the proposed new model of switching converter can be formulated. The ringing GL current is evaluated at the switching on/off of the unbalanced (half-bridge converter) and the balanced converter (full-bridge converter) for bidirectional D.C. motor drive used as an example. It is concluded that the measured and simulated results of the generated GL current agree well with the numerical analysis results, analyzed by the proposed new model of switching converter, in terms of the minimum or maximum peak currents and the ringing frequency. Copyright © 2010 The Institute of Electronics, Information and Communication Engineers.
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Conductive common-mode noise reduction by system balance improvement on three phase inverter
(2008-09-19)
Boonpirom, Nimit
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Prempraneerach, Yothin
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Aunchaleevarapan, Kaison
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Nitta, Shuichi
This paper aims for the conductive common-mode noise reduction by system balance improvement on three phase inverter. The main objective is to improve the system balance on three phase inverter based on passive balance and active balance for common-mode noise reduction. As a result, the common-mode current which is generated by PWM switching voltage will be cancelled in frame ground. The concept of system balance and equivalent circuit on double-switch converter for three phase inverter is proposed. Furthermore, the experimental results of three phase induction motor drive by three phase inverter, that is both of time domain measuring and spectrum of common-mode noise measuring are employed respectively.
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A study on the system imbalance of the single-switch converter for the conductive common mode noise reduction
(2007-01-01)
Boonpirom, Nimit
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Prempraneerach, Yothin
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Paithoonwatanakij, Kitti
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Aunchaleevarapan, Kraison
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Nitta, Shuichi
This paper reduces system imbalance by replacing the single-switch converter with a synchronized double-switch converter based on two active switches technique and hybrid balance technique, including active balance and passive balance for common mode noise reduction. The system balance is experimentally evaluated by the common mode rejection ratio (CMRR). Finally, examples show that the CMRR of the single-switch converter is improved from 1.67 dB to 32.04 dB when the double-converter with two active switches technique is applied and to 41.5 dB when the double-switch converter with hybrid balance technique is applied. Copyright © 2007 The Institute of Electronics, Information and Communication Engineers.
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A high frequency stability of VCO with dual feedback loop
(2005-12-01)
Vibunjarone, Vichupong
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Prempraneerach, Yothin
This paper is purposed to improve the high frequency stability of the voltage controlled oscillator (VCO) with dual feedback loop. The proposed of closed loop VCO (CLVCO) is composed of PI controller in the forward part and in the feedback part the phase locked loop is used instead of a frequency to voltage converter (FVC) for some advantages, there is no need for a large frequency division element (1/N) in the feedback part. The other advantages of phase-locked loop is used as the feedback element, the high frequency bandwidth of a closed loop VCO is possibly designed. The CLVCO can greatly improved VCO characteristic such as faster speed response as well as higher operation bandwidth, to minimize the effect of the VCO noise and the power supply variation and also obtain better linearity of VCO output. The experimental results confirm the validity of the proposed CLVCO. © 2005 SICE.
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Improved noise reduction ability and frequency stability of VCO with external feedback loop
(2005-12-01)
Vibunjarone, Vichupong
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Prempraneerach, Yothin
This paper presents the integrated circuit combined with PI controller and the frequency to voltage converter (FVC) acting as the feedback part to be a closed-loop VCO circuit (CLVCO). The PI controller is designed by symmetrical optimum for optimum output response so as to minimize the effect of VCO noise. This closed loop circuit can achieve good frequency stability as well as good noise suppression. The experimental results show that CLVCO is independent from power supply variation and the frequency stability due to the effect of VCO noise or voltage drift which is greatly improved. © 2005 SICE.
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A new phase-locked loop system with the controllable output phase and the lock up time
(2005-12-01)
Vibunjarone, Vichupong
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Prempraneerach, Yothin
This paper, we propose a new phase-locked loop (PLL) system with controllable the output phase independent from the output frequency and lock-up time. This PLL system has a dual control loop is described, the inner loop greatly improves VCO characteristic. The main loop is the heart of this PLL, which greatly improves the output frequency instability due to the external high frequency noise coupling to the input reference frequency. This main loop has the two control inputs, the first one achieves to control the output frequency of the VCO and the other one is used to control the output phase independently from the frequency output as well as the lock-up time which can be controlled for optimum output response by this input. The experimental results confirm the validity of the proposed phase-locked loop. © 2005 SICE.
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Robust stabilization of uncertain linear system with distributed state delay
(1999-01-01)
Phoojaruenchanachai, Suthee
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Uahchinkul, Kamol
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Ngamwiwit, Jongkol
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Prempraneerach, Yothin
In this paper, we present the theoretical development to stabilize a class of uncertain time-delay system. The system under consideration is described in state space model containing distributed delay, uncertain parameters and disturbance. The main idea is to transform the system state into an equivalent one, which is easier to analyze its behavior and stability. Then, a computational method of robust controller design is presented in two parts. The first part is based on solving a Riccati equation arising in the optimal control theory. In the second part, the finite dimensional Lyapunov min-max approach is employed to cope with the uncertainties. Finally, we show how the resulting control law ensures asymptotic stability of the overall system.
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A method for contactless speed measurement of two-phase AC servomotors
(1983-01-01)
Prempraneerach, Yothin
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Pechpunsri, Wirog
A technique is presented for contactless angular speed measurement of two-phase AC servomotors. It is based on the measurement of the counter EMF of the motor, by balancing the voltage supplied to the motor by an amplifier against the counter EMF generated in the motor stator winding. The circuit is extremely simple, which minimizes cost, complexity and weight, and there is no requirement for mechanical coupling between motor and circuitry. The circuit can replace AC tachometers for speed measurement and for the provision of rate feedback in AC control systems. Circuit details and experimental results of the method are presented. © 1983 Taylor and Francis Group, LLC.

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