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Yachiangkam, Samart,Sangswang, Anawach,Naetiladdanon, Sumate,Koompai, Chayant,Chudjuarjeen, Saichol The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
This paper presents a steady-state operation analysis of full-bridge series-resonant inverters focusing on the distorted load current due to low-quality-factor resonant circuits in induction heating and other applications. The regions of operation based on the zero-voltage switching (ZVS) and non-zero-voltage switching (NON-ZVS) operations of the asymmetrical voltage-cancellation control technique are identified. The effects of a distorted load current under a wide range of output powers are also analyzed for achieving a precise ZVS operating region. An experimental study is performed with a 1kW prototype. Simulation and experimental studies have confirmed the validity of the proposed method. An efficiency comparison between the variable frequency method and the conventional fixed-frequency method is provided.
Jittakort, Jirapong,Sangswang, Anawach,Naetiladdanon, Sumate,Koompai, Chayant,Chudjuarjeen, Saichol The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5
Flexibility in the power control of ultrasonic transducers has remained a challenge for cleaning applications. This paper introduces a modification of the existing piezoelectric ceramic transducer (PCT) circuit to increase the range of operation through its impedance characteristics. The output power is controlled using the asymmetrical voltage-cancellation (AVC) method. Together with a phase-locked loop control, the switching frequency of the inverter is automatically adjusted to maintain a lagging phase angle under load-parameter variations during the cleaning process. With the proposed modification, the region of the zero-voltage switching (ZVS) operation is extended, which results in a wider range of output power control. A hardware prototype is constructed and the control algorithm is implemented using an STM32F4 microcontroller. Simulation and experimental results are provided to verify the proposed method for a 50-W PCT. The operating frequency and output power ranges under study are 37 - 41 kHz and 15.8 - 50 W, respectively.
Parinya, Panom,Sangswang, Anawach,Kirtikara, Krissanapong,Chenvidhya, Dhirayut The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.3
This paper proposes an alternative method to evaluate the effect of wind power to the power system stability with small disturbance. Alternatively, available techniques for stability analysis of a power system based on deterministic methods are less accurate for high penetration of wind power. Numerical simulations of random behaviors are computationally expensive. A stochastic stability index (SSI) is proposed for the power system stability evaluation based on the theory of stochastic stability and energy function, specifically the stochastic derivative of the relative well-defined energy function and the critical energy. The SSI is implemented on the modified nine-bus system including wind turbines under different conditions. A doubly-fed induction generator (DFIG) wind turbine is characterized and modeled using measured wind data from several sites in Thailand. Each of the obtained wind power data is analyzed. The wind power effect is modeled considering the aggregated effect of wind turbines. With the proposed method, the system behavior is properly predicted and the stability is quantitatively evaluated with less computational effort compared with conventional numerical simulation methods.
Panom Parinya,Anawach Sangswang,Krissanapong Kirtikara,Dhirayut Chenvidhya 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.3
This paper proposes an alternative method to evaluate the effect of wind power to the power system stability with small disturbance. Alternatively, available techniques for stability analysis of a power system based on deterministic methods are less accurate for high penetration of wind power. Numerical simulations of random behaviors are computationally expensive. A stochastic stability index (SSI) is proposed for the power system stability evaluation based on the theory of stochastic stability and energy function, specifically the stochastic derivative of the relative well-defined energy function and the critical energy. The SSI is implemented on the modified nine-bus system including wind turbines under different conditions. A doubly-fed induction generator (DFIG) wind turbine is characterized and modeled using measured wind data from several sites in Thailand. Each of the obtained wind power data is analyzed. The wind power effect is modeled considering the aggregated effect of wind turbines. With the proposed method, the system behavior is properly predicted and the stability is quantitatively evaluated with less computational effort compared with conventional numerical simulation methods.
Jirapong Jittakort,Anawach Sangswang,Sumate Naetiladdanon,Chayant Koompai,Saichol Chudjuarjeen 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5
Flexibility in the power control of ultrasonic transducers has remained a challenge for cleaning applications. This paper introduces a modification of the existing piezoelectric ceramic transducer (PCT) circuit to increase the range of operation through its impedance characteristics. The output power is controlled using the asymmetrical voltage-cancellation (AVC) method. Together with a phase-locked loop control, the switching frequency of the inverter is automatically adjusted to maintain a lagging phase angle under load-parameter variations during the cleaning process. With the proposed modification, the region of the zero-voltage switching (ZVS) operation is extended, which results in a wider range of output power control. A hardware prototype is constructed and the control algorithm is implemented using an STM32F4 microcontroller. Simulation and experimental results are provided to verify the proposed method for a 50-W PCT. The operating frequency and output power ranges under study are 37 - 41 kHz and 15.8 - 50 W, respectively.
Samart Yachiangkam,Anawach Sangswang,Sumate Naetiladdanon,Chayant Koompai,Saichol Chudjuarjeen 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
This paper presents a steady-state operation analysis of full-bridge series-resonant inverters focusing on the distorted load current due to low-quality-factor resonant circuits in induction heating and other applications. The regions of operation based on the zero-voltage switching (ZVS) and non-zero-voltage switching (NON-ZVS) operations of the asymmetrical voltage-cancellation control technique are identified. The effects of a distorted load current under a wide range of output powers are also analyzed for achieving a precise ZVS operating region. An experimental study is performed with a 1kW prototype. Simulation and experimental studies have confirmed the validity of the proposed method. An efficiency comparison between the variable frequency method and the conventional fixed-frequency method is provided.
Jirapong Jittakort,Samart Yachiangkam,Anawach Sangswang,Sumate Naetiladdanon,Chayant Koompai,Saichol Chudjuarjeen 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5
The variable-frequency asymmetrical voltage-cancellation (VFAVC) control is proposed in this paper to control the output power for a series resonant load with a full-bridge inverter for home appliance as induction cooking. The asymmetrical voltage-cancellation is used for controlling the output power. With the low quality factor loads, a fixed-frequency control might lead to non-zero-voltage-switching (NON-ZVS) operation. The proposed control strategy ensures the ZVS operation for switching loss reduction by varying the switching frequency slightly higher than the resonant frequency. By using the ZVS constant, the new control strategy is proposed by varying the switching frequency according to the output power. Moreover, this proposed control can improve the overall efficiency of inverter system. The experimental results are given in this paper to verify the proposed control method.
Nopporn Patcharaprakiti,Krissanapong Kirtikara,Veerapol Monyakul,Dhirayut Chenvidhya,Jatturit Thongpron,Anawach Sangswang,Ballang Muenpinij 한국물리학회 2010 Current Applied Physics Vol.10 No.3
This paper proposes a new method to modeling a power inverter of grid-connected photovoltaic system by using a nonlinear system identification technique based on the Hammerstein–Weiner model. In this method, the system is considered as a black box of which it is not necessary to know structures and parameters inside. A nonlinear system identification, which is composed of nonlinear blocks and linear blocks, has been processed and synthesized yielding the modeling from only measured inputs and outputs of the system. An inverter of a grid-connected photovoltaic system has been tested and its model determined. Results on modeling the voltage, current and power waveforms have accuracies of 98.13%,95.02% and 91.05% respectively. The mathematical model being the representation of the system can be analyzed and provide characteristics on controllability, stability, power quality, power flow.