S.H. Chung

Publications (2)0 Total impact

• Source

  Available from: kskelvin.net

  Conference Proceeding: Boundary Control of Inverters Using Second-Order Switching Surface

  K.K.S. Leung, J.Y.C. Chiu, H.S.H. Chung
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  ABSTRACT: Concept of using a second-order switching surface in the boundary control of inverters is derived in this paper. The switching surface is formulated by estimating the state trajectory movement after a switching action. It results in a high state trajectory velocity along the switching surface. This phenomenon accelerates the trajectory moving towards the target operating point. Time-domain responses of the inverter with the proposed boundary control method under large-signal variations have been analyzed. The proposed control scheme has been successfully applied to a 100 W full-bridge inverter. Practical implementation of the system is provided. Dynamic responses of the inverter supplying to different kinds of loads, including a resistive load, an inductive load, and a diode-capacitor rectifying circuit, have been studied. Experimental results show that the inverter output voltage can attain a low total harmonic distortion at different load conditions and fast response to a large-signal load disturbance and an output reference voltage change
  Power Electronics Specialists Conference, 2005. PESC '05. IEEE 36th; 02/2005
• Conference Proceeding: Parameter monitoring of high-frequency electronically operated discharge lamp systems

  D.Y. Qiu, S.Y. Hui, S.H. Chung
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  ABSTRACT: Arc discharge loads such as discharge lamps require high ignition voltage (several kilo-volt to 20 kilo-volts), but have low on-state voltage (typically 100 V). For discharge arc monitoring purposes, it is difficult or uneconomical to implement voltage sensor to cover such a wide range of voltage. In this paper, a nonintrusive and electrically isolated method, based on the single-sensor principle, is used to derive the system parameters and variables for system monitoring and control purposes. Only one coupled winding is used to derive the converter inductor voltage, from which the lamp power, lamp arc resistance and inverter DC link voltage can be accurately derived. The proposal is verified with good agreement between derived values and measurements in an electronic ballast-fluorescent lamp system. The proposal can be useful in applications in which sensing the voltage across the load is either difficult or costly.
  Power Electronics Specialist Conference, 2003. PESC '03. 2003 IEEE 34th Annual; 07/2003