Yie-Tone Chen

A procedure for designing EMI filters for AC line applications

A procedure for designing AC power line EMI filters is presented. This procedure is based on the analysis of conducted EMI problems and the use of a noise separator. Design examples are given, and results are experimentally verified.

A Driver for the Single-Phase Brushless DC Fan Motor With Hybrid Winding Structure

This paper mainly proposes a novel driver for a single-phase brushless dc fan motor with a hybrid series/parallel winding structure. The winding symbols and directions of the hybrid motor stator structure are defined, and the winding steps for the proposed series/parallel winding are explained. An adequate inverter driving circuit, which is capable to simultaneously obtain the advantages of the hybrid structure, is also discussed. At last, the overall system of this hybrid brushless dc motor with the proposed driving circuit is then implemented to verify the performance of the proposed driver and structure.

Control-loop modeling of multiple-output feedback of forward converters

A small-signal model is developed for the forward converter with multioutput feedback. In the basis of the model developed, feedback compensation schemes are proposed to stabilize the circuit. The closed-loop circuit performances such as line regulation, cross regulation, and load regulation, are expressed analytically in terms of multiple-loop gains of the system. >

Analysis and design of a dimmable electronic ballast controlled by a switch-controlled capacitor

This paper presents the related principle and analysis of the dimmable electronic ballast controlled by the switch-controlled capacitor (SCC). A Fourier-series expansion is used to derive the operational principle of the zero-voltage-switching Class-D series-parallel-load-resonant dimmable electronic ballast regulated by the SCC. By the adaptation of the SCC, the lightness of the system can be adjusted, while the operation frequency of the Class-D converter can be kept constant. The dimmable effect controlled by the variable SCC is examined. The analytical results are verified by simulations and experiments. Furthermore, the design considerations for the dimmable electronic ballast with SCC control are also presented in this paper.

New multi-output switching converters with MOSFET-rectifier post regulators

A new multi-output switching power converter is proposed. The new power converter can reduce conduction losses and achieve tight regulation. The small-signal model of the new power converter has also been developed and experimentally verified. Based on the proposed scheme and the analysis of the small-signal model, high-performance and high-efficiency multi-output switching power converters can be achieved.

Paralleling magamp-postregulator modules with sliding-mode-control method

This paper presents the parallel application of the magnetic amplifier (magamp) postregulators with a sliding-mode control. The system can be robust and with fast dynamic response based on the sliding-mode control. The controller can be designed in the time domain directly, which makes the design strategy easier and realizable. When the load increases, the parallel operation is adequate to be adopted. With the sliding-mode control and proper current distribution, the output currents of the parallel modules can be same when the capacity of the individual module is equal. Even if the capacities of the modules are different, the module with more capacity can also provide more output current and work well. Therefore, the purposes of controlling the output current distribution and achieving the stability of output voltage based on this kind of control strategy are achieved. Simulations and experimental results show that the parallel modules of magamp postregulators with the sliding-mode control can obtain the well dynamic behavior and proper current distribution.

Small-signal modeling of magnetic amplifier post regulators with current-mode control

The continuous-mode and the discontinuous-mode small-signal dynamic models of the magamp post regulator using the external-reset and the self-reset methods with current-mode control are presented in this paper. Based on the developed models, the dynamic performance of the magamp post regulator can be expressed in terms of circuit parameters. A procedure for designing the feedback compensation is given and experiments were conducted to verify the models.

Small-signal analysis of a synchronous-switch post regulator with coupled inductors

A small-signal model of the synchronous-switch post regulator with coupled inductors is developed. Performance variations of the synchronous switch post regulator due to different coupling coefficients are investigated. Comparison of the multiple-output converter using the technique of post regulation with the multiple-output converter using the scheme of weighted-mode control is also discussed. Experiments are given to verify the validity of the proposed small-signal model.

Small-signal modeling of multiple-output forward converters with current-mode control

A small-signal model of current-mode multiple-output feedback forward power converter has been developed. Based on the model, control performances are analytically expressed, and a compensation scheme is proposed. Comparison of such control with other control schemes is also discussed.

A PSpice-compatible model of PWM IC for switching power converters with soft-start characteristic

A new PSpice-based model is developed for simulating the soft-start characteristics of switching power supplies. Three commonly-used control ICs: TL494; SG3525; and UC3825 are considered. Using this model, starting characteristics of power supply circuits can be simulated effectively even with popular personal computers.<<ETX>>