Novel transformer active filters
Novel transformer active filters are proposed to obtain high attenuation of voltage or current ripple without deteriorating the transient response of the system considered. Experimental results show that the scheme gives good steady-state performance of the power supply. >
A direct digital control for the phase-controlled rectifier
Direct digital control of the phase-controlled rectifier (PCR) is implemented with a minimum control hardware structure. A digital phase-locked voltage control (PLVC) without detecting the line voltage is presented. An inner fast control loop is proposed to stabilize the PCR system and to obtain its constant loop gain. In the inner loop, an averaging function is introduced to feed back the average DC voltage of the PCR output without the feedback filter. Its synchronism is modeled and analyzed. An optimal constant digital integral, proportional, and measurable variable feedback (IPM) current controller with a time-multiplied performance index is also proposed to obtain a good dynamic response of the output current. All control functions are implemented with an Intel 8797 single-chip microcomputer. Experimental results show that the scheme gives good dynamic and static performance for the PCR system. >
A new power measuring circuit using a bridge-connected magnetic circuit and another magnetic core
The authors describe the operating characteristics of an oscillating circuit using a bridge-connected magnetic circuit and another magnetic core. A square-shape output voltage is obtained in the oscillating circuit. The pulsewidth in positive and negative half cycles of output voltage changes with the current of the U-form core windings and with the signal voltage applied to the exciting windings. The mean value of the output voltage varies in proportion to the product of the current and the signal voltage. Utilizing this feature, an application of the oscillating circuit to a novel power measuring circuit of simple construction is presented. >