High-efficiency Switched-mode Power Research Articles

Down-hole switching-mode power supply using a remote CA start up pulse

Abstract The hydrocarbon industry leans heavily upon advanced technologies to extract oil and gas from greater depths and in harsher environments. The challenge to electronics manufacturers and designers is to make complex electronics work at the high temperatures, vibration, and extreme pressures encountered in these locations. Among the more critical electronic systems required for high temperature down-hole operations is high efficiency switching mode power supplies (SMPS). The use of high frequency switching permits not only decreasing the size of inductors and capacitors in the circuit design, but also obtaining typical power efficiencies up to 90%. Generally a SMPS is composed of a controller, a converter and silicon carbide (SiC) power switches. High temperature down-hole gauges operate with low voltages either 3.3V or 5.0V; however, wire-line surface power equipment utilizes higher voltages above 250 V CD. Hence, SMPS requires efficient power dissipation circuits to reduce the DC input voltage. This work describes a high temperature SMPS that has a DC input range from 150 V CD to 300 V CD, ± 6 V CD output voltages and 12 W total power. The SMPS design uses a CA start up pulse provided by a programmable surface power supply via a mono-conductor wire-line cable; subsequently, the SMPS sustains its operation by powering itself using one of the voltage outputs. The obtained laboratory tests results of the down-hole SMPS, using changes in temperature from 25 °C – 200 °C, provide a firm basis for testing and evaluating the DC-CD power supply in high temperature gauges in the field.

The Output Researching of a Cascaded Multilevel Class-D Power Amplifier

A high efficiency switch-mode power amplifier based on a cascaded multicell multilevel circuit topology is introduced in the paper. A multicell topology being operated in a unipolar phase-shifted PWM control to switch-mode amplifier system is introduced. After analysising a single-phase H-bridge unipolar PWM inverter’s output, the paper emphasis on the researching of the output of a Cascaded Multilevel Class-D Power Amplifier. The paper analyzes the advanced characteristic of the cascaded multilevel technique. Then a cascaded multilevel class-D power amplifier is built in the laboratory. The result of measurement shows a good following performance and stability.

Modified Polar Sigma-Delta Transmitter for Multiradio Applications

Radio transmitters capable of transforming variable envelope signals into constant envelope signals can be associated with high-efficiency switched mode power amplifiers. One of the techniques providing this conversion is Polar Sigma-Delta (ΣΔ) architecture. This approach provides efficient solution for high-dynamic signals, and, moreover, it offers flexibility in amultiradio environment. The overall concept of the polar ΣΔ transmitter is presented here along with novel modifications and improvements. Namely, when recombining the envelope and the phase signals, it is suggested to replace the analog mixing by a digital mixing. The impact of a frequency synthesizer with a switched loop bandwidth and its imperfections on the overall polar ΣΔ architecture is investigated as well. The Mobile WiMAX standard has been chosen for validation due to very high requirements in terms of power dynamics and the variable channel bandwidth. Simulation results are presented in this paper, and advantages and drawbacks of this novel approach are pointed here as well.

A New Self-Oscillating Inverter for Switch Mode Power Supplies

This paper presents a new transistor self-oscillating inverter suitable for high efficiency switch mode power supplies, which can operate directly from high voltages and is free from output transformer saturation problems due to transistor characteristic mismatch. It uses a half-bridge power circuit, consisting of two transistors in one limb and two capacitors in the other. Amongst several advantages of this configuration, the switching transistors need to withstand a minimum voltage equal to the dc supply only and not higher as in conventional circuits, while using only two transistors.

Ferrite Cores For Switching Regulator

In recent years, the growth of switched-mode power supply production has been truly remarkable. Applications for these efficient power sources have been found in computers, computer peripheral equipment, control devices, and other systems. With the rapid progress made in microelectronics, the need for ultracompact, high-efficiency switched-mode power supplies has spurred the development of smaller and smaller transformers and choke coils. Trends in development of new ferrite cores intended for use at frequencies above 100 kHz are described. The advances described herein may result in even higher frequency applications of switched-mode power supplies.