Although it has long been argued that electronic power converters can help improve system controllability, reliability, size, and efficiency, their penetration in power systems is still quite low. The often-cited barriers of higher cost and lower reliability of the power converters are quite high if power electronics is used as direct, one-to-one, replacement for the existing electromechanical equipment. However, if the whole power distribution system were designed as a system of controllable converters, the overall system cost and reliability could actually improve, as is currently the case at low power levels within computer and telecom equipment. Starting from the example of a computer power system, the paper contemplates possible future ac and dc electronic power distribution system architectures, especially in the presence of renewable energy sources. The proposed nanogrid-microgrid-…-grid structure achieves hierarchical dynamic decoupling of generation, distribution, and consumption by using bidirectional converters as energy control centers. This is illustrated by the description and simulation of static and dynamic operation of a dc nanogrid in a hypothetical future sustainable home. Several ideas for modeling, analysis, and system-level design of such systems, including power flow control, protection, stability, and subsystem interactions, are presented.

Future electronic power distribution systems a contemplative view

A Factorized Power Architecture (“FPA”) method and apparatus includes a front end power regulator (“PRM) which provides one or more controlled DC bus voltages which are distributed through the system and converted to the desired load voltages using one or more DC voltage transformation modules (“VTMs”) at the point of load. VTMs convert the DC bus voltage to the DC voltage required by the load using a fixed transformation ratio K=V out /V in and with a low output resistance. VTMs exhibit high power density, efficiency and, owing to their inherent simplicity and component utilization, reliability. VTMs may be paralleled and share power without dedicated protocol and control interfaces, supporting scalability and fault tolerance. Feedback may be provided from a feedback controller at the point of load to the front end or to upstream, on-board power regulator modules (“PRMs”) to achieve precise regulation.

Factorized power architecture with point of load sine amplitude converters

A power converter nearly losslessly delivers energy and recovers energy from capacitors associated with controlled rectifiers in a secondary winding circuit, each controlled rectifier having a parallel uncontrolled rectifier. First and second primary switches in series with first and second primary windings, respectively, are turned on for a fixed duty cycle, each for approximately one half of the switching cycle. Switched transition times are short relative to the on-state and off-state times of the controlled rectifiers. The control inputs to the controlled rectifiers are cross-coupled from opposite secondary transformer windings.

High efficiency power converter

The present development state in DC distributed power systems (DPS) is comprehensively reviewed in this tutorial. Basic distributed structures and their characteristics are described. The system level design considerations are discussed. The profile of current technologies is drawn. Finally, the issues and challenges in this research area are identified. These issues include not only improving efficiency, but also increased concerns regarding the cost and complexity of power supplying systems.

A review of distributed power systems part I: DC distributed power system

This paper presents an innovative design for a high efficiency, low profile, low voltage DC-DC power converter module intended for card mounted applications in a distributed aircraft power system. An innovative integrated magnetic structure for the half-bridge power converter lumps all the magnetic components into one structure and reduces the number of magnetic terminations. By incorporating advanced hybrid power packaging with the proposed integrated magnetic technique, a preliminary hybrid module of 1.6"/spl times/2.0" footprint and 0.21" height was developed. An overall efficiency (including the control circuit and power stage) of 90% was achieved for a 3.3 V, 100 W output operating at a 500 kHz switching frequency. The new integrated magnetic structure can be extended to other topologies.

Design of high efficiency, low profile, low voltage converter with integrated magnetics

This paper presents design considerations for power converter modules used in a distributed power system, including front-end power converter modules and load power converter modules. The system is designed for a universal input voltage of 90-260 V AC, with a bus voltage of 48 V DC. Several versions of the 600 W power factor corrected front-end power converter modules have been evaluated. One configuration includes a zero-voltage-transition PWM boost PFC circuit followed by a zero-voltage-switched active-clamp forward power converter. The second configuration uses an interleaved active-clamp flyback power converter for both the power factor correction and bus voltage regulation. 150 W and 300 W load power converter modules with 5 V output have been developed using the active clamp forward power converter topology and low-profile magnetics. >

R. Watson

Papers

Development of a DC distributed power system