Showing papers on "Power optimizer published in 1990"
Patent•
27 Sep 1990
TL;DR: In this article, a rectifier bridge consisting of rectifying devices (24, 25) connected to an AC source and providing a DC output to DC bus lines was proposed. But the authors did not consider the use of an external DC power source such as a battery.
Abstract: Power conversion apparatus for AC to DC to AC power conversion includes a rectifier bridge formed of rectifying devices (24,25) connected to an AC source (21) and providing a DC output to DC bus lines (27,28). A full bridge of active switching devices (30, 31, 34, 35) is connected across the DC bus lines to which a power source such as a battery (39) may also be connected. The load (36) and the AC power supply (21) share a common neutral line (33). The output of the bridge can provide AC output power to the load through a transformer (74). The power conversion apparatus allows full control of the currents on the load lines and AC input lines, even when the input and output are asynchronous. By providing an external DC power source such as a battery (39), uninterrupted power can be supplied to the load when the AC power source fails.
119 citations
Patent•
14 Aug 1990
TL;DR: A simplified elevator power system using an AC-DC converter, both to convert AC to DC during normal operation and to convert stored DC power to AC during power failures is presented in this paper.
Abstract: A simplified elevator power system using an AC-DC converter, both to convert AC to DC during normal operation and to convert stored DC power to AC during power failures. A power source monitoring relay monitors AC power coming from a utility, and upon power failure, switches a battery from a charging mode to a power source mode wherein DC power is supplied, not only to an inverter for driving a motor, but also to a converter hooked up to run as an inverter during such power failure in order to provide stepped-up AC voltage to elevator control devices. In this way, the prior art addition of an extra inverter is avoided.
48 citations
27 Nov 1990
TL;DR: In this article, a highly efficient power electronic converter for converting the output voltage of a solar panel or wind generator to the required DC battery bus voltage has been realized, where the converter is controlled to track the maximum power point of the nput source under varying input and output parameters.
Abstract: It is argued that a well-engineered renewable remote energy system utilizing the principal of maximum power point tracking (MPPT) can be cost effective, has a high reliability, and can improve the quality of life in remote areas. A highly efficient power electronic converter for converting the output voltage of a solar panel or wind generator to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the nput source under varying input and output parameters. MPPT for relatively small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor-based algorithm. Through field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. >
40 citations
27 Nov 1990
TL;DR: In this article, a small-scale photovoltaic system with storage batteries is described, which uses a resonant DC-DC power converter in order to clarify a desirable circuit condition.
Abstract: The system described is a small-scale photovoltaic system with storage batteries. A theoretical analyses is presented of the photovoltaic system using a resonant DC-DC power converter in order to clarify a desirable circuit condition. The experimental results of the battery charging characteristics are presented. >
17 citations
21 Oct 1990
TL;DR: The author considers different power distribution systems for telephone switching equipment, and some key figures are estimated that can be used when choosing which way to go.
Abstract: The author considers different power distribution systems for telephone switching equipment. Described are central distribution, decentralized distribution with one converter per shelf, and decentralized distribution with distributed on-board supplies. Besides a choice between a more central type of power supply and a distributed architecture, there is also a choice of whether the design shall be of an internal or external nature. The situation is examined, and some key figures are estimated that can be used when choosing which way to go. >
13 citations
11 Mar 1990
TL;DR: In this article, a high-density DC/DC converter module developed to be a fundamental building block in a distributed power architecture using a 50 V backplane bus is described, which exhibits an overall efficiency greater than 80% with an 18 MHz nominal switching frequency.
Abstract: A high-density DC/DC converter module developed to be a fundamental building block in a distributed power architecture using a 50 V backplane bus is described. A power density of 55 W/in/sup 3/ has been achieved using a high-frequency fully resonant circuit topology. The converter exhibits an overall efficiency greater than 80% with an 18 MHz nominal switching frequency. Other features of the converter are operation from -55 degrees C to 125 degrees C baseplate temperature and very low input/output ripple and EMI. >
12 citations
21 Oct 1990
TL;DR: A new power converter topology is proposed, essentially a four-quadrant converter offering several advantages, including high efficiency, reduced size and weight, excellent dynamic performance, and inherent galvanic isolation.
Abstract: A new power converter topology is proposed. The new converter is essentially a four-quadrant converter offering several advantages. These include high efficiency, reduced size and weight, excellent dynamic performance, and inherent galvanic isolation. The new topology proposed has the potential for a wide range of applications such as: inverters, rectifiers, and step-up step-down four quadrant converters for special applications. The key features as a rectifier are sinusoidal current absorption and unity power factor in both single-phase and three-phase operation. Special emphasis is given to the design of a 50 VA single-phase inverter for telecom applications (19 to 26 Hz ringing generator). The simplicity of the scheme proposed allows galvanic isolation between DC source and AC load without the requirement for a low-frequency transformer or DC/DC preregulating stage. In addition, a new diagram for a single-phase and three-phase rectifier based on the same principle is described in detail. >
9 citations
07 Oct 1990
TL;DR: In this article, the authors presented DC to DC power converter topologies that are suitable for high-density, high-power supplies, such as buck-boost operation, bidirectional power processing, capacitive commutation for switches, and unlimited high power capability.
Abstract: DC to DC power converter topologies that are suitable for high-density, high-power supplies are presented. Topological variations on the basic inverse dual converter (IDC) circuit, such as the coupled transformer and the multiphase and multipulse derivation of the single-phase IDC, are analyzed, and simulation results are discussed. The topologies have most of the IDC features, such as buck-boost operation, bidirectional power processing, capacitive commutation for switches, and unlimited high-power capability. The multiphase, the coupled transformer, and the power distribution IDC topologies offer additional properties, such as significant power-density improvement isolation. AC tapping, and input-current reduction. A quantitative comparison between the single- and the multiphase IDC is presented. >
7 citations
21 Oct 1990
TL;DR: The overall efficiency of the plant defined as the ratio of its output power to the maximum available photovoltaic power can be precisely evaluated under widely varying operating conditions.
Abstract: A measuring system of output characteristics of photovoltaic panels is described. This system is implemented as a maximum power point monitor (MPPM) that quasi-instantaneously determines the photovoltaic generator. This information is then used to compute the overall efficiency of the plant defined as the ratio of its output power to the maximum available photovoltaic power. In this way the performance of the maximum power point tracker and of the entire plant can be precisely evaluated under widely varying operating conditions. The MPPM is an efficient development and control tool, particularly useful when different maximum power point tracking strategies are being compared. It is intended primarily for battery chargers and, generally, for DC-DC power converters but can easily be adapted for use with inverters. >
2 citations
07 Oct 1990
TL;DR: In this article, a DC/DC power converter that is capable of generating high voltage is described, which employs capacitive energy transfer to accomplish voltage conversion, achieving a transfer gain of 36.
Abstract: A DC/DC power converter that is capable of generating high voltage is described. The design employs capacitive energy transfer to accomplish voltage conversion. The converter contains arrays of integrated-circuit power switches and capacitors. A transfer gain of 36 is achieved, making it possible to step up a nominal input of 67.5 V DC to 2430 V DC. The circuit configuration, performance characteristics, and merits of the design are discussed. >
1 citations
12 Aug 1990
TL;DR: In this article, two wind power models are developed to compute the amount of wind power from wind turbines in different configurations and the impact of placing multiple WTGs in clusters to get higher power levels are investigated.
Abstract: Clusters and arrays of wind turbine generators (WTG) can be used to produce large-scale electric power which potentially presents an attractive alternative to electric utilities for meeting their load demands. This also means, substantial savings of conventional fuel and capacity. To bring about a conventional capacity displacement, wind power must itself have firm capacity. Two wind power models are developed to compute the amount of wind power from wind turbines in different configurations. The impact of placing multiple WTGs in clusters to get higher power levels are investigated. The advantages evolving out of site dispersal are also examined. In general terms, arrays of wind farms produce some firm capacity because of the diversity of wind at the dispersed sites. Methods for determining capacity credits earned for each scenario are presented in detail using a utility reliability model. The analysis is extended to include the competition against conventional expansion plants.
01 Jan 1990
TL;DR: In this article, a highefficient power electronic converter, for converting the output voltage of a solar panel, or windgenerator, to the required DC battery bus voltage has been realized.
Abstract: A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking (MPPT) can be more cost effective, has a higher reliability and can improve the quality of life in remote areas. A highefficient power electronic converter, for converting the output voltage of a solar panel, or windgenerator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3 - 5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply (RAPS) systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control.
01 Jan 1990
TL;DR: In this article, the relative merits of dc and ac distribution are discussed and specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison, and specific topologies were recommended for use in DC and ac systems.
Abstract: The electric power distribution systems for spacecraft are compared concentrating on two interrelated issues: the choice between dc and high frequency ac, and the converter/inverter topology to be used at the power source. The relative merits of dc and ac distribution are discussed. Specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison. Finally, specific topologies are recommended for use in dc and ac systems.