Space platform power system hardware testbed

The scope of the work on the NASA Space Platform includes the design of a multi-module, multi-phase boost regulator, and a voltage-fed, push-pull autotransformer converter for the battery discharger. A buck converter was designed for the charge regulator. Also included is the associated mode control electronics for the charger and discharger, as well as continued development of a comprehensive modeling and simulation tool for the system. The design of the multi-module boost converter is discussed for use as a battery discharger. An alternative battery discharger design is discussed using a voltage-fed, push-pull autotransformer converter. The design of the charge regulator is explained using a simple buck converter. The design of the mode controller and effects of locating the bus filter capacitor bank 20 feet away from the power ORU are discussed. A brief discussion of some alternative topologies for battery charging and discharging is included. The power system modeling is described

Analysis and design of a high power, digitally-controlled spacecraft power system

The progress to date on the analysis and design of a high power, digitally controlled spacecraft power system is described. Several battery discharger topologies were compared for use in the space platform application. Updated information has been provided on the battery voltage specification. Initially it was thought to be in the 30 to 40 V range. It is now specified to be 53 V to 84 V. This eliminated the tapped-boost and the current-fed auto-transformer converters from consideration. After consultations with NASA, it was decided to trade-off the following topologies: (1) boost converter; (2) multi-module, multi-phase boost converter; and (3) voltage-fed push-pull with auto-transformer. A non-linear design optimization software tool was employed to facilitate an objective comparison. Non-linear design optimization insures that the best design of each topology is compared. The results indicate that a four-module, boost converter with each module operating 90 degrees out of phase is the optimum converter for the space platform. Large-signal and small-signal models were generated for the shunt, charger, discharger, battery, and the mode controller. The models were first tested individually according to the space platform power system specifications supplied by NASA. The effect of battery voltage imbalance on parallel dischargers was investigated with respect to dc and small-signal responses. Similarly, the effects of paralleling dischargers and chargers were also investigated. A solar array and shunt model was included in these simulations. A model for the bus mode controller (power control unit) was also developed to interface the Orbital replacement Unit (ORU) model to the platform power system. Small signal models were used to generate the bus impedance plots in the various operating modes. The large signal models were integrated into a system model, and time domain simulations were performed to verify bus regulation during mode transitions. Some changes have subsequently been incorporated into the models. The changes include the use of a four module boost discharger, and a new model for the mode controller, which includes the effects of saturation. The new simulations for the boost discharger show the improvement in bus ripple that can be achieved by phase-shifted operation of each of the boost modules

DEPENDENCIES OF CURRENT HARMONICS OF SOME NONLINEAR LOAD DEVICES ON RMS SUPPLY VOLTAGE

The paper deals with the determination of current harmonic dependencies of some nonlinear load devices on the rms supply voltage. These dependencies are based on the laboratory experiments that include the variations of rms supply voltage in relatively wide ranges. The experiments were performed on some representatives of nonlinear load devices. Both current harmonic amplitudes and their angles are recorded during the voltage changes, and corresponding dependencies on rms voltage are obtained by curve fitting. The results are related to actual devices that are typically used in residential load sector. The obtained dependencies are the indices of potentially significant effects of rms voltage variation on current harmonics in low voltage installations

Impact of Voltage Variation on Domestic and Commercial Loads

This Thesis studies the impact of variations in supply voltage on various loads representing different types of loads. The scope of Thesis is analysis of active and reactive power used by appliances at different supply voltages varying from 90% up to 110% of rated value, as well as other factors that these variations influence. Previous studies showed that power consumption of certain device varies with changing of supply voltage, but most of them were dealing with 120V networks, and the other ones are outdated. This study provides ZIP models (polynomial of 2nd power with coefficients Z, I and P standing for constant impedance, current and power correspondingly) for typical house appliances, also results of induction motor heating test and analysis of typical household appliances mix. Results show, which of appliances can withstand voltage variations better, as well as give an idea what is power-voltage curve of the household and what is the percentage of economical losses. Also studies show that almost every device is able to maintain its operation during critical voltage deviations of 10% Using that data, it is possible to optimize energy usage and decrease losses. The results encourage continuing further investigation of devices with higher power and show the necessity of dynamic seasonal household model

Mariner Mars power system optimization study Final report

Optimum Mariner-class spacecraft electric power system providing improved utilization of solar array power and greater reliabilit

Mariner Venus 67 guidance and control system

Subsystems of Mariner Venus 67 spacecraft guidance and control syste

Design and implementation of a three-phase boost battery charger with PFC using CompactRIO control system : design, simulation and implementation of a 3-phase boost battery charger

In a plug-in hybrid electric vehicle, the utility grid charges the vehicle battery through a battery charger. For a three-phase grid supply voltage, three-phase boost rectifiers are commonly used as chargers. Bi-directional power transfer capability and unit power factor operation become desirable features due to the increasing power quality requirements on the grid-connected converters. The Voltage Oriented Control is one of the methods based on high performance dq-coordinate controllers which satisfies the increasing power quality requirements. The Voltage Oriented Control method for a three-phase boost rectifier has been designed, simulated and implemented. The system simulation is performed using Matlab/Simulink software as well as Labview. A feedforward decoupled current controller is designed along with a Pulse Width Modulation scheme to control the battery charging. The controller, consisting of a current controller and a DC-link voltage controller, is designed using a method called Internal Model Control. A National Instruments CompactRIO system is used for practical implementation. The system directly runs a Labview model to execute the control. The Labview files are developed for this purpose. A brief explanation of the system configuration is provided for the experimental system. ____________________________________________________________________________________________________________Los vehículos eléctricos e híbridos usan potencia de la red para cargar sus baterías y mientras lo hacen el sistema de tracción no está en uso. Debido a que el sistema de carga y el de tracción no están en uso al mismo tiempo, el inversor y el motor eléctrico pueden ser usados como rectificador evitando el uso redundante de componentes. Para hacer esto, un motor con dos juegos de devanados puede ser usado consiguiendo en el cargador una reducción considerable de peso, volumen y precio. El cargador propuesto en un cargador aislado de alta potencia que usa la mitad de los devanados del motor durante la carga usando el motor como si fuera un transformador. El uso de este motor especifico nos proporcionará aislamiento que será beneficioso por razones de seguridad. El objetivo principal de este proyecto fin de carrera es el diseño y la implementación de un cargador integrado para un coche eléctrico o híbrido con un nivel de potencia de 15 kW programando un control para el inversor que consiga tener un factor de potencia unitario.Ingeniería Industria

The ATS-6 power system: Hardware implementation and orbital performance

The Applications Technology Satellite-6 power system, a shunt-boost configuration, uses partial shunt regulation of the solar array and a boost regulator for control of battery power. Regulation is provided for three different operating modes: shunt, charge, and boost. This configuration achieves the highest efficiency of power transfer from the solar array to the loads. The excellent dynamic regulation and low output impedance of the power system virtually eliminated the problem of subsystem interactions on the power bus due to conducted interference from load current fluctuations. The performance of the power system continues to be excellent. The solar array degradation (18.5 percent) was less than the specified 20 percent in two years in spite of extreme cycling from -160 C to 60 C. A unique battery cycling regime of discharges varying from 5 percent to 60 percent daily is being encountered. During the second year, noneclipse discharges have occurred twice a day to depths of 35 percent and 45 percent. Battery performance was good with only a small decrease in end-of-discharge voltage. A recent test to evaluate capacity gave 12.4 AH (83% of the nominal capacity of 15 AH) after over 1400 battery discharge cycles. A small increase in the end-of-charge voltage has recently occurred necessitating a change in the charge regime to achieve full charge conditions

A New Isolated Multi-Port Converter With Multi-Directional Power Flow Capabilities for Smart Electric Vehicle Charging Stations

© 2018 IEEE. If the batteries are charged by clean renewable energy sources, electric vehicles (EVs) can have zero gas emission, contributing greatly toward the preservation of the green environment. In a smart micro-grid, EVs together with other distributed energy storage units can be used to supply electricity to the loads during the peak hours so as to minimize the effects of the load shedding and improve the quality of electricity. To achieve these goals, an isolated hybrid multi-port converter is required to control the power flows and balance the energy among renewable energy sources, EVs, and the grid. In this paper, a new isolated multi-port converter is proposed, which can control the power flow in multiple directions. The converter is modeled in the matlab/Simulink software environment and this validates the technology with a laboratory prototype test platform. The modeling, implementation, and results are discussed comprehensively