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A power converter control technique is described in which digital circuits, discrete proportionalintegral- differential feedback, and duty ratio quantization are used to provide dynamic regulation. A time domain computer modeling technique is presented. Analytical results are compared to experimental results. Digital methods for output current limiting and soft-start are described. Output quantization...
An interactive, menu-driven computer program has been developed to analyze the small signal performance of electrical power systems. The Small Signal AC (SSAC) program enables the analysis of an arbitrary power system configuration using generic components. A component may be specified in terms of canonical circuit parameters or by selecting the entire component from a library. New component models...
Two general types of remote power controllers (RPC's), which combine the functions of a circuit breaker and a switch, were developed for use in direct-current (dc) aerospace systems. Powerswitching devices used in these designs are the relatively new gate-turnoff thyristor (GTO) and power metal-oxide-semiconductor field-effect transistors (MOSFET). The various RPC's can switch dc voltages to 1200...
The Giotto mission profile imposes peculiar constraints on the design of the spacecraft as well as on the design of the power subsystem. The Giotto PSiS is highly advanced both for the control concepts adopted and for the state-of-the-art components used. The overall subsystem reliability has been the other key design parameter. This paper describes the power subsystem configuration and the design...
ADC/DC converter adopting some new concepts about the synchronization of a free-running inverter is described. The DC/DC converter has been designed for Intelsat VI Satellite to supply CTU (Central Telemetry Unit) and RTU (Remote Telemetry Unit). The converter circuit is conventional, but emphasis will be placed on the synchronization technique which is characterized by its simplicity, reliability...
In this paper a low cost and low power inverter for domestic and solar applications is proposed. The prototype carried out obtains a low harmonic content in the output voltage waveform due to the special multiprimary transformer together with the optimal delayed values for the switching transistors. Special requirements are selected in order to take in a wide range of protections.
Developed to evaluate a solar array design, this computer tool is capable of modelization of Si and Ga As cells (as a function of physical parameters, temperature and radiation fluences), identification from measurements, evaluation of operating point with respect to given loads and to orbital position (LEO, GEO or GTO).
The power systems and the electrical distribution of existing geosynchronous telecommunication spacecrafts are evaluated through 13 typical examples. The comparative study put in evidence the advantage of limiting the bus voltage excursion for the payload.
Developed to compute the power profile of LEO satellites, this computer tool takes into account the stations visibility areas (ground based or GEO relays) the coverage of geographical zones defined by points, and logical conditions of equipments (swath angles, preheating, logical interdépendance). The results are visualized through power curves and earth maps.
This paper describes a converter whose purpose is to feed an χ-rays tube (25 KW, 140 KV) from the industrial main power supply (380 V, 50 Hz). The authors justify the structure of this generator that is constituted by an inverter using power transistors and a transformer-voltage multiplier set which are connected by a series resonant circuit. The control logic of the transistors gives them the dual...
A sequential switching shunt regulator system is analysed using the time domain method. Important parameters are specified and the effects of amplifier and loop delays are examined. System respnse to transients is modelled and a comparison of results is made.
The notion of the controlled quantity and the analysis of the nature of the cell output voltage culminate in a cell model with extended frequency validity. It is of a simple, invariant topology, defined by the cell characteristic coefficients. Its generality and conceptual and mathematical simplicity qualify it as the most convenient, comprehensive and coherent means for the cell systematization and...
The criteria of stability and response, as measured by the phase margin, and the frequency of the zero dB crossing are crucial to the successful design of the control circuitry of any power supply, including switching regulators. Using several unpublished techniques, these performance functions were written in a form suitable for ASTAP, so that their sensitivities with respect to the statistically...
In modelling PWM voltage-regulator dynamics the circuit is assumed to be a linear time-variant system and width-modulation action on the output fil ter is represented by a suitable set of impulse generators applied at each switching instant. Once the feedback-loop is open the "comb" function of its characteristic response can be expressed by means of a recursive matrix relation; the latter...
The design and development presented in this paper are the results of a programme, founded by ESA/ESTEC and perfonred by Christian Rovsing A/S af 1984, to design, build and test a representative section of a Pyrotechnic Arming and Firing unit and to establish an overall pyrotechnic system design concept, which is carrr patible with Ariane and Space shuttle launchers and launch sites. The design is...
After a short presentation of the HIPPARCOS satellite, the electrical system trade-offs which have led to the use of an AC Power Distribution for HIPPARCOS, are exposed. The inverter and the AC/DC modules using power FET's and synchronous rectification are described. Based on the HIPPARCOS Experience, some conclusions are drawn at system level and a philosophy for future satellites is proposed.
The electronic power conditioner (EPC) design for 230W RF 12 GHz TWTs is presented. Particular emphasis is devoted in evidencing the bus and tube interface problems, the technological aspects versus the very severe environmental requirements and the protection philosophy. In fact the EPC has to handle a very high power (~600 W), to provide outputs voltages up to 7.5 KV, to guarantee high stability...
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