Showing papers on "Maximum power point tracking published in 1977"

Power maximization circuit

Abstract: A power maximization circuit periodically samples the output power of a power supply to regulate output voltage or current toward that resulting in maximum output power. Power increasing variations in voltage or current are continued until maximum power is reached and exceeded, at which time the direction of variation is reversed until operation becomes stabilized at maximum power conditions. The circuit includes a sampling means for periodically sampling the output power. The sampling means is connected to a comparison means providing an output signal, the condition of which is indicative of whether the power at any given sampling period is greater or less than the previous sampling period. Means are provided for detecting on a coincidence basis, the condition of the comparison means output signal and for altering the magnitude of the current or voltage of the power supply toward that which obtains maximum power.

Emergency standby system for automatic transfer from utility power to a battery powered system

Abstract: An emergency standby power system for automatic transfer from utility power to a battery powered inverter when a normal source of utility power is interrupted to a given load, and for automatic re-transfer to utility power when it is restored. The inverter includes SCR circuitry whereby commutation failure during start-up and shut-down is prevented by applying power to the inverter prior to the application of the gate drive during start-up, and removing power from the inverter prior to the removal of the gate drive during shut-down. Further, the control circuitry ensures that the first SCR gated on will operate for a complete one-half cycle, thereby fully charging the commutating capacitor for reliable commutation off of the first SCR before turning on the second SCR. The control circuitry also permits the inverter to start up even if it is presented with a short circuit and operate without damage.

Advancements in the design of solar-array to battery charge current regulators

Abstract: A spacecraft power system is described which uses a solar array as power source and a storage battery. Through the application of power electronics the system is optimized in two stages, the final version of which uses an analog maximum power tracker. The power maximization concept is developed and a circuit design is presented. The maximum power tracker circuit has been breadboarded, and some test results are included.

Dynamic stability and power system stabilizersߞAnalysis and tests on the Venezuelan system

Abstract: The nature of undamped oscillations in a power system is closely examined in this paper and an experimental approach is proposed for the adjustment of the power system stabilizers to damp these oscillations. A description is given of the poorly damped and occasionally sustained oscillations that the Venezuelan Interconnected power system experienced after the installation of high initial response solid-state exciters and a detailed discussion is presented of the results of tests performed on the power system with stabilizers adjusted using the experimental approach proposed.

Inverter control apparatus

Abstract: An apparatus for controlling the operation of an inverter which converts DC power obtained by rectification of a received AC power or DC power received from a battery which is alternatively actuated in case of an AC power supply failure or the like, into AC power. The inverter control apparatus includes a first control means which detects the output voltage of the inverter to thereby control the operation of the inverter in accordance with the detected value of the inverter output voltage. The inverter control apparatus further includes a detector for detecting variations in the input voltage of the inverter and second control means for controlling the width of the firing angle which is controlled by the first control means, in accordance with the detected value of the inverter input voltage variations, so that variations in the output voltage of the inverter may be suppressed even in the case of occurrence of variations in the input voltage of the inverter.

Electronic apparatus incorporating a power savings feature

Abstract: A power control system for electronic machines is capable of realizing substantial power savings. A logic circuit is activated by electric energy produced by a mechanical-electric power converter means with the push of a key without requiring a power source such as a battery. Other elements such as power on-off switch can be also eliminated.

Power processing module for military digital equipment power subsystem

Abstract: A 28V 75A DC-DC Converter has been developed as a Standard Primary Power Module for application in the U. S. Army Electronics Command digital equipment power systems. A new power stage concept, "Series Inductor/Parallel Inverter," was mechanized into a phase displed four power stage configuration that provides the necessary protection of the power transistors from overstress during transformer saturation, during overlap of the two switching transistors due to storage time, during startup and during output overload. The application of the dual loop control feedback system to this multi stage system provides precision regulation and good dynamic response for the DC output.

Solar array maximum power tracking with closed-loop control of a 30-centimeter ion thruster

Abstract: A new solar array/ion thruster system control concept has been developed and demonstrated. An ion thruster beam load is used to automatically and continuously operate an unregulated solar array at its maximum power point independent of variations in solar array voltage and current. Preliminary tests were run which verified that this method of control can be implemented with a few, physically small, signal level components dissipating less than two watts.

Solar photovoltaic power stations

Abstract: The subsystems of a solar photovoltaic central power system are identified and the cost of major components are estimated. The central power system, which would have a peak power capability in the range of 50 to 1000 MW, utilizes two types of subsystems - a power conditioner and a solar array. Despite differences in costs of inverters, the overall cost of the total power conditioning subsystem is about the same for all approaches considered. A combination of two inverters operating from balanced dc buses as a pair of 6-pulse groups is recommended. A number of different solar cell modules and tracking array structures were analyzed. It is concluded that when solar cell costs are high (greater than $500/kW), high concentration modules are more cost effective than those with low concentration. Vertical-axis tracking is the most effective of the studied tracking modes. For less expensive solar cells (less than $400/kW), fixed tilt collector/reflector modules are more cost effective than those which track.