Showing papers on "Maximum power principle published in 1986"

Electronic control circuit

Abstract: An electronic control circuit for use with a varying power supply (21) such as the output from a solar collector or wind generator and a load (22) such as a battery being charged by the power supply, provides two forms of control for maximizing power transfer. Firstly, an inverter (20) with varying duty cycle is connected between supply and load and the circuit controls the duty cycle thereof to maximize power transfer and secondly a stepper motor (25) is connected to the supply to physically alter the power provided by the supply by, in the case of a solar collector for example, altering the angle of the collector relative to the sun. The cirucit compares successive measurements of the output power and generates control signals to alter the angle of the collector and modify the duty cycle. The circuit is adapted to calculate the mean maximum power position. Limit detection is included to prevent latch-up and a voltage regulator is included to override the system.

Helicopter power available to hover indicator

Abstract: The power required for a helicopter to hover is generated (14, 82) as the ratio of current operating power in forward flight (12, 77) determined (10, 73) from data relating operating power in forward flight to power required for hover for the aircraft. The power required to hover is compared (18, 83) with the maximum power available developed (16, FIG. 2; FIG. 3) by an engine model algorithm utilizing actual engine parameters. The comparison of maximum power to power required for hover is utilized to provide an indication (22) to the pilot. The viability of the indication is indicated by a "ready" indication (26).

Comments on “considerations on the reactive power in nonsinusoidal situations”

Abstract: The LC compensator proposed by L.S. Czarnecki (1986) is asserted to have a maximum power factor, but costs more than pure capacitance compensators. However, an optimum power factor with respect to L and C may not exist, but an optimum for a given compensator cost does, and it may be less expensive than a pure capacitance compensator rendering the same power factor.

Photovoltaic-electrolyzer system transient simulation results

Abstract: Brookhaven National Laboratory has developed a Hydrogen Technology Evaluation Center to illustrate advanced hydrogen technology. The first phase of this effort investigated the use of solar energy to produce hydrogen from water via photovoltaic-powered electrolysis. A coordinated program of system testing, computer simulation, and economic analysis has been adopted to characterize and optimize the photovoltaic-electrolyzer system. This paper presents the initial transient simulation results. Innovative features of the modeling include the use of real weather data, detailed hourly modeling of thermal characteristics of the PV array and of system control strategies, and examination of systems over a wide range of power and voltage ratings. The transient simulation system TRNSYS was used, incorporating existing, modified or new component subroutines as required. For directly coupled systems, the authors found the PV array voltage which maximizes hydrogen production to be quite near the nominal electrolyzer voltage for a wide range of PV array powers. The array voltage which maximizes excess electricity production is slightly higher. The use of an ideal (100 percent efficient) maximum power tracking system provides only a six percent increase in annual hydrogen production. An examination of the effect of the PV array tilt indicates, as expected, that annual hydrogenmore » production is insensitive to tilt angle within +-20 deg of latitude. Summer production greatly exceeds winter generation. Tilting the array, even to 90 deg, produces no significant increase in winter hydrogen production.« less

Control method of solar power generator

Abstract: PURPOSE:To attain the automatic control of a solar battery to the maximum power point regardless of the characteristics of the solar battery, by detecting the voltage and the current of a solar battery and setting the reference voltage value to obtain the maximum power point of the solar battery together with monitor given to the variations of both the electric power and the voltage. CONSTITUTION:The maximum power point M is set when the luminous intensity and the temperature are constant, and a point N shows the voltage value of a solar battery. In an early tracking stage for the maximum power point, the reference voltage value VPV* is set so as to equal to the no-load voltage V0 shown in the figure. Then the VPV* is reduced in a fixed with in a prescribed sampling period, and the electric power increases toward A and then moves toward C after exceeding the point M. Then the VPV* is delivered in the direction where it is increased in the fixed width after detecting that the electric power is set toward C. The electric power reaches the direction B when the VPV* is continuously increased. Then the VPV* is reduced again after detecting that the electric power shifted toward B. When these actions are repeated, the VPV* has the reciprocating shifts at a place near the point M.

Control method for sunbeam power generator

Abstract: PURPOSE:To always track automatically the maximum power point and to attain the effective use of energy by detecting the voltage and the current of a solar battery and securing the current reference value serving as the maximum power point of the solar battery while monitoring the changes of the power and the voltage or the power and the current. CONSTITUTION:The current reference value IPV is set at 0 in the early stages of tracking and then increased by a fixed amount for a prescribed sampling period. Meanwhile, the electric power is increased in the direction A and the shifted to the direction C after a point M. This shift in the direction C is decided by detecting that both the power and voltage are reduced. Then the current IPV is delivered in the direction where it is reduced by a fixed amount. Then the power is shifted up to the direction B through the direction D. Here the current IPV is reduced again after detecting the shift of the power in the direction B. This shift of the power in the direction B is decided by detecting that the power is reduced and the voltage is increased. The above-mentioned actions are repeated sot that the current IPV reaches a point near the maximum power point M and parts from that point.

Article conveying system

Abstract: PURPOSE:To efficiently move conveying vehicles simultaneously by controlling to distribute the maximum supply power from a power source to be supplied to the movements of the vehicles within the power source capacity. CONSTITUTION:A controller 101 of a power source supply instructing unit 100 outputs a power control command to a power distribution controller 400 on the basis of information from a carrier information memory 103 for storing the state signal of a carrier from sensors S1-S3 provided in a conveying path R and information from a command analysis execution unit 102 for translating the information relative to a moving command input from a terminal unit 200. A power distribution controller 400 supplies power to a stator on the path R by a peak value controller 402 for controlling to distribute the peak power within the range of the maximum supply power and a time division controller 403 for controlling to distribute the maximum power supply power in a time division manner.

Photovoltaic power-generating set

Abstract: PURPOSE:To always operate a photovoltaic power-generating section at the maximum power, by providing a maximum power controlling means which gives three stages, large, middle, and small, of phase commands to an inverter and discriminates the scale of the power by detecting the power corresponding to each phase command, and then, gives the phase command for generating the maximum power to the inverter. CONSTITUTION:The photovoltaic power-generating set of this invention is composed of an optical power-generating element, reverse blocking diode 2, reactor 3, capacitor 4, inverter circuit 5, voltage reference setter, voltage controlling circuit 8, and phase controlling circuit 9. An AC current transformer 10 and AC voltage transformer 11 are connected with the load side of the inverter circuit 5 and the effective power of the output of the inverter circuit 5 is detected by means of a power detector 12. The effective power is supplied to a power comparator circuit 13 and the voltage controlling circuit 8 and phase controlling circuit 9 are driven by using the compared output of the circuit 13, and thus, the phase of the inverter is controlled.

Pressure oil feeder

Abstract: PURPOSE:To make the maximum power of a hydraulic actuator alterable as well as to reduce the cost of production, by installing a pressure controlling member, controlling the maximum hydraulic power according to the operating valve operated, in a discharge passage of a pump. CONSTITUTION:A solenoid proportional type pressure control valve 40 is installed in a discharge passage 21 of a hydraulic pump 20, and the maximum hydraulic power of this discharge passage 21 is made so as to be controllable for increase or decrease by a current value to be fed to the solenoid 41, while an electric current is fed to this solenoid 41 from a control box 31 together with exciting and demagnetizing signals for each of solenoids 22a, 22b-26a, 26b. With this constitution, when discharged pressure oil of one pump 20 is fed to plural hydraulic actuators, the maximum hydraulic power of respective hydraulic actuators are alterable with one pressure control member, so that the maximum power of each hydraulic actuator is alterable as well as manufacturing cost is reducible, besides simplification in structure.

Computer-Aided Modeling and Analysis of Power Processing Systems (CAMAPPS), phase 1

Abstract: The large-signal behaviors of a regulator depend largely on the type of power circuit topology and control. Thus, for maximum flexibility, it is best to develop models for each functional block a independent modules. A regulator can then be configured by collecting appropriate pre-defined modules for each functional block. In order to complete the component model generation for a comprehensive spacecraft power system, the following modules were developed: solar array switching unit and control; shunt regulators; and battery discharger. The capability of each module is demonstrated using a simplified Direct Energy Transfer (DET) system. Large-signal behaviors of solar array power systems were analyzed. Stability of the solar array system operating points with a nonlinear load is analyzed. The state-plane analysis illustrates trajectories of the system operating point under various conditions. Stability and transient responses of the system operating near the solar array's maximum power point are also analyzed. The solar array system mode of operation is described using the DET spacecraft power system. The DET system is simulated for various operating conditions. Transfer of the software program CAMAPPS (Computer Aided Modeling and Analysis of Power Processing Systems) to NASA/GSFC (Goddard Space Flight Center) was accomplished.

Efficiency of producing additional power in units of nuclear power stations containing water-cooled-water-moderated reactors

Abstract: There is a basic possibility to raise the maximum power of a unit containing the VVER-1000 reactor in the course of the fuel charge burn-up and with lowering the coefficient of the energy-release nonuniformity in the reactor core. It is more advantageous economically to obtain additional power in carrying the peak load. With the duration of such operating conditions for 1000–2000 h/yr savings can amounts to 1–4 million rubles per year per 100 MW of additional power when compared to peaking GTP.

New method for maximum power consideration in lossy solar cells

Abstract: A mathematical model is presented for the current-voltage characteristic of the solar cell. Using this model closed-form expressions are obtained for the coordinates of the maximum-power point.

Device for the evaluation metering of power, particularly for the application of multiple tariffs in the consumption of electrical power

Abstract: The device for the evaluation metering of power is intended to measure the maximum power demand or to meter at least one power supplied over at least one period when given tariffs apply, using a single-phase or polyphase measurement and processing the current demanded. The device comprises at least one meter or one power controller with ammeter and is characterised in that the meter or controller incorporates the following: a power circuit containing as many single-phase current transformers 2, 102 as there are phases and as many single-phase rectifier bridges 4, 104 as there are phases; a filtering and adding device 5, 105; a thermal ammeter 6, 106; a device 7 for indicating when the current exceeds a threshold and for measuring the time during which this threshold is exceeded; and a device for controlling the operation of the controller 3, 120 connected in the power circuit.

A simple circuit for the evaluation of solar cells

Abstract: Describes a circuit to measure directly the maximum power output (Pmax) from a solar cell and also the voltage at which the maximum power is obtained. In addition, the circuit can be used for plotting the I-V curve of the solar cell on an X-Y recorder.

Optimal External Source Distribution in Subcritical Slab Reactors

Abstract: The problem of the optimal external source distribution for maximum power in sub-critical uniform slab reactors with a maximum flux constraint is analyzed. The complete analytical solution of the problem is obtained, within the one group diffusion approximation, using optimal control theory. Some numerical examples are included to illustrate the behavior of the optimal solution.