Showing papers on "Maximum power principle published in 1974"
Patent•
20 Dec 1974TL;DR: In this paper, the product of the current and battery voltage is recorded until the battery power reaches maximum at the maximum power point and the readings, peak power and the potential of the battery at the peak power, are held on meters by peak read and hold and track and hold circuits, respectively.
Abstract: A device for determining the state of charge in batteries. The battery un test is discharged to its maximum capability by controlling the discharge current in a linear manner. The product of the current and battery voltage is recorded until the battery power reaches maximum at the maximum power point. The readings, peak power and the potential of the battery at the peak power, are held on meters by peak read and hold and track and hold circuits, respectively. From the readings obtained the state of charge can be determined by using a calibration curve for the type of battery being tested.
125 citations
10 Jun 1974
TL;DR: In this paper, the difference between the measured thermal impedance of power transistors when determined by the pulsed heating curve and cooling curve techniques is discussed, and the theoretical predictions of the model are shown to be in good agreement for practical applications with three-dimensional computer simulations and experimental results.
Abstract: Differences between the measured thermal impedance of power transistors when determined by the pulsed heating curve and cooling curve techniques are discussed. These differences are shown to result primarily because the power density distributions of these devices change as the devices heat; as a result of these changes the heating curve and the cooling curve are not conjugate. It is shown that the cooling curve technique, when the cooling curve is initiated from the most non-uniform steady state thermal distribution, (maximum voltage, maximum power) will indicate a larger value for the thermal impedance than will the pulsed heating curve technique, even for pulses in excess of the d-c power level. A one dimensional model for power transistor cooling is described. The theoretical predictions of the model are shown to be in good agreement for practical applications with three-dimensional computer simulations and experimental results. Using this model, it is possible to estimate an average junction temperature and the area of power generation at steady state. Both T0-66 and TO-3 encased devices of mesa and planar structures were included in this study.
36 citations
TL;DR: In this paper, the problem of drawing maximum power from an n port by suitably terminating it with another passive n port is studied, and methods are derived for determining sets of passive impedance matrices which are "optimal" in the sense that they draw maximum energy from a given n port.
Abstract: The problem of drawing maximum power from an n port by suitably terminating it with another passive n port is studied. Methods are derived for determining sets of passive impedance matrices which are "optimal" in the sense that they draw maximum power from a given n port. It is shown that, in all nontrivial cases, if there exists any (passive or otherwise) optimum-load impedance matrix, then there exist, in fact, infinitely many passive optimum-load impedance matrices.
23 citations
Patent•
01 Mar 1974TL;DR: In this article, a method and system for generating and displaying in flight a signal representative of the maximum power available from an aircraft turbine engine is presented, which is used to calculate the power of the aircraft turbine.
Abstract: A method and system for generating and displaying in flight a signal representative of the maximum power available from an aircraft turbine engine. Compressor inlet temperature and pressure, and output shaft speed are measured engine parameters employed to generate the desired signal.
10 citations
TL;DR: In this paper, a power-combining scheme was proposed for IMPATT diode amplifiers that use several packaged diodes in parallel in a coaxial housing and achieved a power output of 8 W (input locking power equals 300 mW) at 4 GHz without exceeding safe operating temperatures.
Abstract: IMPATT diode amplifiers are described that use several packaged diodes in parallel in a coaxial housing. With a pair of GaAs Schottky-barrier diodes, a power output of 8 W (input locking power equals 300 mW) was obtained at 4 GHz without exceeding safe operating temperatures. Similarly, three-diode circuits produced 15 W (locking power equals 3.5 W) at 4 GHz and >10 W (locking power equals 2.7 W) at 6 GHz under safe operating conditions. The maximum power obtained from the pair was 11 W. The maximum power obtained from the 4 GHz three-diode circuit was 21 W. The efficiency of the diodes at the maximum power level was 12-13 percent. The characteristics of the pair are compared with those of the individual diodes and it is concluded that this power-combining scheme is very efficient and should be economically advantageous. The scheme permits the total diode area utilized in a single cavity to be increased significantly beyond that which is practical in a single diode package. The use of parallel operation permits efficient heat sinking of each diode package, which is impractical with series operation. The technique employed has been shown to be suitable for extension to three or more diodes for higher power. It is required that each set of diodes be matched for similar I-V characteristics. With this constraint, the close RF coupling of the diodes in conjunction with appropriate stabilizing resistor(s) assures that the diodes operate cooperatively as a unit capable of being powered from a single current-regulated source.
2 citations