US 5,493,204 A · Negative impedance peak power tracker

Abstract

A peak power tracker apparatus is used for controlling the negative impedance of converter for transferring maximum power from a solar array source to a battery and load typically used in space vehicles, by capacitive differentiation sensing the solar array source voltage for sensing the peak power point at which the source voltage first begins to become unstable and collapses, and then providing a step down control signal which controls a current mode pulse width modulator to control the converter to vary the negative impedance into the solar array then reserving back to a stable point at which the tracker then provide a linear ramp signal to the modulator to control the converter to drive the source voltage again to the peak power point, so as to alternate the feedback loop and source voltage between a stable point and the peak power point so as to transfer maximum power while preventing the source voltage to pass through an unstable point for discontinuous but stable operation at peak power transfer which is independent of array performance and is adaptable to a wide range of power sources.

Claims11

Dependent claims

A peak power tracker apparatus for maintaining peak power delivered from a source having an input impedance and source voltage and providing electrical power to a load, said apparatus comprising,

converter means connected between said source and said load for providing said source with a negative load impedance which is controllable, said source voltage becomes unstable when said input impedance equals said load impedance when said source delivers peak power through said converter to said load at a peak power point,
peak power tracking means connected to said source for sensing said source voltage, and for providing a first signal when said source is stable before becoming unstable, and for providing a second signal when said source voltage begins to become unstable when said source delivers peak power to said load at said peak power point, and
control means connected to said peak power tracking means for receiving said first and second signals and connected to said converter for controlling said converter to vary said load impedance, said control means for receiving said first signal when controlling said converter means to vary said input impedance to drive said source voltage from a stable point towards said peak power point and for receiving said second signal said when controlling said converter means to vary said input impedance to drive said source voltage away from said peak power point to said stable point.

A method for maintaining peak power delivered from a source to a load, said source has a source voltage, an input impedance and a load impedance which is negative, said source voltage begins to become unstable at a peak power point of maximum power transfer from said source to said load when said input impedance equals said load impedance, said method comprising the steps of,

transferring power from said source to said load,
sensing when said source voltage is between said peak power point and a stable point,
generating a first control signal indicating that said source voltage is stable between said peak power point and said stable point,
controlling said input impedance during the present of said first control signal to drive said source voltage towards said peak power point,
sensing when said source voltage is at said peak power point,
generating a second unstable control signal indicating when said source voltage is at said peak power point, and
controlling said load impedance during the present of said second control signal to drive said source voltage from said peak power point to said stable point.

4 more elements

Dependencies are inferred from the claim text.

Negative impedance peak power tracker

Life of this patent

Negative impedance peak power tracker

Life of this patent

Abstract

Claims11