MAXIMUM POWER POINT TRACKER

• US 3,566,143 A
• Filed: 03/11/1969
• Issued: 02/23/1971
• Est. Priority Date: 03/11/1969
• Status: Expired due to Term

• Current Assignee: Arnold S. Cherdak, James L. Douglas
• Original Assignee: Arnold S. Cherdak, James L. Douglas
• Inventors: Cherdak, Arnold S., Douglas, James L.
• Application Number:
  US04/806,226
• Time in Patent Office: 714 Days
• US Class Current: 307/126
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

Apparatus for detecting the instantaneous power from a power source and operatively selectively disconnecting the power source from a load and a battery recharging circuit upon generation of a pulse from a power peak detector or a peak absence detector, power to the load being supplied by the battery when the power source is disconnected, battery overcharged protection controls further operating to override reset of the power switch, the power source being forced to supply a range of output voltage corresponding to that providing maximum power output of the source.

Claims

1. A maximum power point tracker for adaptation to control the operation of a power source, including:

a voltage sensor and a current sensor operatively coupled to the power source, an instantaneous power detector connected to the current sensor and voltage sensor, a peak detector connected to the current sensor and voltage sensor, a peak detector connected to the power detector for detecting a peak value in the instantaneous power from the power source, an OR gate operatively coupled to the peak detector, a pulse absence detector connected between said peak detector and said OR gate, a bistable flip-flop connected to said OR gate, a power switch driver connected to the flip-flop, a power switch connecting said power source to a load, said flipflop being actuated in one stable state to activate the power switch driver to close the power switch thereby connecting the power source to the load, said flip-flop being operable in another stable state to activate the power source driver and open the power switch, thereby disconnecting the power source from the load, whereby the power source is caused to supply said load with a range of voltages corresponding to that at which the maXimum power output of the source occurs.

2. The structure of claim 1 wherein said instantaneous power detector comprises:

a first magnetic core and a second magnetic core, first windings magnetically coupled to said first core and connected to said power source, second windings magnetically coupled to said second core and to said power source, a closed loop field excitation circuit magnetically coupled to said first and said second core, said excitation circuit including a waveform generator, magnetic field sense windings magnetically coupled to said first and said second core, a sense amplifier connected to said sense windings, a reset circuit and a bistable flip-flop connected to receive a signal from the sense amplifier, and OR gate operatively coupled to said reset switch and said flip-flop, said waveform generator being connected to receive a signal from said reset switch, a resistor and a capacitor connected to said first and second windings, a reset switch connected in parallel with said capacitor, and a voltage detector connected in parallel with said capacitor.

3. The structure of claim 2, wherein said waveform generator includes a sawtooth generator the waveform of which comprises negative and positive components.

4. The structure of claim 2, wherein said waveform generator supplies a self-oscillating signal to said flip-flop.

5. The structure of claim 2, and further including means coacting with said instantaneous power detector for average power detection comprising:

third and fourth magnetic cores, third and fourth windings magnetically coupled to said third and fourth cores and said power source, a second closed loop excitation circuit magnetically coupled to said third and fourth cores, a second waveform generator in said second excitation circuit, second field sense windings magnetically coupled to said third and fourth cores, a second sense amplifier connected to said second sense windings, a second reset circuit and a second bistable flip-flop connected to said second sense amplifier, a second OR gate connected to said second reset switch and said second flip-flop, said second reset switch supplying a reset signal to said second waveform generator, a second resistor and a second capacitor connected to said third and fourth windings, and a second reset switch connected in parallel with said second capacitor, said voltage detector being connected in parallel with said second capacitor.

6. The structure of claim 5, wherein said second waveform generator includes a sawtooth generator the waveform of which includes negative and positive components.

7. The structure of claim 5, wherein said waveform generator supplies a self-oscillating signal to said flip-flop.

8. The structure of claim 1, and further including override control means operatively connected to said power switch driver for preventing the closing thereof.

9. The structure of claim 8, wherein said control means includes detectors for sensing excessive temperature, current and voltages of at least a portion of said load, and AND gate connected between said flip-flop and said power switch driver, said detectors normally supplying a '"'"''"'"''"'"''"'"'positive'"'"''"'"''"'"''"'"' signal to said AND gate, said positive signal being extinguished in response to excessive load temperature or current voltage to shut down said AND gate.

10. The structure of claim 8, wherein said control means includes detection of current imbalance among a plurality of connected battery systems and function to promote balance among battery currents.