Power control apparatus and method and power generating system using them

• US 5,654,883 A
• Filed: 06/07/1994
• Issued: 08/05/1997
• Est. Priority Date: 06/11/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Takehara, Nobuyoshi, Kurokami, Seiji
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Riley, Shawn
• Application Number:
  US08/255,929
• Time in Patent Office: 1,155 Days
• Field of Search: 363/95, 363/80, 363/79, 323/906, 323/299
• US Class Current: 363/79
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

A power control system for obtaining the maximum electric power from a battery power source. The system functions to vary an output voltage of the battery power source to obtain (m) power values from at least (m) voltage signals from a voltage detector and at least (m) current signals from a current detector which were sampled at desired intervals. A function is used which approximates the relations between the (m) voltage values and (m) power values. A voltage is calculated at which a power is set to a maximum value from the function and the (m) voltage and power values. The power is set at such a voltage into an output power set value and the output power of the battery power source is controlled.

Claims

1. A power control apparatus comprising:

power converting means for converting electric power from a battery power source and supplying the converted electric power to a load;

output value detecting means for detecting an output value of said battery power source;

output value determining means for determining an output set value of said battery power source; and

control means for controlling said power converting means, such that the output value of said battery power source becomes the output set value of said output value determining means,

wherein said control means and said output value determining means control said power converting means, such that;

at a first step, the output set value of said output value determining means is a predetermined value and an operation voltage detected by said output value detecting means becomes the predetermined set value;

at a second step, said output value determining means determines m-voltage set values which are calculated by adding to or subtracting from the operation voltage of the first step a predetermined segmental quantity, and the operation voltage detected per each of the m-voltage set values detected by said output value detecting means becomes the voltage set value per each of m-values; and

at a third step, each of m-power values obtained based on m-current values measured correspondingly to each of the m-operation voltages at the second step, and each of the m-voltage values are introduced into a function formulated from a quadratic or cubic function of voltage and equations are derived therefrom to obtain a plurality of coefficients, further a differential function is derived from the function and the plurality of coefficients is introduced into the differential function to obtain a numerical value, and then the numerical value is used as the set value of said output value determining means, such that the operation voltage detected by said output value detecting means becomes the numerical value.

2. An apparatus according to claim 1, wherein said battery power source is a solar cell power source.

3. An apparatus according to claim 2, wherein said solar cell power source is used as the power source photovoltaic element having a non-monocrystalline semiconductor.

4. An apparatus according to claim 3, wherein said non-monocrystalline semiconductor is an amorphous silicon semiconductor.

5. An apparatus according to claim 3, wherein said solar cell battery power source is a power source mounted on a roof.