Power supply system provided with photovoltaic generator

• US 6,528,977 B2
• Filed: 11/29/2001
• Issued: 03/04/2003
• Est. Priority Date: 11/29/2000
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Arakawa, Shinichi
• Primary Examiner(s): Vu, Bao Q.
• Application Number:
  US09/995,672
• Publication Number:
  US 20020063552A1
• Time in Patent Office: 460 Days
• Field of Search: 323/906, 323/282, 323/284, 363/124
• US Class Current: 323/282
• 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 supply system includes a photovoltaic generator, a load to which electric power is supplied from the photovoltaic generator, an electrical system for receiving a portion of the electric power generated by the photovoltaic generator and supplying electric power to the load, and a control unit for controlling the reception and the supply of the electrical power by the electrical system. To ensure that the photovoltaic generator generates electric power at an optimal operational point, the control unit is adapted to not operate when the maximum electric power P_max generated by the photovoltaic generator and an electric power P_L consumed in the load are equal to each other, and to be operated when P_max>P_L, thereby permitting the electrical system to receive a surplus electric power ΔP1, and to be operated when P_max<P_L, thereby supplying a deficient electric power ΔP₂ from the electrical system to the load.

Claims

1. A power supply system comprising:

a first photovoltaic generator for generating power;

a second photovoltaic generator for generating power;

a constant-power load for receiving the power generated from the first photovoltaic generator;

a power consumption source of a predetermined current-voltage characteristic for receiving the power generated by the second photovoltaic generator; and

a control system that operates to control supply of the power to the load and to the power consumption source;

wherein the operation of the control system is a function of the maximum electric power (P_max) generated by the first photovoltaic generator and the electric power (P_L) consumed in the load;

such that

when the maximum electric power (P_max) generated by the first photovoltaic generator is equal to the electric power (P_L) consumed by the load (P_max=P_L), said control system does not operate; and

when the maximum electric power (P_max) generated by the first photovoltaic generator is greater than the electric power (P_L) consumed by the load (P_max>

P_L), said control system operates to permit the power consumption source to receive a surplus of electric power (Δ

P₁=P_max−

P_L) from the first photovoltaic generator; and

when the maximum electric power (P_max) generated by the first photovoltaic generator is less than the electric power (P_L) consumed by the load (P_max<

P_L), said control system operates to supply the deficient electric power (Δ

P₂=P_L−

P_max) from the second photovoltaic generator to the load.

2. The power supply system according to claim 1 wherein the first photovoltaic generator is of a high-voltage and low-current type and the second photovoltaic generator is of a low-voltage and high-current type.

3. The power supply system according to claim 2 further comprising a DC/DC converter which converts the electric power generated by the first photovoltaic generator into a constant-voltage power and supplies the converted power to the load.

4. The power supply system according to claim 3 wherein the control system includes a bidirectional converter provided between the first and second photovoltaic generators and a power management ECU for determining the magnitude and polarity of the electric power flow through the bidirectional converter, based on the electric power generated by the first photovoltaic generator.

5. The power supply system according to claim 4 wherein the power consumption source is a water electrolyzer and the load is an auxiliary equipment of the water electrolyzer, wherein an operating voltage for the auxiliary equipment is higher than that for the water electrolyzer.

6. The power supply system according to claim 5 wherein the auxiliary equipment comprises an inverter and a water pump.

7. The power supply system according to claim 4 wherein the power consumption source is an accumulator.

8. The power supply system according to claim 1 wherein the control system includes a bidirectional converter provided between the first and second photovoltaic generators and a power management ECU for determining the magnitude and polarity of the electric power flow through the bidirectional converter, based on the electric power generated by the first photovoltaic generator.

9. The power supply system according to claim 8 wherein the power consumption source is a water electrolyzer and the load is an auxiliary equipment of the water electrolyzer, wherein an operating voltage for the auxiliary equipment is higher than that for the water electrolyzer.

10. The power supply system according to claim 2 wherein the control system includes a bidirectional converter provided between the first and second photovoltaic generators and a power management ECU for determining the magnitude and polarity of the electric power flow through the bidirectional converter, based on the electric power generated by the first photovoltaic generator.

11. The power supply system according to claim 10 wherein the power consumption source is a water electrolyzer and the load is an auxiliary equipment of the water electrolyzer, wherein an operating voltage for the auxiliary equipment is higher than that for the water electrolyzer.

12. The power supply system according to claim 1 further comprising a DC/DC converter which converts the electric power generated by the first photovoltaic generator into a constant-voltage power and supplies the converted power to the load.

13. The power supply system according to claim 12 wherein the control system includes a bidirectional converter provided between the first and second photovoltaic generators and a power management ECU for determining the magnitude and polarity of the electric power flow through the bidirectional converter, based on the electric power generated by the first photovoltaic generator.

14. The power supply system according to claim 13 wherein the power consumption source is a water electrolyzer and the load is an auxiliary equipment of the water electrolyzer, wherein an operating voltage for the auxiliary equipment is higher than that for the water electrolyzer.

15. The power supply system according to any one of claims 1 to 14 further comprising a PPT (Peak Power Tracker) provided between the second photovoltaic generator and the power consumption source.

16. A power supply system comprising:

a first system section including a first photovoltaic generator for generating power and a constant-power load for receiving the power generated from the first photovoltaic generator;

a second system section including a second photovoltaic generator for generating power and a power consumption source of a predetermined current-voltage characteristic for receiving the power generated by the second photovoltaic generator; and

a control system that operates to control supply of the power to the load and to the power consumption source;

wherein the operation of the control system is a function of the maximum electric power (P_max) generated by the first photovoltaic generator and the electric power (P_L) consumed in the load;

such that

when the maximum electric power (P_max) generated by the first photovoltaic generator is equal to the electric power (P_L) consumed by the load (P_max=P_L), said control system does not operate; and

when the maximum electric power (P_max) generated by the first photovoltaic generator is greater than the electric power (P_L) consumed by the load (P_max>

P_L), said control system operates to permit the power consumption source to receive a surplus of electric power (Δ

P₁=P_max−

P_L) from the first photovoltaic generator; and

when the maximum electric power (P_max) generated by the first photovoltaic generator is less than the electric power (P_L) consumed by the load (P_max<

P_L), said control system operates to supply the deficient electric power (Δ

P₂=P_L−

P_max) from the second photovoltaic generator to the load.

17. The power supply system according to claim 16 wherein the first photovoltaic generator is of a high-voltage and low-current type and the second photovoltaic generator is of a low-voltage and high-current type.

18. The power supply system according to claim 17 further comprising a DC/DC converter which converts the electric power generated by the first photovoltaic generator into a constant-voltage power and supplies the converted power to the load.

19. The power supply system according to claim 18 wherein the control system includes a bidirectional converter provided between the first and second system sections and a power management ECU for determining the magnitude and polarity of the electric power flow through the bidirectional converter, based on the electric power generated by the first photovoltaic generator.

20. The power supply system according to claim 19 wherein the power consumption source is a water electrolyzer and the load is an auxiliary equipment of the water electrolyzer, wherein an operating voltage for the auxiliary equipment is higher than that for the water electrolyzer.