AC/DC hybrid power system

• US 20040095091A1
• Filed: 11/06/2003
• Published: 05/20/2004
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: WorldWater & Solar Technologies Inc.
• Original Assignee: WorldWater & Power Corp. (Entech Solar, Inc.)
• Inventors: McNulty, Thomas C., Rangarajan, Anand
• Granted Patent: US 7,145,265 B2
• Time in Patent Office: Days
• US Class Current: 320/101
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: Y02B 10/70 Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies

Abstract

A hybrid power system has two voltage sources, a variable DC power source, and a second power source, connected through selection components to a common node. The variable DC power source may be a solar power source and the second source may be an AC grid. The selection components, e.g. blocking diodes, SCRs, or relays, allow one or both of the sources to be connected to the node depending on the voltages produced by the sources. A variable speed drive and load may be connected to the node.

Claims

1. A hybrid power system, comprising:

a variable DC power source;

a second power source;

first and second selection components connected respectively to the outputs of the variable DC power source and second power source and having their outputs connected to a common node;

Wherein, the first and second selection components select either or both power sources to apply power to the common node depending on the magnitude of the voltage from each source.

2. The system if claim 1 wherein the variable DC power source is a solar power source.

3. The system of claim 1 wherein the second power source is an AC power grid.

4. The system of claim 3 wherein the AC voltage from the power grid is rectified.

5. The system of claim 1 wherein the second power source is a battery.

6. The system of claim 1 wherein the second power source is a 3-phase AC source having three windings and the second selection components has three elements, one connected to each winding.

7. The system of claim 1 wherein the first and second selection components are blocking diodes.

8. The system of claim 1 wherein the first and second selection elements are silicon controlled rectifiers (SCRs).

9. The system of claim 1 wherein the first and second selection elements are relays.

10. The system of claim 1 further Comprising a variable speed drive having its input connected to the common node.

11. The system of claim 10 further comprising a load connected to the output of the variable speed drive.

12. The system of claim 1 wherein the variable DC power source is a photovoltaic panel and the load is a motor.