Multi-node electrical network

• US 3,942,028 A
• Filed: 10/16/1974
• Issued: 03/02/1976
• Est. Priority Date: 10/16/1974
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Baker, Richard H.
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Ginsburg, M.
• Application Number:
  US05/515,284
• Time in Patent Office: 503 Days
• Field of Search: 323/23, 323/24, 323/25, 307/64, 307/65, 307/66, 307/252 T, 307/296
• US Class Current: 307/66
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems

Abstract

A multi-node network having two sets of SCRS, each set comprising a pair of parallel-connected, oppositely-polarized SCRs, the sets being electrically joined to form a common connection whereby electric current can flow through one pair to the common connection, thence to a load and/or to and through the other pair, or electric current can flow through said other pair to the load. Each SCR of the SCR pairs is triggered by transient signals such that the common connection can receive continuous power through either set of SCRs of the power and the connection can be switched between sources.

Claims

1. An electric system that comprises, in combination, a first source of a-c electric energy, a second source of a-c electric energy, means maintaining the first source and the second source in time phase, a load and a multinode network interconnection the first source, the second source and the load, said multi-node network comprising at least two sets of SCRs, each set comprising a pair of parallel-connected and oppositely polarized SCRs, said two sets being connected together to provide a common connection between the pairs to permit current to pass from the first source through one pair to the common connection and thence to the load, through said one pair to the common connection and thence through the other pair to the second source, and from said second source through said other pair to the common connection and thence to the load, as alternate, successive or simultaneous conditions of network operation.

2. A multi-node network as claimed in claim 1 that further include trigger-means connected to activate each SCR by a transient gate signal either concurrently with or slightly ahead of the onset of a time-varying forward bias voltage across the SCR.

3. A multi-node network as claimed in claim 1 that further includes trigger-means connected to activate each SCR of each set in a programmed fashion.

4. Apparatus as claimed in claim 3 in which said second source includes electric storage batteries and in which the trigger means in combination with the two sets, acts to permit electric energy to flow from the first source to the load as well as to the second source and, in the event of interruption of electric energy flow from the first source, to permit electric energy to flow from the second source of electric energy to the load.

5. Apparatus as claimed in claim 4 in which the trigger means acts in combination with connected sets to cause the second source of electric energy to power the load through the remaining part of the current cycle of the first source and to trigger the one set just prior to the beginning of the next cycle of current of the first source to permit said first source to feed electric energy to the load at the onset of said next cycle.

6. A multi-node network as claimed in claim 1 that further includes trigger-signal means connected to activate each SCR of each set in a predetermined manner such that each SCR of each set is activated by a transient gate signal concurrently with the onset of a time-varying forward bias voltage across the SCR or just slightly before set onset, thereby to cause an SCR, once it has ceased conducting, to conduct again only at the beginning of a new voltage cycle.

7. In an electrical system to energize a load, apparatus that comprises, in combination, a primary source of a-c electric energy, a secondary source of a-c electric energy, means maintaining the two sources substantially in time phase, and semiconductor means connected between the primary source and the secondary source and the load, said semiconductor means being connected in a series-parallel network combination such that the network forms a positive OR-gate in parallel with a negative OR-gate, corresponding parts of the two OR-gates being connected directly together, the semiconductor means being thyristors.

8. Electrical apparatus that comprises a load, a primary source of a-c power, a secondary source of a-c power, means maintaining the two sources substantially in time phase and semiconductor means interconnecting the two sources, said semiconductor means being connected in a series-parallel network combination such that the network forms a positive OR-gate in parallel with a negative OR-gate, corresponding parts of the two OR-gates being connected directly together and being network parts through which electric current can flow in either direction of flow and in a controllable fashion from the primary source to the secondary source and between the two sources and the load.

9. An electric system having in combination, a load, a primary source of electric energy to energize the load, a secondary source of electric energy to energize the load,

means maintaining the secondary source in time phase with the primary source, and a multi-node network connected between the sources and the load, that comprises a set of thyristors oppositely polarized and a set of rectifier means oppositely polarized, the two sets being connected together to provide a common connection therebetween to permit electric current to pass from the primary source of electric energy through one set to the common connection and thence to the load and from the secondary source of electric energy through said other set to the common connection and thence to the load, as alternate, successive or simultaneous conditions of network operations.

10. Apparatus as claimed in claim 9 in which the set of rectifier means comprises oppositely-polarized diodes.

11. Apparatus as claimed in claim 10 wherein the secondary source comprises a plurality of batteries interconnected to form a power unit which accepts electric energy in a charging mode and feeds the load in a discharging mode and wherein said means maintaining the secondary source in time phase comprises master control means that supervises interconnection of said batteries.