Parallel supply for multiple loads from a single power supply

• US 5,128,602 A
• Filed: 04/26/1991
• Issued: 07/07/1992
• Est. Priority Date: 04/26/1991
• Status: Expired due to Term

• Current Assignee: Delaware Capital Formation Incorporated (Dover Corporation), Dover Technologies International Inc. (Dover Corporation), European Aeronautic Defence and Space Company EADS NV
• Original Assignee: Metcal Incorporated (Dover Corporation)
• Inventors: Carter, Philip S. Jr.
• Primary Examiner(s): Wong, Peter S.
• Application Number:
  US07/691,854
• Time in Patent Office: 438 Days
• Field of Search: 323/267, 363/65, 333/1, 333/12, 333/35, 333/100, 333/109, 333/112, 333/113, 333/136, 333/137, 307/11, 307/31, 307/32, 307/33
• US Class Current: 323/267
• CPC Class Codes: G05F 1/577 for plural loads
• CPC Class Codes: H01P 5/12 Coupling devices having more than two ports H01P5/04 takes precedence
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence

Abstract

A single constant voltage power supply concurrently supplies a plurality of independent loads each with an independently selectable constant current load without interaction between the loads (currents) by employing a plurality of parallel connected circuits of electrical lengths equal to (2n-1)90° each connected between the constant voltage source and a different one of said loads.

Claims

1. A power supply for concurrently supplying a plurality of independent loads having impedance each with an independent selectable constant current without interaction between the loads comprising

a constant voltage power supply having an output port connected to

a plurality of two port networks each one of which fulfills the conditions Y₂₂ =0 and Y₂₁ ≠

0 where Y₂₂ and Y₂₁ are the equivalent short circuit admittance parameters of each network considered independently of the remaining networks, a first port of each network being connected to the output port of the power supply in parallel with the remaining networks, a second port of each network being connected to a separate and independent electrical load.

2. A power supply according to claim 1 wherein each network is a uniform transmission line, uniform cable, or uniform waveguide which has an electrical length equal to an odd number of one quarter wavelengths, where the characteristic impedances of each of the quarter wavelength transmission lines are the same.

3. A power supply according to claim 1 wherein the equivalent short circuit parameters of the network are represented by the symbol Y_mn, n and m being positive integers that refer to the various ports of the overall distribution network and all of Y_mn being equal to zero with the exception of those parameters for which both m and n are both greater than 1 where n=1 refers to the port at which the networks are connected in parallel and to which the power supply is also connected.

6. A power supply according to claim 1 wherein one or more of each network of the plurality of networks incorporates an ideal transformer.

7. A power supply according to claim 3 wherein Y₁₁ is also equal to zero.

8. A power supply according to claim 1 in which each of the two port networks fulfills the condition Y₁₁ =0 in addition to the conditions Y₂₂ =0 and Y₂₁ ≠

0, Y₁₁ being a short circuit admittance parameter of one of the networks.

9. A power supply according to claim 1 in which one or more of the plurality of networks consists of a length of low loss transmission line cable or waveguide and a low loss capacitance in parallel at the center of the transmission line, cable or waveguide.

10. A power supply according to claim 1 in which one or more of the plurality of networks consists of a series inductance L₀ connected to the power generator output plus a parallel capacitance C₀ connected in parallel across the load impedance, for which the condition √

L₀ C₀ =1/2π

f_o is fulfilled where f_o is the operating frequency of the power supply.

11. A power supply according to claim 1 in which one or more of the plurality of networks consists of a series capacitor C₀ connected to the power supply and a parallel inductance L₀ connected in parallel with the impedance of the load for which the condition √

L₀ C₀ =1/2π

f₀ is fulfilled where f₀ is the operating frequency of the power supply.

12. A power supply according to claim 1 wherein the equivalent short circuit parameters of the networks are represented by the symbol Y_mn, m and n being positive integers that refer to the various ports of the overall distribution network, all of the Y_mn being equal to zero except for the case where m≠

1 and n=1 and where m=1 and n≠

1.

4. A power supply for concurrently supplying a plurality of independent loads each with an independently selectable constant current load without interaction between the loads comprising an output circuit having an output connection with a constant voltage developed across said connection

a plurality of low loss circuits each having an electrical length of (2n-1)90°

where n is any one of various even integers

each said low loss circuit having its input connection connected to said output connection of said power supply.

5. A power supply according to claim 4 wherein

each said low loss circuit is a two port network, and wherein said low loss circuits have a sufficiently low loss that a short circuit across an output port does not effect the current supplied to the output port of any other of said low loss circuits.