Bidirectional load and source cycler

• US 5,751,150 A
• Filed: 08/11/1995
• Issued: 05/12/1998
• Est. Priority Date: 08/11/1995
• Status: Expired due to Term

• Current Assignee: Webasto Charging Systems, Inc. (Webasto Beteiligungs Verwaltung Gbr)
• Original Assignee: Aerovironment
• Inventors: Rippel, Wally E., Buchanan, Darrell
• Primary Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US08/513,689
• Time in Patent Office: 1,005 Days
• Field of Search: 324/537, 324/771, 324/772, 324/426, 363/37, 363/65, 363/72
• US Class Current: 324/537
• CPC Class Codes: B60R 16/03 for supply of electrical power to vehicle subsystems or for circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/2841 Signal generators
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: G01R 31/386 using test-loads
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 3/285 Single converters with a plurality of output stages connected in parallel parallel operation of a plurality of converters in dc distribution networks H02J1/10

Abstract

A system and method for cycling loads and sources can be connected to one or more loads and sources to controllably supply or absorb current with respect thereto. For example, DC voltages can be controllably supplied to each load from a DC bus using a plurality of DC-DC converters. Various DC converter configurations are available including independent, parallel and differential, to expand the types of simulations which can be performed on the load(s).

Claims

1. A system for sourcing and sinking electrical power comprising:

a poly-phase utility port for connecting the system with an electrical utility;

a device connected to the poly-phase utility port for interfacing the poly-phase utility port with a DC bus to provide a first DC voltage level thereon;

at least one bi-directional DC-to-DC converter for converting the first DC voltage level to at least one second DC voltage level; and

a controller for coordinating operation of the at least one bidirectional DC to DC converter.

2. The apparatus of claim 1, wherein the controller coordinates operation of the at least one bidirectional DC-to-DC converter to reduce current harmonics.

3. The apparatus of claim 2, wherein the controller reduces current harmonics by controlling a phase relationship between duty cycles of the at least one bidirectional DC-to-DC converter.

4. The apparatus of claim 1, wherein the controller coordinates operation of the at least one bidirectional DC-to-DC converter such that at least one pair of the at least one bidirectional DC-to-DC converter operates in parallel.

5. The apparatus of claim 4, wherein the controller operates switches associated with a first of the at least one bidirectional DC-to-DC converter according to a first duty cycle and operates switches associated with a second of the at least one bidirectional DC-to-DC converter according to a second duty cycle, and wherein the first and second duty cycles are out of phase with respect to one another.

6. The apparatus of claim 5, wherein the first and second duty cycles are 180 degrees out of phase.

7. The apparatus of claim 1, wherein the controller operates switches associated with a first of the at least one bidirectional DC-to-DC converter according to a first duty cycle and operates switches associated with a second of the at least one bidirectional DC-to-DC converters according to a second duty cycle, and wherein the first and second duty cycles are phased with respect to one another based upon a polarity of current through the first and second DC-to-DC converters.

8. The apparatus of claim 1, wherein the controller coordinates operation of the at least one bidirectional DC-to-DC converter such that at least one pair of the at least one bidirectional DC-to-DC converter operates differentially.

9. The apparatus of claim 8, wherein the controller operates switches associated with a first of the at least one bidirectional DC-to-DC converter according to a first duty cycle and operates switches associated with a second of the at least one bidirectional DC-to-DC converter according to a second duty cycle, and wherein the first and second duty cycles are in phase with respect to one another.

10. The system of claim 1, wherein said at least one bidirectional DC-to-DC converter further comprises:

first and second switches;

an inductor connected in parallel between said first and second switches; and

a capacitor for isolating ripple currents generated by said at least one bidirectional DC-to-DC converter.

11. A system for testing at least one electrical device comprising:

a DC bus driven at a DC voltage;

a pair of bidirectional DC-to-DC converters for controllably converting the DC voltage and providing at least one output DC voltage; and

a controller for connecting the pair of bidirectional DC-to-DC converters to operate in one of a parallel and a differential mode.

12. The apparatus of claim 11, wherein the controller coordinates operation of the pair of bidirectional DC-to-DC converters to reduce signal harmonics.

13. The apparatus of claim 11, wherein the controller reduces signal harmonics by controlling a phase relationship between duty cycles of the pair of bidirectional DC-to-DC converters.

14. The apparatus of claim 11, wherein the controller operates the pair of bidirectional DC-to-DC converters in parallel by electrically connecting a positive voltage output of one of the pair of bidirectional DC-to-DC converters to a positive voltage output of another of the pair of bidirectional DC-to-DC converters.

15. The apparatus of claim 14, wherein the controller operates the pair of bidirectional DC-to-DC converters differentially by electrically connecting a load between the positive voltage output terminals of each of the pair of bidirectional DC-to-DC converters.

16. The apparatus of claim 15, wherein the controller operates switches associated with a first of the pair of bidirectional DC-to-DC converters according to a first duty cycle and operates switches associated with a second of the pair of bidirectional DC-to-DC converters according to a second duty cycle, and wherein the first and second duty cycles are in phase with respect to one another.

17. The apparatus of claim 14, wherein the controller operates switches associated with a first of the pair of bidirectional DC-to-DC converters according to a first duty cycle and operates switches associated with a second of the pair of bidirectional DC-to-DC converters according to a second duty cycle, and wherein the first and second duty cycles are out of phase with respect to one another.

18. The apparatus of claim 17, wherein the first and second duty cycles are 180 degrees out of phase.

19. The apparatus of claim 11, wherein the controller operates the pair of bidirectional DC-to-DC converters such that each of the bidirectional DC-to-DC converters operates independently of the other.

20. The apparatus of claim 19, wherein the controller operates switches associated with a first of the pair of bidirectional DC-to-DC converters according to a first duty cycle and operates switches associated with a second of the pair of bidirectional DC-to-DC converters according to a second duty cycle, and wherein the first and second duty cycles are phased with respect to one another based upon a polarity of current through the first and second bidirectional DC-to-DC converters.

21. The system of claim 11, wherein said pair of bidirectional DC-to-DC converters each further comprise:

first and second switches;

an inductor connected in parallel between said first and second switches; and

a capacitor for isolating ripple currents generated by an associated one of said pair of bidirectional DC-to-DC converters.

22. A system for sinking and sourcing electrical power comprising:

a poly-phase utility port for connecting the system with an electrical utility;

a device connected to the poly-phase utility port for interfacing the poly-phase utility port with a DC bus to provide a first DC voltage level thereon;

at least one DC-to-DC converter for converting the first DC voltage level to at least one second DC voltage level; and

a controller for coordinating operation of the at least one DC to DC converter wherein the controller reduces current harmonics by controlling a phase relationship between duty cycles of the at least one DC-to-DC converter.

23. The system of claim 22, wherein said at least one DC-to-DC converter is a bidirectional DC-to-DC converter.

24. The system of claim 23, wherein said at least one bidirectional DC-to-DC converter further comprises:

first and second switches;

an inductor connected in parallel between said first and second switches; and

a capacitor for isolating ripple currents generated by said at least one bidirectional DC-to-DC converter.