Electric power conversion systems – Current conversion – With condition responsive means to control the output...
Patent
1981-04-30
1983-07-19
Shoop, William M.
Electric power conversion systems
Current conversion
With condition responsive means to control the output...
318345G, 318803, H02P 1324
Patent
active
043947239
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates generally to a power supply circuit and, more particularly, to a power supply circuit for supplying power to an inductive load in response to a 3-phase AC source.
2. Background Art
In many power supply circuits, the power supply can be controlled to adjust or change the current through the load. The power supply can be, for example, a DC supply generated from a 3-phase AC source and the load can be, for example, an inductive load. Current will build up or decay in response to the supply being coupled to or decoupled from the load.
Under certain conditions, it can be important to control the rate of change of current through the inductive load, e.g., to build-up or to decay very rapidly, the current through the inductive load. However, various problems or constraints limit the rate at which this build-up or decay of the current can occur. The constraints for current build-up and decay are the magnitude of the power supply voltage and the inductance of the inductive load. These constraints can make a power supply circuit unsuitable for any application in which the response time for achieving maximum current build-up or current decay must be very short.
As one example, the inductive load can be an eddy current dynamometer which is used to control the speed of an engine. The power supply can be a DC supply of one magnitude or polarity of voltage which is coupled to the inductive load to build up current through the load in response to a command for reduced engine speed and/or a DC supply of a different magnitude or polarity of voltage to the load to decay current through the load in response to a command for increased engine speed. But, the commanded engine speed may have to be reached so rapidly, that the response time for achieving current build-up or decay cannot occur sufficiently quickly for either command due to the above-mentioned constraints.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a power supply circuit is provided, having a load, means for conducting current of a 3-phase AC source, and triggerable means for coupling the current of the 3-phase AC source between said conducting means and said load, the improvement comprising means for generating a reference phase signal in response to one reference phase voltage of the 3-phase AC source, and means for triggering said triggerable means at preselected phase angles of the 3-phase AC source relative to the reference phase signal to control the current through the load.
Several constraints, such as the magnitude of the power supply voltage and the inductance of the load, limit the rate of current build-up or decay of current through the load. The power supply circuit of the present invention couples the current of the 3-phase AC source between the coupling means and the load, at various phase angles relative to the reference phase voltage, to control the current through the load. A maximum rate of current build-up or decay through the load is obtained at preselected phase angles.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-7A illustrate voltage waveforms of a 3-phase AC source used to explain the theory of operation of the present invention for control of current build-up through a load.
FIGS. 1B-7B show current flow through a circuit portion of a power supply circuit of the present invention at times corresponding to phase angles shown, respectively, in FIGS. 1A-7A;
FIGS. 8A-13A and FIG. 13A' illustrate voltage waveforms of the 3-phase AC source used to explain the theory of operation of the present invention for control of current decay through a load;
FIGS. 8B-12B show current flow through a circuit portion of the power supply circuit of the present invention at times corresponding to phase angles shown, respectively, in FIGS. 8A-13A;
FIG. 14A is a composite illustration for explaining current build-up and current decay through a load;
FIG. 15 is a schematic illustration of
REFERENCES:
patent: 4016468 (1977-04-01), Graf
patent: 4017744 (1977-04-01), Johnson
patent: 4028609 (1977-06-01), Deterino
patent: 4053945 (1977-10-01), Dumas
patent: 4063146 (1977-12-01), Oliver
patent: 4169372 (1979-10-01), Colwill et al.
patent: 4347562 (1982-08-01), Galloway
Caterpillar Tractor Co.
Noe Stephen L.
Shoop William M.
LandOfFree
Power supply circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Power supply circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power supply circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-754687