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EP0255258A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Digitally controlled A.C. to D.C. power conditioner that draws sinusoidal input current

Assignee: Unisys Corp
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Filing: 1987-07-14
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Granted: —
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Expires: 2007-07-14
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Abstract

Abstract An A.C. to D.C. power conditioner, which draws sinusoidal input current utilizes digital proportional-­integral control to provide output voltage regulation by adjusting the gain of a current program loop. The current program loop controls the state of a power switch to force the instantaneous average current in an inductor to follow the instantaneous rectified line voltage. Variable hysteresis control provides noise immunity by increasing the ripple current in an iron-cored filter inductor when the instantaneous input voltage is high. Digital proportional-integral (PI) control provides output voltage regulation by adjusting, in discrete steps, the gain of the current program loop. A multiplying digital-to-analog converter serves as an interface between the voltage regulation loop and the current program loop. The sampling rate of the PI controller is determined by the input line frequency, which allows good transient response to be obtained. The current program loop forces the current drawn by the power conditioner to follow the input A.C. line voltage, thereby electronically emulating a resistor.

Inventors

  • 👤 Christopher P. Henze

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-29 02:35
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/42; H02M1/4208; H02M1/4225; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156; H02M3/157; H02M7/00; H02M7/02; H02M7/04; H02M7/12; H02M7/21; H02M7/217; H02M1/0003; H02M1/0012

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 89 words
In a power conditioner for providing a D.C. output voltage from a rectified A.C. input voltage source which comprises voltage output means and an inductor with a high permeability core, through which ripple current flows, which is coupled between said input voltage source and said voltage output means, the improvement comprising current control means for varying the magnitude of the peak-to-peak value of said ripple current in direct proportion to the magnitude of said instantaneous rectified input voltage such that the power conditioner draws a substantially sinusoidal input current.
Claim 2
Dependent Claim 89 words
In a power conditioner for providing a D.C. output voltage from a rectified A.C. input voltage source which comprises voltage output means and an inductor with a high permeability core, through which ripple current flows, which is coupled between said input voltage source and said voltage output means, the improvement comprising current control means for varying the magnitude of the peak-to-peak value of said ripple current in direct proportion to the magnitude of said instantaneous rectified input voltage such that the power conditioner draws a substantially sinusoidal input current.
Claim 3
Dependent Claim 19 words
In a power conditioner as claimed in claim 1, the improvement wherein said voltage output means comprises switching means.
Claim 4
Dependent Claim 88 words
In a power conditioner as claimed in claim 2 wherein said power conditioner supplies an output voltage and said current control means comprises a reference voltage, the improvement comprising comparison means for comparing said output voltage and said reference voltage, and for suppling an analog error signal representative of the difference of said output voltage and said reference voltage, and analog-to-digital converter means coupled to said comparison means to receive said analog error signal and to said switching means for controlling the switching frequency of said switching means.
Claim 5
Dependent Claim 51 words
In a power conditioner as claimed in claim 3, the further improvement wherein said analog-to-digital converter means comprises a sampling converter means and said power conditioner comprises sample control means coupled to receive the A.C. input signal for supplying a sampling signal upon each zero crossing of the A.C. input signal.
Claim 6
Dependent Claim 35 words
In a power conditioner as claimed in claims 3 or 4, the further improvement wherein said comparison means comprises a proportional integral controller which receives said analog error signal and produces a digital error signal.
Claim 7
Dependent Claim 147 words
In a power conditioner as claimed in claim 5 the further improvement wherein said switching means comprises a switch connected in shunt with said inductor and that has a control terminal and said power conditioner further comprises regulating means coupled to said com­parison means and to receive said instantaneous rectified input voltage and said digital error signal which comprises amplifier means for providing a turn-on output signal and a turn-off output signal, both of which have substantially the waveform as said rectified input signal, but which are of different amplitudes, measuring means coupled to said inductor and said amplifier means for providing an inductor signal representative of the instantaneous current flowing in said inductor, and on-off means coupled to said amplifier means and to said switching means for controlling the switching of said switching means in response to said inductor signal and said turn-on and turn-off signals.
Claim 8
Dependent Claim 22 words
In a power conditioner as claimed in any of the preceding claims the improvement wherein said output means comprises output filter means.

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