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Method of Obtaining Three Tightly Regulated Levels Out of Two Pulse-Width Modulation Power Trains Using Pulse-Position Modulation

IP.com Disclosure Number: IPCOM000044467D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Mussenden, GA: AUTHOR

Abstract

This article describes a technique for super-position of two pulse- width modulation (PWM) power trains to obtain a third tightly regulated train and the use of phase shifting to control its DC voltage. In the technique disclosed in a multilevel, multi-train power system, the number of post-regulators can be drastically reduced or eliminated so that a substantial number of space- and power-consuming devices are eliminated. The technique is illustrated in the block diagram of Fig. 1. Referring to Fig. 1, PWM systems A and B shown as blocks 1A and 1B, respectively, are standard PWM power trains which have respective voltage outputs Va(t) and Vb(t) of period T, as shown in Figs. 2 and 3.

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Method of Obtaining Three Tightly Regulated Levels Out of Two Pulse- Width Modulation Power Trains Using Pulse-Position Modulation

This article describes a technique for super-position of two pulse- width modulation (PWM) power trains to obtain a third tightly regulated train and the use of phase shifting to control its DC voltage. In the technique disclosed in a multilevel, multi-train power system, the number of post-regulators can be drastically reduced or eliminated so that a substantial number of space- and power-consuming devices are eliminated. The technique is illustrated in the block diagram of Fig. 1. Referring to Fig. 1, PWM systems A and B shown as blocks 1A and 1B, respectively, are standard PWM power trains which have respective voltage outputs Va(t) and Vb(t) of period T, as shown in Figs. 2 and 3. These power trains have their respective outputs averaged out of the averaging networks 2A and 2B which produce the respective DC output voltages Va and Vb. Voltages Va and Vb are respectively fed back to the pulse-width stages 1A and 1B and the widths ta and tb regulated in a closed loop as to obtain constant, fixed Va and Vb which have respective values of Ata/T and Btb/T. Both 1A and 1B receive the same frequency train from frequency generator 1D, but the frequency input for 1B is obtained via the phase shifting circuit 2D, which provides a phase difference td between Va(t) and Vb(t), as shown in Fig. 4. The two phase-displaced functions are then fed...