US 4,788,451 A · AC voltage stabilizer easily convertible into uninterruptible power supply (UPS)

Abstract

An electronic AC voltage stabilizer using a class B amplifier output stage which is fed by a full-wave rectified sinewave voltage. The input voltage to (the phase inverter of) the class B amplifier output stage is kept in phase with the aforesaid sinewave voltage, which causes the power losses in the output stage to be very low. As compared to other electronic AC stabilizers, the apparatus according to the invention offers high efficiency and simplicity. The AC stabilizer can easily be converted into a true uninterruptible power supply (UPS) by adding a battery which through a battery interface circuit connects the battery voltage, after it has been appropriately converted into a full wave rectified sinewave voltage, to the push pull amplifier output stage when a power network fails.

Claims12

Dependent claims

A stabilizer for supplying stable AC voltage to a load from a source of incoming AC voltage, said stabilizer comprising:

an output stage, operative in response to a sinusoidal control voltage and to a network bubble voltage, for providing said stable AC voltage, said output stage having at least two output transistors connected in a push-pull configuration through coupling means to a load and powered by the network bubble voltage;
means for full-wave rectifying an incoming AC voltage to produce said network bubble voltage;
and
means responsive to said incoming AC voltage for producing said control voltage such that said control voltage is phase-locked to said incoming AC voltage in order that the voltage appearing between the collector and emitter of each of said transistors is phase-locked to and synchronous in frequency with said network bubble voltage whereby a relatively low amount of power is dissipated by each of said transistors.

1 more element

A stabilizer for supplying stable AC voltage to a load from a source of incoming AC voltage, said stabilizer comprising:

means for producing a DC voltage from said incoming AC voltage;
a sine-wave oscillator for producing a sinusoidal control voltage;
a pulse width modulator, responsive to the sinusoidal control voltage and to said DC voltage, for producing a pulse width modulated DC voltage;
an output stage, operative in response to the sinusoidal control voltage and to a feeding bubble voltage, for providing said stable AC voltage, said output stage having at least two output transistors connected in a push-pull configuration through coupling means to a load and powered by the feeding bubble voltage;
and
means for integrating said pulse width modulated DC voltage to produce a source of full-wave rectified voltage and applying this rectified voltage as said feeding bubble voltage to said output stage, whereby said feeding bubble voltage is phase-locked and synchronous with said control voltage thereby substantially reducing the amount of power dissipated by each of said transistors.

3 more elements

Dependencies are inferred from the claim text.

AC voltage stabilizer easily convertible into uninterruptible power supply (UPS)

Life of this patent

AC voltage stabilizer easily convertible into uninterruptible power supply (UPS)

Life of this patent

Abstract

Claims12