US 4,369,490 AGranted

Low-ripple power rectifier system

AssigneePatent-Treuhand Gesellschaft fur Elektrische Gluhlampen GmbH

InventorFrithjof Blum

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Abstract

To provide a power rectifier for connection to an a-c power network which has low ripple at the d-c output, and low harmonic content at the a-c side, particularly for feeding a d-c - a-c inverter frequency generator providing output in the audio or low supersonic range for supply of gas discharge or fluorescent lamps, a wave-shaping network is connected to the a-c side of a standard bridge rectifier unit such that the a-c power applied to the rectifier is of approximately trapezoidal or rectangular or square-wave shape; a suitable network is the combination of an inductance (D) and a storage capacitor(C1) in a T-network or in a series resonant circuit, in which the quadrature VA of the choke (D), at network frequency, is about 60% of the power to be supplied by the rectifier, with a capacitor (C1) in a T-network configuration of such value that the resonant frequency of the L/C circuit is about 2.2 to 2.6 times network frequency or equal to network frequency, when in a series resonant circuit. Splitting the inductance (D) into two winding portions, one in each one of the supply lines substantially reduces radio interference from a connected gas discharge lamp.

Claims13

Dependent claims

Low-ripple low-harmonic reflecting rectifier system, particularly for coupling to an a-c power network and to receive a-c power input, and to provide d-c power output to a d-c semiconductor circuit, especially to supply a discharge lamp inverter circuit from a-c power terminals (Ph, Mp;

9, 10), having
a-c network terminals;
a rectifier circuit (1), having an input and an output;
a filter capacitor (C2) connected across the d-c output of the rectifier circuit;
and comprising, in accordance with the invention,
an a-c wave-shaping and wave-transforming network means (D;
C1) connected to receive the a-c voltage from the power network in sinusoidal wave shape and converting said sinusoidal wave shape to a wave shape which is approximately of trapezoidal shape including
the combination of storage inductance means (D), and a storage capacitor (C1) connected to the a-c network terminals,
the storage inductance (D) being connected between the network terminals and the input to the rectifier circuit in serial connected, and the storage capacitor (C1) being connected in parallel across the input to the rectifier circuit,
and dimensioned and matched with respect to each other and the frequency of the voltage supplied by the a-c network in sinusoidal wave shape, to have a resonant frequency greater than twice network frequency but less than three times network frequency.

7 more elements

Dependencies are inferred from the claim text.