Electric power conversion systems – Current conversion – Including d.c.-a.c.-d.c. converter
Patent
1995-12-18
1997-04-15
Wong, Peter S.
Electric power conversion systems
Current conversion
Including d.c.-a.c.-d.c. converter
363 22, 363 98, H02M 3335, H02M 324, H02M 542, H02M 744
Patent
active
056216211
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a power unit which includes a self-oscillating series-resonance converter and which functions to supply a load, such as an electric bulb, a battery charger and/or electronic equipment, wherein the series-resonance converter includes two mutually connected transistors, each of which is intended to be activated by a control transformer, and a series-connected inductor and capacitor, and wherein each transistor and a corresponding series-connected capacitive voltage divider belonging to the transistor and/or a further transistor is connected in parallel with the inductor, capacitor and control transformer, and wherein the load is connected across the capacitor.
A power unit of the aforedescribed kind is known to the art and is found described, for instance, in Swedish Patent Specification No. 7512267-1. This power unit operates in accordance with the series-resonance principle and provides many advantages over other known power units. These advantages include low switch losses at high operating frequencies, while problems relating to radio interference or disturbance are negligible.
One of the drawbacks with a power unit that operates in accordance with the series-resonance principle is that it requires the presence of complicated drive electronics. This results in a high total cost for the manufacture of such a power unit. Since there is a high demand for power units which can be used in low-price equipment, it is desirable to make the drive circuits of the power unit as cheap as possible.
SUMMARY OF THE INVENTION
A power unit including a self-oscillating series resonance converter which is intended to supply a load, for instance an electric bulb, a battery charger and/or electronic equipment. The series resonance converter includes two mutually connected transistors, each of which is activated by a respective control transformer, and further includes an inductor and a capacitor which are connected in series. Each transistor and an associated series-connected capacitive voltage divider and/or a further transistor are connected in parallel with the inductor, capacitor and control transformer. The load is connected across the capacitor. The magnetic flux through the control transformer can be influenced by a magnetic flux applied externally via an electromagnet to change the oscillation frequency of the transistors and therewith the voltage output of the power unit.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with reference to the accompanying drawings, wherein:
FIG. 1 is a circuit diagram for a power unit operating in accordance with the series-resonance principle.
FIG. 2 is a diagram which illustrates a voltage/current relationship in the power unit.
FIG. 3 is a circuit diagram for the power unit according to FIG. 1, said circuit enabling the magnetic flux through the control transformer belonging to the power unit to be regulated or adjusted.
FIG. 4 is a view from above of the arrangement of a power unit control transformer having an electromagnet connected externally thereto in accordance with the principles of the invention.
FIG. 5 is a circuit diagram which relates to a modified version of the power unit illustrated in FIG. 3.
DETAILED DESCRIPTION
The manner of operation of the power unit illustrated in FIG. 1 will now be described.
When the power unit is connected to the mains voltage, which in the present case reaches an alternating voltage of 220 volts, the voltage is rectified with the aid of four bridge-connected rectifier diodes D1-D4. The full-wave rectified mains voltage is filtered downstream of the diode bridge with the aid of a first capacitor C1. The direct voltage across the capacitor C1 will reach about 310 volts. A current which charges a capacitor C2 now passes through a resistor R1. When the voltage across this latter capacitor C2 has risen to above the threshold voltage of a trigger diode D5, the trigger diode is ignited or fired and conducts current to the base of a first tra
REFERENCES:
patent: 4424556 (1984-01-01), Maeda et al.
patent: 4437136 (1984-03-01), Yamamoto
patent: 4851739 (1989-07-01), Nilssen
patent: 5111380 (1992-05-01), Nilssen
patent: 5132889 (1992-07-01), Hitchcock et al.
patent: 5198969 (1993-03-01), Redl et al.
Lindmark Electric AB
Vu Bao Q.
Wong Peter S.
LandOfFree
Power unit having self-oscillating series resonance converter 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 unit having self-oscillating series resonance converter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power unit having self-oscillating series resonance converter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-365920