Converter device and uninterruptible power supply equipped with such a device
A converter device comprising a power supply input, rectifier means, switching means, control means, and a switching aid circuit, said switching aid circuit comprising inductive means, branch-off means of an input current, and power storage means. The device of the invention is characterized in that the inductive means are essentially formed by a transformer directly connected to the power supply input and comprising reverse-coiled windings, and that the branch-off means comprise auxiliary switching means directly connected between said inductive means and a voltage reference or an output line to establish branch-off of the input current onto said inductive means before main turn-on. An uninterruptible power supply comprising the converter device described above.
1. A unidirectional converter device for supplying a DC output voltage on an output line, said device including at least one switching unit comprising:
a power supply input to which an input voltage is applied,
rectifier means connected to said power supply input for supplying the output voltage,
switching means connected to said power supply input for a main turn-on or turn-off of an input current so that, when main turn-off occurs, an input current is diverted to said rectifier means,
control means for said switching means,
a switching aid circuit connected between the power supply input and the output line for establishing a switching voltage equal to zero before main turn-on, said switching aid circuit comprising inductive means and branch-off means branching off of the input current to said inductive means before main turn-on, and
power storage means parallel-connected on the switching means for establishing a resonance of said current in the inductive means before main turn-on,
wherein said inductive means comprise a transformer directly connected to the power supply input, and comprising at least one first winding, at least one second winding reverse-coiled with respect to the first winding, and the branch-off means comprise auxiliary switching means directly connected either between said inductive means and a voltage reference or between said inductive means and the output line.
2. The device according to claim 1 , wherein the first winding is connected between the power supply input and the branch-off means, and the second winding is magnetically coupled to the first winding and connected between said power supply input and the output line or between the power supply input and the voltage reference.
3. The device according to claim 1 , wherein the transformer presents a transformation ratio of less than one.
4. The device according to claim 2 , wherein a first reverse-blocking diode is connected between the first winding and the output line or between the first winding and the voltage reference.
5. The device according to claim 4 , wherein a second reverse-blocking diode is connected between the second winding and the output line or between the second winding and a voltage reference.
6. The device according to claim 2 , wherein the auxiliary switching means comprise an auxiliary transistor directly connected between the first winding and the voltage reference or between the first winding and the output line, said auxiliary transistor for supplying to the transformer windings a voltage having a value that is a function of the output voltage on main turn-off and at the moment turn-on of said auxiliary transistor takes place.
7. The device according to claim 1 , wherein the control means comprise a delay module for forcing a delayed main turn-on after a longer period than a predefined period.
8. The device according to claim 7 , wherein the control means are connected to the auxiliary switching means and comprise a module for triggering current branch-off during a longer period than the predefined period.
9. The device accord according to claim 1 , wherein the rectifier means comprise a diode for a current input to the power supply input.
10. The device according to claim 1 , wherein the power storage means comprise a first capacitor parallel-connected with the rectifier means and a second capacitor parallel-connected with the switching means.
11. An uninterruptible power supply comprising a power supply input to which a variable input voltage can be applied, a rectifier connected to said input, at least one DC voltage line connected to an output of the rectifier, an inverter connected to a voltage line and comprising an output for supplying a variable output voltage, wherein the rectifier is a converter device according to claim 1 for supplying DC output voltage on said line.