Active snubber
First Claim
1. Switching cells for phase legs of a power converter, the switching cells comprising:
- a power switch for conducting a current for driving a load;
a series connection comprising an auxiliary switch and a cell capacitor coupled in series, the series connection coupled in parallel with the power switch;
a cell inductor coupled to a coupling of the power switch and the series connection; and
a commutation loop to conduct a commutation current arising from turn-off of the power switch, the loop comprising;
a first bypass circuit for blocking current flow in a first direction and coupled in parallel with the power switch to conduct the commutation current in another, direction opposite the first direction;
a second bypass circuit for blocking current flow in a second direction and coupled in parallel with the auxiliary switch to conduct the commutation current in a direction opposite the second direction; and
the cell capacitor;
at least one control input line for receiving a control signal and configured to drive a control terminal of the power switch and a control terminal of the auxiliary switch; and
a series connection of the switching cells, each switching cell of the series connection being coupled to an adjacent one of the switching cells by a respective one of cell inductors.
1 Assignment
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Accused Products
Abstract
The present invention generally relates to a switching cell for a phase leg of a power converter and a method of controlling a power converter to drive a load, and more particularly to a plurality of such switching cells, a phase arm for a power converter, a power converter phase leg, to a power converter for driving a load, and methods of making a power converter. A switching cell for a phase leg of a power converter may comprise: a power switch for conducting a current for driving a load; a commutation path coupled in parallel with the power switch, the commutation path comprising a cell capacitor and an auxiliary switch coupled in series, the auxiliary switch configured to allow control of a conduction state of the commutation path; and a cell inductor coupled to a coupling of the power switch and the commutation path, wherein the switching cell comprises at least one control input line for receiving a control signal, the at least one control input line configured to drive a control terminal of the power switch and a control terminal of the auxiliary switch.
13 Citations
23 Claims
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1. Switching cells for phase legs of a power converter, the switching cells comprising:
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a power switch for conducting a current for driving a load; a series connection comprising an auxiliary switch and a cell capacitor coupled in series, the series connection coupled in parallel with the power switch; a cell inductor coupled to a coupling of the power switch and the series connection; and a commutation loop to conduct a commutation current arising from turn-off of the power switch, the loop comprising; a first bypass circuit for blocking current flow in a first direction and coupled in parallel with the power switch to conduct the commutation current in another, direction opposite the first direction; a second bypass circuit for blocking current flow in a second direction and coupled in parallel with the auxiliary switch to conduct the commutation current in a direction opposite the second direction; and the cell capacitor; at least one control input line for receiving a control signal and configured to drive a control terminal of the power switch and a control terminal of the auxiliary switch; and a series connection of the switching cells, each switching cell of the series connection being coupled to an adjacent one of the switching cells by a respective one of cell inductors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of controlling a power converter to drive a load, the power converter having a phase leg coupled between two power rails and comprising two arms each having a switching cells and coupled at an output of the power converter, wherein each of the switching cells comprises:
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a respective power switch for conducting a current for driving the load; a respective series connection comprising an auxiliary switch and a cell capacitor coupled in series, the series connection coupled in parallel with the power switch; a respective cell inductor coupled to a coupling of the power switch and the series connection; and a commutation loop to conduct a commutation current arising from turn-off of the power switch, the loop comprising; a first bypass circuit for blocking current flow in a first direction and coupled in parallel with the power switch to conduct a commutation current in a second direction, opposite to the first direction; a second bypass circuit for blocking current flow in the second direction and coupled in parallel with the auxiliary switch to conduct a commutation current in the first direction; and the cell capacitor, the method comprising at least one step of; switching a first number of switching cells of one of the arms ON and a second number of the switching cells of the other of the arms OFF to advance a voltage profile at the output of the converter and maintain a voltage across the phase leg, switching the first number of switching cells ON by turning the power switch of the switching cell ON and the auxiliary switch of the switching cell OFF, the first and second numbers being one or more. - View Dependent Claims (20, 21, 22, 23)
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Specification