Controlling a modular converter
AssigneeABB Technology AG
InventorsAkos MESTER, Drazen DUJIC, Thomas BESSELMANN
Life of this patent
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Abstract
A modular converter is disclosed which includes plural converter cells connected in series on a first side, and connected on a second side, wherein each converter cell includes an AC-to-DC converter connected to the first side and a DC-to-DC converter connected to the second side. Exemplary embodiments estimate power transferred by the modular converter; compare the transferred power with a threshold value; when the transferred power exceeds the threshold value, operate in a normal load operation mode; when the transferred power is below the threshold value, operate in a low load operation mode with reduced switching losses.
Claims20
A method for controlling a modular converter having a plurality of converter cells which are connected in series on a first side and are connected with each other on a second side, wherein each converter cell includes an active front-end AC-to-DC converter connected to the first side and a DC-to-DC converter connected to the second side, the method comprising:
- a) estimating power transferred by the modular converter;
- b) comparing the transferred power with a threshold value;
- c) when the transferred power exceeds the threshold value, operating the modular converter in a normal load operation mode;
- and
- d) when the transferred power is below the threshold value, operating the modular converter in a low load operation mode, in which the converter cells are operated, such that switching losses are reduced with respect to the normal load operation mode;
- wherein the method includes:
- e) in the low load operation mode:
- (i) a number of DC-to-DC converters of the converter cells are deactivated;
- (ii) the AC-to-DC converters are run in an intermittent mode;
- and/or
- (iii) a minimum number of required converter cells is determined based on the transferred power, with not required converter cells being bypassed by short-circuiting input terminals of the not required converter cells.
A controller for a modular converter, wherein the controller is configured with a computer processer stored in a non-transitory medium which, when executed by the controller, will cause the controller to perform functions of:
- a) estimating power transferred by the modular converter;
- b) comparing the transferred power with a threshold value;
- c) when the transferred power exceeds the threshold value, operating the modular converter in a normal load operation mode;
- d) when the transferred power is below the threshold value, operating the modular converter in a low load operation mode, in which the converter cells are operated, such that switching losses are reduced with respect to the normal load operation mode;
- wherein
- e) in the low load operation mode:
- (i) a number of DC-to-DC converters of the converter cells are deactivated;
- (ii) the AC-to-DC converters are run in an intermittent mode;
- and/or
- (iii) a minimum number of required converter cells is determined based on the transferred power, with not required converter cells being bypassed by short-circuiting input terminals of the not required converter cells.
Dependencies are inferred from the claim text.