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US 2016/0079879 A1Published application
Method For Controlling Of A Modular Converter
AssigneeABB Technology AG
InventorBeat Ronner
Life of this patent
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Abstract
A method for controlling a modular converter, having a plurality of M converter cells, including an active AC-to-DC converter operable in one of a plurality of modes; a DC-to-DC converter; a secondary side of said AC-to-DC converter and a primary side of said DC-to-DC converter connected in parallel with a DC-link capacitor, wherein the primary sides of the converter cells are connected in series, with a first converter cell connected to a line, preferably a medium voltage line, providing an AC line voltage an M-th converter cell connected to a ground; operated by a method placing the converters in bypassed, active or diode mode.
Claims16
A method for controlling a modular converter,
- a) the modular converter comprising a plurality of M converter cells, each converter cell comprising
- i) an AC-to-DC converter, a primary side of which represents a primary side of said converter cell, said AC-to-DC converter being an active AC-to-DC converter comprising a plurality of semiconductor switches, and operable in one of a plurality of modes, the plurality of modes comprising a bypassed mode, an active mode, and a diode mode;
- ii) a DC-to-DC converter, a secondary side of which represents a secondary side of said converter cell;
- with
- iii) a secondary side of said AC-to-DC converter and a primary side of said DC-to-DC converter connected in parallel with a DC-link capacitor, wherein
- b) the primary sides of the converter cells are connected in series, with a first converter cell connected to a line, preferably a medium voltage line, providing an AC line voltage U(t) having a peak value Û, and an M-th converter cell connected to a ground;
- the method comprising the steps of:
- c) for a given allowable range [Umin, Umax] of a DC-voltage UDC at the DC-link capacitor
- i) determining whether any integer number N≦M exists for which
- ii) Û/N<Umin, and
- iii) Û/(N−1)>Umax;
- and
- d) if the condition under c) is fulfilled
- i) selecting an integer number L with L<N,
- ii) selecting a first set of N−L converter cells,
- iii) selecting a second set of L converter cells,
- iv) putting the AC-to-DC converter of, preferably all, converter cells which have not been selected in steps ii) or iii) into bypassed mode,
- v) putting the AC-to-DC converter of, preferably all, converter cells from the first set into diode mode,
- vi) putting the AC-to-DC converter of, preferably all, converter cells from the second set into active mode.
16 more elements
A controller for controlling a modular converter,
- a) the modular converter comprising a plurality of M converter cells, each converter cell comprising
- i) an AC-to-DC converter, a primary side of which represents a primary side of said converter cell, said AC-to-DC converter being an active AC-to-DC converter comprising a plurality of semiconductor switches, and operable in one of a plurality of modes, the plurality of modes comprising a bypassed mode, an active mode, and a diode mode,
- ii) a DC-to-DC converter, a secondary side of which represents a secondary side of said converter cell, with
- iii) a secondary side of said AC-to-DC converter and a primary side of said DC-to-DC converter connected in parallel with a DC-link capacitance;
- wherein
- b) the primary sides of the converter cells are connected in series, with a first converter cell connected to a line, preferably a medium voltage line, providing an AC line voltage U(t) having a peak value Û, a and an M-th converter cell connected to a ground;
- the controller configured to perform the method comprising the steps of:
- c) for a given allowable range [Umin, Umax] of a DC-voltage UDC at the DC-link capacitor
- i) determining whether any integer number N≦M exists for which
- ii) Û/N<Umin, and
- iii) Û/(N−1)>Umax, and
- d) if the condition under c) is fulfilled
- i) selecting an integer number L with L<N,
- ii) selecting a first set of N−L converter cells,
- iv) putting the AC-to-DC converter of, preferably all, converter cells which have not been selected in steps ii) or iii) into bypassed mode,
- v) putting the AC-to-DC converter of preferably all, converter cells from the first set into diode mode,
- vi) putting the AC-to-DC converter of, preferably all, converter cells from the second set into active mode.
14 more elements
Dependencies are inferred from the claim text.