DEVICE FOR PROTECTION OF MATRIX CASCADE FREQUENCY CONVERTER Russian patent published in 2013 - IPC H02M5/27 

FIELD: electrical engineering.

SUBSTANCE: device for protection of a matrix cascade frequency converter that contains (in every m-phase of the power part) n cascades (matrixes) of bridge circuits on IGBT-modules (the outputs of each cascade bridge circuits, via contactors, are connected to (mxn) potentially loose 3-phase power supplies, a microprocessor control system (CS) generating controlling opto-signals for the driver devices performing the bridge circuit cascades keys switching on/off and current protection; the protection device consists of (m×n) units with balancing capacitor, each of them connected (via a 3-phase rectifier), to the said bridge circuits inputs; introduced into each unit circuit are a current sensor and a threshold element (varistor) placed in series with the balancing capacitor bypassed with a dummy burden resistor; the current sensors outputs are summed in pairs and connected (via the signal converters boards) to the CS that ensures (relying on a signal from the current sensor) snowballing processes of switching off the keys of IGBT-modules of the other cascades in the same or other phases and contactors switching off at the inputs of each cascade bridge circuits.

EFFECT: triggering reliability enhancement combined with the implementation process simplification.

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