Patent ID: 7973517

Claim:
A control device for a power converter, which is connected to a polyphase AC generator-motor including an armature winding and a field winding, the power converter comprising: a bridge rectifier circuit including switching elements of a positive pole-side arm and switching elements of a negative pole-side arm, for controlling energization of the armature winding; and a field circuit for controlling energization of the field winding by using a field switching element, wherein the control device controls switching of the switching elements of the bridge rectifier circuit and the field switching element of the field circuit, wherein the control device comprises: B-terminal voltage detection means for detecting a B-terminal voltage generated between a B-terminal being to a power input/output terminal of the polyphase AC generator-motor and a reference potential; field current detection means for detecting a field current flowing through the field winding; field current control means for controlling the field current based on a detected value of the field current; abnormal voltage detection means for detecting whether or not a voltage value of the B-terminal voltage is equal to or higher than a predetermined voltage value; and negative pole-side arm short-circuiting means for bringing all the switching elements of the negative pole-side arm into conduction when the abnormal voltage detection means detects that the voltage value of the B-terminal voltage is equal to or higher than the predetermined voltage value, wherein, when the abnormal voltage detection means detects that the voltage value of the B-terminal voltage is equal to or higher than the predetermined voltage value, the control device causes the negative pole-side arm short-circuiting means to bring all the switching elements of the negative pole-side arm into conduction and to interrupt all the switching elements of the positive pole-side arm, and causes the field current control means to limit the field current.