Patent ID: 9667189
Date: 2017-05-30
CPC Classifications: H02P

Claim:
1. A method comprising: operating an electrically excited synchronous machine (EESM) system in a first control mode, the system including a converter operatively coupled with one or more stator windings, an exciter operatively coupled with one or more field windings, a control system operatively coupled with the converter and the exciter and including a DTC controller structured to receive a torque reference input and to provide switching commands to the converter, and a power supply operatively coupled with the converter and the exciter, the first control mode providing a first torque reference to the DTC controller; determining with the control system whether a power supply fault condition exists; determining with the control system whether the EESM system is operating in one of a motor mode and a generator mode; if the power supply fault condition exists and the EESM system is operating in the motor mode, entering one of a motor ride through control mode and a motor controlled braking control mode, the motor ride through control mode and the motor controlled braking control mode providing a second torque reference to the DTC controller, the second torque reference being determined differently from the first torque reference; and if the power supply fault condition exists and the EESM system is operating in the generator mode, entering one of a generator ride through control mode and a generator controlled braking control mode, the generator ride through control mode providing the first torque reference to the DTC controller, and the generator controlled braking control mode providing a third torque reference to the DTC controller, the third torque reference being determined differently from the first torque reference and the second torque reference.