An electrical machine includes a with a parallel first and second phase windings. A first neutral bus is connected to the first phase winding and a second neutral bus is connected to the second phase winding. A first voltage sensor is coupled to the first neutral bus and a second voltage sensor coupled to the second phase winding for monitoring current imbalance between the first and second phase windings.

When a state where a power-generation voltage of a vehicle AC power generator is the same as or lower than a predetermined voltage has continued for a predetermined time or longer, a power generation controller stops or disables a low-voltage protection circuit from performing its operation so that an unintentional voltage rise caused by the low-voltage protection circuit is prevented.

A battery pack monitor includes a portable housing, a controller within the housing, and a memory communicatively connected to the controller. The battery pack monitor further includes a power source positioned within the housing and operatively connected to the controller. The battery pack monitor includes a battery pack connector comprising a wired battery interface electrically connectable between the controller and a battery pack management system of a high voltage battery pack. The controller includes executable instructions which, when executed, cause the controller to receive, via the wired battery interface, status information from the high voltage battery pack, store the status information in the memory, and based on the status information, generate one or more battery status alerts. In examples, the battery pack monitor includes a wireless interface for communication with a remote system for logging status information, and may have a diagnostics connector to allow connection of additional diagnostic equipment.

A system including a generator and a controller. The generator includes a permanent magnet generator (PMG), and an exciter. The controller manages operations of the generator. The controller includes an alternating current to direct current (AC-to-DC) converter that generates a direct current (DC) voltage, an exciter drive that provides a DC current to the exciter of the generator using the DC voltage created by the AC-to-DC converter in accordance with the control signal, and a regulator controller that drives the active AC-to-DC converter.

A method of controlling output of an ESS depending on droop control according to frequency variation range of a power grid in the present invention may comprise steps of: monitoring the frequency variation range of the power grid; predicting frequency correction range resulting from regulation of an engine generator during a predetermined unit regulation time if the frequency variation range is determined to exceed a first reference value; controlling the output of the ESS with an output value determined by a frequency of the power grid according to a droop control algorithm set as a default if the predicted frequency correction range does not exceed a second reference value; and fixing the output of the ESS during the unit regulation time if the predicted frequency correction range exceeds the second reference value.

A method of controlling output of an ESS depending on droop control according to frequency variation range of a power grid in the present invention may comprise steps of: monitoring the frequency variation range of the power grid; predicting frequency correction range resulting from regulation of an engine generator during a predetermined unit regulation time if the frequency variation range is determined to exceed a first reference value; controlling the output of the ESS with an output value determined by a frequency of the power grid according to a droop control algorithm set as a default if the predicted frequency correction range does not exceed a second reference value; and fixing the output of the ESS during the unit regulation time if the predicted frequency correction range exceeds the second reference value.

Systems and methods for voltage regulation of high voltage direct current systems are provided. In certain embodiments, a system includes a generator that generates alternating current (AC) voltage. The system further includes a power converter that converts the AC voltage into regulated direct current (DC) voltage. Also, the system includes a voltage regulator. In additional embodiments, the voltage regulator includes an AC voltage regulator that regulates the AC voltage generated by the generator. Also, the voltage regulator includes a DC voltage regulator that regulates the DC voltage produced by the power converter. Moreover, the voltage regulator includes a regulator selector that selectively activates one of the AC voltage regulator and the DC voltage regulator based on a current from the power converter and at least one of a voltage of the generator and a voltage of the power converter.

In the field of power system stability there is provided a method of predicting the presence of an out-of-step condition in a power system that includes a plurality of generators, the method including the steps of: (a) obtaining a differential value ({tilde over (δ)}.sub.COI.sup.k) between a rotor angle (δ.sub.k) of an individual one of the plurality of generators and an equivalent rotor angle (δ.sub.COI.sup.k) of the centre of inertia of the remainder of the plurality of generators; (b) processing the differential value ({tilde over (δ)}.sub.COI.sup.k) to determine whether the differential value ({tilde over (δ)}.sub.COI.sup.k) is predicted to reach a predefined reference threshold (δ.sub.threshold); and (c) predicting the presence of the out-of-step condition in the power system if the differential value ({tilde over (δ)}.sub.COI.sup.k) is predicted to reach the predefined reference threshold (δ.sub.threshold).

In the field of power system stability there is provided a method of predicting the presence of an out-of-step condition in a power system that includes a plurality of generators, the method including the steps of: (a) obtaining a differential value ({tilde over (δ)}.sub.COI.sup.k) between a rotor angle (δ.sub.k) of an individual one of the plurality of generators and an equivalent rotor angle (δ.sub.COI.sup.k) of the centre of inertia of the remainder of the plurality of generators; (b) processing the differential value ({tilde over (δ)}.sub.COI.sup.k) to determine whether the differential value ({tilde over (δ)}.sub.COI.sup.k) is predicted to reach a predefined reference threshold (δ.sub.threshold); and (c) predicting the presence of the out-of-step condition in the power system if the differential value ({tilde over (δ)}.sub.COI.sup.k) is predicted to reach the predefined reference threshold (δ.sub.threshold).

A trim head drive is provided. The trim head drive includes a nonlinear power supply. The nonlinear power supply includes an output and a return connected to a trim coil of a generator. An output of the nonlinear power supply directly drives a trim coil to control an output frequency of the generator. The nonlinear power supply varies the output positively and negatively to either sink or source a trim head current to control an output frequency of the generator.