A voltage difference is determined between the observed voltage and a reference direct current bus voltage. A quadrature-axis (q-axis) voltage command is outputted based on a current difference derived from the voltage difference. A commanded direct-axis (d-axis) voltage is determined based on a measured d-axis current and a determined d-axis reference current derived from a mathematical relationship between d-axis residual voltage, the observed voltage and the commanded q-axis voltage, where residual voltage is proportional to a function of the observed voltage and the commanded q-axis voltage. An inverse Parks transformation module or a data processor provides one or more phase voltage command based on inverse Parks transform of the commanded voltages.

A master generator is configured to use a duty upper limit value and a duty lower limit value to perform duty restriction processing on a PWM signal in continuous Y cycles out of generated X cycles, and transmit the PWM signal after the restriction processing to a slave generator. The slave generator is configured to receive the PWM signal after the restriction processing transmitted from the master generator as a received PWM signal, and determine that a reception abnormality exists when the received PWM signal is received as a signal representing a duty less than the duty lower limit value or a duty more than the duty upper limit value in continuous (XY+1) cycles.

A master generator is configured to use a duty upper limit value and a duty lower limit value to perform duty restriction processing on a PWM signal in continuous Y cycles out of generated X cycles, and transmit the PWM signal after the restriction processing to a slave generator. The slave generator is configured to receive the PWM signal after the restriction processing transmitted from the master generator as a received PWM signal, and determine that a reception abnormality exists when the received PWM signal is received as a signal representing a duty less than the duty lower limit value or a duty more than the duty upper limit value in continuous (XY+1) cycles.

An electric generator, comprising a permanent magnet plurality of coils each activatable by selectively providing direct current thereto and at least one capacitor, wherein the electric generator is configured to recover energy stored in at least one of the coils into the at least one capacitor when the direct current is switched off.

An electric generator, comprising a permanent magnet plurality of coils each activatable by selectively providing direct current thereto and at least one capacitor, wherein the electric generator is configured to recover energy stored in at least one of the coils into the at least one capacitor when the direct current is switched off.

An alternator for generating electrical power to one or more components of a power network includes a machine portion including a stator, a rotor and a rectifier, a battery connection terminal connected to the machine portion and configured to be connected to a battery, and an isolation device integral to the alternator. The isolation device is located on an electrical path between at least the machine portion and the battery connection terminal, and the isolation device is configured to isolate at least one of the alternator and another component of the power network from receiving electric current from the battery based on an undesirable condition occurring in the power network.

An alternator for generating electrical power to one or more components of a power network includes a machine portion including a stator, a rotor and a rectifier, a battery connection terminal connected to the machine portion and configured to be connected to a battery, and an isolation device integral to the alternator. The isolation device is located on an electrical path between at least the machine portion and the battery connection terminal, and the isolation device is configured to isolate at least one of the alternator and another component of the power network from receiving electric current from the battery based on an undesirable condition occurring in the power network.

The present application discloses a flexible excitation system and a method for controlling the same. The flexible excitation system consists of a plurality of groups of flexible excitation power units connected in parallel, a deexcitation circuit unit and a flexible excitation control unit. The method for controlling the flexible excitation system includes: realizing the internal fault-tolerant operation control of the flexible excitation power units by cooperatively controlling AC circuit breakers and DC circuit breakers of the flexible excitation power units and a deexcitation switch; dynamically controlling ceiling voltage when terminal voltage drops by using the fast response control ability of the flexible excitation system, so as to improve the forced excitation output capacity of the self-shunt excitation system. Aiming at the possible overload problem of an excitation transformer during the operation of flexible excitation, an excitation transformer overload limiter for the flexible excitation system is provided to limit the operation state of the excitation transformer within an allowable overload operation range of equipment.

The present application discloses a flexible excitation system and a method for controlling the same. The flexible excitation system consists of a plurality of groups of flexible excitation power units connected in parallel, a deexcitation circuit unit and a flexible excitation control unit. The method for controlling the flexible excitation system includes: realizing the internal fault-tolerant operation control of the flexible excitation power units by cooperatively controlling AC circuit breakers and DC circuit breakers of the flexible excitation power units and a deexcitation switch; dynamically controlling ceiling voltage when terminal voltage drops by using the fast response control ability of the flexible excitation system, so as to improve the forced excitation output capacity of the self-shunt excitation system. Aiming at the possible overload problem of an excitation transformer during the operation of flexible excitation, an excitation transformer overload limiter for the flexible excitation system is provided to limit the operation state of the excitation transformer within an allowable overload operation range of equipment.

An auxiliary winding for use in an engine-driven generator system is disclosed. The auxiliary winding is separate from but resides with the main winding in the stator slots of an alternator in the generator system. The auxiliary winding is configured to utilize the fundamental component of the flux in the airgap of the alternator along with selected spatial harmonic components to provide power to an automatic voltage regulator during all operating conditions.