Techniques and methods related to a multi-mode operation of a synchronous electrical generator. The synchronous generator is configurable in at least two modes: a grid-power mode and a power-generation mode. In the power-generation mode, electrical power is generated in response to power produced by a prime mover. In the grid-power mode, the rotor is in standstill mode, and the configurable rotor winding is configured to generate a plurality of AC magnetic fields. The system provides for seamless transfer of power between grid-power to power generation using an energy storage unit and associated power conditioning apparatus.

There is described a method and system for starting at least one engine from a twin engine installation having a first engine arrangement and a second engine arrangement. The method comprises receiving a first voltage level from a power source and increasing the first voltage level to a second voltage level; charging an energy storage unit having at least a first super-capacitor and a second super-capacitor to the second voltage level; selectively connecting one of the first super-capacitor and the second super-capacitor to a first power control unit in the first engine arrangement; controlling a discharge current to a first electric machine in the first engine arrangement via the first power control unit; and rotating a rotor of the first electric machine to an above engine idle speed to start a first engine of the twin engine installation.

There is described a method and system for starting at least one engine from a twin engine installation having a first engine arrangement and a second engine arrangement. The method comprises receiving a first voltage level from a power source and increasing the first voltage level to a second voltage level; charging an energy storage unit having at least a first super-capacitor and a second super-capacitor to the second voltage level; selectively connecting one of the first super-capacitor and the second super-capacitor to a first power control unit in the first engine arrangement; controlling a discharge current to a first electric machine in the first engine arrangement via the first power control unit; and rotating a rotor of the first electric machine to an above engine idle speed to start a first engine of the twin engine installation.

An engine generator detects a DC voltage in a path from a rectifier to an inverter in controlling charge/discharge, and makes a duty ratio in switching control of a charging conductor of a power storage device higher than a duty ratio in the switching control of a discharging conductor of the power storage device when the DC voltage is higher than a target voltage of the DC voltage, and makes the duty ratio in the switching control of the discharging conductor of the power storage device higher than the duty ratio in the switching control of the charging conductor of the power storage device when the DC voltage is lower than the target voltage.

An engine generator detects a DC voltage in a path from a rectifier to an inverter in controlling charge/discharge, and makes a duty ratio in switching control of a charging conductor of a power storage device higher than a duty ratio in the switching control of a discharging conductor of the power storage device when the DC voltage is higher than a target voltage of the DC voltage, and makes the duty ratio in the switching control of the discharging conductor of the power storage device higher than the duty ratio in the switching control of the charging conductor of the power storage device when the DC voltage is lower than the target voltage.

In a control apparatus mounted in a vehicle supporting start-stop control, for controlling a power supply system, a target charge level setter variably sets a target charge level of a second rechargeable battery when an internal-combustion engine of the vehicle is operating. The target charge level setter sets the target charge level to a higher level as load current increases, and when setting the target charge level, performs at least one of subtracting a first load quantity indicative of a current that is supplied to first electrical loads from a detected value of the load current and adding a second load quantity indicative of a current that is supplied to second electrical loads to the detected value of the load current. The first electrical loads operate when the internal-combustion engine is operating, and the second electrical loads operate when the engine is not operating.

An electric power generation system and a method in an electric power generation system. The system comprising one or more generators for producing electrical energy, each generator being arranged to be driven with a corresponding prime mover, wherein the generators are multiphase AC generators adapted to generate a multiphase voltage having a frequency and an amplitude, the phase outputs of the generators are connectable to a common multiphase bus for distributing the electrical energy generated by the AC generators, the system comprises further means for providing independent reference values for a rotational speed of the prime movers and for amplitude of the multiphase voltage, the rotational speed of the prime movers defining the frequency of the multiphase voltage, and the system is adapted to operate in at least three operation points on the basis of the provided independent reference values, an operation point being defined by a ratio of the amplitude of the multiphase voltage to the frequency of the multiphase voltage, wherein the at least three operation points are different.

An electric power generation system and a method in an electric power generation system. The system comprising one or more generators for producing electrical energy, each generator being arranged to be driven with a corresponding prime mover, wherein the generators are multiphase AC generators adapted to generate a multiphase voltage having a frequency and an amplitude, the phase outputs of the generators are connectable to a common multiphase bus for distributing the electrical energy generated by the AC generators, the system comprises further means for providing independent reference values for a rotational speed of the prime movers and for amplitude of the multiphase voltage, the rotational speed of the prime movers defining the frequency of the multiphase voltage, and the system is adapted to operate in at least three operation points on the basis of the provided independent reference values, an operation point being defined by a ratio of the amplitude of the multiphase voltage to the frequency of the multiphase voltage, wherein the at least three operation points are different.

An alternator voltage may be controlled based on a proportional gain scheduling in response to an engine load of an internal combustion engine and/or a state of charge (SOC) deviation for a battery based on a target SOC of the battery and an actual SOC of the battery. The alternator voltage may be a voltage less than a current battery voltage under high engine loads to enable the battery to power an accessory system and the alternator voltage may be a voltage greater than a voltage of the battery under low engine loads or engine loads less than high engine loads to enable the alternator to charge the battery.

In accordance with one or more embodiments, a method for implementing a PMG variable speed constant frequency generating system on an aircraft including an aircraft engine is provided. The method includes receiving AC power from a PMG at an AC/DC conversion stage, the received power being proportional to a rate of rotation of the aircraft engine and converting the AC power to DC power in the AC/DC conversion stage. The method further includes sensing a DC voltage output by the AC/DC conversion stage and providing the DC voltage to a DC/AC conversion stage. The method includes providing a control signal to the DC/AC conversion stage to control a frequency and a voltage of an output signal of the DC/AC conversion stage without varying an electrical signal provided to the PMG.