Abstract: A method of controlling connection of an AC power output to a load and power supply grid. The power output is produced by an AC power generating system which includes an AC/AC converter and is independently operable to supply power to the load. The converter is controlled in accordance with a reference generated within the system. To connect the power output to the power supply grid and to supply the load, the reference is replaced by another reference derived from the voltage of the grid, so that the converter is controlled by that other reference, when the power output is connected to the grid and supplies power required by the load. When the power output is disconnected from the grid or loss of the grid voltage occurs, the reference replaces the other reference, and the power generating system operates independently continuing to supply power required by the load without interruption.

Abstract: An electrical power supply system including an engine driven permanent magnet generator (11) operable to produce a variable voltage and high frequency output which is converted by a series train AC/AC conversion circuit (14) into a fixed voltage and relatively low frequency AC output for supply through a trip switch (56-58) to an external load (53-55). A bypass circuit including a pair of normally-closed parallel connected oppositely biased thyristors (66-68) is connected between the generator output and the output of the AC/AC conversion circuit (14).

Abstract: A method of and system for identifying the position of magnetic poles of a rotor of a multi-phase electrical machine relative to a stator of that machine is disclosed. The method includes the steps of applying a voltage pulse to stator windings of each phase, sensing current flow in the stator windings of each phase due to the application of the voltage pulse to the respective stator windings and determining the position of the magnetic poles of the rotor relative to the stator using the sensed current flow in the stator windings of each phase. The method is characterized in that the phases of the stator windings are star-connected at a neutral junction and the voltage pulse is applied to the stator windings of each phase in parallel.

Abstract: A method of controlling connection of an AC power output to a load (11) and to a power supply grid (8). The AC power output is produced by an AC power generating system which includes an AC/AC convertor (3) and which is independently operable to supply power to the load (11). Operation of the AC/AC convertor (3) for independent operation is controlled in accordance with a reference (Unr) which is generated within the system. In order to connect the AC power output to the power supply grid (8) in addition to supplying the load (11), the reference (Enr) which was derived from the AC power output voltage (Vacc) during independent operation is replaced by another reference (Irp) which is derived from the voltage (Vacg) of the grid (8) so that the AC/AC convertor (3) is controlled by that other reference (Irp) when the AC power output is connected.to the grid (8) as well as supplying the power required by the load (11).

Abstract: An electrical power supply system including an engine driven permanent magnet generator (11) operable to produce a variable voltage and high frequency output which is converted by a series train AC/AC conversion circuit (14) into a fixed voltage and relatively low frequency AC output for supply through a trip switch (56-58) to an external load (53-55). A bypass circuit including a pair of normally-closed parallel connected oppositely biased thyristors (66-68) is connected between the generator output and the output of the AC/AC conversion circuit (14).

Abstract: A method of and system for identifying the position of magnetic poles of a rotor of a multi-phase electrical machine relative to a stator of that machine is disclosed. The method includes the steps of applying a voltage pulse to stator windings of each phase, sensing current flow in the stator windings of each phase due to the application of the voltage pulse to the respective stator windings and determining the position of the magnetic poles of the rotor relative to the stator using the sensed current flow in the stator windings of each phase. The method is characterized in that the phases of the stator windings are star-connected at a neutral junction and the voltage pulse is applied to the stator windings of each phase in parallel.

Abstract: A generating set includes an engie driven generator (PGM) having two sets of stator windings (Ga and Gb). A bi-directional AC/DC converter (BCo) has its AC input connected to a junction between the two sets of stator windings (Ga and Gb) and its DC input connected to a number of the generator (PGM) is converted into an intermediate DC link by a convertor (Col) to produce an output for a load Lo. In normal operation of the system, an emf generated in one (Ga) of the sets of stator windings is rectified by the bi-direcitonal converter (BCo) to charge the energy storages (ESI-ESN) whilst the remainder of the generator output is fed through the converter to the load (Lo). In the event of a stepped increase in the load demand, the bi-directional converter (BCo) is operated to feed energy from the storage devices (ESI-ESN) to the stator windings (Ga) of the generator (PGM) to impart a driving torque to the generator rotor to accelerte the rotor to meet the increased load demand.

Abstract: A generating set includes an engie driven generator (PGM) having two sets of stator windings (Ga and Gb). A bi-directional AC/DC converter (BCo) has its AC input connected to a junction between the two sets of stator windings (Ga and Gb) and its DC input connected to a number of the generator (PGM) is converted into an intermediate DC link by a convertor (Col) to produce an output for a load Lo. In normal operation of the system, an emf generated in one (Ga) of the sets of stator windings is rectified by the bi-direcitonal converter (BCo) to charge the energy storages (ESI-ESN) whilst the remainder of the generator output is fed through the converter to the load (Lo). In the event of a stepped increase in the load demand, the bidirectional converter (BCo) is operated to feed energy from the storage devices (ESI-ESN) to the stator windings (Ga) of the generator (PGM) to impart a driving torque to the generator rotor to accelerte the rotor to meet the increased load demand.

Abstract: An electric power generating set which automatically varies its speed to match load variations at any time includes an engine driven generator G which provides a positive, Ga and a negative, Gb AC output voltage each of which is rectified by a respective rectifier Re3a, Re3b. Each rectifier Re3a,Re3b has one terminal connected to a common neutral line N. The DC output voltage of each rectifier Re3a, Re3b is boosted in a respective booster circuit which also has one terminal connected to the neutral line N. The combined output of the two booster circuits, Va+Vb is fed to an Inverter IN which converts it to the AC power output of the generating set. A DC load current between the booster circuits and the inverter IN is monitored and used to provide a speed demand feedback signal Srs to the speed control of the engine EN.

Abstract: An electric power generating set which automatically varies its speed to match load variations at any time includes an engine driven generator G which provides a positive, Ga and a negative, Gb AC output voltage each of which is rectified by a respective rectifier Re3a, Re3b. Each rectifier Re3a,Re3b has one terminal connected to a common neutral line N. The DC output voltage of each rectifier Re3a, Re3b is boosted in a respective booster circuit which also has one terminal connected to the neutral line N. The combined output of the two booster circuits, Va+Vb is fed to an Inverter IN which converts it to the AC power output of the generating set. A DC load current between the booster circuits and the inverter IN is monitored and used to provide a speed demand feedback signal Srs to the speed control of the engine EN.

Abstract: A hybrid generator set comprises an engine/generator or another controllable electrical source which provides a variable voltage electrical output, this output is rectified and fed to a DC to DC converter, the output (VDC) of which is monitored by a control circuit. This output serves as an intermediate DC output, which typically is used to power an inverter to generate an AC output which supplies an external load. The use of the DC to DC converter isolates the intermediate DC output from the generator output, and allows the generator set to operate efficiently over a wide engine/generator speed range, according to load demand.