DC link variable speed constant frequency power source paralleling controls

A parallel power system comprising:

• at least two DC link variable speed, constant frequency power sources each having a Thevenin voltage and N output phases connected to a common bus;
• said power sources having substantially the same output frequency;
• means for monitoring error current flowing in at least N-1 of said output phases of each of said power sources;
• means for demodulating said error current to derive a real error current component and a reactive error current component;
• means for controlling the relative phase angle of the Thevenin voltages of said power sources in response to said real error current component, to reduce the magnitude of said real error current component;
• and
• means for controlling the relative magnitude of the Thevenin voltages of said power sources in response to said reactive error current component, to reduce the magnitude of said reactive error current component.

A method of controlling parallel connected DC link, variable speed, constant frequency multiple phase power sources, said method comprising the steps of:

• monitoring total real error current flowing in a plurality of output conductors of at least two, parallel connected constant frequency power sources, each having a Thevenin voltage;
• controlling the relative phase angle of the Thevenin voltages of said power sources in response to said total real error current, to reduce the magnitude of said total real error current;
• monitoring the reactive error current flowing in at least one of the output conductors of each of said parallel connected constant frequency power sources;
• and
• controlling the relative magnitude of the Thevenin voltages of said power sources in response to said reactive error current, to reduce the magnitude of said reactive error current.

A method of controlling parallel connected DC link, variable speed, constant frequency N-phase power sources, said method comprising the steps of:

• monitoring error current flowing in at least N-1 output conductors of at least two, parallel connected constant frequency power sources, each having a Thevenin voltage;
• demodulating said error current to derive a total real error current component and a reactive error current component;
• controlling the relative phase angle of the Thevenin voltages of said power sources in response to said total real error current component, to reduce the magnitude of said real error component;
• and
• controlling the relative magnitude of the Thevenin voltages of said power sources in response to said reactive error component, to reduce the magnitude of said reactive error component.

A parallel power system comprising:

• at least two DC link, variable speed, constant frequency power sources each having a Thevenin voltage and a plurality of output phases connected to a common bus;
• said power sources having substantially the same output frequency;
• means for monitoring total real error current flowing in said output phases of each of said power sources;
• means for monitoring reactive error current flowing in at least one of said output phases of each of said power sources;
• means for controlling the relative phase angle of the Thevenin voltages of said power sources in response to a combination of said total real error current and said reactive error current;
• and
• means for controlling the relative magnitude of the Thevenin voltages of said power sources in response to said reactive error current.

A parallel power system comprising;

• at least two DC link variable speed, constant frequency power sources each having a Thevenin voltage and N output phases connected to a common bus;
• said power sources having substantially the same output frequency;
• means for monitoring error current flowing in at least N-1 of said output phases of each of said power sources;
• means for demodulating said error current to derive a real error current component and a reactive error current component;
• means for controlling the relative phase angle of the Thevenin voltages of said power sources in response to a combination of said real error current component and said reactive error current component;
• and
• means for controlling the relative magnitude of the Thevenin voltages of said power sources in response to said reactive error current component.

A method of controlling parallel connected DC link, variable speed, constant frequency multiple phase power sources, said method comprising the steps of:

• monitoring total real error current flowing in a plurality of output conductors of at least two, parallel connected constant frequency power sources, each having a Thevenin voltage;
• monitoring the reactive error current flowing in at least one of the output conductors of each of said parallel connected constant frequency power sources;
• controlling the relative phase angle of the Thevenin voltages of said power sources in response to a combination of said total real error current and said reactive error current;
• and
• controlling the relative magnitude of the Thevenin voltages of said power sources in response to said reactive error current.

A method of controlling parallel connected DC link, variable speed, constant frequency N-phase power sources, said method comprising the steps of;

• monitoring error current flowing in at least N-1 output conductors of at least two, parallel connected constant frequency power sources, each having a Thevenin voltage;
• demodulating said error current to derive a total real error current component and a reactive error current component;
• controlling the relative phase angle of the Thevenin voltages of said power sources in response to a combination of said total real error current component and said reactive error current component;
• and
• controlling the relative magnitude of the Thevenin voltages of said power sources in response to said reactive error component, to reduce the magnitude of said reactive error component.