Method and system for enhancing electrical power production by a power generation system by controlling switches to place a rotor-side converter in parallel with a line-side converter

1. A power generation system ( 100 , 200 , 300 , 400 ), comprising:

a prime mover ( 102 );

a doubly-fed induction generator (DFIG) ( 104 ) operatively coupled to the prime mover ( 102 ), wherein the DFIG ( 104 ) comprises a rotor winding ( 126 ) and a stator winding ( 122 );

a rotor-side converter ( 106 ) electrically connectible to the rotor winding ( 126 );

a line-side converter ( 108 ) elect: deafly connectible to a point of common coupling (PCC) ( 114 ), wherein the line-side converter ( 108 ) and the rotor-side converter ( 106 ) are coupled to each other via a direct current (DC) link;

a secondary power source ( 110 , 401 ) electrically coupled to the DC-link; and

a control sub-system comprising:

a plurality of switching elements ( 130 , and 132 or 201 ); and

a controller ( 136 ) operatively coupled to the plurality of switching elements ( 130 , and 132 or 201 ) and configured to selectively control switching of one or more switching elements of the plurality of switching elements ( 130 , and 132 or 201 ) based on a value of an operating parameter corresponding to at least one of the prime mover ( 102 ), the DIEM ( 104 ), or the secondary power source ( 110 , 401 ) to disconnect the rotor winding from the rotor-side converter and connect the rotor-side converter ( 106 ) in parallel with the line-side converter ( 108 ) at the PCC to increase an electrical power production by the power generation system ( 100 , 200 , 300 , 400 ).

2. The power generation system ( 100 , 200 , 300 , 400 ) as claimed in claim 1 , wherein the prime mover comprises a wind turbine and the operating parameter comprises a wind speed, an operating speed of the prime mover ( 102 ), an operating speed of a rotor ( 124 ) of the DFIG ( 104 ), an electrical power at the rotor winding ( 126 ), an electrical power at the stator winding ( 122 ), or combinations thereof.

3. The power generation system ( 100 , 200 , 300 , 400 ) as claimed in claim 1 , wherein the plurality of switching elements ( 130 , and 132 or 201 ) comprises a first switching element ( 130 ) and a second switching element ( 132 , 201 ), wherein:

the first switching element ( 130 ) is coupled between an interconnection terminal ( 138 ) and the PCC ( 114 ) and is switched to a conducting state by the controller to connect the rotor-side converter in parallel with the line-side converter at the PCC, and wherein the interconnection terminal ( 138 ) is located between the rotor-side converter ( 106 ) and the rotor winding ( 126 ); and

the second switching element ( 132 , 201 ) is coupled between the interconnection terminal ( 138 ) and the rotor winding ( 126 ) of the DFIG ( 104 ) and is switched to a non-conducting state by the controller to disconnect the rotor winding from the rotor-side converter.

4. The power generation system ( 200 ) as claimed in claim 3 , further comprising:

an energy storage device ( 202 ); and

an inverter ( 204 ) coupled to the energy storage device ( 202 ), wherein an input port ( 208 ) of the inverter ( 204 ) is coupled to the energy storage device ( 202 ) to receive a DC power from the energy storage device ( 202 ), and an output port ( 210 ) of the inverter ( 204 ) is coupled to the second switching element ( 132 , 201 ), wherein the second switching element ( 132 , 201 ) is a two-way switch.

5. The power generation system ( 200 ) as claimed in claim 4 , wherein the controller ( 136 ) is configured to facilitate electrical excitation of the rotor winding ( 126 ) from the energy storage device ( 202 ) by disconnecting the rotor-side converter ( 106 ) from the rotor winding ( 126 ) and connecting the rotor winding ( 126 ) to the output port ( 210 ) of the inverter ( 204 ) when the rotor-side converter ( 106 ) is connected in parallel with the line-side converter ( 108 ).

6. The power generation system ( 300 ) as claimed in claim 3 , further comprising an inverter ( 204 ), wherein an input port ( 208 ) of the inverter ( 204 ) is coupled to the DC-link ( 128 ) and an output port ( 210 ) of the inverter ( 204 ) is coupled to the second switching element ( 201 ), wherein the second switching element ( 201 ) is a two-way switch.

7. The power generation system ( 300 ) as claimed in claim 6 , wherein the controller ( 136 ) is configured to facilitate electrical excitation to the rotor winding ( 126 ) from the DC-link ( 128 ) by disconnecting the rotor-side converter ( 106 ) from the rotor winding ( 126 ) and connecting the rotor winding ( 126 ) to the output port ( 210 ) of the inverter ( 204 ) when the rotor-side converter ( 106 ) is connected in parallel to the line-side converter ( 108 ).

8. The power generation system ( 100 , 400 ) as claimed in claim 3 , further comprising a third switching element ( 134 ) coupled between the stator winding ( 122 ) of the DFIG ( 104 ) and the PCC ( 114 ),

wherein the controller ( 136 ) is configured to selectively control switching of the third switching element ( 134 ) to connect or disconnect the stator winding ( 122 ) from the PCC ( 114 ) based at least on the value of the operating parameter.