Systems and methods for power generation using fuel cells

1. A fuel cell based power generation system, comprising: a fuel cell assembly configured to generate a DC power, the fuel cell assembly comprising a plurality of fuel cell units operatively coupled to one another;

at least one assembly switching element configured to operatively couple the fuel cell assembly to a first direct current (DC) bus;

at least one converter coupled between the first DC bus and an electrical grid;

a plurality of auxiliary loads operatively coupled to the first DC bus at a location between the at least one assembly switching element and the at least one converter,

wherein each fuel cell unit is configured to include a corresponding auxiliary load,

wherein the auxiliary loads are configured to heat the fuel cell assembly in a plurality of stages, and

wherein at least one of the plurality of auxiliary loads is configured to receive power from the fuel cell assembly via the at least one assembly switching element; and

a controller operatively coupled to the at least one converter, wherein the controller is configured to allow a voltage of the first DC bus to fluctuate within a range of voltage values.

2. The fuel cell based power generation system of claim 1 , wherein the at least one converter is configured to transfer electrical power between the electrical grid and at least one of the plurality of auxiliary loads and the fuel cell assembly.

3. The fuel cell based power generation system of claim 1 , further comprising a DC power source configured to provide power to at least some of the plurality of auxiliary loads during a startup of the fuel cell assembly.

4. The fuel cell based power generation system of claim 1 , wherein the at least one assembly switching element comprises a fuse, a relay, a manually operated switch, a mechanically operated switch, an electromechanically operated switch, a magnetically operated switch, or combinations thereof.

5. The fuel cell based power generation system of claim 1 , wherein each of the plurality of fuel cell units comprises a plurality of fuel cell subunits.

6. The fuel cell based power generation system of claim 5 , further comprising a plurality of subunit switching units, and wherein the plurality of subunit switching elements is configured to operatively couple the plurality of fuel cell subunits to one another.

7. The fuel cell based power generation system of claim 5 , wherein one or more fuel cell subunits of the plurality of fuel cell subunits are configured to receive at least one of a fresh fuel and an exhaust of other fuel cell subunits of the plurality of fuel cell subunits and the other fuel cell subunits of the plurality of fuel cell subunits are configured to receive the fresh fuel.

8. The fuel cell based power generation system of claim 1 , further comprising a second DC bus coupled between the plurality of auxiliary loads and the first DC bus via an auxiliary switching element.

9. The fuel cell based power generation system of claim 8 , wherein a voltage of the second DC bus is lower than a voltage of the first DC bus.

10. The fuel cell based power generation system of claim 1 , wherein the range of voltage values is in a range from about 345 volts to about 420 volts.

11. The fuel cell based power generation system of claim 1 , wherein the plurality of auxiliary loads comprises at least one of a fuel blower, an air blower, and an air ventilator.