Conditionally regulated hybrid electric HVDC architecture

1 . A method comprising: determining an operating mode of a hybrid electric propulsion system including a conditionally regulated high voltage direct current (HVDC) architecture, the conditionally regulated HVDC architecture including: a first switchable circuit formed between an HVDC bus, an HVDC electrical source, and a bi-directional direct current to direct current (DC-DC) converter configured to regulate electrical power flowing between the HVDC bus and the HVDC electrical source; and a second switchable circuit formed between the HVDC bus and the HVDC electrical source; and configuring the conditionally regulated HVDC architecture based on the determined operating mode, wherein, after switching the HVDC electrical source into the second switchable circuit, unregulated electrical power flows from the HVDC electrical source to a motor/generator electrically coupled to the HVDC bus.

2 . The method of claim 1 , wherein:

the operating mode is determined to be a motoring mode; and

configuring the conditionally regulated HVDC architecture comprises:

switching the DC-DC converter out of the first switchable circuit such that electrical power is unable to flow between the HVDC bus and the DC-DC converter; and

switching the HVDC electrical source into the second switchable circuit such that unregulated electrical power is able to flow from the HVDC electrical source to the HVDC bus.

3 . The method of claim 1 , wherein:

the operating mode is determined to be a generation mode; and

configuring the conditionally regulated HVDC architecture comprises:

switching the DC-DC converter into the first switchable circuit such that electrical power regulated by the DC-DC converter flows between the HVDC electrical source and the HVDC bus; and

switching the HVDC electrical source out of the second switchable circuit such that unregulated electrical power is unable to flow between the HVDC electrical source and the HVDC bus.

4 . The method of claim 3 , wherein, after switching the DC-DC converter into the first switchable circuit, the HVDC electrical source receives power regulated by the DC-DC converter from the motor/generator electrically coupled to the HVDC bus.

5 . The method of claim 1 , wherein:

the operating mode is determined to be a pre-charge mode; and

configuring the conditionally regulated HVDC architecture comprises:

switching the DC-DC converter into the first switchable circuit such that an electrical voltage of the HVDC bus matches an electrical voltage of the HVDC electrical source regulated by the DC-DC converter; and

after the electrical voltage of the HVDC bus matches the electrical voltage of the HVDC electrical source regulated by the DC-DC converter:

switching the HVDC electrical source into the second switchable circuit such that unregulated electrical power flows from the HVDC electrical source to the HVDC bus; and

switching the DC-DC converter out of the first switchable circuit such that electrical power is unable to flow between the HVDC bus and the DC-DC converter.

6 . The method of claim 5 , wherein, after switching the HVDC electrical source into the second switchable circuit, unregulated electrical power flows from the HVDC electrical source to the motor/generator electrically coupled to the HVDC bus.

7 . An apparatus comprising: at least one processor configured to: determine an operating mode of a hybrid electric propulsion system including a conditionally regulated high voltage direct current (HVDC) architecture, the conditionally regulated HVDC architecture including: a first switchable circuit formed between an HVDC bus, an HVDC electrical source, and a bi-directional direct current to direct current (DC-DC) converter configured to regulate electrical power flowing between the HVDC bus and the HVDC electrical source; and a second switchable circuit formed between the HVDC bus and the HVDC electrical source; and configure the conditionally regulated HVDC architecture based on the determined operating mode, wherein, when the HVDC electrical source is switched into the second switchable circuit, unregulated electrical power is able to flow from the HVDC electrical source to a motor/generator electrically coupled to the HVDC bus.

8 . The apparatus of claim 7 , wherein, to configure the conditionally regulated HVDC architecture when the operating mode is determined to be a motoring mode, the at least one processor is configured to:

switch the DC-DC converter out of the first switchable circuit such that electrical power is unable to flow between the HVDC bus and the DC-DC converter; and

switch the HVDC electrical source into the second switchable circuit such that unregulated electrical power is able to flow from the HVDC electrical source to the HVDC bus.

9 . The apparatus of claim 7 , wherein, to configure the conditionally regulated HVDC architecture when the operating mode is determined to be a generation mode, the at least one processor is configured to:

switch the DC-DC converter into the first switchable circuit such that electrical power regulated by the DC-DC converter is able to flow between the HVDC electrical source and the HVDC bus; and

switch the HVDC electrical source out of the second switchable circuit such that unregulated electrical power is unable to flow between the HVDC electrical source and the HVDC bus,

wherein, when the DC-DC converter is switched into the first switchable circuit, the HVDC electrical source is able to receive power regulated by the DC-DC converter from the motor/generator electrically coupled to the HVDC bus.

10 . The apparatus of claim 7 , wherein, to configure the conditionally regulated HVDC architecture when the operating mode is determined to be a pre-charge mode, the at least one processor is configured to:

switch the DC-DC converter into the first switchable circuit such that an electrical voltage of the HVDC bus matches an electrical voltage of the HVDC electrical source regulated by the DC-DC converter; and

after the electrical voltage of the HVDC bus matches with the electrical voltage of the HVDC electrical source regulated by the DC-DC converter:

switch the HVDC electrical source into the second switchable circuit such that unregulated electrical power is able to flow from the HVDC electrical source to the HVDC bus; and

switch the DC-DC converter out of the second switchable circuit such that electrical power is unable to flow between the HVDC bus and the DC-DC converter.

11 . The apparatus of claim 10 , wherein, when the HVDC electrical source is switched into the second switchable circuit, unregulated electrical power is able to flow from the HVDC electrical source to the motor/generator electrically coupled to the HVDC bus.

12 . The apparatus of claim 7 , wherein the at least one processor is configured to switch between the HVDC bus and a low voltage DC bus.

13 . A system comprising:

an engine;

at least one motor/generator configured to:

provide mechanical power to the engine during a motoring mode; and

generate electricity from mechanical power provided by the engine during a generation mode;

a conditionally regulated high voltage direct current (HVDC) architecture electrically coupled to an input/output of the at least one motor/generator, the conditionally regulated HVDC architecture including:

a first switchable circuit formed between an HVDC bus, an HVDC electrical source, and a bi-directional direct current to direct current (DC-DC) converter configured to regulate electrical power flowing between the HVDC bus and the HVDC electrical source; and

a second switchable circuit formed between the HVDC bus and the HVDC electrical source; and

a controller configured to:

determine an operating mode of the system; and

configure the conditionally regulated HVDC architecture based on the determined operating mode,

wherein:

when the HVDC electrical source is switched into the second switchable circuit, unregulated electrical power is able to flow from the HVDC electrical source to the at least one motor/generator via the HVDC bus; and

the system further comprises a charging protection circuit configured to prevent flow of electrical power from the HVDC bus to the HVDC electrical source.

14 . The system of claim 13 , wherein, to configure the conditionally regulated HVDC architecture when the operating mode is determined to be a motoring mode, the controller is configured to:

switch the DC-DC converter out of the first switchable circuit such that electrical power is unable to flow between the HVDC bus and the DC-DC converter; and

switch the HVDC electrical source into the second switchable circuit such that unregulated electrical power is able to flow from the HVDC electrical source to the HVDC bus.

15 . The system of claim 13 , wherein, to configure the conditionally regulated HVDC architecture when the operating mode is determined to be a generation mode, the controller is configured to:

switch the DC-DC converter into the first switchable circuit such that electrical power regulated by the DC-DC converter is able to flow between the HVDC electrical source and the HVDC bus; and

switch the HVDC electrical source out of the second switchable circuit such that unregulated electrical power is unable to flow between the HVDC electrical source and the HVDC bus.

16 . The system of claim 15 , wherein, when the DC-DC converter is switched into the first switchable circuit, the HVDC electrical source is able to receive power regulated by the DC-DC converter from the at least one motor/generator via the HVDC bus.

17 . The system of claim 13 , whereinto configure the conditionally regulated HVDC architecture when the operating mode is determined to be a pre-charge mode, the controller is configured to:

switch the DC-DC converter into the first switchable circuit such that an electrical voltage of the HVDC bus matches an electrical voltage of the HVDC electrical source regulated by the DC-DC converter; and

after the electrical voltage of the HVDC bus matches with the electrical voltage of the HVDC electrical source regulated by the DC-DC converter:

switch the HVDC electrical source into the second switchable circuit such that unregulated electrical power is able to flow from the HVDC electrical source to the HVDC bus; and

switch the DC-DC converter out of the second switchable circuit such that electrical power is unable to flow between the HVDC bus and the DC-DC converter; and

when the HVDC electrical source is switched into the second switchable circuit, unregulated electrical power is able to flow from the HVDC electrical source to the at least one motor/generator.