Power distribution and driving system for remotely underwater operated vehicle

1 . A power distribution and driving system for a remotely underwater operated vehicle ROV (ROV), comprises: a high-voltage DC power supply device, located above the water surface to provide a high-voltage DC voltage to the ROV, the high-voltage DC power supply device comprising: a voltage compensation module configured to: determine a voltage drop on a cable based on an output current of the high-voltage DC power supply device, and perform voltage drop compensation control based on the voltage drop and a target setting value of the ROV to output a stable high-voltage DC voltage; a DC buck conversion device, connected to the high-voltage DC power supply device through the cable; the DC buck conversion device being configured to: convert the high-voltage DC voltage to a low-voltage DC voltage to supply power to the ROV, wherein the DC buck conversion device comprises a plurality of parallel DC conversion modules, each DC conversion module equally bearing average load current to supply power to the ROV; and at least one thruster, the thruster comprising: a propeller, a synchronous motor, and a driver.

2 . The power distribution and driving system of claim 1 ,

wherein the high-voltage DC power supply device comprises:

a transformer,

a rectifier, and

a DC filter,

wherein the voltage compensation module is further configured to:

determine a voltage setting value at the rectifier end based on the target setting value and the voltage drop at the ROV, and

perform rectification control on the rectifier based on a deviation between the voltage setting value at the rectifier terminal and the output voltage of the high-voltage DC power supply device to output the stable high-voltage DC voltage.

3 . The power distribution and driving system of claim 1 , wherein the voltage compensation module is further configured to calculate the voltage drop on the cable based on the output current of the high-voltage DC power supply device and the characteristic parameters of the cable.

4 . The power distribution and driving system of claim 1 , wherein the plurality of DC conversion modules of the DC buck conversion device are respectively connected to the high-voltage DC input and low-voltage DC bus through corresponding input switches and output switches, and each DC conversion module exits power supply in case of its own failure.

5 . The power distribution and driving system of claim 1 ,

wherein the plurality of DC conversion modules of the DC buck conversion device are communicatively connected to each other, and each DC conversion module comprises:

a predetermined number p of Buck converters connected in series, and

a current-sharing and voltage-sharing controller,

wherein the current-sharing and voltage-sharing controller of each DC conversion module is further configured to:

determine a current-sharing control amount based on the output current values of all DC conversion modules and the voltage output value of the current DC conversion module,

determine p voltage-sharing control adjustment amounts based on voltage values and corresponding target reference values of the flyover capacitors of p−1 Buck converters from a low voltage end to a high voltage end of the current DC conversion module, and

perform flow control and voltage-sharing control on the current DC conversion module based on the current-sharing control amount and the p voltage-sharing control adjustment amounts.

6 . The power distribution and driving system of claim 5 , wherein

the current-sharing control amount and the p voltage-sharing control adjustment amounts are both duty cycle signals, and

the current-sharing and voltage-sharing controller of each DC conversion module is further configured to:

determine p comprehensive control amounts based on a sum of the current-sharing control amount and the p voltage-sharing control adjustment amounts, and

input the p comprehensive control amounts respectively and correspondingly into the switches of the p Buck converters of the current DC conversion module to perform current-sharing and voltage-sharing control.

7 . The power distribution and driving system of claim 1 , further comprising:

a standby energy storage unit coupled to a low-voltage DC bus through a DC-DC converter, wherein

the standby energy storage unit is charged by the DC buck conversion device through the DC-DC converter during normal operation of the cable, and

emergency power is supplied to the ROV through the DC-DC converter in case of cable failure.

8 . The power distribution and driving system of claim 1 , wherein

the synchronous motor comprises:

a permanent magnet synchronous motor, and

the thruster further comprises:

a magnetic gear that cooperates with the permanent magnet synchronous motor, the magnetic gear comprising:

a high-speed rotor,

an outer magnet rotor, and

a pole stator that magnetically couples the high-speed rotor to the outer magnet rotor,

the high-speed rotor of the magnetic gear is coupled to the rotor of the permanent magnet synchronous motor through an internal transmission shaft, and

the outer magnet rotor of the magnetic gear transmits power to the propeller through the external transmission shaft.

9 . The power distribution and driving system of claim 1 , comprising:

a plurality of the thrusters and a distribution controller for distributing propulsive force to the plurality of thrusters, the distribution controller determines an identification value of an external force and torque vector U(n+1) of the plurality of thrusters using an online identification algorithm:

U

^

(

n

+

1

)

=

[

b

^

1

,

1

b

^

1

,

2

…

b

^

1

,

m

b

^

2

,

1

b

^

2

,

2

…

b

^

2

,

m

⋮

⋮

⋱

⋮

b

^

6

,

1

b

^

6

,

2

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b

^

6

,

m

]

·

[

t

1

(

n

+

1

)

t

2

(

n

+

1

)

⋮

t

m

(

n

+

1

)

]

wherein n is the time factor index, T=[t 1 , t 2 , . . . , t m ] T is the thruster command vector, m is the number of thrusters, optimization is performed based on the Û(n+1) and the demanded value of the external force and torque vectors of each thruster U demand and the thruster command vector T=[t 1 , t 2 , . . . , t m ] T of each thruster to solve the thruster command:

min

⁢

c

1

·

(

U

demand

-

U

^

(

n

+

1

)

)

+

c

2

·

∑

i

=

1

m

(

t

i

(

n

+

1

)

-

t

_

(

n

+

1

)

)

2

s

.

t

.

t

j

,

min

≤

t

j

(

n

+

1

)

≤

t

j

,

max

,

j

∈

[

1

,

2

,

…

,

m

]

wherein c 1 and c 2 are weight parameters, t (n+1) is the average value of all current thrusters output, t j,min is the minimum propulsive force of the thruster, t j,max is the maximum propulsive force value.

10 . The power distribution and driving system of claim 9 ,

wherein the distribution controller performs a recursive least squares parameter identification algorithm with a forgetting factor on the linearized model V(n+1)=A·V(n)+B·T(n) of the ROV to obtain the identification value of the matrix

B

=

[

b

1

,

1

b

1

,

2

…

b

1

,

m

b

2

,

1

b

2

,

2

…

b

2

,

m

⋮

⋮

⋱

⋮

b

6

,

1

b

6

,

2

…

b

6

,

m

]

,

wherein V=[u,v,w,p,q,r] T , and u,v,w respectively represent the velocities of the ROV in the X, Y, and Z axis directions, p,q,r represent the pitch angular velocity, heading angular angle, and roll angular velocity of the ROV,

A

=

[

a

1

,

1

a

1

,

2

…

a

1

,

6

a

2

,

1

a

2

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2

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a

2

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6

⋮

⋮

⋱

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a

6

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1

a

6

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2

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a

6

,

6

]

,

B

=

[

b

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1

b

1

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2

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b

1

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m

b

2

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1

b

2

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2

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b

2

,

m

⋮

⋮

⋱

⋮

b

6

,

1

b

6

,

2

…

b

6

,

m

]

.