Application of ship electric propulsion
Electric propulsion is mostly used on ships with the following characteristics:
(1) Ships requiring high maneuverability;
(2) Ships with special nature of work are required;
(3) Ships with large-capacity auxiliary machinery;
(4) Military ships.
The use of electric propulsion on some of the following ships has particularly outstanding advantages, and there are application examples at home and abroad:
- a ferry
Electric propulsion is easy to be controlled centrally, and the ship can be directly controlled from the wheelhouse. After the electric propulsion is adopted, in addition to the propellers installed at the stern, lateral propellers can be conveniently installed at the bow and left and right, so that the ferry can navigate quickly, flexibly and safely in the main harbor and narrow waterways. Make the operation of docking and leaving the dock fast, accurate and reliable. “Yanda” is the first ro-ro passenger ship with full electric propulsion system in China. The ship was designed by Shanghai Ship Research and Design Institute and built by Tianjin Xingang Shipyard. It has a length of 182.6m, a width of 24.8m, and a full-load displacement. 16299t, service speed 18kn, [kn (kn) = 1 nautical mile/hour = (1852/3600) m/s.
] The wind resistance is level 8, and the propeller adopts ABB’s 2×4088kW compact Azipod propulsion device, which has been completed and put into use in 2006.
When the trailing suction dredger adopts electric propulsion, the dredging machinery (high-power mud pump) does not need to be driven by a special prime mover, and the power of the power unit can be allocated to trailing suction work and propulsion work at will. That is, when the trailing suction dredging, the ship sails at low speed, the main generator supplies a small part of the electric energy to the propulsion device, and most of the energy is supplied to the mud pump. When the trailing suction operation is not carried out, the ship can use all electric energy to sail at high speed, which improves the utilization rate of electric energy. This can reduce the number of prime movers, improve the economy of the power plant, simplify the cabin watch and maintenance work, increase ship productivity, and reduce dredging costs. For example, bucket chain dredgers often use the power of dredging machinery as propulsion power when they need to be self-propelled.
Electric propulsion can send out a large thrust at low speeds, which can accomplish the task of icebreaking well. Its locked-rotor feature prevents the unit from being overloaded, and there will be no accidents when the propeller is jammed by ice. The fast maneuverability and constant power automatic adjustment performance of the electric propulsion device also improve the working efficiency of the icebreaker.
- Crane ship
On a self-propelled crane ship, the electric power of the crane can be used as the propulsion power. For example, the 50t crane ship designed and manufactured by our country is equipped with two 55kW diesel generator sets to supply power to the crane during lifting operations. When sailing, power is supplied to two 55kW propulsion motors with a speed of about 3kn.
- Fishing vessel
According to the different requirements of various working conditions, the electric energy can be conveniently distributed to the propulsion, fishing and refrigeration machinery, so as to save some generator sets dedicated to auxiliary machines (such as trawlers and refrigerators), such as trawlers, looking for fish It only needs to operate under economic sailing conditions, and the propulsion device consumes part of the electric energy. In trawling fishing, in addition to part of the electric energy for low-speed propulsion, the rest can be supplied to trawling machinery and other equipment. It can supply all the electric energy to the propulsion device and return to home at full speed.
The electric propulsion device has a wide range of speed regulation, so it can guarantee the full power from the free navigation state to the towing state, and obtain the best efficiency of the towing work. In addition, when the towing is too heavy, the rotor can be blocked to avoid accidents. Since electric propulsion can be conveniently controlled in the cab, the correctness of operation and the safety of towing are ensured. It is more suitable for port tugboats.
- Survey ship, survey ship
The deck machinery, ancillary equipment and scientific research instruments on these ships often require a large amount of electrical energy, and they can obtain electrical energy from the main generator set together with the electric propulsion device. Electric propulsion has high maneuverability, low-speed navigation characteristics, etc., which are indispensable for survey ships and survey ships with variable navigation conditions and complex navigation areas.
- Fire boat
When the firefighting boat is rushing to the fire site, it must use all the power of the main generator for propulsion. After reaching the fire site, it only needs to supply a small amount of electric energy for low-speed propulsion, and slowly travel around the fire site, while most of the electric energy is supplied to the fire pump. Electric propulsion can not only reduce the number of prime movers on the firefighting ship, but also can be centrally controlled in the bridge to obtain good maneuverability and maneuverability, so that the firefighting ship is in the best position for firefighting and completes the firefighting task.
- Salvage boat
Similar to the firefighting ship, after rushing to the rescue site, rescue and salvage equipment (such as air compressors, winches, etc.) can obtain a large amount of electricity from the main generator set.
- Pilot boat
Electric propulsion can accurately control the low-speed propulsion to keep the position of the ship unchanged. When moving in harsh weather conditions, electric propulsion can also increase its safety. Since the work of the pilot boat includes a long period of low-speed sailing, after adopting electric propulsion, only a part of the crew can be operated, which reduces fuel consumption and improves economy; with a certain fuel reserve, the number of times to add fuel to the return flight is reduced. Increased operating time.
11 Rope boat
When laying cables, a stable and correct heading and low-speed propulsion with a large adjustment range are required. The use of electric propulsion can meet the above requirements, and at the same time, it can also reduce the propulsion speed and use the surplus power for cabling operations.
- Navigation mark work boat
When laying and maintaining navigation aids, low-speed electric propulsion is required to make ships gradually approach and maintain the position where navigation aids are laid. Most of my country’s coastal navigation mark ships use electric propulsion.
- Vessels for underwater operations
Because it is impossible to use diesel engines and other prime movers that require oxygen under water, the underwater operating vessels usually use battery-powered electric propulsion methods, such as submarines and submersibles.
- Large cruise
The electric motor propelled by the frequency converter directly controls the driving device, which makes the layout of the cruise ship convenient and compact; increases the passenger ship room, reduces noise, and makes the life of passengers more comfortable. Such as the US “Fantasy”, Japan’s “Crystal Harmonuy” and so on.
- Modern military ships
On the one hand, modern military ships require strong maneuverability. On the other hand, they are also equipped with high-energy weapons such as electromagnetic guns, lasers, and microwaves, and high-energy equipment such as electromagnetic catapults. After adopting electric propulsion, the ship’s propulsion is driven by an electric motor, which is flexible in control and convenient in speed adjustment. When the ship is sailing at low speed, a large amount of energy can be used for high-energy weapons and high-energy equipment. For example, the Type 45 destroyer built by the United Kingdom and the DDX destroyer developed by the United States all use electric propulsion.