RU2522733C1 - Electric propulsion ship system with two-screw propulsion unit with ring structure engines - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: electric propulsion ship system contains switchboard buses connected via circuit breaker and reactance to reversible frequency converter. Two propelling motors are connected respectively to frequency converter with two separate output power circuits. Propelling motors with permanent-magnet excitation have ring structure. Fixed pitch propellers are installed in rotor pockets of each motor. Blades of the first propeller are made with opposite turn to blades of the second propeller. Frequency converter contains controlled input rectifier whose power output is connected with condenser-type accumulator of direct current section, voltage sensor of direct current section with power inputs of two inverters, as well as two frequency setting device. Frequency converter components control is executed using local control system.

EFFECT: higher coefficient of efficiency, lower energy losses, lower level of noise and vibrations.

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Description

The invention relates to the field of shipbuilding, in particular to ship electrical propulsion systems with frequency converters and propeller motors. Various converters with uncontrolled rectifiers, which have high energy performance and reliability, are widely used as converters, and electric motors of direct and alternating current installed in the ship’s hull or in the gondola of the “rotary column” type propeller with a rotor having a shaft for propeller installation.

Known ship propulsion system of the type "rotary column" [RF patent No. 2119875 publ. 10/10/1998]. The installation contains a rotational rotational motor enclosed in a streamlined casing (nacelle) and two propellers rotating in opposite directions, namely a counter-propeller mounted on the rotor shaft of the biotational engine, and a propeller mounted on the hollow shaft of the rotating stator, the coaxial rotor shaft. The casing is mounted to rotate in a horizontal plane. Unfortunately, the control circuit in RF patent No. 21919875 is not disclosed, however, for a specialist it is obvious that the rotary column is part of the ship’s electric propulsion system, and the propeller of the installation is connected to a static frequency converter, which, in turn, is connected to the power system and to the electric generator driven into rotation by a heat engine. The disadvantages of the analogue include:

- increased mass, dimensions and energy losses due to the large hydrodynamic resistance of the nacelle with a propeller motor installed in it and uncompensated (residual) "twisting" of the attached masses of water;

- reduced level of vibro-acoustic characteristics of the propulsion system;

- increased levels of electromagnetic interference and harmonic components in the current consumed by standard frequency converters from the ship network;

- reduced reliability of the design of the bi-rotational engine and increased losses.

More progressive and with better vibroacoustic characteristics are motor-propulsion systems with magnetic ring-shaped motors. The ship’s electric propulsion system based on a propulsion system with a ring-shaped engine (hereinafter referred to as DDS KK) was selected as a prototype [A. Grigoryev. A new generation shipboard electric propulsion system, “Marine Fleet” No. 02 (1500), 2012, pp. 38-40]. The ship’s electric propulsion system comprises a propulsion system in the form of a submersible electric motor of a ring design combined with a propeller. The stator windings of the electric motor are connected through a reversible frequency converter, inductor and circuit breaker to the switchboard. The frequency converter consists of a series-connected active rectifier and inverter. The input of the active rectifier is connected to the aforementioned inductor, and the output of the frequency converter (inverter output) is connected to the stator windings of a submersible electric motor of a ring design.

The disadvantages of this prototype include:

- reduced level of vibro-acoustic characteristics of the propulsion system;

- The efficiency of the propulsion due to energy losses due to the "twisting" of the attached masses of water.

The problem solved by the invention is the expansion of the arsenal of means and the creation of a new ship’s electric propulsion system with a propulsion system based on a twin-screw module of a ring design with increased energy efficiency, economy, reduction of noise and vibration created by the operation of the propulsion system, which allows, by minimizing hydrodynamic losses and creating additional emphasis efforts to provide an increase in the efficiency of the propulsion device, to increase the vibration-acoustic characteristics, with the achievement of economy and efficiency efficient use of energy, as well as an additional opportunity to use more technologically advanced and efficient propeller-type propellers.

Achievable technical result is to enable:

- increase the propulsion efficiency;

- reduction of energy losses due to the control of electric motors according to the characteristic obtained experimentally;

- additional reduction of energy losses due to the small hydrodynamic resistance of the module with two rowing synchronous synchronous electric motors of a ring design with excitation from permanent magnets;

- reduction of noise and vibration generated by the module, due to the control of electric motors according to the characteristic obtained experimentally;

- an additional increase in the efficiency of the installation and a decrease in the level of vibro-acoustic disturbances due to the use of two impeller-type propellers in the module and an increase in the quality and efficiency of energy use by the frequency converter, which provides filtering, reactive power compensation and phase voltage balancing in the input circuit, output voltage stabilization and the ability to energy recovery for use by ship consumers.

The complex task posed is solved by changing the functional diagram of the installation and changing the design.

The inventive marine electric propulsion system with a twin-screw propulsion module incorporates distribution board buses connected through a circuit breaker and inductor to a reversible frequency converter. The first output of the frequency converter is connected to the stator winding of the first rowing electric motor of a ring design with excitation from permanent magnets (hereinafter - the first electric motor). A first fixed pitch propeller is installed in the rotor cavity of the first electric motor. It differs from the prototype in that it additionally contains a second rowing electric motor of a ring design with excitation from permanent magnets (hereinafter - the second electric motor). Its stator winding is connected to the second output of the frequency converter. A second fixed pitch propeller is installed in the rotor cavity of the second electric motor, both of the aforementioned electric motors are aligned and combined into a single module so that their cavities form a through channel. The blades of the first propeller are made with an opposite direction to the blades of the second propeller. The mentioned frequency converter contains a controlled rectifier installed at the input, the power output of which is connected to a capacitor drive of the DC link, with a voltage sensor on the capacitor drive and with the power inputs of two inverters that are part of the frequency converter. The converter also contains two adjusters of the rotational speeds of the electric motors, each of the adjusters with its first output connected to the control input of one of the inverters, and its second output connected to the first output of the other adjuster.

The ship’s electric propulsion system incorporates a local control system connected to the control input of the controlled rectifier, with the signal output of the voltage sensor on the capacitor bank, with the control inputs of the frequency adjusters, and also with the signal outputs of the first and second phase current sensors, the first and second voltage sensors phases installed in the output power circuits of inverters, which are the outputs of the frequency converter. The motors are connected with the possibility of multidirectional rotation of their rotors.

Figure 1 presents a diagram of a ship's electric propulsion system with a twin-screw propulsion module with ring-shaped engines, Figure 2 is a design of the propulsion module, Figure 3 is a view A-A of Figure 2. The following notation is introduced in the Figures:

1 - busbar switchboard; 2 - circuit breaker; 3 - throttle; 4 - frequency converter; 5, 6 - the first and second, respectively, rowing synchronous electric motors of a ring design with excitation from permanent magnets, 7 - the first propeller of a fixed pitch; 8 - second propeller fixed pitch; 9 - motor-propulsion module; 10, 11 - cavity of the first and second rotors, respectively; 12, 13 - the first and second rotors, respectively; 14 - through channel; 15 - controlled rectifier with vector control; 16 - capacitor bank; 17 - voltage sensor on a capacitor bank; 18 - the first inverter; 19 - second inverter; 20 - local control system; 21 - the first speed controller of electric motors; 22 - a second adjuster of the rotational speeds of the electric motors, 23 and 24 - the first and second phase current sensors, 25 and 26 - the first and second phase voltage sensors; 27 and 28 - stators of propeller motors, 29 - interface. A ship’s electric propulsion system with a twin-screw motor-propulsion module based on ring motors contains switchboard buses 1 connected through a circuit breaker 2 and a choke 3 to a frequency converter 4. Two synchronous motors 5 are connected respectively to a frequency converter 4 with two separate output three-phase circuits 5 and 6 (their stator windings). Permanent magnet driven rowing motors have an annular structure, similar to that described in the prior art. In the rotor cavity of each of the electric motors, fixed-pitch propellers 7 and 8 are installed. Structurally, both electric motors 5 and 6 are designed as a module 9 of the propulsion system, that is, they have a common housing where they are coaxial, and the cavities 10 and 11 of their rotors 12 and 13 in the housing of the module 9 form a through channel 14. The blades of the first propeller 7 are made with an anti-directional turn to the blades of the second propeller 8. The frequency converter 4 is made reversible and contains a controlled rectifier 15 with vector control, the power output of which is connected to a capacitor drive 16 of the DC link, with a voltage sensor 17 on the capacitor bank and the power inputs of the inverters 18 and 19. The controlled rectifier 15 is connected by the control input to the local control system 20. As part of the frequency converter 4, there is also a first drive 21 of the frequency of rotation of the electric motors 5 and 6 in the function of obtaining the maximum total stop of the propellers and a second adjuster 22 of the rotational speeds of the electric motors as a function of the minimum noise and vibration reproduced by the module, connected by their inputs to the local control system 20. The first output the first master 21 is connected to the first output of the second master 22 and with the control input of the first inverter 18, and the second output of the first master 21 is connected with the second output of the second master 22 and with the control input of the second inverter 19. The output power circuits of inverters 18 and 19 through the power circuits of the corresponding sensors 23 and 24 of the phase current, which are the outputs of the Converter 4 and to which the first and second sensors 25 and 26 of the phase voltages are connected, are connected to the windings of the stators 27 and 28 of the corresponding rowing motors 5 and 6 of the ring design and. The electric motors are connected with the opposite phase rotation for the multidirectional rotation of their rotors 12 and 13 with built-in propellers 7 and 8 and creating an emphasis in one common direction. The signal outputs of the voltage sensors 17, 25, 26 and current sensors 23 and 24 are connected to a local control system 20, to which an interface 29 is connected to connect to the upper level system.

The ship’s electric propulsion system with a twin-screw propulsion module based on ring-shaped engines works as follows.

The operation of the installation is controlled by the upper-level system, transmitting commands through the interface 29 to the local control system 20, which sets the operating modes for the controlled rectifier 15 and inverters 18 and 19, controlling the voltage on the capacitor bank 16 using the voltage sensor 17 and the currents of the stators 27 and 28, corresponding to mechanical load moments of electric motors 5 and 6 and the efforts of the stops created by the propellers 7 and 8. The operation of power circuits of a controlled rectifier 15 with vector control and inverters 18 and 19 is controlled by built-in controllers according to the information of their own sensors (not shown in the figures).

By the signal received at the input of the local control system 20 via the interface 29 from the upper level control system, the electric movement system can be transferred to the following main operating modes:

- driving and braking mode with maximum stop force;

- mode of movement and braking with a minimum of noise and vibration created by the propulsion module;

- modes of movement and braking with reactive power compensation generated by ship electrical consumers and balancing modulo and phase voltage on the busbars 1 of the switchboard.

The vessel is propelled by electric motors 5 and 6 of module 9, powered by inverters 18 and 19 in the form of three-phase voltage systems that differ in frequency and amplitude, with opposite phase rotation, which provides multidirectional rotation of the propellers 7 and 8 with the opposite direction of rotation of the blades to create emphasis in one general direction. The voltage from the busbars 1 of the switchboard through the circuit breaker 2, the inductor 3 is supplied to the controlled rectifier 15, to the inverters 18 and 19. The controlled rectifier 15 provides stabilization of the DC voltage on the capacitor storage 16 DC link, filtering the current consumption, changing the angle of shift between the voltage and current in each phase at its input according to the instructions of the local control system 20 for reactive power compensation and for balancing the three-phase system modulo and phase we vectors of supply voltages. Inverters 18 and 19 control the operation of electric motors 5 and 6 in accordance with the principle of vector control of an electric drive.

When braking, the electric motors 5 and 6 are transferred to the generator mode, in which electric energy is supplied through inverters 18 and 19, a controlled rectifier 15, a choke 3, an automatic switch 2 to the distribution busbars 1, from where it is supplied to power marine electrical consumers (not shown in the figure) . The excess electricity is absorbed by the braking resistor installed in the DC link of the controlled rectifier 15 (not shown in the figures).

Modes of movement and braking with maximization of the total stop effort at optimal energy consumption are achieved by controlling the electric motors taking into account the design features and hydrodynamic characteristics of module 9 and propellers 7 and 8. The stop force of module 9 is the sum of the stop forces of the propellers 7 and 8, which are rotated electric motors 5 and 6. Optimum dependences of the stop forces on the rotational speed of each propeller, when they work together in module 9 and the minimum total energy consumption on the movement of the vessel obtained experimentally. The electric power supplied to the electric motors 5 and 6 is converted into mechanical power with rotor speeds corresponding to the resistance moments of the propellers 7 and 8. The characteristic stored in the memory of the first setter 21 sets its rotation frequency for each electric motor, the optimal distribution coefficient of electric power, fed to electric motors 5 and 6 to obtain the maximum total stop force from the propellers of module 9.

The upper level system through the local control system 20 sets the value corresponding to the thrust of the module 9 to the first speed controller 21, which distributes the tasks according to the output power to inverters 18 and 19. Inverters 18 and 19 generate output voltages in frequency and amplitude to power the windings stators of electric motors 5 and 6. Electric power is converted into the mechanical rotation power of each propeller, into the total stop force of the module, which sets the vessel in motion at the corresponding speed.

The mode of movement and braking with a minimum of noise and vibration associated with the hydrodynamics of the design of the housing of the propulsion module 9, propellers 7 and 8, is carried out by increasing the laminarity of the water flow at the output of the module, as well as optimizing its operation modes. According to the signals of the upper-level control system and the local control system 20, the second setter 22 sets the optimal electric power distribution coefficient for the propeller motors 5 and 6 over the entire range of rotational speeds of the propellers 7 and 8, with a minimum level of noise and vibration reproduced by module 9, according to the characteristic obtained experimentally. The sets 21 and 22 set the frequency and amplitude of the output voltages inverters 18 and 19 supplying the windings of the stators 27 and 28 of the electric motors 5 and 6. The system 20 monitors the set parameters, calculates the values of the rotational speeds, power consumed by the electric motors, and the thrust force according to the characteristics of the propellers using information from the sensors 23, 24 current and 25, 26 phase voltage. The use in the design of module 9 of the propeller motors 5 and 6 of a ring structure with excitation from permanent magnets having minimal dimensions of the end part, minimizes the hydrodynamic resistance and better streamlining of the housing.

The noise level reproduced by the equipment of the electric propulsion system, especially generators, propeller motors 5 and 6, electric consumers, depends on the amount of currents consumed by them, which can contain reactive and higher harmonic components, as well as on the symmetry of three-phase voltage supply systems.

In the mode of movement and braking with reactive power compensation generated by ship electrical consumers, at the command of the upper level system, the local control system 20 generates a reference signal, according to which the controlled rectifier 15 changes the shift angle between the voltage and phase current vectors necessary to compensate the reactive power on the tires 1 power distribution box for consumers. The average voltage at the output of the controlled rectifier 15 remains stable and the inverters 18 and 19 perform the function specified by the control system 20.

The mode of movement and braking with balancing by the modulus and phase of the voltage on the buses 1 of the power distribution board for electric consumers is carried out by the command of the upper level system and by the signals built into the controlled rectifier 15 with vector control, voltage sensors and phase currents with the generation of a compensation effect. Compensatory effect consists in changing the modules and phase angles of the current vectors in the input circuit of the controlled rectifier 15 and, accordingly, the shear angles between the current and voltage in each phase. This is accomplished by the formation of controlled rectifier 15 in the input circuit and at the terminals of the three-phase windings of the inductor 3 additional phase voltage vectors. The sum of the phase voltage vectors acting in each phase of the inductor 3 affects the module and the phase angle of the current vector flowing in each phase winding of the inductor. In this case, the vectors of the three-phase voltage system on the buses 1 of the switchboard are aligned modulo with the approximation of the mutual phase shift to 120 electrical degrees. The average value of the voltage at the output of the controlled rectifier 15 remains stable and the inverters 18 and 19 can perform the function specified by the control system 20 according to the driving and braking modes of the module motors.

Thus, the use in the invention of a module of a twin-screw propulsion system of a ring design with two propeller synchronous electric motors driven by permanent magnets, rotating propellers with an anti-directional rotation of the blades and a reversible converter with two separately controlled inverters for powering the propeller motors, including the use of propellers of the impeller type, allows the ship's electric propulsion system to work in both motor and brake modes I have with security:

- increase the propulsion efficiency;

- reduce noise and vibration;

- improving the quality and efficient use of electricity on the switchboard tires due to the controlled rectifier, which provides filtering of the consumed current, stabilization of the output voltage and the possibility of energy recovery for use by ship consumers;

- the simultaneous use of a controlled rectifier of the frequency converter of this installation as a static reactive power compensator and for balancing modulo and phase of the voltage vectors in the supply network with different loading of its phases to further reduce the level of noise and vibration of the ship's electrical equipment.

Claims (1)

The ship’s electric propulsion system, incorporating switchboard buses connected through a circuit breaker and inductor to a reversible frequency converter, the first output of which is connected to the stator winding of the first propeller ring motor with excitation from permanent magnets, in the rotor cavity of which the first fixed propeller is mounted step, characterized in that additionally contains a second rowing electric motor of a ring design with permanent magnet excitation, the stator winding of which is connected to the second output of the frequency converter, a second fixed pitch propeller is installed in the rotor cavity of the second rowing electric motor, both of these motors are aligned and combined into a single module so that their cavities form a through channel, and the blades of the first propeller are made with an opposite direction to the blades of the second gr a screw, the frequency converter contains a controlled rectifier installed at the input, the power output of which is connected to a capacitor storage of the DC link, with a voltage sensor of the DC link and with the power inputs of two inverters that are part of the frequency converter, it also contains two frequency adjusters rotation of electric motors, each of the setters is connected with its first output to the control input of one of the inverters, and with its second output connected to the first output of the other at the same time, the ship's electric propulsion system incorporates a local control system connected to the control input of the controlled rectifier, with the signal output of the voltage sensor on the capacitor storage, with frequency adjusters, as well as with the signal outputs of the first and second current sensors and the first and second sensors the voltage of the phases installed in the output power circuits of the inverters, which are the outputs of the frequency converter, and the connection of the electric motors is made possible unidirectional rotation of their rotors.

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