Variable pitch propeller ship shaft electric excitation synchronous motor and starting method thereof
By directly starting the electrically excited synchronous motor using frequency conversion technology, the problems of large size, heavy weight, and complex transmission chain in the existing technology are solved, achieving the effects of simplified structure, reduced cost, and improved reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-03-10
AI Technical Summary
In existing reversible synchronous motor solutions, permanent magnet synchronous generators have difficulties in magnetic field adjustment and risks of high-temperature demagnetization. The solution of adding an asynchronous starter motor to an electrically excited synchronous generator results in increased size and weight, as well as increased complexity of the transmission chain.
The variable frequency technology is used to directly start the electrically excited synchronous motor. The excitation frequency converter provides power support to the rotor and stator, achieving smooth switching, eliminating the need for asynchronous motor start-up, and simplifying the system structure.
It reduces system size and weight, improves reliability, lowers costs, has a low starting current, reduces mechanical connection parts, reduces failure points, and makes the startup process smooth and controllable.
Smart Images
Figure CN121643386A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of reversible marine shaft generator, in particular to a variable pitch propeller ship shaft generator with electrically excited synchronous motor and a starting method thereof. BACKGROUND
[0002] On modern ships, especially those equipped with electric propulsion or hybrid power systems, shaft generators are an important device. It can not only be driven by the main engine (main engine) to generate electricity (PTO mode), but also can drive the propeller as a motor when needed (PTH mode), improving the flexibility and energy efficiency of the system. For ships equipped with variable pitch propellers (CPP), it is particularly important to achieve PTO / PTH switching.
[0003] However, the synchronous motor itself cannot be directly started and needs auxiliary starting means. There are two main reversible synchronous motor schemes: one is to use a permanent magnet synchronous generator (PMSG), and the other is to use an electrically excited synchronous generator (EESG) with an asynchronous starting motor. The permanent magnet synchronous generator scheme has the problems of difficult magnetic field adjustment, irreversible demagnetization of permanent magnets at high temperatures or faults, high cost, and complex installation process. While the electrically excited synchronous generator with asynchronous starting motor scheme, although the principle is simple, has obvious shortcomings: the larger the generator power, the heavier the rotor, and the larger the asynchronous starting motor volume and weight, which significantly increases the volume, weight and cost of the entire unit. At the same time, the generator and asynchronous starting motor usually need to be installed coaxially, which increases the complexity of the transmission chain, reduces the reliability of the coaxial rotor, and makes installation and maintenance more complicated. SUMMARY
[0004] In view of the deficiencies of the prior art, the present application provides a variable pitch propeller ship shaft generator with electrically excited synchronous motor and a starting method thereof, which aims to abandon the independent asynchronous starting motor, directly start the electrically excited synchronous motor body using frequency conversion technology, and realize smooth switching of modes, thereby simplifying the system structure, improving the reliability, and reducing the volume and weight.
[0005] In order to achieve the above purpose, the present application adopts the following technical scheme: A variable pitch propeller ship shaft generator with electrically excited synchronous motor, comprising a motor starting structure arranged on an electrically excited synchronous generator, the motor starting structure comprising a brush lifting device, an automatic voltage regulator, an excitation frequency converter and a ship power station power supply, which is used to provide power support for the entire motor starting structure. The motor base of the electrically excited synchronous generator is provided with a stator winding and a rotor winding, the stator winding is electrically connected with a stator three-phase terminal, and the rotor winding is divided into two paths and is electrically connected with a DC excitation terminal and a rotating rectifier positive and negative current collector ring, respectively.
[0006] As a preferred technical scheme of the present application, the excitation frequency converter is configured to perform the following operation steps when starting the electrically excited synchronous generator: S1: the DC output thereof provides stable DC excitation current for the rotor winding through the brush lifting device to establish a stable magnetic field inside the motor; S2: the AC output end thereof provides three-phase AC power with controllable frequency and voltage to the stator winding.
[0007] As a preferred technical scheme of the present application, a starting method of a variable-pitch propeller ship shaft-mounted electrically excited synchronous motor is characterized in that it comprises the following steps: S1: the excitation frequency converter issues a command to control the brush lifting device to perform the brush pressing action; S2: starting begins, the excitation frequency converter issues a pulse command to make the three-phase terminals of the stator winding connected, and issues a pulse command to make the DC excitation terminals connected; S3: acceleration operation, the excitation frequency converter controls the electrically excited synchronous generator to gradually accelerate to the rated voltage and rated speed; S4: synchronous switching, the machine-side voltage and phase of the excitation frequency converter are adjusted, the bypass switch is closed when the voltage and phase are consistent with the grid voltage, the excitation frequency converter is removed, the motor stator excitation is switched to be powered by the ship power station, and the motor rotor excitation is switched to be powered by the automatic voltage regulator; S5: starting is completed, and the excitation frequency converter exits the excitation power supply.
[0008] The present application has the following advantages: 1. The present application completely eliminates the bulky and heavy asynchronous starting motor and its transmission mechanism, significantly reduces the installation space and total weight of the entire shaft-mounted power generation device, and is easy to realize automatic control, with smooth and fast mode switching process; 2. The present application reduces mechanical connection components and reduces failure points. The electrically excited synchronous motor itself is more resistant to high temperature than the permanent magnet motor, has no demagnetization risk, and has higher reliability. Although a frequency converter is added, the asynchronous motor and its auxiliary equipment are eliminated, and the overall cost may be more advantageous, especially for high-power systems; 3. The present application uses frequency conversion starting, the starting current is small, the starting torque is smooth and controllable, and the impact on the power grid and mechanical transmission system is much smaller than that of direct starting or asynchronous motor starting. BRIEF DESCRIPTION OF DRAWINGS
[0009] In order to more clearly illustrate the specific embodiments of the present application or the technical schemes in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.
[0010] Figure 1 This is a schematic diagram of the circuit structure of a variable-pitch propeller ship shaft-driven synchronous motor proposed in this invention.
[0011] In the diagram: 1. Electrically excited synchronous generator; 2. Brush lifting device; 3. Automatic voltage regulator; 4. Excitation frequency converter; 5. Ship power station power supply; 6. Stator winding; 7. Rotor winding; 8. Stator three-phase terminals; 9. DC excitation terminals; 10. Rotary rectifier positive and negative slip rings; 11. Bypass switch; 12. Frequency converter rotor excitation switch. Detailed Implementation
[0012] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0013] Reference Figure 1 This embodiment discloses a variable-pitch propeller ship shaft-driven electrically excited synchronous motor, which includes a motor starting structure mounted on an electrically excited synchronous generator 1. The motor starting structure includes a brush lifting device 2, an automatic voltage regulator 3, an excitation frequency converter 4, and a ship power station power supply 5, which provides power support for the entire motor starting structure. Further, the motor frame of the electrically excited synchronous generator 1 is provided with a stator winding 6 and a rotor winding 7. The stator winding 6 is electrically connected to the stator three-phase terminals 8, and the rotor winding 7 is divided into two paths and electrically connected to the DC excitation terminals 9 and the positive and negative slip rings 10 of the rotating rectifier, respectively.
[0014] In this embodiment, when the electrically excited synchronous generator 1 starts, the excitation frequency converter 4 is configured to perform the following steps: S1: its DC output provides a stable DC excitation current to the rotor winding 7 through the brush lifting device 2 to establish a stable magnetic field inside the motor; S2: its AC output provides three-phase AC power with controllable frequency and voltage to the stator winding 6.
[0015] In this embodiment, the starting method of the electrically excited synchronous motor includes the following steps: S1: Excitation frequency converter 4 sends a command to control brush lifting device 2 to perform brush pressing action; S2: Start-up begins, excitation frequency converter 4 sends a pulse command to connect the three-phase terminals 8 of the stator winding, and excitation frequency converter 4 sends a pulse command to connect the DC excitation terminal 9; S3: Acceleration operation, excitation frequency converter 4 controls the electrically excited synchronous generator 1 to gradually accelerate to the rated voltage and rated speed; S4: Synchronization switching, the machine-side voltage and phase of excitation frequency converter 4 are adjusted, and when the voltage and phase are consistent with the grid voltage, the bypass switch 11 is closed to disconnect excitation frequency converter 4, the stator excitation of the motor is switched to be powered by the ship power station power supply 5, and the rotor excitation of the motor is switched to be powered by the automatic voltage regulator 3; S5: Start-up complete, excitation frequency converter 4 disconnects from the excitation power supply.
[0016] The starting principle of the electrically excited synchronous generator 1 of this invention is as follows: First, when the electrically excited synchronous generator 1 needs to be started by electric operation, the excitation frequency converter 4 provides DC excitation power to the main rotor winding 7 through the brush lifting device 2, so that the main rotor establishes a stable magnetic field; second, the excitation frequency converter 4 provides three-phase AC excitation power to the stator winding 6 of the generator, and controls the frequency of the AC excitation power through the excitation frequency converter 4 to increase the rotor speed from zero speed to rated speed; the excitation power of the stator winding 6 is switched to the ship's power grid through the bypass switch 11, and the frequency converter rotor excitation switch 12 is opened, switching to the automatic voltage regulator 3 to provide excitation; finally, the start-up of the electrically excited synchronous generator 1 is completed.
[0017] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A variable pitch propeller ship shaft generator comprising a motor start-up structure provided on an electrically excited synchronous generator (1), characterized in that, The motor starting structure comprises a brush lifting device (2), an automatic voltage regulator (3), an excitation frequency converter (4) and a ship power station power supply (5), which are used for providing power support for the whole motor starting structure. The motor base of the electrically excited synchronous generator (1) is provided with a stator winding (6) and a rotor winding (7), the stator winding (6) is electrically connected with a stator three-phase terminal (8), and the rotor winding (7) is electrically connected with a direct-current excitation terminal (9) and a rotating rectifier positive and negative current collecting ring (10) in two paths.
2. A variable pitch propeller ship shaft generator with electric excitation according to claim 1, characterized in that, The excitation frequency converter (4) is configured to perform the following operation steps when the electrically excited synchronous generator (1) starts: S1: The direct-current output thereof provides stable direct-current excitation current for the rotor winding (7) through the brush lifting device (2) to establish a stable magnetic field in the motor; S2: The alternating-current output end thereof provides three-phase alternating current with controllable frequency and voltage for the stator winding (6).
3. A method of starting a variable-pitch propeller ship shaft synchronous motor with electric excitation according to claim 1, characterized in that, The method comprises the following steps: S1: The excitation frequency converter (4) sends a command to control the brush lifting device (2) to perform a brush pressing action; S2: Start, the excitation frequency converter (4) sends a pulse command to make the stator winding three-phase terminal (8) connected, and the excitation frequency converter (4) sends a pulse command to make the direct-current excitation terminal (9) connected; S3: Accelerate, the excitation frequency converter (4) controls the electrically excited synchronous generator (1) to gradually accelerate to rated voltage and rated speed; S4: Synchronous switching, adjust the machine side voltage and phase of the excitation frequency converter (4), calculate and close the bypass switch (11) when the grid voltage size and phase are consistent, cut off the excitation frequency converter (4), the motor stator excitation is converted to be powered by the ship power station power supply (5), and the motor rotor excitation is converted to be powered by the automatic voltage regulator (3); S5: Start complete, the excitation frequency converter (4) exits the excitation power supply.