JPH0446600A - Control method for main machine shaft drive generator - Google Patents

Abstract

PURPOSE:To make it possible to rotate an engine reversely in a short time by operating a main machine shaft drive generating system as a generator untill the air brake of main engine functions at the time of crash astern and then applying brake thereby dropping the rotational speed of engine quickly. CONSTITUTION:Upon provision of a crash astern command, a main engine 5 cuts the fuel to lower rotational speed. A main machine shaft drive generating system sustains operation and the rotary inertia energy of the main engine 5 is converted into electric energy which is then consumed in order to brake the main engine 5. At the same time, operable loads onboard are operated to increase load power so as to increase brake torque. Upon droppage of the rotational speed of the main engine 5, voltage regulator 108 for a shaft generator l performs constant V/F control thus sustaining a constant output. When the current reaches the limit and the output can not be sustained, parallel operation with a Diesel engine generator 7 is performed in order to share the load and to produce a constant torque. When the brake is applied untill air brake of the engine 5 functions, the main machine shaft drive generating system is stopped and separated from a bus 12.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a main engine shaft drive generator for ships, which can quickly reduce the rotational speed of the main engine in the event of a crash astern. The present invention relates to a control method for a shaft-driven power generator.

(Prior Art) A main shaft drive power generator is a system that drives a generator to generate electricity using a ship's main engine, and is used in many ships because of its great effect on energy and maintenance savings. Figure 4 shows a configuration diagram of the main engine shaft drive power generator. In the figure, 1 is a shaft generator, 2 is a converter, 3 is an inverter, 4 is a synchronous phase modifier,
5 is a main engine, 6 is a propeller, 7 is a diesel generator, 8 is a power generation engine, 9 is a load, 10.11 is a circuit breaker, and 12 is a bus bar.

The operation of the conventional main shaft drive power generating device will be explained below with reference to FIG. 4.
This device is composed of 4.

The main engine 5 drives the propeller 6, but also drives the shaft generator 1 at the same time. Since the rotational speed of the main engine 5 changes depending on the navigation state, the frequency of the alternating current power of the shaft generator also changes. Therefore, the converter 2 converts the alternating current into direct current, and the inverter 3 converts the alternating current into constant frequency alternating current power. The synchronous phase modifier 4 supplies reactive power to the inverter and load to keep the voltage constant. The obtained constant frequency and constant voltage power is supplied to the load 9 via the bus 12 through the circuit breaker 10. When entering a port, where the main engine may stop, the diesel generator 7 also operates to supply power in parallel.

According to the main shaft drive power generator operated as described above,
Normally, power can be supplied only by the main shaft drive generator without operating a diesel generator, and it has been used in many ships because it is highly effective in saving energy and maintenance. In order to make a sudden stop in such a ship, a crash astern is performed in which the propeller, ie, the main engine 5, is rotated in the opposite direction to perform braking. The main engine 5 cannot be operated in the opposite direction until it has completely stopped.

When a crash astern is ordered, the main engine's fuel is first cut. The main engine does not stop immediately due to inertia. When the rotational energy of inertia is consumed by frictional resistance and the rotation drops to a predetermined value (for example, about 30%), an air brake that injects air into the cylinder of the main engine is used to suddenly brake the engine. When rotation stops, the main engine is started in reverse rotation and brakes are applied to the hull.

A similar procedure is used to perform a crash astern on ships equipped with a main shaft drive generator. Furthermore, when power is supplied only by the main engine shaft drive generator, first start the diesel generator 7, transfer the load to it, disconnect the main engine shaft drive generator from the bus bar 12 and stop operation, and then start the main engine. It is necessary to perform a stop operation.

(Problem to be Solved by the Invention) When performing a crash astern, it is often an emergency such as collision avoidance, and it is desirable to reduce the rotation of the main engine 5 as soon as possible. In conventional ships, only fuel is cut, the braking force is small, and the inertia of the main engine and shaft is large, so it takes time for the rotation to decrease. In addition, the main engine had to be operated until the load shifted and the main shaft drive generator was stopped, further prolonging the time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of controlling a drive power generator that can shorten the main engine stop time.

[Structure of the invention]

(Means for Solving the Problems) A control method for a main shaft drive power generator according to the present invention applies braking by operating the main shaft drive power generator until the air brake of the main engine operates in the event of a crash astern. This system is characterized by quickly reducing the main engine's rotational speed.

(Function) According to the present invention, the rotational speed of the main engine can be quickly reduced at the time of a crash astern by the above means, and the engine can be operated in reverse in a short time. This makes it possible to improve the safety of navigation of ships.

(Example) FIG. 1 shows an example of a main engine shaft drive power generator to which the method of controlling the main engine shaft drive power generator of the present invention is applied, and FIG. 2 shows signal waveforms of various parts in the example of FIG. 1. In FIG. 1, the same reference numerals as in FIG. 4 indicate the same components.

In Fig. 1, 100 is an output frequency command setter, ]0
1 is an output frequency detector; 102 is a frequency controller that calculates a current command value based on the deviation between the output frequency command and the output frequency detection value; 103 is a current limiter that limits the current command value according to the rating of the inverter 3 converter 2; A current detector, 105, a current controller that calculates the phase of the inverter 3 converter 2 based on the current command value and the current detection value, 106
107 is a phase controller of the converter 2, 107 is a phase controller of the inverter 3, and 108 is a voltage regulator that controls the output voltage of the shaft generator 1.

Next, referring to FIG. 2, the operation at the time of crash astern will be explained. If a crash astern command is received at point A while the main shaft drive generator is supplying power to the load alone, the main engine 5 cuts fuel and lowers the rotation 9
The main engine shaft drive power generator continues to operate as it is, converting the rotational energy of the inertia of the main engine 5 into electrical energy and consuming it, thereby applying braking to the main engine 5. At the same time, those that can be operated with the load inside the ship are operated to increase the load power and increase the braking torque.

When the rotational speed of the main engine 5 decreases, it becomes difficult for the shaft generator 1 to maintain a constant voltage due to saturation of the magnetic circuit, so the voltage regulator 108 performs V/F constant control from point B to maintain a constant magnetic flux. If the output voltage of the shaft generator 1 decreases, the power of the main engine shaft drive generator will decrease, but the converter 2 and inverter 3 of the main engine shaft drive generator can be overloaded for a short time, so the current limit value should be set. increase and keep the output constant.

From the 0 point where the current reaches its limit and the output cannot be maintained, it operates in parallel with the diesel generator 7, which was started in advance at the same time as the crash astern command was generated, to share the load. After the 0 point, the magnetic flux is constant and the current is constant, so the torque is constant, and braking is performed until the air brake of the engine 5 operates up to point D.

After point D, the main engine shaft drive generator is stopped and the train is disconnected from the bus bar 12. After the main engine 5 is stopped, the main engine 5 is started in the reverse rotation direction and the brakes are applied to the hull.

In this example, we have explained the case where there is a crash astern command when only the shaft-driven generator is supplying power to load 9. However, if multiple generators are supplying power in parallel, the load can be turned into shaft-driven generator. It is also effective to concentrate on the aircraft and increase the braking force to the main engine 5. Furthermore, if the main shaft drive power generator is stopped and is being supplied with power by a diesel generator, the main shaft drive power generator may be started and braked at the same time as the crash astern command is issued.

(Other Embodiments) Another embodiment of the present invention is shown in FIG. In the figures, the same reference numerals as in FIGS. 1 and 4 indicate the same components.

201 is a circuit breaker, and 202 is a braking load resistor. In this configuration, the electric power generated by the shaft generator 1 during a crash astern is consumed by a dedicated braking load resistor to apply braking to the main engine 5. Compared to the example shown in FIG. 1, braking can be applied only by operating the circuit breaker, making control easier, but special components are required. In addition, although an example is shown in which the braking load resistor is connected to the shaft generator output terminal, the same effect can be obtained by connecting it to the DC circuit between converter 2 and inverter 3 or to the shaft generator output. .

〔Effect of the invention〕

As described above, according to the method for controlling the main engine shaft drive generator of the present invention, it is possible to apply braking to the main engine in the event of a ship's crash astern, and quickly reduce the rotational speed of the main engine to the rotational speed at which the air brake can be activated. can be lowered to As a result, the engine can be operated in reverse in a short period of time, and the ship can be decelerated, thereby improving the safety of navigation of the ship.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a main shaft drive power generation device to which the main shaft drive power generation device control method of the present invention is applied;
Fig. 2 is a waveform diagram of various parts showing the operation of the control method of the present invention, Fig. 3 is a block diagram showing another embodiment of the invention, and Fig. 4 is a block diagram showing an example of a conventional main shaft drive power generation device. It is. 1.. Shaft generator 2. Converter 3.. Inverter 4.. Rotary harmonizer 5.. Main engine
7-Diesel generator 9...Load 1
0.11,201 Breaker 12... Bus bar
202...Control load resistor (8733) Agent: Patent attorney Yoshiaki Inomata (one person)

Claims (2)

[Claims] (1) A shaft generator driven by the ship's main engine;
In a main shaft drive power generation device comprising a converter that converts the output of a shaft generator into DC, an inverter that converts the DC output of the converter into AC with a constant frequency, and a synchronous phase modifier that supplies reactive power to the inverter and the load, In the event of a crash astern, the main engine shaft drive generator is operated to convert the rotational energy of the main engine into electrical energy, which is then consumed by the load, thereby applying braking to the main engine.
A control method for a main engine shaft drive power generator characterized by quickly reducing the rotation speed and shortening the time until the main engine is reversed. (2) In the method for controlling a main shaft drive power generator according to claim 1, a dedicated braking load resistor is provided, and energy is consumed by the braking load resistor as well as the load. A control method for a main shaft drive power generation device characterized by applying braking to the main engine by causing the main engine to brake.