JPH0739299U - Voltage controller for main shaft drive generator - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention can maintain a high power factor of the inverter from no load to full load, and can perform stable and fast response voltage control of the main shaft drive generator. It is to provide a control device. According to the present invention, in a voltage control device of a main shaft drive power generator having a shaft generator driven by a main engine of a ship, a current detector for detecting an output current of the shaft generator and its current detection. A function generator that generates a function based on the value and a calculator for correcting the terminal voltage command value of the voltage regulator by the output signal of the function generator are provided, and the output current of the shaft generator is used to Since it is configured to correct the terminal voltage of the shaft generator, the power factor of the inverter can be maintained at a high power factor from no load to full load, and stable and fast response control is possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a main shaft drive power generator for a ship, and more particularly to a voltage control device for a main shaft drive power generator capable of performing stable control even when the shaft generator has a low speed and the commutation reactance of the converter is large.

[0002]

[Prior art]

 The main shaft drive generator is a system that drives a generator by the main engine of a ship to generate electricity, and is highly effective in saving energy and maintenance, and is used in many ships.

Such a conventional main shaft drive generator will be described with reference to the configuration diagram shown in FIG. In the figure, 1 is a shaft generator, 2 is a converter, 3 is an inverter, 4 is a synchronous phase modulator, 5 is a main engine, 6 is a propeller, 7 is a load, 8 is a circuit breaker, 9 is a busbar, 10 is an output frequency. A command setter, 11 is an output frequency detector, 12 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, and 13 is a first current that detects the output current of the inverter. A detector, 14 is a current controller that calculates the phases of the inverter 3 and the converter 2 so that the current command value and the detected current value match, 15 is a phase controller of the converter 2, 16 is a phase controller of the inverter 3, 17 Is a first voltage regulator that controls the terminal voltage of the shaft generator 1, 18 is a second voltage regulator that controls the terminal voltage of the synchronous phase shifter 4, 19 is a rotation speed detector, and 20 is a voltage command calculator Is.

Next, the operation of the above-described conventional main shaft drive generator will be described. The main engine 5 drives the propeller 6, but at the same time drives the axial generator 1. The rotation speed of the main engine 5 changes depending on the sailing condition. The magnitude of the terminal voltage of the shaft generator 1 can be controlled to a desired value by the first voltage regulator 17, but the frequency changes depending on the engine speed. Therefore, the converter 2 once converts the alternating current into the direct current, and the inverter 3 converts the alternating current into the constant frequency alternating current power. The synchronous phase shifter 4 supplies reactive power to the inverter 3 and the load 7 to keep the voltage of the bus 9 constant. The obtained constant frequency constant voltage power is supplied to the load 7 through the breaker 8 and the busbar 9. Since the electric power supplied from the shaft generator 1 to the load 7 is proportional to the current, the electric power corresponding to the load 7 is supplied, and the frequency controller 12 and the current controller 14 control the current so that the output frequency of the inverter 3 becomes stable. Are in control.

The main engine 5 of the ship is a large-capacity machine and has a low rotation speed. Therefore, the shaft generator 1 is also a low speed machine having an output frequency of 5 to 20 Hz. In general, low-speed machines have large dimensions and shapes, and even small differences in output capacity cause considerable changes in dimensions. Therefore, if the power factor of the shaft generator 1 is operated as close to 1 as possible, the external dimensions can be reduced. Therefore, during the power generation operation, the converter 2 is operated at the control angle α = 0 °, and the phase control of the inverter 3 adjusts the current. If this is done, the external dimensions of the synchronous phase shifter 4 will be large, but since it is a high-speed machine, it can be handled with a smaller increase in size than a low-speed machine.

[0006]

[Problems to be solved by the device]

 According to the main shaft drive power generator operated as described above, a power source of constant frequency and constant voltage can be obtained from the power of the main engine, which is effective in energy saving and maintenance. However, in the conventional system, when the load is small, if the terminal voltage of the shaft generator 1 is controlled to be constant, there is a problem that the current control in the inverter 3 may become unstable.

This is because during normal power generation operation, the converter 2 operates so that the maximum DC output voltage is obtained at a constant control angle α = 0 °, and the current supplied to the load is controlled by the β phase control of the inverter 3. Have control. Looking at the inverter 3 side, the DC voltage V _dc and the terminal voltage V _{s / c} of the synchronous phase modulator 4 are constant, and the DC voltage V _dc , the terminal voltage V _{s / c of the} synchronous phase _modulator , and the control advance angle β. , The commutation overlap angle u is expressed by the following equation.

[Equation 1]

When the load is large and the commutation overlapping angle u is large, the control advance angle β is also large and the variable range of β with respect to the β limit value is large, but the load is small and the commutation overlapping angle u is small. When the value is small, the control advance angle β also becomes small, and even a slight change in the current results in β limit, which makes the current control unstable. The current controller 14 tries to control the current by the α phase control of the converter 2 when the control of the inverter 3 becomes β limit and the current cannot be controlled. For example, when the load becomes small and the direct current is decreased, the phase control of the inverter 3 becomes β limit, and the converter 2 side also enters the α phase control mode. Looking at the current control response of the system, since the shaft generator 1 is a low-speed machine and the output frequency is low, the response of the phase control of the converter 2 is slower than the response of the phase control of the inverter 3, and The response is also slow.

When the normal converter 2 is operated at a constant control angle α = 0 °, a fast control response by the inverter 3 can be expected, but when the converter 2 side is in a mode for performing α phase control, the system control response is converter. The control response on the 2nd side becomes slow. Moreover, there is a problem that not only the response is slow but also the control becomes unstable.

The present invention has been made in view of the above circumstances, and an object thereof is to maintain the power factor of the inverter at a high power factor from no load to full load, and to perform stable and fast response control. It is an object of the present invention to provide a voltage control device for a main spindle drive power generator.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a shaft generator driven by a main engine of a ship, a voltage regulator for controlling a terminal voltage of the shaft generator, and an output of the shaft generator to direct current. In the voltage control device of the main shaft drive generator, the converter, the inverter for converting the DC output of the converter into a constant frequency alternating current, and the synchronous phase shifter for supplying reactive power to the inverter, A current detector that detects the output current of the shaft generator, a function generator that generates a function based on the detected current value, and the terminal voltage command value of the voltage regulator is corrected by the output signal of the function generator. And an arithmetic unit for adjusting the terminal voltage of the shaft generator according to the output current of the shaft generator.

[0012]

[Action]

 According to the present invention, a voltage that controls the terminal voltage of the shaft generator by detecting the output current of the shaft generator and correcting the terminal voltage command value with a function according to the generated load based on that value. Because of the regulator configuration, the power factor of the inverter can be maintained at a high power factor from no load to full load, and stable and fast response control is possible.

[0013]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. The present embodiment is different from the conventional example shown in FIG. 3 only in the configuration in which the second current detector 21, the filter circuit 22, the function generator 23, and the calculator 24 are provided, and the other configurations are the same. Therefore, the same parts are designated by the same reference numerals and the description thereof will be omitted.

Next, the operation of the voltage controller of the main shaft drive generator of this embodiment will be described. If the converter output voltage is constant from no load to full load, the inverter side power factor can be designed to always operate at a high power factor, so the capacity of the synchronous phase shifter can be reduced. In addition, the withstand voltage of the converter and inverter elements need not be designed according to the rated load, and efficient design is possible. And stable and fast response control is also possible. Therefore, in this embodiment, a second current detector 21 that detects the output current of the shaft generator 1, a function generator 23 that generates a function based on the current detection value processed by the filter circuit 22, and a terminal voltage. An arithmetic unit 24 for correcting the command value by the output signal of the function generator 23 is provided, and the terminal voltage of the shaft generator is corrected by the output current of the shaft generator 1.

With such a configuration, the terminal voltage of the shaft generator 1 can be controlled to an appropriate value during the power generation operation of the main shaft drive generator, regardless of the size of the load. Therefore, in the conventional method, even when the load becomes small, the phase control of the inverter 3 becomes β limit, and the converter 2 side also enters the α phase control mode and the current control response of the system becomes slow, the shaft generator 1 Since the magnitude of the load is detected from the output current of 1 and the terminal voltage command value of the shaft generator 1 is corrected by the function generator 23, the converter 2 operates with the control angle α = 0 ° kept constant, Since the current supplied to the load can be controlled by the β phase control of the inverter 3, fast control by the inverter 3 is possible. In addition, the instability phenomenon caused by the delay of the current control response is eliminated, and stable and fast response control is possible from no load to full load.

FIG. 2 shows an example of a function pattern by the function generator of the present invention. The horizontal axis represents the output current of the shaft generator 1, which is approximately proportional to the size of the load. The vertical axis is a signal for correcting the terminal voltage command value of the shaft generator 1, and has a function pattern that lowers the terminal voltage command value when the load is small. As a result, the converter 2 can be operated with the control angle α = 0 ° kept constant, and the phase control of the inverter 3 can be operated with a sufficient margin with respect to the β limit, and the inverter 3 can perform fast control. . Moreover, the above-mentioned function pattern is an example, and an arbitrary pattern can be set according to the purpose.

In this embodiment, the independent filter circuit 22, the function generator 23, the calculator 24, the voltage command calculator 20, the control amplifier 17 and the like are provided, but the present invention is not limited to this. Alternatively, the same controller as the frequency controller 12 and the current controller 14 can be used to implement the software. In addition, although the configuration in which the converter and the inverter are directly coupled is shown in the present embodiment, a configuration in which a DC reactor is interposed may be used.

[0018]

[Effect of device]

 As described above, according to the voltage controller for the main shaft drive generator of the present invention, the power factor of the inverter can be maintained at a high power factor from no load to full load, and the capacity of the synchronous phase shifter is reduced. It is also possible to achieve stable and fast response control regardless of the load.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a voltage controller for a main shaft drive generator of the present invention.

FIG. 2 is a diagram showing an example of a function pattern by the function generator of FIG.

FIG. 3 is a block diagram of a conventional voltage control device for a main shaft drive generator.

[Explanation of symbols]

1 ... Shaft generator, 2 ... Converter, 3 ... Inverter, 4 ...
Synchronous phase shifter, 5 ... Main engine, 6 ... Propeller, 7 ... Load, 8 ... Circuit breaker, 9 ... Bus bar, 10 ... Output frequency command setter, 11 ... Output frequency detector, 12 ... Frequency controller, 1
3, 21 ... Current detector, 14 ... Current controller, 15, 16
... phase controller, 17, 18 ... voltage regulator, 19 ... rotation speed detector, 20 ... voltage command calculator, 22 ... filter circuit,
23 ... Function generator, 24 ... Operation unit.

Claims (1)

[Scope of utility model registration request] 1. A shaft generator driven by a main engine of a ship, a voltage regulator for controlling a terminal voltage of the shaft generator, a converter for converting an output of the shaft generator into a direct current, and a converter for the converter. In a voltage control device of a main shaft drive generator including an inverter that converts a DC output into a constant frequency AC, and a synchronous phase shifter that supplies reactive power to the inverter and a load, the output current of the shaft generator is detected. A current detector, a function generator for generating a function based on the detected current value, and an arithmetic unit for correcting the terminal voltage command value of the voltage regulator by the output signal of the function generator. A voltage control device for a main shaft drive generator, characterized in that a terminal voltage of the shaft generator is corrected by an output current of the shaft generator.