JPS6118398A - Generator control system for motor - Google Patents

Abstract

PURPOSE:To improve the thermal efficiency of an internal combustion engine by decelerating the rotating speed of the engine when a load power increases to set the power from an AC generator to a load power or larger. CONSTITUTION:An AC generator 2 is driven by an internal combustion engine 1, and AC power is supplied through a line 6 and switches 7, 8 to loads 9, 10. A processor 14 applies a control signal to a speed regulator 5 in response to the frequency of the power of a line 6 detected by a frequency detector 15. The processor 14 also applies a control signal to the regulator 5 when the power of the line 6 detected by a power meter 13 increases larger than the maximum allowable power of the motor 2 to decelerate the speed of the engine 1. Thus, the generator does not stop due to the overload to enhance the reliability.

Description

Detailed Description of the Invention Technical Field The present invention relates to an internal combustion engine that rotates an alternator to generate alternating current power, and uses this alternating power to energize a motor, which is a centrifugal fluid machine, such as a centrifugal or This invention relates to a power generation control method for a motor that rotates a fan or pump such as an axial flow type.

BACKGROUND TECHNOLOGY In the prior art, the capacity of the alternator and the internal combustion engine that drives it are determined in order to ensure that the large current generated when starting the motor, which is the load of the alternator, is supplied. The capacity is selected to be larger than the capacity that corresponds to the constant load. Therefore, during steady state operation, the internal combustion engine operates at a capacity lower than the maximum allowable capacity of the internal combustion engine. As a result, the installed capacity becomes large and the thermal efficiency is poor.

Purpose An object of the present invention is to provide an improved power generation control method for a motor that can keep equipment capacity low and improve thermal efficiency.

Structure of the Invention The present invention rotates an alternator by an internal combustion engine,
The electric power from the alternator energizes the motor, which rotates the centrifugal fluid machine, and when the load power of the alternator exceeds a predetermined value corresponding to the frequency of the alternator, the internal combustion engine starts operating. This is a power generation control method for a motor characterized by reducing the rotational speed so that the power capacity of the alternator becomes twice as much as the load power.

Function According to the present invention, when the load power of the alternator exceeds a predetermined value corresponding to the frequency of the alternator, for example, the maximum allowable output, the rotational speed of the internal combustion engine is reduced. This reduction in the rotational speed of the internal combustion engine causes the frequency of the alternator to decrease. The motor drives the centrifugal fluid machine at 11 W, and the rotational speed of this motor is approximately proportional to the frequency of the alternator. On the other hand, the power required to rotate a centrifugal fluid machine is approximately proportional to the rotational speed of the centrifugal fluid machine. Therefore, by reducing the speed of the internal combustion engine (civil cycle 1) and lowering the frequency of the alternator, the power required to drive the rotation of the centrifugal fluid machine is significantly reduced, and therefore the motor The load power applied to the alternator is reduced so that the power from the alternator exceeds the load power.This makes it possible to lower the maximum permissible output of the alternator and the maximum capacity of the internal combustion engine that rotationally drives the alternator. Become.

The embodiment drawing is a system diagram of an embodiment of the present invention. internal combustion engine 1
drives the alternator 2 to rotate. The alternating current generator 2 is, for example, a synchronous generator. In this internal combustion engine 1, the opening degree of the intake pipe 3 and the throttle 4 are controlled by the speed #product 5. AC power from the alternator 2 is transmitted from the line 6 to the motor 9, which is the load, via the switch 7.8.
10. The motors 9 and 10 may be induction motors or the like, and have rotational speed characteristics that are approximately proportional to the frequency of the electric power from the line 6. A motor 9110 drives a centrifugal fluid machine 11.12 on four axes. The centrifugal fluid machines 11, 12 are centrifugal or axial fans, pumps, or the like, and have a configuration that requires rotational power approximately proportional to the cube of the rotational speed.

Load power flowing through line 6 is detected by wattmeter 13 and provided to processing circuit 14 . The frequency of the power on line 6 is detected by frequency detector 15 and provided to processing circuit 14 . The processing circuit 14 is realized by, for example, a micro combinator, and its @calculated output is given to the speed regulator 5, thereby controlling the throttle valve 4.
The opening degree is controlled.

Assume a steady state in which the switch 7 is conductive, the switch 8 is disconnected, only the motor 9 is energized, and the centrifugal fluid machine 11 is rotationally driven. When the switch 8 is turned on to start the motor 1o in this steady state, a large load current flows through the inlet 6. The processing circuit 14 receives from the wattmeter 13 the number 1 representing the load power on the line 6 detected by the power, 71''] 3, and determines the opening degree of the throttle valve 4 by the speed regulator 5, thereby controlling the internal combustion. (The same IQ of civilian 1: The number is lowered and controlled so that the frequency detected by the frequency detector 15 of the alternator 2 becomes a predetermined value. As a result, the motor 9
, 10 decreases, and the centrifugal fluid machine i'+, 12
rotation speed decreases. Since the rotational power generated by the morphs 9 and 1o of the centrifugal fluid machine 11.12 is approximately proportional to the rotational speed, the reduction in rotational power due to a decrease in the rotational speed is extremely large. As a result, the load power of the motors 9 and 10 is reduced by j, and this load power falls within the maximum allowable power Jυ of the alternator 2. In this way, the processing circuit 14 has an internal combustion fi 13 (of 11 The rotational speed and therefore the frequency of the alternating current generator (2) is calculated. In this way the load power is kept within the maximum permissible power of the alternating current generator (2). There is no need to unnecessarily increase the installed capacity of the facility, and it becomes possible to improve the thermal efficiency of the facility.

In the two-sided embodiment, the frequency of the power on the line 6 is detected by the frequency detector 15, and the frequency is set to a predetermined value so that the load power is within the maximum allowable power of the AC M1 power generating station 2. However, as another embodiment of the present invention, the rotational speed of the internal combustion engine 1 may be detected and provided to the processing circuit 14 instead of detecting the frequency.

According to the present invention, when the load power becomes large, the rotational speed of the internal combustion engine is reduced so that the power from the alternator exceeds the load power, so that the alternator In addition, the installed capacity of the internal combustion engine is small, the thermal efficiency of the internal combustion engine is improved, and the alternator can continue to operate, for example, close to the limit of the maximum allowable power, so that the efficiency is J: It becomes.

In the conventional system, when multiple generators driven by Ennon are operated in parallel, if one of them fails, the remaining generators are overloaded, resulting in an overload of power generation, resulting in a chain reaction. The generator will be stopped by the overload detection device. In the present invention, even if one generator fails, the frequency is lowered and operation continues with the load supported by the remaining healthy generators, resulting in high reliability.

In addition, regardless of whether generators A or II are operated in single mode or in parallel, if a load greater than the full generation capacity is connected, in conventional systems the generator will be stopped by the generator's overload detector, but with the present invention, , the frequency is lowered to reduce the load on the generator within the time that the generator can withstand the overload, so the generator is highly reliable without being shut down due to overload.

[Brief explanation of the drawing]

The drawing shows system No. 1 of one embodiment of the present invention.

Claims (1)

[Claims] An alternator is driven to rotate by an internal combustion engine, a motor is energized by electric power from the alternator, the motor rotationally drives a centrifugal fluid machine, and the load power of the alternator is power generation for a motor, characterized in that when the frequency of the alternator exceeds a predetermined value corresponding to the frequency of the alternator, the rotational speed of the internal combustion engine is reduced so that the power capacity of the alternator exceeds the load power. control method.