JP4455836B2 - Power generation device and method for controlling power generation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power generation technology that can continue power generation while protecting the power generation device even when the driving force contributing to power generation of the generator increases and the power generation device becomes overloaded. .
[0002]
[Prior art]
In an electric motor, when an overload state in which a current larger than the rated current of the electric motor continues, the temperature inside the electric motor rises abnormally and the electric motor burns out. The same can be said for the generator, and it is necessary to protect it so that it does not burn out even if the generator is overloaded.
[0003]
In the case of an electric motor, a thermal relay is provided in the electric motor and the current is monitored. If an abnormal current occurs, the input power of the electric motor is cut off, or if an inverter is used, the output current to the electric motor is monitored. When it is determined that the output current is abnormal, it is common to forcibly stop the motor so that the inverter cuts off the output to the motor.
[0004]
In the case of a generator, there is a similar method. For example, as in Patent Document 1, the load current of a grid-linked inverter is monitored, and when the load current value exceeds a certain set value, the operation of the inverter is stopped. There is a method for protecting the power generator.
[0005]
When such a protection method is taken, if the fluctuation range of the driving force contributing to the power generation of the generator is large and the driving force increases and falls into an overload state, the power generation stops and the power generation The machine must be stopped for a while to cool down.
[0006]
In another overload protection method, Patent Document 2 describes the maximum power generation output control for protecting the generator capacity over, but does not describe current suppression, and details of the means are described. Is not shown.
[0007]
[Patent Document 1]
JP 2002-186172 A [Patent Document 2]
Japanese Patent Laid-Open No. 2002-257026
[Problems to be solved by the invention]
The object of the present invention is to continue power generation without stopping the device even when the driving force contributing to power generation of the generator increases and the power generator falls into an overload state, and to protect the device. A power generation apparatus and a method for controlling the power generation apparatus are provided.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a generator such as a brushless synchronous generator, a power generation control device that determines a rotational speed command and outputs the rotational speed to the generator, and a driving force that contributes to power generation. The power generation control device constitutes a power generation device having a current detector at the output to the generator.
[0010]
That is, the present invention is a power generator including a generator that generates electric power with a driving force that contributes to power generation, and a power generation control device that controls the amount of power generation by controlling the number of revolutions of the generator. , the power generation control device includes a current detecting means for detecting a current flowing to the generator, wherein the current flowing through the generator is set in advance an upper limit current value, the current value detected by the previous SL current detecting means And a current suppressing means for increasing the rotational speed of the generator so that the current value is equal to or less than the upper limit current value when the upper limit current value is exceeded .
Further, in the present invention, when controlling the amount of power generation by controlling the number of revolutions of the generator that generates power by the driving force that contributes to power generation, the value of the current flowing through the generator exceeds the preset upper limit current value. In such a case, there is provided a control method for a power generation device in which the rotational speed of the generator is increased so that the current value is equal to or less than the upper limit current value.
[0011]
Moreover, in this invention , the said upper limit electric current value is determined by the rotation speed of the said generator .
[0012]
In the present invention , when the driving force is equal to or greater than a specified value, and when the value of the current flowing through the generator exceeds the upper limit current value, the current value is the upper limit current value. The number of revolutions of the generator is increased so that
[0013]
In the present invention, the driving force is generated by a windmill or a water turbine .
[0014]
Further, in the above power generation control device, detection means for detecting a contributing driving force to the power generation, when the detected current value exceeds the upper limit current value, increasing the value of the rotational speed command of the generator Te to suppress current flowing to the generator, a power generator and a control unit that performs the cancellation determination the current suppression control by variation of the detected value of the driving force detecting means.
[0015]
The power generation control device in the present invention can generate power by increasing the regenerative state by decreasing the number of revolutions of the generator, and can control the power generated from the power generator by controlling the strength of the regenerative power.
[0016]
The power generation control device according to the present invention compares the current value detected by the current detector with the upper limit current value of the power generation device, and if the detected current value exceeds the upper limit current value of the power generation device, the rotation of the generator The regenerative power can be weakened by increasing the number, and the current value flowing through the generator can be suppressed below the upper limit current value.
[0017]
Since the power generation control device according to the present invention includes a control unit that performs determination for canceling the current suppression control, the determination for cancellation can be performed based on the variation in the detection value from the driving force detector.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
The Example of the electric power generating apparatus of this invention is described using FIGS. 1-2. FIG. 1 is a configuration diagram of a power generator according to an embodiment. FIG. 2 is an explanatory diagram of a flowchart of current suppression control performed by the power generation control device in the embodiment.
[0019]
Examples will be described. In FIG. 1, the block diagram of the electric power generating apparatus of a present Example is shown. Reference numeral 2 denotes a generator such as a brushless synchronous generator, and reference numeral 3 denotes a converter for converting the energy from the energy source 4 into rotational motion, such as a windmill or a watermill. Reference numeral 1 denotes a power generation control device that controls the amount of regeneration by controlling the number of revolutions of the generator 2 to adjust the amount of power generation.
[0020]
The power converter 9 in the power generation control device 1 converts the alternating current output from the generator 2 into direct current and supplies it to the smoothing capacitor 11 to obtain direct current output, and converts the direct current voltage of the smoothing capacitor into alternating current. This is a module composed of a semiconductor switch that generates a rotating magnetic field that is applied to the electric element of the generator 2 to drive the generator 2. The generated power is converted into a DC output by the power converter 9, smoothed by the smoothing capacitor 11, and output to the system linkage device or the load 13.
[0021]
As for the rotational speed of the generator 2, the frequency at which the efficiency of the generator 2 is maximized is normally transmitted to the frequency command generator 8 by the command frequency calculator 10, and the frequency command generator 8 operates the switch of the power converter 9. Then, the generator 2 is rotated at the specified rotation speed.
[0022]
In such a power generation system, when the energy source 4 fluctuates and the capacity of the generator 2 is exceeded and power generation occurs, the operation of the generator 2 is stopped by the operation of a thermal relay or electronic thermal, Time to cool the raised temperature of the generator 2 is required. Therefore, in this embodiment, a current detector 12 is provided in a portion that is output from the power converter 9 in the power generation control device 1 to the generator 2 to monitor the current value flowing through the generator 2, and the current value is the upper limit. If the current value is exceeded, the degree of regeneration is weakened and the operation is performed so as not to exceed the upper limit current value.
[0023]
The generator 2 is cooled by a fan attached to the rotating shaft of the generator 2, and the degree of cooling varies depending on the number of rotations of the generator 2, so the upper limit current value of the generator 2 varies depending on the number of rotations. Therefore, the power generation control device 1 includes an upper limit current function unit 5 that feeds back the current rotational speed of the generator 2 and calculates an upper limit current value from the rotational speed.
[0024]
Hereinafter, the current suppression control will be described with reference to FIG. Control is started (step S100). Next, the current command rotational speed N * is read (step S101), and the upper limit current function unit 5 calculates the upper limit current Ilimit (step S102). The calculated upper limit current value Ilimit is differentiated from the current value I detected by the current detector 12 by the differentiator 6 (step S103), and the rotational speed increment value ΔN is calculated from the difference value by PID compensation (step S104). ), The rotational speed command generator 8 makes a current suppression execution determination based on ΔN, the command rotational speed N from the command rotational speed calculator 10 and the current command rotational speed N * (step S105). The number is set to a value (N ′) obtained by adding the rotation speed increment value ΔN to the current command rotation speed N * (step S106). The generator whose rotational speed has increased has a reduced degree of regeneration and the amount of power generation is reduced, and the value of the current flowing through the generator is also reduced (step S107). After a certain time, control is started again from the beginning (step S100), and if the current value exceeds the upper limit current value, the rotational speed is increased. By repeating the above operation, the rotational speed is controlled so that the current value I does not exceed the upper limit current value Ilimit.
[0025]
If it is determined in the current suppression execution determination (step S105) that there is no execution, the command rotational speed N calculated by the command rotational speed calculator 10 is commanded (step S108). Execution of current suppression is as follows: (1) The current value I exceeds the current upper limit value Ilimit, (2) The command speed N calculated by the command speed calculator is equal to or less than the current command speed N *. (3) The driving force (energy source 4) contributing to power generation during the current suppression control is performed on condition that it is equal to or greater than a specified value (90% of the driving force when current suppression is started). The condition (1) is a basic condition for current suppression execution. The condition of (2) is that when the command rotational speed N is higher than the current command rotational speed N *, it is not necessary to perform the current suppression control because the operation is being performed in the direction in which the current is suppressed. is there. The condition of (3) is that when the current suppression control is activated and the rotational speed is increased and the current value I is controlled to be lower than the upper limit current value Ilimit, the normal rotational speed is immediately returned to the normal rotational speed N. In order to prevent hunting of the suppression operation, it is a condition for returning to the normal operation unless the driving force that contributes to power generation is reduced to such an extent that it does not become an overload state even if it returns to the normal operation. The driving force is detected by a driving force detector 14 attached to the energy source 4 (for example, a water meter or a pressure sensor in the case of a water turbine power generation system). When the driving force detector 14 is not used, the current value I in the current suppression control is set to a specified value (90% of the upper limit current value Ilimit) or more in the condition (3). Provide hysteresis for the start and end currents.
[0026]
The above embodiment is an example in which the upper limit current function unit 5 is used to determine the upper limit current value Ilimit. However, when the upper limit current value does not vary depending on the rotation speed, the upper limit current function unit 5 is replaced with Is set and stored, and a fixed value set in the setting device is set as the upper limit current value.
[0027]
As described above, according to the present invention, when the driving force that causes power generation using the generator fluctuates, an overload of the power generating device when the driving force increases is reduced. It is possible to protect without stopping.
[0028]
【The invention's effect】
According to the present invention, with the generator contribute driving force to the power generation of the generator is increased device continues power generation without stopping the device even when overburdened, and can protect the device Become.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a power generator according to an embodiment.
FIG. 2 is an explanatory diagram of a flowchart of current suppression control performed by the power generation control device according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Power generation control apparatus 2 Generator 3 Converter to rotational motion 4 Energy source 5 Upper limit current function unit 6 Adder 7 PID
8 Rotational Speed Command Generator 9 Power Converter 10 Command Rotational Speed Calculator 11 Smoothing Capacitor 12 Current Detector 13 System Linkage Device, Load 14 Driving Force Detector

Claims (8)

A generator that generates electric power by a driving force that contributes to power generation;
A power generation control device that controls the amount of power generation by controlling the number of revolutions of the generator,
The power generation control device includes a current detecting means for detecting a current flowing to the generator, wherein the current flowing through the generator is set in advance an upper limit current value, the current value detected by the previous SL current detecting means A power generation device comprising: current suppression means for increasing the number of revolutions of the generator so that the current value becomes equal to or less than the upper limit current value when the upper limit current value is exceeded . The power generator according to claim 1, wherein
The upper limit current value is determined by the number of revolutions of the generator. The power generator according to claim 1 or 2,
A driving force detecting means for detecting the driving force, wherein the current suppression means is a current value detected by the current detecting means when the driving force detected by the driving force detecting means is equal to or greater than a specified value; When the value exceeds the upper limit current value, the generator speed is increased so that the current value becomes equal to or lower than the upper limit current value . 4. The power generation apparatus according to claim 1, wherein the driving force is generated by a windmill or a water turbine . In a control method of a power generator that controls the amount of power generation by controlling the number of revolutions of a generator that generates electric power by a driving force that contributes to power generation,
When the current value flowing through the generator exceeds a preset upper limit current value, the number of revolutions of the generator is increased so that the current value is equal to or less than the upper limit current value . Control method. In the control method of the electric power generating apparatus of Claim 5,
The method of controlling a power generator, wherein the upper limit current value is determined by a rotational speed of the generator. In the control method of the electric power generating apparatus of Claim 5 or 6,
When the driving force is equal to or greater than a specified value, and the value of the current flowing through the generator exceeds the upper limit current value, the power generation is performed so that the current value is equal to or less than the upper limit current value. A method for controlling a power generator, characterized in that the number of revolutions of the machine is increased. In the control method of the electric power generating apparatus in any one of Claim 5 thru | or 7,
The method for controlling a power generator, wherein the driving force is generated by a windmill or a water turbine.

Images