JPS6016197A - Automatic frequency regulator of generator - Google Patents

Abstract

PURPOSE:To enable to obtain a stable set value by applying the set value for the frequency of a generator by the output of a counter. CONSTITUTION:An arithmetic circuit 16 calculates the set value necessary at that time from the given data, and an output circuit 17 outputs a control signal 17b indicating the direction of the rising or falling frequency and a pulse 17a of a pulse train signal of the number corresponding to the rising or failling amount on the basis of the calculated result. A counter 19 up or down counts the pulse 17a from the output circuit 17, and inputs the counted result through a digital- to-analog converter 20 as a frequency set value to an operational amplifier 10. The amplifier 10 controls the frequency of the generator 1 so that the deviation between the value of the frequency signal and the set value of the generator 1 becomes minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic frequency adjustment device that performs control to automatically maintain a generator frequency at a desired set value.

Conventionally, there has been a device of this type as shown in FIG.

In the figure, 1 is a generator, 2 is an electric motor, 2atj is a variable speed device that controls the speed of the electric motor 2, and a three-digit generator. 4 is a breaker f' connected in series to the output end of the generator 1; 5 is a step-down transformer; 6 is a frequency detection circuit; 7.7
a, 8.8a are resistors, 9 is a capacitor, and 10 is an operational amplifier, which together with the resistors 7, 8.8a and the capacitor 9 constitute a deviation amplification circuit. 11 is a phase control circuit into which the output signal of the operational amplifier 10 is input; 12 is an ignition circuit which uses the output signal of the phase control circuit 11 manually; 13 is an ignition circuit 1
The rotational speed of the variable speed device 2a, that is, the motor 1, is controlled by the thyristor whose output is selectively ignited. 14 is an automatic frequency adjustment circuit consisting of transformer 5 to thyristor 13; 15
indicates a frequency setter, and PI3 indicates a DC voltage.

The operation will be briefly explained. The set value input from the frequency setter 15 is input to the operational amplifier via the resistor 7a.

Further, the output of the generator 1 is inputted to a frequency detection circuit 6 via a transformer 5, and its frequency is detected. A signal indicating this frequency is input to the operational amplifier 10 through the resistor T at a potential opposite to that of the set value input. Therefore, the output of the operational amplifier 10 has a value proportional to the deviation between the generator 10 frequency and the set value input, and is passed through the phase control circuit 11 and the ignition circuit 12 to the thyristor 1 so that this becomes the minimum value.
3 firing phases are controlled. That is, when the frequency of all power generators is high, the setting value of the setting device 15 is also high, the frequency of the electric generator 1 is lowered by delaying the firing phase of the thyristor 130 and reducing the current to the variable speed device 2a. Conversely, when the frequency of the generator 10 is lower than the set value, the firing phase of the thyristor 13 is advanced to increase the current to the variable speed device of the motor 1, thereby raising the frequency of the generator 1.

Conventional automatic frequency IN adjustment devices are configured as described above, so if the external frequency setting device is short-circuited or disconnected, its output signal value will become abnormal, and the generator frequency will therefore change. There is a danger that this may lead to serious failures such as power outages or system failures.

172: Since the setting value of the setting device is inputted to the adjustment device at a voltage level, there is a drawback that it is easily influenced by external noise.

This invention eliminates the drawbacks of the conventional devices as described above, and includes a setting device that outputs the set value as a pulse signal, and a setting device that counts the number of pulses of this pulse signal to raise and lower the frequency. To provide an automatic frequency adjustment device which is provided with a set value input circuit for determining the amount, and is configured to maintain the previous frequency by the output of the set value input circuit even when the setter is short-circuited or disconnected. The purpose is

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, the same parts as in FIG. 1 are designated by the same reference numerals, and repeated explanations will be omitted. Reference numeral 16 denotes an arithmetic circuit which freely exchanges signals with an external device (not shown) for purposes such as during automatic synchronization or active power sharing, and also generates data signals. For example, it consists of a microprocessor. 17 is an output circuit that outputs a pulse 17m to be counted up or down according to the data signal supplied from the arithmetic circuit 16 and a control signal 17b4 that specifies the up or down count; the arithmetic circuit 16 and the output circuit IT are a frequency setter; 18. 19 is a counter consisting of an up/down counter that counts according to the pulse 17a from the output circuit 17 and the control signal 17b. 20 is counter 19
A digital converter that converts the count contents into an analog voltage.
It is an analog converter. Analog to digital converter 2
The output signal of 0 is input to the inverting input of the operational amplifier 10 via the resistor 7a.

Next, the busy action will be explained. The arithmetic circuit 16 calculates the set value required at that time from the given data, and based on the calculation result, the output circuit 11 sends a signal to the controller 19 indicating the direction of frequency increase or frequency decrease from the output circuit 17. f′1. When increasing the frequency of the pulse 17a,
That is, when the control signal 17b is 1, it counts up,
Further, in the case of lowering the frequency, that is, when the control signal 17b is O, a down count is performed. This count result is converted into an area-to-analog voltage Kf by a digital-to-analog converter 20, and then inputted to an operational amplifier 10 through a resistor 7. The operational amplifier 10 includes a transformer 5 and a frequency detection circuit 6.
Input via f'L7? : The value of the frequency signal of the generator 1 is compared with the set value inputted from the digital-to-analog converter 20, and the deviation between the two is detected. below,
As described above, the frequency of the output t[ is controlled so that this deviation is minimized.

As described above, if this invention is implemented, the set value for the frequency of the generator is given by the output of the counter, so the set value can be stably obtained, and therefore the reliability of the device can be improved. , and facilitates the interface with automation equipment.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional automatic frequency adjustment device, and FIG. 2 is a circuit diagram of an automatic frequency adjustment device according to an embodiment of the present invention. 1.3...Star II machine, 2...Electric motor, 2a...
- Variable speed device, 5... Transformer, 6... Frequency detection circuit, 10... Operational amplifier, 11... Phase control circuit,
12...Ignition circuit, 13...Sirisk, 14...
・Automatic frequency adjustment circuit, 16... Arithmetic circuit, 11...
- Output circuit, 18... Frequency adder, 19... Counter, 20... Digital-to-analog converter. Agent Masuo Oiwa (7)

Claims (1)

[Claims] +11 Detects the deviation value between a preset frequency setting value and the output frequency of the generator, and automatically adjusts the frequency VB of the generator to control the output frequency of the generator according to this deviation value. The device includes a setting device that outputs a number of pulses corresponding to the frequency setting device, a counter that counts the pulses, and a conversion that converts the counted value of the counter into an analog signal and outputs the frequency setting device. An automatic frequency adjustment device for a generator, characterized by comprising: (21 The counter consists of an up/down counter, and the setter is characterized in that when changing the frequency setter, it supplies a pulse corresponding to the change to the up or down count input of the counter. Claim 1:
Automatic frequency adjustment device for the generator described in Section 2.