CN1076541C - Driving control device of synchro and detecting device for A. C. signal - Google Patents

Abstract

The present invention aims to detect the quantity of electricity accurately even when the frequency of an AC signal is fluctuated. An excitation controller and a voltage detector 1A for the synchronous motor has an amplitude arithmetic means 5, which converts the quantity of electricity detected into a digital signal for a fixed period and into which the converted quantity of electricity is inputted and which outputs the amplitude arithmetic result B of the value of a digital signal D on the basis of the digital signal, and an integral arthmetic means 6 adding the absolute value of the digital signal D by a fixed number and outputting an integral arithmetic result S, and the amplitude arithmetic result B and the integral arithmetic result S are changed and outputted according to the frequency detecting signal F of the AC voltage V0.

Description

Excitation control device and AC signal detection device for synchronous machine

The present invention relates to an alternating current signal detection device and an excitation control device for a synchronous machine. Even when the frequency of the alternating current power changes, the device can still correctly measure the alternating current power such as the output voltage of the synchronous machine connected to the power system. Assays are performed and additionally used for control.

For example, a sine wave AC voltage can be measured by an automatic voltage regulator (hereinafter referred to as AVR) that controls the output voltage of a synchronous machine (generator). The measurement of the AC voltage of the sine wave includes an amplitude calculation method that calculates the amplitude of the voltage, an integral calculation method that calculates the integral value, and a normalization calculation method that converts the analog signal into a DC signal and performs normalization calculation. and so on.

Next, a conventional voltage detection device using an amplitude calculation method will be described with reference to FIG. 20 .

The voltage detecting device 1 is constituted in the following manner, it is composed of an A/D conversion processing unit 2 and an arithmetic processing unit 3, the AC voltage V0 is input into the A/D conversion processing unit 2, and the output of the A/D conversion processing unit 2 is The digital signal matrix D is input to the arithmetic processing unit 3, and the output of the arithmetic processing unit 3 is output from the voltage detection device 1 as a voltage detection signal V1. These structures are described in detail below.

First, in the A/D conversion processing unit 2, the instantaneous value of the AC voltage V0 is converted into a digital signal at a predetermined cycle, and the digital signal matrix D is output as a digital signal at each cycle. The calculation processing unit 3 includes an amplitude calculation unit 5, which calculates the voltage detection signal V1 proportional to the effective value or average value of the AC voltage V0 according to the digital signal matrix D, and outputs it.

As shown in FIG. 21, in the case of an AC voltage V0, the calculation method of the amplitude calculation means 5 follows the following formula ( 1) Perform calculations.

[mathematical formula 1]

B＝K*SQRT|D-32-(D-0*D-6)| Formula (1)

Here, K: A constant that converts the amplitude value to rms or average value

B: Amplitude operation result

D—n: the value of the digital signal matrix D (n times before)

SQRT: square root

Here, Equation (1) where the amplitude of the input voltage is A is represented by Equation (2) below.

[Mathematical formula 2]

B=K*SQRT|(Asin(wt—π/2))2—Asinwt*Asin(wt—π)|Formula (2)

In addition, when the right side of the formula (2) is decomposed using trigonometric functions, it is represented by the following formula (3).

B＝K*A formula (3)

According to formula (3), it is determined that the amplitude calculation result B is proportional to the amplitude value A of the AC voltage V0 and there is no calculation error.

Fig. 22 is an explanatory diagram showing the frequency characteristics of the amplitude subtraction method. When the frequency of the reference frequency F0 and the frequency of the AC voltage V0 that satisfy the condition of the formula (2) change, the voltage detection signal V1 of the amplitude calculation result B follows the diagram. display changes. This method has the characteristic that the voltage detection signal V1 of the amplitude calculation output B decreases when there is little calculation error based on the reference frequency F0 and the frequency changes.

Next, referring to FIG. 23, a voltage detecting device using a conventional integral calculation method will be described.

The voltage detection device of the integral calculation method in FIG. 23 uses the internal mechanism of the calculation processing part 3 in FIG. The output of the conversion processing unit 2 (digital signal matrix D) calculates and outputs the voltage detection signal V1 proportional to the effective value or average value of the AC voltage V0.

The integral calculation means 6 performs calculation according to the following formula (4).

[mathematical formula 3]

Here, L: a constant that converts the integral value to an effective value or an average value

S: Integral operation result

D—n: the value of the digital signal matrix (n times before)

Fig. 24 is a frequency characteristic diagram of the integral operation method. According to this calculation method, the greater the value of the sampling number N relative to the period of the AC signal (when the sampling period is constant, the frequency of the AC voltage V0 decreases), the higher the calculation accuracy.

For example, if the conversion period of the A/D conversion processing unit 2 is 1/12 times of the period of the AC voltage V0, half-period integration operation is performed, and the number of sampling times N is 6. In this case, there is a characteristic that the calculation error (fluctuation width in the figure) is about 1.7%. When the frequency of the reference frequency F0 relative to the AC voltage V0 changes, the half-period integral operation is premised, and the number of sampling N is increased in the lower frequency area, which has higher precision.

Referring to FIG. 25, the voltage detection device adopting the existing normalized operation method will be described below.

In this figure, the voltage detection device 1 includes: a rectification processing unit 9 that converts an AC voltage V0 into a DC voltage V2, a filter 10 that keeps the DC voltage V2 smooth, an A/D conversion processing unit 11, and the A/D conversion processing unit 11. The conversion processing part 11 converts the smoothed DC voltage V3 into a digital signal according to a certain cycle, and then outputs the digital signal matrix D1, and the calculation processing part 3, which compares the effective value of the AC voltage V0 with the digital signal matrix D1 Or the voltage detection signal V1 whose average value is proportional to the relationship is calculated and output. The calculation processing part 3 is composed of a normalization operation mechanism 12. The normalization operation mechanism 12 makes the digital signal matrix D1 become proportional to the effective value or the average value. Signal.

The normalization operation unit 12 performs calculation according to the formula (5).

[mathematical formula 4]

G＝M*D-0 formula (5)

Here, M: a constant that converts the value of the DC voltage into an effective value or average value

G: Standardized operation result

D—n: the value of the digital signal matrix (n times before)

According to the above calculation method, although the AC voltage V0 is rectified and smoothed, and then A/D conversion processing is performed, the rectified waveform of the AC voltage V0 does not contain fluctuations, and the fluctuations that are not removed by the filter appear in the output fluctuation.

Fig. 26 is a frequency characteristic diagram of the normalized operation method, because when the frequency of the input voltage V0 increases relative to the reference frequency F0 through this operation method, the effect of the filter 10 is strengthened, and the fluctuation is reduced, so that the characteristics of high voltage detection accuracy can be obtained .

Here, when comparing the amplitude calculation method, the integral calculation method, and the normalization calculation method, the amplitude calculation method has the highest calculation accuracy near the reference frequency F0. Compared with the number of sampling times N, the accuracy of the integral operation method is outside the vicinity of different reference frequencies F0, and the operation accuracy of the relative amplitude operation method is higher. The normalized calculation method has a higher calculation accuracy than the amplitude calculation method in regions other than the vicinity of the reference frequency F0 where relative filter performance precision is different.

In addition, when comparing the integral operation method with the normalization operation method, when the error in the reference frequency F0 is the same, since the frequency of the integral operation method decreases, the accuracy is higher, and if the frequency of the normalization operation method increases , the accuracy is higher, so it is better to use the integral operation method in the lower frequency, and it is better to use the standardized operation method in the higher frequency.

However, the measurement of the AC voltage using the amplitude calculation method has the following disadvantages. As shown in FIG. 22, when the frequency is the reference frequency F0 of the AC voltage V0, the error caused by the calculation method is small. As the frequency changes, the voltage detection signal V1 generated by the amplitude calculation result B decreases. For example, when the frequency of the AC voltage V0 is 1.5 times the reference frequency F0, the amplitude calculation result B calculated by the amplitude calculation means 5 is 50%. It can also be calculated according to the data of every 90 degrees in the fundamental wave (data D-3 before 3 samples, etc.) as shown in formula (1). When the frequency of the signal to be detected changes, due to the relative 90 degrees Degree of deviation, which will produce a large error.

In addition, the integral calculation method has the disadvantage that errors often occur due to the calculation method having the characteristic that when the frequency of the AC voltage V0 changes, the number of sampling N increases when the frequency is low , with higher precision. It can also adopt the method of accumulating voltage values for a certain period of time and then calculating the average value as shown in formula (4). However, when the frequency changes, the integration range relative to the sine wave changes, so that stable output cannot be performed. This has the disadvantage that when a larger integration range is obtained, stability increases, but conversely, reactivity deteriorates.

Furthermore, the normalized calculation method has the disadvantage that errors are often caused by fluctuations in the input voltage V0 having the characteristic that the effect of the filter 10 increases when the frequency of the input voltage V0 is high , the fluctuation is reduced, and the voltage detection accuracy is high. In addition, the analog circuit including the rectification processing unit 9, the filter 10, etc. is affected by temperature drift or high frequency inside, so the accuracy will not be high.

According to the above method, when an error occurs in the voltage detection, the excitation control device of the synchronous machine with the automatic voltage adjustment device that calculates the control amount by detecting the voltage will also generate an error in the control amount, and the synchronization opportunity will occur. The wrong output voltage will have adverse effects on the power system.

In addition, the following situation will also occur, that is, the output voltage of the synchronous machine is controlled in a region with a large deviation from the basic frequency of the system during the start or stop of the synchronous machine. In addition, the rotation of the synchronous machine during normal operation The frequency will change, so there must be measures to deal with the influence of the frequency of the alternating current.

Therefore, the object of the present invention is to provide a voltage detection device and an excitation control device for a synchronous machine, which can be used even when the frequency of the AC power changes during the detection of the AC power. Under this condition, the effective value or average value of the electric quantity (voltage, current, etc.) can still be detected with high precision, and can be used for control.

(1) The excitation control device of the synchronous machine of the present invention adjusts the excitation device of the excitation circuit of the synchronous machine to control the output voltage of the synchronous machine connected with the AC power system, and the device includes:

An A/D conversion processing mechanism, the A/D conversion processing mechanism inputs the output voltage of the above-mentioned synchronous machine, and converts the instantaneous value of the input power into a digital signal according to a prescribed cycle;

A plurality of arithmetic units, the plurality of arithmetic units use the digital signal output by the above-mentioned A/D conversion processing unit, according to a plurality of calculation methods with different frequency characteristics, for the effective value or average value of the output voltage of the above-mentioned synchronous machine Calculate the power detection signal;

A frequency detection mechanism, the frequency detection mechanism detects the frequency of the output AC power of the synchronous machine;

An output mechanism, which outputs any one of the above-mentioned computing mechanisms as a power detection signal equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine according to the frequency detected by the above-mentioned frequency detection mechanism;

An automatic voltage adjustment mechanism, the automatic voltage adjustment mechanism performs an excitation control calculation based on the electric quantity detection signal output by the above-mentioned output mechanism, and adjusts the output of the excitation control signal sent to the above-mentioned excitation device.

(2) In the above-mentioned first scheme, the above-mentioned multiple computing mechanisms include:

The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of calculating the amplitude of the AC power, is equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine The power detection signal is calculated;

Preliminary computing mechanism, the preliminary computing mechanism adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to at least one of the integral computing method of integrating the AC power or the standardized computing method of standardizing the AC power In the method, the power detection signal corresponding to the effective value or the average value of the output voltage of the synchronous machine is calculated.

(3) In addition, in the above-mentioned (2) aspect, the above-mentioned output means is an output means whose frequency detected by the above-mentioned frequency detection means is within a predetermined range including the fundamental frequency of the AC power in the above-mentioned power system. When it is inside, output the power detection signal sent by the above-mentioned basic calculation mechanism, and output the power detection signal sent by the above-mentioned preliminary calculation mechanism when the frequency detected by the above-mentioned frequency detection mechanism is outside the above-mentioned specified range.

(4) In addition, the excitation control device of the synchronous machine of the present invention adjusts the excitation device of the excitation circuit of the synchronous machine to control the output voltage of the synchronous machine connected with the AC power system, the device includes:

An A/D conversion processing mechanism, the A/D conversion processing mechanism inputs the output voltage of the above-mentioned synchronous machine, and converts the instantaneous value of the input power into a digital signal according to a prescribed cycle;

The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of calculating the amplitude of the AC power, is equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine The power detection signal is calculated;

Preliminary operation mechanism, the preliminary operation mechanism uses the digital signal output by the above-mentioned A/D conversion processing mechanism, according to any one of the integral operation method of integrating the AC power, or the standardized calculation method of the AC power A kind of operation is performed on the power detection signal equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine;

An output mechanism, the output mechanism includes a high-value priority mechanism, the high-value priority mechanism selects a signal with a higher value among each power detection signal output by the above-mentioned basic operation mechanism and the preliminary operation mechanism, and outputs it;

An automatic voltage adjustment mechanism, the automatic voltage adjustment mechanism performs an excitation control calculation based on the electric quantity detection signal output by the above-mentioned output mechanism, and adjusts the output of the excitation control signal sent to the above-mentioned excitation device.

(5) Also, the AC signal detection device of the present invention includes:

A/D conversion processing mechanism, the A/D conversion processing mechanism inputs AC power, and converts the instantaneous value of the input power into a digital signal according to a specified cycle;

A plurality of computing mechanisms, which use the digital signals output by the above-mentioned A/D conversion processing mechanism to perform calculations on the power detection signal equivalent to the effective value or average value of the above-mentioned alternating current power according to a plurality of different computing methods;

a frequency detection mechanism, the frequency detection mechanism detects the frequency of the AC power;

An output unit that outputs any one of the plurality of calculation units as a power detection signal corresponding to the effective value or average value of the AC power based on the frequency detected by the frequency detection unit.

(6) In addition, in the above-mentioned fifth scheme, the above-mentioned multiple computing mechanisms include:

The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation;

Preliminary calculation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the integration calculation method of integrating the AC power, and detects the electric power detection signal equivalent to the effective value or average value of the above-mentioned AC power perform calculations;

(7) Also, in the above-mentioned fifth scheme, the above-mentioned multiple computing mechanisms include:

The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation;

Preliminary calculation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the standardized calculation method of standardizing the AC power, and detects the electric power detection signal equivalent to the effective value or average value of the above-mentioned AC power Perform calculations.

In addition, (8) in the above-mentioned seventh aspect, the above-mentioned preliminary calculation unit is the following calculation unit, and the calculation unit adopts the second A that converts the DC power obtained by rectifying the input power into a digital signal. The digital signal output by the /D conversion processing mechanism is used to calculate the above-mentioned power detection signal.

(9) Also, in the above-mentioned fifth scheme, the above-mentioned multiple computing mechanisms include:

The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation;

The first preparatory operation unit adopts the digital signal output by the above-mentioned A/D conversion processing unit, according to the integral calculation method of performing integral operation on the AC power, and calculates the effective value or average value of the above-mentioned AC power. The power detection signal is calculated;

The second preparatory operation mechanism adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, and uses the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the normalized operation method of performing standardized operation on the alternating current electric quantity, for the effective value or the average value corresponding to the above-mentioned alternating current electric quantity The power detection signal is calculated.

(10) Also, in the above-mentioned schemes (6), (7), and (9), the above-mentioned output mechanism is the following output mechanism. When the specified basic frequency of the electric quantity is within the specified range, the electric quantity detection signal issued by the above-mentioned basic calculation unit is output, and when the frequency detected by the above-mentioned frequency detection unit is outside the above-mentioned specified range, the electric quantity detection signal issued by the above-mentioned preliminary calculation unit is output.

(11) Also, in the above-mentioned (6), (7), (9), and (10) schemes, the above-mentioned output mechanism includes the following switching selection mechanism, and the switching selection mechanism selects switching or switching in a weighted operation mode and outputting each power detection signal output by the above-mentioned multiple computing mechanisms.

(12) The switching selection mechanism of the output mechanism is a switching selection mechanism provided with a predetermined hysteresis width at a switching boundary.

(13) Also, the AC signal detection device of the present invention includes:

A/D conversion processing mechanism, the A/D conversion processing mechanism inputs AC power, and converts the instantaneous value of the input power into a digital signal according to a specified cycle;

A plurality of computing mechanisms, which use the digital signals output by the above-mentioned A/D conversion processing mechanism to perform calculations on the power detection signal equivalent to the effective value or average value of the above-mentioned alternating current power according to a plurality of different computing methods ;

An output mechanism, the output mechanism includes a high-value selection mechanism, the high-value selection mechanism selects the high-value signal in each power detection signal output by the above-mentioned multiple calculation mechanisms, and uses it as the effective value or average value of the above-mentioned AC power Equivalent power detection signal output.

(14) In addition, in the above-mentioned 13th solution, the above-mentioned multiple computing mechanisms include:

The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation;

Preliminary computing mechanism, the preliminary computing mechanism adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to at least one of the integral computing method of integrating the AC power or the standardized computing method of standardizing the AC power In this way, the calculation is performed on the power detection signal corresponding to the effective value or average value of the above-mentioned alternating current power.

Fig. 1 is the structural diagram of the excitation control device of the synchronous machine of the first embodiment of the present invention;

Fig. 2 is the structural diagram of the first embodiment of the voltage detecting device of the present invention;

Fig. 3 is the frequency characteristic diagram of the function generating mechanism arranged in the voltage detecting device in Fig. 2;

Fig. 4 is the frequency characteristic diagram of the function generating mechanism of another embodiment in Fig. 2;

Fig. 5 is the structural diagram of the second embodiment of the voltage detecting device of the present invention;

Fig. 6 is the frequency characteristic diagram of the function generating mechanism arranged in the voltage detection device among Fig. 5;

Fig. 7 is the structural diagram of the 3rd embodiment of the voltage detecting device of the present invention;

Fig. 8 is a frequency characteristic diagram of the function generating mechanism arranged in the voltage detection device in Fig. 7;

Fig. 9 is a frequency characteristic diagram of the function generating mechanism of another embodiment in Fig. 7;

Fig. 10 is a structural diagram of the fourth embodiment of the voltage detection device of the present invention;

Fig. 11 is a frequency characteristic diagram of the function generating mechanism arranged in the voltage detection device in Fig. 10;

12 is a structural diagram of the fifth embodiment of the voltage detection device of the present invention;

Fig. 13 is a structural diagram of the sixth embodiment of the voltage detection device of the present invention;

Fig. 14 is a frequency characteristic diagram of the function generating mechanism arranged in the voltage detection device in Fig. 13;

15 is a structural diagram of the seventh embodiment of the voltage detection device of the present invention;

Fig. 16 is a frequency characteristic diagram of the function generating mechanism arranged in the voltage detection device in Fig. 15;

Fig. 17 is a frequency characteristic diagram of the function generating mechanism of another embodiment in Fig. 15;

Fig. 18 is a structural diagram of the eighth embodiment of the voltage detection device of the present invention;

Fig. 19 is a frequency characteristic diagram of the function generating mechanism arranged in the voltage detection device in Fig. 18;

FIG. 20 is a structural diagram of an existing voltage detection device using an amplitude calculation method;

Fig. 21 is an explanatory diagram of the amplitude calculation method in Fig. 20;

Fig. 22 is a characteristic diagram of the amplitude calculation mode in Fig. 20;

FIG. 23 is a structural diagram of an existing voltage detection device adopting an integral operation mode;

Fig. 24 is a characteristic diagram of the integral operation mode in Fig. 23;

Fig. 25 is a structural diagram of an existing voltage detection device adopting a standardized calculation method;

FIG. 26 is a characteristic diagram of the normalization calculation method in FIG. 25 .

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a block diagram of an excitation control device for a synchronous machine according to a first embodiment of the present invention.

In FIG. 1, the output voltage and output current of the synchronous machine 20 connected to the AC power system are input to the excitation control device 23 as AC power (AC voltage V0, AC current I0) through the transformer PT21 and the converter CT22. The excitation control device 23 has an alternating current signal detection mechanism 1X and an automatic voltage adjustment operation mechanism 24, which performs excitation adjustment calculations, controls the excitation device 25 through the excitation control signal E that constitutes its control amount, and controls the excitation circuit of the synchronous machine. excitation.

The AC signal detection mechanism 1X calculates the electric quantity corresponding to the effective value or the average value of the alternating current signal V0 and/or I0, and outputs the electric quantity detection signal V1 and/or I1. Afterwards, the automatic voltage adjustment calculation unit 24 performs adjustment calculations based on these signals (for example, calculates the control amount so that the deviation between the voltage setting value and the detected value is zero), and outputs the excitation control signal E to the excitation device 25 .

Fig. 2 is a structural diagram of the first embodiment of the AC signal detection mechanism (voltage detection device) of the present invention. In FIG. 2, the voltage detection device 1A is constituted as follows. It is composed of an A/D conversion processing unit 2 and an arithmetic processing unit 3A. The AC voltage V0 is input to the A/D conversion processing unit 2. The A/D conversion processing The output of the unit 2 is input to the arithmetic processing unit 3 as a digital signal matrix D, and the output of the arithmetic processing unit 3A is output as a voltage detection signal V1.

The A/D conversion processing unit 2 converts the instantaneous value of the AC voltage V0 into a digital signal at a fixed cycle, and outputs a digital signal matrix D.

The calculation processing part 3A is a mechanism for calculating and outputting the voltage detection signal V1 according to the digital signal matrix D. The voltage detection signal V1 is proportional to the effective value or average value of the AC voltage V0. The calculation processing part 3A includes: frequency detection Mechanism 4, the detection mechanism 4 outputs the frequency detection signal F proportional to the frequency of the AC voltage V0 according to the digital signal matrix D; the amplitude computing mechanism 5 (basic computing mechanism), the amplitude computing mechanism 5 outputs the value of the digital signal matrix D Amplitude calculation result B; Integral operation mechanism 6 (preparatory operation mechanism), the integral operation mechanism 6 adds the absolute value of the digital signal matrix D according to the prescribed number of times, and outputs the integral operation result S; Function generating mechanism 7, the The function generator 7 outputs a switching signal Q corresponding to the amplitude calculation result B and the integral calculation result S according to the frequency detection signal F; the switching mechanism 8 switches the amplitude calculation result B and the integral calculation result S according to the switching signal Q .

Fig. 3 is a diagram showing the frequency characteristics of the voltage detecting device 1A which is used in the first embodiment of the present invention.

In this figure, the frequency detection signal F is in the frequency range from the minimum switching frequency F1 to the maximum switching frequency F2 with the reference frequency F0 as the center, the function generator 7 outputs a switching signal Q for selecting the amplitude calculation result B, and the switching mechanism 8 will The value of the amplitude calculation result B is output as a voltage detection signal V1.

When the frequency detection signal F is at a frequency less than the minimum frequency F1 or greater than the maximum switching frequency F2, the function generator 7 outputs the switching signal Q in the manner of selecting the integral operation result S, and the switching mechanism 8 uses the value of the integral operation result S as the voltage detection signal V1 output.

According to the above configuration, the amplitude calculation result B can be output in the high-precision frequency range in the amplitude calculation means 5, and the integration calculation result S can be output as the voltage detection signal V1 in the low-precision frequency range. Therefore, even when the frequency of the AC voltage V0 changes relative to the reference frequency F0, voltage detection with high precision can still be performed by switching the arithmetic mechanism.

If the first embodiment is adopted in the manner described above, the following excitation control device for a synchronous machine can be obtained, that is, even if the number of rotations of the synchronous machine changes and the frequency of the output power changes relative to the reference frequency F0, Since the voltage detection signal can be obtained with high precision, the output of the automatic voltage adjustment operation mechanism is also correct, so that the device can still perform high precision control.

In addition, the present invention can also adopt the same structure as the first embodiment, as shown in FIG. 4, in the function generating mechanism 7, the switching signal Q can maintain hysteresis characteristics according to the frequency detection signal F calculated by the frequency detection mechanism 4. .

That is, in the frequency detection signal F, the minimum switching frequencies F3 and F4 and the maximum switching frequencies F5 and F6 around the reference frequency F0 are set in advance. Here, the minimum switching frequency F3 is the frequency at which the amplitude calculation result B is switched to the integral calculation result S, and the minimum switching frequency F4 is the frequency at which the integral calculation result S is switched to the amplitude calculation result B. In addition, the maximum switching frequency F5 is the frequency at which the integral calculation result S is switched to the amplitude calculation result B, and the maximum switching frequency F6 is the frequency at which the amplitude calculation result B is switched to the integral calculation result S.

Since the hysteresis characteristic is maintained between the minimum switching frequencies F3 and F4 and between the maximum switching frequencies F5 and F6, the change of the frequency detection signal F within the above range will not change the switching signal Q of the function generating mechanism 7 .

According to the above structure, in addition to the effect of the first embodiment of the present invention, the effect that even when the frequency detection signal F is in the vicinity of the switching frequency, when it is within the range of the hysteresis characteristic can be obtained , since the switching signal Q does not change, there is no switching between the amplitude calculation result B and the integral calculation result S, which can control the repetition of changes in the calculation output V1 caused by different calculation mechanisms.

Fig. 5 is a structural diagram of a second embodiment of the voltage detection device of the present invention.

In FIG. 5, compared with the embodiment of FIG. 2, the output part of the voltage detection device 1B is different. The same reference numerals are used for the same structures, and their descriptions are omitted here, and only the differences will be described.

The arithmetic processing unit 3B is composed of a function generator 7 and an arithmetic unit 13. The function generator 7 outputs a weighted signal R corresponding to the amplitude calculation result B and the integral calculation result S respectively based on the frequency detection signal F. A weighted signal R is multiplied by the weighted signal R, the amplitude calculation signal B and the integral calculation result S, and these values are added to output the voltage detection signal V1.

Fig. 6 is a frequency characteristic diagram of the voltage detecting device showing the operation of the second embodiment of the present invention.

In this figure, the minimum weighted frequencies F7 and F8 and the maximum weighted frequencies F9 and F10 are set in advance with the reference frequency F0 as the center based on the frequency detection signal. Here, in the range from the minimum weighted frequency F7 to F8, when the frequency detection signal F increases, the weighting signal R is changed such that the weight of the amplitude calculation result B is increased and the weight of the integration calculation result S is decreased.

Also, when the frequency detection signal F increases in the range from the maximum weighted frequency F9 to F10, the weighted signal R is changed such that the weight of the amplitude calculation result B decreases and the weight of the integration calculation result S increases.

According to the above configuration, the voltage detection signal V1 can be obtained after performing weighted addition of the amplitude calculation result B and the integration calculation result S according to the frequency of the AC voltage V0. Therefore, even when the frequency of the AC voltage V0 changes, a calculation result with high precision can still be obtained. In addition, due to the weighted operation, the output will not change discontinuously due to the difference of the operation mechanism.

Fig. 7 is a structural diagram of a third embodiment of the voltage detection device of the present invention. Compared with the embodiment in FIG. 2 where the integral calculation method adopts the preliminary calculation mechanism, the difference of this embodiment is that the standardized calculation mechanism is used as the preliminary calculation mechanism.

In FIG. 7, the voltage detection device 1C includes: an A/D conversion processing part 2, which converts the AC voltage V0 into a digital signal according to a certain cycle, and outputs a digital signal matrix D; a rectification processing part 9, The rectification processing part 9 converts the AC voltage V0 into a DC voltage V2; the filter 10 keeps the DC voltage V2 smooth; Convert the smoothed DC voltage V3 into a digital signal, and output the digital signal matrix D1; the arithmetic processing unit 3C.

In addition, the arithmetic processing unit 3C includes a frequency detection mechanism 4 that outputs a frequency detection signal F proportional to the frequency of the AC voltage V0 based on the digital signal matrix D calculated from the instantaneous value of the AC voltage V0. Amplitude operation mechanism 5 (basic operation mechanism), the amplitude operation result B of the amplitude operation mechanism 5 output digital signal matrix D; standardization operation mechanism 12 (preparation operation mechanism), this standardization operation mechanism 12 makes according to the DC voltage through smoothing process The calculated digital signal matrix D1 becomes a signal proportional to the effective value or average value.

In addition, the output mechanism is composed of a function generating mechanism 7 and a switching mechanism 8. The above-mentioned function generating mechanism 7 outputs a switching signal Q corresponding to the amplitude calculation result B and the normalization calculation result G according to the frequency detection signal F. The switching mechanism 8 is based on the switching signal Q to switch between the amplitude calculation result B and the normalization calculation result G.

Fig. 8 is a frequency characteristic diagram of the voltage detection device showing the operation of the third embodiment of the present invention.

As shown in the figure, according to the frequency detection signal F, in the frequencies from the minimum switching frequency F11 to the maximum switching frequency F12 centered on the reference frequency F0, the function generator 7 outputs a switching signal Q for selecting the amplitude calculation result B, switching The mechanism 8 outputs the value of the amplitude calculation result B as the voltage detection signal V1.

When the frequency detection signal F is below the minimum switching frequency F11 or above the maximum frequency F12, the function generator 7 outputs a switching signal Q for selecting the normalized calculation result G, and the switching mechanism 8 outputs the value of the normalized calculation result G as a voltage detection signal V1.

According to the above configuration, the amplitude calculation result B is selected in the frequency range where the accuracy of the amplitude calculation means 5 is high, and the normalized calculation result G is selected in the frequency range where the calculation accuracy is low, so that the result can be output as the voltage detection signal V1. . Therefore, even when the AC voltage V0 changes, higher precision voltage detection can still be performed by switching the arithmetic mechanism.

In addition, the present invention can have the same structure as the third embodiment, as shown in FIG.

That is, the minimum switching frequency F13 is the frequency at which the amplitude calculation result B is switched to the normalized calculation result G, and the minimum switching frequency F14 is the frequency at which the normalized calculation result G is switched to the amplitude calculation result B.

In addition, the maximum switching frequency F15 is the frequency at which the normalized calculation result G is switched to the amplitude calculation result B, and the maximum switching frequency F16 is the frequency at which the amplitude calculation result B is switched to the normalized calculation result G.

Because the hysteresis characteristic is maintained between the minimum switching frequency F13 and F14 and between the maximum switching frequency F15 and F16, the change of the frequency detection signal F within the above-mentioned range will not cause the switching signal Q of the function generating mechanism 7 to change. It is possible to prevent excessive switching due to frequency changes near the boundary, and to suppress repeated occurrences of changes in the calculation output V1.

Fig. 10 is a configuration diagram of a fourth embodiment of the voltage detection device of the present invention.

In FIG. 10, compared with the embodiment of FIG. 7, the output part of the voltage detection device 1D is different. The same structures use the same symbols, so their descriptions are omitted, and the differences are described here.

The arithmetic processing unit 3D is composed of a function generator 7 and an arithmetic unit 13. The function generator 7 outputs a weighted signal R corresponding to the amplitude calculation result B and the normalized calculation result G based on the frequency detection signal F. R multiplies the weighted signal R, the amplitude calculation result B and the normalization calculation result G, adds these values, and outputs a voltage detection signal V1.

According to the above configuration, an output obtained by weighting the amplitude calculation result B and the normalization calculation means G according to the frequency of the AC voltage V0 is obtained. Thus, when the function is generated in such a manner that more weights are preliminarily assigned to the arithmetic means with less errors, even when the frequency of the AC voltage V0 changes, a highly accurate calculation result can be obtained.

In addition, due to the weighted calculation, the discontinuous change of the output will not be caused by the difference of the calculation mechanism, so that the stable calculation result can be obtained.

Fig. 11 is a frequency characteristic diagram of the voltage detecting device showing the operation of the fourth embodiment of the present invention.

In this figure, the minimum weighting frequencies F17 and F18 and the maximum weighting frequencies F19 and F20 centering on the reference frequency F0 are set in advance. Here, as the frequency increases in the range from the minimum weighting frequency F17 to F18, the weighted signal R changes such that the weight of the amplitude calculation result B increases and the weight of the normalization calculation result G decreases.

In addition, in the range from the minimum weighting frequency F19 to F20, as the frequency increases, the weighting signal R changes such that the weighting of the amplitude calculation result B decreases and the weighting of the normalization calculation result G increases.

As a result, since the output does not vary discontinuously due to differences in the calculation mechanism, stable calculation results can be obtained.

Fig. 12 is a structural diagram of a fifth embodiment of the present invention. The difference between this embodiment and the embodiments shown in Fig. 2, Fig. 5, Fig. 7, and Fig. 10 is that an output mechanism with a high value priority mechanism is adopted.

In FIG. 12, the voltage detection device 1E includes: an A/D conversion processing part 2, which converts the instantaneous value of the AC voltage V0 into a digital signal according to a certain cycle and outputs a digital signal matrix D; a rectification processing part 9. The rectification processing unit 9 converts the AC voltage V0 into a DC voltage V2; a filter 10, the filter 10 keeps the DC voltage V2 smooth; an arithmetic processing unit 3E.

The calculation processing part 3E includes: an amplitude calculation mechanism 5, which outputs the amplitude calculation result B of the digital signal matrix D; a normalization calculation mechanism 12, which converts the digital signal calculated based on the smoothed DC voltage V3 The signal matrix D1 operation process is a signal proportional to the effective value or the average value, and outputs the standardized calculation result G; the high value priority mechanism 14, the high value priority mechanism 14 compares the amplitude calculation result B with the normalization calculation result G, Select the larger one for output.

According to the above configuration, the larger value of the calculation result of the amplitude calculation result B and the normalization calculation result G can be obtained as the calculation output. Since the amplitude calculation mechanism 5 has the highest accuracy near the reference frequency F0 obtained by formula (2), the accuracy decreases and the output decreases as the relative reference frequency changes, so the high-value priority mechanism 14 operates at the frequency with the highest accuracy. Amplitude calculation results can be selected in the range, and normalization calculation results can be selected in other ranges.

In addition, the high value priority mechanism 14 can also obtain the action and effect of reducing the discontinuous change at the switching point due to the difference in the calculation mechanism.

Fig. 13 is a configuration diagram showing the operation of the sixth embodiment of the voltage detection device of the present invention.

Compared with the configuration of FIG. 12, the voltage detection device 1F shown in FIG. 13 is different in that the output of each calculation means is weighted according to the detected frequency.

The calculation processing part 3F includes: a function generating mechanism 7, which outputs a weighted signal R relative to the amplitude calculation result B and the normalized calculation result G according to the frequency detection signal F; The signal R multiplies the weighted signal R with the amplitude calculation result B and the normalized calculation result G; the high value priority mechanism 14, the high value priority mechanism 14 selects the amplitude calculation result B1 obtained after multiplication with the weighted signal R and the normalized calculation result B1. Calculate the larger value in the result G1 and output it.

Fig. 14 is a frequency characteristic diagram of the voltage detection device showing the operation of the sixth embodiment of the present invention.

As shown in the figure, minimum weighting frequencies F21 to 24 and maximum weighting frequencies F25 to 28 centering on the reference frequency F0 are set in advance. Here, F22 is in the frequency range where the weight of the amplitude calculation result B is increased when the frequency is increased from the minimum weighting frequency F21, and F24 is in the frequency range where the weight of the normalization calculation result is decreased when the frequency is increased from the minimum weighting frequency F23.

Also, F26 is in the frequency range where the weight of the normalization calculation result is increased when the frequency is increased from the maximum weighting frequency F25, and F28 is in the frequency range where the weight of the amplitude calculation result B is decreased when the frequency is increased from the maximum weighting frequency F27.

According to the above configuration, in the frequency range from the minimum weighted frequency F21 to the maximum weighted frequency F28, the larger value of the weighted calculation result of the amplitude calculation result B and the normalization calculation result G can be obtained as a calculation output.

In addition, since the amplitude calculation mechanism 5 is at the highest precision near the reference frequency F0 shown in formula (2), as the frequency changes and the precision decreases, the output decreases, so that the high value priority mechanism 14 can pass through the amplitude calculation mechanism 15. The amplitude calculation result is selected for the frequency region where the highest precision calculation is performed, and the normalization calculation result is selected for the other regions.

In addition, through the high value priority mechanism 14, the variation of the discontinuous output at the switching point due to the difference of the arithmetic mechanism is reduced.

Also, in the structure of Fig. 12 and Fig. 13, the embodiment in which the basic operation mechanism adopts the amplitude operation mechanism 15 has been described, and the embodiment in which the preliminary operation mechanism adopts the standard operation mechanism 12 has been described, but as shown in Fig. 2 Show, preparatory operation mechanism also can adopt integral operation mechanism 6. In addition, the preliminary calculation unit may also be a structure that uses the integral calculation unit 6 and the normalization calculation unit 12 at the same time.

Fig. 15 is a structural diagram of a seventh embodiment of the voltage detection device of the present invention.

A voltage detection device 1G shown in FIG. 15 is a combination of the configuration shown in FIG. 2 and the configuration shown in FIG. 7 . That is, the amplitude calculation mechanism 5 is used as the basic calculation mechanism, the normalization calculation mechanism 12 is used as the preliminary calculation mechanism, and the switching mechanism is used as the output mechanism, which has higher precision.

The calculation processing part 3G includes: a frequency detection mechanism 4, which outputs a frequency detection signal F proportional to the frequency of the AC voltage V0 based on the digital signal matrix D calculated from the instantaneous value of the AC voltage; an amplitude calculation mechanism 5 , the amplitude operation mechanism 5 outputs the amplitude operation result B of the digital signal matrix D; the integral operation mechanism 6, the integral operation mechanism 6 adds the absolute value of the digital signal matrix D according to a prescribed number of times, and outputs the integral operation result S; standardized operation Mechanism 12, the standardization operation mechanism 12 makes the digital signal matrix D1 calculated according to the smoothed DC voltage V3 become a signal proportional to the effective value or the average value; the function generating mechanism 7, the function generating mechanism 7 detects according to the frequency The signal outputs the signal for switching the amplitude calculation result B, the integral calculation result S and the normalization calculation result G; the switching mechanism 8 switches the amplitude calculation result B, the integral calculation result S and the normalization calculation result G according to the switching signal.

Fig. 16 is a frequency characteristic diagram of the voltage detecting device showing the operation of the seventh embodiment of the present invention.

In this frequency characteristic diagram, among the frequencies from the minimum switching frequency F29 centered on the reference frequency F0 to the maximum switching frequency F30, the function generator 7 outputs a switching signal for selecting the amplitude calculation result B according to the frequency detection signal F, and the switching mechanism 8 The value of the amplitude calculation result B is output as the voltage detection signal V1.

In addition, when the frequency detection signal F is at a frequency lower than the minimum frequency F29, the function generator 7 outputs a switching signal Q for selecting the integral calculation result S, and the switching mechanism 8 outputs the value of the integral calculation result as a voltage detection signal V1.

In addition, when the frequency detection signal F is at a frequency greater than the maximum frequency F30, the function generator 7 outputs a switching signal for selecting the normalized calculation result G, and the switching mechanism 8 outputs the value of the normalized calculation result G as the voltage detection signal V1.

According to the above-mentioned structure, the amplitude calculation result B is output as the voltage detection signal V1 near the reference frequency F0 with high accuracy of the amplitude calculation structure B, and the minimum frequency F29 where the precision is lowered is lowered. The integral calculation result S is output as a voltage detection signal V2. In addition, the normalized calculation result G is output as the voltage detection signal V1 in a high-frequency range from the maximum frequency F30 at which the accuracy of the amplitude calculation result B decreases.

If the seventh embodiment is adopted as described above, the calculation output can be obtained by switching to one of the amplitude calculation result, the integral calculation result, and the normalization calculation result according to the frequency of the AC voltage V0. Therefore, if the function is generated in such a manner that an arithmetic mechanism with a smaller error is selected in advance, even when the frequency of the AC voltage V0 changes, a highly accurate arithmetic result can still be obtained.

In addition, the present invention can use the same structure as the seventh embodiment. As shown in FIG.

That is, the minimum switching frequencies F31 and F32 and the maximum switching frequencies F33 and F34 around the reference frequency F0 are set in advance. Here, the minimum switching frequency F31 is the frequency at which the amplitude calculation result B is switched to the integral calculation result S, and the minimum switching frequency F32 is the frequency at which the integral calculation result S is switched to the amplitude calculation result S.

Also, the maximum switching frequency F33 is the frequency at which the normalized calculation result G is switched to the amplitude calculation result B, and the maximum switching frequency F34 is the frequency at which the amplitude calculation result B is switched to the normalized calculation result G. Here, hysteresis characteristics are maintained between the minimum switching frequencies F31 and F32 and between the maximum switching frequencies F33 and F34, and changes in the frequency detection signal F within this range will hardly cause the switching signal Q of the function generating mechanism 7 to occur. Variety.

According to the above-mentioned structure, in addition to the effect of the seventh embodiment of the present invention, since even when the frequency detection signal F is in the vicinity of the switching frequency, the switching signal Q does not change when it is in the range of the hysteresis characteristic. Switching, so as to still suppress the repeated occurrence of the change of the operation output V1 caused by the difference of the operation mechanism.

Fig. 18 is a configuration diagram of an eighth embodiment of the voltage detection device of the present invention.

In FIG. 18, the voltage detection device 1H differs from the detection mechanism of the structure of FIG. 15 in that a weighting and addition mechanism is used instead of a switching mechanism.

The arithmetic processing unit 3H is composed of a function generator 7 and an arithmetic unit 13. The function generator 7 outputs weighted signals corresponding to the amplitude calculation result B, the integration calculation result S, and the normalization calculation result G based on the frequency detection signal F. The above-mentioned calculation unit 13 According to the weighted signal R, the weighted signal is multiplied by the amplitude calculation result B, the integral calculation result S and the normalization result G, and then these values are added to output a voltage detection signal.

Fig. 19 is a frequency characteristic diagram of the voltage detecting device showing the operation of the eighth embodiment of the present invention.

In this frequency characteristic diagram, the minimum weighted frequencies F35 and F36 and the maximum weighted frequencies F37 and F38 centered on the reference frequency F0 are preset. Here, F36 is a frequency range in which the weight of the amplitude calculation result B is increased and the weight of the integration calculation result S is decreased when the frequency is increased from the minimum weighted frequency F35 .

In addition, F38 is a frequency region in which the weight of the amplitude calculation result B is decreased and the weight of the normalization calculation result G is increased when the frequency is increased from the maximum weighting frequency F37.

According to the above-mentioned structure, the amplitude calculation structure B is output as the voltage detection signal V1 near the reference frequency F0 where the accuracy of the amplitude calculation result B is high, and the minimum frequency F35 where the precision is lowered is lowered. The integral operation result S is output as a voltage detection signal V1. In addition, the normalized calculation result G is output as the voltage detection signal V1 in a high frequency region from the maximum frequency F38 at which the accuracy of the amplitude calculation result B decreases.

Also, in the frequency region between the minimum frequencies F35 to F36 and between the maximum frequencies F37 and F38, by weighting each operation result, the voltage detection signal V1 is output. In addition, in the structure of FIG. 18, the adding operation mechanism in the output mechanism can also be used as a high value priority mechanism according to the structure of FIG. 13.

In the above description, the operation methods are examples of the amplitude operation method, the integral operation method, and the normalization operation method, so as to obtain the corresponding formulas (1), (4), and (5), but other methods of the same operation method can also be used (For example, the way of frequency error correction is adopted). In addition to voltage and current, active power and reactive power can be detected as the detected electric quantity of alternating current. In addition, it can also be combined with other methods of calculating the effective value or average value of the AC power.

As mentioned above, if the voltage detection devices of the first to eighth embodiments are used as the AC signal detection device in Fig. 1, the following excitation control device for a synchronous machine can be obtained. The correct power level can still be obtained and can be controlled with higher precision.

If the present invention is adopted in the manner described above, since the alternating current signal (voltage, etc.) is calculated by using various calculation methods with different frequency characteristics, the calculation result with higher precision will be output as the power detection signal according to the frequency characteristics, so that it can be obtained The following AC signal detection device and the excitation control device of the synchronous machine can calculate the correct power detection signal even when the frequency of the power to be detected changes, and can compulsively calculate the correct control amount.

In addition, since the amplitude calculation method for calculating the amplitude of the alternating current quantity is used as the basic calculation method, and the integral calculation method or the normalization calculation method is used as the preliminary calculation method, the output of the amplitude calculation method with high precision is particularly used near the fundamental frequency, In the frequency region that deviates from the fundamental frequency, the output of the integral operation method or the normalization operation method is adopted, so that the accuracy is high in a wide frequency band range, and the correct power detection can be performed.

In addition, if a plurality of preliminary calculation methods are provided and the highest region is used according to the frequency characteristic of each calculation method, a greater effect can be expected.

In addition, as an output mechanism, the weighted signal is multiplied by the voltage detection signal of each calculation method according to the frequency detection signal, and each signal obtained is added to form a voltage detection signal, so that the calculation will not be switched The output given by the mechanism can avoid discontinuous changes due to the difference in the output value of the computing mechanism.

In addition, since the output mechanism adopts a high-value priority mechanism, it can avoid discontinuous changes due to the difference in the output value of the arithmetic mechanism. In addition, there is no need to employ a frequency detection mechanism depending on the situation. Also, according to the present invention, since hysteresis is maintained in the switching of the output mechanism, repeated switching near the switching point can be prevented, and the output will not change due to the difference in the voltage detection signal of each computing mechanism, and the output can be Stable and correct voltage detection signal.

Claims (14)

1. an excitation control device, the excitation control device adjusts the excitation device of the excitation circuit of the excitation synchronous machine to control the output voltage of the synchronous machine connected with the AC power system, it is characterized in that the device includes: An A/D conversion processing mechanism, the A/D conversion processing mechanism inputs the output voltage of the above-mentioned synchronous machine, and converts the instantaneous value of the input power into a digital signal according to a prescribed cycle; A plurality of arithmetic units, the plurality of arithmetic units use the digital signal output by the above-mentioned A/D conversion processing unit, according to a plurality of calculation methods with different frequency characteristics, for the effective value or average value of the output voltage of the above-mentioned synchronous machine Calculate the power detection signal; A frequency detection mechanism, the frequency detection mechanism detects the frequency of the output AC power of the synchronous machine; An output mechanism, which outputs any one of the above-mentioned computing mechanisms as a power detection signal equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine according to the frequency detected by the above-mentioned frequency detection mechanism; An automatic voltage adjustment mechanism, the automatic voltage adjustment mechanism performs an excitation control calculation based on the electric quantity detection signal output by the above-mentioned output mechanism, and adjusts the output of the excitation control signal sent to the above-mentioned excitation device. 2. The excitation control device of synchronous machine according to claim 1, is characterized in that, above-mentioned a plurality of computing mechanisms comprise: The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of calculating the amplitude of the AC power, is equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine The power detection signal is calculated; Preliminary computing mechanism, the preliminary computing mechanism adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to at least one of the integral computing method of integrating the AC power or the standardized computing method of standardizing the AC power In the method, the calculation is performed on the power detection signal corresponding to the effective value or the average value of the output voltage of the above-mentioned synchronous machine. 3. The excitation control device of a synchronous machine according to claim 2, wherein the above-mentioned output mechanism is an output mechanism whose frequency detected by the above-mentioned frequency detection mechanism is within the range of the AC power included in the above-mentioned power system. When the basic frequency is within the specified range, output the power detection signal sent by the basic calculation mechanism, and output the power detection signal sent by the preliminary calculation mechanism when the frequency detected by the frequency detection mechanism is outside the specified range. 4. an excitation control device, the excitation control device adjusts the excitation device of the excitation circuit of the excitation synchronous machine to control the output voltage of the synchronous machine connected with the AC power system, it is characterized in that it includes: An A/D conversion processing mechanism, the A/D conversion processing mechanism inputs the output voltage of the above-mentioned synchronous machine, and converts the instantaneous value of the input power into a digital signal according to a prescribed cycle; The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of calculating the amplitude of the AC power, is equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine The power detection signal is calculated; Preliminary operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to any one of the integral operation method for integrating the AC power or the standardized operation method for standardizing the AC power , to calculate the power detection signal equivalent to the effective value or average value of the output voltage of the above-mentioned synchronous machine; An output mechanism, the output mechanism includes a high-value priority mechanism, the high-value priority mechanism selects a signal with a higher value among each power detection signal output by the above-mentioned basic operation mechanism and the preliminary operation mechanism, and outputs it; An automatic voltage adjustment mechanism, the automatic voltage adjustment mechanism performs an excitation control calculation based on the electric quantity detection signal output by the above-mentioned output mechanism, and adjusts the output of the excitation control signal sent to the above-mentioned excitation device. 5. An AC signal detection device, characterized in that the device comprises: A/D conversion processing mechanism, the A/D conversion processing mechanism inputs AC power, and converts the instantaneous value of the input power into a digital signal according to a specified cycle; A plurality of computing mechanisms, which use the digital signals output by the above-mentioned A/D conversion processing mechanism to perform calculations on the power detection signal equivalent to the effective value or average value of the above-mentioned alternating current power according to a plurality of different computing methods; a frequency detection mechanism, the frequency detection mechanism detects the frequency of the AC power; An output unit that outputs any one of the plurality of calculation units as a power detection signal corresponding to the effective value or average value of the AC power based on the frequency detected by the frequency detection unit. 6. The alternating current signal detection device according to claim 5, characterized in that, the above-mentioned multiple arithmetic mechanisms include: The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation; Preliminary calculation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the integration calculation method of integrating the AC power, and detects the electric power detection signal equivalent to the effective value or average value of the above-mentioned AC power perform calculations; 7. The AC signal detection device according to claim 5, characterized in that, the plurality of computing mechanisms include: The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation; Preliminary calculation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the standardized calculation method of standardizing the AC power, and detects the electric power detection signal equivalent to the effective value or average value of the above-mentioned AC power Perform calculations. 8. The alternating current signal detection device according to claim 7, characterized in that, the above-mentioned preparatory calculation mechanism is the following calculation mechanism, and the calculation mechanism adopts the method of converting the DC power obtained by rectifying the input power into digital The digital signal output by the second A/D conversion processing mechanism of the signal is used to calculate the above-mentioned power detection signal. 9. The AC signal detection device according to claim 5, characterized in that, the plurality of computing mechanisms include: The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation; The first preparatory operation unit adopts the digital signal output by the above-mentioned A/D conversion processing unit, according to the integral calculation method of performing integral operation on the AC power, and calculates the effective value or average value of the above-mentioned AC power. The power detection signal is calculated; The second preparatory operation mechanism adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, and uses the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the normalized operation method of performing standardized operation on the alternating current electric quantity, for the effective value or the average value corresponding to the above-mentioned alternating current electric quantity The power detection signal is calculated. 10. The AC signal detection device according to claim 6, 7 or 9, characterized in that, the above-mentioned output mechanism is the following output mechanism. When the specified basic frequency of the electric quantity is within the specified range, the electric quantity detection signal issued by the above-mentioned basic calculation unit is output, and when the frequency detected by the above-mentioned frequency detection unit is outside the above-mentioned specified range, the electric quantity detection signal issued by the above-mentioned preliminary calculation unit is output. 11. The alternating current signal detection device according to claim 6, 7, 9 or 10, characterized in that, the above-mentioned output mechanism includes the following switching and selecting mechanism, and the switching and selecting mechanism selects to switch or switches the above-mentioned multiple Each power detection signal output by an arithmetic mechanism, and output it. 12 . The AC signal detection device according to claim 11 , wherein the switching selection mechanism of the output mechanism is a switching selection mechanism provided with a predetermined hysteresis width at a switching boundary. 13 . 13. An AC signal detection device, characterized in that the device comprises: An A/D conversion processing mechanism, the A/D conversion processing mechanism inputs AC power, and converts the instantaneous value of the input power into a digital signal according to a specified cycle; A plurality of computing mechanisms, which use the digital signals output by the above-mentioned A/D conversion processing mechanism to perform calculations on the power detection signal equivalent to the effective value or average value of the above-mentioned alternating current power according to a plurality of different computing methods ; An output mechanism, the output mechanism includes a high-value selection mechanism, the high-value selection mechanism selects the high-value signal in each power detection signal output by the above-mentioned multiple calculation mechanisms, and uses it as the effective value or average value of the above-mentioned AC power Equivalent power detection signal output. 14. The AC signal detection device according to claim 13, characterized in that, the plurality of computing mechanisms include: The basic operation mechanism, which adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to the amplitude calculation method of operating the amplitude of the AC power, detects the power equivalent to the effective value or average value of the above-mentioned AC power signal operation; Preliminary computing mechanism, the preliminary computing mechanism adopts the digital signal output by the above-mentioned A/D conversion processing mechanism, according to at least one of the integral computing method of integrating the AC power or the standardized computing method of standardizing the AC power In this way, the calculation is performed on the power detection signal corresponding to the effective value or average value of the above-mentioned alternating current power.

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