JP3519200B2 - Excitation controller for synchronous machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excitation control device for providing a synchronous machine linked to an AC system with a function of absorbing a specific order higher harmonic wave superposed on a fundamental wave of the AC system.

[0002]

2. Description of the Related Art As a conventional excitation control device of this type,
There is known a method in which a DC current controlled so that a fundamental wave component in an output voltage of a synchronous machine has a predetermined value is applied to an exciting winding of a synchronous machine which is an object of control.

[0003]

However, in the synchronous machine connected to the power system and controlled by the conventional excitation control device as described above, there is no absorption function for the harmonic current generated in the system, and the synchronous In the armature winding of the machine, a harmonic voltage corresponding to the inflowing harmonic current is generated to distort the output voltage of the machine and also to the other equipment connected to the power system including the synchronous machine. There is a risk that an inversion current due to voltage distortion may flow in and an abnormal state such as overheating or insufficient output may occur in each of these devices.

In view of the above, an object of the present invention is to provide an excitation control device that functions to give a synchronous machine connected to a power system a capability of absorbing a specific order harmonic current generated in the power system. It is a thing.

[0005]

In order to achieve the above object, in the excitation control device for a synchronous machine according to the present invention, 1) the invention of claim 1 is arranged in parallel with a harmonic source in a power system. The three-phase rotary field synchronous machine connected to the lever power system absorbs the fundamental voltage and harmonic current in order to absorb the harmonic current of a predetermined order in the system current at the connection position of the two. An excitation control device for the synchronous machine, which performs a required excitation relating to induction of both harmonic voltages required for the rotation of a synchronous machine rotating shaft that is interlocked with a position of an exciting magnetic pole of the synchronous machine with respect to generation of the harmonic voltage. The phase detection signal and the detection signal of the system current at the connection position as described above are used as its input signals, and the synchronization required to obtain a synchronous machine armature current having the same amplitude as the predetermined order harmonic current and having an antiphase relationship Machine It is assumed that the circuit is configured so that the value of the exciting current is calculated on the basis of the rotation axis rotation phase.

2) According to a second aspect of the present invention, in the excitation control device for a synchronous machine according to the first aspect of the present invention, the calculation of the required value of the synchronous machine excitation current relating to the above harmonic current absorption is performed for the predetermined order harmonic current. Three-phase / two-phase conversion is performed as a three-phase detection signal for three phases as orthogonal two-axis components on the rotational coordinates that rotate at the fundamental wave angular frequency of the power system, and the proportional vector sum of the anti-phase components of each component on these two axes The amplitude is defined by a value, and the rotation coordinate conversion unit performs a harmonic current that rotates on the rotation coordinate at an angular frequency having a difference between the angular frequency of the predetermined harmonic and the order 1.

3) According to a third aspect of the present invention, in the excitation control device for a synchronous machine according to the second aspect, the output signal of the rotary coordinate conversion section is received and both the amplitude and the phase thereof are stored, and
An integral processing unit that corrects the stored signal value by adding both the amplitude and the phase of the conversion unit output signal that are sequentially calculated at predetermined time intervals to the stored value, and the corrected conversion unit. A waveform memory unit for storing a waveform of one cycle of the output signal and reading the stored waveform contents in synchronization with the rotation phase detection signal; and a D / A converter for receiving the output signal of the waveform memory unit. It is assumed that the output signal of this converter is used as the required value of the synchronous machine exciting current for the above harmonic current absorption.

4) According to a fourth aspect of the invention, in the excitation control device for a synchronous machine according to the third aspect, the separation detection of the predetermined order higher harmonic current from the system current detection signal is A / D converted. The system current detection signal and the rotation phase detection signal are input to the Fourier transform unit which performs a required expansion operation with the rotation phase signal as a reference. 5) The invention of claim 5 is the excitation control device for a synchronous machine according to claim 1, wherein a harmonic current of a predetermined order to be absorbed by the synchronous machine is 6n ± 1 with respect to a fundamental wave of the power system.
The next harmonic current is used, and the required excitation current is the 6nth harmonic current.

Incidentally, in general, when the field winding of a three-phase rotary field type synchronous machine is excited by a 6n-order harmonic rotating magnetic field with respect to the fundamental wave angular frequency, 6n ± in the armature winding of the synchronous machine.
A first harmonic is generated. In addition, for the synchronous machine that is connected to the power system and is in a balanced state,
The (n + 1) th harmonic forms a positive rotating magnetic field in the synchronous machine, and the 6n-1th harmonic forms a negative rotating magnetic field in the synchronous machine, and these rotating magnetic fields are generated in the synchronous machine. Seen from the stator (armature) side, 6n + 1 order and 6n−, respectively.
Although it is a primary rotating magnetic field, when viewed from the rotor (rotating field) side, it becomes a rotating magnetic field of 6nth order in the positive or negative direction, respectively, and generates 6nth order higher harmonics in the rotor winding.

Therefore, the 6n + 1 order or 6n-1 order higher harmonics generated in the armature of the synchronous machine by the rotating magnetic field obtained by exciting the field winding of the synchronous machine with the 6nth order harmonic current, 6n applied to the field winding so as to form a harmonic having the same amplitude and opposite phase as the harmonic on the system side
By controlling the amplitude of the second harmonic current and the conduction phase, it is possible to eliminate the 6n ± first harmonics on the system side.

In accordance with the above, the excitation control apparatus according to the present invention excites the field winding of the three-phase rotary field synchronous machine connected to the power system with the harmonic current of the 6nth order and generates it in the armature winding. The 6n ± 1st-order harmonic voltage or current thus generated has the same amplitude as that of the 6n ± 1st-order harmonic voltage or current generated in the system and has a phase opposite to that of the field winding. It controls the energizing harmonic current.

The three-phase / two-phase coordinate conversion of the 6n ± first-order harmonic current on the rotating coordinates rotating at the fundamental wave angular frequency and the calculation of the required harmonic exciting current according to the conversion result are performed. It is performed according to the following arithmetic expressions. now,
The harmonic current components in the power system to be absorbed by the three-phase rotating field synchronous machine are not the 5th and 7th harmonic currents in the case of n = 1 in the above 6n ± 1st harmonic current. ,
The harmonic currents corresponding to the three phases a, b, and c are i _ah , i
_{If bh} and i _ch are respectively defined by the following equation (1).

[0013]

[Equation 1]

Here, I ₅ and I ₇ are the 5th and 7th orders, respectively.
Next, the peak value of each harmonic current, ∠I ₅ and ∠I ₇ , are the phase angles of the currents I ₅ and I ₇ with respect to the corresponding harmonic voltage, and ω is the fundamental wave angular frequency. Further, each of the above harmonic currents i _ah , i _bh , and i _ch is expressed by the following determinant (2) on the coordinates composed of orthogonal d and q axes in the rotating coordinate system that rotates at the fundamental wave angular frequency ω. 3 phase / 2 phase conversion is performed.

[0015]

[Equation 2]

Here, i _dh and i _qh represent the d-axis component and the q-axis component of the current vector converted into the rotating coordinate system, respectively. The origin of the time t in the equation (2) is defined by the d-axis of the rotor (field) of the synchronous machine and the stator (armature) a.
If it is the moment when the phase winding axes coincide with each other, the coordinates are converted according to equation (2) as shown in equation (3).

[0017]

[Equation 3]

The equation (3) can be rewritten as the equation (4).

[0019]

[Equation 4]

Where i _d6 (i _dh , h = 6) and i _q6 (i
_qh and h = 6) respectively indicate the d-axis component and the q-axis component of the sixth harmonic current vector on the rotating coordinate system. on the other hand,
Wherein on rotation coordinates, the d, respectively q both axial components i _fd, generated by the field current i _f to i _fq its d,
The armature current i _g of the synchronous machine, where the q-axis components are i _dg and i _qg , respectively, is given by the following equation (5).

[0021]

[Equation 5]

Here, K is the winding number ratio between the field winding and the armature winding in the synchronous machine. Further, it is assumed that waveform distortion does not occur in the armature voltage of the synchronous machine. Now, in order to absorb the system harmonic currents summarized by the above equation (4) by the synchronous machine, i _dg + i _dh = 0 and i _qg +
According to both relational expressions of i _qh = 0, the following expression (6) should be established.

[0023]

[Equation 6]

That is, if the field winding of the synchronous machine is excited with the sixth harmonic current according to equation (6) as the required current,
It is possible to eliminate the fifth-order and seventh-order harmonic currents in the electric power system as expressed by the equations (1) to (4), in other words, to absorb them by the synchronous machine.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the circuit diagrams of FIGS. In each of the drawings, the same reference numerals are given to constituent elements having the same function. Here, FIG. 1 shows a first embodiment of the present invention according to each of claims 1, 2 and 5, and FIG. 2 shows an embodiment of the present invention according to each of claims 1, 3, 4 and 5. FIG. 6 is a circuit diagram of an excitation control device for forming a 6n-th order harmonic exciting current when the current to be absorbed by the synchronous machine is a 6n ± 1st-order system harmonic current according to the second embodiment. Is.

FIG. 3 is a circuit diagram of the rotary coordinate conversion circuit in FIGS. 1 and 2, FIG. 4 is a circuit diagram of the phase shifter in FIG. 3, and FIG. 5 is a circuit diagram of a fundamental wave forming excitation system. 6 is a general excitation system circuit diagram for a three-phase rotating field type harmonic absorption synchronous machine in which both the fundamental wave excitation system shown in FIG. 5 and the harmonic excitation system shown in FIG. 1 or 2 are integrated, FIG. 7 exemplifies a circuit diagram of an excitation synthesis system by the outputs of both excitation systems.

First, in FIG. 1, 1 is a synchronous machine for absorbing three-phase rotating field type harmonics, 1a is an armature winding in a stator portion of the synchronous machine 1, and 1b is a harmonic wave in a rotor portion of the synchronous machine 1. A field winding for forming a rotating magnetic field. Further, 2 is a power system, and 3 is a harmonic generation source connected to the power system 2.
Note that i _g is the armature current of the synchronous machine 1 and i _h is the output current of the harmonic generation source 3.

Next, reference numeral 4 denotes an excitation control device for forming a 6nth-order harmonic excitation current, which controls the synchronous machine 1, and a rotation phase sensor 6 of a rotary shaft which is interlocked with an exciting magnetic pole position of the synchronous machine 1. The current transformer 7 for detecting the output current of the harmonic generation source 3 uses the detection signals of both sides as its input, and the required 6
It supplies an nth-order harmonic excitation current and is composed of a 6n ± first-order harmonic detector 4a, a rotary coordinate conversion circuit 4b, a 6nth-order harmonic filter 4c, and a power amplifier 4d.

The harmonic detector 4a has a band-pass filtering function for selectively passing both 6n ± 1st harmonic currents in the three-phase output current of the harmonic generator 3 detected by the current transformer 7. When the output state is n = 1, the output state is as shown in Expression (1). In addition, the rotation coordinate conversion circuit 4b
Is composed of an analog multiplier and an adder. The 6n ± 1st order harmonic current in the three-phase output current of the harmonic generation source 3 as expressed by the equation (1) The three-phase / two-phase conversion is performed as a component on the dq2 axes orthogonal to the rotating coordinate system that rotates at the wave angular frequency, and the time in the formula for receiving the sinusoidal phase detection signal from the rotating phase sensor 6 is used. The origin of t is defined as the moment when the d axis of the rotating field of the synchronous machine and the a-phase winding axis of the armature coincide with each other, and equations (2) to (5) are used.
The above calculation is performed (when n = 1), and the result shown in the equation (6) is output with respect to the required synchronous machine exciting current.

The 6n-th order harmonic filter 4c has a band-pass filtering function for selectively passing the required 6n-th order harmonic current at the output of the rotary coordinate conversion circuit 4b shown in equation (6). The output of the harmonic filter 4c is amplified by the power amplifier 4d, becomes a required 6nth-order harmonic excitation current for the synchronous machine 1, and is supplied to the field winding 1b.

The coefficient K in the equation (5) or (6) is selected as an appropriate value by the gain adjustment in the conversion circuit 4b or the power amplifier 4d. As mentioned above, FIG.
In the circuit configuration shown in (1), the absorption control of the 6n ± 1st-order harmonic current by the synchronous machine 1 is a kind of feed which makes the selection amount of the 6n ± 1st-order harmonic current by the harmonic detector 4a a variable set value. This is a forward control, and no confirmation is made as to whether or not the required harmonic absorption in the power system has not been achieved.

Incidentally, FIG. 3 is a circuit diagram of the rotary coordinate conversion circuit 4b, and FIG. 4 is a circuit diagram of the phase shifter shown in FIG. In FIG. 3, PS _{1 to} PS ₉ are phase shifters that form a predetermined phase difference (30 degrees in the figure) between the input and output signals, and MP _{1 to} MP ₆ multiply the input and output 2 signals. The analog multipliers AD ₁ and AD ₂ are analog adders that add between the input and output signals.

The rotary coordinate conversion circuit 4b is constituted by the above-mentioned elements as shown in FIG. 3, and the above-mentioned equations (2) to (5) are used.
According to the calculation, the d-axis component i _d6 and the q-axis component i _{q6 of the} required sixth harmonic current vector are output. Further, in FIG. 4, A ₁ and A ₂ are amplifiers whose input impedance and amplification degree are both extremely large,
An input resistor respectively against the said amplifier A ₁ and A ₂ are R ₁ and R _3, the resistor R ₂ and the combination and the resistor R ₄ of the capacitor C each form a feedback impedance circuit for said amplifier A ₁ and A ₂ An operational amplifier circuit is formed with each of the amplifiers. A predetermined phase difference (30 degrees corresponding to FIG. 3) is generated between the input and output signals by selecting the constants of the resistors and capacitors.

Next, FIG. 2 shows a second embodiment of the present invention, which is the first embodiment of the present invention in the installation position of the current transformer for detecting the harmonic current and the circuit configuration of the excitation controller. This is different from the above-mentioned FIG. 1 showing an embodiment. 2, current transformer 8 is disposed for the detection of the load current i _t obtained by synthesizing the armature current i _g in the output current i _h and synchronous machine 1 of the harmonic source 3.

Reference numeral 5 denotes an excitation control device which controls the synchronous machine 1 as a control target thereof, and detection signals of both the rotational phase sensor 6 and the current transformer 8 of the rotary shaft which interlock with the exciting magnetic pole position of the synchronous machine 1. Is used as an input to supply a required exciting current to the synchronous machine, and the A / D for both the input signals is supplied.
Converter 5f, harmonics detection unit 5g, and rotating coordinate conversion unit 5
h, integration processing unit 5i, waveform memory unit 5m, PLL
Circuit 5j, address counter 5k, D / A converter 5
n and a power amplifier 5p, and in particular, the above-mentioned respective parts 5g, 5h, 5i are processed in a microcomputer.

The harmonic detecting section 5g constitutes a Fourier transform circuit, and the detection signal of the current transformer 8 converted via the A / D converter 5f is converted into a phase signal by the rotary phase sensor 6. the Fourier transform basis functions as a bandpass filter for selectively detecting 6n ± 1-order harmonic current signal in the load current i _t. Further, the rotary coordinate conversion unit 5h includes the rotary coordinate conversion circuit 4 shown in FIG.
It has the same function as b and calculates both the amplitude and the phase of the 6n-th harmonic i _f required for exciting the synchronous machine 1.

Further, the integration processing section 5i stores the data of both the amplitude and the phase of the 6n-th order higher harmonic wave which the rotational coordinate conversion section 5h is currently sending out, and with respect to these stored data,
The data of both the amplitude and the phase, which are sequentially transmitted by the conversion unit 5h thereafter, are added to sequentially correct the data, and the waveform of one cycle of the 6nth harmonic current _if is expressed by the corrected data. It is synthesized according to (6).

The synthesized waveform data from the integration processing unit 5i is written in the waveform memory unit 5m. After that, the address designated by the address counter 5k that is PLL-synchronized with the rotation phase signal from the rotation phase sensor 6 is read from the waveform memory unit and is input to the D / A converter 5n to be converted into an analog waveform signal. Further, the power is amplified by the power amplifier 5p.

Here, the output of the power amplifier 5p becomes a required synchronous machine exciting current and is supplied to the field winding 1b. The coefficient K in the equation (5) or (6)
Is selected as an appropriate value by gain adjustment in the k converter 5h or the power amplifier 5p. As described above, in the circuit configuration shown in FIG. 2, in the 6n ± primary system side harmonic current absorption control by the synchronous machine 1, the integration amount of the unachieved harmonic absorption is zero due to the function of the integration processing unit 5i. The feedback control is continued until.

Next, FIG. 5 is a circuit diagram of an exciting system for forming a DC exciting current for forming the fundamental wave voltage in the synchronous machine 1. In FIG. 5, reference numeral 10 denotes an excitation control device for fundamental wave excitation, which indicates the deviation between the fundamental wave voltage set value by the voltage setter 11 and the fundamental wave output voltage of the synchronous machine 1 detected by the transformer 12 for an instrument. Input to an AVR (automatic voltage regulator), a control command signal output from this AVR is used to perform gate control of, for example, a thyristor forming a mixing bridge to output an excitation voltage V _DC , and this voltage V _DC causes the synchronous machine 1 to operate.
A desired exciting current is supplied to the field winding of the above-mentioned No. 1 to maintain the fundamental wave output voltage of the synchronous machine 1 at the voltage specified by the voltage setting unit 11.

FIG. 6 is a circuit diagram of an exciting system in which both the fundamental wave forming exciting system and the harmonic exciting system for the three-phase rotating field type harmonic absorbing synchronous machine 1 are integrated.
For both excitation systems shown in FIG. 1 or FIG. 2 and FIG.
It shows a state in which a field winding 1c is formed by adding a magnetic excitation synthesizing section 20 and further a three-phase balanced winding provided on the rotor of the synchronous machine 1.

The excitation / synthesis unit 20 receives the choke coil 21 and the harmonic output voltage V _AC0 of the excitation control device 4 or 5 and outputs the output voltage separately to the voltages V _AC1 and V _AC2. And a phase shift capacitor 23 and a resonance capacitor 24, and the output excitation voltage V of the excitation controller 10 is applied to the one-phase winding of the field winding 1c.
_DC is applied through the choke coil 21 and the harmonic output voltage V _AC2 is applied in parallel to the voltage V _DC to the same field winding through the resonance capacitor 24. The circuit configuration is such that the above harmonic output voltage V _AC1 is applied to the remaining two-phase winding of 1c through the phase shift capacitor 23.

FIG. 7 is a circuit diagram of the excitation synthesis system showing the excitation synthesis state by the outputs of both the fundamental wave and the harmonic excitation system corresponding to the excitation synthesis unit 20 in FIG. 6. As shown in FIG. The U-phase winding of the field winding 1c is used as a DC excitation winding for forming the fundamental wave voltage of the synchronous machine 1.
Further, in order to form the 6nth-order harmonic voltage of the synchronous machine 1, the harmonic excitation voltage V _AC2 is applied to the U-phase winding of the field winding 1c via the resonance capacitor 24, and the harmonic excitation voltage V _AC2 is applied.
_AC1 is applied to the series winding of the V-phase winding and the W-phase winding of the field winding 1c via the phase shift capacitor 23.

In the above structure, the choke coil 21 blocks the harmonic voltage V _AC2 from flowing into the DC excitation system,
The resonance capacitor 24 resonates with the U-phase winding reactance of the field winding 1c to minimize the input impedance with respect to the voltage V _AC2 and to avoid a phase delay. _{This is to set AC1} to the phase advanced state of 90 degrees.

Here, the U-phase winding of the field winding 1c and the V-phase-W-phase series winding form an orthogonal state in the magnetic flux forming state, and both windings in this state have 90 degrees. By applying the voltage V _AC2 having a phase difference and the phase-shifted voltage V _{AC1 in} the state of the voltage ratio 1/3 ^1/2 , the field winding 1c forming the three-phase balanced winding rotates the rotation. A rotating magnetic field having a speed of 6 nf is generated, and in response to the rotating magnetic field, a required 6nth harmonic voltage is formed in the armature winding of the synchronous machine 1.

[0046]

According to the present invention, for a three-phase rotary field synchronous machine connected in parallel to a source of harmonics in a power system, the predetermined order in the current of the power system for a three-phase rotary field synchronous machine. Regarding the generation of the harmonic voltage in the excitation control device of the synchronous machine, which performs required excitation for inducing both the fundamental wave voltage and the harmonic voltage required for absorbing the harmonic current so as to absorb the harmonic current: According to the first aspect of the present invention, the rotational phase detection signal of the rotary shaft of the synchronous machine and the system current detection signal are used as its input signals and have the same amplitude as the predetermined order harmonic current and a reverse phase. A circuit for calculating the value of the synchronous machine exciting current required to obtain the related synchronous machine armature current with reference to the rotating shaft rotation phase, and using the calculated harmonic current as the exciting current of the synchronous machine. Make up By so doing, it becomes possible basically to absorb a predetermined order harmonic current in the system current by the synchronous machine through the excitation control, and 2) the synchronous machine exciting current is required as in the invention of claim 2. By performing the calculation of the value as the calculation on the orthogonal two-axis coordinates of the rotation coordinate system that rotates at the angular frequency of the fundamental wave of the power system in the rotation coordinate conversion unit, the required calculation is extremely simplified. 3) According to the invention of claim 3, in the calculation of the required value of the exciting current of the synchronous machine, the output signal of the rotary coordinate conversion unit in claim 2, that is, the required value of the exciting current is a predetermined order by the synchronous machine. The required system harmonic current absorption operation can be performed to an extremely high level by performing the correction processing in the integration processing section until the absorption of the system harmonic current is completed. According to the invention, in the calculation of the required value of the synchronous machine excitation current, the detection of the harmonic current of the predetermined order in the system current is performed by the Fourier transform operation on the microcomputer by the A / D converted signal. It is possible to improve accuracy and downsize the required circuit configuration.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an excitation controller for synchronous machine harmonic excitation showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram of an excitation controller for exciting a harmonic of a synchronous machine according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram of a rotary coordinate conversion circuit in both FIGS. 1 and 2.

FIG. 4 is a circuit diagram of the phase shifter in FIG.

FIG. 5 is a circuit diagram of an excitation control device for exciting a fundamental wave of a synchronous machine.

FIG. 6 is a circuit diagram of an integrated excitation system for a synchronous machine.

FIG. 7 is an excitation / synthesis system circuit diagram for a synchronous machine.

[Explanation of symbols]

1 Harmonic absorption synchronous machine (three-phase rotary field type) 1a Same as above Armature winding (stator section) of synchronous machine 1b, 1c Same as above Field winding of synchronous machine (rotor section) 2 Power system 3 Harmonics Source 4 Excitation control device (for harmonic excitation) 4a 6n ± 1st-order harmonic detector 4b Rotation coordinate conversion unit 4c 6n-order harmonic filter 4d Power amplifier 5 Excitation control device (for harmonic excitation) 5f A / D conversion Part 5g 6n ± first harmonic detector (Fourier transform unit) 5h Rotation coordinate conversion unit 5i Integration processing unit 5j PLL circuit 5k Address counter 5m Waveform memory unit 5n D / A conversion unit 5p Power amplifier 6 Rotational phase sensor 7 Current transformation Transformer 8 Current transformer 10 Excitation control device (for fundamental wave excitation) 11 Voltage setting device 12 (for instrument) Transformer 13 (for excitation power supply) Transformer 20 Excitation combiner 21 Choke coil 22 Output transformer 23 Phase shift capacitor 2 Resonant capacitor A amplifier (A _1, A ₂₎ AD adder (AD _1, AD ₂₎ AVR automatic voltage regulator PS phase shifter (PS ₁ ~PS ₉₎ MP multiplier (MP ₁ ~PS ₆₎

Front page continued (72) Inventor Hira Yoshiyuki, Tanabe Shinden 1-1 Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Inventor Atsushi Ashizawa 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (56) Reference JP-A-5-336665 (JP, A) JP-A-5-49172 (JP, A) JP-A-5-299972 (JP, A) JP-A-5-137400 ( JP, A) JP-A-5-292718 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02P 7/63 G05F 1/70 H02J 3/01 H02P 21/00

Claims (5)

(57) [Claims] 1. A three-phase rotary field synchronous machine connected in parallel with a harmonic generation source in a power system to a three-phase rotary field synchronous machine, and a predetermined order harmonic in the system current at the connection position of these two. An excitation control device for the synchronous machine, which performs required excitation for inducing both a fundamental voltage and a harmonic voltage required for absorbing a harmonic current so as to absorb a current, and a direct current excitation for generating a fundamental voltage. The basics of forming an electric current
Excitation system for wave formation and harmonic current generation for harmonic voltage generation
Exciting synthesizer that integrates both of
And, regarding the generation of the harmonic voltage, a rotation phase detection signal of the synchronous machine rotating shaft that is interlocked with the position of the excitation magnetic pole of the synchronous machine, and a detection signal of the system current at the connection position as described above, as its input signal. None, a circuit for calculating the value of the synchronous machine exciting current required to obtain the synchronous machine armature current having the same amplitude as the above-mentioned predetermined order harmonic current and having an antiphase relationship with reference to the rotary shaft rotation phase. An excitation control device for a synchronous machine characterized by being configured. 2. The excitation control device for a synchronous machine according to claim 1, wherein the required value of the synchronous machine excitation current relating to the harmonic current absorption is calculated by detecting the three-phase detection signal of the predetermined order harmonic current as the electric power. Three-phase / two-phase conversion is performed as orthogonal two-axis components on the rotational coordinates that rotate at the fundamental wave angular frequency of the system, and the amplitude is taken as the amplitude of the proportional value of the vector sum of the anti-phase components of each component on these two axes. Is performed in the rotating coordinate conversion unit as a harmonic current rotating at an angular frequency having a difference between the angular frequency of the predetermined order harmonic and the first order in the excitation control device of the synchronous machine. 3. The excitation control device for a synchronous machine according to claim 2, wherein the output signal of said rotary coordinate conversion unit is received and both its amplitude and phase are stored, and this stored value is stored at predetermined time intervals. An integration processing unit that corrects the signal storage value by adding both the amplitude and the phase of the conversion unit output signal that are sequentially calculated, and the waveform of one cycle of the corrected conversion unit output signal is stored. And a D / A for receiving the output signal of the waveform memory unit whose waveform storage content is read out in synchronization with the rotation phase detection signal.
A converter is provided, and the excitation signal control device for a synchronous machine is characterized in that the output signal of the converter is used as a required value of the synchronous machine excitation current for the above harmonic current absorption. 4. The excitation control device for a synchronous machine according to claim 3, wherein the separation detection of the predetermined order higher harmonic current from the system current detection signal is rotated with the A / D converted system current detection signal. An excitation control device for a synchronous machine, characterized in that a phase detection signal is input to a Fourier transform unit which performs a required expansion operation with reference to the rotational phase signal. 5. The excitation control device for a synchronous machine according to claim 1, wherein the predetermined-order harmonic current to be absorbed by the synchronous machine is a 6n ± 1st-order harmonic current with respect to the fundamental wave of the power system, The excitation control device for a synchronous machine is characterized in that the required excitation current of is a 6n-order harmonic current.