JPH0767368A - Starter for synchronous machine - Google Patents

Abstract

PURPOSE:To realize a stable speed control by reducing an output torque of a starter even under an operating state where the resisting torque of a synchronous machine is relatively small. CONSTITUTION:This is a start controller equipped with a speed regulator 18 outputting a current reference signal Ir based on the deviation between a frequency signal fs and its target value of a synchronous machine 6, a current regulator 20 outputting a phase control signal to a forward converter pulse generator 21 based on the deviation between a current signal Is and Ir of a current detector 19, and a margin of angle controller 23 outputting a phase control signal thetar2 to a reverse converter pulse generator 24 in such a manner that fs, Is and reverse converter output voltage are input and the margin of angle of a reverse converter 4 becomes equal to a set point gamma2 of the margin of angle. Also provided are a reverse converter leading angle controller 31 outputting a leading angle control signal thetabeta based on Ir, and a phase lead selection circuit 32 which inputs thetabeta and thetar2, select a signal with a more advanced phase and outputs it to the forward converter pulse generator 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter for a synchronous machine such as a synchronous generator or a synchronous motor.

[0002]

2. Description of the Related Art A conventional example of a starter for a synchronous machine is shown in FIG.

In FIG. 5, the starting device power supply V _ss is supplied to the synchronous machine 6 via an input transformer 1, a forward converter 2, a DC reactor 3, an inverse converter 4 and an AC reactor 5.
The forward converter 2 and the inverse converter 4 are three-phase rectifiers each composed of a thyristor element. Further, the synchronous machine 6 has a field winding 7, and a speed pulse generator 8 is provided on the shaft. Further, the primary side of the input transformer 1 is provided with a transformer 9 for detecting the power supply phase, and the output end of the synchronous machine 6 is provided with a transformer 10 for detecting the output voltage V _s and the phase thereof. A current transformer 11 is provided on the AC side of the forward converter 2 to detect a current.

On the other hand, the field winding 7 of the synchronous machine 6 is applied with a field voltage obtained by rectifying the excitation power source V _sf supplied through the excitation transformer 12 by the thyristor rectifier 13, and the field current I _F is generated. Flowing. Further, a transformer 14 for detecting a phase is provided on the primary side of the excitation transformer 12, and the thyristor rectifier 1
Current transformers 15 are provided on the AC side of 3 to detect current.

Further, as the starting control device 16, a speed detector 17, a speed regulator 18, a current detector 19, a current regulator 20, a forward converter pulse generator 21, a voltage detector 22,
An allowance angle controller 23 and an inverse converter pulse generator 24 are provided, and the speed detector 17 inputs a pulse having a frequency proportional to the rotation speed of the synchronous machine 6 output from the speed pulse generator 8 to the synchronous machine. Output the frequency signal f _s . Speed regulator 1
8 receives the synchronous machine frequency signal f _s and the frequency setting value f _r, and outputs a current reference signal I _r and amplifies the deviation. The current detector 19 rectifies the AC output of the current transformer 11 and outputs a current signal I _s . The current regulator 20 uses the current reference signal I
_r and the current signal I _s are input, the deviation signal is amplified, and the forward converter phase control signal θ _r1 is output. The forward converter pulse generator 21 receives the starting device power supply V _ss via the transformer 9 to detect the power supply phase θ ₁ and also receives the forward converter phase control signal θ _r1 to correspond to θ ₁ . The firing pulse signal P ₁ is sequentially output to each thyristor element of the forward converter 2 at a timing. Further, the voltage detector 22 inputs an AC output from the output end of the synchronous machine 6 via the transformer 10, rectifies it, and outputs an inverse converter voltage signal V ₂ . Margin angle controller 23, the synchronous machine frequency signal f _s and the current signal I _s and inverter voltage signal V
₂ and the margin angle set value γ ₂ are input, and the inverse converter phase control signal θ _{r2 in} which the commutation overlapping angle of the inverse converter 4 is taken into consideration for the margin angle set value γ ₂ is output. Inverse converter pulse generator 24
Receives the AC output of the transformer 10, detects the synchronous power supply phase θ ₂ at the output end of the synchronous machine 6, inputs the inverse converter phase control signal θ _r2, and performs inverse conversion at the timing corresponding to θ _r2. The firing pulse signal P ₂ is sequentially output to each thyristor element of the container 4.

On the other hand, an excitation controller 25 having the following components is provided. That is, the field current setting device 2
6 outputs a predetermined field current set value I _fr when the synchronous machine 6 is started. The field current detector 27 inputs and rectifies the AC output of the current transformer 15, and outputs a field current signal _If . The field current regulator 28 controls the field current setting value I _fr and the field current signal I.
_f is input, the deviation signal is amplified, and the exciter device phase control signal θ _rf is output. The pulse generator 29 is the transformer 14
Of the excitation power supply phase θ _f , the excitation device phase control signal θ _rf is input, and the firing pulse P _f is sequentially applied to each thyristor element of the thyristor rectifier 13 at the timing corresponding to θ _rf. Output.

The operation of the starting device when accelerating the synchronous machine 6 in the above-described structure will be described.

A predetermined field current I _F is supplied to the field winding 7 according to the field current setting value I _fr . At this time, an output voltage V _s proportional to the field current I _F and the frequency f of the synchronous machine 6 is induced in the synchronous machine 6. The inverse converter 4 performs an inverter operation by using the output voltage V _s as a power source and sends electric power from the starting device power source V _ss to the synchronous machine 6.

At this time, the inverse converter 4 is operated by the margin angle controller 23.
By this, even if the converter current I _d , the output voltage V _s , and the frequency f change, the margin angle is controlled so as to be the margin angle set value γ _2, and the high power factor operation is performed in a range where commutation failure does not occur.
On the DC side of the inverse converter 4, a DC voltage V _DC2 corresponding to the output voltage V _s and the inverse converter phase control signal θ _r2 appears.
_{For DC2} , the current regulator 20 adjusts the phase control signal θ _r1 of the forward converter 2 so that the converter current I _d matches the current reference signal _If, and controls the forward converter DC voltage V _DC1 . .
The speed regulator 18 increases or decreases the current reference signal I _r so that the synchronous machine frequency signal f _s matches the frequency set value _fr, and maintains the synchronous machine 6 at a predetermined frequency.

In FIG. 5, the input transformer 1 is for converting the voltage level and for protecting the thyristor element of the forward converter 2 from a short circuit current, and the DC reactor 3 is for suppressing the ripple of the starting device current I _d. The AC reactors 5 are provided to protect the thyristor elements of the inverse converter 4 from short-circuit current.

When the synchronous machine 6 is started by the static starter as described above, conventionally, a constant field current is supplied to the field winding 7 of the synchronous machine 6 regardless of the operating state of the starter. .

[0012]

However, the above-mentioned conventional starting device has the following problems.

The output torque T of the starter is expressed by the following equation [Equation 1], and if the commutation overlap angle of the inverse converter 4 is ignored, the output voltage V _s of the synchronous machine 6 and the converter set current I _{d are shown.} , And the cosine of the margin angle γ of the inverse converter 4, and inversely proportional to the frequency of the synchronous machine 6.

[0014]

[Number 1] T = (wherein, K: proportionality _{constant) K · V s · I d} · cos γ / f in the conventional starting device, the field current setting value I _fr does not depend on the operating state of the starting device constant Since it is a value of V _s / f which is proportional to the field current of the synchronous machine 6,
Is constant, and the margin angle γ of the inverse converter 4 is also controlled to a constant margin angle setting value γ _2. Therefore, the output torque T of the starting device was proportional to the converter current I _d .

On the other hand, the converter current I _d includes voltage ripples of the DC voltages V _DC1 and V _DC2 of the forward converter 2 and the inverse converter 4 and a current ripple corresponding to the inductance of the DC reactor 3. If the converter current is interrupted due to this current ripple, stable control cannot be performed. Therefore, a lower limit is set for the normal current reference signal I _r to prevent the converter current I _d from being interrupted.

Therefore, there is a certain lower limit value in the output torque of the starter, and in the operating state in which the reaction torque of the synchronous machine 6 is smaller than the minimum output torque of the starter, the frequency f of the synchronous machine 6 is kept constant by the starter. Could not control.

The present invention has been made in consideration of such a point, and provides a starting device that reduces the output torque and realizes stable speed control even in an operating state where the reaction torque of the synchronous machine 6 is relatively small. The purpose is to do.

[0018]

That is, the present invention relates to a forward converter for converting alternating current to direct current, and an inverse converter for converting direct current output of the forward converter into alternating current power having a variable frequency and supplying the alternating current power to a synchronous machine. In a synchronous machine starting device provided with a control means for adjusting the output current of the inverse converter to control the rotation speed of the synchronous machine, when the output current becomes a predetermined value or less, the output phase of the inverse converter Is provided for controlling the rotation speed of the synchronous machine.

The present invention further includes a forward converter for converting alternating current to direct current, an inverse converter for converting direct current output of the forward converter into alternating current power having a variable frequency and supplying the synchronous machine, and an inverse converter for the inverse converter. In a synchronous machine starting device provided with a control means for adjusting the output current to control the rotational speed of the synchronous machine, when the output current becomes a predetermined value or less, the field current of the synchronous machine is adjusted to perform the synchronization. A field current adjusting means for controlling the rotation speed of the machine is provided.

[0020]

In the former configuration of the present invention, when the starting device is required to have the minimum output, the margin angle γ is increased by increasing the control advance angle of the inverse converter. It is possible to reduce cos γ in [Equation 1]. Therefore, even in an operating state in which the reaction torque is small, it is possible to stably control the speed of the synchronous machine without interrupting the converter current.

In the latter configuration, the field current I _{F of the} synchronous machine is used when the starting device is required to have the minimum output.
By reducing the output voltage-frequency ratio V _s / f, which is proportional to the field current I _F , the output torque can be reduced without interrupting the converter current.
The constant speed control of the synchronous machine can be stably performed even in an operating state where the reaction torque is small.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those in the conventional example are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 1 shows a starting device according to a first embodiment of the present invention. The difference from the conventional example is that a starting control device 16 'is provided.
In addition to the configuration of the starting control device 16 of the conventional example, an inverse converter lead angle controller 31 and a phase lead selection circuit 32 are provided. Inverse converter lead angle controller 31 and phase lead selection circuit 3
Reference numeral 2 corresponds to the phase adjusting means according to claim 1 of the present invention.

The inverse converter lead angle controller 31 receives the current reference signal I _r output from the speed adjuster 18 and outputs a lead angle control signal θ _β . For example, as shown in FIG.
Two comparators 33 and 34, which respectively compare with the set value,
It is composed of an integrator 35 for integrating the comparator output and a limiter 36 for limiting the integrator output within a predetermined range. In FIG. 2, the comparator 33 compares the current reference signal I _r with the lead angle increase setting value I _L1, and when I _r ≤I _L1 , S _1U = 1 and I _r > I
_{When L1} , the lead angle increasing signal _S1U with _S1U = 0 is output. The comparator 34 compares the current reference signal I _r with the lead angle reduction set value I _L2, and when the current reference signal I _r ≧ I _L2 , S _1D = 1 and I _r <
When I _L2 , the lead angle reduction signal S _1D with S _1D = 0 is output. The integrator 35 has a lead angle increasing signal S _1U and a lead angle decreasing signal S _1D.
Input, and output β at a predetermined rate of change when S _1U = 1. _Is increased, and when S _1D = 1, the output β is output at a predetermined change rate. To reduce. The limiter 36 outputs the integrator output β. Is input, and the advance angle control signal θ _β is output with a limit set by a predetermined upper and lower limit value.

Here, the lead angle increase set value I _L1 is the lower limit value of the current reference signal I _r , and the lead angle decrease set value I _L2 can be any value slightly larger than I _L1 . Also, the integrator 3
The output change rate of 5 is a value considering the stability of the control system, the lower limit of the limiter 36 is a margin angle setting value γ ₂ , and the upper limit is a lead angle required according to the controlled object.

The phase lead selection circuit 32 includes a margin angle controller 2
The output θ _{r2 of} 3 and the output θ _β of the inverse converter lead angle controller 31 are input, and a signal with a more advanced phase is selected and output to the inverse converter pulse generator 24 as an inverse converter phase control signal θ _r3. To do.

Next, the operation of the embodiment having the above structure will be described.

The frequency setting value f _r becomes smaller than the frequency f of the synchronous machine 6, when the current reference signal I _r is the output resulting speed regulator 18 is the lower limit value I _L1, inverter lead angle controller 31 At the input of the integrator, the advance angle increase signal S _1U = 1
And the integrator output β. Increases at a predetermined rate of change. Therefore, the lead angle control signal θ _β, which is the output of the inverse converter lead angle controller 31, increases, so that the phase lead selection circuit 32 selects the lead angle control signal θ _β and sets it as the inverse transformer phase control signal θ _r3. Output to the inverse converter pulse generator 24.
As a result, the control advance angle β of the inverse converter becomes large, and therefore the margin angle γ also becomes large.
The output torque T of the starter becomes smaller.

In this way, the frequency f of the synchronous machine 6 changes in the decreasing direction due to the decrease of the output torque T, and the frequency setting value f
_{Below r} , the speed regulator 18 increases the current reference signal I _r . At this time, since I _r > I _L1 ,
The lead angle control signal θ _β stops increasing and the current reference signal I _r
The output torque T increases in proportion to.

Further, for acceleration of the synchronous machine 6, I _r ≧ I _L2
Then, the lead angle decrease signal of the integrator input becomes S _1D = 1 and the control lead angle β of the inverse converter 4 decreases and the output torque T increases in accordance with the lead angle control signal θ _β . And
When the lead angle control signal θ _β becomes equal to or less than the output θ _r2 of the margin angle controller 23, the output phase of the inverse converter 4 is controlled to the margin angle set value γ ₂ by the output θ _r2 of the margin angle controller 23.

That is, in a driving state in which the output torque T is small such that the constant speed control cannot be performed with the predetermined margin angle setting value γ ₂ , the current reference signal I _r is finally I _L1 <I _r <.
The lead angle control signal θ _β is adjusted to the range of I _L2 and has a lead phase from the output θ _r2 of the margin angle controller 23.

From this state, the frequency set value _fr increases,
When the synchronous machine 6 is re-accelerated, the current reference signal I _r increases, the lead angle control signal θ _β decreases, and the output phase of the inverse converter is controlled to be constant by the output θ _r2 of the margin angle controller 23. By doing so, the synchronous machine 6 accelerates at the maximum output of the starting device.

As is clear from the above description, according to the above-described embodiment, the output of the inverse converter 4 can be obtained even in the operating state where the reaction torque of the synchronous machine is small, in which stable speed control cannot be performed by adjusting the converter current. By controlling the phase, the output torque of the starting device can be reduced and stable speed control can be realized.

FIG. 3 shows the starting device of the second embodiment of the present invention. The difference from the conventional example is that the current output from the speed regulator 18 is added to the structure of the starting control device 16 of the conventional example. The starting control device 16 ″ is provided with the excitation amount controller 41 that changes the field current setting value based on the reference signal I _r . The excitation amount controller 41 is the field current according to claim 2. It constitutes an adjusting means.

In FIG. 3, the excitation amount controller 41 inputs the current reference signal I _r from the speed regulator 18, and outputs the field current decrease signal S _2D or the field current increase signal S _2U according to the value of I _r. Output to the field current setting device 26. S _2D and S _2U are logic signals having a value of either 0 or 1. The field current setter 26 uses the field current decrease signal S _2D and the field current increase signal S _{2D.
When 2U} is input and S _2D = 1, the field current setting value I _fr
Is reduced at a constant rate of change, and when S _2U = 1 the field current setting value I _fr is increased at a constant rate of change and output.

An example of the excitation amount controller 41 is shown in FIG. The excitation amount controller 41 is composed of two comparators 42 and 43 that compare the current reference signal I _r with different set values. The comparator 42 uses the current reference signal I _r as the excitation decrement setting value I _L3
Comparison, and outputs the _{S 2D = 1, I r>} S 2D = 0 field current decrease signal S _2D when the I _L3 when I _r ≦ I _L3 and. Comparator 4
3 compares the current reference signal I _r with the excitation increase setting value I _L4 ,
A field current increase signal S _2U of S _2U = 1 when _r ≧ I _L4 and S _2U = 0 when I _r <I _L4 is output.

Here, the excitation decrease set value I _L3 is the lower limit value of the current reference signal I _r , and the excitation increase set value I _L4 can be any value a little larger than I _L3 . Further, the rate of change of the field current setting value I _fr of the field current setting device 26 is a value in consideration of the stability of the control system, and I _fr is provided with appropriate upper and lower limits.

Next, the operation of the embodiment having the above structure will be described.

The frequency setting value f _r becomes smaller than the frequency f of the synchronous machine 6, when the result is the output of the speed regulator 18 current reference signal I _r becomes its minimum value as, the maximum Excitation down set value I _L3 The excitation amount controller 41 outputs a field current decrease signal S _2D = 1 and a field current increase signal S _2U = 0. Along with this, the field current setting value I _fr gradually decreases, and the field current I _F of the synchronous machine 6 decreases. Therefore, the ratio V _s / of the output voltage V _s of the synchronous machine 6 and the frequency f proportional to I _F. f also decreases, and the output torque T of the starting device decreases from the formula [Equation 1].

The frequency f of the synchronous machine 6 is reduced due to a decrease in the output torque T, it becomes smaller than the frequency set value f _r,
The speed regulator 18 increases the current reference signal I _r . At this time, since I _r > I _L3 , S _2D = 0 and the field current I
_Since the decrease of _F stops, the output torque T of the starting device is I _r
Increases in proportion to.

When I _r becomes equal to or more than the excitation increase set value I _L4 due to the acceleration of the synchronous machine 6, the excitation amount controller 41 outputs the field current increase signal S _2U = 1. Along with this, the field current I of the synchronous machine 6
_F increases and the output torque T increases further.

As a result, at a predetermined field current setting value I _fr , the minimum output torque of the starter exceeds the reaction torque and the frequency f of the synchronous machine 6 is finally set at the operating point where constant speed control cannot be performed. When it matches the value f _r ,
The current reference signal I _r falls within the range of I _L3 <I _r <I _L4 , and the field current setting value I _fr of the synchronous machine 6 is below a predetermined value at this time.

From this state, the frequency setting value _fr increases,
When the synchronous machine 6 is re-accelerated, the current reference signal I _r increases and the field current I _F returns to a predetermined value, so that the starting device supplies the maximum output to the synchronous machine 6.

As is clear from the above description, according to the above embodiment, the field current I _F of the synchronous machine 6 is increased or decreased according to the current reference signal I _r of the speed regulator 18, so that the synchronous machine 6 The field current I in an operating state in which the reaction torque of is relatively small
By reducing _F , the constant frequency operation of the synchronous machine 6 can be stably performed. Further, when accelerating the synchronous machine 6, the field current I _F can be increased to a predetermined value to accelerate the synchronous machine 6 with the maximum output of the starting device.

[0045]

As described above, according to the present invention,
It is possible to reduce the minimum output of the starting device as compared with the related art. As a result, even if the reaction torque of the synchronous machine is relatively small, the effect that the constant frequency control of the synchronous machine can be stably performed is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a starting device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of an inverse converter lead angle controller according to the present invention.

FIG. 3 is a block diagram showing a starting device of a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration example of an excitation amount controller according to the present invention.

FIG. 5 is a block diagram showing a conventional example of a starting device.

[Explanation of symbols]

 2 ... Forward converter 4 ... Inverse converter 6 ... Synchronous machine 7 ... Field winding 8 ... Speed pulse generator 16, 16 ', 16 "... Start control device 18 ... Speed regulator 20 ... Current regulator 21 ... Forward converter pulse generator 23 ... Margin angle controller 24 ... Inverse converter pulse generator 25 ... Excitation controller 26 ... ...... Field current setting device 31 ...... Inverter lead angle controller 32 ...... Phase lead selection circuit 33, 34, 42, 43 ...... Comparator 35 ...... Integrator 36 ...... Limiter 41 ... Excitation amount controller

Claims (2)

[Claims] 1. A forward converter for converting alternating current into direct current, an inverse converter for converting direct current output of the forward converter into alternating current power having a variable frequency and supplying it to a synchronous machine, and an output current of the inverse converter. In a synchronous machine starting device having a control means for adjusting and controlling the rotational speed of the synchronous machine, when the output current becomes equal to or less than a predetermined value, the output phase of the inverse converter is adjusted to perform the synchronization. A starting device for a synchronous machine, comprising a phase adjusting means for controlling a rotation speed of the machine. 2. A forward converter for converting alternating current into direct current, an inverse converter for converting direct current output of the forward converter into alternating current power having a variable frequency and supplying the alternating current power to a synchronous machine, and an output current of the inverse converter. In a synchronous machine starting device having a control means for adjusting and controlling the rotational speed of the synchronous machine, when the output current becomes a predetermined value or less, the field current of the synchronous machine is adjusted to adjust the synchronization. A synchronous machine starting device comprising field current adjusting means for controlling the rotation speed of the machine.