JP2924424B2 - Automatic voltage regulator for brushless synchronous generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic voltage regulator for a brushless synchronous generator.

[0002]

2. Description of the Related Art The applicant of the present invention first supplies a main generator including a rotor having a main field winding and a stator having a main armature winding, and supplies an exciting current to the main field winding. A main exciter having a rotor having an armature for the main exciter and a stator having a field winding for the main exciter, and a sub generator comprising a magnet generator for supplying an exciting current to the field winding for the main exciter. We proposed a brushless synchronous generator with an exciter and a common rotating shaft.

FIG. 7 shows the configuration of the previously proposed brushless synchronous generator 1. In FIG. 7, reference numeral 2 denotes a rotor 3 having a main field winding 4 and a fixed member having a main armature winding 6. This is the main generator composed of the child 5. Reference numeral 8 denotes a main unit including a rotor 9 having a main exciter armature 10 for supplying an exciting current to the main field winding 4 via a rectifier circuit 11 and a stator 12 having a main exciter field winding 13. Exciter. Also 15
Is a sub-exciter, which is a magnet generator having a magnet rotor 16 and a power generating coil 17 for supplying an exciting current to the field winding 13 for the main exciter. Main generator 2
The main exciter 8 and the sub-exciter 15 have a common rotating shaft, and the brushless synchronous generator 1 is constituted by these.

[0004] Reference numeral 18 denotes an automatic voltage regulator used together with the brushless type synchronous generator 1, which detects an output voltage of the main generator 2 and generates a power generation coil of a sub-exciter so as to maintain the output voltage at a set value. The excitation current supplied from 17 to the field winding 13 for the main exciter is controlled.

[0005] The rotor 3 of the main generator 2 is formed by winding a main field winding 4 around a coil winding portion of a salient pole iron core made of a laminated iron plate fitted to a rotating shaft. Both ends of the winding 4 are rectifier circuits 11 in which rectifiers 11a to 11d are connected in a single-phase full-wave connection.
Is connected to the DC output terminal of

The stator 5 of the main generator includes an annular stator core disposed so as to surround the rotor 3 from the outside, and a main armature winding wound around a slot provided in the stator core. The output terminals of the main armature winding 6 are output terminals 16a and 16b of the brushless synchronous generator 1.

The armature 10 for the main exciter is wound around a salient pole core fitted on the same rotating shaft as the rotor 3 of the main generator, and both ends of the winding of the armature 10 are rectifier circuits. 11 AC input terminals.

The stator 12 of the main exciter is formed by winding a field winding 13 for the main exciter around a salient pole core having an annular yoke disposed so as to surround the rotor 9 from the outside. 13 are connected to an automatic voltage regulator 18 at both ends.
Although the main exciter 8 is a single-phase generator in this example, it may be constituted by a three-phase generator. In this case, the rectifier circuit 11 connected to the output side of the main exciter 8 is a three-phase full-wave It may be a circuit.

The sub-exciter 15 is a magnet generator comprising a magnet rotor 16 fixed to the same rotating shaft as the rotor 9 of the main exciter, and a generating coil 17 for generating a voltage by the rotation of the magnet rotor. The output end of the power generation coil 17 is connected to the automatic voltage regulator 18. The structure and the number of poles of the magnet generator constituting the sub-exciter 15 are arbitrary.

When the brushless synchronous generator 1 having the above structure is driven and rotated by the prime mover, an AC output corresponding to the rotation speed is generated in the power generation coil 17 of the sub-exciter 15.
This output is rectified by a rectifier (not shown) included in the automatic voltage regulator 18 and supplied to the main exciter field winding 13 of the main exciter 8. As a result, an exciting current flows through the field winding 13 for the main exciter, and an output obtained by amplifying the output of the sub-exciter 15 is obtained in the armature 10 for the main exciter of the main exciter 8. This output is supplied to the main field winding 3 of the main generator 2 via the rectifier circuit 11, and the exciting current is supplied to the main field winding 3. As a result, an output voltage is quickly established on the main armature winding 6.

The automatic voltage regulator 18 used together with the brushless synchronous generator 1 has a voltage regulator circuit (not shown) composed of a transistor or the like. From 15, the exciting current supplied to the main exciter field winding 13 of the main exciter 8 is controlled, and the output voltage of the main generator 2 is automatically adjusted to the rated value.

In the above example, the main generator 2 has a single-phase configuration, but the main generator may be a three-phase generator depending on the application.

As described above, when a magnet generator is used as a sub-exciter, the sub-exciter is not affected by the output voltage of the main generator. As a result, good output characteristics can be obtained even for an inductive load having a large starting current.

Further, the sub-exciter (magnet generator) can supply a sufficient exciting current to the main exciter from a low speed range, so that it is not only possible to easily establish the voltage of the main generator, but also to have a wide rotation speed range. Good output characteristics can be obtained.

Further, with the above configuration, the output of the main generator can be adjusted by controlling the exciting current of the main exciter, so that a small-capacity voltage adjusting device can be used.

[0016]

Although a synchronous generator is originally used at a synchronous speed (rated speed), when supplying power to a load where the frequency does not matter, for example, a fish catching lamp (incandescent lamp) is used. For example, when power is supplied to a lamp, the generator may be used to increase the rotation speed of the generator to obtain an output larger than the rated output. Therefore, when such usage is anticipated, it is necessary to design to withstand a certain degree of overload.

However, since the magnet generator has a characteristic that the output increases with an increase in the rotation speed, when the magnet generator is used as the sub-exciter 15 to excite the main exciter 8, the rotation speed is reduced. If the output increased excessively with the rise of the power and the operation was continued with the rotational speed higher than the rated value, the temperature of the generator would rise excessively and the generator might be damaged. . Hereinafter, this point will be described in more detail.

FIG. 4 shows an example of the output characteristics of the magnet generator (the characteristics of the output voltage Et 'with respect to the output current IL') using the rotation speeds N1, N2 and N3 [rpm] (N1 <N2 <N3) as parameters. Become like Here, N1 is the rated rotation speed (synchronous rotation speed) of the generator.

In FIG. 4, Rf represents a resistance line having a gradient of the resistance value of the field winding 13 of the main exciter 8, and the magnet generator constituting the sub-exciter 15 has an output characteristic at each rotation speed. It operates at the intersection of the curve and the resistance line Rf.
That is, when the rotation speed is N1, the magnet generator
And the output current (excitation current of the main exciter) is i
f1, the output voltage becomes V1. When the rotational speed is N2, the motor operates at the point a2 and the output current and the output voltage become if2 and V2, respectively. When the rotational speed is N3, the motor operates at the point a3 and the output current and the output voltage become if3 and V3, respectively.
Becomes Therefore, when the rotation speed increases from N1 to N3,
The exciting current of the main exciter increases from if1 to if3.

Looking at the relationship between the output voltage Et of the main armature winding 6 (output voltage of the generator) Et and the load current IL, as shown in FIG. 5, the rated speed N1 (excitation current of the main exciter) = I
The characteristic at the time of f1) becomes like c1 -d1 -e1, and the characteristic at the rotational speed N3 becomes like c3 -d3 -e3. That is, at the rated rotation speed N1, the rated load current IL1 flows at the rated voltage E1, but when the rotation speed increases to N3, the output voltage greatly increases.

In order to keep the output voltage of the generator at the rated voltage E1 when the rotational speed increases, the automatic voltage regulator 18
However, the automatic voltage regulator of the synchronous generator used conventionally supplies the exciting current to the main exciter field winding 13 when the output voltage is equal to or lower than the set value, and When the output voltage exceeds the set value, the field winding 1 for the main exciter
The excitation current of the field winding for the main exciter is controlled in accordance with the output voltage so as to stop the supply of the excitation current to the motor 3.

FIG. 6 shows output voltage Et vs. load current IL characteristics when such an automatic voltage regulator 18 is used in a brushless synchronous generator using a magnet generator as a sub-exciter. That is, the output characteristics when the rotational speed is N1 are as shown by the curves f1 -g1 -h1 in FIG. 5, while the characteristics when the rotational speed is N3 are as shown by the curves f1 -g3 -h3. As is clear from FIG. 6, when the rotation speed is increased to N3, the load current can flow to IL3 while maintaining the rated voltage E1. Because it is designed to maintain the temperature,
When the load current increases to IL3, heat generation becomes too large, causing an excessive rise in temperature.

When the rotation speed is N1, the control range of the exciting current in the automatic voltage regulator 18 is ifo to if1,
The control range of the exciting current when the rotational speed is N3 is ifo 'to i
When f3 is reached and the number of revolutions increases, the control range of the exciting current is greatly widened.

As described above, for a brushless synchronous generator using a magnet generator as a sub-exciter, a general automatic generator having a function of simply controlling the excitation current of the main exciter according to the output voltage. When a voltage regulator is used, the output that can be taken out increases significantly when the engine is operated at a rotational speed higher than the rated value, so excessive overload operation is performed and the temperature of the generator increases. Could rise excessively. If the operation is continued while the temperature of the generator is excessively increased, the varnish of the winding of the rotor is softened, so that the winding may expand due to centrifugal force and an accident such as contact with the stator may occur. .

In order to withstand the overload of the generator, the conductor cross-sectional area of the winding is increased, the capacity of the core is increased to increase the heat capacity of the generator, and the insulation class of the winding is increased. However, in this case, there is a problem that the size of the generator is increased and the cost is significantly increased.

When the conventional automatic voltage regulator is used, there is a problem that the control range of the exciting current becomes very wide as the number of revolutions increases, so that an unstable control region is easily generated. .

An object of the present invention is to provide a brushless system capable of suppressing an excessive increase in output when the engine is operated at a rotational speed exceeding the rated rotational speed and reducing the control range of the exciting current to perform stable control. An object of the present invention is to provide an automatic voltage regulator for a synchronous generator.

[0028]

SUMMARY OF THE INVENTION The present invention provides a main generator comprising a rotor having a main field winding and a stator having a main armature winding, and supplying an exciting current to the main field winding. A main exciter having a rotor having a main exciter armature and a stator having a main exciter field winding, and a magnet generator for supplying an exciting current to the main exciter field winding. The present invention relates to an automatic voltage regulator of a brushless synchronous generator provided with a sub-exciter and a rotating shaft in common.

In the present invention, a constant voltage control circuit which outputs a DC voltage equal to the set value V1 with the output voltage of the sub-exciter as an input, and the output voltage Et of the main armature winding is set to the rated value E
When the output voltage of the main armature winding exceeds the rated value E1, the excitation current is supplied to the field winding for the main exciter with the output voltage of the constant voltage control circuit when the output voltage is less than or equal to 1. An exciting current control circuit for the main exciter for controlling the exciting current of the exciting winding for the main exciter so as to stop the supply of the exciting current to the field winding. The set value V1 of the constant voltage control circuit is set to a value necessary for generating the rated output E1 in the main armature winding at the rated speed.

[0030]

When the constant voltage control circuit is provided as described above, the apparent output characteristic of the sub-exciter at the rated rotation speed N1 (output characteristic of the constant voltage control circuit) is represented by the curve j-
a1 -b1 and the output characteristic when the rotational speed is N3 is as shown by a curve j-a3 '-b3. Considering the load straight line Rf of the field winding of the main exciter, the rated speed N
The operating point at 1 is point a1 and the operating point at N3 is also point a1. That is, the voltage applied to the field winding of the main exciter becomes V1 and the exciting current becomes if1 (constant) both at the rated rotation speed N1 and when the rotation speed increases to N3. Therefore, the output characteristics of the generator when the rotation speed is N3 are as shown by the curve c3'-d3'-e1 in FIG. 5, and the increase in the output when the rotation speed increases from the rated value N1 to N3. Is suppressed.

The control width of the exciting current in the automatic voltage regulator when the rotational speed is increased to N3 is equal to ifo in FIG.
'If1, which is much narrower than conventional ifo' to if3. Therefore, stable control can always be performed.

[0032]

FIG. 1 shows the overall configuration of an embodiment of the present invention. In this embodiment, a main exciter 8 is composed of a three-phase AC generator, and an armature 10 of the main exciter 10 is used. The phase output is input to a three-phase full-wave rectifier circuit 11 including diodes 11a to 11f. A varistor 20 is provided at the output terminal of the rectifier circuit 11.
And the output voltage of the rectifier circuit is applied to the main field winding 4 formed by connecting a plurality of coils in a single-phase connection. A load 21 is connected between output terminals 16a and 16b derived from the main armature winding 16. FIG. 7 shows another configuration of the generator.
Is the same as that shown in FIG.

The automatic voltage regulator 18 according to the present invention comprises:
With the output of the sub-exciter 15 as an input, the set value V is set at least at a speed equal to or higher than the rated speed, regardless of the speed.
Constant voltage control circuit 18a that outputs a DC voltage equal to 1
When the output voltage Et of the main armature winding 6 is equal to or less than the rated value E1, an exciting current if is supplied to the main exciter field winding 13 with a DC voltage obtained from the constant voltage control circuit 18a. When the output voltage Et of the slave winding 6 exceeds the rated value E1, the excitation current of the excitation winding 13 for the main exciter is stopped so that the supply of the excitation current if to the field winding 13 for the main exciter is stopped. And an excitation current control circuit 18b for the main exciter to be controlled. Here, the set value V1 of the constant voltage control circuit is set to a value necessary for generating the rated output E1 on the main armature winding 6 at the rated speed N1.

FIG. 2 shows a specific configuration example of the constant voltage control circuit 18a and the exciting current control circuit 18b for the main exciter.
In the constant current control circuit 18a shown in FIG. 2, a control rectifier circuit is constituted by diodes D1 and D2 and thyristors Th1 and Th2, and a sub-exciter 15 is connected between terminals M and M connected to input terminals of the control rectifier circuit. (Magnet generator) output voltage is applied. Phototransistor P for controlling the supply of trigger signals to thyristors Th1 and Th2
A photocoupler comprising Tr and a photodiode PD1 is provided, and the phototransistor PTr is provided so as to bypass the trigger signals of the thyristors Th1 and Th2 from the thyristor when conducting.

When the sub-exciter 15 generates an AC output, a trigger signal is supplied to the thyristors Th1 and Th2 through the diode D3 or D4, the resistors R1 and R2, and the diodes D5 and D6. Therefore, thyristors Th1 and T1
h2 conducts each time a forward voltage is applied between the respective anode and cathode, and the output terminals m1 and m1 of the control rectifier circuit and
DC voltage is output during m2. This DC voltage is applied to both ends of the capacitor C1 through the choke coil L1.

The DC voltage Vt obtained at both ends of the capacitor C1 is detected by a voltage dividing circuit comprising resistors R3 and R4 and a variable resistor VR1. When the DC voltage obtained at both ends of the capacitor C1 is equal to or less than the set value V1, the voltage across the resistor R3 does not exceed the Zener voltage of the Zener diode Z1, so that no base current is supplied to the transistor Tr1, and the transistor Tr1 is turned off. Is kept. At this time, since the light emitting diode PD1 does not emit light, the phototransistor PTr does not conduct and the thyristors Th1 and Th2
The trigger signal is supplied without any trouble. Therefore, in this state, the output voltage Vt of the magnet generator is rectified by the control rectifier circuit and supplied to the main exciter exciting current control circuit 18a.

When the voltage Vt across the capacitor C1 exceeds the set value V1, the Zener diode Z1 is turned on, so that a base current is applied to the transistor Tr1 and the transistor is turned on, causing the light emitting diode PD1 to emit light. As a result, the phototransistor PTr becomes conductive, and the supply of the trigger signal to the thyristors Th1 and Th2 is prevented. As a result, the charging of the capacitor C1 is stopped, and the voltage Vt across the capacitor C1 is maintained at the set value V1. The set value V1 can be appropriately adjusted by the variable resistor VR1.

The exciting current control circuit 18b for the main exciter has a transformer Tsf for detecting the output voltage Et of the generator, and the output of the transformer is connected to the resistors R11 and R12 through a rectifier circuit composed of diodes D11 to D14. Variable resistor VR2
Are applied to both ends of the voltage dividing circuit. When the output voltage Et of the generator is equal to or lower than the rated value E1, the voltage across the resistor R11 of the voltage dividing circuit does not exceed the Zener voltage of the Zener diode Z2, so that the transistor Tr2 is in a cut-off state. At this time, the FET1 is in the conductive state, and one end of the capacitor C1 of the constant voltage control circuit 18b → the terminal J → the exciting winding 13 for the main exciter → the terminal F → the FET1 → the other end of the capacitor C2. An exciting current if flows through the magnetic winding 13.

The output voltage Et of the main armature winding is equal to the rated value E1.
Is exceeded, the Zener diode Z2 conducts.
When a base current is applied to the transistor Tr2, the transistor is turned on and the FET1 is turned off. As a result, the supply of the exciting current to the main exciter field winding 13 is stopped, so that the output of the main exciter 8 is reduced, the exciting current of the main field winding 4 is reduced, and the output of the generator is reduced. The voltage Et decreases. When the output voltage Et becomes equal to or lower than the rated value E1, the transistor Tr2 is turned off again, the FET1 is turned on, and excitation commutation is supplied to the field winding 13 for the main exciter. By repeating these operations, the output voltage E of the generator
t is kept at the rated value E1. The rated value E1 can be appropriately adjusted by the variable resistor VR2.

FIG. 3 shows another example of the configuration of the constant voltage control circuit 18a.
It was shown to. In this example, terminals M and M connected between the output terminals of the magnet generator are connected to the input terminal of a full-wave rectifier circuit composed of diodes D21 to D24, and a capacitor C1 is connected between the DC output terminals of the rectifier circuit. I have. The voltage across the capacitor C1 is applied to the exciting current control circuit 18a for the main exciter through Darlington connected transistors Tr3 and Tr4. A zener diode Z3 is connected between the base of the transistor Tr4 and the negative terminal of the capacitor C1, and a voltage across the capacitor C1 is applied to both ends of the zener diode Z3 through a resistor R20. The exciting current control circuit 18b for the main exciter is shown in FIG.
Has the same configuration as the example shown in FIG.

In the constant current control circuit 18a shown in FIG.
The Zener diode Z3 is set so as not to conduct when the rectified output of the magnet generator obtained at both ends of the capacitor C1 is equal to or less than the set value V1. Therefore, when the output voltage of the magnet generator is equal to or lower than the set value V1, the transistors Tr3 and Tr4 are turned on to apply the DC voltage Vt to the exciting current control circuit 18b for the main exciter. When the rectified output of the magnet generator obtained at both ends of the capacitor C1 exceeds the set value V1, the Zener diode Z3 conducts, so that the transistors Tr3 and Tr4 are cut off, and the DC current to the main exciter exciting current control circuit 18b is reduced. The output of the voltage Vt is stopped. The rectified output of the magnet generator obtained at both ends of the capacitor C1 is equal to the set value V
When it becomes equal to 1, the transistors Tr3 and Tr4 become conductive again, and apply a DC voltage equal to the set value to the exciting current control circuit 18b for the main exciter. By repeating these operations, the voltage applied to the field winding 13 for the main exciter becomes the set value V1.
Is kept.

When the constant voltage control circuit 18a is provided as in each of the above embodiments, the apparent output characteristics (output characteristics of the constant voltage control circuit) of the sub-exciter at the rated speed N1 are as shown in FIG. The output characteristic when the rotational speed is N3 is as shown by a curve j-a3 '-b3.
Therefore, if the load straight line of the field winding 13 of the main exciter 8 is Rf, the operating point at the rated rotation speed N1 is a1.
The operating point when the rotational speed is N3 is also the point a1. Therefore, the voltage applied to the field winding of the main exciter can be set to V1 and the exciting current can be set to if1 (constant) both at the rated rotation speed N1 and when the rotation speed increases to N3. The output characteristic of the generator when the rotation speed is N3 is represented by a curve c3 in FIG.
'-D3'-e1, and the increase in output when the rotational speed increases from the rated value N1 to N3 is suppressed.

The control width of the exciting current in the automatic voltage regulator when the rotation speed increases to N3 is equal to ifo in FIG.
'If1, which is much narrower than the control widths ifo' to if3 in the conventional automatic voltage regulator. Therefore, stable control can always be performed.

[0044]

As described above, according to the present invention, the constant voltage control circuit for outputting the DC voltage of the set value V1 with the output of the sub-exciter (magnet generator) as an input, and the main armature winding When the output voltage Et is equal to or lower than the rated value E1, an exciting current is supplied to the field winding for the main exciter with the output voltage of the constant voltage control circuit, and the output voltage Et of the main armature winding exceeds the rated value E1. A main excitation motor excitation current control circuit that controls the excitation current of the main excitation motor excitation winding so as to stop the supply of the excitation current to the main excitation motor field winding when the constant voltage control is performed. Since the set value V1 of the circuit is set to the value required to generate the rated output on the main armature winding at the rated speed, the exciting current of the main exciter must be constant regardless of the speed. Can be
It is possible to suppress an increase in output when the operation is performed in a state where the rotation speed is higher than the rated value. Therefore, when the operation is performed in a state where the rotation speed is high, the temperature of the generator can be prevented from excessively rising, and the generator can be prevented from being damaged.

According to the present invention, since the control range of the exciting current of the main exciter can be narrowed, stable control can always be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a specific configuration example of the automatic voltage regulator of FIG. 1;

FIG. 3 is a circuit diagram showing another specific configuration example of the automatic voltage regulator of FIG. 1;

FIG. 4 is a diagram showing output characteristics of a magnet generator used in an embodiment of the present invention.

FIG. 5 is a diagram showing a comparison between the output characteristics of a generator provided with a constant current control circuit and the output characteristics of a generator not provided with a constant current circuit as in the present invention.

FIG. 6 is a diagram showing output characteristics and excitation current versus load current characteristics when an automatic voltage regulator is provided for an embodiment of the present invention and a conventional example.

FIG. 7 is a configuration diagram showing a configuration of a brushless synchronous generator targeted by the present invention.

[Description of Signs] 1 ... brushless synchronous generator, 2 ... main generator, 3 ... rotor, 4 ... main field winding, 5 ... stator, 6 ... main armature winding,
8 main exciter, 9 rotor, 10 armature for main exciter,
11: rectifier circuit, 12: stator, 13: field winding for main exciter, 15: sub-exciter, 16: magnet rotor, 17: power generation coil.

Claims (1)

(57) [Claims] 1. A main generator comprising a rotor having a main field winding and a stator having a main armature winding, and an armature for a main exciter for supplying an exciting current to the main field winding. A main exciter including a rotor having a main exciter and a stator having a main exciter field winding, and a sub-exciter including a magnet generator for supplying an exciting current to the main exciter field winding are rotated. An automatic voltage regulator for a brushless synchronous generator provided with a common axis, wherein a constant voltage control circuit that outputs a DC voltage equal to a set value V1 with an output voltage of the sub-exciter as an input; When the output voltage Et of the line is equal to or less than the rated value E1, an exciting current is supplied to the field winding for the main exciter with the output voltage of the constant voltage control circuit, and the output voltage Et of the main armature winding is rated. When the value exceeds the value E1, the supply of the exciting current to the field winding for the main exciter is stopped. An exciting current control circuit for the main exciter for controlling the exciting current of the exciting winding for the main exciter, so that the set value V1 of the constant voltage control circuit is the rated armature winding at the rated speed. An automatic voltage regulator for a brushless synchronous generator, wherein the voltage is set to a value required to generate a rated output on a wire.