JPS6031440Y2 - Automatic voltage regulator for excited alternator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an automatic voltage regulator for an excitation type alternator.

An example of a conventionally used automatic voltage regulator is shown in FIG.

In the figure, 1 and 2 are the armature winding and field winding of the excitation type AC generator, respectively, 3 is the excitation winding provided in the generator, and the excitation winding 3 is the induced voltage of the armature winding 1. Generates an output voltage that is 90 degrees out of phase with the voltage.

The output voltage of the excitation winding 3 is determined by the thyristor S, S2 and the diode D2. It is applied to both ends of the field winding 2 through a mixed bridge type controlled rectifier circuit connected to D3.

A reverse voltage absorbing diode D1 is connected between both ends of the field winding 2.

The anodes of thyristors S□ and S2 are diode D5-
Connected to the anode of D4 and to the diode.

The cathodes of D4 are connected to each other and connected to resistors R5 and R.
4 to the anode of diode D6.

The cathode of diode D6 is connected to the gate of thyristor S□ via resistor R1 and to the gate of thyristor S2 via resistor R2.

Of the above, diode D5. D4, resistor R6, R2,
Diode D6 and resistors R□, R2 connect thyristor S1. A circuit is configured to give an ignition signal to the gate from the anode side of S2.

The cathode of diode D6 is also connected via resistor R3 to thyristor S1. Connected to the cathode of S2.

There is a Zener diode Z0 at the connection point of resistors R5 and R2.
The cathode of Zener diode B is connected to the anode of thyristor S1. Connected to the cathode of S2.

The collector of the transistor Tr□ is connected to the anode of the diode D6, and the emitter of the transistor Tr1 is connected to the cathode of the thyristor S and S2.

The transistor Tr1 is connected as described above, and constitutes a transistor switch circuit that bypasses a phase control firing signal to the thyristors S□ and S2 when it becomes conductive.

On the other hand, a load 4 is connected to the output end of the armature winding 1, and the voltage across this load is transmitted via an output voltage detection transformer 5 to diodes D, D8. D9. D.

Input to full wave rectifier 6 from: full wave rectifier 6
A smoothing capacitor C□ and resistors R1o, R
9 and R8 are connected in parallel, and the detection voltage v1 obtained across the resistor R8 is applied between the base and emitter of the transistor Tr via the Zener diode and the resistor R7.

Further, a resistor R6 is connected between the base and emitter of the transistor Tr□.

And code 5? 6? C1? Rso, Rot
Rst R7? A detection and comparison circuit 7 is constructed by members indicated by Re and O, which detects the output voltage of the generator and provides a signal to make the transistor switch circuit conductive when the output voltage exceeds a set value.

Figures 3A-C and 4A-C show the waveforms of each part of the device in Figure 1. Figures 3A-C are for light loads, and Figures 4A-C are for heavy loads. This is the waveform under load.

When the detection voltage v1 exceeds the Zener voltage e2 of the Zener diode z2, the Zener diode Z2 becomes conductive, a base current flows through the transistor Tr□, and this transistor becomes conductive.

When the transistor Tr1 becomes conductive, its internal resistance decreases, so that almost all of the current flowing from the excitation winding 3 through the diode D and the resistors R5 and R4 flows through the transistor Tr, and the current flows through the thyristor S1. No firing signal is provided to S2.

When the detection voltage v1 becomes smaller than the Zener voltage e2, the base current of the transistor Tr□ decreases and its internal resistance increases.

As a result, the voltage v2' between the collector and emitter of the transistor Tr1 increases, and the voltage v2' between the collector and emitter of the transistor Tr1 increases. The level required to trigger S2 is reached, which causes thyristor S
1 or S2 becomes conductive, and a voltage 3 as shown in FIG. 3B or FIG. 4B is applied to the field winding 2.

When the output voltage of the generator is large, the conduction period of the transistor Tr1 becomes long and the thyristor S1. When the firing angle of S2 becomes large and, conversely, the output voltage of the generator is small, the conduction period of transistor Tr1 becomes short, and the thyristor S
1. The firing angle of S2 becomes smaller.

In this way, the output voltage of the generator is adjusted to be substantially constant.

The Zener diode 4 eliminates ripples in the output voltage of the excitation winding 3 and stabilizes the voltage applied between the collector and emitter of the transistor Tr□ through the resistor R4, thereby suppressing fluctuations in the firing angle of the thyristors S□ and S2. This was established to prevent this.

In the conventional voltage regulator described above, when the generator becomes heavily loaded or rotates at high speed, the phase difference between the induced voltage in the armature winding 1 of the generator and the terminal voltage increases.
The phase of the terminal voltage of the armature winding lags behind the terminal voltage of the excitation winding, and the waveform distortion becomes large (see the waveform shown by the broken line in FIG. 4A).

Therefore, the phase of detection voltage v1 lags behind the voltage between the anode and cathode of thyristors S□ and S2, and
．． At the time when the voltage between the anode and cathode of S2 rises, the transistor Tr1 is cut off, and an undesirable voltage (incorrect pulse) appears between the collector and emitter of the transistor Tr1.

If this voltage (illegal pulse) is large enough to exceed the trigger level L/et of the thyristor, the thyristor S
1. S2 is ignited and becomes almost full-width conductive, which causes the terminal voltage of the generator to pulsate, and when a lamp is connected as a load, the lamp flickers.

The present invention aims to prevent the above-mentioned irregular pulses from occurring, reduce the pulsation of the terminal voltage, and suppress undesirable phenomena such as flickering of the lamp.

Examples of the present invention will be described below.

FIG. 2 shows an embodiment of the present invention.

The apparatus shown in FIG. 1 is substantially similar to the apparatus shown in FIG. 1, but differs in the following points.

That is, thyristor S1. A negative feedback branch by capacitor C2 is provided in the transistor switch circuit provided between the gate and cathode of S2.

More specifically, one terminal of the capacitor C2 is connected to the collector of the transistor Tr1, and the other terminal is connected to the anode of the Zener diode z2.

When capacitor C2 is connected in this way, transistor T
An integral operation is performed by r5, capacitor C2, resistor R7, etc., and the collector-emitter voltage 2 of transistor Tr1 becomes a sawtooth wave as shown in the third and fourth diagrams, thereby preventing the generation of illegal pulses.

This point will be discussed in detail below.

Assume now that the Zener diode 4 has remained conductive for a sufficiently long time and the capacitor C2 has been charged to the polarity shown.

Next, when the detection voltage v1 decreases and becomes lower than the Zener level e2, the capacitor C2 is connected to the resistor R7, R6, the field coil 2, the diode D2, the exciting coil 3, the diode D4, and the resistor Rst R4. Discharge.

At this time, a part of the discharge current of the capacitor C2 is supplied to the base of the transistor Tr1, so the transistor Tr1
does not cut off immediately, but gradually transitions from a conductive state to a cut-off state.

Therefore, even if a voltage is applied from the excitation winding 3, the voltage v2 between the collector and emitter of the transistor Tr1 does not rise immediately but gradually rises.

During this time, capacitor C2 completes its discharge and is then charged to a polarity opposite to that shown.

The voltage v2 between the collector and emitter of the transistor Tr1 is the voltage v2 between the collector and emitter of the transistor Tr1. When the trigger level et of S2 is reached, thyristor S2. S2 is fired.

The transistor Tr is turned on by the conduction of the thyristors S□ and S2.
1's collector-emitter voltage v2 drops rapidly.

Along with this, the potential of the anode of the Zener diode 4 decreases, and the Zener diode Z2 becomes conductive. line, diode D7 or D8, resistor R1o
, R9 and the Zener diode 4, it is discharged and then charged again to the polarity shown.

At this time, the base current of the transistor Tr1 is connected to the resistor R7.
However, the greater the resistance value of resistor R7, the greater the voltage drop, and the higher the charging voltage of capacitor C2.

The slope of the rising portion of the sawtooth wave can be made gentler by increasing the resistance value of the resistor R7, and by doing so, it is possible to sufficiently absorb false pulses.

As described above, according to the present invention, a negative feedback branch using a capacitor is installed in the transistor switch circuit provided between the gate and cathode of the phase control thyristor to perform an integral operation, thereby preventing the generation of illegal pulses. , the thyristor can be controlled stably by sawtooth waves,
Pulsations in the terminal voltage of the generator can be prevented.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a conventional example of a voltage regulator for an excitation type AC generator, Fig. 2 is a circuit diagram of an embodiment of the present invention, and Figs. FIG. 3 is a waveform diagram of each part of the embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Armature winding, 2... Field winding, 3... Excitation winding, Sl, S2... Thyristor, Trl... Transistor, 7... Detection comparison circuit, C2. ...Negative feedback capacitor.

Claims (1)

[Scope of utility model registration request] a thyristor provided between an excitation winding and a field winding of the generator for controlling the phase of the excitation current of the excitation type alternating current generator; a transistor switch circuit provided between the gate cathode of the thyristor; automatic voltage excitation type alternator, comprising: a detection comparison circuit that detects the output voltage of the generator and provides a signal for making the transistor switch circuit conductive when the output voltage exceeds a set value; An automatic voltage regulator for an excited alternator, wherein the transistor switch circuit has a negative feedback branch including a capacitor.