JPS5828827B2 - transistor inverter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transistor inverter device.

Figure 1 shows a universal transistor inverter, where OT is a transformer, with input winding N1, output winding N2 and feedback winding N
It has 3.

Z is the load, Trl is the switching transistor, R
1 is a bias resistor, and C1 is a capacitor for setting the oscillation cycle.

Now, when a medium voltage is applied from the power supply Vcc, charging of the capacitor C1 starts with the polarity shown in the figure through the resistor R1, and the capacitor C1 is charged with a time constant determined by the resistor R1 and the capacitor C1. Go and its charging voltage■
When c1 becomes equal to or higher than the B-E on voltage of transistor Tr1, base current IB flows through this transistor Tr1.

This base current IB causes a collector current Ic times hFE to flow through the input winding N1 in the transistor Tr1.

At this time, the input winding N1 and the feedback winding N3 are wound on the same core, and when the collector current Ic flows through the input winding N1, a voltage is applied to the feedback winding N3 in the direction shown in FIG. This voltage tends to further turn on the transistor Tr1, resulting in positive feedback, and the transistor Tr1 quickly reaches saturation.

At this time, capacitor C1 is charged in the direction shown in FIG.

When the transistor Tr1 reaches saturation, the collector current I
c stops increasing, and the induced voltage on the feedback winding N3 becomes O
Since the base current IB becomes O, the transistor Tr1 is turned off.

On the other hand, since the capacitor C1 is charged in the aforementioned direction, the same operation is repeated after this voltage Vc1 is discharged from Vcc.

In this way, a sine wave is generated in the input winding N1 by turning on and off the collector current Ic accompanying the switching operation of the transistor Tr1, and power is supplied to the load Z. At this time, the oscillation frequency is: The factor determined by the natural frequency of the input winding N1 and the like is much stronger than the setting by the capacitor C1.

If the above is summarized in terms of waveforms, it will be as shown in Figure 3.

Here, power is supplied to the load Z by the transistor Tr.
Not only during the ON period of 1, but also during the OFF period, the power during the half cycle is shared and supplied to the load Z by the energy stored in the inductance of the transformer OT during the ON period.

The output control of the transistor inverter is performed using the transistor T.
This is possible by controlling the on-period of r1, and the control of the on-period is intended to reduce the collector current Ic supplied as the load power or the stored power to the transformer inductance.

In other words, the shaded area shown in FIG. 4 is to be eliminated.

However, reducing the collector current Ic during the ΔTon period in Fig. 4 can be considered to increase the oscillation frequency, but as mentioned above, the oscillation frequency is determined by the natural frequency of the transformer OT including the load Z. Since the collector current Ic is strong, no matter how long the collector current Ic is energized, its repetition period, that is, the frequency f, does not change at all as shown in FIG. 4, and only the power (input/output) changes.

In other words, it attempts to change the duty cycle of oscillation.

By setting this ΔTon by the necessary amount at the necessary time, it is possible to control the power as desired.

In this case, the collector current Ic of the transistor Tr1 is
Since the necessary base current IB is flowing during this energization, if the base current IB is cut off at the time of Ton-△Ton in Fig. 4, it is possible to turn off the collector current Ic earlier than the normal on period. Therefore, it is sufficient to turn on the switch and ground the base of the transistor Tr.

However, the actual collector current Ic and base current IB have a relationship as shown in Figure 5, and in the latter half of the collector current Ic conduction period, the base current IB is extremely small, so it is difficult to simply turn on the switch. Simply shorting the base and emitter of transistor Tr1 will reduce the collector current I.
c does not turn off.

This is because in this type of inverter, its collector current I
This is because the base current IB required for c is supplied by carriers accumulated in the transistor TrI.

In view of these conventional problems, the present invention provides a transistor inverter device that reliably guides the collector current Ic to turn-off and enables power control of the inverter output. A reverse bias circuit includes a fourth winding provided in the transformer and a switching element, and reverse biases the transistor by a voltage generated in the fourth winding when the switching element is turned on; A trigger pulse generation circuit supplies a trigger pulse to the switching element so as to trigger the switching element to turn it on during an on period, and a synchronization circuit controls the trigger pulse generation circuit in synchronization with the oscillation cycle of the inverter. The second feature is that the transformer includes a fourth winding and a switching element, and when the switching element is turned on, the voltage generated in the fourth winding activates the transistor. a reverse bias circuit that applies a reverse bias; a trigger pulse generation circuit that supplies a trigger pulse to the switching element so as to trigger the switching element to turn it on during the on period of the transistor; The third feature is that it includes a synchronization circuit that controls the pulse generation circuit, and a power response circuit that controls the pulse generation period of the pulse generation circuit in response to fluctuations in the power supply voltage. a reverse bias circuit that has a fourth winding provided in a transformer and a switching element, and reverse biases the transistor by a voltage generated in the fourth winding when the switching element is on; and during the on period of the transistor. A trigger pulse generation circuit supplies a trigger pulse to the switching element so as to trigger the switching element to turn on the switching element, and a synchronization circuit controls the trigger pulse generation circuit in synchronization with the oscillation cycle of the inverter. The fourth feature is that the generation circuit is provided with a CR delay circuit for setting the pulse generation period, and a power supply response circuit is provided that changes the resistance value of the CR delay circuit in response to fluctuations in the power supply voltage. , a reverse bias circuit having a fourth winding provided in a transformer and a switching element, and reverse biasing the transistor by a voltage generated in the fourth winding when the switching element is turned on; and an on-period of the transistor. a trigger pulse generation circuit that supplies a trigger pulse to the switching element so as to trigger the switching element to turn it on; a synchronous circuit that controls the trigger pulse generation circuit in synchronization with the oscillation cycle of the inverter; The fifth feature is that the transformer includes a fourth winding provided in the transformer and a switching element,
and a reverse bias circuit that reverse biases the transistor using a voltage generated by a fourth winding when the switching element is turned on, and a trigger pulse applied to the switching element so as to trigger and turn on the switching element during the on period of the transistor. The trigger pulse generation circuit is equipped with a trigger pulse generation circuit that supplies pulse generation, and a synchronization circuit that controls the trigger pulse generation circuit in synchronization with the oscillation cycle of the inverter.The trigger pulse generation circuit is equipped with a CR delay circuit for setting the pulse generation cycle, and the feedback from the load is The present invention is characterized in that a feedback circuit is provided which varies the resistance value of the CR delay circuit depending on the signal received.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. In the present invention, as a means for surely guiding the collector current Ic to turn-off, it is constructed as shown in FIG.

That is, the transformer OT of the transistor inverter 1 is provided with a fourth winding N4 continuous to the feedback winding N3, and
Transistor T r2 as a switching element,
Tr3 is connected to Darlington, and these constitute a reverse bias circuit 2, and the voltage generated in the fourth winding N4 is applied between the base and emitter of the transistor Tr1 when transistors Tr2 and Tr3 are turned on, and is reverse biased. By flowing current, the transistor Tr is turned off and the collector current Ic is turned off.

The timing at this time is Ton-△To in Figure 4 mentioned above.
It must be set at a time of n, and this △Ton has no meaning unless it is varied within Ton. Therefore, a trigger pulse generation circuit from the monostable multi-bi break 3 is added, and the trigger pulse generates the reverse. Controls the timing of the bias circuit 2.

There is no need to describe the monostable multi-bibreak 3 any further, but it operates as follows.

In a normal stable state, a base current flows from Vcc through the resistor R2 to the transistor Tr4, and the transistor Tr4 is in an on state.

At this time, its collector voltage is O, and the transistor T
Since the base voltage of r5 is O, it is in an off state.

Now, when a negative potential trigger is applied to the trigger point a of the transistor Tr4, the transistor Tr4 is turned off and the collector voltage rises, so the transistor Tr5 is turned on this time, shifting to the unstable side.

After this, since the base of the transistor Tr4 is connected to Vcc through the resistor R2, the base potential of the transistor Tr4 rises in a time determined by the resistor R2 and capacitor C2 of the CR delay circuit 4, and the base potential of the transistor Tr4 increases.
4 is turned on and the state is the same as the beginning.

That is, when viewed in terms of the collector voltage of the transistor Tr5, it becomes as shown in FIG. 7, and by adopting the following configuration as the synchronous circuit 5, synchronization with the oscillation frequency of the inverter 1 can be easily achieved.

In addition, transistor Tr2 for switching element. Tr3
It is best to use the voltage at which the transistor Tr is turned off again for the timing of the resistor R2 of the CR delay circuit 4.
By varying the value of the capacitor C2, the time can also be varied.

At the time of triggering the monostable multi-by-break 3, the base of the transistor Tr4 needs to have a potential even lower than the one potential of Vcc, so there is no need to add a special circuit for that, and the primary and secondary insulation of the transformer OT is protected. If so, it is necessary to detect it from the primary side circuit.

For this purpose, for example, the voltage of the input winding N1, the capacitor C1, etc. may be used, but in this example, the charging voltage c1 of the capacitor C1 is used.

The phase of the capacitor voltage c1 with respect to the collector voltage is as shown in Figure 8, and the required negative voltage is the collector current I
It is after the rise of c.

Since the voltage for reducing the collector current Ic uses the collector voltage of the transistor Tr5, it is convenient if the transistor Tr5 turns on when the capacitor voltage c1 rises, that is, when the collector current Ic rises, as shown in Fig. 8. In reality, as shown in FIG. 9, the turn-on of the transistor Tr5 is delayed a little with respect to the capacitor voltage Vc1, and this reduces the collector current of the transistor Tr1, which may cause an abnormality in the collector current Ic waveform or abnormal oscillation. turn into.

Therefore, it is necessary to turn on the transistor Tr5 before the rise of the collector current Ic and lead the monostable multi-bi break 3 to the non-stable side. To do this, the monostable multi-bi break 3 must be guided to the non-stable side by using the ten potential side of the capacitor voltage V C1. I have to get a ten trigger to vibrator 3.

Therefore, as shown in FIG. 6, a transistor Tr6 that operates at the +potential of the capacitor voltage c1 is provided, and one voltage of the monostable multivibrator 3 is applied in advance to the actual V
The synchronous circuit 5 is configured by setting the voltage to be higher than ccH, and the trigger point of the transistor Tr4 (
By connecting the base) to Vccm, triggering by the capacitor voltage Vc, (-t-) is possible.

As a result, as shown in Figure 10, the monostable multi-bi break 3
The transition to the unstable side, that is, the turning on of the transistor Tr5 occurs before the rising point of the collector current Ic, and there is no effect on the collector current Ic.

Next, the collector voltage of the transistor Tr5 is used to trigger the reverse bias circuit 2, but if this collector voltage is used directly, the impedance of the monostable multi-bi break 3 is high and it is difficult to obtain the desired bias. The transistors T r2 and T r3 are connected in Darlington as described above to increase hFE and ensure reliable operation.

With the above configuration, the collector current Ic of the transistor Tr1 can be reduced and the output control of the inverter 1 can be achieved, but if the on period of the transistor Trs of the monostable multivibrator 3 is controlled, the power can be made constant.

In this case, the on period is determined by the time constant of the resistor R2 and capacitor C2 of the CR delay circuit 4, as described above.
All you have to do is change the degree of inclination, but electrically the resistance R2
is easy to change.

Furthermore, it is appropriate to use the power supply voltage shown in FIG. 6 and the load output fluctuation shown in FIG. 11 as detection factors.

FIG. 6 uses a power response circuit 6 that responds to fluctuations in power supply voltage, and the power response circuit 6 is a transistor Tr.
7. It is composed of a resistor R3 and a Zener diode ZD.

Therefore, according to this configuration, when the Zener diode ZD is set to the required voltage, the apparent resistance R2 is
It exhibits characteristics as shown in FIG. 12, and the transistor Tr,
Since the on-period of T is 0.7RC, as shown in FIG. 18, when <Vcc increases, T, that is, the on-period of the transistor Tr1 becomes shorter, and a constant power can be achieved.

FIG. 11 uses a feedback circuit 7 for feeding back the load output, and this feedback circuit 7 is composed of a transistor Tr, a resistor R4, a transformer T, a rectifier circuit S, and the like.

In the case of FIG. 6, since it is configured to respond to the power supply voltage, the trigger point to the synchronous circuit 5 is set to the capacitor voltage V.
If c1 is constant and this trigger voltage is constant, when the power supply voltage fluctuates, the trigger point moves between Δ as shown in FIG. 14 due to changes in capacitor voltage vc1, thereby exhibiting constant power property.

However, the change in Δt due to the fluctuation width of the power supply is extremely small, and a satisfactory reduction rate of the collector current Ic cannot be expected.

Therefore, as shown in FIG. 6 or FIG. 11, a CR delay circuit 4 is interposed in the trigger pulse generation circuit, and this CR delay circuit 4
The cycle is controlled by the output from the power supply response circuit 6 or the feedback circuit 7 over the entire required collector current Ic reduction range, and by doing so, even better constant power performance can be obtained.

The trigger pulse generation circuit, that is, the synchronization circuit 5 for the monostable multivibrator 3, uses the capacitor voltage ■c1 for the on-voltage of the transistor Tr6 set by the transistor Tr6 and the resistor R5 to generate the transistor Tr6.
Since the on-voltage of this transistor Tr6 is always constant, the trigger point does not change at all with respect to the capacitor voltage c1 as shown in FIG.

Moreover, the control was to change the period T of the non-stable side of the monostable multi-bi flake 3.

On the other hand, even when T is always constant and the trigger point of the monostable multi-bi break 3 is moved, the inverter 1
output control is possible.

Figure 16 shows a variable resistor VR at the base of the transistor Tr6.
, and the transistor T due to the capacitor voltage ■c1
This changes the on-phase of r6.

Figures 17 and 18 use a photocoupler FC, and Figure 17 responds to fluctuations in power supply voltage, while Figure 18 uses transformer T2, rectifier circuit 82, etc. to feedback load fluctuations. According to these, not only output control but also constant power can be achieved.

In other words, the phase of the synchronization circuit 5 is adjusted, and the purpose can also be achieved by this phase adjustment.

The delay period of CR delay circuit 4 is determined by resistor R2 and capacitor C2.
The charging cycle of the capacitor C2 changes if the power supply voltage changes with the resistor R2 constant.

Therefore, the charging characteristic of the capacitor C2 shows a change as shown by the dotted line in FIG. 19, but this change cannot control the period of the CR delay circuit 4 to the extent that it can cover the required reduction range of the collector current Ic.

Therefore, if nonlinear elements such as the transistor Tr7 and the Zener diode ZD are connected to the resistor R2 of the CR delay circuit 4 as shown in FIG.
The change is shown as the solid line shown in FIG. 9, and the change in delay time due to power supply fluctuation becomes large, and good characteristics are obtained as a constant power.

That is, a non-linear element is added to the resistor R2 of the CR delay circuit 4. According to this, the change in delay time with respect to fluctuations in the power supply becomes large, and very good constant power performance can be obtained.

In addition, as shown in FIG. 11, if a transistor Tr8 is connected to the resistor R2 of the CR delay circuit 4 and it is controlled by a signal fed back from the load Z, the load fluctuation due to the power supply voltage, and the load when the power supply voltage is constant. It can respond sufficiently to fluctuations in the current, and the constant power effect becomes even better.

As described in detail in each of the embodiments above, according to the first invention, the transformer has a fourth winding, and when the transistor is turned on, the transistor is reverse biased by the voltage generated in the fourth winding. A reverse bias circuit is provided, and this is controlled in synchronization with the inverter via a pulse generation circuit and a synchronization circuit to reduce the output current, so the output of the inverter can be arbitrarily controlled.

be able to. According to the second invention, since the power supply response circuit is provided to control the pulse generation period of the trigger pulse generation circuit in response to fluctuations in the power supply voltage, in addition to the power control according to the first invention, the power supply voltage fluctuates. Even in such cases, fluctuations in output power can be prevented and output power can be made constant.

According to the third invention, the trigger pulse generation circuit includes a CR delay circuit for setting the pulse generation cycle, and the power response circuit
Since the resistance value of the delay circuit is changed, the change in the delay time of the CR delay circuit with respect to fluctuations in the power supply voltage becomes large, and very good constant power performance can be obtained.

According to the fourth aspect of the invention, since a circuit for controlling the phase of the synchronous circuit is provided, it is possible to achieve constant power even by this phase control.

According to the fifth invention, since the feedback circuit is provided to vary the resistance value of the CR delay circuit according to the signal fed back from the load, it is possible to handle not only load fluctuations due to power supply voltage but also load fluctuations when the power supply voltage is constant. It is possible to respond sufficiently to the current, and the effect of constant power property becomes even better.

[Brief explanation of drawings]

Figures 1 and 2 are circuit diagrams for explaining the principle, Figures 3 to 5
The figure is a waveform diagram, and FIG. 6 is a circuit diagram showing an embodiment of the present invention.
7 to 10, 12 to 15, and 19 are characteristic diagrams, and FIG. 11, 16 to 18 are circuit diagrams showing other embodiments. 1...Transistor inverter, OT...
...Transformer, N4...4th winding, 2...
・Reverse bias circuit, 3... Monostable multivibrator, 4... CR delay circuit, 5...
Synchronous circuit, 6...Power response circuit, 7...
・Feedback circuit.

Claims (1)

[Claims] 1. A transformer comprising a switching transistor, an input winding, an output winding, and a feedback winding for positive feedback,
A self-commutated transistor inverter in which the base of the transistor is connected to a connection point between a bias resistor and an oscillation period setting capacitor via the feedback line, and includes a fourth winding provided in the transformer and a switching element. and a reverse bias circuit that reverse biases the transistor by a voltage generated by a fourth winding when the switching element is turned on; A transistor inverter device comprising: a trigger pulse generation circuit that supplies an l-IJ pulse to an element; and a synchronization circuit that controls the trigger pulse generation circuit in synchronization with an oscillation cycle of an inverter. 2. Equipped with a transistor for switching, a transformer having an input winding, an output winding, and a feedback winding for positive feedback,
In a self-commutated transistor inverter in which the base of the transistor is connected to a connection point between a bias resistor and an oscillation period setting capacitor via the feedback winding, a fourth winding provided on the transformer and a switching element are connected. and a reverse bias circuit that reverse biases the transistor by a voltage generated by a fourth winding when the switching element is on, and a reverse bias circuit that triggers the switching element to turn on the switching element during the on period of the transistor. a trigger pulse generation circuit that supplies a trigger pulse to the
It is characterized by comprising a synchronization circuit that controls the trigger pulse generation circuit in synchronization with the oscillation cycle of the inverter, and a power response circuit that controls the pulse generation cycle of the trigger pulse generation circuit in response to fluctuations in the power supply voltage. Transistor inverter device. 3 comprising a transistor for switching, a transformer having an input winding, an output winding and a feedback winding for positive feedback,
In a self-commutated transistor inverter in which the base of the transistor is connected to a connection point between a bias resistor and an oscillation period setting capacitor via the feedback winding, a fourth winding provided in the transformer and a switching element are connected. and a reverse bias circuit that reverse biases the transistor by a voltage generated by a fourth winding when the switching element is turned on; a trigger pulse generation circuit that supplies a trigger pulse to the element;
The trigger pulse generation circuit is equipped with a synchronization circuit that controls the pulse generation circuit in synchronization with the oscillation cycle of the inverter, and the trigger pulse generation circuit is provided with a CR delay circuit for setting the pulse generation cycle, and the CR delay circuit responds to fluctuations in the power supply voltage. A transistor inverter device comprising a power supply response circuit that varies the resistance value of the transistor. 4. The transistor inverter device according to claim 3, wherein the power response circuit includes a nonlinear element, and the nonlinear element is connected in parallel to the resistor of the CR delay circuit. 5 comprising a transistor for switching, a transformer having an input winding, an output winding, and a feedback winding for positive feedback,
In a self-commutated transistor inverter in which the base of the transistor is connected to a connection point between a bias resistor and an oscillation period setting capacitor via the feedback winding, a fourth winding provided on the transformer and a switching element are connected. and a reverse bias circuit that reverse biases the transistor by a voltage generated by a fourth winding when the switching element is on, and a reverse bias circuit that triggers the switching element to turn on the switching element during the on period of the transistor. a trigger pulse generation circuit that supplies a trigger pulse to the
A transistor inverter device comprising: a synchronous circuit that controls a trigger pulse generation circuit in synchronization with the oscillation cycle of the inverter; and a circuit that controls the phase of the synchronous circuit. 6. Equipped with a switching transistor, a transformer having an input winding, an output winding, and a feedback winding for positive feedback,
In a self-commutated transistor inverter in which the base of the transistor is connected to a connection point between a bias resistor and an oscillation period setting capacitor via the feedback winding, a fourth winding provided on the transformer and a switching element are connected. and a reverse bias circuit that reverse biases the transistor by a voltage generated by a fourth winding when the switching element is on, and a reverse bias circuit that triggers the switching element to turn on the switching element during the on period of the transistor. a trigger pulse generation circuit that supplies a trigger pulse to the
It is equipped with a synchronization circuit that controls the trigger pulse generation circuit in synchronization with the oscillation cycle of the inverter, and a CR delay circuit for setting the pulse generation cycle is provided in the trigger pulse generation circuit, and the resistance of the CR delay circuit is determined by the signal fed back from the load. A transistor inverter device characterized by being provided with a feedback circuit that varies a value.