JPS6273595A - Inverter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field] Is this invention free? l! - This invention relates to a single-stone inverter device for lighting a pump at high frequency.

[Background technology]

FIG. 1O shows a circuit diagram of a conventional 1' inverter device. In FIG. 10, ■ is a DC power supply, 2 is a switching transistor, 64 is a transformer, 5 is a capacitor, and the I-order winding N+ of the transformer 4 and the capacitor 5 form a series resonant circuit.

3 is an inductor for discharging the capacitor 5.

6 is a load supplied with power from the secondary winding N2 of the transformer 4. 7 is a capacitor, 8 and 9 are resistors, which constitute the base drive circuit 1 of the switching 1-transistor 2,
A rectangular wave voltage from a base drive signal generation circuit (not shown) is input to a terminal 50.

10 is a diode (flywheel diode) connected in antiparallel to the switching transistor 2.

Figure 1) is a waveform diagram of each part of the circuit in Figure 10, and (A
) is the base drive of switching transistor 2'! ! (B) shows the collector 1! of the switching transistor 2. ! (C) shows the collector voltage 1"EV (:E) of the switching transistor 2. Hereinafter, the operation of the circuit shown in FIG. 10 will be explained with reference to FIG. 1). This inverter device has switching transistor 2
The collector current (c) that flows when the is on becomes a resonant type and supplies a high surface tll current to the load 6.

In FIG. 10, a rectangular wave voltage is supplied to a terminal 50 by a base drive signal generator. Terminal 5 at time 18-2
When the input voltage to 0, that is, the rectangular wave voltage becomes high level, the switching transistor 2 receives a voltage from the differential type base drive circuit that is initially high and gradually decreases to a value determined by the resistor 8.9. The base drive current I
B flows. At this time, the primary winding N1 of the transformer 4 constituting the series resonant circuit. The current flowing through the capacitor 5 and the inductor 3 flows through the switching transistor 2 as a collector current 1c, and this collector current IC becomes a resonant type.

Time 1. The collector 14 flow IC reaches its peak at , and then decreases. Then, at time t2, when the rectangular wave voltage becomes a low level and the collector current IC becomes zero, the diode 1
0 is turned on, current ID flows, collector voltage VCE rises at time t3, switching transistor 2 is turned on again at time t4, and in return, energy is supplied to load 6.

However, since the base drive current supplied to the switching transistor 2 [B is the first line] has a waveform as shown in Figure (A), the base drive current IB is less than the required base current value near the peak of the collector current 1c. 1) Figure (C
), the saturation voltage of the collector voltage VCE increases, causing an inconvenience that the loss of the switching transistor 2 increases.

To solve such problems, it is necessary to increase the capacitance of the capacitor 7, decrease the resistance value of the resistor 8, or increase the peak value of the rectangular wave voltage applied to the terminal 50. As a result, the entire base drive current IB increases, resulting in an increase in ta loss in the base drive circuit (2).

FIG. 12 shows a circuit diagram of another conventional inverter device R. This inverter device was proposed in order to solve the problem of the circuit shown in FIG. In Fig. 12, 1 is a DC power supply, 2 is a switching transistor, 3 is an inductor, 4 is a transformer, 5 is a condenser/capacitor, 6 is a load, 7 is a capacitor, 8 and 9 are resistors, and 10 is a diode. The parts are the same as Figure 10.

51 are windings N, , N2 . In a current transformer with N3, the winding N
2 is inserted and connected between the capacitor 5 and the switching transistor 2, and the winding N3 is connected to the base drive circuit (7, 8, 9
) I, a switching transistor 52 is connected in series to the winding N1, a rectangular wave voltage is applied to the base of the switching transistor 52 from a terminal 57 through a resistor 53,54, and a DC type voltage is applied to the winding N1 of the transformer 51. -a1
A DC voltage is applied via a capacitor 55 and a resistor 56.

FIG. 13 is a waveform diagram of each part in FIG. 12, where (A) shows the base drive of the switching transistor 2 1) i5klB
(B) is the collector 1)i of the switching transistor 2
The current 1c and the current ID of the diode 10 are shown, and (C) shows the collector voltage VCE of the switching transistor 2, respectively.

The operation of the circuit shown in FIG. 12 will be explained below with reference to FIG. 13. In this inverter device, like the one in FIG. 10, the collector current IC that flows when the switching transistor 2 is on becomes a resonant type and supplies a high frequency current to the load 6.

The operation of the circuit shown in FIG. 12 will be explained in detail below.

This inverter device converts the collector current IC flowing into the winding N2 of the current transformer 51 from the winding N3 to the base drive circuit! 81, its current transformation ratio is N2/N3, and it has a current supply capacity of 'IIi flow supply is no longer necessary.

Therefore, the base drive current IB is approximately proportional to the collector current 1c, the saturation voltage of the collector voltage VCE does not increase, and the loss of the switching transistor 2 does not increase.

Note that the switching transistor 52 is turned on and off in the opposite manner to the switching transistor 2, and when the switching transistor 52 is turned off, the switching transistor 52 is turned on and off from the winding N1 to the winding N1.
The switching transistor 2 is turned on by the pulsed rebound voltage applied to the switching transistor 3 .

However, in such a circuit configuration, a current transformer 51 for the base drive is required, which increases the cost and increases the size. Further, when the diode 10 is turned on and the current In is flowing, a reverse current is shunted to the current transformer 51, and the switching transistor 2 is turned on by the rebound voltage of the current transformer 51, and the collector current flL
There is a problem in that Ic flows as shown at point B in FIG. 13(B), causing abnormal oscillation and resulting in unstable operation.

[Purpose of the invention]

It is an object of the present invention to reduce the loss of the switching transistor by fully driving the switching transistor, reduce the loss of the switching transistor drive circuit, and further reduce the size, cost, and speed of operation by eliminating the need for a drive transformer. An object of the present invention is to provide an inverter device that can achieve stability.

[Disclosure of the invention]

The inverter device of the present invention utilizes the base-emitter charge N product of a switching transistor provided between a DC power source and a load, and generates a plurality of necessary base drive currents without using a base drive transformer. It is characterized by supplying a pulsed current having peaks of .

That is, in the inverter device of the present invention, a switching transistor is provided between a DC power source and a load, and a base driving WhM current is periodically supplied to the switching transistor to turn the switching transistor on and off to supply power to the load. The inverter device is characterized in that the base drive N current is constituted by a pulsed current having a plurality of peaks.

FIG. 14 shows a waveform diagram for explaining the principle of this invention.
FIG. 14(A) shows the collector current 1c flowing through the switching transistor, and this collector current Tc
To flow through the switching transistor, ideally, a base drive current +9 as shown in FIG. 14(B), which is approximately the reciprocal of the DC current amplification factor hFE at that current value, is required.

In this invention, this current is supplied by the pulsed current In' (solid line) having multiple peaks as shown in FIG. 14(C) and the accumulated charge between the base and emitter of the switching transistor. . In FIG. 14(C), in the section where the pulsed current +B+ is lower than the required base drive current IB (break 1jl), the base drive current I R7'+ < flows due to the discharge of the stacked charges between the base and emitter. become. In other words, the base drive current IB required for the switching transistor is supplied by simply generating the next peak before the switching transistor shifts to the off state due to the decrease in the M stacked load due to one peak of ′ from the pulsed current. It is possible to supply the drive current to the base intermittently.

According to the structure of the present invention, since the base drive current given to the switching transistor is composed of a pulsed current having multiple peaks, the peak value of the base drive current can be set to a high value and the switching transistor can be sufficiently driven. can reduce the loss of switching transistors.Also,
Pulse 1! Since this is a current, the loss of the switching transistor drive circuit can also be reduced. Furthermore, since a drive transformer is not required, it is possible to achieve downsizing, cost reduction, and stable operation.

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 and 2. As shown in FIG. 1, this inverter device includes a switching transistor 2 provided between a DC power supply 1 and a load 6, and turns the switching transistor 2 on and off by periodically supplying a base drive current to the switching transistor 2. The inverter device is characterized in that the base drive signal is composed of a pulsed current having a plurality of peaks.

In this case, the next peak of the pulsed current is generated before the base drive current due to the accumulated charges between the base and emitter of the switching transistor 2 becomes smaller than the required base current value.

This will be explained in more detail below. This inverter device is
As shown in FIG. 1, a series resonant circuit consisting of the primary winding N1 of a transformer 4 and a capacitor 5 is connected to a DC 'ti source 1 via a switching transistor 2, and a series resonant circuit consisting of a primary winding N1 of a transformer 4 and a capacitor 5 is connected to the DC'ti source 1. An inductor 3 is connected in parallel, a load 6 is connected to a secondary winding N2 of a transformer 4, and a diode 10 is connected in antiparallel to the switching transistor 2.

Further, a base drive circuit I consisting of a capacitor 7 and a resistor 8.9 is connected to the base of the switching transistor 2, and a rectangular wave voltage is applied from a terminal 50.

The configuration up to this point is the same as that in FIG. 1O.

In this embodiment, a capacitor 1), a resistor 12, a diode 13 . Buffer 14. Resistance 15° Buffer 16
．． Capacitor 17. An auxiliary base drive circuit (2) consisting of a diode 18 is provided.

FIG. 2 is a waveform diagram of each part in FIG. Indicates the voltage VB, (D> is the switching transistor 2
(E) shows the collector current 1c of the switching transistor 2 and the current ID of the diode 10, and (F) shows the collector voltage VCE of the switching transistor 2.

The operation of the circuit shown in FIG. 1 will be explained below with reference to FIG. When the voltage ■8 applied to the terminal 50 at time to becomes high and becomes low, the first peak occurs in the base drive current IB due to the action of the base drive circuit I, the switching transistor 2 is turned on, and the current remains unchanged until time L1. The base-emitter M charge accumulated by this pulsed current keeps it on, and the collector current 1c flows in a sinusoidal manner.

On the other hand, the output of the buffer 14 is at the time to
becomes a high level and charges the capacitor 17 through the resistor 15 of the time constant circuit. As a result, the voltage VI7 of the capacitor 17 rises, and when this voltage V17 exceeds the threshold voltage VTR of the buffer 16, the output voltage VB of the buffer -F16 becomes high level. In other words, voltage vT3 becomes high level at time t1, which is delayed by the time determined by the time constant of the time constant circuit, from voltage VA, and this one time 1. A second peak will occur in the heath drive current I[l. Note that this delay time is set so that the next peak occurs before the base current flowing to the switching transistor 2 disappears due to the accumulated charge in the switching transistor 2.

As a result, even at time t2 when the collector current IC of the switching transistor 2 reaches its peak value, the base drive is 1!
There is no shortage of current, and the minimum necessary pulsed current suppresses the rise in the saturation voltage of the collector voltage VCE, reducing the loss of the switching transistor 2.

After this, the switching transistor 2 continues to be turned on due to the charge accumulated between the base and emitter due to the pulsed current of the second peak, and at time t3, the diode IO is turned on, current IQ flows, and at time t4, the collector voltage VC
E increases, the switching transistor 2 is turned on again at time t5, and high frequency power is supplied to the load 6 by repeating this process.

Therefore, it is not necessary to make the peak value of the pulsed current higher than necessary or to use a base drive transformer, and the loss of the base drive circuit I can be reduced, and it is also possible to reduce the size, cost, and stabilize operation. can be achieved.

A second embodiment of the invention will be described based on FIG.

This inverter device has a terminal 50 as shown in FIG.
and the base drive circuit I between transistors 2), 22.
27, 30. Resistance 23゜24.25, 28.29.31
．． A control circuit (2) consisting of a capacitor 26° and a DC power source 32 is provided, and the other features are the same as those shown in FIG.

In this inverter device, the transistor 22 is turned on when the voltage 6 is at a high level, so the switching transistor 2 is turned off.

When the voltage 6 becomes low level, the transistor 22 is turned off and the voltage of the DC power supply 32 is applied to the base drive circuit I through the resistor 31, and the first peak of the base drive current IB is supplied to the switching transistor). be done. At this time, the voltage of the capacitor 7 increases only to a voltage determined by the ratio of the resistors 8 and 31. On the other hand, transistor 2
) is turned off at the same time as the voltage I becomes low level, and as a result, the capacitor 26 is charged through the resistor 25, its voltage rises, and after a certain time delay from the time when the voltage I6 becomes low level, the capacitor 26 is charged through the resistor 25. 27 is turned on, and therefore the transistor 30 is turned on.As a result, the resistor 31 is short-circuited, and the voltage of the DC type #32 is directly applied to the base drive circuit I, and at this time, the second of the base drive current !B The peak will be supplied to the switching transistor 2.

The rest is the same as the first embodiment.

The effects of this embodiment are similar to those of the first embodiment.

A third embodiment of the invention will be described based on FIG. 4.

This inverter device is an example in which a base drive current consisting of a pulsed current having four peaks is created, and as shown in FIG. 4, capacitors 7a to 7d and resistors 8a to
A pulsed current having four peaks is applied to the base of the switching transistor 2 by sequentially applying a rectangular wave voltage with a delayed phase to the terminals a w d of the base drive circuit ■ consisting of 8d, diodes 13b to 13d, and resistor 9. It is something. The number of peaks can be increased to 4+I1 or more by further arranging circuits consisting of capacitors, resistors, and diodes in parallel.

Note that the same voltage as the voltage applied to the terminal 50 in FIG. 1 is applied to the terminal a, and the same voltage as the output of the buffer 16 in FIG. 1 is applied to the terminals b-d.

The configuration other than the above is the same as in FIG. 1.

This makes it possible to accommodate base current waveforms of various shapes.

A fourth embodiment of this invention will be described based on FIG.

This inverter device includes a capacitor 7, resistors 8, 9, . Resistor 28a
~28d,) transistors 30a~30d, resistors 31a~
This circuit uses a base drive circuit (2) consisting of 31d, and by sequentially applying a rectangular wave voltage with a delayed phase to the terminals a' to d', a pulsed current with a fixed peak is applied to the switching transistor 2. The effect is the fourth
It is similar to the one shown in the figure.

A fifth embodiment of this invention will be described based on FIG. 6.

As shown in FIG. 6, this inverter device replaces the series resonant circuit of the primary winding N+ of the transformer 4 and the capacitor 5 in FIG. and inductor 3
The circuit is the same as that shown in FIG. 3, and the collector voltage of this circuit is resonant when the switching transistor 2 is off.

FIG. 7(A) shows the base drive titIB of the switch notching transistor 2 in the fifth embodiment.
) shows the collector current 1c of the switching transistor 2 and 14'tLIo of the diode 10;
) is the collector voltage VCE of switching transistor 2
It shows.

In this inverter circuit, when the switching transistor 2 is on, the collector current Ic is 1 of the transformer 4.
The current increases linearly through the next winding N1, but the seventh
Pulse-like 1ti with multiple peaks as shown in Figure (A)
j! ! By supplying this to the switching transistor 2 as a base drive current, there is no need to increase the peak value of the pulsed current more than necessary or use a base drive transformer.

A sixth embodiment of this invention will be described based on FIG.

This inverter device includes the capacitor 7 in FIG.
Base drive circuit consisting of resistor 8.9! In place of, resistor 8
．． Inductor 33. This circuit uses a base drive circuit (■') consisting of a parallel circuit of diodes 34. In this case as well, a pulsed current having multiple peaks is applied from terminals 35 and 36 to the switching transistor 2 as a base drive current. An effect similar to that in Figure 1 can be achieved.

A seventh embodiment (1) 1 of the present invention will be explained based on FIG. 9. As shown in FIG. 9, this inverter device detects an increase in the saturation voltage of the collector voltage VCE of the switching transistor 2 and supplies the second peak of the pulsed current to the switching transistor 2.

More specifically, when the rectangular wave voltage applied to the terminal 46 is at a high level, the switching transistor 2 is off.

When the rectangular wave voltage becomes low level, the transistor 22
is turned off, and the first peak of the pulsed current flows through the capacitor 7 and the resistor 8°9 to the switching transistor 2.
The switching transistor 2 is turned on.

Furthermore, when the rectangular wave voltage is at a low level, that is, when the output of the inverting buffer 44 is at a high level, the collector voltage VCE of the switching transistor 2 is
When the voltage divided by 1.42 exceeds the threshold voltage of the AND circuit 45, the transistor 27 turns on.
Transistor 30 is turned on and the second peak is supplied to switching transistor 2 in a manner similar to the circuit of FIG. 43 is a Zener diode.

Other configurations and effects are similar to the circuit shown in FIG.

〔Effect of the invention〕

According to the inverter device of the present invention, since the base drive current given to the switching transistor is composed of a pulsed current having a plurality of peaks, the switching transistor can be sufficiently driven without increasing the peak value of the base drive current. Loss in switching transistors can be reduced. Furthermore, since the current is pulsed, loss in the driving circuit of the switching transistor can also be reduced. Furthermore, since a drive transformer is not required, it is smaller and lower in cost.

Operation stability can be achieved.

[Brief explanation of drawings]

FIG. 1 is a diagram of the first embodiment of this invention, FIG. 2 is a waveform diagram of each part, FIG. 3 is a circuit diagram of the second embodiment of this invention, and FIG. 4 is a diagram of this embodiment. A circuit diagram of a third embodiment of the invention,
Fig. 5 is a circuit diagram of a fourth embodiment of the present invention, Fig. 6 is a main circuit diagram of a fifth embodiment of this invention, Fig. 7 is a waveform diagram of each part thereof, and Fig. 8 is a circuit diagram of the fifth embodiment of the invention. A circuit diagram of a sixth embodiment of
Fig. 9 is a circuit diagram of the seventh embodiment of the present invention, Fig. 10 is a circuit diagram of a conventional inverter device, Fig. 1) is a waveform diagram of each part thereof, and Fig. 9J7412 is a circuit diagram of another conventional inverter device. FIG. 13 is a waveform diagram of each part thereof, and FIG. 14 is a waveform diagram for explaining the principle of this invention. 1...DC*S, 2...Switching transistor, 6...Load, ■...Base drive circuit, ■...Auxiliary base drive circuit 1--Direct power supply 2--Also 4) '7-Trun''; Screw 6・-Load ■・-α'-Scanning circuit n--One-way pivoting opening to the rarest rib (Figure 3, Figure 4, Figure 6, I Figure 10, Figure 1) Figure ■ Figure 12 Figure 13 (A) le to) Is' Figure 14

Claims (4)

[Claims] (1) An inverter device in which a switching transistor is provided between a DC power source and a load, and by periodically supplying a base drive current to the switching transistor, the switching transistor is turned on and off to supply power to the load. An inverter device according to the present invention, wherein the base drive current is a pulsed current having a plurality of peaks. (2) Claim (1) wherein the next peak is generated in the pulsed current before the base current due to the charge accumulated between the base and emitter of the switching transistor becomes smaller than a necessary base current value. The inverter device described. (3) The inverter device according to claim (1), wherein a rise in saturation voltage when the switching transistor is turned on is detected to generate the next peak in the pulsed current. (4) The inverter device according to claim (1), (2) or (3), wherein the current flowing through the switching transistor is of a resonant type.