JPH03212165A - Inverter unit - Google Patents

Abstract

PURPOSE:To enable high speed switching of a switching element by providing a current supply means for shortening the time to be elapsed before the potential, at the joint to a voltage detecting element, reaches to such level as turning the other switching element OFF when one switching element is turned OFF. CONSTITUTION:Upon turn OFF of a switching element SW2, current is sustained by the energy stored in a load circuit 5 and an auxiliary resonance circuit and charges the capacitance component Cs of the switching element SW2. Consequently, outputs Vc1, Vc3 from drive circuits 41, 43 are inverted instantaneously and since an auxiliary resonance circuit 6 for turning the switching elements SW1, SW2 ON are provided, the switching element SW1 is turned ON immediately upon turn OFF of the switching element SW2.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an inverter device in which alternating current can be supplied to a load from between a pair of switching elements connected in series by alternately turning on and off the switching elements.

[Conventional technology]

In this type of inverter device, as shown in FIG. 18, a diode D as a voltage detection element is inserted between a pair of switching elements SW, SW2, and the output of the oscillation circuit 2 is connected to the switching element SW2. The switching element is controlled to be turned on and off by the output of the drive circuit 4□ that receives it, and both switching elements SW+ and SW2 are alternately turned on and off based on the potential at the connection point of the series circuit of the switching element SW2 and the diode D1. A configuration has been considered in which the SW1 is controlled on and off by the output of the drive circuit 41. That is, a series circuit in which a diode D is inserted in the forward direction between switching elements sw, sw2 is connected between both terminals of a power supply E, and both switching elements S are connected by a control circuit 1.
WI and SW2 are controlled to turn on and off. The control circuit 1 turns on and off an oscillation circuit 2 for timing setting and a switching element SW according to the output ■ of the oscillation circuit 2.
Drive circuit 4□ for off-control and switching element S
A drive circuit 41 for controlling W1 on and off,
Oscillation circuit 2 and drive circuit 4. ．． 42 are power supplies Ea, E4. Equipped with E2. A series circuit of a resistor R1 and a diode D is connected between both ends of the power source E1,
The connection point between resistor R6 and diode D1 is the drive circuit 4.
Connected to the input terminal of 1. Further, the load circuit 5 is connected between both ends of the series circuit of the switching element SW2 and the diode D1. The load circuit 5 includes a series circuit of an inductance L and a capacitor Ca connected across a series circuit of a switching element SW2 and a diode D, and a DC cut capacitor cb and a capacitor Ca connected between both ends of the capacitor Ca. A series circuit with a load l is connected. According to this configuration, the oscillation circuit 2 obtains the output ■ as shown in FIG. 19(a), and when the output V of the oscillation circuit 2 rises at time t0, the 1]! 1(b), the output VC2 of the drive circuit 42 rises and the switching element SW2 is turned on. When the switching element SW2 is turned on, the drive circuit 41 is turned on as shown in FIG. 19(d).
The potential at the input end of the drive circuit 4 becomes low, and the output Vc+ of the drive circuit 4 falls as shown in FIG. 19(e).
The switching element SW is turned off. At this time, as shown in FIG. 19(c), the potential ■ at the connection point between the switching element S W + and the load circuit 5. becomes 0. Furthermore, since the current tends to continue to flow due to the energy stored in the load circuit 5, after the current I0 flows through the diode D as shown in FIG. 19(i), the switching element as shown in FIG. 19(g) A current Ist flows through SW2. On the other hand, as shown in FIG. 19(a), at time 1. oscillation circuit 2
When the output ■ falls, the output V of the drive circuit 42
c2 falls and switching element SW2 turns off. As a result, diode DI is turned off and the first
As shown in Fig. 9 (d), the input V1 of the drive circuit 4 rises. Therefore, the switching element S W + is turned on. 19<n will flow. By repeating the above operation, a sinusoidal current lff1 as shown in FIG. 19(h) will flow through the load l. In short, , switching element SW is turned on and off depending on switching element SW2, thereby preventing both switching elements SW, , SW2 from being turned on at the same time, and switching elements SW l, S
This prevents the switching elements sw, , sw2 from being destroyed due to the short circuit current flowing through W2.

[Problem to be solved by the invention]

In the above configuration, the switching elements SW, SW are generally composed of transistors or thyristors, so
As shown in FIG. 18, when the switching element SW2 is turned off at time 0, when it is considered that a capacitance component Cs exists between both terminals when the switching element SWx is turned off, Due to the stored energy in the load circuit 5, the potential vO at the connection point between the switching element SW1 and the load circuit 5 increases as shown in FIG. 19(c), and a charging current flows into the capacitance component Cs via the diode D. , diode D1 is turned off at time t11, drive circuit 4. The output Vc rises and the switching element S W + turns on. here,
l1l so that the load circuit 5 can store a sufficiently large amount of energy during the ON period of the switching element SWl.
The time (t x t +) will be short if the load circuit 5 has a small amount of energy stored in the load circuit 5, but the time (t-1+) will be long if the stored energy of the load circuit 5 is small. Furthermore, if the load circuit 5 is resistive and has no stored energy, the capacitive component Cs is charged by the power source E1 via the resistor R7, so the time (1++ 1 +) becomes longer. In this way, when time%n(t++ t+) becomes longer,
While switching element SW2 is off, switching element S
There is a delay before turning on W+, and switching element S
A problem arises in that WI and SW2 cannot be turned on and off at high speed. That is, the output frequency of the oscillation circuit 2 is limited. The present invention aims to solve the above-mentioned problems and provides an inverter device that can turn on and off switching elements at high speed.

[Means to solve the problem]

In order to achieve the above object, the present invention connects a series circuit of a pair of switching elements and a voltage detection element inserted between both switching elements between both ends of a DC power supply,
One switching element is controlled on and off by a control circuit, and both switching elements are alternately turned on and off based on the potential at the connection point of the series circuit between the one switching element and the voltage detection element. In an inverter device that controls on/off of the other switching element and supplies alternating current to the load from the connection point between the other switching element and the voltage detection element, one of the switching elements turns off. Sometimes, current supply means is provided to shorten the time until the potential at the connection point with the voltage detection element reaches a potential that can turn off the other switching element.

[Effect]

According to the above configuration, since the capacitance component generated when one of the switching elements controlled on/off by the control circuit is turned off is charged by the current supply means, the switching element and the voltage detection element are charged. The time it takes for the potential at the connection point to reach a potential that can turn off the other switching element is shortened, and the time from turning off one switching element to turning on the other switching element is shortened, resulting in faster switching operation. It will be transformed into

Embodiment 1 In this embodiment, as shown in FIG. 1, an auxiliary resonant circuit 6 is provided within the control circuit 1. The auxiliary resonant circuit 6 has a diode D' connected in parallel to a series circuit of an inductance L' and a capacitor C', and a switching element SWz is connected in series to the auxiliary resonant circuit 6. The anode of diode D' is connected to the negative terminal of power supply E. The switching element SW3, like the switching element SWl, is controlled on and off via the drive circuit 43 so as to be subordinate to the switching element SW2. That is, switching element SW is connected in series to switching element SW2 via diode D connected in the forward direction, and switching element SW2. sw, , diode Dj
A series circuit of is connected across the power supply E. Further, a series circuit of a diode D and a resistor R1 is connected across the power source E3 with the anode of the diode D3 connected to the negative electrode of the power source E. Drive circuit 4. The input terminal of is a diode D and a resistor R.
It is connected to the cathode of diode D, which is the connection point with 1. The other configurations are the same as the conventional example shown in FIG. 1O. Next, the operation will be explained. The output V of the oscillation circuit 2 is shown in Fig. 2 (
As shown in a), this is an output in which high and low voltages are alternately obtained at a constant period. When the output V of the oscillation circuit 2 rises at time t0, the output V c 2 of the drive circuit 42 also rises, turning on the switching element SW2, as shown in FIG. 2(b). When the switching element SW2 is turned on, Fig. 2(d)
As shown, when the input voltage V to the drive circuit 41.43 is 0
Therefore, as shown in FIGS. 2(e) and 2(f), the drive circuit 4. , i's outputs Vc, , Vc fall, and the switching elements sw, , sw are turned off at the same time. When both switching elements sw, , sw are turned off, the load circuit 5
And the energy stored in the auxiliary 5OjJ path 6 causes the current to continue to flow, so the second [
As shown in g(k)(1), current flows through the diodes r) and D'. Thereafter, as shown in FIG. 2(j), a current Is2 flows through the switching element SW2. On the other hand, when the output V of the oscillation circuit 2 is inverted at time t1, the switching element SW2 is turned off. At this time,
The capacitive component Cs of the switching element SW2 is charged by a current supplied from the load circuit 5 shown in FIG. 2(h) through the diode D1, and by a current supplied from the auxiliary resonant circuit 6 shown in FIG. In other words, when the switching element SW2 is turned off, the current continues to flow due to the energy stored in the load circuit 5 and the auxiliary resonant circuit 6, and the switching element SW2 is turned off.
The second capacitance component C5 is charged. Here, the energy stored in the load circuit 5 is relatively small, as shown in FIG. 2(c).
Inductance 1. The potential at the connection point between and capacitor C ■. (t z t
+), the constant of the auxiliary resonant circuit 6 is set to the 2171st
If it is set so that the potential Vo' at the connection point between the inductance L' and the capacitor C' rises quickly as shown in (g), the capacitance component C of the SW2
s is immediately charged. As a result, when switching element SW2 is turned off, drive circuit 41.4
The output of r, V c + , V C3 is immediately inverted,
The switching elements SW, , SWj are turned on. In Figure 2 (c) and (h), the time (t
1+), but this is the operation when the auxiliary resonant circuit 6 is not present, and by providing the auxiliary resonant circuit 6, the switching element SW
Since the switching element SWI is immediately turned on after the switching element SWI is turned off at time t1, the voltage V at time t1 in the circuit of FIG. and the current IS1 immediately rises. By repeating the above operation, a sinusoidal current l as shown in FIG. 2(m) flows through the load p of the load circuit 5.
The capacitor C' in the auxiliary resonant circuit 6 is
A current If' flows as follows.

[Embodiment 2] This embodiment shows an example in which the load circuit 5 is resistive like an incandescent light bulb. Therefore, the equivalent circuit of the load circuit 5 is only a resistor R as shown in FIG. It can be expressed as In this case, the operation shown in FIG. 4 is performed. The difference from FIG. 2 is that the current Is of the switching element SW
+ and the current T flowing through the resistor R of the load circuit 5. That is. That is, if the load circuit 5 is resistive, no stored energy is generated in the load circuit.
When the switching element SW2 is turned off, the capacitive component Cs is charged only from the auxiliary resonant circuit 6. As a result, the current Is+ of the switching element SW1 does not go in the opposite direction, and a current corresponding to the on/off state of the switching element SW1 flows through the load circuit 5. Therefore, when the resistive load circuit 5 is used in the conventional configuration in which the auxiliary resonant circuit 6 does not exist, the capacitance component Cs of the switching element SW2 is connected to the resistor R3 from the power source E1.
The switching element S
There was a problem that high-speed operation was not possible because there was a delay equal to the time constant determined by the resistor R5 and the capacitance component Cs from when W2 was turned off until the switching element SW1 was turned on. By using 6,
This problem will be solved. Since the configuration other than the configuration of the load circuit 5 is the same as that of the first embodiment, the explanation will be omitted.

[Embodiment 3] In this embodiment, as shown in FIG.
When W2 is turned off, the capacitive component C5 is charged from the power source E. A series circuit of a pair of resistors R4R9 is connected in parallel to the switching element SW2, and a series circuit of a capacitor C4 and a resistor R6 is connected between both ends of the resistor R5. The base of a transistor Q is connected to the connection point between the capacitor C1 and the resistor R6, and a series circuit between the collector and emitter of the transistor Q1 and a pair of resistors Rt and Rs is connected between both ends of a power supply E. Furthermore, the resistances Rt, R
The base of the transistor Q2 is connected to the connection point of s,
The emitter of the transistor Q2 is connected to the positive electrode of the power source E, and the collector is connected to the switching element S W t via a resistor R. The operation of this configuration will be explained based on FIG. As shown in FIG. 6(b), at time t0, drive circuit 4. When the output rises, the switching element SW
2 is turned on, capacitor C4 is discharged via resistors R4 to R6. Potential at each end of capacitor C4 ■. 4
, V 116 respectively go to 0 as shown in FIG. 6(h) (i>), and the discharge of the capacitor C1 ends at time tel.
1, transistor Q is off, so transistor Q2 is also off. When the switching element SW is turned off at time t1, the capacitance component Cs of the switching element SW2 begins to be charged by the power source E1 via the resistor R1. At this time, a charging current flows to the capacitor C4 via the resistor R1. Furthermore, as shown in FIG. 6 (i>), since the potential at the connection point between the capacitor C4 and the resistor R6 is instantaneously reversed, the transistor Q is turned on at once, and the transistor Q2 is also turned on.As a result, The capacitance component Cs is charged by the power supply E between the emitter and collector of the transistor Q2 and through the resistor R9, and for a short time rM1(tl, -t,)
During this period, charging of the capacitive component C5 is completed. Therefore, as shown in FIG. 6(d), the input voltage v1 of the drive circuit 4I rises, and the switching element S W + is turned on. The charging current to the capacitor C4 decreases as the terminal voltage V of the capacitor C1 increases, and by the time charging is completed at time t12, the transistor Q has turned off.
By repeating the above operations, an alternating current can be caused to flow through the load circuit 5. Also in the configuration of this embodiment, the switching element SW
2 is turned off, the capacitive component Cs is rapidly charged, so that it can be operated at high speed regardless of the state of the load circuit 5.

Embodiment 4 In this embodiment, as shown in FIG. 7, the inductance is reduced compared to the conventional configuration shown in FIG. 18. and a resistor R1°, and a diode D4 and a Zener diode Z connected in parallel to this series circuit.
The difference is that a series circuit with Da is added. In this configuration, by connecting a series circuit consisting of an inductance L4, a resistor R9°, and a switching element SW across the power supply E, when the switching element SW2 is turned off, an inductance is generated and the stored energy is utilized. Thus, the capacitive component C5 is charged. The operation will be explained below using FIG. 8. That is, as shown in FIG. 8(b), when the output V c 2 of the drive circuit 42 rises at time t0 and the switching element SW2 is turned on, the potential ■ at the input terminal of the drive circuit 42 becomes 0. , an increasing current IL4 as shown in FIG. 8(g) flows through the resistor R1° due to the accumulated energy of the inductance, and at time t. The current I L at l
4 is stable. Next, when the switching element SW2 is turned off at time t1, as shown in FIG. 8(g), the current Ii,4 that has been flowing through the inductance L4 tries to continue flowing, so the capacitance component C8 of the switching element SW2 is charged by this current in a short time rrjJ(t++ t+). As a result, the potential (2) at the input terminal of the drive circuit 4I rises, and the switching element SW is turned on. here,
A Zener diode ZD for clamping is provided to prevent the potential VI at the input terminal of the drive circuit 41 from rising excessively due to the energy stored in the inductance L. The energy stored in the inductance is released through the resistor R8° until time t12. By repeating the above operations, an alternating current flows through the load circuit 5.

[Embodiment 5] In this embodiment, as shown in FIG. 9, the Zener diode ZD in the configuration of FIG. A diode D5 is inserted between them. In this configuration, the voltage across the series circuit of the inductance L4 and the resistor R11 is clamped by the diode D. Therefore, the drive circuit 4 with inductance L4. The rise in potential ■1 at the input terminal of diode D4
However, the forward voltage drop of the switching element S
The potential V0 at the connection point between W and the diode D1 is the power supply E.
Since the capacitive component Cs is charged with the energy stored in the inductance L until the voltage becomes approximately equal to the voltage of can do.

Embodiment 6 In this embodiment, as shown in FIG. 10, the series circuit of diode D4 and Zener diode 2D4 in Embodiment 4 is replaced with a resistor R)1. Although the operation of this configuration is similar to that of the fourth embodiment, the explanation will be omitted.

[Embodiment 7] As shown in FIG. 11, in this embodiment, a capacitor C1 is inserted between the inductance and the resistor R1o in the sixth embodiment, and a capacitor C1 is inserted between the resistor R1o and the switching element SW2. A diode D6 is inserted. As shown in FIG. 12(b), the output Vc of the drive circuit 42
2 rises and the switching element sw2 is turned on, the capacitor C1 is charged via the inductance l-24, and a current r as shown in FIG. 12(g) is generated.
1 and 4 flow. When the timekeeper and switching element SW are turned off, the inductance becomes 1. . The current 11.4 that was flowing through the capacitor C4 tries to continue flowing, and the capacitance component Cs of the switching element SW2
charge quickly. As a result, drive circuit 4. The potential V1 at the input end of the switch immediately rises, and the switching element SW1 is turned on by time tll. Thereafter, the energy stored in the inductance L4 and the capacitor C1 is released until the switch-V switching element SW is next turned on at time t. By repeating the above operations, an alternating current flows through the load circuit 5.

[Embodiment 8] As shown in FIG. 13, in contrast to the conventional m configuration shown in FIG.
7, D a are connected in series, and a pair of diodes D9 . Connect the series circuit of D and 0 and connect the diode D? , D s and the connection point of diodes D s and D 1° are connected, and furthermore, a series circuit of an inductance I-9 and a capacitor C1 is connected between both ends of the diode D. It is assumed here that the load circuit 5 has the same configuration as in FIG. As shown in FIG. 14(b), at time t. In the drive circuit 4. When the output Vc of is turned on, the switching element SW2 is turned on, and at the same time, the inductance is
The current flowing in the series circuit with capacitor C1 and capacitor C1 will continue to flow, and will flow to diode D as shown in FIG. 14 (i>). Inductance 17.
and the time t determined by the capacitor C9. When it comes to I,
The current due to the energy stored in the load circuit 5 flows through the diode D.
1 to the switching element SW2, and
A current due to the inductance and the energy stored in the capacitor C9 will flow to the switching element SW2 via the diode D, as shown in 1412(h). That is, the switching element SW,
A current as shown in FIG. 14(g) flows through. On the other hand, even if the switching element SW 2 is turned off at time t, the inductance L, s and the capacitor C
Since the current due to the stored energy with 1 flows through the diode D, the capacitive component Cs is immediately charged by this current. As a result, the potential V at the input end of the drive circuit 41 immediately rises to the switching element SW1.
is turned on. Further, the remainder of the energy stored in the series circuit of inductance L5 and capacitor C1 is released via diode DIo, as shown in FIG. 14(k). When the release of the stored energy is completed at time t12, a current flows through the switching element S W + and the diode D7 into the series circuit of the inductance and the capacitor C7 (see FIG. 14 (J>), and the current flows at time t2 When the switching element SW is turned on again at , the above-mentioned operation is repeated. With this configuration, even if the energy stored by the load circuit 5 is small, as in the first embodiment, the inductance and the auxiliary capacitor C5 are If the energy stored by the resonant circuit is set to be large enough to charge the capacitance component Cs, high-speed operation can be achieved.

[Embodiment 9] As shown in FIG. 15, in this embodiment, an auxiliary resonant circuit 6 consisting of a series circuit of an inductance L6 and a capacitor C6 is connected between both ends of the load circuit 5 with respect to the configuration shown in FIG. 18. This is what I did. With this configuration, it is equivalent to increasing the stored energy of the load circuit 5, so the time from turning off the switching element SW2 to turning on the switching element SW1 can be shortened, and high-speed operation can be performed.

Embodiment 10 In this embodiment, as shown in FIG. 16, in the configuration of Embodiment 1 shown in FIG. It is composed of The gates of both field effect transistors T, , T2 are connected via a switch element S. Further, the drain and source of one field effect transistor T are connected in series to a diode D, and the other field effect transistor T
, is connected between the gate and source of one field effect transistor T. Driver circuit 4. The output of is inputted to the gate of the field effect transistor T via a resistor R1□. According to this configuration, the drive circuit 4. The switch element S is turned on when the output of the transistor rises, and at this time both field effect transistors T, , T2 are operated as a current mirror circuit. That is, at this time, drive circuit 4. The resistor R11 is set so that the potential V at the input end of the resistor R11 becomes 0. As a result, the switching elements SW, , SW are turned off and operate in the same manner as in the first embodiment. When switching element S is turned off after switching elements SW, , SW, are completely turned off, field effect transistor T is turned on completely. According to this operation, a period in which the switching elements SW+, SW3 and the switching element SW2 are turned off at the same time is provided between each on period, and the switching elements SW,
, SW) and the switching element SW2 can be reliably prevented from occurring due to the simultaneous turning on of the switching element SW2.

[Embodiment 11] As shown in FIG. 17, this embodiment is different from Embodiment 5 shown in FIG. This is what I did. The operation is similar to the fifth embodiment. Note that the switching elements sw, sw are not only field effect transistors, but also bipolar transistors with diodes connected in antiparallel to the emitter and collector pins.
Alternatively, a thyristor with diodes connected in antiparallel between the anode and cathode can be used. Further, the oscillation circuit 2 can be easily realized using a commercially available SM circuit (for example, a timer integrated circuit known as 555), and the drive circuits 41 to 4. For this purpose, a buffer that is an integrated circuit may be used.

【Effect of the invention】

As described above, the present invention connects a series circuit of a pair of switching elements and a voltage detection element inserted between both switching elements across a DC power supply, and turns one switching element on and off by a control circuit. With off control,
The other switching element is controlled to be turned on and off so that both switching elements are alternately turned on and off based on the potential at the connection point of the series circuit between the one switching element and the voltage detection element, and In an inverter device that supplies alternating current to the load from the connection point between the switching element and the voltage detection element, when one of the switching elements is turned off, the potential at the connection point with the voltage detection element changes. This device is equipped with a current supply means that shortens the time it takes for the above-mentioned switching element to reach a potential that can turn off the other switching element. Since the guest component is charged by the current supply means, the time required for the potential at the connection point between the switching element and the voltage detection element to reach a potential at which the other switching element can be turned off is shortened. This has the effect of shortening the time from when one switching element is turned off to when the other switching element is turned on, thereby speeding up the switching operation.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing the first embodiment of the present invention, Fig. 2 is an explanatory diagram of the same operation as above, Fig. 3 is an equivalent circuit diagram of a load circuit showing the second embodiment of the present invention, and Fig. 4 is the same as the above. FIG. 5 is a circuit diagram showing the third embodiment of the present invention, FIG. 6 is a diagram explaining the operation of the same H, FIG. 7 is a circuit diagram showing the fourth embodiment of the present invention, and FIG. 8 is a circuit diagram showing the fourth embodiment of the present invention. 9 is a main circuit diagram showing the fifth embodiment of the present invention, FIG. 10 is a circuit diagram showing the sixth embodiment of the present invention, and FIG. 11 is a seventh embodiment of the present invention. Circuit diagram, FIG. 12 is an explanatory diagram of the same operation as above, FIG. 13 is a circuit diagram showing Embodiment 8 of the present invention, FIG. 14 is an explanatory diagram of the same as above, and FIG. 16 is a circuit diagram showing Embodiment 10 of the present invention, FIG. 17 is a circuit diagram showing Embodiment 11 of the present invention, FIG. 18 is a circuit diagram showing a conventional example, and FIG. 19 is the same as above. It is an operation explanatory diagram. DESCRIPTION OF SYMBOLS 1... Control circuit, 5... Load circuit, 6... Auxiliary resonance circuit, Dl... Diode, E... Power supply, SW, SW,... Switching element, l... Load.

Claims (1)

[Claims] (1) A series circuit consisting of a pair of switching elements and a voltage detection element inserted between both switching elements is connected across a DC power supply, and one switching element is controlled on/off by a control circuit, The other switching element is controlled to be on/off so that both switching elements are alternately turned on and off based on the potential at the connection point of the series circuit between the one switching element and the voltage detection element, and the other switching element is controlled to turn on and off. In an inverter device in which alternating current is supplied to the load from the connection point between the element and the voltage detection element, when one of the switching elements is turned off, the potential at the connection point with the voltage detection element is An inverter device comprising current supply means that shortens the time required to reach a potential that can turn off the other switching element.