JP3328031B2 - Snubber energy regeneration type partial resonance circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snubber energy regenerating partial resonance circuit used in a semiconductor power conversion device or the like composed of a self-extinguishing element such as a GTO (gate turn-off thyristor).

[0002]

2. Description of the Related Art A semiconductor power conversion circuit such as an inverter device configured by applying a self-arc-extinguishing element such as a GTO has improved efficiency, downsized the device, improved power supply power factor, and improved harmonics. There are advantages such as suppression of These days, faster,
A large-capacity self-extinguishing element has been realized, various proposals have been made, and the development of application circuits thereof has been actively progressing.

[0003]

The loss that occurs during a single turn-off of a self-arc-extinguishing element is largely determined by the value of the current when the element is turned off. Further, since the number of times of turn-off is equal to the switching frequency of the element, the turn-off loss is determined by the current flowing through the element and the switching frequency of the element.

In general, when a GTO element is used,
A snubber circuit is provided to prevent overvoltage applied to both ends of the GTO element. The loss of the snubber circuit is m ・ C ・ E ²・
It is represented by f. Here, m is a proportional constant and depends on the circuit. C is the snubber capacitor capacity, E is the snubber capacitor voltage, and f is the frequency. As is clear from this equation,
The loss of the snubber circuit is also largely determined by the snubber capacitor voltage and frequency and the snubber capacitor capacitance.

In recent years, power converters have been increasing in capacity, and the need to increase the switching frequency of elements has been increasing in order to improve waveforms such as suppression of harmonics. In such a case, the turn-off loss of the element and the loss of the snubber circuit increase, and in order to cope with this, it is necessary to increase the size of the cooling device, so that problems such as deterioration in maintainability and increase in cost have not become noticeable. I can't get it.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems, and to reduce the turn-off loss and the loss of the snubber circuit, and to further increase the speed and power capacity of future devices. It is an object of the present invention to provide a snubber energy regeneration type partial resonance circuit that can cope with an improvement in the performance of a converter or the like.

[0007]

According to the first aspect of the present invention, a cathode of a first feedback diode and a first snubber are connected to an anode of a first self-extinguishing element. A DC positive terminal is derived from a first connection point connecting the anode of the diode and the cathode of the first diode, and the anode of the first feedback diode and the first snubber capacitor are connected to the cathode of the first self-extinguishing element. An AC terminal is derived from a second connection point where one end of the first snubber capacitor is connected to one end of the first reactor, one end of the second reactor, and one end of the second self-extinguishing element. A first terminal of the first auxiliary switch is connected to a third connection point between the terminal and the cathode of the first snubber diode, and a second terminal of the first auxiliary switch is connected to the other end of the first reactor. Terminal and second diode A cathode is connected, a cathode of a second feedback diode and one end of a second snubber capacitor are connected to an anode of the second self-extinguishing element, and a second feedback is connected to a cathode of the second self-extinguishing element. A DC negative terminal is derived from a fourth connection point connecting the anode of the diode, the cathode of the second snubber diode, and the anode of the second diode, and the first terminal of the second auxiliary switch is connected to the other end of the second reactor. Is connected to the anode of the first diode, and the second connection point of the second auxiliary switch is connected to a fifth connection point where the other end of the second snubber capacitor is connected to the anode of the second snubber diode.
Is a snubber energy regenerating type partial resonance circuit configured by connecting the above terminals.

According to a second aspect of the present invention, a cathode of a first feedback diode and an anode of a first snubber diode are connected to an anode of a first self-extinguishing element. A DC positive terminal is derived from a first connection point connecting the cathode of the diode No. 5 and the cathode of the seventh diode, and the anode of the first feedback diode and the first terminal are connected to the cathode of the first self-extinguishing element. One end of the snubber capacitor, the second terminal of the second auxiliary switch, the anode of the second self-extinguishing element, the cathode of the second feedback diode, one end of the second snubber capacitor, and the third auxiliary switch. An AC terminal is derived from a second connection point to which the first terminal is connected, and the anode of the second feedback diode, the cathode of the second snubber diode, and the tenth die are connected to the cathode of the second self-extinguishing element. Deriving a DC negative terminal than the third connection point connecting the anode and the anode of the eighth diode over de,
One end of the first reactor and the cathode of the eighth diode are connected to the second terminal of the first auxiliary switch, and the other end of the first reactor and the sixth terminal are connected to the first terminal of the second auxiliary switch. connect the anode of the diode, connecting the cathode of the sixth diode to the anode of the fifth diode, the first auxiliary switch
A first terminal, a cathode of a first snubber diode, and a first terminal.
A fourth auxiliary switch connected to the other end of the snubber capacitor
One end of the second reactor is connected to the first terminal of the
And the second terminal of the third auxiliary switch
The other end of the second reactor and the cathode of the ninth diode
Connect the cathode of the tenth diode to the ninth diode
Connected to the anode and the second terminal of the fourth auxiliary switch and the other end of the second snubber capacitor anode of the second snubber diode connected, the sum of the forward voltage of the fifth and sixth diode Is larger than the sum of the forward voltages of the second auxiliary switch and the first feedback diode, and the sum of the forward voltages of the ninth and tenth diodes is equal to the third auxiliary switch and the second feedback diode. A snubber energy regenerating partial resonance circuit characterized in that the partial resonance circuit is configured to have a value larger than the sum of the forward voltages.

[0009]

According to the first and second aspects of the present invention, the current of the main switching element at the time of turn-off can be reduced, thereby reducing the turn-off loss of the main switching element. According to the first and second aspects of the present invention, the last surplus of the snubber energy used for reducing the turn-off loss is regenerated to the main circuit, so that the snubber loss can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a snubber energy regeneration type partial resonance circuit according to a first embodiment of the present invention. This first
In the configuration of the embodiment, there is no ability to reduce the turn-off loss, and the configuration is mainly limited to the capability to reduce the snubber loss due to the regeneration of the snubber energy to the main circuit.

FIG. 1 shows a circuit for one phase of the inverter. AC is an AC terminal, P is a DC positive terminal, N is a DC negative terminal, 1U and 1X are first and second self-extinguishing elements, for example, a main switching element composed of a GTO (gate turn-off thyristor), 2U, 2X is the first
The second feedback diode, 3U, 3X is the first,
The second snubber diodes 4U, 4X are first and second snubber capacitors.

5U, 5X are first and second reactors, 6
U and 6 are first and second X auxiliary switching elements (transistors in this case), and 7U and 7X are first and second diodes, which constitute a snubber energy regeneration type partial resonance circuit.

Hereinafter, this configuration will be described. A DC positive terminal is connected to the anode of the first self-extinguishing element 1U from a first connection point where the cathode of the first feedback diode 2U, the anode of the first snubber diode 3U and the cathode of the first diode 7U are connected. P is derived.

The first self-extinguishing element 1U has the first
Of the feedback diode 2U, one end of the first snubber capacitor 4U, one end of the first reactor 5U, one end of the second reactor 5X, and the second self-turn-off element 1
An AC terminal AC is derived from a second connection point to which the X anode is connected.

The other end of the first snubber capacitor 4U and the first
The first terminal (here, the collector) of the first auxiliary switch 6U is connected to the third connection point to which the cathode of the snubber diode 3U is connected, and the first terminal is connected to the other end of the first reactor 5U.
Terminal (here, emitter) of auxiliary switch 6U
And the cathode of the second diode 7X, the cathode of the second feedback diode 2X and one end of the second snubber capacitor 4X are connected to the anode of the second self-extinguishing element 1X, A DC negative terminal N is derived from a fourth connection point where the anode of the second feedback diode 2X, the cathode of the second snubber diode 3X, and the anode of the second diode are connected to the cathode of the arc-shaped element 1X.

A first terminal (collector in this case) of the second auxiliary switch 6X is connected to the other end of the second reactor 5X.
Of the second auxiliary switch 6X is connected to the fifth connection point where the other end of the second snubber capacitor 4X is connected to the anode of the second snubber diode 3X.
(Here, the emitter) are connected.

The operation and effect of the first embodiment configured as described above will be described below with reference to FIG. 2 (operation waveform diagram of each part in FIG. 1). 2A shows the gate voltage of GTO1U, FIG. 2B shows the base signal of transistor 6U,
(C) shows the gate voltage of the GTO1X, (d) shows the base signal of the transistor 6X, and (e) shows the snubber capacitor 4
U, (f) the current of reactor 5U, (g)
Indicates each mode.

Now, a point in time when GTO1U is turned on is represented by t.
Set to 0. At this time, it is assumed that the snubber capacitor 4U is fully charged. When the auxiliary switch 6U is turned on at a time t1 after a short time from the time t0,
The charge of the snubber capacitor 4U is 4U-6U-5U-4U
Discharge mode (1) in which discharge takes place along the path.

At the time point t2 when the electric charge of the snubber capacitor 4U moves to the reactor 5U, a recirculation mode (2) in which the electric current recirculates along a path of 6U-5U-2U-3U. Further, when the auxiliary switch 6U is turned off at time t3, 5U
The snubber energy stored in is 7X-5-2U
The power is regenerated to the power supply side through the path, and a regeneration mode (3) is set.

As described above, the GTO 1U,
1X current, thereby reducing GTO1U, 1X
Turn-off loss can be reduced. further,
The snubber loss can also be reduced by regenerating the surplus remaining at the end of the snubber energy used for reducing the turn-off loss to the main circuit.

FIG. 3 shows a second embodiment of the present invention. In the second embodiment, in addition to the snubber energy reduction function of the first embodiment, a turn-off loss reduction capability is provided. A transistor is added as the second auxiliary switching element 15U, and Sixth diode 13
U, 13 are added, and the third auxiliary switching element 15X is added.
A ninth and tenth diodes 14X and 14 are added, and a specific configuration thereof will be described below.

The cathode of the first feedback diode 2U, the anode of the first snubber diode 3U, the cathode of the fifth diode 13U, and the cathode of the seventh diode 7U are connected to the anode of the first self-extinguishing element 1U. The DC positive terminal P is derived from the first connection point.

The cathode of the first self-extinguishing element 1U is connected to the anode of the first feedback diode 2U, one end of the first snubber diode 3U and the second of the second auxiliary switch 15U.
(Here the emitter) and the second self-extinguishing element 1
An AC terminal AC from a second connection point where the anode of X, the cathode of the second feedback diode 2X, one end of the second snubber capacitor 4X and the first terminal (collector in this case) of the third auxiliary switch 15X are connected. Is derived.

The anode of the second feedback diode 2X, the cathode of the second snubber diode 3X, the anode of the tenth diode 14 and the anode of the eighth diode 7X are connected to the cathode of the second self-extinguishing element 1X. The DC negative terminal N is derived from the third connection point.

One end of the first reactor 5U and the cathode of the eighth diode 7X are connected to the second terminal (here, the emitter) of the first auxiliary switch 6, and the second auxiliary switch 1
The other end of the first reactor 5U and the anode of the sixth diode 13 are connected to the first terminal (collector in this case) of the 5U, and the cathode of the sixth diode 13 is connected to the fifth diode 1
3U anode connected to the second auxiliary switch 15X.
Is connected to one end of the second reactor 5X and the cathode of the ninth diode 14X, and the other end of the second reactor 5X is connected to the anode of the seventh diode 7U and the fourth auxiliary switch 6X. Of the fourth auxiliary switch 6X, the other end of the second snubber capacitor 4X, and the anode of the second snubber diode 3X. Then, the first terminal (collector in this case) of the first auxiliary switch 6U, the cathode of the first snubber diode 3U and the other end of the first snubber capacitor 4U are connected, and the fifth and sixth diodes 1U are connected.
The sum of the forward voltages of 3U and 13 is the second auxiliary switch 1
5U and a value slightly larger than the sum of the forward voltages of the first feedback diode 2U, and the sum of the forward voltages of the ninth and tenth diodes 14X and 14 is determined by the third auxiliary switch 15X and the second feedback switch. It is configured as a value slightly larger than the sum of the forward voltages of the diode 2X.

The operation and effect of the second embodiment shown in FIG. 3 will be described below with reference to FIG. FIG. 4 (a) to (g)
Shows waveforms of respective portions of the same portion as FIG. The auxiliary switch 15U has the same base signal as 6U, 15X and 6X. A point in time when GTO1U turns off is defined as t3. Go back a little time from this t3, and
When the auxiliary switches 6U and 15U are turned on at the same time, the t1
The electric charge of the snubber capacitor 4U, which has been fully charged before, becomes the discharge mode (1) in which the electric charge is discharged through the path of 4U-6U-5U-15U-4U. At time t2 when the electric charge of the snubber capacitor 4U shifts to the reactor 5U, 5U-1
The reflux mode (2) is a reflux mode in which reflux is performed through a route of 5U-2U-3U-6U-5U. With this partial resonance loop current, GT
GTO1U is turned off at time t3 from the value obtained by subtracting the current of O1U, the turn-off loss is reduced, and the remaining snubber energy is finally turned off at time t4 by turning off auxiliary switches 6U and 15U at the same time. -5U
It regenerates to the power supply through the path of -13-13U. The snubber capacitor 4U of the GTO 1U that is turned off during the regeneration mode (3) absorbs energy due to the inductance of the wiring and acts to prevent an overvoltage applied to the GTO element.

This second embodiment differs from the first embodiment in that
The snubber regenerating circuit does not use the feedback diode 2U of the GTO 1U, but has independent diodes 13, 13
U, 7X, the snubber energy transferred to the reactor 5U, as long as the auxiliary switches 6U, 15U are turned off, passes through the diodes of 13, 13U, 7X, and becomes the switch state of the GTO1U arm. Independent
It can regenerate snubber energy to the power supply. Therefore, the current of the GTO 1U is changed to the partial resonance loop current 1U-3U.
GTO1U is turned off from the value subtracted by -6U-5U-15U-1U, the turn-off loss is reduced, and the last remaining snubber energy is regenerated by turning off auxiliary switches 6U and 15U simultaneously. be able to. In the second embodiment shown in FIG. 3, two diodes 13 and 13U are connected in series because a value slightly larger than the sum of the forward voltages of the transistor 15U and the feedback diode 2U is set to the reflux mode. This is to prevent the flow in (2). Also, the first,
In the second embodiment, the GTO is used as the main switching element and the transistor is used as the auxiliary switching element. However, any element can be used as long as it is a self-extinguishing element.

[0028]

According to the present invention, the problem of the turn-off loss of the self-extinguishing element constituting the power conversion circuit and the like is reduced by the partial resonance circuit, and the snubber energy is used as the energy source of the partial resonance circuit. A snubber energy regenerating type partial resonance circuit that has the effect of reducing the turn-off loss of the main switching element and the snubber loss without providing an energy source, and also capable of regenerating the last remaining snubber energy to the main circuit. it can.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a snubber energy regeneration type partial resonance circuit according to the present invention.

FIG. 2 is a waveform chart for explaining a first operation and effect.

FIG. 3 is a circuit diagram showing a second embodiment of a snubber energy regeneration type partial resonance circuit according to the present invention.

FIG. 4 is a waveform chart for explaining the operation and effect of FIG. 3;

[Explanation of symbols]

1U, 1X ... main switching element, 2U, 2X ... feedback diode, 3U, 3X ... snubber diode,
4U, 4X: snubber capacitor, 5U, 5X: reactor, 6U, 6X: auxiliary switching element, 7U, 7X ...
Diodes, 13U, 13, 14X, 14 ... diodes, 15U, 15X ... auxiliary switching elements.

Claims (2)

(57) [Claims] 1. A DC positive terminal from a first connection point where a cathode of a first feedback diode, an anode of a first snubber diode, and a cathode of a first diode are connected to an anode of a first self-extinguishing element. And the anode of the first self-turn-off element is connected to the anode of the first feedback diode, one end of the first snubber capacitor, one end of the first reactor, one end of the second reactor, and the second self-extinguishing device. An AC terminal is derived from a second connection point to which the anode of the arc-shaped element is connected, and the first terminal is connected to the first terminal.
The first terminal of the first auxiliary switch is connected to a third connection point between the other end of the snubber capacitor and the cathode of the first snubber diode, and the first terminal is connected to the other end of the first reactor.
Connecting the second terminal of the auxiliary switch to the cathode of the second diode, connecting the cathode of the second feedback diode and one end of the second snubber capacitor to the anode of the second self-extinguishing element, A second negative electrode is derived from a fourth connection point where the anode of the second feedback diode, the cathode of the second snubber diode, and the anode of the second diode are connected to the cathode of the self-extinguishing element 2; Fifth connection in which the first terminal of the second auxiliary switch and the anode of the first diode are connected to the other end of the reactor and the other end of the second snubber capacitor is connected to the anode of the second snubber diode. A snubber energy regenerating partial resonance circuit constituted by connecting a second terminal of a second auxiliary switch to a point. 2. A first self-arc-extinguishing element having an anode connected to a cathode of a first feedback diode, an anode of a first snubber diode, a cathode of a fifth diode, and a cathode of a seventh diode. A positive terminal of the first self-extinguishing element is connected to the anode of the first feedback diode, one end of the first snubber capacitor, and the second terminal.
The second terminal of the auxiliary switch, the anode of the second self-extinguishing element, the cathode of the second feedback diode, one end of the second snubber capacitor, and the first terminal of the third auxiliary switch. An AC terminal is derived from the connection point of No. 2 and the anode of the second feedback diode, the cathode of the second snubber diode and the first are connected to the cathode of the second self-turn-off element.
A DC negative terminal is derived from a third connection point connecting the anode of the diode 0 and the anode of the eighth diode, and one end of the first reactor and the eighth diode are connected to the second terminal of the first auxiliary switch. The other end of the first reactor and the anode of the sixth diode are connected to the first terminal of the second auxiliary switch, and the cathode of the sixth diode is connected to the anode of the fifth diode. And the first auxiliary switch
A first terminal, a cathode of a first snubber diode, and a first terminal.
Connected to the other end of the snubber capacitor, the first terminal of the fourth auxiliary switch is connected to the second reactor
One end is connected to the anode of the seventh diode, and a third auxiliary switch is connected.
The other terminal of the second reactor and the ninth terminal are connected to the second terminal of the switch.
Connect the cathode of the diode and the cathode of the tenth diode
Is connected to the anode of the ninth diode, the second terminal of the fourth auxiliary switch, the other end of the second snubber capacitor, and the second terminal.
The sum of the forward voltages of the fifth and sixth diodes is greater than the sum of the forward voltages of the second auxiliary switch and the first feedback diode; A snubber energy regenerating partial resonance circuit, wherein the sum of the forward voltages of the ten diodes is larger than the sum of the forward voltages of the third auxiliary switch and the second feedback diode.