JPS63117668A - Snubber energy regenerative circuit for inverter - Google Patents

Abstract

PURPOSE:To eliminate an influence of a DC magnetic deviation by connecting a regenerative transformer to the AC output side of a power source two-split inverter. CONSTITUTION:In a snubber energy regenerative circuit for an inverter, snubber capacitors 4a-4b, snubber diodes 5a-5b are provided at an arm element formed of self-arc extinguishing element (GTO) 2a-2b, and flywheel diodes 3a-3b. In this case, a power source two-split inverter 40 is formed of commutation energy absorbing capacitors 21a-21b, transistors 22a-22b, a regenerative transformer 24, etc., and bridge-connected regenerative diodes 25 and a current suppressing impedance 27 are provided. Thus, commutation energy including snubber energy is temporarily absorbed to the capacitors 21a-21b, converted by the inverter 40 to AC, full-wave rectified by the diodes 25 from the transformer 24, and returned to a power source 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inverter device that obtains current power from direct current power, and particularly relates to a snubber energy regeneration circuit for an inverter device that uses self-extinguishing elements as switching elements. It is something.

[Conventional technology]

Figure 4 shows, for example,
gE IAS) 1985 (1', 20-27) Efficient Snubbers 7O Voltage-Source Inpenters) ("EHicientSnubb
ers for Voltage-8source
This is a conventional snubber energy regeneration circuit diagram shown in 1nvertersJ), in which 1 is a DC power supply, 2a and 2b are self-extinguishing elements (hereinafter abbreviated as GTO resistors), and 7 live wheel diodes 3a. , 3b in antiparallel to form an arm element. 4a.

4bi snubber capacitor, 5a, 5bi snubber diode, 6 current limiting reactor, 7 energy regeneration U
T (hereinafter abbreviated as feedback eT) and 8 are regeneration diodes.

Next, the operation will be explained. Now, G 1”0 element 2a
It is assumed that V is conductive and the load current shown in FIG. 4 is flowing in the direction of the arrow. At this time, GTO Yuko 2a
The commutation operation when a full reverse current is passed through the gate of the transistor and turned off will be explained with reference to FIG. First, the same figure (a
) shows the current path immediately after turn-off, and the snubber capacitor 4aH is charged in the direction of the arrow, and the snubber capacitor 4b is discharged in the direction of the arrow. At this time, the current flows in the feedback CT direction, and the other secondary winding 7SICi feedback CT
7 (7) Current flows in each of the illustrated polarities according to the primary and 72nd turns ratio. Thus, when the voltage of the snubber capacitor 4b is discharged to zero, the operation shown in Fig. 85(b) occurs, the flywheel diode 6b becomes conductive, and the energy stored in the current limiting reactor 6 is transferred via the feedback CT7. returned to the power supply n/). Finally, the current in the snubber diode 5a becomes zero and the feedback mode ends. The state is shown in FIG. 5(c). Figure 6(a), f
Load current engineering for bl, fc). is the snubber indicated by the dotted line.
It shows the respective current flows during commutation operation when the GTO resistor 2at is then fired from the state in which the current is supplied through the diode 2bt.

That is, when the GTO element 2a' is ignited, a short circuit current flows in the circuit of the GTO element 2a, the current limiting reactor 6, the snubber diode 5b, and the current of the GTO element 2a becomes the load current I by n%. When the current in the snubber diode 5b reaches zero, the mode shown in FIG. 5(a) is formed. continue,
When the snubber capacitor 4b starts charging, the snubber capacitor 4b starts charging.
Capacitor 4ai discharge starts. When the voltage of the snubber capacitor 4a becomes zero, the snubber diode 5
a becomes conductive, and the mode of bl is formed in the same figure (
In state b), as in Fig. 4, the energy accumulated in the current limiting reactor 6 is returned (, '1'' 7 i
It is returned to the power supply via. Finally, the currents in the snubber diodes 5a and 5b become zero, and the υ commutation is completed in the state shown in FIG. 5 (cl).

[Problem that the invention seeks to solve]

Since the snubber energy regeneration circuit of the conventional inverter device is configured as described above, the current in the primary winding 7P of the feedback CT always flows in a constant direction, and the current flows in the primary winding 7P of the feedback CT in a constant direction. For this reason, the resetting of the feedback CT becomes slow, making it difficult to operate the inverter device at a high frequency. That is, there was a problem that a sufficient reset voltage for the feedback CT could not be secured.

This invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a snubber energy regeneration circuit for an inverter device that can be operated at high frequencies.

[Means for solving inter-vertices]

The snubber energy regeneration circuit of the inverter device according to the present invention comprises an inverter circuit with a power supply divided into two, in which the snubber energy is once absorbed into two series capacitors and used as a new power supply, and the snubber energy is also drained from the inverter. The power is returned to the DC power supply via a transformer (current transformer or transformer). Since it is connected to, it is not affected by DC bias magnetism. [Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the same parts as in FIG. 4 are shown with the same reference numerals, and 21a and 21bi are commutation energy absorbing capacitors, and 22a and 22b are self-extinguishing switching elements, which are shown as transistors here. ing. 23
a, 23bU feedback diode, 24 is regenerative transformer, 2
Regeneration diode bridge-connected to 5, 26.27
H current suppression impedance (reactor or resistance),
40 is a power supply two-split inverter.

Next, the operation will be explained. First, $5 figure (b), 6th
In the final process of commutation in FIG. 4, as shown in FIG. As shown in an equivalent circuit like n
, a pulse current source 30 Ip exists, and this current source is connected to −H
The commutation energy is absorbed by the capacitors 21a and 21b and used as a power source. And power supply 2 split inverter 4
0, is full-wave rectified through this AC output full regenerative current transformer 24, and is fed back to the DC power supply 1.

Here, the operating waveforms of each part are shown in FIG. Pulse current source 30IpH commutation energy absorption capacitor 21a, 2
1bk is charged, and the capacitor voltage is charged as shown in FIG. 3('b). - 10,000, the self-arc-extinguishing switching elements 22a and 22bi are repeatedly turned on and off,
The pulse current source 30Ip is alternately turned on and off at a sufficiently short period of T/2 (the switching period of the TiGTO). At this time, the output current 1° of the power supply 2-split inverter 40 is generated by the commutation energy absorbing capacitors 21a and 21.
An alternating current as shown in FIG. 3(b) flows in accordance with the voltage ec of b. In response to this, the regenerative current if is fed back to the power source as shown in FIG. 4(d). In addition, current suppression impedance 26
゜27 should contain at least one of -1. The absorption capacitor absorbs the energy, converts it to alternating current using a high-frequency inverter that divides the power supply into two, and then performs full-wave rectification through the regenerative transformer, which is then returned to the power supply, making the regenerative transformer smaller and allowing it to be returned to the power supply. In addition to reliably resetting the CTf, the withstand voltage of the flywheel diode can also be lowered, making the device less expensive and having the effect of providing a highly reliable GTO inverter device that can operate at high frequencies.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a GTO inverter device according to an embodiment of the present invention, Fig. 2 is an equivalent circuit diagram of the energy regeneration mode in the embodiment of Fig. 1, and Fig. 3 is an operation waveform diagram of each part in Fig. 2. , FIG. 4 is a circuit diagram of a conventional inverter device, and FIGS. 5 and 6 are explanatory diagrams showing operation modes during turn-off and turn-on in FIG. 4. In the figure, 1 is a DC power supply, 2a and 2b are GTO elements,
3a, 3bH flywheel diode, 4a, 4b are snubber capacitors, 5a, 5b are snubber diodes, 6 is current limiting reactor, 7 is CT for regeneration, 8 is regeneration diode, 21a, 21b is commutated energy Absorption capacitor, 22a, 22b self-extinguishing switching element, 23a, 23b feedback diode, 24
25 is a regenerative transformer, and 25 is a regenerative diode - ≠ 4.2
6.27i is an impedance for current suppression, 60 is a pulse current source, and 40 is a power supply splitting inverter. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Patent applicant: Mitsubishi Electric Corporation Figure 1 ■ 40, Invader Figure 2

Claims (3)

[Claims] (1) An arm element is formed by a self-arc extinguishing element and a flywheel diode connected in antiparallel, and a current limiting reactor is arranged between the positive and negative arm elements with the arm elements arranged on both the positive and negative sides, and each arm In a snubber energy regeneration circuit of an inverter device in which a snubber consisting of a snubber capacitor and a snubber diode is connected to the element,
A two-part power supply inverter is connected between the anode of the positive snubber diode and the cathode of the negative snubber diode of the snubber, and generates an alternating current with a frequency higher than the switching frequency of the self-extinguishing element, and connects the alternating current to a regenerative transformer. A snubber energy regeneration circuit for an inverter device, characterized in that the snubber energy is converted to high voltage through a regeneration diode, connected to a DC power supply through a regeneration diode, and fed back. (2) The inverter is constructed by connecting two DC energy absorbing capacitors in series, and at least two self-extinguishing switching elements using the DC energy absorbing capacitors as a two-divided power supply. A snubber energy regeneration circuit for an inverter device according to claim 1, characterized in that a circuit is formed. (3) A current suppression impedance is connected between the intermediate points of the series connection of the two series-connected commutation energy absorbing capacitors and self-extinguishing switching elements forming an inverter circuit, and the current suppression impedance is 2. A snubber energy regeneration circuit for an inverter device according to claim 1, wherein alternating current flowing through the impedance is detected by a regeneration current transformer and fed back to a regeneration diode.