JPS60234474A - Inverter device with regenerative converter circuit - Google Patents

Abstract

PURPOSE:To improve the reliability by connecting a unidirectional element in series with a regenerative converter circuit, thereby eliminating a current limiting resistor and a relay. CONSTITUTION:An inverter circuit 11 is provided between an AC power source 1 and a load motor 9. The inverter circuit 11 has a power reactor 3 including rectifiers 3a-3f, and a power inverter 6 including switching means 6a-6f, and has a regenerative converter circuit 13 aligned between both. In this case, a rectifying diode 10 of a unidirectional element is inserted in series with the connection of the circuit 13 to the circuit 11. Thus, when the power source 1 is turned ON in the state that charge is not stored in a smoothing capacitor 5, a rush current limited by the current limiting resistor 4a is charged in the capacitor 5, and the resistor 4a is shortcircuited by a relay 2a after the charge is completed. The current is stopped by the diode 10 in the circuit 13.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The small invention relates to an inverter device that drives an induction motor, an AC servo motor, a DC motor, etc., and particularly has a regenerative converter circuit that regenerates regenerative energy from the motor into a power source. It relates to an inverter device.

[Background of the invention]

An example of a conventional inverter device will be explained with reference to FIG.

In Fig. 1, 1 is an AC power supply, 9 is a motor as a load, 11 is an inverter circuit, and 12 is a regenerative converter circuit. Here, the inverter circuit 11 includes an 11M converter 3 that converts alternating current to direct current, a smoothing capacitor 5 that smoothes the direct current, and an inverse converter 6 that converts direct current to alternating current. The +1A long-term converter 3 has rectifying elements 8a to 3f.
The inverse converter 6 includes switching elements 68 to 68.
6f and flywheel diodes 7a to 7f. A current-limiting resistor 4a and a relay 2a that short-circuits the current-limiting resistor due to a delay in operation are connected to the DC side of the forward converter 3.

The regenerative converter circuit 12 includes an AC reactor 8, switching elements 6g to 61, and a flywheel diode 7g.
- 71 are connected to the AC side of the forward converter 8 and the DC side of the inverse converter 6 by inserting a current limiting resistor 4b and a relay 2b.

In an inverter device having a regenerative converter circuit configured as described above, the flow of the inrush whistle at startup passes through two circuits, the current limiting resistor 4a of the inverter circuit 11 and the current limiting resistor 4b of the regenerative converter circuit 12, and the motor 9. trying to flow to Here, since this rush current is limited by the current limiting resistor 4a14b, it has a relatively small value. When the smoothing capacitor 5 is completely charged, the current limiting resistors 4a, 4b are short-circuited by the relays 2a, 2b.

However, in the conventional inverter device W1 having such a configuration, two relays 2a, 2 are used to short-circuit the current limiting resistor 4a14b.
b is thick, and the wear of the contacts of these relays 2a and 2b reduces reliability, and the heat generated by the current limiting resistor 4b increases the temperature rise of the switching means 6g to 61.

[Purpose of the invention]

An object of the present invention is to provide an inverter device with a power regenerative converter that has a small current limiting resistor and relay in a regenerative converter circuit and is highly reliable.

[Summary of the invention]

The present invention is characterized by an inverter circuit including a forward converter for converting alternating current into direct current, a capacitor for smoothing the direct current, and an inverse converter for converting direct current to alternating current;
'to the AC side of the converter and the 16 flow side of the inverse converter:
Subsequently, in an inverter device having a single regenerative converter circuit consisting of a single regenerative converter circuit that regenerates regenerative energy from the mode to the noodles and the source, a unidirectional element is connected in series on the DC side of the regenerative converter. It is possible to block the inrush current flowing through the regenerative converter circuit when the mode is started.The regenerative converter circuit also has a relay θ- which has a contact point between the connection with the inverter circuit and a light heat source. It is possible to extend the lifespan and reduce the amount of heat generated per unit without using a current limiting resistor.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG. In Figure 2, the same parts as in Figure 1 are marked with the same sign (=t).

Here, an inverter circuit 11 is connected between the AC power supply 1 and the motor 9, which is a load. This inverter circuit 11 includes a converter 4q/unit 3 consisting of rectifying elements 3a to 3f,
It consists of switching means 6a to 6f and an inverse converter 6 consisting of flywheel diodes 7a to 7f, and a smoothing capacitor 5 is provided between these 111 converters 3 and the inverse converters 4 and 6. A regenerative converter circuit 13 is connected to the alternating current (Iil) of the forward converter 3 and the inverse converter 6010 stream side in series with the forward converters 3 and 31.

Here, the present invention resides in that a unidirectional element such as a rectifier diode IO is inserted in series between the regenerative converter circuit 13 and the inverter circuit 11.

The operation of the inverter device having the regenerative converter circuit configured in this manner will be explained below. Figure 3 shows power supply 1 and
A time chart of smoothing capacitor 5 and relay 2a is shown. When the AC power supply 1 is turned on with no electric charge charged to the smoothing capacitor 5, the rush current limited by the current limiting resistor 4a charges the smoothing capacitor 5, and when charging is completed, the current limiting resistor is charged by the relay 2a. 4a is shorted. Due to the rectifier diodes 10 connected in series with the 13 regenerative converter circuits, the current β old F is cut off and does not flow. In other words, the rush current to the motor 9 is reduced.

In addition, since the rectifier diode IO is connected so that the motor 9 is in the forward direction during regenerative operation, it can be used as a regenerative converter! There is no problem with Iro 1 in the t9 work.

Therefore, according to this embodiment, the rectifier diode 1 is connected to the connection between the inverter circuit 11 and the regenerative converter circuit 12.
Since 0 is inserted in series, the temperature rise of the switching elements can be lowered because there is no heat generation due to the current limiting resistor compared to the conventional inverter device which is connected using the current limiting resistor hl) 4@ and the relay 24. Reliability is also improved since there are no bulky relays.

〔Effect of the invention〕

According to the present invention, there is an inverter circuit having a smoothing capacitor between a forward converter that converts alternating current to direct current and an inverse converter that converts direct current to alternating current; A regenerative Humberta circuit is connected between the side and the DC side of the inverter, and a unidirectional element is connected in parallel with this regenerative converter circuit. It is possible to block the current flowing to the wrong side, and it has the effect of operating the regenerative converter circuit only when the regenerative jM (JM) is turned on.Also, compared to the conventional inverter device that connects the regenerative converter circuit by adding a relay and a current limiting resistor. Since there is no heat generation due to the current limiting resistor, the temperature rise of the switching element can be reduced, and the number of relays having contacts is reduced, so reliability can be improved.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a conventional inverter device, Fig. 2 is a diagram showing an inverter and associated circuit structure bv showing an embodiment of the present invention, and Fig. 3 is a tie 11 circuit diagram explaining the operation of Fig. 2. = G. 3 is a forward converter, 5 is a smoothing capacitor, 6 is an inverse converter, 1
0 is a rectifier diode which is a unidirectional element, 11 is an inverter circuit, and 12.13 is a regenerative converter circuit. Representative Patent Attorney Akio Takahashi 1 -----111-----72r No. 3 [21 (of

Claims (1)

[Claims] There is an inverter circuit comprising a forward converter for converting alternating current into direct current, a smoothing capacitor for smoothing the direct current, and an inverse converter for converting the direct current to direct current, In an inverter device having a regenerative converter circuit connected between the alternating current side of the forward converter and the direct current side of the inverse converter, a unidirectional element is inserted and connected in series to the direct current side of the regenerative converter circuit. An inverter device having a regenerative converter circuit characterized by: