JP2874225B2 - Converter device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter device, and more particularly, to a converter device connected to a transistor bridge circuit as a load and used as a voltage-type PWM inverter or a voltage-type PWM converter.

[Conventional technology]

Conventionally, in this type of converter device, there are two methods for supplying a DC voltage to a control power supply device for a control circuit. For example, as shown in FIG. 3 and FIG.
In the case of the M inverter device, in the case of FIG. 3, an AC voltage input from the outside is rectified by the control power supply diode bridge 6 and a DC voltage is supplied to the control power supply device 7.
The capacitor 12 is used to prevent a power failure of the AC power supply, and supplies a voltage to the control power supply 7 during a certain time during the power failure. In the case of FIG. 4, a DC voltage is supplied from the main circuit DC bus 4 to the control power supply 7. In any case, the smoothing capacitor 3 for shaping the voltage waveform between the positive and negative sides of the DC bus 4 is provided, and the contactor 5 on the input side of the diode bridge circuit 1 is charged when the capacitor 3 is not charged. When the power is turned on and the AC input is connected, an excessive charging current flows and destroys the elements of the bridge circuit.To suppress this, first close the charging relay contacts 13 and 14 when turning on the power, The capacitors 3 are charged by inputting current limiting resistors 15 and 16 in series. Contact 1 after capacitor voltage is established
Open 3,14, turn on contactor 5 and start operation.

[Problems to be solved by the invention]

In the case of the conventional converter device described above, in the case of the device shown in FIG. 3, a large-capacity power failure countermeasure capacitor corresponding to the capacity of the control power supply device is provided at the input side thereof in order to hold the output of the control power supply device when the AC power supply fails. In the case of the apparatus shown in FIG. 4, since the main circuit DC bus is used as a power source, it is impossible to operate only the control power supply apparatus by shutting off the main circuit power supply. There is.

An object of the present invention is to solve the above-mentioned drawbacks of the conventional device and to provide a converter device capable of always supplying power to a control power supply device from an input power supply side and from a DC bus side. .

[Means for solving the problem]

In the converter device according to the present invention, the positive output terminal of the control power supply rectifier circuit and the positive DC bus, and the negative output terminal of the control power supply rectifier circuit and the negative DC bus are connected, respectively. On either side of the circuit, a charging circuit for the smoothing capacitor having a charging current limiting resistor inserted in series and a charging relay contact for opening and closing the circuit; the current limiting resistor and the contact When the battery is inserted on the positive side of the charging circuit, the direction from the DC bus to the rectifying circuit for the control power supply is set to the forward direction. It has a current limiting resistor inserted in series and a diode connected in parallel with the contact, with the direction toward the bus bar being the forward direction.

[Action]

The converter device of the present invention charges the smoothing capacitor via the current limiting resistor by the rectifier circuit for the control power supply at the start of operation and before the contactor of the AC power supply is turned on. Supply a DC voltage to the load. During operation, power is supplied to the control power supply by the rectifier circuit for control power supply, and power can be supplied from the smoothing capacitor to the control power supply via the diode even if the AC power supply fails. In addition, even when the contactor is opened and the converter device main circuit is stopped, power can be supplied to the control power device by the control power supply rectifier circuit, and only the control circuit can be operated.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the converter device of the present invention.

In this embodiment, a voltage-type PWM inverter device is constituted by using a transistor bridge circuit 2 as a load, and a diode bridge circuit 1 is inputted from a three-phase AC power supply via a contactor 5, rectified, and then rectified. A DC voltage is supplied to the transistor bridge circuit 2 through the DC bus 4, and the smoothing capacitor 3 is connected between the positive and negative sides of the DC bus 4. The control power supply diode bridge 6 connected to one phase of the AC power supply has its positive output terminal connected to the positive side of the DC bus 4 and its negative output terminal connected to the negative side of the DC bus 4. A DC voltage is supplied to a control power supply device 7 which forms a charging circuit for the smoothing capacitor 3 and is a control circuit power supply for the inverter device. On the positive side of the charging circuit, a current limiting resistor 9 for limiting charging current and a contact 8 of a charging relay for opening and closing the charging circuit are inserted in series.
The diode 10 bypasses the current limiting resistor 9 and the contact 8 with the direction from the DC bus side to the control power supply diode bridge side being the forward direction.

 Next, the operation of this embodiment will be described.

First, when the power is turned on, since the smoothing capacitor 3 is not charged and the contactor 5 is not closed, the voltage cannot be supplied from the DC bus 4 to the control power source 7.
Diode bridge 6 for control power supply from external AC power supply
Is supplied with a DC voltage. This circuit also functions as a charging circuit for the smoothing capacitor 3. When the contact 8 of the charging relay is closed, a charging current flows through the current limiting resistor 9 to the smoothing capacitor 3. When the voltage of the smoothing capacitor 3 becomes sufficiently high, the contactor 5 is closed and the operation state is started.

Next, when the AC power supply is cut off due to a power failure or the like, a voltage is supplied from the smoothing capacitor 3 to the control power supply device 7 through the diode 10, and the operation of the control circuit can be continued.

In this embodiment, the case of the voltage PWM inverter device has been described. However, as shown in FIG. 2, a transistor bridge circuit 11 composed of an element having self-isolation capability such as a transistor is connected in antiparallel with the diode bridge circuit 1. Application to a voltage type PWM converter is also possible.

[Effects of the Invention] As described above, the present invention installs a charging circuit for a smoothing capacitor between the control power supply rectifier circuit and the DC bus, so that the control power supply device can be connected to an external AC power supply. ,
By making it possible to supply voltage from the internal smoothing capacitor side, there is no need for a large-capacity capacitor for power failure countermeasures for the control circuit, and the operation of the control circuit while the main circuit is stopped. There is an effect that enables.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a converter device according to an embodiment of the present invention, FIG. 2 is a diagram showing a main circuit configuration of a voltage source PWM converter to which the present embodiment can be applied, and FIGS. It is a circuit diagram which shows the example of a structure of the conventional converter device, respectively. DESCRIPTION OF SYMBOLS 1 ... Diode bridge circuit, 2 ... Transistor bridge circuit, 3 ... Smoothing capacitor, 4 ... DC bus, 5 ... Contactor, 6 ... Diode bridge for control power supply, 7 ... Control power supply device, 8 ... ... contact, 9 ... current limiting resistor, 10 ... diode, 11 ... transistor bridge circuit.

Claims (1)

(57) [Claims] 1. A diode bridge circuit for rectifying an AC voltage inputted from the outside via a power switch and outputting a DC voltage to a DC bus, and a diode bridge circuit connected between the positive and negative DC buses for smoothing the output waveform. A control power supply for the control circuit, and a control power supply rectification circuit for supplying a DC voltage from an external AC power supply to the control power supply. Any one of the circuits connected between the positive output terminal and the positive DC bus, and between the negative output terminal of the control power supply rectifier circuit and the negative DC bus, is inserted in series. A charging circuit for the smoothing capacitor having a current limiting resistor for charging current and a contact for a charging relay for opening and closing the circuit; and the current limiting resistor and the contact are inserted on the positive side of the charging circuit. When Is the forward direction from the DC bus to the rectifier circuit for the control power supply, and when inserted on the negative side of the charging circuit, the forward direction is the direction from the rectifier circuit for the control power supply to the DC bus, and A converter device comprising a flow resistor and a diode connected in parallel with a contact.