JPH01308170A - Charging circuit for inverter apparatus - Google Patents

Abstract

PURPOSE:To miniaturize an apparatus and reduce its cost by constituting a power rectifier through diode elements and thyristor elements and by phase- controlling initial charging of a DC link part capacitor through one thyristor element. CONSTITUTION:A power rectifier 1 for converting three-phase AC power into DC power is constituted as a polyphase full-wave rectifying hybrid-bridge circuit by thyristor elements 2-U to 2-W and diode elements 2-X to 2-Z. A DC link part capacitor 4 is connected and a power inverter 5 is provided between said positive and negative side output terminals 2, 3. This apparatus is further equipped with a thyristor element-firing power circuit 6, a thyristor gate current- limiting resistor 7, switching elements 8, 9 for said elements 2-U to 2-W, insulating transformers 10, 11, and a phase control circuit 12. At the time of initial charging of the DC link part capacitor 4, thus, the bridge circuit of the power rectifier 1 controls the switching elements 8, 9 by said phase control circuit 12 to turn ON one thyristor element first. Then, after completion of charging, other elements are turned ON to start normal operation.

Description

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

The present invention relates to a charging circuit for an inverter device that receives AC power as input.

[Conventional technology]

FIG. 4 is a circuit diagram of a conventional forward converter disclosed in, for example, Japanese Utility Model Application Publication No. 61-165093, and in the figure,
30 is a forward converter formed into a three-phase bridge by thyristor elements 31 to 36, 37 is an AC power supply, 38 to 43 are gates PT (pulse transformers), and a gate signal is output from a thyristor gate circuit 44. Next, the operation will be explained. First, the switch MC is turned on and the AC type 'ti, 37 is turned on to the forward converter 30. Subsequently, a gate signal is output from the thyristor gate circuit 44 to each thyristor element 31 via the PTs 38 to 43.
-36, the AC power source 37 is converted to a DC power source, and the DC link capacitor 45 is charged. When the forward converter 30 is composed of thyristor elements 31 to 36 as shown in the figure, the gate circuits are of the PT type and are insulated from each other. Further, in order to suppress the rush current to the DC link capacitor 45, some form of charging current limiting resistor (not shown) is generally provided.

[Problem to be solved by the invention]

Since the charging circuit of the conventional inverter device is configured as described above, a charging current limiting resistor and a small capacity contactor are installed, or all the elements constituting the forward converter 30 are thyristor elements 31 to 36. Therefore, it is necessary to install the thyristor gate circuit 44 corresponding to the number of thyristors, which poses the problem of increasing the size and price of the inverter device. In addition, as another approximation technology, “Zyristor Practical Handbook JP”
74 (published by Ohmsha on September 30, 1978). This invention was made to solve the above-mentioned problems, and the number of thyristor gate circuits can be reduced to half compared to conventional circuits, and the phase control of the thyristor elements can be performed for only one phase. The purpose of the present invention is to simplify a phase control circuit and obtain a charging circuit for an inverter device that is inexpensive and compact.

[Means to solve the problem]

The charging circuit for an inverter device according to the present invention configures a multi-phase full-wave rectifying mixed bridge circuit with thyristor elements and diode elements, and controls the phase of only one phase of the thyristor element by a phase control circuit. The DC link capacitor is initially charged, and after the initial charging is completed, a gate signal is applied to all the thyristor elements of the multi-phase full-wave rectifying mixed bridge circuit, and the thyristor element firing is applied to the positive output terminal of the forward converter. This is an insulated connection between a power supply circuit and a phase control circuit.

[Effect]

The multiphase full-wave rectifier bridge circuit of the forward converter in this invention first charges the DC link capacitor with
In order to turn on one thyristor element, the switching element is controlled by the phase control circuit, and when charging is completed, the other two thyristor elements are turned on via the switching element, and the forward converter operates during normal operation. .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, U, V, and W are the three-phase AC power supply U, V,
AC input terminals to which each W phase is connected, ■ is a forward converter that converts three-phase AC power to DC power, and thyristor element 2-
U, 2-V, 2-W and diode element 2-X, l-Y
, 2-Z constitute a multi-phase full-wave rectifying mixed bridge circuit. 2 is a positive output terminal of the forward converter 1, 3 is a negative output terminal, 4 is a DC link capacitor connected between the positive and negative output terminals 2 and 3, and 5 is a power transistor module, etc. An inverse converter is constructed, 6 is a power supply circuit for igniting the thyristor element, 7 is a resistor for limiting the thyristor gate current, and 8 and 9 are the thyristor elements 2-U and 2-V.
, a switching element that controls the gate of l-W, 1.0
．． 11 is an insulating transformer, and 12 is a phase control circuit for the switching elements 8 and 9. Next, the operation will be explained. First, the gate signals to the thyristor elements 2-V and 2-W are cut off, and the gate signals are supplied only to the thyristor element 2-U. In this case, a voltage is applied to the thyristor element in the forward direction as shown in FIG. 2(A). During this period, the phase-to-phase voltage of three-phase AC power is the voltage y u - v seen from the ■ phase to the U phase, and the voltage V 1 seen from the W phase to the U phase.
It is known that 1-W is a positive period. Here, if the period of supplying the gate signal to the gate of the thyristor element 2-U is from the α-180° point to the α-90° point shown in FIG. 2(A), the W-phase potential of the three-phase AC power is The diode elements 2-X and 2-Y shown in FIG. 1 are reverse-biased and rendered non-conductive, forming the equivalent circuit shown in FIG. 3. Here, RA and LA concentrate and display the impedances distributed and present in the supply line when three-phase AC power is supplied. Also, as known from Figure 2, α-90
At the point of °, the output voltage of the forward converter 1 becomes the peak value of Va-ty, which is 6-1 with the maximum value of the output of the forward converter. Therefore, by supplying a gate signal as shown in FIG. 2(D) to the thyristor element 2-U of the forward converter 1 shown in FIG. Charging becomes possible up to the output voltage (Figure 2 (
C)). The solid line in FIG. 2(A), which is not shown in FIG. 2(D), indicates the voltage output by the forward converter 1 in response to a gate signal, and the solid line in FIG. 2(B) indicates the charging current to the DC link capacitor 4. in this case,
The speed of phase control of the thyristor element 2-U, that is, the speed of shifting the gate signal supply from α-180° to 90°, is:
The charging current value to the DC link capacitor 4 is changed at a speed that does not exceed a certain limit value. On the other hand, a power supply circuit 6 for igniting a thyristor element which receives AC power via an insulating transformer 10 and outputs DC power supplies the negative potential to the thyristor element 2-U in the forward converter 1. The cathode potential is 2-V, 2-W, and the positive potential is the switching element 8 and the Zyristor gate current control resistor 7.
It is connected to the thyristor element 2-U through. On the other hand, the thyristor gate current limiting resistor 7 connected to the gate 1 of the thyristor elements 2-V and 2-W is connected to the switching element 9.
It is connected via. As a result, the thyristor element 2
-U phase control is performed by making the switching element 8 conductive or non-conducting. When charging of the DC link capacitor 4 is completed, the switching element 8.9 is made conductive, and the thyristor elements 2-U, 2-V, 2 −W is a diode 2−χ,
Make it work equivalent to 2-Y and 2-Z.

【Effect of the invention】

As described below, according to the present invention, a forward converter of an inverter device is configured with a diode element and a thyristor element,
Initial charging of the DC link capacitor is phase-controlled with one thyristor element, and the thyristor element ignition power supply circuit is connected to the thyristor element cathode common part, and one for the element that performs phase control and one for other elements. Since the circuit configuration is such that power is supplied to the gates of the two groups, it is possible to obtain a small and inexpensive charging circuit for the inverter device.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a charging circuit of an inverter device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the circuit of FIG. 1,
Fig. 3 is an equivalent circuit diagram when the thyristor element 2-U of Fig. 1 is not shown in Fig. 2 and the phase is controlled in the range α-90° to 1800, and Fig. 4 is the circuit configuration of a conventional forward converter. It is a diagram. ■ is a forward converter, 2 is a positive output terminal, 3 is a negative output terminal,
4 is a DC link capacitor, 5 is an inverter, 6 is a power supply circuit for igniting the thyristor element, 8°9 is a switching element, and 12 is a phase control circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Procedural amendment (voluntary)] 2. Name of the invention: Charging circuit for inverter device 3. Person making the amendment: Relationship Patent applicant address: 2-3 Potter-chome, Maruno, Chiyoda-ku, Tokyo Name (601) Mitsubishi Denki Co., Ltd. Representative Moriya Shiki 4, Agent Postal code 105 Address
1-4-10-5 Nishi-Shinbashi, Minato-ku, Tokyo, the scope of claims is amended as shown in Column 6 of the scope of claims of the specification to be amended, contents of the amendment attached. Amended Claims: A forward converter that rectifies AC power and converts it into DC power, and a DC link capacitor and an inverse converter between the positive output terminal and the negative output terminal of the forward converter. In a charging circuit of inverter devices connected in parallel, a thyristor element and a diode element constituting the forward converter, the cathode of the thyristor element is connected to the positive output terminal of the forward converter, and the cathode of the thyristor element is connected to the negative output terminal of the forward converter. A multi-phase full-wave rectifying mixed bridge circuit to which the anode of the diode element is connected, and one in the converter for initial charging of the DC link capacitor.
thyristor elements in the forward converter, and a phase control circuit that controls the switching element so that it can continuously supply power to the gate terminals of all the thyristor elements in the forward converter after charging is completed. 1. A charging circuit for an inverter device, comprising: a power supply circuit for igniting a thyristor element that supplies electric power.

Claims (1)

[Claims] Charging of an inverter device comprising a forward converter that rectifies AC power and converts it into DC power, and a DC link capacitor and an inverter connected in parallel between the positive output terminal and negative output terminal of the forward converter. In the circuit, the forward converter includes a thyristor element and a diode element, a cathode of the thyristor element is connected to a positive output terminal of the forward converter, and an anode of the diode element is connected to a negative output terminal of the forward converter. A multi-phase full-wave rectifying mixed bridge circuit and a single circuit in the forward converter perform initial charging of the DC link capacitor.
thyristor elements in the forward converter, and after charging is completed, the phase control circuit controls the switching element so that continuous power can be supplied to the gate terminals of all the thyristor elements in the forward converter, and the DC power is supplied to the switching element. A charging circuit for an inverter device, comprising: a power supply circuit for igniting a thyristor element.