JPS60226794A - Secondary chopper controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a secondary chopper device which is a speed control device for a wound induction motor.

[Technical background of the invention and its problems]

Conventionally, a secondary chopper device, as shown in FIG. 1, includes a wound induction motor 2, a forward converter 3 that converts the secondary power into DC, and a DC circuit that converts the secondary power into DC from 200Hz to 1000H.
It is composed of a tip 7 that is repeatedly short-circuited at a high speed of z, a secondary resistor 6, a capacitor 5 for absorbing tip surge, and a diode 4.

Note that the chopper 7 is configured using a thyristor, a power transistor, a gate turn-off thyristor (hereinafter referred to as GTO), etc. as a main switching element.

This device repeatedly short-circuits the secondary resistor 6 connected to the secondary side of the induction motor 2 using the chopper 7, and the effective value of the resistance value of the secondary resistor 6 as seen from the induction motor 2 This reduces the resistance and brings about the same effect as secondary resistance control.

However, the secondary resistor 6 or the capacitor 5 is always applied with a DC voltage ec (v) that changes depending on the operation of the chopper 7 shown in FIG. Therefore, the overall efficiency of the secondary chopper device was lower than that of a Serbius device, etc., which has almost the same secondary resistance control as the secondary resistor 6 consumes the energy. FIG. 4 shows the relationship between the average voltage value FfJv) of the DC voltage ecCv and the speed in the case of a dual torque load such as a pump. In FIG. 4, H indicates the speed control range and N indicates the synchronous speed.

[Purpose of the invention]

An object of the present invention is to recover the power consumed by the secondary resistor to the power supply, thereby improving the overall efficiency.

[Summary of the invention]

The present invention includes a wound induction motor, a rectifier that converts its secondary power into direct current, a chopper device that short-circuits the direct current circuit, and a two-way motor connected between the rectifier and the chopper device.
In a secondary chopper control device constituted by a secondary resistor, the secondary power converted to direct current of the wound induction motor consumed by the secondary resistor during chopper operation is transferred through a static inverter. This is a secondary chopper control device that is characterized by returning power to the power source.

[Embodiments of the invention]

Next, examples of the present invention will be described. FIG.
a forward converter 3 that converts the three-phase AC voltage induced in the DC voltage into a DC voltage; a chopper 7 connected to short-circuit the positive terminal 3a and the negative terminal 3b on the DC output side of the forward converter 3; and a series circuit of a diode 4 and a capacitor 5 connected in parallel.

In a secondary chopper control device consisting of a secondary resistor 6 connected in parallel to a capacitor 5, a switch 8 connected in series to the secondary resistor 6 and a capacitor 5d are connected in parallel to each other. A motor 2 comprising an inverter 9 that converts the inter-terminal voltage into a three-phase AC voltage, and a transformer 10 that transforms the three-phase AC voltage output from the inverter 9 into the primary voltage of the induction motor 2. The chopper control device is shown below.

As shown in FIG. 3, a switch 8 is connected in series with the secondary resistor 6, an inverter 9 is provided in parallel with the capacitor 5 for inverting direct current to alternating current, and the alternating current output is connected to the power source through a transformer 10. It is something to do.

The switch 8 disconnects the secondary resistor 6 from the circuit during chopper operation, and the DC power conventionally consumed by the secondary resistor 6 is regenerated into a power source by the inverter 9. It is.

At this time, since the output voltage of the inverter 9 is different from the power supply voltage, a transformer 10 is required to match the voltages.

〔Effect of the invention〕

Since the electric power of Since only DC power is used to charge the capacitor, this problem is resolved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional secondary chopper device, FIG. 2 is an explanatory diagram of the operation of FIG. 1, FIG. 3 is a configuration diagram of a secondary chopper device showing an embodiment of the present invention, and FIG. 4 is an explanatory diagram of the action of FIG. 3. DESCRIPTION OF SYMBOLS 1... Switch, 2... Induction motor 3... Forward converter, 4... Diode 5... Capacitor, 6...
...Secondary resistor 7...Chopper, 8...Switch 9...Inverter, 10...Transformer agent Patent attorney Noriyuki Chika (and 1 other person) Figure 1 C 2 Figure 1'r Figure 3 Figure 4

Claims (1)

[Claims] A forward converter that is connected to the secondary winding of a wound induction motor and converts the three-phase AC voltage induced in the secondary winding into a DC voltage, and a positive terminal and a negative terminal on the DC output side of this forward converter. A secondary chopper control device comprising a chopper circuit connected to short-circuit terminals, a series circuit of a diode and a capacitor connected in parallel to this chopper circuit, and a secondary resistor connected in parallel to the capacitor. A switch connected in series to the secondary resistor, an inverter connected in parallel to the capacitor and converting the voltage across the terminals of the capacitor into a three-phase AC voltage, and an output of the inverter. and a transformer for converting a three-phase AC voltage into a primary voltage of the wound induction motor.