JPS63161886A - Consumption circuit for regenerative energy of inverter device - Google Patents

Abstract

PURPOSE:To prevent an abnormal temperature rise and burning by incorporating a temperature sensor into a brake resistor, detecting the temperature rise of the brake resistor and interrupting currents fed from a rectifier. CONSTITUTION:AC power 1 is converted into DC power by a rectifier 1 and a smoothing capacitor 6, and an induction motor 2 is operated through an inverter 3 by DC power. The inverter device makes a brake resistor 4 consume regenerative energy by back electromotive force. A temperature sensor 1 being incorporated into the brake resistor 4 and detecting the temperature of the brake resistor, a second electromagnetic contactor 15, excitation of which is released by a driver circuit 12 receiving a detecting signal from the temperature sensor 14, and a contact 16 for the contactor 15 are added at that time. Consequently, when a transistor 5 for controlling the brake resistor continues a conductive state, the temperature sensor 14 is broken and the excitation of the second electromagnetic contactor 15 is released through the driver circuit 12 when the temperature of the resistor 4 rises and reaches a fixed temperature. Accordingly, the contact 16 is broken, and currents to the brake resistor 4 are interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inverter device C that drives an induction motor at a desired frequency.

[Conventional technology]

FIG. 5 is a diagram showing a regenerative energy consumption circuit due to brake resistance in a conventional inverter device, for example.
(1) is a rectifier that converts AC w, # into a DC 'l source, (2) is an induction motor, (3) is an inverter that drives the induction electric stop (2), and (4) is an inverter ( 3) Induction when the drive is stopped! Brake resistance that consumes regenerative energy due to back electromotive force generated from motive (2), (5
) is the brake resistance control transistor that controls the brake resistance (4), (6) is the smoothing capacitor connected to the output side of the rectifier (]), and (7) is the inrush current to the smoothing capacitor (6). (8) is a control circuit that controls a brake resistance control transistor; (9) is a control circuit that controls a brake resistance control transistor;
) is a pressure detection circuit that detects the f pressure across the smoothing capacitor (6), $-# of C1 (l is the electromagnetic contactor coil Ql connected in parallel with the inrush downstream suppression resistor (7)), (2) is the drive v1 circuit that drives the magnetic contactor coil αυ.

Next, let's talk about the action. When braking is applied from the inverter (3), the back electromotive force generated from the induction wave (2) becomes regenerative energy and returns to the TiT'Q451, which charges the smoothing capacitor (6). 7. The W pressure at both ends of this increases. This voltage is detected by the internal pressure detection circuit (9), and when this detected value becomes constant and rises above '', the control circuit (8) controls the brake resistance control transistor (
5) is made conductive and the above regenerated energy is transferred to the brake resistance (
4) Make them stand around as if they were consuming it.

[The problem that the invention seeks to solve, ()

The circuit for consuming regenerative energy due to the brake resistance of the conventional inverter device is configured as described above. Therefore, due to failure of the brake resistance control transistor (5) or failure of the limiting circuit V-(8), etc. , if the collector and emitter of the brake resistance control transistor (5) continue to be electrically connected, connect the rectifier (1) to the brake resistance (6).
) The current from t1'R flows, causing problems such as abnormal temperature rise and burnout of the brake resistor.

This invention was made to solve the above-mentioned problems, and it is an object of the present invention to protect the brake resistor from burning out even if the brake resistor control transistor continues to be in the conductive state (2).

[Means for solving problems]

The inverter device according to the present invention has a built-in temperature sensor for detecting moisture, and the outlet for dissipating the regenerative energy by the brake resistor of the inverter device has a built-in temperature sensor that detects moisture, and when the temperature of the brake resistor reaches the set temperature of the temperature sensor. , which cuts off the current supplied to the brake resistor from the DC wave.

[for use]

In this invention, the friction sensor detects the temperature of the brake resistor and cuts off the flow supplied to the brake resistor.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, the same reference numerals as in FIG. 5, in which the conventional example is shown by h, indicate the same parts, and the explanation will be omitted. Referring to Figure 1, αth is the temperature 7I of the brake resistor (4) built into the brake resistor (4).
=Temperature sensor to be detected, αG is the drive circuit that receives the detection signal of the temperature sensor←2, the second electromagnetic contactor is deenergized by 2, αG is the contact of the electromagnetic contactor (e).

Next, the operation will be explained. The operation of consuming the regenerated energy by the brake resistor (4) is the same as the conventional example, so the explanation will be omitted.If the brake resistor control transistor (5) connects the conductive part for some reason. I will explain about it. When the brake resistance control transistor (5) continues to be conductive afe, the thickness of the brake resistance (4) increases due to the current supplied from the rectifier (1). When the temperature of the brake resistor (4) reaches a predetermined temperature, the temperature sensor f141 operates to open, and the 8 force is detected by the drive circuit @1, and the excitation of the second contactor 0υ is released. α0, which is connected to the second electromagnetic contactor α9 connected to the output voltage 1 of the rectifier (1), is opened to cut off the rectification to the brake resistor (4). As a result, the brake resistance (4
) temperature rise will overturn the suppression force from 1 burnout.

In the upper embodiment, the contact and the contact of the second electromagnetic contactor αG are
υ is connected to the output side of the rectifier (1), but it can also be connected to the input side of the rectifier (1) as shown in Figures 2 or 3, or as shown in Figure 4. As shown in the diagram, the brake resistor (4) and the brake resistor control transistor (5) are
Needless to say, the same effect as in the above embodiment can be obtained even if the filter is connected in series to fi.

In the above embodiment, a temperature sensor with a mechanical contact was used, but even if this is converted into a temperature signal using a thermistor pair and then input to the drive circuit (9), the above implementation will still work. It has the same effect as the example.

Furthermore, in the above embodiment, the brake resistor (4) is
) The contact ζαe of the second 7-magnetic contactor α9 was used to cut off the r current supplied from the transistor or GTO (gate turn-off transistor). It goes without saying that even if the control is performed using the detection signal !, the same effect as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, a temperature sensor is built into the brake resistor, and the temperature sensor is installed in the brake resistor. Since the current supplied from the rectifier is cut off by detecting the rise in AK, it is effective to prevent burnout due to abnormal temperature rise of the brake resistor.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a regenerative energy consumption circuit due to the brake resistance of an inverter device according to an embodiment of the present invention, and FIGS. 2 to 4 are diagrams showing the downstream side of the pond according to the present invention. FIG. 5 is a diagram showing a circuit consuming regenerative energy due to brake resistance of a conventional inverter device. In the figure, (1) is a rectifier, (2) is an induction motor, (
4) is the brake resistance, α pull temperature sensor, and O! 19 is a second electromagnetic contactor, and Q6 is a contact point of the second electromagnetic contactor. In addition, the same numbers in the figures indicate the same or Japanese parts. Representative Saito Masuo Oiwa Diagram 1 Procedural Amendment (Voluntary) Showa Year, Month, Day 2, Name of the invention Regenerative energy consumption circuit of an inverter device 3, Relationship with the person making the amendment Case Moriya Shiki, representative of the patent applicant 4, agent

Claims (1)

[Claims] In an inverter device that returns back electromotive force generated during braking of an induction motor to a DC power source as regenerative energy and consumes it in a brake resistor connected in parallel to the DC power source, the temperature of the brake resistor is detected by the brake resistor. A regenerative energy consumption circuit for an inverter device, characterized in that the regenerative energy consumption circuit includes a built-in temperature sensor, and cuts off the current supplied from the DC power source to the brake resistor when the temperature of the brake resistor reaches a set temperature of the temperature sensor. .