JPS63290179A - Inverter for motor brake - Google Patents

Abstract

PURPOSE:To improve safety, by operating a brake unit through utilization of a base block signal outputted from a microprocessor. CONSTITUTION:A motor brake 11 having a brake coil 12 is driven through an inverter 13. The inverter 13 rectifies and smoothes AC power fed from a power source 14 through a rectifier 15 and a capacitor 16 then inverts the smoothed power into DC power through a switching element 17. A control circuit therefor comprises a DC power source circuit 18, an operating circuit 19, a protection circuit 20, a microprocessor 21 and a base driver 22, and controls the element 17. The operating element 19 receives a free-run stop signal from a relay switch 24, and a base block signal is outputted from the microprocessor 21 according to the free-run stop signal. The protection circuit 20 disables the switching element 17 upon occurrence of over current. Brake unit is operated on the base block signal so as to synchronize ON/OFF timing of the output from the inverter 13 and the brake timing reliably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to an inverter device for an electric motor with a brake for driving an electric motor with a brake.

(Prior Art) ゛When driving an electric motor with a brake by an inverter, it is necessary to synchronize the actuation/release timing of the brake with the on/off of the output of the inverter device.

For example, when starting a motor, if the release of the brake is delayed when the output of the inverter is turned on, an excessive starting current will flow, and conversely, when the motor is stopped from operating state, the output of the inverter will be turned off. This is because if there is a delay in brake activation, an excessive load current will flow, and in any case, in the worst case, the overcurrent protection function will be activated and the inverter device will be tripped.

Therefore, in the past, for example, as shown in FIG. 3, an inverter device was included or a range controller was constructed. In the figure, reference numeral 1 denotes an inverter device controlled by a microprocessor, which is connected to a power source 3 via contacts 2 of an electromagnetic contactor so as to be able to drive a motor 4 as a load. The electric motor 4 has a built-in brake 5 that is activated when it is not energized, for example, and receives power from a brake power circuit 6 connected to the power source 2 through an electromagnetic contactor contact 10a. ing.

Reference numerals 7 and 7 denote coast-stop terminals provided in the inverter device 1, to which the electromagnetic contactor contact 9a is connected, and by closing the electromagnetic contactor contact 9a, the operation of the switching elements of the inverter main circuit is controlled. A base block signal is output from the microprocessor to stop the operation. The run/stop switch 8 provided in the operation circuit includes an electromagnetic contactor contact 9a provided at the free run stop terminal 7 of the inverter device 1, as well as an electromagnetic contactor coil for opening and closing the electromagnetic contactor contact 9b. 9 are connected in series. Further, an electromagnetic contactor coil 10 for opening and closing an electromagnetic contactor contact 10a connected to the brake power supply circuit 6 is connected in series to the electromagnetic contactor contact 9b.

In such a configuration, for example, when the run/stop switch 8 is opened while the electric motor 4 is in operation, the electromagnetic contactor coil 9 is cut off and the contacts 9a and 9b are opened after a slight time delay. When the contact 9a is opened, the inverter device 1 is placed in a free run stop state, and the microprocessor outputs a base block signal, and the inverter device 1 is turned off after a slight time delay. On the other hand, when the contact 9b is opened, the electromagnetic contactor coil 10 is cut off, and after a slight time delay, the contact 10a is opened, the power supply to the brake power circuit 6 is cut off, and the brake 5 is activated. As a result, the brake 5 is activated by 2 seconds from the operation of the run/stop switch 8.
The brake operates with a delay corresponding to the operation delay caused by the two electromagnetic contactors, and is supposed to prevent the brake from operating while the output of the inverter device is on.

(Problem to be Solved by the Invention) However, in the above configuration, the brake operation delay time depends on the unstable operation delay time of each electromagnetic contactor, so the brake is not activated while the output of the inverter device is on. There was still a relatively high possibility that the overcurrent protection would be activated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an inverter device for an electric motor with a brake that can optimally control the relationship between output on/off and brake activation timing and more reliably prevent abnormal situations such as falling into an overcurrent protection state. It is on offer.

[Structure of the Invention] (Means for Solving the Problems) The inverter device for an electric motor with a brake of the present invention is provided with a semiconductor switching element interposed in the energizing path to the brake coil, and when a coast stop command is output or The semiconductor switching device is characterized in that the semiconductor switching device is turned on and off based on a base block signal output from a microprocessor to stop the operation of the switching device in the inverter main circuit when various protection functions are activated. It is. - (Function) The on/off operation of the semiconductor switching element for braking is synchronized with the base block signal for stopping the operation of the switching element of the inverter main circuit.
Brake operation timing is optimized.

(Example) A first example of the present invention will be described below with reference to FIG.

11 is an electric motor with a brake, 12 is its brake coil,
13 is an inverter device. The main circuit configuration of the inverter device 13 is a general configuration in which AC power from a power source 14 is rectified by a rectifier 15, smoothed by a capacitor 16, and inversely converted into AC power by a switching cable 17. On the other hand, the control circuit configuration includes a DC power supply circuit 18 and an arithmetic circuit 19.
, a protection circuit 20, a microprocessor 21, and a pace driver 22 to control the switching cord 17. The arithmetic circuit 19 receives a free run stop signal from the relay switch 24 via a terminal 23, and based on this, a base block signal is output from the microprocessor 21 to the pace driver 22 via the amplifier 25, which causes the switching element 17 to is put into a non-operating state.

Furthermore, when the protection circuit 20 detects overcurrent, short circuit, overvoltage, undervoltage, etc., the protection circuit 20 also controls the microprocessor 2.
1 outputs a base block signal to the pace driver 22 via the amplifier 25, and the switching element 1
7 is brought into a non-operational state.

Now, 26 is an inverting amplifier, and 27 is an amplifier, both of whose input terminals are connected to the output terminal of the amplifier 25 so as to receive and obtain the base block signal. Reference numeral 28 denotes an NPN type transistor which is a semiconductor switching element provided within the inverter device 13. The collector of this transistor 28 is connected to one end of the brake coil 12 of the brake-equipped electric motor 11 via a terminal 29, and the emitter is connected to the negative output line of the DC power supply circuit 18. The other end of the brake coil 12 is connected to the positive output line of the DC power supply circuit 18 via the terminal 30, so that the transistor 28 is connected to the current-carrying path from the DC power supply circuit 18 to the brake coil 12. It is considered to be an mediated form. Further, the base of the transistor 28 is selectively connected to the output terminals of the inverting amplifier 26 and the non-inverting amplifier 27 via a changeover switch 31, so that it is possible to select whether the brake is a non-excitation type or an excitation type. It can be switched according to the

In the above configuration, when the brake is of a non-excitation type, the changeover switch 31 is switched to the inverting amplifier 26 side, and when it is an excitation type, it is switched to the non-inverting amplifier 27 side. Here, it is assumed that the changeover switch 31 is switched to the inverting amplifier 26 side as shown in FIG. 1, and the relay switch 24 is closed and a free run stop +h command is given. Then, the microprocessor
A base block signal is output from 21 to the pace driver 22 via the amplifier 25, and the pace driver 22 stops the operation of the switching element 17 and turns off the output of the inverter device 13.

At the same time, the output terminal of the inverting amplifier 26 changes to a low level and the transistor 28 turns off, so that the brake coil 12 is cut off and the brake is activated. In addition, the protection circuit 20 may be activated due to overcurrent, etc., and the microprocessor may
Also when the base block signal is output from the main circuit 21, the switching element 17 of the main circuit becomes inactive, the transistor 28 is turned off, and the brake is activated.

According to this, since the brake is actuated based on the base block signal, the on/off of the output of the inverter device 13 and the brake timing are reliably synchronized, and the timings of both can be controlled optimally. Therefore, it is possible to reliably prevent the brake from operating while the output of the inverter device 13 is on, or from turning on the output of the inverter device 13 while the brake is in the operating state. Furthermore, since the brake is automatically activated when the protection circuit 20 is activated, there is also the effect that the safety of hoists, cranes, conveyors, etc. can be further improved. Furthermore,
In particular, in this embodiment, power is supplied to the brake coil 12 from the DC power supply circuit 18 built into the inverter device 13, which eliminates the need for a dedicated separate power supply, resulting in space savings and miniaturization of the entire system. I can make it possible.

FIG. 2 shows a second embodiment of the invention. The main difference from the first embodiment is that the smoothing capacitor in the main circuit is divided into two capacitors 32 and 33, and the brake power is obtained from one capacitor 33. Since the points are similar to those in the first embodiment, the same parts are given the same reference numerals and a detailed explanation will be omitted. With this configuration, the circuit configuration of the brake power source is simplified, so there is an advantage that the number of parts of the inverter device 13 can be reduced and the inverter device 13 can be made smaller and lower in cost. - [Structure of the Invention] As described above, the present invention has a structure in which the brake device is operated using the base block signal output from the microprocessor, so the on/off of the output of the inverter device and the brake timing can be controlled. Abnormalities such as overcurrent trips caused by discrepancies in brake operation when the optimum relationship is not achieved! This has the excellent effect of being able to prevent the occurrence of the jt state.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a block diagram showing a second embodiment, and FIG. 3 is a block diagram showing a conventional example. In the drawing, 11 is an electric motor with a brake, 12 is a brake coil, 13 is an inverter device, 17 is a switching element, 2
1 is a microprocessor; 128 is a transistor (semiconductor switching element); Agent: Patent Attorney Noriyuki Chika Kendai No. 1 (2 Fig. 2 Fig. 3)

Claims (1)

[Claims] 1. A semiconductor switching element that is controlled by a microprocessor and is interposed in the energizing path to the brake coil in a device for driving a brake-equipped motor equipped with a brake that is activated in response to energization or disconnection of the brake coil. The semiconductor switching device is configured to control the semiconductor switching based on the base block signal output from the microprocessor to stop the operation of the switching elements of the inverter main circuit when the microprocessor outputs a free-run stop command or when various protection functions are activated. An inverter device for an electric motor with a brake, characterized in that an element is turned on and off.