JPH0421437B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a braking device for a motor used in a dehydrator or the like. Conventional configuration and its problems Conventionally, this type of motor braking has been configured as shown in FIG. That is, 1 is the main winding of the motor, 2 is the auxiliary winding, 3 is the phase advancing capacitor, 4 is the intermediate tap attached to the auxiliary winding 2, and the end thereof is provided with a switching terminal 6 to which a diode 5 is connected. .
7 is an AC power source connected to one terminal of the motor, and 8 is an AC power source connected to the other terminal of the motor.A switch 9 allows the AC power source 8 to be connected to the switching terminal 6 or the terminal 7. In the above configuration, when the motor is operated, the switch 9 is connected to the terminal 7, and the AC power source 8 is directly applied to the motor. Also, when braking the motor, by connecting the switch 9 to the switching terminal 6 and applying a half wave from the diode 5 to a part of the main winding 1 and the auxiliary winding 2,
It applied the brakes by converting the kinetic energy of the motor's rotor into electrical energy. However, with this configuration, the effectiveness of the brake was slow, and it took a considerable amount of time to completely stop the rotation of the motor. OBJECTS OF THE INVENTION The present invention was made to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a motor braking device that has a strong braking force and can quickly stop the rotation of the motor. Structure of the Invention In order to achieve the above object, the present invention provides a first three-terminal control element connected to a main winding of a motor, a second three-terminal control element connected to an auxiliary winding, and a second three-terminal control element connected to a main winding of a motor. , a switching circuit that supplies a signal to both or either gate terminal of the second three-terminal control element in synchronization with the zero volt cross point of the AC power source once every two times, and a predetermined period of time from the start of braking; a delay device that turns off the two three-terminal control elements, and the switching circuit supplies the signal to the gate terminal of the three-terminal control element after a predetermined time from the start of braking, and switches both three-terminal control elements off during braking. stopping the braking signal to the gate terminal to either one of the terminal control elements;
It brakes the motor. DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In FIG. 2, 11 is an AC power source, 12 is a first three-terminal control element connected to the main winding 13 of the motor, and 14 is a second three-terminal control element connected to the auxiliary winding 15 of the motor.
The three-terminal control element 16 is a phase advancing capacitor. 17 is a microcomputer, which includes a ZVS measuring section 18, a delay device 19, an arithmetic processing section 20,
It has switching circuits 21 and 22.
The ZVS measurement unit 18 measures a signal (hereinafter referred to as ZVS) synchronized with the zero volt cross point of the AC power source. The arithmetic processing section 20 performs arithmetic processing, which will be described later, based on the output of the ZVS measurement section 18, that is, the number of ZVS, and controls the subsequent switching circuits 21 and 22. The delay device 19 operates in the arithmetic processing unit 2 for a predetermined period of time from the start of braking.
0 to the switching circuits 21, 22 such that the outputs of the switching circuits 21, 22 are at the L _O level. The output terminal of the switching circuit 21 is connected via a resistor 23 to the base of a transistor 24 having an emitter grounding type, and the collector of this transistor 24 is connected to the resistor 2
5 to the gate of the first three-terminal control element 12. Note that the base of the transistor 24 is connected to a constant voltage source 27 via resistors 23 and 26. Similarly, the output terminal of the switching circuit 22 is connected via a resistor 28 to the base of a transistor 29 whose emitter is grounded, and the collector of this transistor 29 is connected to the second three-terminal control element 14 via a resistor 30. connected to the gate. Note that the base of the transistor 29 is connected to the resistor 2.
It is connected to a constant voltage source 32 via 8 and 31. Further, 33 and 34 each indicate a switching circuit. To explain the operation in the above configuration, when the motor is operated, the output terminal of the switching circuit 21 becomes Hi level, the transistor 24 is turned on, a gate signal is input to the gate of the first three-terminal control element 12, and the first The three-terminal control element 12 becomes conductive, and the main winding 13 is energized. On the other hand, the output terminal of the switching circuit 22 is at L _O level,
The transistor 29 is turned off, no gate signal is input to the gate of the second three-terminal control element 14, the second three-terminal control element 14 is non-conductive, and the auxiliary winding 15 is not energized. In this way, the main winding 13
By energizing the auxiliary winding 15 and not energizing the auxiliary winding 15, the motor rotates in a normal state. Next, the case of stopping the motor will be explained with reference to FIG. 3. When the motor stop signal is input to the arithmetic processing unit 20, the output of the delay device is input, and a signal is sent to each switching circuit 21 so that the output terminals of the switching circuits 21 and 22 are at the L _O level for a predetermined period of time. ,2
Output to 2. This switching circuit 21, 22
Since the output terminal of is at L _O level, transistors 24 and 29 are turned off, and the first three-terminal control element 1
2 and the second three-terminal control element 14 become non-conductive, and the main winding 13 and the auxiliary winding 15 are not energized. When the delay device 19 interrupts the current supply to the main winding 13 and the auxiliary winding 15 for a predetermined period of time, in step 35, the number A of ZVS is
Set to . Next, in step 36, it is determined whether or not ZVS has been input. If ZVS has been input, the number A of ZVS is set to 1 in step 37. Thereafter, the number A of ZVS is increased by one in the same way. Next, step
38 to determine whether the number A of ZVS is an even number,
If the number A is an even number, power to the main winding 13 and the auxiliary winding 15 is cut off. That is, the output terminals of the switching circuits 21 and 22 are set to the L _O level.
If the number A is a parsimonious number, in the next step 39, the number A
is larger than an arbitrary set number X.
When the number A of ZVS is smaller than the error constant X, that is, in the initial stage, the output terminals of the switching circuits 21 and 22 are set to Hi level, and the main winding 13 and the auxiliary winding 15 are energized. After that, when the number A becomes larger than the set number X, the output terminal of the switching circuit 21 is switched to L _O
At the same time, the output terminal of the switching circuit 22 is set to Hi level and the auxiliary winding 15 is energized. In the above description of the operation, the reason why the delay device 19 cuts off the power to the main winding 15 for a predetermined period of time after the motor stop signal is input is as follows. That is, as shown in FIG. 4, when a motor stop signal is input, a voltage 12a applied to both ends of the first three-terminal control element 12 and a voltage 12a applied to both ends of the second three-terminal control element 14 are applied. Phase difference t _O of voltage 14a
is large, and the output terminals of the switching circuits 21 and 22 are kept at the L _O level until this phase difference t _O becomes small (for a predetermined time), and both three-terminal control elements 12,
14 is turned off, and after a predetermined period of time, after the phase difference t _O becomes small, both three-terminal control elements 1 are turned off in synchronization with ZVS.
Gate signals can be input to both three-terminal control elements 12 and 14 at the same time, and the rush current flowing to both three-terminal control elements 12 and 14 can be reduced. In this way, in this embodiment, after the motor stop signal is input, the main winding 13 and the auxiliary winding 15 are de-energized for a predetermined period of time, and then once every two times of ZVS.
Braking is performed by flowing a current in one direction through the main winding 13 and the auxiliary winding 15 in synchronization with the rotation, and the rush current to both the three-terminal control elements 12 and 14 at this time can be reduced. Thereafter, in synchronization with every two times of ZVS, a unidirectional current is applied only to the auxiliary winding 15 to further perform braking. In the above embodiment, a half-wave current is passed through the main winding 13 for a predetermined time after a predetermined time after the motor stop signal is input, but the half-wave current to the main winding 13 is It may be kept running all the time, or it may not be run at all. By the way, in the case of the conventional example, the time for flowing half-wave current to the main winding 13 is 0 seconds,
Time until rotation stops in each case of 12 seconds, 16 seconds, and constant, and main winding 13 and auxiliary winding 15
The results of the temperature rise values are shown in the table below.

【table】

[Table] Note that although the switching circuits 33 and 34 are provided in the embodiment shown in FIG.
The output terminal of the switching circuit 22 and the gate of the first three-terminal control element 12 are connected through a resistor, and the output terminal of the switching circuit 22 and the gate of the second three-terminal control element 14 are similarly connected through a resistor. It's okay. Effects of the Invention As is clear from the above description, according to the present invention, the power supply to the main winding and the auxiliary winding is cut off for a predetermined period of time after the motor stop signal is input. ZVS on three-terminal control element simultaneously
Even if a gate signal synchronized once every two times is supplied, the inrush current is small and will not destroy the three-terminal control element. Also, since the braking signal to the gate terminal of the three-terminal control element is stopped halfway during braking,
It is also possible to suppress the temperature rise of the motor windings. In addition, for the three-terminal control element, once every two times of ZVS
Since a gate signal synchronized with the rotation is supplied, a half-wave current flows through the main and auxiliary windings, enabling efficient braking of the motor. The load on the terminal control element can be adjusted.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram of a conventional motor braking device, Fig. 2 is an electric circuit diagram of a motor braking device showing an embodiment of the present invention, and Fig. 3 is a flowchart of the electric circuit under control of a microcomputer. FIG. 4, which is a diagram showing the chart, is a voltage waveform diagram at both ends of the three-terminal control element of the same electric circuit. 12...First three-terminal control element, 13...Main winding, 14...Second three-terminal control element, 15...Auxiliary winding, 19...Delay device, 21, 22...
switching circuit.

Claims (1)

[Claims] 1 A first three-terminal control element connected to the main winding of the motor, a second three-terminal control element connected to the auxiliary winding, and an alternating current applied to the gate terminals of the first and second three-terminal control elements during braking. A switching circuit that supplies a signal synchronized with the zero volt cross point of the power supply every two times, and a delay device that turns off the two three-terminal control elements for a predetermined period of time from the start of braking, A switching circuit supplies the signal to the gate terminal of the three-terminal control element after a predetermined time from the start of braking, and stops supplying the signal to the gate terminal of either of the two three-terminal control elements halfway during braking. Braking device for the motor.