JPH02114894A - Controller for motor - Google Patents

Abstract

PURPOSE:To relax the shock of start and stoppage, and to enable regeneration by controlling the low speed of the period of odd times as large as power-supply synchronous speed and the power-supply synchronous speed by using seven bidirectional controlling elements. CONSTITUTION:The input sides of TRIACs UP, VP, WP are connected to the R phase of an AC power, the input sides of UN, VN, WN to S phase, and the input side of W to T phase; and the output sides of the TRIACs UP, UN are bonded with the U phase of a motor 9, the output sides of VP, UN with V phase, and the output sides of WP, WN, W with W phase. The TRIACs UP, VN, W or VP, UN, W are ignited separately by an output from an ignition circuit 3 and a motor is forward rotated and reverse rotated on synchronous operation, and these TRIACs are ignited in the previously determined order to run the motor on low-speed operation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control device that changes the rotational speed of an induction motor step by step, and is particularly applicable to a large lift door that requires reverse rotation and a negative torque of 1 to 100 lbs. The present invention relates to an electric motor control device suitable for a drive device.

[Conventional technology]

Conventional motor control equipment connects the motor directly to the power source using two reversible magnetic contactors, but this method poses the problem of wear and tear on the magnetic contactors. The disadvantage is that the mechanical impact is large and high speed cannot be achieved.

Furthermore, as in Japanese Utility Model Application Laid-Open No. 60-73392, it has been proposed to make the opening and closing operation contactless using a bidirectional control element or the like.

[Problem to be solved by the invention]

However, although wear and tear can be prevented in Japanese Utility Model Application Publication No. 60-73392, there are drawbacks similar to those described above in increasing speed.

That is, in order to increase the speed, it is very important to reduce the speed only when starting and stopping the electric motor. Conventionally, as a speed control device for an induction motor, a three-phase AC power source is rectified into DC, and then the speed is changed to variable frequency AC using an inverter using transistors or thyristors. For such a load, the circuit is complicated and expensive, and there are other problems such as difficulty in obtaining good characteristics for negative torque. Specifically, the dynamic braking method, in which a resistor is inserted into the DC circuit when the motor is running at negative 1-lux, has problems such as heat generation and reduced efficiency. There is a method of backing up the power to the power supply during negative torque, but as the number of main circuit arms increases, the control circuit becomes more complex, and giving the ignition timing becomes significantly more complicated, making it impossible to realize an inexpensive control device. .

An object of the present invention is to provide a control device for an electric machine that has a simple configuration and is inexpensive.

[Means to solve the problem]

The present invention provides that in a control device for a large lift door, etc., a low-speed bottom is required for a very short period of time only when starting or stopping an electric motor, and if the purpose is simply to alleviate mechanical shock, the speed control is not necessarily continuous. Focusing on the fact that certain things are not necessary, we realized motor control with an extremely simple configuration by using a bidirectional control element, which is the simplest configuration of a power circuit semiconductor element, and a microprocessor.

[Effect]

According to the present invention, seven bidirectional control elements are used as main circuit elements to perform low-speed control in which the power synchronization speed and cycle are odd multiples of the power supply synchronization speed and period.

〔Example〕

Below, an example in which the present invention is applied to a large elevating door is shown in Figs.
This will be explained with reference to FIG.

FIG. 1 shows an example of the overall configuration of a large elevating door comprising a control device 12 of the present invention, a three-phase AC motor 7, an elevating door 9, and the like. Second
The figure shows an example of a control flow of the control device of the present invention. FIG. 3 shows the relationship between the waveform output by the control device of the present invention to the three-phase AC motor and the power supply waveform.

FIG. 4 shows an example of the characteristics of a three-phase AC motor that serves as a load for the control device of the present invention.

The control device 12 of the present invention shown in FIG. 1 includes an I-Liac 1 (BR-UP-VP-WP-U
N-VN-WN-W), l-Liack 1 UP, VP
, WP input side is connected to R phase of AC power supply, UN, VN, W
The input side of N and BR.

The input side of W is connected to the S phase of the AC power supply, and the input side of W is connected to the T phase of the AC power supply.
The output sides of UP and UN are connected to the U phase of the 3-phase AC motor 7.
The output side of P and VN is connected to the ■ phase of the three-phase AC motor 7, and the
, WN, W are connected to the W phase of the 3-phase AC motor 7, and the output sides of B
The output side of R is connected to the V phase of the brake 8. 1
~The ignition circuit 3 for igniting the LIAC 1 is connected to the gate of the I/LIAC 1, and is a synchronization circuit that generates a pulse near the zero cross of the power supply R-8 in order to synchronize the ignition pulse with the power supply. 4 is connected to the ignition circuit 3.

The elevator door deceleration/stop limit switch 14 and -1-lift/lower/stop pushbutton switch 15 are connected to the input circuit 6 that receives the signal.The operation mode is determined from the state of the input circuit 6, and the operation mode is set to that mode. The microprocessor 2, which generates the matched ignition pulses, is constituted by a power supply circuit 5, which is connected to an ignition circuit 3, a synchronization circuit 4, an input circuit 6, and which generates and supplies the power for the entire control device 12.

The elevator door 9 is configured such that the rotation of the three-phase AC motor 7 is reduced by a reducer 10 that is mechanically connected to the three-phase AC motor 7.
The shirt 1-13 rotates to take up and unwind the elevating door 9, thereby raising and lowering the shirt.

The wiring breaker 11 is used to turn on and off the power to the control device 12 .

The operation of the control device 12 is as follows: When the wiring circuit breaker 1 is turned on, a power reset 1- signal is input from the power supply circuit 5 to the microprocessor 2, and the microprocessor 2 enters the power reset 1 process shown in FIG. The period of the synchronization signal from the synchronization circuit 4 is measured to identify the frequency of the power supply, and timer data and ignition pulse data for the triac 1 are set in accordance with the power supply frequency. Next, the state at the time of a synchronization signal interrupt occurs, and the deceleration/stop limit 1 to switch 14 is set at the cycle of the synchronization signal interrupt.
, the status of the rise/fall/stop switch 15 is taken in via the input circuit 6.

A new operation mode is created from the state of the deceleration/stop limit switch 14 and the raise/lower/stop switch 15. The timer built into the microprocessor 2 is set. When a timer interrupt after timer cell 1 occurs, an ignition pulse suitable for the operating mode is generated to ignite the triac 1, and a voltage is applied to the three-phase AC motor 7 to rotate it.

A time chart of the rotational speed of the three-phase AC motor 7, the voltage applied to the brake 8, the deceleration/stop limit switch 14, and the rise/fall/stop switch 15 is shown in FIG.

As shown in FIG. 5, when the ascending command is input, the three-phase AC motor 7 starts rotating at a low speed. TBR time The brake is divided by 8 and rises to the low rated speed.After the TA time, it rotates at high speed and the elevator door rises at high speed.Then, the deceleration limit for rising is 1.
- When the switch 14 is turned off, the speed is changed to low speed and regeneratively decelerated to a low speed. Next, when the TD waiting time or the stop limit switch 14 is turned off, the speed is stopped.

The operating state of the three-phase AC motor 7 will be explained with reference to FIG. While the lift door is rising, it operates in the state (3), and power is supplied to the three-phase AC motor 7 from the power supply. While descending, drive in the state of ■.
The three-phase AC motor 7 performs regenerative operation in which power is returned to the power source.

During the transition from high speed to low speed, the low speed frequency is 1.
In the case of 73, the state becomes O, and deceleration torque is generated to decelerate the vehicle. Next, an example of the waveform output by the control device 12 of the present invention will be explained with reference to FIG.

If you want to raise it at high speed, set UP-V to 1.
N-W is ignited and the voltage in phase with the power supply is applied to the 3-phase AC motor 7.
to be applied. If you want to descend at high speed, use Triac 1
VP-UN-W is ignited to apply a voltage of opposite phase to the power supply to the three-phase AC motor 7.

If you want to raise it by 1 at low speed, UP - of triac 1.
VP-WP-UN-VN-WN are fired in sequence according to pre-programmed data, and a three-phase waveform with a fundamental frequency of 1/3 of the frequency of the power supply is applied to the three-phase AC motor 7 from the R-8 voltage of the power supply. do. This voltage causes the three-phase AC motor 7 to rotate at a rotational speed that is 1/3 of the power supply frequency at a synchronous speed.

When descending at low speed, it is the same as when ascending at low speed.
By changing the firing order of the reactor 1, a reverse phase is created and applied to the three-phase AC motor 7.

[Effects of the Invention] According to the present invention, it is possible to apply voltages of several frequencies to a three-phase AC motor using seven 1-reacts, and even when a reverse load is applied to the three-phase AC motor, regeneration is possible. , the speed can be varied. In addition, by specifically driving the large lift door with the control device of the present invention, it is possible to reduce the impact applied to the lift door when starting and stopping, which makes it possible to extend the life of the lift door, and to increase the speed and impact when starting and stopping. If the values are the same, the intermediate speed can be increased, and the ascent and descent times can be shortened by 1.

In addition, in the above explanation, it was explained that control can be performed with seven main circuit elements in the case where both the power supply and motor are three-phase, but as can be easily estimated, two more main circuit elements are added,
The three phases of the power supply and the three phases of the motor can each be connected using one of the main circuit elements, and the power supplies are used alternately at low speeds to improve the balance between the phases of the power supply and the flow of the main circuit control elements. Equalization can also be achieved. In this case, equalization can be achieved by connecting the motor to the power supply through different control elements at certain time intervals not only at low speeds but also at high speeds, thereby equalizing the flow of current through the main circuit control elements.

In this case, the number of 9 arms and main circuit control elements will increase, but if the motor capacity is large or if the power supply is an uninterruptible power supply with a small short-circuit capacity, etc., phase-to-phase balance of the load has priority over the motor price. It is valid.

In the above embodiment, a triac is used as a bidirectional control element, but due to capacitance or other reasons, other unidirectional control elements connected in antiparallel, such as one
- Of course, it can also be realized using transistors, thyristors, GTOs, FETs, etc.

Further, the present invention can be applied even when the number of phases of the power supply and the motor are different.

According to the configuration of the embodiment of the present invention using a microprocessor, even in the case of the following various modified applications, the control device is almost the same, except for the type and number of main circuit control elements. This can be handled by changing the parameter table referenced by the program, which is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of the present invention, FIG. 3 is a waveform diagram, and FIG. 4 is a characteristic diagram of a three-phase AC motor. FIG. 5 is a time chart 1 for explaining the present invention in detail. 1..1-Liatsuk, 2.Microprocessor, 3
- Ignition circuit, 4 - Synchronous circuit, 5 Power supply circuit, 6 - Input circuit, 7 - 3-phase AC motor, 8... Brake, 9...
・Elevating door, 10...Reducer, 11...Wiring breaker,
13...Shaft, 14...Limit switch.

Claims (1)

[Claims] When an induction motor is driven by a one- and three-phase AC power supply, six bidirectional control elements are connected between arbitrary two phases of the AC power supply and three-phase terminals of the induction motor. At the same time, a seventh bidirectional control element is connected between the remaining one phase of the AC power source and any one phase of the induction motor, and when the induction motor is operated at high speed, the seventh bidirectional control element is connected between the remaining one phase of the AC power source and one arbitrary phase of the induction motor. A control device for a motor, characterized in that a phase voltage is applied to the induction motor to control the phase of the six bidirectional control elements when operating at low speed. 2. A plurality of bidirectional control elements are connected between the AC power supply and the induction motor, and when the induction motor is started and stopped, an odd-numbered voltage is applied to the induction motor among the voltages for each half cycle of the AC power supply voltage. A control device for an electric motor, characterized in that the motor is operated at a low speed by controlling the voltage applied thereto. 3. A plurality of bidirectional control elements are provided between the AC power supply and the induction motor, and a microprocessor is provided to output firing pulses to these bidirectional control elements, and the number of arms of the bidirectional control elements and the speed control time are determined. 1. A control device for an electric motor, characterized in that a change in a target schedule can be handled by changing a parameter table referenced by a program of the microprocessor. 4. According to claim 3, a synchronization detection circuit is provided for a representative phase of the AC power supply, and the synchronization timing of other phases is calculated and controlled within the microprocessor. Electric motor control device.