JPS6231390A - Controller of motor - Google Patents

Abstract

PURPOSE:To control to drive a DC motor under AC variable voltage variable frequency (VVVF) control by connecting the field of the motor with the AC output unit of the VVVF control, and chopper-controlling the AC output unit by a calculation controller. CONSTITUTION:The armature of 5 of a DC motor is connected with U-shaped and V-phase of an i nverter 4, and the field 6 of a DC motor is connected with W-phase and a cathode side ($). A current flowing to the field 6 of the motor is substantially constantly controlled on the basis of a command of a calculation controller 7 by a transistor 4c of the W-phase circuit of the inverter 4, and a current flowing to the armature 5 is chopper-controlled on the basis of the command of the controller 7 by transistors 4a, 4b, 4d, 4e of the U- and V-phasem circuits of the inverter 4. Thus, the motor can be controlled to be driven under VVVF control, and even if the motor is converted to an AC motor by the alteration of the motor, it can be processed as it is.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control device for a DC motor, particularly when the control configuration or type of motor was later updated to AC variable voltage/Tq variable frequency a (hereinafter referred to as VVVF) control. The present invention relates to a control device for an electric motor that can easily handle various situations.

[Conventional technology]

Conventionally, as a control device for high-speed elevators, the Ward-Leonard system uses a separately excited DC motor as the hoisting motor and an electric generator a (hereinafter referred to as N-G) as the power source to drive the DC motor, as shown in Fig. 3. has been used. Thereafter, as thyristor application technology progressed, thyristor Leonard control using a thyristor instead of Ni-G became mainstream for a long time.

However, in recent years, with the development of microprocessors and power transistors that can control large amounts of power, a VVVF control system using an AC induction motor instead of a DC motor has become mainstream. This improves the power factor with VVVF control, reduces the capacity of the power transformer, and reduces loss noise in the power line and converter due to the smaller input current. This is because electric motors have advantages such as requiring no maintenance. For this reason, the factory production line has been switched from the thyristor Leonard control system to the VVVF control system.

However, especially in the case of elevators, they are usually modernized (updated) after about 20 years.

At this time, the main hoisting motor is often used as is with only minor modifications for various reasons. Therefore, N-
G is updated, but of course there is a strong demand for a rotating machine like G to be stationary, and since the hoisting machine is a DC machine, a thyristor Leonard device is manufactured to make it stationary. As mentioned above, it is not standard for factory production lines, so it would be expensive to make a new one.

Furthermore, in the case of modernization, the hoisting machine and its control device may not be replaced all at once, but parts of them may be replaced one after another. This is due to the difference in the service life of each piece of equipment, and since the hoisting machine usually has a longer lifespan, the hoisting machine and its control equipment are first updated, and then after a few years have elapsed, the hoisting machine is replaced. - Machines may be updated. In this case, if you first replace the M-G and its control device with a thyristor Leonard control for DC hoist drive, but then replace the hoist with a cheap AC hoist a few years later, the control device also changes. This had the disadvantage that the thyristor Leonard control had to be replaced with VVVF control, making it expensive.

[Problem that the invention seeks to solve]

The present invention was made in view of the above points, and uses a VVVF control device currently produced as standard in factories to drive a DC motor, and even when replaced with an AC motor several years later, the VVVF control device is used to drive a DC motor.
An object of the present invention is to obtain a control device for an electric motor that can use a VF control device as is.

[Means for solving problems]

The electric motor control device according to the present invention connects the field of the DC motor to the AC output part of the VVVF control part, performs chopper control on the AC output part based on the calculation processing operation of the calculation control part, and performs chopper control on the AC output part based on the calculation processing operation of the calculation control part. This configuration drives a DC motor.

[Effect]

The AC output section of the VVVF control section in this invention performs chopper control based on the arithmetic processing operation of the arithmetic control section, and can drive various devices simply by inputting the data of the arithmetic processing operation of the arithmetic control section. Control.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows an overall circuit block diagram of the motor control device according to this embodiment. lla) to (llf) and the opposite thyristor (12a
) to (12f) are turned on and converted into DC, (2) is a smoothing capacitor that smoothes the DC converted by converter (1), (3) is a DC reactor, and (4) is The above converter (1) and smoothing capacitor (
The direct current smoothed in step 3) is formed by U-phase, ■-phase, and W-phase circuits (4a) to (4f) each formed by a diode and a transistor connected in antiparallel to the diode. An inverter that converts AC into the required variable voltage/variable frequency by the on/off operation of transistors, (5) is a DC motor connected to the U phase (U) and V phase (V) of the inverter (4). (6) is the field of the DC motor connected to the W phase (W) of the inverter (4) and the negative pole side (-) of the converter (1), and (7) is the positive field of the converter (1). side and reverse thyristor (lla)
～(Iff), (12a)～(12F) and also controls the U-phase and ■-phase circuits (4a), (4b), (4d), (4e) c7)
) An arithmetic control unit that controls on/off of the transistor and controls the operation of the DC motor; (8) is a three-phase AC power supply;

Now, in normal VVVF control, U-phase (U), V-phase (V), W-phase (W) and E-phase AC motors connected to the neutral point of the transistor are controlled by PWM (pulse width modulation) control. However, in this invention, the U phase (U)
, The armature (5) of the DC motor is in the V phase (V), and the field (6) of the DC motor is in the W phase (W) and negative pole side (-).
are connected respectively, and the voltage across the smoothing capacitor (2) is as follows: thyristor (lla) ~ (llf), (12
a) to (12F), and the transistor of the W-sum circuit (4c) of the inverter (4) keeps the current flowing in the field of the DC motor almost constant based on the command from the arithmetic control unit (7). The transistors of the U and V phase circuits (4a), (4b), (4d), and (4e) of the inverter (4) control the current flowing through the armature (5) to the arithmetic control unit (7).
) is controlled by chopper control based on commands.

The arithmetic control section (7) includes the converter (1) and...
The inverter (4) is controlled and a predetermined arithmetic operation is performed by a central processing unit (hereinafter referred to as CPU) (71), and the data necessary for the arithmetic operation of the CPU (71) is stored in the ROIll (72). 71) calculation result to RAM (73)
The configuration is such that chopper control is performed by storing commands based on the arithmetic operations of the CPU (71) to the converter (1) and inverter (4) through an interface (I/F) (74).

Next, the operation of the electric motor control device according to this embodiment based on the above configuration will be explained. Now from U phase (U) to ■ phase (V)
When trying to flow current to the side, the U of the inverter (4)
Phase, ■ Sum circuit (4a), (4e) (7) Each transistor becomes conductive. When the transistor of the U-phase circuit (4a) is turned off, the upstream side of the armature (5) cannot become zero instantaneously due to its internal reactance, and (U-phase (U
) → (armature (5)) → (V sum circuit (4e
) transistor) → (diode of U sum circuit (4d)) circuit. ■The same thing applies when the transistor of the sum circuit (4e) is turned off. In this way, by turning on and off the transistors of the U-phase and ■-phase circuits (4a) and (4e) at appropriate intervals, the current flowing through the armature (5) can be controlled. When reversing the direction of current, U phase, ■
The transistors of phase circuits (4b) and (4d) are used.

As mentioned above, in FIG. 1, the converter (1) is connected to the positive and reverse thyristors (lla) to (llf) and (12a).
It is constructed using ~(12F). This is because in the case of an elevator, regenerative power is generated and this is converted into a power source. However, when the regenerated power is small, it can be consumed by the resistance of the DC circuit.
At this time, the circuit becomes simple as shown in FIG. In the figure, (8a) to (9f) are diodes, (10) is a transistor for consuming regenerative power, and (11) is a resistor for consuming regenerative power.

When the elevator generates regenerative power, the regenerative power consuming transistor (10) is controlled and the regenerative power consuming resistor (10) is controlled.
11).

When the regenerative power is small, it is possible to consume it in the field (6) of the DC motor, and in this case, the regenerative power consumption transistor and resistors (10) and (11) are unnecessary.

Incidentally, when the hoisting motor is replaced with an AC motor several years later, the VVVF device shown in FIG. 1 or 2 can be used as is, but since this is well known, its explanation will be omitted here.

C Effects of the Invention] Hereinafter, as shown in (1)-, the motor control device according to the present invention connects the field of the DC motor to the AC output part of the VVVF control part, and connects the AC output part to the calculation of the calculation control part. Since chopper control is performed based on the processing operation, and this chopper control is used to drive the DC motor, it is possible to perform dynamic control of the DC motor using VVVF control, and it is also possible to convert it to an AC motor by updating the motor. Even if a problem occurs, it can be handled as is, and various devices can be easily controlled without the need for a dedicated control device.

[Brief explanation of the drawing]

FIG. 1 shows an overall circuit block diagram of a motor control device according to one embodiment of the present invention, FIG. 2 shows an entire circuit block diagram of another embodiment, and FIG. 3 shows an entire circuit block diagram of a conventional device. (1) is a converter, (2) is a smoothing capacitor, (3)
is the DC reactor, (4) is the inverter, (5) is the core gear, (6) is the field, (7) is the calculation control unit, (8) is the three-phase AC power supply, (lO)
is a transistor for regenerative power consumption, and (11) is a resistor for regenerative power consumption. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A motor that converts alternating current supplied from an alternating current power source into direct current using a converter, converts this direct current into three-phase variable voltage/variable frequency alternating current using an inverter, supplies it to a motor, and controls the drive of this motor. In the control device, an armature of a DC motor is connected between two phases of the inverter, and a field of the DC motor is connected between the other one phase and the negative pole side of the inverter, and the field is connected to the inverter. A control device for an electric motor, characterized in that the inverter is subjected to chopper control based on commands from an arithmetic control unit having control data corresponding to a model of the electric motor, and drive control is performed based on the chopper control.