JPH0265694A - Ac spindle motor driver circuit - Google Patents

Abstract

PURPOSE:To regeneratively control in a small-sized circuit by employing a voltage drive type transistor in a conversion semiconductor bridge circuit for converting or inverting a commercial power source to drive a spindle motor, and driving it with an optical/voltage converter. CONSTITUTION:3-phase AC voltages RNT are 3-phase full-wave rectified by voltage drive type transistor MBT elements through a switch MCC and a reactor ACR. Then, 3-phase VVVF AC voltages (u)-(w) are generated by MBT elements Q11-Q16 to drive a spindle motor M. When the motor M is decelerated, a power is regenerated. The gates of the MBTs are controlled by photoelectric converters 1, 2. A light emitting element L1 generates a light by the rise of an input signal IN through an inverter 4, and the MBTQ is turned ON by a photodetector S1. A light emitting element L2 generates a light by the fall of the signal IN through a buffer 3, and the MBTQ is turned OFF by a photodetector S2. Thus, the number of components is reduced to facilitate the control of a large current and the control of a high speed rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an AC spindle motor drive circuit that performs power running/regeneration control of an AC spindle motor.

(Prior Art) An AC spindle motor (AC motor) that drives a machine tool repeatedly accelerates or decelerates depending on the characteristics of the load it drives, and its load torque may change in a positive or negative direction.

There are various control means for processing rotational energy during deceleration, but a drive circuit that can perform regenerative control of converting rotational energy into electric power and transmitting it to a power source is widely used as an electric braking means.

Figure 3 shows a circuit diagram showing an example of this type of drive circuit. When driving an AC motor, a three-phase power supply is converted to DC by a DI-PG connected to a bridge circuit, and T r
11 to T r 1t3, the inverter circuit supplies the AC power as alternating current power to the AC motor. Further, during regeneration control, power from the AC motor is rectified by D11 to 01G, and then converted to AC power by a semiconductor bridge circuit of Tr1 to Tr6 to perform power regeneration.

And Tr 11 to Tr 16 filled with bridge contact
Power transistors with large current capacities are used in inverter circuits and the like, and a drive circuit as shown in FIG. 4, for example, is used in the base circuit of these power transistors.

(Problem to be Solved by the Invention) In a drive circuit using power transistors as described above, a drive circuit as shown in Fig. 4 is required at the base of each transistor connected to the bridge circuit. This drive heat generation requires electrical components such as current amplification and voltage amplification transistors, as well as diodes, capacitors, and resistors, so the number of these components is large and the printed circuit board to be mounted is large. This has disadvantages in that it requires space and also requires a power source for this drive circuit.

The present invention was made in view of such problems,
An object of the present invention is to provide a drive circuit for an AC spindle motor that reduces the number of components in the drive circuit that controls the AC spindle motor to carry/regenerate.

(Means for Solving the Problems) According to the present invention, after rectifying AC power, the inverter of the semiconductor bridge circuit controls the AC frequency and voltage to drive the AC spindle motor, and at the same time decelerates the AC spindle motor. In an AC spindle motor drive circuit that sometimes rectifies and smoothes the induced electromotive force and converts it into AC power using a semiconductor bridge circuit to regenerate power, a voltage-driven transistor is adopted as the semiconductor element of the semiconductor bridge circuit, and the transistor An AC spindle motor drive circuit using a photovoltage conversion element in the drive circuit is provided.

(Function) In the present invention, a voltage-driven transistor is used as the semiconductor element of the semiconductor bridge circuit, and a photovoltage conversion element is used in the drive circuit. Therefore, a power source in the previous stage is not required, and the number of components in the drive circuit is reduced. This has the effect of reducing the space for mounted components.

(Example) Next, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a drive circuit diagram showing one embodiment of the present invention, and FIG. 2 is a circuit diagram of the main part of the drive circuit using this embodiment.

In FIG. 2, MCC is a circuit breaker and ACR is a reactor, which are connected to a bridge circuit constituted by semiconductor elements Ql#Q6 each having diodes D1 to D6 in parallel. Note that the semiconductor element Q1%Q6 uses a voltage-driven transistor (MBT), which is a transistor with a very large input impedance like an FET (field effect transistor), and can be operated by simply applying a predetermined voltage to the base as an input. Large current can be controlled.

When the AC spindle motor (AC motor) M is driven in parallel, the power from the three-phase AC power supplies R, S, and T is ol-w.
[)6 to operate the rectifier and convert it to DC, and when regenerating the power of the AC converter M, it is turned on/off by Q, ~Q6.
This serves as a current-carrying circuit that regenerates the off-controlled output to the power source.

The semiconductor element Qll"""QIE consists of an MBT and is an inverter circuit that converts the DC power from the smoothing capacitor C2 into AC power when the AC motor M is driven in reverse direction, and is a controller manually operated by the drive circuit (DR) described later. R.C.
According to the signal, the voltage and frequency of the AC output are controlled *J, and the rotation speed and torque of the AC motor M are controlled. In addition, as a flyback diode, Ql
DIl connected in parallel to each of l"'QIEi
~D16 rectifies the 8 electromotive force from the AC motor M during deceleration and transmits the rectified power to the smoothing capacitor C2.

Resistor R1 and diode Din are smoothing capacitor C2
and a bridge circuit for on/off control of Ql to Q5 (Dt
-06 rectifier circuit) and diode D. The direction of conduction is Q from the rectifier circuit of DI'''DEi when driving
It is connected to supply current to the inverter circuits ll to Q16.

Moreover, CD is a current detector, and each detected current signal is transmitted to the controller RC.

Next, FIG. 1 shows the semiconductor element Ql --Q shown in FIG.
6, Ql 1-wQIEi MBT drive circuit is shown, 1 and 2 are photovoltage conversion elements, which have a power generation element consisting of a light emitting element and a solar cell element, and generate electricity using the light energy of the light emitting element when energized. The element generates electricity and outputs a predetermined voltage. Then, the light emitting elements 1 and 1 are connected from the power supply + side through the resistor R2 and connected to the signal input IN through the buffer 13, and the light emitting element L1 is connected to the power supply + side with the resistor R3 and to the signal input IN. Inverter 4 is connected. In addition, the output of the power generating elements s,, s2 is transmitted to the MB via an integrating circuit having a time constant due to R and C.
It is supplied to the Q input of the T element.

Next, the operation of this embodiment configured as described above will be explained. In Fig. 1, when the pulse wave shown in the figure is applied to input No. 13 IN, at the rising edge of the pulse wave, a current flows from the power supply + side to the light emitting element L1 through the buffer 3 and emits light, and this light emission generates electricity. The voltage from the light-emitting element LL is applied to the input voltage Q via the integrating circuits R and C, and the MBT with high input impedance is turned on, causing a collector current to flow.

Next, when the manually generated pulse wave falls, a current flows through the inverter 4 to the light emitting element L2, and the voltage from the power generating element S2, which has a different polarity during power generation, is input to the Q through the integrating circuits R and C. is applied to Therefore, the MBT is turned off and the collector current is cut off. and,
By changing the values of C and R of the integrating circuit and setting the time constant, the on/off time of Q can be adjusted.

In this way, in FIG. 2, the control signal from the controller RC is transmitted through the respective drive circuits to Qll to Q1.
By joining the inverter circuit of 6 and the bridge circuit of 91 to 0, the MBT of each semiconductor element Q is
The input is controlled by the voltage of the power generation element of the photovoltage conversion element, and predetermined row drive control and power regeneration control are performed.

Although the present invention has been described above with reference to the above-mentioned embodiments, various modifications and applications are possible within the scope of the gist of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) According to the present invention, a voltage-driven transistor is employed as the semiconductor element constituting the semiconductor bridge circuit, and a photovoltage conversion element is used as the drive circuit. It is unnecessary and has the advantage of reducing the number of parts, which reduces the size of the printed circuit board to be mounted.Also, voltage-driven transistors have fast switching speeds, making it easy to control high-speed rotation, and the reduced number of parts also improves reliability. It also has the effect of improving.

[Brief explanation of the drawing]

FIG. 1 is a drive circuit diagram showing one embodiment of the present invention, and FIG.
The figure is a circuit diagram of the main part of the drive circuit using this embodiment.
The figure is a circuit diagram of a conventional drive circuit, and FIG. 4 is a circuit diagram of an example of a conventional drive circuit. 1.2... Photovoltage conversion element, 3... Buffer, 4...
...Inverter, Q...Voltage driven transistor (M
BT). Patent Applicant: Representative of FANUC Co., Ltd., Patent Attorney: Mitsune Tsuji, Mitsune Fusho (spontaneous), Director General of the Japan Patent Office, October 1988, Yoshi 1) Takeshi Moon■, Indication of the case, 1988 Patent Application No. 218482 2 , Name of the invention AC spindle motor drive circuit 3, Relationship with the person making the amendment Case Patent applicant 5th (1) "Buffer 3" in the first line of page 8 of the specification is corrected to "inverter 4." (2) "Inverter 4" on page 8, line 8 of the specification is corrected to "buffer 3." Figure 1 of the drawing is corrected as shown in the attached sheet. Name: FANUC Co., Ltd. Inaba Seiuemon Representative: Seiemon Inaba 4, Agent: 6゜7゜Column 1 of Detailed Description of the Invention of the Specification Subject to Amendment, Contents of Amendment and Drawings

Claims (1)

[Claims] After rectifying the AC power, the inverter of the semiconductor bridge circuit controls the AC frequency and voltage to drive the AC spindle motor, and when the AC spindle motor is decelerated, the induced electromotive force is rectified and smoothed, and the semiconductor bridge circuit converts the AC power into AC power. In the AC spindle motor drive circuit that performs power regeneration by converting the power into
An AC spindle motor drive circuit characterized in that a photovoltage conversion element is used in the drive circuit of the transistor.