JP2000032791A - High voltage driven brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure stabilized speed control by performing voltage control using a low DC voltage produced from a chopper circuit as a self power supply, generating a speed pulse and a speed command voltage from the low DC voltage and driving a brushless motor variably, thereby simplifying the circuitry and the wiring. SOLUTION: In a high voltage driven brushless motor, a chopper circuit 14 built in a motor 1 serves as a low voltage power supply and a high DC voltage is converted into a low DC voltage without requiring any transformer. A pre-drive circuit built in the motor 1 controls the chopper circuit 14 to detect the rotational speed of motor 1 and generate a speed pulse 12 as a self power supply. A motor drive circuit 19 is then subjected to PWM control by a speed command voltage 11 generated from a motor speed control circuit 7 depending on the speed pulse 12 and the output voltage from the chopper circuit 14 thus controlling rotation of the motor 1 appropriately. According to the arrangement, a special low voltage power supply circuit and a power supply for operating a predrive circuit can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage driven brushless motor, and more particularly to a brushless motor that directly drives a commercial power supply with a rectified high voltage.

[0002]

2. Description of the Related Art Conventional brushless motors are disclosed in
There is a technique disclosed in JP-A-2-185584. FIG. 6 is a circuit diagram showing a circuit configuration of a conventional brushless motor. In the figure, 1 is a brushless type motor driven by a DC power supply, 2 is a detector including a Hall element for detecting a magnet position of a rotor of the motor 1, 3 is an AC power supply, 4 is a rectifying circuit for rectifying AC to DC, 5 is a capacitor for smoothing the rectified DC, and 19 is a motor drive circuit for directly controlling the driving of the motor 1. 41 is a transformer for converting the AC power supply 3 to low-voltage AC, 42 is a rectifier circuit for rectifying the low-voltage AC to DC, 43 is a capacitor for smoothing the rectified DC, and 44 is a stable output voltage. A three-terminal regulator 45, which is a control IC functioning as a pre-drive circuit, usually operates at a low voltage of 30 V or less. The motor drive circuit 19 is driven by the control IC 45. In a conventional brushless motor having the above configuration, AC100V or AC200V
Is converted into a direct current and applied to the motor drive circuit 19, and the drive of the motor drive circuit 19 is appropriately controlled by a control IC 45 operated by a low-voltage DC power supply, thereby controlling the rotation of the motor 1 at a variable speed. are doing. The control of the number of rotations of the motor 1 is performed by a speed command or the like from outside the control IC 45.

[0003]

In the conventional brushless motor as described above, a low-voltage power supply for the control IC 45,
2V or 24V is required, and a special circuit using the transformer 41 is required to generate this low-voltage power supply. Therefore, the circuit configuration is complicated, and the whole apparatus has to be enlarged. Although it is possible to reduce the voltage by voltage drop without using the fork transformer 41,
For example, when a low voltage of DC12V is generated from a high voltage of DC280V, the power consumed by the resistor is too large, and there is a problem of overheating due to heat generation or a need to select a resistor that can withstand a permissible loss. It was difficult to reduce the size of the entire device. Furthermore, in the conventional brushless motor as described above, the rotation speed changes due to the fluctuation of the applied voltage,
The rotation speed also changed due to the load fluctuation. Therefore, in order to stabilize the rotation speed of the motor 1, a constant speed control is usually performed. And it had a speed control circuit for performing this constant speed control. Further, depending on the application, it is necessary to arbitrarily control the number of revolutions of the motor 1, and a speed control circuit different from the above-described speed control circuit has been provided for performing this speed control. Therefore, the circuit configuration was complicated. SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-voltage brushless motor that can simplify the circuit configuration and wiring, reduce the size of the entire device, and perform stable speed control.

[0004]

A high-voltage brushless motor according to the present invention includes: a motor drive circuit that controls a motor at a variable speed by a DC high voltage supplied from a power supply;
A chopper circuit provided in the motor to generate a DC low voltage without using a transformer, and a pre-drive output that detects the rotation speed of the motor and generates a speed pulse to drive the motor drive circuit and outputs a speed command voltage And a pre-drive circuit that performs PWM control by using the DC low voltage generated by the chopper circuit as a self-power supply, performs voltage control, generates a speed pulse and a speed command voltage from the DC low voltage, and drives the motor at a variable speed. Is what you do.

Further, a low DC voltage produced by a chopper circuit is used as a power supply on the control side.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In the high-voltage brushless motor of the present invention, the chopper circuit 14 built in the motor 1 operates as a low-voltage power supply, and converts a DC high voltage to a DC low voltage without using a transformer. Then, a pre-drive circuit also built in the motor 1 controls the chopper circuit 14 as a self-power source, detects the rotation speed of the motor, and generates a speed pulse.
The motor drive circuit 19 is PWM-controlled by the speed command voltage 11 generated by the motor control circuit 7 according to the speed pulse and the output voltage of the chopper circuit, and the rotation of the motor is appropriately controlled. A low-voltage power supply circuit or a plurality of power supplies are not required, the circuit configuration is small and simple, and rotation fluctuations due to power supply voltage fluctuations and load fluctuations can be suppressed.

FIG. 1 is a circuit diagram showing a control circuit of a high-voltage drive brushless motor according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a DC brushless motor having a built-in various control mechanism and a stator having a three-phase coil structure, 3 denotes an AC power supply of AC100V or AC200V, and 4 denotes a rectifier circuit for rectifying the AC to DC130V-DC300V. 5 is a capacitor for smoothing the rectified DC, 6 is a speed command generating circuit for generating a speed command voltage for controlling the rotation speed of the motor 1, 7 is a motor control circuit that operates using the motor 1 as a drive source, and 8 is a motor control circuit. Input voltage which is a high DC voltage input to the motor 1, 9 is ground, 10 is an output voltage which is a low DC voltage output from the motor 1, 11 is a speed command voltage for controlling the rotation speed of the motor 1, 12 is A speed pulse 13 generated according to the rotation speed of the motor 1 is a speed command output output from the motor control circuit 7 to the speed command generation circuit 6.

The high-voltage driven brushless motor having this configuration is divided into a motor side and a control side, and a low-voltage power supply (not shown) is built in the motor 1. Then, it is driven by a single high voltage. That is, the motor 1 is driven only by a DC high-voltage power supply obtained by rectifying an AC power supply 3 by a rectifier circuit 4 and a capacitor 5. DC130V to DC300V
When the input voltage 8 is input, the motor 1 generates a low voltage 12V, outputs this as an output voltage 10, and uses the low voltage as its own power source to control the motor inside the motor 1 (see FIG. 1). (Not shown). The motor control circuit 7 is also driven by the output voltage 10 from the motor 1, and the speed command generation circuit 6 is controlled to apply a speed command voltage 11 to the motor. And this speed command voltage 1
The motor 1 rotates at a constant number of revolutions corresponding to 1. In addition,
The speed pulse 12 is a speed detection pulse (encoder output) provided for the purpose of increasing the accuracy on the control side.

Next, the high voltage brushless motor will be described separately for the motor side and the control side. First, the motor side will be described. FIG. 2 is a circuit diagram showing an internal circuit configuration of a high-voltage drive brushless motor according to an embodiment of the present invention. In the figure, the same reference numerals and symbols as those in FIG. 1 indicate the same or corresponding components. In the figure, reference numeral 2 denotes a detector comprising Hall elements 2a, 2b, 2c and the like, and the detector 2 detects the magnet position of the rotor of the motor 1. 14 is a chopper circuit for converting a DC high voltage of the input voltage 8 into a DC low voltage without using a transformer, 15 is a switching circuit for performing switching at a predetermined cycle to drop a high voltage to a predetermined low voltage, 16 Is a coil for storing energy, 17 is a diode for reflux, 18 is a capacitor for smoothing a low voltage direct current, and the chopper circuit 14 is a switching circuit 15, a coil 16, a diode 17, and a capacitor 18 described above. It is composed of 19a, 19b, 19
c is a motor drive circuit for directly controlling the driving of the motor 1. Reference numeral 20 denotes an IC that functions as a pre-drive circuit that drives the motor drive circuit 19.

Reference numeral 21 denotes a self-power control circuit functioning as a control means of the chopper circuit 14, and more specifically, an overvoltage protection circuit, a starting reference voltage circuit, an undervoltage protection circuit, an error amplifier circuit, a chopper PWM circuit, and the like. It consists of. Each of these circuits operates as follows. The overvoltage protection circuit asynchronously issues an off command to the switching circuit 15 when the applied voltage Vout of the IC 20 becomes equal to or higher than a predetermined voltage. Start reference voltage circuit is IC20
When the applied voltage is lower than a predetermined voltage, an ON command is issued to the switching circuit 15. Error amplifier circuit is IC2
The applied voltage of 0 is amplified around a predetermined voltage to amplify the variation to obtain a comparison voltage for the chopper PWM circuit. The chopper PWM circuit compares the trapezoidal wave with the output of the error amplifier circuit, and generates an on / off command for the switching circuit 15.

Reference numeral 22 denotes a Hall input circuit, which inputs the outputs from the Hall elements 2a, 2b, and 2c differentially and converts them into a square wave. Reference numeral 23 denotes a three-phase full-wave logic circuit, which controls the pre-drive upper output circuit 27 and the pre-drive lower output circuit 28 in accordance with the rotor magnet position obtained from the three-phase Hall input circuit 22 to control the output stage. By turning on / off, the motor 1 is driven in a desired rotation direction.
24 is a PWM control circuit, which is a three-phase full-wave logic circuit 2
3 and the output of the speed control circuit 25, a PWM control signal is generated, and the pre-drive lower output circuit 28 is subjected to PWM control. Reference numeral 25 denotes a speed control circuit for appropriately controlling the number of revolutions of the motor 1 according to a speed command from the outside.
/ V pulse generation circuit, control amplifier circuit, and IC 20
Is composed of a resistor and a capacitor located outside the device. The F / V pulse generation circuit generates a pulse having a constant width in accordance with the switching timing of the output stage from the three-phase full-wave logic circuit 23. The control amplifier circuit is composed of a general operational amplifier. The non-inverting input receives the speed command control, the inverting input receives the output from the F / V pulse generating circuit, and the resistor and the capacitor located outside the IC 20. And constitute a speed loop. Reference numeral 26 denotes a speed pulse generating circuit for generating a predetermined pulse in accordance with the number of rotations of the motor 1 detected by the detector 2, reference numeral 27 denotes a pre-drive upper output circuit, and reference numeral 28 denotes a pre-drive lower output circuit. The output circuit 27 and the pre-drive lower output circuit 28 include a motor drive circuit 19a,
9b and 19c are driven.

The logic portion of the IC 20 is IIL
(Integrated Injection Log
ic), and the linear part is formed by a bipolar process. A motor drive circuit 19 for controlling the speed of the motor 1 on the motor side of the high-voltage brushless motor and a chopper circuit 14 for converting a DC high voltage to a DC low voltage are constituted by a high-voltage circuit. A pre-drive circuit for controlling the drive circuit 19 is formed as an IC and is constituted by a low-voltage circuit.

Here, the operation of the chopper circuit 14 and the pre-drive circuit built in the motor 1 will be described. The chopper circuit 14 functions as a low power supply voltage device together with the self power supply control circuit 21 in the IC 20. That is, when a high DC voltage is applied to the switching circuit 15, the switching circuit 15 is turned on, and a predetermined voltage is output from a connection point between the coil 16 and the capacitor 18. When this potential becomes equal to or higher than a predetermined potential, the self-power control circuit 21 turns off the switching circuit 15 and a return current flows through the diode 17. The coil 16
When the potential at the connection point between the capacitor and the capacitor 18 becomes equal to or lower than a predetermined potential, the self-power control circuit 21 turns the switching circuit 15 on. As described above, the self-power control circuit 21 turns the switching circuit 15 on and off, thereby converting a high voltage to a predetermined low voltage.

As described above, in the embodiment of the present invention, the self-power control circuit 21 for controlling the chopper circuit 14 is integrated with the IC 20 functioning as a pre-drive circuit. The self-power control circuit 21 appropriately controls the chopper circuit 14 in accordance with the power consumption of the IC 20 and the like to generate a stable DC low voltage. And this IC2
0 starts operation only by applying a slight voltage of about 5 V, and thereafter, as described above, the chopper circuit 14 operates at about 1
A low voltage of about 2 V is generated and used as a self-power supply. Therefore, no special low voltage power supply circuit or multiple power supplies are required for the operation of the pre-drive circuit. The pre-drive circuit controls the driving of the motor drive circuit 19 to control the rotation speed of the motor 1. That is, the voltage is converted into a voltage corresponding to the number of revolutions of the motor 1 by the F / V pulse generation circuit, the voltage is compared with the speed command voltage 11, and converted into a voltage to be applied to the motor 1 by an amplification phase assurance circuit or the like. Then, a PWM control signal is generated by using this voltage and a carrier wave such as a sawtooth wave of a predetermined frequency, and the voltage is controlled according to the pulse width. It rotates at a predetermined speed. Therefore, in the example of this embodiment, the rotation speed of the motor 1 is maintained at a stable rotation by the PWM control. Further, in this embodiment, since the pre-drive circuit is formed into an IC and is built in the motor 1, the whole motor is compactly constructed.

Next, the control side of this high-voltage driven brushless motor will be described. FIG. 3 is a circuit diagram showing an example of a speed command voltage generating circuit for a high-voltage drive brushless motor according to the present invention. In the figure, the same reference numerals and symbols as those in FIG. 1 indicate the same or corresponding components. In the figure, 30 is a transistor, 31 to 34 are resistors, 35
Is a capacitor, and constitutes a low-pass filter for stabilizing the speed command voltage 11 with the resistor 34 and the capacitor 35;
The speed command voltage 11 is stabilized. The transistor 30 repeats on / off operations by the motor control circuit 7. In the speed command generating circuit having this configuration, the output voltage 10 is divided by turning on / off the transistor 30. If the on / off duty ratio is changed linearly, that is, linearly, the rotation of the motor 1 is changed. The number can also be controlled linearly.

FIG. 4 is a circuit diagram showing another example of a speed command voltage generating circuit for a high voltage driven brushless motor according to the present invention. In the figure, the same reference numerals and symbols as those in FIG. 1 indicate the same or corresponding components. In the figure, 30a, 3
0b and 30n are transistors, 31a, 31b and 31
n, 32a, 32b, 32n, 33a, 33b, 33
n and 36 are each a resistor. In the speed command generating circuit 6 having this configuration, the motor control circuit 7 controls the on / off state of the n transistors 30a, 30b, and 30n appropriately, so that the total resistance value of the n resistors 31a, 31b, and 31n changes. . Then, the speed command voltage 11 given by the division ratio with the resistor 36 is obtained. That is, the speed command voltage 11 is obtained by the following equation. Speed command voltage 11 = {resistance value of resistor 36 / (resistance value of resistor 36 + total resistance value of resistors 31a, 31b, 31n)} * Vout Therefore, in this speed command generating circuit 6, it is determined by the number of n transistors. Speed command voltage 11 by n raised to the number of states 2
Can be set. The driving of the motor control circuit 7 is controlled by a speed pulse 12 from the motor side.

FIG. 5 is a characteristic diagram showing the relationship between the rotation speed and the speed command voltage of the brushless motor driven by high voltage according to the present invention. In this way, by changing the speed command voltage 11, the rotation speed of the motor 1 can be linearly controlled from 0 to the maximum rotation speed, and the rotation speed of the motor 1 is proportional to the magnitude of the speed command voltage 11. The numbers increase. Further, if the speed command voltage 11 is fixed to a predetermined voltage value, the motor 1 performs stable constant speed driving at a predetermined rotation speed corresponding to the speed command voltage 11. As described above, the high-voltage driven brushless motor of this embodiment uses the motor drive circuit 19 that controls the motor 1 at a variable speed with the high DC voltage, and uses the DC high voltage transformer built in the motor 1. A chopper circuit 14 for converting the voltage to a low DC voltage without a power supply, and a chopper circuit 14 which is also built in the motor 1 and is controlled by a self-power supply control circuit 21 to be a self-power supply, and the rotation speed of the motor 1 is detected by a detector 2. A speed pulse generation circuit 26 generates a speed pulse, and performs a PWM control of a pre-drive output for driving the motor drive circuit 19 with the speed command voltage 11, and generates a speed command based on the speed pulse and the output voltage of the chopper circuit 14. A motor control circuit for generating a speed command voltage by a circuit;

The self-power control circuit 21 in the pre-drive circuit appropriately controls the chopper circuit 14 to generate a stable DC low voltage and use it as a self-power source. The output is supplied to the power supply of the motor control circuit 7. Also, the PW in the pre-drive circuit
By the PWM control by the M control circuit 24 and the speed control circuit 25, the rotation speed of the motor 1 is controlled to be constant, and the rotation speed of the motor 1 is appropriately controlled according to the speed command voltage 11. Therefore, this high-voltage drive brushless motor does not require a special low-voltage power supply circuit or a plurality of power supplies for operating the pre-drive circuit, and the pre-drive circuit having a self-power supply function is built in the motor 1. The whole motor can be downsized.

Further, in this high-voltage driven brushless motor, the rotation speed does not change due to the fluctuation of the applied voltage, and the rotation speed does not change due to the fluctuation of the load, and stable constant speed rotation can be maintained. In addition, the speed control for maintaining the rotation speed of the motor 1 constant and the speed control for maintaining the rotation speed arbitrarily can be performed by one speed control circuit, so that the circuit configuration can be further simplified and the motor can be downsized. Can be promoted. In particular, the pre-drive circuit is integrated into an IC as in this embodiment,
If the self-power control circuit 21 and the speed control circuit are incorporated in the internal control means, the number of components can be reduced and the whole apparatus can be downsized. By the way, in the above-described embodiment, the DC low voltage for the self-power supply generated on the motor side is supplied only to the motor control circuit 7 on the control side, but it can be supplied to the power supply for other mechanisms.

[0020]

As described above, the high-voltage driven brushless motor of the present invention comprises a motor drive circuit for controlling the brushless motor at a variable speed by a DC high voltage supplied from a power supply, and a DC high voltage provided in the brushless motor. A chopper circuit that generates a low DC voltage without using a transformer, and a predrive circuit that detects a rotation speed of a brushless motor, generates a speed pulse, and controls a predrive output that drives a motor drive circuit by PWM using a speed command voltage. The DC low voltage generated by the chopper circuit is used as a self-power supply to perform voltage control, and a speed pulse and a speed command voltage are generated from the DC low voltage, and the brushless motor is driven at a variable speed. It does not require a voltage power supply circuit or multiple power supplies. The rotational fluctuation can be suppressed, the rotation speed of the motor is extremely stable.

The high-voltage driven brushless motor of the present invention uses the low DC voltage generated by the chopper circuit as the power supply on the control side, and thus supplies a stable low DC voltage for the power supply of other mechanisms outside the motor. You can do it.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a control circuit of a high-voltage drive brushless motor according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an internal circuit configuration of a high-voltage drive brushless motor according to one embodiment of the present invention.

FIG. 3 is a circuit diagram showing an example of a speed command voltage generation circuit of the high voltage drive brushless motor according to one embodiment of the present invention.

FIG. 4 is a circuit diagram showing another example of the speed command generation circuit of the high voltage drive brushless motor according to one embodiment of the present invention.

FIG. 5 is a characteristic diagram showing a relationship between a rotation speed and a speed command voltage of the high-voltage driven brushless motor according to one embodiment of the present invention.

FIG. 6 is a circuit diagram showing a circuit configuration of a conventional brushless motor.

[Explanation of symbols]

1 motor, 2 detector, 3 AC power supply, 4 rectifier circuit, 5 capacitor, 6 speed command generation circuit,
7 Motor control circuit, 8 Input voltage, 9 ground, 1
0 output voltage, 11 speed command voltage, 12 speed pulse, 13 speed command output, 14 chopper circuit,
15 switching circuit, 16 coil, 17 diode, 18 capacitor, 19 motor drive circuit, 20 IC, 21 self power control circuit, 2
2 Hall input circuit, 23 3-phase full wave logic circuit,
24 PWM control circuit, 25 Speed control circuit, 26
Speed pulse generation circuit, 27 pre-drive upper output circuit, 28 pre-drive lower output circuit, 30 transistor, 31 resistor, 32 resistor, 33 resistor, 34 resistor, 35 capacitor.

Claims (2)

[Claims] 1. A motor drive circuit for controlling a brushless motor at a variable speed by a DC high voltage supplied from a power supply, and a chopper provided in the brushless motor for generating the DC low voltage without using a transformer. A pre-drive circuit that detects a rotation speed of the brushless motor, generates a speed pulse, and performs a PWM control on a pre-drive output for driving the motor drive circuit by a speed command voltage, and is formed by the chopper circuit. A high voltage drive brushless motor characterized in that voltage control is performed using the low DC voltage as its own power source, the speed pulse and the speed command voltage are generated from the low DC voltage, and the brushless motor is driven at a variable speed. 2. The high-voltage driven brushless motor according to claim 1, wherein a low DC voltage generated by a chopper circuit is used as a power supply on a control side.