JP2536010B2 - 3-phase brushless motor device - Google Patents

Description

The present invention relates to a three-phase brushless motor device capable of performing stop control, that is, brake control.

[Prior Art] A three-phase inverter (DC-AC converter) is connected between a stator winding of a three-phase brushless motor and a DC power supply, and DC is converted to three-phase AC to fix a three-phase Y connection. Supplying a child winding is known, for example, from US Pat. No. 4,249,116.

Further, in order to perform the stop control of this type of three-phase brushless motor, as shown in FIG. 4, the three-phase stator windings 1a, 1b,
Mechanical switches S1 and S2 are connected between the three-phase power lines 2a, 2b and 2c to which 1c is connected, and when the power is off, switches S1 and S2 are turned on in response to relay Ry, and the stator winding 1a,
It is also practiced to electrically brake by forming a closed circuit including 1b and 1c.

[Problems to be Solved by the Invention] However, switches S1 and S2 dedicated to the brake shown in FIG.
Since a relatively large current flows through the switch, not only the switches S1 and S2 become expensive, but also the device becomes large. Also,
Since the switches S1 and S2 are mechanical switches, their reliability was low.

It is disclosed in Japanese Patent Laid-Open No. 172992/1983 that a transistor is used to form a short circuit to apply braking to the motor when the motor is shifted from high speed to low speed. However, this document does not disclose a braking method for stopping the motor by cutting off the power supply voltage.

Therefore, an object of the present invention is to provide a three-phase brushless motor device that can easily and reliably perform braking when stopping the motor by shutting off the power supply voltage.

[Means for Solving the Problems] The present invention for achieving the above object provides a motor including a rotor including permanent magnets and a stator including first, second and third stator windings. A first and a second power supply terminal for supplying a DC voltage, a first transistor connected between the first power supply terminal and the first stator winding, and the first A second transistor connected between the stator winding and the second power supply terminal, and a third transistor connected between the first power supply terminal and the second stator winding. A fourth transistor connected between the second stator winding and the second power supply terminal, and a fourth transistor connected between the first power supply terminal and the third stator winding And a sixth transistor connected between the third stator winding and the second power supply terminal. A first and second for converting a DC voltage between the transistor and the first and second power supply terminals into a three-phase AC voltage for applying to the first, second and third stator windings. 2, third, fourth,
A control signal for the fifth and sixth transistors is formed and supplied to the first, second, third, fourth, fifth and sixth transistors, and a voltage is supplied to the first and second power supply terminals. A DC-AC conversion control circuit for stopping the supply of the control signal to the first, second, third, fourth, fifth and sixth transistors when the power is cut off; and the first and second power supplies. A capacitor connected between the terminals via a backflow blocking diode; a power supply voltage detection resistor connected between the first and second power supply terminals without the backflow blocking diode; It has a series circuit of a resistor and a zener diode connected between both terminals, a pair of power supply connection terminals, first and second input terminals and an output terminal, and the pair of power supply terminals are provided at both ends of the capacitor. Connected, said first The input terminal is connected to the detection voltage transmission line of the power supply voltage detection resistor, the second input terminal is connected to the interconnection point of the resistor and the Zener diode, and the voltage detected by the power supply voltage detection resistor is A voltage comparator formed to convert the voltage at the output terminal from a first level to a second level when changing across a reference voltage obtained by a zener diode; and an output voltage of the voltage comparator. And a means for controlling at least two of the second, fourth and sixth transistors to turn on simultaneously in response to the second level.

[Operation and Effect of the Invention] According to the present invention, the following operation and effect can be obtained.

(A) Even if the supply of the power supply voltage to the first and second power supply terminals is cut off, the capacitor is driven as a power supply to the comparator to turn on at least two of the second, fourth and sixth transistors. Can be That is, it becomes unnecessary to provide a power source for control separately from the power source connected to the first and second power source terminals, and the brake control at the time of stop can be performed with a simple circuit.

(B) A comparator detects a voltage drop between the first and second power supply terminals to turn on at least two of the second, fourth, and sixth transistors, and also controls the first and second transistors.
The control signal supply from the DC-AC conversion control circuit to the first, second, third, fourth, fifth and sixth transistors is stopped by shutting off the voltage supply to the power supply terminal of It is possible to achieve automatic brake control with time with a simple circuit configuration.

[Embodiment] Next, a three-phase brushless motor device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In FIG. 1, the motor M is Y-connected and has three-phase power supply lines 2a, 2
first, second and third stator windings 1 connected to b, 2c
It has a stator including a, 1b and 1c, and a rotor 4 composed of a permanent magnet coupled to a motor shaft 3. A first, a second and a third stator winding 1a wound around a stator core (not shown),
When a three-phase AC voltage is applied to 1b and 1c, a rotating magnetic field is generated and the rotor 4 rotates on the principle of a three-phase synchronous motor.

The inverter circuit 5 for driving the motor M is a three-phase bridge type inverter circuit, and has a first power supply terminal 6
Transistor Q1 connected between the first stator winding 1a and the first stator winding 1a, and a second transistor Q2 connected between the first stator winding 1a and the second power supply terminal 7 And a third transistor Q3 connected between the first power supply terminal 6 and the second stator winding 1b, and between the second stator winding 1b and the second power supply terminal 7. The connected fourth transistor Q4 and the first
The fifth transistor Q5 connected between the power supply terminal 6 and the third stator winding 1c, and the fifth transistor Q5 connected between the third stator winding 1c and the second power supply terminal 7. 6 transistors Q6. It should be noted that the first to
The sixth protection diodes D1 to D6 are connected.

The rotor position detector 8 is a well-known one which is composed of Hall elements arranged on the side of the stator at electrical angle intervals of 120 degrees, and is based on the output of the Hall elements as shown in FIGS. 3 (A) (B) (C). It outputs the indicated rotor position signals Ha, Hb, Hc.

The DC-AC conversion control circuit 9 is connected to the rotor position detector 8, and the rotor position signals Ha, Hb, and
In response to Hc, FIG. 3 (D) (E) (F) (G) (H)
The control signals of the first to sixth transistors Q1 to Q6 shown in (I) are formed and supplied to the bases of the first to sixth transistors Q1 to Q6. The power supply terminal of the DC-AC conversion control circuit 9 is connected to the first and second power supply terminals 6 and 7. Since the control circuit 9 for forming the control signals shown in FIGS. 3D to 3I is well known in the three-phase brushless motor and the three-phase inverter, detailed description thereof will be omitted.

The first and fourth transistors Q1 and Q4 are simultaneously turned on based on the control signals of FIGS.
Transistors Q1 and Q6 are simultaneously turned on, third and sixth transistors Q3 and Q6 are simultaneously turned on, third and second transistors Q3 and Q2 are simultaneously turned on, and fifth and second transistors Q5 and Q2 are simultaneously turned on , Fifth and fourth transistors Q
When 5 and Q4 are simultaneously turned on in this order, three-phase alternating current is obtained in the power supply lines 2a, 2b, and 2c.

The stop control circuit 10 is provided in accordance with the present invention, the power supply lines 11 and 12 are connected to the first and second power supply terminals 6 and 7 of the inverter circuit 5, and the output line 13 is a reverse current blocking diode. It is connected to the bases of the second, fourth and sixth transistors Q2, Q4 and Q6 via D7, D8 and D9. The stop control circuit 10 is configured to drive the second, fourth, and sixth transistors Q2, Q4, and Q6 to turn on in response to turning off the power, and to electrically brake the motor M.

FIG. 2 shows the stop control circuit 10 of FIG. 1 in detail. Power supply voltage detection resistors 14 and 15 are connected between the pair of power supply lines 11 and 12, and a power supply capacitor 17 is connected via a reverse current blocking diode 16. A zener diode 19 for obtaining a reference voltage is connected via a resistor 18 across the capacitor 17. The voltage comparator 20 is for detecting power off or reduction, one input terminal of which is connected to the voltage dividing point of the power voltage detecting resistors 14 and 15,
The other input terminal is connected to the cathode of the Zener diode 19. Also, the power supply terminal of the comparator 20 is a capacitor
Connected to both ends of 17. The base of the driving transistor 21 is connected to the output terminal of the comparator 20, the emitter is connected to one end of the capacitor 17, and the collector is connected to the output line 13.

(Operation) When the drive voltage is normally supplied to the inverter circuit 5, the DC-AC conversion control circuit 9 causes the drive circuit of FIG.
A control signal as shown in (I) is generated, and the DC voltage of the first and second power supply terminals 6 and 7 is converted into an AC voltage and supplied to the motor M.

After that, when the power supply by the first and second power supply terminals 6 and 7 is cut off, the formation of the control signal based on the DC-AC conversion control circuit 9 becomes impossible, and the transistors Q1 to Q6 are connected to the transistors shown in FIG. The control signals as shown in D) to (I) are not supplied.

By the way, since the capacitor 17 in FIG. 2 is charged before the power is cut off, it functions as a power source even after the power is cut off. The comparator 20 detects that the voltage at the voltage dividing point of the resistors 14 and 15 has become lower than the reference voltage given by the Zener diode 19, outputs a low level output, and the stop drive transistor 21 is turned on. As a result, the base current is supplied to the second, fourth and sixth transistors Q2, Q4, Q6 of the inverter circuit 5 by using the capacitor 17 as a power source, and these transistors Q2, Q4, Q6 are turned on at the same time. For this reason,
The stator windings 1a, 1b, 1c are short-circuited by the second, fourth and sixth transistors Q2, Q4, Q6, an electrical braking state occurs, and the rotation of the rotor 4 stops rapidly. .

 This embodiment has the following advantages.

(1) Conversion transistors Q2, Q of the inverter circuit 5
Since the stop control of the motor M is performed by also using 4 and Q6, a switch dedicated to the stop control is not required, and the motor device can be downsized and the cost can be reduced.

(2) Since the transistors Q2, Q4, and Q6 are used without using a mechanical switch for stop control, reliability is improved.

(3) Since the capacitor 17 is provided, the transistors Q2, Q4 and Q6 can be driven after the power is cut off.

(4) Since the comparator 20 detects the power interruption, the brake can be automatically applied.

[Modifications] The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example.

(1) Three transistors Q2, Q4, Q6 during stop control
The braking effect can be obtained even if two selected from are turned on at the same time.

(2) The rotor position detector 8 may be configured by using a proximity switch, a photoelectric conversion element (photocoupler), a rotary transformer, etc. without using a magnetically sensitive element such as a Hall element.

(3) In order to control the voltage applied to the motor M, the third
The pulse width of the control signal shown in FIGS. 7D to 7I may be controlled, or a high frequency chopper circuit may be provided at the input stage of the inverter circuit 5 to control the duty ratio of this output pulse.

(4) The DC-AC conversion control circuit 9 is formed so as to form the control signals of FIGS. 3D to 3I based on the rectangular wave pulse generation circuit without depending on the output of the rotor position detector 8. You may comprise.

(5) It can also be applied to stop control other than when the power is cut off. In this case, the first, third and fifth transistors Q1, Q3 and Q5 of the inverter circuit 5 may be turned off and the second, fourth and sixth transistors Q2, Q4 and Q6 may be turned on. .

(6) The transistors Q1 to Q6 may be field effect transistors (FETs).

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a three-phase brushless motor device according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing the stop control circuit of FIG. 1 in detail, and FIG. 3 shows the state of each part of FIG. FIG. 4 is a circuit diagram showing a part of a conventional three-phase brushless motor. Q1 to Q6 …… Transistor, 1a …… First stator winding, 1b
...... Second stator winding, 1c ... Third stator winding, 4 ...
… Rotor, 5 …… Inverter circuit, 9 …… DC-AC conversion control circuit, 10 …… Stop control circuit.

Claims (1)

(57) [Claims] 1. A motor comprising a rotor composed of permanent magnets and a stator including first, second and third stator windings, and first and second power supplies for supplying a DC voltage. A terminal, a first transistor connected between the first power supply terminal and the first stator winding, and a first transistor connected between the first stator winding and the second power supply terminal A connected second transistor; a third transistor connected between the first power supply terminal and the second stator winding; a second stator winding and the second transistor; A fourth transistor connected between the power supply terminal and the fifth transistor, a fifth transistor connected between the first power supply terminal and the third stator winding, and a third stator winding A sixth transistor connected between a line and the second power supply terminal, and between the first and second power supply terminals Wherein the flow voltage first,
The first, second, third, fourth and fifth for converting into a three-phase AC voltage to be applied to the second and third stator windings.
And a control signal for the sixth transistor is formed and supplied to the first, second, third, fourth, fifth and sixth transistors, and voltage supply to the first and second power supply terminals is cut off. When it is given, the first, second, third, fourth, fifth
And a DC-AC conversion control circuit for stopping the supply of the control signal to the sixth transistor, a capacitor connected between the first and second power supply terminals via a backflow blocking diode, and the backflow blocking Voltage detection resistor connected between the first and second power supply terminals without a diode for power supply, a series circuit of a resistor connected between both terminals of the capacitor and a zener diode, and a pair of power supplies A pair of power supply terminals connected to both ends of the capacitor, the first input terminal having a connection terminal, first and second input terminals, and an output terminal; and the first input terminal being a detection voltage transmission line of the power supply voltage detection resistor. The second input terminal is connected to the interconnection point of the resistor and the zener diode, and the voltage detected by the power supply voltage detection resistor is connected to the zener diode. A voltage comparator formed to convert the voltage at the output terminal from a first level to a second level when the voltage comparator changes across a reference voltage obtained by an ode; Means for controlling at least two of the second, fourth and sixth transistors to turn on simultaneously in response to the second level.