JPH0837787A - Starting circuit of single-phase motor - Google Patents

Abstract

PURPOSE:To provide a starting circuit of a single-phase motor, which suppresses the cost of a single-phase motor body, which improves the starting characteristic of the single-phase motor and which prevents a rotating torque from being dropped. CONSTITUTION:When a single-phase motor is stopped, it is set to a state that the voltage of a charging-and-discharging circuit 12 alternately reaches an upper-limit value V1 and a lower-limit value V2 at a constant electric-potential which and that a reverse-rotation instruction signal and a forward-rotation instruction signal with reference to the single-phase motor are generated alternately. When the single-phase motor receives a starting instruction but it cannot turn in the forward direction, it starts and turns in the reverse direction. Then, by a discharging pulse which is generated from a discharging-pulse generation circuit 11, the voltage of the charging-and-discharging circuit 12 is discharged forcibly irrespective of a charging-and-discharging state so as to become less than the lower-limit value V2, and the forward-rotation instruction is always generated. Therby, the single-phase motor is started surely to turn in the forward direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting circuit for a single-phase motor which can electrically improve the starting characteristics of the single-phase motor.

[0002]

2. Description of the Related Art Generally, when driving a single-phase motor in which one motor coil is continuously wound around an iron core, an electric angle of 180
The single-phase motor is rotated in a predetermined direction by switching the energization direction to the motor coil every time. By the way, when considering the torque waveform of the single-phase motor, there is always a point where the torque becomes zero, that is, a dead point, every 180 degrees of the electrical angle due to the fact that there is only one motor coil. . Therefore, the start-up characteristics of the single-phase motor are not so good as the start-up characteristics of other multi-phase motors. In the worst case, the single-phase motor may not be able to rotate even when receiving a start command.

Therefore, conventionally, the starting characteristics of the single-phase motor are improved by mechanically and magnetically improving the single-phase motor. Here, the annular magnet rotor and the iron core arranged inside the magnet rotor will be taken up and the above measures will be described below. Specifically, the magnet rotor has an N pole and an S pole every 90 degrees.
It is assumed that the magnetic pole has N magnetic poles (hereinafter, four magnetic poles will be described as an example) in which the poles are alternately repeated, and the iron core has four salient poles facing the four magnetic poles. . Basically,
Although the single-phase motor can be rotated as it is, the starting characteristics are not always good. Therefore, as a first countermeasure, a supplementary pole is provided between the adjacent salient poles at an angle of 45 degrees, and as a second countermeasure, a gap between the inner surface of the magnet rotor and each salient pole of the iron core ( The air gap) was uneven. As a result, the balance of the magnetic field is disturbed within the range that does not affect the rotation of the single-phase motor, the starting characteristics of the single-phase motor are improved, and the rotation direction is compensated. This point is described in JP-A-63-144785.

[0004]

However, in the conventional measures, the iron core constituting the single-phase motor body has to be improved, so that the price of the single-phase motor body is significantly increased. Further, the balance of the magnetic field is lost due to the change in the shape of the iron core, so that there is a problem that the rotational torque is reduced at the cost of improving the starting characteristic.

Therefore, an object of the present invention is to provide a starting circuit for a single-phase motor which can reduce the price of the main body of the single-phase motor, improve the starting characteristics of the single-phase motor, and prevent lowering of the rotational torque. .

[0006]

The present invention has been made to solve the above problems, and is characterized in that a first power supply side transistor and a first power supply side transistor are provided between a power supply and ground. The first power supply side transistor and the second ground side transistor are also connected in series, and the connection point of the first power supply side transistor and the first ground side transistor and the first ground side transistor are connected in series. In the state where the motor coil is connected between the connection point of the second power source side transistor and the second ground side transistor,
Turning on the power supply side transistor and the second ground side transistor to allow a current to flow in one direction of the motor coil, and the second power supply side transistor and the first
In the circuit for driving the single-phase motor by repeating the operation of turning on the ground-side transistor and flowing a current in the reverse direction of the motor coil, in a stopped state of the single-phase motor, a constant potential width of A charging / discharging circuit that repeats charging / discharging, and a command signal that generates a reverse rotation command signal or a normal rotation command signal for the single-phase motor when the voltage of the charge / discharge circuit reaches an upper limit value or a lower limit value of the constant potential width. A generation circuit, a discharge pulse generation circuit that generates a discharge pulse each time the energization direction to the motor coil changes due to rotation of the single-phase motor, and a generation period of the discharge pulse each time the discharge pulse occurs A discharge circuit for sequentially discharging the voltage of the charge / discharge circuit regardless of the charge / discharge state of the charge / discharge circuit,
After the single-phase motor starts to rotate in the forward direction or the reverse direction based on the start instruction, the voltage of the charge / discharge circuit is decreased to the lower limit value of the constant potential width or less to constantly generate the normal rotation command signal. The point is to rotate the single-phase motor in the forward direction based on the forward rotation command signal.

[0007]

According to the present invention, when the single-phase motor is stopped, the voltage of the charging / discharging circuit alternately reaches the upper limit value and the lower limit value of the constant potential width, and the reverse rotation command signal and the normal rotation command to the single-phase motor are generated. Command signals are generated alternately. When the single-phase motor cannot receive the start instruction and cannot rotate in the forward direction, it starts rotating in the reverse direction. Then, by the discharge pulse generated from the discharge pulse generation circuit, the voltage of the charge and discharge circuit is forcibly discharged regardless of the charge and discharge state and falls below the lower limit value,
The forward rotation command signal is always generated. As a result, the single-phase motor is reliably started and rotates in the forward direction.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is an overall view showing a starting circuit of a single-phase motor of the present invention. In FIG. 1, (1) is a first power supply side transistor, and (2) is a first ground side transistor, which are connected in series between the power supply VM and the ground. Similarly,
(3) is a second power supply side transistor, and (4) is a second ground side transistor, which are connected in series between the power supply VM and the ground. Reference numeral (5) is a motor coil, which is a connection point of the emitter of the first power supply side transistor (1) and the collector of the first ground side transistor (2), and the emitter of the second power supply side transistor (3) and the It is connected between the connection point of the collectors of the two ground side transistors (4). The combination of the first power supply side transistor (1) and the second ground side transistor (4) and the combination of the second power supply side transistor (3) and the first ground side transistor (2) are electrically connected. The single-phase motor can be rotated by alternately selecting and turning on every 180 degrees and switching the energization direction to the motor coil (5).

Reference numeral (6) is a Hall element, and the power supply path of the Hall element (6) is connected to the power supply Vcc via the resistor (7) and is also grounded. The hall element (6)
Is for detecting the rotation state of the single-phase motor, and is arranged at a specific position of the stator for detecting the magnetic change of the magnet rotor constituting the single-phase motor. Then, the Hall element (6) outputs sine waves of opposite phases from the two output ends as the magnet rotor rotates. It is assumed that this sine wave changes in alternating current around a predetermined reference voltage. (8) is a hall amplifier,
The sine wave at one output end of the hall element (6) is processed into a rectangular wave. Specifically, the Hall amplifier (8) compares the reference voltage with the magnitude of the sine wave, and determines a rectangular wave having a high level when the sine wave is larger than the reference voltage and a low level when the sine wave is smaller than the reference voltage. Output.
A rotation detection circuit is composed of the hall element (6) and the hall amplifier (8) described above.

(9) is a two-phase distributor, which is a combination A of the first power supply side transistor (1) and the second ground side transistor (4) based on the rectangular wave output of the hall amplifier (8).
And a combination B of the second power supply side transistor (3) and the first ground side transistor (2) are alternately turned on at every 180 electrical degrees to generate two-phase distribution outputs a and b. Is. Specifically, when one output terminal of the Hall amplifier (8) is at high level (or low level), an output a for turning on the transistors (1) and (4) of the combination A is generated, and When one output terminal of the hall amplifier (8) is low level (or high level), internal logic is constructed so as to generate an output b for turning on the transistors (2) (3) of the combination B. There is. Further, (10) is a pre-driver, and the transistors (1), (2) and (3) are used.
In order to turn on (4) sufficiently, the two-phase distributor (9)
Signal processing is applied to the phase distribution outputs a and b. The transistors (1) and (4) of the combination A are the pre-driver (1
0) output a'and the combination B transistors (2) and (3) are driven based on the pre-driver (10) output b '. A drive circuit is composed of the above two-phase distributor (9) and pre-driver (10).

(11) is a discharge pulse generating circuit, which generates a discharge pulse in synchronization with the rising and falling of the rectangular wave output of the Hall amplifier (8) (FIG. 2). The discharge pulse is generated only when the single-phase motor is rotating. (12) is a charging / discharging circuit, which repeats charging / discharging within a constant potential width (V1 to V2: V1> V2) when the single-phase motor is stopped. (13) is a discharging circuit, and the charging / discharging circuit (12) is provided only during the generation period of the discharging pulse.
The voltage is forcibly discharged regardless of the charging / discharging state. (14) is a command signal generation circuit, which generates a forward rotation command signal or a reverse rotation command signal for the single-phase motor according to the voltage of the charging / discharging circuit (12). In particular,
The command signal generation circuit (14) generates a reverse rotation command signal when the charging voltage of the charge / discharge circuit (12) rises to V1,
Further, a normal rotation command signal is generated when the discharge voltage of the charge / discharge circuit (12) drops to V2. The reverse rotation command signal and the normal rotation command signal are applied to the two-phase distributor (9) together with the rectangular wave output of the hall amplifier (8), and the two-phase distributor (9) operates based on these three inputs. Details will be described later.

FIG. 3 shows a main part of FIG. 1, particularly a charging / discharging circuit (1
2), discharge circuit (13), and command signal generation circuit (1
It is a figure which shows the specific circuit of 4). Incidentally, in FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 3, (15) (16) (1
7) is a current mirror-connected transistor, and each emitter is commonly connected to the power supply Vcc. The constant current source (180) connected between the collector of the transistor (15) and ground allows the transistor (15) (16)
A constant current according to the size of each transistor flows through the collector of (17). For example, transistor (15) (1
6) When the size ratio of (17) is set to 1: 2: 1, the transistors (15), (16) and (17) have I and 2 respectively.
The collector current of I, I will flow. In addition, (1
8) and 19) are current-mirror-connected transistors, which have the same size as the transistor (17). The base and collector of the transistor (18) are connected to the collector of the transistor (17), and its emitter is grounded. The collector of the transistor (19) is connected to the collector of the transistor (16) via the diode (20), and its emitter is grounded. The diode (20) plays a role of preventing discharge voltage of a capacitor, which will be described later, from flowing to the transistor (22) side. (21) is the above-mentioned capacitor, which is connected in parallel with the collector-emitter of the transistor (19). Reference numeral (22) is a transistor for forcibly bypassing the collector current of the transistor (16) to the ground side. The collector is connected to the collector of the transistor (16), the emitter is grounded, and the base is a resistor (2
It is connected to the output of the comparator described later via 3). As described above, the charge / discharge circuit (12) is configured.

(24) is the above-mentioned comparator,
The + (non-inverting input) terminal is connected to one end of the capacitor (21) on the non-grounded side. (25) and (26) are the power source Vc
The resistors connected in series between c and ground have the same resistance value, and the reference voltage appearing at the connection point is the comparator (2
4)-(inverting input) terminal. (27)
Is a transistor for varying the reference voltage, the base of which is connected to the output terminal of the comparator (24) via the resistor (28) and the collector of which is connected to the resistors (25) and (26) via the resistor (29). It is connected to the connection point and the emitter is grounded. That is, the reference voltage applied to the-terminal of the comparator (24) varies within the range of V1 to V2 according to the on / off state of the transistor (27). That is, the reference voltage of the comparator (24) has hysteresis. Specifically, V1 = Vcc / 2 and V2 =
It becomes Vcc / 2-α. The command signal generation circuit (14) is configured as described above.

Reference numeral (300) is a transistor constituting the discharge circuit (13), and the base is the discharge pulse generation circuit (1
Connected to the output of 1), the collector is a capacitor (21)
Is connected to one end on the non-ground side, and the emitter is grounded. The operation of the circuit of FIG. 3 described above will be described based on the waveform diagram of FIG. First, consider an initial state in which the single-phase motor is stopped and the discharge pulse generation circuit (11) is in a non-output state and the capacitor (21) is in a non-charged state while the power supply Vcc is turned on. In this case, since the output of the comparator (24) is obviously low level, the transistor (27) is turned off and the comparator (2
The reference voltage applied to the-terminal of 4) is V1. At the same time, the low level output of the comparator (24) turns off the transistor (22), so that the collector current of the transistor (16) flows through the diode (20).

When the collector current I flows through the transistor (17), the current I flows through the collector of the transistor (18).
Of the collector current 2I of the transistor (16) flows through the collector of the transistor (19), and the remaining current I is charged in the capacitor (21) and its terminal voltage rises. After that, when the terminal voltage of the capacitor (21) reaches the reference voltage V1, the output of the comparator (24) is inverted and becomes high level, and the transistor (27).
Turns on and the reference voltage applied to the-terminal of the comparator (24) becomes V2 (<V1). At the same time, the high level output of the comparator (24) causes the transistor (2
2) turns on and the collector current 2 of the transistor (16)
All I are grounded via the collector-emitter path of the transistor (22) and are not output from the diode (20). Therefore, since the current path from the transistor (16) which supplies the collector current I to the transistor (19) is cut off, the capacitor (21) starts discharging and supplies the current I to the collector of the transistor (19). It will be. That is, the terminal voltage of the capacitor (21) drops.

After that, when the terminal voltage of the capacitor (21) reaches the reference voltage V2, the output of the comparator (24) is inverted to the low level, the reference voltage rises to V1, and the capacitor (21) is charged again. Start. When the single-phase motor is stopped, the capacitor (2
1) is repeatedly charged and discharged between reference voltages V1 and V2,
Especially when the capacitor (21) is charging, the reference voltage is V
When the capacitor (21) discharges, the reference voltage becomes V2. In FIG. 6, the reference voltage is indicated by the alternate long and short dash line. Further, the low level output of the comparator (24) corresponds to the forward rotation command signal of the single-phase motor, and the high level output of the comparator (24) corresponds to the reverse rotation command signal of the single-phase motor.

Next, a specific circuit of the two-phase distributor (9) will be described with reference to FIG. In FIG. 4, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 4, (30) and (31) are current mirror-connected transistors, and the transistor (30)
A constant current flows through the collector of the transistor (31) by the constant current source (32) connected between the collector of the power supply Vcc and the power supply Vcc. Further, a switch circuit (33) is provided between the constant current source (32) and the power source Vcc, and is opened / closed under the control of the start command signal. Specifically, when the activation command signal becomes high level, the switch circuit (33) is closed and a constant current flows through the collector of the transistor (31) (34) is output from the comparator (24) F /.
R is a transistor applied to the base, the collector is connected to the power supply Vcc through the resistors (35) and (36), and the emitter is grounded through the resistor (37).
Reference numeral (38) is a transistor which operates according to ON / OFF of the transistor (34), and the base has the transistor (3
Connected to the collector of 4), the collector is a resistor (39)
It is connected to the power supply Vcc via (40), and the emitter is connected to the emitter of the transistor (34). Further, (41) and (42) are differentially connected transistors, and the common emitter is connected to the collector of the transistor (31). That is, when the output F / R of the comparator (24) becomes low level with the switch circuit (33) closed, that is, when the normal rotation command signal of the single-phase motor is generated, the transistor (34) is turned off and the transistor (34) is turned off. 38) turns on. As a result, the resistance (35) (36)
The connection point voltage of is higher than the connection point voltage of the resistors (39) and (40), so that the transistor (42) is turned on and the transistor (41) is turned off. That is, when the forward rotation command signal is generated, the transistor (42) is selected and turned on. On the contrary, when the output F / R of the comparator (24) becomes high level, that is, when the reverse rotation command signal of the single-phase motor is generated, the transistor (38) is turned off along with the turning on of the transistor (34). As a result, the resistance (35) (3
The connection point voltage of 6) becomes lower than the connection point voltage of the resistors (39) and (40), so that the transistor (41) is turned on and the transistor (42) is turned off. That is, when the reverse rotation command signal is generated, the transistor (41) is selected and turned on.

(43) and (44) are differentially connected transistors, the common emitter of which is connected to the collector of the transistor (41). In addition, the transistor (4
The base of 3) is connected to the output of the Hall amplifier (8),
The base of the transistor (44) is connected to the connection point of the resistors (45) and (46) connected in series between the power supply Vcc and the ground. Similarly, (47) and (48) are differentially connected transistors, and the common emitter is connected to the collector of the transistor (42). The base of the transistor (48) is connected to the output of the Hall amplifier (8), and the base of the transistor (47) is a resistor (45).
It is connected to the connection point of (46) and a reference voltage is applied. Further, (49) is a transistor which is current-mirror connected to the circuit in the subsequent stage, the emitter is connected to the power source VM, and the base and collector are transistors (43).
It is connected to the collector of (47). Reference numeral (50) is a transistor that is current-mirror connected to the circuit in the subsequent stage, the emitter is connected to the power supply VM, and the base and collector are connected to the collectors of the transistors (44) and (48).

That is, the two-phase distributor (9) shown in FIG.
The operation is based on the output of the hall amplifier (8) and the forward rotation instruction signal or the reverse rotation instruction signal, and the specific operation is as shown below. For example, when the reverse rotation command signal is generated, the transistor (41) is turned on. Therefore, when the output of the hall amplifier (8) is high level, the transistor (43) is turned on and the transistor (49) is turned on. A current flows in the emitter-collector path, and when the output of the Hall amplifier (8) is at a low level, the transistor (44) turns on and a current flows in the emitter-collector path of the transistor (50). On the contrary, when the forward rotation command signal is generated,
Since the transistor (42) is turned on, when the output of the Hall amplifier (8) is at high level, the transistor (4
8) is turned on and a current flows through the emitter-collector path of the transistor (50), and when the output of the Hall amplifier (8) is at a low level, the transistor (47) is turned on and a current flows through the emitter-collector path of the transistor (49). Flowing. Therefore, in each state where the forward rotation or reverse rotation command signal is generated, the same output of the hall amplifier (8) causes
The transistors (49) or (50) on different sides will be selected.

FIG. 5 is a diagram showing a peripheral circuit of the pre-driver (10) and the motor coil (5). The same components as those shown in FIG. 1 having the same configuration as those shown in FIG. 5 are designated by the same reference numerals, and their description will be omitted. In FIG. 5, reference numeral (51) is a transistor mirror-connected to the transistor (49), the base of which is connected to the base of the transistor (49) and the emitter of which is connected to the power supply VM. The base and collector of the transistor (52) are resistors (53)
Connected to the collector of the transistor (51) via
The emitter is connected to the base of the first ground side transistor (2) and is also connected to the emitter of the first ground side transistor (2) via the resistor (54), that is, is grounded. The base of the transistor (55) is connected to the collector of the transistor (51), and the collector is a resistor (5
6) is connected to the power supply VM via the
It is connected to the base of the first ground side transistor (2) via 7). The transistor (58) has a base connected to the collector of the transistor (55), an emitter connected to the power supply VM, and a collector connected to the base of the second power supply side transistor (3). Where the first
The base current of the ground side transistor (2) of
3) Determined by the resistance ratio of (57). For example, the resistance (5
3) If the resistance ratio of (57) is 10: 1, the base current that is 10 times the collector current of the transistor (51) is
Can be supplied to the base of the ground side transistor (2). Along with this, the second power supply side transistor (3)
The base current of is also increased.

Similarly, (59) is a transistor (5
0) is a current mirror-connected transistor, the base is connected to the base of the transistor (50), and the emitter is connected to the power supply VM. Transistor (60)
Has a base and a collector connected to the collector of the transistor (59) through the resistor (61), an emitter connected to the base of the second ground side transistor (4), and a second via the resistor (62). Ground side transistor (4)
Is connected to the emitter of, that is, is grounded. The base of the transistor (63) is connected to the collector of the transistor (59), and the collector is connected to the power source V via the resistor (64).
It is connected to M, and the emitter is connected to the base of the second ground side transistor (4) through the resistor (65).
The base of the transistor (66) is a transistor (6
3) is connected to the collector, the emitter is connected to the power supply VM, and the collector is connected to the base of the first power supply side transistor (1).

Therefore, when the transistor (49) is turned on, the transistors (51), (52) and (55) are turned on and the first ground side transistor (2) is supplied with a base current sufficient to turn on. Transistor (55) at the same time
When the transistor is turned on, the transistor (58) is turned on, and the base current sufficient to turn on the second power supply side transistor (3) is also supplied. Therefore, a leftward current flows from the second power source side transistor (3) to the first ground side transistor (2) in the motor coil (5).
On the contrary, when the transistor (50) is turned on, the transistors (59), (60) and (63) are turned on, and the second ground side transistor (4) is supplied with a sufficient base current to be turned on, and at the same time, the transistors are simultaneously turned on. As the transistor (63) is turned on, the transistor (66) is turned on, and the base current sufficient for turning on the first power supply side transistor (1) is also supplied. Therefore, the motor coil (5) includes the first power source side transistor (1) to the second ground side transistor (4).
A current flowing in the right direction will flow. In this way, the single-phase motor can be rotated by switching the energization direction to the motor coil (5).

The operation of the present invention will be described below with reference to the waveform chart of FIG. First, the start command is not given to the single-phase motor,
In the state in which the single-phase motor is stopped, the capacitor (21) is in a state of repeating charging / discharging between the voltages V1 and V2, and a forward rotation command signal or a normal rotation command signal depending on charging / discharging of the capacitor (21). The reverse rotation command signal is repeatedly generated. At this time, as a matter of course, no discharge pulse is generated from the discharge pulse generation circuit (11), and both ends OUT1 and OUT2 of the motor coil (5) are in a high impedance state (three-dot chain line).

Thereafter, at time t0, the start command signal is set to a high level for the purpose of rotating the single-phase motor, the switch circuit (33) is closed, and the two-phase distributor (9) shown in FIG.
To the operating state. At this point, the forward rotation command signal for rotating the single-phase motor in the forward direction is generated.
Assuming that the positive direction rotational torque generated from the positional relationship between the magnetic poles of the magnet rotor and the iron core constituting the single phase motor is zero, that is, at the dead center, the single phase motor cannot rotate in the positive direction and remains stopped. . Therefore, since the discharge pulse is not generated and the transistor (300) remains off, the capacitor (21) continues to be charged until its terminal voltage reaches V1. During this period, according to the output level of the Hall amplifier (8), the transistor (49) is turned on as the transistor (47) is turned on, and the voltage O across the motor coil (5) is
It is assumed that UT1 and OUT2 are at low level and high level, respectively.

After that, at time t1, when the terminal voltage of the capacitor (21) reaches V1, the output of the comparator (24) is inverted and becomes high level, so that the capacitor (21) starts discharging. At the same time, a high-level reverse rotation command signal is generated to try to rotate the single-phase motor in the reverse direction. During this period, since the output of the Hall amplifier (8) does not change, the transistor (50) is turned on as the transistors (41) and (44) are turned on, and the voltages OUT1 and OUT2 of the motor coil (5) are at high level, It has been inverted to low level. Here, the magnetic pole of the magnet rotor and the motor coil (5) constituting the single-phase motor
The dead point of the torque waveform generated by the relative relationship with the wound iron core exists at a different position between the forward rotation torque and the backward rotation torque. Therefore, since the reverse rotation torque of the single-phase motor at the stop position does not reach the dead center, the single-phase motor starts rotating in the reverse direction at time t2. Then, a discharge pulse starts to be generated, the transistor (300) is turned on only during this period, and the terminal voltage of the capacitor (21) is rapidly discharged through the transistor (300). Then, at time t3, when the terminal voltage of the capacitor (21) is discharged to V2, the output of the comparator (24) is inverted to a low level and a normal rotation command signal is generated, and at the same time, the capacitor (21) is discharged. Start charging. Here, in order for the single-phase motor to continue to rotate in the opposite direction, the motor coil (5) changes with the output change of the hall amplifier (8) after time t3.
The voltages OUT1 and OUT2 of the motor coil (5) must be inverted to the low level and the high level, respectively, but since the low level forward rotation command signal is generated after the time t3, the voltages OUT1 and OUT2 of the motor coil (5) are generated. Continues to be high level and low level, and since the single-phase motor once rotated in the reverse direction, the dead point of the forward rotation torque can be avoided, and the single-phase motor starts to rotate in the forward direction.

After that, the terminal pulse due to the charging of the capacitor (21) is repeatedly discharged by the discharge pulse generated by the forward rotation of the single-phase motor, and decreases toward 0 volt. That is, the low-level forward rotation command signal is continuously generated. Therefore, after time t3, the voltage OUT across the motor coil (5) is generated every time a discharge pulse is generated.
1 and OUT2 are switched to a high level or a low level, that is, the energization direction to the motor coil (5) is an electrical angle 1
It is switched every 80 degrees, and the single-phase motor reliably rotates in the forward direction.

As described above, the starting characteristics of the single-phase motor can be surely improved by electrical measures without making mechanical improvement for improving the starting characteristics of the iron core constituting the single-phase motor. Therefore, it is possible to reduce the price of the single-phase motor main body and prevent the reduction of the rotation torque of the single-phase motor.

[0028]

According to the present invention, the starting characteristics of a single-phase motor can be improved by electrical measures without making mechanical improvements for improving the starting characteristics of the iron core constituting the single-phase motor. The single-phase motor can be reliably rotated in the forward direction by the start command. Therefore, there is an advantage that the price of the main body of the single-phase motor can be suppressed and the reduction of the rotation torque of the single-phase motor can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall view of a starting circuit of a single-phase motor of the present invention.

FIG. 2 is a waveform diagram showing a relationship between a discharge pulse and input / output of a Hall amplifier.

FIG. 3 is a diagram showing a main part of the present invention.

FIG. 4 is a diagram showing a main part of the present invention.

FIG. 5 is a diagram showing a main part of the present invention.

FIG. 6 is a waveform chart showing the operation of the present invention.

[Explanation of symbols]

 (1) First power supply side transistor (2) First ground side transistor (3) Second power supply side transistor (4) Second ground side transistor (5) Motor coil (9) Two phase distributor (10) ) Pre-driver (11) Discharge pulse generation circuit (12) Charge / discharge circuit (13) Discharge circuit (14) Command signal generation circuit

Claims (2)

[Claims] 1. A first power supply side transistor and a first ground side transistor are connected in series between a power supply and a ground, and a second power supply side transistor and a second ground side transistor are also connected in series, and In a state where a motor coil is connected between a connection point of the first power supply side transistor and the first ground side transistor and a connection point of the second power supply side transistor and the second ground side transistor,
An operation of turning on the first power supply side transistor and the second ground side transistor to flow a current in one direction of the motor coil, and turning on the second power supply side transistor and the first ground side transistor Then, by repeating the operation of passing a current in the opposite direction of the motor coil,
In a circuit for driving a single-phase motor, in a stopped state of the single-phase motor, a charge / discharge circuit that repeats charging / discharging between constant potential widths, and a voltage of the charge / discharge circuit is an upper limit of the constant potential width. A command signal generation circuit that generates a reverse rotation command signal or a normal rotation command signal for the single-phase motor when the value or the lower limit value is reached, and whenever the single-phase motor rotates and the energization direction to the motor coil changes. A discharge pulse generating circuit that generates a discharge pulse, and a discharge circuit that sequentially discharges the voltage of the charging / discharging circuit irrespective of the charging / discharging state of the charging / discharging circuit for each generation period of the discharging pulse each time the discharging pulse is generated. And, after the single-phase motor starts to rotate in a forward direction or a reverse direction based on a start instruction, lowers the voltage of the charge / discharge circuit to a value equal to or lower than the lower limit value of the constant potential width to perform the normal rotation command. Always emit a signal It is allowed, based on positive rotation command signal, a single-phase motor starting circuit, characterized in that rotating the single-phase motor in the forward direction. 2. A rotation detection circuit for detecting a rotation state of the single-phase motor, a first combination including the first power supply side transistor and the second ground side transistor, and the second power supply side. A drive circuit that selectively turns on a second combination of a transistor and the first ground-side transistor in response to the output of the rotation detection circuit and the normal rotation instruction signal or the reverse rotation instruction signal; The drive circuit receives the output of the rotation detection circuit when the forward rotation instruction signal is generated and when the reverse rotation instruction signal is generated, and selects a different one of the first and second combinations. The starting circuit for a single-phase motor according to claim 1, wherein the starting circuit is selected and turned on.