JP6546035B2 - Sewing machine motor power circuit - Google Patents

Description

  The present invention relates to a power supply circuit of a sewing machine motor.

  The AC power supplies used in each country or region were not standardized in terms of voltage and the total number of single phases and three phases, and were broken down by country and region. For example, the voltage is roughly divided into a band of 100 to 120 V (hereinafter referred to as 100 V band) and a band of 200 to 240 V (hereinafter referred to as 200 V band).

A conventional power supply circuit that rectifies an AC power supply voltage comprises a diode bridge with two inputs connected to the AC power supply and two outputs connected to the load, and between the two outputs of the diode bridge And a switch for switching between the two capacitors and one of the input portions of the diode bridge between a short circuit state and a disconnected state (for example, see Patent Document 1).
In this power supply circuit, full-wave rectification can be performed when the switch is disconnected, and voltage doubled rectification can be performed when the switch is shorted.
The switch is operated in a short-circuited state for the AC power supply of 100 V band to perform voltage doubler rectification, and the AC power supply for 200 V band is operated in the disconnection state of the switch to perform full-wave rectification.

Unexamined-Japanese-Patent No. 11-285253

  However, the conventional power supply circuit does not have a mechanism for causing the outside to recognize the voltage and the number of phases of the AC power supply, and which of full wave rectification and voltage doubler rectification is being performed. For this reason, when it applied as a control circuit of a sewing machine motor, according to the voltage of AC power supply, the number of phases, etc., appropriate control could not be performed.

  An object of the present invention is to provide a power supply circuit of a sewing machine motor that performs appropriate control according to the voltage and the number of phases of an AC power supply.

The invention according to claim 1 is a power supply circuit of a sewing machine motor,
A first diode bridge with two inputs connected to the alternating current source and two outputs connected to the load;
Two capacitors connected in series between the two outputs of the first diode bridge;
A switching unit that switches between the short circuit state and the disconnected state between the middle of the two capacitors and one input of the first diode bridge;
A second diode bridge comprising two inputs connected in parallel to the first diode bridge to the alternating current source,
A voltage detection unit that detects voltages of two outputs of the second diode bridge;
A determination unit which determines the duration of the minimum potential in the continuous change of the detection voltage of the voltage detection unit, and determines from the duration of the minimum potential whether the switching unit is in the voltage doubler rectification state or the full wave rectification state;
And a motor control unit that performs output control of the sewing machine motor from the rectified state determined by the determination unit.

The invention according to claim 2 is the power supply circuit of the sewing machine motor according to claim 1,
The determination unit determines the duration of the maximum potential in the continuous change of the detection voltage of the voltage detection unit, and determines the number of phases of the AC power supply from the duration of the maximum potential.
The motor control unit performs output control of a sewing machine motor from the number of phases of the AC power supply determined by the determination unit.

The present invention can identify which zone of the AC voltage of the AC power supply, and the motor control unit controls the sewing machine motor so that the load of the AC power supply is reduced according to the zone of the AC voltage. It becomes possible.
Furthermore, even when the power is supplied to the sewing machine motor by connecting to an AC power supply of a facility such as a sewing factory using a plurality of sewing machines, generation of voltage drop (flicker) of the power supply is reduced. Good sewing can be performed for a plurality of sewing machines.

It is a block diagram showing a power supply circuit of a sewing machine motor which is an embodiment of the invention. It is a graph which shows the waveform of the detection voltage in case alternating current power supply is a single phase 100V zone. It is a graph which shows the waveform of the detection voltage in case alternating current power supply is a single phase 200V zone. FIG. 6 is a diagram showing a waveform of a detection voltage when the AC power supply is in a three-phase 200 V band.

Summary of the Embodiments of the Invention
Hereinafter, a power supply circuit 10 of a sewing machine motor according to an embodiment of the present invention will be described based on the drawings. The power supply circuit of the sewing machine motor performs power supply and output control to the sewing machine motor 11 which is a sewing drive source of the sewing machine.

The AC power supply supplied to the sewing machine differs in voltage and number of phases in different countries and regions.
Here, as AC power supply, (1) 50 Hz in single phase 100 V band (100 to 120 V), (2) 50 Hz in single phase 200 V band (200 to 240 V), and (3) three phase 200 V band (200 to 240 V) An example in which three types of 50 Hz can be used will be described.
The power supply circuit 10 of the sewing machine motor supplies power by converting it into a DC voltage of 280 V suitable for driving the sewing machine motor 11 even when any of the above three types of AC power supplies is connected. However, when the sewing machine motor 11 is operated with the same output in any of the above (1) to (3), the load on the AC power supply increases in the order of (1), (2) and (3).
Therefore, for example, in an environment where a sewing machine is for industrial use and a large number of machines operate at one time in a factory, in the case of the alternating current power supply of (1) and (2), the load becomes excessive and A voltage drop (flicker) may occur.
Therefore, the power supply circuit 10 of the sewing machine motor is intended to determine the voltage of the AC power supply and the number of phases, and to perform appropriate output control on the sewing machine motor 11.

[Schematic configuration of power supply circuit of sewing machine motor]
FIG. 1 is a block diagram of a power supply circuit 10 of a sewing machine motor.
As illustrated, the power supply circuit 10 of the sewing machine motor includes two input parts 21 and 22 connected to the AC power supply 12 and two output parts 23 and 24 connected to the load (the sewing machine motor side). A first diode bridge 20 and two capacitors 41 and 42 connected in series between the two outputs 23 and 24 of the first diode bridge 20, and between the two capacitors 41 and 42 and a first diode A manual switch 43 as a switching unit that switches one input unit 22 of the bridge 20 to a short circuit state and a disconnected state, and two input units 31 and 32 connected to the AC power supply 12 in parallel with the first diode bridge 20 And a voltage detection unit 44 for detecting the voltage of the two outputs 33 and 34 of the second diode bridge 30; And a two resistors 45 and 46 connected in series between the two outputs 33 and 34 of the diode bridge 30.

[First diode bridge]
The first diode bridge 20 has a diode 25 with an anode terminal connected to the input unit 21 and a cathode terminal connected to the output unit 23, a diode 26 with an anode terminal connected to the output unit 24 and a cathode terminal connected to the input unit 21, A diode 27 has an anode terminal 22 and a cathode terminal connected to the output unit 23, and a diode 28 has an anode terminal connected to the output unit 24 and a cathode terminal connected to the input unit 22.

The output part 23 and the output part 24 of the first diode bridge 20 are respectively connected to the motor drive circuit 52, and between the output parts 23 and 24 and the motor drive circuit 52, a three-phase rectifier circuit is provided. Two diodes 511 and 512 connected in series that form 51 and two capacitors 41 and 42 connected in series are respectively bridged.
The sewing machine motor 11 is an AC servomotor, and the three-phase rectifier circuit 51 further optimizes the current rectified by the first diode bridge 20 and the capacitors 41 and 42 for AC servomotor drive.
Both of the two diodes 511 and 512 connected in series in the three-phase rectification circuit 51 face the anode terminal toward the output unit 24 and the cathode terminal toward the output unit 23.
When the AC power supplied to the sewing machine is three-phase, the U phase is connected to the input portion 21 of the first diode bridge 20 and the V phase is connected to the input portion 22 of the first diode bridge 20 And the W phase is connected between the two diodes 511 and 512 of the three phase rectifier circuit 51.

[Condenser and manual switch]
Between the middle point of the capacitor 41 and the capacitor 42 and the input portion 22 of the first diode bridge 20, as described above, the manual switch 43 for switching between the short circuit state and the disconnection state is provided. .
The manual switch 43 switches to a short-circuited state when the AC power supply 12 is (1) single phase 100 V band to execute voltage doubler rectification, and the AC power supply 12 performs (2) single phase 200 V band (200 to 240 V) or 3) In the case of three-phase 200 V band, switch to the disconnected state to execute full-wave rectification.

When the manual switch 43 is in a short-circuited state, when the output of the AC power supply 12 is at a positive potential, the input portion 21 of the first diode bridge 20 passes through the output portion 23 and further passes through the capacitor 41 and the manual switch 43 A current flows in a path returning to the power supply 12.
In addition, when the output of the AC power supply 12 is at a negative potential, the current flows through the manual switch 43 and the capacitor 42 from the output unit 24 of the first diode bridge 20 through the input unit 21 to the AC power supply 12. Flows.
As a result, voltage doubler rectification is performed, and the output side is boosted to 280 V DC with respect to 100 V AC on the input side.

Further, when the manual switch 43 is turned off, when the output of the AC power supply 12 is a positive potential, the input portion 21 of the first diode bridge 20 passes through the output portion 23 and then passes through the capacitors 41 and 42, A current flows from the output portion 24 of the first diode bridge 20 through the input portion 22 and returns to the AC power supply 12.
When the output of the AC power supply 12 is a negative potential, the output of the first diode bridge 20 passes through the input 22 of the first diode bridge 20, the output 23 and the capacitors 41 and 42. A current flows from the point 24 to the input part 21 and returns to the AC power supply 12.
As a result, full-wave rectification is performed, and the output side is boosted to 280 V DC with respect to 200 V AC on the input side.

[Second diode bridge]
The second diode bridge 30 has a diode 35 with an anode terminal connected to the input unit 31 and a cathode terminal connected to the output unit 33, a diode 36 with an anode terminal connected to the output unit 34, and a cathode terminal connected to the input unit 31, A diode 37 has an anode terminal 32 and a cathode terminal connected to the output unit 33, and a diode 38 has an anode terminal connected to the output unit 34 and a cathode terminal connected to the input unit 32.

  The input 31 of the second diode bridge 30 is connected to the AC power supply 12 together with the input 21 of the first diode bridge 20, and the input 32 of the second diode bridge 30 is an input of the first diode bridge 20. It is connected to the AC power supply 12 together with the unit 22. Thereby, the first diode bridge 20 and the second diode bridge 30 are connected in parallel to the AC power supply 12.

Two resistors 45 and 46 connected in series are provided between the output section 33 and the output section 34 of the second diode bridge 30, and the voltage detection section 44 detects the potential difference on both sides of the resistor 46. Do.
The voltage detection unit 44 reduces the power supply voltage rectified by the first diode bridge 20 and the capacitors 41 and 42 at a constant ratio by the configuration of the second diode bridge 30 and the resistors 45 and 46. Can be detected.

[Determination unit]
The voltage detection unit 44 is connected to the determination unit 53, and inputs a detection voltage to the determination unit 53.
The determination unit 53 monitors the time-series change of the detection voltage from the voltage detection unit 44, and from the change of the detection voltage, the AC power supply 12 is (1) single-phase 100 V band, (2) single-phase 200 V It is determined which of the band and (3) three-phase 200 V band.

  Here, the method of determination by the determination unit 53 will be described. The determination unit 53 records the detection voltage of the voltage detection unit 44 in time series. Here, FIG. 2 shows the recording of the change of the detection voltage when the AC power supply 12 is (1) in the single phase 100 V band, and FIG. 3 shows the recording of the change in the detection voltage in the (2) single phase 200 V band. And FIG. 4 shows (3) recording of changes in detected voltage in the case of (3) three-phase 200 V band.

Taking FIG. 2 as an example, first, the determination unit 53 obtains the minimum potential Vl which is the minimum value of the obtained detection voltage, and calculates the minimum potential time Tl which is a period in which the minimum potential Vl continues. The minimum potential time Tl can be obtained by obtaining a period in which the potential of the predetermined increase width α continues from the minimum potential Vl, that is, a period in which the potential is in the range of Vl to Vl + α.
Similarly, determination unit 53 obtains maximum potential Vh which is the maximum value of the detected voltage obtained, and calculates maximum potential time Th which is a period in which maximum potential Vh continues. The maximum potential time Th can be acquired by obtaining a period in which the potential with a predetermined decrease width β continues from the maximum potential Vh, that is, a period in which the potential is in the range of Vh-β to Vh.

For example, in the case of (1) single phase 100 V band, (2) single phase 200 V band, and (3) three phase 200 V band, the following numerical values can be obtained as an example.
(1) In the case of single-phase 100 V band, maximum potential: 2.5 V, maximum potential time 4 ms, minimum potential: 1.25 V, minimum potential time 10 ms, repetition time 20 ms (described later)
(2) In the case of single-phase 200 V band, maximum potential: 2.5 V, maximum potential time 4 ms, minimum potential: 0.63 V, minimum potential time 1.5 ms, repetition time 10 ms (described later)
(3) In the case of three-phase 200 V band, maximum potential: 2.5 V, maximum potential time 12 ms, minimum potential: 0.63 V, minimum potential time 2 ms, repetition time 20 ms (described later)

As can be seen from the above example, the minimum potential time is distinctly different depending on whether it is voltage doubler rectification or full wave rectification, so the determination unit 53 predetermines a threshold (for example, about 4 to 8 ms, 6 ms here) for the minimum potential time. Can be determined if the voltage is equal to or higher than the threshold, and if the voltage is lower than the threshold, full-wave rectification is performed.
Also, whether the AC voltage is 100 V band ((1) above) or 200 V band (above (2) or (3)) depending on which of voltage doubler rectification and full wave rectification is performed. Can be determined.

  Furthermore, since the maximum potential time clearly differs depending on whether it is a single phase or three phases, the determination unit 53 defines a threshold (for example, about 6 to 10 ms, here 8 ms) for the maximum potential time in advance. In some cases, it is determined that the number of phases of the AC power supply 12 is three (the above (3)) and the number of phases is single (the above (1) or (2)) if it is less than the threshold. it can.

  As described above, the determination unit 53 identifies all of (1) single-phase 100 V band, (2) single-phase 200 V band, and (3) three-phase 200 V band by dividing the case into the minimum potential time and the maximum potential time. can do.

Furthermore, the determination unit 53 can obtain the power supply frequency of the AC power supply 12 from the determination results of the bands of (1) to (3) and the detection voltage of the voltage detection unit 44.
That is, the determination unit 53 obtains the power supply frequency of the AC power supply 12 by obtaining the repetition cycle of the continuous waveform.

Specifically, as shown in FIGS. 2 to 4, from the recording of the change of the detection voltage, the repetition time Tf from the detection of the minimum potential Vl (or the maximum potential) to the detection of the next minimum potential Vl calculate.
Then, when the band is (1) single-phase 100 V band, the determination unit 53 calculates the power supply frequency (= 1 / Tf) from the reciprocal of the repetition time Tf because (power supply cycle) = (repetition time Tf) Do.
Further, when the band is (2) single-phase 200 V band, determination unit 53 is (power supply cycle) = (repetition time Tf) × 2, so that the power supply frequency (= 1/1) from the reciprocal of repetition time 2 · Tf. Calculate (2 · Tf)).
Further, when the band is (3) three-phase 200 V band, the determination unit 53 calculates the power supply frequency (= 1 / Tf) from the reciprocal of the repetition time Tf because (power supply cycle) = (repetition time Tf). Do.

For example, if the repetition time Tf = 20 [ms] is obtained and the band is (1) single-phase 100 V band, calculate the power supply frequency 50 [Hz] from 1 / Tf = 1/20 [ms]. Can.
Similarly, when the repetition time Tf = 10 [ms] and the band is (2) single-phase 200 V band, 1 / (2 · Tf) = 1 / (2 · 10) [ms] to 50 MHz power supply frequency. Hz], the repetition time Tf = 20 [ms], and the band is (3) three-phase 200 V band, 1 / Tf = 1/20 [ms] to the power supply frequency 50 [Hz] It can be calculated as

[Motor drive circuit]
The three-phase rectifier circuit 51 described above is connected to a motor drive circuit 52 as a motor control unit. In principle, the motor drive circuit 52 receives a speed command from a control device of the sewing machine (not shown) and accelerates the current of the sewing machine motor 11 so as to accelerate at an acceleration according to the difference between the current sewing machine motor 11 and the command speed. Take control. Thus, the sewing machine motor 11 can be driven to achieve the target speed indicated by the speed command of the control device.

Further, the motor drive circuit 52 receives the identification results of (1) single-phase 100 V band, (2) single-phase 200 V band, and (3) three-phase 200 V band from the determination unit 53.
That is, in the motor drive circuit 52, different coefficients K1, K2, and K3 are set for each of (1) single-phase 100 V band, (2) single-phase 200 V band, and (3) three-phase 200 V band. The sewing machine motor 11 is accelerated such that "acceleration corresponding to the difference between the current sewing machine motor 11 and the command speed" in current control of the motor 11 is accelerated by an acceleration obtained by multiplying the coefficients K1, K2 and K3 according to the identification result. Control.

The coefficients K1, K2, and K3 are set such that the magnitudes thereof satisfy K1 <K2 <K3. That is, speed control to accelerate with low acceleration is performed when the AC power supply 12 is (1) single-phase 100 V band, and (2) speed control is accelerated with medium acceleration when single-phase 200 V band. (3) In the case of the three-phase 200 V band, speed control is performed to accelerate at high acceleration.
This is because the amount of current flowing from the AC power supply 12 increases and the load on the AC power supply 12 increases as the acceleration increases as the sewing machine motor 11 is accelerated.
That is, the AC power supply 12 can flow a large current as the AC voltage becomes higher, and can flow a larger current as the number of phases increases.

  Therefore, the motor drive circuit 52 has the smallest current that can be supplied (1) suppresses the acceleration in the single-phase 100 V band, and the largest current that can be supplied (3) the acceleration in the three-phase 200 V band. By increasing the size, the sewing machine motor 11 is controlled so that the generation of the load can be reduced regardless of the AC power supply 12 in any case.

[Function of power supply circuit of sewing machine motor]
When using the power supply circuit 10 of the sewing machine motor, the manual switch 43 is switched according to the band of the AC voltage of the AC power supply 12 first. That is, the operator of the sewing machine determines which of double-voltage rectification and full-wave rectification is to be performed, and the switching operation of the manual switch 43 is performed.
As a result, when the AC power supply 12 is (1) single phase 100 V band, voltage doubler rectification is performed, and when the AC power supply 12 is (2) single phase 200 V band or (3) three phase 200 V band, all Wave rectification is performed.

The voltage detection unit 44 performs voltage detection. When the AC power supply 12 has (1) single-phase 100 V band voltage detection as shown in FIG. 2, (2) single-phase 200 V band Voltage detection is performed with a waveform such as 3; (3) in the case of a three-phase 200 V band, voltage detection is performed with a waveform as shown in FIG.
From the voltage detection from the voltage detection unit 44, the determination unit 53 calculates the minimum potential Vl, the minimum potential time Tl, the maximum potential Vh, and the maximum potential time Th, and compares each with a threshold value. 1) A single-phase 100 V band, (2) a single-phase 200 V band, or (3) a three-phase 200 V band is specified and input to the motor drive circuit 52.

  The motor drive circuit 52 selects the coefficients K1 to K3 in accordance with the determination result of the determination unit 53, and executes the speed control of the sewing machine motor 11 with the acceleration multiplied by the coefficients.

[Technical effect of the invention]
As described above, the power supply circuit 10 of the sewing machine motor includes the first diode bridge 20 connected to the AC power supply 12 and the two capacitors 41 and 42 connected to the output parts 23 and 24 of the first diode bridge 20. , A manual switch 43 as a switching unit for switching the middle of the two capacitors 41 and 42 and the 22 input of the first diode bridge 20 to a short circuit state and a disconnection state, a second diode bridge 30, and a second The duration (minimum potential time Tl) of the minimum potential Vl in the continuous change of the detection voltage of the voltage detection section 44 and the voltage detection section 44 for detecting the voltage of the two output sections 33 and 34 of the diode bridge 30 A determination unit 53 that determines whether the manual switch 43 is in the voltage doubler rectification state or the full-wave rectification state from the minimum potential time Tl, and the rectification state obtained by the determination unit 53 And a motor drive circuit 52 serving as a motor control unit that performs output control of Luo sewing machine motor.

Therefore, it is possible to identify which band of the AC voltage of AC power supply 12 is, and motor drive circuit 52 is configured to allow sewing machine motor 11 to reduce load on AC power supply 12 according to the band of AC voltage. Can be controlled.
Further, even when the power supply is supplied to the sewing machine motor 11 by connecting to the AC power supply of a facility such as a sewing factory using a plurality of sewing machines, generation of voltage drop (flicker) of the power supply is reduced. Thus, good sewing can be performed on a plurality of sewing machines.

Further, determination unit 53 determines the duration (maximum potential time Th) of maximum potential Vh in the continuous change of the detection voltage of voltage detection section 44, and determines the number of phases of AC power supply 12 from the maximum potential time Th. Since the motor drive circuit 52 controls the output of the sewing machine motor 11 based on the number of phases of the AC power supply 12 determined by the determination unit 53, the sewing machine motor 11 is configured to reduce the load on the AC power supply 12 according to the number of phases. Can be controlled.
Therefore, even under the environment where a plurality of sewing machines are used, it is possible to further reduce the occurrence of voltage drop (flicker) of the power supply and to perform more favorable sewing.

  In addition, since the determination unit 53 can identify which band of the AC voltage of the AC power supply 12 is, the AC power supply can be obtained by determining the cycle of repeating the continuous waveform from the detection voltage of the voltage detection unit 44. It is also possible to determine 12 power supply frequencies.

[Others]
In addition, although the determination unit 53 obtains the type of the AC voltage band of the AC power supply 12, it is also possible to obtain a more detailed AC voltage of the AC power supply in the band instead of the AC voltage band.
That is, the determination unit 53 obtains the time-series change of the detection voltage from the voltage detection unit 44 and obtains the maximum potential Vh, but the value of the maximum potential Vh is correlated with the value of the AC voltage of the AC power supply. Since there is a storage unit storing a table recording the correspondence between the value of the maximum potential Vh and the value of the AC power supply voltage in the determination unit 53, the value of the AC voltage of the AC power supply can be obtained from the value of the maximum potential Vh. It is possible to ask for From the value of the maximum potential Vh, the value of the AC voltage of the AC power supply can be determined with an accuracy of approximately 1 [V]. For example, (1) the single-phase 100 V band has an AC voltage value of 100 to 120 V Although it is within the range, this value can be specified by 1 [V] unit. The same applies to the other bands (2) and (3).

DESCRIPTION OF SYMBOLS 10 Power supply circuit 11 Sewing machine motor 12 AC power supply 20 1st diode bridge 21,22 Input part 23,24 Output part 25-28 Diode 30 2nd diode bridge 31,32 Input part 33,34 Output part 35-38 Diode 41 , 42 Condenser 43 Manual switch (switching unit)
44 Voltage detection unit 45, 46 Resistor 51 Three-phase rectification circuit 52 Motor drive circuit (motor control unit)
53 Judgment part
Th maximum potential time (duration of maximum potential)
Tl Minimum potential time (duration of minimum potential)
Vh maximum potential
Vl minimum potential

Claims (2)

A first diode bridge with two inputs connected to the alternating current source and two outputs connected to the load;
Two capacitors connected in series between the two outputs of the first diode bridge;
A switching unit that switches between the short circuit state and the disconnected state between the middle of the two capacitors and one input of the first diode bridge;
A second diode bridge comprising two inputs connected in parallel to the first diode bridge to the alternating current source,
A voltage detection unit that detects voltages of two outputs of the second diode bridge;
A determination unit which determines the duration of the minimum potential in the continuous change of the detection voltage of the voltage detection unit, and determines from the duration of the minimum potential whether the switching unit is in the voltage doubler rectification state or the full wave rectification state;
And a motor control unit that performs output control of the sewing machine motor from the rectified state determined by the determination unit. The determination unit determines the duration of the maximum potential in the continuous change of the detection voltage of the voltage detection unit, and determines the number of phases of the AC power supply from the duration of the maximum potential.
The power supply circuit of a sewing machine motor according to claim 1, wherein the motor control unit performs output control of the sewing machine motor from the number of phases of the AC power supply determined by the determination unit.

Images