JP2005045936A - Dc power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC power supply capable of operating an external equipment such as an electromagnetic brake in a short time, where the time from when a power supply is turned off till a brake current is turned off is short, with variation in the time being small. <P>SOLUTION: A DC power supply 2 supplies a DC current I which is based on an inputted AC power to an external equipment 3. It comprises a fullwave rectification circuit 150 for fullwave rectifying an AC power, a voltage comparison circuit 200a which compares an output voltage of the fullwave rectification circuit 150 to a reference voltage, a charging/discharging circuit 300a which repeats charging/discharging according to the comparison result of the voltage comparison circuit 200a, and a field effect transistor 18 in which the charging/discharging circuit 300a is connected between a gate and a source. Turning on/off of the field effect transistor 18 energizes/cuts off the DC current I. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a DC power supply device such as an electromagnetic brake DC power supply device that is attached to a motor and supplies a DC current based on input AC power to an electromagnetic brake.

  FIG. 9 is a block diagram showing a configuration example of a conventional electromagnetic brake device (first conventional example). In this electromagnetic brake device, a motor 10 with a brake has a conventional DC power supply device 20 for an electromagnetic brake, an electromagnetic brake 3 and a motor 4. Terminals R, S, and T of a three-phase AC power source (not shown) are connected to terminals U, V, and W of the motor 4, respectively. Between the wiring between the terminal R and the terminal U and the wiring between the terminal S and the terminal V, the electromagnetic contactor 43, the stop push button switch 42, the start push button switch 41, and the auxiliary contact 43b of the electromagnetic contactor 43 are arranged in parallel. The circuit is connected. A main contact 43a for opening / closing a circuit of the electromagnetic contactor 43 is provided on the wiring between the terminal R and the terminal U, the wiring between the terminal S and the terminal V, and the wiring between the terminal T and the terminal W, respectively.

  The electromagnetic brake DC power supply device 20 is connected to the terminal U and the terminal V and supplied with power.

  FIG. 10 is a circuit diagram showing a configuration example of this conventional electromagnetic brake DC power supply device 20. The electromagnetic brake DC power supply device 20 includes input terminals 202a and 202b, output terminals 202c and 202d, surge absorbing elements 211 and 212, and diodes 213 and 214.

  Next, the operation will be described. When the start pushbutton switch 41 is pressed, the coil of the electromagnetic contactor 43 is excited, the main contact 43a is closed, current flows to the motor 4, and the current rectified by the electromagnetic brake DC power supply 20 is electromagnetically The electromagnetic brake 3 is excited to release the braking. When the coil of the electromagnetic contactor 43 is energized, the auxiliary contact 43b of the electromagnetic contactor 43 is closed, and even if the start push button switch 41 is opened, the coil of the electromagnetic contactor 43 continues to be excited and the motor 4 rotates. to continue. When the stop pushbutton switch 42 is pressed, the coil of the electromagnetic contactor 43 is de-energized, and the electromagnetic brake 3, the electromagnetic brake DC power supply device 20, and the motor 4 are cut off from the AC power supply.

  In the first conventional example, the residual voltage generated at the terminals U, V, and W of the motor 4 until the motor 4 stops is applied to the DC power supply device 20 for electromagnetic brake and rectified, The time until the electromagnetic brake 3 operates becomes longer, and the stop position shift of the motor with brake 10 occurs. For example, in the speed reducer or electric cylinder to which the motor 10 with brake is attached, when the load with large inertia is stopped, the position shifts, and when the descending operation is stopped by the lifting operation, the electromagnetic brake 3 is activated. The time required for the operation of the electromagnetic brake 3 becomes longer when the coasting distance becomes longer, the coasting distance becomes longer, the vehicle escapes from the original stop position, and the ascending operation is stopped by the elevating operation. There are problems such as falling and not reaching the original stop position.

  FIG. 11 is a block diagram showing a configuration example of a conventional electromagnetic brake device (second conventional example) in which the operation for operating the electromagnetic brake is accelerated. In FIG. 11, the same parts as those in FIG. In the second conventional example, an electromagnetic contactor 44 connected in parallel to the electromagnetic contactor 43 and its contact 44a are added to the first conventional example. The electromagnetic brake DC power supply device 20 is connected to the terminal R and the terminal S via the contact 44a, and is supplied with power.

  Next, the operation will be described. When the start push button switch 41 is pressed, the coils of the electromagnetic contactors 43 and 44 are excited, the contacts 43a and 44a are closed, and a current flows through the motor 4 and is rectified by the DC power supply device 20 for the electromagnetic brake. The electric current flows through the electromagnetic brake 3, and the electromagnetic brake 3 is excited to release its braking. When the coil of the electromagnetic contactor 43 is excited, the auxiliary contact 43b is closed and the coil of the electromagnetic contactors 43 and 44 continues to be excited and the motor 4 continues to rotate even when the start push button switch 41 is opened. When the stop pushbutton switch 42 is pressed, the coils of the electromagnetic contactors 43 and 44 are de-energized, and the electromagnetic brake 3, the electromagnetic brake DC power supply device 20 and the motor 4 are disconnected from the AC power supply.

  In the second conventional example, the residual voltage generated at the terminals U, V, and W of the motor 4 is not applied to the electromagnetic brake DC power supply device 20 until the motor 4 stops. However, since the circulating current continues to flow through the diode 214 and the electromagnetic brake 3 in the DC power supply device 20 for the electromagnetic brake, the time until the electromagnetic brake 3 operates is shorter than that of the first conventional example. 1 The problem with the prior art cannot be completely solved. Therefore, it has been desired to develop a DC power supply device for an electromagnetic brake that can shorten the time until the electromagnetic brake operates.

  FIG. 12 is a block diagram showing a configuration example of a conventional DC power supply device for electromagnetic brake (third conventional example) developed to operate the electromagnetic brake at high speed. In FIG. 12, the same parts as those in FIG. The DC power supply device 20A for electromagnetic brakes of the third conventional example replaces the DC power supply device 20 for electromagnetic brakes (FIG. 11), and includes input terminals 202a and 202b, output terminals 202c and 202d, Surge absorbing elements 211, 212, diodes 213, 214, 215, 216, FET (Field Effect Transistor) 218, half-wave rectifier circuit 221, comparator power supply circuit 222, gate drive power supply circuit 223, input The power interruption detection charging / discharging circuit 224, a comparator 225, and a gate driving circuit 226 are included.

Half-wave rectifier circuit 221 rectifies the AC voltage V _a that is input, and outputs a brake current I. Comparing power supply for circuit 222, resistor, is composed of a Zener diode and a capacitor, the voltage after the AC voltage V _a half-wave rectifier circuit 221 and the diode 215 and 216 and full wave rectified, comparing power supply for circuit 222 The DC voltage is supplied to the comparator 225 by the Zener diode and the capacitor. The gate drive power supply circuit 223 includes a resistor, a Zener diode, and a capacitor. Similarly, the voltage after full-wave rectification is stepped down by the resistor in the gate drive power supply circuit 223, and the Zener diode and the capacitor A DC voltage is supplied to the gate drive circuit 226 of the FET 218.

Input power-off detecting charge and discharge circuit 224 has two charging and discharging circuit starts simultaneously charging a closing of the input power source, after the completion of charging, the AC voltage V _a is input power is cut off drops Sometimes after a certain time, the levels of the two output voltages E _a and E _b are reversed. The comparator 225 compares the levels of the two output voltages E _a and E _b from the input power cutoff detection charging / discharging circuit 224, and outputs _a gate cutoff signal at the timing when the levels of E _a and E _b are inverted. Output to the gate drive circuit 226. When the gate cut-off signal is input, the gate drive circuit 226 clamps the gate voltage supplied from the gate drive power supply circuit 223 to 0 V, turns off the FET 218, and cuts off the brake current I.

  In the DC power supply 20A for electromagnetic brake of the third conventional example, a plurality of power supply circuits are necessary, so that there are many portions that generate heat, and the number of parts is large and the outer shape is large, so that they are stored in the motor terminal box. For this purpose, a very large motor terminal box is required. In particular, since a large motor terminal box cannot be attached to a small motor, the electromagnetic brake DC power supply 20A must be housed in the control panel, not in the motor terminal box. Therefore, it is necessary to provide wiring for the brake between the mounting space in the control panel or between the motor terminal box and the control panel, which raises a problem that costs increase. Therefore, it has been desired to develop a small DC power supply for an electromagnetic brake that can be stored in a motor terminal box of a small motor.

  FIG. 13 shows a DC power supply device for electromagnetic brakes (fourth conventional example) proposed by the present applicant in Japanese Patent Application No. 2002-124886 in order to solve the problems of the first to third conventional examples. It is a circuit diagram which shows the example of a structure. This DC power supply device for electromagnetic brake 20B replaces the DC power supply device for electromagnetic brake 20 of the electromagnetic brake device (FIG. 11), and includes input terminals 202a and 202b, output terminals 202c and 202d, a surge absorbing element 121, 122, half-wave rectifier circuit 100, voltage comparison circuit 200, charge / discharge circuit 300, and FET 128.

  Half-wave rectifier circuit 100 includes diodes 123 and 124. The diode 124 is a flywheel diode. The voltage comparison circuit 200 includes a transistor 127, a Zener diode 131, and resistors 132, 133, and 134. The charge / discharge circuit 300 includes a diode 126, a capacitor 130, and a resistor 135.

  The operation of the electromagnetic brake DC power supply device 20B having such a configuration will be described below with reference to the timing chart of FIG.

  When the start pushbutton switch 41 (FIG. 11) is pressed, the coils of the electromagnetic contactors 43 and 44 are excited, the contacts 43a and 44a are closed, current flows to the motor 4, and the DC power supply device 20B for electromagnetic brakes. The electric current rectified in (5) flows into the electromagnetic brake 3, and the electromagnetic brake 3 is excited to release its braking. When the coil of the electromagnetic contactor 43 is energized, the auxiliary contact 43b of the electromagnetic contactor 43 is closed and the coil of the electromagnetic contactors 43 and 44 continues to be excited even when the start push button switch 41 is opened. Continue to rotate.

Input terminal 202a of the electromagnetic brake DC power supply apparatus 20B, the inter-202b is an AC voltage V _a (FIG. 13) is inputted, the half-wave rectifying circuit 100, the AC voltage V _a by a diode 123 and half-wave rectification, and it outputs the rectified voltage E _a. The voltage E _a output from the half-wave rectifier circuit 100 is applied to both ends of the resistors 132 and 133 connected in series in the voltage comparison circuit 200. The voltage E _a is divided by the resistors 132 and 133. When the divided voltage becomes higher than the Zener voltage E _z of the Zener diode 131 and the following condition (1) is satisfied, the transistor 127 is turned on and the voltage E _a is applied to the collectors thereof by resistors 132 and 133. A voltage E _{b that} is _divided and clipped by the Zener voltage E _z is output (t _a (a) in FIG. 14A).

E _a × {R ₃₃ / (R ₃₂ + R ₃₃ )} ≧ E _z + V _BE (1)
However, R ₃₂ : Resistance value of the resistor 132 R ₃₃ : Resistance value of the resistor 133
V _BE: voltage E _a which is output from the base voltage half-wave rectifier circuit 100 during conduction of the transistor 127 is equal to or satisfy the condition (2) below, a transistor 127 is cut off (Fig. 14 (a) T _b (a)).

E _a × {R ₃₃ / (R ₃₂ + R ₃₃ )} <E _z + V _BE (2)
The voltage output from the voltage comparison circuit 200 is supplied to the charge / discharge circuit 300, and a current flows through the resistor 135 and the capacitor 130 through the diode 126. Then, the capacitor 130 is charged, and the voltage E _c shown in (3) below is output from the charge / discharge circuit 300 and applied to the gate of the FET 128 (t _a (a) in FIG. 14A).

E _c = E _b −V _f (3)
However, V _f : forward voltage of the diode 126 On the other hand, when the diode 126 becomes non-conductive, the charge charged in the capacitor 130 is discharged through the resistor 135, and the voltage E _c applied to the gate of the FET 128 decreases ( T _b (a) in FIG.

When the voltage E _a output from the half-wave rectifier circuit 100 increases again to satisfy the condition (1), the voltage E _c applied to the gate of the FET 128 is again shown in (3). It becomes size.

Such an operation period (t _{a (a} in FIG. _{14 (a)), t b} (a)) in, the voltage E _c applied to the gate of the FET 128, the threshold voltage E _t of the gate-source voltage of FET 128 Since it exceeds, FET 128 continues to conduct.

In this state, when the stop push button switch 42 is pressed, the coils of the electromagnetic contactors 43 and 44 are de-energized and the contacts 43a and 44a are opened, and the motor 4, the electromagnetic brake DC power supply 20B and the electromagnetic The brake 3 is disconnected from the AC power source. In this example, the electromagnetic contactor 43 is opened at the beginning of the cycle T ₅ in FIG. 14A and is disconnected from the three-phase AC power source.

When the DC power supply device 20B for the electromagnetic brake is disconnected from the AC power source, the input terminal 202a of the electromagnetic brake DC power supply apparatus 20B, there is no AC voltage V _a between 202b, also eliminates the voltage E _a, transistor 127 is cut off . As a result, when the voltage E _c applied to the gate of the FET 128 continues to decrease and becomes lower than the threshold voltage E _t of the gate-source voltage of the FET 128, the FET 128 becomes non-conductive and is applied to the electromagnetic brake 3 through the diode 123 or the diode 124. interrupting the braking current I flowing (t _e in FIG. 14 (a) (a)) .

  Thus, in the fourth conventional example, when the input of the AC voltage to the DC power supply device 20B for electromagnetic brake is cut off, the brake current I flowing through the diode 123 or 124 of the half-wave rectifier circuit 100 is cut off by the FET 128. . Therefore, the electromagnetic brake 3 can be operated in a shorter time compared to the case of using another conventional electromagnetic power supply for an electromagnetic brake composed only of a half-wave rectifier circuit.

  Further, in the brake-equipped motor in which the electromagnetic brake DC power supply device 20B, the electromagnetic brake 3 and the motor 4 of the fourth conventional example are combined, the electromagnetic brake DC power supply device 20B and the motor 4 are connected by the same electromagnetic contactor 43. Even if the motor is cut off, the brake current I is cut off when the residual voltage of the motor 4 becomes lower than the reference voltage. Therefore, the electromagnetic brake 3 can be operated in a shorter time than the conventional motor 10 with brake.

  Further, since the decrease in the output voltage of the half-wave rectifier circuit 100 is detected and the brake current I is cut off by the FET 128, the control system using the brake electromagnetic contactor as described in the second conventional example and the brake Without adding wiring, the motor with brake can be stopped faster than the first conventional example. And the problem of the position shift in the reduction gear or electric cylinder which attached the motor with a brake can be solved.

  Further, the capacitor 130 connected between the gate and the source of the FET 128 is charged when the half-wave rectified voltage is higher than the reference voltage in the voltage comparison circuit 200, and when the voltage is low, the resistor 135 connected in parallel is charged. The voltage across the capacitor 130 is input to the FET 128 as a gate-source voltage. As a result, when the half-wave rectified voltage becomes higher than the reference voltage every cycle, the FET 128 continues to conduct, and when the half-wave rectified voltage is lower than the reference voltage, the voltage across the capacitor 130 is The FET 128 is cut off below the gate voltage threshold of the FET 128. Therefore, the power supply circuit for driving the FET as in the third conventional example is unnecessary.

  As described above, the DC power supply device 20B for the electromagnetic brake of the fourth conventional example does not require the comparator DC power supply circuit and the gate drive DC power supply circuit as compared with the third conventional example. A small configuration can be realized with a small number of points. Therefore, it is possible to store in the motor terminal box of a small motor, and it is necessary to store the DC power supply for electromagnetic brake in the control panel and to perform wiring with the motor terminal box. The problem can be solved.

  Furthermore, by setting the Zener voltage of the Zener diode 131 used for this reference voltage to be equal to or lower than the rated voltage between the gate and source of the FET 128, the Zener diode 131 is added to the setting of the reference voltage of the voltage comparison circuit 200 and the gate of the FET 128. It plays both applications with maximum voltage regulation.

Patent Document 1 discloses a negatively operated electromagnetic brake that can prevent the inflow of the generated current of the AC motor at an early point in time and accelerate the braking stop of the AC motor.
Japanese Patent No. 2984897

  In the DC power supply device 20B for the electromagnetic brake of the fourth conventional example, as described above, the electromagnetic brake 3 is operated in a short time by turning off the brake current in a shorter time than the electromagnetic brake devices of the first and second conventional examples. I can do it. Further, it can be made smaller than the DC power supply for electromagnetic brakes of the third conventional example. However, depending on other types of AC brakes and applications (such as when the demand for stopping accuracy is high), the electromagnetic brake 3 can be operated in a short time by turning off the brake current in a short time. May not be possible, and further time reduction is required.

There is also a problem that there is a large variation in time from when the power is turned off to when the brake current is turned off. For example, the timing chart shown in FIG. 14 (a) described above is when interruption of the AC power supply is a time of discharge of the capacitor 130, and indicates when the voltage E _c applied to the gate of the FET128 is minimum, 14 the timing chart of (b), at the time of interruption of the AC power supply, a charging of the capacitor 130, which indicates when the voltage E _c applied to the gate of the FET128 is maximum. Therefore, the respective times from the interruption of the AC power supply to the turning off of the brake current are t _e (a) and time t _e (b), and a large variation BA1 occurs. For this reason, there is a problem that the timing at which the electromagnetic brake 3 operates varies and it is difficult to perform highly accurate positioning.

  The present invention has been made in view of the above-described circumstances, and the time from when the power is turned off until the brake current is turned off is short, and the time variation is small. It is an object of the present invention to provide a DC power supply device that can operate a device in a short time.

  According to a first aspect of the present invention, there is provided a direct current power supply device for supplying a direct current based on input alternating current power to an external device, a full wave rectification circuit for full wave rectification of the alternating current power, A voltage comparison circuit that compares an output voltage with a reference voltage, a charge / discharge circuit that repeats charging / discharging according to a comparison result in the voltage comparison circuit, and the charge / discharge circuit are connected between the gate and the source And a field effect transistor, wherein the direct current is turned on / off by turning on / off the field effect transistor.

  In this DC power supply device, a DC current based on the input AC power is supplied to an external device. The AC power input by the full-wave rectifier circuit is full-wave rectified, and the voltage comparison circuit compares the output voltage of the full-wave rectifier circuit with a reference voltage. The charge / discharge circuit repeats charging / discharging according to the comparison result in the voltage comparison circuit, and the charge / discharge circuit is connected between the gate and source of the field effect transistor. The field effect transistor energizes / cuts off a direct current based on the input alternating current power by turning on / off the field effect transistor.

  As a result, the charge / discharge circuit can be charged more frequently than when the output voltage of the half-wave rectifier circuit is compared with the reference voltage, so the time constant of the charge / discharge circuit can be set smaller, and the power supply It is possible to realize a direct current power supply device that can operate an external device such as an electromagnetic brake in a short time with a short time from when the brake current is turned off until the brake current is turned off.

  The direct current power supply device according to the second aspect of the present invention further includes a switching circuit for switching energization / cutoff of the direct current from the outside.

  In this DC power supply device, since the switching circuit switches the energization / cutoff of the DC current based on the input AC power from the outside, if necessary, the switching circuit is used so that the brake current is turned off after the power is turned off. It is possible to realize a DC power supply device that can further shorten the time until the power is turned off, further reduce the variation in the time, and operate external devices such as an electromagnetic brake in a shorter time. .

  A DC power supply according to a third aspect of the present invention includes a half-wave rectifier circuit that half-rectifies input AC power, a voltage comparison circuit that compares an output voltage of the half-wave rectifier circuit with a reference voltage, and the voltage comparison circuit A charge / discharge circuit that repeats charging / discharging in accordance with the comparison result in the above, and a field effect transistor connected between the gate and source of the charge / discharge circuit, and direct current based on the AC power to an external device A DC power supply apparatus configured to supply and cut off the DC current by turning on / off the field effect transistor, and includes a switching circuit for switching on / off of the DC current from the outside. It is characterized by that.

  In this DC power supply device, the half-wave rectifier circuit half-rectifies the input AC power, the voltage comparison circuit compares the output voltage of the half-wave rectifier circuit with the reference voltage, and the charge / discharge circuit compares the voltage. Charging / discharging is repeated according to the comparison result in the circuit. The field effect transistor has a charge / discharge circuit connected between its gate and source, supplies a DC current based on AC power to an external device, and turns on / off the DC current by turning on / off the field effect transistor. . The switching circuit switches energization / cutoff of the DC current from the outside.

  This makes it possible to further shorten the time from when the power is turned off until the brake current is turned off by using a switching circuit, if necessary, and to further reduce the variation in time. A DC power supply device that can operate external devices such as brakes in a shorter time can be realized.

  According to the DC power supply device according to the first aspect of the invention, the charge / discharge circuit can be charged more frequently than when the output voltage of the half-wave rectifier circuit is compared with the reference voltage. DC that can be set small, the time from when the power is turned off to when the brake current is turned off is short, and the time variation is small, and external devices such as electromagnetic brakes can be operated in a short time A power supply device can be realized.

  According to the DC power supply device according to the second invention, if necessary, the time from when the power is turned off to when the brake current is turned off can be further shortened, and the variation in the time can be further reduced. It is possible to realize a DC power supply device that can operate an external device such as an electromagnetic brake in a shorter time.

  According to the DC power supply device according to the third invention, if necessary, the time from when the power is turned off to when the brake current is turned off can be further shortened, and the variation in the time can be further reduced. It is possible to realize a DC power supply device that can operate an external device such as an electromagnetic brake in a shorter time.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of an electromagnetic brake device including an electromagnetic brake DC power supply device according to a first embodiment of a DC power supply device according to the present invention. In this electromagnetic brake device, the motor 1 with brake includes a DC power supply device 2 for electromagnetic brake, an electromagnetic brake 3 and a motor 4. Terminals R, S, and T of a three-phase AC power source (not shown) are connected to terminals U, V, and W of the motor 4, respectively. An electromagnetic contactor 43, a stop push button switch 42, and a start push button switch 41 are connected in series between the wiring between the terminal R and the terminal U and the wiring between the terminal S and the terminal V. The magnetic contactor 43 is connected in parallel.

  An auxiliary contact 43 b of an electromagnetic contactor 43 is connected in parallel to the start push button switch 41. A contact 43a for opening / closing a circuit of the electromagnetic contactor 43 is provided on the wiring between the terminal R and the terminal U, the wiring between the terminal S and the terminal V, and the wiring between the terminal T and the terminal W, respectively.

  The DC power supply device 2 for electromagnetic brake is connected to a terminal R and a terminal S via a contact 44a of an electromagnetic contactor 44, and is supplied with power.

  FIG. 2 is a circuit diagram showing a configuration example of the DC power supply device 2 for electromagnetic brake. This DC power supply device 2 for electromagnetic brake includes a diode 14A having a surge absorbing element 11 connected between input terminals 2a and 2b, an anode connected to the input terminal 2a, and a diode 13A having an anode connected to the input terminal 2b. Are connected by each cathode. A diode 14 having a cathode connected to the input terminal 2a and a diode 13 having a cathode connected to the input terminal 2b are connected by respective anodes. Surge absorption elements 11A and 12A are connected in parallel to the diodes 13 and 14, respectively. It is connected.

  Resistors 22 and 23 are connected in series between the cathodes of the diodes 13 A and 14 A and the anode of the diode 13, and the connection node of the resistors 22 and 23 is connected to the emitter of the PNP transistor 17. A resistor 24 is connected between the emitter and base of the transistor 17, and a cathode of a Zener diode 21 whose anode is connected to the anode of the diode 13 is further connected to the base.

  The collector of the transistor 17 is connected to the anode of the diode 16, and the cathode of the diode 16 is connected to one terminal of a resistor 25 whose other terminal is connected to the anode of the diode 13.

  The cathode of the diode 16 is connected to one terminal of a capacitor 19 whose other terminal is connected to the anode of the diode 13, and is further connected to the gate of an N-channel field effect transistor (FET) 18. The source of the FET 18 is connected to the anode of the diode 13, and the drain thereof is connected to the output terminal 2d. The output terminal 2c is connected to the input terminal 2a, and the surge absorbing element 12 is connected between the output terminals 2c and 2d.

  The diodes 13 and 14 constitute a half-wave rectifier circuit 100a, and the diodes 13, 14, 13A and 14A constitute a full-wave rectifier circuit 150.

  The transistor 17, the Zener diode 21, and the resistors 22, 23, and 24 constitute a voltage comparison circuit 200a.

  The diode 16, the capacitor 19, and the resistor 25 constitute a charge / discharge circuit 300a.

  The operation of the DC power supply device 2 for an electromagnetic brake having such a configuration will be described below with reference to the timing chart of FIG.

  When the start push button switch 41 (FIG. 1) is pressed, the coils of the electromagnetic contactors 43 and 44 are excited, the contacts 43a and 44a are closed, current flows to the motor 4, and the DC power supply device 2 for electromagnetic brakes. The electric current rectified in (5) flows into the electromagnetic brake 3, and the electromagnetic brake 3 is excited to release its braking. When the coil of the electromagnetic contactor 43 is energized, the auxiliary contact 43b of the electromagnetic contactor 43 is closed and the coil of the electromagnetic contactors 43 and 44 continues to be excited even when the start push button switch 41 is opened. Continue to rotate.

Input terminal 2a of the electromagnetic brake DC power supply apparatus 2, when the inter-2b AC voltage V _a (FIG. 2) is input, a half-wave rectifier circuit 100a is the AC voltage V _a half-wave rectified, the rectified voltage Is output to the electromagnetic brake 3 through the output terminals 2c and 2d (FIG. 2) of the DC power supply device 2 for the electromagnetic brake.

Moreover, the full-wave rectifier circuit 150, an AC voltage V _a that is input to full-wave rectification, and outputs the rectified voltage. Full wave voltage E _a which is output from the rectifier circuit 150 is applied across the voltage comparator circuit 200a connected in series with the resistance in the 22 and 23. The voltage E _a is divided by the resistors 22 and 23. When the divided voltage becomes higher than the Zener voltage E _z of the Zener diode 21 and satisfies the following condition (4), the transistor 17 is turned on and the voltage E _a is applied to the collectors of the resistors 22 and 23. A voltage E _{b that} is _divided and clipped by the Zener voltage E _z is output (t _a (c) in FIG. 3A).

E _a × {R ₂₃ / (R ₂₂ + R ₂₃ )} ≧ E _z + V _BE (4)
However, R ₂₂ : Resistance value of the resistor 22 R ₂₃ : Resistance value of the resistor 23
V _BE : Base voltage when transistor 17 is conductive When the voltage E _a output from the full-wave rectifier circuit 150 satisfies the following condition (5), the transistor 17 is turned off (see FIG. 3A). T _b (c)).

E _a × {R ₂₃ / (R ₂₂ + R ₂₃ )} <E _z + V _BE (5)
The voltage output from the voltage comparison circuit 200a is supplied to the charge / discharge circuit 300a, and a current flows through the resistor 16 and the capacitor 19 through the diode 16. Then, the capacitor 19 is charged, and the voltage E _c shown in the following (6) is output from the charge / discharge circuit 300a and applied to the gate of the FET 18 (t _a (c) in FIG. 3A).

E _c = E _b −V _f (6)
However, V _f : forward voltage of the diode 16 On the other hand, when the diode 16 becomes non-conductive, the charge charged in the capacitor 19 is discharged through the resistor 25 and the voltage E _c applied to the gate of the FET 18 decreases ( T _b (c) in FIG.

When the voltage E _a output from the full-wave rectifier circuit 150 is increased again to satisfy the condition (4), the voltage E _c applied to the gate of the FET 18 is again shown in (6). It becomes size.

Such an operation period (t _a (c in FIG. _{3 (a)), t b} (c)) in, the voltage E _c applied to the gate of the FET 18, the threshold voltage E _t of the gate-source voltage of FET 18 Since it exceeds, FET 18 continues to conduct. At this time, the minimum value of the voltage E _c applied to the gate of the FET 18 is E _t2 (FIG. 3A). Similarly, the minimum value of the voltage E _c applied to the gate of the FET 128 when the FET 128 (FIG. 13) of the fourth conventional example continues to conduct is E _t1 (FIG. 14 (a)).

If the same product is used for each of the FET 18 and the FET 128 of the electromagnetic brake DC power supply device 2 of the present embodiment and the electromagnetic brake DC power supply device 20B of the fourth conventional example, the threshold values of the gate and source voltages of both are the same. E _t, and the minimum value of the output voltage E _c applied to the gate of each of when the FET18 and FET128 continues to conduct, respectively E _t2 and E _t1 becomes, in order to continue to reliably conduct the FET18 and FET128 the threshold Since it suffices if it is larger than E _t by a certain value, E _t2 and E _t1 can be set to the same value.

Further, charge and discharge frequency per frequency one period of the AC power supply V _a in the charge-discharge circuit 300a (FIG. 3) is twice the number of times of charge and discharge of the fourth conventional example of the charging and discharging circuit 300 (FIG. 14), more Can be charged and discharged frequently.

Therefore, by setting E _t2 and E _t1 to the same value in the above, the time constant τ2 of the charge / discharge circuit 300a (FIG. 3A; the capacitance value of the capacitor 19 × the resistance value of the resistor 25) is 4. It can be set smaller than the time constant τ1 of the conventional charge / discharge circuit 300 (FIG. 14A; capacitance value of capacitor 130 × resistance value of resistor 135).

When the stop push button switch 42 (FIG. 1) is pressed in such a state, the coils of the electromagnetic contactors 43 and 44 are de-energized and the contacts 43a and 44a are opened, and the motor 4 and the DC power source for the electromagnetic brake are opened. The device 2 and the electromagnetic brake 3 are disconnected from the AC power source. In the present embodiment, the magnetic contactors 43 and 44 are opened at the beginning of the cycle T ₅ in FIG. 3A and are disconnected from the three-phase AC power source.

When the DC electromagnetic brake power device 2 is disconnected from the AC power source, the input terminal 2a of the DC electromagnetic brake power device 2, there is no AC voltage V _a between 2b eliminates also the output voltage E _a of the full-wave rectifier circuit 150 The transistor 17 is cut off. As a result, continues to drop the voltage E _c to be applied to the gate of FET 18, when it becomes lower than the threshold voltage E _t of the gate-source voltage of FET 18, FET 18 becomes non-conductive, the electromagnetic brake 3 through a half-wave rectifier circuit 100a The flowing brake current I is cut off ( _te (c) in FIG. 3A).

In the DC power supply device 2 for electromagnetic brake according to the present embodiment, the time from when the AC power is cut off until the brake current I is cut off is minimized because of the output voltage E _c of the charge / discharge circuit 300a. Is E _t2 in the discharged state, and the AC power supply is turned off. Since the shut-off AC power at that time, the output voltage E _c (= E _t2) is below the threshold voltage E _t of the gate-source voltage of FET18 by the discharge, until the time the brake current I is interrupted t _e (c) (FIG. 3A).

From the AC power source is cut off, the time until the braking current I is cut off is maximized, the output voltage E _c of the charge and discharge circuit 300a is in a fully charged state, is when the AC power is turned off. Since the shut-off AC power at that time, the output voltage E _c (full charge) discharge becomes below the threshold voltage E _t of the gate-source voltage of the FET 18, time until the brake current I is interrupted t _e (d) (FIG. 3B).

In the DC power supply device 20B for the electromagnetic brake of the fourth conventional example, the time from when the AC power is cut off until the brake current I is cut off is minimized by the output voltage E _c of the charge / discharge circuit 300. This is a case where the AC power supply is turned off at E _t1 in the discharge state. Since the shut-off AC power at that time, the output voltage E _c (= E _t1) becomes below the threshold voltage E _t of the gate-source voltage of the FET128 by the discharge, until the time the brake current I is interrupted t _e (a) (FIG. 14A).

From the AC power supply is cut off, the time until the braking current I is cut off is maximized, the output voltage E _c of the charge and discharge circuit 300 is in a fully charged state, is when the AC power is turned off. Since the shut-off AC power at that time, the output voltage E _c (full charge) discharge becomes below the threshold voltage E _t of the gate-source voltage of FET 128, the time until the braking current I is interrupted t _e (b) (FIG. 14B).

Here, since the time constant τ2 (FIG. 3A) is smaller than the time constant τ1 (FIG. 14A), the brake power I is cut off after the AC power supply of the DC power supply device 2 for electromagnetic brake is cut off. The minimum time t _e (c) (FIG. 3A) is the minimum time from when the AC power supply of the DC power supply device 20B for the electromagnetic brake of the fourth conventional example is cut off until the brake current I is cut off. It becomes shorter than the time t _e (a) (FIG. 14A).

Further, the maximum time t _e (d) (FIG. 3 (b)) from when the AC power supply of the electromagnetic brake DC power supply 2 is cut off until the brake current I is cut off is also the electromagnetic brake of the fourth conventional example. It becomes shorter than the maximum time t _e (b) (FIG. 14 (b)) from when the AC power source of the power DC power supply device 20B is cut off until the brake current I is cut off.

  Therefore, on average, the time from when the AC power supply of the electromagnetic brake DC power supply device 2 according to the present embodiment is cut off until the brake current I is cut off is the DC power supply for the electromagnetic brake of the fourth conventional example. It becomes shorter than the time from when the AC power supply of the device 20B is cut off until the brake current I is cut off.

The variation BA2 in time from when the AC power supply of the electromagnetic brake DC power supply device 2 according to the present embodiment is cut off until the brake current I is cut off is shown in FIG.
_{BA2 = t e (d) -t} e (c) = t (c) = t b (c)
The variation BA1 in the time from when the AC power supply of the electromagnetic brake DC power supply device 20B of the fourth conventional example is cut off until the brake current I is cut off is shown in FIG.
_{BA1 = t e (b) -t} e (a) = t (a) = t b (a)
From FIG. 3 and FIG.
t _b (c) <t _b (a)
Therefore,
BA2 <BA1
The variation BA2 in the time from when the AC power supply of the electromagnetic brake DC power supply device 2 according to the present embodiment is cut off until the brake current I is cut off is the DC power supply device for the electromagnetic brake of the fourth conventional example. It becomes smaller than the variation BA1 in the time from when the 20B AC power supply is cut off until the brake current I is cut off.

Thus, in this embodiment, the charge / discharge circuit 300a is frequently charged with the output voltage of the full-wave rectifier circuit 150. Therefore, the time constant τ2 of the charge / discharge circuit 300a is set to the time constant τ1 of the fourth conventional example (see FIG. 14) It can be set smaller. Therefore, when the input of the AC voltage to the DC power supply device 2 for electromagnetic brake is cut off, the brake current I flowing through the half-wave rectifier circuit 100a is cut off by the FET 18 in a shorter time than the case of the fourth conventional example. The electromagnetic brake 3 can be operated in a shorter time than the fourth conventional example. Further, it is possible to reduce the variation in time from when the AC voltage input is cut off until the brake current I is cut off, and to reduce the variation in the operation timing of the electromagnetic brake 3.

  Further, in the brake-equipped motor 1 in which the electromagnetic brake DC power supply device 2, the electromagnetic brake 3, and the motor 4 according to the present embodiment are combined, the electromagnetic brake DC power supply device 2 and the motor 4 are connected to the same electromagnetic contactor 43. Even when the motor is configured to be cut off, the brake current I is cut off when the residual voltage of the motor 4 becomes lower than the reference voltage, so that the electromagnetic brake 3 can be operated in a shorter time than a conventional motor with a brake. I can do it.

  Further, since the decrease in the output voltage of the full-wave rectifier circuit 100a is detected and the brake current I is interrupted by the FET 18, the control system using the brake electromagnetic contactor as described in the second conventional example and the brake Without adding wiring, the brake motor can be stopped at a higher speed than the first conventional example, the second conventional example, and the fourth conventional example. And the problem of the position shift in the reduction gear or electric cylinder which attached the motor with a brake can be solved.

  The capacitor 19 connected between the gate and source of the FET 18 is charged when the full-wave rectified voltage is higher than the reference voltage in the voltage comparison circuit 200a, and when it is low, the resistor 19 connected in parallel is charged. The voltage across the capacitor 19 is input to the FET 18 as a gate-source voltage. As a result, when the full-wave rectified voltage becomes higher than the reference voltage every period, the FET 18 continues to conduct, and when the full-wave rectified voltage is lower than the reference voltage, the voltage across the capacitor 19 is changed. The FET 18 is cut off below the gate voltage threshold of the FET 18. Therefore, the power supply circuit for driving the FET as in the third conventional example is unnecessary.

  As described above, the electromagnetic brake DC power supply device 2 according to the present embodiment does not require the comparator DC power supply circuit and the gate drive DC power supply circuit as compared with the third conventional example, and the heat generation amount is reduced. A small configuration can be realized with a small number of points. Therefore, it is possible to store in the motor terminal box of a small motor, and it is necessary to store the DC power supply for electromagnetic brake in the control panel and to perform wiring with the motor terminal box. The problem can be solved.

  Further, by setting the Zener voltage of the Zener diode 21 used for this reference voltage to be equal to or lower than the rated voltage between the gate and the source of the FET 18, the Zener diode 21 is added to the setting of the reference voltage of the voltage comparison circuit 200a and the gate of the FET 18. It plays both applications with maximum voltage regulation.

(Embodiment 2)
FIG. 4 is a block diagram illustrating a configuration example of an electromagnetic brake device including the DC power supply device for an electromagnetic brake which is a second embodiment of the DC power supply device according to the present invention. In this electromagnetic brake device, the auxiliary contact 43c of the electromagnetic contactor 43 is connected to the DC power supply device 2A for electromagnetic brake.

  FIG. 5 is a circuit diagram showing a configuration example of the electromagnetic brake DC power supply device 2A. In this electromagnetic brake DC power supply device 2A, terminals 2e and 2f connected to the auxiliary contact 43c are provided between the input terminal 2a and the output terminal 2c, and a surge absorbing element 11B is connected between the terminals 2e and 2f. A DC current cut-off circuit 400 (switching circuit) is configured, and when the stop push button switch 42 is pressed and the electromagnetic contactors 43 and 44 (FIG. 4) are de-energized, the contact 44a is connected to the electromagnetic brake DC. The power supply of the power supply device 2A is cut off, and the auxiliary contact 43c cuts off the brake current I from the half-wave rectifier circuit 100a.

When the start pushbutton switch 41 is pressed, the coil of the electromagnetic contactor 43 is excited, the auxiliary contact 43c is closed, and the state is the same as in the first embodiment (a state where the terminals 2e and 2f are short-circuited). When the stop push button switch 42 is pressed, the coil of the electromagnetic contactor 43 is de-energized, the auxiliary contact 43c is opened, and the brake current is cut off.
Other configurations and operations are the same as the configurations and operations of the electromagnetic brake device (FIG. 1) and the electromagnetic brake DC power supply device 2 (FIG. 2) described in the first embodiment. A description thereof will be omitted.

In this embodiment, since the time from when the three-phase AC power supply is cut off until the brake current is cut off is about 0 sec, when the power supply voltage in FIG. 6 (a) switches from the negative cycle to the positive cycle, As shown in the timing chart when the three-phase alternating current power supply is cut off, and the timing chart when the three-phase alternating current power supply is turned off when the power supply voltage in FIG. 6B is the maximum value of the positive cycle, respectively. It is not necessary to consider the variation of those times t _e (e) and t _e (f).

  In the present embodiment, if it is necessary to shorten the time from when the three-phase AC power is cut off until the brake current is cut off depending on the usage, an external contact (auxiliary contact 43c) is connected between the terminals 2e and 2f. ) Is inserted and controlled, and if shortening is not necessary, the same function as in the first embodiment can be obtained by short-circuiting the terminals 2e and 2f.

(Embodiment 3)
FIG. 7 is a block diagram showing a configuration example of an electromagnetic brake device including the electromagnetic brake DC power supply device according to the third embodiment of the DC power supply device of the present invention. In this electromagnetic brake device, an electromagnetic contactor 44 is connected in parallel to an electromagnetic contactor 43, and an electromagnetic brake DC power supply device 2B is connected to a terminal R and a terminal S via a contact 44a of the electromagnetic contactor 44, respectively. Is supplied. The auxiliary contact 43c of the electromagnetic contactor 43 is connected to the electromagnetic brake DC power supply 2B. Other configurations are the same as the configuration of the electromagnetic brake device (FIG. 1) described in the first embodiment, and thus the same portions are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 8 is a circuit diagram showing a configuration example of the DC power supply device 2B for electromagnetic brake. This DC power supply device 2B for electromagnetic brake includes a diode 123 having a surge absorbing element 121 connected between the input terminals 2a and 2b, an anode connected to the input terminal 2a, and a diode 124 having an anode connected to the input terminal 2b. Are connected by each cathode. The diode 124 is a flywheel diode. Diodes 123 and 124 constitute half-wave rectifier circuit 100.

  Resistors 132 and 133 are connected in series between the cathode of the diode 123 and the anode of the diode 124, and the connection node of the resistors 132 and 133 is connected to the emitter of the PNP transistor 127. A resistor 134 is connected between the emitter and base of the transistor 127, and a cathode of a Zener diode 131 whose anode is connected to the anode of the diode 124 is further connected to the base.

  The collector of the transistor 127 is connected to the anode of the diode 126, and the cathode of the diode 126 is connected to one terminal of a resistor 135 whose other terminal is connected to the anode of the diode 124.

  The cathode of the diode 126 is connected to one terminal of a capacitor 130 whose other terminal is connected to the anode of the diode 124, and is further connected to the gate of an N-channel field effect transistor (FET) 128. The source of the FET 128 is connected to the anode of the diode 124, the drain thereof is connected to the output terminal 2d, and the surge absorbing element 122 is connected between the output terminals 2c and 2d.

  Terminals 2e and 2f connected to the auxiliary contact 43c are provided between the output terminal 2c and the input terminal 2a, and a surge absorbing element 11B is connected between the terminals 2e and 2f to constitute a DC cutoff circuit 400 (switching circuit). Has been.

  In the electromagnetic brake device and the electromagnetic brake DC power supply device 2B configured as described above, when the stop push button switch 42 is pressed and the electromagnetic contactors 43 and 44 (FIG. 7) are de-energized, the contact 44a is electromagnetic The power supply to the brake DC power supply 2B is cut off, and the auxiliary contact 43c cuts off the brake current I from the half-wave rectifier circuit 100. Other operations are the same as the operations of the electromagnetic brake device (FIG. 11) and the electromagnetic brake DC power supply device 20B (FIG. 13) described in the fourth conventional example. The same reference numerals are given and the description is omitted.

In this embodiment, since the time from when the three-phase AC power supply is cut off until the brake current is cut off is about 0 sec, when the power supply voltage in FIG. 6 (a) switches from the negative cycle to the positive cycle, As shown in the timing chart when the three-phase alternating current power supply is cut off, and the timing chart when the three-phase alternating current power supply is turned off when the power supply voltage in FIG. 6B is the maximum value of the positive cycle, respectively. It is not necessary to consider the variation of those times t _e (e) and t _e (f).

  In the present embodiment, if it is necessary to shorten the time from when the three-phase AC power is cut off until the brake current is cut off depending on the usage, an external contact (auxiliary contact 43c) is connected between the terminals 2e and 2f. ) Is inserted and controlled, and if shortening is not necessary, the same function as in the fourth conventional example can be obtained by short-circuiting the terminals 2e and 2f.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the structural example of an electromagnetic brake apparatus provided with the DC power supply device for electromagnetic brakes which is Embodiment 1 of the DC power supply device which concerns on this invention. 1 is a circuit diagram (Embodiment 1) showing a configuration example of a DC power supply device for an electromagnetic brake of the present invention. It is a timing chart which shows operation | movement of the electromagnetic brake device shown in FIG. It is a block diagram which shows the structural example of an electromagnetic brake apparatus provided with the DC power supply device for electromagnetic brakes which is Embodiment 2 of the DC power supply device which concerns on this invention. It is a circuit diagram (Embodiment 2) which shows the other structural example of the DC power supply device for electromagnetic brakes of this invention. 8 is a timing chart showing the operation of the electromagnetic brake device shown in FIGS. It is a block diagram which shows the structural example of an electromagnetic brake apparatus provided with the DC power supply device for electromagnetic brakes which is Embodiment 3 of the DC power supply device which concerns on this invention. It is a circuit diagram (Embodiment 3) which shows the other structural example of the DC power supply device for electromagnetic brakes of this invention. It is a block diagram which shows the structural example of an electromagnetic brake apparatus (1st prior art example) provided with the DC power supply device for conventional electromagnetic brakes. It is a circuit diagram (the 1st conventional example) which shows the example of composition of the conventional DC power unit for electromagnetic brakes. It is a block diagram which shows the structural example of the electromagnetic brake device (2nd, 3rd, 4th conventional example) provided with the DC power supply device for conventional electromagnetic brakes. It is a block diagram which shows the structural example of the conventional DC power supply device for electromagnetic brakes (3rd prior art example). It is a circuit diagram which shows the structural example of the conventional DC power supply device for electromagnetic brakes (4th prior art example). It is a timing chart which shows operation | movement of the DC power supply device for electromagnetic brakes shown in FIG.

Explanation of symbols

1, 1A, 1B Motor with brake 2, 2A, 2B DC power supply for electromagnetic brake 3 Electromagnetic brake 4 Motor 13, 13A, 14, 14A, 16, 123, 124, 126 Diode 17, 127 Transistor 18, 128 FET
19, 130 Capacitor 21, 131 Zener diode 22, 23, 24, 25, 132, 133, 134, 135 Resistance 43, 44 Electromagnetic contactor 43a Contact 43b Auxiliary contact 44a Contact 100, 100a Half-wave rectifier circuit 150 Full wave rectifier circuit 200a Voltage comparison circuit 300a Charge / discharge circuit 400 DC cutoff circuit (switching circuit)

Claims (3)

In a DC power supply that supplies a DC current based on input AC power to an external device,
Full-wave rectification circuit for full-wave rectification of the AC power, voltage comparison circuit for comparing the output voltage of the full-wave rectification circuit and a reference voltage, and charging / discharging are repeated according to the comparison result of the voltage comparison circuit A charge / discharge circuit; and a field effect transistor connected between the gate and the source of the charge / discharge circuit, and configured to energize / cut off the direct current by turning on / off the field effect transistor. A direct current power supply device.   The DC power supply device according to claim 1, further comprising a switching circuit for switching energization / cutoff of the DC current from the outside. Half-wave rectification circuit for half-wave rectification of input AC power, voltage comparison circuit for comparing the output voltage of the half-wave rectification circuit and a reference voltage, and charging / discharging according to the comparison result in the voltage comparison circuit And a field effect transistor connected between the gate and the source of the charge / discharge circuit, supplying a direct current based on the AC power to an external device, and turning on / off the field effect transistor. A DC power supply device configured to energize / cut off the DC current when turned off,
A DC power supply device comprising: a switching circuit for switching energization / cutoff of the DC current from the outside.

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