JP4794600B2 - DC power supply for electromagnetic brake - Google Patents

Description

The present invention relates to a direct-current power supply for the electromagnetic brake for driving the electromagnetic brake.

  The non-excitation operation type electromagnetic brake brakes the motion state of the motor or actuator when the current to the coil is cut off and stops it, and releases the brake when the coil is energized. Such an electromagnetic brake has a problem that when energization is performed to release braking, the electromagnetic force generated by coil excitation is not sufficient due to the reactance of the coil, and the release of braking is delayed. Although the release of braking can be speeded up by increasing the voltage applied to the coil of the electromagnetic brake, there is a problem that the current consumption after releasing the braking increases and the amount of heat generation increases. In order to solve these problems, the DC power supply that drives the electromagnetic brake applies a high voltage immediately after the start of energization of the coil of the electromagnetic brake, and after a certain period of time has passed, the coil is released The applied voltage is controlled so as to reduce the applied voltage. As a result, the release of braking can be speeded up, and the current consumption after the release of braking can be reduced.

In addition, including the above points, main functions required for the DC power supply for driving the electromagnetic brake are as shown in the following (1) to (4).
(1) A function to release the brake at high speed when energization is started (overexcitation output function).
(2) A function that quickly cuts off the current to the electromagnetic brake at the end of energization and performs braking instantaneously (fast cut function).
(3) A function to always perform overexcitation output when energization is started for braking even when braking / release is switched in a short period of time (inching operation).
(4) A function of reducing the heat generation amount by reducing the current consumption after the completion of the release of braking.

  In Patent Document 1, by applying a high voltage to an electromagnetic device at the start of energization and gradually decreasing the voltage as time elapses, braking of the electromagnetic device can be quickly released, and braking is performed. There has been proposed an efficient DC power supply device for an electromagnetic device that can suppress power consumption after release and can quickly release the braking force quickly even when braking is released immediately after re-braking. . In Patent Document 1, a DC power supply device for an electromagnetic device uses a full-wave rectifier circuit in which two SCRs (silicon controlled rectifiers) are connected in series and a trigger signal via a trigger element connected to the gate of the SCR. A first capacitor that provides a negative polarity, a diode that prevents charging of the first capacitor with the opposite polarity, a second capacitor that is interposed in the charging circuit of the first capacitor, and a discharge circuit that is connected to the second capacitor. There is disclosed a technique that includes a switch that closes when power supply is stopped and delays the phase of a trigger signal applied from the first capacitor to the SCR as the charging voltage of the second capacitor increases.

  In Patent Document 2, a first monostable multivibrator capable of switching a threshold voltage that limits a predetermined time from the start of energization, and the first monostable multivibrator are conducted in synchronization with the output signal of the first monostable multivibrator. A power switch element that supplies current to a load by controlling the angle, and a second monostable multivibrator that is activated by detecting positive and negative cycles of a commercial power source and determines a conduction angle of the power switch element A power supply device for electromagnetic equipment has been proposed. In Patent Document 2, since the power supply device applies a voltage obtained by full-wave rectification of the commercial AC power source for a certain time during overexcitation after energization of the coil of the electromagnetic device is started, the responsiveness of the electromagnetic device is improved. In addition, it is mentioned that an energy saving operation can be realized because a full-wave rectified voltage with a controlled conduction angle can be applied in a steady state after the end of overexcitation.

Moreover, in the apparatus which operate | moves with the alternating voltage supplied from commercial alternating current power supply, the difference (50 Hz or 60 Hz) of the frequency of alternating voltage may be a problem. As a countermeasure, in Patent Document 3, a zero cross of a power supply voltage is detected, a power supply frequency is determined from a zero cross pulse of a detection result, and a pump control phase is switched based on the determination result, thereby maintaining a pump output constant. A pump drive circuit that can do this has been proposed.
Japanese Examined Patent Publication No. 2-61236 Japanese Patent No. 3341547 JP 58-79497 A

  In a conventional DC power supply device that drives an electromagnetic device, a contact relay is used to switch between energization / non-energization of the electromagnetic device. A contact relay used in a DC power supply device of an electromagnetic device has an electrical life of switching about 200,000 times. The use of a contact relay with a large capacity (maximum voltage and maximum current for contact opening and closing) can extend the electrical life, but the shape of the contact relay becomes larger, and the installation of the contact relay in a DC power supply device This causes a problem that the cost increases. The same applies to the DC power supply device described in Patent Document 1.

  Moreover, it is desirable that the DC power supply device that drives the electromagnetic device has the functions (1) to (4). The power supply device described in Patent Document 2 can apply a high voltage at the start of energization and then reduce the applied voltage, so that (1) the overexcitation output function and (4) the amount of heat generation is reduced. It has the function to do. However, this power supply device does not take into account (2) the quick cut function and (3) the overexcitation output function during the inching operation. In addition, the pump drive circuit described in Patent Document 3 does not take into consideration the above-described (1) overexcitation output function, (2) early cut-off function, and (3) overexcitation output function during inching operation.

The present invention has been made in view of such circumstances, and the object of the present invention is to solve problems such as a short life and an increase in the size of the device by using a contact relay, thereby extending the life and Achieving downsizing, high voltage can be applied to the load at the start of energization, the current flowing through the load can be shut off at high speed, and even when braking / release is switched over in a short time It is an object of the present invention to provide an electromagnetic brake direct-current power supply device that can always apply a high voltage and can reduce current consumption after completion of braking.

A DC power supply for an electromagnetic brake according to a first aspect of the present invention is a full-wave rectifier circuit that outputs a DC voltage by full-wave rectifying an input AC voltage, and a DC voltage output from the full-wave rectifier circuit to an electromagnetic brake . a switching circuit for switching the application / non-application, a DC power supply for the electromagnetic brake and a control circuit for controlling the switching of said switching circuit, arranged by application of the DC voltage in the path of current through the electromagnetic brake And a switching circuit for cutting off current by the semiconductor switching element after the input of AC voltage is stopped and energization to the electromagnetic brake is terminated. A full-wave rectifier circuit comprising three diodes connected in a bridge and one silicon controlled rectifier element; Has, under the control of the silicon controlled rectifier, Ri Citea so as to provide an output stop period of the DC voltage, the control circuit until the predetermined period from the input start of the AC voltage has passed, continuously the DC voltage The high voltage is applied to the brake by applying the voltage to the brake, and after the predetermined period, the application time is adjusted and the low voltage is applied to the electromagnetic brake by repeating the application / non-application of the DC voltage. The switching of the switching circuit is controlled so as to be possible, and the application time is less than half of the period of the AC voltage .

In the present invention, the AC voltage input to the DC power supply device is full-wave rectified by the full-wave rectifier circuit, and application / non-application of the full-wave rectified voltage to the load is switched by the switching circuit. By appropriately controlling switching of the switching circuit, for example, a high voltage is applied to a load such as an electromagnetic brake at the start of energization to operate at high speed, and thereafter, the applied voltage is reduced to reduce current consumption. it can.
The DC power supply device cuts off the current flowing through the load when the input of the AC voltage is stopped using a semiconductor switching element (for example, a field effect transistor) having no contact, without using a contact relay. Since the semiconductor switching element has a longer life and is smaller than a contact relay, the life of the DC power supply device can be extended and reduced in size.
Further, the DC power supply device switches application / non-application of the voltage, which is full-wave rectified by the full-wave rectifier circuit, to the load using the silicon-controlled rectifier element. The silicon controlled rectifier element is small and inexpensive, and can easily control conduction / non-conduction. However, in order to switch the silicon-controlled rectifier element from the conductive state to the non-conductive state, the current flowing through the silicon-controlled rectifier element needs to be stopped for a certain period (the current is set to 0). Therefore, the full-wave rectifier circuit is configured by bridge-connecting three diodes and one silicon control rectifier element, and provides a period for stopping the voltage output of the full-wave rectifier circuit by controlling the silicon control rectifier element. As a result, the current flowing through the switching silicon control rectifier element can be stopped, and the silicon control rectifier element can be reliably switched from the conductive state to the non-conductive state.
Further, in the present invention, switching is controlled so that the full-wave rectifier circuit continuously applies the full-wave rectified output voltage to the load until a predetermined period elapses after the AC voltage input is started. Thereby, for example, a high voltage can be applied to a load such as an electromagnetic brake at the start of energization, and braking can be released at high speed.
After the predetermined period, the application of the output voltage of the full-wave rectifier circuit to the load is repeated and the amount of current flowing through the load is adjusted by adjusting the application time. That is, after elapse of a predetermined period, application / non-application to the load is controlled by so-called phase control. As a result, current consumption can be reduced after a predetermined period.

Further, in the DC power supply device for electromagnetic brake according to the second invention, the full-wave rectifier circuit includes a diode and a resistor connected in series between the gate and the anode of the silicon control rectifier element. .

  In the present invention, a diode and a resistor connected in series are connected between the gate and the anode of the silicon controlled rectifier of the full-wave rectifier circuit, and the operation of the silicon controlled rectifier is controlled using the diode and the resistor. As a result, the output of the full-wave rectifier circuit can be stopped until the current flowing to the gate of the silicon controlled rectifier element via the resistor and the diode exceeds a certain amount, and the resistance value of the resistor is adjusted. Thus, the current flowing through the gate of the silicon controlled rectifier element can be adjusted, and the period during which the full-wave rectifier circuit stops outputting can be adjusted.

The diode for the electromagnetic brake DC power supply device according to the third invention, the semiconductor switching element, the Yes and connected in series with the electromagnetic brake, connected in parallel to said electromagnetic brake and the semiconductor switching elements connected in series And the blocking circuit is configured to perform blocking by the semiconductor switching element in accordance with an output voltage of the full-wave rectifier circuit.

  In the present invention, when the DC power supply device has a diode (so-called flywheel diode or freewheel diode) connected in parallel to the load, the semiconductor switching element of the cutoff circuit is connected in series to the load and is connected in series. The diode is connected in parallel to the load and the semiconductor switching element. The DC power supply device controls conduction / non-conduction of the semiconductor switching element according to the output voltage of the full-wave rectifier circuit. Accordingly, since the current flowing through the diode can be cut off by the inductive load, when the AC voltage is stopped, the high-speed cut-off of the current flowing through the load can be realized.

According to a fourth aspect of the present invention, there is provided the DC power supply for an electromagnetic brake according to the first and second resistors , wherein the interrupting circuit is connected in series between the high potential side output and the low potential side output of the full-wave rectifier circuit. A capacitor and a Zener diode connected in parallel to the second resistor, respectively, and controlling the semiconductor switching element according to the voltage between the first resistor and the second resistor. Features.

In the present invention, the semiconductor switching element can be de-energized in response to a decrease in the output voltage of the full-wave rectifier circuit.

In the DC power supply for electromagnetic brake according to the fifth aspect of the invention, the control circuit detects a time constant circuit of a resistor and a capacitor for determining the application time, and a positive amplitude period or a negative amplitude period of an input AC voltage. And a photocoupler that determines a frequency of an AC voltage based on a detection result of the photocoupler, and adjusts a time constant of the time constant circuit according to the frequency.

  In the present invention, as described above, after a predetermined period has elapsed from the start of AC voltage input, the application time is adjusted to repeatedly apply / do not apply the output voltage of the full-wave rectifier circuit to the load. The application time is determined by the time constant of a time constant circuit using resistors and capacitors. Furthermore, the positive or negative amplitude period of the input AC voltage is detected by a photocoupler, the frequency of the AC voltage is determined based on the detection result, and the time constant of the time constant circuit is adjusted according to the frequency. . For example, there are two types of frequency of commercial AC power supply, 50 Hz or 60 Hz. By detecting this frequency and automatically adjusting it to a suitable time constant, the DC power supply can be connected to any frequency commercial AC power supply. Can be used.

According to a sixth aspect of the present invention, there is provided the DC power supply for electromagnetic brake according to the sixth aspect of the present invention, wherein the control circuit includes a time constant circuit for resistors and capacitors for determining the predetermined period, and the time constant circuit when input of AC voltage is stopped. And a discharge circuit for discharging the charge stored in the capacitor.

  In the present invention, the predetermined period from the start of input of the AC voltage is determined by the time constant of the time constant circuit of the resistor and the capacitor, and the voltage applied to the load is reduced after the lapse of the predetermined period. In addition, a discharge circuit is provided for discharging the charge stored in the capacitor of the time constant circuit when the input of the AC voltage is stopped. The time constant circuit operates as a timer, while the discharge circuit operates as a timer reset circuit. Even if the input of AC voltage is restarted immediately after that by discharging the capacitor when the input of AC voltage is stopped (that is, when the inching operation is performed), the time constant circuit Time keeping for a predetermined period is not shortened, and high voltage application to the load at the start of energization can be performed reliably.

In the case of the first invention, the semiconductor switching element has a longer life and is smaller than that in the case of using the contact relay to cut off the current flowing through the load using the semiconductor switching element. Therefore, it is possible to extend the life and size of the DC power supply device.
In addition, by adopting a configuration in which a switching circuit switches between application and non-application of a voltage that is full-wave rectified by a full-wave rectifier circuit, a high voltage is applied to a load such as an electromagnetic brake at the start of energization. It is possible to operate at high speed, and thereafter, the applied voltage can be reduced to reduce current consumption. At this time, the switching circuit switches between application / non-application using the silicon controlled rectifier element, and the switching of voltage application using the silicon controlled rectifier element is ensured by providing a period during which the full-wave rectifier circuit stops voltage output. It can be carried out.
Therefore, a DC power supply device that can apply a high voltage to the load at the start of energization, cut off the current to the load at high speed, and reduce current consumption after the completion of braking release. It is possible to realize a long life and miniaturization of the DC power supply by satisfying the functions required for the above.
In addition, the output voltage of the full-wave rectifier circuit is continuously applied to the load until the predetermined period elapses after the AC voltage input starts, and the application time of the output voltage of the full-wave rectifier circuit is set after the predetermined period elapses By adjusting and repeating the application / non-application, a high voltage can be applied to the load at the start of energization, and the voltage applied to the load can be reduced after a predetermined period. Therefore, for example, a high voltage can be applied to a load such as an electromagnetic brake at the start of energization to release the brake at high speed, and after a predetermined period, the applied voltage to the load is reduced to reduce current consumption and heat generation The amount can be reduced.

  According to the second aspect of the present invention, the current that flows to the gate of the silicon controlled rectifier through the resistor and the diode is configured by connecting the diode and the resistor connected in series between the gate and the anode of the silicon controlled rectifier. Since the output of the full-wave rectifier circuit can be stopped during a period until the value exceeds a certain amount, a period during which the full-wave rectifier circuit stops voltage output can be provided easily and reliably.

  In the case of the third invention, the semiconductor switching element of the cutoff circuit is connected in series to the load, the diode is connected in parallel to the load and the semiconductor switching element connected in series, and the full-wave rectifier circuit By adopting a configuration that controls conduction / non-conduction of the semiconductor switching element according to the output voltage, it is possible to cut off the current flowing through the diode and cut off the current flowing through the load. Therefore, since the current flowing through the load can be quickly cut off by the semiconductor switching element when the AC power supply is stopped, for example, the current is cut off at a high speed at the end of energization of the load such as an electromagnetic brake so that the braking is performed at a high speed. be able to.

In the case of the fourth invention, since the semiconductor switching element can be de-energized in accordance with a decrease in the output voltage of the full-wave rectifier circuit, the current flowing through the electromagnetic brake when the AC voltage input is stopped The semiconductor switching element can quickly shut off.

  According to the fifth aspect of the invention, the voltage application time to the load after the lapse of a predetermined period is determined by the time constant of the time constant circuit, and the time constant circuit By adopting a configuration that adjusts the time constant, the output voltage to the load can be kept constant without being affected by the frequency of the AC voltage. Therefore, for example, the DC power supply can be used regardless of whether it is connected to a commercial AC power supply of 50 Hz or 60 Hz, so that the versatility and convenience of the DC power supply can be improved.

  According to the sixth aspect of the invention, the time constant circuit of the resistor and the capacitor that determines the predetermined period is configured to discharge the electric charge stored in the capacitor when the input of the AC voltage is stopped. Even if the input of AC voltage is resumed immediately thereafter, the time constant circuit does not shorten the time for a predetermined period, and the high voltage can be reliably applied to the load at the start of energization. it can. Therefore, for example, when a DC voltage is applied to a load such as an electromagnetic brake to perform the operation, braking and braking release can be repeatedly performed at high speed, that is, an inching operation can be performed.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. FIG. 1 is a circuit diagram showing a configuration of a DC power supply device according to the present invention. FIG. 2 is a schematic diagram for explaining the operation of the DC power supply device according to the present invention. The DC power supply device according to the present invention includes a full-wave rectifier circuit 1, a switching circuit 2, a cutoff circuit 3, and a control circuit 4, and converts an AC voltage input from an AC power supply 8 into a DC voltage. A circuit to be applied to the load 9.

  The AC power supply 8 is a power supply that outputs an AC voltage having a frequency of 50 Hz or 60 Hz, and is connected to the two input terminals 11 and 12 of the DC power supply device. The AC voltage input from the AC power supply 8 to the DC power supply device is V1. The load 9 is, for example, a non-excited electromagnetic brake (coil), and when energization (application of DC voltage) is performed from the DC power supply, the braking of the motor or actuator is released and the energization is cut off. If this happens, braking can be performed. The load 9 is connected to the two output terminals 15 and 16 of the DC power supply device. The voltage applied from the DC power supply device to the load 9 is V3.

  The AC voltage from the AC power supply 8 is input to the full-wave rectifier circuit 1 of the DC power supply device. The full-wave rectifier circuit 1 includes three diodes D11, D12, and D13 and one silicon-controlled rectifier element SCR11 (hereinafter referred to as “bridge”) so that the AC power supply 8 connected to the input terminals 11 and 12 of the DC power supply device bridges. , Simply referred to as SCR11). Specifically, the cathode of the diode 12 is connected to the anode of the diode D11, the cathode of the diode D13 is connected to the anode of the SCR 11, the cathode of the diode D11 and the cathode of the SCR 11 are connected, and the anode of the diode D12 and the anode of the diode D13 Is connected. A connection point between the diodes D11 and D12 is connected to the input terminal 11, and a connection point between the SCR11 and the diode D13 is connected to the input terminal 12. Further, the full-wave rectifier circuit 1 has a connection point between the cathode of the diode D11 and the cathode of the SCR 11 as a high potential side output, and a connection point between the anodes of the diodes D12 and D13 as a low potential side output.

  The full-wave rectifier circuit 1 has a diode D14 and a resistor R11 for controlling energization / non-energization of the SCR 11. The diode D14 and the resistor R11 are connected in series between the gate and the anode of the SCR 11. Specifically, the cathode of the diode D14 is connected to the gate of the SCR 11, the one end of the resistor R11 is connected to the anode of the diode D14, and the other end of the resistor R11 is connected to the anode of the SCR 11. The connection between the diode D14 and the resistor R11 may be reversed.

  The AC power supply 8 outputs an AC voltage V1 whose amplitude periodically changes between positive and negative as shown in FIG. In the full-wave rectification circuit 1, when the amplitude of the AC voltage V1 is positive (when the input terminal 11 side is at a high potential), the forward voltage of the diode D11 is the threshold voltage (the voltage that makes the diode conductive and is about 0.7V). ), The voltage V2 is output. On the other hand, when the amplitude of the AC voltage V1 is negative (when the input terminal 12 side is at a high potential), the forward voltage of the diode D14 exceeds the threshold voltage and a gate current flows to the SCR 11, and this gate current is reduced to a predetermined amount. When it exceeds, the SCR 11 becomes conductive, and the full-wave rectifier circuit 1 outputs the voltage V2. Therefore, the full-wave rectifier circuit 1 starts output in a short period when the amplitude of the input AC voltage V1 is positive, but outputs for a predetermined period (output stop period Tb) when the amplitude is negative. (The output voltage is 0V), and the output is started after the output stop period Tb has elapsed (see FIG. 2B). The length of the output stop period Tb can be adjusted by adjusting the resistance value of the resistor R11.

  The voltage V <b> 2 that is full-wave rectified by the full-wave rectifier circuit 1 is input to the switching circuit 2. The switching circuit 2 is a circuit for switching application / non-application of the voltage V <b> 2 input from the full-wave rectifier circuit 1 to the load 9. The switching circuit 2 is connected to the high-potential side output of the full-wave rectifier circuit 1 to switch conduction / non-conduction of the path from the full-wave rectifier circuit 1 to the load 9, and the cathode of the SCR 21 and the full-wave rectifier circuit. 1 and a diode D21 connected between the low potential side outputs. The SCR 21 has an anode to which the high-potential side output of the full-wave rectifier circuit 1 is input, a cathode that is the high-potential side output of the switching circuit 2, and a gate that is connected to the control circuit 4. It is controlled by the control circuit 4. The diode D <b> 21 is a so-called flywheel diode or freewheel diode connected in parallel to the load 9 in order to absorb the voltage due to the counter electromotive force generated in the load 9, and the anode is on the low potential side of the full-wave rectifier circuit 1. Connected to the output, the cathode is connected to the cathode of the SCR 21. In the present embodiment, the switching circuit 2 includes the diode D21. However, when the load 9 is not an inductive load, the switching circuit 2 does not necessarily have the diode D21. On the other hand, when the load 9 is an inductive load, it is only necessary that the diode D21 is connected in parallel with at least the load 9 in the DC power supply circuit.

  The output voltage of the switching circuit 2 is output from the output terminals 15 and 16 of the DC power supply circuit via the cutoff circuit 3 and applied to the load 9. The cutoff circuit 3 includes a field effect transistor T31 that is a semiconductor switching element connected in series to a load 9, and resistors R31 and R32, a capacitor C31, and a Zener diode for controlling conduction / non-conduction of the field effect transistor T31. And a circuit constituted by ZD31. Specifically, the drain of the field effect transistor T31 is connected to the load 9 via the output terminal 16, and the source is connected to the low potential side output (of the switching circuit 2) of the full-wave rectifier circuit 1. The resistors R31 and R32 of the breaking circuit 3 are connected in series between the high-potential side output and the low-potential side output of the full-wave rectifier circuit 1, and the potential at the connection point of the resistors R31 and R32 is an electric field. The signal is input to the gate of the effect transistor T31. Further, a capacitor C31 and a Zener diode ZD31 are connected in parallel to the resistor R32. A circuit composed of resistors R31 and R32, a capacitor C31, and a Zener diode ZD31 controls conduction / non-conduction of the field effect transistor T31 according to the output voltage of the full-wave rectification circuit 1. Note that the voltage between the gate and the source of the field effect transistor T31 is V4 (see FIG. 2D).

  When the AC power supply 8 starts to output the AC voltage V1 and the full-wave rectifier circuit 1 starts to output the voltage V2, a current flows through the resistors R31 and R32 of the breaking circuit 3 to charge the capacitor C31. The gate-source voltage V4 of the effect transistor T31 increases. Immediately after the output of the AC power supply 8 is started, the control circuit 4 controls the SCR 21 of the switching circuit 2 to be in a conductive state, but the field effect transistor T31 is in a non-conductive state until the voltage V4 exceeds the threshold voltage. The current I does not flow through the load 9. Thereafter, when the voltage V4 exceeds the threshold voltage and the field effect transistor T31 becomes conductive, the voltage V3 is applied to the load 9 and the current I starts to flow (see FIG. 2E). Note that the gate-source voltage V4 of the field effect transistor T31 is kept constant by the Zener diode ZD31.

  The control circuit 4 controls the SCR 21 of the switching circuit 2 to be in a conductive state until the predetermined period elapses after the AC power supply 8 starts outputting the AC voltage V1 (overexcitation output period Ta). Therefore, after the field effect transistor T31 of the cutoff circuit 3 is turned on in the overexcitation output period Ta, the voltage V2 that is full-wave rectified by the full-wave rectifier circuit 1 is continuously applied to the load 9 through the SCR 21 of the switching circuit 2. The current I flowing through 9 increases and reaches a constant value.

  After the overexcitation output period Ta has elapsed, the control circuit 4 periodically applies the voltage V2 that is full-wave rectified by the full-wave rectifier circuit 1 to the load 9 by conducting the SCR 21 of the switching circuit 2 at a constant cycle Tc. (See voltage V3 in FIG. 2C). At this time, the current I flowing through the load 9 periodically increases and decreases.

  Thereafter, when the output of the AC voltage V1 of the AC power supply 8 is stopped, the full-wave rectifier circuit 1 does not output the voltage V2, so that the application of the voltage V3 to the load 9 is stopped. At this time, the gate-source voltage V4 of the field effect transistor T31 of the cutoff circuit 3 gradually decreases because the charge stored in the capacitor C31 is discharged through the resistor R32, and the field effect transistor T31 is in an energized state. Transition from non-energized state. After the application of the voltage V3 by the DC power supply circuit is stopped, the current I flowing through the load 9 gradually decreases, but is interrupted when the field effect transistor T31 of the cutoff circuit 3 becomes non-conductive.

  As described above, the control circuit 4 controls the application / non-application of the DC voltage to the load 9 by controlling the conduction / non-conduction of the SCR 21 by controlling the gate current of the SCR 21 of the switching circuit 2. The control circuit 4 monitors the photocoupler PC41 for detecting the positive amplitude period of the AC voltage V1 input from the AC power supply 8, and the output start, output stop and frequency of the AC voltage V1 based on the detection result. Power supply monitoring circuit 41, a time constant switching circuit 42 for defining the switching timing of the SCR 21 of the switching circuit 2, a timer circuit 43 and a timer reset circuit 44 for defining the overexcitation output period Ta, The driving circuit 45 is configured to drive the SCR 21 under the control of the time constant switching circuit 42 and the timer circuit 43.

  In the photocoupler PC41, a light emitting element and a light receiving element are housed in a package, an input electric signal is converted into light by the light emitting element, and the light is received by the light receiving element and converted into an electric signal. It is an element that transmits and receives signals in a state of being electrically insulated. The photocoupler PC41 is connected between the input terminals 11 and 12 of the DC power supply device, and receives the AC voltage V1 input from the AC power supply 8. In the photocoupler PC41, a light receiving element such as a phototransistor can receive light and output a detection signal during a period in which light is emitted by applying a forward voltage to the light emitting element such as a light emitting diode by the AC voltage V1. . In the present embodiment, the photocoupler PC41 emits light when a forward voltage is applied to the light emitting element when the amplitude of the AC voltage V1 is positive, and the light receiving element outputs an “H” signal as a detection signal. To do. However, the photocoupler PC41 may be connected in reverse to output an “H” signal when the amplitude of the AC voltage V1 is negative.

  The power monitoring circuit 41 receives the detection signal of the photocoupler PC41. From the detection signal of the photocoupler PC41, it is possible to obtain information such as whether the AC voltage V1 is input, the rising timing of the AC voltage V1, or the frequency of the AC voltage V1. The power monitoring circuit 41 outputs an output signal corresponding to the information to the time constant switching circuit 42 and the timer circuit 43.

  The time constant switching circuit 42 defines a timing (timing to switch application / non-application of the voltage V3 to the load 9) when the SCR 21 of the switching circuit 2 is switched after the overexcitation output period Ta has elapsed. And the time constant of the time constant circuit can be switched according to the frequency of the AC voltage V1. The time constant switching circuit 42 defines a timing suitable for the frequency of the AC voltage V1 by switching the time constant, and outputs an output signal corresponding to this timing to the drive circuit 45.

  The timer circuit 43 is a circuit that defines an overexcitation output period Ta from the start of output of the AC voltage V1 by the AC power supply 8, and transmits the passage of the overexcitation output period Ta to the drive circuit 45. The timer reset circuit 44 is a circuit that resets the time counting of the overexcitation output period Ta by the timer circuit 43 when the output of the AC voltage V1 by the AC power supply 8 is stopped. Thereby, the timer circuit 43 accurately measures the overexcitation output period Ta even when the output of the AC voltage V1 is restarted immediately after the output of the AC voltage V1 by the AC power supply 8 is stopped. Can do.

  The drive circuit 45 is a circuit for generating a gate current input to the SCR 21 of the switching circuit 2. The drive circuit 45 generates and outputs a gate current so that the SCR 21 continues to be conductive from the start of output of the AC voltage V1 by the AC power supply 8 until the overexcitation output period Ta measured by the timer circuit 43 elapses. . Further, after the elapse of the overexcitation output period Ta, the drive circuit 45 generates and outputs a gate current so that the SCR 21 is periodically conducted according to the timing defined by the time constant switching circuit 42.

  FIG. 3 is a circuit diagram illustrating an example of a detailed configuration of the control circuit 4. FIG. 4 is a schematic diagram for explaining the operation of the control circuit 4 when the frequency of the AC voltage V1 is 50 Hz. FIG. 5 is a schematic diagram for explaining the operation of the control circuit 4 when the frequency of the AC voltage V1 is 60 Hz. The photocoupler PC41 of the control circuit 4 applies a forward voltage to the light emitting diode of the light emitting element when the amplitude of the AC voltage V1 input from the AC power supply 8 is positive (when the input terminal 11 side is at a high potential). Since the light emitting diode emits light when the voltage exceeds the threshold voltage, a detection signal of “H” is output by the phototransistor of the light receiving element (see FIGS. 4B and 5B).

  The control circuit 4 has a multivibrator MB41 to which the detection signal of the photocoupler PC41 is input. The multivibrator MB41 is a so-called retriggerable multivibrator, which outputs a pulse signal for a certain period when a trigger signal is input, and is outputting when a trigger signal is input again during the output of the pulse signal. This is a circuit that can further output a pulse signal of a certain period. The multivibrator MB41 outputs an “H” signal for a certain period from the output 1 (see FIG. 4C) in accordance with the rising edge of the input signal, and outputs an “L” signal for a certain period of time 2 (FIG. 4 (FIG. 4). (see d)) (output 2 is an inverted signal of output 1). In the present embodiment, the multivibrator MB41 operates according to the rising edge of the input signal. However, the present invention is not limited to this, and the multivibrator MB41 may be configured to operate according to the falling edge of the input signal. In this case, the logic of the detection signal output from the photocoupler PC41 may be changed as appropriate.

  Note that the fixed period during which the multivibrator MB41 outputs the “H” signal from the output 1 after detecting the rising edge of the input signal is set to about 18 ms. This is a time between 16.7 ms and 20 ms because the period of the 50 Hz AC voltage is about 20 ms and the period of the 60 Hz AC voltage is about 16.7 ms.

  The control circuit 4 has a multivibrator MB42 to which the output 2 signal of the multivibrator MB41 is input. The multivibrator MB42 has the same function as that of the multivibrator MB41, but the fixed period for outputting the “H” signal from the output 1 after detection of the rising edge of the input signal is set to about 30 ms. The two multivibrators MB41 and MB42 constitute the power monitoring circuit 41 shown in FIG.

  One end of the resistor R41 is connected to the output 1 of the multivibrator MB41, one end of the capacitor C41 and the anode of the diode D41 are connected to the other end of the resistor R41, and the other end of the capacitor C41 is connected to the ground potential. Yes. The cathode of the diode D41 is connected to one end of the resistor R42, and the other end of the resistor R42 is connected to one end of the resistor R41. The resistor R41 and the capacitor C41 constitute a timer circuit 43 that defines an overexcitation output period Ta by a time constant, and the diode D41 and the resistor R42 constitute a timer reset circuit 44 that resets the time count of the timer circuit 43. Yes. The potential at the connection point of the resistor R41 and the capacitor C41 is input as the output of the timer circuit 43 to the base of an NPN bipolar transistor (hereinafter referred to as an NPN transistor) T43.

  The control circuit 4 has resistors R43 and R44 to which the detection signal output from the photocoupler PC41 is input at one end, an emitter connected to the other end of the resistor R43, and a base connected to the output 1 of the multivibrator MB42. A PNP bipolar transistor (hereinafter referred to as a PNP transistor) T41, and a capacitor C42 having the other end of the resistor R44 and the collector of the PNP transistor T41 connected to one end and the other end connected to the ground potential. Yes. Resistors R43, R44, PNP transistor T41, and capacitor C42 constitute a time constant switching circuit 42 that switches the control timing of the SCR 21 in accordance with the cycle of the AC voltage V1. The potential at one end of the capacitor C42 is input to the base of the NPN transistor T42 as the output of the time constant switching circuit 42.

  The NPN transistor T43 to which the output of the timer circuit 43 is input to the base has the collector connected to the power supply potential via the resistor R45, the base connected to the NPN transistor T44, and the emitter connected to the ground potential. The NPN transistor T42 to which the output of the time constant switching circuit 42 is input to the base has a collector connected to the collector of the NPN transistor T44 and an emitter connected to the ground potential. The cathode of the light emitting diode D42 whose anode is connected to the power supply potential is connected to one end of the resistor R46, the other end of the resistor R46 is connected to the collector of the NPN transistor T44, and the emitter of the NPN transistor T44 is connected to the ground potential. It is connected. The power supply potential to which the resistor R45 and the light emitting diode D42 are connected may be from a power supply circuit that supplies a DC voltage for the control circuit 4, may be from an external DC power supply, or A battery or a power supply source such as a battery may be used.

  The NPN transistors T42, T43 and T44, the resistors R45 and R46, and the light emitting diode D42 constitute a drive circuit 45. The light-emitting diode D42 is a light-emitting diode that forms a light-emitting element such as a photocoupler or phototriac, and the output of the light-receiving element (not shown) is input to the gate of the SCR 21 of the switching circuit 2 as the output of the control circuit 4. . Alternatively, the light emitting diode D42 of the control circuit 4 and the SCR 21 of the switching circuit 2 may constitute one phototriac.

  When the frequency of the AC voltage V1 input from the AC power supply 8 is 50 Hz (see FIG. 4A), the cycle is 20 ms. The photocoupler PC41 of the control circuit 4 outputs a detection signal “H” when the AC voltage V1 exceeds the threshold voltage and is applied in the forward direction (see FIG. 4B). The multivibrator MB41 outputs an “H” signal of 18 ms from the output 1 in response to the rising edge of the detection signal output from the photocoupler PC41. Therefore, since the cycle of the AC voltage V1 is 20 ms, the multivibrator MB41 repeatedly outputs an “H” signal of 18 ms and an “L” signal of 2 ms (see FIG. 4C). The multivibrator MB41 repeatedly outputs an “L” signal of 18 ms and an “H” signal of 2 ms from the output 2 (see FIG. 4D).

  When the multivibrator MB41 outputs an “H” signal from the output 1, electric charge is stored in the capacitor C41 through the resistor R41. The base of the NPN transistor T43 is connected to the capacitor C41, and the base potential increases as the capacitor C41 is charged. Therefore, the NPN transistor T43 is off until the electric charge is sufficiently stored in the capacitor C41, and the NPN transistor T43 is turned on after the electric charge is sufficiently stored in the capacitor C41 (see FIG. 4 (h)). The time required for the electric charge to be stored in the capacitor C41 is determined by a time constant depending on the resistance value of the resistor R41 and the capacitance value of the capacitor C41, and this time defines the overexcitation output period Ta.

  When the NPN transistor T43 is off (overexcitation output period Ta), the NPN transistor T44 is turned on with the base potential rising (see FIG. 4 (i)), and the light emitting diode D42, the resistor R46 and the NPN transistor are turned on from the power source. Since the current flows to T44, the light emitting diode D42 emits light (see FIG. 4 (j)), and the SCR 21 of the switching circuit 2 can be turned on to apply a voltage to the load 9. On the other hand, when the overexcitation output period Ta elapses and the NPN transistor T43 is turned on, the base potential of the NPN transistor T44 is lowered and turned off (see FIG. 4 (i)). The light emitting diode D42 does not emit light, and the light emission of the light emitting diode D42 is controlled by turning on / off the NPN transistor T42.

  A signal (see FIG. 4D) output from the output 2 of the multivibrator MB41 is input to the multivibrator MB42. When the AC voltage V1 is 50 Hz, the output 2 of the multivibrator MB41 outputs an “H” signal at a cycle of 20 ms, but the multivibrator MB42 outputs an “H” signal of 30 ms in response to the rising edge of the input signal. Therefore, the “H” signal is continuously output from the output 1 of the multivibrator MB42 (see FIG. 4E).

  The output 1 of the multivibrator MB42 is connected to the base of the PNP transistor T41. When the "H" signal is output from the output 1, the base potential of the PNP transistor T41 rises and turns off (FIG. 4 (f)). reference). In the state where the PNP transistor T41 is turned off, when the output of the photocoupler PC41 is an “H” signal, charge is stored in the capacitor C42 only through the resistor R44, and the output of the photocoupler PC41 is an “L” signal. The electric charge stored in the capacitor C42 is discharged. The base of the NPN transistor T42 is connected to the capacitor C42, and the base potential increases as the capacitor C42 is charged. Therefore, the NPN transistor T42 is turned off until the electric charge is sufficiently stored in the capacitor C42, and the NPN transistor T42 is turned on after the electric charge is sufficiently stored in the capacitor C42 (see FIG. 4G). The time required for the electric charge to be stored in the capacitor C42 is determined by a time constant depending on the resistance value of the resistor R44 and the capacitance value of the capacitor C42, and the timing for switching the conduction / non-conduction of the SCR 21 is defined by this time.

  As described above, until the overexcitation output period Ta elapses, the light emitting diode D42 emits light by turning on the NPN transistor T44. In contrast, after the elapse of the overexcitation output period Ta, when the NPN transistor T42 is on, current flows from the power source to the light emitting diode D42, the resistor R46, and the NPN transistor T42, so that the light emitting diode D42 emits light. (Refer to FIG. 4 (j)), the SCR 21 of the switching circuit 2 can be turned on to apply a voltage to the load 9.

  When the input of the AC voltage V1 from the AC power supply 8 is stopped, the photocoupler PC41 continues to output the “L” signal, and the output 1 of the multivibrator MB41 continues to output the “L” signal. The electric charge stored in is discharged through the diode D41 and the resistor R42. As a result, when the input of the AC voltage V1 is resumed, no charge is stored in the capacitor C41, and the NPN transistor T43 is turned off to perform overexcitation output.

  When the frequency of the AC voltage V1 input from the AC power supply 8 is 60 Hz (see FIG. 5A), the cycle is about 16.7 ms. The photocoupler PC41 of the control circuit 4 outputs an “H” detection signal when the AC voltage V1 exceeds the threshold voltage and is applied in the forward direction (see FIG. 5B). The multivibrator MB41 outputs an “H” signal of 18 ms from the output 1 in response to the rising edge of the detection signal output from the photocoupler PC41. Therefore, since the cycle of the AC voltage V1 is 16.7 ms, the multivibrator MB41 continues to output the “H” signal from the output 1 (see FIG. 5C) and continues to output the “L” signal from the output 2. (See FIG. 5 (d)).

  As the multivibrator MB41 continues to output the “H” signal from the output 1, electric charge is stored in the capacitor C41 through the resistor R41. The base of the NPN transistor T43 is connected to the capacitor C41, and the base potential increases as the capacitor C41 is charged. Therefore, the NPN transistor T43 is off until the electric charge is sufficiently stored in the capacitor C41, and the NPN transistor T43 is turned on after the electric charge is sufficiently stored in the capacitor C41 (see FIG. 5 (h)). The time required for the electric charge to be stored in the capacitor C41 is determined by a time constant depending on the resistance value of the resistor R41 and the capacitance value of the capacitor C41, and this time defines the overexcitation output period Ta.

  When the NPN transistor T43 is off (overexcitation output period Ta), the base potential rises and the NPN transistor T44 is turned on (see FIG. 5 (i)), so that the light emitting diode D42, the resistor R46 and the NPN are turned on from the power source. Since the current flows to the transistor T44, the light emitting diode D42 emits light (see FIG. 5J), and the SCR 21 of the switching circuit 2 is turned on, so that the voltage can be applied to the load 9. On the other hand, when the NPN transistor T43 is turned on after the overexcitation output period Ta has elapsed, the base potential of the NPN transistor T44 is lowered and turned off (see FIG. 5 (i)). The light emitting diode D42 does not emit light, and the light emission of the light emitting diode D42 is controlled by turning on / off the NPN transistor T42.

  As described above, the operations of the timer circuit 43, the timer reset circuit 44, and the drive circuit 45 are substantially the same regardless of whether the frequency of the AC power supply V1 is 50 Hz or 60 Hz.

  A signal (see FIG. 5D) output from the output 2 of the multivibrator MB41 is input to the multivibrator MB42. When the AC voltage V1 is 60 Hz, since the “L” signal is continuously output from the output 2 of the multivibrator MB41, the “L” signal is continuously output from the output 1 of the multivibrator MB42 (see FIG. 5E). .

  The output 1 of the multivibrator MB42 is connected to the base of the PNP transistor T41. When the “L” signal is output from the output 1, the PNP transistor T41 is turned on with the base potential decreased (FIG. 5 (f)). reference). With the PNP transistor T41 turned on, when the output of the photocoupler PC41 is an “H” signal, electric charge is stored in the capacitor C42 via the two resistors R43 and R44, and the output of the photocoupler PC41 is “L”. In the case of a signal, the electric charge stored in the capacitor C42 is discharged. The base of the NPN transistor T42 is connected to the capacitor C42, and the base potential increases as the capacitor C42 is charged. Therefore, the NPN transistor T42 is off until the electric charge is sufficiently stored in the capacitor C42, and the NPN transistor T42 is turned on after the electric charge is sufficiently stored in the capacitor C42 (see FIG. 5G). The time required for the electric charge to be stored in the capacitor C42 is determined by a time constant depending on the combined resistance value of the two resistors R43 and R44 and the capacitance value of the capacitor C42, and the timing for switching the conduction / non-conduction of the SCR 21 by this time. Is defined.

  Until the overexcitation output period Ta elapses, the light emitting diode D42 emits light by turning on the NPN transistor T44. In contrast, after the elapse of the overexcitation output period Ta, when the NPN transistor T42 is on, current flows from the power source to the light emitting diode D42, the resistor R46, and the NPN transistor T42, so that the light emitting diode D42 emits light. (Refer to FIG. 5 (j)), the SCR 21 of the switching circuit 2 can be turned on to apply a voltage to the load 9.

  When the frequency of the AC voltage V1 is 50 Hz, the PNP transistor T41 is turned off. Therefore, the timing for controlling the SCR 21 is defined by a time constant based on the resistance value of the resistor R44 and the capacitance value of the capacitor C42. On the other hand, since the PNP transistor T41 is turned on when the frequency of the AC voltage V1 is 60 Hz, the timing for controlling the SCR 21 is a time constant based on the combined resistance value of the two resistors R43 and R44 and the capacitance value of the capacitor C42. Stipulated in Since the two resistors R43 and R44 are connected in parallel, when the frequency of the AC voltage V1 is 60 Hz, the capacitor C42 accumulates charges faster, and the SCR 21 can be conducted at an earlier timing.

  6 and 7 are schematic diagrams for explaining switching of the time constant by the time constant switching circuit 42. FIG. 6 shows the case where the frequency of the AC voltage V1 is 50 Hz, and FIG. 7 shows the AC voltage V1. The case where the frequency is 60 Hz is shown. 6 and 7, the waveform shown in (a) is the AC voltage V1. Further, (b1) and (b2) are waveforms of the output voltage V3 of the DC power supply device not provided with the time constant switching circuit 42, and (b1) is a case where the time constant is set to be suitable for a frequency of 50 Hz. b2) is a case where a time constant is set so as to be suitable for a frequency of 60 Hz. (C) is a waveform of the output voltage V3 of the DC power supply device of the present invention having the time constant switching circuit 42.

  For example, when the frequency of the AC voltage V1 is 50 Hz, the output to the load 9 is 45 VDC (representing a voltage corresponding to 45 V when converted to a DC voltage, the same applies hereinafter). A time constant is set so that the SCR 21 of the switching circuit 2 is turned on at timing (see FIG. 6B1). When a time constant is set so as to be suitable for a frequency of 50 Hz, when an AC voltage V1 having a frequency of 60 Hz is input to this DC power supply device, the conduction timing of the SCR 21 is delayed and the output to the load 9 is reduced to about 31 VDC (FIG. 7 ( b1)).

  Also, for example, when the frequency of the AC voltage V1 is 60 Hz, the time constant is set so that the SCR 21 of the switching circuit 2 is turned on at a timing of 4.17 ms from the rise of the AC voltage V1 so that the output to the load 9 is 45 VDC. (See FIG. 7 (b2)). When a time constant is set so as to be suitable for a frequency of 60 Hz, when an AC voltage V1 having a frequency of 50 Hz is input to this DC power supply device, the conduction timing of the SCR 21 is early, and the output to the load 9 rises to about 57 VDC (FIG. 6). (Refer to (b2)).

  The DC power supply device of the present invention includes a time constant switching circuit 42, and the timing for turning on the SCR 21 is determined by the time constant of the resistor R44 and the capacitor C42 when the frequency is 50 Hz, and when the frequency is 60 Hz. It is determined by the time constants of the resistors R43 and R44 and the capacitor C42. Therefore, a time constant based on the resistance value of the resistor R44 and the capacitance value of the capacitor C42 is set so as to be suitable for the frequency 50 Hz, and the combined resistance value of the resistors R43 and R44 and the capacitance value of the capacitor C42 are suitable for the frequency 60 Hz. A time constant can be set.

  Thus, when an AC voltage V1 having a frequency of 50 Hz is input, the SCR 21 can be conducted at a timing of 5 ms from the rising of the AC voltage V1 with a time constant by the resistor R44 and the capacitor C42 (FIG. 6 ( c)), the output to the load 9 can be 45 VDC. In addition, when an AC voltage V1 having a frequency of 60 Hz is input, the SCR 21 can be conducted at a timing of 4.17 ms from the rising of the AC voltage V1 with a time constant by the resistors R43 and R44 and the capacitor C42 ( As shown in FIG. 7C, the output to the load 9 can be 45 VDC.

  In the DC power supply device having the above configuration, when the input of the AC voltage V1 by the AC power supply 8 is stopped, the energization of the load 9 is cut off without using a contact relay as in the prior art. By adopting a configuration in which the cutoff circuit 3 performs using the field effect transistor T31 that is a semiconductor switching element, it is possible to extend the life and size of the DC power supply device compared to the case of using a contact relay. Further, a field effect transistor T31 is connected in series to the load 9, two resistors R31 and R32 are connected in series between the outputs of the full-wave rectifier circuit 1, and a zener diode ZD31 and a capacitor C31 are connected to the resistor R32 on the low potential side. Are connected in parallel, and the potential at the connection point of the resistors R31 and R32 is input to the gate of the field effect transistor T31, so that the field effect transistor T31 is changed according to the decrease in the output voltage V2 of the full-wave rectifier circuit 1. Since it can be made non-energized, the current flowing through the load 9 can be quickly cut off by the field effect transistor T31 when the input of the AC voltage V1 by the AC power supply 8 is stopped.

  In addition, the configuration is such that the application / non-application of the voltage V2 full-wave rectified by the full-wave rectifier circuit 1 to the load 9 is switched using the SCR 21 of the switching circuit 2, and the three diodes D11 to D13 and one SCR 11 are bridge-connected. The full-wave rectifier circuit 1 is configured to control the conduction / non-conduction of the SCR 11 to provide a period Tb during which the full-wave rectification circuit 1 stops voltage output, so that the SCR 21 of the switching circuit 2 is changed from the conduction state to the non-conduction state. In order to switch to, it is necessary to stop the current flowing through the SCR 21 for a certain period, but since this can be realized by the period Tb, the SCR 21 can be reliably switched from the conductive state to the non-conductive state, and the load using the SCR 21 The voltage application control to 9 can be reliably performed.

  Further, by connecting the diode D14 and the resistor R11 in series between the gate and the anode of the SCR 11 of the full-wave rectifier circuit 1 and controlling the conduction / non-conduction of the SCR 11, the resistor R11 and the diode D14 are controlled. Thus, during the period until the current flowing to the gate of the SCR 11 exceeds a certain amount, the output of the full-wave rectifier circuit 1 can be stopped, and the above-described period Tb can be provided easily and reliably. Further, since the current flowing through the gate of the SCR 11 can be adjusted by adjusting the resistance value of the resistor R11, the period Tb can be easily adjusted.

  Further, the output voltage V2 of the full-wave rectifier circuit 1 is continuously applied to the load 9 from the start of input of the AC voltage V1 until the overexcitation output period Ta determined by the timer circuit 43 elapses, and the overexcitation output period After the lapse of Ta, the output voltage V2 of the full-wave rectifier circuit 1 is periodically applied to the load 9, so that a high voltage can be applied to the load 9 during the overexcitation output period Ta (ie, Overexcitation output can be performed), and after the overexcitation output period Ta elapses, the voltage applied to the load 9 can be reduced to reduce current consumption.

  When the input of the AC voltage V1 is stopped with respect to the time constant circuit including the resistor R41 and the capacitor C41 of the timer circuit 43 that determines the overexcitation output period Ta, the timer reset circuit 44 is stored in the capacitor C41. With the configuration in which the electric charge is discharged, even when the input of the AC voltage V1 is resumed immediately thereafter, there is a problem that the time of the overexcitation output period Ta by the timer circuit 43 is shortened. Without over-excitation output to the load 9 without fail.

  Further, the timing for switching conduction / non-conduction of the SCR 21 after the overexcitation output period Ta has elapsed is defined by a time constant circuit of resistors R43 and R44 and a capacitor C42, and the time constant of the time constant circuit is defined as an AC voltage. By setting it as the structure adjusted according to the frequency of V1, the output voltage to the load 9 can be kept constant, without being influenced by the frequency of AC voltage V1. Further, a detection signal corresponding to a change in the AC voltage V1 by the photocoupler PC41 is input to the multivibrator MB41, and a period in which the multivibrator MB41 outputs an “H” signal from the output 1 is set to a period of 20 ms and a frequency of 60 Hz. By setting it to 18 ms between the period 16.7 ms, it is possible to easily determine whether the frequency of the AC voltage V1 is 50 Hz or 60 Hz using the multivibrator MB41, and the AC voltage V1 The time constant according to the frequency can be adjusted reliably and at low cost.

  In this embodiment, the load 9 is a non-excited electromagnetic brake coil. However, the load 9 is not limited to this, and may be another load such as an electromagnetic clutch coil. Further, the AC power supply 8 that inputs the AC voltage V1 to the DC power supply device may be a commercial AC power supply, or may be another AC power supply that is not a commercial AC power supply. Further, although the field effect transistor T31 is used as a semiconductor switching element that cuts off the current flowing through the load 9, the present invention is not limited to this, and a structure that cuts off the current using a bipolar transistor may be used. The input / output voltage waveforms shown in FIGS. 2 and 4 to 7 are examples, and are not limited thereto. Further, the circuit configuration of the control circuit 4 shown in FIG. 3 is an example and is not limited to this.

It is a circuit diagram which shows the structure of the DC power supply device which concerns on this invention. It is a schematic diagram for demonstrating operation | movement of the DC power supply device which concerns on this invention. It is a circuit diagram which shows an example of a detailed structure of a control circuit. It is a schematic diagram for demonstrating operation | movement of a control circuit in case the frequency of alternating voltage is 50 Hz. It is a schematic diagram for demonstrating operation | movement of a control circuit in case the frequency of alternating voltage is 60 Hz. It is a schematic diagram for demonstrating switching of the time constant by a time constant switching circuit. It is a schematic diagram for demonstrating switching of the time constant by a time constant switching circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Full wave rectification circuit 2 Switching circuit 3 Shut-off circuit 4 Control circuit 8 AC power supply 9 Load 41 Power supply monitoring circuit 42 Time constant switching circuit (time constant circuit)
43 Timer circuit (time constant circuit)
44 Timer reset circuit (discharge circuit)
45 Drive circuit C31, C41, C42 Capacitor D11-D14, D21, D41 Diode D42 Light emitting diode MB41, MB42 Multivibrator PC41 Photocoupler R11, R31, R32, R41-R46 Resistor SCR11, SCR21 Silicon controlled rectifier T31 Field effect transistor (Semiconductor switching element)
T41 PNP transistor T42 to T44 NPN transistor ZD31 Zener diode

Claims (6)

A full-wave rectifier circuit that full-wave rectifies the input AC voltage and outputs a DC voltage; a switching circuit that switches application / non-application of the DC voltage output from the full-wave rectifier circuit to the electromagnetic brake; and the switching circuit a DC electromagnetic brake power supply device and a control circuit for controlling the switching of,
A semiconductor switching element arranged in a path of a current flowing through the electromagnetic brake by application of the DC voltage, the current from the semiconductor switching element after the input of the AC voltage is stopped and the energization to the electromagnetic brake is terminated Equipped with a shutoff circuit that shuts off
The switching circuit has a silicon controlled rectifier for switching between application / non-application,
The full-wave rectifier circuit includes a bridge-connected three diodes and one silicon controlled rectifiers, the control of the silicon controlled rectifier, Ri Citea so as to provide an output stop period of the DC voltage,
The control circuit includes:
Apply a high voltage to the brake by continuously applying the DC voltage until a predetermined period has elapsed from the start of AC voltage input,
After the elapse of the predetermined period, the application time is adjusted so that a low voltage can be applied to the electromagnetic brake by repeating the application / non-application of the DC voltage.
Controlling the switching of the switching circuit;
The DC power supply device for an electromagnetic brake , wherein the application time is less than half of the cycle of the AC voltage . The DC power supply device for an electromagnetic brake according to claim 1, wherein the full-wave rectifier circuit includes a diode and a resistor connected in series between a gate and an anode of the silicon controlled rectifier element. The semiconductor switching element is connected in series to the electromagnetic brake ,
A diode connected in parallel to the electromagnetic brake and the semiconductor switching element connected in series;
The DC power supply device for an electromagnetic brake according to claim 1 or 2, wherein the cutoff circuit is configured to cut off by the semiconductor switching element in accordance with an output voltage of the full-wave rectifier circuit. The interruption circuit is
A first resistor and a second resistor connected in series between a high-potential side output and a low-potential side output of the full-wave rectifier circuit;
A capacitor and a zener diode respectively connected in parallel to the second resistor;
Have
The semiconductor switching element is controlled according to the voltage between the first resistor and the second resistor.
The DC power supply device for electromagnetic brakes according to any one of claims 1 to 3. The control circuit includes:
A time constant circuit of resistors and capacitors for determining the application time;
A photocoupler that detects a positive amplitude period or a negative amplitude period of an input AC voltage, and
To determine the frequency of the AC voltage based on a detection result of the photo-coupler, any of claims 1 to 4, characterized in that in response to the frequency are to adjust the time constant of the time constant circuit The DC power supply device for electromagnetic brakes as described in any one . The control circuit includes:
A resistor and capacitor time constant circuit for determining the predetermined period;
When the input AC voltage is stopped, according to any one of claims 1 to 5, characterized in that it has a discharge circuit for discharging the charge stored in the capacitor of the time constant circuit DC power supply for electromagnetic brakes .

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