JP2011101470A - Power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a certain output voltage without manually changing an input supply voltage, even when the input supply voltage differs and simplify circuitry. <P>SOLUTION: A power supply circuit is provided with a voltage detection unit 2 that detects the voltage of input power supply, a voltage conversion unit 4 that converts different voltages of the input power supply into a certain output voltage, and a circuit switching unit 3 using a relay 14 that switches the voltage of the input power supply of the voltage conversion unit 4 based on the result of detection by the voltage detection unit 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply circuit, and more particularly to a power supply circuit for a blower that can handle a plurality of input power supply voltages.

  As a general power source in Japan, an AC power source of 100V or 200V is used, and a 100V device and a 200V device are mixed in the blower. In addition, 120V and 220V AC power supplies are used overseas, and there are dedicated devices. For devices that share power inputs of different voltages, methods for manual switching and automatic switching are known.

  For example, as a method of automatic switching, Patent Document 1 detects a voltage difference between a single-phase 100V and a three-phase 200V, automatically switches between a voltage doubler rectifier circuit and a three-phase full-wave rectifier circuit, and a constant output voltage. Techniques for maintaining the above are disclosed.

JP-A-5-146154

  However, in the method of manually switching power supply inputs of different voltages, there is a possibility that an incorrect voltage may be input, and there is a problem that the apparatus may be damaged. Further, in the method disclosed in Patent Document 1, the configuration of the power supply circuit is complicated because the voltage doubler rectifier circuit and the three-phase full-wave rectifier circuit are automatically switched, so that the air passage such as a ventilation fan is secured and installed. There was a problem that it was difficult to mount on a blower with limited space.

  The present invention has been made in view of the above, and it is possible to generate a constant output voltage and to simplify the configuration without manually switching the input power supply voltage even when the input power supply voltages are different. The purpose is to obtain a power supply circuit capable of performing

  In order to solve the above-described problems and achieve the object, a power supply circuit of the present invention includes a voltage detection unit that detects a voltage of an input power supply, and a voltage conversion unit that converts a different voltage of the input power supply into a constant output voltage. And a circuit switching unit using a relay for switching the voltage of the input power source of the voltage conversion unit based on a detection result by the voltage detection unit.

  According to the present invention, even when the input power supply voltages are different, there is an effect that it is possible to generate a constant output voltage and to simplify the configuration without manually switching the input power supply voltage.

FIG. 1 is a block diagram showing a schematic configuration of a power supply circuit according to Embodiment 1 of the present invention. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the voltage conversion unit 4 of FIG. FIG. 3 is a block diagram showing an example of a schematic configuration of the voltage conversion unit 4a and the circuit switching unit applied to the second embodiment of the power supply circuit according to the present invention. FIG. 4 is a block diagram showing an example of a schematic configuration of the voltage conversion unit 4b and the circuit switching unit applied to the third embodiment of the power supply circuit according to the present invention. FIG. 5 is a block diagram showing a schematic configuration of the fourth embodiment of the power supply circuit according to the present invention. FIG. 6 is a block diagram showing a schematic configuration of the power supply circuit according to Embodiment 5 of the present invention. FIG. 7 is a block diagram showing an example of a schematic configuration of the voltage conversion unit 4c applied to the sixth embodiment of the power supply circuit according to the present invention. FIG. 8 is a block diagram showing a schematic configuration of the seventh embodiment of the power supply circuit according to the present invention.

  Hereinafter, embodiments of a power supply circuit according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a schematic configuration of a power supply circuit according to Embodiment 1 of the present invention. In the following description, it is assumed that the AC input power source 1 is used in general AC 100V and AC 200V in Japan, and the load 5 is assumed to be an AC motor for a blower with AC 100V input. In FIG. 1, the AC input power supply 1 uses a single-phase 100V or single-phase 200V commercial power input. The AC input power source 1 is connected to the voltage detection unit 2 and the circuit switching unit 3.

  The voltage detection unit 2 is a circuit that detects whether the voltage of the AC input power supply 1 is 100 V or 200 V, and is mainly provided with a diode bridge 6, voltage dividing resistors 9 and 10, and a Zener diode 11. Here, a resistor 7 is connected in series to the diode bridge 6, and a smoothing capacitor 8 is connected in parallel to the series circuit of the diode bridge 6 and the resistor 7. A series circuit of voltage dividing resistors 9 and 10 is connected in parallel to the smoothing capacitor 8, and a series circuit of a Zener diode 11 and a resistor 12 is connected in parallel to the voltage dividing resistor 10.

  The voltage input from the AC input power source 1 is full-wave rectified by the diode bridge 6 and smoothed by the smoothing capacitor 8. The rectified voltage is divided by the voltage dividing resistors 9 and 10 and applied to the Zener diode 11. Therefore, the voltage applied to the Zener diode 11 varies depending on the voltage of the AC input power source 1 and the values of the voltage dividing resistors 9 and 10.

  Here, the value of the voltage dividing resistors 9 and 10 is set so that the voltage applied to the Zener diode 11 between 100 V and 200 V becomes the Zener voltage, so that when the input voltage is 100 V, the voltage is applied to the Zener diode 11. The applied voltage does not exceed the Zener voltage, and almost no current flows. However, when the voltage is 200 V, the Zener voltage is exceeded, so that the current can flow. The resistor 7 suppresses an inrush current when the power is turned on, and the resistor 12 is a resistor for pull-down.

  The circuit switching unit 3 is a circuit that switches the connection destination of the voltage conversion unit 4 in accordance with the voltage detected by the voltage detection unit 2, and includes a transistor 13 and a two-contact relay 14. Here, the two-contact relay 14 is provided with a coil 41 that detects current and a two-contact switch 42 that operates by electromagnetic force generated from the coil 41. A resistor 32 is connected in series to the transistor 13, and a coil 41 is connected in parallel to the series circuit of the transistor 13 and the resistor 32. The control terminal of the transistor 13 is connected to the connection point between the Zener diode 11 and the resistor 12. A resistor 31 is connected between the resistors 9 and 32.

  Further, since it is necessary to connect the normally closed contact side with the high voltage power supply circuit 15 so that electricity does not flow to the low voltage power supply circuit 16 during the time until the two contact relay 14 operates, A high voltage power supply circuit 15 of the voltage conversion unit 4 is connected to the normally closed contact side, and a low voltage power supply circuit 16 is connected to the normally open contact side.

  When no current flows through the Zener diode 11 of the voltage detection unit 2, the transistor 13 does not operate, so that electricity flows to the coil of the two-contact relay 14, and the two-contact relay 14 operates. Further, when a current flows through the Zener diode 11, the transistor 13 operates, so that electricity does not flow to the two-contact relay 14, and the two-contact relay 14 does not operate. When the voltage of the AC input power supply 1 is 100V, the two-contact relay 14 operates, and when the voltage is 200V, the two-contact relay 14 does not operate.

  The voltage conversion unit 4 is a circuit that generates a voltage matched to the load 5 from input voltages of 100 V and 200 V, and is provided with a high voltage power supply circuit 15 and a low voltage power supply circuit 16. When the voltage of the AC input power supply 1 is assumed to be 100V or 200V, the low voltage power supply circuit 16 generates a voltage matched to the load 5 from the input voltage of 100V, and the high voltage power supply circuit 15 applies to the load 5. A combined voltage can be created from an input voltage of 200V.

  When the voltage of the AC input power source 1 is 100 V, no current flows through the Zener diode 11 of the voltage detection unit 2, so that the transistor 13 of the circuit switching unit 3 does not operate and the two-contact relay 14 operates. When the two-contact relay 14 operates, the connection destination of the AC input power supply 1 is switched to the low-voltage power supply circuit 16 of the voltage conversion unit 4 connected to the normally open contact, and is generated by the low-voltage power supply circuit 16. A voltage matched to the load 5 is supplied to the load 5.

  On the other hand, when the voltage of the AC input power supply 1 is 200 V, a current flows through the Zener diode 11 of the voltage detection unit 2, so that the transistor 13 of the circuit switching unit 3 operates and the two-contact relay 14 does not operate. Since the two-contact relay 14 does not operate, the connection destination of the AC input power supply 1 remains the high voltage power supply circuit 15 of the voltage conversion unit 4 connected to the normally closed contact, and is generated by the high voltage power supply circuit 15. A voltage matched to the load 5 is supplied to the load 5.

  By the above operation, the low voltage power supply circuit 16 is automatically selected when the voltage of the AC input power supply 1 is 100V, and the high voltage power supply circuit 15 is automatically selected when the voltage is 200V. Is converted to, and then supplied to the load 5. Therefore, it is possible to automatically select an appropriate circuit and operate normally for different input voltages without human intervention, and therefore, it is possible to prevent ignition due to misconnection or destruction of equipment.

  FIG. 2 is a block diagram illustrating an example of a schematic configuration of the voltage conversion unit 4 of FIG. In FIG. 2, the high voltage power supply circuit 15 is provided with a step-down transformer 17. In the high-voltage power supply circuit 15, the two-contact relay 14 is connected to the load 5 via the step-down transformer 17, and in the low-voltage power supply circuit 16, the two-contact relay 14 is directly connected to the load 5.

  The high-voltage power supply circuit 15 generates AC100V from AC200V using the step-down transformer 17 and transmits it to the load 5. The low-voltage power supply circuit 16 transmits AC100V to the load 5 as it is. The voltage of 100V can be produced in accordance with the load 5 regardless of whether the voltage of the voltage is 200V or 100V.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing an example of a schematic configuration of the voltage conversion unit 4a and the circuit switching unit applied to the second embodiment of the power supply circuit according to the present invention. 3, in this power supply circuit, a voltage converter 4a and a one-contact relay 18 are provided instead of the voltage converter 4 and the two-contact relay 14 of FIG. Here, a voltage dividing capacitor 19 is provided in the voltage conversion unit 4a. The one-contact relay 18 is provided with a coil 41 and a one-contact switch 43. The normally closed contact side of the 1 contact relay 18 is connected to the load 5 via the voltage dividing capacitor 19, and the normally open contact side of the 1 contact relay 18 is directly connected to the load 5.

  When the voltage of the AC input power source 1 is 200 V, the AC 100 V is generated from the AC 200 V using the voltage dividing capacitor 19 and transmitted to the load 5. When the voltage of the AC input power source 1 is 100 V, the AC 100 V is directly transmitted to the load 5. Thus, regardless of whether the voltage of the AC input power supply 1 is 200 V or 100 V, a voltage 100 V that matches the load 5 can be created.

Embodiment 3 FIG.
FIG. 4 is a block diagram showing an example of a schematic configuration of the voltage conversion unit 4b and the circuit switching unit applied to the third embodiment of the power supply circuit according to the present invention. 4, in this power supply circuit, a voltage converter 4b and a one-contact relay 18 are provided instead of the voltage converter 4 and the two-contact relay 14 in FIG. Here, the voltage conversion unit 4b is provided with a multiple-input transformer 20. The normally closed contact side of the one-contact relay 18 is connected to the load 5 via the 200V input terminal of the multiple-input compatible transformer 20, and the normally-open contact side of the one-contact relay 18 is for 100V input of the multiple-input compatible transformer 20. It is connected to the load 5 via a terminal.

  When the voltage of the AC input power source 1 is 200V, the AC 100V is generated from the AC 200V using the multi-input compatible transformer 20 and transmitted to the load 5. When the voltage of the AC input power source 1 is 100V, the AC 100V is transmitted to the load 5. Thus, regardless of whether the voltage of the AC input power supply 1 is 200 V or 100 V, a voltage 100 V that matches the load 5 can be created.

Embodiment 4 FIG.
FIG. 5 is a block diagram showing a schematic configuration of the fourth embodiment of the power supply circuit according to the present invention. In this power supply circuit, a DC motor is used as a load 51 in FIG. A DC motor drive circuit 21 that drives the DC motor is connected to the subsequent stage of the voltage conversion unit 4. The AC voltage of 100 V AC output from the voltage conversion unit 4 is converted into a DC voltage by the DC motor driving circuit 21 and supplied to the load 51. For this reason, even when a DC motor is used as the load 51 instead of the AC motor, the DC motor can be easily incorporated into the DC motor by incorporating the AC motor 100V input DC motor drive circuit 21 between the voltage converter 4 and the load 51. Is possible.

Embodiment 5 FIG.
FIG. 6 is a block diagram showing a schematic configuration of the power supply circuit according to Embodiment 5 of the present invention. 6, this power supply circuit is different from the power supply circuit of FIG. 1 in that when the voltage of the AC input power supply 1 is 200 V, the two-contact relay 14 operates immediately after the power is turned on. A malfunction prevention function is added to prevent current from flowing accidentally. Specifically, the circuit switching unit 3 is provided with a protective capacitor 22 connected in parallel to the two-contact relay 14.

  When the voltage of the AC input power source 1 is 200 V, the voltage rectified by the diode bridge 6 is smoothed by the smoothing capacitor 8, but a certain time is required until the smoothing capacitor 8 is charged immediately after the power is turned on. Therefore, the voltage applied to the voltage dividing resistor 9 is gradually increased. The Zener diode 11 starts to flow current when it exceeds the Zener voltage. However, since the current does not flow at the same voltage as when 100V is input, the transistor 13 still operates when the operating voltage of the two-contact relay 14 is reached. Not. There is a possibility that the relay 14 operates in a short time from the time when the operating voltage of the two-contact relay 14 is reached to the time when the Zener voltage of the Zener diode 11 is exceeded.

  As such a measure, a protective capacitor 22 is connected in parallel with the two-contact relay 14 so that no current flows through the two-contact relay 14 until the voltage after passing through the smoothing capacitor 8 sufficiently increases. The malfunction of the contact relay can be suppressed. Further, when the voltage of the AC input power supply 1 is 100 V, after the electric charge is accumulated in the protective capacitor 22, a current flows through the two-contact relay 14, so that there is no problem in operation.

Embodiment 6 FIG.
FIG. 7 is a block diagram showing an example of a schematic configuration of the voltage conversion unit 4c applied to the sixth embodiment of the power supply circuit according to the present invention. In FIG. 7, this power supply circuit is obtained by adding a protection function for protecting the voltage converter 4 from a different voltage to the power supply circuit of FIG.

  Usually, the constants of elements used for abnormal voltage protection differ depending on the voltage and current used. For this reason, when using at a different voltage, if a high voltage element is used, if it is used at a low voltage, a sufficient protection function cannot be achieved, and if a low voltage element is used, it is used at a high voltage. May have a protective function in normal operation.

  As such countermeasures, the high voltage power supply circuit 15 in the voltage converter 4 is provided with a fuse 23 and a varistor 24 for 200 V, and the low voltage power supply circuit 16 is provided with a fuse 25 and a varistor 26 for 100 V. Thus, the circuit and the load 5 can be protected at different voltages.

Embodiment 7 FIG.
FIG. 8 is a block diagram showing a schematic configuration of the seventh embodiment of the power supply circuit according to the present invention. In FIG. 8, this power supply circuit is obtained by adding a protection function for protecting the load 5 from different voltages to the power supply circuit of FIG.

  As described above, it is necessary to use an element used for the abnormal voltage protection in accordance with the voltage to be used, but the voltage after passing through the voltage converter 4 is unified with the voltage used in the load 5. For this reason, by providing the fuse 27 and the varistor 28 corresponding to 100V between the voltage conversion unit 4 and the load 5, the load 5 can be protected during an abnormal voltage.

  As described above, the power supply circuit according to the present invention is useful as a power supply circuit that can prevent the risk of equipment destruction or fire due to misconnection even when a 100V or 200V AC power supply is used. In particular, it is suitable as a power supply circuit for a blower where there are restrictions on the place where the power supply is used and the installation space.

DESCRIPTION OF SYMBOLS 1 AC input power supply 2 Voltage detection part 3 Circuit switching part 4, 4a, 4b Voltage conversion part 5, 51 Load 6 Diode bridge 7, 12, 31, 32 Resistance 8 Smoothing capacitor 9, 10 Voltage dividing resistor 11 Zener diode 13 Transistor 14 Two-contact relay 15 High-voltage power circuit 16 Low-voltage power circuit 17 Step-down transformer 18 One-contact relay 19 Voltage divider capacitor 20 Multiple input transformer 21 DC motor drive circuit 22 Protection capacitor 23 High-voltage fuse 24 High-voltage varistor 25 Low voltage fuse 26 Low voltage varistor 27 Load voltage fuse 28 Load voltage varistor 41 Coil 42 Two contact switch 43 One contact switch

Claims (8)

A voltage detector that detects the voltage of the input power supply;
A voltage converter for converting different voltages of the input power source into a constant output voltage;
A power supply circuit comprising: a circuit switching unit using a relay that switches a voltage of an input power supply of the voltage conversion unit based on a detection result by the voltage detection unit.   The voltage conversion unit includes a step-down transformer, and the circuit switching unit switches the voltage of the input power source so as not to be stepped down by the step-down transformer when a low voltage is detected by the voltage detection unit. 2. The power supply circuit according to claim 1, wherein when a high voltage is detected in the unit, switching is performed so that the voltage of the input power supply is stepped down by the step-down transformer.   The voltage conversion unit includes a voltage dividing capacitor, and the circuit switching unit switches so that the voltage of the input power source is not divided by the voltage dividing capacitor when a low voltage is detected by the voltage detection unit, 2. The power supply circuit according to claim 1, wherein when a high voltage is detected by the voltage detection unit, switching is performed so that the voltage of the input power supply is divided by the voltage dividing capacitor.   The power supply circuit according to claim 1, wherein the voltage conversion unit includes a transformer corresponding to a plurality of input voltages.   5. The power supply circuit according to claim 1, further comprising a DC motor drive circuit connected to a subsequent stage of the voltage conversion unit. 6.   6. The device according to claim 1, further comprising a protective capacitor provided in the circuit switching unit and connected in parallel to the relay for preventing current from flowing through the relay immediately after power is turned on. The power supply circuit described in 1.   7. The device according to claim 1, further comprising a protection circuit that is provided in the voltage conversion unit corresponding to the voltage of the input power supply and protects the voltage conversion unit from a different voltage. 8. Power supply circuit.   The circuit further comprises a protection circuit that is provided in a subsequent stage of the voltage converter corresponding to the output voltage of the voltage converter and protects a load supplied with the output voltage of the voltage converter from a different voltage. Item 7. The power supply circuit according to any one of Items 1 to 6.

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