JP2021132492A - Power source device - Google Patents

Abstract

To provide a power source device which can be protected even when power to be supplied thereto is in shortage.SOLUTION: A power source device comprises: rectification means rectifying an AC voltage output from an AC power source to a DC voltage; an inductor connected to an output side of the rectification means; first switching means which is arranged between the output terminals of the rectification means, and is installed on a post stage side of the inductor; smoothing means connected to the first switching means in parallel and smoothing the DC voltage output by the rectification means; a diode preventing reverse flow of current to the first switching means from the smoothing means; current limit means arranged in a route where current flows to the rectification means from the first switching means; second switching means connected to the current limit means in parallel; operation detection means detecting operation of the first switching means; and control means setting the second switching means to be in an open state when the operation detected by the operation detection means indicates a short-circuited state of the first switching means.SELECTED DRAWING: Figure 4

Description

The present invention relates to a power supply device.

In a power supply device, there is known a technique for controlling an inrush current prevention relay that switches between passing a current or short-circuiting an inrush current prevention resistor arranged on the input side according to a detected value of the input current.

As a power supply device for controlling such an inrush current prevention relay, a rectifier that rectifies the input AC voltage, a smoothing capacitor that smoothes the rectified voltage, a resistor that limits the inrush current input to the smoothing capacitor, and a current in the resistor. It has a relay for controlling whether or not to input, a current detection circuit, and a converter connected to the subsequent stage of the smoothing capacitor and adjusting the voltage smoothed by the smoothing capacitor to a predetermined voltage, and is a current detection circuit. Discloses what controls whether or not the resistance is enabled according to the flowing current (for example, Patent Document 1). In this device, when a current of a predetermined value or more flows (when a short-circuit current is detected), the relay coil is turned off and a short-circuit current is passed through a resistor having a high impedance to protect the power supply device.

However, in the technique described in Patent Document 1, for example, when power is supplied by wiring in a tucked-in state, or when the power capacity of the indoor power supply equipment is not sufficient, a short circuit occurs and a short circuit current flows. However, there is a problem that the current does not flow to the above-mentioned predetermined value, the resistor that limits the inrush current is not effective, and the power supply device may not be protected.

The present invention has been made in view of the above, and an object of the present invention is to provide a power supply device capable of protecting a power supply device even when the power supply supplied is insufficient.

In order to solve the above-mentioned problems and achieve the object, the present invention comprises a rectifying means for rectifying an AC voltage output from an AC power supply to a DC voltage, an inductor connected to the output side of the rectifying means, and the above. The first switching means arranged between the output ends of the rectifying means and installed on the rear side of the inductor is connected in parallel with the first switching means to smooth the DC voltage output by the rectifying means. The smoothing means, the diode that prevents the backflow current from the smoothing means to the first switching means, the current limiting means arranged in the path flowing from the first switching means to the rectifying means, and the current limiting means in parallel. When the second switching means connected to, the motion detecting means for detecting the operation of the first switching means, and the operation detected by the motion detecting means indicate a short-circuit state of the first switching means, the second It is characterized by being provided with a control means for opening the switching means.

According to the present invention, the power supply device can be protected even when the supplied power supply is insufficient.

FIG. 1 is a diagram illustrating a case where a sufficient current cannot be drawn into the power supply device in the event of an abnormality. FIG. 2 is a diagram showing an example of the configuration of a conventional power supply device. FIG. 3 is a diagram showing a fuse blowing characteristic. FIG. 4 is a diagram showing an example of the configuration of the power supply device according to the embodiment. FIG. 5 is a diagram showing an example of current and voltage states when a short circuit occurs. FIG. 6 is a diagram illustrating an operation of correcting the threshold value for determining the short circuit time.

Hereinafter, the power supply device according to the present invention will be described in detail with reference to the accompanying drawings. Further, the present invention is not limited by the following embodiments, and the components in the following embodiments include those easily conceived by those skilled in the art, substantially the same, and so-called equivalent ranges. Is included. Furthermore, various omissions, substitutions, changes and combinations of components can be made without departing from the gist of the following embodiments.

(An example of a state in which sufficient current does not flow to the power supply device in the event of an abnormality)
FIG. 1 is a diagram illustrating a case where a sufficient current cannot be drawn into the power supply device in the event of an abnormality. With reference to FIG. 1, a case where a sufficient current cannot be drawn into the power supply device when a short circuit occurs will be described.

In FIG. 1, power is supplied from the indoor power supply equipment 201 that supplies power to various indoor electronic devices to the other electronic devices 211, 212, and the power supply device 101 from the wiring that is in a state of being squeezed by the power strip 202. Indicates the state of In this case, since the power supply from the indoor power supply equipment 201 is distributed to each electronic device, the power supply (electric power) supplied to the power supply device 101 may be insufficient. Further, even when the power supply capacity of the indoor power supply equipment 201 itself is not sufficient or the power supply capacity is limited for some reason, the power supply (electric power) supplied to the power supply device 101 may be insufficient. In such a case, when a short circuit occurs in the circuit inside the power supply device 101 due to a foreign substance or the like, a large short circuit current normally flows, but even if a short circuit occurs, a sufficient current is drawn into the power supply device 101. Occurs a situation where it cannot be done.

(About conventional power supply)
FIG. 2 is a diagram showing an example of the configuration of a conventional power supply device. FIG. 3 is a diagram showing a fuse blowing characteristic. With reference to FIGS. 2 and 3, problems of the configuration of the conventional power supply device 101 and the protective operation will be described.

The conventional power supply device 101 shown in FIG. 2 is a power supply device that converts an AC voltage into a DC voltage and supplies a DC power supply. The power supply device 101 includes an AC power supply 111, an input fuse 112, a diode bridge 113, an inrush current prevention resistor 114, an inrush current prevention relay 115, an inductor 116, a switching element 117, a diode 118, and a smoothing capacitor 119. And.

The AC power supply 111 is a power supply that supplies an AC voltage. The input fuse 112 is an electronic component that is blown by Joule heat to protect the circuit when the current flowing from the AC power supply 111 becomes a large current of a predetermined value or more. The diode bridge 113 is an electronic component that full-wave rectifies the AC voltage from the AC power supply 111 and converts it into a DC voltage.

The inrush current prevention resistor 114 is a resistor that protects the circuit by allowing a current to flow through itself having a high impedance when the current I based on the DC voltage rectified from the diode bridge 113 becomes excessive for some reason (short circuit, etc.). It is a vessel. The inrush current prevention relay 115 is a relay for switching between passing a current through the inrush current prevention resistor 114 and short-circuiting both ends of the inrush current prevention resistor 114 according to the control by the control means 132 described later. The inrush current prevention relay 115 includes a switching element 115a and a coil 115b. The switching element 115a is a switching means that is opened and closed by turning the coil 115b on and off to switch whether or not to short-circuit the inrush current prevention resistor 114. The coil 115b is an electronic component that operates on and off according to the control of the control means 132 to open and close the switching element 115a.

The inductor 116, the switching element 117 and the diode 118 form a PFC (Power Factor Direction) circuit (power factor improvement circuit), and the function of the inductor 116 and the rectifying function of the diode 118 (prevention of backflow from the smoothing capacitor 119 to the switching element 117). ), And the opening / closing operation of the switching element 117 suppresses the generation of harmonic currents and improves the power factor of the power supply device 101. The smoothing capacitor 119 is a capacitor that smoothes the DC voltage converted from the AC voltage by the diode bridge 113.

The power supply 101 further includes a transformer 120, a switching element 121, a diode 122, a secondary smoothing capacitor 123, a capacitor 124, and a diode 125.

The transformer 120 has a primary winding 120a and a secondary winding 120b, and the DC voltage smoothed by the smoothing capacitor 119 causes an alternating current to flow in the primary winding 120a by the opening / closing operation of the switching element 121. Then, as for the AC current flowing through the primary winding 120a, an AC voltage corresponding to the winding ratio of the transformer 120 is generated in the secondary winding 120b. Then, the AC voltage generated in the secondary winding 120b is rectified by the diode 122 and smoothed by the secondary side smoothing capacitor 123. Then, the voltage across the secondary smoothing capacitor 123 (DC voltage) becomes the output voltage of the power supply device 101.

Further, the transformer 120 has an auxiliary winding 120c, and a voltage is generated across the auxiliary winding 120c by the opening / closing operation of the switching element 121, a current flows through the diode 125, and the capacitor 24 is charged. A DC voltage is generated from both ends of the 24.

The power supply device 101 further includes a current detecting means 131 and a control means 132.

The current detecting means 131 is an electronic component that detects the value of the current I flowing into the diode bridge 113, and transmits the detected current value to the control means 132. The control means 132 is a control device that controls the operation of the inrush current prevention relay 115 based on the current value detected by the current detection means 131. Specifically, when the control means 132 determines that the current value detected by the current detection means 131 is equal to or higher than a predetermined threshold due to the generation of a short-circuit current or the like, the coil 115b of the inrush current prevention relay 115 is turned off. The switching element 115a is opened (non-conducting state) so that the current I flows through the inrush current prevention resistor 114. As a result, the excessive short-circuit current is suppressed, and the power supply device 101 can be protected.

In the conventional power supply device 101 having the above configuration, when the power supply supplied by the AC power supply 111 is insufficient due to the state described above in FIG. 1, as shown in FIG. 2, the switching element 117 Consider the case where both ends are short-circuited due to foreign matter. In this case, as shown in FIG. 2, a short-circuit current flows in the direction of the arrow as the current I due to a short circuit at both ends of the switching element 117. The detected current value of the short-circuit current may not reach the threshold value determined by the control means 132 described above. In this case, the control means 132 determines that the current value detected by the current detection means 131 is less than the threshold value, determines that the current value is within the normal current value range, and turns on the coil 115b of the inrush current prevention relay 115. Is continued, and the closed state (conducting state) of the switching element 115a is maintained. Then, the current I, which does not reach the above threshold value but is a large short-circuit current, does not flow through the inrush current prevention resistor 114 and flows without being suppressed in magnitude. Then, as shown by the fuse blowing characteristics of the input fuse 112 shown in FIG. 3, at the current I (current value when there is a tako foot wiring / indoor capacity limit shown in FIG. 3), it takes time for the input fuse 112 to blow. (Or the input fuse 112 does not blow), the cutoff operation of the current flowing in the direction of the arrow in FIG. 2 is delayed, and the internal wiring and electronic parts of the power supply device 101 may be damaged due to ignition or damage. ..

The configuration and operation of the power supply device 1 according to the present embodiment for solving the above-mentioned problems in the conventional power supply device 101 will be described with reference to FIGS. 4 to 6 below.

(Configuration of power supply device according to this embodiment)
FIG. 4 is a diagram showing an example of the configuration of the power supply device according to the embodiment. FIG. 5 is a diagram showing an example of current and voltage states when a short circuit occurs. The configuration and operation of the power supply device 1 according to the present embodiment will be described with reference to FIGS. 4 and 5.

Similar to the power supply device 101, the power supply device 1 shown in FIG. 4 is a power supply device that converts an AC voltage into a DC voltage and supplies a DC power supply. The power supply device 1 includes an AC power supply 11, an input fuse 12, a diode bridge 13 (an example of rectifying means), an inrush current prevention resistor 14 (an example of a current limiting means), an inrush current prevention relay 15, and an inductor 16. , A switching element 17, a switching element 17 (first switching means), a diode 18, and a smoothing capacitor 19 (an example of smoothing means). The inrush current prevention relay 15 has a switching element 15a (second switching means) and a coil 15b. Each of these components includes an AC power supply 111, an input fuse 112, a diode bridge 113, an inrush current prevention resistor 114, and an inrush current prevention relay 115 (switching element 115a, coil 115b) of the power supply device 101 shown in FIG. ), The inductor 116, the switching element 117, the diode 118, and the smoothing capacitor 119 have the same functions.

The power supply device 1 further includes a transformer 20, a switching element 21, a diode 22, a secondary smoothing capacitor 23, a capacitor 24, and a diode 25. The transformer 20 has a primary winding 20a, a secondary winding 20b, and an auxiliary winding 20c. These components are the transformer 120 (primary winding 120a, secondary winding 120b, auxiliary winding 120c), switching element 121, diode 122, and secondary side of the power supply device 101 shown in FIG. 2, respectively. The functions are similar to those of the smoothing capacitor 123, the capacitor 124, and the diode 125.

The power supply device 1 further includes a voltage detecting means 31 (an example of an operation detecting means) and a control means 32. That is, the power supply device 1 includes a voltage detecting means 31 in place of the current detecting means 131 of the power supply device 101, and a control means 32 in place of the control means 132.

As shown in FIG. 5, the voltage detecting means 31 is an electronic component that detects an on / off operation of the switching element 17. Specifically, the voltage detecting means 31 detects the voltage Vds which is the voltage across the switching element 17, and the time when the switching element 17 is in the closed state (conducting state, short-circuited state), that is, the voltage as shown in FIG. Vds detects the Low time (hereinafter, may be referred to as a short circuit time), and transmits the detected short circuit time to the control means 32. The control means 32 is a control device that controls the operation of the inrush current prevention relay 15 based on the short-circuit time of the switching element 17 measured by the voltage detection means 31. Specifically, the control means 32 determines whether or not the short-circuit time detected by the voltage detection means 31 is equal to or greater than a predetermined threshold value, and if it is equal to or longer than the threshold value, the switching element 17 is abnormally short-circuited. The coil 15b of the inrush current prevention relay 15 is turned off to open the switching element 15a (non-conducting state) so that the current I flows through the inrush current prevention resistor 14.

As a result, the excessive short-circuit current is suppressed, and the power supply device 1 can be protected. Further, since the short-circuited state of the switching element 17 can be detected without depending on the current I, power is supplied from the indoor power supply equipment or the like (indoor power supply equipment 201 or the like) by the wiring in which the power supply device 1 is in a slack state. Protect the power supply device 1 even when receiving, or when the power supply capacity of the indoor power supply equipment itself is not sufficient, or when sufficient current cannot be drawn as in the case where the power supply capacity is limited for some reason. Can be done.

The inrush current prevention resistor 14 may be, for example, a thermal fuse resistor. As a result, even if the current I becomes a short-circuit current due to a short circuit of the switching element 17, the internal fuse is blown by Joule heat to cut off the circuit, and the power supply device 1 can be protected more reliably.

Further, the opening / closing operation of the switching element 15a controlled by the control means 32 is performed by an on / off operation with respect to the coil 15b, but the present invention is not limited to this, and for example, a switching element whose opening / closing operation can be controlled by a control signal is a switching element 15a. It may be used instead of.

(About the correction of the threshold value used for the determination processing of the control means)
FIG. 6 is a diagram illustrating an operation of correcting the threshold value for determining the short circuit time. With reference to FIG. 6, the operation of correcting the threshold value for determining the short-circuit time in the control means 32 of the power supply device 1 according to the present embodiment will be described.

The inductor 16, the switching element 17, and the diode 18 shown in FIG. 4 form a PRC circuit (power factor improving circuit), and the function of the inductor 16, the rectifying function of the diode 18, and the opening / closing operation of the switching element 17 cause harmonics. The generation of wave current is suppressed and the power factor of the power supply device 1 is improved. In this case, the duty ratio of the opening / closing operation of the switching element 17 varies depending on the magnitude of the input voltage (voltage Vds) which is the voltage at both ends. Specifically, as shown in FIG. 6A, the switching element 17 has a duty such that the on-time (closed time, short-circuit time) is short when the input voltage is high and long when the input voltage is low. Works in proportion. Therefore, the control means 32 needs to set the threshold value for determining the short-circuit time detected by the voltage detecting means 31 according to the case where the on-time of the switching element 17 is long and the input voltage is low. For example, FIG. In the case of (a), the threshold value needs to be the detection time T1. However, if the threshold value is fixed to the detection time T1, the detection when the switching element 17 is short-circuited is delayed even when the input voltage with a short on-time is high.

Therefore, as shown in FIG. 6B, when the input voltage with a short on-time of the switching element 17 is high, the control means 32 inputs a long on-time by setting the threshold value to the detection time T2, for example. The detection of the short-circuited state of the switching element 17 can be accelerated by T1-T2 as compared with the case of the threshold value (detection time T1) when the voltage is low. In this way, the control means 32 corrects the threshold value for determining the short-circuit time according to the magnitude of the input voltage (voltage Vds) detected by the voltage detection means 31. As a result, the control means 32 can quickly detect the short-circuit state of the switching element 17 by making a determination with an appropriate threshold value according to the operation of the switching element 17.

As described above, in the power supply device 1 according to the present embodiment, the inrush current prevention resistor 14 that limits the current, the switching element 15a connected in parallel to the inrush current prevention resistor 14, and the switching included in the power factor improvement circuit. The presence or absence of a short-circuit state of the switching element 17 is determined according to the operation of the voltage detecting means 31 for detecting the operation of the element 17 and the switching element 17 detected by the voltage detecting means 31, and the occurrence of the short-circuit state is determined. If so, the switching element 15a is opened. As a result, the short-circuited state of the switching element 17 can be detected without depending on the current I. Protects the power supply device 1 even when the power supply capacity of the indoor power supply equipment itself is not sufficient, or when sufficient current cannot be drawn as in the case where the power supply capacity is limited for some reason. be able to.

1 Power supply 11 AC power supply 12 Input fuse 13 Diode bridge 14 Rush current prevention resistor 15 Rush current prevention relay 15a Switching element 15b Coil 16 inductor 17 Switching element 18 Diode 19 Smoothing capacitor 20 Transformer 20a Primary winding 20b Secondary winding 20c Auxiliary Winding 21 Switching element 22 Diode 23 Secondary side smoothing capacitor 24 Condenser 25 Diode 31 Voltage detection means 32 Control means 101 Power supply device 111 AC power supply 112 Input fuse 113 Diode bridge 114 Rush current prevention resistor 115 Rush current prevention relay 115a Switching element 115b Coil 116 inductor 117 switching element 118 diode 119 smoothing capacitor 120 transformer 120a primary winding 120b secondary winding 120c auxiliary winding 121 switching element 122 diode 123 secondary side smoothing capacitor 124 capacitor 125 diode 131 current detection means 132 control means 201 indoors Power supply equipment 202 Power tap 211, 212 Other electronic devices

JP-A-2019-004541

Claims (5)

A rectifying means that rectifies the AC voltage output from the AC power supply to a DC voltage,
The inductor connected to the output side of the rectifying means and
A first switching means arranged between the output ends of the rectifying means and installed on the rear side of the inductor.
A smoothing means that is connected in parallel with the first switching means and smoothes the DC voltage output by the rectifying means.
A diode that prevents backflow current from the smoothing means to the first switching means,
A current limiting means arranged in a path flowing from the first switching means to the rectifying means, and
A second switching means connected in parallel with the current limiting means,
An operation detecting means for detecting the operation of the first switching means and
When the operation detected by the operation detecting means indicates a short-circuited state of the first switching means, the control means for opening the second switching means and the control means.
Power supply with. The operation detecting means is a voltage detecting means for detecting a voltage across the first switching means.
The power supply device according to claim 1, wherein the control means determines whether or not the first switching means is in a short-circuited state based on the voltage across the voltage detected by the voltage detecting means. The voltage detecting means detects the short-circuit time of the first switching means based on the detected voltage across the first switching means.
The power supply device according to claim 2, wherein when the control means determines that the short-circuit time detected by the voltage detecting means is equal to or greater than a predetermined threshold value, the second switching means is opened. The power supply device according to claim 3, wherein the control means corrects the threshold value according to the voltage across the voltage detected by the voltage detecting means. The power supply device according to any one of claims 1 to 4, wherein the current limiting means is a thermal fuse resistor.

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